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GLOSSARY |
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CONTENTS PAGE | RESOURCE MATERIAL | WATER RESOURCES HOME
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GLOSSARY |
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Abdomen - the last of the three body segments of an insect. The tail is part of the abdomen.Acid (Acidic) - anything with a pH of less than 7. Lemon juice, vinegar, and soda are acids.
Aeration tank - the first stage of secondary treatment of wastewater. Here, sewage is mixed with air and bacteria so that any organic material is broken down.
Aquifer - a large underground water source that can readily transmit its water. The upper surface of the aquifer marks the water table.
Base (Basic or Alkaline) - anything with a pH of greater than 7. Bleach, baking soda, and ammonia are bases.
Best Management Practices (BMP's) - a set of field activities that provide the most effective means for reducing pollution from a non-point source.
Catskill System - part of the NYC water supply system, it consists of the Ashokan and Schoharie Reservoirs, the Catskill Aqueduct, and the Shandaken Tunnel.
Chlorination - the final step before the discharge of treated wastewater, where chlorine is added. Chlorine is also used to kill bacteria in drinking water supplies.
Clarifier - the final place where solids settle out of the wastewater before discharge. Chlorine is usually the only thing added after this stage.
Comminutor - the initial step of the wastewater treatment process. Large objects are screened out before the next step, the grit chamber.
Condensation - a change in state where water vapor becomes a liquid.
Contour Lines - lines drawn on a map so that every point along that line is the same elevation above sea level.
Croton System - the oldest part of the NYC water supply system. Currently, it consists of 13 interconnected reservoirs, three controlled lakes, and the Croton Aqueduct.
Cryptosporidium - a disease that is transmitted through contact with animals (especially cattle and sheep), other humans, or contaminated water supplies. Diarrhea is the most common symptom.
Delaware System - part of the NYC water supply system, it consists of the Cannonsville, Neversink, Pepacton, and Rondout Reservoirs, the East and West Delaware Tunnels, the Neversink Tunnel, and the Delaware Aqueduct.
Dissolved Oxygen (DO) - the amount of oxygen that is present in water. Cold and flowing water usually contains more DO than warm, stagnant water. Measured in parts per million(ppm)or mg/l.
Drainage Divide - the raised land that separates two watersheds.
Drainage Pattern - the network of streams that drain a watershed(s). A "branched" pattern is the most common, and found throughout the Catskills.
Evaporation - a change in state where water as a liquid becomes a gas (vapor).
Evapotranspiration - collectively, the processes that return liquid water to the gaseous state. This includes evaporation and transpiration (evaporative water loss from plants).
Giardia - a waterborne disease resulting from the intake of the Giardia protozoan. Symptoms include abdominal cramps, intermittent dysentery, and weight loss.
Grit Chamber - the place where sand, small stones, and grit are settled out of the wastewater in a treatment plant.
Groundwater - water under the ground. It accounts for 20 % of the earth's freshwater, or ½ of 1% of all the water on Earth.
Head - the first of the three body segments of an insect. Eyes and antennae are part of the head.
Hydrologic Cycle - the continuous process by which water is recycled on Earth. Also called the "water cycle".
Impacted - the NYSDEC's term for a stream that does not meet all of its pollution screening criteria.
Infiltration - the sinking or soaking, of water from the atmosphere into the ground.
Leaching - the process by which impurities in groundwater are naturally filtered out by the soil over a period of time.
Macroinvertebrates - non-microscopic animals without backbones. Most are insects.
Memorandum of Agreement (MOA) - a contract signed in 1997 by the Coalition of Watershed Towns, New York City, the State of New York, The US EPA, and various non-profit environmental organizations. This agreement allows NYC to begin the process of meeting the EPA's drinking water standards without having to build a filtration plant.
Molecule - the result of atoms joining together, the smallest unit of an element or compound. The water molecule is composed of two hydrogen atoms and one oxygen atom.
New York City Watershed - a 1,900-square-mile (1,600 mi2 in the Catskills) area of land that collects and stores water for the City to use. It consists of the Catskill, Delaware, and Croton Systems.
Non-Impacted - the NYSDEC's term for a stream that meets all of its pollution screening criteria.
Non-point Source (NPS) - pollution resulting from more than one source, and usually over a very large area. Examples include: acid rain, runoff, and animal waste.
Parts per million (ppm) - a unit of measurement (for dissolved oxygen) equal to a mg/l.
Percent Oxygen Saturation - the amount of dissolved oxygen in water relative to how much it can store at a particular temperature.
Percolation - the process of water moving through pores (spaces between soil particles) in the soil. Water percolates faster where pore spaces are larger.
pH - a measurement of the number of hydrogen ions (H+) or hydroxide ions (OH-) in a solution. Acids produce hydrogen ions and bases produce hydroxide ions.
pH Scale - the range from 0 to 14 of pH units. Neutral solutions have a pH of 7, while acidic solutions approach 0, and basic ones approach 14.
Photosynthesis - the process by which plants make food using sunlight carbon dioxide and water.
Piezometer - a type of well that is used to find the depth of the water table by and measuring the level of the water in it.
Point Source - pollution that comes from a known source. An example is a discharge pipe.
Precipitation - rain, snow, sleet, or hail.
Sedimentation - the process by which larger, denser particles settle to the bottom and lighter particles stay suspended in water for a longer period of time.
Sedimentation tank - the stage of the wastewater treatment process where the solids settle to the bottom as pure sludge, and the remaining water is moved on to the aeration tank.
Solvent - a liquid with the ability to dissolve other substances. Water is the most common solvent, and often called the "universal solvent" because it dissolves many substances.
Sub-Watershed - a smaller watershed that is a piece of a much larger watershed. For example, the Esopus Creek watershed is a sub-watershed of the Hudson River watershed.
Surface Runoff - water flowing above ground that enters surface water bodies.
Thorax - the middle segment of an insect. Includes the legs and wings if present, and sometimes the gills.
Topography - the shape of the surface of the Earth.
Transpiration - the process of plants losing water through their leaves due to evaporation.
Turbidity - a measurement of how "cloudy" water is. Suspended soil particles in water will make it turbid.
Water Table - the top level of the underground aquifer. Which is also the top of the zone of saturation.
Water Vapor - water in the gaseous state in the Earth's atmosphere. Water vapor is invisible.
Watershed - the area of land that collects water and releases it to a common outlet. After collecting water, a watershed will temporarily store it, and subsequently release its water to a particular surface water body.
Zone of Saturation - the area below the Earth's surface where all pore spaces in soil are completely filled with groundwater.
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