SW4070701_SW Report_20200227

STORMWATER MANAGEMENT PLAN
ECHOTA PHASE IV
WATAUGA CO., NORTH CAROLINA
REVISED CALCULATIONS - FEBRUARY 27, 2020
CHRISTINE BROWN CPSWQ, CPESC
J. MELISKI, PE
\I'llllllllI,',,
0l //�'%
Digitally signed ' C)°pFDiv
Joseph by JosephMelis
Meliski, Dateki,PE = o1.
SEAL _
P E 2020.0217 o
029887 a
16:38:17-05'00' � Ci °, f ( -
a000
I IPA
Cgill
55 Broad Street
Asheville, North Carolina 28801
828-252-0575
Firm License No.: C-0459
February 27, 2020

The Summit at Echota
Echota IV
September 20, 2019
PROPOSED DEVELOPMENT
ECHOTA IV
THE SUMMIT AT ECHOTA
NARRATIVE
PROJECT DESCRIPTION
The proposed project consists of the construction of roads, parking areas and buildings for
condominium units. It also includes a clubhouse/pool area. This submission is for Phase IV of
the Echota Development located off Hwy 105 in Watauga County. The project is located in a
High Quality Water (HQW) designated area. The project is defined as a Low Density
Development (12% built -upon area). Drainage and erosion control measures shall be designed
for a 25-yr. storm event. Development at full build -out is included in the calculations for this
State Stormwater Permitting submission. Echota IV is located off the north end of Chalakee
Trail Road of Phase III Echota Development in Watauga County.
SITE DESCRIPTION
The majority of the site is presently wooded and undeveloped. A portion along the ridge has
been used as a tree farm with areas cleared. The majority of the project development will be
located on the ridge. The stormwater drainage south and east of the ridge drains to the Watauga
River (located off the property). The Watauga River is classified B, Trout and High Quality
Water as designated by NC Department of Environment and Natural Resources. North of the
ridge the property drains to a named stream, Big Branch, class C. This stream drains to the
Watauga River. The project is in the Watauga River Basin. Existing cross slopes off the ridge
range from 25% to 45%. The proposed drainage patterns will remain similar to the existing.
The surface waters are located off the property.
ADJACENT PROPERTY
Land use in the vicinity is mainly residential development. Most of the nearby development is
the previously built phases of the Echota Development. There are other single-family residences
located nearby. Some areas, mainly to the north, are undeveloped or are rural residential
properties. Highway 105 lies to the south.
SOILS
The soil is described as Ashe-Chestnut complex 15% to 30% slopes. This is a gravelly fine
sandy loam with a Unified Soil Classification of SM. The soil has a soil erodible factor, K, of
0.10. This is a low erodible factor and the soil should not have any significant erosion problems.
The soil is in the Hydrology Group B.

The Summit at Echota
Echota IV
September 20, 2019
STORMWATER MANAGEMENT
Echota IV development is a continuation of the Echota 1, I1, and III development. The
development is considered Low -Density and there is a current State Stormwater Permit in place.
This project adds 7.646 acres of impervious area. With the addition of the project parcel area the
total Echota Development is 344.92 acres.
Stormwater will be collected by vegetated swales and minimal pipe systems to bring the drainage
beyond the constructed slopes. Curb -cuts will be used to outlet stormwater along the roadway.
Pipes will outlet to rip -rap dissipators, which will reduce out flow velocities and disperse flow,
no outflows are located near stream buffers. Conveyances are designed for the 25-year storm
event. The grassed swales will contribute to reducing peak flow by allowing infiltration to occur
and aid in reducing pollutants. Design considerations were used to help minimize the amount of
impervious area on site. Minimum parking at the clubhouse area and the incorporation of lawn
areas helped to keep the amount of impervious area low at the recreational area.
STORMWATER MAINTENANCE
Roads, swales and storm pipes shall be maintained by the Developer. They shall be checked and
maintained on a regular basis. Repairs and or replacements shall be made as deemed necessary
to assure proper performance of the stormwater features. Grassed swales will be inspected once
a quarter and records of operation and maintenance will be kept at a known location and made
available upon request.

The Summit at Echota
Echota IV
September 20, 2019
CALCULATIONS

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Table 8.04e
Modifying Value for
Roughness Coefficient Due
to Vegetation In the Channel
N C_ if-_ -+- S
Vegetation and Flow Conditions Range in Modifying Value
Comparable to:
Low Effect 0.005 to 0.010
Dense growths of flexible turf grass or
weeds, such as Bermudagrass and
Kentucky bluegrass. Average depth of
flow 2 to 3 times the height of the vegeta-
tion
Medium Effect 0.010 to 0.025
Turf grasses where the average depth
of flow is 1 to 2 times the height of
vegetation
Stemmy grasses, weeds or tree seed-
lings with moderate cover where the
average depth of flow is 2 to 3 times the
height of vegetation
Brushy growths, moderately dense, sim-
ilar to willows 1 to 2 years old, dormant
season, along side slopes of channel
with no significant vegetation along the
channel bottom, where the hydraulic ra-
dius is greater than 2 ft
High Effect 0.025 to 0.050
Grasses where the average depth of
flow is about equal to the height of veg- Us �e 0 O • ���
etation
Dormant season, willow or cottonwood
trees 8 - 10 years old, intergrown with
some weeds and brush; hydraulic radius
2to4ft
1-yr old, intergrown with some weeds in
full foliage along side slopes; no sig-
nificant vegetation along channel bot-
tom; hydraulic radius 2 to 4 ft
Grasses where average depth of flow is
less than one-half the height of vegeta-
tion
Very High Effect 0.050 to 0.100
Growing season, bushy willows about 1-
yr old, intergrown with weeds in full fol-
iage along side slopes; dense growth of
cattails or similar rooted vegetation
along channel bottom; hydraulic radius
greater than 4 ft
Growing season, trees intergrown with
weeds and brush, all in full foliage; hy-
draulic radius greater than 4 ft
8,04.4

• N� C_ E S
OJ
Table 8.05a
Maximum Allowable Design Velocities1
for Vegetated Channels
Typical Soil
Grass Lining
Permissible Velocity
Channel Slope Characteristicsz
for Established Grass
Application
Lining (ft/sec)
0-5% Easily Erodible
Bermudagrass
5.0
Non -plastic
Tall fescue
4.5
(Sands & Silts)
Bahiagrass
4.5
Kentucky bluegrass
4.5
Grass -legume mixture
3.5
Erosion Resistant
Bermudagrass
6.0
Plastic
Tall fescue
5.5
(Clay mixes)
Bahiagrass
5.5
Kentucky bluegrass
5.5
Grass -legume mixture
4.5
5-10% Easily Erodible
Bermudagrass
4.5
Non -plastic
Tall fescue
4.0
(Sands & Silts)
Bahiagrass
4.0
Kentucky bluegrass
4.0
Grass -legume mixture
3.0
Erosion Resistant
Bermudagrass
5.5
Plastic
Tall fescue
5.0
(Clay Mixes)
Bahiagrass
5.0_,_er
Kentucky bluegrass
"" 5A ,,._
Grass -legume mixture
1,!
>10% Easily Erodible
Bermudagrass
3.5
Non -plastic
Tall fescue
2.5
(Sands & Silts)
Bahiagrass
2.5
Kentucky bluegrass
2.5
Erosion Resistant
Bermudagrass
4.5
Plastic
Tall fescue
3.5
(Clay Mixes)
Bahiagrass
3.5
Kentucky bluegrass
Source: USDA-SCS Modified
NOTE: 'Permissible Velocity based on 10-yr storm peak
runoff
2Soil erodibility based on resistance to soil movement from concentrated flowing water.
3Before grass is established, permissible velocity is determined by the type of temporary liner used.
Selecting Channel To calculate the required size of an open channel, assume the design flow is
uniform and does not vary with time. Since actual flow conditions change
Cross -Section throughout the length of a channel, subdivide the channel into design reaches,
Geometry and design each reach to carry the appropriate capacity.
The three most commonly used channel cross -sections are "W-shaped, par-
abolic, and trapezoidal. Figure 8.05b gives mathematical formulas for the area,
hydraulic radius and top width of each of these shapes.
8.05.4

Table 8.05f Manning's Roughness Coefficient
Lining Category
Lining Type
n-value
n value for Depth Ranges
0-0.5 ft 0.5-2.0 ft
0-15 cm) 15-60 cm)
2.0 ft
(> 60 cm)
Rigid
Concrete
0.015
0.013
0.013
Grouted Riprap
0.040
0,030
0.028
Stone Masonry
0.042
0.032
0.030
Soil Cement
0.025
0.022
0.020
Asphalt
0.018
0.016
0.016
Unlined
Bare Soil
0.023
0.020
0.020
Rock Cut
0.045
0.035
0.025
Gravel Riprap
1-inch (2.5-cm) D50
0.044
0.033
0.030
2-inch (5-cm) D5o
0.066
0.041
0.034
Rock Riprap
6-inch (15-cm) D50
(0.104
0 069
l.-'--
0.035
12-inch (30-cm) D5o
-
i 1 0.078 �__..,•
0.040
Note: Values listed are representative values for the respective depth ranges: Mariiiing's roughness coefficient , n, vary with the flow depth.
rk t , ; - 13 1�z ► 0-- 6z l�l'
A-0 DETERMINING SHEAR STRESS
Shear stress, T, at normal depth is computed for the lining by the following
equation:
T = yds
Td = Permissible shear stress
where:
T = shear stress in lb/ft2
y = unit weight of water, 62.4 lb/ft3
d = flow depth in ft
s = channel gradient in ft/ft.
If the permissible shear stress, Td, given in Table 8.05g is greater than the
computed shear stress, the riprap or temporary lining is considered acceptable.
If a lining is unacceptable, select a lining with a higher permissible shear stress
and repeat the calculations for normal depth and shear stress. In some cases it
may be necessary to alter channel dimensions to reduce the shear stress.
Computing tractive force around a channel bend requires special considerations
because the change in flow direction imposes higher shear stress on the channel
bottom and banks. The maximum shear stress in a bend, Tb, is given by the
following equation:
Tb = KbT
where:
Tb = bend shear stress in lb/ft2
Kb = bend factor
T = computed stress for straight channel in lb/ft2
The value of Kb is related to the radius of curvature of the channel at its center
line, Rc, and the bottom width of the channel, B, Figure 8.05e. The length of
channel requiring protection downstream from a bend, Lp, is a function of the
roughness of the lining material and the hydraulic radius as shown in Figure
8.05 f.
8.05.12
Rev. 12193

11-� .c. L- w (-:-i:l (-111�--I--t-1 �
Appendices
Table 8.05g
Permissible. Shear Stresses
for Riprap and Temporary
Liners
Cv C-5�-
Sc.-ISM" arr
C � � "-C) If
. C;-
Permissible Unit Shear Stress, Td
Lining Category
Lining Type
(lb/ft)
Temporary
Woven Paper Net
0.15
Jute Net
0.45
Fiberglass Roving:
Single
0.60
Double
0.85
Straw with Net
1.45
Curled Wood mat
1.55
Synthetic Mat
2.00
d5o Stone Size (inches)
Gravel Riprap
1
0.33
2
0.67
Rock Riprap
Szco�9.--
6
----------
2.00
__.-3.0Q�
9
12
1
15
5.00
18
6.00
21
7.80
24
8.00
Adapted From: FHWA, i-IFC-15, April 1983, pgs. 17 & 37.
Design Procedure- The following is a step-by-step procedure for designing a temporary liner for a
Temporary Liners channel. Because temporary liners have a short period of service, the design Q
may be. reduced. For liners that are needed for six months or less, the 2-yr
frequency stone is recommended.
Step 1. Select a liner material suitable for site conditions and application.
Determine roughness coefficient from manufacturer's specifications or Table
8.05e, pg. 8.05.10.
Step 2. Calculate the normal flow depth using Manning's equation (Figure
8.05d). Check to see that depth is consistent with that assumed for selection of
Manning's n in Figure 8.05d, pg. 8.05.11. For smaller runoffs Figure 8.05d is
not as clearly defined. Recommended solutions can be determined by using the
Manning equation.
Step 3. Calculate shear stress at normal depth.
Step 4. Compare computed shear stress with the pen-nissible shear stress for
the liner.
Step 5. If computed shear is greater than permissible shear, adjust channel
dimensions to reduce shear or select a more resistant lining and repeat steps 1
through 4.
Design of a channel with temporary lining is illustrated in Sample Problem
8.05b, pg. 8,05,14.
8.05.13

The Summit at Echota
Echota IV
September 20, 2019
APPENDIX

Watauga County, NC
Page 1 of 2
PARI D: 1889538255000
ECHOTA EAST RIDGE LLC,
Parcel
ParlD
Tax Year
SITUS Addess
City, State, Zip
Unit #
Unit Description
NBHD
Class
Land Use Code
Living Units
CAMA Acres
Zoning
Map #
Jan 1 Values
Land Value. 104,200
Building Value 0
--------------------------
--------------------------
Appraisal Total 104,200
Exemptions or Exclusions 0
Land Deferred Value
Taxable Total 104,200
Owner Mailing
Tax Year
Sequence Number
Owner Number
Owner
Mailing Address
City, State, Zip
Legal Description
2019
0
1625141
ECHOTA EAST RIDGE LLC
151 MR BISH BLVD
BOONE NC 28607-7842
Township
15 - WATAUGA
City Code
Jurisdiction (Tax Code District)
F01 - FOSCOE
Unit Desc
Unit #
Book
Page
Legal Desc 1
T-1 P022/196
Deeded Acres
7.42
httD://tax.watgov.org/WataugaNC/Datalets/PrintDatalet.asnx?pin=19995392___ 10/4/2019

Watauga County, NC
Page 2 of 2
Sale Date Book Page Sale Price Grantor Grantee
30-MAY-19 2030 299
08-MAY-19 2026 527 0 ECHOTA EAST RIDGE LLC THE SUMMIT AT ECHOTA, LLC
06-AUG-10 1523 409 125,000 TOWNSEND, WILLIAM RALPH ECHOTA EAST RIDGE LLC
06-AUG-10 022 196 TOWNSEND, WILLIAM RALPH ECHOTA EAST RIDGE LLC
http://tax.watgov. org/WataugaNC/Datalets/PrintDatalet.aspx?pin=188953 82... 10/4/2019

Watauga County, NC
Page 1 of 2
PARI D: 1889644065000
PRC FAMILY LTD PTNRP,
Parcel
ParlD
Tax Year
SITUS Addess
City, State, Zip
Unit #
Unit Description
NBHD
Class
Land Use Code
Living Units
CAMA Acres
Zoning
Map #
Jan 1 Values
Land Value. 12,600
Building Value 0
--------------------------
--------------------------
Appraisal Total 12,600
Exemptions or Exclusions 0
Land Deferred Value 350,500
Taxable Total 12,600
Owner Mailing
Tax Year
Sequence Number
Owner Number
Owner
Mailing Address
City, State, Zip
Legal Description
Township
City Code
Jurisdiction (Tax Code District)
Unit Desc
Unit #
Book
Page
Legal Desc 1
Deeded Acres
2019
0
1622510
PRC FAMILY LTD PTNRP
132 CLARK CIRCLE
BOONE NC 28607
15 - WATAUGA
F01 - FOSCOE
1248
424
PROPERTY ON HWY 105
46.73
132 CLARK CIR
http://tax.watgov.org/WataugaNC/Datalets/PrintDatalet.aspx?pin= l 8896440... 10/4/2019

Watauga County, NC Page 2 of 2
Sale Date Book Page Sale Price Grantor Grantee
30-MAY-19 2030 299
08-MAY-19 2026 516 2,880,000 PRC FAMILY LTD PTNRP THE SUMMIT AT ECHOTA, LLC
28-DEC-06 1248 424 0
http://tax.watgov.org/WataugaNC/Datalets/PrintDatalet.aspx?pin=18896440... 10/4/2019

Precipitation Frequency Data Server
Page 1 of 4
NOAA Atlas 14, Volume 2, Version 3
Location name: Boone, North Carolina,
' USA*
Latitude: 36.21670, Longitude:-81.66670
Elevation: 3213.64 ft**
source: ESRI Maps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
AMS-based point precipitation frequency estimates with 90% confidence intervals (in
inches/hour)'
Duration
Annual exceedance probability (1/years)
1 /2
1/5
1 /10
1 /25
1 /50
1/100
1 /200
1 /500
1 /1000
5-min
5.27
6.50
7.36
8.45
9.26
10.1
11.1
12.3
13.4
(4.86-5.75)
1 (5.98-7.10)
1 (6.73-8.04)
1 (7.64-9.26)
1 (8.28-10.2)
1 (8.93-11.3)
1 (9.54-12.5)
1 (10.3-14.1)
1 (11.0-15.5
10-min
4.21
(3.89-4.60)
6.21
(4.79-5.69)
5.89
(5.39-6.43)
6.73
(6.09-7.39)
7.39
(6.59-8.15)
8.06
(7.09-8.97)
8.77
(7.57-9.88)
9.74
(8.18-11.2)
10.5 )
(8.65-12.2
15-min
3.53
4.39
4.96
5.69
6.24
6.80
7.38
8.18
8.83
(3.26-3.86)
1 (4.04-4.80)
1 (4.54-5.42)
(5.14-6.24)
(5.56-6.88)
(5.98-7.56)
(6.37-8.31)
(6.87-9.36)
1 (7.24-10.2)
2.44
3.12
3.60
4.21
4.70
5.20
5.74
30-min
(2 .25-2.66)
(2.87-3.41)
(3.29-3.93)
(3.81-4.62)
(4.19-5.18)
(4.57-5.79)
(4.96-6.47)
(5.47-7.45)
(5.86-8.30
1.53
2.00
2.34
2.81
3.18
3.58
4.03
4.67
SIT-]
60-min
(1.41-1.67)
1.84-2.19
(2.14-2.56)
(2.54-3.08)
(2.84-3.51)
(3.15-3.99)
(3.48-4.54)
(3.92-5.34)
1 (4.28-6.06)
0.924
1.22
1.44
1.75
2.01
2.29
2.61
3.09
3.53
2-hr
(0 .848-1.00)
1 (1.12-1.33)
1 (1.31-1.56)
1 (1.57-1.91)
1 (1.78-2.20)
1 (2.00-2.54)
1 (2.23-2.93)
1 (2.57-3.53)
1 (2.87-4.08)
0.671
0.885
1.04
1.27
1.46
1.68
1.92
2.29
2.62
3-hr
(0.618-0.734)
(0.813-0.968)
(0.952-1.14)
(1.14-1.40)
(1.30-1.62)
(1.46-1.87)
(1.64-2.17)
(1.90-2.64)
(2.12-3.06)
0.441
0.577
0.675
0.814
0.930
1.06
1.20
2 1.4
1.61
6-hr
(o .408-0.481)
(0.531-0.629)
(0.618-0.737)
(0.738-0.895)
(0.832-1.03)
(0.931-1.18)
(1.04-1.36)
(1.19-1.63)
(1.33-1.89)
0.290
0.376
0.434
0.511
0.573
0.638
0.710
0.816
0.912
12-hr
(0.268-0.314)1(0.346-0.408)
(0.398-0.472)
(0.466-0.560)
(0.516-0.632)
(0.568-0.711)
(0.622-0.799)
(0.700-0.933)1(0.769-1.06)
0
0.231
0.275
0.338
090
046
0.507
0.598
0.675
24-hr
.170
(0 .157-0.186)
(0.212-0.253)
(0.252-0.302)
(0.307-0.372)
.3
(0.350-0.430)
.4
(0.396-0.496)
(0.444-0.569)
(0.512-0.678)
(0.568-0.774)
0.102
0.138
0.164
0.202
0.233
0.268
0.305
0.362
0.410
2-day
(0.094-0.111)
(0.127-0.150)
(0.151-0.180)
(0.183-0.221)
(0.209-0.257)
(0.237-0.297)
(0.266-0.341)
(0.308-0.410)
(0.341-0.471)
0.073
0.097
0.115
0.141
0.161
0.184
0.208
0.244
0.276
3-day
(0.067-0.079)
(0.090-0.106)
(0.106-0.126)
(0.128-0.153)
(0.146-0.177)
(0.164-0.203)
(0.183-0.232)
(0.210-0.276)
(0.232-0.315)
0.058
0.077
0.091
0.110
0.125
0.142
0.160
0.186
0.209
4-day
(0.054-0.063)
(0.071-0.083)
(0.084-0.099)
(0.101-0.119)
(0.114-0.137)
(0.127-0.156)
(0.141-0.177)
(0.161-0.208)
(0.178-0.237)
0.038
0.049
0.058
0.069
0.078
0.087
0.098
0.112
0.124
7-day
(0.035-0.040)
(0.046-0.053)
(0.054-0.062)
(0.064-0.074)
(0.071-0.085)
(0.079-0.096)
(0.087-0.108)
(0.098-0.125)
(0.107-0.140)
0.030
0.038
0.044
0.052
0.058
0.064
0.070
0.079
0.087
10-day
(0.028-0.032)
(0.036-0.041)
(0.041-0.047)
(0.048-0.055)
(0.053-0.062)
(0.058-0.069)
(0.063-0.076)
(0.070-0.088)
(0.076-0.099)
0.020
0.025
0.029
0.033
0.037
0.040
0.044
0.050
0. 554
20-day
(0.019-0 021)
(0.024-0.026)
(0.027-0.030)
(0.031-0.035)
(0.034-0.039)
(0.037-0.044)
(0.040-0.048)
(0.045-0.054)
(0.048-0.059)
0.016
0.020
0.023
0.026
0.029
0.031
0.034
0.037
0.040
30-day
(0.015-0017)
(0.019-0.021)
(0.021-0.024)
(0.025-0.028)
(0.027-0.031)
(0.029-0.034)
(0.031-0.037)
(0.034-0.041)
(0.036-0.044)
0.013
0.017
0.019
0.021
0.023
0.025
0.027
0.029
0.031
45-day
(0.013-0.014)
(0.016-0.017)
(0.017-0.020)
(0.020-0.022)
(0.021-0.024)
(0.023-0.026)
0.024-0.029)
(0.026-0.032)
(0.028-0.034)
0.012
0.015
0.016
0.018
0.020
0.021
6.022
0.024
0.026
60-day
(0.011-0013)
(0.014-0.015)
(0.015-0.017)
(0.017-0.019)
(0.019-0.021)
(0.020-0.022)
(0.021-0.024)
(0.022-0.026)
(0.023-0.028)
Precipitation frequency (PF) estimates in this table are based on frequency analysis of annual maxima series (AMS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation
frequency estimates (for a given duration and annual exceedance probability) will be greater than the upper bound (or less than the lower
bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than
currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
https://hdsc.nws.noaa.gov/hdsc/pfds/pfds printpage.htm1?1at=36.2167&1on... 10/17/2019

- --o- - --
NOAA Atlas 14, Volume 2, Version 3
BOONE
Station ID: 31-0977
Location name: Boone, North Carolina,,
USA*
Latitude: 36.21670, Longitude:-81.6667*
Elevation: 'A., .�
Elevation (station metadata): 3241 ft**
* source: ESRI Maps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
AMS-based point precipitation frequency estimates with 90% confidence intervals (in
inches)'
Annual exceedance probability (1/years)
1 /2
1l5
1 /10
1 /25
1 /50
1/100
1 /200
1 /500
1 /1000
0.439
0.542
0.613
0.704
0.772
0.845
0.922
1.03
1.12
5-min
(D .405-0.479)
(0.498-0.592)
(0.561-0.670
(0.637-0.772)
(0.690-0.853)
0.744-0.941)
(0.795-1.04)
(0.862-1.18)
(0.916-1.30)
0.701
0.868
0.981
1.12
1.23
1.34
1.46
1.62
1.76
10-min
(D.648-0.767)
(0.798-0.948)
(0.898-1.07)
1 (1.01-1.23)
1 (1.10-1.36)
1 (1.18-1.50)
(1.26-1.65)
(1.36-1.86)
(1.44-2.04)
0.882
1.10
1.24
1.42
1.56
1.70
1.84
2.04
2.21
15-min
(D.814-0.964)
(1.01-1.20)
1 (1.14-1.36)
1 (1.29-1.56)
1 (1.39-1.72) 11
(1.49-1.89)
(1.59-2.08)
(1.72-2.34)
(1.81-2.56)
1.22
1.56
1.80
2.11
2.35
2.60
2.87
3.25
3.57
30-min
(1.13-1.33)
(1.44-1.70)
(1.65-1.96)
(1.91-2.31)
(2.10-2.59)
(2.29-2.90)
(2.48-3.23)
(2.73-3.72)
(2.93-4.15 )
1.53
2.002.B1
3.18
3.58
4.03
4.67
5.22
60-min
1.41-1.67)
(1.84-2.19)
(2.14-2.56)
1(2.54-3.08)
(2.84-3.51)
3.15-3.99)
(3.48-4.54)1(3.92-5.34)
(4.28-6.06)
1.85
2.44
2.88
3.50
4.01
4.58
5.22
6.19
7.05
2-hr
(1.70-2.01)
(2.24-2.66)
(2.62-3.13)
(3.15-3.82)
(3.564.41)
(4.00-5.08)
(4.47-5.85)
(5.15-7.06)(
5.73-8.17)
2.01
2.66
3.13
3.82
4.39
5.03
5.76
-
7.86
3-hr
(1.86-2.20)
(2.44-2.91)
(2.86-3.43)
(3.44-4.20)
(3.90-4.87)
(4.39-5.63 )
( 4.93-6.52)
(5.69-7.92)
(6.37-9.20)
2.64
3.45
4.04
4.87
5.57
6.33
7.18
8.47
9.65
6-hr
(2.44-2.88)
(3.18-3.77)
(3.70-4.41)
(4.42-5.36)
1 (4.98-6.16)
1 (5.58-7.08)
(6.22-8.14)
(7.149.78)
(7.94-11.3)
3.49
4.53
5.23
6.16
6.90
7.69
8.55
9.83
11.0
12-hr
(3.23-3.78)
(4.17-4.92)
(4.80-5.69)
(5.61-6.75)
(6.22-7.61)
(6.84-8.56)
(7.50-9.63)
(8.43-11.2)
( 9.26-12.7)
4.08
5.54
6.61
8.11
9.35
10.7
12.2
14.3
16.2
24-hr
(3.77-4.47)
(5.09-6.07)
(6.05-7.25)
(7.36-8.92)
(8.40-10.3) 11
(9.49-11.9)
(10.7-13.6)
(12.3-16.3)
(13.6-18.6)
4.90
6.61
7.88
9.69
11.2
12.8
14.7
17.4
19.7
2-day
(4.52-5.34)
(6.08-7.22)
(7.23-8.62)
(8.81-10.6)
(10.1-12.3)
1 (11.4-14.2)
(12.8-16.4)
( 14.8-19.7)
(16.4-22.6)
5.24
7.00
8.31
10.1
11.6
13.2
15.0
17.6
19.9
3-day
(4.86-5.69)
(6.47-7.62)
(7.64-9.04)
(9.23-11.0)
(10.5-12.7)
1 (11.8-14.6)
(13.2-16.7)
(15.1-19.9)
(16.7-22.7)
5.58
7.40
8.73
10.6
12.0
13.6
15.3
17.8
20.1
4-day
(5.19-6.04)
(6.85-8.01)
(8.05-9.46)
(9.66-11.5)
(10.9-13.1)
(12.2-15.0)
(13.6-17.0)
(15.5-20.0 )
( 17.1-22.8 )
6.34
8.29
9.69
1 _1
13.1
14.7
16.4
18.8
20.9
7-day
(5.94-6.80)
(7.73-8.91)
(9.00-10.4)
(10.7-12.5)
1 (12.0-14.2) 11
(13.3-16.1)
1(147-18.1)
(16.5-21.0)
(18.0-23.6)
7.19
9.22
10.6
12.4
13.9
15.3
16.8
18.9
20.9
10-day
(6 .75-7.66)
(8.64-9.83)
(9.93-11.3)
(11.6-13.3)
1 (12.8-14.9) 11
(14.0-16.5)
(15.2-18.3)
(16.9-21.2)
( 18.3-23.8)
9.51
12.0
13.7
15.9
17.7
19.4
21.3
23.8
25.8
20-day
(9.00-10.1)
(11.3-12.7)
(12.9-14.5)
(14.9-16.9)
1 (16.4-18.9)
1 (17.9-20.9)
(19.4-23.0)
(21.4-26.0)
(22.9-28.5)
11.6
14.5
16.5
18.9
20.7
22.6
24.4
26.9
28.9
30-day
(11.0-12.3)
(13.7-15.4)
(15.5-17.5)
(17.7-20.1)
1 (19.3-22.1)
1 (20.8-24.2)
(22.3-26.4)
(24.3-29.3)
(25.8-31.7)
14.6
17.8
20.0
22.7
24.7
26.7
28.7
31.4
33.4
45-day
(13.8-15.4)
1 (16.9-18.9)
18.9-21.2)
(21.3-24.1)
1 (23.1-26.3)
1 (24.8-28.6)
(26.4-30.9)
(28.5-34.1)
(30.0-36.5)
17.3
21.0
23.4
26.3
28.4
30.4
32.4
34.9
36.8
60-day
(16 5-18.2)
(2o.0-22.2)
2.2-24)
(2 .74.8-27.8)
(2
(26.7-30.0)
(28.4-32.3)
(30.1-34.6 )
( 32.2-37.6)
(33.7-40.0)
' Precipitation frequency (PF) estimates in this table are based on frequency analysis of annual maxima series (AMS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation
frequency estimates (for a given duration and annual exceedance probability) will be greater than the upper bound (or less than the lower
bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than
currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
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Soil Map —Watauga County, North Carolina
The Summit at Echota, LLC Phase I
Map Unit Legend
Map Unit Symbol
Map Unit Name
Acres in AO1
Percent of AOI
AcD
Ashe-Chestnut complex, 15 to
30 percent slopes, very
10.6
35.7%
rocky
AcE
8.41
28.2%
Ashe-Chestnut complex,
escarpment, 30 to 50
j
- - -._.. ----- -
percent slopes, very rocky
-- .......... .
AcF
31.8%
Ashe-Chestnut complex,
escarpment, 50 to 95
9.4
percent slopes, very rocky
CsE
Cullasaja very cobbly loam, 30
1.3
4.2% i
to 50 percent slopes, very
stony
Totals for Area of Interest
29.7
100.0%
USDA Natural Resources Web Soil Survey 5/31/2019
Conservation Service National Cooperative Soil Survey Page 3 of 3

Soil Map —Watauga County, North Carolina
(The Summit at Echols, LLC Phase q
MAP LEGEND
MAP INFORMATION
Area of Interest (AOI)Q
Spoil Area
The soil surveys that comprise your A01 were mapped at
Area or Interest (AOI)
A( Stony Spot
y
1:12,000.
Solis
U
Ball Map Unit Polygons
CB very stony spot
Warning: Soil Map may not be valid at this scale.
Wet Spot
Enlargement of maps beyond the scale of mapping can cause
'-10
soil Map Unit Llnas
misunderstanding of the detail of mapping and accuracy of soil
®
Boll Map Unit Points
L1 other
line placement. The maps do not show the smell areas of
Special Line Features
contrasting soils that could have been shown at a more detailed
Special
Point Features
scale.
u
Blowout
Water Features
Borrow Ph
Streams and Canals
`"�
Please rely on the bar scale on each map sheet for map
Transportation
measurements.
Clay spot
+-r-t Rolls
Source of Map; Natural Resources Conservation Service
Closed Depression
Interstate Highways
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Gravel Pit
a US Routes
Maps from the Web Soil Survey are based on the Web Mercator
„
Gravelly spot
Major Roads
projection, which preserves direction and shape but distorts
Landfill
distance and area. A projection that preserves area, such as the
_ Local Roads
Albers equal-area conic projection, should be used if more
A.
Lava Flow
Background
accurate calculations of distance or area are required.
I,,
Marsh or swamp
® Aerial Photography
This product Is generated from the USDA-NRCS certified data as
Mine or quarry
of the version date(s) listed below.
$(�
Miscellaneous Water
Sol] Survey Area: Watauga County, North Carolina
Survey Area Dala: Version 17, Sep 10, 2018
0
Perennial Water
Soil map units are labeled (as space allows) for map scales
•vr
Rock Outcrop
1:50,000 or larger.
.nl..
saline Spot
Date(s) aerial Images were photographed: May 20, 2011—Nov
9, 2017
Sandy Spot
The orthopholo or other base map on which the soil lines were
1�P
severely Eroded Spot
compiled and digitized probably differs from the background
0
Sinkhole
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Slide or Slip
Sock: spot
115D,% Natural Resources Web Soil Survey 5/31/2019
Conservation Service National Cooperative Soil Survey Page 2 of 3