Environmental Flows Eric S. Hersh CE397 November 10, 2005 (National Geographic)
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Transcript of Environmental Flows Eric S. Hersh CE397 November 10, 2005 (National Geographic)
Environmental FlowsEnvironmental Flows
Eric S. HershEric S. HershCE397CE397
November 10, 2005November 10, 2005
(National Geographic)
(USFWS, 2005)
(CSIRO, 2003)
(M.Bogan, Oregon State U)
topical developmenttopical development
dams and reoperation
Elaine, Andrew
environmental flows (science)
Eric, Becky
water reserve (policy)
Shane, Tyler
environmental flow definitionenvironmental flow definition
Water left in or released into a river system, often Water left in or released into a river system, often for managing some aspect of its conditionsfor managing some aspect of its conditions Endangered species protectionEndangered species protection Healthy ecosystemHealthy ecosystem Sediment transportSediment transport Commercial fisheries yieldCommercial fisheries yield Freshwater inflows to bays and estuariesFreshwater inflows to bays and estuaries Waste assimilationWaste assimilation
environmental flow requirementsenvironmental flow requirements
Flows to sustain or restore the Flows to sustain or restore the ecological functionsecological functions (goods and services) of a river(goods and services) of a river
Fish and wildlife: habitat, migration, reproduction, biodiversityFish and wildlife: habitat, migration, reproduction, biodiversity RecreationRecreation NavigationNavigation HydropowerHydropower Waste assimilationWaste assimilation Water supplyWater supply Food supplyFood supply Flood and drought mitigationFlood and drought mitigation Nutrient deliveryNutrient delivery Coastal salinity regulationCoastal salinity regulation
interdisciplinary natureinterdisciplinary nature
Engineering: hydrology, hydraulics, water qualityEngineering: hydrology, hydraulics, water quality
Biology and ecologyBiology and ecology
Geomorphology and physical processesGeomorphology and physical processes
Policy and regulationPolicy and regulation
international natureinternational nature
Basin-wide management scaleBasin-wide management scale
Transboundary difficulties in prescribing and Transboundary difficulties in prescribing and regulating environmental flow needsregulating environmental flow needs
Disparities in water availability and need, Disparities in water availability and need, infrastructure, technical capacity, environmental infrastructure, technical capacity, environmental awareness, regulatory structureawareness, regulatory structure
human impacthuman impact
(USBR, 2004)
historic river resource protectionhistoric river resource protection Water qualityWater quality
U.S. Clean Water Act, 1972U.S. Clean Water Act, 1972 Designated uses, water quality criteriaDesignated uses, water quality criteria ““The objective of this Act is to restore and maintain the The objective of this Act is to restore and maintain the
chemical, physical, and biological integrity of the chemical, physical, and biological integrity of the Nation’s waters”Nation’s waters”
Water quantityWater quantity Minimum flow (flat line)Minimum flow (flat line) “…“…nothing in this Act shall be construed to supersede nothing in this Act shall be construed to supersede
or abrogate rights to quantities of water which have or abrogate rights to quantities of water which have been established by any State.”been established by any State.”
flow- “the master variable”flow- “the master variable”
Controlling factor in riverine Controlling factor in riverine physical, biological, and physical, biological, and chemical processeschemical processes
e.g.: water temperature, e.g.: water temperature, dissolved oxygen, available dissolved oxygen, available habitat, spawning cues, channel habitat, spawning cues, channel shape, substrate type, etcshape, substrate type, etc
Question: manage flow for…?Question: manage flow for…?
Answer: Answer: everyoneeveryone..the natural flow regimethe natural flow regime
(Postel and Richter, 2003)
Poff et al 1997
the natural flow regimethe natural flow regime
MagnitudeMagnitude
FrequencyFrequency
DurationDuration
TimingTiming
Rate of change of hydrologic eventsRate of change of hydrologic events
characterizing streamflowcharacterizing streamflow
Subsistence flowSubsistence flow Water quality (temperature, DO, waste Water quality (temperature, DO, waste
assimilation)assimilation) Riparian plant recruitmentRiparian plant recruitment Purge invasive speciesPurge invasive species
Base flowBase flow Dominant flow condition in many riversDominant flow condition in many rivers Determines available habitatDetermines available habitat
Maidment et al 2005
characterizing streamflowcharacterizing streamflow Flow pulsesFlow pulses
Within banksWithin banks Macrophyte growth/SOD controlMacrophyte growth/SOD control Nutrient and organic matter deliveryNutrient and organic matter delivery Shape the river channel geometryShape the river channel geometry Longitudinal connectivityLongitudinal connectivity
Flood flowsFlood flows OverbankOverbank Lateral connectivityLateral connectivity Riparian plant germinationRiparian plant germination ““Food bazaar”Food bazaar”
Maidment et al 2005
human impacthuman impact
Artificial higher or lower low flowsArtificial higher or lower low flows
Erratic daily flows from hydropower demandErratic daily flows from hydropower demand
Prevent or minimize floodsPrevent or minimize floods
Disconnect floodplain Disconnect floodplain
Channelize rivers and alter lotic habitatChannelize rivers and alter lotic habitat
Erase life cycle flow cuesErase life cycle flow cues
Eliminate variabilityEliminate variability
human impacthuman impact
(Postel and Richter, 2003)
How much How much water does water does
a river a river need?need?
the big question…the big question…
water allocationwater allocation2020thth century century
2121stst century century
what is this sustainable boundary?
Ecosystem support allocationEcosystem support allocation
(Postel and Richter, 2003)
quantifying environmental flowsquantifying environmental flows
1950s-present1950s-present
South Africa, Australia, United StatesSouth Africa, Australia, United States
Hydrologic (Desktop) ModelsHydrologic (Desktop) Models
Hydraulic ModelsHydraulic Models
Habitat ModelsHabitat Models
Holistic ModelsHolistic Models
quantifying environmental flowsquantifying environmental flows
Hydrologic (Desktop) ModelsHydrologic (Desktop) Models Simple, cheap, easySimple, cheap, easy Use flow as an indicator for ecological and biological Use flow as an indicator for ecological and biological
functionsfunctions
Examples:Examples: Indicators of Hydrologic Alteration (IHA), The Nature Indicators of Hydrologic Alteration (IHA), The Nature
Conservancy, 1997Conservancy, 1997 Tennant Method (a.k.a. Montana Method), U.S. Fish Tennant Method (a.k.a. Montana Method), U.S. Fish
and Wildlife Service, 1976and Wildlife Service, 1976 Lyons Method, Texas Parks and Wildlife Dept., 1979.Lyons Method, Texas Parks and Wildlife Dept., 1979.
quantifying environmental flowsquantifying environmental flows
Hydraulic ModelsHydraulic Models Correlate flow with available habitat area based on Correlate flow with available habitat area based on
river channel geometryriver channel geometry Physical proxy for Physical proxy for in-streamin-stream ecology and biology ecology and biology
Examples:Examples: Wetted Perimeter Method, Montana Dept. of Fish, Wetted Perimeter Method, Montana Dept. of Fish,
Wildlife, and Parks, 1970sWildlife, and Parks, 1970s R2-Cross Method, Colorado Div. of Wildlife, 1980sR2-Cross Method, Colorado Div. of Wildlife, 1980s
quantifying environmental flowsquantifying environmental flows
Habitat ModelsHabitat Models Complex, data intensiveComplex, data intensive Use target species population data with hydraulic Use target species population data with hydraulic
data to determine optimal habitatdata to determine optimal habitat
Examples:Examples: Instream Flow Incremental Methodology (IFIM), Instream Flow Incremental Methodology (IFIM),
U.S. FWS, 1970s. Includes Physical Habitat U.S. FWS, 1970s. Includes Physical Habitat Simulation Model (PHABSIM). Mainly used for Simulation Model (PHABSIM). Mainly used for economically valuable or endangered species; economically valuable or endangered species; legal credibility.legal credibility.
quantifying environmental flowsquantifying environmental flows
Holistic ModelsHolistic Models Very complex, resource and data intensiveVery complex, resource and data intensive Comprehensive ecosystem assessmentComprehensive ecosystem assessment
Examples:Examples: Building Block Methodology (BBM), South Africa Building Block Methodology (BBM), South Africa
Dept. of Water Affairs and Forestry and Univ. of Dept. of Water Affairs and Forestry and Univ. of Cape Town, 1990s. Top-down approach.Cape Town, 1990s. Top-down approach.
Downstream Response to Imposed Flow Downstream Response to Imposed Flow Transformation (DRIFT), above plus Southern Transformation (DRIFT), above plus Southern Waters Ecological Research and Consulting, 1990sWaters Ecological Research and Consulting, 1990s
issues in quantifying issues in quantifying environmental flowsenvironmental flows
ScalingScaling
Ecological indicatorsEcological indicators
IntegrationIntegration
Data and resource availabilityData and resource availability
Legal/regulatory statusLegal/regulatory status
natural flow regime restorationnatural flow regime restoration
(Postel and Richter, 2003)
implementationimplementation
(Postel and Richter, 2003)
Dam reoperationDam reoperation
Dam removalDam removal
Controlled floodsControlled floods
Adaptive managementAdaptive management
dam removaldam removal
(GZA GeoEnvironmental, 2000)Old Berkshire Mill DamE. Branch Housatonic River, Massachusetts
dam removaldam removal
(E.Hersh, 2003)
Livermore Pond DamEaston, Connecticut
dam removaldam removal
Livermore Pond DamEaston, Connecticut
questions for discussionquestions for discussion
How much water does a river need? Can this How much water does a river need? Can this really be determined? How?really be determined? How?
What tools can be used to demonstrate the need What tools can be used to demonstrate the need for and value of environmental flows?for and value of environmental flows?
What instruments can be used to implement What instruments can be used to implement environmental flow prescriptions?environmental flow prescriptions?