Implementing Cost Effective Green Infrastructure for CSO Control in Omaha

The City of Omaha, Nebraska is including cost effective stormwater management and green infrastructure as a component of their Combined Sewer Overflow (CSO) Long Term Control Plan (LTCP). As part of the City’s five year update to the plan, additional evaluation of green infrastructure opportunities was completed. This evaluation identified a wide range of opportunities which were then narrowed to five projects that were developed into conceptual designs. The potential end of pipe CSO reduction in proportion to the cost of these projects was significant, with an estimated reduction in CSO volume of 5% for 1% of the program budget.The study followed a three step process: first, opportunity identification was performed which looked at a broad spectrum of possible green infrastructure applications. A variety of approaches considered areas where runoff is generated and management areas where practices could be constructed. Second, opportunities were filtered based on four criteria: impact, technical and institutional feasibility, project benefits and cost-effectiveness. Finally, concept designs were developed to confirm the siting feasibility, fully scoped construction costs and anticipated CSO benefit of the projects. This three step process helped to select realistic projects for the near term, while developing a robust listing of opportunities for further exploration to meet longer term planning needs.