Dr. Eloise Kendy Director, Environmental Flows Program The Nature Conservancy

nutrient cycling ELOHA: A New Framework for Determining and Managing Environmental Flows Over Large Regions Dr. Eloise Kendy Director, Environmental Flows Program The Nature Conservancy March 2009 Do not reproduce any photos that are in this presentation.

Healthy ecosystems have evolved in response to natural flow variations. TRINITY RIVER, CALIFORNIA, USA

Environmental Flow:The flow of water in a natural river or lake that sustains healthy ecosystems and the goods and services that humans derive from them. Water for People, Water for Nature

Environmental Flow Ecologically defined Entire river community Patterns of flow

Setting Limits: Defining environmental flows Postel and Richter, 2003

Criteria for a Regional Environmental Flow Method Addresses many rivers simultaneously Explicitly links flow and ecology Applies across a spectrum of: Flow alteration types Data availability and scientific capacity Social and political contexts

Quantifies trade-offs between streamflow alteration and ecological degradation Informs the determination of environmental flow targets Integrates environmental flows into a computerized DSS Ecological Limits of Hydrologic Alteration (ELOHA)

Ecological Limits of Hydrologic Alteration (ELOHA) A framework for integrating environmental flows into regional water planning and management

Flow Alteration - Ecological Response Curve

SCIENTIFIC PROCESS Step 1. Hydrologic Foundation Step 2. Stream Classification Baseline Hydrographs Stream Hydrologic Classification Geomorphic Stratification Hydrologic Model and Stream Gauges Step 3. Flow Alteration Degree of Hydrologic Alteration Hydrologic Alteration by River Type Developed Hydrographs Monitoring Step 4. Flow-Ecology Relationships Flow Alteration-Ecological Response Relationships by River Type Flow - Ecology Hypotheses Ecological Data and Indices SOCIAL PROCESS Societal Values and Management Needs Environmental Flow Standards Implementation Acceptable Ecological Conditions Adaptive Adjustments

Hydrologic Foundations Michigan Water Withdrawal Assessment Tool Colorado DSS, Watershed Flow Evaluation Tool CALSIM, Sacramento Ecological Flows Tool Virginia’s OASIS, HSPF Texas Water Availability Model (WAM)

Step 1 Streamflow database Hydrologic Foundation Measured baseline hydrographs Measured developed-condition hydrographs Hydrologic model Basin characteristics, climate database Water use database Baseline hydrographs for all control points Developed-condition hydrographs for all control points River classification

Step 2 River Classification Hydrology-based Define flow-ecology response curves for types of rivers MICHIGAN, USA Seelbach et al

River Classification New Jersey, USA USGS Hydroecological Integrity Assessment Process (HIP) Kennen et al (2007)

New Jersey River Classification USGS Hydroecological Integrity Assessment Process (HIP) Kennen et al (2007)

Geomorphic Sub-Classification Snohomish River basin, USA Higgins et al (2003)

Step 1 Streamflow database Hydrologic Foundation Measured baseline hydrographs Measured developed-condition hydrographs Hydrologic model Basin characteristics, climate database Water use database Baseline hydrographs for all control points Developed-condition hydrographs for all control points River classification Analysis of hydrologic alteration

Step 3 Compute Hydrologic Alteration SELECTING HYDROLOGIC METRICS Criteria Strongly linked to ecological condition Amenable for use as water management targets Examples Timing of flood peaks Duration of zero-flow period Percent of August flow diverted

Step 3 Compute Hydrologic Alteration ENVIRONMENTAL FLOW COMPONENTS Output from TNC’s IHAsoftware Large flood High flow pulse Small flood Streamflow (cfs) Extreme low flow Low flow Day of Year Magnitude, frequency, duration, timing, rate of change For each:

Step 3 Compute Hydrologic Alteration Output from The Nature Conservancy’s Indicators of Hydrologic Alteration (IHA)software

Biotic indicator Hydrologic alteration SCIENTIFIC PROCESS Step 1. Hydrologic Foundation Step 2. Stream Classification Baseline Hydrographs Stream Hydrologic Classification Geomorphic Stratification Hydrologic Model and Stream Gauges Step 3. Flow Alteration Degree of Hydrologic Alteration Hydrologic Alteration by River Type Developed Hydrographs Monitoring Step 4. Flow-Ecology Relationships Flow Alteration-Ecological Response Relationships by River Type Flow - Ecology Hypotheses Ecological Data and Indices SOCIAL PROCESS Societal Values and Management Needs Environmental Flow Standards Implementation Acceptable Ecological Conditions Adaptive Adjustments

Step 4 Flow Alteration- Ecological Response Relationships FLOW-ECOLOGY HYPOTHESIS INVERTEBRATE RICHNESS or BIOMASS Decreasing 0 Increasing FREQUENCY OF SMALL FLOODS

Flow-Ecology Hypothesis – Verde River, Arizona Haney et al (2008)

Step 4 Flow - Ecology Response Curves ECOLOGICAL DATA COMPILATION Criteria Sensitive to existing or proposed flow alteration Can be validated with monitoring data Are valued by society Examples Aquatic invertebrate species richness Riparian vegetation recruitment Larval fish abundance

Flow - Ecology Response Curves Species cover vs. flow permanence SAN PEDRO RIVER, ARIZONA, USA Stromberg et al (2005)

Approaches for Setting Ecological Goals • All rivers have the same goal • Stakeholders set the goal – Michigan, USA • Government sets the goal – European Union • 2. Different classes of rivers have different goals • Stakeholders classify the rivers – South Africa • Government classifies the rivers – Connecticut, USA • 3. Each river has its own unique goal • Stakeholders set the goals – Texas, USA • Government sets the goals – Australia

Ecological Goal Classes CONNECTICUT, USA Class 1 – Natural Class 2 – Near Natural Class 3 – Ecologically Sufficient Class 4 – Ecological Non-Attainment Waters MAINE, USA Class AA – Outstanding natural resource for preservation Class A – Habitat for fish and other aquatic life is natural Class B – Habitat for fish and other aquatic life is unimpaired Class C – Habitat for fish and other aquatic life exists

Step 1. Step 2. Determine acceptable ecological conditionsDefine environmental flow targets Michigan’s Screening Tool for Ground-Water Withdrawals 1.0 0.9 - 0.8 - 0.7 - 0.6 - 0.5 - 0.4 - 0.3 - 0.2 - 0.1 - 0.0 Characteristic species Proportion of initial fish population metric ECOLOGICAL CONDITION Adverse resource impact 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Proportion of index flow removed ENVIRONMENTAL FLOW STANDARD

Implementing Environmental Flow Targets Protection Dam siting and operation Permit system for withdrawals River basin management Restoration Dam re-operation Conjunctive ground- / surface-water use Drought management planning Demand management (conservation) Water transactions Moving diversion points

Hydrologic Foundation Comprehensive Water Resource Management Tool Streamflow database Water use database Basin characteristics, climate database Hydrologic model Climate change Integrated water management Hydrographs for all control points Population growth Infrastructure upgrade Analyses Environmental flow targets

State, Provincial, or National Government Streamflow and water-use data Ecological data Local Communities Hydrologic model Ecological goals Flow-ecology response relationships Environmental flow standards Implementation Assessment e-DSS Permit system and reservoir operating rules

Confidence in Protecting Healthy Rivers Studies TIME AND MONEY INVESTED High Experts Medium Low Literature River Type Single River Entire Country

nutrient cycling For further information: Dr. Eloise Kendy Director, Environmental Flows Program The Nature Conservancy ekendy@tnc.org http://conserveonline.org/workspaces/eloha

Dr. Eloise Kendy Director, Environmental Flows Program The Nature Conservancy