Developing & Implementing Ecosystem Flow Recommendations for the Savannah River (GA/SC) A Case Study under the Corps-TNC Sustainable Rivers Project

Skagit Green Roanoke Bill Williams Savannah White, Black, Little Red Sustainable Rivers Project Current Sites Ashuelot West

Lower Savannah River and Estuary

May 2002 April 2003 Oct Feb 2003 March 2004 (initial) Ongoing Developing & Implementing Ecosystem Flow Recommendations Savannah River (GA/SC)

Orientation Meeting May 2002 Purpose: Launch a collaboration to collect and apply our best knowledge on flow-ecological process relationships to water management Invitees: Agencies, NGO’s, University Researchers, SREL Outcome: Designed a process and identified key contributors for defining a set of essential flow characteristics needed to sustain the ecological integrity of the Savannah River ecosystem

Preparation of Literature Review (Oct - Nov, 2002) Conduct a literature review of sources that appear useful in informing ecosystem flow recommendations (Savannah and similar systems) Focus on the whole ecosystem, including the shoals, river- floodplain, and estuary Review for completeness by leading scientists in each of the three component areas

Preparation of Summary Report (Nov Feb 2003) key findings about linkage between specific ecological flow components and biotic tolerances or dependencies pictorial models illustrating connection between natural hydrographs and life cycles of representative species box-and-arrow diagrams expressing relationships between ecological flow components and biotic responses or dynamics. Reviewed by leading scientists in the three component areas

Ecosystem Flow Workshop (April 2003)

Workhop: 2½ days, >40 scientists (agencies, academics and NGO’s) Three break-out groups defined ecological flow recommendations for: (i) Augusta shoals; (ii) river-floodplain section from Augusta shoals to estuary; and, (iii) estuary  Low Flows, High Flow Pulses, Floods Full group integrated flow recommendations across the 3 river reaches Report generated; reviewed by all workshop participants

The goal is not to create optimal conditions for all species all of the time; rather, we want to create adequate conditions for all native species enough of the time.

These would flood Augusta Savannah Flow Recommendations

JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC Ecosystem Flow Recommendations Savannah River, below Thurmond Dam (River-Floodplain) Low Flows High Flow Pulses Floods 3,000 cfs; 3 successive years every years Floodplain tree recruitment <5,000 cfs Adequate floodplain drainage Create shallow water habitat for small-bodied fish >8,000 cfs Larval drift for pelagic spawners 50,000-70,000 cfs; 2 weeks, avg every 2 yrs Maintain channel habitats Create floodplain topographic relief Provide fish access to the floodplain control invasive species Maintain wetlands and fill oxbows and sloughs Enhance nutrient cycling & improve water clarity Disperse tree seeds <13,000 cfs; 3 successive years, every years Floodplain tree recruitment 8,000-12,000 cfs; Exchange water with oxbows 20,000-40,000 cfs; 2-3 days, 1/month Provide predator-free habitat for birds Disperse tree seeds Transport fish larvae Flush woody debris from floodplain to channel Floodplain access for fish Fish passage past NSBLD >30,000 cfs; 5 pulses, >2 days with 2 events of 2 week duration (March and early April) Key Dry Year Avg Year Wet Year Really?... Monitoring, Research, & Adaptive Management

High Pulse Release (March 2004 )

May 2002 April 2003 Oct Feb 2003 March 2004 (initial) Ongoing Steps for Developing Ecosystem Flow Recommendations Savannah River (GA/SC)

Savannah River Case Study Summary Collaborated to define ecosystem flows: –done for the whole system (shoals, river-floodplain, estuary) –applied best available science –completed in one year, for $90K Developing a strategic monitoring plan to assess dam re-operation and inform future management Modeling to assess multiple future scenarios

Developing Environmental Flows A Multi-Level Approach

It’s recognized that... River flow is a “master variable” for maintaining the integrity of freshwater ecosystems Healthy freshwater ecosystems: –require that some semblance of the full range of natural flow variability be maintained –degrade the more we alter natural flow patterns Goal: (of the instream flow studies) is “to conserve biodiversity and maintain biological integrity.” -- TX Instream Flow Studies: Technical Overview, Aug 8, 03

Developing Environmental Flows Challenges Include: –identifying what components of flow are ecologically most critical in a particular river system –quantifying those flow components to help guide water management –incorporating new knowledge and understanding into water management over time –achieving these tasks for all rivers within resource constraints

The Common Denominator Low Flows – Determine the amount of habitat available, necessary energy expenditures. High Flow Pulses – Open up additional habitat area, bring additional food material from upstream areas, moderate temperatures and oxygen levels, clean spawning gravels, and provide cues for migration to spawning areas Floods – Create the physical template of the river ecosystem, including formation of oxbows (backwaters) and secondary channels, floodplains, and spawning bars, and keep introduced species populations in check Developing Environmental Flows A Multi-Level Approach

From “Rivers for Life: Managing Water for People and Nature” by Sandra Postel and Brian Richter (Island Press 2003)

Low Flows, High Flow Pulses, Floods magnitude, frequency, duration, timing, rate of change åApproach: Systematic process to develop and incrementally refine environmental flows Developing Environmental Flows A Multi-Level Approach

Level I: Hydrologic Desk Top Method Level II: Experts Workshop Level III: Detailed Instream Flow Studies Level IV: Adaptive Refinement Developing Environmental Flows A Four Level Approach

Level I: Hydrologic Desk Top Method Level II: Experts Workshop Level III: Detailed Instream Flow Studies Level IV: Adaptive Refinement

Very quick and inexpensive (least rigorous) Consider as a placeholder (for Levels II or III) Uses hydrologic data only Uses low flows, high flow pulses, floods Level I, Characteristics åApply Indicators of Hydrologic Alteration (IHA) software, Range of Variability Analysis

Indicators of Hydrologic Alteration (IHA) Statistical program Tool for analyzing hydrologic characteristics and changes in those characteristics over time Presents flow and flow alteration in ecologically meaningful terms…  low flows, high flow pulses, and flood flows (magnitude, timing, frequency, duration, rate of change)

1/3 “Bins”

Developing Environmental Flows A Four Level Approach Level I: Hydrologic Desk Top Method Level II: Experts Workshop Level III: Detailed Instream Flow Studies Level IV: Adaptive Refinement

Modest time and money required (moderate rigor) Relies on hydrologic data, existing ecological research, and best professional judgement of experts Can be supplemented with a literature review and summary report Uses low flows, high flow pulses, floods Level II, Characteristics

Level II: Savannah

Developing Environmental Flows A Four Level Approach Level I: Hydrologic Desk Top Method Level II: Experts Workshop Level III: Detailed Instream Flow Studies Level IV: Adaptive Refinement

Expensive and time consuming (most rigorous) Relies on hydrologic data, existing ecological research, additional research fieldwork, and modeling (and best professional judgement of experts) Uses low flows, high flow pulses, floods Level III, Characteristics

Developing Environmental Flows A Four Level Approach Level I: Hydrologic Desk Top Method Level II: Experts Workshop Level III: Detailed Instream Flow Studies Level IV: Adaptive Refinement

Operational mode rather than a separate “Level” Improves input to decision making Acknowledges uncertainty (even in Level III) Requires monitoring, with periodic review and refinement as needed (~5 years) Level IV, Characteristics

Relies on the best available science Designed to incorporate new knowledge and understanding Recognizes resource constraints –different situations require different resources Developing Environmental Flows Summary of a Four Level Approach

Level I: Hydrologic Desk Top Method Level II: Experts Workshop Level III: Detailed Instream Flow Studies Level IV: Adaptive Refinement Developing Environmental Flows A Four Level Approach