Related by context. Frequent words. (Click for all words.) 75 river basins 68 rivers 67 basin 67 River basin 65 tributaries 63 watersheds 63 River Basin 62 tributary 59 hydrological 59 river 59 headwaters 59 estuary 58 reservoirs 58 dams 58 freshwater 57 basins 57 aquifer 56 groundwater 56 aquifers 55 lakes 55 riparian 55 catchments 55 watershed 55 dam 55 waterways 54 waterway 54 wetland 53 catchment 53 floodplain 53 reservoir 52 Watershed 52 creeks 52 wetlands 52 hydropower 51 lake 51 water 50 irrigators 50 Reclamation 50 estuaries 49 Water Resources 49 River Watershed 49 hydroelectric dams 49 hydrology 48 Groundwater 48 creek 48 canal 48 rivers lakes 48 hydroelectric 48 Basin 48 hydroelectric dam 47 canals 47 Murray Darling Basin 47 River 47 floodplains 47 Dams 47 hydroelectric plants 46 salinity 46 drainages 46 Murray Darling 46 spillway 46 sedimentation 46 lowlands 46 stormwater 45 irrigation 45 sediment 45 downstream 45 Wetland 45 uplands 44 upstream 44 habitat 44 ponds 44 Lake Okeechobee 44 Indus River 44 damming 44 storages 44 flood plain 44 riverbanks 44 riverbed 44 hydro electric 44 dike 44 marshlands 43 Reservoir 43 dammed 43 catchment areas 43 untreated sewage 43 flood plains 43 Catawba River 43 semi arid 43 marshland 43 marshes 43 delta 43 drought stricken 43 ecosystems 43 lagoons 43 Lake Lanier 42 Ganges 42 weir 42 rainfall 42 cfs 42 floodway 42 cropland