NR 214.13(2)(m)(m) The ridges shall be seeded with perennial grasses which are suited to wet soil conditions. A nurse crop shall be used to seed new or modified systems. In addition, the grass cover shall be established to at least a 2-inch length before the system is used for wastewater treatment.

NR 214.13(2)(n)(n) Precautions shall be taken during construction to minimize compaction of absorption areas to prevent a reduction in soil infiltration rate. Project specifications shall detail the specific precautions which will be taken.

NR 214.13(2)(o)(o) Erosion control measures shall be taken during construction to prevent erosion of soil into a surface water.

NR 214.13(3)(a)(a) The discharge to a ridge and furrow system may not exceed the hydraulic, organic, nitrogen, chloride or other limitations specified in a WPDES permit or plans developed pursuant to a permit requirement. In determining discharge limitations, the department shall consider past operating performance, the ability of the soils to treat the pollutants in the discharge, hydrogeologic characteristics of the site such as permeability and infiltration rates, and other relevant information.

NR 214.13(3)(b)(b) The concentration of any wastewater parameter that may impact groundwater quality shall be limited at the point of discharge to a value that will minimize the concentration of the substance in the groundwater to the extent technically and economically feasible and will prevent exceedence of the preventive action limit (PAL) in the groundwater. This will be especially important for parameters, such as dissolved chloride, that do not receive significant treatment in the system.

NR 214.13(3)(c)(c) The total pounds of nitrogen applied per acre per year shall be limited to the annual nitrogen need of the cover crop plus demonstrable nitrogen losses, such as from denitrification or ammonia volatilization occurring in the treatment system. Determination of the annual pounds of nitrogen applied to the land treatment system shall include the nitrogen supplied by the wastewater, organic nitrogen becoming available to plants and any supplemental fertilizers used.

NR 214.13(3)(d)(d) The average hydraulic application rate may not exceed 10,000 gallons per acre per day for the system.

NR 214.13 NoteNote: Based upon the department’s experience, the recommended range for the average hydraulic application rate for ridge and furrow systems is 2,000 to 5,000 gallons per acre per day.

NR 214.13(3)(e)(e) Discharge to the system shall be limited so that the discharge volume combined with the precipitation from a 10-year frequency, 24-hour duration rainfall event does not overflow the boundary of the system.

NR 214.13(3)(f)(f) The volume of discharge shall be limited to prevent inundation of the ridges except for temporary conditions following precipitation events.

NR 214.13(4)(a)(a) The discharge to each cell of the ridge and furrow system shall be monitored for total daily flow.

NR 214.13(4)(b)(b) The department may require in a WPDES permit that the discharge be monitored for BOD5, total suspended solids, forms of nitrogen, chloride, metals or any other pollutant that may be present. The department shall select the pollutants to be monitored and the required frequency of monitoring on a case-by-case basis by considering the potential public health impacts, probable environmental impact, soil and geologic conditions, past operating performance, concentrations and characteristics of pollutants in the discharge and other relevant information.

NR 214.13(4)(c)(c) The department may require electronic or paper submittal of discharge monitoring reports and land application forms.

NR 214.13(5)(a)(a) Each spring, the ridge top grasses shall be either cut and removed, or the grasses shall be burned. In addition, the grasses shall be cut and if possible removed at least once later in the growing season.

NR 214.13(5)(b)(b) The discharge shall be alternately distributed to individual sections of the ridge and furrow system to allow sufficient resting periods to maintain the treatment capability of the soil.

NR 214.13(5)(c)(c) The system shall be operated so that individual ridge and furrow sections have sufficient resting to allow soil conditions to become unsaturated and aerobic prior to being loaded.

NR 214.13(5)(d)(d) The system may be used only when at least 5 feet of separation exists between the bottom of the furrows and the groundwater.

NR 214.13(5)(e)(e) Management plan. The department shall require each ridge and furrow system owner or operator to submit a management plan for optimizing treatment system performance and demonstrating compliance with the requirements of this chapter. Following approval by the department, the treatment system shall be operated in conformance with the management plan. If the facility wishes to operate differently than specified in the approved plan, a written request shall be submitted to the department for approval to amend the management plan. The plan shall specify information on pretreatment processes, load and rest schedules, scheduled maintenance, vegetative cover control and removal, operational strategies for periods of adverse weather, monitoring procedures and any other pertinent information.

NR 214.13(6)(6) Soil investigation and groundwater monitoring requirements. The soil investigation and groundwater monitoring requirements for ridge and furrow systems are specified in ss. NR 214.20 and 214.21.

NR 214.14(1)(a)(a) A spray irrigation system shall be located at least 1,000 feet from a well serving a community public water supply system and at least 250 feet from other potable water supply wells.

NR 214.14(1)(b)(b) The nearest edge of wastewater spray shall be separated by at least 500 feet from the nearest inhabited dwelling, except that this distance may be reduced with the written consent of any affected owners and occupants. The department may require a greater distance depending on the type of distribution system and potential for aesthetic and public health impacts.

NR 214.14(1)(c)(c) The ground surface of the system shall have a minimum separation distance to bedrock and groundwater of at least 5 feet.

NR 214.14(1)(d)(d) A spray irrigation system may not be located in the floodway as specified in ch. NR 116. Any system located in the floodplain shall conform to ch. NR 116 and may not be operated when the floodplain is flooded.