What’s with that big hole in the ground at Pioneer High School in Ann Arbor? It’s the latest construction project to improve the quality of stormwater entering Allens Creek, a tributary to the Huron River that flows mostly underground through Ann Arbor. HRWC staff got a first-hand look at the project this week (it was REALLY muddy).
The project, when complete next year, will intercept and treat water runoff from 308 acres of the Allmendinger and Dickens neighborhoods before sending it to Allens Creek. The four swirl units and two basins will treat 80% of the “first flush” of rain storms and infiltrate 20% of the treated water. The basins, measuring a combined 255,000 cubic ft, will store a little less than 6 acre-ft (imagine one acre covered with 6 feet of water). The techniques in use at this site will reduce pollutants in the water, recharge groundwater, and temper peak flows during storms — all of which is good because Allens Creek is located within the middle Huron River watershed where HRWC and partners are working to meet federal and state Water Quality Standards.
The Washtenaw County Water Resources Commissioner is the lead on the project. Environmental Manager Harry Sheehan says construction costs are $3.1 million with 40% covered by federal stimulus funds and 60% covered by a 20-year low-interest loan paid for by water rates.