Section NR 214.21 - Groundwater monitoring requirements(1) APPLICABILITY. The department may require the generator of a liquid waste, the owner or operator of a liquid waste land treatment system or an independent liquid waste-handling contractor, if applicable, to design and install a groundwater monitoring well system depending upon the type and strength of liquid waste, the volume of discharge, the type of land treatment system, the rate of discharge to the land treatment system and the site characteristics of the land treatment system. This section applies to discharges of liquid wastes and does not apply to sites used for spreading sludge or by-product solids; groundwater monitoring may be required around sludge or by-product solid spreading sites in special cases as specified in s. NR 214.05. (a) For land treatment systems which receive liquid wastes and have a flow to land treatment equal to or greater than 1.0 million gallons per day, the generator of the wastewater, the independent contractor who uses the system or the owner or operator of the system shall install a comprehensive multi-level groundwater monitoring system. The monitoring system shall contain one or more well nests to monitor groundwater elevation, flow and quality.(b) For absorption pond, ridge and furrow, spray irrigation and subsurface absorption systems which receive any type of liquid waste and have a flow to land treatment of 15,000 gallons per day or more, but less than 1.0 million gallons per day, the generator of the wastewater, the independent contractor who uses the system or the owner or operator of the system shall install a single level groundwater monitoring system.(c) The department may require the generator of the liquid waste, an independent contractor who uses the system or the owner or operator of a land treatment system which receives any flow of liquid wastes to install a single level or a multi-level groundwater monitoring well system. Factors to be considered for this determination include waste strength and characteristics, volume of waste, dosage schedule, geology of the area (depth to groundwater and bedrock), soil type, and the ratio of the groundwater flow velocity to the hydraulic application rate.(d) The department may waive the requirement to install a groundwater monitoring well system for a land treatment system. Factors to be considered for granting this waiver may include: whether the system is operated at nutrient and hydraulic application rates which do not exceed the agronomic needs of the cover crop, whether the geology, soils and proposed hydraulic loading rate indicate that groundwater contamination is unlikely, the ratio of the groundwater flow velocity to the hydraulic application rate and the density of the waste material.(2) DESIGN, CONSTRUCTION, INSTALLATION, TESTING, DOCUMENTATION AND ABANDONMENT OF MONITORING WELLS. (a) Groundwater monitoring systems shall be installed in accordance with approved plans and specifications. The department will accept plans and specifications prepared by and submitted under the signature of a qualified hydrogeologist, soil scientist, engineer or other qualified individual. Qualifications shall include a degree from an accredited institution of higher education and field experience on soil investigation, interpretation and classification of geologic or hydrogeologic information.(b) Minimum acceptable standards for the design, construction, installation, documentation, development and abandonment of groundwater monitoring wells shall be in accordance with ch. NR 141.(c) The groundwater monitoring well system shall consist of an adequate number of wells to define groundwater flow direction and to judge the groundwater impacts from land treatment on the site. A background monitoring well shall be located upgradient and far enough away from the land treatment system that no impact from the treatment system is measured. The other monitoring wells shall be located downgradient from the land treatment system in the possible directions of groundwater flow. In the event the groundwater flow direction is not known, the department may require the downgradient wells to be installed approximately equal distance from each other and around the perimeter of the system.(d) Downgradient groundwater monitoring wells shall be located at least 10 feet beyond the outer edge of the waste application area. The department may require monitoring wells to be placed within, at or beyond the land treatment system design management zone.(e) The groundwater monitoring wells shall be tested to provide information on the hydrogeology of the site. 1. The saturated hydraulic conductivity of the aquifer around at least 3 of the monitoring wells shall be estimated by performing in-field tests. All preparation work, analysis and information describing the use of the in-field test shall be submitted along with the results obtained. The test shall be of sufficient duration and include enough data to provide a representative estimate of the actual hydraulic conductivity.2. The horizontal and, if possible, the vertical hydraulic gradient shall be calculated using measured groundwater elevations from on-site wells.3. The aquifer thickness and type of bedrock shall be determined through use of reliable reference material or by actual measurement.(f) As-built plans shall be submitted to the department after the wells are installed. The plans shall contain the following information: 1. A map shall be drawn to a specific scale and indicate the location of the land treatment system, all well location and elevation requirements as specified in s. NR 141.065, and the direction of groundwater flow. Land surface contours of the land treatment system and the elevations of the groundwater shall be referenced to the U.S. geological survey or the U.S. national geodetic survey.2. Well and borehole construction documentation listed in s. NR 141.23.(3) PLAN MAP. An 81/2²² by 11²² plan map drawn to scale according to a horizontal grid system shall be submitted that indicates the location of the land treatment system, the adjacent property boundaries and the location of all wells, wetlands, streams and lakes with in 0.5 miles of the land treatment system.(4) GROUNDWATER SAMPLE COLLECTION, ANALYSIS AND MONITORING REQUIREMENTS. (a) All groundwater monitoring well samples shall be collected, preserved and analyzed in accordance with procedures specified by the department in the"groundwater sampling guidelines," dated February 1987, and in accordance with s. NR 140.16.(b) All groundwater samples, except those analyzed for volatile organic compounds, shall be filtered through a standard 0.45 micron filter prior to analysis. If the groundwater sample is to be analyzed for metals, filtering shall be performed in the field immediately following sample collection. For all other types of analysis, filtering shall be performed in the field immediately following sample collection, unless the sample is cooled to 4° C and filtering is performed at the laboratory within 24 hours of sample collection.(c) Sulfuric acid preservation of groundwater samples to be analyzed for the nitrogen series and nitric acid preservation of groundwater samples to be analyzed for metals shall be performed immediately after the sample is filtered.(d) Monitoring shall be in accordance with the requirements of the plan approval or WPDES permit. For seasonal operations, groundwater monitoring shall be performed at a minimum of once prior to the startup of the land treatment system and 2 times during or within 2 months after the time the wastewater treatment system is used. The department shall specify in the WPDES permit the month during which the groundwater monitoring is to be performed and may adjust the frequency of groundwater monitoring for any land treatment system on a case-by-case basis.(e) The department may require groundwater monitoring for any of the following parameters: elevation, depth to groundwater, organic nitrogen, ammonia nitrogen, nitrate and nitrite nitrogen, chlorides, sulfates, dissolved solids, alkalinity, hardness, field pH, field specific conductance, BOD5, COD, sodium, calcium, magnesium, iron and manganese. Those facilities which have shown little or no measurable impact on groundwater quality may receive reduced parameter sampling requirements.(f) Monitoring for any other pollutant parameters may be required on a case-by-case basis dependent on the waste characteristics of the wastewater applied to the land treatment system and the potential for groundwater contamination.Wis. Admin. Code Department of Natural Resources NR 214.21
Cr. Register, June, 1990, No. 414, eff. 7-1-90.