Giardia lamblia-microorganism found in rivers and lakes; may cause diarrhea if ingested; removed by disinfection at water treatment plant.
Gray water-wastewater from household tubs, showers, sinks and washing machines, but not from kitchen sinks and dishwashers can be reused.
Ground Water
Ground water-water stored in natural reservoirs below the earth's surface (aquifer); water that can be pumped to the surface and used for drinking, irrigation and other uses. (See Ground water icon and diagram.)
Hardness-a measure of the natural concentration of alkaline salts in water, usually calcium and magnesium. Leaves a “film” on shower doors, scale on cooking pots; more soap is needed for a lather or detergent for washing clothes.
Headwater-the source of a stream or river.
Humidity-the amount of moisture in the air as measured by a percentage.
Hydroelectric power-using water to generate electricity; turbine generators driven by falling water.
Hydrogen-colorless, highly flammable element, exists as a gas; most abundant element in the universe. First on Periodic Table of Elements.
Water Cycle
Hydrologic cycle-transfer of water vapor from the Earth's surface by evapotranspiration into the atmosphere, back from the atmosphere by precipitation to the Earth, and then through runoff into streams, rivers, lakes, and ultimately into the oceans. (Cycle starts again. . . . ) Also water cycle.
Impermeable-rock, sediment or soil incapable of transmitting fluids under pressure. A clay layer is generally impermeable to water.
Infiltration-flow of water from the land surface into the subsurface.
Injection well-a well constructed for injecting treated wastewater directly into the ground for storage to increase ground water supplies. (artificial recharge.)
Inorganic compounds-mineral-based compounds such as metals or nitrates. Naturally occurring in waters, but can also be introduced as pollutants through human activities.
Intake-opening through which a fluid is admitted into a container or conduit.
Irrigation-controlled application of water for agricultural use.
