Stormwater Management 101
Concrete work is nearly complete and birch trees are ready to be planted…construction work on the new Minnesota Capitol Complex plaza in St. Paul, MN is going smoothly. (Check out our post back in May 2014 to see how much we have progressed over the past 6 months!)
Collaborating with the architects of BWBR, Coen+Partners created a new geometry for the public space outside the Department of Transportation Building. A native Minnesota plant palette was carefully selected to celebrate the state's four seasons. One of the most eye-catching features of the new plaza, the pyramid-shaped mound, is more than architectural land-form and in fact integrates stormwater management in an abstraction of natural systems.
What is stormwater? Why should we care about it?
Stormwater is water that originates during precipitation events and snow/ice melt. Stormwater can soak in to the soil (infiltrate), be held on the surface and evaporate, or runoff and end up in nearby streams, rivers, or other water bodies (surface water).
In natural landscapes such as prairies or forests, the soil absorbs much of the stormwater and plants help hold stormwater close to where it falls. In developed environments un-managed stormwater can create two major issues: one related to the volume and timing of runoff water (flooding) and the other related to potential contaminants that the water carries, i.e. water pollution.
Stormwater is a resource and ever-growing in importance as the world's human population demand exceeds the availability of readily available water. Techniques of stormwater harvesting with point source water management and purification can potentially make urban environments self-sustaining in terms of water.
St. Paul: history of the city sewer system…
It is the summer of 1984 and a thunderstorm has just passed over St. Paul dropping heavy rains on the City. Immediately, phones at Public Works Sewer Maintenance begin to ring. There are several hundred basements flooded with combined sewage. In the streets, children are playing in the water that has bubbled up from catch basins. Toilet paper and other debris are sad reminders that this is more than stormwater. In the Mississippi River aquatic life is choking on raw sewage and industrial waste. Within hours this mixture will be flowing past drinking water intakes of downstream communities…
Being a river town, St. Paul used to have a combined sewer systems. Back in the late 19th century and early 20th century it was standard engineering practice throughout the country to convey untreated sewage and stormwater overflow to rivers or lakes in a single pipe.
In the 1920s, the obviously polluted Mississippi demanded the attention of the city and its people—something had to be done.
In 1938, the Minneapolis-St. Paul Sanitary Sewer District was created. The very first sewage treatment facility on the entire Mississippi River went into operation.
In 1967, the Federal Water Pollution Control Agency convened a conference on the pollution of the upper Mississippi River. This was the first of many steps involving many Federal, state and local agencies and interest groups that would eventually lead to the sewer separation program in St. Paul 19 years later.
By 1985, over half of the City was served by separated sanitary and storm sewer systems.
In 1986, the Accelerated Ten-Year CSO (Combined Sewer Overflow) Control started.
On May 17, 1996, the cities of Minneapolis, Saint Paul and South St. Paul, the Metropolitan Council, the Minnesota Pollution Control Agency (MPCA), the Minnesota-Wisconsin Boundary Area Commission and others celebrated the completion of the ten-year, $332 million sewer separation program for CSO elimination.
Today, St. Paul has two completely separate sewer systems, one carrying surface water runoff and the other one carrying sanitary sewage.
Nevertheless, the work of protecting and restoring the Mississippi River goes on. And stormwater management plays a key role.
How can landscape architects integrate stormwater management into design?
Common stormwater management ideas:
Curb and gutter elimination
Rain barrels and cisterns
Where can I learn more about stormwater management?
http://www.epa.gov/greeningepa/stormwater/index.htm
http://www.stpaul.gov/index.aspx?NID=2686
http://www.minneapolismn.gov/publicworks/stormwater/