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Home My WebLink About3656; Interstate 5 Water Main Crossing 16 Inch; Interstate 5 Water Main Crossing 16 Inch; 1991-07-02m FEASIBILITY STUDY FOR CARLSBAD MUNICIPAL WATER DISTRICT 16 INCH WATER MAIN CROSSING OF INTERSTATE 5 FREEWAY PREPARED BY: O'DAY CONSULTANTS 7220 AVENIDA ENCINAS CARLSBAD, CA 92009 (619) 931-7700 JULY 2, 1991 91-1016 91-10X6 6-28-91 INTRODUCTION The Carlsbad Municipal Water District's Master Plan identifies the need for constructing a 16-inch water main across Interstate 5 freeway north of the Batiquitos Lagoon. The line would connect the distribution system proposed for the Broccato land development project, CT. 89-19, on the east side of the freeway with the existing 16-inch water main in Navigator Circle on the west side of the freeway. The line in Navigator Circle was constructed as part of the improvements for the Batiquitos Lagoon Educational Park Phase 1, C.T. 85-14. This feasibility study considers three altemate alignments for the crossing on the north side of Batiquitos Lagoon and evaluates rights-of-way, environmental considerations and construction constraints. LOCATION Preliminary alignment plans A, B, and C are located north of the Batiquitos Lagoon and south of Poinsettia Lane as shown on Exhibit "A". Since the crossing must connect to Piovana Court on the east side and Navigator Circle on the west side, the three altemate alignments studied are located within a zone about three hundred feet in length along the centerline of the freeway. RIGHT-OF-WAY WEST OF INTERSTATE 5; The connection to Navigator Circle would require the construction of about 430 feet of water main in undeveloped land known as Plaiming Area " D" now owned by Kaiza Poinsettia Corporation who purchased this property from Sammis Properties. An easement for the line from Navigator Circle to the westerly R.O.W. line of Interstate 5 would have to be granted by Kaiza Poinsettia Corporation. Exhibit "A" shows the main located in a private road serving a proposed townhouse development. Preparation and processing of the new master plan and tentative map for this area is tentatively scheduled for completion within the next two years. INTERSTATE 5; The freeway right-of-way is approximately 600 feet in width at this location. Because it is federally-funded, very stringent regulations limit the crossing design and Calt:rans will adhere to these requirements without concem for the impact on construction costs. Briefly the major requirements are; a. The alignment shall be a straight line from R.O.W. line to R.O.W. line. b. The water main shall be located within a steel casing from R.O.W. line to R.O.W. line. c. No stmctures shall be located within the R.O.W. lines, including jacking and receiving pits. d. Design and constmction of the crossing shall preclude the need for water district personnel to enter the freeway right-of-way to periodically perform routine maintenance. EAST OF INTERSTATE 5! For the connection to Piovana Court, about 250 feet of main would be constmcted in open-space lots 49 or 50. An easement for the alignment could be requested from Odmark & Thelan and the Davidson Companies Partnership, the developers of Broccato, CT. 89-19, who are presently processing the development plans and map with the City of Carlsbad. The alignment here is controlled mainly by environmental considerations. ENVIRONMENTAL CONSIDERATIONS WEST OF INTERSTATE 5: There are no environmental issues identified in Planning Area "D". Kaiza Poinsettia Corporation will be revising the master plan prepared and approved for the Batiquitos Ml Lagoon Educational Park, but the land use will not change and the installation of the water main could conform to the proposed land development plan. m INTERSTATE 5: The pavement and the man-made slopes within the ^ R.O.W. lines do not present any environmental constraints. * EAST OF INTERSTATE 5; Water main location and constmction is constrained at this location by the environmentally sensitive wetlands of the Batiquitos Lagoon and by the approved design of the ^ Broccato project, i« Not only is work prohibited in the wetlands, but work within a 100- foot wide buffer zone around the wetlands is restrictive. WW The limits of the wetlands and the buffer zone are shown on Exhibit "A" . m Ml Plan "A" will allow the work, including the constmction and operation of the boring and jacking pit, to be accomplished outside the buffer zone and wetlands. CONSTRUCTION CONSTRAINTS WEST OF INTERSTATE 5: Installation of the water main within Planning Area "D" can be made by the standard open trench method. If the main is to be installed prior to the constmction of the proposed housing project, the private road design would have to be finalized to ensure that the main is installed at the proper elevations. It could be several years before this road design is completed and approved. INTERSTATE 5; Plan "A" as shown on Exhibit "A" will satisfy all Caltrans requirements except for the location of the receiving pit. This is shown on the plan at the intersection of the bored and jacked segment and the existing slope on the west side of the south-bound lanes. Trenching would be required on the slope to the westerly R.O.W. line. The bored and jacked portion would be approximately 400 feet long, which is about the maximum length for boring with reasonable accuracy expected for line and grade. However, this plan will require review by the Longitudinal Encroachment Review Committee in Sacramento before it can be approved. If Plan "A" is not approved with the receiving pit located within the R.O.W. lines, then the boring operation would have to be extended another 200 feet to meet a 75-foot deep shaft constmcted on the west side of the freeway. (See profile on Exhibit "A"). Note that Plans "B" and "C", while requiring much shorter bores, have several angle points each and the jacking pits are located within the freeway right-of-way, the wetlands, and the buffer zones. Thus, plans "B" and "C" are least likely to be approved by Caltrans and the Coastal Commission. EAST OF INTERSTATE 5! As long as the jacking and boring pit is located outside the buffer zone, there are no other major constraints identified and installation of the water main should be by the standard open trench method. An access road for future maintenance of the water line should also be located outside the buffer zone. Spoil from the boring operation must not be discarded in the wetlands and buffer zone and water from the boring operation, particularly if it contains oil, must not be allowed to flow into the lagoon. RECOMMENDATIONS 1. If the water main alignments on both sides of the freeway are satisfactory to the District, Plan "A" should be detailed and submitted to Caltrans for review and approval. A preliminary constmction cost estimate for Plan "A" is attached as Exhibit "B". 3 2. Since it is important that soils data be obtained to evaluate the degree of difficulty that may be experienced in the boring and jacking operation, the soils investigation reports prepared for the constmction of the freeway should be researched and the soils data added to the crossing plan. If these records are not available, soils borings should be made to obtain the required information. The proposed drill hole locations are shown on Exhibit "A", An encroachment permit will have to be obtained from Caltrans to do the soils investigation work. 91-1016 6-24-91 ITEM QF WORK UNIT a. NAVIGATOR CIRCLE TO 1-5 R.O.W. 16" A.CP. MAIN L.F. 1" M.A.R. EA. 2" BLOWOFF EA. EXHIBIT "B" PRELIMINARY CONSTRUCTION COST ESTIMATE PLAN A UNIT COST $ TOTAL UNITS 40.00 800.00 800.00 430 1 1 SUBTOTAL: b. 1-5 CROSSING R.O.W. TO R.O.W. c. 1-5 R.O.W. TO PIOVANA COURT 16" M.L.M.C. STL. WATER MAIN 2" B.O. MISC. GRADING RESTORE SLOPES L.F. EA. CY. L.S. 1 70.00 800.00 2.00 3/000.00 SUBTOTAL: 240 1 2,500 SUBTOTAL: TOTAL COST $17,200 800 800 $18,800 1 JACKING PIT L.S. $10,000.00 $10,000 . 1 RECEIVING PIT L.S. 5,000.00 5,000 BORE & JACK 24" L.F. 140.00 400 56,000 STL.CASING 16" M.L.M.C STL. L.F. 70.00 400 28,000 WATER MAIN <••« WATER MAIN IN 24" STL. CASING L.F. 120.00 224 26,880 Wl RESTORE SLOPE L.S. 4,000.00 4,000 $129,880 $16,800 800 5,000 3,000 $25,600 TOTAL ESTIMATED CONSTRUCTION COST: $174,280 PLUS: 10% CONTINGENCIES 17,420 CIVIL ENGINEERING & SURVEYS 13,000 LANDSCAPE ARCHITECT 2,500 SOILS BORING & REPORT 3,500 TOTAL ESTIMATED COST: $210,700