The Clean Solutions for Omaha (CSO) program encompasses approximately 43 square miles of Omaha. The primary focus of the program was developed in response to an unfunded federal mandate to improve the water quality of rivers and streams in the area. In this case, the Missouri River and the Papillion Creek lie within the program territory.
In the 1970s and 80s, the federal government established water and wastewater grant and loan programs to assist communities with the financing of capital projects. Such programs currently do not exist at this time — hence the label “unfunded mandate.”
Poor water quality generally possesses the following levels: disturbed, polluted, poisoned and toxic. The driving force behind concerns in Omaha is the discharge of raw sewage into the Missouri River and the Papillion Creek that happens approximately 52 times each year. This discharge is causing the water quality to fall below federal criteria, thus requiring action to mitigate these issues.
Step 1 (from Part I: Growing Solutions – Clean Solutions for Omaha) focused on soil – field investigations. However, Step 2 is focused on another essential element, the growth cycle of plants and animals: WATER.
Step 2: water – hydrology and hydraulic modeling
Water is important to the growth cycle. Hydrology and hydraulic modeling are essential to the development of acceptable clean solutions.
Hydrology is the scientific study of rainfall and runoff. It is widely viewed as discharge for a given rainfall event over a specific timeframe. Rainfall intensity curves are used in hydrology studies and have been updated in 1945, 1978 and 1983 to keep up with the ever changing historical rainfall records.
The photographs to the right show an area located in the 48th and Burt RNC project that experiences both surface flooding and sewer backups. This is due to the flows exceeding the capacities for specific rainfall events.
The following screen shot is a 10-year rainfall event hydraulic model (hydraulic grade line) for the existing 48th and Burt RNC system, shown in the previous photos. You will see how the grade pipes and manholes are completely shaded in with blue. That means they are flowing full, with no excess capacity. This also means that our hydraulic model closely emulates the actual conditions so that our alternative solutions will be much more accurate.
Part III: Growing Solutions – Clean Solutions for Omaha will introduce Step 3 and will focus on the development and consideration of alternative solutions including:
• Sanitary sewer
• Storm sewer
• Combined sewer
• Overland flow & streets