NC0026646_Instream Assessment_19870629

NPDES DOCUMENT SCANNING COVER SHEET
NPDES Permit:
NC0026646
Pilot Mountain WWTP
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Owner Name Change
(Istrearn
Assessment (67b
Speculative Limits
Environmental Assessment (EA)
Document Date:
June 29, 1987
This document printed on reuse paper - ignore any
content on the re -worse snide

DIVISION OF ENVIRONMENTAI. MANAGEMENT
June 29, 1987
MEMORANDUM
TO: Steve Mauney
FROM: Steve Zoufaly
THRU: Trevor Clements
Steve Tedder
SUBJECT: In -Stream Assessment
Town of Pilot Mountain WWTP
Surry County
SOC No. EMC WQ 86-19 Ad
The Town of Pilot Mountain in Surry County is requesting a modification of
their interim BOD and TSS limits for their current SOC, which expires June 30, 1988.
The Town's WWTP discharges into Heatherly Creek, (Class C, 7Q10 = 0.15 cfs), which
is located in the Yadkin River Basin. s
The facility had been issued an SOC, effective March 13, 1987, for limits of
30 mg/1 BOD5, 14 mg/1 NH3N, and 5 mg/1 D.O. at an increase in wasteflow of 0.09 MGD
of domestic wastewater. The permit limits have not been complied with for the
months of February through April, 1987. Therefore, a modification has been
requested in order that the facility may meet less stringent BOD and TSS limits.
A level B analysis was completed using wasteflows of 0.657 MGD and 0.747 MGD.
The Winston-Salem Regional Office suggested limits of 50 mg/1 BOD5, 14 mg/1 NH3N,
(no NH33N limit for the period of Nov. 1 - March 31), 5 mg/1 D.O., 50 mg/1 TSS,
1000/100 ml fecal coliform and 6-9 SU pH. Using these limits, BOD-ultimate was
calculated as: BOD = 1.5 (BODS) + 4.5 (NH,). The model does not predict a
significant impact on water quality in Heatherly Creek under the increased wasteflow
at the suggested limits for either the summer or winter periods.
The following is a summary of the results:
Summer Winter
0.657 0.747 MGD 0.657 0.747 MGD
D.O. minimum 5.18 5.13 6.16 6.06
D.O. sag point (miles below discharge) 0.2 0.2 0 0
# miles D.O. 5 mg/1 0 0 0 0
# miles D.O. = 0 0 0 0 0

The model summary data (summer/winter) is as follows:
D.A.:
76Y8
Temperature:
Slope:
Velocity:
Depth:
Kl @ 200C:
K2 @ 20 C:
If you have any
SZ:gh
cc: Kent Wiggins
Page Benton
1.22 mil
1.45 cfs
0.15 cfs
25°C/14°C
51.6 (average)
0.351 fps/0.42 fps (average)
0.49 ft/0.5 ft. (average)
0.78/0.85
32.65/39.04
questions, please let me know.

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'
A.
SUMMER
pre-soc
--- MODEL RESULTS
Discharger : PILOT MOUNTAIN WWTP SOC
Receiving Stream : HEATHERLY CREEK
The End D.O. is 7.41 mg/l.
The End CBOD is 11.97 mg/l.
The End NBOD is 0.00 mg/l.
DO Min
(mg/l)
Segment 1 5.18
Reach 1
Reach 2
Milepoint Reach #
_________
0.20 1
WLA WLA WLA
CBOD NEll OD DO Waste Flow
(mg/l) (mg/l) (mg/1) (mgd)
__________
138 0.00 5.00 0.65700
0 0.00 0.00 0.00000

*** MODEL SUMMARY DATA ***
Discharger PILOT MOUNTAIN WWTP SOC
Receiving Stream a HEATHERLY CREEK
Summer 7010 4 0.15
Design Temperature: 25.
Tubb isi.n u 030703
Stream Class: C
Winter 7010 a 0.38
ILENBTHI SLOPEI VELOCITY I DEPTHI KI I KI I K2 I K2 1 KN I KN I KNR I KNR
I mile 1 ft/mil fps 1 ft ldesignl 220* Idesignl i20° idesignl n0° Idesignl 320°
1 1 1 1 1 1 1 1 1 1 1 1
Segment 1 1 1.501 51.601 0.351 1 0.49 1 0.99 i 0.78 136.40 1 32.651 0.00 1 0.00 1 0.00 1 0.00
Reach i I 1 1 1 1 1 I I 1 1 1 1
1 I I I 1 1 I I 1 1 1 1
Segment 1 I 2.801 12.801 0.311 11.26 1 0.52 1 0.42 1 8.00 1 7.171 0.00 1 0.00 1 0.00 1 0.00
Reach 2 I 1 I l 1 1 1 1 1 1 1 1
I Flaw I CBOD 1 NBOD 1 D. O. 1
1 cfs 1 mg/I i mg/1 1 mg/1 1
Segment 1 Reach 1
Waste 1 1.018 1 138.000 1 0. t__i0 1 5.000
Headwaters i 0.150 1 2.000 1 0.000 1 7.440
Tributary 1 0.000 1 0.000 1 0,000 1 0„000
* Runoff 1 0.100 1 2.000 1 0.000 1 7.440
Segment 1 Reach 2
Waste 1 0.000 1 0.000 1 0.000 1 0.000
Tributary 1 5.630 1 2.00 0 1 0.000 1 7.440
* Runoff 1 0.340 1 2.000 1 0.000 1 7.440
0
* Runoff flaw is in cfs/mile

�
. ,
| Seg`#^} Reach # | 8eg Mi | D.O. \ CBOD | NBOD | Flow |
` 1 1 0.00 5.31 120"54 0.00 1"17
1 1 0.10 5.20 117.50 0.00 1.18
1 1 0.20 5.18 114.55 0.00 1.19
1 1 0.30 5.20 111.67 0.00 1.20
1 1 0.40 5.25 108.88 0.00 1.21
J. 1 0.50 5.81 106.17 0.00 1.22
1 1 0.60 5.38 103.53 0.00 1.23
1 1 0.70 5.44 100.96 0.00 1.24
1 1 0.80 5.51 98.47 0.00 1.25
1 1 0.90 5.58 96.04 0.00 1.26
1 1 1.00 5.64 93.67 0.00 1.27
1 1 1"10 5.71 91.38 0.00 1.28
1 1 1.20 5.77 89.14 0.00 1.29
1 1 1.30 5.83 86.96 0.00 1.30
1 1 1.40 5.89 84.85 0.00 1.81
1 1 1.50 5.95 82.79 0.00 1.82
1 2 1.50 7.16 17.33 0.00 6.95
1 2 1.70 7.16 16"83 0.00 7.02
1 2 1.90 7.16 16.35 0.00 7.08
1 2 2.10 7.18 15.88 0.00 7.15
1 2 2.30 7.20 15.43 0,00 7"22
1 2 2.50 7.22 15.00 0.00 7.29
1 2 2.70 7.24 14.57 0.00 7.36
1 2 2.90 7.27 14.16 0.00 7"42
1 2 8.10 7.29 13.77 0.00 7.49
1 B 3.30 7.31 18.39 0.00 7.56
1 2 3.50 7.34 13.01 0.00 7.68
1 2 3.70 7.36 12.65 0.00 7.70
1 2 3.90 7.39 12.81 0.00 7.76
1 2 4.10 7"41 11.97 0.00 7"83
\ Seg # | Reach # | Geg Ili | D.O. | CBOD | NBOD / Flow |

^
SUMMER
post soc
Discharger
Receiving Stream
~- MODEL RESULTS
o PILOT MOUNTAIN WWTP SOC
: HEATHERLY CREEK
The End D.O. is 7.32 mg/l.
The End CBOD is 18.19 mg/l.
The End NBOD is 0.00 mg/l"
WLA WLA WLA
DO Min CBOD NBOD DO Waste Flow
(mg/l) Milepoint Reach # (mg/l) (Mg/1) (mg/l) (mgd)
Segment 1 5.13 0"20 1
Reach 1 138 0.00 5.00 0.74700
Reach 2 0 0.00 0.00 0.00000

*** MODEL SUMMARY DATA ***
Discharger PILOT MOUNTAIN WWTP SOC Subbasin ; 030'703
Receiving Stream n HEATHERLY CREEK Stream Class: C
Summer 7G110 u 0.15 Winter 7010 a 0.38
Design Temperature: 25.
ILENGTHI SLOPE! VELOCITY 1 DEPTNI K1 I K1 I K2 1 K2 I KN I KN i KNR I KNR
I mile 1 ft/mil fps 1 ft Idesign' 320° Idesign! 320° ldesignl 320° ldesign' 320°
I I 1 1 1 1 I 1 1 1 1 I
Segment 1 I 1.501 51.60! 0.351 1 0.49 1 0.99 1 0.78 136.40 1 32.651 0.00 1 0.00 10.00 1 0.00
Reach 1 I 1 1 1 1 I I
I l I I I I I 1 1 1 1 !
Segment 1 I 2.801 12.801 0.311 1 1.26 1 0.52 10.42 18.00 1 7.171 0.00 1 0.00 1 0.00 1 0.00
Reach 2 I 1 1 i i I I
1 Flow 1 CBOD ! NBOD 1 D.O. 1
1 cfs 1 mg/1 1 mg/1 1 mg/1 1
Segment 1 Reach 1
Waste 1 1.158 1138.000 1 0.000 1 5.000
Headwaters! 0.150 1 2.000 1 0.000 1 7.440
Tributary 1 0.000 1 0.000 i 0.000 1 0.000
* Runoff 1 0.100 1 2.000 1 0.000 1 7.440
Segment 1 Reach 2
Waste 1 0.000 1 0.000 1 0.000 1 0.000
Tributary I 5.630 1 2.000 I 0„000 I 7.440
* Runoff 1 0.340 1 2.000 1 0.000 1 7.440
* Runoff flow is in cfsa/mile

. .
} `g~ ^ | Reach # | Geg Mi } D.O. | CBOD | NBOD | Flow }
^ 1 1 0.00 5"28 122.40 0.00 1.81
1 1 0.10 5.16 119.42 0.00 1.32
1 1 0.20 5.18 116.52 0.00 1.38
1 1 0.30 5.15 113.70 0.00 1.34
1 1 0.40 5.20 110.95 0.00 1.35
1 1 0.50 5.25 108.27 0.00 1.86
1 1 0.60 5"82 105.67 0.00 1.87
1 1 0.70 5.38 103.18 0.00 1.88
1 1 0.80 5.45 100.66 0.00 1.89
1 1 0.90 5.52 98.25 0.00 1.40
1 1 1.00 5.58 95.91 0.00 1.41
1 1 1.10 5.65 93.68 0.00 1"42
1 1 1.20 5.71 91.41 0.00 1.48
1 1 1.30 5.77 89.24 A.00 1.44
1 1 1.40 5.83 87.18 0.00 1.45
1 1 1.50 5.88 85.07 0.00 1.46
1 2 1.50 7.12 19.09 0.00 7.09
1 2 1.70 7.10 18.54 0.00 7.16
1 2 1.90 7.09 18.01 0.00 7.22
1 2 2"10 7.10 17.50 0.00 7.29
1 2 2.30 7.11 17.00 0.00 7.86
1 2 2.50 7.13 16.52 0.00 7"43
1 2 2.70 7.15 16.06 0.00 7.50
1 2 2.90 7.17 15.61 0.00 7.56
1 2 3.10 7.20 15.17 0.00 7.63
1 2 8.80 7.22 14.75 0.00 7.70
1 2 3.50 7.25 14.34 0.00 7.77
1 2 3.70 7.27 13.94 0.00 7.84
1 2 3.90 7.80 13.56 0.A0 7.90
1 2 4.10 7.32 13.19 0.00 7.97
| Seg # } Reach # | Geg Mi } D.O. i CBOD } NBOD | Flow |

,
.�
/
Discharger
Receiving Stream
WINTER
PRE-GOC
--- - MODEL RESULTS ----------
: PILOT MOUNTAIN WWTP SOC
x HEATHERLY CREEK
The End D.O. is 9.65 mg/l.
The End CBOD is 11.29 mg/l.
The End NBOD is 0.00 mg/l.
WLA WLA WLA
DO Min CBOD NBOD DO Waste Flow
(mg/l) Milepoint Reach # (mg/l) (mg/l) (mg/l) (mgd)
Segment 1 6.16 0.00 1
Reach 1 165 0.00 5.00 0.65700
Reach 2 0 0.00 0.00 0"00000

*** MODEL SUMMARY DATA ***
Discharger : PILOT MOUNTAIN WWTP SOC 2ubbasin a 030703
Receiving Stream a HEATHERLY CREEK Stream Class: C
Summer 7010 A 0.15 Winter 7010 a 0.38
Design Temperature: 14.
ILENGTH1 SLOPE! VELOCITY 1 DEPTHI Kl I KI 1 K2 1 K2 1 KN I KN I KNR 1 KNR
1 mile I ft/mi1 fps ! ft !design! aHPO° Idesign! a20° !design! i20° !design! 820°
I I I 1 1 1 I I 1 1 1 1
Segment 1 1 1.501 51.601 0.420 10.50 1 0.65 10.85 134.26 139.041 0.00 1 0.00 1 0.00 1 0.00
Reach i 1 1 1 1 1 1 1 1 1 1 1 1
1 ! 1 1 1 1 I 1 1 1 1 1
Segment 1 I 2.801 12.801 0.467 1 1.35 1 0.34 1 0.44 1 6.82 1 7.771 0.00 1 0.00 1 0.00 1 0.00
Reach 2 1 1 1 ! 1 1 I 1 I ! 1 1
I Flow 1 CLOD 1 NBOD 1 D.O. I
I cfs? 1 mg/1 1 mg/1 1 mg/1 I
Segment 1 Reach 1
Waste I 1.018 ! 165.000 1 0.000 1 5.000
Headwaters ! 0.380 1 2.000 1 0„000 1 9.280
Tributary I 0.000 1 0.000 1 0.000 1 0.000
* Runoff I 0.240 1 2 .000 j 0.000 1 9.280
Segment 1 Reach 2
Waste I 0.000 1 0.000 I 0.000 I 0.000
Tributary 1 10.130 I 2.000 I 0.000 ! 9.28ti
* Runoff 1 0.620 1 2.000 I 0.000 I 9.280
* Runoff flow is in cfs/mile

1 8eg # I Reach # I Beg Mi I D.O. I CE{OD 1 NBOD 1 Flow I
1 1 0.00 6.16 120.70 0.00 1.40
1 1 0.10 6.95 117.59 0.00 1..42
1 1 0.20 20 7.43 114.59 0.00 1.45
1 1 0.30 7.7...E 111.69 0.00 1.47
1 1 0.40 7.96 108.90 0,00 1.49
1 1 0.50 8.10 106.20 0.00 1.. 52
1 :1. 0.60 8.21 103.60 0.00 1.54
1 1. 0.70 8.29 101.08 0.00 1.57.
1 1 0.80 8.35 98.65 0.00 1 .59
i 1 0.90 8.41 96.31 0.00 1.61
1 1 1.00 8.46 94.03 0.00 1.64
1 1 1.10 8.51 91.84 0.00 1.66
1 1 1.20 8.55 89.71 0.00 1 .69
1 1 1.30 8.60 87.65 0.00 1.71
1 1 1.40 8.64 85.65 0.00 1.73
1 1 1.50 8.67 83.72 0.00 1.76
1 2 1.50 9.19 14.09 0.00 11.89
1 2 1.70 9.26 13.84 0.00 12.01
1 2 1.90 9.32 13.60 0.00 12.14
1 2 2.10 9.38 13.36 0.00 12.26
1 2 2.30 9.42 13.13 0.00 12.38
1 2 2.50 9.46 12.91 0.00 12.51
1 2 2.70 9.50 12.69 c:. c_ic_i 12.63
1 2 2.90 9.53 12.48 0.00 12.76
1 2 3.10 9.55 12.27 0.00 12.88
1 2 3.30 9 . 8 1. 2.06 0.00 13.00
1 2 3.50 9.60 11.86 0.00 13.13
1 2 3.70 9.62 11.67 0.00 13.25
1 2 3.90 9.64 11.48 0.00 13.38
1 2 4.10 9.65 11.29 0.00 13.50
I Seg # I Reach # 1 Beg Mi I D.O. 1 CBOD I NBOD 1 Flow I

.
/
,
^
,
MODEL RESULTS
Discharger : PILOT MOUNTAIN WWTP SOC
Receiving Stream x HEATHERLY CREEK
The End D.O. is 9.60 mg/l.
The End CBOD is 12.48 mg/l.
The End NBOD is 0.00 mg/l.
WINTER
POST SOC
WLA WLA WLA
DO Min CBOD NBOD DO Waste Flow
(mg/l) Milepoint Reach # (mg/l) (mg/l) (mg/l) (mgd)
Segment 1 6.06 0.00 1
Reach 1 165 0.00 5.00 0.74700
Reach 2 0 0.00 0.00 0.00000

*** MODEL_ SUMMARY DATA ***
Discharger n PILOT MOUNTAIN WWTP S(JC
Receiving Stream 4 HEATHERL_Y CREEK
Summer 7010 n 0.1'
Design Temperature: 14.
Subb ;es; i n n c�030703
Stream Class: C
Winter 7010 0.38
ILENBTHI SLOPEI VELOCITY 1 DEPTH! K1 I K1 I K2 I K2 I KN I KN 1 KNR 1 KNR
mile 1 ft/aril fps 1 ft Idesigni a20° !design! 820° ldesignl 320° Idesigni 820*
I 1 1 1 1 I I I 1 1 I 1
Segment 1 1 1.501 51.601 0.420 10.50 10.65 10.85 134.26 1 39.041 0.00 1 0.00 1 0.00 1 0.00
Reach 1 1 1 I 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 I 1 1 1 1 1
Segment 1 I 2.801 12.801 0.467 1 1.35 1 0.34 1 0.44 1 6.82 1 7.771 0.00 1 0.00 1 0.00 1 0.00
Reach 2 1 I 1 i 1 1 1 1 1 1 1 1
I Flow 1 CI3OD 1 1 1E{OD I D.O. I
1 cfs 1 mg/1 I mg/1 I mg/1 1
Segment 1 Reich 1
Waste I 1.158 i 165.000 i 0.000 0i } I 5.000
Headwaters! 0.380 1 2.c:00 i 0„000 I 9.280
Tributary I 0.000 l00 1 0.000 1 0.000 I 0.000
* Runoff I 0.240 1 2.000 i 0.000 I 9.280
Segment 1 Reach 2
Waste I 0„000 I 0,0c:0 i 0v000 I 0„000
Tributary i 10.130 I 2.00x I 0.000 I 9.280
* Runoff I 0.620 I 2.000 I 0.000 I 9.280
* Runoff flow is in cfs/mile

�
^,
`
�
.
,
| Seg # | Reach # ! Seg Mi | D.O. | CBOD | NBOD ! Flow |
1 1 0.00 6.06 124.72 0.00 1.54
1 1 0.10 6.85 121.68 0.00 1.56
1 1 0.20 7.34 118.75 0.00 1.59
1 1 0.30 7.66 115.91 0.00 1.61
1 1 0.40 7.87 113.17 0.00 1.63
1 1 0.50 8.02 110.51 0.00 1.66
1 1 0.60 8.12 107.94 0.00 1.68
1 1 0.70 8.20 105.45 0.00 1.71
1 1 0.80 8.27 103.04 0.00 1.73
1 1 0.90 8.38 100.70 0.00 1.75
1 1 1.00 8.38 98.44 O.00 1.78
1 1 1.10 8.43 96.24 0.00 1.80
1 1 1.20 8.47 94.11 0.00 1.83
1 1 1.30 8.51 92.04 0.00 1.85
1 1 1.40 8.55 90.04 0.00 1.87
1 1 1.50 8.59 88.09 0.00 1.90
1 2 1.50 9.17 15.58 0.00 12.08
1 2 1.70 9.23 15.31 0.00 12.15
1 2 1.90 9.29 15.04 0.00 12.28
1 2 2.10 9"34 14.78 0.00 12.40
1 2 2.80 9.38 14.58 0.00 12.52
1 2 2.50 9.41 14.28 0.00 12.65
12 2.70 9.45 14.04 0.00 12.77
1 2 2.90 9.47 13.80 0.00 12.90
1 2 3.10 9.50 13.57 0.00 13.02
1 2 3.30 9.52 13"34 0.00 13.14
1 2 3.50 9"54 13.12 0.00 13.27
1 2 3.70 9.56 12.90 0.00 18.39
1 2 8.90 9.58 12.69 0.00 18"52
1 2 4.10 9.60 12.48 0.00 13.64
| Seg # | Reach # | Seg Mi | D.O. | CBOD | NBOD i Flow |