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HomeMy WebLinkAboutSDP202000011 Review Comments Critical Slope Waiver 2020-02-28 Christopher Perez From: Christopher Perez Sent: Friday, February 28, 2020 1:36 PM To: Craig Kotarski; Kim Mellon Cc: John Anderson; U Lopez; Frank Pohl Subject: Boys and Girls Club Critical Slopes Waiver Craig/Kim, Please give me a call about the Critical Slope Waiver... The SWM drainage pipe's critical slope disturbance is not included in the waiver request but I believe it needs to be. Please include it and depict it on exhibit#1, exhibit#2,Image#1 & Image#2 in the request itself, and the 0.45 ac calculations updated. This item is not exempt under Section 4.2.6(c). Give me a call to discuss and then send over the revised documents. Thanks Christopher Perez I Senior Planner Department of Community Development I County of Albemarle,Virginia 401 McIntire Road I Charlottesville,VA 22902 434.296.5832 ext.3443 1 Sec.4.2.6-Exemptions. SHARE LINK TO SECTION PRINT SECTION DOWNLOAD (DOCX) OF SECTIONS EMAIL SECTION A lot,structure,or improvement may be exempt from the requirements of section 4.2 as provided herein: (Added 10-17-01) a. Any structure which was lawfully in existence prior to the effective date of this chapter and which is nonconforming solely on the basis of the requirements of section 4.2,may be expanded,enlarged, extended,modified and/or reconstructed as though such structure were a conforming structure.For the purposes of this section,the term"lawfully in existence"shall also apply to any structure for which a site development plan was approved or a building permit was issued prior to the effective date of this chapter,provided such plan or permit has not expired. b. Any lot or parcel of record which was lawfully a lot of record on the effective date of this chapter shall be exempt from the requirements of section 4.2 for the establishment of the first single-family detached dwelling unit on such lot or parcel;provided that section 4.2.3(b) shall apply to such lot or parcel if it contains adequate land area that is not in critical slopes for the location of such structure. For the purposes of this section a manufactured home shall be deemed a single-family detached dwelling unit. c. Accessways, • •lic utili lines and a I .urtenances,'stormwaillinagement facilities,and any other public facilitie ." ' •< ` : P I " •arcel shall not be required to be located within a building site and shall not be subject to the requirements of this section 4.2.2,provided that the applicant deaallitrates that no reas I . alignment e tThe county engineer shall require that protective .nd restorative measures be installed and maintained as deemed necessary to insure that the 4 evelopment will be consistent with the intent of section 4.2 of this chapter. (§20-4.2.6, 12-10-80; § 18-4.2.6, I d. 98-A(1), 8-5-98; Ord. 01-18(7) , 10-17-01; Ord. 14-18(2) , 3-5- 14) Christopher Perez From: John Anderson Sent: Friday, February 28, 2020 10:05 AM To: U Lopez; Craig Kotarski Cc: Christopher Perez; Frank Pohl; Kim Mellon Subject: RE: Critical Slope Waiver Request [ SDP2020-00011] ; RE:WPO202000005 - Boys and Girls Club, Northside, VSMP/WPO LJ,thanks for your kind note. Coordination with Planning is complete, CV updated. Craig, Yes,thank you for such excellent, supportive response. And yes,though a meeting now is not critical, at pre-construction, or better, as VSMP/WPO plans develop, Engineering seeks assurance that design and site contractor ensure reverse slope benching, `keying' fill into existing critical slopes, and a light construction presence across base of critical slopes(where proposed 2:1 slopes tie into existing slopes)are forefront measures. Thanks Craig Thanks,everyone From: U Lopez<Ilopez@milestonepartners.co> Sent: Friday, February 28,2020 9:43 AM To:John Anderson<janderson2@albemarle.org>; Craig Kotarski<craig.kotarski@timmons.com> Cc:Christopher Perez<cperez@albemarle.org>; Frank Pohl<fpohl@albemarle.org>; Kim Mellon <Kim.Mellon@timmons.com> Subject: Re: Critical Slope Waiver Request [SDP2020-00011] ; RE: WP0202000005- Boys and Girls Club, Northside, VSMP/WPO John: Thanks for your thoughtful review and consideration of the request. I am happy to see that additional exhibits and background explanation and analysis was able to change the recommendation from denial to approval. Please let us know if additional info is needed as you coordinate internally with Planning. Craig: Thanks for working with John on this and turning around the response as quickly as you did. I am happy that our design work diligence paid off and we were able to demonstrate the limited impacts as the best solution for the site. Chris: My understanding is that a waiver application supported by Staff is placed on the BOS consent agenda. Is this correct? Do you know what BOS agenda we might be on? I want to get it on my calendar. Best -U U Lopez milestone partners 434.245.5803 T 434.409.1005 C 1 oy A(,&A, County of Albemarle Department of Community Development Memorandum To: Chris Perez,Community Development Planning and Zoning Review From: John Anderson,Community Development Engineering Review Date: February 28,2020 Subject: Boys and Girls Club (SDP202000011)—Critical Slopes Impact Review The critical slope waiver request has been reviewed.The applicant proposed design with 2:1 fill slopes across 0.45 Ac.of critical slopes. The engineering analysis of the request follows. Analysis draws on information and attachments included with Timmons Group email,received 2/27/2020 4:05 PM. Description of critical slope area and proposed disturbance: The critical slopes proposed to be impacted are natural and for all intents, undisturbed stabilized wooded forest that descend to streams. The applicant proposes critical slope impacts to construct slopes to support a main building,parking,and associated improvements;proposed design does not include retaining walls. Areas Acres Total site 216.69 Critical slopes Xxxx sf xxx%of total site Critical slopes disturbed 0.45 Ac. xxx%of total site Exemptions to critical slopes waivers for driveways,roads and utilities without reasonable alternative locations: The proposed disturbance is not exempt as defined in Section 4.2.6. Compliance with Zoning Ordinance 18-4.2: "large-scale movement of soil and rock" Existing critical slopes are stable. Proposed 2:1 fill slopes steeper than existing critical slopes may increase movement of soil if constructed without care. Reverse bench slopes and other steep slopes appropriate standards at 18-30.7.5 bring sound construction principles to bear. Applicant and VSMP /WPO design acknowledge this. "excessive stormwater runoff' Post-developed runoff will be detained and routed to base of slope. Critical slopes should see no increase in runoff, or excessive runoff. Ref. Timmons email,2/27/2020 4:05 PM. "siltation of natural and man-made bodies of water" Applicant explains role of geotechnical engineer,describes `keying in' fill,and reverse benching (every 9'). Reverse benching is small-scale terracing helps prevent siltation. Design will specify blanket matting. The ACDSM stipulates that constructed slopes steeper than 3:1 require stabilization hardier than grass. Applicant intends to propose reforestation with canopy tree species. These slope stabilization measures will be evaluated with the VSMP/WPO plan to ensure that the final approved design promotes long-term stability to minimize risk of siltation. "loss of aesthetic resources" 2:1 well-designed,benched, and reforested slopes should not disrupt existing aesthetic,whereas retaining walls might. "a greater travel distance of septic effluent" The proposed buildings and site rely on a pump station with force main connection to existing public sanitary sewer system.A bend in proposed force main lies approximately 15'-20'from proposed 2:1 fill slopes(on critical slopes);effluent release to 2:1 fill slopes has potential to travel a greater distance than it otherwise would on more gentle fill slopes. If standards at 18-30.7.5 are incorporated into design, potential impact from septic effluent release is essentially neutral in the post-developed state, compared with existing condition, since reverse slope benches (grading) tend to intercept and mitigate the distance septic ernuent release could travel. Based on review,Engineering recommends waiver approval. VSMP/WPO plan and site plan design will include notes,specifications,linework and requirements for appropriate resource-protective measures. Critical Slope Waiver Review Letter-Boys and Girls Club 022R20 Christopher Perez From: John Anderson Sent: Friday, February 28, 2020 8:59 AM To: Craig Kotarski Cc: Christopher Perez; Frank Pohl; U Lopez; Kim Mellon Subject: RE: Critical Slope Waiver Request [SDP2020-00011] ; RE:WP0202000005 - Boys and Girls Club, Northside, VSMP/WPO Craig, Email below with attached graphic/plan Alternatives exhibits provides sufficient basis for Engineering to support critical slopes waiver request, as proposed,2/24/20. Waiver request consists primarily of 2:1 fill slopes without retaining walls, impacting Ac. Constructing retaining walls, an Engineering preference to avoid or minimize impacts to steep or critical slopes, are not well-suited to this site, or in this instance. Retaining walls present: • Additional impact to critical slopes(under one scenario, increasing impact threefold,to 1.54 Ac.), • Inherent risk to children who use the facility, daily. Walls are a curiosity that present/invite fall risk, • Construction challenges, • An option with minimal advantages given that storm runoff will be detained and conveyed to base of slope via non-erodible channel/storm pipe, and • A less than optimal approach to multiple design goals, including: constructability, safety, maintenance, resource protection,and economic viability. Note: VSMP/WPO plan review comments will insist on construction standards listed at 18-30.7.5, which are fundamentally necessary when proposing 2:1 fill over a 45' vertical interval across steep(in this instance, critical)slopes, and are appropriate resource-protective measures when recommending critical slopes waiver approval. [Glad in response, below, to read(Timmons text): `Engineering requests design conform with standards at 18-30.7.5.c./d. Per the detail attached this is what we are specifying...additionally,the drainage strategy does not allow any concentrated flow to outfall on these slopes. That detail is not yet on our plans, but will be as we move forward.' ] Please accept this email notice that Engineering supports Timmons design approach,which minimizes critical slope impacts. Alternatives were considered. Engineering,based on response, below(alternatives analysis,technical rationale, site-topography-elevation-constructability constraints), supports Timmons Group Boys and Girls Club—Northside, Critical Slopes Waiver—Special Exception Request,d. February 24, 2020. Engineering will coordinate review comments /recommendation internally with Planning waiver and site plan coordinator, Christopher Perez. Thank you for such thorough response addressing listed concerns, a response mindful of process that requires Engineering to recommend approval or denial of a critical slopes waiver request based on technical merits. Your response should help keep review and approval timelines on track. Please feel free to call if any questions. Thanks, again best,J. Anderson 434.296-5832-x3069 From:Craig Kotarski<Craig.Kotarski@timmons.com> Sent:Thursday, February 27, 2020 4:05 PM To:John Anderson<janderson2@albemarle.org> Cc:Christopher Perez<cperez@albemarle.org>; Frank Pohl<fpohl@albemarle.org>; U Lopez <Ilopez@milestonepartners.co>; Kim Mellon<Kim.Mellon@timmons.com> Subject: RE: Critical Slope Waiver Request [SDP2020-00011] ; RE: WP0202000005 - Boys and Girls Club, Northside, VSMP/WPO 1 John,thanks for the feedback below. I've put together some responses,as we have looked at and evaluated other options. Let me know if this changes anything from your perspective or if these items should be woven into the request for the waiver. Is it worth us getting together to discuss to better unpack the safety concerns, as well as clearly ensure the safe guards we are putting in place for slope stability are communicated and clear? Thanks for your thoughtful review of all of this. Best, Craig From:John Anderson<]anderson2@albemarle.org> Sent:Thursday, February 27, 2020 11:06 AM To: Craig Kotarski <Craig.Kotarski@timmons.com> Cc: Christopher Perez<cperez@albemarle.org>; Frank Pohl <fpohl@albemarle.org> Subject: Critical Slope Waiver Request [SDP2020-00011] ; RE:WP0202000005- Boys and Girls Club, Northside,VSMP /WPO Craig, Engineering cannot support the critical slopes waiver request for this project in its current form,under current proposed design. • While acknowledging relief from strict application of critical slopes preservation requirements should be granted to a degree to help ensure safety of boys and girls attending the Club,no alternatives are presented. We have studied other alternatives. I've attached two. One shows a 3:1 slope,however we impact 3x as many critical slopes(1.54 acres), while also infringing into the WPO buffer and the stream itself. The other option,which considered the wall,featured a pond that creates constructability and maintenance issues due to its location. (below,2/11, county staff wrote, `public safety is always the highest public purpose, in my view' —Engineering supports a site design that is inherently safe for those who routinely visit or use the facility.) • Please consider alternatives. Present several at least. Nominate preferred alternative to current design. Engineering cannot support current design with recommendation of waiver approval,absent alternative consideration. Alternatives attached. Note:Alternative analysis is a technical and not economic or cost-benefit analysis. Agreed,however the issue of safety can be subjective,as there are several technical ways for us to reduce the impacts to the slopes,but not without sacrificing the safety concerns that the club has to a large extent(30' wall)or even smaller extents(6' walls). Overall, the average wall height is around 20'...even if it is tiered it creates safety issues and concerns. • Waiver request gives no indication cost influenced design to this point. In fact, letter from James R. Pierce,CEO,Boys and Girls Clubs of Central Virginia,d. 2/21/20,makes persuasive arguments that are not economic in the least. There was a cost trade off,although exact dollars were not measured,as the elimination of the wall(and pond)was traded for the underground stormwater detention system underneath the play field. This felt like an appropriate trade of costs,as this was determined to be a safer layout. • Yet it appears proposed design eliminates all retaining walls,not just very high walls(20'-30' single, standalone retaining walls). The average retaining wall that was required along the back of the site was around 20',making the wall, in its entirety,substantial. • Please consider range of design approaches available. A hybrid approach the relies on walls of modest height placed farther from main activity areas/main building with less steep grading across critical slopes would position design favorably relative to critical slopes requirements, and position Engineering to support an alternative design. The best hybrid approach would include some amount of tiered walls and setting those walls off from the edge of the Club, however this is cost-prohibitive as an excessive amount of fill material would need to be imported in to shift walls out. While these costs have not been completely vetted,if we assume 60' of gently sloped area from the curb's edge (approximately 300')at an average of 20' of fill,then we are looking at bringing in approximately 20,000 cy of dirt, which would equate to approximately$800,000,not to mention the additional cost of the wall,which is nearly $500,000. Those costs would represent a significant amount of the Club's budget and require them to significantly reduce the program and the number of students that could be served at this facility. • Engineering,reviewing VSMP plan and waiver request,notes nearly all impacts to critical slopes are in fill sections, that virtually all fill on critical slopes is 2:1 (image, below). 2:1 slopes would uniformly steepen existing critical slopes. 2:1 fill slopes are problematic in multiple if not most settings. We have worked with the geotechnical engineer 2 to develop a detail for keying in the fill along these critical slopes,as we too recognize the importance of installation here. I've attached a detail that shows benching in every 9' along this area. • Once constructed,if erosion establishes patterns across 2:1 fill slopes,it is hard to reverse or stabilize 2:1 slopes. The situation is made worse in this instance:fill placed on slopes rated susceptible to erosion,are then made steeper. We understand the concern and have made commitments to ensure that these slopes are blanket matted,as well as that the areas are reforested. While the reforestation will take time to extend roots and assist in the stabilization of the slopes, blanket matting and seeding will also be used to assist with the early maintenance of the slopes. • Albemarle is engaged with minor to severe 2:1 (even 3:1)fill slope erosion at several commercial and residential projects where slopes include significant vertical intervals. While I am not sure of the other project specifics, in this example there will be no upstream flow discharged to these slopes,meaning the only stormwater that will engage these slopes is what will fall on it. All other stormwater associated with the upstream disturbance of the Club, its parking area,and outdoor amenities will be internally captured and discharged down at the stream. This strategy will actually reduce the stormwater flow that the critical slopes currently see. • Most remedies have not worked to halt erosion on 2:1 fill slopes,not even after multiple attempts. Experience guides response to proposed design/critical slopes waiver request. • Fill slopes are more susceptible to erosion,since fill is less stable than cut underlain by consolidated,undisturbed ground;this is why VESCH prohibits emergency spillways for SWM facilities in fill sections. Agreed,however as described in one of the previous bullets,the stormwater that will run through these areas is minimized,as it takes on no upstream flow. • Engineering is not positioned to recommend approval of critical slopes waiver than proposes no walls of any height in any location(even modest 5-6' walls,or series of 3 or 4,5' high walls). • Tiered walls of modest height could, in less than 20',eliminate elevation gain of 20'. • If tiered walls are spaced,located not immediately adjacent to main activity centers/main building,and are protected (access to tops of walls restricted)with landscape fencing,risk to girls and boys attending the facility,if not eliminated, is minimized. We weighed these options and considered fencing,but that to presented potential problems. One of those problems was that the area for fencing and/or potential landscape increases wall height,while the fence provides something to climb,creating additional safety risks for the Club. • There is no eliminating malicious intent of any human being. Walls are attractive to children. Children are curious. Alternatives should consider wall placement,shielding walls,restricting points of access along walls, especially tops,and at wall ends. • Thought and care in design can significantly limit risk posed by tiered walls of modest height. • Engineering recommends consider and present concepts that rely on slopes no steeper than 3:1,and tiered walls of modest height. Engineering intends to recommend waiver approval of less-steep proposed fill slopes if a portion of design objective is met through retaining walls of modest height. • Engineering will not recommend strict application of critical slopes requirements to this project,or insist that a hybrid 3:1 slope-retaining wall design be limited to 0.45 Ac.critical slope impact. • If revised impact exceeds current estimate of 0.45 Ac.,yet proposed(3:1)grade has a better chance of long-term stability,if wall heights do not pose same risk as risk posed by 20'-30' walls,then Engineering will recommend the preferred design alternative for critical slopes waiver approval. Note:For the moment, Site and WPO plans received 1/31 and 1/22,respectively,take an all-or-nothing approach to retaining walls. There is surely a middle-ground alternative design approach that address myriad facility use,safety, resource protection,and technical county code objectives. While tiered walls and 3:1 slopes all would help, in this specific situation the feasibility is difficult due to two factors, 1)tiering walls and increasing the slope will result in more impact not only to the critical slope,but the entire down hill side. This will result in a larger area of disturbance, which will not allow stormwater requirements to be met,as a larger area of undetained flow will be generated from those limits. Additionally,the larger grading impact will remove more mature vegetation from the hillside. 2)The cost of adding the walls and necessary imported fill would typically make this a cost prohibitive procedure. When considering alternatives,please: • Apply 18-30.7.5 steep slopes standards,which are wholly appropriate for waiver request proposal that must reflect best engineering practice to limit potential for erosion,and increase likelihood of post-developed slope stabilization. All items at 18-30.7.5 are relevant(a./b./c./d.). • Estimate total area of critical slopes that exist on TMP#06000-00-00-078A0;this value is reported in table format in Engineering recommendation to Planning,along with proposed impact to critical slopes(0.45 Ac./current design), (An estimate of total area of critical slopes that exist on this 216.69 Ac.parcel provides context(-0.45 Ac.impact) relative to overall presence of critical slopes on the parcel under development.) While I understand the request of this 3 exercise,the Club does not have access to any locations on the parcel, as this is the location that ACPS has been willing to lease to the Club. • Parcel acreage=216.69 Ac. A guess without real basis is 3-5%of this parcel is comprised of slopes steeper than 4:1 (critical). • Could Timmons use county GIS topographic data layer to analyze extent of critical slopes on this parcel,as a percentage? Note:A close approximation is helpful,provides context,and is far better than a guess. Also,image caption,below. Left:GIS critical resource map turned on;Right:GIS critical resource map with floodplain/stream buffer layers off. Image right emphasizes presence of critical slopes. It's possible more than 5%of the total area of this county-owned parcel is steeper than 4:1 (25%),or more than 10 Ac. of the parcel is in critical slopes. It would be helpful to know. It would be helpful to report that proposed design impact of 0.45 Ac. is<5%of critical slopes that exist on-site,for example. Engineering would also like to frame impact to critical slopes in context of site development LOD,6.49 Ac. 7%of area of disturbance is on critical slopes. 93%of proposed development avoids critical slopes. 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'/ jfJ ��/ - - 1 - - - _ f_� - 7 / _ _ _ _ _ . <jjL _ Iji/// - - _ ` - -_- — PS / / _W_' - _ _ - _ _ _ _ )7 ,, //// ' _ _ _ _ /� _ - _ s� _ _ - � _. - - - _ _ _. _ — I - '4(..A .-'__,-,-;______ '- , , . ' 9 SF IP$ _ #,,,.t.z,"6....., ,----... :0000000„ :", t s• O • j��'` l' '41 _ L si.1-�" •-,- ..---' -�'�j� PS i . 00 o_' Sys //�—`,/�- .,,��- .�'' :s ill II` �, = - // �"'"!� :.,..: „ -------__ _ _ y PS .� --'"" PS - � -�_ .� / NM ii -__ 0 .\IS\ ,,, SF -� �� --'�� - = Thanks,Craig best,J.Anderson 434.296-5832-x3069 John Anderson,PE,Civil Engineer II • (434)296-5832-X3o69 Community Development Dept. I Engineering Division County of Albemarle 14oi McIntire Road Charlottesville,Virginia 22902-4596 From: Craig Kotarski<Craig.Kotarski@timmons.com> Sent:Tuesday, February 11, 2020 12:45 PM To:John Anderson <ianderson2@albemarle.org> Cc: Bill Fritz<BFRITZ@albemarle.org>; Frank Pohl<fpohl@albemarle.org>; Christopher Perez<cperez@albemarle.org>; U Lopez<Ilopez@milestoneoartners.co> Subject: RE:WPO202000005- Boys and Girls Club, Northside,VSMP/WPO One question we have, as we prepare our special exception, is the reference to section 32.3.10(d), within 4.2.5.a.1 below. In looking for that,that section does not exist...is that actually pointing to a different section? Any help or info would be great. 7 • Thanks! Craig From:John Anderson <ianderson2@albemarle.org> Sent:Tuesday, February 11, 2020 10:32 AM To: Craig Kotarski <Craig.Kotarski@timmons.com> Cc: Bill Fritz<BFRITZ@albemarle.org>; Frank Pohl<fpohl@albemarle.org>;Christopher Perez<cperez@albemarle.org>; U Lopez<llopez@milestonepartners.co> Subject: RE: WPO202000005- Boys and Girls Club, Northside,VSMP/WPO Craig, Thanks for your note. Since it may be difficult to establish or argue 18-4.2.5.a.3. - b./c. as rationale for granting a modification, or waiver,your email may indicate likely best path(rationale)for granting a modification,or waiver; a./d.: public safety is always the highest public purpose, in my view. Thanks again for your note. best,J. Anderson 434.296-5832 -x3069 Sec.4.2.5- Modification or waiver. Any requirement of section 4,2.t,a.2.2.4.2.3 or 4.Z.d may be modified or waived as provided herein: a. Modification or waiver by the commission.The commission may modify or waive any requirement that is not sut 1. Request.A developer or subdivider requesting a modification or waiver shall file a written request in accorc pertains to a modification or waiver of the prohibition of disturbing slopes of 25 percent or greater(hereina _large-scale movement of soil and rock, excessive stormwater run-off,siltation of natural and man-made boc and welfare factors")that might otherwise result from the disturbance of critical slopes. 2. Consideration of recommendation;determination by county engineer. In reviewing a request for a modifici commission. If the request pertains to a modification or waiver of the prohibition of disturbing critical slope factors so that the disturbance of the critical slopes will not pose a threat to the public drinking water suppli engineer shall evaluate the potential for soil erosion, sedimentation and water pollution that might result fr. of Virginia Erosion and Sediment Control Handbook and Virginia State Water Control Board best manageme 3. Findings. The commission may grant a modification or waiver if it finds that the modification or waiver wou practices: and at least one of the following: a. Strict application of the requirements of section 4.2 would not forward the purposes of this chapter or b. Alternatives proposed by the developer or subdivider would satisfy the intent and purposes of section c. Due to the property's unusual size,topography, shape, location or other unusual conditions,excluding would result in significant degradation of the property or adjacent properties:or d. Granting the modification or waiver would serve a public purpose of greater import than would be ser From:Craig Kotarski<Craig.Kotarski@timmons.com> Sent:Tuesday, February 11, 2020 8:42 AM To:John Anderson <ianderson2@albemarle.org> Cc: Bill Fritz<BFRITZ@albemarle.org>; Frank Pohl<fpohl@albemarle.org>; Christopher Perez<cperez@1albemarle.org>; U Lopez<llopez@milestonepartners.co> Subject: RE:WPO202000005-Boys and Girls Club, Northside,VSMP/WPO 8 CAUTION: This message originated outside the County of Albemarle email system. DO NOT CLICK on links or open attachments unless you are sure the content is safe. John, thanks for your email. We are in the middle of preparing a Special Exception request for the impact to the critical slopes. We have looked at retaining walls, however those walls ended up begin over 30' tall. This poses a major safety issue for the Boys&Girls Club, since they will have hundreds of students on campus during the day. Due to the nature of the overall site and the ability to tie in the grades,they were ecstatic that the retaining walls could be removed. Regarding the erosion control,the site does have its challenges. We have taken extra precaution to sit down with the contractor, prior to finalizing this design to get their input. We worked hard to place erosion control measures in locations that they can stay during construction, limiting additional earth movement. On this site, while certain slopes are "critical", all of the slopes are steep and will require care and attention to detail during the construction process. We are hoping to submit the Special Exception application next week. While there will be no action on it, prior to the SRC meeting, hopefully it gives everyone a sense and some comfort of where we are going with this overall application. Best, Craig From:John Anderson<ianderson2@albemarle.org> Sent: Monday, February 10, 2020 6:12 PM To: Craig Kotarski <Craig.Kotarski@timmons.com> Cc: Bill Fritz<BFRITZ@albemarle.org>; Frank Pohl<fpohl@albemarle.org>;Christopher Perez<cperez@albemarle.org> Subject:WP0202000005- Boys and Girls Club, Northside,VSMP/WPO Craig, Since proposed design requires Planning Commission modification or waiver of critical slopes requirements,which depend on Findings(18-4.2.5.a.3.;Also, 18-4.2.5.a.1.,2. County Engineer waiver role), has Timmons considered retaining walls rather than grading so steeply into critical slopes below contour elevation 515? We routinely see private development propose tiered(or high)walls to avoid critical/steep slopes,and it is an option when designing to avoid critical slopes. Glad to see that the proposed layout of building, paved areas, and site access nearly entirely avoids critical slopes. The majority impact to critical slopes appears to be grading(with proposed grade quite steep), which may be avoidable if design were to use retaining walls. I will review site and WPO plans,and hope to send comments by late next week, if not a bit earlier—but critical slopes are a concern. C3.2, ESC plan, phase 1, proposes substantial grading to install sediment traps on critical slopes(in preparation for upslope development). What design alternatives exist that might lessen direct yet long-lasting impact of temporary ESC measures on critical slopes? Would retaining walls allow a more measured ESC approach that causes less impact to critical slopes? Thanks for your time and patience—please feel free to share any thoughts. ( I will review site and WPO plans as soon as possible.) best, J. Anderson 434.296-5832 -x3069 C4.0 9 SHEETS C4.1, C5.0 & C5.3 • ems • 0110061 MUM � lI11. . •w� \ • • f11/4 • • • • cwocu Karr, / i • 1 C3.2 10 • . TOP QF DATA ELEVATION 5T4 50 ' .. \ --- (cc N .):::imi••••••• --,Iiimem...1 •, \ 0 4111•111.1.11111111 ,—. \ 0\ e \ \ \ STONE bVEIR % N \ N. \ \ OFT) \ \ \ .)/1\• --... _ N1H_ \ NS Im WO \i',7i•Ziiii \ \ N \ \ \ , SO Py'PE- \ \ \ .10F \ 41- --- -- , .. \ N \ \ N , \ •.: SE014ENT TRAP TM ,. N \ DRAINAGE ARE&2 N..74 AC \ \ feri.""*".11411:.........N.: TOTAL STORAGE ROVED.3472 CY \ N. • ...... i TOTAL ST0/4AGE PROVOEO.44'3 I,CY , TOP 00APA eEVATION'4113 S -, . \ \ -.... \ •-..., \ • i \I, \ \ -- — ...... . .-- -.... ....,., -.... \ ..,. MITI I III -, . 111044iti%4 %., . ......•• '..• .,..... 0 •-- 1 , - •\‘ --, -... ...„ -........... \ — - So% 7 ''' STONE WE _ -----."-----s"----."---=. V7si `'. ., _ . - " . -.. ..:\ \ ,. ,. .... , \ / , • • , \ \ .• .. , • \ \ ,, • • _.... \ \ . • • .'It..vg) - - _ _ - i • v \ \ \ ; • •% % ..-4 ,„,„,ft ri,_____ F% 4:: k ...•'' ... 1— x w / 1 \‘ \ ...... . % \ mum wil 1.11 John Anderson,PE,Civil Engineer II • (434)296-5832-x3o69 Community Development Dept. I Engineering Division 11 County of Albemarle 14oi McIntire Road Charlottesville,Virginia 22902-4596 12