Striking Balance a

A Guide toCoastal Dynamics and

Beach Managementin Delaware

Striking

Balancea

This document was developed with funding from: (1) Delaware Department of NaturalResources and Environmental Control (DNREC), Division of Soil and Water Conservation,Shoreline & Waterway Management Section; and (2) DNREC Delaware Coastal Programs,pursuant to the Coastal Zone Management Act of 1972, as amended, administered by theOffice of Ocean and Coastal Resource Management, National Oceanic and AtmosphericAdministration Award No. NA17OZ2329.

Document No. 40-07-01/04/08/06

O

SStriking a Balance

Our shoreline is a dynamic environment, constantly changing with the effects of waves,

winds, tides, and currents. Coastal evolution and beach erosion are ongoing natural

processes, and it is important to understand and recognize the complex causes and

dynamic forces that created, shape, and continue to maintain this critical resource.

Beach management in Delaware integrates coastal and ecological management principles,

sound planning, and wise design, siting, and construction criteria. The ultimate goals are to

preserve coastal resources, maintain human use and economic resources, and strike a

balance between the realities of nature and impacts of coastal development.

SIntroduction

Second Edition • 2004

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Striking a Balance:A Guide to Coastal Dynamics and Beach Management in Delaware

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40 AppendixesBeach Preservation Regulatory ProgramCoastal Property ChecklistGlossaryDelaware Contact InformationResources for Additional Information

Summary and Conclusions

Beach and Sand Management Strategies

Human Use and DevelopmentAlong the Delaware Coast

The Beach as an Economic Resource

The Beach as a Natural Resource

Beaches and Coastal Processes

IDelaware’s coastal areas are unique resources valued for their naturalbeauty, recreational opportunities, economic benefits, and environmentalsignificance. Each summer, thousands of people visit our many miles ofbeautiful beaches to enjoy the sun, sand, and surf. [1; see photo at right]More and more people are choosing coastal Delaware for their secondhome or primary residence. The wide diversity of available activities suits avariety of tastes and preferences. Beachgoers are attracted to the calmwaters and scenic vistas of marshes along the Delaware Bay; the tranquilityand solitude provided by the natural surroundings of Cape Henlopen,Delaware Seashore and Fenwick Island State Parks; the excitement of avisit to the Rehoboth Beach boardwalk; the challenge of surf fishing forbluefish and sea trout; clamming and wading in the Inland Bays; andboating and sailing in our many coastal waterways. In addition,birdwatchers mark the change of seasons with the comings and goings ofthousands of migratory birds.

Few summertime visitors have witnessed first-hand the unrelentingfury of the sea during a coastal storm. [2] In just a few hours, waves,winds, and tides can dramatically alter the beach by moving vast quantitiesof sand. The wide sandy beach enjoyed during the summer can disappearrapidly as waves wash under the boardwalk or through the dunes.Once the protective beach is eroded, natural features such as dunes,and manmade structures such as homes, businesses, roads, andbridges are subject to the destructive forces of nature.

Delaware’s beaches are dynamic features, changing constantly inresponse to winds, waves, tides, and currents. Unlike most upland areas,which are comparatively stable over time in their natural state, our barrierbeaches are shifting landforms. They have been moving landward due torising sea level since the end of the last Ice Age approximately 15,000 to17,000 years ago. On such a non-permanent landform, development must take place with the understanding andacceptance of the inevitable changes that will occur in the natural environment. Attempts to stabilize and control these

areas can damage the natural system.Placing structures that are expected tolast for decades on a dynamic andconstantly changing landform requires

S T R I K I N G A B A L A N C E ● 1

Introduction

Introduction:

Striking a Balance

Summertime visitors enjoying Rehoboth Beachand the boardwalk.

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2 South Bethany during a coastal storm.

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significant input and analyses from coastal scientistsand engineers, along with integrated coastalmanagement considerations, decisions, and strategies.The science and art of shore protection have evolvedfrom building structures designed to protect buildings(seawalls and bulkheads) to practices that protect andenhance the natural beach (construction setbacks,dune protection, and beach nourishment).

The social value of Delaware’s coast is visuallyevident through the extreme development in place forhousing, tourist facilities, and commercialestablishments. Our beaches host millions of visitorsannually and the coast is the fuel for a large economicengine. The amount of money spent in pursuit of livingnear the coast or for an annual beach vacation, and thejobs that have developed to support this demand are atremendous boost to the Delaware economy. The flowof money and the taxes that are derived from thecoastal service industry are vital to the state’s economy.While social demand for rest and relaxation at thebeach is unparalleled, the very things that attractpeople to the shore are threatened by the sheernumbers of visitors and everything required toaccommodate their needs. [3]

When this booklet was first published in 1985,Delaware’s population was 618,284. By 2003, it hadincreased to 818,010, and is now projected to reach1,007,382 by 2025. In Sussex County alone, thepopulation was 103,943 in 1985, increased to 167,904in 2003, and is expected to reach 247,211 in 2025.Clearly, more people are living near the coast, anddemands for using its natural resources are increasing.

Ideally, beaches should remain totally open andnatural, to be used indefinitely by local residents andvisitors. Realistically, however, land development andre-development will continue in the coastal strip.Proper management and planning, based on scientificinformation, knowledge of basic principles, andcommon sense will ensure compatibility of the manyuses of our coast.

This booklet has been prepared to give you ageneral background and knowledge of coastaldynamics and beach management in Delaware.Understanding the forces affecting the beach isessential to appreciating the delicate balance betweendevelopment and protection of our fragile coastalresources. This publication also explains statewidecoastal management policies and the measures takento mitigate the effects of erosion. ■

Introduction

3 The economic and social values of the Delaware coast are evidentthrough residential and commercial development. Each year, millionsof visitors enjoy Delaware’s beaches, supporting a flourishing economy.

BBeaches and

Coastal Processes

Coastal EnvironmentsTo most people, a beach is the sandy area where land meetsthe sea. To a scientist, a beach is one component of thelarger coastal barrier system that also encompasses manyother associatedenvironments such asoffshore sand bars,dunes, backbarrierflats, and marshes.This entire systemconsists of sediments(sand and mud) thatare continuouslymoved and repositedby winds, waves, tides,and currents. Thesephysical forces areresponsible forchanging the shape ofthis highly dynamicsystem.

The variouscomponents of a natural barrier beach system are shownin [4]. The beach does not stop at the water’s edge, butextends offshore to include sediments in the nearshore zoneaffected by wave action. The nearshore bottom may berelatively flat and smooth, may consist of sand ripples, ormay be marked by the presence of one or more submerged

sandbars. Theforeshore,or beachface, isthesteepersectionof thebeachalong thewater’sedge

between the high tide and low tide lines. This is the sectionof the beach affected by the uprush and backrush of waves.The slope of the beach face depends on grain size and waveenergy. Steeper beaches are characterized by larger grainsizes and larger waves. The berm crest is the highest point,and usually marks the normal limit of tidal action and waveuprush. Though usually linear, the waterline can consist ofa series of scallop-like ridges and depressions at regular

intervals. These features—beach cusps—form in responseto wave action. On occasion, nearly vertical cliffs—scarps—are cut into the beach face, where the sand elevation dropsfrom several inches to several feet. These are erosionalfeatures that form during storms or heavy surf. [5]

The berm, or backshore, is the dry part of the beachused mostly for recreational purposes. This flat sandy areais ideal for sunbathers, since under normal circumstancesit is generally not subject to wave and tide action.

The landward margin of the backshore is marked bysand dunes. These ridges—or mounds of loose, dry,windblown sand—are protective features and also serve as

reservoirs for sand.The nature and extentof dune formationdepends on prevailingwind direction andvelocity, andavailability of sand.Where there is a largesupply of sand, a high,wide dune field canform. Vegetation is alsocritical in building andstabilizing dunes. InDelaware, the nativeAmerican beachgrassis commonly found ondunes. Sea-rocket isfrequently found at

the toe of the foredune. The more protected backdune areasupports a greater variety of plants—including dusty miller,beach heather, and seaside goldenrod. [6] Scatteredthroughout the low areas are interdunal swales—wetdepressions that support a variety of wetland grasses,sedges, and rushes, as well as shrubs such as bayberryandcranberry.Vegetationtends to buildup the duneby trappingwindblownsand,whereasunvegetatedareas tendto lose sanddue to winderosion,forming low areas called blow-outs. Beachgrass is a veryhardy plant, and can tolerate the harsh environmentalconditions that commonly occur on sand dunes, such assalt spray and sand burial. However, the grass is susceptibleto destruction by pedestrian and vehicular traffic, so it isimportant not to walk or drive on the dunes.



6 The protected backdune area supports avariety of plants and animals.

4 Components of a natural barrier beach system.

5 Erosional scarps are cut into the beach faceduring storms or periods of heavy surf.

Backbarrier flats consist of low-lying sandy depositsformed by storm overwash. During storms, surges of watermove sand from the beach and dune, where it is depositedon the relatively flat area landward of the dune line. Thenewly deposited sand is at first colonized by grasses, andeventually by shrubs and trees. Native vegetation in thesethickets typically consists of bayberry, highbush blueberry,red cedar, beach plum, and poison ivy. Some low trees,such as blackjack oak and loblolly pines are also present.The trees are usually short and gnarled as a result of starkenvironmental conditions imposed by strong winds and saltspray.

Back barrier salt marshes form along the bay shorelineat the landward edge of the barrier system. The substratecan consist of sand, with mud and organic material in thesurficial layers. The low marsh, adjacent to the bay, isalternately submergent (under water) and emergent (abovewater) daily during normal high and low tides. Vegetation inthis area is adapted to twice-daily tidal inundation, and isdominated by smooth cordgrass. The high marsh, slightlyhigher in elevation and located farther away from thelagoon edge, is flooded only during spring high tides. Salthay and spike grass are dominant in this region. The upperlimit of the backbarrier marsh is usually marked by shrubsincluding marsh elder and groundsel bush.

Where backbarrier marshes are wide, it is an indicationthat a tidal inlet connecting the ocean and bay once existedat that location at some time in the past. Inlets becomemore and more shallow as sand accumulates, and they mayeventually close up entirely. No longer affected by strongtidal currents, former flood tidal shoal deposits may becomepartially emergent and colonized by marsh vegetation.

A bay or lagoon is a shallow waterbody, usually lessthan 10 feet in depth, that separates the barrier islandsystem from the mainland. The water is brackish, not fresh,but not quite as salty as the ocean. The bay bottom canconsist of sand or mud, or a mixture of both. Many types ofshellfish—such as hard-shell clams, soft-shell clams, andrazor clams—live within the sediment of the bay. Their shellmaterial is often also present in the sediment.

Geologic History andLong-Term Coastal ProcessesSea-Level Rise; Barrier Migration. The Delaware coasthas been shaped by geological processes that beganapproximately 17,000 years ago, when glaciers coveredmuch of North America. At that time, sea level was morethan 400 feet lower below its present level. Delaware’sAtlantic Ocean shoreline was located at the edge of thecontinental shelf, approximately 75 miles east of its presentlocation. [7] Delaware Bay was a narrow freshwater riverflowing across thecontinental shelf,forming a delta atthe shelf edgewhere waterdepths drop off.Although theglaciers did notcover Delaware,their location justto the north of usgreatly influencedthe climate.Delaware wasmuch colder then,much likepresent-day arcticCanada, withtundra and borealforests. These icesheets wereseveral milesthick, and theybegan to thaw asthe climatewarmed. Meltingwater raised thelevel of theocean, and water began to flood the land surface. By 11,000years ago, the shoreline had migrated landward, barrierislands formed along the outer coast, and the Delaware Bayestuary had begun to form. This inundation of the landsurface has continued over time, and evidence of previousland surfaces now covered by water can be seen at severallocations along the coast. For example, a drowned pineforest is occasionally visible at Cape Henlopen State Parkat Herring Point. [8] This forest, similar to the existingforested areas within the park, was located on dry landapproximately 200 to 300 years ago. Farther to the south,layers of marsh peat are occasionally exposed at the lowtide line at the beach near Gordon’s Pond. These marsheswere landward of the beach and dune lines several hundredyears ago. Along the Delaware Bay shoreline, off of FowlerBeach, an old marsh outcrop bayward of the beach shows



8 Remnants of a drowned pine forest at Cape Henlopen State Park.These trees grew on dry land 200-300 years ago.

7 17,000 years ago, when glacierscovered portions of Pennsylvania, NewJersey, and Long Island, New York,sea level was more than 400 feet belowits present level. Delaware’s AtlanticOcean shoreline was located at theedge of the continental shelf, 75 mileseast of where it is today.

remnants of the grid pattern typical of mosquito ditching.Ditching was likely conducted in the 1930s, when themarsh was located landward of the sandy beach.

As sea level continues to rise, the sandy beach and itsassociated coastal environments move in a landwarddirection, while also building upward. Along Delaware’socean coast, this occurs when sand from the ocean side ofthe beach is transported landward toward the bay side. Oneway that barrier systems migrate landward is by overwash,when waves carry sand from the ocean side of the barrierbeach to the bay side. [9] Most barriers experienceoverwash periodically during storms. Sand transported fromthe beach and dune is deposited on the backbarrier flat andmarsh, raising the elevation and extending barrier sandsinto the shallow waters of the lagoon. The higher areas ofthe overwash deposit are first vegetated by dune grasses.Eventually, woody shrub and scrub vegetation, such asbayberry and beach plum colonize the sandy area, followedby trees such as pines and cedar. The lower areas along thelagoon are eventually colonized by marsh grasses, includingsalt hay and smooth cordgrass. The vegetation help tostabilize the new part of the backbarrier and lagoon edge.Thus, the barrier system has “migrated” as a unit in alandward direction.

Another mechanism for sand transport for landwardbarrier island migration is via tidalinlet processes. In an active tidalinlet, flood (incoming) tidalcurrents bring sand from theocean side of the system throughthe inlet. As the current velocitydiminishes, sand is deposited inthe bay just landward of the inlet.These shoals are called flood tidalshoals (also flood tidal deltas, orinner shoals). They are usuallysubmerged at high tide, and maybe exposed or under very shallowwater at low tide. The ebb(outgoing) tide may transportsome of this sand out of the inlet

Delaware’s Shoreline Typesand Coastal FeaturesThe Delaware coast is characterized by a variety ofshoreline types, ranging from marshes along the northernparts of Delaware Bay to wide, sandy beaches and dunesalong the Atlantic Ocean. Characteristics of the shorelineare controlled by a number of factors, including source andabundance of coastal sediments, and wave energy availablefor redistribution of sand.

Delaware’s river, bay, and ocean shorelines, extendingfrom the northernmost part at the Pennsylvania border, tothe southernmost part at the Maryland border, exhibit awide range of characteristics.

Marsh Shoreline. Much of the shoreline along theDelaware River and Bay in the northern part of the stateconsists of tidal wetlands. From the northern border of thestate southward to the Wilmington area, the coastlineconsists of a narrow, generally marshy coastal zone. Thereis a sharp change in topography as this area meets therolling hills of the Piedmont Province to the west. Thisnorthernmost section of Delaware’s shoreline has beenextensively developed and filled; only small elements of theoriginal coastal environment remain. South of Wilmingtonto the Port Mahon area, the Delaware estuary shoreline ischaracterized by broad tidal marshes backing up to thelevel fields of the Coastal Plain. This section of the coast istypified by numerous tidal creeks, such as Blackbird Creekand Duck Creek and broad marsh islands, such as Kentand Kelly Island in the Bombay Hook area. [10] This typeof shoreline results from low wave energy and very smallamounts of coarse-grained sand in the nearshore zone. The

shoreline consists of marshmud banks vegetated bysalt marsh cordgrass andsalt hay. In some areas,the giant reed has takenover much of the wetlandarea.

Estuarine BarrierBeaches. The shorelinealong the central andsouthern section ofDelaware Bay, where waveenergy increases, consistsof broad coastal marshesand sandy beaches alongthe shoreline. Along the


toward the ocean. However, natural inlets are dynamicfeatures that do not naturally remain constant over time.They tend to migrate, shoal, and close; and can re-openelsewhere along the coast. Once an inlet closes, the sand inthe flood tidal shoals provides a source of sand forcontinued landward migration of the barrier system as thesea rises.

9 Sand is transported from the ocean beach landward toward thebay by overwash.

10 Marsh shoreline along Delaware Bay, Bombay Hook area.


central section of the Bay, the beaches are localized, andsurrounded by marshland. Communities such as PickeringBeach and South Bowers are examples of this shorelinetype. The beach is generally narrow, with a broad intertidalflat, exposed at low tide, and submerged at high tide. Dunesare sparse and low-lying. In some areas, such as BowersBeach, headlands comprised of coarse sand and gravel arelocated along the shoreline.Waves and currents redistributethese sediments alongshore toadjacent beaches.

Farther to the south, towardthe mouth of Delaware Bay,the beaches are wider, withrelatively high, vegetated dunes.Dimensions of the beach andthe presence of a dune fieldare a result of more abundantsediment as well as greaterwind and wave energy. In fact,although waves along the baycoast are normally smaller inheight than ocean waves, the southern portion of theDelaware Bay coast can sometimes be impacted by largeocean swell and waves, especially during storm events.Primehook Beach and Broadkill Beach are example of thesewider beaches near the mouth of Delaware Bay. [11]

Cape Henlopen Spit System. Cape Henlopen is a narrowpoint of land at the mouth of Delaware Bay, where it meetsthe Atlantic Ocean. [12] Geologic and historic evidenceshows that Cape Henlopen has been advancing northwardtoward Delaware Bay for thousands of years. Sandtransported northward by ocean waves approaching fromthe southeast has steadily moved sand to the north formingthis spit. Construction of the inner and outer stonebreakwaters in the 19th century appears to have alteredcurrents in the vicinity of the cape, causing an accelerationof growth of the spit tip. This process is continuing at thepresent time, and Cape Henlopen is one of the fewnaturally accreting beaches in Delaware. Cape Henlopencontains an abundance of sand for the formation of an

extensive dune field, wide, gently sloping beaches, a broadtidal flat, and numerous sand bars. One of the uniquefeatures found on Cape Henlopen is the Great Dune.

This landform rises to a height of 80 feet above sealevel, and is approximately 2-3 miles long. Most coastaldunes are parallel to the coast; the Great Dune isperpendicular to the Atlantic Ocean shoreline. Historicinformation indicates that the dune formed as a shore-parallel coastal dune along the Delaware Bay shoreline inthe early 19th century, where the bay met the ocean at thattime. It is believed that workers building the large stonebreakwater in Breakwater Harbor in the 1800s cut trees andvegetation, which led to formation and eventual southwardmigration of the dune. The dune is continuing its southwardmigration at rates of up to 6 feet each year over a maritimeforest. Sand at the steep southern edge is burying oak,maple, and pine trees. The eastern (seaward) edge of thedune is eroding and forms a steep bluff along the oceanshoreline. Like the eroding dune farther south at HerringPoint overlook, the eroding dune face provides sand to thelongshore transport system for continued northward growthof the Cape. Another interesting feature associated with

Cape Henlopen is the submerged sand bar,Hen and Chickens Shoal, a linear sand featureextending southeast from the tip of CapeHenlopen. Unlike the sand bars off manybeaches that run parallel to the shore, theshoal is oriented at an angle to the shoreline.It is closest to the shoreline off of the point ofCape Henlopen, where the crest of the shoalrises to within 5 feet of the water’s surface.Breaking waves are occasionally visibleon the shoal. The submerged feature trendssoutheasterly, and extends gradually fartheroffshore to the south. The shoal isapproximately 2 miles offshore of RehobothBeach, and is under 25-30 feet of water. The

origin and migration of Hen and Chickens Shoal is relatedto the interaction of flood and ebb tidal currents, and waveaction. The shoal is estimated to contain approximately100 million cubic yards of sand.

Beach-Headland Coast. Along the Ocean coast, there areseveral areas where highlands meet the shoreline. The townsof HenlopenAcres,RehobothBeach, thenorthernsection ofDewey Beach,and BethanyBeach arelocated onsuchheadlands.[13]


11 Sandy estuarine barrier beach and marsh along southernDelaware Bay at Primehook Beach.

13 Rehoboth Beach along Delaware’s AtlanticOcean coast is an example of a beach-headland coast.

12 Cape Henlopen spit, advancingnorthward towards Delaware Bay.


These areas are 10 to 20 feet above sea level, and aretopographically higher than surrounding lands to the northand south. The headlands consist of compacted sand andgravel, which are winnowed by waves and currents to formthe sandy beach. By virtue of their elevation, these areasare less susceptible to flooding and overwash than lower-lying areas, yet the immediate oceanfront may be subject toextensive wave damage and erosion during storms.

Barrier Beach/Inland Bay System. Much of the AtlanticCoast south of Rehoboth Beach consists of a barrier beachsystem. Included in this region are Delaware Seashore StatePark and Fenwick Island State Park, as well as the southernsection of Dewey Beach, Indian Beach, South Bethany, andFenwick Island. A sandy strip of land, varying in width fromseveral hundred to several thousand feet, separates theocean from the Inland Bays (Rehoboth Bay, Indian River

Bay, LittleAssawomanBay). Thebarrier beachon the oceanside isexposed tothe waves andtides of theAtlantic, andreflects thesehigh-energyenvironments.The sandybeaches arewide (usually100 to 150

feet from dune to water), with a fairly steep beach face as aresult of relatively coarse grain size and larger wave forces.The dunes form a continuous well-vegetated ridge that rises15 to 20 feet above sea level. The backbarrier area consistsof flat, sandy overwash deposits. Native vegetation in thesethickets typically consists of shrub/scrub vegetation,including bayberry, highbush blueberry, red cedar, andbeach plum, with some low blackjack oak and loblollypines also present. This area is visible to the east of Route 1in undisturbed areas, such as Delaware Seashore State Parkand Fenwick Island State Park. [14] Back barrier saltmarshes form along the bay shoreline. Typical vegetationconsists of high tide bush, salt hay and, closer to the water’sedge, smooth cordgrass. The backbarrier marshes arenarrow (several hundred feet) just south of Dewey Beach,and increase in width to over 3,000 feet in the vicinity ofLittle Reedy Island and Little Bacon Island, adjacent toRehoboth Bay north of Indian River Inlet. This arearepresents a former inlet which connected Rehoboth Bayand the Atlantic Ocean several hundred years ago.

Barrier beach shorelines are easily overtopped incoastal storms and, historically, temporary inlets have beencommon. During the flooding (rising/incoming) tide, ocean

waters and sediments are carried into the bays and aredeposited to form sand bars known as flood tidal deltas,flood tidal shoals, or inner shoals. These features aresometime emergent at low tide. During an ebbing (falling/outgoing) tide, water and sediments are flushed out of thelagoon and are deposited offshore as sand bars, called ebbtidal deltas or outer shoals. Waves often break over theseshallow areas in the ocean. Today, Indian River Inlet is theonly active tidal inlet along Delaware’s Atlantic coast.However, several other inlets that were open in the 17thand 18th centuries, but no longer exist today, have beendocumented in other areas along the Delaware coast.

Shoreline Processesand Sediment TransportThe shoreline and associated coastal environments areshaped by daily processes of wind, waves, tides, andcurrents. These forces constantly change, from season toseason, day to day, even hour to hour. A calm day at thebeach can suddenly turn stormy as winds kick up,generating large, choppy waves and strong currents.A storm can result in tremendous volumes of sandmovement in just a few hours.

Winds. In coastal areas, winds are important in generatingwaves and currents. Winds are the most common disturbingforce acting on the ocean surface, and they cause most ofthe ocean waves. Winds are highly variable and cangenerate small ripples or large waves. The largest wind-generated waves are caused by storms at sea.

In coastal Delaware, the prevailing (most frequentlyoccurring) winds vary seasonally. Northwesterly winds(blowing from the northwest ) are most common during thewinter months, whereas southwesterly winds are mostcommon during the summer. Variable winds occur in springand fall. There is often a daily variation in wind direction atthe beach, with onshore breezes (blowing from the seatowards land) during part of the day and offshore breezes(from land to sea) at other times. Highest velocity winds(dominant winds) tend to blow from the northeast, and areassociated with the passage of storms.

Waves. Wave action is the main force moving sediment onthe beach. Waves represent the transfer of energy across thewater surface, and not actual motion of the water. Waves inDelaware are primarily the result of wind blowing overwater. They are also generated by catastrophic events thatdisturb the sea floor, such as earthquakes, volcaniceruptions, and submarine landslides or avalanches, butthese types of waves rarely occur in Delaware. Wave terminology is shown in [15]. The highest part of awave is the crest, and the lowest part is the trough. Thevertical distance from crest to trough is the wave height.Half of the wave height, from still water level to crest, isoften called the wave amplitude. The horizontal distancebetween two successive wave crests is the wave length.Wave period is the time, in seconds, it takes a wave to


14 Barrier Beach/Inland Bay system atDelaware Seashore State Park (south ofDewey Beach). The barrier lies between theAtlantic Ocean and Rehoboth Bay.


travel its own length. This is the same as the time it takesfor two successive crests to pass a fixed point.

Wave dimensions are determined by the wind velocity,duration of time the wind blows, the distance of water overwhich the wind blows (called the fetch), and, as the wavenears the shore, the water depth. Generally, strong windsblowing for several days over a long fetch produce largerwaves. As waves travel away from where they were formed,they move across the ocean in groups. This is why we cansee ocean waves reaching the shoreline during a perfectlycalm day.

As ocean waves approach shallower water near theshore, friction with the sea floor slows the wave’s velocity.The distance between wave crests decreases, and wavesbegin to peak. As the waves continue their approach towardthe shoreline, friction with the bottom continues to slow thevelocity of the bottom of the wave, while the top (crest) ofthe wave continues its forward motion. [16] The net resultis instability of the wave, as the wave breaks. Waves tend tobreak when wave height is approximately 0.78 times thewater depth. Thus, a 5-foot wave will break where the waterdepth is 6.4 feet, and a 7.8-foot wave will break in an areawhere the water depth is 10 feet. Much of the Delawareshoreline is protected against huge breaking waves due todepth limitations and the presence of large offshore sandshoals. For example, a 30-foot high wave (which couldoccur in deeper ocean waters off the Delaware coast) wouldbreak in 38 feet of water. This depth occurs anywhere from1,000 to 6,000 yards offshore.

Breaking waves in Delaware are generally plungingbreakers, in which the front of the wave develops a curl,

due to the moderately steep slope of the beach face. [17]When the slope of the beach is gentler, spilling breakersoccur. These waves spill down their face from top to bottomas they approach the shoreline.

Tides. The twice-daily rhythmic rise and fall of the sea iscalled the tide. The average vertical distance between anormal low tide anda normal high tide isknown as the meantide range. Meantide ranges inDelaware areapproximately 4 feetalong the AtlanticCoast, 4-6 feet alongDelaware Bay, and2 feet or less in theInland Bays. TheDelaware coastexperiences two tidalcycles per day ofapproximately equalheights (semi-diurnal). Each day’stwo high tides (and two low tides) are approximately 50minutes later than those of the previous day. For example, ifa high tide occurs at 10:00 a.m. on a Saturday morning,Sunday morning’s high tide will occur at 10:50 a.m.

Tides play an important role in beach development andcoastal processes, because they constantly change thedepth of water in which waves approach the coastline andstrike the beach. The twice-daily rise and fall of water levelunder the influence of tides submerge or expose parts ofDelaware’s beaches every 6.5 hours. Tides are alsoimportant in controlling the horizontal extent of the beachand the types of plants and animals that inhabit it.

The gravitational attractions of the sun and moon onthe ocean’s waters cause tides. Because it is closer to theEarth, the moon is the more important force in producingtides. The gravitational attraction of the moon raises bulgesof water both on the side of the earth facing the moon andthe side of the earth opposite the moon. The moon revolvesaround the earth every 28 days. When both the moon’s andthe sun’s gravitational forces are in line, spring tides result.During spring tides, which occur every 2 weeks around newand full moon stages, the water level rises higher and fallslower than usual. This larger tide range, approximately 20%greater than mean tide, lasts approximately 3 days. Whenthe moon is in the first or last quarter, at right angles to thesun, lower tides, called neap tides, result. During neap tideconditions, the range is approximately 10–30% less thanaverage.

The tide level is also affected by wind conditions.Strong offshore winds (blowing from the westerly quadrants,from land to sea) push water away from the land surface,and result in lower-than-normal tides. This is especially


17 A plunging breaker.

15 Wave terminology.

16 Waves tend to break when wave height (h) is approximately0.78 times the water depth (d).


noticeable along the Delaware Bay shoreline, and in theInland Bays. Strong onshore winds (blowing from water toland) tend to cause water to “pile up” along the shoreline,resulting in higher-than-normal tides.

Associated with the vertical rise and fall in water levelare horizontal motions of the ocean known as tidal currents.Ebb tidal currents result from falling tides, when watermoves out of inlets and bays. Flood currents occur on risingtides when water flows into inlets and bays. Tidal currentsare important ininlets, the InlandBays, and DelawareBay, but haverelatively littleinfluence on theopen ocean coast.

Cross-ShoreTransport. Theshape of the beachvaries daily andseasonally, andoften changes overthe long-term assand moves onshoreand offshore. Thisprocess of sandmovement perpendicular to theshoreline is called cross-shore transport.It is important to realize that the beachis actually a 3-dimensional system, andsand is also moving alongshore, parallelto the shoreline, as described in asubsequent section.

A cross-section (profile) of thebeach is shown in [18]. The beachconsists of an emergent (dry) section,called the berm, and a submergedsection, below the water level, but stillaffected by waves and currents. Duringfair weather and low wave energyconditions,typically in thesummer months,the beach abovelow tide buildsup, and becomeshigh and wide.This occurs aslow height wavespick up sandand move it in alandwarddirection. In thewinter months,when highenergy storm

wave conditions prevail, large waves move sand from thebeach to the offshore zone, forming one or more submergedsand bars. Thus, the visible beach becomes narrower whilethe submerged supply of sand is increased. The presence ofa submerged offshore sand bar also causes waves to breakfarther from the beach. This sand is stored in the offshorebar until the cycle is repeated. During the summer months,the beach is usually wide enough to accommodate themany people who enjoy sunbathing, strolling, fishing,

building sandcastles, andcollecting seashells. [19]The same beach during wintermonths is narrower, with thewater line near the boardwalk.[20] Many people who visit thebeach in the summer becomealarmed when they see thenarrow beach in winter, butshould understand that the sandis usually offshore, and willnormally return the followingspring.

Rip Currents. Rip currents arechannelized currents of water

flowing away fromshore at surf beaches.They typically extendfrom near the water’sedge, through the surfzone, and past theline of breakingwaves. Rip currentsare important inseaward sedimenttransport. Oftenincorrectly called riptides, they are notcaused by tides.The primary drivingforce generating rip

currents is the nearshore circulationpattern resulting from wave forces.As waves transport water toward theshoreline, water returning to the seacan form channelized currents, whichtransport water (and sand) offshore.Rip currents most typically form at lowspots or breaks in offshore sandbarswhen seaward flowing water is confinedto these narrow breaks. They also mayform near structures such as groins,jetties, and piers which may deflectwater seaward. The location of ripcurrents can be recognized by a narrowchannel of choppy, churning water; adifference in water color; a break in


18 Beach profile showing emergent and submerged portions of thebeach.

19 Bethany Beach during calm conditions, when onshoretransport of sand results in a wider beach.

20 Bethany Beach during high wave energy conditions, whenoffshore transport of sand results in a narrower beach.


incoming waves; or a line of foam, seaweed, or debrismoving offshore. [21] Rip currents are a major threat toswimmers, and account for 80% of surf zone rescues bylifeguards. Average rip current velocities are 2 to 3 feet persecond. Rip currents are most dangerous during high surfconditions, when outgoing currents can reach speeds up to8 feet per second. If caught in a rip current, try to escapethe current by swimming parallel to the shoreline. Once youfeel the current diminishing, swim toward the shoreline atan angle.

Longshore Transport. Thisterm refers to the movement ofwater and sand parallel to theshoreline. This movement ofsand can be compared to aconveyor belt, in that sand ismoved from one portion of thebeach to another, and isreplaced by sand from nearbyareas. Longshore transportresults from currents generatedwhen waves strike the beachat an angle. [22] This sets upa current along the beach inthe direction that the wavesare breaking. Swimmers oftennotice this current when theyare in the surf zone and slowly drift down the beach.Unlike rip currents, longshore currents generally do notpose a threat to swimmers, as velocity is relatively slow,and they usually occur in shallow water near the shoreline. The direction of longshore transport varies as thedirection of incoming waves varies. When waves approachDelaware’s Atlantic coast from the southeast (from the rightas you are standing on the shore looking out to the ocean),the sand will move northward (to your left). When wavesapproach from the northeast (from the left as you arestanding on the shore looking out to the ocean), the sandwill move southward (to your right). Just as the directionof incoming waves can vary from day to day, so does thedirection of longshore transport.

The volume of material moved by longshore transportis related to the size and velocity of incoming waves, andthe angle at which they approach the shoreline. If wavesapproach straight toward the beach, there is no wave-generated longshore transport. The maximum transportoccurs when waves approach the coast at a 45o angle,although this rarely occurs in nature, due to waverefraction. As may be expected, larger waves can generatea stronger longshore current, and therefore can transportgreater amounts of sand. Thus, longshore transport volumesalong the Atlantic Ocean Coast are much greater than thosealong Delaware Bay or the Inland Bays.

Along most sections of the coast, waves approach thecoast more frequently from one direction than another.Along much of Delaware’s Atlantic coast, waves most oftenapproach from the southeast, setting up northwardlongshore sediment transport. Sand moves northward alongthe coastline, and is ultimately deposited at the sand spit,Cape Henlopen, causing it to grow in a northerly direction.Calculations show that approximately 200,000 cubic yardsof sand reach Cape Henlopen every year. This is theequivalent of over fifty dumptruck loads per day, eachcarrying an average load of 10 cubic yards. The totalvolume of material moving past a given point in a givenyear, regardless of direction, is called the gross longshore

transport. It is the sum ofnorthward and southwardmoving material. It is estimatedthat as much as one millioncubic yards of sediment passesalong the shoreline at FenwickIsland. This is equivalent toapproximately 100,000dumptruck loads of sedimentper year. Indian River Inlet, stabilizedby jetties, results in aninterruption of the northwardlongshore sediment transportalong Delaware’s Atlantic coast.Sand accumulates at the southside of the southern jetty,causing a wide beach to form.

In the past, very little sand reached the beaches on thenorth side of the inlet, so that the north beach eroded.The pattern of sand accumulation and erosion is just theopposite at the Ocean City Inlet in Maryland. Here, sandis moving in a net southerly direction, and accumulates onthe north side of the north jetty at Ocean City, building awide beach, whereas Assateague Island, south of the inlet,is eroding rapidly. In an area along the coast somewherebetween South Bethany and Fenwick Island, Delaware,the net direction of longshore transport diverges. This iscalled the nodal zone, north of which there is net northwardsand movement, and south of which there is southerlysand movement.


21 Rip currents can be identified in this photograph as the sandy-colored water moving past the surf zone out to sea.

22 Waves approaching the beach at an angle generate alongshore current that transports sand parallel to thebeach.


Coastal Storms. Delaware’s beaches are affected by twotypes of coastal storms: tropical systems and northeasters.[23] Tropical systems may originate in the warm waters ofthe Atlantic Ocean, Caribbean Sea, or Gulf of Mexico. Thesestorms are characterized by extremely low pressure, heavyrainfall, and high wind velocities. A tropical storm withwinds of 74 MPH or more is called a hurricane. Tropicalstorms usually occur from June through November.Northeasters (also called extratropical storms, because theydevelop “outside” of the tropics) generallyresult from one or more low pressuresystems off the coast, in which the windsblow from the northeast. While usuallylower in velocity, wind speeds can exceedthose of a hurricane. Northeasters can beaccompanied by rain or snow, and in rarecases, there is no precipitation at all.Although they may occur at any time of year,most destructive northeast storms occurduring the winter and spring months.

Although their origins differ, tropicalsystems and northeasters share manycharacteristics, and their impacts on thecoast can be similar. Both types of stormsare accompanied by strong winds, highwaves, and high storm tides. Windcirculation is in a counter-clockwisedirection around the center. The greatestdamage usually occurs in the northeastern quadrant of thestorm. Damage from strong winds is often extensive. High

velocity windscan blowshingles off ofroofs and knockdown trees andpower lines.Large objectscan be liftedand hurledthrough theair, acting asbattering ramsand causingadditionaldestruction.High wavesand tides resultin extensiveflooding oflow-lyingcoastal areas. Coastalstorms alsocause extensivebeach and dune

erosion, which results in scarping of the dunes, narrowingof the beach, or overwashing. Under normal wave

conditions, the berm is wide, with a high dune crest. Theberm is above the influence of waves and tides, and wavesbreak on the sloping intertidal beach face. [24] During theinitial stages of a storm, higher than normal tides flood theberm, and waves break at the base of the dune line. Thisoften results in formation of a near-vertical erosional scarp.Sand is eroded from the beach and deposited offshore,flattening the beach profile. The net result of storm erosionis a narrower, flatter beach; and scarping of the dune face.

Sand eroded from theseareas is depositedoffshore in the form ofone or more submergedsand bars. In extremecases, the dune isovertopped or breached,with sand transportedlandward by overwashsurges. The return ofnormal low energy waveconditions following thestorm eventually movesthis sand back on thebeach in the form of arepair bar. This ridge ofsand gradually moveslandward as a result ofwave action. During this

process, there is often a low area filled with water, called arunnel, landward of the repair bar. Ultimately, the repair barwelds onto the berm. Although the beach usually regains itspre-storm shape, some of the sand eroded by storm wavesmay be lost from the active beach system.

Large storms can cause extensive erosion resulting notonly in scarping of dunes but possible overwash of thebeach and dune system. When these storms occur, sanderoded from the beach can be carried landward by surgingwater. The sand and water may wash over or break throughthe dunes, and spill out onto the landward side of thebarrier. This deposit is usually fan shaped, and thereforeknown as an overwash (or washover) fan. Low-lying areassuch as breaks in the dune system are particularlyvulnerable to overwash. Vegetation usually colonizes theoverwash fan, and new dune growth is initiated. Thisprocess of landward movement of beach sand is consideredvital to the long-term survival of the barrier beach system.

The Ash Wednesday storm that struck the mid-AtlanticCoast on March 6-8, 1962, was one of the most devastatingin Delaware history. This was not a hurricane, but rather anortheaster, resulting from two low-pressure systems thatcombined and stalled over the U.S. East Coast. The slow-moving storm lasted through five high tide cycles over aperiod of 2.5 days. High northeasterly winds, with gusts inexcess of 70 mph, generated waves estimated to be 20-30feet in height. Maximum tide height was 5 feet abovenormal. The extraordinarily high tides and waves combinedto inflict great damage to the Delaware coast. In Rehoboth


23 Storm waves and tides along the Delaware coast.

24 Effects of storm wave attack and stormsurge on the beach and dune system.


Beach, the boardwalk and many oceanfront buildings weredestroyed. [25] The ocean washed through to RehobothBay in several locations, flattening the dunes and floodingthe highway (Route 1). When the storm receded, 4-6 feet of

On January 4,1992, an intensenortheast stormmoved acrossDelaware. Thestorm occurredduring the newmoon (springtide), when tidesare higher than

normal. Wind velocity of nearly 50 mph (as recorded atIndian River Coast Guard Station) generated 20-foot wavesoff of the coast. A maximum tide height of over 9 feet wasrecorded at Breakwater Harbor in Lewes. Although the

storm lasted onlyone day (one hightide cycle), therewas extensiveflooding in low-lying coastalareas. Boardwalksat the north endof RehobothBeach andBethany Beachwere damaged.Dune breachingand overwashoccurred inseveral locations

Broadkill Beach, Primehook Beach, Slaughter Beach, BigStone Beach, and South Bowers.

Six years later, back-to-back northeasters occurred onJanuary 27-29 and February 4-6, 1998. Tide height atBreakwater Harbor was the third highest of record onJanuary 28, just below the record set in March 1962,and the second highest tide level in January 1992. Duneerosion, breaching, and overwash occurred along theAtlantic coast from Fenwick Island to Cape Henlopen.The main road along South Bethany was damaged, and thenorth end of the boardwalk at Rehoboth Beach was brokenapart by surging tides and breaking waves. There wassignificant beach erosion along most of Delaware’s Atlanticshoreline, and much structural damage in the community ofNorth Shores, just north of Rehoboth Beach. [29] There wasextensive flooding and overwash along Delaware Baycommunities,including BigStone Beach andSouth Bowers.

Coastal Erosion.Most beachgoersare accustomedto seeing a nice,wide sandy beachwhen they visitthe coast on hotsummerweekends. Thereis plenty of roomfor beach chairs,blankets, umbrellas, coolers and all the beach gear familiesand groups of friends typically bring to the beach. Somepeople enjoy being as close to the water’s edge as possible,to take advantage of the cool ocean breezes and to take aquick dip in the ocean without having to walk too far.Others prefer being closer to the boardwalk, perhapssheltered from the ocean breeze, and a few steps closer tothe many shops. There is room for all, and all can beaccommodated. When some of these visitors return to thecoast for a winter weekend getaway and first see the beach,they may be shocked at the narrow width, and to see thetide come up to, and even in some cases, under the

boardwalk. This is whatmost people perceive asbeach erosion. However,the sand has not beenlost from the beachsystem, it has simplymoved from the dry(emergent) beach,offshore to thesubmerged (underwater)section of the beach.This seasonal exchangeof sand from the berm to



25 Destruction of Rehoboth Beachboardwalk and oceanfront buildingsas a result of the March 1962northeast storm.

26 Sand on Route 1 as a result of floodingand overwash deposition, March 1962storm.

27 Damage at Dewey Beach, January 1992northeast storm.

29 Damage at Broadkill Beach,1998 northeast storm.

28 Damage to Bethany Beach boardwalk,January 1992 northeast storm.

sand covered theroad [26].Damage to publicand privateproperty exceeded$70,000,000.

along the Atlantic coast, including Bethany Beach, DeweyBeach [27 and 28] and north of Indian River Inlet, wherethe road was closed due to flooding and sandaccumulation. Overwash and dune breaches were noted in

the submergedbar is a naturalseasonal cycle.The sandy beachthat everyoneenjoys so muchwill slowly buildup again duringthe spring months.[30] Many people

think of beacherosion aslandwardmovement ofthe shoreline.However, innature, thelocation of theshorelinefluctuates onseveral timescales. Theposition of theshoreline canchange 50 feet

or more over a single 6-hour tidal cycle, due to the riseand fall of the tide on a gently-sloping beach. There can bea 100-foot or greater seasonal change in the position of theshoreline from summer to winter, as sand moves onshoreand offshore in response to changes in wave conditions.During storms, the location of the shoreline (as well as thedune line) can move dramatically landward in a period ofhours to days. Over the long-term (centuries to millennia),sea-level rise results in encroachment of the sea onto theland.

Coastal erosion occurs when there is a net loss of sandfrom the beach system. The loss may be temporary, or itmay be permanent. An understanding of sediment sources,pathways, and sinks is necessary to determine if there is anet loss (or gain) of sand from the system.

Shoreline ChangesAlong the Delaware CoastDelaware shoreline changes over the past two centurieshave been documented using a variety of techniques anddatabases. Shoreline positions in the 19th century weredepicted on historical surveys, maps and charts. Startingin the 1930s, aerial photographs were used to identifyshoreline locations. Beach profiles, showing the beach incross-section, can be compared to document changes overtime. However, caution must be exercised with each ofthese methods to avoid misinterpretation. For example,accuracy of early documents must be established to drawquantitative conclusions. Factors such as tide stage, season,and recent storm activity should be taken into account in

interpretation of aerial photographs. Impacts of nearbystructures and placement of beach fill must also beconsidered when analyzing beach profile changes. Daily orseasonal fluctuations in shoreline position can be orders ofmagnitude greater than long-term changes. Long-termtrends may be masked by extreme events.

Atlantic Coast. By utilizing a variety of databases (historicmaps and charts dating from the 1850s; aerial photographs,and beach profiles from 1964 through 1993), the U.S. ArmyCorps of Engineers has documented that the Atlantic Oceancoast of Delaware from Cape Henlopen to Fenwick Islandhas a history of net erosion ranging from an average of oneto five feet per year. The south side of Indian River Inlet hasa long-term accretion rate of 2 feet per year, due in part tothe presence of jetties interrupting the net northerly long-shore sand transport. There is a range of coastal change,with each area going through short-term periods of erosionand accretion, with only the area north of Indian River Inletundergoing continuous erosion over the long term.

Cape Henlopen. The sand spit Cape Henlopen is one ofthe few naturally accreting beaches along the DelawareCoast. The spit is accumulating approximately 200,000cubic yards of sand each year, a result of northwardtransport of sand from beaches to the south. This hasresulted in the spit advancing over 6,000 feet northwardinto Delaware Bay during the past two centuries.

The location of Cape Henlopen Lighthouse, constructedon the Atlantic Coast of Cape Henlopen, provides anaccurate reference point to document shoreline change.The earliest accurate source of information pertaining toshoreline position along the Atlantic Coast of CapeHenlopen is based in a 1765 survey prepared in connectionwith construction of the Cape Henlopen Lighthouse.At the time of its construction in 1765, the structure wasapproximately 1,600 feet from the ocean coastline. Thestructure collapsed into the sea in 1926, so that means ittook 161 years for the sea to encroach 1,600 feet, at anaverage long-term rate of nearly 10 feet per year. [31]

Delaware Bay. Shoreline changes along Delaware Bayfrom the mid-1800s to the late 20th century have beendocumented from historic maps and aerial photographs.Highest rates of shoreline retreat (in some cases, more than17 feet per year) tend to occur along marsh shorelines suchas Kelly Island and Port Mahon in the northern section ofDelaware Bay. Lower erosion rates (less than 5 feet peryear) occurred along the central section of the baycharacterized by narrow, low-lying sandy beaches. Thesouthern section, with wider and higher beaches, erodedless than 2 feet per year. These rates, like those along theocean coast, are highly variable over time. Some areasexhibited accretion over shorter time frames.


30 The post-storm beach at SouthBethany, showing a sand ridge (repairbar) that moves onshore to rebuild thebeach after storm erosion.


Sediment Sources, Pathways,and SinksThe sand that forms our beaches is a limited resource.To develop a sound management plan for this resource,it is important to understand where the sand comes from(sources), how it moves (pathways), and where it ends up(sinks). This knowledge will help planners and managers tomaximize sand available for Delaware’s coast to ensure thatwide, sandy beaches will be available to fulfill recreational,property protection, and habitat needs.

Sediment Sources. Sand that comprises a beach issupplied by one or more sources. In some parts of thecountry, such as California, rivers transport a vast quantityof sand directly to the coastline, where it is reworked bywave action. In other areas, such as New England, waveerosion of large-scale glacial deposits provides a sandsupply to the beaches. At the present time, there does notappear to be a large amount of river-borne sedimentreaching the Delaware coast. There are localizedsedimentary headlands(such as Bowers Beachalong Delaware Bay), whichcontribute sand to thebeach system. In mostcases, though, theimmediate source of sandforming our beaches isoften an adjacent beach.Longshore currents movingsand parallel to theshoreline feed one beachat the expense of another.For example, sand movingnorthward along DeweyBeach eventually passes onto Rehoboth Beach. If thevolume of sand reachingthe beach from updriftsources is equal to the

volume continuing downdrift,there will be no perceptiblechange (erosion nor accretion)in the beach as the sand willcontinue its northward journey.If there is a structure (such as agroin) in place to trap the sand,the beach will become wider.During storms, the dunebecomes a source of sand to thebeach as storm waves and tidesattack the foredune and movesand onto the beach. Nearshoresediments, such as sand bars,can also provide sand to thebeach, but this is simply anexchange of sand. In contrast,

ebb tidal shoals associated with former tidal inlets mayprovide new sediment to the beach. For example, the oldBroadkill Inlet at Broadkill Beach closed in the mid-1900s.The sand shoals that formed in Delaware Bay off of theinlet may contribute sand to the beach at Broadkill. Overthe long term, sand in the landward sections of the coastalbarrier, such as washover deposits and flood tidal shoals,supply sand for continued barrier island migration inresponse to sea level rise. Since the 1950s, renourishmenthas provided an additional source of new sand to many ofDelaware’s beaches. Sand, either trucked from inlandsources, or pumped hydraulically from underwater sources,represents a net input of sediment into the beach system.

Sediment Pathways. The beach is a 3-dimensionalsystem—with sand moving onshore, offshore, alongshore,and upward over time, as described in previous sections.These pathways transfer sand from its source to its finaldestination. [32]

Sediment Sinks. Sand can be lost from the beach systemto a variety of sinks. Some of these sinksare temporary, others more or lesspermanent. Sand transported offshore asa result of seasonal cross-shore transportmay be viewed as a temporary loss, asmuch of the sand returns to the emergentbeach in a matter of months. Similarly,much of the sand lost from the beach tothe offshore by storms also finds its wayshoreward during post-storm recovery ofthe beach. However, there may be somenet offshore loss of sand from a majorstorm, if the sand is transported so farseaward, into deep enough water, that“normal” wave action cannot return thesand to the beach. Storms also causelandward transport of beach sediment byoverwash. Sand is lost from the beach asit is deposited on the backbarrier flats andat the edge of the lagoon. Eventually, this


31★★★

Aerial photographs of Cape Henlopen from 1926, 1968, and 1997 showing northward progradationof the spit. The red star marks the location of the 1765 Cape Henlopen Lighthouse, which fell intothe sea in 1926.

32 Sediment sources, sediment pathways, andsediment sinks.


sand will be incorporated back into the beach system(hundreds or even thousands of years from now) as sealevel rises.

The spit Cape Henlopen represents a significantsediment sink in Delaware. It is estimated that the spit isaccumulating 200,000 cubicyards of sediment each year,derived from northwardtransport of sand frombeaches along our Atlanticcoast. Most of the sandis contributing to thenorthward growth of theCape. [33] However,a small volume of sand iscontinually moved offshoreby ebb tidal currents to formHen and Chickens Shoal.

Inlet processes alsoresult in a net loss of sandfrom adjacent beaches. Ebb tidal currents move sand fromthe beach offshore, to form ebb tidal shoals. It is estimatedthat the ebb tidal shoal in the Atlantic Ocean off of IndianRiver Inlet contains up to 8 million cubic yards of sand.In contrast, flood tidal currents move sand from the beachinto the inlet, and result in deposition of the sand in theform of flood tidal shoals in the lagoon. Like overwashsands, flood tidal shoals will eventually become long-termsources of sediment for barrier migration as sea level rises.

Human Impactson Natural Beach SystemsA natural barrier beach system consists of a number ofinterrelated environments (beach, dune, backbarrier flats,and salt marsh), each created by and adapted to thephysical forces that affect it. The physical shape of eachzone and the vegetation that stabilizes it are dependentupon elevation relative to sea level, distance from the sea,availability of sediment, amount of salt exposure, andfrequency of overwash. The system and its componentsadapt to the continuing natural stresses and forces. Theresult is that over time, the entire system maintains itself.A natural barrier beach system [34] has a wide, gentlysloping beach berm, a low natural dune system, vegetatedbackbarrier flats, and a low-lying backbarrier marsh alongthe lagoon shoreline. During storms, waves and tidesovertop the beach and dune system, and overwashdeposition occurs on the backbarrier, where sand isdeposited to build the barrier upward and landward.The newly deposited sand is then colonized and stabilizedby vegetation.

In contrast, an artificially stabilized barrier beachsystem, one that has been altered by human intervention,assumes a different shape than a natural system.Stabilization of dunes and beaches is often necessary toprotect developed areas that could be damaged by

flooding and storm overwash. Dune stabilization usuallyinvolves placing additional sand to form a continuous,high ridge to prevent flooding on the landward side. Otherimpacts of development on a barrier system may includeconstruction of roadways and houses on the backbarrier;

placement of fill material on thebackbarrier marsh; and constructionof bulkheading along the lagoon edge.These activities may have an adverseeffect on the long-term maintenanceof the barrier system by inhibitingor preventing overwash deposition.Artificially stabilized dunes are usuallyhigher and steeper than low, naturaldunes. Instead of being transferredlandward by overwash during stormevents, sand is transported offshoreand alongshore. Any overwash thatdoes occur is often removed fromroadways and residential areas, and

lost from the system. Ultimately, the elevation and widthof the barrier system will not maintain itself as sea levelrises.

Survival of structures built along our barrier beachesdepends upon maintenance of the beach and dune system.Although storms and sea-level rise are causing the shorelineto move landward, prudent management of beachfrontdevelopment and wise engineering practices can minimizethe adverse effects of these changes to the natural system.

SummaryThe components of the barrier beach system are allinterrelated. Their dimensions, and thus their use forrecreation, property protection, and habitat value, aredependent upon the physical forces affecting them. Theamount of sand available to the system is limited; thereforeit is important to understand sediment sources, pathways,and sinks for regional sediment management purposes.This enables coastal planers and managers to maximizeand make the best use of this important resource. ■


33 Cape Henlopen spit—end of the conveyor belt ofsand.

34 Comparison of natural and artificially stabilized barrierbeach systems.


TThe Beach as a

Natural Resource

While many residents and visitors appreciate Delaware’sbeaches for their obvious recreational value, the importantfunctions of the beach as a natural environmental resourceare sometimes overlooked. Beaches have been too oftenviewed as a part of an urbanized coastal landscape thatvisitors seek for their recreational time. Beaches are naturallandforms that support a wide variety of plants andanimals, including people. [35] The sandy beach and duneareas provide unique habitat for a number of plants andanimals that have adapted to the stressful environmentfound along Delaware’s Atlantic coastline.

Beach managers and the government entities thatprovide funding for competing demands for natural resourcemanagement must look at the functions and values thatbeaches provide. If we break down beaches into the variouscategories of benefits they provide and their related values,it helps determine how best to manage the resource.

The many benefits of Delaware’s beaches include:

■ Biological habitats provided for beach-dependentplants and wildlife. Our beaches provide importanthabitats for native, threatened, and endangeredspecies such as the piping plover, the common ternand the least tern.

■ Storm protection and damage reduction. Physicalcoastal features such as beaches and dunesprovide a safety buffer between the ocean and ourcoastal communities, thus reducing storm damageto public infrastructure, private development, andimportant habitats.

■ Recreational, educational, and aesthetic valuesof a wide sandy beach, and access to the sea.Our coastal areas provide irreplaceable recreationaland educational opportunities. and visuallypleasing vistas. They also provide recreationalaccess to the sea for millions of residents andvisitors to the state.

■ The contribution of beaches to the local, state,and national economies. Our beaches injectmillions of dollars into the economy throughrecreation and tourism.

Biological HabitatAt first glance, the beach may seem to be an environmentbarren of living things (with the exception of shorebirds andoccasional jumping dolphins). In fact, many of the animalsthat live at the beach are so small that they may escapenotice, especially because they’re typically burrowinganimals, hidden from view most of the time. Plants andanimals that live in beach environments must be able tosurvive many physical stresses that create rather hostilesurroundings—salt spray, occasional overwash by seawater, freshwater rainfall, strong winds, shifting sands,and extreme heat and sun. Many species are specialized toa dune/beach/nearshore existence, making a beach systemthe unique environmental niche for these plants andanimals.

Plants and Animals in Ocean Beach Zones. In theturbulent surf zone where conditions are particularly harsh,relatively few species occupy the substrate in this areaof breaking waves and churning sands. [36] Beyond thesurf zone, there may be a longshore trough, sand flatand sandbar system that is covered by seawater andcharacterized by well-aerated water and stable watertemperatures. Here conditions are more favorable, anumber of animals burrow in and crawl over the bottom, orfeed close to it. Some of the animals found in the sub-tidalareas include whelks and crabs. Several different types offish such as dogfish, skates, weakfish, bluefish, and pufferfish swim in nearshore waters, often in the breaking waves.



35 The beach environment is a natural resource that providesbiological habitat for a variety of plants and animals.

36 Turbulent surf zone environment and intertidal zone.

Life in the intertidal zone (between the tides) on anocean beach is full of extreme physical stress—not onlyfrom the alternating submersion and exposure as the tidesrise and fall, but also from the turbulence of the water aswaves break and the constant movement and shifting ofthe sandy sediment. Except when exposed by the fallingtide, the sand is in almost constant motion, and animalsmust adapt by burrowing into the sand to survive. Somesand-dwellers are blind,while others havereduced eyes or eyesthat rise above the sandon long stalks. Mostsand-dwellers feed onorganic detritus trappedbetween sand grains, orfilter particles ofsuspended food fromwater passingoverhead. Many tinyanimals and plants livebetween sand grains—from microscopic organisms, to slender worms and tinycrustaceans. This unstable habitat is such a severeenvironment that no higher plants can exist here and onlya few larger animals call this turbulent area home—lugworms, the mole crab, and tiny shellfish such as thecoquina clam.

Mole crabs (or sand crabs) can be seen burrowing upand down in the surf zone as the water swashes aroundthem. [37] Their round, compact shape helps them digquickly into the sand as waves crash over their bodies.Mole crabs are a food source for shorebirds, fish and othertypes of crabs (such as the calico crab or blue crab) that livein the shallow water near the beach. The mole crab is wellknown to beachgoers, sought after by fishermen for bait,dug up by children for amusement, and eaten by othercrabs, shorebirds, and fishes. With its special adaptationsfor coping with churning water and sand, it is able toburrow and migrate up and down the beach slope with therising and falling tides.

Another animal found in the beach intertidal zone isthe coquina clam. Tiny, multi-colored coquina clams canalso be seen burrowing intothe beach slope as a wavebreaks on the beach and thewater recedes. [38] As thewater rushes back down thesandy slope to the sea,coquinas extend theirfeeding siphons and filterplankton. The coquinaseems to thrive in theshifting swash zone, andmoves up and down thebeach slope with the tide.Although it is not a swimmer

like the mole crab, the coquina clam can anchor itselfquickly and dig itself into the sand.

In contrast to the high energy surf zone of Delaware’sAtlantic coast beaches, the sandflats along Delaware’s bayshoreline are home to greater numbers of bottom-dwellingand intertidal organisms. Waves are usually smaller alongthe Delaware Bay coast, and consequently, the physicalstresses on plants are animals are not as severe. Some of

the more typical plants and animals living on thesandflats of Delaware Bay’s intertidal zoneinclude: sea-lettuce and brown algae (types ofseaweed), horseshoe crabs, mud snails, hermitcrabs, sand shrimp, and various tiny amphipods.In certain areas along the bay coast, worm reefsor dense clusters of worm tubes and nodulesconstructed by tubeworms are prevalent. Manyother types of burrowing worms live within tidalflat sediments such as plumed worms, cellophanetube worms, red-gilled mud worms, and sand-builder worms. Additionally, razor clams and hardclams are examples of bivalves that can be foundliving

below thesurface of theintertidalsandflats.

The areaabove thereach of everyday waves andtides is themost sparselypopulated ofall the beachzones. Saltspray, shifting/blowing sand, and occasional flooding by storm waves andtides are some of the physical stresses exerted on animalsliving in upper beach and foredune environments. Whileresident species may be few, there are a number of animalsthat hunt, feed and rest on the upper beach area, includingmany types of shorebirds, sparrows, grackles, red-wingedblackbirds, fish crows, raccoons, and red foxes.

Due to the dynamic nature of thebeach and the constantly shifting sands,only a limited number of plants arefound in this environment. Sea rocket isa tough plant found in the upper beachzone, with thick, fleshy leaves to helphold in water. [39] Sea rocket is oftenthe first plant to grow on a stretch ofbare sand, typically sprouting in thewrack line at the upper edge of thewinter’s highest tide reach. Sea rocketcan be found growing from the toe of thedune to the high tide line, but canquickly disappear when high tides and



39 Sea rocket—a pioneer beach plant.

38 Coquina clam.

37 Mole crab.

waves scour beach sands.Other plants that can befound growing on thenarrow upper beach stripinclude beach pea,seaside spurge, commonsaltwort, and Americanbeachgrass. American beachgrassis a good example of aplant that has developedspecialized adaptationsthat allow it to actuallythrive in the harshconditions found at thebeach. [40] Americanbeachgrass is the mostcommon type ofvegetation found along

Delaware’s sandy shores. This hardy plant is found in upperbeach and dune areas, helping to hold the sand in placewith upright green leaves and stems that deflect erosionalwind, and an extensive network of underground stems andwith roots that grow deep in search of fresh water.Beachgrass knocks down windborne sand, resulting in sandaccumulation or dune building. This specialized grassactually thrives when it is buried by sand. Living and dead plantmaterial can be found in theupper beach zone in the wrackline. The wrack line comprisesan assortment of animalfragments, organic matter, andsometimes trash transported bythe waves and deposited at thehigh tide line. The cast-updebris usually includes anaccumulation of variousseaweeds, fragments of shellsand plants carried by currentsfrom other areas, remains ofhorseshoe crabs, fish, and othermarine animals, and driftwood.[41] Beach wrack provides afood resource and furnishesshelter from drying winds andpredators. One tiny animalfound abundantly in beachwrack is the small amphipodknown as the sandhopper, sandflea, beach-hopper, or beachflea. Beach fleas are scavengers,feeding upon decaying plant and animal matter.They are eaten by many shorebirds such as sanderlingsand plovers, and are an important food source for theghost crab.

The beach is a harsh environment for most animals.In winter, storm waves pound the shore and cold windsblow sand and salt spray. In the summer, the sand can beincredibly hot and dry as a desert. However, the sandybeach is home to a few very specialized animals. The mostcommon resident animal of the upper beach and foredunearea in Delaware is the ghost crab. [42] The sandy-coloredghost crab spends most daytime hours in holes burrowedinto dry beach areas, venturing out at night to feed.The ghost crab isuniquely adapted tolife on the dry beach,and is almostimpossible to see onthe beach unless it’smoving. Even then,it’s a challenge formost beachgoers tocatch a glimpse of aghost crab—only thesharpest eyes will seethe nearly invisibleswiftly moving crabwith unmatchedburrowing ability.Ghost crabs are primarily nocturnal, but it is sometimesactive in the daytime, standing watch at the entrance of itsburrow. Their burrows are usually found on the upper

beach near the toe of the dune, but they can befound just above the high tide line. While theycan remain out of the water for long periods oftime, a ghost crab may venture into the surf towet its gills from time to time.

American beachgrass is the dominantvegetation found in Delaware’s primary coastaldunes (immediately adjacent to the beach).This grass is specially adapted to the extremeenvironmental conditions that arise fromexposure to wind, salt spray, periodic blowoutsand sand deposition, and extreme temperaturefluctuations. Temperatures at the sand’s surfacemay reach 120 degrees on a hot summer day!In more sheltered dune areas, other types ofvegetation can be found, including seasidegoldenrod, prickly pear cactus, dune sandbur,dune panic grass, joint-weed, and seasidespurge. Gradually dune vegetation may growhigher and more dense, creating a more stablearea with increased organic material whereadditional kinds of plants including shrubsand trees can grow. The shrubs and trees in theback-dune zone are often pruned to smaller

sizes by windborne salt spray. Low-lying areas betweenand behind dunes, also called interdunal swales, are oftenoccupied by wetland vegetation. However, despitecolonizing vegetation, no dunes should be considered apermanent part of the coastal landscape; the whole area is



40 American beachgrass thrivesin the dune environment.

41 Organic wrack line debris can befound at the high tide line.

42 Ghost crab.

subject to extensivechange due to powerfulwinds and churning water(waves and tidal currents)breaking through duringstorms. On very windydays, the tops of dunesmay appear to be “misty”with windblown sand andsalt spray. [43] Whenovertopped by stormy seas, the dunes serve as reservoirsof sand for the rebuilding of wave-cut beaches.

A variety of plants and animals live on the dunes, frombeachgrass and ghost crabs to hairy wolf spiders, velvetants, and digger wasps. In the spring, terns are among theshorebirds that rely on the dunes for nesting grounds.Their well-camouflaged eggs match the color of the sand.

In the fall, the yellowblossoms of seasidegoldenrod attractmonarch butterflieson their southwardmigration. [44]

Birds. Beaches areespecially importantfeeding, resting,breeding, and nestingareas for many speciesof birds and shorebirds.Perhaps the mostcommonly seen birdsalong Delaware’sbeaches are the gulls,resting in large groups,sleeping, eating, orsearching the sandfor food. Gulls areusually considered to

be scavengers of the beach, and they eatanything they can find, dead or alive.Somewhat smaller and more energeticshorebirds are often seen at the water’sedge, searching for food in the sandy slopewhere the waves rush onto shore. Thesequick-footed shorebirds may besanderlings or sandpipers, darting backand forth at the water’s edge. They probethe wet sand with their long bills, findingfood such as tiny clams or mole crabs.[45] Other shorebirds commonly seensearching for food in the wrack line or atthe upper edges of surf beaches includeruddy turnstones, black-bellied plovers,and willets.

The common tern and other tern species are alsofrequently seen at Delaware beaches, and may often beobserved diving into the ocean to catch small fish withtheir bills. Terns may look somewhat like gulls, but theyare smaller, more slender, and more graceful in appearanceand motion. Many tern species, including the royal tern,use the beach as a breeding and nesting site. They oftennest on the back part of wide, broad beaches, away fromthe water’s edge.

The sandy beach and coastal mud flats also provideimportant habitat for the American Oystercatcher, a large(chicken-sized) bird with an easily identifiable blackish-brown/white pattern and a long red bill. Oystercatcherswere named for their ability to insert their long, bladelikebills into mussels, clams, oysters and other shellfish, cuttingthe bivalves’ powerful muscles before the shells can close;they also feed on barnacles and snails. The oystercatcherwas once over hunted along the Atlantic Coast, but becausethey are now a protectedspecies, the oystercatcherpopulation has onceagain become morenumerous in coastalareas.

An endangeredspecies, the pipingplover, is a smallshorebird that also nestshigh up on the beach,away from the ocean.[46] Piping plovers areendangered, becausetheir preferred nestinghabitat—a safe, secluded beach area—is getting harder to

find. Each nesting pair of ploversfinds an isolated spot in the sandto make a nest, typically laying aclutch of 2-3 eggs. The birds andthe eggs are so well camouflaged in

the sand thatthey aresometimesdifficult to see.Upon hatching,light-coloredplover chicks areready to run andfeed in the upperbeach. However,many youngchicks are killedbefore reachingadulthood eitherby naturalpredators or byunintentionalhuman activity.



46 Piping plovers build theirnests in secluded beacharea, usually near the baseof a dune.

43 Blowing sand is trapped bygrass on dunes.

45 Beaches provide habitat for many species of shorebirds.

44 Migrating monarch butterflyon seaside goldenrod.



Ongoing Research Advances the Scienceof Beach System Resource Management

The proper management of Delaware’s beaches involves more thansimply managing sand to maintain a recreational beach. Delaware’sbeaches have multiple functions and values – from those associatedwith a recreational resource and storm protection functions to thoseassociated with environmental and habitat considerations. DNRECsponsors coastal research projects that provide coastal managerswith information needed for beach system resource management.Here are highlights of just a few:

Delaware Shorebird Monitoring Programs. Every spring andfall, the Delaware Bay shoreline plays an important part in themigration of shorebirds as they travel the thousands of milesbetween the Arctic tundra and the wetlands of South America. As animportant link in the migratory flyway, the sandy beaches and tidalwetlands of the Delaware Bay provide critical resting and feedingsites for more than 40 species of migratory shorebirds. [47]

Since 1997, the Delaware Shorebird Monitoring Team, led byDNREC’s Delaware Coastal Programs Section (DCPS), has beenconducting researchinto the populationdynamics and health ofkey shorebird species inthe Delaware Bayregion. The teamconducts shorebirdpopulation studies bycatching and releasing,counting, tagging,measuring and markingindividual shorebirds.Over time, completeand thorough records ofpopulation numbers,body size/condition, andweight gain will provideinvaluable informationon shorebird migrationand the critical feedingand resting areasprovided by DelawareBay shoreline habitats.

Horseshoe CrabHabitat Study.While beach nourishment projects are often discussed relative tocreating recreational beach and storm protection barriers, beachnourishment is also an effective management tool for habitatrestoration. DCPS recently conducted experiments to gain a betterunderstanding of the role beach nourishment can play in improvingspawning habitat for the horseshoe crab along Delaware Bayshorelines.

Horseshoe crabs can be seen along the shoreline of manyDelaware Bay beaches, especially at high tide during the monthsof April, May and June. In fact, the Delaware Bay estuary hosts thehighest concentration of spawning horseshoe crabs in the world.

During peak spawning periods, female horseshoe crabscrawl out of bay waters onto shore to lay eggs on theupper beach. [48] The eggs mature in these sands andgravels until they hatch when high tides reach themagain in four to eight weeks. Horseshoe crab eggs are an important food sourcefor fish, gulls, and migratory shorebirds. An importantconnection has been identified between the arrival ofspawning horseshoe crabs on Delaware Bay beachesand the spring migration of many species of shorebirdsthat stop at Delaware Bay to rest and feast on horseshoecrab eggs. [49] The recent decline in the horseshoecrab population has prompted concerns that thesemigratory shorebirds may not have adequate foodsources to complete their long journey to Arctic nestingareas.

The Delaware Coastal Programs Section hasconducted studies to examine specific beachcharacteristics such as grain size on the sand/gravel

48 Horseshoe crabs mating.

47 Shorebirds feasting on horseshoe crabeggs.

49 Horseshoe crab eggs are an important food sourcefor fish, gulls, and migrating shorebirds.

mixed beaches that are critical to horseshoe crab spawning habitat.The overall objective of these studies is to compare spawning levelsat nourished beaches to those that had not been nourished, and todetermine whether beach nourishment could be used as an effectivemanagement tool to restore, create, and enhance horseshoe crabspawning habitat. [50] Preliminary results show that there was anincrease in the amount of spawning activity on nourished beaches,suggesting a positive impact of beach nourishment on spawning, eggdensity, and egg development. While more research is required toassess specific beach design characteristics, this work has shownthat beach management and nourishment projects can be used toimprove horseshoe crab habitat and wildlife use. The DelawareCoastal Program plans to continue assessing beach nourishment asan opportunity for habitat restoration through the building of beacheswith sediments that are most suitable for horseshoe crab spawninghabitat.

Piping Plovers. The piping plover is designated as a threatenedspecies along the Mid-Atlantic coast, and is protected under theEndangered Species Act that provides penalties for taking, harassingor harming the plover. This small sandy-colored bird uses the beach

area as a feeding and nestinghabitat. Each spring,migrating plovers arrive inDelaware during March orApril to breed on uninhabitedbeaches, building nests in thesand near the base of thedune. The breedingpopulation of piping plovers inDelaware has ranged fromtwo to six nesting pairs eachyear since 1989, and thesenests have only been foundon state park beaches along

Delaware’s Atlantic Ocean coastline. A nesting pair usually incubatesthree to four sandy-colored eggs for four weeks until the chickshatch. [51] Plover chicks are unable to fly for their first 25-35 days,and they must travel across the beach to the water’s edge for food.



Both adults and chicks feed on small worms, crustaceans, and insectsthat are found in the wet sand or in high-tide wrack lines.

Even though young plover chicks are so well-camouflaged thatthey are likely to be undetected by beachgoers, intruders, orpredators, there are many threats to their survival. [52] Extremelyhigh storm tides can cause flooding of the back beach and dune areasthat could destroy nests and drown chicks. Predators include foxes,dogs, cats, raccoons, skunks, gulls, and fish crows.

Along the Delaware coast, increasing commercial, residential,and recreational development have reduced the habitat available forpiping plovers to nest and feed, resulting in a declining population.Although human disturbancesmay be unintentional, theyoften result in severe impactsto plover survival. Vacationersenjoying the beach may stepon or walk right past a well-camouflaged nest, disturbingadults and chicks withoutknowing it. A simple activitysuch as flying a kite in a plovernesting area may interruptfeeding, nesting, restingbehaviors that are critical forthe plovers’ growth andpreparation for their southward migration. In some areas wherevehicles are permitted on the beach, the deep tire tracks themselvesmay trap small chicks, making them more vulnerable to predators or toother vehicles.

DNREC’s Nongame and Endangered Species Program hasdeveloped management strategies for the state’s breeding populationof plovers that include: fencing off plover nesting habitat, protection ofnests with predator exclosures, and education of beach users abouthow they can protect the piping plover. Perhaps the most effectivemanagement strategy is to preserve, maintain, and protect theremaining natural beach areas in Delaware that are suitable ploverhabitat. [53] State agencies are working cooperatively to ensure thatproper beach management practices are in place to enhance ploverhabitat and avoid interference with natural processes that shape thelandscape at these sites. Similar efforts and coordination areunderway regarding DNREC policies that eliminate humandisturbance and vehicular traffic in plover nesting and foraging areasduring the breeding season.

50 Close-up view of horseshoe crab eggs and beach sediment.

52 Plover chick and eggs.

51 Plover nest on beach.

53 Plovers prefer wide isolated beaches for nesting habitat.



Storm Protectionand Damage ReductionEstuarine Protection. Another function of beaches thathas not been described very often is the protection providedby beaches to valuable coastal landforms on their leewardside. There has been muchwritten about the high valuesthat wetlands provide in terms ofboth water quality issues andbiological functions or benefits.Did you ever stop to think whatthese marshes would be like ifthey were exposed to direct waveattack? The likelihood that theywould exist at all under theduress of a full blownnortheaster is very low. Thebeach’s role as a shock absorberis a critical function to landward,quiet water habitats orlandforms. [54]

Storm Protection. The conceptof beaches as shock absorbers,described above, is not foreign to residents along beacheswho have witnessed coastal storms first hand. When thewind blows hard over the ocean it generates waves that cangrow to the height of a 3-story building. At the same time,tides can be elevated several feet above normal. Thecombination of high waves hitting the coast at the sametime that tides are running higher than normal allows thesevery large waves to get closer to the coast before they break.The waves also have a greater velocity in their forwardmovement to the coast due to their size and the highwinds pushing them; this in turn greatly imperils coastaldevelopment. The power of the waves and tides is what isso damaging to structures built along the coast. As sand ismoved across and along the shore, a wide sandy beach canabsorb the wave energy and provide a buffer between

crashing surf and developed property. During a storm event,high waves, tides, and currents reconfigure the shape of thecoast and redistribute the sand along a beach (alongshoreand cross-shore). The expenditure of wave energy used tomove sand reduces the power of waves before they impactstructures. With wave energy expended on the beach, less

damage is inflicted onadjacent coastalstructures. [55] The federal beachnourishment project inneighboring Ocean City,Maryland, providesan example. Designedto provide stormprotection, the projectinvolved constructionof a beach and dunesystem north of theboardwalk, and aseawall and sandybeach along theboardwalk. While theproject was expensiveto build and maintain

($74 million dollars for initial construction phases andrenourishments in 1992, 1994, and 1998), governmentofficials have determined that the wide beach preventedapproximately $214 million in property damage during the1992 and 1998 northeasters.

RecreationThe beach is the top destination for tourists in the UnitedStates. Each year, millions of vacationers flock to thenation’s coastline for rest, relaxation, and recreationalopportunities. [56] On a hot summer day, the high qualityexperience that comes from being near the ocean’s edgeis something sought out by millions of people each year.

54 Protective beach and tidal wetlands, Delaware Bay shoreline.

55 Waves pounding beach and eroding sand.

56 Crowded, wide recreational beach—Rehoboth.



The ritual of returning to the beach you have enjoyed in thepast, of staking out your turf/territory early each morning,being surrounded by family and friends, enjoying a seabreeze, taking a cool swim in the ocean, letting the sunbake you dry, enjoying lunch on the beach, flying a kite,digging for crabs, catching a fish, finding a seashell—theseactivities are what make people return in droves each yearto our nation’s shorelines.

Delaware, like so many other states, has seen thedevelopment of coastal communities along its beaches.The demand for a summer day at the beach by millions ofpeople has createda vital segment ofthe economy. Butfundamentally, it isthe ability of thebeach to provideadequate space forfamilies to sit bythe ocean on a hotsummer day that isone of the highestvalues of thebeach. Peopleenjoy having spaceon a beach tospread out towelsor blankets; to setup chairs; to havefamily and friendsjoin them as part oftheir recreationalday. The ability of a beach to provide ample space for theseactivities for all of those people who arrive to enjoy it onany given day in the summer is one of the functions thatbeach managers must try to continue to provide. Therehave been studies conducted about the beach space that agroup of four people might need in a day, but in general, weall have a sense of how much space we would like to haveon the beach to enjoy our beach day without being in closeproximity to the next group of people. As a beach erodes,one of the first threats to the value of a beach is the loss ofrecreational space that results in a diminished recreationalexperience for people who have sought out that beach. [57]

The investment made by beach users in driving time, travelexpenses, and lodging and meal expenses should bereflected by a high-value recreational opportunity on thebeach. Many beach communities have seen that as theirbeach diminishes in width and the recreational experiencesdiminish because of overcrowding, there follows a down-turn in the economic vitality of their community. There is adirect correlation between beach width (or beach quality)and the recreational expenditures made within acommunity. Every beach community wants to maintain itseconomic vitality and high-level recreational experience.

The beach istypically thought ofas a recreationarea—a popularvacation destinationwhere people canrelax through avariety of activitiessuch as sunbathing,swimming, reading,walking, and fishing.However, ourbeaches are muchmore than a populartarget area forvacationers.Beaches and dunesalso act as aphysical buffer tostorm winds, waves,and tides. The

beach environment provides critical habitat areas for avariety of unique animals. While all of these varied beachfunctions and values are important, an often-overlookedvalue of our sandy beaches is the role they play in thestate’s economy. In fact, the sandy beaches provide thefuel for a critical part of Delaware’s economic engine. ■

57 Narrow beach provides diminished recreational area.

Beaches are a vital part of the nation’s valuable tourismeconomy. Coastal areas are now some of the most denselypopulated and developed parts of the country. There is highdemand for residential, commercial, recreational, andenvironmental use of coastal lands.

The numbers are staggering. According to the U.S.Census Bureau, 54 percent of America’s population liveswithin 50 miles of the coast, and more people are moving tocoastal areas every day. More than 90 million Americans

and foreign tourists visitcoastal communities eachyear to enjoy a beachvacation full of food, fun,sun, surf, and sand. Infact, beaches are theUnited States’ largesttourist attraction—approximately 40% ofvacationing Americans listbeaches as their favoritevacation destination. Thetourism/travel industry isthe nation’s largestemployer, and coastalstates receive about 85% ofall tourist-related revenuesin the United States. It has

been estimated that beach tourism generates billions ofdollars of local, state, and national tax revenues.

In coastal Sussex County, tourism revenues, real estatevalues, and recreational use are largely dependent upon thequality of its beaches. Coastal residents, business owners,property owners, and visitors alike have relied on thepresence of wide, healthy beaches. Their expectations arereflected in property values and decisions to purchaseproperty, make business investments, and plan vacations atthe state’s ocean beaches.

The interaction between the shoreline and the economyin Delaware is dynamic and fragile. The coastline ofDelaware draws nearly 5 million visitors each year to swim,sunbathe and enjoy the many environmental amenitiesunique to the coastal area. [58]

These visitors bring tourism dollars to the region andthe state, representing a strong economic input to both.While visitors pay for parking, lodging, food and otherpurchases during their visits, access to public beaches isfree. The vast majority of tourism is from other states, sothe expenditures represent a true influx of dollars into anotherwise rural and correspondingly sleepy economy. While it is somewhat difficult to determine the totaleconomic benefits of our beaches, consideration of the far-reaching economic activity generated by beach tourism can

serve as an example. Tourism dollars bring lifeand jobs to the Delaware economy. In order ofimportance, tourists spend money for lodging,restaurants, entertainment, food and sundriesand transportation. Tourist spending brings onincreased economic activity with resultingbenefits and revenues to local businesses.Profits generated by these expenditures exceed$25 million and the expenditures support morethan 7,400 jobs with wages in excess of $145million. State and local taxes on these wagesexceed $23 million. These jobs represent about19% of the jobs in Sussex County, the location ofDelaware’s ocean beaches. Benefits of thistourist-based economic activity go far beyondretail businesses, affecting many citizens andfacets of thriving coastal communities. The beachtourism industry supports the general work


TThe Beach as an

Economic Resource


58 Busy beach and boardwalk in Rehoboth.

force—lifeguards, hotel and restaurant employees,entertainment activities, construction-based jobs, propertyand utility maintenance, retail businesses, real estate, andlocal government jobs.Additionally, the beachtourism industry extendsto those businesses thatattract tourists to a beachlocation—advertisementsvia radio, television,billboards, newspapers andother media. Getting peopleto the beach is anothertourist-based economicconsideration—state roadsand road maintenance, gasstations, roadside stands,convenience stores, andother such amenities andservices.

The flow of importanttourism dollars is vitallylinked to a healthycoastline. When erosionrobs the shoreline of beacharea, tourism falters. Thestate dedicates fundingresources to protecting thosebeaches to prevent the lossof tourism from erosion.In just 2 years, without thestate’s careful managementof beach areas, an estimated45,000 tourists each yearwould choose otherdestinations. After just 10 years, more than 2 million visitorswould stop visiting Delaware’s beaches, devastating thelocal economies and seriously damaging the state’seconomy.



Understanding and quantifying the functions orservices that beaches provide is an essential first step forbeach managers in determining if management actions are

needed to protect thosefunctions. The next stepwould be to determineboth the cost of taking amanagement action, as wellas the cost of not taking anaction and allowing timeand erosion to continue.Assigning values to thefunctions of beaches is theway that managers candetermine the return fortheir managementexpenditures. If the valueto society at large of aparticular beach functioncan be determined, thenappropriate levels of fundingfor protection of thosevalues can be determined.This is commonly done ineconomic analysis of thenatural resource. Fundingfor beach protection iscompeting in state andfederal budgets with manyother needs, and in almostall cases, the decision ofwhether of not to nourish abeach is based on both costbenefit analysis andpolitical will. The full

functions and values of beaches as a natural resourcewith high societal value must be taken into considerationto determine the best way to manage the resource as wellas the appropriate amount to spend to protect or enhancethat resource. ■

HEvolution of a Beach Management Program. Geologicallyspeaking, it has not always been necessary to have a beachmanagement strategy for Delaware’s coastline. For thepast 10,000 years, our shoreline and associated coastalenvironments have evolved under the influence of sea-levelrise, coastal storms, and the dynamic impacts of waves,tides, and currents.

In terms of human history, the earliest occupants orseasonal visitors to Delaware’s coast were members ofseveral Native American tribes: the Lenape, the Sikkonese,the Assateagues, and the Nanticokes. They lived along thecoast in dwellings and communities that would be

consideredtemporary bytoday’s standards.Delaware’s NativeAmerican tribesdid not buildpermanentstructures alongthe coast with theexpectation ofholding the lineagainst the sea. As the first

Europeanexplorers arrivedin the 1600s, the

earliest farms, homes, land grants and deeds wereestablished along the Delaware Bay and Atlantic Oceancoasts. However, society’s occupation of the coast withsome sense of permanence toward property developmentdid not occur until the late 1800s and early 1900s. [59]

Coastal Development: Pre World War II. CoastalDelaware was not always the highly developed area thatwe know today. Historical records show that the coast ofDelaware did not develop as rapidly as other parts of thestate due to its lack of accessibility, inhospitable nature(storms and insect pests) and the relatively low productivityof the lands for agricultural purposes (few tilling or grazingpossibilities). In fact, the first development of the coast,other than port communities such as Lewes, came in thelate 1800s and early 1900s, as religious camp meeting siteswere established in Rehoboth, Dewey, and Bethany Beach.

To encourage economic development in the early1900s, the State Public Lands Commission actually triedto put surplus state owned coastal property into hands ofprivate individuals for development. However, at that time,no one really had an interest in owning beach lands and

paying associated taxes because there was no obviousreturn or profit. The land that didn’t fall into private handsat that time is now part of the Delaware State Parks system,and provides important natural habitat and environmentsalong with well-used public access to beaches.

As is often the case today, railway and roadwayimprovements and transportation systems seemed tocontrol and impact the location and rate of developmentin coastal Delaware. Improved access and roadwayconstruction enhanced real estate opportunities through the1920s and 1930s. Substantial growth occurred in areas thatwere easily accessible, such as Bethany and Rehoboth,which were located on headlands where no bays orwaterways had to be crossed for access. In 1932, the statebuilt a road from Dewey Beach to Indian River Inlet, andboth residents and vacationers were able to enjoy longerstretches of Delaware’s ocean beaches. With greaterdemand by residents and tourists for homes, hotels,cottages, food, and entertainment, development eventuallyspread out along the coast from there.

Early Years of Beach Management. One factor thatdiscouraged early development of the coast was thedevastating effects of coastal storms. Once permanentstructures were constructed in Rehoboth and Bethany, theLegislature was called upon for assistance when coastalstorms destroyed or damaged beachfront property. [60]The first request that we are aware of came in 1915when the Commissioners of Rehoboth Beach requestedauthorization from the Legislature to borrow funds torecover from storm damage. Following more storm damageseveral years later, the town returned to the Legislature with

Human Use and Development

Along the Delaware Coast



59 Busy beach scene in 1906,Rehoboth Beach.

60 Beach erosion threatened to undermine homes inRehoboth Beach, 1920.

a request for direct state funding to recover from coastalstorm damage. The state eventually responded by buildingstructures in the early 1920s to alleviate what wasconsidered to be only storm damage at that time. [61]

In 1934, the State Highway Department was givenresponsibility for carrying out beach lands managementrecommendations. Coastal erosion was a problem that wasdealt with, but developedareas of the shoreline werefew, so they managed a0.5-mile section at a timewith no consideration ofpossible impactsdowndrift. At that time,the state of the artsolution for erosionmanagement includedgroin construction,intermittent beachnourishment projects,planting dune grass, anderecting dune fencing.From the 1930s throughthe1950s, beachfrontmanagement wascharacterized as treatmentof specific erosion problems at specific locations alongDelaware Bay and the Atlantic Ocean coast.

Coastal Development After World War II. A new waveof coastal development and population growth began in the1950s with a general post-war economic boom for thenation that resulted in much greater demand for familyvacations at the beach. More free time in the businessworld enabled people to take vacations, have weekendsfree, and general social change resulted in much moreactive use of beaches. Additionally, coastal Delawarebecame much more accessible to vacationers fromWashington and Baltimore after completion of theChesapeake Bay Bridge in the mid-1950s. Expansion of realestate development continued through the 1960s and 1970sas more and more people purchased coastal property forinvestments, businesses, or vacation residences.

The increase in coastal population and infrastructureresulted in the need to regulate construction along theshoreline. Additionally, severe impacts of coastal storms onproperty and communities provided additional impetus forthe state to develop an improved management program forits beaches. The devastating impacts of the 1962 stormresulted in an increased awareness that the State ofDelaware must regulate construction and provide fundingfor managing beach improvements.

The 1972 Beach Preservation Act was a landmark pieceof legislation that established a comprehensive beach anddune management program within DNREC. The programwas designed to: (1) include regulation of construction thatcould adversely affect the beach and protective primary

dune, and (2) promote programs and projects that improvethe overall recreational and protective aspects of beachand dune systems. In the 1970s, emphasis was placed onregulation of construction because there was so much openprivate land in coastal Delaware that had not yet beendeveloped. Through implementation of the buildingrestriction line, the regulatory program was successful

during the 1970s inconfining construction innew subdivisions to thearea landward of theprimary dune. The earlydevelopments in the areasnorth of Bethany Beachare good examples of thepositive impacts of the setback line. Beach erosion controland management throughthe 1970s included dunemanagement andimplementation of projectsto maintain beaches andrestore them after stormevents. Projects includedsmall beach nourishment

projects and groin construction. Along the Delaware Bayshoreline, groins were built in Slaughter Beach andBroadkill Beach in the 1950s and 1960s. Expansion ofgroin fields in Bethany continued through the 1960s, andin Rehoboth Beach [62] through the 1970s (Deauville,Henlopen Acres, North Shores). The last new groinconstructed in Delaware was completed at the Gordons

Pond area at CapeHenlopen StatePark in 1980.At the time, groinconstruction andperiodicnourishment werethe recommendedpractices for“controlling”erosion alongdeveloped stretchesof the coast.

Along with thedirect managementof beach landsbeing conductedby DNREC in thelate 1970s, therewere various otherentities involvedwith aspectsof beachmanagement.



62 Groin field in Rehoboth Beach.

61 Old timber structures built to control erosion, Rehoboth Beach, 1920.

The Geology Department and the Department of CivilEngineering at the University of Delaware were involved inresearch work associated with beach processes, particularlythe trends and mechanics ofbeach erosion and accretion,beach response to waves andcurrents, and the effects of stormsand sea-level rise. A tremendousamount of knowledge hascontributed to our understandingof beach erosion and theevolution and trends of ourbeaches. What emerged from theresearch was that beach erosionis complex, that it involves notonly storm erosion, but is alsodriven by sediment availability,sea-level rise, and humaninfluences. These research resultswere applied to coastalmanagement strategies andactivities with improvedknowledge and understanding ofthe dynamic coastal environment.

From the 1980s to Today.The decade of the 1980s broughtan unprecedented developmentboom to Delaware’s coast. Peoplemoved to the coast in droves,property values soared, and realestate developments proliferatedalong the entire length ofDelaware’s Atlantic coast. [63]The real estate boom of single-family homes meant growth inother areas, as retail andcommercial establishmentswere needed to service the newresidential growth. [64]


The compounding effects of continuing shorelineerosion, increased construction and the soaring value ofcoastal real estate and beach tourism has brought increased

demands and pressures on ourcoastal management program.Delaware beaches must bemanaged as natural resources formultiple uses that have equalimportance: biological habitat,storm protection, recreation andeconomic benefits. Beachmanagement strategies havebeen enhanced through the1980s and 1990s throughvaluable inputs from the coastalengineering research community.Improvements have been madein our ability to understand andpredict nearshore movement ofsand and the forces at work onthe beach face, resulting in moreeffective and efficient beachrestoration programs andprojects. One outcome of formerGovernor Castle’s EnvironmentalLegacy Program in 1986 wasthe development of a beachmanagement goal for the Stateof Delaware: “to assure thecontinued existence of beachesin Delaware that will providefor anticipated recreationalneeds and a cost-effective levelof storm protection for coastalproperties, structures, andinfrastructure for the next25+ years.” ■


64 The demand for coastal property impacted previously undeveloped areas in North Bethany between 1968 and 2003.

63 Construction has dramatically increased in coastalareas over the past 50 years, as shown at the top inFenwick Island (1954 and 1997), and below inNorth Bethany (1968 and 1997).

BGeneral knowledge about the causes of beach erosion hasimproved greatly over the past few decades. As describedin previous sections, scientists and coastal managersunderstand that sea-level rise results in a long-term trendof landward movement of the shoreline. Research andobservations have also demonstrated that waves andlongshore currents, especially those that accompany coastalstorms, are significant factors in the movement of sand andthe changing face of Delaware’s shoreline.

The dynamic nature of coastal environments results inan ever-changing shoreline—cycles of erosion and sandaccumulation over both long and short time frames inany one location. Although these cycles of erosion and

accumulationare oftenreported interms ofaverage long-term trends,fluctuatingperiods ofstability andchange may

occur over a period of days,weeks, months, or years. Forexample, in the Fenwick Islandarea, a section of coast thathad been rather stable formany years was impacted byrapid and unexpected change.DNREC survey records showthat over the 2-year span from 1977-1979, the Delawareshoreline moved landward at an average rate of morethan 30 feet each year, resulting in a permanentdisplacement of over 60 feet at the end of the 2-yearcycle.

Similar changes were observed in Dewey Beach [65]and in Rehoboth, where a beach that had been stable fordecades experienced a period of rapid change. Althoughthe exact cause of these quick changes in erosion rates

has not been determined, many of these beaches did returnto more average annual rates of erosion following theseshort cycles of rapid change.

The combined effects of wave forces, longshoretransport, storms, and sea-level rise generally result inlandward retreat of the shoreline. These changes may besudden and dramatic, such as a hundred feet of beacherosion within hours during a northeaster or hurricane.Or, the changes may be slow and nearly imperceptible,due to sea-level rise. The net result usually is evident over aperiod of decades, when fixed-position structures originallylocated a safe distance from the shoreline becomethreatened by waves and tides. Increased developmentalong the coast in recent years has put homes, hotels,businesses, and roadways in danger as the shorelinecontinues to move landward.

Coastal managers must evaluate past histories, presentday characteristics, and future predictions for our beaches.Long-term shoreline change rates have been documentedfor the Delaware Bay and Atlantic Ocean shoreline. Theyallow improved prediction of future shoreline behavior andposition. However, short-term changes in shoreline positionmay be dramatically impacted by the magnitude andfrequency of coastal storms. Management of beach erosionin Delaware is focused not only on long-term historicalshoreline change, but also on the most recent 10-15 yeartime frame, with an eye on possible future coastal changesresulting from impacts of longer term forces such as sea-level rise. While evaluation of short-term and long-termphysical coastal processes impacting our coast is a criticalcomponent for beach management policies, social andeconomic factors must also be incorporated into Delaware’scoastal management strategies.

Four ManagementOptionsThe dynamic nature of the Delawarecoastline, the importance of the beachas a natural habitat, the tremendousvalue of properties along the coast,and the economic value of the coastaltourism industry combine to create asignificant management challenge.

Any courseof actionchosen todeal withthe issue ofmanmadestructureson amigratingshorelinewill likelycarry a veryhigh costand require

Beach and Sand

Management

Strategies



65 Sequence of beachchanges at Dewey Beach(1970s-1990s).

and erosion has been perceived. Prior to implementation ofregulatory control, these projects were often implementedwithout consideration of the effects the structure may haveon adjacent properties or the beach itself.

Over the past century, a number of structural protectivemeasures designed to reduce potential damage have been

implemented alongthe Delaware coast.However, since thelate 1970s, the Stateof Delaware has notincluded shorelinehardening as part ofits primary coastalmanagement strategy.This section presentsa description ofcommon structuralmethods of shorelineprotection, theanticipated benefits ofeach, and some of theadverse effects thatmay result. A generaloverview of the

various types of hard structures is presented in thefollowing paragraphs.

Groins. A groin is constructed across the beach,perpendicular to the shoreline, and is designed to trap sandmoving in the longshore transport system. Commonly, theterm jetty (actually a structure used to stabilize an inlet) ismisused to refer to a groin. As sand accumulates on the

updrift side of thegroin, the beach atthat locationbecomes wider.[67] However,this is oftenaccompanied byaccelerated erosionof the downdriftbeach, whichreceives little or nosand via longshoretransport. Groinsdo not add anynew sand to thebeach; they merelyretain some of theexisting sand onthe updrift side ofthe groin.

changes in attitudes and land use practices at theindividual, local, regional, and statewide levels. Management options available for beach erosion controland property protection fall under four basic categories:no action, shoreline hardening, strategic retreat, andbeach nourishment.

No ActionThis alternative wouldinvolve the abandonmentof state policies andresponsibilities in all mattersrelated to beach erosioncontrol and coastal stormprotection. [66] Withoutstate involvement, federalparticipation in coastalprotection studies andprojects would likelydisappear without supportof a capable “local sponsor.”With responsibility fallingto local governments andprivate homeowner groups,remedial actions would likelyfall under the “hardening” category (see below) as theseactions provide initially affordable, site specific protectionof coastal areas and can be accomplished with little or noarea-wide organization, cooperation, or comprehensiveand long-range planning.

Management Implications of No Action. Coastalerosion would continue to impact our shoreline, and therewould be no overall planning program in place to beimplemented as a regional sediment management strategy.A likely result would be a narrowing of the active beachface, contributing to greater likelihood of storm damage tostructures and a diminishing recreational beach. Thisscenario would eventually adversely affect the tourismindustry, and eventually the real estate trade, constructionindustry, and related service industries:■ Reduction in number of beach visitors■ Diminished quality of “recreational beach experience”■ Loss of tourism revenue■ Lower rental prices■ Less beach repair work and reduced beach

maintenance costs

Shoreline Hardening The term shoreline hardening refers to construction of alltypes of structures (groins, jetties, and breakwaters) built toretain sand or to interfere with waves or currents to reducetheir impacts, or to protect property by reflecting waves andholding back tidal waters (revetments, seawalls andbulkheads). Installation of hard structures for the purposeof protecting buildings and property is usually one of thefirst actions considered by individual property owners andhomeowners associations once the threat of storm damage



67 Groins are structures designed to trapsand moving along the shoreline.

66 Consequences of “No Action” management alternative.

Engineering design of groins has evolved significantly inrecent years. The concept of notched groins and adjustablegroins is a recent coastal engineering concept that has beenimplemented in some coastal areas. The State of Delawarehas maintained groins in Bethany Beach and RehobothBeach over the past 70+ years. The U.S. Army Corps ofEngineers considered these groins in their evaluations ofthese two locations, and they recommended that the groinsremain in place.

Jetties. These structures are built at tidal inlets to stabilizethe locations of the inlets. Jetties constructed of a variety ofmaterials have been placed at several tidal inlets along theDelaware coast. Indian River Inlet, on the Atlantic coast, isstabilized by steel and stone jetties that were built in 1939[70]. Stone jetties are located at Roosevelt Inlet in Lewes,and timber and stone jetties stabilize the mouth of theMispillion River near Slaughter Beach.

Because jetties also interrupt longshore sand transport,the effect of jetties on adjacent beaches is similar to theeffect of groins: accretion occurs on the updrift side, anderosion occurs downdrift of the inlet. The offset is generallymore extreme at jettied inlets, due to the length and relativeimpermeability of the jetties and the inability of any sand tobe transported across the inlet opening. Material that doespass through or around the jetties contributes to shoalingeither in the interior of the inlet or offshore, depending uponthe direction of tidal currents.

The process of sand bypassing is a management toolthat has become an effective method of reducing theimpacts of interruption of longshore transport caused byjetties and associated navigation improvements at inlets andharbors. Sand bypassing can be conducted through the useof conventional dredges, or by using a permanent sandbypass pumping system that imitates natural processes bycontinuously pumping sand across the inlet to continue inthe longshore transport system.

Groins are usually constructed from steel, timber, orstone. The length, elevation, and spacing between groinsshould be designed on the basis of local wave energy and

beach slope.Groins too long orhigh tend toacceleratedowndrift erosionbecause they traptoo much sand.Groins too short,low, or permeableare ineffective,because they traptoo little sand.Flanking may occurif a groin does notextend far enoughlandward. Groinsare generallyconstructed ingroups called groinfields, such asthose at RehobothBeach and BethanyBeach. [68] Sincethe net direction oflongshore transport

is northward at these locations, sand generally accumulateson the south side of the groins, and erosion occurs on thenorth side. In the early 1920s, timber groins were often the onlypractical alternative available to coastal engineers andmanagers. Historic photographs of timber structuresdocument the evolution of coastal engineering practices inthe state, and provide an interesting history of coastalmanagement strategies. For example, this archivephotograph [69] shows timber groins that were built atCape Henlopen in the early 1920s.



69 In the 1920s, timber groins were installed at Cape Henlopento prevent beach erosion.

70 Indian River Inlet before bypass—inlet jetties interrupt the flowof sand along the beach.

68 Bethany Beach groin field.

To solve a beacherosion problemcaused by jettiesat Indian RiverInlet, a fixedsand-bypasssystem wasinstalled in thelate 1980s, andbypassing of sandbegan in January1990. [71] TheU.S. Army Corpsof Engineers andthe State of

Delaware have partnered on this project that serves as aninternational example of a successful inlet bypass system.A specially designed pump system and crane have beeninstalled on the south side of the inlet. Sand is pumpedfrom the sand accumulation area at the south jetty, througha pipe on the inlet bridge,and is deposited on thenorth side of the inlet. Thesand bypass volume andpumping rate has beendetermined through anengineering analysis ofhistoric erosion rates at thenorth inlet beach and thenatural rate of sedimenttransport in the vicinity.These analyses have led tothe adoption of the rate of100,000 cubic yards ofsand per year as thetarget volume of sand tobe bypassed at the site.The state has monitoredthe response of beachesboth north and south ofthe inlet since thebypass program wasimplemented. Continuedmonitoring and analysisof bypass data willenhance projectmanagement decisionsmade with the ultimate goal of protecting the Route 1 bridgeapproach, and stabilizing the north beach while minimizingimpacts on the south beach pumping site and adjacentshoreline areas.

Sand is not pumped year round, but an operationschedule has been developed based not only on beacherosion rates, but also on public safety and recreation in thearea. During summer months when there is highrecreational use of the beach area, pumping does not occur.

Bulkheads, Seawalls, and Revetments. Bulkheads,seawalls, and revetments are structures built parallel tothe shoreline, usually on the upper portion of the beach,to protect the land behind them from wave forces. Thesestructures are not used to protect or enhance the beachin any way. They may be constructed from a variety ofmaterials such as timber, steel, concrete, or stone.A bulkhead acts as a retaining wall to prevent land fromslumping and being washed away by waves. A seawall isgenerally a more massive structure designed to resist thefull impact of wave forces. The reflection of wave forcesby the vertical face of bulkheads and seawalls mayaggravate erosion of the beach in front of these structures.A revetment is a sloping layer (or layers) of stone orconcrete built to protect an embankment or shore structureagainst erosion.

Several design problems are commonly associated withthe failure of these types of structures. If the elevation of thestructure is too low, waves may overtop it causing erosionand scouring behind the structure, leading to collapse or

failure of the protection.If the structure does notextend deep enough,toe scour, erosion at thebase of the structurethat occurs as a resultof wave reflection orerosive currents, mayeventually cause thestructure to beundermined and slumpor collapse. If thestructure does notextend far enoughlandward, flanking, orerosion at the ends ofthe structure, occurswhen waves washaround it. Finally, astructure literally canbe torn apart by waves

crashing against it if improper buildingtechniques or undersized materials areused in its construction. [72] Evenproperly designed and built structureswill fail if wave energy exceeds thedesign strength of the structure or if

long-term erosional trends continue. This would result inextreme vulnerability from direct wave attack on the homeor building that had previously depended on the bulkheadfor protection.

Breakwaters. These structures are designed to reducewave energy reaching the shoreline. In most cases, thebreakwater is there to create a sheltered harbor for boatsand ships rather than to protect the shoreline from waveerosion. A breakwater may be located offshore, such as the



72 Failedbulkheads –Dewey Beach.

71 The Indian River Inlet bypass systempumps sand across the inlet, puttingsand back into the longshoretransport system.

inner and outer breakwaters in Breakwater Harbor, Lewes,or it may be connected to the shoreline and extend out intothe water, such as the Cape May-Lewes Ferry Terminalbreakwater in Lewes. Although the reduction of waveenergy due to the sheltering effect of the breakwater isbeneficial to the safe anchorage of vessels, a negative sideeffect is that the lowered energy conditions contribute toaccelerated shoaling and sedimentation in harbors. Shore-connected breakwaters may interrupt longshore transport,resulting in downdrift sand starvation similar to the effectsof the jetties at Indian River Inlet. Prior to the constructionof the outer and inner breakwaters in the 19th century,Breakwater Harbor was more than 30 feet deep. Today,most areas are less than 12 feet deep.

These types of offshore breakwater structures are notapplicable as effective protective measures alongDelaware’s openocean coast due tothe much largerwaves encounteredthere.

ManagementImplications ofShorelineHardening.Although installationof hard structureswas a commonshoreline protectionstrategy used fromthe 1920s to the1970s, they areseldom used now asa sole solution tobeach erosion. Manyof the structuresused to armor the shoreline were designed and installed as“defensive structures,” built as a last line of defense againstthe threat of breaking waves, rolling surf, and high tides.Between the 1940s and 1960s, groins were a popular wayto trap sand and build a modest beach area, without muchconsideration given to overall sand supply in adjacentareas. We now know that counting on a long-term, andendless supply of sand is unwise and unrealistic. Whilegroins may provide localized success, they may not beappropriate in areas with little or no sand supply unlesssand is added to the system in conjunction with a groinproject.

While structures such as bulkheads and seawalls maybe effective in protecting upland properties, they are noteffective in protecting the beach itself because they do notaddress the beach erosion problem seaward of theirlocation. In fact, in many communities that havebulkheaded or seawalled their waterfront, the beachcontinues to erode. Some states have imposed bans onconstruction of seawalls and bulkheads to avoid these

results. Groins and groin fields have been popular beachprotection strategies in the past, but they function bestwhen used in combination with sandy beach fill.Remember, it is the sand that provides a biological habitatand a recreational beach, and it is the beach that protectsadjacent properties, not the groins themselves.

The successes and failures of using hard structures tomanage a beach erosion problem have been reported inmany professional journals and conferences. For the mostpart, armoring the shore is not considered to be thepreferred method of preserving beaches in Delaware.

Strategic RetreatThe concept of strategic retreat is that of removingoceanfront buildings as the shoreline erodes to maintain abeach width or certain distance between buildings and the

water. An effectivestrategic retreatplan would involvesystematic removalof structures as thebeach migratesinland and thebuildings becomethreatened bywaves and surf.In this way, a widesandy beach areacan be maintainedas the beachposition migrateslandward.A study conductedin 2001 at theUniversity ofDelaware examinedthe economics of

strategic retreat in Delaware. The study explained that thereare social and economic costs associated with strategicretreat that include capital loss, transition loss, land loss,and proximity loss. Additionally, there are environmentalimpacts associated with retreat that include disturbance tobeach and dune habitats during structure removal anddemolition, introductions of toxins and pollution duringremoval, and disposal and/or recycling of the demolishedmaterials.

Management Implications of Strategic Retreat. Therealities of how to implement a strategic retreat policy mustbe considered before retreat can be considered an effectivemanagement tool. If strategic retreat is used to preservebeaches and dunes as recreational and protective features,then property acquisition will have to occur beforeproperties are damaged by coastal storms, waves, and tides.Thus, the “buyout” cost to government would likely begreatest when properties are sound, landward of the dune,and not in a damaged condition. In minimally populatedareas with low property values, strategic retreat may be a



practical managementapproach, as it may beaffordable to buyproperty and removeinfrastructure.However, theUniversity ofDelaware studymentioned aboveconcluded that the50-year social cost ofretreating fromDelaware’s Atlanticcoast would bebetween $156 millionand $319 million incurrent dollars. Theseestimates may varydepending uponassumed erosion ratesand land lossassumptions builtinto the study; for instance, if erosion rates, housing stock,or structural proximity vary, a different outcome may beexpected.

In another example, an analysis conducted for acommunity in North Carolina demonstrated that buying theoceanfront real estate at half its tax value would cost localand state taxpayers approximately half a billion dollars. Forthe same stretch of beach, the present value of the stateand local cost of beach nourishment over the next 20 yearsis $25.2 million. This analysis suggests that buyout is not astrong economic alternative in this situation. On the otherhand, government entities could act most frugally if landswere acquired in a damagedcondition to avoid paying topmarket price for the property.This would most likely occur aftera damaging coastal storm, at atime when human need andgovernment compassion are oftenat their highest.

Indeed, there are no easysolutions or clear implementationstrategies to accompany the issueof strategic retreat whileaccomplishing the managementgoal of preserving andmaintaining recreational andprotective beaches. Strategicretreat requires hard decision-making, funding, and firm commitment by theAdministration and the Legislature if it is to succeed.

BeachNourishmentThe process of addingsand to an erodingbeach to restore itswidth and elevation tospecified dimensions[73] is the only beachmanagement tool thatdirectly treats theproblem of sand loss onbeaches. Used almostexclusively indeveloped beach areas,nourishment iscommonlyaccomplished bypumping sand onto thebeach from an offshoresource by using adredge, although it may

also be conducted by trucking sand onto the beach. Beach nourishment does not prevent erosion or stop themovement of sand along a beach. It is actually a strategythat re-sets the erosional clock by adding sediment to thesystem and re-establishing the buffer of sand between theocean and structures. Beach nourishment achieves the goalof providing reasonable storm protection to developed areaswhile providing a recreational beach area as well asbiological habitat; all of the amenities that people wanttheir beaches to provide. [74] To be effective over the longterm, beach nourishment projects must be periodicallymaintained by re-nourishment projects.

The design and successof a beach nourishmentproject depends on manyfactors—including anevaluation of the causes oferosion and shorelinehistory of the area; adetermination of the levelof storm protection thatthe design beach is



74 Aerial photos of thenourishment process,Rehoboth Beach, 1998.

73 Beach nourishment is the process of placing sand on a beach torestore its width and elevation to specified dimensions.

expected to provide; calculation of desired beachdimensions, including height, width, dune area, andquantity of sand needed for the project; an assessment ofenvironmental impacts of the project; development ofbenefit/cost analysis, economic analysis, and funding planfor the initial project and maintenance; and establishmentof a long term monitoring program to allow a quantitativeassessment regarding the performance of the project.The success of the project is typically determined by thelongevity of the project and whether or not the projectprovided the expected benefits. In recent decades, beach nourishment has been viewedas a reasonable management option for many coastalcommunities. Beach nourishment is a management strategythat deals directly with the issue of sediment budget of abeach system. The direct and obvious benefit of

nourishmentis that thefundamentalnature ofthe problem(loss of sand)is directlytreated byadding sandfrom a sourceoutside ofthe erodingsystem.In this way,an entirebeach systembenefitsby theinvestmentof new sandinto thesedimentbudget.Typically, anadded benefitis realizedby beachesadjacent to

the nourish-ment project beaches, as sand is oftentransported into neighboring shoreline areas.

A 1995 National Research Council (NRC) study onbeach nourishment reports that while beach nourishmentis suitable for some, but not all locations where erosion isoccurring, it is a viable engineering alternative for shoreprotection and is the principal technique for beachrestoration. The NRC report suggests that “governmentauthorities with responsibilities for coastal protectionshould view beach nourishment as a valid alternativefor providing natural shore protection and recreationalopportunities, restoring dry beach area that has beenlost to erosion.”

Benefits. The primary benefits of beach nourishmentinclude storm damage reduction and enhancedrecreational/tourism opportunities. A wide beach not onlyacts as a direct buffer to absorb wave energy during stormevents, but it also provides a reservoir of sand that may betransported to an offshore bar. During storm events, largewaves will break on the offshore bar, reducing the amountof wave attack on the upper beach, thereby reducing theamount of erosion. Coastal engineers report that reductionsin wave height and wave forces due to relatively smalladditional beach widths are surprisingly large. In Floridaand North Carolina, several studies have documented thatdamage to structures after hurricanes was significantlyreduced in areas that had wider beaches.

A wide recreational beach increases tourismopportunities—people like to visit beaches, and the widerthe beach is, the more that people can enjoy it. Studieshave demonstrated that wide recreational beaches result inincreased income to resort areas, and healthy beaches are amajor draw for both domestic and foreign tourists. AlongDelaware’s Atlantic coast, millions of visitors annually flockto the beautiful state park beaches as well as beaches in thecoastal communities of Rehoboth, Dewey, Bethany, SouthBethany, and Fenwick Island. [75] If a wide sandy beachwere not accessible, or if water washed up to the sanddunes or under the boardwalk at each high tide, therecreational value of the beach would be significantlydiminished. [76] If the recreational beach experience is toocrowded, unpleasant, or simply not available, many visitorsto the Delaware shore might decide to travel to anothercoastal destination for a beach vacation the next year.

Although the most obvious benefits of a nourishmentproject include improved storm protection and creationof a wide recreational beach, additional benefits may be



76 Narrow beach—no room for recreation(Photo not taken in Delaware).

75 Wide recreational beach(post nourishment).

realized by restoring habitat in areas where it has beeneliminated or degraded through sand loss. [77]Maintenance of a wide upper beach and dune area resultsin benefits to plants and animals that have adapted to livingin the beach environment.Additional benefits may be derivedfrom nourishment by the variousanimals and birds that use thebeach as foraging and nestingsites.

Experience with other toolsand strategies utilized to safeguardstructures from the consequencesof beach erosion has led manybeach managers to most oftendecide to use the nourishmentstrategy to protect beaches. In fact,2-3 decades ago, a beach managermight have been more focused onways to protect buildings fromstorms and sea level rise. Incontrast, many beach managersare now more highly focused onpreserving and protecting thebeach itself for all of its importantcontributions as a naturalresource. Building hard walls orimpediments to sand flow (e.g., groins, jetties) has growninto disfavor, while beach nourishment has been a way toprotect and enhance the sandy coastline in a manner thatcreates a more natural beach system. [78] Managers mustweigh any impacts this kind of work may bring to thesystem against the coastal management benefits gained.

Potential Drawbacks.The use of beach nourishment as amanagement strategy is not without controversy andcriticism, usually focused on the temporary nature of thesolution provided by nourishment projects. Properlydesigned and implemented beach nourishment projectstypically provide storm and flood damage protection ondecadal time scales rather than centuries. Additionally,beach nourishment may not be justified or technically

feasible in some areas. Other drawbacks of beachnourishment include economic considerations andenvironmental issues.

The process of beach nourishment can disrupt existingbiological communities in borrow areas where dredgingoccurs, and in beach areas and shallow underwaterhabitats where nourishment sand is deposited. Potentialnegative environmental impacts can be both short-term andlong-term; some losses are temporary and accompanied byrecovery over time, while other losses may be consideredmore permanent disruptions.

There are several environmental issues related to theborrow sites that are used as the source of sand for beachnourishment projects. The most common source ofDelaware’s beach fill material are sand deposits in openocean areas that are found in water depths appropriate fordredging operations and are far enough offshore to avoidany possible detrimental effects to the beach. The primarybiological effect of dredging borrow sites is the removal ofthe animals that inhabit the sandy sediments, which may

also indirectly affect other species that use these bottomdwelling animals as a food source. Additionally, physicalimpacts may result from changes water quality, andincreases in turbidity due to sediment being suspended inthe water column.

There are some studies underway that will helpdocument the long-term physical alterations andenvironmental impacts resulting from the dredging of sandin offshore borrow sites, but the impacts on marine habitatshave not been well documented at this time. Until moreinformation is available, the most prudent action would beto design projects so that changes in the physical conditionand biological resources of a borrow site are minimized andare short term.



77 A wide beach provides habitat for a variety of plants andanimals.

78 Wide nourished beach provides benefits including storm protection and recreation.

Most of the animals living in sandy beach areas areburrowing organisms that are adapted to the stresses of thehigh-energy and constantly changing environment found ina surf zone and nearshore area. Many beachgoers arefamiliar with the animals found in the surf and swash zonesof an intertidal beach—ghost crabs, mole crabs, burrowingshrimp, worms, and small mollusks. When a beach isnourished, large volumes of sand are placed on the beachand in adjacent shallow nearshore areas where many ofthese animals live.

Placement of nourishment material on a beach maymimic the naturally occurring cycle of erosion anddeposition that occurs during and after high surf and stormevents along a coast. The volume of nourishment sedimentplaced on a beach usually occurs on a much greater scaleand more rapid time frame than would occur naturally.Some studies have shown that the larger, more mobileanimals such asghost crabs are ableto avoid impacts byleaving thenourishment area inresponse to thephysical disruptionor associated loss offood resources. Lessmobile animals suchas worms, mollusks,and mole crabs, arenot able to move outof the project site,and the extent ofnourishment impactswould be dependenton the depth ofsediment depositedand the animals’ability to burrow up through the sand.

The temporary loss of animal communities that live insandy intertidal areas is largely unavoidable during beachnourishment operations. The more important issue is howquickly these communities can recovery after the project iscompleted. There are a limited number of monitoringstudies available that have investigated recovery times,and many of these have documented temporary alterationsin the abundance, diversity, and species composition ofanimals living in a nourishment area. Monitoring studieshave not yet fully documented the time it takes for apopulation to recover at a nourished beach site, but somestudies have demonstrated that the time frame may rangefrom a few weeks to a few months.

Secondary or indirect impacts of nourishment projectsshould also be considered in future monitoring studies.Temporary losses or alterations to the sand dwellinganimals will likely impact other animals such as fish andbirds that may depend on them as a food source. Althoughnesting sea turtles are not an issue along the Delaware



coast, studies have shown that beach nourishment mayimpact the nesting success of sea turtle species, and specialpermit conditions are typically placed on projects involvinghopper dredges to minimize adverse impacts on sea turtles.For past Delaware nourishment projects, sea turtle spottershave been required to monitor the presence of sea turtlesand document potential turtle impacts at the offshoredredge site.

Concerns have also been raised regarding the effectsof beach nourishment on other threatened and endangeredbird and plant species. For example, the piping plover is anendangered bird species that nests on Delaware beachesabove the high tide line during spring and summer months.If improperly designed, nourishment projects could haveadverse impacts on plover habitat by creating unsuitablenesting habitat (incorrect sediment grain size) or byconducting the nourishment project during the nesting and

fledging season.This is an unlikelyimpact in Delawarebecause ploversprefer quiet beachareas without muchhuman contact, andnourishment inDelaware is doneonly in theurbanized portionsof the coast. Thereare permitrequirements thatmandate that aproject must avoidany contacts withplovers—even if theentire project mustbe halted. Yet,

studies have shown that beach nourishment can actuallyimprove the quality and availability of plover habitat bycreating a substrate that is higher, wider, and less vegetatedcompared to the eroded beach.

Borrow sites. Several environmental issues are related tothe borrow sites used as the source of sand for beachnourishment projects. The most common source ofDelaware’s beach fill material are sand deposits in openocean areas found in water depths appropriate for dredgingoperations and are far enough offshore to avoid anypossible detrimental effects to the beach. There are somestudies underway that will help document the long-termphysical alterations and environmental impacts resultingfrom the dredging of sand in offshore borrow sites, but theimpacts on marine habitats have not been well documentedat this time.

The primary biological effect of dredging borrow sitesis the removal of the animals that inhabit the sandysediments. This may also indirectly affect other species that



use these bottom dwelling animals as a food source.Additional impacts may result from increases in turbidity(due to sediment being suspended in the water column)if the site contains silts and clays. In areas with poorcirculation, other changes in water quality may result ifdeep holes are created in borrow areas, including lowdissolved oxygen levels or increased hydrogen sulfidelevels, which may have negative impacts on certainorganisms that cannot move out of the area. Secondaryeffects might also includeimpacts on organismsthat normally feed onanimals removed fromthe system, temporarilyor permanently, bydredging operations.

Additionalmonitoring studiesshould be conducted todetermine if these areasreturn to the physicaland biological conditionsthat existed beforedredging, and if so, howlong it takes. Until moreinformation is available,the most prudent actionwould be to design projects so that changes in the physicalcondition and biological resources of a borrow site areminimized and are short term.

Management Implications. Faced with an increasingdemand for the services that beaches offer to the public,at the same time beach widths were decreasing, DNRECdeveloped a management approach that incorporatesseveral different tools. [79] The regulation of constructionalong with a heavy reliance on sand replacement, as aresponse to erosion, combined with judicious use of hardstructures such as jetties and groins, is the course followedby Delaware to manage sand resources. Beach preservationefforts in Delaware took a significant turn in responseto the Beaches 2000 Report to the Governor in 1988.The committee behind the report saw the merits inbeach nourishment as long as the benefits resulting fromnourishment exceeded the cost of conducting the work.This remains the policy of the state and economic analysisof our beach nourishment work was conducted in 1998 andagain in 2004 to make certain that nourishment costs returna value higher than the cost.

Economic Considerations. Although scientific andtechnical issues are critically significant to beachmanagement strategies, economic considerations are alsoextremely important. Beach protection and beachnourishment projects are nearly always public decisions,often supported by large amounts of state and/or federalfunding. Before beach protection or nourishment projectsare initiated, evaluations are conducted to determine

general costs and benefits; although not always easilyachievable, the intent is to determine whether a givenproject provides benefits to society in general that areeither equal to or more valuable than the project costs.

The most obvious costs of a beach nourishmentproject are the costs of labor, equipment, and managementservices. Due to re-nourishment considerations, beachnourishment costs are also indirectly linked to the rate oferosion at the specific project site. The site-specific costs

must be weighed against the valueof property, local economy and taxbase, and many other intangiblefactors. The obvious benefitsfrom beach nourishment projectsare storm damage reduction,recreational benefits, andenvironmental/habitatenhancement benefits. If nourishment becomes thefavored solution for a stretch ofbeach, the next question is often

“Who willpay for it?”Many timesthe cost isspreadamong alargepopulationjust as anymajorpublicworksprojectwould be.

When the cost of a project outweighs the public benefit,there are several options: either alternative funding sourcesare pursued or the project is not done and some othersolution is sought. Beach communities faced with erosionmust weight the costs of beach nourishment against thevalue of property, cost of abandonment, or cost of structuralshore protection. In many cases, adding sand is the mostcost-effective solution for protecting private property andmaintaining the aesthetic and environmental quality of thebeach.

Hardening the shoreline produces minimal societalvalue; the beach itself may disappear, but the propertiesare protected and public infrastructure is protected fromstorm damage. However, no beach amenities are present.The no action alternative results in structure losses in thesurf zone and an unusable, unsafe beach. Nourishmentenhances all of the societal values (storm protection,recreation, and habitat). Strategic retreat does the samething as nourishment, but at a higher cost. Based onanalyses that have been conducted, the cost associatedwith buy-out of oceanfront property is extremely high andexceeds the cost of periodic nourishment. ■

79 Delaware’s coastline is arecreational, economicand natural resource.

SDelaware’s coastline is an extraordinarynatural resource of significant economic,environmental, recreational, and aestheticvalue. Barrier beach migration andbeach erosion along the coast are naturalprocesses. However, these naturalprocesses have been affected by humanactivities such as construction of structures,roadways, businesses and homes along theshoreline that have altered the naturalmovement and migration of sand bothalong the coast and across the barrier.There is a compelling need to continue to adopt andimplement coastal management policies to protect thestate’s substantial resources along the coast.

The benefits of our beaches are numerous and includerecreational and aesthetic values of a wide sandy beach,the considerable contribution of beaches to the economy,habitats provided for beach dependent life, and benefits ofbeaches for human access to the sea. The need for acomprehensive, coordinated, and proactive approach toshoreline management is emphasized by numerous factors:the coast is actively moving; storm activity alters the coast;and coastal population and development continues toincrease. Throughout the mid-20th century, state and federalagencies frequently implemented strategies for reducingcoastal erosion and protecting coastal development on acase-by-case basis. However, the natural processes and

humanactivities thatinfluencecoastal erosionand beach lossdo not followpoliticaljurisdictionalboundaries. By the late20th century,comprehensiveplanning andregulatoryprogramscontinued toevolve withcoastal science.Coastalgeologists andengineers have

demonstrated that any alteration of sediment transportwithin a region will likely impact, to some degree, themovement and availability of sand elsewhere within thatregion. This can result in either positive or negative impactson coastal resources and development, and these impactsmust be better understood. Today, broader regionalinteractions are being considered by coastal managers andscientists and are incorporated into the decision makingprocess. A regional approach to addressing coastal erosionand the reduction in sand supply, based on coastalwatershed and littoral cell (a portion of coastline wheresand flows in, along, and then out of an area) boundaries,is most effective in the long-term. Coordination of federal,state, and local agency activities is necessary to supportsuch regional approaches.

What does the future hold for our beaches? The Stateof Delaware will continue to work toward a program thatincludes: the concept of regional sediment management;dedicated funding to assure wide beaches in the long termfuture; coastal research that will help drive managementdecisions; continued public education; and minimizationof environmental impacts of beach nourishment. The stateis committed to conserving, restoring and enhancingDelaware’s coastline and beaches. Coastal managementcannot eliminate sea level rise, storm activity, or the naturalprocess of sediment movement and erosion along ourshoreline. However, a comprehensive management planfor our beaches has been developed with considerationof a wide range of environmental, economic, and socialfactors. These factors vary from the need to protect publichealth and safety, marine life and associated habitats,and recreational uses and facilities, to providing fullconsideration of the rights of public and private propertyowners along the coast. ■


Summary and

Conclusions

Summary and Conclusions

Beach Preservation Regulatory ProgramLands Act, the Wetlands Act, theCoastal Zone Act, and the BeachPreservation Act. Of these four laws,the Beach Preservation Act primarilycontrols the uses of Delaware’sbeaches and dunes, and requires apermit or letter of approval for anyonewishing to perform any land disturbingactivity within the area of the definedbeach.

1. Beach Preservation Act(1972 and 1983) Title 7,Delaware Code, Chapter 68

The Beach Preservation Act controlsland uses on beaches and dunes, withno construction generally allowed onbeaches or on primary dunes. TheBeach Preservation Act first becamelaw in 1972 and was revised in 1983.It declares the beaches of the AtlanticOcean and Delaware Bay shorelines ofDelaware to be natural features thatfurnish recreational opportunities andprovide storm protection for personsand property, as well as being animportant economic resource for thepeople of the state. The BeachPreservation Act acknowledges thatnatural forces have created and willcontinue to alter (via beach erosionand shoreline migration) the beachesof the state, and that development ofbeaches must be done withconsideration given to the naturalforces impacting on them.

The purposes of the act are to“…enhance, preserve, and protect thepublic and private beaches of thestate, to mitigate beach erosion, tocreate civil and criminal remedies foracts destructive of beaches, toprescribe the penalties for such acts,and to vest in the Department ofNatural Resources and EnvironmentalControl the authority to adopt suchrules and regulations it deemsnecessary to effectuate the purposes ofthis chapter.”

The Beach Preservation Act isadministered by the DNREC, Divisionof Soil and Water Conservation,Shoreline and Waterway ManagementSection, through the RegulationsGoverning Beach Protection and theUse of Beaches. The originalregulations were promulgated in 1974,

Appendixes


Regulations and ordinances governingbeaches and coastal development inDelaware are administered by federal,state, and local authorities. Theseregulations and ordinances aredesigned to protect the natural coastalenvironment and to reduce stormdamage to coastal properties. Certainprograms require permits for activitiesconducted in the beach area, andappropriate authorities should beconsulted before alterations are madeto the beach environment or beforeconstruction activities commence.

Federal RegulationThe regulation of activities on beachesand in adjacent coastal waters andwetlands is controlled by severalfederal agencies. The principalregulatory activities are administeredby the U.S. Army Corps of Engineers(USACE), the Federal EmergencyManagement Agency (FEMA), and theOffice of Ocean and Coastal ResourceManagement (OCRM. In addition, allfederal agencies must comply withFederal Executive Order 11988, FloodPlain Management, and ExecutiveOrder 11980, Protection of Wetlands.These regulations establish the federalpolicy to avoid direct or indirectsupport of development in floodplainor wetlands areas, and to avoidadverse environmental impactsassociated with activities in theprotected coastal zone area.

State RegulationThe Delaware coast is managed andprotected by the Delaware Departmentof Natural Resources andEnvironmental Control (DNREC).Delaware’s Coastal ManagementProgram is the umbrella policyprogram that serves to determineappropriate land and water uses in thecoastal area while protecting the state’snatural resources. The state hasestablished a number of policies,standards, and regulations thatcondition, restrict, or prohibit someuses in parts of the coastal zone. Fourstate laws form most of the basis formanagement of Delaware’s coastalareas. These include the Underwater

with the most recently revisedregulations adopted in 1983. Theprimary purpose of the regulations isto enhance, preserve, and protectpublic and private beaches of the statethrough a permit process. Theregulations establish the concept of abuilding line which serves as a point ofreference for construction activities.The function of the building line is todelineate a seaward boundary forconstruction activities, and to establisha protected dune zone. Along theAtlantic Coast, the building line is 100feet landward of the seawardmost 10-foot elevation contour. Along beacheson Delaware Bay from Cape Henlopento Primehook, the building line islocated 100 feet landward of the 7-footcontour elevation, and fromPrimehook to Pickering Beach, the lineis 75 feet landward of the 7-footelevation contour.

The primary goal of the beachregulations is to require that allconstruction activities be conductedlandward of the building line.Exceptions are made where there isinadequate room or space available ona lot to construct entirely landward ofthe building line or where theproposed project requires a shorefrontlocation for its intended purpose (e.g.,a beach access walkway structure).Copies of the regulations and the mapsdepicting the location of the buildingline are available from the Shorelineand Waterway Management Sectionoffice in Dover.

2. Delaware’s CoastalManagement Program

Delaware’s Coastal ManagementProgram was implemented in August1979 to guide development alongDelaware’s coastline. The CoastalManagement Program is designed toenforce and encourage soundmanagement policies and to permitorderly growth in the coastal zonewhile protecting natural resources.A system of standards, guidelines,and controls to manage coastal landand water uses was developed underthe Coastal Management Program topermit coordinated, rationalevaluations concerning Delaware’scoastal areas.

Delaware’s Coastal ManagementProgram offers four principal benefitsto the State’s residents. These include:(1) more effective protection and useof the land and water resources ofDelaware’s coast; (2) control overfederal activities affecting the state’scoastal areas (federal consistency);(3) financial assistance from the federalgovernment for administering theprogram; and (4) increased publicawareness of the coast, its resources,and the issues of its use.

3. The Coastal Zone Act(1971) Title 7, Delaware Code,Chapter 70

In 1971, Delaware’s Coastal Zone Actwas enacted to control industrialdevelopment in the coastal zone.The purpose of the act is to controlindustrial development alongDelaware’s coastline in order to“…better protect the naturalenvironment of its bay and coastalareas and to safeguard their useprimarily for recreation and tourism.”The Coastal Zone Act prohibits heavyindustry and bulk product transferfacilities from locating in the coastalareas of Delaware, and subjectsmanufacturing uses to a permit systemto ensure protection of coastalresources. DNREC is responsible foradministration of the Coastal Zone Act.

4. The Subaqueous Lands Act,Title 7, Delaware Code,Chapter 72

The Subaqueous Lands Act regulatesuses in State subaqueous (submergedlands and tidelands) lands whichinclude non-tidal streams, lakes,ponds and tidal waters channelwardof the mean high tide line. TheSubaqueous Lands Act is administeredby DNREC, Division of WaterResources, Wetlands and SubaqueousLands Section. The administrativerules used to enforce the act areoutlined in the Regulations Governingthe Use of Subaqueous Lands(adopted May 8, 1991 and amendedSeptember 2, 1992).

5. The Wetlands Act, Title 7,Delaware Code, Chapter 66

The Wetlands Act regulates activitiesin tidal wetlands, both saltwater andfreshwater, to ensure preservation andprotection of these resources. TheWetlands Act is administered byDNREC, Division of Water Resources,Wetlands and Subaqueous LandsSection. The administrative rules usedto enforce the act are outlined in theWetlands Regulations (adoptedDecember 23, 1976; revised June 29,1984, and November 4, 1994).Wetlands under DNREC jurisdictionare depicted on State Regulated TidalWetlands Maps.


Appendixes

Local RegulationState regulations and restrictions aregenerally applicable to all beachesalong the Delaware ocean and baycoastlines. However, local concern forcoastal problems has resulted in thedevelopment and adoption ofordinances pertaining to flood hazards,coastal construction, and beachmanagement by municipal authorities.Similarly, county officials haveadopted ordinances and specialregulations for coastal protection.The unincorporated developmentsand communities without their ownzoning authority fall under thejurisdiction of the county planningand zoning authorities.

Along with their general zoningordinances, local municipalities andKent and Sussex Counties haveadopted flood hazard zoningordinances as required by FEMA.These ordinances outline criteria forflood-safe construction and placementof homes. Kent County has establishedordinances which define minimumfloodproof standards and constructionstandards for structures in coastalhigh-hazard areas (Section 9, KentCounty zoning ordinances). SussexCounty also has special ordinancesfor coastal protection. These zoningordinances outline restrictions thatserve to protect the dune and beach,and provide construction and landdevelopment controls within thedesignated flood-prone areas. Theconstruction controls outlined in theordinances include building criteriafor: first floor elevations, anchoringand placement of structures, basementfloors and foundation wells, interiorfloors, walls and ceilings, storageareas, electrical systems, andplumbing (Sections 12, 13, and 14,Sussex County Zoning Ordinances).

Coastal Property Checklist


Appendixes

If you live in a coastal area, you arevulnerable to the effects of coastalstorms. High winds and waves damageand destroy improperly constructedhomes. Floating debris can crackfoundation piles causing collapse of thehome or break windows and doors.Pressures from floodwaters on solidfoundations can lead to collapse.

You can prevent or minimize damage!By taking precautions during initialconstruction or by making modificationsto an existing home, you can minimizedamage and loss.

FloodingDo you know the projected floodelevation for your area? Ask yourbuilding department to see a flood mapof your community.❏ Is the first floor of the dwelling

located above the projected floodelevation for your area?

❏ If your house is elevated on piles, doyou have an open foundation, free ofobstruction, that allows fast-movingwaves and water to flow beneath thebuilding?

❏ If storage areas or other enclosuresare needed below projected floodelevations, they must be constructedwith breakaway walls to allow waterto flow-through unobstructed. Isyour enclosure breakaway?

❏ Are steps used for accessing thebeach from the structure or thepedestrian dune crossover elevatedor removed out of the reach of wavesand floodwaters?

❏ Are the main electric panel, outletsand switches located at least 12inches above potential floodwaters?

❏ Are the washer and dryer, furnaceand water heater elevated abovepotential floodwaters?

❏ Are outside air conditioningcompressors and heat pumpselevated?

❏ Is the fuel tank securely anchored?It can tip over or float in a floodcausing fuel to spill or catch afire.Cleaning a house inundated withwater containing fuel oil can bedifficult and expensive.

❏ What is the orientation of cross-bracing on the pilings? Diagonal

bracing will obstruct velocityfloodwaters and waves and willoften trap debris, therefore bracingmust be placed parallel to theprimary direction of flow.

❏ Does the sewer have a back flowvalve? Contact a licensed plumber toinstall the valve.

❏ Are there potential projectiles suchas landscaping ties, cinder blocks,cement patio blocks, pile butts, orsplit rail fences located in thepathway of waves and flood waters?These objects can crack and damagepiles and lower level enclosurescausing possible collapse of thestructure.

Wind❏ Are windows and exposed glass

surfaces protected by stormshutters? This is one of the bestways to protect your home againstwind and flying debris. 5/8 inchthick exterior grade plywood worksjust as well.

❏ Is the roof fastened to the walls withgalvanized metal hurricane straps?This will reduce the risk of losingyour roof to high winds.

❏ Are the galvanized straps, hangersand joist to beam ties corrosion free?Corroded metal components can failduring extreme wind events. Theseshould be replaced when corroded.

❏ Are the foundation piles notchedless than 50% of the pile crosssection? Overnotching can leadto failure of the piles.

❏ Are deck and lawn furniture whichare likely to become airborne debrissecurely fastened or taken in doors?

Erosion❏ Are your foundation piles deep

enough to survive a coastal storm?❏ Is the dune in front of your home

well vegetated to prevent winderosion?

❏ Is the dune of sufficient height andwidth to prevent overtopping bywaves during a storm?

❏ Are there bare, low areas in the dunecreated by walking over the dune toaccess the beach? These areas areweak spots that will allow waves to

flow over the dune and cause loss ofthe dune and subsequently allowwaves and water into the house.

❏ Is your home built on a concreteslab and located on the ocean orbay front? Concrete slabs can beundermined and destroyed duringstorms causing the collapse of thestructure. If possible, elevate thestructure on pilings.

Structural❏ Inspect strapping for corrosion and

replace if necessary.❏ Check roof for loose or missing

shingles. Be certain gutters are clearof debris.

❏ Inspect condition of storm shuttersor plywood used to protect windowsand doors. Cover all large windows,doors (especially patio doors) withsecurely fastened, impact resistantshutters with proper mountingfixtures.

❏ Make sure all doors and windowsare caulked and/or weather stripped.

❏ Inspect sewer backflow valves.❏ Inspect condition of elevated

utilities and supporting platforms.Be sure utilities are securelyanchored to the supporting frame.

Lot and Land Area❏ Remove, secure or store any objects

that may be carried by waves orwinds (i.e., deck furniture,landscaping, construction materials,etc.).

❏ Raise or remove steps accessing thebeach.

❏ Check condition of dune (width andelevation). Inspect condition ofbeachgrass. Replant bare areasin the spring and fertilize as needed.

❏ Trim back dead or weak branchesfrom trees.

This checklist is not all-inclusive and isnot intended to replace local buildingcode requirements or to serve as the onlyoptions for protecting your home fromstorm damage. For more information,contact your local building official or abuilding professional such as a coastalengineer, architect or experiencedcontractor.

Breaker zone – Area within which wavesapproaching the coast begin to break,typically landward of 16-33 feet(5-10 meters) water depths.

Breakwater – Linear or mound-like coastal-engineering structure constructed offshoreparallel to the shoreline to protect ashoreline, harbor, or anchorage from stormwaves.

Bulkhead – Structure or partition to retainor prevent sliding of the land. A secondarypurpose is to protect the upland againstdamage from wave action.

Bypassing, sand – Hydraulic or mechanicalmovement of sand, from an area of accretionto a downdrift area of erosion, across abarrier to natural sand transport such as aninlet or harbor entrance. The hydraulicmovement may include natural movement aswell as movement caused by man.

Coast – Strip of land of indefinite width (maybe several kilometers) that extends from theshoreline inland to the first major change interrain features. The land regarded as nearthe shoreline.

Coastal processes – Natural forces andprocesses that affect the shore and thenearshore seabed.

Coastline – The boundary between coastalupland and the shore.

Crest – Highest point on a wave, beach face,berm, ridge, hill or shore structure.

Current – Flow of water. This flow may bepersistent (as in a stream) or temporary(as a wind driven current).

Current, coastal – One of the offshorecurrents flowing generally parallel to theshoreline in the deeper water seaward ofthe surf zone; may be caused by winds orre-distribution of water mass.

Current, littoral – Any current in the littoralzone caused primarily by wave action,e.g., longshore or rip current.

Current, longshore – Littoral current in thebreaker zone that moves, essentially parallelto the shore, usually generated by wavesbreaking at an angle to the shoreline.

Cusp – Scallop-like ridges and depressions inthe sand spaced at regular intervals along thebeach.

Downdrift – In the direction of thepredominant movement of sediment alongthe shore; the side of a groin, jetty, or otherstructure that is deprived of sand.

Dredging – Removal of sediment or theexcavation of tidal or subtidal bottom toprovide sufficient depths for navigation oranchorage, or to obtain material forconstruction or for beach nourishment.

Barrier spit – Barrier beach connected toland at one end, with the other endextending into a body of water such as a bay,lagoon, or ocean. Example: Cape Henlopen.

Bathymetry – Measurement of depths ofwater in oceans, seas, and bays; alsoinformation derived from suchmeasurements.

Bay – Recess in the shore or an inlet of a seabetween two capes or headlands, not as largeas a gulf but larger than a cove. Example:Delaware Bay.

Beach – Zone of unconsolidated materialthat extends landward from the low waterline to the place where there is markedchange in material or physiographic form,or to the line of permanent vegetation(usually the effective limit of storm waves).

Beach erosion – Carrying away of beachmaterials by wave action, tidal currents,littoral currents, or wind.

Beach face – Section of the beach normallyexposed to the action of wave uprush. Theforeshore of a beach.

Beach fill – Material placed on a beach tore-nourish eroding shores.

Beach material – Granular sediments (sand,stones) moved by the water and wind to theshore.

Beach nourishment – Process ofreplenishing a beach with material (usuallysand) obtained from another location.

Beach width – Horizontal dimension of thebeach measured perpendicular to theshoreline, from the still water level to thelandward limit of the beach.

Berm – In a barrier beach system, therelatively flat sandy area between the bermcrest and the dunes formed by the deposit ofmaterial by wave action. Some beaches haveno berm; others have one or several.

Berm crest – Seaward limit of a berm.

Breaker – Wave breaking on a shore, over areef, etc. Breakers may be classified into fourtypes:

Collapsing – Breaking over the lowerhalf of the wave.Plunging – Crest curls over an airpocket and breaking usually occurs witha crash of the crest into the precedingwave trough.Spilling – Bubbles and turbulent waterspill down front face of wave. The upper25 percent of the front face may becomevertical before breaking. Breakinggenerally occurs over quite a horizontaldistance.Surging – Wave peaks up and slides upthe beach face with little or no bubbleformation.

GAccretion – Natural or artificial build up ofland. Natural accretion is the buildup ofland, solely by the action of the forces ofnature, on a beach by deposition ofwaterborne material. Artificial accretion is asimilar buildup of land by human action,such as the accretion formed by a groin,breakwater, or beach fill deposition bymechanical means.

Alongshore (longshore) – Parallel to andnear the shoreline; same as longshore.

Armor stone (armor layer) – Number ofrelatively large quarrystone or concretepieces that form primary wave protectionon the outer surfaces of shore protectionstructures.

Armored shore – Shore with constructedshore protection.

A-Zone – Flood zone subject to still-waterflooding during storms that have a 100-yearrecurrence interval.

Backbarrier flats – Low-lying sandy regionson the landward side of the sand dunes;often covered with salt-tolerant grasses andshrubs.

Backbarrier marsh – Marsh formed on thelandward side of a coastal barrier, oftencontaining significant coarse sediment thathas washed in from the seaward side.

Backrush – Seaward return of waterfollowing the uprush of waves. For any giventide stage, the point of farthest returnseaward of the backrush is known as thelimit of backrush.

Backshore (backbeach) – That zone of shoreor beach lying between the foreshore and thedunes and acted upon by waves only duringsevere storms, especially when combinedwith exceptionally high water. It includes theberm or berms.

Bar – Submerged or emerged mound of sand,gravel, or shell material built on the oceanfloor in shallow water by waves and currents.

Barrier beach – Sedimentary land-formessentially parallel to the shore, the crestof which is above normal high water level.Also called a barrier island.

Barrier island – Barrier beach that isunconnected to the mainland.

Barrier lagoon – Bay roughly parallel to thecoast and separated from the open ocean bybarrier islands or spits. Examples: RehobothBay, Indian River Bay, Little Assawoman Bay.

Glossary


Appendixes

Northeaster – On the U.S. east coast, astorm (low-pressure system) whosecounterclockwise winds approach the shorefrom the northeast as the storm passes anarea. Waves approaching from the northeastdirection can cause coastal erosion.

Nourishment – Placement of sediment on abeach or dunes by mechanical means.

Overtopping – Passing of water over thetop of a beach berm, dike, or other shoreprotection structure as a result of waverun-up or surge action.

Overwash – Uprush and overtopping of acoastal dune by storm waters. Sediment isusually carried with the overwashing waterand deposited, usually in a fan shape, onthe landward side of the dune or barrier.

Permeability – Ability of water to flowthrough soil, crushed rock or other material.

Permeable groin – Groin with openingslarge enough to permit passage ofappreciable quantities of sediment.

Pile – Long, heavy section of timber,concrete or metal driven or jetted into theearth or seabed to serve as a support or toprovide protection. (also, piling)

Porosity – Percentage of the total volume ofa soil, or stones, occupied by air or water,but not by solid particles.

Reach – Section of coastline that hascharacteristics in common.

Recession – Landward movement of theshoreline, beach, or seaward edge of bank orbluff.

Revetment – Apron-like, sloped, coastal-engineering structure built on a dune face orfronting a seawall; designed to dissipate theforce of storm waves and preventundermining of a seawall, dune, or placedfill.

Rip current – Strong current flowingseaward from the shore. It is the returnmovement of water piled up on the shore byincoming waves and wind.

Riprap – Layer, facing, or protective moundof stones placed to prevent erosion, scour, orsloughing of a structure or embankment; alsothe stone so used.

Risk – Possibility of negative outcomes or aloss.

Salt marsh – A wetland periodicallyinundated by salt water, characterized byemergent herbaceous vegetation adapted tosaturated soil conditions; an importantinterface between terrestrial and marinehabitats.

Hurricane – Intense tropical cyclone withwinds that move counterclockwise around alow-pressure system; maximum sustainedwinds of 74 miles per hour or greater.

Impermeable groin – Groin through whichsand cannot pass.

Inshore (zone) – In beach terminology, thezone of variable width extending from thelow water line through the breaker zone.

Jetty – Narrow, elongated coastal-engineering structure built perpendicular tothe shoreline at inlets; designed to preventlongshore drift from filling the inlet and toprovide protection for navigation.

Lagoon – Shallow body of water, as a pondor sea, usually connected to the sea (cfbarrier lagoon).

Littoral – Pertaining to the shore of a sea.

Littoral drift – Sedimentary material such assand and stones moved near the shore in thelittoral zone under the influence of wavesand currents.

Littoral transport – Movement of littoraldrift in the littoral zone by waves andcurrents; includes movement parallel(longshore transport) and perpendicular(cross-shore or on/off-shore transport) to theshore.

Littoral zone – In beach terminology, anindefinite zone extending seaward from theshoreline to just beyond the breaker zone.

Longshore (alongshore) – Roughly parallel toand near the shoreline.

Low tide – Minimum elevation reached byeach falling tide.

Marsh – Area of soft, wet, or periodicallyinundated land, usually characterized bygrasses and other low growth such as shrubs.

Mean high water (MHW) – Average heightof all of the high waters recorded at a givenplace over a 19-year period.

Mean low water (MLW) – Average height ofall of the low waters recorded at a givenplace over a 19-year period.

Mean sea level (MSL) – Average height ofthe surface of the sea at a given place of allstages of the tide over a 19-year period.

Neap tide – Tide occurring near the time ofquadrature of the moon with the sun (firstand last quarters). The neap tide range isusually 10-30% less than the mean tidalrange.

Nearshore – Zone extending seaward fromthe shoreline well beyond the breaker zone;typically to about 66 feet (20 meters) waterdepth.

Dune – Any natural hill, mound, or ridgeof sediment landward of a coastal bermdeposited by the wind or by storm overwash;sediment deposited by artificial means andserving the purpose of storm-damageprevention and flood control.

Duration – In wave forecasting, the length oftime the wind blows in nearly the samedirection over a body of water.

Ebb tide –The period of tide between highwater and low water; a falling tide.

Erosion – Wearing away of land by theaction of natural forces. On a beach, thecarrying away of beach material by waveaction, tidal currents, littoral currents, orwind.

Estuary – Part of a river that is affected bytides. The region near a river mouth in whichthe freshwater of the river mixes with thesaltwater of the sea.

Estuarine – Pertaining to an estuary.

Exposure – Something of value that could bedamaged or destroyed by a loss. It can betangible (building, land, income) orintangible (access, enjoyment).

Fetch – Distance over water in which wavesare generated by a wind having a constantdirection and speed.

Flood tide – Period of time between lowwater and high water; a rising tide.

Foredune – Front dune immediately behindthe backshore.

Foreshore – The steeper part of the beachthat extends from the low water mark to theupper limit of high tide; the beach face.

Gabion – Wire mesh basket containing stoneor crushed rock, designed to protect a slopefrom erosion by waves or currents.Sometimes used as a backing or foundationfor shore protection structures.

Gravel – Small, loose stone; approximately0.08—3.0 inches (2-76 millimeters) indiameter.

Groin – Narrow, elongated coastal-engineering structure built on the beachperpendicular to the trend of the beach; itsintended purpose is to trap sediment to buildup a section of beach.

Hazard – Any condition that increases thelikely frequency or severity of a loss.

Headland – Area of high elevation moreresistant to erosion than surrounding areasand less susceptible to flooding. Headlandscan supply sand and gravel to beaches.

High tide – Maximum elevation reached byeach rising tide.


Appendixes

Sand – Rock grains, most commonly quartz;that are 0.0025–0.19 inches (0.0625–2.0 mm)in diameter.

Scarp – Almost vertical slope along thebeach caused by wave erosion. It may varyin height from a few inches to several feet,depending on wave action and the natureand composition of the beach.

Scour – Removal of underwater material bywaves and currents, especially at the base ortoe of a shore structure.

Seawall – Vertical wall-like coastal-engineering structure built parallel to thebeach or duneline and usually located atthe back of the beach or the seaward edgeof the dune.

Sediment – Solid particles or masses ofparticles that originate from the weathering ofrocks and are transported, suspended in, ordeposited by air, water, or ice, or by othernatural agents such as chemical precipitationand organic secretion.

Setback (setback distance) - Selected(or required) space between a building(or other structure) and a boundary.

Shallow water – Water of such a depth thatsurface waves are noticeably affected by theseabed. In terms of wave shoaling, it is waterof depths less than one-half the wavelength.

Sheetpile – Planks or sheets of constructionmaterial designed to be driven into theground or seabed so that the edges of eachpile interlock with the edges of adjoiningpiles.

Shoal (noun) – Shallow area in the seabed,comprised of any material except rock, whichmay endanger surface navigation.

Shoal (verb) – (1) To become shallowgradually. (2) To cause to become shallow.(3) To proceed from a greater to a lesserdepth of water.

Shore – Narrow strip of land in immediatecontact with the sea, including the zonebetween high and low water lines. A shore ofunconsolidated material is usually called abeach.

Shoreline – Intersection of a sea with theshore or beach.

Silt – Loose rock particles; smaller than sandparticles and larger than clay particles.

Slope – Degree of surface inclination abovea horizontal reference surface. Usuallyexpressed as a ratio, such as 1:25 or 1 on 25indicating 1 unit vertical rise in 25 units ofhorizontal distance; or in a decimal fraction(0.04); degrees (2* 18'); or percent(4 percent).

Soil – Layer of weathered, unattachedparticles containing organic matter andcapable of supporting plant growth.

Spit – Point of land or projecting into abody of water from the shore. Example:Cape Henlopen.

Spring tide – Tide that occurs at or near thetime of new or full moon (syzygy), and thatrises highest and falls lowest from the meansea level.

Squall line – Line of strong wind areasadvancing ahead of a weather system along aboundary between air masses at muchdifferent temperatures.

Storm surge (wind setup, storm rise) – Riseabove normal water level on the open coastdue to wind stress on the water surface overa long distance (fetch).

Surf zone – Area between the outermostbreaker and the limit of wave uprush.

Swale – Low area between two beach ridges.

Swash zone – Area of wave action on abeach face from the lower limit of wavebackrush to the upper limit of wave uprush.

Tide – Periodic rise and fall of water thatresults from gravitational attraction of themoon, the sun, and other astronomicalbodies acting upon the rotating earth.

Toe – Lowest part of a structure forming thetransition to the seabed, or the lowest part ofa slope forming a transition to a beach orterrace.

Trough – (1) Lowest part of a wave; (2)Depression in the seabed between bars—often created by breaking waves.

Updrift – Direction opposite that of thepredominant movement of sediment alongthe shore; the side of a groin, jetty, or otherstructure where sand accumulates.

Upland – General term for land or groundthat is higher than the floodplain.

Uprush – Landward flow of water up ontothe beach that occurs when a wave breaks;Same as runup.

Velocity zone (V-zone) – Zone subject tovelocity-water flooding during storms thathave a 100-year recurrence interval. Incoastal areas the V-zone generally extendsinland to the point where the 100-year flooddepth is insufficient to support a 3-foot-highbreaking wave.

Washover – See Overwash.

Water wave – Moving ridge, deformation, orundulation of the water surface; the transferof energy across the water surface.

Wave breaking – Breakdown of a waveprofile with a reduction in wave energy andwave height due to an unstable wave shape.

Wave climate – Seasonal and annualdistribution of wave heights, periods, anddirections at a particular location.

Wave crest – Highest part of a wave.

Wave direction – Direction from which awave approaches.

Wave height – Vertical distance between acrest and adjoining trough.

Wave length – Horizontal distance betweentwo adjacent, successive wave crests.

Wave period – Time for a wave crest totravel a distance of one wave length.

Wave reflection – Process by which wavepower and wave energy is returned seaward.

Wave refraction – The bending of waves asthey travel through varying water depths.Wave direction generally turns towardregions of shallow water and away fromregions of deep water.

Wave run-up (swash) – Rush of water up astructure or beach following the breaking of awave; measured as the vertical height abovestill-water level to which the rush of waterreaches.

Wave trough – Lowest water surfacebetween two adjoining wave crests.

Wetland – Land where saturation with wateris the dominant factor in determining thenature of soil development and the types ofplant communities that live in the soil and onthe land.


Appendixes

Appendixes

Resources for

Additional Information

Against the Tide: The Battle for America’s Beachesby Cornelia Dean (Columbia University Press, 1999).

Barrier Island Handbookby Stephen P. Leatherman(Coastal Publications Series, College Park, MD, 1988).

Beach Nourishment and Protectionby the National Research Council(National Academy Press, 1995).

Beach Nourishment: Theory and Practiceby Robert G. Dean(World Scientific, 2002).

Beach Processes and Sedimentationby Paul D. Komar (Prentice-Hall, Inc., 1998).

Beaches and Coastsby Richard A. Davis, Jr. and Duncan M. Fitzgerald(Blackwell Publishing, 2004).

The Beaches are Moving: The Drowning ofAmerica’s Shoreline: with a new epilogueby Wallace Kaufman and Orrin H. Pilkey(Duke University Press, 1983).

Coastal Processes with Engineering Applicationsby Robert G. Dean and Robert A. Dalrymple(Cambridge University Press, 2002).

Coastal Sedimentary Environmentsby Richard A. Davis, Jr. (ed.)(Springer-Verlag, 1985).

The Evolving Coastby Richard A. Davis, Jr.(Scientific American Library, 1994).

Handbook of Beach andNearshore Morphodynamicsby A. D. Short (ed.)(John Wiley & Sons, 1999).

Waves and Beachesby Willard Bascom(Anchor Doubleday Press, 1980).

Delaware Contact

InformationDelaware Department of Natural Resourcesand Environmental Controlwww.dnrec.state.de.us

DNREC Division of Soil and Water Conservation302-739-4411www.dnrec.state.de.us/dnrec2000/Divisions/Soil/Soil.htm

DNREC Shoreline and Waterway Management Section302-739-4411www.dnrec.state.de.us/dnrec2000/Divisions/Soil/ShorelineCons/Shoreline.htm

DNREC Delaware Coastal Programs Section302-739-3451www.dnrec.state.de.us/dnrec2000/Divisions/Soil/dcmp/index.htm

DNREC Division of Parks and Recreation302-739-4401www.destateparks.com

Additional Information on Coastal Issues

University of Delaware Sea Grant College Programwww.ocean.udel.edu

University of Delaware Center for Applied Coastal Researchwww.coastal.udel.edu

Delaware Geological Surveywww.udel.edu/dgs

American Shore and Beach Preservation Associationwww.asbpa.org/

U.S. Geological Survey Coastaland Marine Geology Programhttp://marine.usgs.gov

National Oceanic and Atmospheric Administration (NOAA)www.noaa.gov

Coastal Services Centerwww.csc.noaa.gov/

Marine Geology and Geophysics Divisionwww.ngdc.noaa.gov/mgg/mggd.html

Coast Survey Officehttp://chartmaker.ncd.noaa.gov/

Office of Ocean and Coastal Resource Managementwww.ocrm.nos.noaa.gov/

Office of Coastal Coastal Zone Managementwww.ocrm.nos.noaa.gov/czm/


This document was developed with funding from: (1) Delaware Department of NaturalResources and Environmental Control (DNREC), Division of Soil and Water Conservation,Shoreline & Waterway Management Section; and (2) DNREC Delaware Coastal Programs,pursuant to the Coastal Zone Management Act of 1972, as amended, administered by theOffice of Ocean and Coastal Resource Management, National Oceanic and AtmosphericAdministration Award No. NA17OZ2329.

Document No. 40-07-01/04/08/06

AcknowledgmentsPhotographs

Cover Inset: Kevin Fleming from The Beaches of Delaware and HistoricSussex County by Kevin Fleming (Portfolio Books, Rehoboth, DE, 1999).

Back Cover: Kevin Fleming from The Beaches of Delaware and HistoricSussex County by Kevin Fleming (Portfolio Books, Rehoboth, DE, 1999).

Historic Cape Henlopen photographs (Figure 31):1926: Delaware Air Photo Archive by John. E. Inkster.1968: Delaware Geological Survey Archives.1997: Delaware Department of Transportation.

1962 Storm Photos: Delaware Department of Transportation.

Figure 45: Shorebird (willet) inset, page 19: Rob Robinson.Figure 46: Piping plover, page 19: Jay Davis.Figure 47: Shorebirds, page 20: British Trust for Ornithology.Figure 48: Horseshoe crabs, page 20: Susan Love, Delaware

Coastal Programs.Figure 49: Horseshoe crabs and birds, page 20: DNREC,

Delaware Coastal Programs.Figure 50: Horseshoe crab eggs, page 21: DNREC Delaware Coastal Programs.Figure 51: Plover nest on beach, page 21: Jay Davis.Figure 52: Plover chick and eggs, page 21: Laune MacIvor, U.S. Fish and Wildlife Service.

Other photos by Wendy Carey, Evelyn Maurmeyer, and Tony Pratt.

Graphics

Figure 5: Adapted from Kraft, J. C., page 32, in The Delaware Estuary:Rediscovering a Forgotten Resource, eds. T. L. Bryant and J. R. Pennock(Newark, DE: University of Delaware Sea Grant College Program, 1988).

Figure 13: Adapted from Rogers, S. R., and D. Nash, page 3, inThe Dune Book, North Carolina Sea Grant Publication NumberUNC-SG-03-03 (NC State University, Raleigh, NC, 2003).

Figures 8, 15, 18, 22, 34, 67, 73: Adapted with permission fromoriginal Striking a Balance (1985) drawings by Karin Grosz.

Illustrations

All illustration sketches by Karin Grosz. Permission to reproduce theillustrations drawn for this book must be obtained from Karin Grosz.

Written by Wendy Carey, Evelyn Maurmeyer, and Tony Pratt.

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