City of Denison Wastewater Master Planning

Plummer was retained by the City of Denison to develop a master plan for the City’s two wastewater collection systems: The Paw Paw system and the North Texas Regional Airport (NTRA) system. Goals of the master plan included developing calibrated hydraulic models of both collection systems, projecting the City’s buildout wastewater flows, determining existing and future capacities, and recommending capital projects to address capacity limitations. 

The City installed a total of 17 flow meters in both collection systems during a monitoring period of approximately four months. Twelve meters were installed in the Paw Paw collection system and the remaining five meters were installed in the NTRA collection system. Flow data collected during this period was used to determine dry and wet weather flows at each meter location. Precipitation data collected from rain gages in the collection systems were correlated to the flow data to derive the collection systems’ response to rain events. 

Following data collection, computer hydraulic models were developed for both collection systems (using EPA SWMM) to simulate existing conditions for both dry and wet weather scenarios. The models were calibrated to the data collected during the flow monitoring period to match the models to existing conditions. Using population projections developed by the City, a future wet weather design model was developed to simulate how the collection systems would respond to a 5-year storm during future buildout conditions. Based on the model projections, Plummer recommended a total of approximately $35 million of capital projects in the collection systems needed to meet projected buildout conditions.