Omaha Basin-by-Basin CSO Study
The City of Omaha selected HDR to undertake a study of the combined sanitary and storm sewer system serving an 1800-acre basin that includes downtown Omaha. Computer models for both overland storm flow and combined sewer flow were prepared (HYDRA and HEC). Current and future population and land use projections were used to estimate sewer flows and identify system limitations.
A capital improvements program listed projects to alleviate identified problems. To supplement the CIP, problem areas—including inspection of deteriorated pipe and manholes—was undertaken to provide additional information on rehabilitation needs. Sewer maps of two different scales used by the city were utilized to provide information to construct the model and prepare a base map. Where sewer maps lacked information or contained conflicting information, "as-built" construction drawings and field verification provided additional data. A complete sewer system map and figures for CIP projects were constructed on aerial photographs of the study area.
HDR performed five studies over a seven-year period. Key elements included modeling, business planning, capacity and condition, GIS, incremental construction planning and funding mechanisms.