20021271 Ver 1_More Info Received_20021120

SPAULDING & NORRIS, PA
Civil Engineering & Planning
November 20, 2002
Mr. Todd St. John
NC Division of Water Quality
Central Office
2321 Crabtree Boulevard
Suite 250
Raleigh, NC 27604-2260
Re: 401 Water Quality Certification for Autumn Park PUD
Holly Springs, Wake County
DWQ # 02-1271
S&N Project # 308-01
Dear Mr. St. John,
Spaulding & Norris recently received a copy of the "Approval of 401 Water Quality Certification
and Neuse Buffer Rules with Additional Conditions" for Autumn Park PUD in tlolly Springs
(Wake County), dated October 3, 2002. After a review of the standard Conditions of Certification
for WQC #3362, particularly standard Condition of Certification #3, the Owner intends to reduce
the project's total impervious surface to less than 30 percent. We understand that if the project
will have less than 30 percent impervious coverage at completion, additional condition #2 per the
October 3, 2002, 401 Water Quality Certification will no longer be required. The reduction in
impervious coverage will be achieved by slightly reducing the average home size and by
constructing homes closer to the front yard setback than was originally planned for this
development. This change in home placement will reduce the length of all driveways by
approximately 10 feet. These measures alone reduce the total impervious coverage for this
project to less than 30 percent. Additionally, the Owner is currently seeking approval from the
Town of Holly Springs to change the proposed greenway from an impervious asphalt surface to a
pervious surface material (mulch, wood chips, gravel, etc.) which would further reduce the total
imperious surface area for this project. Supporting calculations are attached to this
correspondence for your review.
The Owner requests that this letter be accepted as a formal request that DWQ abrogate additional
condition #2 of the "Approval of 401 Water Quality Certification and Neuse Buffer Rules with
Additional Conditions" for Autumn Park PUD, dated October 3, 2002. Thank you in advance for
your time spent reviewing this request. Please do not hesitate to call me if you have any
questions, comments or concerns about this request.
Sincerely,
Scott Mitchell, PE, LSS
Environmental Engineer/Scientist
cc: Mr. Mitchell Huff, Grossman Communities of NC, Inc
Phone: [phone] ~ Fax: [phone] ~ 972 Trinity Road ~ Raleigh, North Carolina 27607

Impervious Surface Calculations
for
Autumn Park PUD
Holly Springs
Wake County
Property Size = 57.755 acres or 2,515,807.8 ft2
30% of Property Size = 17.327 acres or 754,742.3 ft2
Impervious Surface Area Required for Infrastructure
Sin le Famil ftz Townhomes ft2 Total ft2
Streets 196,935 49,7:16 246,651
Sidewalk': - 36,106 7;310 43,416
Greenway 17,149 0 17,149
Total = 307,216
Impervious Surface Area Required for Homes
Number of Lots Average ~unperyio. a~ Total Impervious Area
Area er Lot" ft~)i ftz
Single Family 194 _ 1,900 368,600
Townlomes 50 1,5ti0 75,000
TAtQI = 443, 600
1 Includes all impervious area proposed for private lots (home, driveway, patio, walkway, etc.)
Total Proposed Impervious Surface Area for Project =
307,216 ft2 + 443,600 ft2 = 750,816 ft2
Percent of Property Covered by Impervious Surface at Full Build Out =
(750,816 ft2 / 2,515,807.8 ft2) x 100 = 9.8 °/