Section 206.10. Groundwater monitoring.

 

(1)   Design criteria. The design criteria and construction standards for a groundwater monitoring well shall conform to s. NR 110.25 (5) and ch. NR 141 .

(2)   Construction requirements.

(a) Approval of plans and specifications for groundwater monitoring wells installed after the treatment facility has been constructed is required for any well which is to be used as a permanent groundwater monitoring well.

(b) If wells were installed prior to treatment facility construction, department approval for use of these wells as permanent groundwater monitoring wells is required and is conditional, based on documentation that the wells were constructed in conformance with ch. NR 141 .

(3)   Monitoring requirements.

(a) For systems approved on or before December 1, 1990, monitoring requirements shall be based on average daily flow.

(b) For systems modified or approved after December 1, 1990, monitoring requirements shall be based on average daily flow.

(c) If the system has a design or average daily flow less than 0.015 MGD, the department may require groundwater monitoring if there is reason to believe contamination of groundwater is occurring.

(d) If the system has a design or average daily flow equal to or greater than 0.015 MGD, groundwater shall be monitored at a minimum of one level, at locations specified in the permit, and may include monitoring at more than one level. The department may waive this requirement on a case-by-case basis. Criteria which will be evaluated to waive this requirement include degree of treatment of the effluent, depth to groundwater and bedrock, nature of the bedrock, soil permeability, directions and rate of groundwater flow, vertical and horizontal flow gradients, existing groundwater quality, downgradient uses of the groundwater and compliance with ch. NR 140 standards.

(e) Groundwater elevation within the land disposal system shall be monitored through the use of a water table observation well for all land disposal systems that have a depth to groundwater from cell bottom of less than 5 feet.

(4)   Sampling frequency.

(a) For systems where background water quality has been established, the groundwater sampling frequency shall be quarterly.

(b) For systems where background water quality has not been established, the groundwater sampling frequency shall be every 6 to 7 weeks until 8 representative samples have been obtained, and shall be quarterly thereafter.

(c) The department may modify the sampling frequency on a case-by-case basis.

(5)   Parameter list.

(a) The department may require groundwater monitoring for any or all of the following parameters in filtered or unfiltered samples: elevation, BOD 5 , field specific conductance, COD, organic nitrogen, ammonia nitrogen, nitrate plus nitrite nitrogen, chlorides, sulfates, total dissolved solids, alkalinity, hardness, temperature and pH.

(b) Monitoring for other parameters may be required on a case-by-case basis if there is reason to believe contamination is occurring or if these contaminants are present in the wastewater, to determine compliance with the groundwater quality standards in ch. NR 140 .

(6)   Sampling procedures. Groundwater sampling procedures shall comply with the methods contained in s. NR 140.16 .

(7)   Analytical procedures.

(a) The methods of analysis for substances contained in groundwater samples shall be those in ch. NR 219 .

(b) Sample analysis used for permit reporting shall be performed by a laboratory certified or registered under ch. NR 149 .

History: Cr. Register, March, 1985, No. 351 , eff. 4-1-85; r. and recr. Register, November, 1990, No. 419 , eff. 12-1-90.