Erosion is defined as the wearing away and transport of the soil by running water, glaciers, wind or waves. Sedimentation is the process of settling and depositing by gravity of suspended matter in water.
Water transforms landscapes and moves large amounts of soil and fine-grained materials in the form of sediment. Sediment is:
1) eroded from the landscape,
2) transported by river systems and eventually
3) deposited in a riverbed, wetland, lake, reservoir or the ocean.
Water is used by industry in a myriad of ways: for cleaning, heating and cooling; for generating steam; for transporting dissolved substances or particulates; as a raw material; as a solvent; and as a constituent part of the product itself (e.g. in the beverage industry).
- The water withdrawals for industry is:
- World: 22% of total water use.
- High-income countries: 59% of total water use.
- Low-income countries: 8% of total water use.
Industries based on organic raw materials are the most significant contributors to the organic pollutant load with the food sector being the most important polluter. Read more
Water pollution has been defined as the presence in water of harmful and objectionable material – obtained from sewers, industrial wastes and rainwater run-off – in sufficient concentrations to make it unfit for use.
We have long used air, land and water resources as ‘sinks’ into which we dispose of the wastes we generate. These disposal practices leave most wastes inadequately treated, thereby causing pollution. This in turn affects precipitation, surface waters, and groundwater, as well as degrading ecosystems.
Pollution from agriculture, industry and domestic wastewater is making water resources, both surface water and groundwater, increasingly scarce and decreasingly poor in quality.
An estuary is a body of water partially surrounded by land, where fresh water from a river mixes with ocean water.
Estuary habitats include salt marshes, mangroves, seagrasses, coastal forests and beaches.
Estuaries may form under a number of circumstances: at drowned river mouths, within steep glacially eroded fjords, within barrier islands or a barrier spit parallel to the coast, or within coastal indentations formed by faulting or local subsidence.
Tides define estuaries. Estuaries are washed either daily or twice daily with seawater. At high tide the salinity of the estuary will rise as sea water (20-35 parts per thousand of salt dissolved in the water) enters the estuary mixing with freshwater (0-0.5 parts per thousand) coming downstream. Estuary salinity can thus vary from 0-35 parts per thousand depending on the tide and amount of freshwater input.
The state of human health is inextricably linked to a range of water-related conditions: safe drinking water, adequate sanitation, minimized burden of water-related disease and healthy freshwater ecosystems.
Globally, diarrhoeal diseases and malaria accounted for 1.8 and 1.3 million deaths respectively in the year 2002.
Substantial progress has been made in reducing deaths associated with diarrhoeal disease: 2.9 million people died of diarrhoea in 1990, compared to 1.8 million in 2002, a decline of 37%.
Diarrhoeal diseases remain the leading cause of death from water-related diseases in children, accounting for 21% of all deaths of children under 5 in developing countries.