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MA BF REFERENCE CURVES. Objective Develop bankfull regional curves and equations for estimating bankfull width, mean depth, cross-sectional area, and discharge in Massachusetts. BF REFERENCE STREAMGAGES. USGS streamflow-gaging stations with 10 or more years of record
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MA BF REFERENCE CURVES Objective • Develop bankfull regional curves and equations for estimating bankfull width, mean depth, cross-sectional area, and discharge in Massachusetts
BF REFERENCE STREAMGAGES • USGS streamflow-gaging stations with 10 or more years of record • Relatively natural flow, with little to no high-flow regulation dams, diversions, etc. • Drainage areas of varying sizes • Less than 25 percent urban land use • Wadeable for surveying • Identifiable bankfull indicators
BF REFERENCE STUDY SITES OTHER STUDY
APPROACH • Rosgenstream classification method (1994) • Identify BF indicators - primarily the active floodplain, where the stream overtops its banks • BF indicator elevations were compared to the streamgagestage of the 1.05 to 2-yr recurrence interval peakflows • BF indicator, water surface, and thalwegelevations were surveyed at 20 longitudinal locations about one BF width apart to the USGS streamgage datum • At 2 (riffle section) of the 20 locations detailed cross sections were surveyed • Wolman (1954) pebble count for each stream reach
FIELD WORK • 27 USGS streamgage stream channels were surveyed • Surveyed over 6,000 elevation points • Surveyed about 36,750 ft (about 7 miles) of stream channel • Measured the median axis of 4,860 pebbles • 6 additional BF Reference Study Sites • 1 VT site – VT ANR, 2 MA sites – NRCS, and 3 sites – NY USGS • All used similar methods to this study’s work
BANKFULL ASSESSMENTS A B A B A B
MA BF REFERENCE CURVES WIDTH X-SEC DEPTH FLOW • DRAFT – SUBJECT TO REVISION • DO NOT COPY OR RELEASE
MA BANKFULLMULTIPLE REGRESSION EQUATIONS • BF Width = 10.84 (drainage area)0.39 (mean basin slope)0.19 • R2=0.91 • BF Mean Depth = 0.77 (drainage area)0.28(mean basin slope)0.13 • R2=0.85 • BF XSEC Area = 8.26 (drainage area)0.67(mean basin slope)0.32 • R2=0.95 • BF Discharge = 8.83 (drainage area)0.75 (mean basin slope)0.77 • R2=0.92 • DRAFT – SUBJECT TO REVISION • DO NOT COPY OR RELEASE
MA BF EQUATIONS - STREAMSTATS • Currently working on integrating the bankfull equations into the USGS StreamStats application http://water.usgs.gov/osw/streamstats/massachusetts.html • Streamstats is a web-site that allows the user to click any stream location and calculate selected flow and basin characteristics
OTHER AVAILABLE FG DATA • Bridge Scour database • 2,400 bridge crossing longer than 20 ft • Type, dimensions, x-sec data, bed material, etc. • NAWQA database • Some geomorphic data • Hydraulic structures and stream cross-sections surveyed for FEMA flood studies • Taunton River Basin (Spring 2010 flood) • Deerfield River Basin (T.S. Irene 2011 flood) • Hoosic River Basin (T.S. Irene 2011 flood)