Water Resources and Water PollutionChapter 9

Water ResourcesWater Earths surface is covered by 71% waterEssential for life can survive only a few days without water

Supply of Water ResourcesSmall fraction (.014%) is readily available for human use

Water Cycle continuously collected, purified, recycled and distributed

WatershedA watershed describes the total area contributing drainage to a stream or riverMay be applied to many scalesA large watershed is made up of many small watersheds

Chehalis Basin

Zone of saturation (spaces completely filled with water)

Water sourcesSurface runoff 2/3 lost to floods and not available for human use.Reliable runoff = one thirdAmount of runoff that we can count on year to yearGroundwaterZone of saturationWater table top of zone of saturationAquifer water saturated layers of sand, gravel or bedrock through which groundwater flows.Recharge slow ~ 1 meter per year

Use of Water ResourcesHumans directly or indirectly use about 54% of reliable runoffWithdraw 34% of reliable runoff for:Agriculture 70%Industry 20%Domestic 10%

Leave 20% of runoff in streams for human use:transport goods, dilute pollution, sustain fisheriesCould use up to 70-90% of the reliable runoff by 2025

Too Little WaterProblems in the WestDry climateDrought DesiccationUS has plenty of water.Much of it is in the wrongplace at the wrong time.Most serious problems areflooding, pollution, occassional urban shortages

Water conflicts: Western USWater andFish

Water conflicts: GlobalTwo main factors for water shortage: dry climate and too many people. Many people live in hydro poverty cant afford cleanwater.

Too Much Water: FloodsNatural phenomenaAggravated by human activitiesRain on snowLiving on floodplainsImpervious surfacesRemoval of vegetationDraining wetlands

Deforestation and flooding

Using Dams and Reservoirs to Supply More Water: The Trade-offs

Tapping GroundwaterYear-round useNo evaporation lossesOften less expensivePotential Problems:Water table lowering too much useDepletion U.S. groundwater being withdrawn at 4X its replacement rateSaltwater intrusion near coastal areas Chemical contaminationReduced stream flows

Reducing water wasteread section 9-4

SolutionsSustainable Water UseNot depleting aquifersPreserving ecological health of aquatic systemsPreserving water qualityIntegrated watershed managementAgreements among regions and countries sharing surface water resourcesOutside party mediation of water disputes between nationsMarketing of water rightsRaising water pricesWasting less waterDecreasing government subsides for supplying waterIncreasing government subsides for reducing water wasteSlowing population growth

Pollution Source terminologyPoint source = pollution comes from single, fixed, often large identifiable sources smoke stacksdischarge drainstanker spillsNon-point source = pollution comes from dispersed sourcesagricultural runoffstreet runoff

Types of Water Pollutionfrom Table 9-1 p. 187Sediment logging, roadbuilding, erosionOxygen-demanding wasteshuman waste, storm sewers, runoff from agriculture, grazing and logging, many othersNutrient enrichment = EutrophicationN, P from fertilizers, detergentsleads to increased growth in aquatic systems, ultimately more non-living organic matter

BODAs micro-organisms decompose (through respiration) organic matter, they use up all the available oxygen.Biological Oxygen Demand (BOD) Amount of oxygen required to decay a certain amount of organic matter.If too much organic matter is added, the available oxygen supplies will be used up.

EutrophicationEutrophic well-fed, high nutrient levels present in a lake or river

Oligotrophic poorly-fed, low nutrient levels

Water bodies can be naturally eutrophic or oligotrophic, but can also be human-caused

Types of Water Pollution (cont)from Table 9-1 p. 187Disease-causing organismsfrom untreated sewage, runoff from feed lotsToxic chemicals pesticides, fertilizers, industrial chemicalsHeavy metals lead, mercuryAcids (to discuss later)Elevated temperatures = Thermal Pollution water is used for cooling purposes, then heated water is returned to its original sourceany increase in temperature, even a few degrees, may significantly alter some aquatic ecosystems.

Groundwater PollutionAgricultural productsUnderground storage tanksLandfillsSeptic tanksSurface impoundments

Oil SpillsExxon Valdez released 42 million liters of oil in Prince William Sound, contaminating 1500 km of Alaska coastline in 1989Was the cleanup effective?Most marine oil pollution comes from non-point sources: runoff from streetsimproper disposal of used oildischarge of oil-contaminated ballast water from tankers

Growth of population Supply & demand are in growing conflict supply is finite water management driven by values and needsIncreases demand/use of waterIncreases land use and changes vegetation and permeabilityIncreases demand for instream values instream flows are for people

The construction of dams haveslowed the once flowing ColumbiaRiver into a series of lakes.

Agriculture uses approximately 70% of the water withdrawn from our streams and rivers

Changing land use changes vegetation and need for water

Change in land use also changes permeability

Water RightsWater collectively belongs to the publicCannot be owned by individualsIndividuals or groups may be granted rights to use waterLegal authorization to use a predefined quantity of public water for a designated purpose.Irrigation, domestic water supply, power generation

Water RightsState law requires certain users of public waters to receive approval from the state prior to using water.Any use of surface water which began after 1917 requires a water-right permit.Withdrawals of underground water from 1945 requires a water-right permit.

Instream flows Result the more we know about stream ecology, the more we realize that all the water has instream value, meaning there is no surplus Compromises and minimizing impact thresholds for rate of impactOther ways to achieve ecosystem goals wider view, not just flows watershed land management

Legal/political aspects of instream flowprovide a flow of water sufficient to adequately support food fish and game fish populations in the stream (RCW 77.55.050)provide protection and preservation and where possible enhancement, of wildlife, fish, and other environmental values (RCW 90.54)protect fish, game, birds, and other wildlife, recreational and aesthetic values and water quality (RCW 90.22)antidegradation requirements of Washingtons water quality standards (Ch. 173-201 A WAC, following Federal Clean Water Act)

Instream flows Other ways to achieve ecosystem goals wider view, not just flows watershed land managementAvoid headwater disturbanceVegetationGeology and topographyMaintain longitudinal and lateral connectivityAvoid mainstem in-channel storage Allow floodplain to function as floodplain

Avoid headwater disturbance and leave vegetation

Allow floodplains to function as floodplains

Flow restoration Markets and transfersNeed to protect restored flows Enforcement

Opportunities Parks and wilderness areasRenewable natural resource management and harvest (forestry, grazing, secondary forest products)Municipal watershed protectionLow intensity sustainable agriculture

Watershed PlanningThe 1998 legislature passed ESHB 2514, codified into Ch. 90.82 RCW, to set a framework for developing local solutions to watershed issues on a watershed basis. Ch. 90.82 RCW states: The legislature finds that the local development of watershed plans for managing water resources and for protecting existing water rights is vital to both state and local interests.

Watershed PlanningRCW 90.82.005Purpose.The purpose of this chapter is to develop a more thorough and cooperative method ofdetermining what the current water resource situation is in each water resource inventory area of thestate and to provide local citizens with the maximumpossible input concerning their goals and objectives forwater resource management and development.

Watershed PlanningEach implementation plan must contain strategies to provide sufficient water for: (a) Production agriculture; (b) commercial, industrial, and residential use; and (c) instream flows. Each implementation plan must contain timelines to achieve these strategies and interim milestones to measure progress

*Areas with 15 to 75 percent impervious surface are characterized as moderately developed. Areas with greater than 75 percent impervious surface are considered urban or highly developed. Areas with greater than 10% impervious surface have been proven to have a negative affect on groundwater and stormwater.