City of Mission Hills, Kansas
The stormwater system in Mission Hills, Kansas, consists of about 750 storm drainage structures and 11 miles of storm drainage pipe. More than 2,000 feet of those pipes are still corrugated metal, most of which is approaching or has exceeded its usable life, and more than 10,000 feet are made of PVC, much or which is undersized for the needed capacity.
In order to update the city's 1980 Stormwater Masterplan, Water Resources Solutions began by inventorying the existing enclosed stormwater pipe system structures. A Trimble GeoXH data collector was used to collect the spatially accurate information on each structure. In addition to each structure, the outfall for each system was located and its condition rated. Structure information collected included:
Using the collected information and the hydrology calculated using HEC-HMS, the capacity of each stormwater system was analyzed using the Environmental Protection Agency’s Storm Water Management Model (SWMM). These models correlate to the outfalls in order for the city to use the models in the future for pollutant tracking.
Once the capacities of the systems were analyzed, a masterplan of recommended improvements based on capacity and condition was developed. Development of alternatives that utilize best management and eco-friendly solutions were developed, in addition to traditional infrastructure improvements. The SWMM models were used to analyze the effectiveness of the alternatives on flow rate and water quality improvement.
The project resulted in a masterplan that is GIS-based, allowing the City to interactively use and update the plan.