Citation:

Kaufmann, Phil AND M. Weber. HOW WELL CAN YOU ESTIMATE LOW FLOW AND BANKFULL DISCHARGE FROM STREAM CHANNEL HABITAT DATA? Presented at 2013 Annual Meeting of the Society of Freshwater Science, Jacksonville, FL, May 19 - 23, 2013.

Impact/Purpose:

The presenters show that low flow and bankfull discharge can be estimated from physical habitat data collected by the EPA's National Aquatic Resource Surveys at ungauged streams and rivers. This information will facilitate national and regional assessments of hydrologic alteration, which is increasing because of land development and climate change.

Description:

Modeled estimates of stream discharge are becoming more important because of reductions in the number of gauging stations and increases in flow alteration from land development and climate change. Field measurements of channel morphology are available at thousands of streams and rivers monitored by the U.S. EPA’s National Aquatic Resource Surveys. National and regional assessments of hydrologic alteration would be possible if low and bankfull flows could be accurately estimated from these data. Agreement between measured and calculated discharge would also validate hydraulic resistance estimates that have been used to calculate relative bed stability and excess fine sediments in national assessments. We used a published hydraulic resistance formula in modeling discharge from EPA’s field measurements of low and bankfull stage channel size, slope, wood, and residual depth. Compared with actual discharges (m3/s and m3/s-sq KM) ranging over six orders of magnitude in the U.S, our predictions had a SE’s less than 0.4 order of magnitude. While not sufficiently precise for individual stream assessments, these estimates would be useful for basin, regional and national scale assessments of hydrologic alteration.

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