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HomeMy WebLinkAboutCDP 96-10; North Batiquitos Sewage Force Main; Coastal Development Permit (CDP) (11)DANIEL BO\i.L ENGINEERING, Civil Engineering Services CARLSBAD MUNICIPAL WATER DISTRICT 5950 El Camino Real Carlsbad, CA 92008 Attention: Mr. William E. Plummer, P.E. District Engineer Carlsbad Municipal Water District North Batiquitos Sewage Force Main Replacement Project CMWD Project No. 85-401 September 12, 1996 n 1 H ® LULL—" " ' ! SEP 1 51996 In accordance with Task 1 of our Proposal dated July 24, 1996, attached is our letter report including our analysis, preliminary opinion of probable costs, and recommendations for the North Batiquitos Sewer Force Main Replacement Project. We have included the pertinent comments from our meeting with you on August 29,1996, and our subsequent telephone conversations related to Alternate 3A. We are prepared to proceed with the final design and preparation of plans and specifications upon your authorization and a contract amendment to include replacement of the 8-inch water line at the top of the slope. The request for contract amendment will be sent to you under separate cover. If you have any questions regarding the above, please do not hesitate to call. DANIEL BOYLE ENGINEERING, INC. Daniel B. Boyle, P.E. Managing Engineer DBB:DGS:kmh End. C15-102-00 LTR09-96.RPT Daniel G. Smith, P.E. Associate Engineer 3142 Vista Way. Suite 201 Oeeanside, CA 92056 (619) 433-8710 FAX (619) 433-9709 CARLSBAD MUNICIPAL WATER DISTRICT NORTH BATIQUITOS FORCE MAIN REPLACEMENT PROJECT Project No. 85-401 SECTION TABLE OF CONTENTS PAGE 1.0 INTRODUCTION 2.0 ALTERNATE ALIGNMENTS 3.0 ENVIRONMENTAL CONCERNS 4.0 PRELIMINARY OPINION OF PROBABLE COST 5.0 RECOMMENDATIONS AND CONCLUSIONS INCLUDED AFTER SECTION 5.0 Exhibit No. 1 Exhibit No. 2 Exhibit No. 3 Exhibit No. 4 Exhibit No. 5 Exhibit No. 6 Exhibit No. 7 Exhibit No. 8 Alternative Route No. 1 Alternative Route No. 2 Alternative Route No. 3 Alternative Route No. 4 Section A-A Section B-B Section C-C Section D-D Table No. 1 Preliminary Opinion of Probable Construction Costs Table No. 2 Summary of Opinion of Probable Construction Costs C15-102-00 1.0 INTRODUCTION In accordance with the Scope of Work presented in our proposal dated July 24, 1996, Daniel Boyle Engineering, Inc. has completed Tasks Nos. 1.1 through 1.3, which are as follows: SCOPE OF WORK TASK NO. 1: DESIGN LETTER REPORT 1.1 Refinement of our preliminary design analysis for the three alternative force main routes, pipe alternatives, update cost estimates and prepare a list of pros and cons for each alternative. 1.2 Meet with District staff to discuss in detail our analysis and request that the District make a selection of the preferred alternative. 1.3 After the District selects the preferred alternative, summarize the results of our study in a Design Letter Report which will contain our conclusions and recommendations, submit the report to the District for approval, and request a Notice To Proceed with the final design and preparation of plans and specifications. This report represents the conclusions of our analysis of the alternative force main routes and our meeting with District staff to make a selection of the preferred alternative. 2.0 ALTERNATIVE ALIGNMENTS Four basic alternative alignments for the force main routing were identified and analyzed. The alternative alignments are shown on Exhibit Nos. 1, 2, 3, and 4, which are contained herein. 2.1 Alternative Route No. 1, refer to Exhibit No. 1, is an alignment that roughly parallels the existing force main alignment. The sections A, B, and C as shown on Exhibit Nos. 5, 6, and 7 show the existing and proposed utilities within Gabbiano Lane. The advantages and disadvantages of Alternative Route No. 1 are shown below: Advantages for Alternate No. 1 • Would allow short-term "fix" to avoid conflict with storm drain construction for Tract 89-19 within Gabbiano Lane. • Parallel route to existing force main will allow use of clearances designed in proposed tract utilities. • No additional easements required. • Allows for passage under existing 72-inch storm drain without dip section. C15-102-00 1 CMWD - North Batiqurtos Force Main Replacement Project September 1996 Disadvantages for Alternate No. 1 • Long, deep sections with greater than 7-foot of cover. • Force main still within backyard/sideyard easements. • Close proximity of existing force main in 100-foot section north of Piovana Court. 2.2 Alternative Route No. 2 which is shown on Exhibit No. 2 also roughly parallels the existing force main alignment until it intersects with Piovana Court. From that point, the alignment turns westerly and into the cul-de-sac on Piovana Court west of Gabbiano Lane. There are two variations, Alternate 2A and 2B, which depict two different force main alignments from the cul-de-sac to the point of connection with the existing manhole. The advantages and disadvantages of Alternate No. 2A and 2B are described as follows: Advantages for Alternate No. 2A • Eliminate force main in backyard easements. • Parallel route to existing force main in Gabbiano Lane will allow use of clearances designed in proposed tract utilities. • No additional easements required. • Shortest alternate route in roadways. Disadvantages for Alternate No. 2A • Dip section required to pass beneath existing 72" storm drain. • Deep sections, greater than 7-foot of cover, in Gabbiano Lane. • Potential future maintenance difficulties in sideyard easement. • Realign proposed water line in sideyard easement. • Would not provide short-term "fix" for storm drain within Tract 89-19. C15-102-00 CMWD - North Batiquitos Force Main Replacement Project September 1996 Advantages for Alternate 2B • Eliminates backyard and side yard easements to reduce future negative maintenance accessibility situations. • Parallel route to existing force main in Gabbiano Lane will allow use of clearances designed in proposed tract utilities. Disadvantages for Alternate 2B • Longest alternative route. • Requires additional easement along westerly boundary of Tract 89-19. • Dip section required to pass beneath existing 72-inch storm drain. • Deep sections (greater than 7-foot cover) in Gabbiano Lane. • Require additional environmental clearance. • Would not provide short-term "fix" for conflict with storm drain within Tract 89-19. 2.3 Alternative Route No. 3 shown on Exhibit No. 3 parallels the existing force main along the access road to the pump station, south and east of Gabbiano Lane. From that point it generally follows the westward extension of the access road to the westerly right-of-way of the access road. It then proceeds northwesterly in a long, sweeping arc, concave northeasterly to a point on the southerly right-of- way of Piovana Court. There are two variations of alignments to the point-of- connection from this point, similar in configuration to Alternate 2A and 2B, labeled Alternate 3A and 3B. The advantages and disadvantages of Alternate 3A and 3B are listed below: Advantages for Alternate 3A • Shortest alternate route. • No additional easements required. • No dip sections would be required. C15-102-00 CMWD - North Batiquitos Force Main Replacement Project September 1996 Disadvantages for Alternate 3A • Depth of excavation through hillock containing the eucalyptus stand will be 16-18 feet deep to avoid high point in line. • Several existing eucalyptus trees would probably be lost due to excavation width. • Potential future maintenance difficulties in sideyard easement. • Realign proposed water line in sideyard easement. • Would not provide short-term "fix" for conflict with storm drain within Tract 89-19. Advantages for Alternate 3B • Eliminates backyard and side yard easements to reduce future negative maintenance accessibility situations. • Out of roadway alignment. • No dip sections would be required. Disadvantages for Alternate 3B • Longest off-road alignment. • Depth of excavation through hillock containing the eucalyptus stand will be 16-18 feet deep to avoid high point in line. • Several existing eucalyptus trees would probably be lost due to excavation width. • Additional easements would be required on south side of Piovana Court cul-de-sac and along westerly boundary of Tract 89-19. • Would not provide short-term "fix" for conflict with storm drain within Tract 89-19. 2.4 Alternative Route No. 4 which is shown on Exhibit No. 4 was briefly reviewed and determined not to be feasible due to lack of capacity in existing gravity mains. No advantages or disadvantages will be discussed for this alternate. C15-102-00 CMWD - North Batiquitos Force Main Replacement Project September 1996 3.0 ENVIRONMENTAL CONCERNS As part of Task 1.2, the various alignment alternatives were discussed with the CMWD staff on August 29,1996. That meeting was also attended by Mr. Jerry Scheid of RECON, the District's environmental consultant. Mr. Scheid stated that the environmental concerns the District may face with each alternate, with the exception of those alternates traversing previously undisturbed areas of the steep slopes west of Piovana Court, would not be of major concern to the Resource Agencies, and any mitigation measures would be minimal. The areas of undisturbed steep slopes contain costal sage and are habitat to the gnatcatcher. Construction in these areas would be of concern to the Resource Agencies. 4.0 PRELIMINARY OPINION OF PROBABLE CONSTRUCTION COST Based upon our analysis, we have prepared a Preliminary Opinion of Probable Construction Cost for each viable alternative alignment. Table No. 1, attached herewith, provides a breakdown of those costs. Table No. 2 summarizes the costs of the various alternatives. The Probable Construction Costs assume ductile iron pipe as the piping material. An overall deduct for using C-900 PVC Pipe is shown on Table No. 2. Final construction cost estimates will be prepared for the selected alternative after completion of the construction plans and specifications. 5.0 RECOMMENDATION AND CONCLUSIONS Upon the review of the analysis of alternative alignments, the District selected Alternate 3A as the preferred alignment. The final location of that alignment will be refined in the final design process with emphasis on minimizing the number of fittings required. RECON has stated the impacts of this alignment would not be of major concern to the Resource Agencies, and the final design process will also be sensitive to minimizing the environmental impacts. The District must acquire an easement from the Tract 89-19 property owner for construction as well as for operation and maintenance of the proposed sewage force main. We recommend the CMWD authorize Daniel Boyle Engineering, Inc., to proceed with final design of the North Batiquitos Force Main Replacement Project and preparation of Construction Plans and Specifications as described in Task 2 of our Proposal dated July 24, 1996. The pipeline will be designed using C-900 PVC pipe which is our recommendation for the piping material. C15-102-00 CMWD - North Batiquitos Force Main Replacement Project September 1996 Ductile iron fittings will be used with the PVC pipe and will be protected from corrosion on the outside by an exterior polythane coating and a DIPRA-approved polyethylene encasement wrapped by 10 mil PVC tape along the entire length of the polyethylene encasement. In addition, each fitting shall be completely encased in concrete. The ductile iron fittings will be polythane lined to protect from interior corrosion. C15-102-00 NORTH BATIQUTTOS SEWAGE FORCE MAIN SECTION A-A R/W 60'R/W 20'20' TO DISCHARGE MANHOLE GABBIANO LANE NORTH OF PIOVANA COURT SCALES HORIZONTAL! tMO* VERTICALi 1"»10' EXHIBIT No. 5 CARLSBAD MUNICIPAL WATER DISTRICT DANIEL BOYLB ENGINEERING, INC. SEPTEMBER 1996 NORTH BATIQUTTOS SEWAGE FORCE MAIN SECTION B-B R/W 60'R/W 20*20' GABBIANO LANE SOUTH OF PIOVANA COURT SCALES HORIZONTAL: T.10' VERTICALi 1"i10' EXHIBIT No. 6 CARLSBAD MUNICIPAL WATER DISTRICT DANIEL BOYLE ENGINEERING. INC. SEPTEMBER 1996 NORTH BATIQUTTOS SEWAGE FORCE MAIN SECTION C-C R/W R/W GABBIANO LANE SOUTH OF CIGNO COURT SCALES HORIZONTAL 1"«10' VERTICAL. 1".10' EXHIBIT No. 7 CARLSBAD MUNICIPAL WATER DISTRICT DANIEL BOYLE ENGINEERING. INC. SEPTEMBER 1996 NORTH BATIQUTTOS SEWAGE FORCE MAIN SECTION D-D R/W R/W T°D'SCHARQE MANHOLE ALTERNATIVE ROUTE NO. 2 GABBIANO LANE SOUTH OF PIOVANA COURT SCALES HORIZONTAL: 1"«10' VERTICALi 1".10' EXHIBIT No. 8 CARLSBAD MUNICIPAL WATER DISTRICT DANIEL BOYLB ENOINBBRINO. INC. SEPTEMBER 1996 TABLE NO. 1 CARLSBAD MUNICIPAL WATER DISTRICT NORTH BATIQUITOS FORCE MAIN REPLACEMENT PROJECT PRELIMINARY OPINION OF PROBABLE CONSTRUCTION COSTS A. Item No. 1. 2. 3. 4. 5. 6. 7. ALTERNATE NO. 1 Quantity Description Unit 1820 LF L.S. 6EA 3EA L.S. SEA LS. 14-inch diameter polythane lined, polyethylene encased ductile iron pipe $ Metering structure Slope anchors Inspection manholes Special construction at utility crossings Corrosion protection test stations Special construction methods for steep slope construction Cost 67 LS. 1,000 1,000 LS. 1,400 LS. Subtotal B. Item No. 1. 2. 3. 4. 5. 6. 7. Total Opinion Construction Contingencies (g of Probable Construction Cost for Alternate Route ALTERNATE NO. 2A Quantity Description Unit 1800 LF LS. 6EA SEA LS. SEA LS. 14-inch diameter polythane lined, polyethylene encased ductile iron pipe $ Metering structure Slope anchors Inspection manholes Special construction at utility crossings Corrosion protection test stations Special construction methods for steep slope construction )20% No. 1 Cost 64 LS. 1,000 1,000 LS. 1,400 LS. Amount Subtotal Construction Contingencies @ 20% Total Opinion of Probable Construction Cost for Alternate Route No. 2A $ $ $ $ 121,940 42,000 6,000 3,000 5,000 5,200 30.000 213,140 42.660 255,800 Amount 115,200 42,000 6,000 3,000 4,500 5,200 30.000 206,900 41.100 248.000 C15-102-00 TABLE NO. 1 (continued) c. Item No. 1. 2. 3. 4. 5. 6. 7. ALTERNATE Quantity 2070 LF LS. 6EA 4EA LS. SEA LS. NO. 2B Description 14-inch diameter polythane lined, polyethylene encased ductile iron pipe Metering structure Slope anchors Inspection manholes Special construction at utility crossings Corrosion protection test stations Special construction methods for steep slope construction Unit Cost $ 64 LS. 1,000 1,000 LS. 1,400 LS. Subtotal Construction Contingencies @ 20% D. Item No. 1. 2. 3. 4. 5. 6. 7. Total Opinion ALTERNATE Quantity 1770 LS. 6EA 4EA LS. 3EA LS. of Probable Construction Cost for Alternate NO. 3A Description 14-inch diameter polythane lined, polyethylene encased ductile iron pipe Metering structure Slope anchors Inspection manholes Special construction at utility crossings Corrosion protection test stations Special construction methods for steep slope construction Route No. 2B Unit Cost $ 63 LS. 1,000 1,000 LS. 1,400 LS. Amount 132,480 42,000 6,000 4,000 3,000 5,200 26.000 218,680 43.720 262.400 Amount Construction Contingencies @ 20% Total Opinion of Probable Construction Cost for Alternate Route No. 3A 63 $ LS. 1,000 1,000 LS. 1,400 LS. btotal $ >20% lo. 3A 111,510 42,000 6,000 4,000 2,000 5,200 30.000 200,710 40.140 240.850 C15-102-00 TABLE NO. 1 (continued) E. ALTERNATE 3B Item No. Quantity Description 1. 2. 3. 4. 5. 6. 7. 1980 LF LS. 6EA 4EA LS. 3EA LS. 14-inch diameter pdythane lined, polyethylene encased ductile iron pipe Metering structure Slope anchors Inspection manholes Special construction at utility crossings Corrosion protection test stations Special construction methods for steep slope construction Unit Cost Amount 63 $ LS. 1,000 1,000 LS. 1,400 124,740 42,000 6,000 4,000 1,000 5,200 LS. Subtotal Construction Contingencies @ 20% Total Opinion of Probable Construction Cost for Alternate Route No. 3B 26.000 208,940 41.760 250.700 C15-102-00 TABLE NO. 2 CARLSBAD MUNICIPAL WATER DISTRICT NORTH BATIQUITOS FORCE MAIN REPLACEMENT PROJECT SUMMARY OF OPINION OF PROBABLE CONSTRUCTION COSTS ALTERNATE PROJECTED ROUTE CONSTRUCTION COST No. 1 $ 255,000 No. 2A 248,000 No. 2B 262,400m No. 3A 240.850'21 No. 3B 250.700'1'21 No. 4 N/A(3> 111 Does not include cost of preparation of easement documents or acquisition of easement. 121 Does not include replacement of eucalyptus trees. 131 This alternative is not feasible. C-900 PVC PIPE CLASS 200 MATERIAL ALTERNATE By utilizing C-900 PVC pipe in the construction of the North Batiquitos Sewage Force Main, the project construction cost could be reduced for each alternate route by approximately $21,000. C15-102-00