Willowcrest Subdivision Drainage Improvements

CobbFendley performed preliminary engineering, including a hydraulic and hydrologic study for drainage improvements to the Willowcrest Subdivision in the City of Pearland. The purpose of this study is to review and evaluate the present-day condition of the drainage system servicing the project area to identify problems and areas of concern. CobbFendley performed thorough review of existing conditions and resources and developed hydraulic models of the three-year and 100-year condition.

There are approximately six individual storm sewer systems within the neighborhood and generally convey storm water out of the neighborhood to the bounding streets (Woody Road, Cherry Street, Mykawa Street and W Orange Street). An evaluation of the existing storm sewer system within the neighborhood showed that the majority of the storm sewer is unable to convey the 3-year event. The majority of the water lines were constructed in 1968 and are located in the road right of way. They are mostly made of asbestos concrete, and range in size from 2” to 8”. Sanitary sewer system within the study area was originally constructed in 1964 and approximately half of the system was rehabilitated in 2006. All of the sanitary sewer within the study area outfalls to the southeast corner of the study area, near the intersection of Cherry Street and Mykawa Road. The sanitary sewer is generally located to the rear of each lot for areas with concrete curb and gutter streets.

Four alternatives were recommended for improvements to the study area. Each alternative includes upsizing the existing storm sewer to convey the 3-year storm event, rerouting storm sewer and utilizing the ditch that flows north along Mykawa Road. The candidate project for this need area is Alternative A. This alternative includes upsizing the storm sewer systems to convey the 3-year event, and rerouting the storm sewer along Cunningham Drive, Halbert Drive, and Francis Drive to the Cherry Street trunkline. This alternative also includes replacing damaged and outdated water and sanitary sewer lines. The proposed pavement in the study area would remain the same width as the existing pavement, keeping impervious cover the same. There may also be cover issues with the proposed system. Therefore, additional survey will be needed in order to accurately model a properly sized system.