Agenda - Council - 03/10/2015 - Laserfiche WebLink

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service laterals can also be a source of inflow. Factors that contribute to their susceptibility include; age, condition, pipe material, construction, soils, and water table elevation. In the case of infiltration, groundwater seeps into cracked or broken wastewater pipes. Infiltration is a steady contributor to the problem, causing water that should be filtering down and recharging the region's aquifers to end up in rivers and flow out of Minnesota. Inflow & Infiltration Sources LEARN MORE nt►co,noaTcn The addition of clear water into the local sewer systems creates multiple problems. First, the additional flow takes capacity that was built to accommodate new development and, in some cases, the additional flow exceeds the available sewer system capacity. When the capacity of the sewer is exceeded, the wastewater backs up into basements or spills out of a manhole causing water quality concerns. Second, the clear water that gets into the wastewater system is eventually treated and discharged into the rivers, hence lost to Minnesota. Moreover, the Council charges communities the same rate for its clear water as it does for sewage. Therefore, communities have a fiscal as well as a public policy reason for ensuring that the total system functions effectively and conforms to regulations. Minneapolis, St. Paul, and South St. Paul are communities originally constructed with combined (storm and sanitary) sewer systems. Because of this, these communities continue to face additional challenges in eliminating sources of inflow. i Inflow is the biggest problem because during major rain events events it quickly consumes pipe capacity needed for current capacity and future growth. A sump pump can add 7,200 gallons of clear water to the wastewater system in 24 hours, the equivalent of the normal daily flow from 40 homes. In more extreme rain events, inflow can cause sewer backups into homes and businesses. Policy on Inflow and Infiltration: The Council will not provide additional capacity within its interceptor system to serve excessive inflow and infiltration. The Council will establish inflow and infiltration goals for all communities discharging wastewater to the regional wastewater system. Communities that have excessive inflow and infiltration in their sanitary sewer systems will be required to eliminate the excessive inflow and infiltration within a reasonable time period. Implementation Strategies: • Maintain and rehabilitate Council interceptors to minimize inflow and infiltration. • Develop inflow and infiltration goals for all communities served by the regional wastewater system. 29