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HomeMy WebLinkAboutSW6240401_Response To Comments_20240701 Request for Additional Information—COMMENT RESPONSE 07-01-2024 Stormwater Permit No. SW6240401 Maple Drive Harnett County 1. Supplement-EZ lx hard copy of the complete, original Supplement-EZ Form is required per Sections V& VI, 3 of the Application a. Cover—Line 7-8: While there is no surface water, and therefore no vegetated setbacks associated with this project, please fill in. Per 15A NCAC 02H .1017 (10), the vegetated setback shall be at least 30 feet in width. REVISED b. Low Density—Line 4: Please provide. REVISED c. Low Density—Line 5: This item should correspond to the largest calculated value shown in the table below. REVISED 2. Per 15A NCAC 2H .1003(2)(d) (ii): The longitudinal slope of the swale or vegetated area shall not exceed five percent, except where not practical due to physical constraints. In these cases, devices to slow the rate of runoff and encourage infiltration to reduce pollutant delivery shall be provided. 5.6% is greater than 5%, and the narrative indicates that measures to slow the rate of runoff are temporary. Please revise the package as needed. 3. Please provide calculations exhibiting the following: a. 15A NCAC 2H .1003(5): Stormwater outlets shall be designed so that they do not cause erosion downslope of the discharge point during the peak flow from the 10- year storm event as shown by engineering calculations. SWALE#8 IS MOST DOWNSTREAM OUTLET AT PROPERTY LINE. VELOCITY=3.6FT/S WHICH IS NON-EROSIVE. TEMPORARY SWALE LINER IS INCLUDED WITH DETAIL (C4.2) AND ESTABLISHED BERMUDA GRASS 4. Delineate the drainage area to each swale required per 15A NCAC 02H .1042(2)(g)(iv) and Section VI,8o of the Application. PROVIDED C2.0 5. Provide detail of curb outlet swale per 15A NCAC 02H .1042 (2) (h)(ii). SWALE DETAIL PROVIDED C4.2 6. Easements are needed when the property is to be subdivided or the features (such as collection systems) are on multiple properties owned OR to-be owned by multiple parties. 15A NCAC 02H.1042(2)(g)(vi), .1042(2)(1), .1050(8), and .1050(9): a. Please provide and identify an access and drainage easement along the stormwater collection systems. PROVIDED C2.0 b. Every curb outlet swale and/or portion of the stormwater collection system installed for this project shall be made accessible for maintenance and repair. Please identify the maintenance access routes and easements as well as the utility and drainage easements on the plans, if necessary. These shall have a minimum width of 10 feet, slopes that do not exceed 3:1, and extend to the nearest public right-of-way. These easements shall be granted in favor of the party responsible for operating and maintaining the curb outlet swale and/or stormwater collection system. PROVIDED C2.0 7. Please ensure that an electronic copy of all required documents, including the plan sheets, are uploaded to the electronic repository, as plans were missing from the last submission. PROVIDED 8. Please provide a Response to Comments letter indicating, in a point-by-point manner, how each of the above comments has been addressed. This item is required per 15A NCAC 02H .1042(3)(b). PROVIDED 9. 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. PROVIDED