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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 �-+ 2 00 —1 Cl O O O O W O b i i tA O � � _� o 0�1 to O O O O ft o x z z o a ° o r �! p d PD y o rr p o 0 :. b m p OQ d o C] rA 2. C a, 80 tA C .r o ..yy V e y r p " eD o o o o o o o E o E' o eo " o " o " 0 " 0 " O O n y O () O C) y O Q O n O eo m a a a n �� n11 CD Q IZCi a a m a a a a a �i a O w g eo y rA 0 W N cn C A y N 1