Algona Water Resource Restoration

Algona, IA | Public Works

The small City of Algona, Iowa, partnered with ISG to implement practices to address water quality concerns for the East Fork Des Moines River (EFDMR) that flows along the City’s western border that is impaired with bacteria downstream of Algona’s storm sewers. ISG applied for and received grant money from IDALS on behalf of Algona to implement three best practices at three target areas to improve water quality for the EFDMR.

The City of Algona was concerned about stormwater runoff that flowed into a nearby river and needed new stormwater management infrastructure to properly filter stormwater in an environmentally responsible manner.

The first element of the project saw the reconfiguration of an IDOT right-of-way drainage area as a grassed wetland seeded with a native prairie and pollinator mix that improved uptake of contaminants from nearby parking and roadways. In addition to infiltrating the soil, the basin has a culvert that outlets to the East Fork Des Moines River with a small berm with a spillway that allows for an average of 18 inches of water to be retained in the wetland area, preventing stormwater runoff from flowing directly into the river.

The second project was the installation of a downtown bio retention cell. The cell drains 17.7 acres, 15.1 of which are impervious. The new cell helps reduce peak flow events, temporarily storing rainfall of up to 1.25 inches. A mix of native and pollinator species were planted to help store and filter pollutants, lessening the amount of nitrogen, phosphorous and bacteria entering the river.

The final project retrofitted a rundown parking lot in downtown. The asphalt pavement in the parking lot was failing and cracking, causing not just an eye sore, but also a safety concern. In addition, the parking lot was impervious, and stormwater runoff from the was carrying sediment from the site into the storm sewer where it traveled untreated to the river. To solve this, ISG retrofitted the parking lot permeable pavers, greatly reducing the amount of impervious surface. Water collected through the pavers moves through a layer of aggregate where water is able to pond for a period of time before being released to a perforated underdrain and discharged at a reduced flow rate to the storm sewer system. In addition, a series of tree trenches were installed to further improve nutritional uptake, storage and filtering of water from the parking lot.

These practices do not just represent Algona’s commitment to bettering water quality, but also illustrate the accessibility of environmentally sustainable best practices to small communities like Algona, which holds a population of around 5,000. The revamped sites will serve as examples to other small towns and cities looking to cost-effectively provide a better quality of life for their residents.

"The City of Algona has committed to these types of projects and is trying to lead the way for our community. This project will serve as a great learning tool for the general public to see and understand the need for stormwater treatment and management."

- Curt Wiseman, City Administrator, City of Algona