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Existing stream channels within the City of Mission Hills are degrading. This degradation has exposed sanitary sewer crossings, caused stagnant pools to form at different locations in the stream channels and made failing stream channel walls a common occurrence. Because of this condition of the stormwater system, the City of Mission Hills commissioned Black & Veatch to update its Stormwater Master Plan. This update consists of an assessment of channel conditions and a presentation of proposed improvements aimed to enhance channel conditions and mitigate degradation. The assessment includes stream stability, habitat and water quality indicators. The stream stability portion of the assessment consisted of a detailed inventory of channel stability indicators based on the Channel Condition Scoring Matrix (CCSM) as defined in the Kansas City Metropolitan Area Chapter of the American Public Works Association (APWA) Standard Specification and Design Criteria Section 5606 guidelines. The habitat and water quality portion of the assessment consisted of field reconnaissance, streambank and streambed characterization, erosion characterization, identification of water quality indicators, vegetation identification, site photographs, and general observations of stream habitat conditions. The assessment was based on the Stream Asset Inventory (SAI) methodology, a protocol development for the City of Lenexa's Stream Assessment and Natural Resource Inventory Project (2001), and recently revised for Johnson County, Kansas. The technological tools employed for the assessment tasks included ESRI ArcPad for spatial, real-time data collection and preliminary evaluations in the field, and ESRI ArcMap Geographic Information Systems (GIS) for coordination of all information and creation of an interactive planning tool for the City. Information includes stream condition scores, proposed improvement descriptions, and an extensive set of photographs of the streams. Other project elements included hydraulic and hydrologic modeling, stream restoration and stream design. Final deliverables to the City will include the updated Master Plan Report and corresponding GIS application tool. The approach for the stream stability and habitat assessment for this project was a more holistic technique for stormwater and watershed planning. Diverging from the traditional, hard engineering approach (e.g. concrete lined channels) employed by the City of Mission Hills and surrounding communities prior to the 1990s, the City opted for geomorphology, a naturalistic methodology with respect to flood alleviation and stream stability. Based on this approach and associated recommendations of the Master Plan update, the City will implement projects that focus on restoring its main stream, Brush Creek. Ongoing design projects such as High Drive Stormwater System Improvements and Tomahawk Road Improvements incorporate traditional engineering solutions such as channel widening and storm water pipe or bridge replacement alongside natural sustainable methods such as buffer zones, vegetated banks, and meandering stream centerlines. Strategic demonstration projects have been developed by the City to address critical areas along the main stream, namely Hiawassee Park Stream Restoration and Peatwood Park Stream Restoration. The goal of the demonstration projects is to successfully mitigate channel degradation and restore stream bank stability using the recommended non traditional approach. The projects would include regular, extended monitoring of the improvements for key stability factors such as erosion and vegetation establishment, and provide experience-based benchmarks and best practices for future restoration projects on Brush Creek in the City of Mission Hills and its surroundings communities. |
