Friday, April 1, 2022

The Quality of the Water in Oakdale Lake

On Wednesday, Friends of Oakdale Lake presented the findings of a two-year water quality assessment project carried out by the ecological consulting firm Great Ecology. The final report can be reviewed here

Overall, the report is fairly encouraging. The following is the first paragraph of the Executive Summary:
Data collected during the Oakdale Lake Watershed Amelioration and Assessment Project indicates that Oakdale Lake is moderately eutrophic but appears to be a functioning ecosystem capable of cycling nutrients and supporting aquatic life. Water quality within the lake is impaired by nutrient loading from internal sources, such as excess aquatic vegetation growth followed by decomposition, and external sources, such as stormwater runoff. 

The Executive Summary goes on to identify phosphorus, which is contributing to the growth of unwanted vegetation, as a major problem for water quality and recommends three short-term actions, to be implemented within the next year:

  • Seasonal submerged aquatic vegetation (SAV) harvesting
  • Barley straw application
  • Air diffuser aeration
This isn't the first time barley straw has been recommended as a remedy for Oakdale's algae issues. Back in 2006, when Michael O'Hara was Commissioner of Public Works and Rainer Judd, then a Third Ward alderman, took on the challenge of improving water quality in Oakdale Lake, barley straw was used to try to control unwanted vegetation: "City pits barley straw against algae at lake." As it turned out, the barley straw wasn't successful because it was introduced into the lake too late in the season.

The report also recommends the following long-term management actions to control the nutrient load in the lake:
  • Installation of stormwater detention ponds and swales in critical intercept areas to be determined through confirmation of source water from storm drains
  • Consideration of green infrastructure approaches for new and existing residential and commercial developments with the potential for phytoremediation actions which use vegetation to remove contaminants. and wetland enhancement within Power Spring
  • Municipal street cleaning and litter control
  • Promoting water conservation measures for surrounding landowners, such as xeriscaping and natural lawn care
  • Community outreach and education program to inform landowners of the risks of over-fertilization of lawns 
Click here to review the entire report.

1 comment:

  1. The article in the Register Star on this topic is worthwhile reading, me thinks. Especially the Water Treatment Plant manager's responses to a few questions. It's too bad the reporter didn't ask Rob Perry, our DPW manager, if he and his family drink the tap water in their home. Bill Huston