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HomeMy WebLinkAboutMS 16-01; PACIFIC WIND; INFILTRATION FEASIBILITY INVESTICATION, MAGNOLIA AVENUE APARTMENTS, CARLSBAD, CALFORNIA; 2015-06-23LOR GEOTECHNICAL GROUP, INC. Soil Engineering • Geology .A. Environmental INFILTRATION FEASIBILITY INVESTIGATION MAGNOLIA AVENUE APARTMENTS CARLSBAD, CALIFORNIA PROJECT NO. 33090.12 JUNE 23, 2015 Prepared For: Harding Street Neighbors 14211 Yorba Street, Suite 200 Tustin, California 92780 Attention:Mr. Todd Cottle 6121 Quail Valley Court .._ Riverside, CA 92507 .._ (951) 653-1760 .._ (951) 653-1741 (Fax) .._ www.lorgeo.com 19-438 Ruppert Street .._ P.O. Box 580799 .._ N. Palm Springs, CA 92258 .._ (760) 329-2727 .._ (760) 329-2626 (Fax) LOR GEOTECHNICAL GROUP, INC. Soil Engineering • Geology A Environmental Harding Street Neighbors 14211 Yorba Street, Suite 200 Tustin, California 92780 Attention: Mr. Todd Cottle June 23, 2015 Project No. 33090. 1 2 Subject: Infiltration Feasibility Investigation, Magnolia Avenue Apartments, Carlsbad, California. LOR Geotechnical Group, Inc. is pleased to present this report summarizing the results of our constant head infiltration testing recently conducted within the proposed infiltration areas for the proposed multi-family residential project, Magnolia Avenue Apartments, located at the southeast corner of Magnolia A venue and Jefferson Street in the City of Carlsbad. INTRODUCTION Information provided by Mr. John Dykes of So Cal Civil Solutions, Inc. indicates that infiltration basin facilities and vegetated swales will be used for the infiltration of onsite runoff waters for the proposed multi-family residential project. The location and elevations of the proposed facility were indicated to us via email by Mr. Dykes and illustrated on a Conceptual Drainage and Improvement Plan, Sheet C-2 prepared by So Cal Civil Solutions, Inc. (2014). This firm previously conducted a preliminary geotechnical investigation for the project in 2014 (LOR, 2014). During that investigation, 4 exploratory borings were advanced to a maximum depth of approximately 51 feet at the site. Groundwater was encountered at a depth of approximately 21 feet beneath the ground surface. In addition, 2 constant head infiltration tests were conducted. These tests found infiltration rates of 0. 7 to 12. 7 inches per hour at depths of approximately 3 feet. Our previous borings placed within the currently prop_osed infiltration areas noted the presence of relatively granular materials beginning at depths of approximately 10 and extending to depths of approximately 15 feet. The purpose of this current investigation was to determine the infiltration characteristics of the granular soils previously noted at a depth of approximately 1 0 feet. 6121 Quail Valley Court • Riverside, CA 92507 • (951) 653-1760 • (951) 653-1741 (Fax) • www.lorgeo.com 19-438 Ruppert Street • P.O. Box 580799 • N. Palm Springs, CA 92258 • (760) 329-2727 • (760) 329-2626 (Fax) Harding Street Neighbors June 23, 2015 INFILTRATION TESTING AND TEST RESULTS Project No. 33090.12 A total of 3 constant head infiltration tests were conducted at the proposed infiltration locations approximately illustrated on the enclosed Infiltration Test Location Map, Enclosure 1. The constant head infiltration testing was conducted to minimize disturbance to existing improved areas of the site due to the proposed depth for infiltration, 10 feet. Testing consisted of a test hole which was excavated using a hollow stem auger drill rig to a depth of approximately 1 0 feet below the existing ground surface. The holes were 8-inches in diameter. Two inches of gravel was placed in the bottom of the holes and perforated plastic liner was placed into the hole. A 2-inch diameter PVC pipe with a preset water level of 0.5 feet was inserted into the liner. A 5-gallon, glass bottle was then inverted over the pipe with a vacuum seal in order to maintain a constant 0.5 feet of water within the hole. The volume of water used in a given time period was recorded at various time intervals to establish the percolation rate. This rate was then converted to an infiltration rate. Our clear water infiltration test results are summarized in the following table: Test No. Depth (ft.)* Percolation Rate Infiltration Rate (gal/sf/day) in/hr P-3 10 25.3 1.7 P-4 10 11.1 0.7 P-5 10 10.8 0.7 * depth measured below existing ground surface The results of our percolation testing are attached as Enclosures 2 through 7. SUBSURFACE EXPLORATION As previously mentioned, this firm conducted 4 exploratory borings at the site in 2014. These borings were advanced to depths of approximately 19.5 to 51 feet below the existing ground surface in the general location of the proposed infiltration. The approximate location of these previous borings is illustrated on Enclosure 1. As noted within these borings, the surface of the site contained a relatively thin layer of fill materials. These materials were noted to generally consist of silty sand with 2 LOR GEOTECHNICAL GROUP, INC. Harding Street Neighbors June 23, 2015 Project No. 33090.12 gravel which was dark brown in color, damp, and in a relatively dense state. This unit was noted to range from approximately 2 to 5 feet in thickness. Underlying the surticial fill materials, natural units of alluvium were encountered. These materials generally consisted of well graded sand with gravel, and cobbles and minor units of silty sand, sandy silt, and clayey sand. In general, the alluvial materials were red- brown in color. Groundwater was encountered at a depth of approximately 21 feet beneath the ground surface. No bedrock was encountered within our exploratory borings as advanced to a maximum depth of approximately 50 feet. Copies of the logs of our previous borings are present as Enclosures 8 through 11 . In order to estimate the approximate depth to both current and historic groundwater in this area, a search was conducted for water wells on both the California Department of Water Resources and U.S.G.S. National Water Information System online databases. No wells were indicated in the nearby site region tor either database. We contacted the Vallecitos Water District, the water supplier for the site and surrounding area, for groundwater information in the region surrounding the site. They indicated that they do not keep well records. CONCLUSIONS Based upon our current test data reported herein, clear water infiltration rates in the general areas currently proposed for infiltration range from 0. 7 to 1 . 7 inches per hour. The rates obtained during this investigation are clear water rates. An appropriate factor of safety should be applied to the rate for storm water. A typical factor of safety for such is 2.0 to 3.0. The system should be designed and constructed as outlined within the recommendations contained within this report and any other jurisdictional agency requirements. Separation between the bottom of the system and groundwater should be evaluated by the project engineer in accordance with current jurisdictional agency requirements. Systems should be set back a distance from improvements as to not have an adverse affect in those improvements. If utilized, geotextile tilter fabric utilized should consist of such that it prevents soil 3 LOR GEOTECHNICAL GROUP, INC. Harding Street Neighbors June 23, 2015 piping but has greater permeability than the existing soil. Project No. 33090.12 During site development, care should be taken as not to disturb the area{s) proposed for infiltration as changes in the soil structure could occur resulting in a change of the soil infiltration characteristics. To ensure continued infiltration capability of the infiltration area, a program to maintain the facility should be considered. This program should include periodic removal of accumulated materials, which can slow the infiltration and decrease the water quality. Materials to be removed from the infiltration areas typically consist of litter, dead plant . matter, and soil fines {silts and clays). Proper maintenance of the system is critical. A maintenance program should be prepared and properly executed in accordance with jurisdictional agency requirements. Should you have any questions regarding this report, please do not hesitate to contact us at your convenience. Respectfully submitted, LOR Geotechnical Group, Inc. AAT:JPL/ejt Enclosures: Distribution: Enclosure 1: Infiltration Test Location Map Enclosure 2 through 7: Constant Head lnfiltrometer Test Data Enclosures 8 through 11 : Boring Logs Addressee (2) and via email todd@c-cdev.com So Cal Civil Solutions via emaii john@socaiciviisoiutions.com 4 LOR GEOTECHNICAL GROUP, INC. REFERENCES California Department of Water Resources, Water Data Library, http://www. water .ca. gov /w aterdatalibrary I LOR Geotechnical Group, Inc., 2014, Preliminary Geotechnical Investigation, Proposed Multi-Family Residential Project, Carlsbad Apartments, APN's 204-292-01, -02, -10 through -14, -16 through -22, 204-291-14, -16, 17, and -19 through -27 ., Carlsbad, California, Project No. 33090.1, dated July 31, 2014. So Cal Civil Solutions, Inc., 2014, Conceptual Drainage and Improvement Plan, C-2, dated December 5, 2014. USGS, National Water Information System, Web Interface, http://waterdata.usgs.gov/usa/nwis/gw. LOR GEOTECHNICAL GROUP, INC. INFILTRATION TEST LOCATION MAP ENCLOSURE: DATE: SCALE: 1 JUNE 2015 PROJECT: CLIENT: LOR Geotechnical Group, Inc. PROJECT NO: § MAGNOLIA AVENUE APARTMENTS, CARLSBAD, CA.33090.12 HARDING STREET NEIGHBORHOODS, LLC.P-1P-3B-2B-1B-3B-4P-5P-2Legend(Locations Approximate)Map SymbolsB-4 - Exploratory Boring Location (LOR, 2014)P-2 - Infiltration Test Location (LOR, 2014)P-5 - Infiltration Test Location (This Investigation)P-4 II CONSTANT HEAD INFILTROMETER TEST DATA II Project: Magnolia Avenue Apartments Test Date: June 16, 2015 Project No.: 33090.12 Test Hole No.: P-3 Soil Classification: (SP) Poorly Graded Sand Test Hole Size: 6" X 8" Depth of Test Hole: 10 ft. Date Excavated: June 16, 2015 Tested By: Josh TEST PERIOD TIME TOTAL WATER WATER INFILTRATION INFILTRATION TRIAL NO. TIME INTERVAL ELASPED TIME USED USED RATE REMARKS (minutes) (minutes) (lbs.) Caal) (gal/sf./day) RATE (in/hr) s 8:35 Refilled 1 36 36 23.82 2.86 66.1 4.4 E 9:11 s 9:56 Refilled 2 90 126 24.21 2.91 26.9 1.8 E 11 :26 s 11 :50 3 31 157 4.63 0.56 14.9 1.0 E 12:21 s 12:21 4 29 186 7.79 0.94 26.8 1.8 E 12:50 Enclosure 2 TEST PERIOD TIME TOTAL WATER WATER INFILTRATION INFILTRATION TRIAL NO. TIME INTERVAL ELASPED TIME USED USED RATE RATE (in/hr) REMARKS (minutes) (minutes) (lbs.) (gal) (aal/sf./day) s 12:50 5 36 222 9.51 1.14 26.4 1.8 Refilled E 1:26 s 2:05 6 60 282 15.23 1.83 25.3 1.7 E 3:05 Enclosure 2 continued Infiltration Rate Versus Time P-3 20 "i:" 18 :::s 0 16 .c: ._ ti) 14 i Q) .c: 0 12 C: ·-.._.. Q) 10 ..... co 0::: 8 C: 0 6 ·-..... co s... 4 ..... -·-'I- C: 2 - 0 0 36 126 157 186 222 282 I Elasped Time (min.) I Enclosure 3 II CONSTANT HEAD INFILTROMETER TEST DATA I\ Project: Magnolia Avenue Apartments Test Date: June 16, 2015 Project No.: 33090.12 Test Hole No.: P-4 Soil Classification: (SP) Poorly Graded Sand Test Hole Size: 6" X 8" Depth of Test Hole: 10 ft. Date Excavated: June 16, 2015 Tested By: Josh/ MT TEST PERIOD TIME TOTAL WATER WATER INFILTRATION INFILTRATION TRIAL NO. TIME INTERVAL ELASPED TIME USED USED RATE RATE (in/hr) REMARKS (minutes) (minutes) (lbs.) (gal) (gal/sf./day) s 9:11 1 64 64 24.91 2.99 38.9 2.6 Refilled E 11 :15 s 12:11 2 84 148 9.67 1.16 11.5 0.8 Refilled E 1:35 s 2:21 3 90 238 10.02 1.20 11.1 0.7 E 3:51 Enclosure 4 20 "i:" 18 :::s 0 16 .c ........ 1/) 14 Q) .c: (.) 12 C: ·--Q) 10 ...., ca ct: 8 C: 0 6 ·-...., ca "-4 ...., ·-'+-C: 2-- 0 Infiltration Rate Versus Time P-4 0 64 148 Elasped Time (min.) I 238 I I Enclosure 5 II CONSTANT HEAD INFILTROMETER TEST DATA II Project: Magnolia Avenue Apartments Test Date: June 16, 2015 Project No.: 33090.12 Test Hole No.: P-5 Soil Classification: (SP) Poorly Graded Sand Test Hole Size: 6" X 8" Depth of Test Hole: 10 ft. Date Excavated: June 16, 2015 Tested By: AAT TEST PERIOD TIME TOTAL WATER WATER INFILTRATION INFILTRATION TRIAL NO. TIME INTERVAL ELASPED TIME USED USED RATE REMARKS (minutes) (minutes) (lbs.) Caal} (aal/sf./dav) RATE (in/hr) s 9:46 1 50 50 1.99 0.24 3.9 0.3 E 10:36 s 10:36 2 52 102 5.13 0.66 9.9 0.7 E 11 :28 s 11 :28 3 36 138 8.84 1.58 23.5 1.6 Refilled E 12:04 s 12:51 4 55 193 6.38 0.78 11.6 0.8 E 1:46 Enclosure 6 TEST PERIOD TIME TOTAL WATER WATER INFILTRATION INFILTRATION TRIAL NO. TIME INTERVAL ELASPED TIME USED USED RATE RATE (in/hr) REMARKS (minutes) (minutes) (lbs.) (gal) (gal/sf./dav) s 1:46 5 45 238 4.98 0.74 11.1 0.7 Refilled E 2:31 s 3:22 6 30 268 3.25 0.39 10.8 0.7 E 3:52 Enclosure 6 continued Infiltration Rate Versus Time P-5 20 "C' 18 - ::::J 0 16 -.c ....... "' 14 -Q) .c (.) 12 -C: ·--Q) 10 -...., ca 0::: 8 - C: 0 6 -...., ca s... 4-...., -·-.... C: 2 -- 0 0 50 102 138 193 238 268 Elasped Time (min.) Enclsoure 7 ~ "' TEST DATA VJ f-f-z f-VJ VJ [.LJ [.LJ f-[.LJ f->-[.LJ >-[.LJ z f-z t:: c... >-v LOG OF BORING B-1 Ii.. ::i >-0 z G.:' f-0 VJ 3 f-0 ~ u~ [.LJ ....J 0 c... u 0 [.LJ~ [.LJ \.) ....J 0 ::r: V) :3: f-~~ Cl~ c... ::r: Cl"! f--< :J >-~ t:: :J c... 0 ~ f-~ -< LU ....J 0 VJ Cl ....J Cl i::o i::o 6 VJ -< ....J ::E DESCRIPTION 0 ~ SM @0' FILL: SILTY SAND, approximately 5% gravel to 1/2", I ~ _.,.. 20% coarse grained sand, 25% medium grained sand, 30% II 2.9 109.8 ~ SM l fine !!rained sand 20% siltv fines li!!:ht brown. drv. loose. I 5 @ 2' ALLUVIUM: SIL TY SAND, approximately 10% coarse II 3.9 l07.2 I ,'--,-":-SP grained sand, 30% meidum grained sand, 40% fine grained sand. 20% siltv fines brown damn. 32 13.9 119.9 I SC @ 5' POORLY GRADED SAND, approximately 30% medium grained sand, 65% fine grained sand, 5% silty fines, light red 10 24 13.2 118.5 I brown damn. @ 7' CLAYEY SAND, approximately 20% coarse grained sand, 25% medium grained sand, 25% fine grained sand, 30% clayey fines of low plasticity, red brown, moist. 15 @ 10' becomes gray. 25 for 3" 21.4 l04.1 ■ @ 15' becomes wet, slightly coarser grained. 20 128 for 3" 23.4 98.3 ~ @20' alternating layers of CLAYEY SAND and POORLY GRADED SAND, 2 to 5" thick. @21' groundwater. 25 "" "" 63 for 3" 15.l CL @25' LEAN CLAY with SAND, approximately 15% medium grained sand, 30% fine grained sand, 25% clayey fines of low plasticity, gray, damp. 30 67 for 3" 19.7 ~ ~ SM @30' SIL TY SAND, approximately 15% coarse grained sand, 30% medium grained sand, 30% fine grained sand, 25% sitly fines with trace clay, gray, wet. 35 67 for 5" 12.3 lO Xl 40 "'= 67 for 3" 21.4 ',' SP @40' POORLY GRADED SAND with SILTY, approximately SM 10% coarse grained sand, 40% medium grained sand, 40% ,' fine grained sand, 10% silty fines, gray white, wet. ' ' 45 67 for 3" 15.6 "' "" 50 "' = 67 for 3' 12.6 END OF BORING Fill 0-2' 55 Groundwater@ 21' No Bedrock Boring backfilled with bentonite 60 PROJECT: Proposed Multi-Family Residential Project PROJECT NUMBER: 33090.1 CLIENT: Harding Street Neighbors, LP ELEVATION: NA DATE DRILLED: July 8, 2014 LOR GEOTECHNICAL GROUP INC. EQUIPMENT: CME75 HOLE DIA.: 8" I ENCLOSURE: B-1 Ir.. Enclosure 8 ... r TEST DATA f/l f-f-z f-f/l f/l UJ LJJ f-UJ f->-UJ >-LJJ z f-z t: c.. >-Q LOG OF BORING B-2 u... ::i >-0 ;2 ~ f-0 f/l ~ f-0 c::: U,--:-UJ ....l ~ c.. u 0 UJ a:. wv ....l 0 :r: f/l ;$ f-c::: ~ Cl e:_ c.. ::c: ~ f-<l'. ::) >-2 t: ::) c.. 0 c::: f-c::: <l'. LJJ ....l 0 (/) Cl ..J Cl O'.l O'.l 0 f/l <l'. ..J 2 DESCRIPTION 0 SM @ 0' FILL: SIL TY SAND, approximately 35% medium grained sand, 40% fine grained sand, 25% sitly fines, brown, dry, loose. ~~· 15 5.9 114.5 I ~ SM @2' ALLUVIUM: SILTY SAND, approximately 40% medium ~ grained sand, 30% fine grained sand, 30% silty fines, red brown, dry. 5 9 6.3 105.4 I @ 5' SIL TY SAND, approximately 35% medium grained sand, 40% fine grained sand, 25% silty fines, red brown, dry, micaceous. 16 6.8 103.8 I 17' SP @ 7' POORLY GRADED SAND with SILT, approximately ,,, •' SM 40% medium grained sand, 50% fine grained sand, 10% silty , ,• fines, red brown, damp. , , , ,• 10 36 6.9 106.9 I ~~:, SP @ 10' POORLY GRADED SAND, approximately 15% medium ,,, ,• grained sand, 80% fine grained sand, 5% silty fines, speckled ,, black-brown, damp. , , ,• , , .. ··:. ·.:-:.·. 15 ,-~~ 34 17.0 114.8 I SM @ 15' SILTY SAND, approximately 10% coarse grained sand, 25% medium grained sand, 50% fine grained sand, 15% silty fines, red brown, wet. @ 16' becomes gray white, trace clay. 20 128 for 3" 12.6 103.8 I END OF BORING Fill 0-2' No groundwater No bedrock Boring backfilled with bentonite 25 PROJECT: Proposed Multi-Family Residential Project PROJECT NUMBER: 33090.1 CLIENT: Harding Street Neighbors, LP ELEVATION: NA DATE DRILLED: July 8, 2014 LOR GEOTECHNICAL GROUP INC. EQUIPMENT: CME75 HOLE DIA.: 8" I ENCLOSURE: B-2 \.. . Enclosure 9 ~ r TEST DATA (/J f-f-z f-(/J (/J Ul Ul f-Ul f->-Ul >-f-f-0.. Ul z z (/) ?-CJ LOG OF BORING B-3 u. ::i >-0 ui f-0 O:'. u~ zG::' :-0 ~ z LU ..J 0.. u 0 LU -;ft_ LU u 0 :r: (/J :3: f-c,::-a~ ..J (/J -< 0.. :r: f-::i >-~ f-::J 0.. 0 O:'. f-O:'. -< :i Ul ..J 0 (/J Cl a Ill Ill 6 (/J -< ...J ~ DESCRIPTION 0 ~~ PT L1m 0' SOD e'---'-SM @0' TOPSOIL SILTY SAND, approximately 10% coarse SM grained sand, 25% medium grained sand, 45% fine grained I 14 4.5 110.7 I I sand 25"/o siltv fines. strom! brown. moist. @ I' ALLUVIUM: SIL TY SAND, approximately 30% medium grained sand, 50% fine grained sand, 20% silty fines, brown, damp. 5 17 6.4 109.2 I @ 5' becomes light red brown, trace clay. 20 9.2 111.0 I @7' SILTY SAND, approximately 20% medium grained sand, 60% fine grained sand, 20% sitly fines, light yellow brown, dry. 10 -~7 22 5.2 98.6 I SP @ 10' POORLY GRADED SAND, approximately 5% medium •.· grained sand, 90% fine grained sand, 5% silty fines, speckled black tan, damp. :> ·.· 15 25 for 5" 14.4 112.5 I •.· ML @ 15' SANDY SILT/SILTY SAND, approximately 20¾ medium SM grained sand, 30% fine grained sand, 50% silty fines, gray ·.• white, damp . . . • ·.· .. 20 128 for 5" 15.8 99.0 I ML @20' SANDY SILT, approximately 20% coarse grained sand, 80% siltv fines with trace clav. 11:rav white. damn. END OF BORING Fill 0-1' No groundwater No bedrock Boring backfilled with bentonite 25 PROJECT: Proposed Multi-Family Residential Project PROJECT NUMBER: 33090.1 CLIENT: Harding Street Neighbors, LP ELEVATION: NA DA TE DRILLED: July 8, 2014 LOR GEOTECHNICAL GROUP INC. EQUIPMENT: CME75 HOLE DIA: 8" I ENCLOSURE: B-3 ... .... Enclosure 10 r' .... TEST DATA [/) f--f--z f--[/) [/) lJ..l LI..l f--LI..l f-->-LI..l LI..l z f--z t:: "->->-0 LOG OF BORING B-4 w.. :J >-0 ~G::' f--0 [/) z f--0 c:: u~ LI..l -l u "-u 0 Ll.J ~ LI..l i__J -l 0 :c: [/) ~ f--c,::~ Cl ~ "-:c: "'. f--<( :J >-2 f--:J "-0 c:: f--c:: <( J LI..l -l 0 [/) Cl 0 ro ro 6 [/) <( -l 2 DESCRIPTION 0 ~ rec~ ~ PT (jj)0' SOD ~ --'----SM @0.5' TOPSOIL: SILTY SAND, approximately 10% coarse ~ SM grained sand, 30% medium grained sand, 35% fine grained I I ~ I sand 25% siltv fines. brown moist. 16 7.0 115.8 ~ @ 1' ALLUVIUM: SILTY SAND, approximately 30% medium ~ grained sand, 40% fine grained sand, 30% silty fines with trace clay, red brown, moist. 5 13 7.7 109.3 I @ 5' clay no longer present. 16 8.7 107.5 I @7' SILTY SAND, approximately 20% medium grained sand, 65% fine grained sand, 15% silty fines, red brown, dry. 10 .'--;'-;-23 6.7 98.5 I ·.· SP @ 10' POORLY GRADED SAND, approximately 10% medium grained sand, 85% fine grained sand, 5% silty fines, speckled black brown, dry, some pyrite flakes. ·.· ·.· ·.· ·.· ·.· 15 ~-;: 26 13.7 108.8 I :....: -= SW @ 15' WELL GRADED SAND, approximately 20% coarse ·=•~: ~.::.:.. grained sand, 30% medium grained sand, 45% silty fines, CL I tan. drv. I @ 16' LEAN CLAY with SAND, approximately 5% medium grained sand, 35% fine grained sand, 60% clayey fines of low plasticity, gray white, damp. 20 28 for 5" 21.1 106.6 I ML @ 20' SANDY SIL TY, approximately 5% medium grained sand, 35% fine grained sand, 60% silty fines with trace clay, gray I white damn. I END OF BORING Fill 0-1' No groundwater No bedrock 25 Boring backfilled with bentonite PROJECT: Proposed Multi-Family Residential Project PROJECT NUMBER: 33090.1 CLIENT: Harding Street Neighbors, LP ELEVATION: NA DATE DRILLED: July 8, 2014 LOR GEOTECHNICAL GROUP INC. EQUIPMENT: CME75 HOLE DIA: 8" I ENCLOSURE: B-4 ... ~ Enclosure 11