Ramsey Resident - 2015 - May/June

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Stormwater Ponds -How to Keep them Healthy (and reduce algal blooms) We've made it through another winter and are now getting ready to jump into our spring /summer routines of lawncare and landscaping projects. Many of us will begin mowing our yards, applying fertiliz- ers, and firing up the irrigation systems over the next month or two. While these are all routine activi- ties, they can each have a significant impact on our stormwater ponds, especially when considering the cumulative effect of a number of properties engaging in similar practices. Stormwater ponds are man-made ponds /basins that are designed specifically to capture and treat stormwater runoff (excess rain or snowmelt that does not evaporate or infiltrate into the ground) before the runoff enters rivers, lakes and wetlands. The ponds can hold stormwater runoff for up to several weeks, allowing pollutants and sediment to settle to the bottom, before the water either infiltrates into the ground or is discharged to natural water bodies. As the City continues to grow, more roads, drive- ways, rooftops and other hard surfaces (collectively called impervious surfaces) are constructed replacing natural vegetation, including trees and undisturbed land. So, when it rains, rather than naturally infiltrat- ing into undisturbed land, more stormwater now falls on these impervious surfaces where it can pick up sediment and pollutants before draining into a catch basin (the metal grates along the edge of streets) and being piped to a stormwater pond. Pollutants include such things as excess fertilizers, grass clippings and leaves, and other chemicals, which can have negative impacts on a stormwater pond. Excessive nutrients (primarily nitrogen and phospho- rous), either from fertilizers and /or grass clippings and leaves, can encourage growth of algae and algal lhlnnmc ` PCP nr,- nnr nnlvnnnrrrnrrive hnr ran So, even if a property is not directly adjacent to a storm- water pond, `routine' maintenance of any property can have a direct impact on stormwater ponds. But, there are some simple actions we can all take to help reduce algae and potential odors including: • Prior to fertilizing, have your soils tested to determine what, if any, nutrients are deficient. Use phosphorous -free fertilizer (it's the law, with a few exceptions) and follow label directions for application. Sweep granules off of driveways, sidewalks, and streets back onto the yard. Re- member, what the lawn doesn't absorb will be washed into the storm sewer system and ulti- mately into stormwater ponds. • Keep grass clippings and leaves out of ponds (and roads, since they wash into catch basins and into stormwater ponds). As grass and leaves decompose, they produce phosphorous, which promotes algae growth. • If you live adjacent to a stormwater pond (or any water body for that matter), consider establish- ing a buffer of native plants along the edge (the wider the better, but any little bit helps). Buffer strips can help slow down runoff and strip excess nutrients and pollutants from the stormwater before entering the pond, and they discourage waterfowl from walking onto your lawn. • Pick up pet waste and properly dispose of it. • Adjust downspouts so they discharge into the yard rather than onto sidewalks or driveways; consider installing a rain garden `downstream' from a downspout to help promote infiltration before entering the storm sewer system. If you have questions or concerns about a stormwater pond in your neighborhood, please call 763- 433 -9820.