Dissertations and Theses @ UNI

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Open Access Thesis

Keywords

Nutrient pollution of water--Iowa--Dry Run Creek (Black Hawk County); Stream measurements--Iowa--Dry Run Creek (Black Hawk County);

Abstract

Dry Run Creek, a tributary to the Cedar River in northeast Iowa, is a watershed under high pressure from the surrounding region. With its headwaters located in farm fields and urban drainage ditches, it is subject to flash flooding and erosion and is on the DNR’s list of impaired waters. Dry Run Creek is similar to other small watersheds across eastern Iowa. As tributaries to the larger rivers that eventually flow into the Mississippi River and then to the Gulf of Mexico, they are significant contributors to the nutrient loading causing the hypoxia in the Gulf. The purpose of this study is to look at methods to examine low cost, simple, and effective ways to assess nutrient loading in a small stream. Rating curves can be developed and employed with water samples to assess nutrients. A rating curve is the relationship between stage (stream depth) and discharge at that location. From May 11, 2011 to August 9, 2011 rating curves were developed for 11 sites in the Dry Run Creek watershed, comparing discharge in m3/s and gauge height in cm. Various low cost methods that could be duplicated in other small watersheds were employed to develop the rating curves. The average velocity at most sites ranges from 0.2 to 0.4 m/s with an average discharge of 0.1 m3/s (3.5 cfs). Many methods face challenges, varying from unstable stream banks causing fluctuations in sediment deposits to bent gauges caused by debris during flash flooding. In some sites depths are measured by painting gauges on existing structures. Other difficulties occur where the stream is too wide and deep during high flows. Creating gauges on existing structures eliminates some of the difficulties encountered in various methods and also eliminates changes in the shape of the streambed. Methods demonstrated in this study could be utilized by other researchers to perform additional studies on small watersheds in an effort to understand their role in the nutrients being loaded into the CedarRiver. This can potentially lead to the identification of areas that are high nutrient contributors and allow us to begin to assess ways to remediate the causes.

Year of Submission

2014

Degree Name

Master of Science

Department

Environmental Science Program

First Advisor

Mohammad Z. Iqbal

Date Original

2014

Object Description

1 PDF file (xi, 83 pages)

Language

en

File Format

application/pdf

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