This graphic illustrates the impact of human activity on groundwater. It shows that groundwater is obtained from periurban wellfields and urban wells, then used and disposed of as wastewater through pluvial drainage, piped sewage and on-site sanitation and industrial effluent disposal. It also shows that wastewater is treated and then reused for irrigation, with excess flows re-entering the aquifers.

The harvest of freshwater fish is likely to increase either through capture fisheries or aquaculture (otherwise known as 'fish farming'). This graphic shows inland capture fisheries trends at the national level for 1984 to 1997, and illustrates the ratio between the 1998 catch and the maximum recorded catch in various marine fishing zones around the world.

Straddling the borders of Nigeria, Chad, Niger and Cameroon in West Africa, Lake Chad has been a source of freshwater for irrigation projects in all these countries. This graphic traces the shrinkage of Lake Chad and changes in vegetation from 1963 to 2001. It includes maps of the lake from 1963, 1973, 1987, 1997 and 2001. Climatic changes and high demands for agricultural water are responsible for the lake's shrinkage.

Similar to corals, the region of greatest mangrove diversity is in Southeast Asia, particularly around the Indonesian Archipelago (Burke et al., 2001). There are three distinct areas of seagrass diversity in the Pacific region: the Indo-Pacific (areas around Indonesia, Malaysia, and Papua New Guinea), the seas around Japan, and southwest Australia (Spalding et al., 2002). This graphic illustrates the distribution and biodiversity (low, medium and...

There is growing evidence that many marine species are less widely distributed, and therefore more vulnerable to extinction, than previously thought. This graphic shows the diversity of marine mammals, sharks, molluscs, birds, and shrimps and lobsters in the world's marine areas. The data have been modified to show the species diversity of each region as a fraction of the most species-rich region.The maximum number of marine mammals species in a ...

Physical alteration and destruction of habitats are now considered one of the most important threats to coastal [and marine] areas. This graphic shows the extent to which twelve different human activities cause environmental degradation in estuaries, inter-tidal wetlands and the open ocean. The activities include the drainage of coastal ecosystems; the construction of dykes, dams and seawalls and the mining of wetlands.

This graphic shows the average calcium levels, in milligrams per litre, at major river mouths for the time periods 1976 to 1990 and 1991 to 2000. The graphic also shows the changes in average calcium levels between these two time periods.

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Major observed threats to the world's coral reefs include tourism, poison fishing, overexploitation, sedimentation, coral harvesting, dynamite fishing and pollution. This graphic explains which activities or conditions are affecting various coral reefs throughout the world. The graphic 'Major Threats to Reefs' shows the percentage of reefs that are threatened by overexploitation, coastal development, inland pollution and marine pollution, and the...

Throughout the 20th century, global water use has increased in the agricultural, domestic and industrial sectors. Evaporation from reservoirs has increased at a slower rate. Projections indicate that both global water use and evaporation will continue to increase. This graphic shows water consumption, withdrawal and waste, in cubic kilometres per year, for the agricultural, domestic and industrial sectors, and shows evaporation from reservoirs. T...

Over the past 30 years, the Aral Sea in the former Soviet Union has shrunk to less than half of its original size. This graphic shows the Aral Sea as it was in 1960 and as it appeared in 2001. It shows that a former fishing zone is now a dry zone affected by salination. Areas that were previously food crops (partly irrigated) are now cotton and rice crops, widely irrigated. Other changes include the replacement of fish exports with fish imports, ...

This graphic shows the changes in water supply and wastewater disposal that occur through four stages of growth of a settlement: early settlement; the town becomes a city; the city expands and the city expands further. The changes include increased groundwater pollution and changes in pluvial drainage, the water table and wellfields.

The DPSIR framework (Driving Forces-Pressures-State-Impacts-Responses) is used to assess and manage environmental problems. Driving forces are the socio-economic and socio-cultural forces driving human activities, which increase or mitigate pressures on the environment. Pressures are the stresses that human activities place on the environment. State, or state of the environment, is the condition of the environment. Impacts are the effects of envi...

This graphic makes it possible to compare water use by the agricultural, industrial and domestic sectors at the national level. The graphic indicates which sectors are the dominant and significant users of water in each country.

Rivers form a hydrological mosaic, with an estimated 263 international river basins covering 45.3% of the land surface area of the earth, excluding Antarctica. This graphic shows the locations of 26 of the world's major river basins. A basin is defined as the land area (watershed) where all surface water drains to a certain river.

Estimates of global water resources based on several different calculation methods have produced varied estimates. This graphic illustrates the proportions of saltwater and freshwater that make up the earth's water resources. It also shows what percentage of the world's freshwater is located in lakes and river storage; in groundwater, including soil moisture, swamp water and permafrost, and in glaciers and permanent snow cover.