Loading...
3.6.18 - Evaluation Letter Footing Drains.pdfLovell-Sauerland and Associates, Inc. 19217 36th Avenue West, Suite 106 Phone: 425-775-1591 Lynnwood, Washington 98036 LSAEngineering.com Engineers Surveyors Planners Development Consultants March 6, 2018 City of Edmonds Engineering Division LSA No. 5537 1215 h Avenue N Edmonds, WA 98020 Re: Brackett's Court, 21276 - 80'h Avenue W. (Building Permit #20160598) fo, ie__ 0 .6 2 018 Engineering Site Plan Construction Evaluation Letter DEVELOPMENT SERVICES COUNTER Per Mr. Jake Lyon's request, LSA is pleased to provide the following professional engineering evaluation of the proposed stormwater drainage system for the Brackett's Court 14-lot Plat at 21276 - 80'h Avenue W. The engineering drainage and site development plan included the installation of footing drain, which will discharge into City's storm drainage system at the southwest comer of 801h Avenue W/212 1h Street SW intersection. During the course of construction activity, crawl space/footing drain for individual building (except Buildings # 5 and #8) were tightlined together with downspout drain, and discharging into designated infiltration trenches, which were sized for collected runoff from building roof and pavement. Per the "Footing Drain" (attached) prepared by Liu & Associates, Inc., dated September 25, 2017, the amount of water in footing drains will be limited, and that it will be acceptable to discharge footing drain water into infiltration trenches. Refer to the attached drainage as -built plan and drainage analysis, crawl space elevations are set above overflow elevations, stonnwater in the drainage systems will not backup to flood building's crawl spaces. If you have fiii-ther questions or need additional information, please give me a call. Sincerely, John W. Yuen, P.E. Project Engineer W. ks/ 35420 Gis, NAL (0 LIU & ASSOCIATES, INC. Geotechnical Engineering Engineering Geology Earth Science September 25, 2017 Mr. Randy Brockway Pride Ventures 320 Dayton Street, Suite 108 Edmonds, WA 98020 Dear Mr. Brockway: Subject: Footing Drain Brackett's Comer 80th Avenue W and 212th Street SW Edmonds, Washington L&A Job No. 15-058 You propose to dispose water in townhome building footing drains into infiltration trenches. It is our opinion that the amount of water in footing drains will be limited and that it will be acceptable to discharge footing drain water into infiltration trenches. Yours very truly, LIU & ASSOCIATES, INC. J. S. (Julian) Liu, Ph.D., P.E. Principal 19213 Kenlake Place NE - Kenmore, Washington 98028 Phone (425) 483-9134 - Fax (425) 486-2746 CONCRETE SIDEWALK VEFMAL CUFM 12" CAST IRON WATER MAIN EX. Cl 17,4','lx4' C C7U MH I TSE U7 ME El MONUMEN 1+ 00 212th STREET S.W. 2+0( (T,B M. 'A" III LX SSCO INV SE)=443 80-6"D.:: va-As", tl—\ 6' SEW I P GAS MAIN NV�NE)�443.41-9-D. a _ _ — IM SAMIArtY 17 k. �9L 10 20' 0 0 42% OF OF Or OF OF OF OF OF W OF OF OF OF Of ----------- .......... ........... W-) ,4. 4'PW 3v W-6 ?v .01 -o N114- W-4m BUILDING 14 cor-I INV(N)-4.61-�PVC (0 F.) INV(S)-4�-�PVC 1114- 1-1p. .1 ;F-,xww larl INV(Q-313-4'PVC ��10) V(N)-�43-PVC (0 F.) -o N .48' E_I..., - BUILDING 13 0 BUILDING 12 BUILDING 11 . .50 g3)-444.I32-4'- (". W-3.54' C�-138-4-PYC 1 :0 NWN)-441-e- tr-t., CPO < a_ V--a? :NV(E):� -8'PVC NV(S) --6-PVC ... . .... .......... ------ ------------- . ............. sscoo 201+00 jjj!� 0 Or OF + CO) cr-413 (PER PLAN) 5. R 4. 4� 7 95 BUILDING 8 R-1 15 INV(SE)-"4. -7-6-P- (W) V )_ �44.45-4�-PVC (OF) INV(Q-35-4 PVC INV(S)--l.-4'Plc 3 INV(Q-4�2 -4-PVC IS L BUILDING 10 BUILDING 9 SSCO PvC :NV(( )=-.- PARKING vb Ed . . ........ . r ... . . ......... Ed > BU ILDING 7 2Y .m". CLUE RI -7.40 smo W-Q 73' Do 4Y NV -4'PVO V�11-4 E)�-.- 'PVC NV(N)— 85-4'PVC N, =-1. -�N)-446 -4-PVC (D F) 447.19 co CD 5R-4'PVC BUILDING 6 Z BUILDING 5 RIM-7- (o F.) 12 Of %-am 2V < I. -A. El- rk.) 44 4103-40M .................... A-- 0. + Go - ............ - - ----- .... . .. ---------- IFF-4-2 (SUNW-) "-..z2k Y RI -11. cl� < S-0,45, BUILDING 4 NV(W)=�,fig-'PVC (0 F.) N -Pw 111-41111." M"114-VIVI 4�3 1-'ftll F N&A" INV(E)-443�-4'PVC ..L-epw -w BUI L ING 3 c� X RI ­D4 NE)-4 D P NZ) (0E) N V( .v(E)-- -4'PVC BUILDIN LLJ+ BUILDING 1 ............ . r.w EX. GARAGE (APPROXIMATE) Drainage Analysis (Downspout, Crawl Space, and Connection Point as -built information were received via emails dated December 20 from the Chris Lyon, and February 8 from Jake Lyon) Footing drain invert elevations are assumed to be at the same elevation as crawl space drain. Lot I Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #1 Invert Bottom of Rock Elevation at Trench #1 Top of Rock Elevation at Trench #2 Invert Bottom of Rock Elevation at Trench #2 Top of Rock Elevation at Trench #3 Invert Bottom of Rock Elevation at Trench #3 CB #2 (Per plan) Rim = 447.4+/- Inv In 443.70 (S&W) Inv Out = 443.70—(E) To Trench #1 Inv Out = 445.20—(N) O.F. 448.30 (Surveyed) 446.10 445.30 445.30 v' 444.30 To CB #2 445.20 (Per Plan) 443.70 (Per Plan) 439.20 (Per Plan) 444.50 (Per Plan) 443.00 (Per Plan) 438.50 (Per Plan) 444.60 (Per Plan) 443.10 (Per Plan) 438.60 (Per Plan) CB #2 (Surveyed) Rim = 446.94 Inv In 444.07-4" PVC (S) Inv Out = 443.96-4" PVC (E) Inv Out = 445.08-4" PVC (N) In order to achieve the designed 100% infiltration, a Tee section (with bottom capped) shall be attached to the outlet of the overflow pipe (invert @ 445.08), the top of the Tee section shall be extended to overflow water surface elevation @ 445.20. Section of 4" PVC has been added to connect CB #3 and Infiltration Trench #3, both Infiltration Trench #2 and Infiltration Trench #3 are hydraulically connected. Overflow would occur out of CB #4, and ultimately discharge into City's drainage system — an existing CB located at southwest corner of 80"' Avenue W/212 th Street SW Intersection. CB #3 (Per plan) Rim = 447.76 Inv In = 443.00(S) Inv Out 443.00 (E) To Trench #2 CB #4 (Per plan) Rim = 447.14 Inv In 443.10(S) Inv Out = 443.10 (E) To Trench #3 Inv Out = 444.60 (W) O.F. CB #3 (Surveyed) Rim = 446.59 Inv In 443.24-4" PVC (S) Inv Out = 443.14-4" PVC (E) Inv Out = 443.14-4" PVC (W) CB #4 (Surveyed) Rim = 447.19 Inv In 443.61-4" PVC (S) Inv Out = 443.26-4" PVC (E) Inv Out = 444.69-6" PVC (W) Downspout, crawl space and footing drains are tightlined together, and connected to CB #2 @ 444.07, collected stormwater will enter the infiltration trench (#1) @ 443.96. When water level reaches above 445.20 (adjusted) @ CB #2, stormwater will enter the overflow pipe, which is connected to CB #1. Stormwater will enter the infiltration trench (#2) @ 443.14. The Contractor had hydraulically connected the two infiltration trenches (#2 & #3) @ CB #3, the overflow would occur out of CB #4 @ 444.69, and ultimately discharge into City's drainage system — an existing CB located at southwest corner of 80th Avenue W/212 th Street SW Intersection Crawl space elevation (445.30) is 0. 10' above the overflow elevation 445.20 (adjusted) @ CB #2. Stormwater in the system will not back up to flood the crawl space. Lot 2 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #2 Invert Bottom of Rock Elevation at Trench #2 Top of Rock Elevation at Trench #3 Invert Bottom of Rock Elevation at Trench #3 CB #3 (Per plan) Rim = 447.76 Inv In = 443.00(S) Inv Out 443.00 (E) To Trench #2 CB #4 (Per plan) Rim = 447.14 Inv In 443.10(S) Inv Out = 443.10 (E) To Trench #3 Inv Out = 444.60 (W) O.F. 448.0 (Per Plan) 446.10 445.30 445.30-' 444.50 To CB #3 444.50 (Per Plan),/ 443.00 (Per Plan) 438.50 (Per Plan) 444.60 (Per Plan) 443.10 (Per Plan) 438.60 (Per Plan) CB #3 (Surveyed) Rim = 446.59 Inv In 443.24-4" PVC (S) Inv Out = 443.14-4" PVC (E) Inv Out = 443.14-4" PVC (W) CB #4 (Surveyed) Rim = 447.19 Inv In 443.61-4" PVC (S) Inv Out = 443.26-4" PVC (E) Inv Out = 444.69-6" PVC (W) Downspout, crawl space and footing drains are tightlined together, and connected to CB #3 @ 443.24, collected stormwater will enter the infiltration trench (#2) @ 443.14. The Contractor had hydraulically connected the two infiltration trenches (#2 & #3) @ CB #3, the overflow would occur out of CB #4 @ 444.69, and ultimately discharge into City's drainage system - an existing CB located at southwest corner of 80 'h Avenue W/212 th Street SW Intersection. Crawl space elevation (445.30) is 0.61' above the overflow elevation (444-69) @ CB #4. Stormwater in the system will not back up to flood the crawl space. Lot 3 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #3 Invert Bottom of Rock Elevation at Trench #3 CB #4 (Per plan) Rim = 447.14 Inv In 443.10(S) Inv Out = 443.10 (E) To Trench #3 Inv Out = 444.60 (W) O.F. 447.5 (Per Plan) 446.10 445.30 445.30 444.00 To CB #4 444.60 (Per Plan) 443.10 (Per Plan) 438.60 (Per Plan) CB #4 (Surveyed) Rim = 447.19 Inv In 443.61-4" PVC (S) Inv Out = 443.26-4" PVC (E) Inv Out = 444.69-6" PVC (W) Downspout, crawl space and footing drains are tightlined together, and connected to CB #4 @ 443.61, collected stormwater will enter the infiltration trench (#3) @ 443.26. The overflow would occur out of CB #4 @ 444.69, and ultimately discharge into City's th drainage system — an existing CB located at southwest corner of 80't' Avenue W/212 Street SW Intersection. Crawl space elevation (445.30) is 0.61' above the overflow elevation (444.69). Stormwater in the system will not back up to flood the crawl space. Lot 4 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #4 Invert Bottom of Rock Elevation at Trench #4 CB #5 (Per plan) Rim = 447.44 Inv In = 443.40(S) Inv Out = 443.40 (W) To Trench #4 Inv Out = 444.90 (E) O.F. 447.8 (Per Plan) 446.10 445.30 445.30 \1` 444.00 To CB #5 444.90 (Per Plan) 443.40 (Per Plan) 438.90 (Per Plan) CB #5 (Surveyed) Rim = 447.19 Inv In 444.15-4" PVC (S) Inv Out = 443.56-4" PVC (W) Inv Out = 444.69-6" PVC (E) In order to achieve the designed 100% infiltration, a Tee section (with bottom capped) shall be attached to the outlet of the overflow pipe (invert @ 444.69), the top of the Tee section shall be extended to overflow water surface elevation @ 444.90. Downspout, crawl space and footing drains are tightlined together, and connected to C13 #5 @ 444.15, collected stormwater will enter the infiltration trench (#4) @ 443.56. The overflow would occur out of CB #5 @ 444.90, and ultimately discharge into City's 1h drainage system — an existing CB located at southwest corner of 80"' Avenue W/212 Street SW Intersection. Crawl space elevation (445.30) is 0.40' above the overflow elevation 444.90 (adjusted) @ CB #5. Stormwater in the system will not back up to flood the crawl space. Lot 5 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation (Downspout) Connection Point Elevation (Crawl Space & Footing Drains) Top of Rock Elevation at Trench #5 Invert Bottom of Rock Elevation at Trench #5 CB #6 (Per plan) Rim = 447.2+/- Inv In 444.75 (W) Inv Out = 444.75 (E) To Trench #5 Inv Out = 446.25 (N) O.F. 447.9 (Per Plan) 446.30 445.50/ 445.50 445.00 To CB #6 445.00 To Overflow 446.25 (Per Plan) 444.75 (Per Plan) 439.00 (Per Plan) CB #6 (Surveyed) Rim = 447.18 Inv In 444.88-4" PVC (W) Inv Out = 444.58-4" PVC (E) Inv Out = 446.24-4" PVC (N) Crawl space and footing drains are separated from downspout drain. Both crawl space and footing drains are tightlined together, and connected to the overflow system in between lots #5 and #8 @ 444.72. Crawl space and footing drains elevation (445.50) is 0.50' above the connection point elevation (445.00). Stormwater in the system will not back up to flood the crawl space. Lot 6 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #7 Invert Bottom of Rock Elevation at Trench #7 CB #8 (Per plan) Rim = 448.05 Inv In = 443.90 (E) Inv In = 443.90 (W) Inv Out 443.90 (N) To Trench #7 447.7 (Per Plan) 446.10 445.30 445.30 445.00 To CB #8 445.40'�Per Plan) 443.90-"(Per Plan) 441.40 (Per Plan) CB #8 (Surveyed) Rim = 447.40 Inv In = 444.85-4" PVC (E) Inv In = 444.85-4" PVC (W) Inv Out 443.85-4" PVC (N) Downspout, crawl space and footing drains are tightlined together, and connected to CB #8 @ 444.85, collected stormwater will enter the infiltration trench (#7) @ 443.85. The overflow would occur out of CB #9 @ 445.00 (adjusted), and ultimately discharge into City's drainage system — an existing CB located at southwest corner of 80th Avenue W/212 th Street SW Intersection. Crawl Space and Footing Drain elevation (445.30) is 0.30' above the overflow elevation 445.00 (adjusted) @ CB #9. Stormwater in the system will not back up to flood the crawl space. 1a.5-4 Lot 7 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #7 Invert Bottom of Rock Elevation at Trench #7 CB #8 (Per plan) Rim = 448.05 Inv In = 443.90 (E) Inv In = 443.90 (W) Inv Out 443.90 (N) To Trench #7 447.7 (Per Plan) 446.00 445.30 445.30 445.00 To CB #7 445.40 (Per Plan) 443 ' 90'(Per Plan) 441.40 (Per Plan) CB #8 (Surveyed) Rim = 447.40 Inv In = 444.85-4" PVC (E) Inv In = 444.85-4" PVC (W) Inv Out 443.85-4" PVC (N) Downspout, crawl space and footing drains are tightlined together, and connected to CB #8 @ 444.85, collected stormwater will enter the infiltration trench (#7) @ 443.85. The overflow would occur out of CB #9 @ 445.00 (adjusted), and ultimately discharge into City's drainage system — an existing CB located at southwest corner of 80th Avenue W/212 th Street SW Intersection. Crawl Space and Footing Drain elevation (445.30) is 0.85' above the overflow elevation 445.00 (adjusted) @ CB #9. Stormwater in the system will not back up to flood the crawl space. +�/ r.�/ I/ () L.-,J ANKC-01 Ground Floor Elevation 448.0 (Per Plan) Downspout Elevation 446.30 Crawl Space Elevation 445.50 Footing Drain Invert Elevation 445.50 Connection Point Elevation (Downspout) 444.50 To CB #10 Connection Point Elevation (Crawl Space & Footing Drains) 444.50 To Overflow Top of Rock Elevation at Trench #8 Invert Bottom of Rock Elevation at Trench #8 CB #10 (Per plan) Rim = 447.2+/- Inv In 444.75 (W) Inv Out = 444.75 (E) To Trench #8 Inv Out = 446.25 (S) O.F. 446.25 (Per Plan) 444.75 (Per Plan) 439.00 (Per Plan) CB #10 (Surveyed) Rim = 447.54 Inv In 444.95-4" PVC (W) Inv Out = 444.53-4" PVC (E) Inv Out = 446.24-4" PVC (S) Crawl space and footing drains are separated from downspout drain. Both crawl space and footing drains are tightlined together, and connected to the overflow system in between lots #8 and #9 @ 444.41. Crawl space and footing drains elevation (445.50) is 1.00' above the connection point elevation (444.50). Stormwater in the system will not back up to flood the crawl space. Lot 9 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #7 Invert Bottom of Rock Elevation at Trench #7 448.5 (Per Plan) 446.80 445.91 445.91 444.82 To CB #9 445.40 (Per Plan) 443.90 (Per Plan) 441.40 (Per Plan) CB #9 (Per plan) CB #9 (Surveyed) Rim = 447.85 Rim = 447.95 Inv In 443.90 (E) Inv In 444.35-4" PVC (E) Inv Out = 443.90 (S) To Trench #7 Inv Out = 444.05-4" PVC (S) Inv Out = 445.40 (W) O.F. Inv Out = 444.45-4" PVC (W) In order to achieve maximum infiltration , a Tee section (with bottom capped) shall be attached to the outlet of the overflow pipe (invert @ 444.45), the top of the Tee section shall be extended to elevation @ 445.00. Downspout, crawl space and footing drains are tightlined together, and connected to CB #9 @ 444.35, collected stormwater will enter the infiltration trench (#7) @ 444.05. The overflow would occur out of CB #9 @ 445.00 (adjusted), and ultimately discharge into City's drainage system — an existing CB located at southwest corner of 80th Avenue W/212 th Street SW Intersection. Crawl space elevation (445.91) is 0.91'above the overflow elevation 445.00 (adjusted). Stormwater in the system will not back up to flood the crawl space. Lot 10 Ground Floor Elevation 447.7 (Per Plan) Downspout Elevation 446.50 Crawl Space Elevation 445.20 Footing Drain Invert Elevation 445.20 Connection Point Elevation 444.30 To CB #13 Top of Rock Elevation at Trench #11 444.80 (Per Plan) Invert 443.30 (Per Plan) Bottom of Rock Elevation at Trench #11 439.80 (Per Plan) CB #13 (Per plan) Rim = 447.6+/- Inv In 443.30(S) Inv Out = 443.30 (E) To Trench #11 Inv Out = 444.80 (S) O.F. CB #13 (Surveyed) Rim = 447.15 Inv In 443.30-4" PVC (S) Inv Out = 443.23-4" PVC (E) Inv Out = 444.67-6" PVC(SE) In order to achieve the designed 100% infiltration, a Tee section (with bottom capped) shall be attached to the outlet of the overflow pipe (invert @ 444.67), the top of the Tee section shall be extended to overflow water surface elevation @ 444.80. Downspout, crawl space and footing drains are tightlined together, and connected to CB #13 @ 443.30, collected stormwater will enter the infiltration trench (#11) @ 443.23. The overflow would occur out of CB #13 @ 444.80 (adjusted), and ultimately discharge into CiVs drainage system - an existing CEI located at southwest corner of 80th Avenue W/212t Street SW Intersection. Crawl space elevation (445.20) is 0.40' above the overflow elevation 444.80 (adjusted). Stormwater in the system will not back up to flood the crawl space. Lot 11 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #12 Invert Bottom of Rock Elevation at Trench #12 CB #14 (Per plan) Rim = 447.5+/- Inv In 444.10(S) Inv Out = 444.10 (E) To Trench #12 Inv Out = 445.60 (N) O.F. 448.3 (Per Plan) 445.20 445.00 445.00 444.50 To CB #14 445.60 (Per Plan) 444.10 (Per Plan) 439.60 (Per Plan) J CB #14 (Surveyed) Rim = 447.33 Inv In 444.44-4" PVC (S) Inv Out = 444.31-4" PVC (E) Inv Out = 444.43-4" PVC (N) In order to achieve maximum infiltration, a Tee section (with bottom capped) shall be attached to the outlet of the overflow pipe (invert @ 444.43), the top of the Tee section shall be extended to elevation @ 444.75. Downspout, crawl space and footing drains are tightlined together, and connected to CB #14 @ 444.44, collected stormwater will enter the infiltration trench (#12) @ 444.31. The overflow would occur out of CB #14 @ 444.75 (adjusted), and ultimately discharge into CiVs drainage system - an existing CEI located at southwest corner of 80th Avenue W/212t Street SW Intersection. Crawl space elevation (445.00) is 0.25' above the overflow elevation 444.75 (adjusted). Stormwater in the system will not back up to flood the crawl space. Lot 12 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #13 Invert Bottom of Rock Elevation at Trench #13 CB #15 (Per plan) Rim = 447.5+/- Inv In 444.35(S) Inv Out = 444.35 (E) To Trench #13 Inv Out = 445.85 (N) O.F. 448.7 (Per Plan) 446.20 445.40 445.40 444.20 To CB #15 445.85'(Per Plan) 444 * 35-(Per Plan) 439.60 (Per Plan) CB #15 (Surveyed) Rim = 447.35 Inv In 444.45-4" PVC (S) Inv Out = 444.36-4" PVC (E) Inv Out = 444.61-4" PVC (N) In order to achieve maximum infiltration, a Tee section (with bottom capped) shall be attached to the outlet of the overflow pipe (invert @ 444.61), the top of the Tee section shall be extended to elevation @ 445.15. Downspout, crawl space and footing drains are tightlined together, and connected to CB #15 @ 444.45, collected stormwater will enter the infiltration trench (#13) @ 444.36. The overflow would OCCUr out of CB #15 @ 445.15 (adjusted), and ultimately discharge into CiVs drainage system - an existing CB located at southwest corner of 80th Avenue W/212t Street SW Intersection. Crawl space elevation (445.40) is 0.25' above the overflow elevation 445.15 (adjusted). Stormwater in the system will not back up to flood the crawl space. Lot 13 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #14 Invert Bottom of Rock Elevation at Trench #14 448.0 (Per Plan) 446.20 445.40 445.40 445.00 To CB #16 445.85 (Per Plan) 444.35 (Per Plan) 439.60 (Per Plan) CB #16 (Per plan) CB #16 (Surveyed) Rim = 447.9+/- Rim = 447.77 Inv In 444.35(S) Inv In 444.27-4" PVC (S) Inv Out = 444.35 (E) To Trench #14 Inv Out = 444.30-4" PVC (E) Inv Out = 445.85 (N) O.F. Inv Out = 444.79-4" PVC (N) In order to achieve maximum infiltration, a Tee section (with bottom capped) shall be attached to the outlet of the overflow pipe (invert @ 444.79), the top of the Tee section shall be extended to elevation @ 445.15. Downspout, crawl space and footing drains are tightlined together, and connected to CB #16 @ 444.27, collected stormwater will enter the infiltration trench (#14) @ 444.30. The overflow would occur out of CB #16 @ 445.15 (adjusted), and ultimately discharge into CiVs drainage system — an existing CEI located at southwest corner of 80th Avenue W/212t Street SW Intersection. Crawl space elevation (445.40) is 0.25' above the overflow elevation 445.15 (adjusted). Stormwater in the system will not back up to flood the crawl space. Lot 14 Ground Floor Elevation Downspout Elevation Crawl Space Elevation Footing Drain Invert Elevation Connection Point Elevation Top of Rock Elevation at Trench #15 Invert Bottom of Rock Elevation at Trench #15 CB #17 (Per plan) Rim = 447.8+/- Inv In 444.35(S) Inv Out = 444.35 (E) To Trench #15 Inv Out = 445.85 (N) O.F. 447.7 (Per Plan) 446.50 445.20 445.20 445.20 To CB #17 445.85 (Per Plan) 444.35 (Per Plan) 439.60 (Per Plan) CB #17 (Surveyed) Rim = 447.80 Inv In 444.47-4" PVC (S) Inv Out = 444.48-4" PVC (E) Inv Out = 444.92-4" PVC (N) Downspout, crawl space and footing drains are tightlined together, and connected to CB #17 @ 444.47, collected stormwater will enter the infiltration trench (#15) @ 444.48. The overflow would occur out of CB #17 @ 444.92, and ultimately discharge into City's drainage system — an existing CB located at southwest corner of 80th Avenue W/212 th Street SW Intersection. Crawl space elevation (445.20) is 0.28' above the overflow elevation 444.92. Stormwater in the system will not back up to flood the crawl space.