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POTOMAC RIVER FLOWBY WORKSHOP: Introduction. OUTLINE OF PRESENTATION. Background Review of 1981 flow-by study Objectives of new flowby study Objectives of workshop. BACKGROUND. Current agreement: 100 mgd below Little Falls Dam 300 mgd recommendation below Great Falls to Little Falls Dam.
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OUTLINE OF PRESENTATION • Background • Review of 1981 flow-by study • Objectives of new flowby study • Objectives of workshop
BACKGROUND • Current agreement: 100 mgd below Little Falls Dam • 300 mgd recommendation below Great Falls to Little Falls Dam
Study Required by Low-Flow Allocation Agreement (LFAA) • Signatories: COE-WAD, MD, VA, DC, FCWA, WSSC • Augmentation releases determined and requested by ICPRB
REVIEW OF 1981 STUDY • 1981 study itself and others identified shortcomings • 100/300 mgd flow-by not environmentally based (or if so, not documented) • “ A daily average flow below Little Falls Dam of 100 mgd is nearly the limit of what the current system can provide during extreme drought conditions...” • Lowest measured flow for the 1981 study was 900 mgd (1400 cfs)
REVIEW OF 1981 STUDY, cont. • 1999 drought prompted reconsideration of the flow-by issues • Habitat Assessment Subcommittee (HAS), subset of the Potomac River Flow-By Evaluation Committee organized to revisit 1981 study dueto shortcomings and new information
CURRENT OBJECTIVES SHORT-TERM • Estimate the amount and quality of biotic habitat available at different flow levels, particularly as it relates to the current minimum flow-by requirement,
CURRENT OBJECTIVES LONG-TERM • Determine what instream flows are required to provide adequate aquatic habitat and to prevent a reduction of any representative important species beyond levels from which it cannot recover and re-colonize the area following a drought event.
WORKSHOP STRUCTURE • Assemble experts in riverine habitat assessment to advise the Subcommittee on the best means of achieving the Potomac Flow-by Study objectives. • Experts to present and discuss their views on the best means of addressing the objectives. • Experts to recommend the best analysis techniques and related data collection considerations for our specific situation: • Extreme & infrequent drought conditions
WORKSHOP PURPOSE • Assess methodologies to evaluate flow-by requirements of the Potomac River to provide the following recommendations to the Habitat Assessment Committee: • The most favorable methodology, given current financial resource limitations, to address the Potomac River Flow-by Study objectives; and • An alternative long-term methodology that could better accomplish those objectives, yet might exceed current resources or available data, and recommended guidelines for achieving the objectives in a longer time-frame.
FUTURE DIRECTIONS • Workshop summary report including panel recommendations • Report distributed for comment • Final report to Habitat Assessment Subcommittee (HAS) • HAS recommendation to full Potomac Flow-by Committee for further action