Optimizing collection system operations and improvements through a web-based flow monitoring and hydraulic modeling system for Erie County Sewer District No. 6, Buffalo, New York

Like many municipal wastewater utilities, the Erie County Department of Environment and Planning/Division of Sewerage Management (DSM) in Western New York is continually seeking methods to maximize treatment of its sewerage flows, minimize overflows and prioritize collection system maintenance and capital improvements. The DSM initiated development of the Real-Time Flow Monitoring System and Hydraulic Model in 2006 to improve the way these goals are achieved. This web-based system (completed by February 2007) was developed for Erie County Sewer District No. 6, which contains over 75 miles of sewer and serves approximately 18,000 customers. This innovative tool allows County staff to obtain up-to-the-minute status of flow and operation anywhere within the District 6 collection system, and to model “what if” scenarios regarding new flows and capital improvements.

Three technologies important to collection system decision-making were seamlessly integrated to develop this innovative web-based tool: remote wireless flow monitoring, geographic information systems (GIS) and computerized hydraulic modeling. Existing District flow monitoring stations and supplemental manhole-based flow meters and rain gauges are used to collect and transmit real-time data to the web site at 15-minute intervals. The existing County GIS database was used as the basis for system mapping and hydraulic model development.

The online model is driven by the latest hydraulics engine (USEPA’s SWMM 5) and a storm/sanitary system modeling-specific graphical decision support system (PCSWMM). A browser-based GIS interface enables visual access for users to review data, run models, and view model results. A significant feature of the system is that the user can run a hydraulic model of the past 48 hours based on real-time flow monitoring and precipitation data. Other functions allow the user to run models based on historical data or to simulate storm events. The GIS-based interface allows the user to quickly focus on areas of significance and evaluate using time scale graphing and animated hydraulic profiles.

This integrated system will be used as a predictive tool to rapidly evaluate operational and capital improvements. Examples of how this system will be used include:

1. Maximize conveyance to WWTP to minimize uncontrolled sewer overflows to receiving creeks.
2. Identify areas of surcharging and sewer overflows as they are happening.
3. Quickly identify areas of low velocity to assist in development of a flushing program.
4. High flow alarm conditions – A prompt is E-mailed to notify key staff of a significant wet weather event.
5. Model the impact of sewer system expansion or of a new significant user to determine if capital improvements are required. Evaluate improvements to remove a flow bottleneck.
6. Identify areas with highest amounts of rainfall-dependent infiltration/inflow (RDII) to prioritize rehabilitation work.