San Pedro Riparian National Conservation Area St. David Cienega October 18, 2011 Mark Gonzalez

Understanding the Attributes and Processes that Constitute Riparian

Function within Wetland (Lentic) Systems

San Pedro Riparian National Conservation AreaSt. David CienegaOctober 18, 2011

Mark GonzalezNational Riparian Service Team

Outline: Function of Lentic Systems

I. What is a Lentic SystemII. HydrogeomorphologyIII. VegetationIV. SoilsV. Water QualityVI. Potential and Capability;

Sustainability and Trend

Lentic Systems

• Lentus (Latin) means sluggish

– Contrast “lotus,” past participle from “lavere,” meaning to wash; used for moving water systems

• Lentic denotes “still” water systems

• Lakes, ponds, sloughs, wet meadows, bogs, fens, marshes, swamps, vernal pools, springs, and cienegas

Evanson allotment, Sheyenne National Grassland, ND

HydrogeomorphologyPerched systems: surface-water source

Restrictive layer

Direction of water movementSaturated zone

Restrictive layer:(e.g., clay, silt)

Bedrock or basin fill

HydrogeomorphologyPerched systems: surface and ground water sources


Unsaturated zone

Impermeable layer


Impermeable layer

Groundwater discharge systems(groundwater dependent ecosystems)

Hydrogeomorphology

Water table

Direction of water movementWater table

Hydrogeomorphology

Water table


Groundwater pumping: Surface and Ground water connected• Cone of depression• Recharge rate vs. extraction rate

GW well

GW well

HydrogeomorphologyDisconnected ground and surface waters


Unsaturated zone

Impermeable layer


GW well

Inundation characteristics• Depth

Hydrogeomorphology

FAC-FACUFACWOBL

(em)AQUOpenWater

• Duration• Frequency

Fluctuations/Decline in Water TableHydrogeomorphology

• Survivorship • Establishment• Regeneration• Dormancy

• Net drop• Rate of decline• Seasonality

Capillary fringe

• Invasive species• Upland species• New fire regime

HydrogeomorphologyManagement Concerns• Altered Flow Patterns• Dewatering• Loss of riparian habitat West I allotment, Sheyenne

National Grassland, ND

East A allotment, Sheyenne National Grassland, ND

HydrogeomorphologyManagement Concerns• Dewatering -- loss/contraction of riparian

habitat

Pinedale Field Office, BLM, Wyoming

• Shade the ground• Trap sediment

Vegetation

Insert photo herbaceous shading in lentic area

Vegetation• Protect shorelines• Rooting strength

Williams allotment, Little Missouri National Grassland, ND

Allotment 1-4, Little Missouri Nat. Grassland, ND

Little Missouri National Grassland, ND

Loss of riparian sponge due to lack of protective shoreline vegetation

Vegetation: Drop in water table• Loss of riparian

vegetation• Loss of vigor• Invasion by upland

plants

Whitetail Cr., Little Missouri National Grassland, ND

Pinedale Field Office, BLM, Wyoming

• The SpongeSoils

Cobble-Gravel Sand Silt Clay

Porosity =

Hyd. Con. =

33%

2-20 m/day

33%

0.1-1 m/day

45%-60%

0.01-0.1 m/day

65%-90%0.001 - 0.01

m/day

Surface area (1g) = 0.01 m2, 5 m2, 150 m2

Soils• Depth to water

Winema NF, Oregon

Oi

Oe

NRCS, 2010

Army Corps of Engineers

SoilsEvidence of saturation• Aerobic/anaerobic conditions• pH/nutrient availability

Courtesy University of Idaho

Soils: Management Concerns• Alkalinity• pH

Smith Allotment, Grand River National Grassland, SD

Soils: Management Concerns• Compaction• Pedestalling• Dewatering

Pinedale Field Office, Wyoming

Sloping Wetland, central Nevada, by M. Manning

Carlson Slump, Idaho, by Steve Smith

Water Quality• Water Chemistry• Dissolved oxygen• Fecal coliform

• Suspended sediment

• Total sediment

• Industrial waste• Point-source pollution• Waste-treatment plants• Nitrification

Water Quality

PFC PNC

Values

Tim

e

NF FAR

Recreation / Birding

Watershed Values

Livestock Values

Fisheries / Wildlife

DFC?

Decision Space


Unsaturated zone

Impermeable layer


Potential: greatest condition possible w/no constraints

Capability: best possible condition given political, social, and economic constraints (i.e., limiting factors)

• Degree of Alteration?• Sustainable? • PFC = Sustainable


Unsaturated zone

Impermeable layer


Potential and Capability

• Degree of Alteration?• Sustainable?


Unsaturated zone

Impermeable layer



Former water surface

Potential and Capability• Does the change matter? How much change is too much?

– E.g., Southwestern Willow Flycatcher habitat?

Width

Width

• Does change matter? …For a Spike dace, speckled dace, or Gila chub?



Water table


GW well


Former water table

SPRNCA (federal public lands)

Privatelands

GW well


Water table



Former water table

SPRNCA (federal public lands)

Privatelands

GW well

Potential and CapabilityWhat if incision was due to natural event?…Or human activity (e.g., artificial drainage)?


Unsaturated zone

Impermeable layer


Impermeable layer

Summary

• Assessments of lentic systems based on:– Hydrogeomorphic attributes and processes;

(Water sources, amount, depth, duration, frequency)

– Vegetational attributes and processes;(Type, diversity, age distribution, root strength/stability, adaptation to saturation and anaerobic conditions)

– Soil attributes and processes;(Saturation, water retention, chemistry)

Summary

• Management Concerns– Alteration of hydrologic cycle– Alteration of water quantity

• Surface and groundwater withdrawals• Minimum stream flows• Water rights

– Vegetation vigor, type, and extent– Soil compaction, pedestalling, and

dewatering

Summary

• Potential and Capability– Potential is best possible condition– Proper functioning is minimum acceptable

condition for long-term sustainability– Have current activities changed potential?– Do current activities affect sustainability?

San Pedro Riparian National Conservation Area St. David Cienega October 18, 2011 Mark Gonzalez

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