Section 444.7483 - Requirements concerning system for monitoring groundwater1. The owner or operator of a municipal solid waste landfill unit shall install a system for monitoring groundwater which consists of a sufficient number of wells, installed at appropriate locations and depths, to yield samples of groundwater from the uppermost aquifer which: (a) Represent the quality of background groundwater which has not been affected by leakage from the unit. A determination of background quality may include the sampling of wells that are not hydraulically upgradient of the waste management area if: (1) Hydrogeologic conditions do not allow the owner or operator to determine which wells are hydraulically upgradient; or(2) Sampling at other wells will provide an indication of the quality of the background groundwater which is as representative or more representative than that provided by the upgradient wells.(b) Represent the quality of groundwater at the boundary of the waste management unit. The monitoring system must be installed to ensure detection of contaminants in the groundwater in the uppermost aquifer. When physical obstacles preclude installation of wells to monitor groundwater at the boundary of the waste management unit, a downgradient monitoring system may be installed at the closest practicable distance hydraulically downgradient from the boundary which ensures detection of contamination of groundwater in the uppermost aquifer.
2. If a disposal site has more than one municipal solid waste management landfill unit, the solid waste management authority may approve a system for monitoring groundwater with multiple units instead of separate systems for each municipal solid waste landfill unit, if the system complies with the requirements of subsection 1 and is as protective of public health and safety and the environment as the separate systems. To approve a system with multiple units, the solid waste management authority shall consider the:(a) Number, spacing and orientation of the municipal solid waste landfill units;(b) Hydrogeologic setting;(c) History of the disposal site;(d) Engineering design of the municipal solid waste landfill units; and(e) Type of waste accepted at the municipal solid waste landfill units.3. Monitoring wells must be cased in a manner which maintains the integrity of the bore hole of the monitoring well. The casing must be screened or perforated and packed with gravel or sand, if necessary, to enable the collection of samples of groundwater. The annular space above the sampling depth must be sealed to prevent contamination of samples and the groundwater.4. The owner or operator shall notify the solid waste management authority that documentation concerning the design, installation, development and decommission of any monitoring wells, piezometers and other measurement, sampling and analytical devices has been placed in the records of the site. The monitoring wells, piezometers and other measurement, sampling and analytical devices must be operated and maintained so that they perform to design specifications throughout the life of the monitoring program.5. The number, spacing and depths of the monitoring systems must be:(a) Determined based upon technical information for each specific site, including a thorough characterization of the:(1) Thickness of the aquifer and the rate and direction of the flow of groundwater, including seasonal and temporal fluctuations; and(2) Saturated and unsaturated geologic units and fill materials overlying the uppermost aquifer, materials comprising the uppermost aquifer and materials comprising the confining unit defining the lower boundary of the uppermost aquifer, including, without limitation, the thicknesses, stratigraphy, lithology, hydraulic conductivities, porosities and effective porosities of these materials; and(b) Certified by a qualified groundwater scientist and approved by the solid waste management authority. Within 14 days after receiving certification and approval, the owner or operator shall place the certification in the records for the site.6. As used in this section: (a) "Annular space" means the space between the bore hole and well casing.(b) "Boundary of the waste management unit" means a vertical surface located at the hydraulically downgradient limit of the unit that extends down in the uppermost aquifer.Nev. Admin. Code § 444.7483
Added to NAC by Environmental Comm'n, eff. 11-8-93