Prairie Village Stormwater Program Improves Three Local AreasPosted on Wednesday, March 17th, 2021 by Jason Frericks
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The City of Prairie Village, Kansas identifies and repairs maintenance-based stormwater issues as part of their annual Drainage Improvements Program. The purpose of this effort is to fix old pipes and undersized boxes, which are failing. For the 2019 program, our team worked with them to improve three sites. Each came with their own distinct set of challenges.
Partnering closely with the city, we designed solutions for 71st and Mission, 87th and Catalina, and Stateline from 71st to 75th Street. Below are descriptions, outlining each effort.
71st and Mission
At 71st and Mission, the reinforced concrete box (RCB) was having capacity issues. The site needed a larger RCB to meet stormwater demands, but there wasn’t enough depth to accommodate it. The city didn’t want to redesign the roadway, so to create the appropriate slope, we graded out some of the existing channel to make it fit. We also built up the box, adding concrete on top. Then, once installed, this was paved over with asphalt. Our unique solution provided a driveable surface, while reducing flooding.
In addition, the site had a number of utility conflicts. Water, gas, sanitary sewer, cable, and power poles were all located here. The gas line’s location posed an interesting design challenge. The new RCB couldn’t be lower than the gas pipe line, and there was a gas regulation station near the creek, which had to be avoided when graded. This was challenging to do while aligning the channel, RCB, and the wingwall extents. To meet these site constraints, we worked directly with Southern Star to determine if one of the existing pipes was abandoned. As a result, we were able to remove it during construction. We also adjusted the alignment of our RCB to place it farther away from the regulation station and graded the bank away from the wingwall there.
This area has a variety of stakeholders. Businesses, the City of Mission Hills, a local golf course, and one resident were all affected by the project. To install the RCB, we had to shut down traffic. The City of Prairie Village informed those affected about the upcoming changes, minimizing the impacts as much as possible.
87th and Catalina
A shallow stormwater system at 87th and Catalina was causing flooding in a residential area. The concrete channel located behind a resident’s property is under capacity. The excess water would then back fill into the homeowner’s pool.
We performed an analysis of the roadway to determine where improvements were needed. Here, we were constrained to a shallow downstream elevation. This meant we were missing the slope required for the stormwater to drain properly. Our team worked to develop a solution without making improvements downstream within the channel. We decided to divide the proposed storm sewer into two separate systems. One system on either side of a property meant we could use smaller pipe sizes to get the slopes we needed while also being able to pick up all the drainage from the street, removing spread issues in the area.
Stateline from 71st to 75th Street
A sinkhole was beginning to form at this site due to failing pipes. The city knew this issue needed to be addressed before it became a larger problem. We started by analyzing the area and then determined some pipes needed to be upsized. Because of the site’s location, we coordinated with both the City of Kansas City, Missouri and the City of Prairie Village. Communicating with both entities was important for this busy area. In addition to these improvements, we also added sidewalks to parts of this area, stretching the city’s budget by constructing these enhancements along with their paving program.