Related by context. Frequent words. (Click for all words.) 52 Ogallala Aquifer 51 groundwater 49 aquifer 49 underground aquifer 47 polluted groundwater 47 contaminate groundwater 46 evaporation ponds 46 Edwards Aquifer 45 groundwater contamination 45 wellfield 45 dredged material 45 dredge spoils 45 aquifers 44 IEPA 44 groundwater basin 44 perchlorate contamination 44 contaminated groundwater 44 coal slurry 44 soil borings 44 coal gasification plant 44 Tittabawassee River 43 wastewater 43 hazardous waste landfill 43 sewage lagoon 43 coal ash 43 Napa Pipe 43 wastewater treatment 43 contaminated soil 42 Superfund site 42 Aquifer 42 SunCoke 42 contaminated sediments 42 Illiana Expressway 42 perchlorate 42 Fibrowatt 42 septage 42 sewer hookups 42 groundwater recharge 42 vapor intrusion 42 Chemical Waste Management 42 sewer 42 groundwater pumping 42 flood plain 41 Superfund cleanup 41 sanitary sewer 41 Powder River Basin 41 ash ponds 41 retention basins 41 fracking 41 acre tract 41 hydrofracking 41 water 41 landfill 41 floodplain 41 Washington Suburban Sanitary 41 Mecca Farms 41 Groundwater 41 Environmental Protection Agency 41 gravel pit 41 Tallevast 41 sewer mains 40 septic systems 40 Marcellus Shale formation 40 unnamed tributary 40 Environmental Quality 40 additive MTBE 40 Great Lakes basin 40 fracking fluid 40 stormwater drainage 40 contamination 40 drainage basin 40 sanitary sewers 40 Bradwood 40 retention ponds 40 poultry manure 40 stormwater runoff 40 OEPA 40 Watershed Protection 40 Pebble Mine 40 pollute groundwater 40 valley fills 39 Flambeau River 39 sediment 39 DEQ 39 wastewater discharge 39 Radiation Control 39 Pinon Canyon 39 Bradwood Landing 39 leachate 39 gravel extraction 39 NAWS 39 reservoir 39 fly ash 39 wetlands mitigation 39 basin 39 coalbed methane 39 stormwater 39 injection wells 39 gravel pits 39 sediment runoff 39 SEQRA