FLOOD STUDY
The Shell Creek Flood Study became an addition to the Shell Creek Watershed Study (SCWS) in 2007 as a request from the Nebraska Department of Environmental Quality (NDEQ). Their main concerns and interests were in the flow rate, fecal coliform, total solids, and nitrate level. Unlike the SCWS, we did not set dates to collect the data instead we relied on the rain activity. We tested one site on the north side of Newman Grove located on Highway 45.
To begin our data collecting we determined the width and depth of the creek. We then found the flow rate, fecal coliform count, amount of total solids present, and nitrate level. Depth and flow were measured a bit differently than how it was done in SCWS. To find the depth, we first measured from the top of the bridge to the bottom of the creek at 10 foot intervals. A fishing weight attached to the end of a tape measure was used to measure this depth. We then recorded these numbers to be used for each time we did a flood study.
Flood Study 2007
During high water, we measured the distance to the top of the water at each interval. Then, we subtracted that number from the total depth at each interval. To measure the flow rate, we used the same flow meter as in SCWS. We attached the flow meter to a retractable metal pole. We then could safely lower the meter into the water from the top of the bridge and record the readings. A water sample was collected in order to test the total solids, nitrate, and fecal coliform levels.
The first flood study numbers were considerably higher than our SCWS data. The width of the creek ranged from 32.7 to 100 feet. The flow was approximately 60 times higher during high water than SCWS readings. The fecal coliform count was approximately 28 times higher. The total solids were 19 times higher than SCWS readings. During high water, the average amount of total solids moving under the bridge was 355 tons per hour. The nitrates peaked in the beginning and dramatically dropped at the end of the month.
