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Item 4EAGENDA ITEM #4E JANUARY 9, 2006 CITY OF ATLANTIC BEACH ~. CITY COMMISSION MEETING STAFF REPORT AGENDA ITEM: Follow-up to City Commission action denying a request for a Waiver from Section 24-66 of the Land Development Regulations requiring ~, On-Site Retention for a lot located at 1718 Selva Marina Drive. SUBMITTED BY: Rick Carper, P.E., Public Works Director ~. Sonya Doerr, AICP, Community Development Director DATE: December 30, 2005 BACKGROUND: On November 28, 2005, the Commission took action to deny a request for a Waiver from the Land Development Regulations related °~ Section 24-66(b), which requires on-site storage of stormwater runoff such that there is no increase in the rate or volume of flow to off-site, for a property at 1718 Selva Marina Drive. Since that action, the property owner, Joseph Fitzgerald, has advised Staff that it was not his intention to go forward with the waiver request ~' at that time and stated that he had not been notified that the request had been scheduled for consideration by the Commission. Mr. Fitzgerald, however, had been in discussions with both Planning and Public Works Staff regarding available Commission agenda dates and had submitted a written waiver request in Octoberforthe purpose of being heard by the Commission. (See attached chronology.) ~. While Staff's recommendation related to this matter remains unchanged, Mr. Fitzgerald, upon written request to the City, may submit a new or an'~ended, waiver request ifi he chooses to do so. Unlike Rezonings, Zoning Variances and Use-by-Exceptions, there is no 365-day time limit to re-apply following a denial. RECOMMENDATION: As previously provided, Staff continues to recommend disapproval of the waiver request. LDR Section 24-66(b) gives the Director of Public Works authority to waive on-site retention "if storage is determined to be unnecessary or unattainable". In this case, Staff feels it is both necessary and attainable, and that to grant the waiver would set a dangerous precedent for the City. ATTACHMENTS: Chronology of requested Waiver and supporting information from November 14th and 28th City Commission meetings. BUDGET: No budget issues. REVIEWED BY CITY MANAGER: ,~ January 09, 2006 regular meeting ,. AGENDA ITEM #4E JANUARY 9, 2006 Chronology - 1718 Selva Marina Drive -Public Works Department (All dates 2005} May 5 -Plans received by Building Department. May 10 -Routed to Public Works. (AS400) May 12 -Public Works comments with example On-site Retention calculation form faxed to Gamel Construction. Discussed comments with Mr. Gamel by phone. May 16 to May 27 -Met several times with Frank Gamel to discuss various options for retention. May 27 -Approved Gamel proposal for on-site retention. Excluded rear half of property from calculations because it drains directly to Selva lagoon. May 31 -Building Permit issued. (AS400) October 05 -Initial discussions about waiver request with Sonya. October 26 -Began drafting staff report recommending disapproval of waiver request.; discovered City copy of drainage plan /retention calculations missing. October 28 -Visited construction site - no copy of plan available on site. October 31 -- Phone conversation with Frank Gamel -Discussed that Mr. Fitzgerald was requesting waiver, was not aware of that. He does not have copy °~ of approved plan. November 7 -Staff report submitted to City Manager. November 14-Initial Commission consideration of request. Not acted upon because staff not sure applicant contacted. November 28 -- Commission denied waiver request after staff reported a letter had been sent to applicant (sent to wrong address). December 14 -met with Mr. Fitzgerald and Frank Gamel to discuss On-Site Retention requirement. Copies of Staff Report and Commission minutes '~ provided to Mr. Fitzgerald. (Appointment was for 3pm, showed up at 1:10; I let him know meeting would be abbreviated due to weekly meeting with City Manager). ~. AGENDA ITEM #4E JANUARY 9, 2006 Norembe:r 24. '?00~ R.CGUI,AR CGt!•€:YISSIt)I`41~IEETiN(i Pa c la 14loton. Ant~oint Carole ~'~zney to fill tEze vacancy otz thc~ Free Conservation. Board. 1VI4ved by W'otfson, seconded 6,v Sammons Commissioner Waters asked that the appiicatnns lae included to the agenda packets rr~lien aetinn is scheduled tc~ be taken. Voters Ayes 5 - Iiorno, Fletcher, Sirr~mans, 'Waters, '4'Volfsan lways NI[?TIQN CARR~I) Action nn Re:snlutians 6, Action on Resolutions None. . tA.ctian on Qrdinances ~. Action on Ordinances ,,,, Nome. Miscellaneous .business S. Miscellaneous BusNness ~. Request to replat a portion of Block 1 within Unit I. of the Setva Marina subdivision, including ail of Lot 33 and portions of Lot 3~ and Lot 3~t for the. purpose of creating three single family resadetrtlal lots ranging in size i'ranl S1C7 square -feet to 12;881 square feet in Lot Area. This property is located at the northwest corner of I2th StreeE anal Seiva N1a.rina Circle {City Ilfianagery This item ~sras acted or, earlier 7:tCe meeting, W ~ B. Bequest for a ~~aiver from..Land Developrnet-t. Regulations 0 itequirernent for Un-Site Retentaan for a loz located at 1718 Z Selva ~vlarina Drive {Cit}~ Manager) City 141anager l ianson noted that this item ryas addressed at the pr~evi©us Cvtnmssion meeting and that the staff report ryas included: in the saenda packet along with ~1r. Carpet's recc~rnmendatic~n fnr dertia;l c-t the request. Rick Carper, i3~•ecror of Public Works,. added that stmt did not .receive any ~• response :from the applicant. lWlaftons Uenv the. request for a ~~'uiver fcnrn Land DeveloArnent ,.. lte ulatxnns re uirement for on-site retention for a lot located at 17I$ Seiva 4~Tarina Drive, ~. - - ----•.,,...._... _._.__. _ _ AGENDA ITEM #4E JANUARY 9, 2006 .. N~yenzber 28.2(1gS RFGLII ~R ~"f~'~IMI~SfiC}"~ ib1EETING Page I Commissioner Waters painted out staff's error in their calculations pertaining to .the owner's application and the need to treat all. properties uniformly in respect to stormwater retention requi~~men€s. :~~~oved by Simmons, seconded 1~y 13©rnt~ Fates: .~,ye: 5 -13arno, l~letcher, Si.ITlrtI0ll8j 'IVaters, Wolfson 7N~ ay~r.~ 0('~ tVif31'TIJ~~ CARRIED C. Request far a'Vt'aiver From the Laird. Develvpnient Regtitati+ons to exceed the 50~d Trnpervaus Surface Area. limit -vithin the ~'" Selva Linkside 1'UD for a lot located at 1538 Lnkside Drive, i<torth (City Manager} Iocated_at 1538 I.,inl.side Drive. Moved by Simmons, seconded by Borno ,~ commissioner Waters disagreed with sti~~immin pools being considered as a pervious surface and indicated that this was cont~a~:y to the perspective of the Saint Johns 12iver Water I~~anage~nent District. 1~1e believed that water ,~, from this property will run into anoeher person's yard or into the street and.. stated that he would not appro<<e this request... Charles Labassi, 1538 Linkside Drive, ntt~odticed himself as the applicant ~. and acknowledged that he exceeded. the impervious surface area lirnit. He provided some background information an his neighborhood and his involvement in the Linkside Homca~vne~-'s Association. I-Ie discussed the .results and effects of the storm4vater runoff from. his propertw. Rick. Carper, Director of Public Worlcs, dispila}Fed a pliQta cif the lot and the Coaxtmissianers discussed the perniealailty and sut~face area of the applicant's deck, swimming pool, and pavers on the pt~perty and. their effect on surrounding areas. Mayor `4'dlfsan camn~ented that Atlantic Bezich his a very lenient impervious surface area requrerner~t compared with that. of other cities and ~" spoke against granting the waiver. The question was called and. a tall call vote. was- taken fay City Clerk Bussey. ~. ~. AGENDA ITEM #4E JANUARY 9, 2006 ADENbA ITE:\1 #t3U YQV~MBER 1J 2rr0~ Ct~`1C C3F l~Tt,AN'TtC 81~C~ CITY C~DiftllMtSStC?N tlll~~"Ct~tC STAFF R~R4RT AGEI~DA,1TEMt. Request for a Waiver from Land aeveloprnent Regulations Requirement for C}n- Site Retention far a lot located at 1718 Seiva. Marina t3rive SUt3ttA1TTBD BY: Rick Carper, P.E., Public Works Qirector BATE: October 26, 2005 BACKGROt1Nl~, Land ©evelopment Regulations {LDR) Section 2~-66(b) regwires-cn- sitestorage of s#orrnwater r~txnoff asuch that there is no increase in tt~e .rate or volume of flow to off-site,. from e-~ery c~evetoped ar redeveloped iRarcel" {emphasis added}. The property owner is regtaesting a wvaiverfrvm on-site retention requirements by saying the LDR show not tae applied to a new home within an already existing subdivision, stating the regulation "applies only to subdivisions and not to individual tots". As noted, Section 24-fi~i{b) specifically aRPlies to-both development and redevelopment at .the Parcel {lot) level. Although the Selva Marina Subdivision is nearfiy taunt: out, the lot in question was undeveloped at the tune of the permit request. The intent of LaR Section. 2466(b~ is to ensure the, capacity of existing stormwater caliectian systems is not exceeded because of the increase in starmwater runoff caused by the increased impervious areas. resulting from both deaetopment {riew construction) and from redevelopment {tear downs}, That the property ~s being built to Less than 5~0°fa impervious simply means it is complying with another section of the City's LDR {Section 24-10~ {f~~, unrelated to on-site retentian. Public Wortts approved the Building permit request far property at ~" 17'1 ~ Selva Marina Dave on May 27, 2005.. At that time, Public iNarics had ocanducted several plan reviews with the Builder {Garrrel CQnsrucon} to obtain a plan :fear on-site. retention that me# the spurt of the City's Lend Development Regulations, Because the lot has natural Type B dreina+ge {splits front and ream, Staff agreed that the portion of the .:tat draining directly to the. lagoon would mat be ~" considered in the retentian calculations. The front half of the lot drains to Salvo Marina. Glrive, with an existing City catch basin at the curls. This curb inlet is piped. directly tta Selva Lagoon: slang Mr. l=itzgerald's northern property tine. Combined with flaw from the inlets _immediatety across Selva Marine t3rive, this 18" pipe carries nrnoff from approximately 7'fl0 linear feet of salvo Marina Drive, aver g0t} `""~ AGENDA ITEM #4E ' JANUARY 9, 2006 :~ GENDA TTEiI~I #$D '~ N(1y~I4iIiII2 Lit, 24}05 '~" ~ feet of Live Qak Lane and 5011 feet of the north side of Palmwood Drive and a[t the properties ad~a4~nt to these roads. ~"' As a resuCt 4~f an AdmCnistrative oversight, Staff is unabCe to find the permitted drainage pCan and approved on-site retention calcuta#iorts #or this property. Staff requested a cxypy Pram the Builder who stated ~"' he did not have them either. However, the portion of the Cat draining directCy to the lagoon was taCcen Cato a4;count when. the amount of on- sit4a storage required was calcuCated. ~• RE~t"~CVIMC?t~aA~T1UN: Staff recommends disapprove! of the waiver request. LDR Sectlan 24-f~6{by gives the Dire4:tor of PuCalc V~tortcs authority ter waive on-sine retention "if storag4a is determined to h+e unnec4~ssary or *~ unattainableR. !n this cesa, Staff feels it is b4ath necessary and attainatal4a, and that to grant the waiver would set a dangerous precedent for the City. ATTACHC4l~NTS: 1,)11V2~irrer Request from Joseph Fitzgerald, 1'l'!8 Selva Marina Drive ~. ~} DgAC3 Land DeveCoprnent regulations, Section 2466 3} Rer~uired retention volume cal4auCation worCcsheet 4) Sits !Tart --1718 Selva CVCarCna Drive BUl3GET: No C3udget issues.. REVIEWED BY CITY MANAQ:-~. ,~. .., ~ __ ,~ ,............._ ,.,., . _ ........ ...... AGENDA ITEM #4E JANUARY 9, 2006 Cite of Atlantic Beach City Cortirnssion 14~1et~ting AGENDA. ITE1~T #bD N4VEI4~1.8IR I~t, ?00 Agenda Itextx: Ite~quest far a waiver for yproperty (171 S4iva l~tarina Dr.} regarding Regulation ~- Atlantic beach Zoning, Subdivision and Land l7eveloptnent "" Regulations, Sections 24-fxfi(b). Present Situstons Upon applying for a building permit. for to}r tterv hc~rne, lv1r. Rick '~" Carper, P,E. Public t~t~orks Director used section ?4.66(b) of the abo~,e regulation. to eAleulate the volume of rur- o`f and storage requirements fctr my ittdividuai lot at 1718 Selva Marina Dr. The results .from the calculation. required 3,70 cu. ft. of storage. After ~* discussion with my builder, h~It•. Frank Garnel, Mr. Carper reduced the requrcrnent to 2,500 cu. t't. between the lYause and tl~e road (see attached sheet f1}. Ltpon additional. discussion with Mr. Garnel, he agreed to a ~" birm to be constructed in the front of tlZe propertiy t:~a retain. the wvater. Then tlke building permit 1z~~as approved. 'Waiver Requests I reciuest thafi the Regulation of Atlantic Beach, Sttbdi<<~isiori and ~„ Land I?evelopment, Section ?~-66(b) trot be applied to my property on 1718 ~el~~a Marina Dr. Reasons: I do not believe that an itydiviclual: lot, within an established community should be required. to comply with a regulation that has as its intent to cover a Subdivision and Land Ueti~elopment sttuattan. Selva Mztrin~ was developed in ttto 1960's and constructed the water management system for the subdivision far all the homes at that time. if the present Chinkitag of the requirement for' a 2S year and 24 hour rainfall (9.3 inches) hay changed since then., applying this regulation to the two remaining prt~pertie on the street,. which do not have homes on them, {2 homes out of ~t0 - 5~"G) ~~~ould have a "~" smolt impact an the water management situation. Certainly, ttton~ v~~ouid not be enough impact to correct the situation if the system is now defined to be unable to handle the situation in its present condition. ~*" I don't believe the regrtiution is being applied to hotmes tvl~ich are being rebuilt car under going renovations. ' Reasonings The last 40 feet. of my property is located in the canal which is used as the ~~~ater management system for the subdi~fision. Therefore, t 6 ~c of the total. gropea•ty is beirag used for the system presently. (150 ft.. X 250 ft. = 37,500 sa. f't. ~ 40 ft. X 1S0 ft. = 6000 sq. ft.) Also, ort the North Bast. corner of the lat., which is in the street, there is a storm water drain which collects the. water in to a buried 3 ft. comtgated steel. pipe draining under the property .into the canal in the rear of the home. I feel teat I am ~„ already contributing to the water tnanagemant of the cotnnutnity. Reasoning (ec~n#.}. 't`ine front of the property (home to property line is '75 ft X 15f1 ft.~ is i l,ZSO sq. ft. if the initial calculation of a storage requirement (3,70 cu. ft.} were to ,.. r ~.. .. AGENDA ITEM #4E JANUARY 9, 2006 AGENDA. I'T'EM #3i~ N~VEiVt:I3~12 24, 2t?fJ5 ** ~ apply and the depth were l2 ft. then t~vo thirds of the front yard would be a holding pond. Also; I followed the regulation regarding the tree retention regulations and to follow this water retention approach the trees in the holding pond area would be affected n~eaatively. .. ` Summary. Tlz~ existing regulation, (section 2.4-E-b b} applies: only to subdivisions .and nor to individual lots.. ~. Uur building plans and specs do not in any war violate tije mpen~ious surface area limit of ~0 which was established in N©vernber of2001. Tn addition, the last ~D feet of our lot is in the canal, part. of the ~„ exisrinb storm water management system. Therefore care atreadv have a storm water management s}rstetn on our lot, The fact that Mt•. Carper reduced Glee requii°etnent indicates that. he also believes that the resulting calculation is too much fqr an individual lot. Mr. Frank Gomel, my construction manager, and an active builder for tine Iasi. 25 }rears at the beaches, has also indicated that he has never seen this kind of approach to att. i.n:dividual lot. ,.~ ' Section ~_4-~G(d) permits the cornmissian to authorize limited waivers on a case by case basis, frc~rn specific provisions of the land developttient regulations when itts demonstrated that compliance with such provision would be '~ unreasonable, in cottfli.ct with. the public interest, or a practical impossibilt}r. Regards., 7oseph Fitzgerald ~.. w. ~. ~, ___ ~a ~. e,. ~ "'~ n!. ~~ ', 1~ a" ? O ~~~ ~_ """~ AGENDA ITEM #4E JANUARY 9, 2006 AGENDA ITEitif #FD I~C7'b'Eh~IBER 1~, 2U05 ,, ., _ 1 ,,'` . ~~ .~' t `°~, ,~' ~` ~,, ;, ~, "" S~:Iva Marina thrive _ . .~. .~. .a.._.,~rc,.,.~_ -__-------- .,.- -- ----. _ ~j, 3 , pm1.44gtdu5 /~ G'~IYE M~J~Y ! __._ ._.. .. ~_._ _ ~ FITLGE 2J~LD R~SIL7 N rv _.. ._._.~ _ i _, °~ ~ .. r 3= ~GE ! ~.T~r~.wzR ~ ' ~ ~ I~ ~ I~ kae- ~~.. r~~ i .~•~+~«~~~~ ""~ 1 R4~id Mi S ~ T3 I I ~©t 5, Slcck 9 - 5elva i~ar~na Unit 5 1 RriR Rf0'YT M JL:R CC1R ~Cd14yCT MG rRtGlCIM 1 ~ c'~T~'~P:'~~ ~ ~ ~^~e~•. EfSU:iUiL. JJ~ ElECPFGt110fi5 ^ vE4~T 4~t ~/ ~~ f I m Da.,~, M.LR_u 6, 706E A CO ~ ~WI D,flA1'ti;~e g&3GI^t. CIOtCl~e . . R T4 ~±eeusvee+wa. wT OacrRVet'aAa waea #e aCtipeea~ i FgtiM "!5 FdliG'TiLL_31rY1. i t R~ AGENDA ITEM #4E JANUARY 9, 2006 a~ ~L 0 ~. ~L C r r ~ ~~ w...~.~~av~Yi~~,;. ,~,~, ;;. d 'L ca c '~ ca d r ti r ~~ O ~ }+ U ~ ~ . -- ~ ~. ~ L. ~ ~ ~ V Q O ~, ._ ~ ~ p ~ ~ ~ ~ .- ~ .. O to ~ ~ .- ~ ~ 4~ ~ L D L 0 ._ .~.^r ~ '~ s ._ ~ ..~, ~ ~ ~ ~ v Q ~ ~ ~ ~ d f+ .. N 0 3 0 0 a~ >° 0 a~ L of 0 L O O ~O ..~..J CCU ~ - ~ U C~ -- R3 U 4~ -~ V ~ ~ ~ ~ ~ .a ~ ~ •- -F-~ -~-+ > ~ a~ ~ ~ U ~ O L ~ AGENDA ITEM #4E JANUARY 9, 2006 ^ U c~ ._ O U CCU -~ Cn 0 ~. AGENDA ITEM #4E JANUARY 9, 2006 ~,GIrNb~'~ ITEIi #3U N4VEIIBER IBS. ?00 Sec. 24»66. Starmwater, Drainage, Storage arud Treatment ~.equirements. (Emphasis added) •^ (a) Tapographt~~ azad Grading. All Lacs and Development sites skull b+e constructed: and graded. .n such a manner sa that the starmwater drains to the adjacent Street.. an existin natural element used to convey starm~~~ater {See section 22-30, definitions; Starmwater Nlanagennent System), ar a City drainage structure after meeting on-site storage requirements, as listed within this Section. The City shall be provided with. a pre-construction topographical surrey prior to the issuance of a Develppment Permit ,,, and cost-constructitfn topographical survey prior to the issuance of a Certificate of Qecupanc}~#. Said surveyrs shall be prepared by a licensed. Florida surveyor, and the requirement far either ar both surveys may be waived 13y tho Director of Public Works if determined to be unnecessary. {b) do-Site Storage: 'I'ho A4pplicant shall ba required to prax~ide an-site stora~a, such that there is na increase in: the crate or vvluzne of flav-~ to off~site, frgm e~erF~ ~. developed ur redeveloped Parcel, and provide documentations and calculations to demonstrate compliance. Development. Projects previously permitted by the 5t. Johns River `Water Management District. (SJR~'MD), which have an in-compliance ~"" retention ar detention system that collects and controls run-off, are exempt. The requirement far an-site storage may be `~+raived l,y the Director of Public Waz-ks if storage is deterrrtined to be unnecessary ar unattainable. '" Valurne calculations far .Cats that require an-site stara;ge should, be based. on the difference iza run-off valuine generated by the ne~~~ impervious. area ("delta valurne" and waxlld be calculated by: ~" ~'=C.~R.~12. ~vh~re 'tl` = volume of storage in cubic feet, A = area of the tat in square feed '"' R = 2~ year. and 24 hour rainfall depth (9.3 inches) aver the lot area, and C =run-off coefficient, which is 0.6 for the 5a%a .maximum imperviousness, 0.4 .far 25% imperviousness, and Q.2 for 0~°!~ imperviousness. This delta volume (past V minus pre V in cut?c Feet) mint be .stored at least l fiat above the wet season water table. and below the overflow paint to off-site (in many cases this may be the adjacent road elegy+ation}. As an option, and. as approved by the ~. Director of Puiblic, V~orks, the owner of the parcel to be devela~ed or redeveloped may implemexit, at the applicant's cast,. off-site storage and necessary conveyance to control existing flood stages off-site. (c) Plaad Plain Storage: There shall. be na net. lass of storage far areas in me 10{}-year #iaadplain, whore a tlaodplain elevation has been. defined by either the Federal.. ~„ Emergency Management Ageucy {FEMA) on Flood insurance Rate flaps (FiRMs), the. 1995 Stormwater Master Plan, the Core City project, ar the 20x2 Stonnwater htTaster .Plan Update (e,g., Hopkins Creek). Site grading shall. create storage an-site to ~„ mitigate far :filling of volume on-site. This storage is in addirion to the storage required far the increase in impervious Surface Area. ~.. ~.• AGENDA ITEM #4E JANUARY 9, 2006 AGENI3A ITE~4~1 #SU h'OVEI4IBER 1~, 2fl05 (d) ~tarm~vater Treatment: 5tarmwater treatment shall be provided far a volume equivalent to either xetentian ar detention ti;pith filtration, of the run-off from the first one (I}inch of rainfall.; ar as an option, far facilities with a drainage area of less than one hundred (1{}a} acres, the first one-half (.1...12} ir~Gh ofrun-off pwrsuant to Chapter t2~2~, Florida Administrative Cade (FAC). ?Ja discharge from an}' stormwater facility shall cause or contribute to a violation of water quality standards as provided in Section 62.342 of the Florida. Administrative Cade. This treatment volume can be included as part. of the on-site storage requirement in item d (?) of this Section. (e~ IJPDES Requirements: All. canstructian activities shall. be in confaznaance with the City's National Pollutant. Discharge Elimination Systems (NPDES) permit, in addition to the requirements of the Water Management District. anti the Florida Department of Environmental Protection.. NP1}ES requirancnts include use of Best Management. Practices {B14~IPs} prior to discharge rota natural or artificial drainage systems. Beginning 141ay k~ 20Q~, all construction projects. of one acre ar mare t~;~ill e. require a'sVPDES permit. (f) Enfarcernent: Subsequent to approval of a property ownerxs final grading, including. ~"' on-site andlar fl~oad plain. storage and stormw ater treatment, the imprt~vements shall be maintained key the property owner. Failure to maintain the mproveEx-ents will squire restaratian upon notihcatian ~y~ the Directax of i'ublic 'Works, within a '"" stipulated time fran7:e, If restoration is not timel}r completed, the City shall have the right to complete the restararian, and the City's actual. cast incurred, tagethcr with a. charge of lOCI°./o of said casts to caner the City's administrative expenses, skull be "' charged to the owner. ~. 0 ..._ ....... ... ........ ........~.. AGENDA ITEM #4E JANUARY 9, 2006 AGENDA ITi~~'f #SD ~. NQ~'EA~IBER I4, 200 Runoff ~'alurne Calculations (Ref City of .A,tlantic Beach Zoning, Subdission and Land Der~elopeut Regulatioas, Section 24-fi6(b}: 17J$ Sel~~a NEarina Drive ~'oluxue calculations far lots that require on-site storage should be based on the difference ut rua- aff volume ~eneratedb} the neww~ impervious area t"delta volume") axtd would: be calculated: by: 'V=C~hIt~'12,. w~there tr = wrolumc of storage in cubic feet. A =areas of the lot in square feet, ~e» R = 25 ;tear and 24 hour rainfall depth ('~ 3 inches} oYer the tot.. area, and ~ C =run-off coefficient~ which is tl.b for rite SO% rnaxunum impervious coverage, U.4 for ^S°fa impervious coverage, and Q.2 for fl% imgerw!ioua coverage. Tltis delta volume (post V minus pre V in cubic feet} must.. b~e stored at least l foot above the u~t ~, season wvater table and bdlaw the overflow point to off site {in man}•~ cases this tna}~ be die adjacent road elevation}. As an option, and as approved by the Director of Public Works, the owner of the parcel to be dew~elvped: or t~eveloped may implement, at the applicant's cost, off-site storage and necessary C©ttVCyAIICe t0 C©ntrol extSUll~ flQOd StagC4 off!:SitC. Calculation. l~2 zotai lot. size due to .type Bdrainage -- 3S484r~ =17,424 fi'` ~, I'redevel.Qtttttent: Itunoff~Joltuxte ~ (1:2 (no impen,~ious surface) * 17,~k24 ft~*9.3 ia.li2in.lll V = 27(1Q ft' Post dcvel mcnt: Runoff Volume = D.15 (5(1°~, unpervous surface) * 17,24 ft~ *9.3 it-,Jl2ut.(ft V=$1021" Delta Voltnnc = 8It12 fts - 270(1 ft~ ~ 5rt02 ft3 (This is the volume-af storagz that must be provided for this lot,: either on the building site, or with Public "Vl~'orks approval, offst`te). Required Docuxnent~tian: Include a bloclG or sectioA an the Paving. and Drainage Plan showwfing the requrernentsnd sttzount of storage provided. (See example below) Stormwater Stora a Re uirements ftrea Percent lm en ions runoff Volume >sredevelo meat fit'' F Past UeYel meat Ft` fi'r' Stora a VolttmaRe aired: F Stora a Volume Provided: F# `:. 1 0