Water & Wastewater Master Plan

Water & Wastewater Master Plan

Location: Raymore, Mo.

Client: Raymore, Mo.

Completion Date: 2004

The City of Raymore, located in Cass County, is a southern suburb of Kansas City, Mo. Raymore has experienced rapid development over the past decade. Forecasts indicate that its population, currently 16,600, will approach 50,000 people over a 20-year planning period. In order to accommodate the rapid development, the city recognized the need upgrade the water supply and distribution and the wastewater collection and conveyance systems.

Burns & McDonnell was retained by the city to develop master plan documents pertaining to the current and future needs of the water supply and distribution and the wastewater collection and conveyance systems. Upon completion of analysis, capital improvement programs (CIPs) were developed for each system to provide budgetary guidance over a 20-year planning period. Additionally, city ordinances and standard specifications for the water and wastewater systems were updated to reflect Environmental Protection Agency and American Public Works Association standards.

  • GIS mapping
  • Flow monitoring
  • Hydraulic modeling
  • Capital improvement program development

System asset data for both the water and wastewater systems was assembled in Geographic Information System (GIS) format from as-constructed drawings, which resulted in the conservation of data and a dynamic master plan. The wastewater system included approximately 1,800 manholes, 445,000 linear feet of gravity sewer ranging from 4 to 42 inches in diameter, and one pump station with a firm capacity of 5.25 million gallons per day (MGD), which conveyed sewage through 16,000 linear feet of 24-inch diameter force main. The water system included 90 miles of 4-, 6-, 10- and 12-inch diameter PVC, ductile iron, and cast iron water lines.

Investigation of the wastewater collection system began with monitoring flow and rainfall throughout the collection system. The data collected was used to develop dry weather hydrographs and correlate rainfall events to wet weather flows. Dry and wet weather hydrographs were then modeled through the collection system. Analysis of the model results lead to the recommendation of investigating and mitigating sources of inflow and infiltration, constructing relief sewers, and upgrading Owen Good Pump Station from 5.25 MGD to 11.3 MGD. Also, future growth projections mandated that the city budget for 6 new pump stations and 152,000 linear feet of force main and gravity interceptor sewer.

Wastewater rates and tap fees for these improvements were developed to fund the capital improvement program. Following the recommendation of wastewater improvements, treatment alternatives were analyzed. Alternatives included building a city-operated treatment plant, regionalizing with a local municipality and continuing service with the Little Blue Valley Sewer District. The city of Raymore had been conveying flows to the Little Blue Valley Sewer District for a volume-based fee. Analysis was performed on a present worth basis over a 20-year project life. Final analysis indicated that the most cost effective alternative was to continue conveying flows to the Little Blue Valley Sewer District for treatment.

The water master plan includes the city’s current and projected development and associated demand through the planning period. A GIS database was developed from as-constructed drawings. Hydrant and C-factor tests were performed while pressure recorders were placed at strategic locations throughout the city to collect for model calibration and verification data. The model includes all existing distribution system components such as high service pump stations, ground, elevated storage and future improvements. The calibrated scenario, or existing system, within the model includes 90 miles of 4-, 6-, 10- and 12-inch diameter PVC, ductile iron and CIP water lines.

The future improvements scenario within the model, through the planning period, contains an additional 70 miles of similar line sizes plus 16- and 24-inch transmission lines. Costs and schedule for these improvements during the planning period were developed and included in the city’s CIP. Water rates and tap fees were developed to fund the CIP.