Wadi -steep-sided valley or ravine in desert and semi-arid areas. Usually only contain streams during flash-floods associated with heavy storm events.

Walker cell -a convectional cell in the tropical South Pacific which generally moves air in an east-west direction and is associated with el Ni?o..

Warm front -the front edge of a body of warm air where it meets and rises above a body of colder air.

Waste -the unwanted by-products of human activity. Create issues for disposal as much waste presents health dangers to people and other organisms, as well as problems of using up space.

Water balance -in any natural system, inputs of water must equal outputs plus or minus changes in storage since water cannot be created or destroyed.

Water cycle -see hydrological cycle.

Waterfall - a sudden vertical or near vertical fall of water where a river course is interrupted by a drop away in the land over which it is flowing.

Waterlogged -see saturated.

Water management -the attempt to provide the right quality of water for a variety of uses in the places where it is required. The most pressing is the need to provide fresh water as supplies are limited and not necessarily in sufficient quantities for growing centres of population.

Watershed - the line where drainage basins meet and which determines to which basin precipitation will go.

Water stress – the disparity between demand and supply of water in any particular area.

Water table -the upper boundary of the saturated portion of a soil or rock.

Wave -a movement of energy. In the oceans, waves are created by the frictional drag of wind on the surface of the water, or by undersea disturbances. At sea, they have little effect, but closer to coasts they develop into a horizontal movement of water which impact on the form of the coastline.

Wave-cut notch -the undercut portion of a cliff where the base has been eroded by wave action.

Wave-cut platform -at a coast, where wave action erodes into a cliff, causing it to collapse and retreat, a rock platform is left behind between the low and high water marks.

Wave-pounding -the breakdown of rock through the sheer impact force of waves. Large storm waves can exert forces of up to 30 tonnes per m².

Weather - the day-to-day state of the atmosphere.

Weathering -breakdown of rock in situ by physical and chemical processes due to the presence of water, plants and animals. Rates vary according to additional controls of temperature, rock type and time. (see physical weathering and chemical weathering).

Weber, Alfred -developed a model to explain the location of industry according to identification of the least-cost location. Full explanation:

http://teacherweb.ftl.pinecrest.edu/snyderd/APHG/Unit%207/weber.htm

Well -a hole dug or drilled into the ground to allow access to groundwater.

Wetland - an area of land that is permanently saturated up to or very near to the surface.

Wetted perimeter -that portion of a river? bed and sides which is in contact with the water.

White goods -domestic appliances.

Wholesale - the buying of goods in bulk from manufacturers or suppliers, either to be sold on in bulk or to reduce unit costs for retail.

Wilderness -areas of land that have never experienced any meaningful human activity.

Wilting point -the point at which water losses due to transpiration are greater than gains through the roots. Photosynthesis will begin to slow.

Wind -the horizontal movement of air created by differing pressures of adjacent air masses. Air moves from high to low pressure areas.                                                                                                          

Wind deposition -the return of wind-borne particles to the surface.

Wind erosion -the removal of particles from the surface by wind, and the degrading processes caused when these particles are thrown against rock.

Wind power -the generation of electricity by turbines which are turned by wind.

Wind transport -smaller rock particles may be carried by the wind, moved by saltation, or rolled along the surface.

Windward - the side of an island or ship against which the wind is blowing.

World Bank - http://www.worldbank.org/

World Health Organisation (WHO) -an office of the UN which overseas international efforts to improve general health conditions and to address international threats such as pandemics. http://www.who.int/en/

World Trade Organisation (WTO) - http://www.wto.org/