Minutes 07/08/1980 - Laserfiche WebLink

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-"": J _..:s.. \,,/ TUESDAY JULY 8, 1980 Current Status: This element is partially complete, having been contracted in two phases. Phase I is finished and Phase 2. the section from Covington House to the treatment plant, is now under construction and projected to be complete by December, 1980. Revised Estimated Cost: $815,000 (including both phases) Element E. - Change filter media at treatment plant and make various other plant improvements Original Purpose: To increase the filtration rate from the present designed rate of five MGD to ten MGD, by changing the filter media and making other improvements necessary to operate the filters at four gallons per square foot rather than the current two gallons per square foot. Original Estimated Cost: $1.000,000 Current Status: Design completed; bids received June 17, 1980; contract awaiting award; decision required of Council by August 1, 1980. Discussion of Current Status: This element is the most complicated and expensive one in the project. There seems to be some argument about it with the State Health Department, centering around the capacity of the plant (which can be computed accurately) versus the yield of the reservoir (which can only be estimated at best and depends largely on how much rain will eventually fall in the future). It should be recalled, however, that our consultants developed a hydrological study of the watershed prior to the initiation of the project. -- The present design capacity of the plant is five MGD. However, the State had permitted the City to "force" the plant and increase the filtration rate to six MGD. Changing the filter media will increase the filtration capacity to ten MGD; but this fact is almost accidental, because the anticipated peak demand (anticipated by the end of the seven years) is only eight MGD, and the rest of the plant only currently has an eight MGD capacity. To increase the capacity of the rest of the plant to ten MGD (and thus take full advantage of the new filter capacity) would require construction of an additional flocculation basin and sedimentation basin. This would be cost effective in view of the bids received, but would increase the already sizeable cost overrun on this element. Returning to the availability of raw water supply, the treatment plant will depend on an average of six MGD, assuming extreme drought conditions, and viewed on an annual basis. This yield is the sum of five MGD from the Beaver Creek Reservoir and one MGD from the reactivated pump station at the intersection of Beaver Creek and Hairston Branch. The important point, however, according to our consultants, is that the six MGD average daily yield mentioned will be adequate to serve the expanded treatment plant capacity of eight MGD or ten MGD, whichever.