While DuPage County's most important waterways are healthier than they were 12 years ago, more work is needed to improve water quality, according to a new report by a local Sierra Club group.
The River Prairie Group's report, "As the River Flows," documents the progress that's been made since volunteers started monitoring the East and West branches of the DuPage River as well as Salt Creek.
The river monitoring project has been ongoing since 2000.
"They (the waterways) are all improving," said Tom Richardson, who serves on the River Prairie Group's executive committee. "Yet there are still challenges."
Richardson said those challenges are inherent to the waterways being in an urbanized area.
According to the report, monitoring shows elevated levels of nitrate and phosphate in the three waterways, although the median levels of both nutrients have fallen significantly in Salt Creek.
River Prairie Group officials said the nutrient pollution comes mostly from fertilizer runoff -- either directly into the waterways or through wastewater that is collected and treated by wastewater facilities. While phosphates and nitrates aren't toxic, they feed algae and aquatic plants. If there's overgrowth, it could result in low levels of dissolved oxygen, which is harmful to aquatic life, according to the report.
The report also states that chloride levels in Salt Creek and both DuPage River branches are "often in violation with the national aquatic life criteria" because of the use of road salt during the winter.
River Prairie Group members presented information about the report during Tuesday's DuPage County Board meeting. Connie Schmidt, who serves on the group's executive committee, said county leaders need to be aware of the data.
"With your leadership, we can continue to improve the quality of the stream," Schmidt said.
There is proof that legislation can help improve the health of rivers. For example, ammonia levels dropped after laws were enacted to reduce emissions of that chemical from treatment plants. Schmidt said ammonia levels at all nine testing sites in DuPage are below the state's water quality standard. Local treatment plants are doing "a good job" of removing the chemical, she added.
In its report, the River Prairie Group said DuPage should consider banning the application of phosphorus-containing lawn fertilizer. The group says the county also should consider a ban on coal-tar sealants containing polycyclic aromatic hydrocarbons.
"There are substitutes that don't cause the same damage," Richardson said.
Richardson said he would like to see the forest preserve acquire more vacant land along the county's waterways. Having "vegetative buffers" along rivers, streams or creeks makes them less susceptible to pollution caused by parking lots and building.
"It would be good to see the county work on trying to have a wider corridor along the river that would protect it," Richardson said.
The group also is asking municipalities and townships to reduce their road salt usage by employing anti-icing practices and/or using calibrated salt spreaders.