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Home My WebLink AboutTract 7352 Drainage StudyCity of Bakersfield, California r, Prepared by: PORTED c& ASSOCIATES, INC. Engineering and Surveying 1200 21St Street Bakersfield, CA 933111 i . ITRACT 7352 PURPOSE The purpose of this study is to develop a drainage plan that provides adequate drainage facilities for Tract 7352 and City Fire Station #13 and size the basin to accommodate the adjacent R-3 zoned property in accordance with City of Bakersfield Standards. Tract 7352 is 7.3 gross acres; the adjacent R-3 zoned property is 4.5 acres; and City Fire Station #13 is 2.2 acres. Tract 7352 consists of one sump lot and 26 approximately 7,200 square foot lots. It is bounded by Stine Road on the east, the Arvin -Edison Intake Canal on the north, Parcel A of Lot Line Adjustment No. 18-0390 Doc. No. 219037142 D.R. on the south, and the Dern Delta Farmer's Canal on the west. The site is located in the Northeast quarter of Section 27, Township 30 South, Range 27 East, Mount Diablo Base and Meridian. The site is proposed to drain to a basin in the southeast corner of the tract. Small shrubs and grass currently cover the entire site. The site is relatively flat. The soils onsite consist of Groups A and C hydrologic soil groups from the Dern County Hydrologic Soils Group Map. CALCULATIONS Initial times of concentration were based on Section 2.3.2.1 of the City of Bakersfield Subdividion and Engineering Design Manual. Street travel times were determined using the gutter flow chart attached with the hydrology calculations. Rainfall intensities were determined using the Time of Concentration - Intensity Chart for Bakersfield based on City of Bakersfield Engineering Department Standard D -I attached with the hydrology calculations. In accordance with the gutter flow chart attached with the hydrology calculations the Q that can be carried in a gutter with a 0.20% slope and a 6" water depth is 5.3 cfs. Inlet 2 has the largest 5 -year total flow of 3.78 cfs entering the inlet from two directions; therefore, the proposed 6" curb and gutter are adequate to handle the 5 year flow. All of the other gutters are adequate because they have less flow than gutters at Inlet 2. Hydraulic grade lines were calculated for each pipe reach as shown in the attached Hydraulic Grade Line Calculations. HGL control was established at the %2 water depth of the proposed drainage basin which is higher than the soffit of the last pipe reach. The HGL includes freeboard of a minimum of 0.5' at the catch basins and 1.5' for stubs to future parcels in accordance with City of Bakersfield Standards. Catch basins were sized in accordance with the attached nomograph for capacity of curb opening inlets. City Type "A" Catch Basin parameters were used to solve the nomograph. A copy of the nomograph is included in the Catch Basin Sizing Section. Standard 3.5' wide openings are adequate for all catch basins. The Christy U-32 inlet proposed in Area 5 to pick up the runoff from Stine Road was sized in accordance with the attached inlet grating discharge curve. Assuming 50% clogged, the flow that can be carried in the Christy U-32 inlet is 5.95 cfs. The largest 10 - year flow expected for the proposed inlet is 0.89 cfs (based on the Christy U-32 Inlet Area shown on the attached plan). Therefore, the proposed Christy U-32 inlet is adequate to handle the 10 -year flow. The drainage basin for this tract is in an area where subsurface soils are silty sands, sandy silts and sands. Soils Engineering Inc. determined the Coefficient of Penneability for soils lying within the basin areas. Results indicate that the drainage basin will drain within seven days (see attached calculations). SUMMARY A system of catch basins and pipes will carry runoff from Tract 7352 into an on-site drainage basin. CONCLUSIONS This study shows that adequate runoff drainage can be provided for Tract 7352 with the proposed drainage system and basin. IIVV�' '' f, FOR Porter & Associates, Inc. Calculations By: LKR Date: 03-10-2020 Job No. 2992C I ract tjbz Hydrology calculations Checked By: Date: Drainage Area I I Time of Concentration i I Qi i op I Pipeline Remarks Point of Acres I "G' CA !'CA RIG Gt T7 5 yr 5 yr 10 yr 10 yr I Frictionj Vp d I LT/P Conc. min. min. min. in/hr cis inthr cis Slope fps in ft min. i. @ Junction i4 ( i4 1= Junction J5 Junction J5 Sump RIG = Roof to Gutter Time i = Rainfall Intensity Vp = Velocity in Pipe L = Length of Pipe Reach GIT = Total Gutter Time Qi = Inlet Flow d = Pipe Diameter TIP = Pipe Travel Time TIT = Total time Qp = Pipe Flow Porter & Associates, Inc. Checked By: Calculations By: LKR Date: Date: 03-10-2020 Job No. 2992C I Tact 7352 Hydrology Calculations {matter Time for Catch Basins Point of Conc. Avg Street Slope (%) Vg fps Dist. ft GJT min. i1 0.25 1.2 238 3 i2 0.35 1.4 250 3 i3 0.70 2.0 185 2 i4 0.50 1.7 215 2 i5 0.20 1.1 360 6 STUB 1 NA 1.8 250 2 G/T = Total Gutter Time Vg = Gutter Velocity Porter & Associates, Inc. Checked By: Calculations By: LKR Date: Date: 03-10-2020 Job No. 2992C Area 2 I A (acres) C CA Fire Station 2.15 0.90 1.94 Lots 1.40 0.40 0.56 2: 3.55 2.49 Composite C: 0.70 DRAINAGE STUDY FOR TRACT 7352 HYDRAULIC GRADE LINE CALCULATIONS Porter & Associates, Inc. Checked By: Calculations By: LKR Date: Date: 03-10-2020 Job No. 2992C Tract 7352 Hydraulic Grade Line Calculations station length diameter area Q velocity friction exit friction entrance flowline freeboard ft in sf cfs ft/sec slope loss loss loss HGL elevation v z. Reach 1 32.2 18.0 1.767 5.51 3.12 0.0028 0.15 0.09 0.08 . r. Reach 2 41.4 18.0 1.767 4.54 2.57 0.0019 0.10 0.08 0.10 Reach 3 219.2 18.0 1.767 4.52 256 0.0019 0.02 0.41 0.05 Reach 4 154.6 18.0 1.767 4.52 2.56 0.0019 0.10 0.29 0.05 Reach 5 130.2 18.0 1.767 4.52 2.56 0.0019 0.10 0.24 0.05 _.::torr dxazn0aps yrs r €herstrzi taidi1L,t4 sf#t 7 Reach 6 24.0 18.0 1.767 1.26 0.71 0.0001 0.01 0.00 0.00 a1 � Reach 7 44.6 18.0 1.767 0.53 0.30 0.0000 0.00 0.00 0.00 '4 Reach 8 13.7 18.0 1.767 193 2.22 0.0014 0.08 0.02 0.04 f Reach 9 36.8 18.0 1.767 7.34 4.15 0.0049 0.27 0.18 0.13 ,.,; 10 a7ri�0 S�t2 Reach 10 10.0 18.0 1.767 6.52 3.69 0.0039 0.21 0.04 0.11 ... , ; Reach 11 40.0 18.0 1.767 0.89 0.50 0.0001 0.00 0.00 0,00 J = Junction Number i = Inlet Number 1. Pipe not flowing full. HGL=Soffit Porter & Associates, Inc. Checked By: Calculations By: KKR Date: Date: 03-10-2020 Job No. 2992C Tract 7352 Catch Basin Sizing Table Catch Basin Q - cfs Opening Required Opening Provided No. 10 - year ft. ft. 1 1.26 0.79 3.50 2 3.93 2.45 3.50 3 0.53 0.33 3.50 4 1.11 0.70 3.50 Notes: 1. Catch Basins are sized in accordance with the attached Inlet Capacity Chart for Type "A" Standard Catch Basin in a sag condition. CITY OF BAICERSFIEELD INLET CAPACITY N A SAG h = height of opening = 7" If = weer depth = 8" 1.0 .9 .B .r •E% 12 it 10 T5 10 8 4 0 Ij- CL 1.6 cfs/ft r r' 5 4 3 i. 6.5 46 u: l�ixP 1.0 « ,.13cC g WV °� � ►- W rrr�L'`� r w .4— X .4 z 4.5 4 O 0 2 0 .. r! 0 ul G. .r d .4 U. O x .1 W .O8 0 x 0 .06 .5 W t� ut I- � 0 .O4 2.5 .25 . 2 .03 0 Wx .{i2 .2 a. .1 5 a .01 .15 Kt CURB 1.5 ;a3 ;� �... ti rs HEIGHT LOCAL CEPA $SION { NOMOGRAPH FOR CAPACITY OF CURB OPENING INLETS. AT LOW POINTS a t.z I ca 0 (D N C13(UCL =3 cu ca En a) =3 - 7E c c:u3 —0 0- C: (D >1 CY) CD J-- 7C3 CU 0 :3 /.0M> a) &.« (D 22C c') > -M 0 0 cu cu a) (1) < /__a C14 a) > 4- (1) 0 $C: 0 yw2q® CU ft-- 0 n.« CL CU >U), 3 (1) - C) a) ca (D a) 0 MrkMr NT Ehginecring, F'HC hiCi. 209 836 s2i;;' Nam. 04 1999 132!4SAM Fr3 0 V 9 y MN) ...J 0 W DRAINAGE STUDY FOR TRACT 7352 DRAINAGE BASIN SIZING CALCULATIONS Porter & Associates, Inc. Checked By: Calculations By: LKR Date: Date: 03-10-2020 Job No. 2992C Tract 7352 Drainage Basin Design Volume Required Tributaries Area (Acres) C AxC Area 1 2.41 0.40 0.96 Area 2 3.55 0.70 2.50 Area 3 0.99 0.40 0.40 Area 4 2.06 0.40 0.82 Area 5 4.94 0.80 3.95 1 1395 CxA = 8.63 1 Design Volume = 0. 1 5*7-(CxA) = 1.29 AC -FT Porter & Associates, Inc. Checked By: _ Calculations By: LKR Date: _ Date: 03-10-2020 Job No. 2992C Tract 7352 Drainage Basin Volume Provided Average Accumulated Accumulated Elevation Area Area Volume Volume Volume ft sq. ft. sq. ft. cu. Ft. cu.ft. ac -ft 46.5 4157 4510 4510 4510 0.10 47.5 4864 5229 5229 9740 0.22 48.5 5595 5972 5972 15712 0.36 49.5 6350 6739 6739 22451 0.52 50.5 7128 7529 7529 29980 0.69 51.5 7931 8344 8344 38324 0.88 52.5 8757 9182 9182 47506 1.09 53.5 9607 10044 10044 57550 1.32 --� 54.5 10481 DRAINAGE STUDY FOR TRACT '7352 AND SOILS REPORTEXCERPT March 9, 2020 Old River Land Co. 10457 Van Horn Road Bakersfield, CA 93313 Attention: Mr. Kevin Antongiovanni Subject: Addendum No. 1: Drainage Basin Slope Stability Project: Vesting Tentative Tract 7352 Location: APN's: 538-010-07 & 538-010-35, Bakersfield, Kern County, CA Reference [1]: Geotechnical Investigation Report Project: Vesting Tentative Tract 7352 Location: APN's: 538-010-07 & 538-010-35, Bakersfield, Kern County, CA SEI File No. 19-17319, Dated, November 27, 2019 Dear Mr. Antongiovanni: Our scope of work consisted of performing an investigation for the proposed drainage basin for Tract 7352 to address the drainage and slope stability. FIELD INVESTIGATION Two [2] bores were drilled in the proposed basin area to a maximum depth of 41.5 feet below the existing ground surface. Borings were advanced using an eight (8.0) inch hollow -stem auger. Test data and descriptions from these holes form the basis of the conclusions and recommendations contained in this report. Undisturbed samples and disturbed bulk samples were obtained. Undisturbed, samples were taken using either a 2-30 (inside diameter) split -barrel sampler or a 1-3/8" (inside diameter), 2" (outside diameter) Standard Penetration Sampler (SPT). Penetration resistance of undisturbed soils was obtained by driving the above described sampler using a one -hundred -forty -pound hammer failing thirty inches (30"). Blow counts for each six inch'(6") driven increment was recorded and are reported on the Test Borings Logs. As drilling progressed, earth materials encountered were logged and classified in accordance with the Unified Soils Classification System and presented graphically on Logs of Test Borings, Figures 6 and 7. Approximate locations of test borings are shown on the Boring Location Map, Figure 1. LABORATORY TESTING Direct Shear and Permeability tests were performed on soil samples obtained during our field investigation. Standard Penetration Tests (SPT) were conducted during soil -sampling operations. Samples of earth -materials were taken at intervals varying from three (3) feet to 10 feet and were subjected to laboratory tests to evaluate basin drainage and slope stability. In-place density and moisture -content tests (ASTM D2216), permeability tests (ASTM D2434), and direct shear tests (ASTM D3080) were performed on samples selected as representative of the predominant earth materials below existing grade and below the invert of the basin. Test results are attached on the Laboratory Testing Summary, Table 1. 0 2020 SOILS ENGINEERING, INC. 4400?- AY Phone: 6618316100 infoosoilsenil BAKERSFIELD, CA 93313-2019 Fax: 6618312111 www.soilsenq: i SOILS ENGINEERING, INC. Old River Land Co. SEI File No. 19-17319 Project. Tract 7352 Drainage Basin Slope Stability March 09, 2020 Location: APN"s 538-010-07 & 538-010-35, Batters tell, A , Pae 2 C ---g Boring 5 & 6 were drilled to a maximum depth of forty-one and a half (41 %) feet below existing ground surface in the proposed basin area. Cohesionless sandy material were encountered at the invert level (see Table 1) consisting of silty sand and Poorly -Graded Sand, classified as SM and SP, respectively, in the Unified Soils Classification System (USCS). Based on our field investigation and our laboratory testing program, it is our engineering opinion that the majority of the sump areas can be expected to have highly permeable subsurface soils (See permeability test rates, -shown on the Laboratory Summary Table 1, attached) as shown on the boring logs, attached. Accordingly, the proposed sump shall drain in seven days or less. During the construction process, our field representative will review the construction process of the proposed sump. A letter will be issued stating compliance with these requirements when the construction of the sump is complete. WSQWWANM Slope stability for the subject site was assessed using the Price -Morgenstern method using the half - sign procedure and utilizing three different methods to search for the critical -failure surface: The Entry and Exit procedure assuming a circular failure -surface; the Grid -Centers and Radius method also employing a circular failure -surface; and the Block -Failure, or Non -Circular failure -surface method. Strength values were obtained from the results of Direct Shear tests, Figures C-2 and C-3, on saturated samples of earth materials obtained from the upper twelve feet below the existing ground surface. Slip -surfaces for the Entry and Exit, Grid and Radius, and Block -Failure methods are shown on the attached charts and calculations. These methods yielded safety -factors ranging from 1.540 to 1.543. We hope this provides the information you require. If you have any questions or need further assistance, please conta e. Respectfully SubmiSOMA SOILS ENGINES J No. 000125 L. Thomas Bayne, 117-EoA President FC Attachments: Boring Location Map, Figure I Logs of Botings, Figures 6 & 7 Laboratory Testing, Table I Sieve Analysis, Figures A-5 through A-7 Direct Shear, Figures C-2 & C-3 Slope Stability Charts & Calculations, (22 Pages) 0 2020 SOILS ENGINEERING, INC. 4400 YEAGER WAY Phone: 661831 610E BAKERSFIELD, CA 93313-2019 Fax: 66183121111 SOILS ENGINEERING, INC. Geotechnical investigation SEI File 19-17319 Vesting Tentative Tract 7352 November27, 2019 APNs: 5313-010-07 & 538-090-35 Bakersfield, CA Page 5 E. SUMP INVESTIGATION Baring 5 & 6 were drilled to a maximum depth of forty-one and a half (41'2) feet below existing ground surface in the proposed sump area. Cohesionless sandy material were encountered at the invert level (see Table 1) consisting of silty sand and Poorly -Graded Sand, classified as SM and SP, respectively, in the Unified Soils Classification System (USCS). Based on our field investigation and our laboratory testing program, it is our engineering opinion that the majority of the sump areas can be expected to have highly permeable subsurface soils (See permeability test rates, shown on the Laboratory Summary Table 1, attached) as shown on the boring logs, attached. Accordingly, the proposed sump shall drain in seven days or less. During the construction process, our field representative will review the construction process of the proposed sump. A letter will be issued stating compliance with these requirements when the construction of the sump is complete. G. SEISMIC DESIGN VALUES The seismic design values presented in the table below are based on the 2019 California Building Code (CBC). The Site Class for the proposed project was determined using standard penetration test data obtained at the site and are provided in the attached Boring Logs. The site is not located within an Alquist-Priolo (earthquake fault) Special Study Zone. The table on the following page 6 details the Seismic Design Criteria. 02019 SOILS ENGINEERING, INC. 'UQxg E E cs SOILS ENGINEERING, INC. 0 2020 SOILS ENGINEERING, INC. itt ui x to Di itl Z 0 0 CTu.z O's 0 Z 04 cli (0 ci cl) co ui > cs ci Z 0 :3 Z 0ti o o U o ci ci 6 00 V4 * co v 04 r, N cl) 0) t32m22m2fLcLfL(LEM2 2c 8 i" 0 ZD Z') ZD ZI) ?D &D 6 0 40 6 @ ro 6 @ 1 7 N T T 'T T c� 'UQxg E E cs SOILS ENGINEERING, INC. 0 2020 SOILS ENGINEERING, INC.