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HomeMy WebLinkAboutAGENDA REPORT 1995 0104 CC SPC ITEM 04A F LL Mil, 6O7 � r 11-1 7 / S, MEMORANDUM TO: The Honorable City Council 1111111M /(41 FROM: Kenneth C. Gilbert, Director of Public Works / DATE: January 3, 1995 (CC Meeting: 1-4-95) SUBJECT: Consider Approval of Emergency Repairs to Well #1 at Arroyo Vista Community Park Background 1. As you are aware, the City has been using Well #1 (west well) as the primary source of irrigation water at the park, since the park was constructed. 2. Subsequent to the investigation and analysis of Well #2, that well was destroyed. 3 . In addition, the City has recently completed the drilling of a new Well #3 on the property. Staff and the City's consultant are proceeding with the efforts required to complete the design for the pumping equipment for that well. This new well is anticipated to be completed and operational in approximately three months. Discussion A. Investigation Recently, problems have developed with Well #1 rendering it inoperative. At present there is no irrigation water source for Arroyo Vista Community Park. In order to restore an irrigation water source in the shortest possible timeframe, staff authorized an emergency services contract (in the amount of $1,000) with a local water well maintenance contractor. That contract provided for the "pulling" of the existing well motor and pumping equipment for the purpose of determining the source of the problem(s) and the appropriate remedial action(s) . That initial work was performed during the week ending December 30th. B. Results of Initial Investigation 1. Pump: When the pump equipment was pulled from the well, it was discovered that the bearings were worn out and the tubing and boles had sustained serious damage. The cause is presumed to be due to the age of the equipment. avpwe113 Replacement of Pump for Well #1 January 1995 Page 2 2. Well: The history of Well #1 does not indicate that there have been any problems with groundwater extraction at this well site. However, a more definitive report on the condition of this well can not be provided to the City Council without retaining an engineering consultant to perform a rather extensive analysis and testing of the well. Such a study could include the T. V. inspection of the well, a geophysical loging of the aquifer and the test pumping of the well. Further remedial efforts could include the cleaning of the casing perforations and other corrective measures. A full analytical study of the condition of the well could cost between $10,000 and $20,000. The recommendations set forth below call for the installation of a new submersible pump. Should it later be determined that there are serious problems with Well #1, the new pumping equipment could be pulled from Well #1 and re-used in a new or refurbished well. At that time the City could consider undertaking a number of possible remedial efforts to Well #1 or could consider drilling a new replacement Well #4. In any event, the installation of the proposed new pumping equipment at Well #1 is completely salvageable. Should there be a problem with Well #1 the only net cost would be the labor to remove and re-install the pump. For these reasons it is not recommended that the City expend the substantial funds necessary to perform a thorough analysis of Well #1. It is recommended instead that the City proceed with the installation of a replacement pump in the existing Well #1. C. Pump Replacement Alternatives 1. Alternate #1: One option would be to replace the existing above ground pump, shaft and tubing with new like pumping equipment. This option is estimated to cost approximately $20,000. 2. Alternate #2: A second option would be to install a new submersible pump and related equipment in the existing well, suitable to provide groundwater extraction at the rate of at least 330 gpm. The estimated additional cost to provide this equipment is approximately $12,500. The scope of work would include the installation of the following: • a 40 HP submersible pump; • four-stage pump boles; • 180' of 6" column pipe; • check valve; • wiring and air line; and, • discharge piping connection and shroud. avpwe113 ► r Replacement of Pump for Well #1 January 1995 Page 3 This approach is preferred to Alternate #1 for a number of reasons including the following: • it can be done using the existing column pipe; • it would not require the installation of a new shaft and tubing; • it is maintenance free (the well would no longer require oiling) ; • in that oiling the pump would no longer be required, this approach is more "environmentally friendly;" • it is less expensive. D. Reasons for Recommended Action It is recommended that the City Council approve the immediate repair of Well #1, in the manner described in Alternate #2 above. This course of action is recommended for the following reasons: 1. Well #3 will not be operational for at least four months. The irrigation needs of the park cannot wait that long. 2. There is no expeditious way to provide irrigation water to the park on a temporary basis, short of seeking an emergency water meter from Waterworks District #1. 3. Staff has no reason to believe that there are any serious problems with the existing Well No. 1. The problems are with the pump equipment. 4. It is not cost effective to attempt to repair the existing pump in Well #1. It must be replaced. 5. The installation of a submersible pump, in lieu of a new above-ground pump, is more cost effective. 6. If it is determined that it will be necessary to proceed in the very near future with the drilling of a new Well #4, the new submersible pump and related equipment could be relocated and re-used at this new well. 7. Replacement of the pumping equipment at Well #1 provides a cost-effective short-term solution to the problem. 8. It is the intent of staff to use the new Well #3 as the primary source of irrigation water for the park. These proposed improvement to Well #1 will enable the City to use Well #1 as a good back-up source of water for a number of years to come. With these improvements, it is estimated that the construction of replacement Well #4 could be deferred approximately ten years. avpwell3 w 1 r Replacement of Pump for Well #1 January 1995 Page 4 Recommendation Staff recommends that the City Council take the following actions; 1. Approve a project for the construction of emergency repairs to Well #1 at Arroyo Vista Community Park Well #1, as defined by Alternate #1 described in this report, for a total cost not to exceed $15,000 (including the $1,000 expended for the initial investigation) . 2. Approve the use of a portion of the reserve for future capital improvements at Arroyo Vista Community Park, for the subject project. 3. Authorize the City Manager to execute necessary contract documents for the repair work required. avpwe113