Project Summary
In 1998 CRWP began to monitor the Chippewa River. The overall goal of the CRWP was to improve the water quality and flooding problems in the Chippewa River Watershed Project while also promoting a healthy agricultural, industrial and recreation-based economy for the region.

The objective of the Monitoring is to monitor and evaluate the variability of water quality and flow volume within the basin. The monitoring and assessment are used to identify which problems are present in each subregion, prioritize them, and then appropriate suits of best management practices are developed. To help achieve this objective, sampling is done using a three-pronged approach designated as Level 1, Level 2 and Level 3. Level 1 sampling involves the collection of continuous streamflow data and intensive collection of water-quality samples during runoff events. Level 2 sampling is designed to be synoptic and consists of sampling stream segments in a downstream order over a short period of time to collect baseline data that can document changes in water quality along a stream’s course. Level 3 sites are those initiated through the Citizen Monitoring Network. These sites were mostly monitored for transparency tube readings and rainfall, but these readings are useful for isolating source areas in more detail than the widespread, costly Level 1 and Level 2 efforts.

Site Location
The Chippewa River Site #18, at Hwy 40 Bridge near Milan, MN, is located in SE¼, SE¼, Sec.16, T.119 N., R.41 W., Chippewa County. This is also a USGS stream gaging site, station 05304500. This site is located on the right bank, 20 ft. downstream from State Highway 40 bridge, 2.0 miles upstream from small tributary, and 5.5 miles east of Milan. The drainage area is 1,880 square miles or 1,203,200 acres.

2001 Monitoring Season Results
2001 was a significant year for the Chippewa River. 13.5 billion cubic feet of water passed under the bridge at Highway 40. That is a lot of water. In fact, if we look at all the water that has passed under the bridge since we started monitoring in 1998, this year accounts for about half of the water we have seen over the past 4 years. This year, 51% of the water flowed out in April alone!

The spring melt began with rain on top of a large but quickly melting snow pack in April. This led to a flood that peaked at a stage that we have seen only twice in the last 63 years of USGS monitoring at the Highway 40 bridge. 1969 had just slightly lower peak and 1997 had just slightly higher peak than 2001. The Chippewa continued to stay up late into the summer, finally reaching average levels in mid August. Two major rainstorms helped keep the river up, a 2.5 in. rain in late April and a 2 in. rain in early June.

Even with this spring’s awesome flood it could not keep water levels high throughout the year. July and August left us with less rainfall than average and this caused the water levels to drop in some areas. Some Citizen Monitors reported that while they had never seen the water as high as it was this spring neither had they seen it so low this fall!

The snow, ice and extensive open water caused by the flooding may have prevented raindrop impact from playing a major role in April on erosion and total suspended solid levels. Later, we saw less rain in May (when soils are the most exposed) than in other years and it came in small amounts. Consequently, we observed less sediment in the water than we expected.

With a lot of water we expect the pollutants to be diluted and that explains a lot of what we saw. The concentration of monitored pollutants was down for most of the nutrients that we monitor. Only Phosphorous was higher in some cases.

Even though the concentrations were lower, the amounts of pollutants that washed through the Chippewa River were much larger than past years. 2001 was the worst year for overall tons of pollutants that we have seen with the exception of Total Suspended Solids. For example, at Highway 40 we figure about 253 tons of phosphorous were washed downstream (see bar graph). That is enough phosphorous to fertilize 14,471 acres of corn (following U of M recommendations for a Bray soil test of 11-15 ppm., broadcast applied with 150 bushels/acre yield goal).

Contributions to the Phosphorous loading from the municipal sewage treatment facilities of the watershed were not significant. Of the 253 tons observed municipalities contributed about 5 tons or about 2%. More significant was the water soluble Ortho Phosphorous (ortho-P). 127 tons of it went through in 2001. That is almost three times as much as in 1999 (our previous worst record).

One theory has it that the spring melt waters absorbed the ortho-P when they flooded up on the land and then carried it out as they moved out. The data suggests something like this as ortho-P levels were highest in April and then dropped as the year wore on only sliding back up in the fall when natural releases by the environment take place.

Transparency readings at the monitoring sites along the main stem indicated that water clarity was very poor this year and that they were not hospitable to fish species. Transparency tube readings by Citizen Monitors on the upstream reaches of the Chippewa observed high levels of water clarity. This implies that there are still many stretches of the watershed that still support fish populations.

Even though this was the worst year that we have seen in the past four years there is a positive side. While water levels were more than double those we have seen in previous years, pollution levels were not. Nitrate-Nitrite and Total Phosphorous were high but not double that of other years; Total Suspended Solids were much lower than expected and Fecal coliform levels were all within the EPA guidelines for swimmable waters with the exception of Shakopee Creek.