City Mayors reports news from towns and cities around the world.
Relationship between impervious surfaces and surface runoff Urban runoff is a major cause of urban floodingthe inundation of land or property in a built-up environment caused by rainfall overwhelming the capacity of drainage systemssuch as storm sewers.
Where properties are built with basementsurban flooding is the primary cause of basement flooding. Flood flows in urban environments have been investigated relatively recently despite many centuries of flood events. Several studies looked into the flow patterns and redistribution in streets during storm events and the implication in terms of flood modelling.
Roads and parking lots are major sources of polycyclic aromatic hydrocarbons PAHswhich Urban pollution created as combustion byproducts of gasoline and other fossil fuelsas well as of the heavy metals nickelcopperzinccadmiumand lead. Roof runoff contributes high levels of synthetic organic compounds and zinc from galvanized gutters.
Fertilizer use on residential lawns, parks and golf courses is a measurable source of nitrates and phosphorus in urban runoff when fertilizer is improperly applied or when turf is over-fertilized.
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. Limited native vegetation and excessive algae has the potential to disrupt the entire aquatic ecosystem due to limited light penetration, lower oxygen levels, and reduced food reserves.
Excessive levels of sediment and suspended solids have the potential to damage existing infrastructure as well. Sedimentation can increase runoff by plugging underground injection systems, thereby increasing the amount of runoff on the surface.
Increased sedimentation levels can also reduce storage behind reservoirs. This reduction of reservoir capacities can lead to increased expenses for public land agencies while also impacting the quality of water recreational areas.
Small amounts of heavy metals are carried by runoff into the oceans. These metals are ingested by ocean life. These heavy metals cannot be disposed so they accumulate within the animals. Over time, these metals build up to a toxic level, and the animal dies.
This heavy metal poisoning can also affect humans. If we eat a poisoned animal, we have a chance of getting heavy metal poisoning too. In fact, the impervious cover in a typical city creates five times the runoff of a typical woodland of the same size.Transportation-related air pollution, which is a significant contributor to total urban air pollution, increases the risks of cardiopulmonary-related deaths and non-allergic.
Light pollution—what is it and why is it important to know? Light pollution is excessive and inappropriate artificial light.
The four components of light pollution are often combined and may overlap. IntroductionAir pollution is a major environmental concern in most major cities across the world.
An important focus of research has been on the role of urban vegetation in the formation and degradation of air pollutants in cities. New research shows that noise pollution in US cities is concentrated in poor and minority communities. Beyond regulating airplane noise, the US has done relatively little to curb noise pollution.
Urban runoff is surface runoff of rainwater created by vetconnexx.com runoff is a major source of flooding and water pollution in urban communities worldwide.. Impervious surfaces (roads, parking lots and sidewalks) are constructed during land vetconnexx.com rain storms and other precipitation events, these surfaces (built from materials such as asphalt and concrete), along with.
An initiative led by the Wilson Center in partnership with the General Services Administration (GSA).