![Storm Drain](https://upload.wikimedia.org/wikipedia/commons/5/5c/Storm_drain.jpg)
Urban runoff is
surface runoff
Surface runoff (also known as overland flow) is the flow of water occurring on the ground surface when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when th ...
of rainwater, landscape irrigation, and car washing created by
urbanization
Urbanization (or urbanisation) refers to the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It is predominantly t ...
.
Impervious surfaces
Impervious surfaces are mainly artificial structures—such as pavements (roads, sidewalks, driveways and parking lots, as well as industrial areas such as airports, ports and logistics and distribution centres, all of which use considerable pav ...
(
road
A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation.
There are many types of ...
s,
parking lot
A parking lot (American English) or car park (British English), also known as a car lot, is a cleared area intended for parking vehicles. The term usually refers to an area dedicated only for parking, with a durable or semi-durable surface ...
s and
sidewalk
A sidewalk (North American English), pavement (British English), footpath in Australia, India, New Zealand and Ireland, or footway, is a path along the side of a street, street, highway, terminals. Usually constructed of concrete, pavers, brick ...
s) are constructed during
land development
Land development is the alteration of landscape in any number of ways such as:
* Changing landforms from a natural or semi-natural state for a purpose such as agriculture or housing
* Subdividing real estate into lots, typically for the purpose ...
. During
rain
Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...
, storms and other
precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...
events, these surfaces (built from materials such as
asphalt
Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term a ...
and
concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...
), along with
roof
A roof ( : roofs or rooves) is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of temper ...
tops, carry polluted
stormwater
Stormwater, also spelled storm water, is water that originates from precipitation (storm), including heavy rain and meltwater from hail and snow. Stormwater can soak into the soil ( infiltrate) and become groundwater, be stored on depressed la ...
to
storm drains, instead of allowing the water to
percolate through
soil
Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...
.
This causes lowering of the
water table
The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated.
T ...
(because
groundwater recharge
Groundwater recharge or deep drainage or deep percolation is a hydrologic process, where water moves downward from surface water to groundwater. Recharge is the primary method through which water enters an aquifer. This process usually occurs in ...
is lessened) and
flood
A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...
ing since the amount of water that remains on the surface is greater.
[Water Environment Federation](_blank)
Alexandria, VA; an
American Society of Civil Engineers
Reston, VA
"Urban Runoff Quality Management."
WEF Manual of Practice No. 23; ASCE Manual and Report on Engineering Practice No. 87. 1998. . Chapter 1. Most municipal storm sewer systems discharge stormwater, untreated, to
stream
A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...
s,
river
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...
s and
bays. This excess water can also make its way into people's properties through basement backups and seepage through building wall and floors.
Urban runoff can be a major source of
urban flooding
Urban flooding is the inundation of land or property in a built environment, particularly in more densely populated areas, caused by rainfall overwhelming the capacity of drainage systems, such as storm sewers. Although sometimes triggered by even ...
and
water pollution
Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water ...
in urban communities worldwide.
Pollutants
Water running off
impervious surfaces
Impervious surfaces are mainly artificial structures—such as pavements (roads, sidewalks, driveways and parking lots, as well as industrial areas such as airports, ports and logistics and distribution centres, all of which use considerable pav ...
in urban areas tends to pick up
gasoline
Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic co ...
,
motor oil
Motor oil, engine oil, or engine lubricant is any one of various substances used for the lubrication of internal combustion engines. They typically consist of base oils enhanced with various additives, particularly antiwear additives, deterg ...
,
heavy metals
upright=1.2, Crystals of osmium, a heavy metal nearly twice as dense as lead">lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead
Heavy metals are generally defined as ...
,
trash
Trash may refer to:
Garbage
* Garbage, unwanted or undesired waste material
** Litter, material discarded in inappropriate places
** Municipal solid waste, unwanted or undesired waste material generated in a municipal environment
Arts, enter ...
and other pollutants from roadways and parking lots, as well as
fertilizers
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
and
pesticides
Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampric ...
from lawns. Roads and parking lots are major sources of
polycyclic aromatic hydrocarbon
A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. ...
s (PAHs), which are created as the byproducts of the
combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combusti ...
of gasoline and other
fossil fuel
A fossil fuel is a hydrocarbon-containing material formed naturally in the Earth's crust from the remains of dead plants and animals that is extracted and burned as a fuel. The main fossil fuels are coal, oil, and natural gas. Fossil fuels m ...
s, as well as of the heavy metals
nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...
,
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
,
zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
,
cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...
, and
lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
. Roof runoff contributes high levels of
synthetic organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
s and
zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
(from
galvanized
Galvanization or galvanizing ( also spelled galvanisation or galvanising) is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which the parts are submerged ...
gutters). Fertilizer use on residential lawns, parks and golf courses is a measurable source of
nitrates
Nitrate is a polyatomic ion with the chemical formula . Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are soluble in water. An example of an insoluble ...
and
phosphorus
Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
in urban runoff when fertilizer is improperly applied or when turf is over-fertilized.
Eroding soils or poorly maintained construction sites can often lead to increased
sedimentation
Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...
in runoff. Sedimentation often settles to the bottom of water bodies and can directly affect water quality. Excessive levels of sediment in water bodies can increase the risk of infection and disease through high levels of nutrients present in the soil. These high levels of nutrients can reduce oxygen and boost algae growth while limiting native vegetation growth, which can disrupt
aquatic ecosystem
An aquatic ecosystem is an ecosystem formed by surrounding a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms that are dependent on each other and on their environment. The tw ...
Excessive levels of sediment and
suspended solids
Suspended solids refers to small solid particles which remain in suspension in water as a colloid or due to motion of the water. Suspended solids can be removed by sedimentation if their size or density is comparatively large, or by filtration. It ...
have the potential to damage existing infrastructure as well. Sedimentation can increase surface runoff by plugging underground injection systems. Increased sedimentation levels can also reduce storage behind
reservoir
A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation.
Reservoirs can be created in a number of ways, including contro ...
. This reduction of reservoir capacities can lead to increased expenses for public land agencies while also impacting the quality of water recreational areas.
Runoff can also induce
bioaccumulation
Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...
and
biomagnification
Biomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain. This increase can occur as a ...
of toxins in ocean life. Small amounts of heavy metals are carried by runoff into the oceans, which can accumulate within aquatic animals to cause
metal poisoning
Metal toxicity or metal poisoning is the toxic effect of certain metals in certain forms and doses on life. Some metals are toxic when they form poisonous soluble compounds. Certain metals have no biological role, i.e. are not essential minerals, ...
. This heavy metal poisoning can also affect humans, since ingesting a poisoned animal increases the risk of heavy metal poisoning.
As stormwater is channeled into storm drains and surface waters, the natural
sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...
load discharged to receiving waters decreases, but the water flow and velocity increases. In fact, the impervious cover in a typical city creates five times the runoff of a typical woodland of the same size.
Effects
Dry weather discharges
Overwatering through
irrigation by sprinkler may produce runoff reaching receiving waters during
low flow conditions. Runoff carries accumulated pollutants to streams with unusually low dilution ratios causing higher pollutant concentrations than would be found during regional precipitation events.
Urban flooding
![Natural & impervious cover diagrams EPA](https://upload.wikimedia.org/wikipedia/commons/4/46/Natural_%26_impervious_cover_diagrams_EPA.jpg)
Urban runoff is a major cause of
urban flooding
Urban flooding is the inundation of land or property in a built environment, particularly in more densely populated areas, caused by rainfall overwhelming the capacity of drainage systems, such as storm sewers. Although sometimes triggered by even ...
, the inundation of land or property in a built-up environment caused by rainfall overwhelming the capacity of
drainage systems, such as
storm sewers.
Triggered by events such as
flash flooding
A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice or snow flowing o ...
,
storm surges, overbank flooding, or
snow melts, urban flooding is characterized by its repetitive, costly and systemic impacts on communities, even when not within
floodplains
A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...
or near any body of water.
There are several ways in which stormwater enters
properties
Property is the ownership of land, resources, improvements or other tangible objects, or intellectual property.
Property may also refer to:
Mathematics
* Property (mathematics)
Philosophy and science
* Property (philosophy), in philosophy and ...
: backup through sewer pipes, toilets and sinks into buildings; seepage through building walls and floors; the accumulation of water on the property and in public rights-of-way; and the overflow of water from water bodies such as rivers and lakes. Where properties are built with basements, urban flooding is the primary cause of basement flooding.
Water pollution
Urban runoff contributes to
water quality
Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...
problems. In 2009 the US
National Research Council National Research Council may refer to:
* National Research Council (Canada), sponsoring research and development
* National Research Council (Italy), scientific and technological research, Rome
* National Research Council (United States), part of ...
published a comprehensive report on the effects of urban stormwater and stated that it continues to be a major contamination source in many watersheds throughout the United States.
The report explained that "...further declines in water quality remain likely if the land-use changes that typify more diffuse sources of pollution are not addressed... These include land-disturbing agricultural, silvicultural, urban, industrial, and construction activities from which hard-to-monitor pollutants emerge during wet-weather events. Pollution from these landscapes has been almost universally acknowledged as the most pressing challenge to the restoration of waterbodies and aquatic ecosystems nationwide."
![Mali, Bamako, Rue 249 (1)](https://upload.wikimedia.org/wikipedia/commons/7/76/Mali%2C_Bamako%2C_Rue_249_%281%29.JPG)
The runoff also increases temperatures in streams, harming
fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
and other organisms. (A sudden burst of runoff from a rainstorm can cause a fish-killing shock of hot water.) Also,
road salt
Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g/ ...
used to melt snow on sidewalks and roadways can contaminate streams and groundwater
aquifer
An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...
s.
One of the most pronounced effects of urban runoff is on watercourses that historically contained little or no water during dry weather periods (often called ''
ephemeral streams''). When an area around such a stream is
urbanized
''Urbanized'' is a documentary film directed by Gary Hustwit and released on 26 October 2011. It is considered the third of a three-part series on design known as the Design Trilogy; the first being ''Helvetica'', about the typeface, and the seco ...
, the resultant runoff creates an unnatural year-round
streamflow
Streamflow, or channel runoff, is the flow of water in streams and other channels, and is a major element of the water cycle. It is one component of the movement of water from the land to waterbodies, the other component being surface runoff. Water ...
that hurts the vegetation,
wildlife
Wildlife refers to domestication, undomesticated animal species (biology), species, but has come to include all organisms that grow or live wilderness, wild in an area without being species, introduced by humans. Wildlife was also synonymous ...
and
stream bed
A stream bed or streambed is the bottom of a stream or river (bathymetry) or the physical confine of the normal water flow (Channel (geography), channel). The lateral confines or channel margins are known as the stream Bank (geography), banks ...
of the waterway. Containing little or no sediment relative to the historic ratio of sediment to water, urban runoff rushes down the stream channel, ruining natural features such as
meander
A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex bank ...
s and
sandbar
In oceanography, geomorphology, and Earth science, geoscience, a shoal is a natural submerged ridge, bank (geography), bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body o ...
s, and creates severe erosion—increasing sediment loads at the mouth while severely carving the
stream bed
A stream bed or streambed is the bottom of a stream or river (bathymetry) or the physical confine of the normal water flow (Channel (geography), channel). The lateral confines or channel margins are known as the stream Bank (geography), banks ...
upstream. As an example, on many
Southern California
Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most po ...
beaches at the mouth of a waterway, urban runoff carries trash, pollutants, excessive silt, and other wastes, and can pose moderate to severe health hazards.
Because of fertilizer and organic waste that urban runoff often carries,
eutrophication
Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytopla ...
often occurs in waterways affected by this type of runoff. After heavy rains, organic matter in the waterway is relatively high compared with natural levels, spurring growth of
algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
blooms that soon consume most of the
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
. Once the naturally occurring oxygen in the water is depleted, the algae blooms die, and their decomposition causes further eutrophication. These algae blooms mostly occur in areas with still water, such as
stream pool
A stream pool, in hydrology, is a stretch of a river or stream in which the water depth is above average and the water velocity is below average.
Formation
A stream pool may be bedded with sediment or armoured with gravel, and in some cases th ...
s and the pools behind
dam
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...
s,
weir
A weir or low head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the river level. Weirs are also used to control the flow of water for outlets of l ...
s, and some
drop structure
A drop structure, also known as a grade control, sill, or weir, is a manmade structure, typically small and built on minor streams, or as part of a dam's spillway, to pass water to a lower elevation while controlling the energy and velocity of the ...
s. Eutrophication usually comes with deadly consequences for fish and other aquatic organisms.
![Oil-grit separator USGS 2002](https://upload.wikimedia.org/wikipedia/commons/e/e2/Oil-grit_separator_USGS_2002.png)
Excessive stream bank erosion may cause flooding and property damage. For many years governments have often responded to urban stream erosion problems by modifying the streams through construction of hardened
embankments and similar control structures using concrete and masonry materials. Use of these hard materials destroys habitat for fish and other animals. Such a project may stabilize the immediate area where flood damage occurred, but often it simply shifts the problem to an upstream or downstream segment of the stream. ''See
River engineering
River engineering is a discipline of civil engineering which studies human intervention in the course, characteristics, or flow of a river with the intention of producing some defined benefit. People have intervened in the natural course and b ...
''.
There are many different ways that polluted urban runoff could harm humans, such as by contaminating drinking water, disrupting food sources and even causing parts of beaches to be closed off due to a risk of illness. After heavy rainfall events that cause stormwater overflows, contaminated water can impact waterways in which people recreate or fish, causing the beaches or water-based activities to be closed. This is because the runoff has likely caused a spike in harmful bacterial growth or inorganic chemical pollution in the water. The contaminants that we often think of as the most damaging are gasoline and oil spillage, but we often overlook the impact that fertilizers and insecticides have. When plants are watered and fields irrigated, the chemicals that lawns and crops have been treated with can be washed into the water table. The new environments that these chemicals are introduced to suffer due to their presence as they kill native vegetation, invertebrates, and vertebrates.
Prevention and mitigation
Effective control of urban runoff involves reducing the velocity and flow of stormwater, as well as reducing pollutant discharges. Local governments use a variety of stormwater management techniques to reduce the effects of urban runoff. These techniques, called
best management practices for water pollution (BMPs) in some countries, may focus on water quantity control, while others focus on improving water quality, and some perform both functions.
Pollution prevention practices include
low impact development (LID) or
green infrastructure
Green infrastructure or blue-green infrastructure refers to a network that provides the “ingredients” for solving urban and climatic challenges by building with nature.Hiltrud Pötz & Pierre Bleuze (2011). Urban green-blue grids for sustainab ...
techniques - known as
Sustainable Drainage Systems (SuDS) in the UK, and
Water-Sensitive Urban Design (WSUD) in Australia and the Middle East - such as the installation of
green roof
A green roof or living roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage ...
s and improved chemical handling (e.g. management of motor fuels & oil, fertilizers, pesticides and
roadway deicers).
Runoff mitigation systems include
infiltration basin
An infiltration basin (or recharge basin) is a form of engineered sump or percolation pond that is used to manage stormwater runoff, prevent flooding and downstream erosion, and improve water quality in an adjacent river, stream, lake or bay. It is ...
s,
bioretention
Bioretention is the process in which contaminants and sedimentation are removed from stormwater runoff. The main objective of the bioretention cell is to attenuate peak runoff as well as to remove stormwater runoff pollutants.
Construction of ...
systems,
constructed wetland
A constructed wetland is an artificial wetland to treat sewage, greywater, stormwater runoff or industrial wastewater. It may also be designed for land reclamation after mining, or as a mitigation step for natural areas lost to land development. ...
s,
retention basin
A retention basin, sometimes called a wet pond, wet detention basin, or stormwater management pond (SWMP), is an artificial pond with vegetation around the perimeter and a permanent pool of water in its design. It is used to manage stormwater r ...
s and similar devices.
Providing effective urban runoff solutions often requires proper city programs that take into account the needs and differences of the community. Factors such as a city's mean temperature, precipitation levels, geographical location, and airborne pollutant levels can all affect rates of pollution in urban runoff and present unique challenges for management. Human factors such as urbanization rates, land use trends, and chosen building materials for impervious surfaces often exacerbate these issues.
The implementation of citywide maintenance strategies such as street sweeping programs can also be an effective method in improving the quality of urban runoff.
Street sweeping vacuums collect particles of dust and suspended solids often found in public parking lots and roads that often end up in runoff.
Educational programs can also be an effective tool for managing urban runoff. Local businesses and individuals can have an integral role in reducing pollution in urban runoff simply through their practices, but often are unaware of regulations. Creating a productive discussion on urban runoff and the importance of effective disposal of household items can help to encourage environmentally friendly practices at a reduced cost to the city and local economy.
[
]
Thermal pollution from runoff can be controlled by stormwater management facilities that absorb the runoff or direct it into
groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidate ...
, such as bioretention systems and infiltration basins. Bioretention basins tend to be less effective at reducing temperature, as the water may be heated by the sun before being discharged to a receiving stream.
Stormwater harvesting Stormwater harvesting or Stormwater reuse is the collection, accumulation, treatment or purification, and storage of stormwater for its eventual reuse. While rainwater harvesting collects precipitation primarily from rooftops, stormwater harvesting ...
deals with the collection of runoff from creeks, gullies, ephemeral streams, and other ground conveyances. Stormwater harvesting projects often have multiple objectives, such as reducing contaminated runoff to sensitive waters, promoting groundwater recharge, and non-potable applications such as
toilet flushing
A flush toilet (also known as a flushing toilet, water closet (WC) – see also toilet names) is a toilet that disposes of human waste (principally urine and feces) by using the force of water to ''flush'' it through a drainpipe to another loca ...
and
irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...
.
See also
*
Agricultural wastewater treatment - Nutrient runoff
*
First flush
First flush is the initial surface runoff of a rainstorm. During this phase, water pollution entering storm drains in areas with high proportions of impervious surfaces is typically more concentrated compared to the remainder of the storm. Conse ...
(initial runoff of a rainstorm)
*
List of environmental issues
This is an alphabetical list of environmental issues, harmful aspects of human activity on the biophysical environment. They are loosely divided into causes, effects and mitigation, noting that effects are interconnected and can cause new effects. ...
*
Nationwide Urban Runoff Program, a research project conducted by the US Environmental Protection Agency
*
Nonpoint source pollution
Nonpoint source (NPS) pollution refers to diffuse contamination (or pollution) of water or air that does not originate from a single discrete source. This type of pollution is often the cumulative effect of small amounts of contaminants gathered ...
*
Rainwater harvesting
Rainwater harvesting (RWH) is the collection and storage of rain, rather than allowing it to run off. Rainwater is collected from a roof-like surface and redirected to a tank, cistern, deep pit (well, shaft, or borehole), aquifer, or a reservoir w ...
*
Surface runoff - Agricultural issues
References
Further reading
*
*
* Anstett, Catherine. “SALMON AND PIPER'S CREEK WATERSHED.” Carkeek Watershed Community Action Project, 2015,
http://www.carkeekwatershed.org/wp-content/uploads/Salmon-Guide-Fall-2015.pdf. Accessed 9 December 2021.
*
* “Component: Swales.” Susdrain,
https://www.susdrain.org/delivering-suds/using-suds/suds-components/swales-and-conveyance-channels/swales.html. Accessed 9 December 2021.
*
* “Get Rid of Motor Oil Stains.” Parkside Motors,
https://parksidemotors.ca/remove-oil-stains-from-surfaces/. Accessed 9 December 2021.
*
* National Ocean Service. "MBNMS: What You Can Do To Reduce Urban Runoff Pollution." Monterey Bay National Marine Sanctuary, National Ocean Service, 9 December 2019,
https://montereybay.noaa.gov/resourcepro/urbancando.html. Accessed 9 December 2021.
*
* Rosen, Julia. “Road Runoff a No-No for Coho.” Scientific American, 26 October 2015,
https://www.scientificamerican.com/podcast/episode/road-runoff-a-no-no-for-coho/. Accessed 9 December 2021.
* “Runoff: Surface and Overland Water Runoff.” Water Science School, USGS, 6 June 2018,
https://www.usgs.gov/special-topics/water-science-school/science/runoff-surface-and-overland-water-runoff .
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{{Authority control
Environmental issues with water
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Water pollution