Related by context. Frequent words. (Click for all words.) 77 lakes rivers 66 rivers 65 waterways 61 lakes 58 freshwater 56 freshwater lakes 55 estuaries 52 inland waterways 52 underground aquifers 51 polluted 51 oceans 51 watersheds 51 watercourses 51 creeks 50 groundwater 49 ponds 49 tributaries 49 aquifers 49 aquatic ecosystems 49 estuary 49 unpolluted 48 pollutants 48 water 48 untreated sewage 48 inland lakes 48 river basin 47 toxic pollutants 47 canals 47 shorelines 47 streams 47 riverbeds 47 inland waterway 47 polluted runoff 46 Polluted 46 river 46 river basins 46 coastal waters 46 estuarine 46 waterway 45 riverbanks 45 lagoons 44 aquatic organisms 44 lake 44 transboundary 44 effluents 44 watercourse 44 raw sewage 44 headwaters 44 irrigated agriculture 44 wetlands 44 trout streams 43 fecal bacteria 43 beaches 43 river valleys 43 habitats 43 stormwater drains 43 brackish 43 nutrient pollution 43 contaminants 43 pollution 43 reservoirs 43 Ganges 42 Pollutants 42 sewage 42 coastlines 42 waters 42 sediment 42 wildlife habitat 42 Clean Water Act 42 Athabasca River 42 harmful pollutants 42 brackish water 42 nitrates 42 inland waters 42 marshes 42 ecosystems 42 storm drains 42 silt 42 Groundwater 41 wildlife habitats 41 effluent 41 sewage overflows 41 navigable waters 41 suspended solids 41 saltwater 41 waterfronts 41 pollutant 41 creek 41 Zebra mussels 41 drains 41 aqueducts 41 swollen rivers 41 sedimentation 41 coastal ecosystems 41 fecal coliform bacteria 40 tributary 40 trans boundary 40 aquatic species 40 freshwater fish 40 aquifer 40 Watersheds