Des Moines River Water Quality Network:

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Overview of Project

The Des Moines River Water Quality Network (DMRWQN) is a surface water quality project sponsored by the US Army Corps of Engineers that collects water samples year-round at locations along the Des Moines and Raccoon Rivers and Saylorville and Red Rock Reservoirs. The purpose of the project is to evaluate the affects of Saylorville and Red Rock Dam on downstream river quality and to characterize upstream water quality. The project was initiated in 1967 as a preimpoundment study of the Saylorville Reservoir reach and has evolved over its 38 year history to include Red Rock Reservoir.

The Scope of Work under the current research contracts specifies that over 40 parameters are to be quantified at 7 different sites on 22 separate occasions during 1997. Some analyses are done in the field in the project's mobile laboratory and the rest are conducted by the Environmental Engineering Research Laboratory in ISU's Department of Civil and Construction Engineering. The parameters examined include dissolved oxygen, pH, alkalinity, hardness, ammonia, nitrite plus nitrate, BOD, suspended solids, chlorophyll pigments, coliform bacteria and trace metals. Additionally, pesticide residues in fish are examined each spring.

Significant findings of the study have been

• that non-point sources are the main component to contamination, especially by particulate parameters;
• that improvements to the Des Moines wastewater treatment facilities have reduced ammonia nitrogen loadings in the Des Moines River downstream;
• that there appears to be no overall trend (either decreasing or increasing) in nitrate nitrogen concentrations over the 38 year period; however, from 1967-82 an increasing trend was observed;
• that pesticide concentrations are generally low but may still be of concern;
• and that gas supersaturation-induced gas bubble trauma in fish is occurring below Red Rock Reservoir.

This extensive data record has recorded water quality through several droughts and floods, including the historic flood of 1993.

Data are available through STORET and project annual reports. Currently, there are more than 445,000 individual data records generated from this project.

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