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HomeMy WebLinkAbout7 Pipeline Replacement Richards Boulevard ..... _ Agenda Item # `7 Public Utility District Memorandum To: Board of Directors From: Ed Taylor Date: April 15, 2005 Subject: Proposed Funding Source for Richards Boulevard Pipeline Replacement 1. Why this matter is before the board: The Board requested additional information and consideration of the funding source for the pipeline replacement on Richards Boulevard. 2. History: As some Board members are aware, Dart originally planned to provide water to the Tahoe Donner subdivision by constructing an intake and treatment plant at the northeast end of Donner Lake. These facilities were actually constructed, although they were never actively used by the District. The site of the treatment plant and intake is now used by the Tahoe Donner Association as a beach club and boat launch facility. Along with the treatment plant, Dart constructed a pipeline to connect to the treatment plant to the District's Donner Trails tank which is located just east of Northwoods Boulevard and just south of Bull Pine Road. On Donner Pass Road, east of Donner Lake, this pipeline is 18-inches in diameter. The 18-inch pipe then crosses under Interstate 80 and turns into a 14-inch pipe. The 14-inch pipe turns east on Richards Boulevard and Donner Pass Road. At Northwoods Boulevard, the 14-inch pipe turns north and runs to the Donner Trails Tank. The attached figure show these facilities. The portion of the pipeline under Interstate 80 and along Richards Boulevard has been in service since its original construction in 1973. The portion along Donner Pass Road was never used by the District and was dry until the Fall of 2004, Donner Lake has an elevation of about 5940 feet and the Donner Trails tank has an overflow elevation of about 6040. Elevations along Richards Boulevard range from 5930 to 5970 feet. Consequently, the 14-inch pipe in Richards Boulevard has been operating at a pressure of about 30-50 psi for the past 32 years. No leaks had been reported along this section of pipeline. When the District took possession of the Donner Lake water system, it was anticipated that this 18-inch pipe would serve as the conduit to move water from the gateway area into the Donner Lake area. In an effort to reduce costs to the Donner Lake property owners, it was determined that consolidating the north shore of Donner Lake with the Armstrong Pressure zone would provide adequate pressure to the residents of the area. The Armstrong tank has an overflow t i t elevation of about 6334. This would result in static pressures of about 155-175 psi with an additional 25-30 psi resulting from frictional losses along Richards Boulevard. In the Fall of 2004, District crews performed a pressure test on the 18-inch pipe along Donner Pass Road to ensure that it would function properly at the anticipated pressures. The pipe passed with no problems. District crews did not pressure test the 14-inch portion of the pipe since that would have involved disrupting service to some customers. Considering that the 14- inch and 18-inch pipelines were installed at the same time by the same contractor, it was assumed that the 14-inch pipe would be able to handle the increased pressure, since the 18- inch had proven adequate through testing. District crews also installed pressure reducing valves on three services along Richards Boulevard to ensure that the residences were not overpressurized. In December of 2004, District crews completed construction of the Richards Boulevard Pump Station. Some outstanding site issues such as paving remain, but the Pump Station is operational. The pump station was then turned on to pump water to the Donner Lake area. Within minutes, a leak occurred on the 14-inch pipeline along Richards Boulevard. The leak was repaired and the pump station restarted. A second leak then appeared. This process was repeated over the course of three days and about six leaks. While repairing these leaks, it was possible to examine the condition of the pipeline and measure the wall thickness. Calculations were performed regarding the 14-inch pipe and it was finally decided that the pipe would have to be replaced. The Board was informed of this problem in January 2005. 3. New information: As noted above this 14-inch pipe had been in service for 32 years with no problems. The need to convey water to the Donner Lake area increases the pressure along Richards Boulevard by about 150 psi. The existing pipe cannot handle this increased pressure and must be replaced as a result. 4. Recommendation: Water Department staff believe that the Donner Lake Assessment District is the appropriate funding source for this work since the work would not be performed without the need to convey water to Donner Lake. The Bid Price for this work is $190,824, Attachments: Map t i DONNER TRAILS TANK SITE C 14-INCH PIPE TO BEREPLACED .. INSTALLED AND PLACED INTO' ' SERVICE}N 1973 14-INCH PIPE - INSTALLED AND PLACED INTO SERVICE IN 1973 _ RICHARDS BOULEVARD ' DART TREATMENT PUMP STATION PLANT SITE 18 INCH PIPE 184NGH PIPE INSTALLED AND PLACED IN TO INSTALLED IN 1973 SERVICE IN 1973 NEVER PLACED INTO SERVICE P lic U ll DO s ct -inch and 18-inch Pipelines Public Utility District Installed in 1973 by Dart FUNDING OPTION RICHARDS BOULEVARD PIEPLINE REPLACEMENT Project cost is $190,824 Fund it temporarily from operations To complete Donner Lake project we will need to secure bridge financing and then long-term financing The $190,824 can be included in the bridge and long-term financing This portion of the financing can be supported by Donner Lake or by the Water General Fund Annual debt service payments for $190,824 @ 6.0% for 20 years is $16,636.91 i i