On the Upper Iowa River, a lot of improvements have been made that rate a thumbs-up from local walleye anglers. The Iowa Department of Natural Resources has invested a lot of time and money into the river and its tributaries, and the result is one of the fastest growing walleye fisheries in the state.

Located in the state's far northeastern corner, the Upper Iowa River watershed covers a thousand square miles and includes several feeder streams, some of which are outstanding trout waters.

The river flows through Winneshiek, Howard and Allamakee counties. Open prairie land borders the upper reaches of the stream until it winds its way down through 400-foot high vertical bluffs and rocky structure.

The IDNR estimates that well over 300,000 anglers a year journey to the Upper Iowa River, and some knowledgeable sources say that this is a conservative number. The river's excellent fishing is no secret, but it continues to improve despite the pressure put on it.

Fisheries biologists are pleased to report that the smallmouth bass and trout fishing have remained excellent. The river system has been so healthy that even the stocking of thousands of walleyes hasn't hurt the already established fisheries.

"In 1999, we wanted to look at the entire Upper Iowa and its watershed to check for places where nitrogen, phosphorous, atrzine and bacteria were entering the waterway," said Bill Kalishek, an IDNR fisheries biologist with the Decorah Hatchery.

Over the last six years IDNR biologists have accumulated a lot of information on where these four fish-killing substances are finding their way into the river. A number of projects have been undertaken in conjunction with county conservation boards and the federal Natural Resource Conservation Service to fix the problem.

"The benefits are already being seen, and some won't be evident for fifteen to twenty years down the road," said Kalishek.

Each project is specifically directed at an area of the watershed where water quality surveys have shown the need.

"Too much nitrogen, phosphorous, atrzine and bacteria can have a long-term impact on fishing and water quality. Phosphorous can affect walleye reproduction, while high levels of phosphorous and nitrogen affect the entire food chain all the way up from tiny bacteria to the walleyes. Generally, the lower the nitrogen and phosphorous levels, the better the fishery."

The IDNR's responses have been as varied, creative and location-specific as biologists and engineers can make them, said Kalishek. Sediment basins are one project that's received high marks from both the IDNR and surrounding landowners. The Trout, North Bear and South Bear streams were natural sites to work at controlling runoff during storms.

The basins are small dams and pipes that back up and direct the flow of water on low-lying lands during the monsoon-like rainstorms that can dump several inches of water in the area. Normally, these gully-washers would drain into the streams within eight to ten hours and take a lot of soil along with them. But water backs up behind the sediment dams to create ponds that may then take days to drain off, leaving the soil where it belongs.