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 for 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 current finished water storage system includes 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 observes the water towers draining quickly and high velocities in the City’s aging water mains. This has contributed to water main breaks and stained water during high demand periods.
Additional storage near the highest water users in town will provide relief to the rest of the water system and take pressure off of the water plant staff that currently 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 should adequately meet peak water demands and help 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 will allow more of the operating range of the towers to be utilized. By spreading the towers further apart and reducing line velocities, less pressure loss should be seen on the outlying areas of the distribution network. The project also involves the addition of 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 4.0 MG water tower is the second largest elevated storage tank in the United States. 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 is expected to be complete 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.