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SDP 08-01; Blue Condominiums; Site Development Plan (SDP) (5)
CIVIL, GEOTECHNICAL, & QUALITY ENGINEERING FOUNDATION DESIGN * LAND SURVEYING * SOIL TESTING MR. BARRY BLUE CLIENT: BLUE RECEIVED PROJECT: BLU 1007-INV DATE: 11 DECEMBER 2007 JA^ 2 3 200B 2950 Ocean Street CITY OF CARLSBAD Carlsbad, CA. 92009 PLANNING DEPT Subject: Preliminary Geotechnical Soil Investigation for the Proposed Residential Construction for the Lot located at 150-152 Cherry Ave., Carlsbad, CA. (APN: 204-231-10) Dear Mr. Blue: Pursuant to your request, we have completed our Preliminary Soils Investigation for the subject site. The purpose of this investigation was to determine the general engineering characteristics of the soils on and underlying the site and to provide specific recommendations for the design parameters for foundations and retaining structures, slab-on-grade floors and site earthwork. The proposed development consists ofthe construction of single/two story, wood framed, stucco type single family residential structures. SITE CONDITIONS The subject site is located approximately 0.1 mile east of Carlsbad Blvd. on the north side of Cherry Avenue. The property is boimded on the north, east and west by existing single family residences and on the south by Cherry Avenue. The site topography consists of an existing level pad falling to the south at approximately 5%. At the time of this investigation, the lot had 2 existing structures to be removed and was partially covered with trees, shrubs and grasses. Based on our visual inspections and observations in the field, and our laboratory test results, the following conclusions were derived. It is our opinion that the subject lot may support the proposed residential structures. However, the conclusions and recommendations found in the latter part of this report shall be incorporated in the design plans and specifications. No geotechnical conditions were encountered which would preclude the development of the site. 1611-A SO. MELROSE DRIVE #285, VISTA, CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 945-4221 Blu 1007-inv FIELD AND LABORATORY TESTING On 6 November 2007, a field investigation was performed at the subject site. This investigation consisted of the excavation of one test pit dug with a backhoe. The detailed Log of the Test Pit is presented on Enclosure (1). As the test pit was advanced, the soils were visually classified by the field Engineer. Undisturbed and bulk samples, as well as in-place density tests, were obtained at various depths representative of the dififerent soils horizons. All samples were retumed to our laboratory for detailed testing. Results of the in-place compaction tests, the Maximum Dry Density Test values for the various soils sampled and the Expansion Potential Test results are presented on Enclosure (2). These materials were also tested for Shearing Strength, Enclosure (3). Shear tests were made with a direct shear machine of the strain control type in which the rate of striain is 0.05 inches per minute. The machine is so designed that tests may be performed ensuring a minimum of disturbance from the field conditions. Saturated, remolded specimens were subjected to shear imder various normal loads. Expansion tests were performed on typical specimens of natural soils. These tests were performed in accordance with the procedures outlined in the Califomia Building Code. SOIL CONDITIONS As indicated by our Test Pit Log, Enclosure (1), the lot is underlain with approximately 6 to 12 inches of topsoil material consisting of dark brown, dry- damp, fine-medium loose silty sand. Underlying the topsoil materials are the Terrace Deposit materials consisting of dark brown, damp, fine-medium dense silty sand. GEOLOGIC HAZARDS According to published information, there are no known active or potentially active faults on or in the immediate vicinity of the subject site. Therefore, the potential for ground rupture at this site is considered low. There are, however, several faults located within a close proximity to this site that the 2 1611-A so. MELROSE DRIVE #285, VISTA, CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 945-4221 UJtii EiUfiMaeoriiUf, Muc. Blu 1007-inv movement associated with them could cause significant groimd motion. The following table presents the distance of major faults from the site, the assumed maximum credible earthquake magnitudes and estimated peak accelerations anticipated at the site. The severity of ground motion is not anticipated to be any greater at this site than in other areas of San Diego County. SEISMICITY OF MAJOR FAULTS MAXIMUM MOMENT SLIP RATE FAULT/TYPE DISTANCE MAGNITUDE(RICHTER) mm/year Rose Canyon (B) > 5 km < 10 km 6.9 1.5 Elsinore-Julian Seg(A) 28 mi. 7.1 5 San Jacinto-Borrego Seg(B) 51 mi. 6.6 4 San Andreas-South-Seg(A) 75 mi. 7.4 24 The following information is presented relative to the subject site and Seismic Zone 4 per the Califomia Building Code, C.B.C: (z) Seismic zone factor = 0.4 Table 16 A-I (Na) Near-source factor =1.0 Table 16 A-S (B) Seismic source type = B Table 16 A-U (Sd) Soil profile type = Sd Table 16 A-J (Ca) Seismic coefficient = 0.44 Na Table 16 A-Q (Cv) Seismic coefficient = 0.64 Nv Table 16 A-R (Nv) Near source factor =1.0 Table 16 A-T LIQUEFACTION POTENTIAL Liquefaction analysis of the soils underlying the site was based on the consideration of various factors which include the water level, soil type gradation, relative density, intensity of ground shaking and duration of shaking. Liquefaction potential has been found to be the greatest where the ground water level is shallow and loose fine sands occur within a depth of 50 feet or less. These conditions are not present within the site area and, therefore, the potential for generalized liquefaction in the event of a strong to moderate earthquake on nearby faults is considered to be low. 3 1611-A SO. MELROSE DRIVE #285, VISTA, CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 945-4221 MMJtMM EiBttinecrhui, Muc. GRADENfG RECOMMENDATIONS Blu 1007-inv Based on field data and our laboratory tests results, the following Conclusions and Recommendations are presented and are to be utilized in conjunction with the Grading and Building Plans: All grading shall be performed in accordance with the applicable recommended grading specifications contained in this report and the City of Carlsbad Grading Ordinance. On the basis of our investigation, development of the site as proposed is considered feasible from a soils engineering standpoint provided that the recommendations stated herein are incorporated in the design of foundation systems and are implemented in the field. Site preparation should begin with the removal of the existing stmctures, any trash, debris, and other deleterious matter. These materials, as well as vegetative matter, are not suitable for use in stmctural fills and should be exported from the site. Also, ariy subsurface stmctures such as cesspools, wells, or abandoned pipelines, which are uncovered during the grading operation, shall be removed or backfilled in accordance with the requirements of the City of Carlsbad. All on-site earth materials are considered suitable for the support of the proposed stmctures. However, prior to constmction or placing fill, the loose surface materials occurring in the area of the proposed stmcture shall be removed to a depth where firm, dense native soils are encountered. The depth of removal is anticipated to be approximately 3 feet below the existing surface. This can be accomplished during the rough grading operation and/or by over-excavating the upper 3 feet of the surface soils to a depth where firm soils are encountered, ripping the exposed bottom surface to a minimum depth of 12 inches, and recompacting the soil to the design grade. All stmctural fill shall be compacted to at least 90% of the maximum dry density at near optimum moisture content as determined in accordance with ASTM Test Procedure D 1557-01. In the event that the finish grade soils expose a transition lot condition; ie, a cut/fill daylight line through the proposed stmcture, the cut portion of the house pad shall be over-excavated and recompacted to a depth of 3 feet below the finished grade. The limits of over-excavation shall extend a minimum of 8 feet outside of the perimeter building foundations. This will provide a uniform fill 1611-A so. MELROSE DRIVE #285, VISTA, CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 945-4221 MMJtMM EMMgiueerhuf, Muc. Blu 1007-inv blanket for an even support of the stmcture and will help mitigate the effects of differential settlement. The site surface materials consist of fine-medium silty sands that are relatively dense in their dry state. These materials are susceptible to erosion. Drainage control is essential to maintain the stability of any planned slopes or slope areas. Site drainage should be dispersed by non-erodible devices in a manner to preclude concentrated runoff over graded and natural areas in accordance with the City of Carlsbad requirements. EXPANSION POTENTIAL In general, the native sandy materials were found to have a very low expansion potential (expansion index EI = 1) according to our Expansion Index Test results. Enclosure (3). Therefore, no additional foundation or slab requirements are considered necessary in regard to soil expansion. Subsequent to rough grading, it is anticipated that the building footings may experience less than 1 inch settlement with less than V2 inch differential settlements between adjacent footings of similar sizes and loads. SOIL SULFATE CONTENT The surface soil was tested for sulfate content by Clarkson Laboratory and Supply, Inc., on November 8,2007. The results of this test indicated that the water soluble sulfate content was found to contain <0.001% (Negligible) per Califomia Test 417 (See Enclosure 4). Therefore, per the 2001 Califomia Building Code, Type II cement with a maximum water-cement ratio of 0.50 and a minimum concrete strength (f c) of 2500 psi should be used for concrete in contact with on-site earth materials. RETAINING WALLS An equivalent fluid pressure of 35 pcf may be used for design of retaining walls with level backfill and 55 pcf for 2H: IV sloping backfill. These figures are based on a drained condition and use of granular backfill having a sand equivalent of 30 or greater. If the native soils are used as backfill, the equivalent fluid pressure of 40 pcf (level) and 60 pcf (2H:1V slope) for active conditions and 60 pcf (level) and 80 pcf (2H:1V sloping) for at-rest conditions can be used. 5 1611-A so. MELROSE DRIVE #285, VISTA, CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 945-4221 MMJtMM Eu0§hMCcriut§t Muc. Blu 1007-inv FOUNDATION DESIGN PARAMETERS For foundation design purposes, the following earth pressures were calculated based on our Shear Test Results (Enclosure 1) from test pit #1 at a depth of 1 to 3 feet below the existing surface and based on a foundation depth and width of 15 inches: (Dark brown, fine-medium silty SAND) Shear Test: Cohesion =100 psf; Angle of Friction =31° Allowable Bearing Value = 1190 psf Equivalent Fluid Pressure = 40 pcf Passive Lateral Resistance = 300 pcf At-rest Pressure = 60 pcf Coefficient of Friction = 0.25 Expansion Index = 1 (Very Low) These values are for dead plus live loads and may be increased by one-third (1/3) for seismic and wind loads where allowed by code. These design bearing values are in accordance with the Califomia Building Code. BUILDING FOUNDATIONS It is recommended that the continuous perimeter foundations and concrete slabs for a light-weight, wood framed stmcture shall be reinforced in accordance with the following minimum designs: a. For slab-on-grade floors: it is recommended that the continuous perimeter foundations for a single story stmcture shall extend a minimum depth of 15 inches and a minimum width of 15 inches into the firm native or compacted fill material as measured from the lowest adjacent grade. A minimum of 18 inches deep by 15 inches wide shall be used for a two story stmcture. b. All foundations shall be reinforced with at least four No.4 steel bars, two bars shall be placed 3 inches from the top of the foundation and the other bars shall be placed 3 inches from the bottom. As an altemative to the 4 steel bars, the contractor may substitute two No. 5 steel bars, one top and one bottom. c. Footings placed on or adjacent to the top of cut or fill slopes shall have a minimum horizontal distance of 7 feet from the bottom edge of the footings to the 6 1611-A so. MELROSE DRIVE #285, VISTA, CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 945-4221 MMJ^MM Eu0iMueeriu0f9 Muc. Blu 1007-inv face of the slope, for slopes less than 20 feet in height. For slopes greater than 20 feet, a horizontal distance of H/3 shall be used where H = height of slope, but need not exceed 40 feet maximum. (See attachment A) d. All interior concrete slabs shall be a minimum of 4 inches in thickness and reinforced with a minimum of No. 3 rebar at 18 inches on center both ways placed in the center of the slab. The bars shall be bent downward into the perimeter footings and wire tied to the foundation steel at 18 inches on center. In order to minimize vapor transmission, an impermeable membrane (ie: 10 mil visqueen) shall be placed over 2 inches of clean, poorly graded, coarse sand, decomposed granite, or cmshed rock. The membrane shall be covered with 2 inches of sand to protect it during constmction and the sand should be lightly moistened just prior to placing concrete. All concrete used on this project shall have a minimum compressive strength of 2500 psi unless otherwise stated on the Building Plans. e. Interior concrete slabs shall be provided with saw-cut joints spaced at a maximum of 10 feet ott center each way within 24 hours after the pour and the saw-cuts shall be 1/4 of the slab tiiickness. It is imperative that the drainage system around the proposed stmcture shall be designed and implemented to provide positive drainage away from all buildings in order td preclude moisture intmsion into the subgrade soils beneath the building foundations and slabs. f Exterior slabs for hardscape, pool decks, walkways, patios, etc. shall be a minimum of 4 inches in thickness and reinforced with a minimum of No. 3 steel rebars at 24 inches on center each way. The reittforcittg steel shall be placed in the upper 1/3 of the slab and held in place with concrete chairs. If imported soil materials are used during grading to bring the building pad to the design elevations, or if variations of soils or building locations are encountered, foundation and slab designs shall be reevaluated by our firm upon the completion of the rough grading operation. LIMITATIONS AND UNIFORMITY OF CONDITIONS The analysis and recommendations submitted in this Report are based in part upon the data obtained from the test pit excavation performed on the site and our experience and judgement. The nature and extent of variations between the 7 1611-A so. MELROSE DRIVE #285, VISTA, CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 945-4221 MMJSrMM Eu0iiuceriu0i^ Muc. Blu 1007-inv test pit and the underlying soils may not become evident until constmction. If variations then appear evident, it will be necessary to re-evaluate the recommendations of this Report. Findings of the Report are valid as of this date; however, changes in conditions of a property can occur with passage of time whether they be due to natural process or works of man on this or adjacent properties. In addition, changes in applicable or appropriate standards occur whether they result from legislation or broadening of knowledge. Accordingly, findings of this Report may be invalidated wholly or partially by changes outside our control. Therefore, this Report is subject to review after a period of one year. In the event that any changes in the nature, design, or location ofbuildings are planned, the conclusions and recommendations contained in this Report shall not be considered valid unless the changes are reviewed and the conclusions of this Report are modified or verified in v^iting. This Report is issued with the understanding that it is the responsibility of the owner or of his representative to ensure that the information and the recommendations contained herein are called to the attention ofthe project Architect and Engineer and are incorporated into the plans. Further, the necessary steps shall be taken to ensure that the contractor and subcontractors carry out such recommendations in the field. It is recommended that our Engineer be provided the opportunity for a general review of the final design plans and specifications for this project in order that the recommendations of this report may be properly interpreted and implemented in the design. It is also recoinmended that our Engineer be provided the opportunity to verify the foimdation and slab constmction in the field prior to placing concrete. (If our Engineer is not accorded the privilege of making these reviews, he can assume no responsibility for misinterpretation of his recommendations). The Engineer has prepared this Report for the exclusive use of the client and authorized agents. This Report has been prepared in accordance with generally accepted soil and foundation engineering practices. No other warranties, either expressed or implied, are made as to the professional advice provided under the terms of this agreement, and included in the Report. 8 1611-A so. MELROSE DRIVE #285, VISTA, CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 945-4221 MMJtMM Eu00iu0^eriu0if ^000^' Blu 1007-inv B&B Engineering Inc. and Associates appreciate this opportunity to be of service. Should you have any questions regarding this project, please do not hesitate to contact us. Sincerely, Stephen B. Peter RCE 38623 Expires 3-31-09 1611 -A so. MELROSE DRIVE #285, VISTA, CA 92081 -5471 Ph: (760) 945-3150 Fax: (760) 945-4221 MM^MM Eiii|iiieeriii<|, Inc EXCAVATED: 11/6/07 PIT DIMENSIONS IN FEET W - 36" SURFACE ELEVATION IN FEET LOG OF TEST PITS BACKHOE_ CASE 580 M L-10' D-6.5' DATUM CLIENT: BLUE PROJECT: BLU 1G07-INV DATE: DEC. 2007 MEAN SEA LEVEL TP- 1 GEOLOGICAL CLASSiFICATION DESCRIPTION o I- _i — Ul z tin as • w m Q. PI CO V) ENGINEERING CUSSIFICATION AND DESCRIPTION TEST DATA: M- D -O (RC) TOP SOIL 0.5 TERRACE DEPOSITS 6.5 10 15 20 GRASS & SILTY SAND TOPSOIL WITH SOME ROOTS, DAMP-MOIST. DARK BROWN FINE-MED SILTY SAND DAMP, DENSE BOTTOM OF TEST PIT AT 6.5' NO CAVING - NO WATER PIT DIMENSION IN FEET W = SURFACE ELEVATION IN FEET L = D = ENCLOSURE(1) Client MR. BARRY BLUE Biii|ineeriiii|, Inc. Project: BLU 1007 INV Date: Dec-07 Test No. Test Date Test Location Test E1/Depth Soli Type Dry Density, pcf Moisture, % Relative Retest Test No. Test Date Test Location Test E1/Depth Soli Type Field Maximum Field Opt. Compaction No. 1 11/6/07 TEST PIT1 @r 1 A 109.8 123.0 7.5 11.0 89 2 11/6/07 TEST PIT 1 @2" 2 A 111.3 123.0 7.4 11.0 90 3 11/6/07 TEST PIT 1 @3* 3 A 113.3 123.0 7.0 11.0 92 COMPACTION CURVE PATA SOIL TYPE AND DESCRIPTION OPTIMUM MOISTURE % MAXIMUM DRY DENSnTY less A. DARK BROWN FINE-MEDIUM SILTY SAND TP-1 @r-6.5' 11.0 123.0 EXPANSION POTENTIAL 1 to 20 = Very Low EXPANSION INDEX = 1 (VERY LOW EXP POTENTIAL) TP-1 @ 1' - 6.5" 21-50 = Low 51-90 = Moderate 91-130 = High 131+ = Critical COMPACTION AND EXPANSION TEST DATA ENCLOSURE (2) 3.5 C 30 i 2.5 (0 W 2.0 1.5 O.S 0.0 Direct Shear Test Results 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.S Confining Pressure (ksf) INTERNAL FRICTION SAMPLE DESCRIPTION • Shear Strength at 0.2 inches of Defomnation * 1 1 W 4.0 4.5 5.0 COHESION INTERCEPT BLU 1007 DARK BROWN F-M SILTY SAND (REMOLDED TO Stiear StrenaOi at 90% OF M.D.) 0.2 inches of Deformation 31 100 JSSO. SOUTHERN CALIFORNIA B&B ENG (BLU 1007) t SOIL & TESTING BY: CA DATE: 11/17/2007 JOB NUMBER: 0712032 APPENDIX i LABORATORY REPORT Telephone (619) 425-1993 Fax 425-7917 Established 1928 CLARKSON LABORATORY AND SUPPLY INC. 350 Trousdale Dr. Chula Vista, Ca. 91910 wvrw.clarksonlab.com ANALYTICAL AND CONSULTING CHEMISTS Date: November 8, 2007 Purchase Order Number: BLU1007 Sales Order Number: 90719 Account Number: B&B To: ! * B&B Engineering 1611-A SO. Melrose Drive #285 Vista, CA 92081 Attention: Dennis P. Beard Laboratory Number: S02871 Customers Phone: 760-945-3150 Fax: 760-945-4221 Sample Designation: *-. * One soil sample received on 11/06/07 taken from Cherry Ave, Carlsbad Job# BLU1007 marked as follows: ANALYSIS: Water Soluble Sulfate California Test 417 Sample S04% Blue Barry 0.001 FIGURE 18A-I-1 2001 CALIFORNIA BUILDING CODE 'FACE OF STRUCTURE TOE OK SLOPE //AW/ \ FACE OF FOOTING HI2 BUT NEED NOT EXCEED 15 FT. (4572 mm) MAX. FIGURE 18A-M—SETBACK DIMENSIONS ATTACHMENT A RECEIVEO OCT 2 \ 2010 CITY OF CARLSBAD STORM WATER MANAGEMENT PLAN PLANNING DEPT FOR BLUE CONDOMINIUMS PROPOSED MINOR SUBDIVISION APN 204-231 - 10 Prepared by: Robert Sukup The Sea Bright Company 4322 Sea Bright Place Carlsbad, CA 92008 760 - 720 - 0098 Prepared For Barry and Mary Blue 2950 Ocean Street Carlsbad, CA 92008 October 20, 2010 TABLE OF CONTENTS INTRODUCTION 1 1.0 Project Description 1 1.1. Hydrological Unit Contribution 1 1.2. Beneficial Use of Coastal Waters 2 1.2.1. Inland Surface Waters 2 1.2.2. Groundwater 2 2.0 CHARACTERIZATION OF PROJECT RUNOFF 2 2.1. Expected Discharges 3 2.2. Soil Characteristics 3 3.0 MITIGATION MEASURES TO PROTECT WATER QUALITY 3 3.1. Construction BMP's 3 3.2. Post construction BMP's 3 3.2.1.1 Appropriate Applications and Siting Constraints 4 4.0 OPERATIONS AND MAINTENANCE PROGRAM 4 5.0 FISCAL RESOURCES 5 ATTACHMENTS A. Vicinity Map B. Project Map with BMPs shown C. Filter Insert Information INTRODUCTION The Stormwater Management Plan [SWMP] requirement Is required for projects that are categorized as a Priority Development Project [PDP] pursuant to the City of Carlsbad Standard Urban Stormwater Management Plan [SUSMP] and Carlsbad's Local Coastal Program requirements. After completing the Storm Water Standards Questionnaire [SWSQ] this project is a PDP. The purpose of this SWMP is to address the water quality impacts from the proposed Improvements for the proposed Blue Condominium project. Best Management Practices [BMP's] will be utilized to provide a long term solution to water quality. This SWMP Is also intended to ensure the effectiveness ofthe BMP's through proper maintenance that Is based on long term fiscal planning. The SWMP is subject to revisions as needed by the engineer. 1.0 Project Description The proposed project is to subdivide an existing lot with a total gross acreage of .16 acres into a 1 Lot 2 Unit Condominium Subdivision. There are presently 2 detached rental homes on the site with a concrete driveway that services both units. The entire site would be cleared ofthe existing older improvements and a new 2 story condominium building with subterranean parking constructed in its place. The proposed project would result in an increase of impervious area by more than 10% as compared to pre-development conditions. 1.1 Hydrologic Unit Contribution The Blue Condominium Project is located in the Carlsbad Hydrologic Unit and more specifically in the El Salto Hydrolic area [unit 4.21 as designated in the San Diego Basin Plan], The project area is characterized by an existing fully developed residential neighborhood of both single family and multiple family homes. The proposed project would have all of the sites water flow to the driveway that services the subterranean parking. The drainage water would enter into a grate inlet that contains a filter insert and trash rack. All filtering would take place at this point. From here, the water would flow to a detention storage pipe for controlled outlet, then to a sump pump for discharge of the filtered water back to the City street. The proposed project will not alter drainage patterns on the site or off site. The stormwater discharge points will not divert runoff from existing conditions. The reality is that any increase in impervious area results in an increase in runoff. Page 1 Through implementation of Low Impact Design practices, such as on site detention in Engineered pipes, the mitigation of additional minor flows is achieved. 1.2 Beneficial Uses of Coastal Waters The beneficial uses for the hydrologic unit are listed below. They have been extracted from the water quality control plan for the San Diego Basin. The only one they I have elaborated on that I feel is appropriate is the REC 1. RECl - Contact Recreation: Includes uses of water for recreation activities Involving body contact with water, where ingestion of water is reasonbly possible. The uses include, but are not limited to, swimming, wading, water skiing, skin and SCUBA diving, surfing, white water activities, or fishing. Other possible benefits indicated in Table 2-3 of the basin plan are Non Contact Water Recreation, Wildlife Habitat, Preservation of Biological Habitats of Special Significance, and Rare-Threatened or Endangered Species of Marine Habitat. 1.2.1 Inland Surface Waters Not Applicable 1.2.2 Groundwater Not Applicable 2.0 CHARACTERIZATION OF PROJECT RUNOFF Per the Carlsbad Local Coastal Program, the Pacific Ocean is considered an Environmentally Sensitive Area [ESA]. This project is not within 200 feet of the Pacific Ocean but it does add more than 2,500 S.F. of impervious surface and increases the existing impervious area by more than 10%. Therefore the project qualifies as a Priority Development Project and is subject to SUSMP treatment BMP standards. According to the California 2006 303d list published by the San Diego Regional Water Quality Control Board, the impaired water body nearest this project is the Pacific Ocean. It's only listed Pollutant Stressor is "Indicator Bacteria" which the proposed project should not contribute to. Page 2 2.1 Expected discharges There is no sampling data available for the existing site condition. The following constituents are sometimes found on small residential developments such as this that could affect water quality. 1. Sediment discharge due to construction activities and post construction areas left bare. 2. Nutrients from fertilizers. 3. Trash and debris deposited in drain inlets. 4. Hydrocarbons from paved areas. 5. Pesticides from landscaping and home use. 2.2 Soil Characteristics The project area is within soil group A, which is a very good draining soil. 3.0 MITIGATION MEASURES TO PROTECT WATER QUALITY To address water quality for the project, BMP's will be implemented during construction and post construction. 3.1 Construction BMP's The construction BMP's that are anticipated to be utilized during construction are as follows: 1. Silt Fence 2. Street Sweeping if needed. 3. Stockpile management 4. Solid waste management 5. Gravel bag berms 6. Concrete waste management 3.2 Post Construction BMP's The project, in its effort to comply with L.I.D. requirements, is designed to have Page 3 all drainage waters filtered by a catch basin insert. A copy of the anticipated filter is in the attachments. The filter insert is designed to treat/filter runoff generated by an 85"^ percentile storm event. For storm events exceeding the 85"^ percentile storm event, runoff will utilize the flow by characteristic of the filter, drain to the detention pipe, then drain to the sump pump for discharge to the street. 3.2.1 Appropriate Applications and Siting Constraints This project is not large in size [.16 acres] but the design accommodates for all ofthe sheet flow run off from rain to go into an insert filter. Some drainage waters will go through landscaped areas and receive some "purification" prior to arriving at the insert. The project has a large basement which "notifies" the designer that intrusion of water into the soil should be minimized. This aspect of the project coupled with a complicated array of deck drains and roof downspouts, makes the filter insert the ideal design. The project has no material storage areas or trash storage areas. There will be a minor irrigation system for the minimum drought tolerant planting. 4.0 OPERATION AND MAINTENANCE PROGRAM The maintenance of the filter insert will be the responsibility of the Homeowner's Association but should be performed by a certified contractor. The maintenance anticipated is as follows: 1. Check the filter for debris and clean as necessary. 2. Replace the filter when necessary. The filter should be inspected in October and February, as a minimum. Any maintenance as described above needs to be done at that time. Additional visits may be necessary if there appears to be a malfunction of the system. The owner may be required to execute a city standard Permanent BMP Maintenance Agreement that records against the property. This agreement outlines the current, prospective and future property owner's obligations to inspect and maintain treatment BMP's on this property to ensure their effectiveness at removing pollutants from this project. Page 4 5.0 FISCAL RESOURCES Funds for maintenance will be paid by the 2 future owners through the Homeowners Association. c This Stormwater Management Plan has been prepared under the direction by the following Registered Civil Engineer: Rdbert O. Sukup ?.o ho Date' Page 5 SITE SBAD LOCATION MAP NO SCALE THOM. BROS. PG. 1106 E-6 Part / GISB MEDIA FILTER-24-41-25 HIGH FLOW FLOW SCHEMATIC STORM BOOM SKIMMER SIDE VIEW BkMedkiGREEN ROtOVAL EFFICIENCIES TM 'uiftmlnf Sifdt SW)»-SSf tee" 85% Tbiot PhoBphonK 69% aauPkmfhoim 41% ObsotM0 Copptr 79% 98% Bbachtd Snc 78% PtuI CotkuM Outtuio 68% JPH 99% Flow Specificotions Description of filter opening Percent Open Total Square Inches per Unit Square Inches of Total Unobstructed Openings Flow Rate (Cubic Feet per Second) Skimmer protected By—Pasa 100X 243.4 243.4 10.0 cfs PERUTE (granular) 40X 354 N/A 76 gpm BloMedlaGREEN (porous blocks) 80X 354 N/A 76 gpm MEDIA TREATED FIOW RATE Total: 76 gpm FLOW RATES BASED ON UNOBSTRUCTCV OPENINGS GRATE •REMOVABLE SCREEN PERLITE BioMediaGREEN BIOSORB UNDERDRAIN BYPASS FINE SCREEN CONCRETE STRUCTURE BOX MANUFACTURED FROM MARINE GRADE FIBERGLASS & GEL COATED FOR UV PROTECTION 5 YEAR MANUFACTURERS WARRANTY PATENTED ALL FILTER SCREENS ARE STAINLESS STEEL summ (mnr Ffmias m BuiT fOi osr aame M€/K DEsiem m BE pmmm miemjcnjRE MB SHOUU) lASr FOR DEDHXS. Kmallz tnfo^btodmarrmrty^tronnnmrttal.rt* BIO CUEAN E:r4\/IROhlMENTAX. SETRV/CE PO BOX aea OCEANSIDE CA 9Z04-a 700—^33—7e-*0 rAX:7eO—4-33—317e BIO CUEAN E:r4\/IROhlMENTAX. SETRV/CE PO BOX aea OCEANSIDE CA 9Z04-a 700—^33—7e-*0 rAX:7eO—4-33—317e GRATE INLET SKIMMER BOX POR MEDIA PILTER TYPE CATCH BASIN INSERT "•""""* DATE: 04-/1 2/04-SCAI-E:Sr — IS "~—• DKAPTER: M.Fi.B. UNITS —INCHES • •' • SSK Bio Clean R-GISB Media Filter with Shelf System I. Specifications Coverage: Ttie Bio Clean R-GISB Media Filter with Shelf System provides fuil coverage of inlets such that all catch basin influent, at rated flows, is conveyed to the filter. The filter wili retain all windblown and swept debris entering the drain. Shelf System: The R-GISB Media Filter is located in the catch basin directly beneath a manhole opening for direct service/access from the manhole. The filter provides a shelf system made of UV protected marine grade fiberglass to direct water flow from the curb inlet to the filter, which is located directly under the manhole. Non-Corrosive Materials: All components ofthe filter system, including mounting hardware, fasteners, support brackets, filtration material, and support frame are constructed of non-corrosive materials (316 stainless steel, and UV/marine grade fiberglass). Fasteners are stainless steel. Primary filter mesh is 316 stainless steel welded screens. Filtration basket screens for coarse, medium and fine filtration is %" x 1 %"expanded, 10x10 mesh, and 35 X 35 mesh with optional 50 x 50 mesh and 200 x 200 mesh, respectively. No polypropylene, monofilament netting or fabrics shall be used in the products. Durability: The R-GISB Media Filter (excluding oil atjsorbent media) and support structures are of proven durability, with an expected service life of 10 to 15 years. The filter and mounting structures are of sufficient strength to support water, sediment, and debris loads when the filter is full, with no slippage, breaking, or tearing. All filters are warranted for a minimum of flve (5) years. Oil Absorbent Media: The R-GISB Media Filter is fitted with an absorbent media on the top perimeter for removal of petroleum hydrocarix»ns firom influent, and so placed in the fliter assembly to treat influent at rated flow. Absorbent media is easily replaceable in the fliter, without the necessity of removing flxed mounting brackets or mounting hardware. Advanced Filtration Media: The R-GlSB is fltted with a combination of advanced filter media to target finer particulates and dissolved pollutants. This filter uses ©cpanded shale for pretreatment followed by a layer of BioMediaGREEN approximately 3 inches thick. This material has the ability to remove dissolved metals, dissolved nutrients, the finest TSS, hydrocarbons and bacteria. Following are the independent third party tested removal efficiencies ofthis material. BioMediaGREEN POLLUTANT Removal Efficiencies Oil & Grease (mg/L) 90% TPH (mg/L) 99% TSS (mg/L) 85% Turbidity (NTU) 99% Total Phosphorus (mg/L) 69.6% Dissolved Metals (mg/L) 75.6% Sil-Co-Sil 106. Mean particle diameter = 19 microns Overflow Protection: The R-GISB Media Filter with Shelf System is designed so that it does not inhibit storm fiows entering the curb inlet, or ot)Struct flow through the catch basin during peak storm flows. Filter Bypass: Water will not bypass the fliter at low flows, nor bypass through attachment and inlet contact surfaces at low flows. Historic Pollutant Removal Efficiency: The R-GISB has been around since 1994. It was originally designed to capture high levels of trash and litter, grass and foliage, sediments, hydrocarbons, nutrients, metals, grease and oil. The below removal efficiencies are averages of several third party independent test performed on the filter since 1994. These tests did not include the BioMediaGREEN or expanded shale. Thus the removal efficiencies ofthe MEDIA FILTER TYPE are much higher, as show above. This table provides further support ofthe longevity and effectiveness of this system. R-GISB POLLUTANT Removal Efficiencies Trash & Litter 90 to 95% Oil & Grease 54 to 96% Sediments/TSS 93.54% Organics 79.3% Total Nitrogen 65 to 96% Total Phosphorus 71 to 96% Non-Scouring: During heavy storm flovra or other flovs« that bypass the filter, the filter screen design prevents washout of debris and floatables in the filter basket. Filter Removal: The R-GISB Media Filter Is readily removable from the mounting/support frame for maintenance or replacement. Removal and replacement of filter screens is accomplished without the necessity of removing mounting bolts, support frames, etc., but by lift out through the manhole. II. Installation Installation: The R-GISB Media Filter will be securely installed in the catch basin or curb inlet opening, with contact surfaces sufficiently joined together so that no filter bypass can occur at low flow. All anchoring devices and fasteners are installed within the Interior ofthe drain inlet The R-GISB Media Filter is located in the catch basin directly beneath a manhole opening for direct service/access from the manhole. The fliter system provides a shelf system to dired water flow from the inlet to the filter, which is located under the manhole. Installation Notes: 1. Bio Clean Environmental Services, Inc notes the Bio Clean R-GISB Media Filter with Shelf System shall be installed pursuant to the manufacturer's recommendations and the details on this sheet. 2. The patented shelf system shall provide coverage of entire inlet opening, including inlet wing{s) where applicable, to direct all flow to basket(s). 3. Attachments to inlet walls shall be made of non-corrosive hardware. 4. Shelf system shall be installed so that the R-GISB Media Filter is located under manhole access. III. Maintenance Maintenance: The R-GISB Media Filter is designed to allow for the use of vacuum removal of captured materials in the filter basket, serviceable by centrifugal compressor vacuum units wrthout causing damage to the filter or any part of the mounting and attachment hardware during normal cleaning and maintenance. R-GISB Media Filter can be cleaned and vacuumed from the manhole-opening. Entering the catch basin to clean the filters is not necessary. Ail filters not accessible from the manhole will be rejected Maintenance Notes: Bio Clean Environmental Services, Inc. recommends cleaning and maintenance ofthe Bio Clean R-GISB Media Filter with Shelf System a minimum of two times per year or following a significant rain event that would potentially accumulate a large amount of debris to the system. The hydrocartaon boom should be replaced a minimum of twice per year or at each service as needed. The advanced filtration media should be replace a minimum of once per year. Varies upon loading. Any person periforming maintenance activities that require entering the catch basin or handle a toxic substance have completed the proper training as required by OSHA. Remove manhole lid to gain access to R-GISB Media Fitter with Shelf System. The R-GISB Media Filter should be located directly underthe manhole lid. Under normal conditions, cleaning and maintenance ofthe R- GISB Media Filter with Shelf System will be performed from above ground surface. Special Note: entry into an underground manhole, catch basin and stormv^^ater vault requires training in an approved Confined Space Entry Program. Remove all trash, debris, organics, and sediments collected by the R-GISB Media Filter with Shelf System. Removal of the trash and debris can be done manually or with the use of a vactor truck. Manual removal of debris may be done by lifting the R-GISB Media Filter from the shelf and pulling the R-GISB Media Filter from the catch basin and dumping out the collected debris. 6. Any debris located on the shelf system can be either removed from the shelf or can be pushed into the R-GISB Media Filter and retrieved from R-GISB Media Filter. 7. Evaluation ofthe hydrocarbon boom shall be performed at each cleaning. Ifthe boom is filled with hydrocarbons and oils it shoukJ be replaced. Removed boom by cutting plastic ties and remove boom. Attach new boom to basket with plastic ties through pre-drilled holes in basket. 8. Place manhole lid back on manhole opening. 9. Transport all debris, trash, organics and sediments to approved facility for disposal in accordance with local and state requirements. The hydrocarbon boom with adsorbed hydrocarbons is considered hazardous waste and need to be handled and disposed of as hazardous material. Please refer to state and local regulations for the proper disposal of used motor oil/filters. 10. Following maintenance and/or inspection, the maintenance operator shall prepare a maintenance/inspection record. The record shall include any maintenance activities performed, amount and description of debris collected, and condition of filter. The owner shall retain the maintenance/inspection record for a minimum of five years fi'om the date of maintenance. These records shall be made available to the governing municipality for inspection upon request at any time. 11. Any toxic substance or item found in the fliter is considered as hazardous material can only be handled by a certified hazardous vvaste trained person (minimum 24-hour hazwoper). BIO CLEAN M ENVIRONMENTAL SERVICES, INC.Ii^F P O Box 869, Oceanside, CA 92049 (760 433-7640 Fax (760) 433-3176 www.biocleanenvironmental.net RECEIVED OCT 2 1 2010 CITY OF CARLSBAD PLANNING DEPT DRAINAGE REPORT FOR BLUE CONDOMINIUMS PROPOSED MINOR SUBDIVISION MS - 08 - 01 APN 204-231 - 10 PREPARED FOR Barry and Mary Blue 2950 Ocean Street Carlsbad, CA 92008 PREPARED BY Robert O. Sukup 4322 Sea Bright Place Carlsbad, CA 92008 760-720-0098 October 20, 2010 The proposed project is to subdivide an existing lot with a total gross acreage of .16 acres into a 1 Lot, 2 Unit Condominium Subdivision. There are presently 2 detached rental homes on the site. The density of the project will remain the same but the use will be greater from a drainage standpoint. The attached hydrology calculations show a small increase of drainage waters from the proposed project. This is due to the increase in impervious surface. Basically all of the storm water is intended to flow to the subterranean parking driveway where it will first flow into a grate catch basin with a filter insert, then to a detention pipe, and finally to a sump pump to be pumped up to the street. The detention [storage] pipe has been designed to hold back the projected increase in flow [.21 cfs] for a minimum of 5 minutes. The 5 minutes is the Time of Concentration I used in my calculations for the anticipated Peak Hydrology Event for this lot. The amount of flow coming out of the detention pipe will be restricted by the outlet pipe size and not allow more than the pre deveiopment flow [.60 cfs] to be released. The detention pipe as presently shown on the plans has more capacity than needed and may be reduced in size in the final design. The discharge from the sump pump will go up to a proposed "dispersion box" and then through a D-25 outlet to Cherry Avenue. Cherry Avenue is the project frontage street where all the site's water presently goes. Once in Cherry Avenue, the water flows westward in the existing curb and gutter for about 200' or so until it enters the City's storm drain system in Carlsbad Boulevard. From there it ultimately makes its way to the Pacific Ocean via the City's system. In my professional opinion, the drainage concept I have proposed will work very well and not cause any offsite siltation, erosion, or flooding. Adequate room for modification in final design has been allowed for. SITE SBAD LOCATION MAP NO SCALE THOM. BROS. PG. 1106 E-6 HVDROLOey cALCS SO\LTyPS- A (pEie3^T-^^Z-C0UW-rV HyDROi.OG\C soiLhAP - ^A^J LUIS Rev) po^ - * S'S, T^\5 \S A SM/iLL INFILL tOT (^60V iS-^.S'") , POK. BOTf^- PR£ t K)5T GOhODlTlOKlS I AM U^^W^ A T^' BlV^lM- TRAVEL LeM<^Ti^s AResKioRT ^ -me p^e DeVELomeAjr UAS A uoMC CONC. pRive^Q/^V aJ^flc^j ^Moves'-Tl^i^ uoATei^. OUT (S^uicicty AREA - • IC? ACRES. TO OFFSET TUE TWeoR&TlC^L /MCRB^^e, X WAVE PR0P05&D OK) ^ITG: DeTBIOT^OM IM 30' OP 3^'^ pipe TO V^OLD BAc:^ TVI£ IN/^P£45£ //O F^0(AP pO/^ TUE PBAK e-VEf^T L«'.- 5MiSl- Tfc :30' OP S^" PIPB f^iQ^ A MAXIMUM SToe/^G£ cAPAoiTV OF ^l^c-e ojmcU is MUCI4 M/eGe|l TH/^h) IN FW4L D&Si^N- Tl4t oUTPLOu; FROM TVIE DeT^/Oj/O^j PlPe U)iCL He L/MiTfet] TO *40c-f5 oeSIC/O op^ OUTPLOLO PIPES TO TU£ 3UMP PUMf |SASIN, rU/qT UJILL POMP THE Pf^iK)4ce tA)4Te.R B4cicl up TD San Diego County Hydrology Manual Date: June 2003 Section: Page: Table 3-1 RUNOFF COEFFICIENTS FOR URBAN AREAS 3 6 of 26 Land Use Runoff Coefficient "C" Soil Type NRCS Elements County Elements % IMPER. B C D Undisturbed Natural Terrain (Natural) Permanent Open Space 0* 0.20 0.25 0.30 0.35 Low Density Residential (LDR) Residential, 1.0 DU/A or less 10 o:'? 0.32 0.36 0.41 Low Density Residential (LDR) Residential, 2.0 DU/A or less 20 0.34 0.38 0.42 0.46 Low Density Residential (LDR) Residential, 2.9 DU/A or less 25 0.38 0.41 0.45 0.49 Medium Density Residential (MDR) Residential, 4.3 DU/A or less 30 0.41 0.45 0.48 0.52 Medium Density Residential (MDR) Residential, 7.3 DU/A or less 40 0.48 0.51 0.54 0.57 Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 0.54 0.57 0.60 Medium Density Residential (MDR) High Density Residential (HDR) Residential, 14.5 DU/A or less Residential, 24.0 DU/A or less 65 0.66 0.58 0.67 0.60 0.69 0.63 0.71 High Density Residential (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77 0.78 . 0.79 Commercial/Industrial (N. Com) Commercial/Industrial (G. Com) Neighborhood Commercial General Commercial ' 85 0.80 0.77 0.80 0.78 0.81 0.79 0.82 Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 0.84 0.85 Commercial/Industrial (Limited L) Limited Industrial 90 0.83 0.84 0.84 0.85 Commercial/lndustriai (General 1.) General Industrial 95 0.87 0.87 0.87 0.87 •The values associated with 0% impervious may be used for direct calculation of the nmoff coefficient as described in Section 3.1.2 (representing the pervious runoff coefficient, Cp, for the soil type), or for areas that will remain undisturbed in perpehiity. Justification must be given that the area will remain natural forever (e.g., the area is located in Cleveland National Forest). DU/A = dwelling units per acre NRCS = National Resources Conservation Service 3-6 V County of San Diego Hydrology Manual Rainfall Isopluvials 100 Year Rainfall Event - 6 Hours Isopluvlal (inches) ^•GIS SaTi-GIS ^XL Have .S-jn I'hc^t (^nvTcd! tms M»P IS TOOVIDED WITHOUT WARRANTY OF AW hM>. eTHEK EXMCU OR IMPIKD. IMaUOKM. Bt'I NOI IMIE010. TIC MPICO WARRWHES OF MRT MANTABWtV ANP TOMesS FOR A WTKUUW fWWOM. Copyri^ IvtGIS. M R^^ Raw»««. 3 0 3 Miles County of San Diego Hydrology Manual Rainfall Isopluvials 100 Year Rainfall Event - 24 Hours Isopluvlal (Inches) :>pw iGIS ^•.^m o« MPtKn wciuDiNo. tin MOT LMTCO Ta »«l-nK wA^wmiB ANO rnNMs FOU A i-WTiorS WRJSST^ CopyitaMtvCIS. IRqhliNawr.M. 3 0 3 Miles o o 40 60 1 Duration 9 4 s e Hours Directions for AppBcation: (1) From predpitation maps detertnlrje 8 hr and 24 hr amounts for the setected (if«quency. These maps ars Included lit the County Hy<to)agy Manual (to, SO, and 100 yrtnaps fnciuded in the Desfgn ami Procedure Manual). (2) Adjust 6 iir precipitatloii (ff necessary) so that It Is wtthfn the range of 45% to 65% of the 24 tir precipilaSon <not applicaple to Desert). (3) Plot e hr precipitation on the right side of the chart. (4) Draw a Itne through the point parallel to the pidSeA Ibtes, (5) This line Is ttie Intensity-duration curve for the location bei! : •!• r-lyzed. Application Form: (a) Selected frequency IQO year (b) Pg = in.. P24 = 4 5 = %P> (0) Adjusted Pgf2)s 2-5 in. {d)t„~ 5 roir», (e)l=^ In./hr. '24 Note: This chart replaces the Intensity-Duration^Frequency curves used since 1965. i '"1 2 2.S 3-lis'' «-1 B .-_ is « i '"1 1 1 1 i 1^ i 1 1 B .-_ is « s Z1...S1 19 isa aiF LfflT ios Ifs 'zM ,6.27 f,„ 6.S» siso ias4 11.86 iai7 l44S is:si fpi loTil s Z1...S1 19 isa aiF LfflT ios Ifs 'zM ,6.27 f,„ 6.S» siso l3B[7,42 8.4S 6,74 S.S4 IW laso "8.42 11,66 "s.w is:si fpi loTil s Z1...S1 19 isa aiF LfflT ios Ifs 'zM 3.57 Tos j slo 8.4S 6,74 S.S4 IW laso "8.42 11,66 "s.w is:si fpi loTil 1S 30 40 — 120 ~m " " IM 1.30 om "oOS" OW ara" 0.41 0.34' "6:» \M i'M <l40 ii* 1.03 0.% 6.80 ait o-si 6M oM 2.S9 FlS 1.97 i.se rss T.ii ros O.is 0.62 13.24 "Wt "z'M 2.0/ IM. 1.48 TM m "6m 0.73 ores ats|4,e4i m\m $.19 x^r 6.S4 4.86 , r,«3 W 148 1S 30 40 — 120 ~m " " IM 1.30 om "oOS" OW ara" 0.41 0.34' "6:» \M i'M <l40 ii* 1.03 0.% 6.80 ait o-si 6M oM 2.S9 FlS 1.97 i.se rss T.ii ros O.is 0.62 13.24 "Wt "z'M 2.0/ IM. 1.48 TM m "6m 0.73 ores 2.49'f2",So Eor 2.41 tai "Cas lisatC^ Toa'ii'o arawWi .Ml. a.aa 878 'iM' 1-3S i.TB IM 4.20 lC7i "9.16 '2,69 ~m s.1a "a1i8 'm' lies & •STf •"2.46 1S 30 40 — 120 ~m " " IM 1.30 om "oOS" OW ara" 0.41 0.34' "6:» \M i'M <l40 ii* 1.03 0.% 6.80 ait o-si 6M oM 2.S9 FlS 1.97 i.se rss T.ii ros O.is 0.62 13.24 "Wt "z'M 2.0/ IM. 1.48 TM m "6m 0.73 ores 2.49'f2",So Eor 2.41 tai "Cas lisatC^ Toa'ii'o arawWi .Ml. a.aa 878 'iM' 1-3S i.TB IM 1.53 t.3Z i.i8 ,1.70 T.47 f.si 1.87 1.186" 2.04 "i.7i 1^7 UO 0.93 0,43 aeglo^s 0.87 aes t,Ofl US f.30 o.ia o.if [0.28 o5s a3& 0]33 Q.soro.se 0.7S 0.67' d.8S ,0.U OM^ 1.63 1.13 F I G V ft R Intensity-Duration Destgn Chart - Template LOT fi 6 0 « o o lo art SEE SHT 3 FOR SURFACE DRAINS