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HomeMy WebLinkAboutSUP 07-03; South Coast Materials Quarry; Levee Maintenance Plan; 2011-06-16LEVEE MAINTENANCE PLAN SOUTH COAST MATERIALS QUARRY (SUP 07-03, SWMP 11-03, DWG 470-5A) June 16, 2011 Wayne W. Chang, MS-^E 46548 Chang Civil Engineering ° Hydrology ° Hydraulics ° Sedimentation P.O. Box 9496 Rancho Santa Fe, CA 92067 (858) 692-0760 RECORD COPY Initial CD ID 03 DC LEVEE MAINTENANCE PLAN SOUTH COAST MATERIALS QUARRY INTRODUCTION This Levee Maintenance Plan has been prepared for the levee that is part of the post-mining reclamation for Hanson Aggregates Pacific Southwest's South Coast Materials Quarry. The project site is south of Haymar Drive and west of College Boulevard in the cities of Carlsbad and Oceanside, California (see Vicinity Map). The site historically contained a quarry and associated operations. The easterly portion of the site was reclaimed a few years ago and developed with retail uses (Quarry Creek Shopping Center). Hanson is required to reclaim the remainder of the site, which is primarily in the city of Carlsbad (100.13 acres) with a small northeastern portion (4.10 acres) in the city of Oceanside. PACIFIC OCEAN VICINITY MAP NO SCALE The reclamation consists of flood control improvements and pad grading. The grading plan for reclamation in the City of Carlsbad is Drawing No. 470-5 A, and the grading plan for reclamation in the City of Oceanside is Drawing No. Gl 1-00002. Buena Vista Creek flows in a westerly direction through the middle of the site. Reclamation will enlarge a portion of the creek channel to a 150-foot wide bottom with 2.5:1 (horizontal:vertical) side slopes. Seven riprap drop structures will be incorporated along the creek bed to reduce the channel gradient and flow velocities. The reclamation will include large mass graded pads along the north and south sides of the channel. El Salto Falls is near the easterly project boundary just upstream of the channelization reach. The main creek channel at and above El Salto Falls is higher than the mass graded pad to the north creating a levee condition. Portions of the site in both Oceanside and Carlsbad will be protected by a levee as defined by the Federal Emergency Management Agency (FEMA). Title 44, Part 65.10 of the Code of Federal Regulations (CFR) outlines FEMA's levee requirements. The requirements state that "Levee systems must be maintained in accordance with an officially adopted maintenance plan . . . ." The maintenance activities must be under jurisdiction of a public agency. The CFR states that the maintenance plan "... must document the formal procedure that ensures that the stability, height, and overall integrity of the levee and its associated structures and systems are maintained. At a minimum, maintenance plans shall specify the maintenance activities to be performed, the frequency of their performance, and the person by name or title responsible for their performance." This Levee Maintenance Plan (LMP) outlines the levee design, objectives, and construction as well as operations, inspections, maintenance, and reporting. The LMP implementation and funding will be the responsibility of the landowner or their designated representative. This LMP has been prepared for the portion of the levee within the city of Carlsbad. A similar LMP will be required for the portion in the city of Oceanside. The Carlsbad portion is shown on sheet 5 of the City of Carlsbad Grading Plan Drawing No. 470-5A, which is included in Attachment A. The levee limits in Carlsbad have been added to the grading plan in Attachment A. The top of the levee is 20-feet wide and allows for access along much of the levee. When the Quarry Creek Shopping Center was constructed, an LMP was approved by the City of Oceanside for a levee along the south side of Buena Vista Creek. The LMP is included in Attachment C for reference. The City of Oceanside assumed the jurisdictional role for the levee. LEVEE OBJECTIVES, DESIGN, AND CONSTRUCTION Objectives The primary objective of the levee is to prevent 100-year flood inundation of the reclaimed pad north of Buena Vista Creek. Under pre-reclamation conditions, a portion of the north bank of Buena Vista Creek at and near El Salto Falls cannot contain the 100-year flow. As a result, flows approaching the 100-year magnitude will overtop the bank and inundate the pad area immediately to the north, which is within the cities of Carlsbad and Oceanside. A levee is required to protect against 100-year flood inundation of the pad and any potential future development. The levee will consist of an earthen embankment lined with grouted riprap along the northerly creek bank. Design Additional objectives are described in FEMA's design criteria published in Title 44, Part 65.10 of the Code of Federal Regulations (CFR). The following outlines the CFR design criteria and how each item has been met. Freeboard - The levee has been designed to provide at least 3 feet of freeboard above the 100-year water surface elevations. An additional one-half foot is provided at the upstream end of the levee. The freeboard was based on 100-year hydraulic analyses contained in Chang Consultants' May 26, 2011, Drainage Report for South Coast Materials Quarry (SUP 07-03, SWMP 11-03, DWG 470-5A). Closures - The interior (landward) drainage will flow southerly into the creek from a storm drain outfall downstream (west) of the levee, rather than through the levee. The outfall location into the creek is not in a levee condition. Therefore, closure devices are not needed. Embankment protection - The levee embankment will be founded on bedrock. Since the embankment will be along the steep falls area, the flow velocities can be high. Grouted riprap will be constructed along the creek-side to resist the high flow velocities. A minimum 2-foot layer of soil lined with Pyramat High Performance Turf Reinforcement Mat will be placed over the grouted riprap to allow planting. While the 2-foot soil layer and mat can erode, the grouted riprap will prevent erosion from propagating further. Embankment and foundation stability - Geocon, Incorporated has prepared stability and seepage analyses (March 4, 2011, Quarry Creek, Carlsbad, California, Slope Stability Analysis for FEMA Levee, and March 23, 2011, Quarry Creek, Carlsbad, California, Additional Slope Stability Analysis for FEMA Levee) verifying that the levee meets the required factors-of-safety. Settlement - Geocon, Incorporated has analyzed settlement and determined that it will be 2 inches or less. The levee height was designed to provide the necessary freeboard under the maximum settlement condition. Interior drainage - Interior drainage will not pond against the levee. It will be conveyed westerly beyond the levee and discharge into Buena Vista Creek by a storm drain pipe. Other design criteria - the project is not subject to unique situations requiring additional engineering analyses other than the hydraulic and geotechnical analyses that have been prepared for the grading permit. Operation plans and criteria - the project does not include closures or interior drainage systems that require an operation plan nor is it subject to emergency operations, a flood warning system, backup systems, or manual operation. Surface runoff will not be conveyed through the levee. The landward drainage system is a gravity system and conveys interior runoff away from the levee into Buena Vista Creek. Maintenance plans and criteria - Since the levee will be constructed of natural materials without closure systems, interior drainage systems, mechanical devices, etc., the maintenance primarily involves routine inspections to ensure the levee stability. The Levee Maintenance Plan is described in the following section. Construction Levee construction is the responsibility of Hanson Aggregates Pacific Southwest, Inc. as part of their reclamation obligation. Hanson Aggregates retained a construction management company, J.T. Kruer & Company, to monitor and oversee the overall, including levee, construction. The engineer of work, Chang Consultants, and geotechnical consultant, Geocon, Incorporated, will perform construction observation and provide as-built plans and reports. LEVEE OPERATIONS, INSPECTIONS, MAINTENANCE, AND REPORTING Operations The levee will consist of a soil and riprap-lined embankment used to resist hydraulic forces along the north bank of Buena Vista Creek. There are no required closure or other mechanical devices, backup systems, or emergency warning systems. Therefore, the levee is a passive system and an operations plan is not needed. Inspections and Maintenance Annual visual inspections by a qualified engineer familiar with levee criteria shall be performed at the beginning of each rainy season (prior to October 1) to assess the levee condition. In addition to regular annual inspections, the levee will be inspected after any unusual occurrence, such as an earthquake or 10-year or greater storm event. The purpose of an inspection is to detect conditions that might adversely affect the levee performance. Quick response to development of potentially adverse conditions will maintain the levee in good condition and performing as designed and constructed. Since an important aspect of the inspections is assessing changes that occur over time, inspection records should be accurate and complete so that a thorough documentation of conditions observed during all inspections is available. Before making a regular inspection, the inspector shall review this plan and the previous inspection reports to be thoroughly familiar with past unusual or abnormal conditions and be aware of remedial measures taken to correct adverse conditions. Inspections shall identify conditions as follows: • Review vegetative growth on the levee. Large vegetation (trees, brush, etc.) whose root system could impact the levee stability shall be removed, e.g., large roots that could impact the grouted riprap revetment. An environmental consultant shall be contacted for permitting requirements prior to removal of habitat on the creek-side of the levee. • The creek-side of the levee will be lined with Pyramat High Performance Turf Reinforcement Mat. This mat supports vegetation while providing additional protection against high flow velocities along the levee face. The mat and underlying soil are allowed to washout during high flow events. A grouted riprap revetment buried 2 feet below the mat will prevent further erosion. If the riprap revetment is exposed, the grouted riprap shall be inspected for displacement, cracking, or other damage on the surface and repairs shall be made, as needed. If the turf reinforcement mat or underlying soil shows signs of detachment, deterioration, or erosion, recommendations shall be made for reinstalling the mat and/or soil. An environmental consultant shall be contacted for permitting requirements prior to reinstallation. • Identify settlement or movement of the levee. If settlement is observed, a geotechnical consultant shall be contacted to provide an evaluation and recommendations, as needed. In the event of uncertainty related to potential minor settlement, a field survey shall be performed and compared to the as-built drawings to verify the settlement. • Identify rills, gullying, or other erosion on the levee surface. Install additional erosion control best management practices, vegetation, or perform regrading. Erosion is often the result of concentrated surface water flow at a location. In this case, measures such as adjusting grades along the levee crest can be taken to more evenly distribute the overland flow. After surface drainage has been improved, the eroded areas, if more than 6 inches deep, shall be backfilled with compacted fill. Sloughs, slides, or subsidence are indicative of instability and will be carefully evaluated by a geotechnical consultant, who shall provide repair recommendations. • Identify seepage through the levee. If seepage is noted on the landward side of the levee, a geotechnical consultant shall be contacted to provide an evaluation and recommendations, as needed. • Identify rodent damage such as burrows or mounds. Rodents shall be controlled through poisoning or trapping by authorized personnel. • Verify proper functioning of the irrigation system on the levee. The irrigation system will be routinely maintained throughout the year by the on-site landscaping personnel. The landscaping personnel can be contacted regarding the functioning, repairs, or issues associated with the irrigation system during the past year. Reporting An inspection report shall be completed by a qualified engineer following each annual inspection and submitted to the City of Carlsbad and levee owner. Photo documentation taken from identical locations each year shall be included in the report to allow an ongoing comparison of the levee condition. The inspection form included in Attachment B of this manual shall be completed for each inspection. Plan drawings or other supplemental information showing the extent of seepage, unusual settlement, and other conditions that may be significant to the performance and safety of the levee will be prepared and filed with the inspection report, as needed. Videos may be useful to document unusual or abnormal conditions. If supplemental analyses are performed as recommended following an inspection, a follow-up report will be prepared and submitted to the City of Carlsbad and levee owner. If supplemental analyses are performed as recommended following an inspection, a follow-up report will be prepared and submitted to the City of Carlsbad and levee owner. RESPONSIBLE PARTIES Funding for construction, ongoing inspections, repairs, and reporting are the responsibility of Hanson Aggregates Pacific Southwest, Inc. The City of Carlsbad will ensure that a maintenance agreement is in place for the levee responsibilities. Maintenance obligations may be transferred to a future landowner, but the transfer must maintain all inspection, repair, reporting, and funding obligations. CERTIFICATION The levee design, objectives, construction, operations, inspections, maintenance, and reporting in this plan meet the requirements of Title 44, Part 65.10 of the Code of Federal Regulations (CFR). y ¥ '"//—r Wayne W. Chang, RCE#6548 if Date OWNER'S CERTIFICATION I certify that, as the owner's representative of the property described herein, I have read and understand the requirements of this Levee Maintenance Agreement and that I am responsible for ensuring that all maintenance measures described within_,said Levee Maintenance Plan will be properly implemented. - SEE SHEET 4 LIGHT CLASS GROUTED RIPRAP (2' THICK) ON 1/2" GRAVEL(1' THICK) FILTER BLANKET. SEE RIPRAP PAD DETAIL ON SHEET 3. Q100=1.9 CFS V100=12.8 FPS LIGHT CLASS RIPRAP (21 THICK) ON 1/2" GRAVEL (1' THICK) FILTER BLANKET 0100=33.0 CFS, V100=7.1 FPS APPROX. CENTERUNE OF 12' WIDE EASEMENT FOR POLE LINES, UNDERGROUND CONDUITS. INCIDENTAL PURPOSES, RIGHT OF INGRESS AND EGRESS TO SDG&E RLE NO. 144668 REC. 7-18-60 \, 50' PLANNING BUFFER EXTENDED DETENTION BASIN NO. 2D(TENDED DETENTION BASIN NO. 2 FOR GRADING IN THIS AREA SEE CITY OF OCEANSIDE GRADING PLAN DRAWING NO. G11-0000215" UTILITY/SLEEVE, IE=80.00/ fl I — 10" LANDSCAPE & IRRIGATION 10' WIDE LANDSCAPE MAINTENANCE EASEMENT TO ERIC SUNDT RLE NO. 87-303413 REC. 6-2-87 STORM DRAIN LJNE-4 SEE SHEET 11 FOR PROFILEPROPOSED BURIED RIPRAP (TYPICAL). SEE DETAIL C-C SHEET 2. 106.0 **^c^ [~HP SLEEVE, IEy80.QO 100' BIOLOGICAL BUFFER 78.33 FG RIGHT OF WAY FOR INSTALLATION OF IRRIGATION IMPROVEMENT, AND LANDSCAPING INCIDENTALS RLE NO. 90-086570 REC. 2-16-90 GROUT RIPRAP TO EXIST. ROCK 1/2-TON RIPRAP (3.4' THICK) ON 1" GRAVEL (11 THICK) OVER SAND (V THICK, 25% PASSING |200 SIEVE) FILTER BLANKET 1/2-TON GROUTED RIPRAP (3.4' THICK) ON 1" GRAVEL (1' THICK) OVER SAND (1' THICK, 25% PASSING J200 SIEVE) FILTER BLANKET PROPOSED BURIED RIPRAP (TYPICAL). SEE DETAIL C-C SHEET 2. 3 / N68'35'49"E 78.06' ry * ) 1 ' } 100' BIOLOGICAL BUFFER FINISH GRADE TOP OF SLOPE CREEK SLOPE LEAVE PIPE 24' MIN. ABOVE GRADE 1/2-TON RIPRAP (3.4' THICK) ON 1 GRAVEL (1' THICK) OVER SAND (V THICK, 25% PASSING $200 SIEVE) FILTER BLANKET PROPOSED RIPRAP (TYPICAL)DROP STRUCTURE IN CREEK 50 PLANNING BUFFER 15" UTILITY SLEEVE , IE=80.00 »-"" 10"/LANDSCAPE 4 IRRIGATION SLEEVE, IE=80.00 12' WIDE EASEMENT FOR POLE LINES, UNDERGROUND CONDUITS, INCIDENTAL PURPOSES, RIGHT OF INGRESS AND EGRESS TO SDG&E RLE NO. 82557 REC. 5-12-61 IRRIGATION SLEEVE PER PLAN " STORM DRAIN UNE-2 SEE SHEET 10 FOR PROFILE 48.2 LF ~ 4 PVC O 18.82%Low-aow PIPE IRRIGATION PIPE SLEEVING W/ PREINSTALLED MAINLINE AND CONTROL WIRE DETAIL 12 WIDE EASEMENT FOR POLE LINES, UNDERGROUND CONDUITS, INCIDENTAL PURPOSES, RIGHT OF INGRESS AND EGRESS TO SDG4E RLE NO. 187760 REC. 10-30-61 NOT TO SCALE TOP OF SLOPE - FMSH GRADE 12' WIDE EASEMENT FOR POLE LINES, UNDERGROUND CONDUITS, INCIDENTAL PURPOSES. RIGHT OF INGRESS AND EGRESS TO SDG&E RLE NO. 74-190297 REC. 6-16-74 DROP STRUCTUREIN CREEK BIO-RLTER SWALE 26' BOTTOM WIDTH; 3:1 SIDE SLOPES; 1' DEEP; 138' LONG MIN.15 UTILITY SLEEVE PER PLAN LIGHT CLASS GROUTED RIPRAP (2 THICK) ON 1/2" GRAVEL (V THICK) RLTER BLANKET. SEE RIPRAP PAD DETAIL ON SHEET 3. 1-* 0100=23.3 CFS V100=17.9 FPS - SEE SHEET 8 ////, ,,. ArV-_ / / /15" UTILITY SLEEVE DETAIL IRRIGATION CONTROL WRE TAPED TO PIPE - 5' LENGTH ABOVE GRADE 3' CLASS 315 PVC PIPE 2 MRE CABEL PAIGE IRRIGATION P7072D W/ RED JACKET HOJEL FOR WORK WITHIN SDG&E EASEMENTS SHOWN HEREON, SEE "LETTER OF PERMISSION FOR GRADING AND CONSTRUCTION OF GRADING IMPROVEMENTS" FROM SDG4E DATED MAY 18, 2011. LIMITS OF LEVEE (CITY OF CARLSBAD) Chang PO to 9196 RncWStnta Ft, CA 92067 CONSTRUCTION NOTES: (7) PROPOSED WILLOW TUBE LOCATION TYPICAL ALL DROP STRUCTURES. SEE WILLOW TUBE DETAIL ON SHEET 6. (2) INSTALL No. 2 BACKING RIPRAP (V THICK) OVER DG RLTER BLANKET (1' THICK) WITHIN 2' RADIUS AROUND 4" PVC INLET CONSTRUCT SLOPE ROUNDING AT ALL TOP OF SLOPE CONDITIONS PER SAN DIEGO COUNTY DESIGN STANDARD DS-10. BMP TABLE BMP TYPE BIO-RLTER SWALE EXTENDED DETENTION BASIN NO. 2 QUANTITY / SIZE 138 LINEAR FOOT BOTTOM DIMENSIONS: 11'W x 33'L x 6'D VOLUME: 2,360 CF REQ'D. I.M.P. AREA: 1,742 AREA PROVIDED: 2,807 SF SF "AS BUILT" REVIEWED BY: ENGINEER OF WORK REVISION DESCRIPTION OTHER APPROVAL art APPROVAL SHEET 5 CITY OF CARLSBAD |[»P ENGINEERING DEPARTMENT GRADING PUNS FOR SOUTH COAST MATERIALS QUARRY GRADING PLAN APPROVED: GLEN K. VAN PESKI SENIOR CM. ENGINEER PE 41204 EXPIRES 3/31/13 OWN BY: CHKD BY:RVWD BY:L PROJECT NO. SUP 07-03 DRAWING NO. 470-5A ATTACHMENT A. CITY OF CARLSBAD GRADING PLAN WITH LEVEE IDENTIFIED ATTACHMENT B INSPECTION FORM SOUTH COAST MATERIALS QUARRY LEVEE INSPECTION RECORD Inspection Date: Inspector(s) / Company / Phone: Reason for Inspection: Scheduled Following Unusual Occurrence (specify) Photographs and Photo Location Map Attached: Yes No Previous Inspection Reports and Levee Maintenance Plan Reviewed: Yes No Previously Recommended Corrective Measures Undertaken: Yes No INSPECTION ITEMS: Outboard (Buena Vista Creek-Side) Embankment Slope • Vegetation • Pyramat High Performance Turf Reinforcement Mat • Soil o Movement o Settlement o Rills, gullies, erosion o Seepage Grouted 1/2-Ton Riprap (if exposed) • Rodents (burrows, mounds) • Irrigation System Interior (Landward) Embankment Slope • Vegetation • Soil o Movement o Settlement o Rills, gullies, erosion o Seepage Rodents (burrows, mounds) Irrigation System Embankment Crest • Vegetation _ • Soil o Movement o Settlement o Rills, gullies, erosion • Rodents (burrows, mounds) • Irrigation System Additional Inspection Findings or Tasks Performed (surveying, mapping, video, etc.), if applicable RECOMMENDATIONS: Corrective Measures Additional Investigations Recommended to be Performed by Others (geotechnical consultant, environmental consultant, etc.) Other Recommendations ATTACHMENT C QUARRY CREEK SHOPPING CENTER LEVEE MAINTENANCE PLAN LEVEE MAINTENANCE PLAN Introduction NFIP regulations requite that an officially adopted levee maintenance plan be followed as detailed in paragraph 65.10(c)(3)(d). Hie following plan mirrors the regulations and discusses maintenance activities to be performed, the frequency of their performance, and the person by name or title responsible for their performance. Maintenance Activities This plan divides maintenance activities into the following functions: inspection, investigation and testing, repairing, and reporting. Inspection Inspection is the observation of the flood control system to determine if it is in a properly functioning condition. It includes locating and making recommendations for repairs to any damage, insuring mat access to the facility is maintained, and that the floodway and associated flood control system is clear of encroachments. The inspection function results in one of three general conclusions. The first is the assessment that the facility is in the as-constructed condition and therefore requires no repairs. The second is the assessment that there are deficiencies present and the repairs required to correct the problems are obvious from the inspection alone. The third is the assessment that there are deficiencies but the required repairs are not obvious from direct inspection. Investigation and testing In the situation where required repairs are not obvious the maintenance function advances to the investigation and testing level. This is a program to provide criteria for making maintenance decisions. An example is the regular deployment of a survey crew to establish the elevations of the top of the levee to evaluate if the height is adequate. Another example is the monitoring of a crack if it should show up in concrete to see if there is still movement or if the crack is stable. Evaluating the results from investigating and testing are followed by recommendations for action. Repairing Repairing is the act of following the recommendations for corrective action made during the maintenance process. Each time a program of repairs takes place the work is followed by an inspection. It is also followed by investigation and testing if appropriate. Reporting Reporting is done in written form to document each step in the maintenance process. Inspection uses a standard form similar to the U. S. Army Corps of Engineers Form SPL 403 (example at the end of this section). Investigation and testing requires more detailed reporting appropriate for the particular situation. Repairing requires industry standard documentation normal to any construction in addition to the completion of SPL 403. All reports are to be submitted to the City of Oceanside Engineering Department. Areas of Maintenance Items to be maintained within the plan include the levee, floodwall, Buena Vista Creek adjacent to Quarry Creek, the College Boulevard culverts, retaining walls, underground drainage conduits, landscape and irrigation systems. Levee Areas of maintenance for the levee include geotechnical stability, height, erosion, siitation, degradation due to root damage, subsurface drainage system, impermeable core integrity, and any other items deemed necessary to the proper functioning of the levee. Floodwall Areas of maintenance for the floodwall include the structural integrity of the wall, the wall finish, and the height. Buena Vista Creek and College Culverts Areas of maintenance for the creek include keeping the channel and culverts clear of debris, excessive wild growth, waste materials, and unauthorized building structures or other encroachments. Retaining Walls Areas of maintenance include the structural integrity of walls that retain the south side of the levee. Landscape and irrigation Systems Areas of maintenance of the landscaping include pruning, pest control, weed abatement, fertilizing, plant removal, plant replacement, and miscellaneous related items. Maintenance for the irrigation system includes piping, valves, heads, wiring, electrical controls, and all above and below ground facilities as necessary. Frequency of Performance Inspections occur quarterly unless required more often from an investigation and testing program. The dates of required completion of the inspection reports are the first of the following months: June, September, December, and March. Performance Responsibility Immediate and continuous responsibility for all aspects of the maintenance plan lies with the Board of Directors for the Tenant Association (TA) for Quarry Creek. It is a private organization made up of each of the owners of parcels within Quarry Creek. They bear all costs for the program. Ultimate execution of the maintenance plan lies with the City Engineer at the City of Oceanside. It is their responsibility to monitor the TA's performance of the maintenance plan and to take over the execution of the plan if necessary.