Section 43.20 - Groundwater Drinking Supplies and Resource Protection(1)Exclusion Criteria.(a)Existing Public Water Systems Pumping More Than 100,000 Gallons per Day. Exclude sites located within the Zone III of an existing public water supply with a maximum approved pump rate of 100,000 gallons per day (gpd) or more.(b)Existing Public Water Systems. Exclude sites located within the Zone II of an existing public water supply.(c)Potential Productive Aquifer. Exclude sites located over a potential productive aquifer (PPA) which has been determined by the Department to be qualified for development as a public drinking water system prior to the issuance of the draft candidate site identification report pursuant to M.G.L. c. 111H,§ 20(c). Notwithstanding this exclusion, a site may be located within a PPA qualified for development where the site is proposed to be located outside of the Zone II of any system and outside of the Zone III for systems pumping 100,000 gpd or more.(d)Existing Private Ground Water Source or Non Community Water System. Exclude sites located within the Zone of Contribution of an existing private groundwater source or non-community system unless the source/system is located on the parcel of land that is designated to be acquired pursuant to M.G.L. c. 111H,§ 23(g) and the source/systemis secured from any use other than uses related to the construction, operation or environmental monitoring of the facility.(e)Potential Private Groundwater Source or Non-Community Water System. Exclude sites located within the projected Zone of Contribution of a potential private groundwater source or non-community water system unless the source/system is located on the parcel of land to be acquired pursuant to M.G.L. c. 111H,§ 23(g) and is secured from any use other than uses related to the construction, operation or environmental monitoring of the facility.(f)Sole Source Aquifer. Exclude sites which are located over the areal extent of a sole source aquifer.(g)Minimum Depth to Water Table. Exclude sites where the minimum depth to the water table is insufficient to prevent the intrusion of groundwater, perennial or otherwise, into the waste.(h)Minimum Depth and Overburden to Bedrock Water Table. Exclude sites where the water table is below the bedrock surface and where between the bedrock and the bottom of the waste management unit there is less than a minimum total thickness of ten feet of (unsaturated) soil units (natural or placed) with a maximum saturated hydraulic conductivity of 1x10(-4) cm/sec.(i)Maximum Horizontal Gradient. Exclude sites where the average horizontal gradient in the uppermost aquifer underlying the site is more than 0.01.(2)Conditional Consideration Criteria. (a)Depth to Water Table. Consider sites where the minimum depth to the water table is ten feet or less from the ground surface or from the bottom of the waste management area, if the waste management area is below the ground surface, on compliance with 310 CMR 43.40(3).(b)Horizontal Gradient. Consider sites where the average horizontal gradient in the uppermost aquifer underlying the site is 0.01. to 0.005 on compliance with 310 CMR 43.40(3).(c)Below Bedrock Water Table. Consider sites where the water table extends below the bedrock surface on compliance with 310 CMR 43.40(3).(3)Preference Criteria.(a)Horizontal Gradient. Prefer sites with a lower average hydraulic gradient in the uppermost aquifer underlying the site, over sites with a higher average hydraulic gradient in the uppermost aquifer underlying the site .(b)Depth to Water Table. Prefer sites with greater minimum depths to the water table below the ground surface, over sites with lesser minimum depths to the water table below the ground surface.(c)Hydraulic Conductivity. Prefer sites with an average hydraulic conductivity in the saturated soil of 1x10-(4) cm/sec. or less, over sites with an average hydraulic conductivity in the saturated soil of greater than 1x10-(4) cm/sec.(d)Groundwater Travel Time. Prefer sites with a predicted longer average travel time of ground water beneath the waste management area, over sites with a shorter predicted average travel time of ground water beneath the waste management area.