Cedar Rapids, IA
The City of Cedar Rapids needed to increase its water supply because of increasing population and expanding commercial/industrial development. An economical and environmentally sensitive pair of radial horizontal collector wells were selected for the water system expansion. Well No. 1, with a 13-foot inside diameter and 77.6 feet from the top of the caisson to the bottom of the shoe, can produce 7,600 gallons per minute (approximately 10.9 million gallons per day.) The collector is equipped with six 12-inch diameter stainless steel lateral screens totalling 968 lineal feet. Well No. 2 caisson is the same size as Well No. 1. The collector is equipped with six 8-inch diameter stainless steel lateral screens totalling 948 lineal feet. Well No. 2 has a capacity of 4,500 gallons per minute (approximately 6.5 million gallons per day.)
Horizontal wells were chosen instead of vertical wells for lower operation and maintenance costs, total capacity of two horizontal wells equals fifteen vertical, and less disruption to scenic area with only two disturbed areas. The U.S. Geologic Survey provided a corridor study to locate the aquifer and Shive-Hattery completed a hydrogeological investigation to estimate the aquifer's capacity and quality before the wells were designed. Because the well pump house is at a remote site, the equipment had to be redundant, long-life, simple and provide remote monitoring and control. The system can pump water to either of two water treatment plants. Surge protection using automatic valves was installed to accommodate the water plant which was 130 feet higher than the pump house.
A computer model of the Cedar River was developed to determine the impact of well houses in 100-, 300-, and 500-year floods for a mitigation permit from the Corps of Engineers for construction within a wetland. Shive-Hattery provided design study including hydrogeologic evaluation; design plans and specifications, cost opinions, bid phase services, and construction staking. The project also included:
- Seven vertical water supply wells
- A 600-foot river crossing
- 6,000 feet, ranging from 10 to 30 diameter, raw water collection main
- 9,000 feet of raw water transmission line
- 10,000 lineal feet of power and control cables for a well field expansion
A nine-acre wetlands was developed to mitigate the impact of this project on existing wetlands.
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