Peters Pipeline Design/Build Project
Stockton East Water District
Kjeldsen, Sinnock & Neudeck, Inc. (KSN) teamed with Floyd Johnston Construction Company, Inc. of Clovis, California, to deliver the Peters Pipeline Design/Build Project (Project) under a design/build contract with the Stockton East Water District (SEWD). The $8 million Project transports peak flows of 100 cubic feet per second at a maximum head of 25 feet from Mosher Slough, east of the town of Peters, to the SEWD Water Treatment Plant Site in east Stockton. The water is sourced from New Hogan Reservoir and New Melones Reservoir and is eventually directed to existing and future direct recharge areas located in the Eastern San Joaquin County Groundwater Basin (Basin). The Project is located east of Stockton and follows the abandoned Southern Pacific railroad right-of-way, from SEWD’s water treatment plant, eastward to a point of connection with the Farmington Canal Pipeline on the east side of Mormon Slough. Kjeldsen, Sinnock & Neudeck, Inc. provided all civil engineering, surveying, mapping, staking, right of way engineering, permitting and utility coordination for the Peters Pipeline Design/Build Project, which was connected to the SEWD water treatment plant and was in service by end of the summer of 2006.
The Project serves two main purposes: to transport surface water to recharge the Basin to a level that would provide up to 28,500 acre-feet per year that could be withdrawn from the aquifer during a dry year, and to convey surface water for a recharge program that will repel the salinity intrusion that is encroaching in the area of the Basin beneath the City of Stockton. The Project transports an average of 7,500 acre-feet per year from the New Melones Reservoir to SEWD through six (6) miles of new 60-inch diameter raw water pipeline. The Peters Pipeline Project is the first phase of a comprehensive plan to restore the groundwater storage and quality in the Basin.
The Peters Pipeline Design/Build Project had to be designed and constructed on an accelerated schedule in order to meet grant funding deadlines. In order to meet the aggressive project schedule, SEWD selected the design/build method of delivery for the Project. KSN worked extensively with FJCC and SEWD during the course of the Project to ensure that all parties were constructively coordinating with each other in order to successfully deliver the Project without compromising the Project’s tight schedule.
As the prime civil engineer on the design/build team, KSN provided all engineering and surveying services required to successfully complete the project. KSN’s comprehensive scope of services included existing utility research and potholing, coordination with utility companies on potential conflicts of alignment and grade, establishment of project horizontal and vertical control, setting control for aerial photography base maps, design surveys and mapping, detailed alternative pipe materials analysis, system hydraulic analysis, preparation of detailed construction plans and specifications, right of way engineering, permitting, construction staking, construction inspection, construction contract administration, quality control during construction, submittal review, and preparation of record drawings. KSN coordinated closely with SEWD and FJCC throughout all phases of the Project to develop cost effective and efficient solutions that met or exceeded SEWD’s design criteria.
The surveying and mapping phase of the Project included cross-sections along the pipeline alignment, and coordination for the preparation of aerial photography base maps of the entire length of the Project corridor. Detailed infill surveys were necessary at road crossings, the bridge crossing of Mosher Slough and at the points of connection.
During the preliminary design phase of the Project, KSN worked closely with SEWD, FJCC and pipe suppliers to select ten different piping scenarios examining two alternative pipeline materials, concrete pipe and high density polyethylene pipe. KSN then performed detailed hydraulic analyses and life cycle cost estimates with various combinations of pipe diameters, pipe materials, flow rates and operating heads. Based upon these scenarios, SEWD selected low-head concrete pressure pipe as the primary pipe material to be used on the Project.
The permit acquisition phase of the Project included the preparation and processing of encroachment permit application packages with San Joaquin County Public Works Department for various road crossings, and of an encroachment permit application for the bridge crossing at Mosher Slough with the State Reclamation Board.
During the design phase of the project, KSN prepared detailed improvement plans including over 32,900 lineal feet of plan/profile pipeline design, including details of connections to existing facilities, the Mormon Slough bridge pipeline crossing, crossings at roadways, air vent structures, diversion structures and miscellaneous construction details.
The Project included a number of unique design elements requiring creative design solutions. The upstream point of connection to the existing pipeline occurs at a previously existing constant-head structure located on the east side of Mormon Slough. The pipeline crossing of Mosher Slough, at the upstream end of the project, was accomplished by designing special support cradles over an abandoned railroad bridge over the Slough, allowing for the longitudinal thermal expansion and contraction of the mortar-lined, epoxy-coated, 60-inch diameter steel pipe use for the exposed portions of piping at the bridge crossing. The restrictive work area around the bridge necessitated the use of temporary rollers on the pipe support cradles that allowed the pipe to be welded at one end of the bridge and pushed across the bridge on the roller supports. Eight pressure control structures were designed and installed at critical locations along the pipeline to insure pressures within the pipeline do not exceed the allowable pipe pressures, and inlet/outlet structures were designed and installed along the pipeline alignment to allow for irrigation and/or groundwater recharge. Stubs for future extensions were installed at the Alpine Road and the Jack Tone Road crossings, with each stub having a capacity for a future flow of 50 cubic feet per second. A turning/diversion structure near the downstream end of the pipeline allows flows in the pipeline to be directed towards the SEWD Water Treatment Plant, and includes a stub for a future pipeline with a capacity of 15 cubic feet per second that will extend further to the west along the railroad right of way. The downstream terminus of the pipeline connects to an existing 48-inch diameter concrete pipe at the SEWD water treatment plant.
During the construction phase, KSN provided horizontal and vertical control surveys and construction staking, reviewed material submittals and made recommendations to SEWD on their approvals, and coordinated the daily inspection and testing of the pipeline installation. KSN also provided periodic inspections to verify that the construction was progressing in accordance with the design intent, and responded to field changes and adjustments that arose during the course of construction.
The Peters Pipeline Project is the first phase of a comprehensive project to address the need for good quality, dry year water supply, and the critically over drafted and saline damaged condition of the Eastern San Joaquin County Groundwater Basin. The Project will transport high quality surface water from reservoirs in the Sierra Nevada foothills to groundwater recharge facilities located in eastern San Joaquin County. The recharged aquifer will increase the potential yield of the aquifer during dry years and create a hydraulic barrier of fresh water to repel the salt water intrusion that is threatening the City of Stockton’s groundwater supply.
The Peters Pipeline Design/Build Project was delivered by the design/build team of Floyd Johnston Construction Co. Inc. and Kjeldsen, Sinnock & Neudeck, Inc. on schedule and on budget, with negligible contract change orders. The total design/construction cost of the project was approximately $8,000,000.
This Project earned KSN an Engineering Excellence Merit Award in 2008 from the Consulting Engineers and Land Surveyors of California (CELSOC).