August 13, 2020

Keeping Lakes and Streams Clean with Stormwater Facility Maintenance

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If you have ever visited a new residential subdivision or commercial development you will likely see ponds or rain gardens that capture stormwater runoff from the site. And since the stormwater collects sediment, pollutants from chemicals applied to the land, and drippings from automobiles, you may wonder where those pollutants end up after it stops raining.  

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In the land of 10,000 lakes, Minnesotans value clean lakes and streams. And to keep our waters clean, cities and watersheds have enacted stormwater ordinances and rules to protect these natural resources. Many of our stormwater rules relate to construction activities: minimizing erosion off of developing properties and requiring permanent stormwater facilities to control and improve the quality of runoff. In addition to best management practices that contain runoff and pollutants to the individual site, ponds, rain gardens, and below-ground stormwater vaults are installed to remove pollutants in stormwater. These constructed stormwater facilities are not designed to function long-term without ongoing maintenance and cleaning, however it is often the case that the facilities are constructed and then forgotten about.


Stormwater Maintenance Agreements

To keep the stormwater facilities properly operating, most cities and watersheds require the land developer or owner to formally promise ongoing inspections and maintenance. Often those promises are in the form of a Maintenance Agreement or Declaration recorded against the property. Although the Maintenance Agreement will be tailored to each individual site, the agreements typically require annual (or more often) site inspections, thresholds for cleaning or maintenance, facility photographs, and regular reporting of the inspection findings.

Westwood has provided stormwater inspection and maintenance services for scores of projects ranging from small rain gardens to large, multi-chambered stormwater piping and below-ground vaulting systems. At the outset of these services, we will utilize the Maintenance Agreement and prepare an Operations & Maintenance Manual tailored to the specific stormwater facility and then provide the regular inspections and reports to keep the facility operating properly. Our inspections typically include a site visit, a safety protocol, and methods to inspect the facility. Sometimes the inspection is a topographic survey of a stormwater pond, whereas other times we will photograph or video below-ground facilities, measure sediment depths, and record the conditions of the facility.

Based upon our findings, the removal of sediments or maintenance of the stormwater system may be recommended. Check out this recent video inspection of a below-ground vault using a Go-Pro camera to record the conditions of the facility. In most cases we stay on the ground surface rather than descend into the stormwater facilities. If necessary, we will work with confined space experts to access and secure the needed information.

Does your project require onsite ponding or a Maintenance Agreement? We can help you in your negotiations with the agency to make sure the agreement is reasonable and not overly burdensome. Our stormwater professionals can also provide the ongoing inspections to make sure your stormwater facility is meeting the standards of the agreement and protecting the receiving waterbodies for which it was designed.


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