The frequency of channel-forming discharges in a tributary of Upper Big Walnut Creek, Ohio

Abstract

Understanding floodplain hydrology is necessary to interpret water quality and properly identify and predict the effectiveness of conservation practices in headwater watersheds. The goal of this study was to determine the frequency and magnitude of out-of-bank and channel-forming discharges in Sugar Creek, a tributary of the Upper Big Walnut Creek, in Ohio. To address this goal, a stream geomorphology study was conducted, measured discharge data at a downstream location were used to develop a calibrated discharge versus recurrence interval relationship, and the Hydrologic Engineering Center's Hydrologic Modeling System (HEC-HMS) and River Analysis System (HEC-RAS) simulation models were used to develop out-of-bank discharge recurrence interval relationships for selected locations along Sugar Creek. Much of Sugar Creek was in dynamic equilibrium and had an extensive floodplain with entrenchment ratios ranging from 2 to 18. At the eight locations studied, two experienced bankfull or larger discharges an average of 12 times per year, with an approximate 0.2-year recurrence interval. Seventy-five percent of the locations experienced bankfull or larger discharges an average of at least 3 times per year, with an approximate 0.8-year recurrence interval. All of the locations experienced out-of-bank discharges an average of at least once per year, with the 2-year recurrence interval discharge. The annual outof-bank discharges at each location ranged from 0.4% to 13% of the average annual flow volume. Based on the results, we recommended that research be conducted in the Sugar Creek Watershed to quantify the water quality benefits of a system in dynamic equilibrium and a well-attached, active floodplain.

Evaluating Geomorphic Change in Constructed Two‐Stage Ditches

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Assessment of beyond-the-field nutrient management practices for agricultural crop systems with subsurface drainage

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