20110661 Ver 1_More Info Received_20120202

jficl='=�VM Jones & Cnossen
ENGINEERING PLLC
Civil Engineering I Construction Management I Land Planning
Ms Karen Higgins
NCDWQ — Division of Water Quality
1650 Mail Service Center
Raleigh North Carolina 27699
RE Request for More Information
Chastain Subdivision (DWQ Protect #2011 066 1)
Dear Karen
221 N SALEM ST SUITE 200
PO BOX 1062
APEX NC 27502
Office 919 387 1174
Fax [phone]
wwwpnescnossen com
January 31 2012
I have received your letter Request for More Information dated October 24 2011 and am herein providing the
following responses for continuation of staff's review of the project
I have reviewed the option of replacing the scour hole with a flow splitter box and level spreader
engineered filter strip And while I agree that this would be the preferable repair it also needs to be
constructible I ve mentioned in previous conversations and letters that the scour hole location has
limited construction access so any repair must utilize smaller equipment and be safe I brought a
contractor to this site and he believes that construction of a level spreader with level lip and filter
strip would be near impossible given the limited access and slope He also expressed safety concerns
and as a result would have no interest in bidding the work if this repair method was required As a
result this repair method is not recommended
a Peak flow calculations for the 1 year and 10 year storms are attached
b A 50 scale drawing of the site drainage area is attached The storm drainage network including
easements are also shown
c A 10 scale drawing of the scour hole area is attached showing existing 1 foot contours per GIS as
well as proposed contours for repair
d A section view of the scour hole is attached showing materials to be installed
e A construction section is provided on the 10 scale drawing provided under 2c
f I have requested a copy of the O &M agreement from the HOA and will provide a copy under
separate cover when received
A CD is attached with TIFF format copies of the plans
It is hoped that this information is sufficient for approval following your review If you feel that another
Request for Additional Information will be necessary to continue your review then I suggest that a meeting
be arranged to expedite repair If you have any questions or need anything else please let me know
Sincerely
1 ) 2woA
Peter D Cnossen P E
Jones & Cnossen Engineering PLLC
Cc Divida Johnson — Omega Management
Attachments
#D
FEa � D
Wes, 2 2012
"�NOSANpSr0 EIR
BRANCH

MCNEW
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H Sullins Dee Freeman
Governor Director Secretary
October 24 2011
DWQ Project # 2011 0661
Wake County
CERTIFIED MAIL RETURN RECEIPT REQUESTED
Omega Association Management
Attn Mr George Sewell
1010 Buck Jones Road
Raleigh NC 27606
Subject Property Chastain II, Raleigh, NC
UT to Crabtree Creek [030402 27 33 (10) C NSW]
REQUEST FOR MORE INFORMATION
Dear Mr Sewell
On July 14 2011 the Division of Water Quality (DWQ) received your application dated June 30 2011
with additional information received by DWQ on September 30 2011 to impact 600 square feet (ft) of
Zone 1 protected riparian buffers and 1 000 square feet (ft) of Zone 2 protected riparian buffers to
construct the proposed plunge pool and stabilization measures at the subject property The DWQ has
determined that your application was incomplete and/or provided inaccurate information as discussed
below The DWQ will require additional information in order to process your application to impact
protected wetlands and/or streams on the subject property Therefore unless we receive five copies of the
additional information requested below we will place this project on hold as incomplete until we receive
this additional information If we do not receive the requested information your project will be formally
returned as incomplete Please provide the following information so that we may continue to review your
project
Additional Information Requested
Please analyze the option of replacing the scour hole with a flow splitting box and level spreader
engineered filter strip (constructed outside the riparian buffer) This approach would be
compliant with Neuse Buffer diffuse flow requirements Also the DWQ believes that splitting
the flow would better protect the buffer from erosion and possibly be less costly than the
proposed scour hole If you choose this option then please provide a LS VFS supplement form
with all required items
2 If your analysis shows that it is not possible to implement the design suggested under Item (1)
then please provide the following information at the correct scales (or risk a return of
application)
a Calculations for the peak flow during the one inch/hour and ten year storms based on the
drainage area size and rational C coefficient
Wetlands Buffers Stormwater Compliance and Permitting Unit (WeBSCaPe) tiatcwnra 1650 Mail Service Center Raleigh North Carolina 27699 1650 S; Phone [phone] FAX [phone] S�� Internet http llportal ncdenr org /weblwglws 8/
An Equal Opportunity 1 Affirmative Action Employer

Sewell
Pag 2 of 2
October 24 2011
Plans (1 " 50 or larger) of the entire site showing
• The delineated drainage basin
• The storm drainage system including all inlets outlets and conveyances
° Maintenance access
c Plan details (1 = 30' or larger) for the scour hole showing
• One foot proposed topo lines between the scour hole and top of stream bank
• Proposed drainage easement
• Design at ultimate build out
d Section view of the scour hole (1" = 20 or larger) showing
° #57 stone
° Downslope filter fabric
e A construction sequence that shows how the scour hole will be protected from sediment until
the entire drainage area is stabilized
f A copy of the signed and notarized operation and maintenance (O &M) agreement
3 One (1) data CD of full size plans in TIFF Group 4 format (black and white not grayscale or
color) If the plans are too large to store in TIFF format they can be stored in PDF format
Please respond in writing within 30 calendar days of the date of this letter by sending a copy of this
information to me If you will not be able to provide the requested information within that timeframe
please provide written confirmation that you intend to provide the requested information and include a
specific timetable delineating when the requested materials will be provided If we do not hear from you
in 30 calendar days we will assume that you no longer want to pursue this project and we will consider
the project as returned
This letter only addresses the application review and does not authorize any impacts to wetlands waters or
protected buffers Please be aware that any impacts requested within your application are not authorized (at
this time) by the DWQ Please call Ms Amy Chapman at [phone] or Ms Karen Higgins at 919
807 6360 if you have any questions regarding or would like to set up a meeting to discuss this matter
Sincerely
w
Karen Higgins Supe sor
Wetlands Buffers Stormwater Compliance and Permitting Unit
KAH/asc
cc Lauren Witherspoon DWQ Raleigh Regional Office
Jones & Cnossen Engineering PLLC Attn Mr Peter Cnossen PO Box 1062 Apex, NC 27502
File Copy
Filename 110661ChastainIi(Wake)NBR On_Hold2

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Peter Cnossen Page 1 1/26/2012
140
1
1/26/2012
Chastain Phase
10
YI #181A
1 Year Storm
Peak Flow =
199
Outlet Size =
24
Time to Peak =
5
Incoming Pipe =
36
Time (min)
Inflow (cfs)
Storage (cf)
Stage (ft)
Outflow (cfs)
0
00
0
0
0
0
05
05
0
000
00
14
1
19
14
002
21
-6
15
42
8
001
16
78
2
70
86
012
51
55
25
100
141
019
66
102
3
129
243
033
86
130
35
157
373
051
107
152
4
179
524
071
126
158
45
195
682
093
144
152
5
199
834
1 14
160
118
55
195
953
130
171
74
6
179
1026
140
177
6
65
169
1033
140
178
25
7
147
1008
1 37
175
84
75
127
923
126
168
121
8
109
802
1 09
156
141
85
96
661
090
142
139
9
84
521
071
126
128
95
72
394
054
110
114
10
6 2
280
038
92
92
105
54
188
026
76
66
0140 RTG

Peter Cnossen Page 2 1/26/2012
11
48
122
017
61
-40
115
40
82
011
50
31
12
36
51
007
40
11
125
30
40
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35
15
13
26
25
003
27
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Peter Cnossen Page 1 1/26/2012
140
1
1/26/2012
Chastain Phase
10
YI #181B
1 Year Storm
Peak Flow =
180
Outlet Size =
18
Time to Peak =
5
Incoming Pipe =
42
Time (min)
Inflow (cfs)
Storage (cf)
Stage (ft)
Outflow (cfs)
0
00
0
0
0
0
05
04
0
000
00
13
1
17
13
001
10
22
15
38
35
004
16
65
2
63
100
010
27
107
25
90
208
022
39
153
3
117
360
037
52
196
35
142
557
058
64
234
4
162
791
082
76
257
45
176
1048
109
88
265
5
180
1313
137
98
245
55
176
1558
162
107
208
6
162
1766
184
114
144
65
153
1909
198
11 9
103
7
133
2012
209
122
34
75
11 5
2046
213
123
23
8
99
2023
210
122
70
85
86
1954
203
120
101
9
7 6
1853
193
117
124
95
65
1729
180
113
144
10
56
1585
165
108
157
105
49
1428
148
103
162
0140 RTG

Peter Cnossen Page 2 1/26/2012
11
43
1266
132
97
160
11 5
36
1105
1 15
90
163
12
32
942
098
83
153
125
27
789
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76
148
13
23
642
067
69
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Peter Cnossen Page 1 1/26/2012
140
1/26/2012
Chastain Phase
10
YI #181A
10 Year Storm
Peak Flow =
302
Outlet Size =
24
Time to Peak =
5
Incoming Pipe =
36
Time (min)
Inflow (cfs)
Storage (cf)
Stage (ft)
Outflow (cfs)
0
00
0
0
0
0
05
07
0
000
00
22
1
29
22
003
26
9
15
63
31
004
31
99
2
106
129
018
63
129
25
151
258
035
89
187
3
196
445
061
117
239
35
239
684
093
144
282
4
27 2
966
131
172
300
45
296
1267
172
197
298
5
302
1565
213
219
250
55
296
1815
247
235
182
6
272
1997
272
247
75
65
257
2072
282
251
16
7
223
2088
284
252
87
75
193
2001
272
247
161
8
166
1839
250
237
212
85
145
1627
221
223
234
9
127
1393
190
206
238
95
109
1155
157
188
237
10
94
918
125
167
221
105
82
697
095
146
193
0140 RTG

Peter Cnossen Page 2 1/26/2012
11
72
504
069
124
155
115
60
349
048
103
129
12
54
221
030
82
83
125
45
138
019
65
59
13
39
79
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49
0140 RTG

Peter Cnossen Page 1 1/26/2012
140
1
1/26/20U
Chastain Phase
10
YI #181 B
10 Year Storm
Peak Flow =
256
Outlet Size =
18
Time to Peak =
5
Incoming Pipe =
42
Time (min)
Inflow (cfs)
Storage (cf)
Stage (ft)
Outflow (cfs)
0
00
0
0
0
0
05
06
0
000
00
18
1
24
18
002
12
38
15
54
56
006
20
100
2
90
156
016
34
167
25
128
323
034
49
237
3
166
561
058
64
306
35
202
867
090
80
367
4
230
1234
128
95
405
45
251
1639
170
110
423
5
256
2062
214
123
398
55
251
2460
256
135
349
6
230
2808
292
144
259
65
218
3068
319
150
202
7
189
3269
340
155
102
75
164
3372
350
158
18
8
141
3390
352
158
52
85
123
3338
347
157
102
9
108
3236
336
154
141
95
92
3095
322
151
177
10
79
2918
303
147
202
105
69
2716
282
142
217
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Peter Cnossen Page 2 1/26/2012
11
61
2499
260
136
223
11 5
51
2276
237
130
235
12
46
2041
212
123
230
125
38
1811
188
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232
13
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108
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JONES 8.
CNOSSEN
Subject
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CONSTRUCTION 5EQUENCE
1. CONSTRUCT ROCK DAM AT BREACH IN EXISTING CREEK BANK.
2. GRADE BANKS OF EROSIVE FEATURE TO MAXIMUM 2:1 SLOPES.
3. INSTALL MIRAFI I I OON OR EQUIVALENT GEOTEXTILE LINER ON
NEWLY GRADED SLOPES.
4. INSTALL G -8" OF WASHED STONE (NO. 57) ON BOTTOM TO
CU5HING FOR PLACEMENT OF RIP -RAP.
5. INSTALL RIP -RAP (CLASS 2) AND SHAPE TO PROMOTE ENERGY
DISSIPATION THROUGH SCOUR HOLE.
G. SEED AND STRAW DENUDED AREA5 OUTSIDE SCOUR HOLE THAT
MAY HAVE BECOME DISTURBED DURING REPAIR OPERATIONS.
Naeueum NOYES"
OYFRT RUNOFF FROM UNOW SED AREAS AWAY FROM TE NAN
((Rp DETAL O10oaro •SiANDMD 2010N M1011 DELAY
(7F.Fi=POD AREA UIFR OAII 6 N PLACE
FOTAYATE F'WIDATDN FOR ARM AND USE R AS A TEIIPORAY
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Cowan LYF FLTLR FALRMC. OYr76M T FT AT ALL JONIS. UPSmm
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SRDOTH THE FORDAURON AEA OEFOE PLACM FLTER FAMSC.
RE CAFRL PUONO ROCK QI FAdSC. R YAY RE IEIPFiL 'D PLACE
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CMATRUOf EM ANOEILT 7O DREN901S 3lIOMI DN PLANS
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SPRLRAY CREST AND AT LEAST 1 FT NO" T,A THE
DCOMRFAN FACE OF NN AT ALL PONS. (SEE NJ W)
BMW SONEIlf -{ADEN FLM TD UPPER DO OF RAWL
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PLAN WITH SPILLWAY DETAIL
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NOTES
5,4x/
1. All construction and materials shall conform to City of
509 \ / / / / / / / O/ �' _ _ - - - - - - - Raleigh Standards and Specifications.
' \ \ / 2. Phase 10 is to be mass graded a5 shown and the
��° 1 542 / / ` _ I / / - elevations listed in each lot represent the design elevation of
/ ) ! / \/ CB / / \\ I / / / _ the finished graded pad.
�c
/ / // # 167 \ I i / I , 3. Total disturbed area of Phase 10 is 25.71 acres which
/ ) / includes grading of streets and lots.
5 / o r�53 / // // / 4. Erosion control permitting will be done as a separate
r I I \ I `� submittal.
CB 07 I I / , I / �� I I / // / 5. Owner is responsible for the installation and maintenance
#V 58 1 \ ro / I / I / / / of erosion control devices.
G. 5tormwater mana ement requirements will be met over
51 � ( �2 / 9 a by
� /V , / / � • 9 I ` 1 / / sizing storm dramage pipes to provide temporary storage of
�'Ci I \� I i excess run -off (post - pre development flow). The maximum
- - --
\ 1 1 506 g' \ , / / O I \ I runoff coefficient from development shall not exceed 0.30.
\ ` \ \ \ \ - _ - / I U545\\ 1 2 , 550 / \ I Outlet flow rates from inlets as follows:
1 \ I 1 #I66 / / / 1
Sri 13 \ \ I � I rn� I PIPE PIPE
\� \ \ I \ \ / / / / I I
`- - 1 -I - \ 50 _ _ _ _ 546 / i ,1226 / 5 // 549 I J f INLET Q) a roar) (IN) PROVIDED OUTLET
I / t (cis) (cfs) (IN) (IN) SIZE (m)
1 / / / / I / 159 18.0 9.9 18 36 15
65 I ` / J 1 - / / � GO I 6.8 13.1 18 36 18
#A5 / / / / / I 161 14.9 9.2 18 36 15
/ 1 / r 165A 21.1 11.0 18 42 15
5/� 7 / __ \ / / 1855 30.2 9.7 18 36 24
521 ��20� 15191 I 518\ \ I I I e14 1818 25.6 15.8 18 42 18
O 5)7 15116 511.5 2 \ l-2 /
/ \ ) \ / 1858 7.2 3.8 15 30 10
\ / / 1888 3.2 1.8 15 24 8
50� 503 ` / / 2 \ %� 1 / I 1898 6.8 3.6 15 30 10
I I I 1 l U2 501 5�0 / / j
#15 - - , ^ 3 498 49 -' 234.8 / !i
X
/cn
#15,3 Reduction may be achieved by Inserting a short
I 1 / ► �r- I - - _ 152 cB section of PVC pipe In the outgoing pipe and
i / / ti� / `� ' C, T I- - / / mortarincj the voids ace around the PVC pipe.
I I i I 1 1
-237. X 2 5.7
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