Ключевые слова: canal, catchment, contaminate, contamination, culvert, danger, dirty, drain, drainage, drainpipe, ecology, environment, environmental, flood, floodwater, flow, flowing, fluid, garbage, industrial, industry, liquid, nature, old, pipe, pipeline, pipes, pollute, polluted, polluter, polluting, pollution, river, round, runoff, sewage, sewer, sewerage, sluice, stream, substance, toxic, treatment, tube, tunnel, unclean, waste, wastewater, water, waterway,