Stormwater: Problem or Asset?

Stormwater: Problem or Asset?. . , Urban development has greatly increased stormwater runoff in our communities. Although ancient civilizations understood the need for sewer systems to collect and carry rainwater, 19th and early 20th century city planning was often unconcerned with stormwater effects. Stormwater runoff flows directly into wetlands, lakes and rivers. Along the way it picks up trash, waste, nutrients and chemicals, causing algae blooms and pollution., In 1969 the Cuyahoga River in northeastern Ohio actually caught fire due to water pollution. This sparked nationwide calls for regulation culminating in the 1972 passage of the Clean Water Act and comprehensive efforts to study, understand and manage stormwater., Since these early efforts there have been major shifts in how we think about stormwater. Instead of concentrating on directing stormwater off site simply to reduce flooding concerns, practices now focus on retaining rain where it falls, minimizing runoff and increasing infiltration and groundwater recharge., The Cuyahoga River fire of 1969., Rethinking Stormwater , Maplewood's early roads usually had ditches. As the city matured, curbs, gutters and storm sewers became a part of the urban landscape, quickly moving water away from neighborhoods. Today stormwater is treated as an asset instead of a problem. In 1997 Maplewood's first rain garden was built just a few blocks east of here on Birmingham Street., A rain garden in your yard can capture stormwater runoff from the roof and drive. Some home rain gardens in Maplewood also capture boulevard runoff., The Birmingham Street rain garden was the first rain garden installed in Maplewood, Interested in doing this on a smaller scale? Rain gardens, shallow depressions typically planted with native flowers and grasses, are a popular way to filter rainwater runoff from roofs, sidewalks and driveways., How Does this Stormwater System Work? , Most stormwater in this neighborhood historically flowed directly into Lake Phalen with no treatment. In 2012 Maplewood constructed infiltration basins at Gladstone Savanna to capture and treat a 1.5-inch rainfall event. This is a two-cell system. Runoff from the neighborhood is piped into the northern cell where sediments settle out and small rain events infiltrate. When water levels rise during heavy rain events, water flows beneath this trail and runs down a dry creek bed, spreading out into the southern infiltration basin. Here stormwater seeps into the soil, microbes break down the pollutants, and groundwater aquifers are recharged., Numbers etched in the stormwater wall mark elevations for a 2-year, 10-year, and 100-year storm event. However, with new rainfall calculations due to climate change these numbers are now too low., This map shows the drainage area piped to the Gladstone Savanna rain basins for infiltration. In heavy rains excess water bypasses the Savanna and is piped west to Lake Phalen.