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Home My WebLink AboutSW3210701_Responce to Comments_20211020J MCADAMS October 18, 2021 NCDEQ Division of Energy, Mineral, and Land Resources 512 N Salisbury Street Raleigh, North Carolina 27699 RE: Wicker Park Response to Stormwater Comments 2021210184.00 RESPONSE TO COMMENTS > 2021210184.00 The following are the response comments for the above -mentioned project. Our response comments are in bold. NCDEQ — DEMLR a Jim Farkas "As designed, the 'low -density' portions of this project do not meet the low -density design requirements as outlined in 15A NCAC 02H .1003(2) and can therefore not be considered as a low -density area." It does not appear that the curb outlet system design requirements (outlined in 15A NCAC 02H .1003(2)(d)) have been met for all curb outlet locations. Please also clearly indicate the location of the curb outlet swales on the plans. McAdams Response: Sheet C9.12 has been updated to indicate the location for each curb outlet location. Each curb outlet location has been revised to utilize a curb outlet swales which have been designed in accordance with section 15A NCAC 02H .1003(2)(d). "Please ensure that all off -site portions of the drainage areas are accounted for at their full build -out potential per 15A NCAC 02H .1003(3)(b)." Since the applicant does not own the off -site portions of the drainage areas, the applicant is unable to ensure ongoing compliance with BUA amounts in these off -site areas. While it may not seem practical, it is possible (even with the current property zoning) for these off -site areas to become more built up than allowed for in the provided calculations (and by extension, resulting in non-compliance with the permit at no fault of the permittee). It is for this reason that we generally take the full build -out potential of an off -site area to be 100% BUA. While it may seem a bit of an overestimation to assume that these off -site areas are 100% BUA (in order to meet this assumption, there would need to be future offsite modifications that are technically possible, but not very practical), we do this in an attempt to "future proof' the design and prevent the permit from becoming out of compliance at no fault of the permittee. As mentioned in the note following these and the prior comments, it is advisable to divert these off -site drainage areas around the proposed SCMs (so that the applicant has full ownership/control of the drainage areas), but that is not always possible so we allow for the off -site area to be accounted for at its full buildout potential. While it may not be practical to develop this off -site drainage area to 100% BUA, it is technically possible and must therefore be taken into consideration or diverted around the SCM. Please either divert these off -site creating experiences through experience 3430 Toringdon Way, Suite 110, Charlotte, NC 28277 / 704. 527. 0800 MCADAMS RESPONSE TO COMMENTS > 2021210184.00 drainage areas around the proposed SCMs or account for these off -site areas at their full build -out potential (these wet ponds appear to have extra capacity built-in so accounting for this "extra" BUA should not negatively impact the designs/require a redesign). McAdams Response: Sheet C9.12 has been updated to indicate all off -site drainage areas as 100% impervious cover conditions. The design calculations and construction drawings have been updated a needed. 3. "The total amount of BUA allocated to the individual lots (604,280 sf) does not correspond to the total 'New BUA on Subdivided Lots' as shown on the Supplement-EZ Form. Revise as needed." Per Line 9 of the Drainage Areas Page of the Supplement-EZ Form, the total amount of new BUA allocated to individual lots for the entire site is shown as 509,712 sf. Dividing this amount of BUA between the 118 proposed lots results in an average BUA per lot of 4,319 sf per lot. This amount is less than the BUA per lot allocated in either the high -density (4,640 sf) or low -density (4,456 sf) deed restriction documents. Please revise as needed. NOTE: As currently shown, it is unclear which lots will be covered under the high -density deed restriction document and which lots will be covered under the low -density deed restriction document. It is recommended to either combine these two forms into a single "mixed -density" deed restriction document (merging the requirements from each form int a single form) or by clearly indicating which lots will be covered under the high -density deed restrictions and which will be covered under the low -density deed restriction. NOTE: It is not recommended to "split" lots between these two different deed restrictions, each lot should clearly fall under a single deed restriction document and should have a single BUA allowance (Otherwise you'll run into weird issues with "front yard" and "back yard" BUA allowances that are prorated depending on where the lot drainage divide eventually ends up). McAdams Response: The total amount of BUA allocated to the individual lots (584,640 sf) has been updated to match the total 'New BUA on Subdivided Lots' as shown on the Supplement-EZ Form. Dividing this amount of BUA between the 126 proposed lots results in an average BUA per lot of 4640 sf per lot. This amount matched the BUA per lot allocated in both the high and low -density deed restriction documents. Each deed restriction document has been updated to clearly indicate, using lot numbers as shown in the construction documents, which lots will be covered under the deed restriction. 4. "General: Please use the latest version of this form" Please ensure that the Supplement-EZ Form contains the "Low Density" page and the required information is provided on this page. Please ensure that the required curb outlet swale calculations are provided. McAdams Response: The Supplement-EZ Form has been updated to include the "Low Density" page with the applicable data. The SIA report has also been updated to include the curb outlet swale results at the end of the report. creating experiences through experience 2 of 4 MCADAMS RESPONSE TO COMMENTS > 2021210184.00 5. "...An original signature must be provided on this form prior to us approving the permit..." A hard copy of the Supplement-EZ Form was not provided (it was also not mentioned in the letter of transmittal). Please provide a hard copy of the Supplement-EZ Form. McAdams Response: A hard copy of the Supplement-EZ Form has been provided with this resubmittal. 6. "Please ensure that the 'Entire Site' column is correctly filled out..." As noted earlier, there may be errors in the BUA accounting for the entire site. Please revise if needed in accordance with earlier comments. McAdams Response: The 'Entire Site' column has been updated to reflect the revisions included in this resubmittal. 7. Please ensure that the electronic plan sheets are separated out by type and uploaded under the appropriate file type. Dividing the entire plan set up into acceptably sized chunks and uploading the entire thing under "Other" typed plans is not acceptable since these plans will now need to be manually separated and renamed. Please use the appropriate file types for uploading plan sets and only upload the files needed to perform the review (this also applies to the hard copy submissions). Also, we require 2x hard copies of revised plan sheets (only one was provided) please provide a second copy of all applicable revised plan sheets (please do not send a second full set of plans, only the revised, relevant plan sheets are required). McAdams Response: Comment has been noted and has been addressed with this resubmittal. 8. Provide pdfs of all revisions, 2 hardcopies of revised plan sheets, 1 hardcopy of other documents, and a response to comments letter briefly describing how the comments have been addressed. a. Pdfs must be uploaded using the form at: https://edocs.deq.nc.gov/Forms/SW-Supplemental-Upload b. Hard copies must be mailed or delivered to the following address: i. For Fed Ex/UPS: Jim Farkas 512 N. Salisbury Street, Office 640K Raleigh, NC 27604 ii. For USPS: Jim Farkas 1612 Mail Service Center Raleigh, NC 27699-1612 McAdams Response: Comment has been noted and has been addressed with this resubmittal. creating experiences through experience 3 of 4 MCADAMS RESPONSE TO COMMENTS > 2021210184.00 Consideration of this response is greatly appreciated. If you should have any questions or require additional information, please do not hesitate to contact me at 540. 577. 3607. Sincerely, MCADAMS Stuart Woodard, PE Project Manager creating experiences through experience 4 of 4