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Sny Magill Nonpoint Source Pollution Monitoring Project

Red ball iconSny Magill Nonpoint Source Pollution Monitoring Project

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Since October 1991, a consortium of local, state, and federal agencies has been monitoring the water quality of Sny Magill and Bloody Run creeks in Clayton County, Iowa, as part of the Sny Magill Watershed Nonpoint Source Pollution Monitoring Project. The objective of this project is to monitor and assess improvements in water quality resulting from the implementation of two special water-quality projects designed to improve farm management practices in the Sny Magill watershed: the Sny Magill Hydrologic Unit Area project and the North Cedar Creek Agricultural Conservation Program-Special Water Quality Project. North Cedar Creek is a tributary to Sny Magill Creek. The Sny Magill Nonpoint Source Pollution Monitoring Project is part of the EPA's National Monitoring Program, designed to document the measureable water-quality improvements resulting from nonpoint source control. Twenty to thirty watersheds nationwide will be monitored over a 10-year period.

Water-Quality Setting
Sny Magill, North Cedar, and Bloody Run creeks are Class "B" coldwater streams managed for "put and take" trout fishing. Both Sny Magill and Bloody Run watersheds are affected by water pollutants related to agricultural landuse and management, primarily sediment, animal waste, nutrients, and pesticides. A paired watershed approach is being used whereby improved farm management practices will be implemented within the Sny Magill watershed while no changes will be implemented in the Bloody Run watershed (adjacent watershed to the north). Bloody Run watershed will serve as the control watershed. The watersheds are well suited to a paired approach; the Sny Magill watershed drains 35.6 square miles and the Bloody Run watershed drains 37.6 square miles. The groundwater hydrogeology and known surface water characteristics are similar; both receive groundwater baseflow from the Ordovician Galena aquifer. The watersheds share surface water and groundwater divides and their proximity to one another minimizes rainfall variation. Subbasins within Sny Magill watershed will also be compared, using the paired watershed approach as well as an upstream/downstream comparison.

The Sny Magill and Bloody Run watersheds are dominantly agricultural, with no industry and little, if any, urban areas. There are no significant point sources of pollution in the watersheds. Landuse consists primarily of cropland, pasture, and forest. Half of the cropland is typically in corn, with the rest primarily in oats and alfalfa in rotation with corn.

Monitoring Design of the Sny Magill Nonpoint Source Pollution Monitoring Project
A paired watershed study comparing Sny Magill Creek watershed to the (control) Bloody Run Creek watershed (adjacent to the north) is planned. There are five monitoring components to the project: (1) U.S. Geological Survey stream gages to measure daily discharge and suspended sediment are located near the mouth of both Sny Magill and Bloody Run creeks, (2) annual habitat assessments along stretches of both stream corridors are conducted, (3) biomonitoring of benthic macroinvertebrates on a bi-monthly basis (April-October), (4) annual fisheries surveys, and (5) weekly to monthly monitoring of nine sites on Sny Magill and Bloody Run creeks for chemical and physical water quality variables.

Sny Magill Hydrologic Unit Area and North Cedar Creek Water Quality Project
The purpose of the two projects is to provide technical and cost-sharing assistance and education programs to assist farmers in the watershed in implementing farm management practices that will result in improved water quality in Sny Magill Creek. A long-term goal of a 50% reduction in sediment delivery to Sny Magill Creek has been established, as has a goal of 25% reduction in fertilizer and pesticide inputs.

The Sny Magill Nonpoint Source Pollution Monitoring Project is supported, in part, through a grant from the U.S. Environmental Protection Agency, Region VII, Nonpoint Source Program.


For more information contact Lynette Seigley (Lynette.Seigley@dnr.iowa.gov) at (319)335-1575.


Sny Magill Watershed Project: Clayton County, Iowa

Sny Magill Watershed Nonpoint Source Pollution Monitoring Project Workplan: GSB Open File Report 92-1 (Abstract)

Sny Magill Nonpoint Source Pollution Monitoring Project, Clayton County, Iowa: Water Years 1992 and 1993: GSB Technical Information Series 31 (Abstract)

Sny Magill Watershed Monitoring Project: Baseline Data: GSB Technical Information Series 32 (Preface and Table of Contents)