Elevated Water Storage Tank
The City of Keokuk is located in southeast Iowa along the Mississippi River. Keokuk Municipal Water Works currently operates a water treatment plant with an average daily demand of 12 to 14 MGD. The source of the water is the Mississippi River. A large percentage of water consumption comes from industrial users. In particular, the largest industrial user uses over half the capacity of the water plant during high demand periods.
The finished water storage system included a 3 million gallon clearwell located at the water treatment plant and two water towers having a capacity of 1 million gallons each. In high demand periods, the Water Work’s staff observed the water towers draining quickly and high velocities in the City’s aging water mains. This contributed to water main breaks and stained water during high demand periods.
Additional storage near the highest water users in town would provide relief to the rest of the water system and take pressure off of the water plant staff that have little time to react to the constantly changing industrial demands. A new 4 MG water tower was recommended. The new water tower is located in close proximity to the industrial zone and adequately meets peak water demands and helps reduce flow velocities in the troublesome areas of the water distribution system.
The final elevation of the new water tower matches the elevation of the existing storage tanks, and the additional capacity allows more of the operating range of the towers to be utilized. By spreading the towers further apart and reducing line velocities, less pressure loss is seen in the outlying areas of the distribution network. The number of water main breaks and stained water events has been dramatically reduced as well. The project also involved the addition of a 24-inch water main and a high service pump to provide redundancy in the distribution system. Prior to this project, if the primary water main had to be taken out of service, the City could be without water in less than 2 hours.
The project received a $2 million grant from the U.S. Economic Development Administration in addition to a $1.5 million forgivable loan from the American Recovery and Reinvestment Act. The construction of the tower began in March 2010 and was completed in the fall of 2011.
HR Green completed an engineering report, water main design, water tower design, water main and water tower construction administration (review of pay requests, change orders, Buy American compliance) and construction observation for both the water main and the water tower.