A hydrologic monitoring program for Yellow Creek watershed

Abstract

Poland Village Council, in response to several recent flooding events that caused damage to properties, formed a committee called the Storm Water Abatement Team (SWAT) to study ways to reduce the future impact of storm water runoff in the Village and along Yellow Creek. There is little information about rates of runoff and flow dynamics of Yellow Creek and its tributaries available to evaluate flood reduction projects. To monitor flow rates, five gauging stations were established and stream cross-sectional area profiles for each were determined. For a wide range of flow conditions, the velocity of flow (ft/sec) and water depth (ft) were determined and the rate of flow calculated as the product of cross-sectional area and velocity. Then functional relationships between stage and flow rate were determined by constructing rating curves for the five gauging stations. Flow rates were also calculated by applying rating curve equations to citizens' monitoring data of stage at the gauging stations. Rainfall on the watershed was monitored by installing four rain gauges around the watershed. Two gauging stations were equipped with pressure sensors for continuous dept monitoring.

For the storm event on 27-28 October 2006, a detailed analysis of rainfall and streamflow hydrographs was performed to determine runoff coefficients. The runoff coefficients values obtained for the upper watershed were in the range of 0.19 to 0.24; runoff coefficients calculated for the lower watershed were in the range of 0.45 to 0.67.

Rainfall is fairly uniform around the watershed, but can differ from the average by 20% or more at some locations. Depth of flow estimates from pressure sensors did not agree with direct observations of stage in many cases; the source of error was not determined.