20131070 Ver 1_Denial Letter_20141230

REAR 'J, ,
North Carolina Department of Environment and Natural Resources
Pat McCrory
Governor
December 30, 2014
CERTIFIED MAIL: 7012 1010 0002 1967 7442
RETURN RECEIPT REQUESTED
Elk Creek Development Company of Banner Elk, LLC
Angelo Accettum, Manager
PO Box 725
Banner Elk, NC 28604
Subject: RETURN OF APPLICATION
Elk Creek at Banner Elk
Dear Mr. Accetturo:
John E. Slivarla,lll
Secretary
DWR# 13 -1070
Avery County
On October 7, 2013 the Division of Water Resources (Division) received acopy of your 401 Water Quality
Certification Application for the subject project. We wrote to you-on November 20, 2013 and July 31, 2014
requesting additional information on the project. The application submittal to -date remains incomplete and
insufficient to allow us to process the application package.
The revised submittal dated October 28, 2014 and received on November 3, 2014 included improved data and
information that will better enable us to review the proposed stormwater flows and treatment. However, there are
still several significant issues where our requests for drawing and calculation revisions have not been adequately
addressed. Therefore, we are returning your application. Some of the issues that continue to be unresolved are
listed below:
Even though the issue of clarifying the drainage area size draining to the treatment pond has been raised on
several occasions, your engineer's submittal on October 28, 2014 continues to have inconsistencies on the
basic issue of the size of the drainage area of the project. For example, is the drainage area of the project
11 acres or 7.5 acres? Your engineer stated on page 9 of his response that "The retention area is for the
11.00 acres only and does not have runoff from the 12 lot subdivision." However, on page 4 of his
response, he states that "As stated above, the peak flow calculations are for a 7.54 acre project which the
multi - family area [sic] since the drainage for the platted subdivision does not flow into the multi - family
section of the project." If the Drainage Area calculations shown on page 4 of 9 are summed, the total area
of the six drainage areas of the project is 7.55 . acres which differs from the l l acre figure. The total
impervious area shown on sheet 4 of 9 (if summed) equals 125,671.36 sf or 2.88 acres. That would make
the project size approximately 38% impervious, not the 27.7% shown on the wet detention supplement
sheet. Based on the boundary shown on exhibit I of your engineer's October 28, 2014 letter, our rough
calculation of the project area is 7.5 acres.
2. Regarding the subject of size of the project area to be treated, your engineer's letter on Page 4, item c.
states that "The impervious area is calculated to be 132,717.7 square feet" However, on the "Drainage
Area Table" on sheet 4 of 9, the sum of the six drainage areas is 125,671 St. Please correct this
discrepancy.
Water Quality Regional Operations— Asheville Regional Office
2090 U.S. Highway 70, Svannanna, North Carolina 28778
Phone: [phone] FAX [phone]
Internet: htlp9 /p°rlal,ncdenroryMrehAvq
An Equal OppoM1unity l Affinative Action Employer

Angelo A=ft.
MVR# 13 -1070
Page 2 d 5
3. We appreciate your engineer providing a clearer delineation of the six different drainage areas that cover
the site. Unfortunately, most of those delineated storm drainage boundaries are not supported by final
.contours. Without supporting final contour lines, those suggested drainage basins are of minimal value
and the direction of flow cannot be certified. For example, there is nothing to indicate why the northern
portions of drainage areas #1, #2, and 45 would flow in a southerly direction. Similarly, drainage #6 has
no indication of why the stormwater would flow in the pattern indicated by the drainage area boundary. In
our July 31, 2014 letter, we specifically requested detailed drawings "showing the entire site with all
drainage areas... and all topography around the site perimeter "(emphasis added). There are still many
areas around the perimeter of the site where final contours are not present. Another example is the straight
line boundary showing the drainage separation from the single family area that was presented on "Exhibit
I ". The delineation of flows based on that straight line is not supported by final contour lines.
There is a ditch running west to east on the southern side of Elk Creek Drive as shown on page of 9 in
your October 28, 2014 submittal. Although there is an arrow on the far left -hand side of the drawing
indicating that it is a ditch, from the legend, it seems to be "Wetlands to Remain ". Please use accurate
symbols and shading to expedite the review process and ensure accuracy. This reference also refers to the
"channel installation" provided on a detail sheet "8 of 8 ". There was no sheet "8 of 8" included in the
submittal although there was a "channel installation" provided in some earlier drawings. However, this
information was not sufficient to make determination on the adequacy of the ditch to manage the flow
(See discussion below).
Similar problems with inadequate or unclear information were seen in the 4' ditch running west to east and
north of drainage areas #2 and #5. The flow was provided in the engineer's response but detailed
engineering specifications like channel depth, ditch profile, expected flow depths, type of ditch surface
have not been provided.
Similar to the Elk Creek Drive ditch, the note on sheet 4 of 9 regarding the northern "4' drainage ditch"
refers to Sheet 9 of 9 in the package submitted on June 30, 2014. However, the note did not contain the
"Channel installation" details that were provided in the package submitted in October of 2013.
Unfortunately, none of the information provided thus far addresses our need to ensure that the ditches are
designed properly. Was the "Channel installation" information that was removed from the October
submittal only meant to be for the Erosion and Sedimentation Control Plan?
4. A portion of the ditch in drainage area #2 that runs parallel to Elk Creek Drive has a section where the
western elevation is at 3700.01' and the next, eastern elevation is at 3709.21. This would indicate an uphill
flow in the ditch. Please address this apparent issue. Please provide a connected profile with elevations of
the ditch and the other two major ditches in the project. Without this information and the final contours,
we cannot determine where the flows in drainage area #2 enter the ditch or if they do at all. Similarly,
there is not enough information on the 4' drainage ditch running west to east on the northern side of
drainage area #2 to determine its elevations to enable us to confirm that it will function as intended.
Without this, we can't determine if any stormwater flow will be entering the ditch from the adjacent land
areas.
5. The southern drainage area boundaries of drainage areas #2 and #3 seem to be in the wrong location.
Shouldn't they be down the center line of the ditch? We can see nothing on the contour lines indicating
how water from drainage areas #2 and #3 could flow into the southern ditch. We've presented this before
but the engineer insists that no drainage from the Elk Creek Development is collected in that drainage
ditch. If that is the case, then the supporting drawings need to be modified.

Angelo Aa R..
DWR# 13 -1070
Page 3 of5
6. The scarcity of contour index labels has been a considerable hindrance to the review of this plan. Please
resubmit the drawings with easily - identifiable contour index labels.
7. Drawing 5 of 9 continues to include the statement "Volume provided in the filter area is 11,059.76 CF ".
We specifically asked in our July 31, 2014 letter that the inaccurate and incorrect statement be revised.
We reminded the engineer that there is no "filter area" in his plan and to remove that reference but more
importantly, the 11,059.76 CF "is not the volume provided in the wet pond." It is the minimum volume
required to be treated. Your engineer's revised drawing still inaccurately states that this is the "storage
volume of the proposed pond." Although the filter reference is minor, the inconsistencies in the treatment
volumes provided are not. In the explanation provided by your engineer to question I 1 in his October 28,
2014 letter; he states that "The Temporary Pool will contain 13,3 81 cubic feet which is 1.2 times the
amount required." This is not only in conflict with the 1 1,060 cf that he provided in the "Water Quality
Notes and Calculations" submitted with that letter but is also different from the revised "Wet Detention
Basin Supplement" sheet that was also included in his letter. The supplement sheet states that the `volume
provided" is 14,399 of Additionally, the "Pond Sizing Calculations" provided in the "SUPPORTING
CALCULATIONS for Wet Detention Basins" sheet indicates that the "WQ vol provided" is 18,705 cu
ft" Please resolve these inconsistencies.
8. The "Wet Retention Area Detail" and the "Orifice Equation" calculations shown on the most recent
version of sheet 5 of 9 contain several significant errors. First, the average head or "H" value is shown as
7.0 feet. As shown in Chapter 3 of the NC Stormwater Manual, the head is measured from the center of
the orifice to the top of the temporary pool. The "Supporting Calculations for Wet Detention Basins"
information provided in your engineer's October 28, 2014 letter show the top of the permanent pool at
3675.5' and the top of the temporary pool is 3677.5'. That would give an "I3" value of 2' not 7'. To get
an average, the Manual recommends that the "Fr' value be divided by 3. Please have your engineer
recalculate the orifice equation based on the correct values and the provisions of the state's stormwater
manual. Next, the drawing and the calculation of the orifice size are both inaccurate and would not
perform as intended. The "Notes and Calculations" on that sheet state that your project should "Use 6"
Orifice." A 6" orifice would drain the pond in a few hours, not the minimum 48 that are required. In
addition, your engineer's "Wet Retention Area Detail" shows a "4" PVC cap with hole drilled." We
would assume that this is the orifice that would control the water quality volume- release into the outlet box
but we are not sure. Your engineer's specification of "Use 6" Orifice" can't apply to the 4" pipe shown in
the drawing. In addition to this inconsistency, the "Wet Detention Basin Supplement Sheet shows a 4"
orifice in its calculation of drawdown time. There is also a 6" orifice shown feeding into the existing 15"
corrugated metal pipe (CMP). We can only assume that this was intended to be used to achieve a peak
flow rate for the local government's flood control requirements. We would strongly advise against having
an orifice at the bottom of the outlet box due to the great potential for clogging and the difficulty of
cleaning and maintenance at that location. Our review cannot continue until these critical specifics of the
water quality volume release are clarified.
9. The portion of the "Wet Retention Area Detail' drawing (5 of 6) related to the PVC outlet needs
modification. The drawing shows the discharge arm of the 4" tee stubbed into the outlet box at a level
above the permanent pool at Elev. 3675.5. This outlet pipe determines the permanent pool so they could
never be at different levels as shown on the drawing.
10. There are inconsistencies in the Retention Area Section drawings and the Wet Retention Area Detail
drawings relative to the littoral shelf. The sectional drawings show the top of the littoral shelf at 3675.5'
and the "Detail" drawing shows the bottom of the shelf at 3672.0'. The state's Stormwater BM? Manual
specifies that the "inside edge of the shelf shall be 6" below the permanent pool elevation; the outside edge
of the shelf shall be 6" above the permanent pool elevation ". The littoral shelf depth should be one foot,
not 3.5 feet as shown on your stormwater plans. The sectional drawings on sheet 5 of 9 show the top of

Mg°lo ACCW.
DWR4 13 -1070
Page 4.f5
the littoral shelf at 3675.5' and the top of the permanent pool at that same level. The plan view at the top,
right -hand side of the pond shows the "Littoral Shelf El 3674.0 ". The vegetation on the top half of the
littoral shelf would not survive the continued inundation and should be 6" above the permanent pool. Also,
the Wet Retention Area Detail shows the "Top of Vegetative Littoral Shelf Elv. 3675.0 ". There are three
different elevations shown on sheet 5 of 9 for the top of the littoral shelf.
I1. On the "Section" drawings on sheet 5 of 9, the freeboard level is shown at 3678.0. However, the "Wet
Retention Area Detail" shows the elevation of the top of the freeboard at 3678.5'. Please correct this
discrepancy.
12. In our July 31, 2014 letter regarding the absence of any engineering calculations on the adequacy or design
of the vegetated filter strip, we asked for "drawings and engineering calculations be provided showing that
there will be non - erosive flow through the 30' filter strip ". The general information on the length of
buffer is neither adequate nor consistent with the requirements of the state rules and the Manual. See 15A
NCAC 2H. 1 008(f. We have discussed this deficiency with the engineer of record but he has not provided
this information. Without this information, we cannot review the plan. We need velocity, slope and a
detailed drawing that clearly demonstrates that the device will achieve a non - erosive flow of the
stormwater to the creek. The design of any energy dissipater and flow diffusing devices must be shown in
the drawings.
13. The NC Stormwater BM? Manual requires a "detailed landscaping plan" for each wet detention pond.
The only information relating to vegetation is under the "Notes and Calculations" section of sheet 5 or 9.
The statement indicates that the list of species is for the "embankments and perimeter of the stormwater
management ". However, item A under that heading provides "Floor of Basin Reed Canary Grass and tall
fescue." This is not appropriate for the floor of the basin which will be inundated and will need no
plantings except on the littoral shelf. Also, Basin Reed Canary grass is not recommended in our
stormwater manual and is considered an invasive species by many states. The inaccurate information
provided does not qualify as a "detailed landscaping plan."
14. Your engineer's statement that no -off site drainage will enter the site is not supported by contours shown
on the plan and cannot be accepted without that documentation.
15. The Wet Detention Basin Supplement form contains many inaccurate entries. We cannot tell which
average depth method was used. We see no information on how the average depth was calculated, We
believe that it is closer to 1.6 feet than the 3 feet that was entered. The elevations entered are not
consistent with other information in the plan and do not allow the spreadsheet to perform the calculations
as designed. For example, the distance from the bottom of the shelf and the top of sediment was calculated
by the program to be 2.0' based on the information entered and your engineer's plan sectional drawing on
sheet 5 of 9 shows 3'. Also, elevations from the stage storage data are not consistent with the information
entered into the wet detention basin supplement.
16. On page 7 of your engineer's response, he states that the two forebays have a volume of 19.8% of the total
volume but his Supplement Sheet shows a 21.800% value. Please correct this inconsistency.
17. The "Pond Sizing Calculations" of the final page of the October 28, 2014 letter provide some information
relative to the Stage- Storage Volume Calculation as shown in Table 3 -7 of the NC Stormwater BMP
Manual. However, the formatting on the table is confusing: some numbers need correction and the
incremental and cumulative volumes are not presented. Please provide that information in an
understandable format similar to the one shown m "Table 3 -7" in our Stormwater Manual. Also, the
calculations rely on an I 1 acre DA (drainage area) but we believe that the 7.5 acre figure is closer to the
actual size of that area.

Angelo Accenum
DWRN 13 -1070
Page 5 d5
18. The engineer states in his October 28, 2014 response to item #5 "Do not know where the criteria differs
between the plans and the design manual." Our staff has pointed to several areas where the plans were not
consistent with the rules and the Manual: some have been addressed and some have not. For example, the
original submittal did not include a vegetated filter strip after the pond. Furthermore, our staff have
repeatedly pointed out that we need engineering specifications to show that there would be no erosive flow
across the buffer. The requirements for a vegetated buffer strip are in the rules but that information has yet
to be provided. Your engineers' photographs and general statement about not seeing any erosion thus far
do not qualify as engineering specifications for a BMP.
19. The information on the single family portion of the project, sheet 1 of 9 needs to be revised to accurately
reflect only the multifamily portion of the development where the stormwater is to be treated. The
irrelevant numbers on the cover sheet have added considerable uncertainty and delay to our review of your
project.
20. More improvements in the clarity and accuracy of the design specifics of the plan are necessary. The field
engineer needs to be able to implement the provisions of the approved stormwater plans by looking at the
drawings and using what additional engineering specifications are provided. Enlarged drawings of the
discharge structure with dimensions are needed along with specific dimensions of the pond and forebays.
Pursuant to Title 15A NCAC 02H .0507(e), the Division is unable to approve your application. For the
reasons listed above, your application is hereby returned. Once you have addressed the problems and/or
inadequacies with your application as it was submitted, you will need to reapply to the Division for approval
including a complete application package and the appropriate fee. We will be happy to meet with you and/or your
engineer of record to work on a way to get the stormwater management plan approved.
Please be aware that you have no authorization under Section 401 of the Clear Water Act for this activity and any
work done within waters of the state would be a violation of North Carolina General Statutes and Administrative
Code.
Please contact Tim Fox. at 828 - 296 -4664 or tim.foancdenr gov if you have any questions or concerns.
Sincerely,
<
G. Landon Davidson, P.G., Regional Supervisor
Water Quality Regional Operations
Asheville Regional Office
cc: DWR ARO 401 files
cc: Boyd Devane —NCDWR
Tasha Alexander — USACE Asheville Regulatory Field Office
John V ilas — McGill Associates
David F Ramsey, P.E.
Andrea Leslie —NCWRC
Laura Herbert - DEMLR
Cheryl Buchanan — Town of Banner Elk
G:\WR \WQ\AvnUW01s \Non- D0T\Elk Creek .@ Banner Elk\ RTN. 401EIkaeekaBannerElkl2- 30- 14.d..