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April 27, 2022

H&S Presents at the Missouri Section AWWA & MWEA Joint Annual Meeting

In March, engineers from Horner & Shifrin’s Water group attended the Missouri Section AWWA & MWEA Joint Annual Meeting, where Tim Straszacker, Water Project Manager, presented on the work H&S has been performing for PWSD No. 2 of St. Charles County, Missouri to meet growing water demands in the communities they serve.

Public Water Supply District (PWSD) No. 2 of St. Charles County has grown from a small, rural water district at its inception to the largest water district in the State of Missouri, serving a population of 100,000 people and covering more than 400 square miles.  The District contains 10 different water systems, which includes the Main Water System and nine small remote systems.  The District’s service area includes the communities of Lake St. Louis, Defiance, New Melle, Augusta, Dardenne Prairie, Dutzow, parts of O’Fallon, Weldon Springs, Foristell, Flint Hill, Innsbrook, Wright City, and unincorporated St. Charles and Warren Counties.  The District also supplies wholesale water to the Cities of Wentzville and O’Fallon.

Due to significant growth of water demands throughout the District and from the City of Wentzville, the District hired Horner & Shifrin to prepare a Water System Master Plan, to evaluate the state of the existing water system and conduct a 15-year water system study to update water demand, growth rate projections, growth areas, and to identify capital improvements to meet the future demands.  The District’s main objectives were to supply more water to the District through their own Defiance Water Treatment Plant, rather than purchasing water from the City of St. Louis, and to be able to supply the shifting water demands from the main part of the water system along Highway 40 to the north and western sections of the District.

Horner & Shifrin’s evaluation determined that the City of Wentzville makes up 30% of the water system demand and that the population of Wentzville is projected to increase by nearly 60% over the next 15 years.  The main system demand is expected to increase from 14 MGD to 18 MGD average daily demand and from 58 MGD to 73 MGD peak hour demand, with the majority of the growth in the northwestern part of the system and Wentzville, resulting in undersized distribution mains and storage to feed these areas.  In addition, the undersized transmission mains from the District’s Defiance Water Plant limits the supply of water from this plant to feed these increased demand areas, requiring the District to purchase more water from St. Louis City, which is undesirable.  A water system hydraulic model was developed and evaluated, resulting in the recommendation of a 30-inch transmission main from the Defiance Water Plant to the northwestern portions of the District to supply the increased demand in this area, utilizing the full capacity of the Defiance Water Plant and reducing the District’s reliance on purchased water from the City of St. Louis.  In addition, the transmission main will be connected to the growing western isolated water systems as backup water during high demands.

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Reliability. Horner & Shifrin.