20061747 Ver 2_More Info Received_20081007

Delineations Plus
Wetland & Stream Delineation
Mapping & Consulting
Fidelity Court Suite #8 400 Davie Rd.
Carrboro, NC 27510
Mr. Ian McMillan
NC Division of Water Quality
401 Oversight / Express Permitting Unit
2321 Crabtree Blvd. Suite 250
Raleigh, NC 27604
Jonathan J. Hopkins
President
Phone: [phone]
Fax: [phone]
10/03/08 L5.111°/
0 C T 7 2008
WETLANDS AND STORMWATE BRANCH
RE: Highland Park Buffer Mitigation: DWQ Project # 06-1747, Ver. 2, Durham County
Dear Mr. McMillan,
Two items have come to my attention: 1) there are two typo errors in the table of impacts on the
second page; and 2) several of the stream crossings that have buffer impacts in the Highland Park
subdivision are under 1/3 acre in total impact for each crossing and are listed as "Allowable" under the
Redbook Table of Uses for the Neuse River Buffer rules.
Firstly, after reviewing the PCN applications, I noticed that the typo errors are: 1) the Buffer Zone
1 impacts should read 27603, not 27306. You can check this figure by dividing the required mitigation
by three. 2) The total wetland impacts for the entire project should be 0.4211 AC, not 0.583339 AC. If
you could change the wetland impact figure I would appreciate it.
Secondly, reviewing the stream crossings I found several where both Zone 1 & Zone 2 combined
are under 1 /3 AC for each stream crossing. In addition, the sewer stream crossings fit into the Table of
Uses category labeled: "Perpendicular crossings that disturb greater that 40 linear feet of riparian buffer
with a maintenance corridor greater than 10 feet in width." Although our stream crossings only disturb
30 linear feet of riparian buffer, the maintenance corridor is greater than 10 feet in width, hence these
crossings belong in this category. This category is listed in the Redbook Table of Uses as "Allowable,"
not "Allowable with Mitigation." Thus these sewer stream crossings should not be subject to mitigation.
The greenway crossings (7.5 foot wide nature paths that have no stream impact in their crossing but do
have buffer impacts) are also listed in the Table of Uses as "Allowable." These crossings, and their
associated buffer impacts, are as follows:
OFFSITE: ZONE 1 ZONE 2 TOTAL
Sewer Crossing A 2812 SF 1200 SF 4012 SF (under 1/3 AC)
Sewer Crossing B 1903 SF 1293 SF 3196 SF (under 1/3 AC)
ONSITE:
Sewer Crossing B 1928 SF 1389 SF 3317 SF (under 1/3 AC)
Sewer Crossing C 2110 SF 1416 SF 3526 SF (under 1/3 AC)
Greenway I
(Sheets 5,6,8, & 9) 2502 SF 2739 SF 5241 SF (under 1/3 AC)
Greenway 2
(Sheet 10) 550 SF 847 SF 1397 SF (under 1/3 AC)
TOTALS: 11805 SF 8884 SF
Therefore, the Zone 1 impacts subject to mitigation should be 27603 - 11805 = 15798 SF. The
Zone 2 impacts subject to mitigation should be 50449 - 8884 = 41565 SF. Applying the 3:1 mitigation
ratio to Zone 1 impacts gives a required mitigation of 47394, not 82809 as shown on the Certificate.
Applying the 1.5:1 ratio to the Zone 2 impacts gives a required mitigation of 62347.5, rounded up to
62348, not 75674 as shown on the Certificate.
If you would please make these changes to the Highland Park Certification (DWQ Project # 06-
17 , er. 2) I wo d greatly appreciate it. Thank you for you time in discussing this matter & making
ese ppropriaAcharlges. A hard copy of this letter will follow by mail.
wishes, I
than Hopkins, MPP,
Delineations Plus
PO Box 3097
Chapel Hill, NC 27515-3097
919 932-7217
[e-mail]