Related by context. Frequent words. (Click for all words.) 79 basin 65 reservoirs 64 Basins 62 river basins 57 river basin 57 watersheds 54 Basin 54 aquifers 54 rivers 54 lakes 53 drainages 53 reservoir 53 geological formations 53 drainage basin 52 River basin 51 sediments 51 ponds 51 sediment 51 wells 51 groundwater 51 undrilled 51 tributaries 50 subsurface 49 hydrological 49 freshwater 49 dams 49 impoundments 49 aquifer 48 shales 48 coal seams 48 River Basin 48 catchments 48 headwaters 48 Reservoirs 47 groundwater recharge 47 water 47 hydrologic 47 soils 47 lagoons 47 geologically 47 underground aquifers 47 hydrocarbon 47 coalbed methane 47 sandstones 46 drainage 46 waterways 46 arid regions 46 gas hydrates 46 gas condensate 46 gravels 46 sedimentation 46 freshwater lakes 46 watercourse 46 shale deposits 46 wetlands 46 wetland 45 onshore 45 underground aquifer 45 Arkoma Basin 45 Aquifer 45 estuaries 45 hydrocarbons 45 shale 45 tributary 45 condensate 45 irrigated agriculture 45 hydrocarbon reserves 44 drainage ditches 44 crustal 44 creeks 44 watercourses 44 geologic 44 salt caverns 44 silt 44 sandy soils 44 storage tanks 44 landforms 44 oilfields 44 wells drilled 44 lodes 44 sewer mains 43 deltas 43 peat bogs 43 catchment 43 river valleys 43 deepwater 43 dewatering 43 groundwater pumping 43 geological 43 stratigraphic 43 shale gas 43 estuary 43 Sediment 43 horizontal wells 43 tailings 43 weirs 43 Ogallala Aquifer 43 wellbore 43 rock formations 43 meltwater 43 hydrology