Aquifer – An underground source of water made up of porous rock, like sand, shell or limestone.

Available Water – The difference between soil moisture content at field capacity and the point at which plants wilt due to lack of moisture little water remains available to the plant.

Biological Control – The use of living organisms to reduce populations of other living organisms-namely pests.

Environmental Impact Quotient (EIQ) – A method for quantifying the effect of pesticides on the environment, people, water and wildlife.

Eutrophication – The enrichment of bodies of fresh water by inorganic plant nutrients (e.g. nitrate, phosphate). It may occur naturally but can also be the result of human activity (cultural eutrophication from fertilizer runoff and sewage discharge) and is particularly evident in slow-moving rivers, shallow lakes, and impoundments.

Evaporation – The process by which water changes from a liquid into a gas.

Evapotranspiration – The sum of evaporation and plant transpiration from the Earth’s land surface to atmosphere.

Flow – The movement of water from one place to another.

Groundwater Recharge – The hydrologic process by which water enters into groundwater.

Hypoxia – Very low levels of dissolved oxygen in the water column

Infiltration – The process by which water is absorbed into the ground.

Leaching – The downward movement of a chemical or nutrient (e.g. pesticide or nitrogen from fertilizer) through the soil and potentially into groundwater.

Nonpoint Source – Nonpoint source pollution is caused by water moving over and through the ground picking up and carrying away natural and human-made pollutants and finally depositing them into lakes, rivers, wetlands, coastal waters and ground waters.

Nutrients – Elements as nitrogen and phosphorus compounds necessary for plant growth and survival. Elevated levels can cause unwanted growth of algae, and can result in the lowering of the amount of oxygen in the water when the algae die and decay.

Runoff – the movement of water across the turf and soil surface, typically following a storm event or heavy irrigation.

Sedimentation – The deposition of loose particles of sand, clay, silt, and other substances that settle at the bottom of a body of water. Sediment can come from the erosion of soil or from the decomposition of plants and animals.

Pesticide Drift – The U.S. Environmental Protection Agency defines spray or dust draft as “the physical movement of pesticide droplets or particles through the air at the time of pesticide application or soon thereafter from the target site to any non- or off-target site”.

(i>Pesticide Resistance – The decreased susceptibility of a pest population to a pesticide that was previously effective at controlling the pest.

Pesticide Volatilization – the chemical process whereby pesticide surface residues change from a solid or liquid to a gas or vapor after application. Once airborne, volatile pesticides may drift off site. Pesticide volatility varies, and not all pesticides volatilize

Point Source – A point source is a source of pollution from originating from a single identifiable source. However, this does not legally include agricultural storm water discharges and return flows from irrigated agriculture, including turf.

Stormwater – Water that originates in some form of precipitation as either rainfall or snowmelt.

Transpiration – Loss of water through the leaves of plants.

Watershed – An area of land that drains into a body of water (e.g. river, lake, reservoir, etc.) and  includes the network of rivers, streams and lakes that convey the water, as well as the land surfaces from which water runs off.

Water Table – Marks the very top of the ground water layer, and is the border between the unsaturated and saturated zone.