We've compiled a glossary of terms and phrases related to the IWRM plan that are commonly used throughout this site. We hope you find it helpful. If you believe we've overlooked some, please let us know through our Contact Us Form.
Best Management Practices (BMPs) - The most effective and practical ways to control non-point sources of pollution from storm water/urban runoff.

Catch Basin - A below grade structure that has an open (grated) top cover to allow storm water to enter. Storm water is then sent downstream through storm drainage piping. Catch basins typically have a sump below the outlet pipe to collect and prevent sediment and debris from passing through the pipe and causing clogs. This sediment and debris needs to periodically be cleaned out.

Centralized Wastewater Treatment System - A wastewater treatment system for collection, treatment, and discharge to surface water or reuse of wastewater from a relatively large number of homes, businesses, and institutions. Centralized systems usually provide treatment of sewage in a treatment facility at the lowest elevation in the collection system prior to discharge to a river or lake. Centralized systems in Vermont are generally owned, operated, and managed by municipalities.

Decentralized Wastewater Treatment System - Wastewater treatment system for collection, treatment, and subsurface soil dispersal or reuse of wastewater from individual homes, clusters of homes, isolated communities, industries, or institutional facilities, at or near the point of waste generation. Decentralized wastewater systems may be either privately or municipally owned, operated, and managed.

Depth To Seasonality High Groundwater - The depth from the surface of the ground to the location of seasonally high groundwater, usually identified as mottling (color change) in a test pit or soil boring. The color change results from the reduction and oxidation of iron and manganese compounds in the soil after periodic saturation with water.

Drilled Well
- Drilled wells draw water from bedrock deep below the ground surface. As a well is drilled, steel casing is inserted into the hole, which is secured into the bedrock. Drilling continues deeper into bedrock until an adequate supply of water is discovered. Drilled wells are less vulnerable to surface contamination than springs or dug wells, but should still be protected.

Drop Inlet
- A structure that allows storm water to enter and pass downstream through the storm drainage system. Drop inlets are typically found at the edge of a road with curbing.

Dry Well - An underground structure that disposes of unwanted water, most commonly storm water runoff, by dissipating it into the ground, where it merges with the local groundwater.

E Coli - An abbreviation for Escherichia coli, which is a bacterial species that lives in the intestines of most warm-blooded mammals. High E. coli levels indicate a contamination of water caused by fecal matter from animals or humans. According to the Vermont Department of Health: "The presence of some fecal material in lakes, ponds and rivers is to be expected as part of the environment in which we live. As long as the level of fecal coliform bacteria is low, swimming is relatively safe."

Environmental Protection Agency (EPA) - The U.S. Environmental Protection Agency (EPA or sometimes USEPA) is an agency of the federal government of the United States charged to regulate chemicals and protect human health by safeguarding the natural environment: air, water, and land. The agency conducts environmental assessment, research, and education. It has the primary responsibility for setting and enforcing national standards under a variety of environmental laws, in consultation with state, tribal, and local governments.

Failure - Term commonly used in regulation to describe a system malfunction.

Geographic Information System (GIS) - An integrated collection of computer software and data used to view and manage information about geographic places, analyze spatial relationships, and model spatial processes. A GIS provides a framework for gathering and organizing spatial data and related information so that it can be displayed and analyzed.

Global Positioning System (GPS) -  A system of radio-emitting and -receiving satellites used for determining positions on the earth. The orbiting satellites transmit signals that allow a GPS receiver anywhere on earth to calculate its own location through trilateration.

Household Hazardous Waste - Common everyday products that people use in and around their homes including paint, paint thinner, herbicides, and pesticides that, due to their chemical nature, can be hazardous if not properly disposed.

Leach Field - An area of soil that serves as the physical location where final treatment and dispersal of effluent (or wastewater) occurs; effluent is usually distributed into a leach field using one or more perforated pipe laterals in gravel-filled trenches buried below the ground surface. Regulations dictate the size of a leach field based on the percolation rate of the soils and depths to seasonally high groundwater, bedrock, or other limiting conditions.

Malfunction - Condition in which a component is not performing as designed/installed. Surfacing sewer water (ponding) or spongy areas within a leach field are signs that a leach field is malfunctioning, and that the biomass in the soils has not degraded to allow the normal percolation of effluent into the ground for treatment.

Microbial Source Tracking (MST) - An approach, that uses one or a variety of methods & target organisms, to identify the sources of fecal pollution impacting a water system. Application of MST methods can provide identification of nonpoint sources of fecal pollution as well as an estimate of the relative contributions of different sources in the impacted area or under use-limiting conditions.

Non-point Source Pollution - Pollution that does not come from a single, identifiable source. Includes materials that wash from roofs, streets, yards, driveways, sidewalks and other land areas. Collectively, this is the largest source of stormwater pollution.

Non-public Water System - A drinking water supply and distribution system designed to supply drinking water to one or a cluster of properties that is privately owned and operated. In some cases, such as 9 lot-or-fewer subdivisions, these non-public systems require Water Supply Permits with ongoing operation and testing requirements, issued by the Vermont Agency of Natural Resources. In other cases, such as individual wells or springs serving individual homes, no ongoing monitoring is required by the state.

On-site Wastewater Treatment System - Wastewater treatment system relying on natural processes and/or mechanical components to collect and treat sewage from one or more dwellings, buildings, or structures and disperse the resulting effluent to subsurface soils on property owned by the same individual or entity. Often referred to as a "septic system",on-site systems are usually owned, operated, and managed by individual property owners. Vermont's small-scale wastewater system rules define such systems as "wastewater systems".

Outfall - Where a storm drainage system daylights to the surface, discharging the storm water that it collects. Outfalls typically daylight to swells, ravines, wetlands or the lake shore.

Pathogen - A pathogen is, most simply, a germ or biological agent that causes illness or disease to its host.

Percolation Rate - Measurement of the drop in water level in a boring as water moves into the surrounding soil material, typically expressed as minutes per inch.

Phosphorus - Phosphorus is an essential element that governs the rate of growth in plants and animals. In ecosystems, too much phosphorus can be problematic causing algae blooms, excessive plant growth and decay, and a reduction in water quality.

Point Source Pollution - Pollution from a single identifiable source such as a factory or a sewage-treatment plant. Most of this pollution is highly regulated at the state and local levels.

Public Community Water System - A drinking water supply and distribution system that is owned and operated by a public entity (such as a fire district or homeowner's association), and which provides drinking water to at least 15 properties or at least 25 year-round residents.

Replacement Area An area within a property that has been determined to be suitable for a replacement leach field in case an existing leach field fails or malfunctions.

Retention Pond - A storm water control device that collects storm water from a storm drainage system and retains it before discharge downstream to allow sediment to settle out. Retention ponds may be either a "dry type" where the pond is empty and dry after storm water treatment or "wet type" where the pond always retains some amount of water, even during dry conditions.

Ribotyping - A molecular (DNA) fingerprinting MST method used to differentiate between strains of a specific microorganism. It is often used with E. coli, and requires a reference library of fingerprints from humans and animal species that may be sources of fecal pollution. Thus, E. coli strains isolated from water samples are ribotyped and the resulting ribotype (DNA fingerprint) is then matched to ribotypes in the reference library to identify their source species (such as dogs, humans, deer, cows, geese, etc.).

Fluvial Geomorphology - A science which seeks to explain the physical interrelationships of flowing water and sediment in varying land forms.

Stream Geomorphic Assessment Tool (SGAT) - The tool that Vermont has developed for assessing stream geomorphic assessments.

Sediment - Soil particles that can be transported by fluid flow, and which eventually is deposited at the bottom of a water body.

Septic System - A commonly used term for an on-site wastewater treatment system.

Septic Tank - A water-tight, covered receptacle for treatment of sewage. The septic tank receives sewage from a building, separates settleable and floating solids from the liquid, digests organic matter, stores digested solids through a period of detention, allows clarified liquids to discharge for additional treatment and final dispersal, and attenuates flows.

Septic tanks should be pumped out periodically to remove the accumulated solids in the tank. Failure to do so will allow solids to collect to the point that the septic tank won't function properly, passing solids downstream to the leach field. This event is a primary cause of a leach field failure.

Shallow or dug Well
- A water supply source that draws water from shallow groundwater. Dug wells are created in a hand-dug excavation or by using excavating equipment, into which a concrete or brick casing is installed, typically about 6-8 feet deep. Driven well points, though they can be 20-30 feet deep, also draw water from the water table near the ground surface.

This type of water supply source, if not protected, can be vulnerable to contamination from land uses or surface conditions that surround the spring.

Spring - A water supply source flowing out of the earth where groundwater intersects the ground surface, which is dependent on gravity to move water from the source to the distribution system. This type of water supply source, if not protected, can be vulnerable to contamination from land uses or surface conditions that surround the spring. For more information on springs visit the Vermont Department of Health page.

Storm Drain System - A vast network of underground pipes and open channels designed for flood control.

Storm water - Water (rainfall, melting ice or snow) that is not absorbed in the ground. It runs over impervious surfaces and eventually ends up in our waterways.

Storm Water Pollution - As storm water runs over impervious surfaces, it picks up pollutant materials such as fertilizers, cigarette butts and pet waste along the way and runs into storm drains. Storm water is not treated before it is discharged into waterways in Chittenden County.

Subwatershed - A subunit of a watershed, often defined as the drainage area of a tributary of a watercourse.

Test pit - A hole dug into the ground, usually using a backhoe or excavator, entered by a licensed designer or engineer to determine soil characteristics, including soil texture and depth to groundwater or bedrock, for the purpose of determining an area's suitability for siting a leach field.

Wastewater - Wastewater is any water that is discharged into the sewer system by domestic residences, commercial properties, industry, or agriculture with potential contaminants. Unlike storm water, wastewater is treated before it is discharged into waterways in Chittenden County.

Watershed - A watershed is land that collects water and drains it into a river system or lake.

Wetlands - A wetland is a land whose soil is saturated with moisture either permanently or seasonally. Such areas may also be covered partially or completely by shallow pools of water. Wetlands include swamps, marshes, and bogs, among others. The water found in wetlands can be saltwater, freshwater, or brackish. Wetlands are considered the most biologically diverse of all ecosystems.