GEF

149 Glossary NONPOINT SOURCE  A non-specific or dispersed source of water pollution, such as farm fields. NON-POTABLE  Water that is unsafe to drink. PEAK WATER  A concept that emphasizes that accessible, clean water is being used unsustainably and is becoming depleted and unavailable over much of the planet. PER CAPITA  A measure of average use per person. PERCOLATE  The movement of a liquid through a porous material. PERMAFROST  Permanently frozen soil that releases CO 2 and methane as it melts. PERMEABLE PAVEMENT  Pavement created from a range of sustainable materials and techniques that allow the movement of storm water through the surface. pH  A measure of the acidity or basicity of a liquid. PHOTOSYNTHESIS  The production of carbohy- drates from carbon dioxide and hydrogen in the chlorophyll-containing tissues of plants in the pres- ence of light. PHYTOPLANKTON  Tiny photosynthesizing organ- isms that inhabit the upper layers of the ocean where sunlight is able to penetrate. POINT SOURCE  A single or confined source of water pollution, such as a factory outflow pipe. POLARITY  A separation of electrical charges within a molecule. POTABLE  Water that is suitable for drinking. PRECIPITATION  Water falling from the atmosphere as rain, snow, or hail. PRIVATIZATION  The transfer of a business, industry, or service from public to private ownership and control. QANAT  A gently sloping underground channel or tunnel constructed to lead water from the interior of a hill to a village below. RAIN SENSOR  A switching device connected to an automatic irrigation system that causes the system to shut down in the event of rainfall. RAINWATER HARVESTING  Accumulating and storing rainwater for human use. RENEWABLE ENERGY  Energy produced from resources that can sustain themselves indefinitely, such as wind and solar power. RESERVOIR  A location that is part of the water cycle in which water is held, such as the oceans or groundwater. RESIDENCE TIME  The length of time that water spends in sections of the water cycle. RESPIRATION  The biological process by which cells use oxygen to break down sugar and produce energy. RIVER DELTA  A landform created by sediment deposited by a river flowing into an ocean, sea, desert, estuary, lake, or another river. RUNOFF  Water flowing from a land area, such as a farm field or urban area. SAFE DRINKING WATER ACT  The primary fed- eral law in the U.S. that regulates public drinking water quality. SALINIZATION  A buildup of minerals and salts in the soil that renders it sterile. SEDIMENTATION  An increase in suspended par- ticles in water bodies. SEMICONDUCTOR  A basic component of various kinds of electronic circuit elements, or the material used to make them.