The Upper Town Branch Creek Watershed
Ideas on Springfield’s Urban Flooding Issue by Kent Massie
Regarding the incidents of flooding and sewage backups that are currently burdening the old combined sewer system a reduction of this problem can be achieved by installing and managing permeable pavements, detention basins, cisterns, rain gardens and conversion of pavements to lawns. Collectively these projects can make a significant reduction of excess storm-water. Many of these practices can be done with modest costs to property owners and can be effectively accomplished as part of major city infrastructure projects. A comprehensive educational program, clearly defined guidelines for new project compliance, and modest incentives for “rain ready” improvements are all achievable goals for the Upper Town Branch Creek Watershed.
Springfield IL Watershed Map where green infrastructure could best address Springfield’s downtown flooding issue.
A comprehensive storm-water management program will alone not solve the aging sewer problems and deter their eventual replacement. But, it can assist in eventually downsizing the need for major infrastructure solutions and make the community more livable.
Upper Town Branch Creek Watershed History:
The Town Branch Creek once drained the central part of the original town of Springfield. As the community grew in population during the 1800s, this creek was placed underground in a large brick sewer. This main trunk sewer and its network of lateral branch lines now collects much of the rain-water and snow-melt from the building roofs, streets, and other pavements in the watershed of the creek. Along with this storm-water, the sewer system also collects the sewage waste from the buildings. This is called a combination sewer system. Older systems, like the Town Branch Sewer, are gradually being replaced in communities with separate sewers for storm-water use and for sanitary use.
At the point where the Town Branch Sewer passes under the railroad tracks in front of the Illinois State Capitol its collection area is almost identical to the former creek’s watershed. The area is approximately one square mile or over 640 acres in size. The upper watershed is roughly bound by Monroe Street on the north, 16th Street on the east, Laurel Street on the south and the 3rd Street railroad corridor on the west. The urban area includes the southern part of downtown, three major commercial corridors and several large institutional sites. Some residential neighborhoods remain to the south and east. It can be estimated that more than half of this geographic area is currently covered with pavements, roofs, or some impervious surfaces that do not allow water to infiltrate into the ground. Urban flooding is a problem in the watershed when there are major storm events that generate more water than can be handled by the combination sewer system. The flooding of basements, street intersections and railroad underpasses are now common occurrences that result in significant insurance costs, traffic inconveniences, and sanitation concerns. An unfortunate death can be directly related to a past flooding of the Capitol Avenue underpass.
A comprehensive watershed study and an active management program for storm-water collection are needed for the entire watershed. Again, actions are needed throughout the focus area to reduce burdening the old combined sewer system and to reduce the incidents of flooding and sewage backups.
The physical control, protection, management, and use of water resources in such a way as to maintain crop, grazing, and forest lands, vegetative cover, wildlife, and wildlife habitat for maximum sustained benefits to people, agriculture, industry, commerce, and other segments of the national economy. Water conservation measures result in a reduction in applied water due to more efficient water use such as the implementation of Best Management Practices (BMP): Urban Water Use, or Efficient Water Management Practices (EWMP): Agricultural Water Use. The extent to which these actions actually create a savings in water supply depends on how they affect new water use and depletion.
Simple ways as a community that we can conserve water on a daily basis includes collection of roof run-off water for yard and garden watering, the use of low flow shower heads and toilets, planting drought resistant vegetation and installing permeable paving systems.
More to come…