What is a Watershed?

A ‘watershed,’ or ‘basin,’ is the area of land that drains to a common water body.

This map shows impaired water bodies in the Iowa River basin.

The Iowa River watershed spans just over 3 million acres (4,817 square miles) in eastern Iowa. The watershed originates in northern Hancock County, and empties into the Mississippi River in Louisa County.

This page provides links to a variety of reports and data available about the Iowa River watershed. If you are aware of an additional data source or report that you would like to see added to this page, please contact iowariverfriends@gmail.com.

Monitoring Data

IOWATER – Water Quality Monitoring Data

Iowa Flood Center – Stream Stage Sensors

USGS – Current Water Level Data. Here is a map showing all the USGS stream gages in the Iowa River Watershed with a table that describes the data each gage collects: Iowa River stream gages

National Weather Service – Advanced Hydrologic Prediction Service for the Iowa River



The goal of a TMDL, or Total Maximum Daily Load, is to determine the amount of pollutant reduction necessary in order to restore water quality in an impaired waterbody. The TMDL reports that have been developed for impaired waterways in the Iowa River watershed are provided below.

Iowa River – pathogens

Lower Pine Lake – organic enrichment

Lake Macbride – nutrients and siltation

Upper Pine Lake – siltation

Walnut Creek – Stressor Identification

Union Grove Lake – algae, pH, and turbidity