HomeMy WebLinkAbout090017_Recommend End Grndwater Monitoring_20200114MEMORANDUM
To: Christine Lawson & Ramesh Ravella
Cc: Trent Allen, Mark Brantley and Steve Guyton
From: Kent White
Date: January 14, 2020
RE: Allen Brother's CAFO Permit Renewal, Permit No. 09-0017
Recommended Termination of Groundwater Monitoring
There are currently three monitoring wells associated with the Allo;Brother's CAFO permit that are being
sampled on a regular basis.
It is my understanding that:
• The residential well was sampled as part of a complaint regarding a swine operation,
• The monitoring wells were required by the state because nitrates were detected in a residential
supply well, located near the farm, above the 2L standards, and
• Construction of the supply well was not investigated, and
• According to BIMS, the monitoring wells have been monitored since 2004 (approximately 16
years).
We were contacted by Allen Brothers to determine whether the monitoring could be discontinued.
Therefore, Steve Guyton and I went to the site to investigate the situation. According to our limited
investigation:
• The residential supply well was not constructed to 2C standards as it was not grouted, and was
located approximately 20-feet from the residential septic tank (location of the tank was confirmed
when the Allen Brothers helped pull the residence's International "Farm -All" tractor out of it),
• The tract of land the monitoring wells were installed on has been in continuous cultivation for
decades utilizing conventional fertilizers, and is exempt from complying with 2L ground water
standards (15A NCAC 02L .0106 (c)) since it is an agricultural operation,
• The residence and church is no longer using supply wells and are on county water, and
• The nutrient signature of the groundwater does not match that associated with swine waste.
Based on these conditions, I am recommending we discontinue the monitoring program. I have provided
the following discussion to support my recommendation.
representative of the nutrients associated with a swine operation. Placement of the existing monitoring
wells produce data associated with nutrient loading from row crop farming, which is exempt from 2L.
Based on the following, I recommend terminating the ground water monitoring:
• Receptors were not observed (the residence and the church are both on county water),
• The monitoring wells are located such they are monitoring the nutrients from the a row crop
operation, not the permitted swine operation,
• The nutrient signature is typical of row crop operations, not swine operations, and
• The tract of land being monitored is exempt from 2L compliance.
Swine Waste Comparison for Nitrogen Signature Evaluation
Shaw Enforcement - Example of the Nutrient Profile
of Swine waste
Sample ID
TKN
NH3
NO2 & NO3
NH31NO2NO3
Ratio
phosphorous
Tile Down Str.
14
6.9
0.51
13.5 to 1
1.8
Dam @ L-3
14
8.7
0.3
29 to 1
0.95
Down Str.
3.1
1.4
0.24
5.8 to 1
0.24
Storm Enforcement - Example of the Nutrient Profile
of Swine Waste
Sample ID
TKN
NH3
NO2 & NO3
NH31NO2NO3
Ratio
phosphorous
Source
480
440
1.2
366.7 to 1
43
Lagoon No. 3
1 590
1 510
1 0.8
637 to 1
21
Melvin Enforcement - Example of the Nutrient Profile
of Swine Waste
Sample ID
TKN
NH3
NO2.NH
& NO3
3 /NO NO 3
Ratio
Phosphorous
Source
134
112
1.06
105.7 to 1
11
Ditch
33.3
27.9
1.64
20.3 to 1
2.0
Allen Brothers - Ground Water
Monitoring Event (2/28/2019)
Sample ID
TKN
NH3
NO2 & NO3
NH31NO2NO3
Ratio
phosphorous
MW-1
<0.20
<0.02
19
NA
<0.02
MW-2
0.52
<0.02
12
NA
<0.02
MW-3
0.39
<0.02
12
NA
<0.02
Tile Up Stream
1.6
0.27
<0.02
NA
0.09
Background
2.1
0.55
<0.02
NA
0.19
Background
<1.0
<0.05
1.4
NA
<0.05
Swine Waste Comparison for Nitrogen Signature Evaluation
Shaw Enforcement - Example of the Nutrient Profile
of Swine waste ,
Sample ID
TKN
NH3
NO2 & NO3
NH3/NO2NO3
Ratio
Phosphorous
Tile Up Stream
1.6
0.27
<0.02
NA
0.09
Tile Down Str.
14
6.9
0.51
13.5 to 1
1.8
Dam @ L-3
14
8.7
0.3
29 to 1
0.95
Down Str.
3.1
1.4
0.24
5.8 to 1
0.24
Storm Enforcement - Example of the Nutrient Profile
of Swine Waste
Sample ID
TKN
NH3
NO2 & NO3
NH31NO2NO3
Ratio
phosphorous
Background
2.1
0.55
<0.02
NA
0.19
Source
480
440
1.2
366.7 to 1
43
Lagoon No. 3
590
1 510
0.8
637 to 1
21
Melvin Enforcement - Example of the Nutrient Profile
of Swine Waste
Sample ID
TKN
NH3
NO2 & NO3
NH31NONO3
Ratio
phosphorous
Background
<1.0
<0.05
1.4
NA
<0.05
Ditch
33.3
27.9
1.64
20.3 to 1
2.0
Source
134
112
1.06
105.7 to 1
11
Allen Brothers - Ground Water
Monitoring Event (2/28/2019)
Sample ID
TKN
NH3
NO2 & NO3
NH31NO2NO3
Ratio
phosphorous
MW-1
<0.20
<0.02
19
NA
<0.02
M W-2
0.52
<0.02
12
NA
<0.02
M W-3
0.39
<0.02
12
NA
<0.02
Allen Brothers - Groundwater Flow Direction
3/2018
3/2019
3/2018
3/2019
Difference
Station
TOC1 Elev.
Z
Water Level
Z
Water Level
DTW
DTW
in Elevation
Elev.
Elev.
MW-1
102.25
13.8
88.45
8.74
93.51
5.06
MW-2
93.95
7.03
86.92
3.35
90.60
3.68
MW-3
95.77
8.84
86.93
5.15
90.62
3.69
1TOC = Top of Casing
2DTW = Depth to Water, 3/26/2019 Data
!- A W N �-+
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