Monday, February 23, 2015

GLWA, Don't Ignore Subsewersheds

There’s an opportunity now with the creation of the Great Lakes Water Authority (GLWA) to re-examine how ratepayer money is spent region-wide.

A good example would be efforts to reduce combined (storm and wastewater) sewer overflows in the River Rouge watershed.

In the past, Detroit water authorities concentrated efforts to reduce such overflows by building retention/treatment basins.  They have been augmenting the basins with green infrastructure, so far mostly by planting a few trees or disconnecting a few downspouts, in lower Rouge areas not far from the mouth of the river.
But the problem also occurs much farther upstream in subsewersheds.  Think of the big, interceptor sewers leading to the Detroit wastewater treatment plant as artificial rivers.  The many, smaller municipal sewer systems that feed the interceptors are like the creeks and ditches that feed natural rivers.

Reducing runoff into streams and sewers during heavy rains should begin far out in the Rouge watershed in places like Rochester Hills, West Bloomfield and Southfield.

River Rouge Watershed

Planting shrubs and trees, creating water gardens and swales, installing cisterns, paving with water-permeable materials, disconnecting downspouts from drains and impeding construction site and agricultural soil erosion throughout the watershed will pay dividends downstream at retention basins, pumping stations and wastewater treatment plants, as well as in natural water bodies.  Lower costs in the system translate into lower sewer bills for everybody.

This would be a good time for a vigorous collaboration between the new Great Lakes Water Authority and the State of Michigan to expand watershed-wide stormwater controls like those described above.

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