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I I I ! I I I I I I lhese studies and evaluations will necessitate a clear understanding (f the site's geologic character and groundwater depths, flow direc- tions and flow velocities. The volume and timing of leachate genera- !ton, as well as changes in leachate composition over time will also leed to be estimated. Finally, potentially affected groundwater sets will be identified including private and public' wells. Changes (n groundwater surfaces and flows due to changes in nearby ground- :iater pumping will also be defined and evaluated for effects on )eachate movement. The applicant is currently gathering data for the existin~ landfill, :)imilar to that mentioned above. The recodifed MPCA permit for the ~xisttng operation requires that hydrogeologic investigations 'be sufficient to delineate the areal extent and magnitude of the facility's current and probable future impacts on ground- water, particularly west and southeast of the facility, individ- ual, private and public water supply wells; the Minnesota River; Grass Lake and any other surface waters receiving groundwater influenced by the facility, including Purgatory Creek.' iThe permit goes further and specifies the studies that are required !(see attachment). . iFor the MPCA to evaluate a permit application for the proposed expan- ision, the same information will be required on the incremental ,effects of the proposed project. Therefore, the applicant must pro- ivide the information specified in Amended Permit SW-14, Part III IA.l.b, III A.i.c~ I'I A2 and III A3 and all of their subsections and ~IV A3 for the £IS This information must be modified or amended to ! ishow the characteristics and the effects of the proposed expansion. IIf ~his information proves inadequate to ascertain the proposed ~facility's impact, additional work may be required. For instance, i additional soil borings or piezometers may be needed. i After all the required information is available, the £IS will sum- ,~marize the pollution potential, evaluate human health risks and ~discuss mitigation techniques. It will also discuss the potential i for the project to alter groundwater levels. The contamination of i wells by organics, presently a subject of investigation, will be described in the £IS. i Surface Water quality ~ Landfills can alter surface waters in several ways. First, leach9te i travelling in the groundwater may eventually be discharged into ! surface water bodies. In the case of Flying Cloud Landfill, it is i possible that any leachate might discharge to Grass Lake and the i Minnesota River. Other surface water bodies such as the marsh and I Purgatory Creek to the east of the site could be affected. I The EIS will investigate in more detail the potential for leachate i to affect surface water bodies. It will identify areas that are f likely to receive any migrating leachate-, estimate the magnitude of t any pollution from leachate, and evaluate the sensitivity of.the i potentially affected areas. Some of the information needed to make