Developing & Implementing Ecosystem Flow Recommendations for the Savannah River (GA/SC)

1. Developing & ImplementingEcosystem Flow Recommendationsfor the Savannah River (GA/SC)A Case Study under the Corps-TNCSustainable Rivers Project

2. Sustainable Rivers ProjectCurrent Sites Skagit West Green Ashuelot Roanoke Bill Williams Savannah White, Black, Little Red

3. Lower Savannah River and Estuary

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

5. Orientation MeetingMay 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

6. 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

7. Preparation of Summary Report(Nov 2002 - 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

8. Ecosystem Flow Workshop(April 2003)

9. 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

10. 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.

11. These would flood Augusta Savannah Flow Recommendations

13. Really?... Monitoring, Research, & Adaptive Management Key Wet Year Avg Year Dry Year Ecosystem Flow Recommendations Savannah River, below Thurmond Dam (River-Floodplain) • 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 Floods >30,000 cfs; 5 pulses, >2 days with 2 events of 2 week duration (March and early April) • 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 High Flow Pulses • <13,000 cfs; 3 successive years, every 10-20 years • Floodplain tree recruitment • 8,000-12,000 cfs; • Exchange water with oxbows Low Flows • >8,000 cfs • Larval drift for pelagic spawners • <5,000 cfs • Adequate floodplain drainage • Create shallow water habitat for small-bodied fish • 3,000 cfs; 3 successive years every 10-20 years • Floodplain tree recruitment JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

14. High Pulse Release(March 2004 )

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

16. Savannah RiverCase 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

17. Developing Environmental FlowsA Multi-Level Approach

18. Goal: (of the instream flow studies) is “to conserve biodiversity and maintain biological integrity.” -- TX Instream Flow Studies: Technical Overview, Aug 8, 03 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

19. 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

20. Developing Environmental FlowsA Multi-Level Approach 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

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

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

23. Developing Environmental FlowsA Four Level Approach • Level I: Hydrologic Desk Top Method • Level II: Experts Workshop • Level III: Detailed Instream Flow Studies • Level IV: Adaptive Refinement

24. Developing Environmental FlowsA Four Level Approach • Level I: Hydrologic Desk Top Method • Level II: Experts Workshop • Level III: Detailed Instream Flow Studies • Level IV: Adaptive Refinement

25. Level I, Characteristics • 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 • Apply Indicators of Hydrologic Alteration (IHA) software, Range of Variability Analysis

26. 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)

27. 1/3 “Bins”

30. Developing Environmental FlowsA Four Level Approach • Level I: Hydrologic Desk Top Method • Level II: Experts Workshop • Level III: Detailed Instream Flow Studies • Level IV: Adaptive Refinement

31. Level II, Characteristics • 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

32. Level II: Savannah

33. Developing Environmental FlowsA Four Level Approach • Level I: Hydrologic Desk Top Method • Level II: Experts Workshop • Level III: Detailed Instream Flow Studies • Level IV: Adaptive Refinement

34. Level III, Characteristics • 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

35. Developing Environmental FlowsA Four Level Approach • Level I: Hydrologic Desk Top Method • Level II: Experts Workshop • Level III: Detailed Instream Flow Studies • Level IV: Adaptive Refinement

36. Level IV, Characteristics • 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)

37. Developing Environmental FlowsSummary of a Four Level Approach • Relies on the best available science • Designed to incorporate new knowledge and understanding • Recognizes resource constraints • different situations require different resources

38. Developing Environmental FlowsA Four Level Approach • Level I: Hydrologic Desk Top Method • Level II: Experts Workshop • Level III: Detailed Instream Flow Studies • Level IV: Adaptive Refinement