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V W X Y
American Association of State Highway and Transportation Officials
shaft: vertical work shaft used to access subsurface tunneling operations.
The shaft allows removal of excavated materials and the installation of
building: a detached building whose purpose is related to, but subordinate
to, that of the principal building on a given parcel of land.
acid rain: rain with a pH of less than 5.6 that has mixed with sulfur
and nitrogen oxides in the atmosphere as a result of burning fossil fuel.
Acid rain can damage buildings, wildlife and aquatic life.
a volume of water one foot deep and one acre in area, or 43,560 cubic
a process used in wastewater treatment that promotes biological degradation
of organic matter in water. The process can be passive (waste is exposed
to air), or active (a mixing or bubbling device introduces oxygen).
tank: a chamber used to inject oxygen into wastewater during treatment.
describes the visual quality of buildings and spaces within a townscape.
the process a municipality acquires surrounding land and incorporates
it into its jurisdiction.
American Society of Testing and Materials
flow: the portion of stream flow that is not due to runoff from precipitation,
usually supported by water seepage from natural storage areas such as
aquifers, lakes, or wetlands.
a structure, located above or below ground, that temporarily stores storm
water, wastewater or combined sewage. Combined sewage basins generally
hold the flow until the sewer system has sufficient capacity to transport
it to the treatment plant. Many basins are equipped with treatment devices
should primary treatment and disinfection be necessary. (Also, see storm
water retention basins.)
filter press: equipment that reduces the water content of solids removed
during the wastewater treatment process. These solids (called sludge)
are easier and less costly to haul and dispose of when water content is
Management Practice (BMP): a practice or combination of practices
that prevents or reduces storm water runoff and/or associated pollutants.
Oxygen Demand (BOD): a laboratory measurement of wastewater that is
one of the main indicators of the quantity of pollutants present. BOD
measures the amount of oxygen that will be consumed by microorganisms
when oxygen in wastewater biologically reacts with organic material in
the wastewater. A decrease in BOD indicates that water quality is improving.
bioengineering: the science that uses living plant materials as a main
structural component to control erosion, sedimentation, and flooding.
Also referred to as soil bioengineering, it is used for land stabilization
and habitat restoration.
unsightly condition including the accumulation of debris, litter, rubbish,
or rubble; fences characterized by holes, breaks, rot, crumbling, cracking,
peeling or rusting; landscaping that is dead, characterized by uncontrolled
growth or lack of maintenance, or damage, and any other similar conditions
of disrepair and deterioration regardless of the condition of other properties
in the neighborhood.
cylindrical samples of a soil profile used to estimate the load-carrying
capacity of the soil or determine infiltration capacity.
abandoned, idled, or underused industrial and commercial facilities where
expansion or redevelopment is complicated by real or perceived environmental
a strip of land , fence, or border of trees between one use area and another.
Improvement Program (CIP): a program that spaces projects over several
years, allowing municipalities to stay within their debt limit.
mortar or concrete that is deposited in the place where it is required to
harden as part of the structure, as opposed to precast concrete.
basin: a below-ground structure designed to collect and convey water
into the storm sewer system. The design allows sediment to fall to the
bottom of the catch basin and not directly into the pipe.
Business District (CBD): the major commercial downtown center of a
dam: a log or earthen structure used in swales to reduce water velocities,
promote sediment deposition and enhance infiltration.
the process of disinfecting treatment plant effluent by mixing with chlorine.
cistern: an underground tank or pipe to collect storm water runoff from
catch basins prior to discharge into sewer systems. Cisterns are used
to store and slowly release storm water from residential areas into the
combined sewer system until the threat of CSOs has passed.
Water Act (CWA): the Clean Water Act is a 1977 amendment to the Federal
Water Pollution Control Act of 1972 which set the basic structure for
regulating discharges of pollutants to waters in the United States. The
law gave the EPA authority to set effluent standards on an industry basis
and continued the requirements to set water quality standards for all
contaminants in surface waters. The CWA makes it unlawful to discharge
any pollutant into a navigable water unless a NPDES permit is obtained
under the Act. The CWA was reauthorized in 1987. The reauthorization focused
on toxic substances, authorized citizen suit provisions and funded sewage
plants under the Construction Grants Program.
development: a development approach where buildings are grouped in
close proximity and the remaining land is used as open space and recreational
aggregates and liquid bitumin mixed up by hand or plant and stockpiled
for patching or maintenance.
system: a network of sewer pipes used to collect wastewater and/or
storm water and transport it to a wastewater treatment plant or sewer
sewers: pipes that run under city streets and receive sewage from
homes and businesses. Collector sewers connect directly to an interceptor
sewer that carries the wastewater to a treatment facility.
sewer: a sewer system that carries both sewage and storm water runoff.
Normally, its entire flow goes to a wastewater treatment plant, but during
a heavy storm, the volume of water may be great enough to cause overflows
of untreated mixtures of storm water and sewage into receiving waters.
Storm water runoff may also carry toxic chemicals from industrial areas
or streets into the sewer system.
sewer overflow (CS0): discharge of a mixture of storm water and sewage
when the flow capacity of a sewer system is exceeded during rainstorms.
the mixing of flows from two different sources. An example would be discharging
sanitary sewer flows into a combined sewer system.
use permit: a permit issued by the city or city and county planning
commissions stating that the conditional use complies with the conditions
and standards set forth in this title and authorized by the planning commission.
Decree: a legal document, approved by a judge, that formalizes an
agreement reached between EPA and potentially responsible parties (PRPs)
through which PRPs will cease or correct actions or processes that are
polluting the environment. The Consent Decree describes the actions PRPs
will take and may be subject to a public comment period.
structure: a structure such as a weir, gate or regulator located at
a point in a sewer where flows can be detained or diverted in a different
direction to prevent sewer pipes from becoming overloaded.
feet per second (cfs): a unit of measure for the rate of liquid flow
past a given point equal to one cubic foot in one second. 1 cfs is equal
to 1.547 million gallons per day.
culvert: a closed conduit used for the passage of surface water under a road or
decanting/dewatering: the process of draining or removing water from
a storage structure like a basin or tunnel after a storm.
the process of removing residual chlorine from wastewater treatment plant
effluent that has been disinfected with chlorine.
the study of population and its characteristics, including its age structure,
spatial distribution, growth patterns, social and economic characteristics,
and ethnic composition.
the number of dwelling units per acre.
storm: a rainfall event of specified size and return frequency (e.g.
a storm that occurs only once every two years) that is used to calculate
the runoff volume and peak discharge rate to a BMP.
the registered engineer representing a firm, association, partnership,
corporation or any combination of these who is responsible for the supervision
or preparation of plans and specifications associated with storm drainage
the temporary storage of storm water runoff to control peak discharge
rates and provide gravity settling of pollutants.
time: the amount of time that a volume of water will remain in a detention
a porous tube or other device that air is forced through and divided into
very small bubbles for interaction with organic pollutants found in liquids.
the rate of flow (the volume of water passing a point in a given period
of time). Usually expressed as cubic feet per second.
a chemical or physical process that kills pathogenic organisms in water.
Chlorine is often used to disinfect sewage treatment effluent, water supplies,
wells, and swimming pools. Ultraviolet radiation is another disinfecting
process used in wastewater treatment.
Oxygen (DO): the oxygen freely available in water, vital to fish and
other aquatic life and for the prevention of odors. DO levels are considered
the most important indicator of a water body's ability to support desirable
aquatic life. Secondary and advanced waste treatment are generally designed
to ensure adequate DO in waste-receiving waters.
downspout disconnection: downspouts are connected into many combined
sewer systems increasing the amount of rain water that gets into a system.
Downspouts are disconnected at ground level to divert rain water onto
lawns where it will filter into the ground. This requires capping the
existing outlet pipe, installing a concrete splash pad at the downspout
outlet and diverting the flow away from the home or building.
area: the area of a watershed usually expressed in square miles or
the gradual reduction in water level in a storm water basin due to the
combined effect of infiltration and evaporation.
dry weather flow: flow in a combined or sanitary sewer that is not influenced
by a rain storm or snowmelt.
a legal right, granted by a property owner to another entity, allowing
that entity to make limited use of the property involved for a specific
purpose. The Drain Commissioner secures temporary and permanent easements
adjacent to County Drains to provide construction and maintenance access.
Easements are recorded on the title to the land and transfer with the
sale of land.
wastewater (treated or untreated) that flows out of a treatment plant,
sewer, or industrial outfall into a surface water.
limitation: restrictions established by a State or EPA on quantities,
rates, and concentrations in wastewater discharges.
enclosed storm drainage system: a system of buried sewer pipes to collect
and transport storm water to an outlet on a river, stream or lake. Most
urban areas have enclosed storm drainage systems.
Commissioner: storm sewers which have been designated to be under
the jurisdiction of the Drain Commissioner.
storm sewers located outside of road rights-of-way for which the municipality
has jurisdiction unless specific jurisdiction is designated by the Drain
Commissioner, WCDPS, or MDOT.
assessment: a review process for proposed federal, federally funded
or federally licensed or sponsored projects or actions. An environmental
assessment determines whether an action or project is environmentally
significant and whether an environmental impact statement (EIS) must be
detention control device: a pipe or series of pipes that extend from
the riser of a storm water pond that are used to gradually release storm
water from the pond over a 24 - 40 hour period.
added earth which is designed to change the contour of the land.
fabric: textile of relatively small mesh or pore size that is used
to 1) allow water to pass through while keeping sediment out (permeable)
or 2) prevent both runoff and sediment from passing through (impermeable).
strip: area of land covered with vegetation that slows and filters
flows when depths are shallower than the vegetation height.
flush: the delivery of a highly concentrated pollutant loading during
the early stages of a storm, due to the washing effect of runoff on pollutants
that have accumulated on the land.
floatables: materials found in sewers and storage tanks that are lighter
for a given flood event, that area of land adjoining a continuous watercourse
that has been covered temporarily by water.
gates: devices (gates) in a sewer or tank that can store flow. The
flow is then released to flush sediments deposited in sewer and tank sections
below the gates.
footing drain: drain tiles around a home’s foundation that collect
water from around the home and prevent it from leaking into the basement.
footing drain disconnection: the removal of storm water footing drain
flow from a combined or sanitary sewer system. This typically requires
the installation of a sump pump to direct flows onto a lawn or into a
nearby storm sewer system.
the space from the top of an embankment to the highest water elevation
expected for the largest design storm to be stored. The space is required
as a safety margin in a pond or basin. A minimum of one foot is required.
flooding: a phenomenon in urban streams whereby the number of bankfull
and sub-bankfull flood events increases sharply after development. The
frequency of these disruptive floods is a direct function of watershed
wetland: narrow emergent wetland areas that are created by the use
of shallow underwater benches along the perimeter of a wet pond. The benches
are usually 15 feet wide and up to 12 inches deep. The fringe wetlands
enhance pond pollutant removal, conceal trash and water level changes,
reduce safety hazard, and create a more natural appearance.
a moveable, water tight barrier used inside a sewer to control the movement
or direction of wastewater flow.
the long-term ideal or end product that is desired.
a linear park, alternative transportation route, or open space conservation
area approved by the metro greenways commission that provides passive
recreational opportunities, pedestrian and/or bicycle paths, and/or the
conservation of open spaces or natural areas, as indicated in a greenway
plan adopted by the commission.
floor area: the sum of the area of all of a building's floors existing
within its exterior walls. A municipal zoning ordinance may define gross
floor area as extending to the outer surface of the exterior walls; in
commercial leasing, however, gross floor area is measured to the inside
finish of these walls.
a designated street route construction equipment follows when
going to or leaving a construction site. Usually, main roads with a direct
route to an expressway are selected for the haul route.
heavy metals: metals that can be precipitated by hydrogen sulfide in
acid solution, including lead, silver, gold, mercury, bismuth, and copper.
Heavy metals are considered harmful to humans when ingested.
occupation: commercial activity within an individual's dwelling. Several
approaches may be taken by municipalities attempting to define which home
occupations are to be permitted and are least likely to have an adverse
impact upon the residential neighborhood.
modeling: development of a computer model to represent the flow of
wastewater in a collection system to determine how the system will react
under different flow conditions.
the branch of engineering that deals with water or other fluid in motion.
a graph showing variation in the water depth or discharge in a stream
or channel, over time, at a specific point along a stream.
the applied science concerned with the waters of the earth in all their
states - their occurrence, distribution, and circulation through the unending
hydrologic cycle of precipitation, consequent runoff, streamflow, infiltration,
and storage, eventual evaporation, and reprecipitation. It is concerned
with the physical, chemical, and physiological reactions of water with
the rest of the earth and its relation to the life of the earth.
illicit connection: an illegal connection of a sanitary sewer into a storm
sewer that allows human waste to go directly into streams and rivers.
Illegal connections also include illegal storm water connections to sanitary
systems, such as sump pumps that homeowners have connected into the sanitary
sewer system instead of discharging into their yard or storm sewer.
Illicit Discharge Elimination Plan (IDEP): a plan required by the USEPA's
NPDES Permit Program to eliminate illegal, untreated sanitary discharges
into surface and ground waters.
impervious areas: surfaces that cannot absorb rain water including streets,
sidewalks, roofs, parking lots and driveways. The larger the impervious
area, the greater the runoff volume.
1) the absorption of water into the ground, expressed in terms of inches/hour.
2) the penetration of water from the soil into sewer or other pipes through
defective joints, connections, or manhole walls.
the discharge of storm water to a sanitary sewer system via footing drains,
sump pumps, inappropriate catch basin connections, leaking manhole covers
or other sources.
flows into a treatment facility, storage facility, or sewer system. Influent
characteristics, flow rates and volume are used to determine the size
and treatment requirements of a facility.
in-system storage: the use of existing sewer pipes and structures to
store excess flows during a wet weather event.
sewers: large sewer lines that, in a combined system, control the
flow of sewage to the treatment plant. In a storm, they allow some of
the sewage to flow directly into a receiving stream, thus keeping it from
overflowing onto the streets. Also used in separate systems to collect
flows from trunk sewers and carry them to treatment plants.
the interior surface of the bottom of any pipe.
the various ways in which land may be employed or occupied. Planners
compile, classify, study and analyze land use data for many purposes,
including the identification of trends, the forecasting of space and infrastructure
requirements, the provision of adequate land area for necessary types
of land use, and the development or revision of comprehensive plans and
land use regulations.
land use plan:
a proposal for how land should be used and where growth
and renewal should occur. The land use plan, often one element of a comprehensive
plan, is frequently developed concurrently with other closely related
documents, such as transportation plans, environmental plans and community
facility plans. Land use plans often cover a 20- to 25-year time span.
lateral sewer: a sewer that collects flows from homes and businesses
for discharge into trunk sewers.
the proportion of the surface of a lot that is covered by buildings or
that the municipal ordinance permits to be covered by buildings.
a concrete structure on a gravity sewer to permit entry for servicing.
Manning's Roughness Coefficient ("n"):
a coefficient used in Manning's Equation
to describe the resistance to flow due to the roughness of a culvert or
the average obtained by adding together the sum of the values and dividing
by the number of values.
the value that appears at the midpoint of a distribution and divides the
distribution in half.
Metropolitan Planning Organization (MPO):
a local governmental unit that has legal
jurisdiction over a geographic area for government service planning such
as transportation and land-use planning.
million gallons per day (mgd):
a measurement of water flow. It represents the number of million gallon
increments of volume passing by a stationary point in a 24-hour period.
Million gallons is abbreviated as MG.
an activity or project to reduce the impact of a pollutant
or replace lost land features such as wetlands and surface water.
Mixed-Use Development (MXD):
a project in which a variety of complementary land
uses are planned and constructed in one coordinated development. Typical
mixed-use projects have office towers, street-level retail areas or malls,
parking structures, and a subway and/or bus station at their base. Some
have a hotel, theater or park as well.
modified county drains:
open channels that have been designated as a County
Drain and a major channel modification or relocation, widening or deepening
has occurred under the jurisdiction of the Drain Commissioner.
a temporary prohibition on new construction, usually imposed by government
as a response to rapid growth that threatens to exhaust the water and
sewer system or that is inadequately controlled by local land-use regulations.
National Pollutant Discharge Elimination System (NPDES):
a provision of the
Clean Water Act that prohibits discharge of pollutants into waters of
the United States unless a special permit is issued by EPA, a state, or,
where delegated, a tribal government on an Indian reservation.
a zone where plantings capable of filtering storm water are
preserved or established and where construction paving or chemical application
natural county drains:
drains that are designated as a County Drain where
maintenance/cleanout operations have been performed under the jurisdiction
of the Drain Commissioner.
open channel sections of natural origin that have not
been designated as a County Drain.
an approach to land-use planning and urban design that
promotes the building of neighborhoods with a mix of uses and housing
types, architectural variety, a central public gathering place, interconnecting
streets and alleys, and edges defined by greenbelts or boulevards.
net floor area:
the total floor area of a structure minus the square footage
devoted to elevator shafts, stairwells, interior space used for parking
or loading, equipment and utility rooms and most basement areas.
the process of reintegrating the components of modern life - housing,
workplace, shopping and recreation - into compact, pedestrian-friendly,
mixed-use neighborhoods linked by transit and set in a larger regional
open space framework.
any nonconforming aspect of a structure, land, or use.
non-point source: sources of pollution that cannot always be traced to
an exact point of entry. Non-point sources of pollution include land runoff
that goes directly in the river, illicit sanitary sewer connections to
a storm sewer and streambank erosion.
an element or compound such as nitrogen, phosphorus or potassium
that is necessary for plant growth. Fertilizers contain nutrients.
detention provided at a regional detention facility as
opposed to storage on-site.
one hundred year flood (100-year flood):
a surface water flood elevation
that has a 1% chance of occurring in any given year.
one-year, one-hour storm:
the intensity of a storm that statistically occurs
at least once every year is called the 1-year, 24-hour storm. The 1-year,
1-hour storm is the hour during that storm with the heaviest rainfall.
open cut construction method:
a method of construction where a large trench
is cut to place a sewer or water main pipe.
open drainage system:
a system of ditches and open channels that collect
and transport storm water to an outlet on a river or stream. Open drainage
systems are typically found in rural and industrial areas.
a law, rule or regulation issued by the governing body of a local municipality
under legal authority granted by the state. Ordinances are limited to
the area over which the local governing body has jurisdiction.
material derived from organic or living things.
an opening in a wall or plate.
the conduit through which effluent is discharged into receiving waters.
the flow of storm water across the land surface that ultimately
reaches a stream, river or lake.
additional zoning requirements that are superimposed upon
existing zoning in specified areas shown on a zoning map. Overlay zones
are commonly used when an area requires special protection or has a special
a loop formed by a horseshoe-shaped bend in a river.
the maximum instantaneous rate of flow during a storm,
usually in reference to a specific design storm event.
an authorization, license, or equivalent control document issued by an
approved State agency to implement the requirements of an environmental
regulation (e.g. a permit to operate a wastewater treatment plant or to
operate a facility that may generate harmful emissions).
issuing authority: the State agency issuing NPDES or other environmental
permits to regulated facilities.
surfaces that are permeable and absorb storm water.
Grass is a pervious surface.
a legal request to the Drain Commissioner to perform maintenance or construction,
or to set up a drainage district. Either the municipality or individual(s)
can petition to have work done or a district set up.
filtration: separation of particulate pollutants from storm water
runoff as they pass across or through a surface of grass, or other organic
pilot project: a project conducted on a small scale to demonstrate the
effectiveness of an approach, such as to treat wet weather pollution or
limit storm water from getting into a collection system.
Unit Development (PUD): development characterized by comprehensive
planning for the project as a whole, clustering of structures to preserve
usable open space and other natural features, a mixture of housing types
and sometimes a variety of nonresidential uses as well.
wetlands: a storm water wetland design adapted for small drainage
areas with no reliable source of base flow. The surface area of pocket
wetlands is usually less than a tenth of an acre. The pocket wetland usually
has no deep water cells, and is intended to provide some pollutant removal
for very small development sites.
point source: discharges from stationary locations such as WWTPs, storm
sewer outlets and factories. Point source discharges include combined
sewer outfalls and storm sewer outfalls.
generally, any substance introduced into the environment that adversely
affects the usefulness of a resource.
generally, the presence of matter or energy whose nature, location, or
quantity produces undesired environmental effects. Under the Clean Water
Act, for example, the term is defined as the manmade or man-induced alteration
of the physical, biological, chemical, and radiological integrity of water.
system: a two-cell storm water wetland design that uses a wet pond
in combination with a shallow marsh. The pond/wetland design saves space
and has been shown to be very effective at removing urban pollutants.
techniques to reduce/minimize pollutants prior to treatment facilities.
In storm water, typically associated with detention basin forebays designed
to capture or trap coarse sediments to preserve storage and prevent clogging.
In wastewater, usually associated with industrial/commercial sites intended
to reduce their discharge pollutant concentrations to levels that can
be accommodated by a municipal wastewater treatment facility.
primary treatment: the first major treatment process in a wastewater treatment
facility where solids and liquids are separated. This is usually done
through a settling process where the materials that float or settle are
removed. Primary treatment removes about 30% of pollutants from domestic
any person or agent representing a firm, association, partnership, corporation,
or any combination of these who proposes to undertake to modify or locate
any structure within an identified storm drainage facility.
a structure containing pumps and the associated piping, valves
and other mechanical and electrical equipment for lifting wastewater to
a higher level.
Rational Method Formula:
a simple technique for estimating peak discharge rates
for developments, based on the rainfall intensity, watershed time of concentration,
and a runoff coefficient. If a development is less than one square mile
in area the formula is Q=CIA.
wetland: any wetland protected by state law or local government regulation.
regulator: a device installed in combined systems to control the amount
of flow into the sewer system during periods of wet weather. Excess flows
are routed to an outfall.
the rate of discharge from a detention facility in volume per unit time.
a sewer built parallel to an existing sewer to carry a portion
of the area's flow because the existing sewer is not large enough to transport
return interval: a statistical term for the average time of expected interval
that an event of some kind will occur (e.g. a storm water flow that occurs
every 2 years).
a modification of, or amendment to, the zoning ordinance.
a combination of large stone, cobbles, and boulders used to line channels,
stabilize banks, reduce runoff velocities, or filter out sediment.
a vertical pipe or weir within the embankment of a storm water wetland
that is used to regulate the storm water discharge from the structure
for specified design storm(s).
the excess portion of precipitation that does not infiltrate into the
ground, but "runs off" and reaches a stream, water body, or storm sewer.
the ratio of the amount of water that is NOT absorbed by the surface to
the total amount of water that falls during a rainstorm.
methods for safely conveying storm water to a wetland
to minimize disruption of the stream network and promote infiltration
or filtering of the runoff.
ratio: the surface area to volume ratio is a useful measure of the
capacity of a storm water wetland to remove pollutants via sedimentation,
adsorption, and microbial activity. The SA/V ratio can be increased by
either increasing the surface area of a wetland or increasing the internal
structural complexity within the wetland.
underground pipes that carry only domestic or industrial waste, not storm water.
sanitary sewer overflow (SSO): discharge of sewage when the flow capacity of
a sanitary sewer system is exceeded.
removal of sand or earth from the bottom or banks of a river by the erosive
action of flowing water. Erosion of a concrete surface, exposing the aggregate.
The action of a flowing liquid as it lifts and carries away the material
on the sides or bottom of a waterway, conduit, or pipeline. The enlargement
of a flow section of a waterway through the action of the fluid in motion
carrying away the material composing the boundary.
use of screens to remove coarse floating and suspended solids from sewage.
treatment: the second major step in the wastewater treatment process
where bacteria consume the organic parts of the waste. It is accomplished
by bringing together waste, bacteria, and oxygen in trickling filters
or in the activated sludge process. This treatment removes floating and
settleable solids and when combined with primary treatment about 90% of
the oxygen-demanding substances and suspended solids. Sludge disposal
is included and disinfection is the final stage of secondary treatment.
forebay: storm water design feature that employs the use of a small,
separate cell pool to settle out incoming sediments before they are delivered
to a storm water wetland. The forebay is typically 10% in excess of the
total treatment volume of a BMP.
septic system: a domestic wastewater treatment system that treats household
waste through a septic tank and a soil absorption system. Bacteria decomposes
the waste, sludge settles to the bottom of the tank, and treated effluent
flows out into the ground through drainage pipes. Failing septic systems
can contaminate ditches, creeks and shallow drinking water supplies.
the required distance between every structure and the lot lines of the
lot on which it is located.
settling: the process of subsidence and deposition of suspended matter
carried by water, wastewater, or other liquids. It is usually accomplished
by reducing the velocity of the liquid below the point that it can transport
the suspended material. Also called sedimentation.
tank: a holding area for wastewater, where heavier particles sink
to the bottom for removal and disposal.
the waste and wastewater produced by residential, commercial and industrial
sources and discharged into sewers.
a channel or conduit that carries wastewater and storm water runoff from
the source to a treatment plant or receiving stream. "Sanitary" sewers
carry household, industrial, and commercial waste. "Storm" sewers carry
runoff from rain or snow. "Combined" sewers handle both. Sewers are also
categorized by the flow they carry, e.g. collector, interceptor and trunk.
sewer separation: replacing a combined sewer with a separate sanitary
sewer pipe and a storm sewer pipe. The sanitary sewer pipe flow is transported
to a wastewater treatment plant and storm sewer flow is discharged directly
to a drain or river, without treatment.
runoff which flows over the ground surface as a thin, even layer, not
concentrated in a channel.
circuiting: the passage of runoff through a BMP in less than the theoretical
or design treatment time.
shunt channel: a channel used to route flows around a storage basin when
flow rates result in negative treatment.
plan: an accurately scaled development plan that illustrates the existing
conditions on a land parcel as well as depicting details of a proposed
development. Among the features generally required on a site plan are
the property boundaries and lot lines; major features of the landscape;
and proposed street and utility networks, as well as planned access points.
skimming: the removal of floatables from combined or sanitary sewage.
the accumulated solids separated during primary and secondary treatment.
It is disposed of through incineration or land application.
cake: sludge that has been dewatered to a semi-solid mass.
runoff created when snow melts and the resulting water enters sewer systems.
sodium hypochlorite: a water solution of sodium hydroxide and chlorine
where sodium hypochlorite is the essential ingredient. It is similar to
laundry bleach and is used as a disinfectant in CSO basins.
soft engineering: is the use of ecological principles and practices
to reduce erosion and achieve the stabilization and safety of shorelines, while
enhancing habitat, improving aesthetics, and saving money.
Special Flood Hazard Area (SFHA): areas inundated by a flood having a one
percent probability of being equaled or exceeded in any given year (also
referred to as the 100-year flood).
a depression in the embankment of a pond or basin, used to pass peak discharges
in excess of the design storm.
zoning: the assignment of a zoning classification different from the
surrounding zoning classifications to a relatively small land parcel.
Illegal spot zoning occurs when the use classification benefits the proprietor
and is in violation of the community's comprehensive plan. Legal spot
zoning includes new flexible zoning techniques (such as floating zones)
or special zoning districts (such as historic districts).
Revolving Fund (SRF) loan: a federal and state program offering low
interest loans to municipalities for the construction of publicly-owned
water pollution control facilities.
temporary holding of wastewater before treatment, as in tunnels, basins
drainage system: consists of any component and associated appurtenances
which convey surface storm water runoff and include overland (street)
drainage swales, street gutters, ditches, watercourse, drains, rivers,
streams, various types of culvert and storm sewer enclosures, diversions,
levees, and detention facilities. Stream - By MDNR definition: "a river,
creek, or surface waterway that may or may not be defined by Act 40, P.A.
of 1956; has definite banks, a bed, and visible evidence of continued
flow or continued occurrence of water, including the connecting water
of the Great Lakes." Even if water flow is intermittent, it is classified
as a stream.
sewer: a system of pipes (separate from sanitary sewers) that carries
only storm water runoff from buildings and land surfaces.
water detention basin: a constructed basin that temporarily stores
water before discharging into a surface water body. Can be classified
into three groups:
wetland: a conventional wetland which uses a variety of depths to
create conditions suitable for the growth of wetland plants. These constructed
systems are not located within natural delineated wetlands.
detention basin: a detention basin that has been modified to increase
the length of time that storm water will be detained to between 24 -
40 hours. Not effective at removing nutrients such as phosphorus and
nitrogen, unless a shallow marsh is incorporated into the lower stage
of the design.
detention basin: a detention basin that contains a permanent pool
of water that will effectively remove nutrients in addition to other
pollutants. This method is preferred in Canton Township.
water influenced wetland: refers to a natural wetland in an urban
area that receives urban storm water runoff.
storm water runoff: water that runs off streets, roofs and land during
rain storms, washing pollutants off these surfaces into the sewer system.
Typical pollutants of storm water runoff include chlorides, coliform bacteria,
heavy metals, nutrients, oil and grease, and suspended solids.
water wetland: a conventional storm water wetland is a shallow pool
that creates growing conditions suitable for the growth of marsh plants.
Storm water wetlands are designed to maximize pollutant removal through
wetland uptake, retention, and settling. These constructed systems are
typically not located within delineated natural wetlands.
stream bank erosion: the movement of sediment and soil material from
the banks and bottom within a stream or river. The higher the flow, the
greater the erosion.
refers to all the elements that constitute the physical makeup of a street
or avenue and that, as a group, delineate its character. A streetscape
includes building frontage, street paving and furniture, street tree planting,
lighting and signage.
the lower portion of a structure forming the foundation that supports
the superstructure of a building.
a drainage area within a watershed.
exaggerated tilt of roadway on a curve to counteract centrifugal force
that part of a bridge above the bridge seats, above the spring line of
the arches or above the bottom of the caps. That part of a building or
other structure which is carried upon any main supporting level, as a
Control and Data Acquisition (SCADA): a system used to electronically
monitor (including the ability to trend data and generate regulatory reports)
and control remote operations from a central point. For example, SCADA
can be used to control and monitor the status of a remote pumping facility
from a water or wastewater facility. A SCADA system consists of five major
components: master computer, software, communication link, remote terminal
and input/output devices. The key component is the communication link
that can be dial up telephone, cellular telephone or radio frequency.
Additional equipment is chosen based on compatibility with the communication
suspended solids: solid organic or inorganic particles physically held
in suspension in wastewater by agitation or flow.
a channel or a sloped surface that directs the flow of storm water runoff.
Swales can be vegetated, lined with vegetation that slows and filters
flows when depths are shallower than the vegetative height, or paved.
swirl concentrator: a treatment device that uses centrifugal force to
remove pollutants from wastewater.
occurs when the government acquires property or an interest in property
from a private owner or otherwise substantially diminishes the value of
property or substantially deprives the owner of the use and enjoyment
of his property.
financing: a means of financing redevelopment projects in which an
area is improved with the proceeds of a bond issue slated to be repaid
by the additional taxes the new development is expected to generate.
one-hour storm: the intensity of a storm that statistically occurs
at least once every ten years for a 24-hour period. The 10-year, 1-hour
storm is the hour during that storm with the heaviest rainfall.
of concentration: the time it takes for surface runoff to travel from
the hydraulically farthest portion of the watershed to the design point.
of Developmental Rights (TDR): the transfer of the development potential
of one piece of property to another.
wastewater: wastewater that has been subjected to one or more physical,
chemical, and biological processes to reduce its pollution.
plant: a structure built to treat wastewater before discharging it
into the environment.
sewer: a sewer that receives wastewater from many areas.
a large, underground structure used to store and transport wastewater,
combined sewage or storm water during rain storms. Tunnels usually have
higher storage capacities than basins and are capable of transporting
their flows directly to a wastewater treatment plant.
boring machine: a machine used to drill through the ground to create
construction method: an underground construction method where a tunnel
boring or mining machine is used to drill a passageway for a tunnel pipe.
Construction activities are conducted through an access shaft.
(UV) disinfection: the process of using ultraviolet radiation to disinfect
wastewater treatment plant effluent. UV disinfection is an alternative
plastic pipes with holes drilled through the bottom, installed on the
bottom of an infiltration BMP to collect and remove excess runoff.
design: the attempt to give form, in terms of both beauty and function,
to selected urban areas or to whole cities.
The United States Environmental Protection Agency is the federal regulator
responsible for administering the Clean Water Act.
engineering: an independent review of project concepts and designs
with the purpose of identifying opportunities to enhance the value of
the project by systematically evaluating the project's functions and ways
to achieve the functions at the lowest total cost.
spent or used water from a home, community, or industry that contains
dissolved or suspended matter.
collection system: a system of underground sewer pipes that collect
wastewater from households and businesses and convey it to a wastewater
treatment plant. Sometimes these pipes also collect storm water, called
combined systems. Pump stations and control structures are considered
part of the collection system.
infrastructure: the plan or network for the collection, treatment,
and disposal of sewage in a community. The level of treatment depends
on the size of the community, the type of discharge, and/or the designated
use of the receiving water.
operations and maintenance: actions taken after construction to assure
that facilities constructed to treat wastewater will be operated, maintained,
and managed to reach prescribed effluent levels in an optimum manner.
treatment plant (WWTP): a facility containing a series of tanks, screens,
filters and other processes used to remove pollutants from wastewater.
pollution: the presence in water of enough harmful or objectionable
material to damage the water's quality.
quality criteria: levels of water quality expected to render a body
of water suitable for its designated use. Criteria are based on specific
levels of pollutants that would make the water harmful if used for drinking,
swimming, farming, fish production, or industrial processes.
state-adopted and EPA-approved ambient standards for water bodies. The
standards prescribe the use of the water body and establish the water
quality criteria that must be met to protect designated uses.
the complete area or region draining into a river, river system, or body
a structure that extends across the width of a channel and is used to
impound, measure, or in some way alter the flow of water through the channel.
a conventional wet pond has a permanent pool of water for treating incoming
storm water runoff.
wet sanitary system: a sanitary sewer system that experiences a higher
volume of flow during wet weather due to storm water inflow and infiltration.
weather: weather that creates precipitation including rain, snow,
sleet and hail.
wet weather pollution: pollution that occurs as the result of storm water
entering a sewer system or running off impervious surfaces. Types of wet
weather pollution include CSO, SSO and storm water runoff.
an area that periodically has water logged soils or is covered with a
shallow layer of water resulting in reduced soil conditions. A wetland
area typically supports plant life adapted to wet environments.
mitigation: a regulatory term that refers to the process of constructing
new wetland acreage to compensate for the loss of natural wetlands during
the development process. Mitigation seeks to replace structural and functional
qualities of the natural wetland type that has been destroyed. Storm water
wetlands typically do not count for credit as mitigation, because their
construction does not replicate all the ecosystem functions of a natural
mulch: a technique for establishing low or high marsh areas where
the top 12 inches of wetland soil from a donor wetland are spread thinly
over the surface of a created wetland site as a mulch. The seedbank and
organic matter of the mulch helps to rapidly establish a diverse wetland
perimeter: the wetted surface of a stream (culvert) cross section
which causes resistance to flow. The water to surface interface is a distance,
usually expressed in feet.
a landscape designed with drought-tolerant plants.
an exercise of the police power in which utilization and development of
privately owned land is regulated through the division of a community
into various districts and the specification of permitted and/or prohibited
uses for each district.
variance: a waiver from compliance with a specific provision of the
zoning ordinance granted to a particular property owner because of the
practical difficulties or unnecessary hardship that would be imposed upon
him by the strict application of that provision of the ordinance. The
granting of variances traditionally is the responsibility of the zoning
board of appeals.