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HomeMy Public PortalAboutBUTLER AV_1705.pdfCI, COASTAL November 15, 2018 Civil Engineering Ms. Lisa L. Shaaf Planning and Zoning City of Tybee Island 403 Butler Avenue Tybee Island, GA 31328 Re: Tybee Beach Resort -1705 Butler Avenue — P.I.N. 4-0009-02-006 Dear Ms. Shaaf, Please find enclosed the following materials: 2 sets of plans entitled Beachview Resort and Spa, sheets C1-C3 dated 11/15/18. We have addressed the comments received from the City Staff as follows: Downer Davis —City Engineer 1) On the drainage calculations, markup of removed impervious areas & new impervious areas needs a little clarification. Clearer labeling and consistent heavier lines are what is needed. The pre and post calculations indicating no added runoff from the site is accepted. See revised drainage report. 2) The calculations indicate that runoff will be to the rear. Even if this is existing, runoff needs to be directed to R.O.W.'s and easements that give drainage outfall rights to this property. Absent of legal rights of drainage outfall (other than to Butler), with changed footprint of impervious areas and new construction, I have no basis to recommend runoff from this project onto the property of others. The drainage scheme now includes shallow swales to direct the water to small detention areas to assist in natural percolation onsite, with the flow oriented towards Butler Avenue instead of neighboring properties. The sidewalk design slopes south to property of others, indicating new runoff direction of flow onto property of others. This is not allowed. The cross slope of the sidewalk directs drainage to the r/w along Butler. 3) Drainage conveyance through channels (swales, gutters, pipes, etc...) need to be properly sized with adequate details on the plans. See attached calculations in drainage report. 4) There is no soil and erosion control design for this project. Proper best management practices for controlling sediment runoff from this site are required. Erosion control design has been added to depict best management practices. 5) If this site is considered a commercial site and not "residential", onsite maneuvering of vehicles is required. The current layout does not provide that. Parking layout approval will be deferred per discussion between the owner and George Shaw. 30011/2 River Drive . Thunderbolt, GA 31404 . Tel 912.232.9402 . Fax 912.232.9403 tomhavens cOCORa,talCiViLcom ■ coastalcivil.com 6) The design indicates that handicapped parking requirements are met on the prior project to the north. Supporting information is needed for that (number of total and handicapped spaces on the prior lot. At least an exhibit is needed to show the pathway on the adjacent site to handicapped spaces from the proposed sidewalk at the front of the building. (I believe it connects to parking spaces and not an adjacent pathway. Also, I the sidewalk shown in the R.O.W. at the front is routed through the van accessible aisle for the handicapped space on the lot to the north. I do not prefer this, but I defer to the City on this matter. Unless designed as ramps, slopes on handicapped pathways should not exceed 2%. Per Item 5. above this will be determined at a later date. If you have any comments or questions regarding the enclosed information, or require additional copies of the plans, please contact me at 912-232-9402 at your convenience. C 0 A S i A C s V I L ENGINEERING Hydrology Report For Tybee Beach Resort PIN 4-0009-02-006 1705Butler Avenue Tybee Island, GA Rev 11/15/18 '. '�,q• X9892 ��GFl�iQN�1l. Stork Drainage Narrative This project entails the remodeling/reconfiguration of an existing structure on Butler Avenue on Tybee Island and addition of three pervious parking spaces and sidewalk. The removal of existing impervious surfaces is approximately equal to the addition of new impervious surfaces, with the pre -project impervious area of 2,222 sf and post - project area of 2,210 sf. Due to this balance, the run-off volume generated by construction of the proposed improvements is unchanged from the current condition. The existing drainage pattern directs storm water overland from the Butler Street frontage westerly towards the southwest corner of the lot. The drainage pattern post construction will direct water easterly towards Butler Avenue, but it will be intercepted by small detention facilities before reaching the public right of way. The soils on the site are comprised of Chipley Urban land complex soils, as characterized by the NRCS website. The soils are good for hydraulic conductivity, and assumed that they are in Hydrologic Group A for the purpose of generating calculations for storm water quantities. These quantities have been indicated in the attached calculations, and 25 year storm values have been included in the site development drawings. I certify that these calculations and associated plans meet the requirements of the City of Tybee Storm Water Management Ordinance. 0' 20' 40' Graphic Scale 1"' = 20' EQUIPMENT USED: TOTAL STA71ON ANGULAR ERROR = 2" PER ADJU57ED BY OBSERVA770M PLAT CLOSURE = 1/30,000+ FIELD CLOSURE = 1/71,783 CONCRETE THIS AREA RESERVED FOR .-a- I CLERK OF SUPERIOR COURT waw I p xI q -'P•- LEGEND Q IRF IRON ROD FOUND � o I z v)'0 n O COMPUTED POINT s j N -OHP- OVERHEAD POWER LINES p S' z ¢ Y z WARD 5, BY BREWER LAND a O zr TELEPHONE PEDISTAL POWER POLE n:-izo 0 3 v a AC AIR CONDITIONER z i ,d:E x18.3 SPOT ELEVATION U a CONCRETE REF PAZ , NOR'(N LNC s'yvv NOW OR FORMERLY CLAIRE K. RITZLER PIN: 4-0009-02-005 1 I I x I zW I N 18'51'54" E 60.00' — — Tol IRF a ®AC c0 'URBEDx_ o o � ❑ `f` TWO STORY t !--•} AI OCK & o xl N FRAME10o fJ1RF.F dr 3r. M }�wo .-a- I o waw I p xI q -'P•- of 0 = N O >- �> o 3 REFERENCES Lo a 1. PLAT BOOK 7-P, PAGE 478. 3 w Lo 2. A TOPOGRAPHIC SURVEY OF LOT 5A, z ¢ Y z WARD 5, BY BREWER LAND a SURVEYING, DATED 3/14/2014 3. DEED BOOK 300 V, PAGE 269. 4. PLAT BOOK 48-P, PAGE 80 OLD REF PAZ , NOR'(N LNC s'yvv NOW OR FORMERLY CLAIRE K. RITZLER PIN: 4-0009-02-005 1 I I x I zW I N 18'51'54" E 60.00' — — Tol IRF a ®AC c0 'URBEDx_ o o � ❑ `f` TWO STORY t !--•} AI OCK & o xl N FRAME10o fJ1RF.F dr 3r. EL:8.91 �^ o I p xI q -'P•- 2nr. FLOOR F F. II 1 >- �> o EL 17.41 w w N n l Y r` Z p� o JZo rCQOp W W �i Om'I x Z o I. L rn n .� o 01 Y a w x 0 5. SUBDIVISION MAP BOOK 30-S, PAGE 95. CP w A z IRF 1 9' o' Dh1 UR: I�'_ — —59.93'L — �IRF__A— 6.0.02' 119.95- N 18'49 42° E ',a S 18'49'1 ' 'n It BENCHMARK NAIL SET EL.: 9.88 \ (NAND BS) :OHP P 0 'o 0 THIS SURVEY IS A RETRACEMENT OF AN EXISTING " EDGE OF PARCEL OF LAND AND DOES NOT SUBDIVIDE OR 'o CREATE A NFW PARCFL. THE RECORDING ASPHALT .� N INFORMATION OF THE DOCUMENT(S), MAP(S), PLAT(S) OR OTHER INSTRUMENT(S) WHICH CREATED THE PARCEL(S) ARE STATED HEREON. RECORDATION OF THIS SURVEY DOES NOT IMPLY APPROVAL OF THE LOCAL JURISDICTION, AVAILABILITY OF PERMITS, COMPLIANCE WITH LOCAL REGULATIONS OR REQUIREMENTS, NOR SUITABILITY FOR ANY USE OR PURPOSE OF THE LAND. FURTHER, THE UNDERSIGNED LAND SURVEYOR CERTIFIES THAT THIS MAP, PLAT, OR PLAN COMPLIES WITH THE MINIMUM TECHNICAL STANDARDS FOR PROPERTY SURVEYS IN GEORGIA AS SET FORTH IN CHAPTER 180-7 OF THE RULES OF THE GEORGIA BOARD OF REGISTRATION FOR PROFESSIONAL ENGINEERS AND LAND SURVEYORS AND AS SET FORTH IN THE GEORGIA PLAT ACT OCGA 15-6-67. /1 ._'*l ..a BUTLER AVENUE 80'. RIGHT OF WAY TAX ASSESSORS PROPERTY IDENTIFICATION NUMBER: 4-0009-02-006 CURRENT ZONING. C-1 TOTAL LOT AREA: 0.125 ACRES STREET ADDRESS.• 1705 BUTLER AVENUE SURVEY NOTES: zz W E z w90 1. THE ELEVATIONS SHOWN ARE BASED ON NAVD 88 DATUM. 2. COORDINATES AND DIRECTIONS ARE BASED ON GEORGIA STATE PLANE COORDINATE SYSTEM (NAD83), EAST ZONE. 3. ACCORDING TO F.I.R.M. MAP NO. 13051CO326F, REVISED SEPTEMBER 26, 2008, THE PROPERTY SHOWN ON THIS SURVEY LIES IN ZONE AE(BFE 13). 4. ONLY ABOVEGROUND, READILY VISIBLE STRUCTURES AND UTILITIES WERE LOCATED FOR THIS SURVEY. THIS SURVEYOR MAKES NO WARRANTY OR GUARANTEE AS TO THE LOCATION, EXISTENCE, OR NON-EXISTENCE OF ANY BELOWGROUND, NON-VISIBLE UTILITIES OR STRUCTURES. su m o A SURVEY Or t B R E W E R EASTERN PORTION OF LOT 7, WARD S CITY OF TYBEE ISLAND. CHATHAM COUNTY. GEORGIA LAND SURVEYING P.O. Box 441 N — -- - — ---' --- __f _ Poolcr,GA31322 V w Phone(912)856 PREPAREDFOR craig(u:brewersurvey.rnm -2205 N FRANK KELLY www.BreecrrSurvcy.com M1' V V O 1! Pa JI 2 w ols".1 81 RE DI 9 11 > r4 Q0 FINISHED CRADF Dom- Y] 1) APP—M MUNMM t1EV TpX M —E PAVING Ow9E ss. 6 VDN fi ON —E — -- -- DAM —2012. 24' F oo",� 00 z PRIM TO ADUDINf FCC CURB CL i �1� 11KL X <01 ,N: --9-- Ell HEADER CURB j.LM�54* E IRF NO SCALE < NDW DR FO MERI.Y DNES 1. IR„a M Ammw .1— R.O. _44 JrI —PV ? Ld :L. �AT Dw, 9 B N S), 17 .sae I u &Mow"-, /*j z < 451-2 !FJ:7 is je— -7 ev= UTILITIES PR'.TECTION CENTER L.D.R. xOw OR FORIERLY A aumom 4LT, (WT KMAIA I— —Qr ARD) 1-cs W HARPER 11Z PERVIOUS PAVERS � -14 NO SCALE 0 U) �Tl 0 E- cl DRcl -Lms- z E- 4 DUNK. RT c. z ols".1 81 RE DI 9 11 > r4 Q0 forts:,IF Dom- Y] 1) APP—M MUNMM t1EV TpX M —E Ow9E ss. 6 VDN fi ON —E — -- -- DAM —2012. z PRIM TO ADUDINf BEUNDER �D M UNM SR— eMOM =. = OR APPROVED Ell Ld < B HIMARK K. - V11:1 DT FAMRW ? Ld :L. z z 9 B N S), 17 BUTLER AVENUE BO' RIGHT OF WAY u 0 cia 0 /*j z < 451-2 !FJ:7 is je— -7 ev= UTILITIES PR'.TECTION CENTER cl DRcl Hydrograph Plot Hydraflow Hydrographs by Intelisolve Friday, Jan 19 2018, 10:22 AM Hyd. No. 1 Tybee Beach Reso rt -P re -p roject Hydrograph type = SCS Runoff Peak discharge = 0.607 cfs Storm frequency = 25 yrs Time interval = 1 min Drainage area = 0.124 ac Curve number = 69 Basin Slope = 0.0% Hydraulic length = Oft Tc method = TR55 Time of cone. (Tc) = 3.30 min Total precip. = 8.00 in Distribution = Type III Storm duration = 24 hrs Shape factor = 300 Hydrograph Volume = 1,972 tuft TybeeBeachResort-Pre-project Q (cfs) Hyd. No. 1 -- 25 Yr Q (cfs) 1.00 - — 1.00 0.90 - -- — — 0.90 I ' - 0.80 — - - - 0.80 0.70 — - 0.70 i 0.60 - j j — 0.60 i 0.50 -i r— 0.50 0.40 -- - — 0.40 0.30 - -- — --- 0.30 0.20 - - ! -- — -i 0.20 0.10 -- — 0.10 000 000 0 2 5 7 9 12 14 16 19 21 23 26 Hyd No. 1 Time (hrs) Y Hydrograph Plot Hydraflow Hydrographs by Intelisolve Hyd. No. 2 Tybee Beach Resort -Post -p roject Hydrograph type = SCS Runoff Storm frequency = 25 yrs Drainage area = 0.124 ac Basin Slope = 0.0% Tc method = TR55 Total precip. = 8.00 in Storm duration = 24 hrs Friday, Oct 19 2018, 8:8 AM Peak discharge = 0.607 cfs Time interval = 1 min Curve number = 69 Hydraulic length = Oft Time of cone. (Tc) = 3.30 min Distribution = Type III Shape factor = 300 Hydrograph Volume = 1,972 cult TybeelBeachResort-Post-project Q (cfs) Hyd. No. 2 -- 25 Yr Q (cfs) 1.00 �— - - —� 1.00 0.90 - — 0.90 i 0.80 — ! - — - 0.80 0.70 0.70 j I 0.60 1—--�- —�- -; ;- - - - - 0.60 I I I I 0.50- - I r -� � - i 0.50 I I 0.40 -1 - -�- — 0.40 i 0.30 r - -}— r -- - - { 0.30 I I I I 0.20 h - - - -- - - �— i - -�— — I 0.20 0.10-- - - -- h - - -- 0.10 0.00 - -- — - i 0.00 0 2 5 7 9 12 14 16 19 21 23 26 Hyd No. 2 Time (hrs) r EL=8.1,0 'JUIN' OR 170F;MEl'-U ", 'HAIRLES J. WILKINS JR P \NILKINS "IN: 4-0009-0,2-0030 MATCOH EUVA110N OF EXISTIN" NEVER CURB lF. Fa. ALONG 11S] I 0 10, 70 Xi: FG- 10.S0 Z"I CONCRETE'. 'T., TWO ORY BE REMOVED & Fl SLAA FJr, 8" HPDE UNDERORWN QYP 7b' JCIIAQ SEE 00 U:17 41 :1 - � C � 1-)." L ('I,:) _ 00 -'R v-, DETAIL, DING Cl <Al:'Ei\i HAL. -Y KEU.- '�r GIMDE 7 0 AG, MWERPROOF BUILDN" -TEM WALL' 4'x4' DOWNSPOUT WEL.I--- RC'HI7'E.Cl"URlLSEE PUINS 'TYP EE DETAII..., '43 C 1 RAIN CHAIN/00ONSPOU7 FL --7.190 0: Q 'LEVAIUDN OF MAMI-I E. I-:XIS3T ING HEADER CURD DOWNSPOUT I" -LONG R. OR SWALE PERCOtxnot4 SEECl 4 F -G= 10.40 DETAIL, M�G , Channel Report Hydraflow Express by Intelisolve Area A Swale Q (cfs) Triangular Area (sgft) Side Slope (z:1) = 6.00 Total Depth (ft) = 0.50 Invert Elev (ft) = 100.00 Slope (%) = 0.40 N -Value = 0.035 Calculations Compute by: Known Q Known Q (cfs) = 0.15 Elev (ft) 101.00 — 100.75 Section _ t i 100.50 - - -- 100.25 ---...- -- - i 100.00 -+- - - - 99.75 -- -- -- — 0 1 2 3 4 5 6 Thursday, Nov 15 2018,12:5 PM Highlighted Depth (ft) = 0.21 Q (cfs) = 0.150 Area (sgft) = 0.26 Velocity (ft/s) = 0.57 Wetted Perim (ft) = 2.55 Crit Depth, Yc (ft) = 0.14 Top Width (ft) = 2.52 EGL (ft) = 0.21 Reach (ft) i 7 Depth (ft) 1.00 0.75 0.50 -- 0.25 mennoffly1ril I 1 -0.25 8 Channel Report Hydraflow Express by Intelisolve Area B Swale Triangular = 0.29 Side Slope (z:1) = 6.00 Total Depth (ft) = 0.50 Invert Elev (ft) = 100.00 Slope (%) = 0.25 N -Value = 0.035 Calculations Compute by: Known Q Known Q (cfs) = 0.27 Thursday, Nov 15 2018, 12:8 PM Highlighted Depth (ft) = 0.29 Q (cfs) = 0.270 Area (sqft) = 0.50 Velocity (ft/s) = 0.54 Wetted Perim (ft) = 3.53 Crit Depth, Yc (ft) = 0.17 Top Width (ft) = 3.48 EGL (ft) = 0.29 Elev (ft) Section 101.00 -�---- -- �- —� —�- 100.75 ! I I 100.50 - • i — -� ---r rt 100.25 100.00 ---r - T---- 99.75 --- - — - ^f 0 1 2 3 4 5 Reach (ft) Depth (ft) 1.00 0.75 0.50 -- 0.25 0.00 6 7 -0.25 8 1 Table 2.1.5-1 Runoff Curve Numbers Cover description Cover type and Average percent hydrologic condition impervious area Cultivated land: without conservation treatment with conservation treatment Pasture or range land: poor condition good condition Meadow: good condition Wood or forest land: thin stand, poor cover good cover 3 Open,space (lawns, parks, golf courses, cemeteries, etc.) Poor condition (grass cover <50%) Fair condition (grass cover 50% to 75%) Good condition (grass cover > 75%) Impervious areas: Paved parking lots, roofs, driveways, etc. (excluding right-of-way) Streets and roads: Paved; curbs and storm drains (excluding right-of-way) Paved; open ditches (including right-of-way) Gravel (including right-of-way) Dirt (including right-of-way) Urban districts: Commercial and business 85% Industrial 72% Residential districts by average lot size: 1/8 acre or less (town houses) 65% 1/4 acre 38% 1/3 acre 30% 1/2 acre 25% 1 acre 20% 2 acres 12% Developing urban areas and Newly graded areas (pervious areas only, no vegetation) 1 Average runoff condition, and'la = 0.2S Curve numbers for hydrologic soil groups A B C D 72 81 88 91 62 71 78 81 68 79 86 89 39 61 74 80 30 58 71 78 45 66 77 83 25 55 70 77 68 al. 86 89 49 69 79 84 39 61 74 80 98 98 98 98 98 98 98 98 83 89 92 93 76 85 89 91 72 / 82 87 89 89 92 94 95 81 88 91 93 77- 85 90 92 61 75 83 87 57 72 81 86 54 70 80 85 51 68 79 84 46 65 77 82 77 86 91 94 2 The average percent impervious area shown was used to develop the composite CNs. Other assumptions are as follows: impervious areas are directly connected to the drainage system, impervious areas have a CN of 98, and pervious areas are considered equivalent to open space in good hydrologic condition. If the impervious area is not connected, the SCS method has an adjustment to reduce the effect. 3 CNs shown are equivalent to those of pasture. Composite CNs may be computed for other combinations of open space cover type. 2.1.22 Georgia Stormwater Management Manual Volume 2 (Technical Handbook) i„ 31° 59'27'N Hydrologic Soil Group—Bryan and Chatham Counties, Georgia 0 514050 514070 514080 fi {I, i •;� }'L{'h+ L11s+1. '•'f ..k]" � 'r .i.� 1 r•1- '— y� jib.. f� ��� yam: y�iC �.� ■■ I .� I. ... I�•• - 'T� '��,. r •cif. � .,:�• �`. .,r - 31° 59' 24" N 514060 514070 514060 514090 514100 514110 514120 514130 514140 514150 514160 514170 514180 514190 5142M 514210 514220 514210 3 k Map Scale: 1:828 f printed on A landscape (11" x 8.5") deet NMeters n0 10 20 40 60 /V 0 40 80 160 240 Map projection: Web Mercator Comer coordinates: WGS84 Edge tics: UiM Zone 17N WGS84 31° 59'27" N r o i 31° 59' 24' N 3 F` Natural Resources Web Soil Survey 1/19/2018 f i Conservation Service National Cooperative Soil Survey Page 1 of 4 Hydrologic Soil Group ---Bryan and Chatham Counties, Georgia Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI Cue Chipley-Urban land A 3.5 complex Totals for Area of Interest 3.5 Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long -duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff. None Specified Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 100.0%, 100.0% 1/19/2018 Page 3 of 4 u www.SAG1S.orq Map Viewer INDEX INTERMEDIATE SUPPLEMENTARY DEPRESSION Parcels Outline sfiG!S MAKES NOwARRAN".REPRES— ORGUARANT ASTOTHECONTeNT.SEOUENCE. w. 00.0 0.08 0.16 1 Miles 2;6 450 Feet www.SAGIS. Savannah Area Geographic Information System (SAG Sources Esu, HERE. D.L.I—. USGS. lat—M tuINCREMENT P. NaZan, Earl Japar METI, ESb China (Hong Kong), E.ri Korea, E,ri (Thailand), Manyindia, NGCC, ol,p and the GIS US_ Community Page I, SAVANNAH, GEORG 1 A IC -03-11951 •._ http://www.chathamcounty.org/Chatham/Engrg_images/Appendix_G_resized.jpg 8/4/2t