Duluth's bounty of urban streams have been hard-hit by development, pollution and other human impacts, according to a report released Monday by the Minnesota Pollution Control Agency.

All 11 of the designated trout streams that were assessed recently had at least one form of "impairment," the PCA noted.

The city's network of paved roads, parking lots and roofs send water into streams that's often too dirty and too warm for trout to thrive. There's also E. coli bacteria and pollutants such as road salt. Several of the streams don't have the diversity of invertebrates and other creatures that should be seen in a healthy stream.

Keene, Sargent, Merritt, Tischer and Chester creeks all have high levels of E. coli bacteria that could be coming from wildlife, pets, failing septic systems and leaking sewer lines, said Brian Fredrickson, PCA project manager.

Miller Creek has E. coli, too, but also faces compounded problems from too much chloride, or road salt, too warm of water and a lack of invertebrates that make up the base of the food chain for trout. Kingsbury Creek also lacks invertebrates.

Both branches of Amity Creek and the Lester River have too much turbidity, or sediment, in the water.

Still, most of the 11 streams studied continue to hold populations of stocked and naturally reproducing brook trout - even Miller Creek, which winds through the Miller Hill shopping corridor - lending hope that the streams can be saved if they can be buffered from human activity on land.

Duluth has 43 named streams in all - 16 of which are designated trout streams - that drain 141 square miles, from Mission Creek in the far west to Lester River on the east. Most of the streams start in wetlands and boggy headwater areas on top of the hill before dropping some 600 feet, often carrying clay and other sediment down to either the St. Louis River estuary or Lake Superior.

The PCA reports on Duluth streams are part of the statewide effort to assess and report back on what's stressing all of Minnesota's 80 major watersheds. The reports list the type and quantity of pollutants, identify where the pollution comes from and propose ways to return water quality to an acceptable level. A similar report was released last month on some North Shore streams.

The PCA is now asking for public comments on the reports before sending them on to the Environmental Protection Agency for approval. The reports are intended to be the basis to develop projects that solve the water quality impairments, with the PCA calling in help from the Board of Water and Soil Resources, the Soil and Water Conservation District, the city of Duluth and other agencies.

In the end it's going to take action by city residents to affect any real change, Fredrickson said.

The report notes that it is especially critical to preserve all remaining wetlands and forested areas at the headwaters and along the streams to help buffer water quality. Other projects include stream bank and channel stabilization, minimizing grass lawns, minimizing impervious areas such as paved parking lots, planting trees and shrubs and establishing conservation easements.

Several projects already have occurred, such as stream channel restoration along Chester Creek and bluff stabilization along several creeks, and efforts have been underway for years to slow and filter parking lot runoff near Miller Creek.

"There's no way we're going to fix these problems without engaging pretty much everyone who lives in the watershed," Fredrickson told the News Tribune. "The actions of one landowner, good or bad, can have an impact on these streams."

Even then, larger forces also are in play. At least 10 of Duluth's trout streams are projected to have summer water temperatures that are lethal to brook trout by 2050 as the region's climate warms.

The reports can be seen at www.pca.state.mn.us/duluth-urban-area-streams-watershed. Public comments on the reports will be accepted through April 18 at Brian.Fredrickson@state.mn.us.