Vocabulary

Stormwater 101

Stormwater is water from precipitation that flows across the ground and pavement when it rains or when snow and ice melt. Stormwater eventually infiltrates through the ground (contributing to groundwater), runs directly into natural surface water features, evaporates or drains into systems of underground pipes or roadside ditches and may travel for many miles before being released into a lake, river, stream or wetland area.

A geologic formation through which virtually no water moves.

An underground layer of saturated sand, gravel, or rock that contains water in sufficient quantities to supply a well.

A test involving the withdrawal of measured quantities of water from a well and the measurement of resulting changes in head in the aquifer at various selected locations.

A saturated but poorly permeable formation that does not yield water freely to a well or a spring. However, an aquitard may transmit appreciable water to or from adjacent aquifers.

A well that penetrates through or into an impermeable layer of silt, clay, or rock. The water level in these wells rises above the upper surface of the aquifer due to the pressure in the confined aquifer. If the water pressure is great enough, the well will overflow the top of the land surface or well (flowing artesian).

Backflow is the unwanted flow of water in the reverse direction.

Back-siphonage is the flowing back of used, contaminated, or polluted water into a potable (drinking) water supply because of negative pressure in the pipe.

Back pressure is a force opposing the desired flow of water through pipes.

A general term for the consolidated (solid) rock that underlies soils or other unconsolidated surficial material.

A constructed barrier of compacted earth.

Describes ways to manage your land and activities to mitigate pollution of surface and groundwater near you.

The zone at the bottom of the vadose zone where groundwater is drawn upward by capillary force.

The surface and subsurface area surrounding a water well or wellfield which supplies a public water system, through which contaminants are reasonably likely to move toward and reach such water well or wellfield within a specified period of time.

The determination of the boundaries of the capture zone(s), typically delineated by complex computer groundwater flow programs, involving the input of numerous data, including water levels (heads), pumping volumes, aquifer thickness, transmissivities, recharge values and other aquifer characteristics.

A receptacle, located where a street gutter opens into a stormwater sewer, designed to retain matter that would not readily pass through the sewer.

The cone shaped area around a well where the groundwater level is lowered due to pumping. The shape of the cone is influenced by the underground porosity and water yield of the well.

Any physical, chemical, biological or radiological substance or matter that degrades water quality and/or threatens the safety of its intended use (i.e. drinking water). Some contaminants are only an aesthetic concern, while others are considered hazardous to your health.

A Cross Connection is an arrangement of pipes where undesirable water could flow backward into the potable (drinking) water system.

Pipe or concrete box structure which drains to open channels, swales, or ditches under a roadway or embankment typically with no catch basins or manholes along its length.

The reduction of head at a point caused by the withdrawal of groundwater. In other words, the distance between the static water level and the surface of the cone of depression.

A common process brought about by over fertilizing with excess phosphorus and nitrogen entering an aquatic system, creating overgrowth of aquatic plants, that then die off and get broken down by microorganisms that deplete the oxygen levels in the water.

An imaginary contour line on the water table or potentiometric surface showing an equal pressure head of groundwater in an aquifer. Normally, water flow is toward these lines.

The combined loss of water from an area through transpiration of plants and evaporation from soil or water.

A general term for unconsolidated sediment transported by glaciers and deposited directly on land or in the sea.

An approach to water management that stores, protects, and mimics natural systems and their ability to control and regulate water movement.

Water beneath the surface of the earth, which saturates the pores and fractures of sand, gravel and rock formations.

The rate of flow of water in gallons per day through a cross-section of one square foot under a unit hydraulic gradient (gpd/ft squared), at the prevailing temperature. See permeability.

The science dealing with the interrelationships of geologic materials and processes with subsurface waters and related geologic aspects of surface waters.

The continuous circulation of water between the earth and the atmosphere, involving condensation, precipitation, runoff, percolation, evaporation and transpiration.

The study of the occurrence, distribution and chemistry of all waters of the earth.

Any discharge into a storm drain that is not composed entirely of stormwater.

A hard surface area which either prevents or retards the entry of water into the soil mantle as under natural conditions prior to development; and/or a hard surface area which causes water to run off the surface in greater quantities or at an increased rate of flow from the flow present under natural conditions prior to development.

The downward flow of water through the pores or spaces of unsaturated rock or soil.

A well drilled and installed in a selected location for the purpose of collecting information regarding aquifer characteristics, such as geologic material, hydraulic parameters, water levels and water quality.

The part of the Clean Water Act which requires point source and non-point source dischargers to obtain permits for stormwater collection systems. In Michigan, these permits, referred to as NPDES permits, are administered by the Michigan Department of Environment, Great Lakes, and Energy (EGLE).

Contaminants found in water from a source that cannot be specifically defined. For example, contamination resulting from agricultural infiltration or runoff.

The capacity of rock or soil to transmit water. See "hydraulic conductivity."

Contaminants found in water that can be readily identified from a specific source such as a leaking underground storage tank.

Stormwater pollution can include chemicals, fast food wrappers, cigarette butts, Styrofoam cups, sewage overflow, cooking oil, bacteria from pet waste, used motor oil, fertilizers, paint and construction debris.

The spaces (voids) between particles of earth materials, such as clay, silt, sand, gravel, and rock. It is measured as the ratio of the volume of openings to the total given volume.

An imaginary surface representing the total head of groundwater in a confined aquifer, defined by the level to which water will rise in a well.

A ratio used to describe the proportion of one substance to another. In terms of time, 1 ppb is equal to one second in 32 years; also is equal to 1 drop in a 10,000-gallon tank. Also is measured as micrograms per Liter (ug/L).

A ratio used to describe the proportion of one substance to another. In terms of time, 1 ppm is equal to 1 minute in 2 years.

Rain, snow, sleet, or hail that falls to the ground as a part of the water cycle.

An area in which water reaches the zone of saturation from surface infiltration from precipitation, surface run-off, or groundwater underflow.

A specifically designed landscape planted with native flowers to help absorb, slow down, and retain stormwater runoff.

Land that runs adjacent or alongside a waterbody.

The portion of subsurface soil and rock where every available space is filled with water. Aquifers are located in this zone.

A condition in which untreated sewage is discharged from a sanitary sewer into the environment prior to reaching sewage treatment facilities. When caused by rainfall it is also known as wet weather overflow. Examples are blockage or broken of sewer lines, infiltration/inflow of excessive stormwater into sewer lines during heavy rainfall, malfunction of pumping station lifts or electrical power failure.

The level of water in a well that is not being affected by withdrawal of groundwater.

The volume of water an aquifer releases from or takes into storage per unit surface area of the aquifer per unit change in head.

Water that originates from precipitation and is a type of surface water created during abnormally large rain or snow falls.

It is stormwater running off, draining away and flowing over ground surfaces. It is created when rain falls or snowmelt run off roads, driveways, parking lots, rooftops and other paved or impervious surfaces that do not allow water to soak into the ground.

Water that collects on the ground surface from precipitation (oceans, streams, lakes, ponds, and other bodies of water found on the Earth's surface).

The rate at which water is transmitted through a unit width of an aquifer under a unit hydraulic gradient. Transmissivity values are typically given in gallons per day through a vertical section of an aquifer one foot wide and extending the full saturated height of an aquifer under a hydraulic gradient of 1 (gpd/ft).

The maximum amount of pollutants that a system can receive and still meet water quality standards.

An aquifer with the water table as its upper boundary. Because the aquifer is not under pressure the water level in a well is the same as the water table outside the well. An unconfined aquifer is usually near to the earth's surface causing it to be easily recharged - but contaminated as well.

An area, usually between the land surface and the water table, where the openings or pores in the soil contain both air and water.

The zone containing water under pressure less than that of the atmosphere, including soil water, intermediate vadose water, and capillary water. This zone is limited above by the land surface and below by the surface of the zone of saturation (water table).

All land and water within a drainage area, defined by topographic high points.

The top of an unconfined aquifer where water pressure is equal to atmospheric pressure; in other words, the surface between the zone of saturation and the zone of aeration. The water table depth fluctuates with climate conditions on the land surface above and is usually gently curved and follows a subdued version of the land surface topography.

A surface and subsurface land area regulated to prevent contamination of a well or well-field supplying a public water system.

An area inundated or saturated by ground or surface water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.

This project has been funded wholly or in part by a grant through the Watershed Council Support Program by the Michigan Department of Environment, Great Lakes, and Energy's Nonpoint Source Program to Kalamazoo Stormwater Working Group for the Multilingual Outreach and Education project. The contents of the document do not necessarily reflect the views and policies of the Department of Environment, Great Lakes, and Energy, nor does the mention of trade names or commercial products constitute endorsement or recommendation for use.

Este proyecto ha sido financiado en su totalidad o en parte por una subvención a través del Programa de Apoyo del Consejo de Cuencas Hidrográficas del Departamento de Medio Ambiente, Grandes Lagos y Energía de Michigan, Programa de Fuentes No Puntuales para el Grupo de Trabajo de Aguas Pluviales de Kalamazoo para el proyecto de Educación y Alcance Multilingüe. El contenido del documento no refleja necesariamente los puntos de vista y las políticas del Departamento de Medio Ambiente, Grandes Lagos y Energía, ni la mención de nombres comerciales o productos comerciales constituye respaldo o recomendación para su uso.