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Variable retention harvesting retains more than 15% of the original stand in both rolling and permanent pockets of untouched trees and refugia patches. Retained forest structure is composed of live and dead trees that enhance structural diversity, and provide a hospitable habitat for variety of living organisms that prevail in the unlogged forest.
Facultative lagoon (polishing pond) providing tertiary treatment after a constructed wetland in Hamburg-Allermöhe, Germany. Overflow from the facultative lagoon may be routed through one or more polishing ponds supporting lower populations of anaerobic micro-organisms and a higher proportion of aerobic organisms adapted to survival in lower concentrations of organic material.
In laboratory experiments, bioretention cells removed 94%, 88%, 95%, and >95% of zinc, copper, lead, and cadmium, respectively from water with metal concentrations typical of stormwater runoff. While this is a great benefit for water quality improvement, bioretention systems have a finite capacity for heavy metal removal.
The first rain gardens were created to mimic the natural water retention areas that developed before urbanization occurred. The rain gardens for residential use were developed in 1990 in Prince George's County, Maryland, when Dick Brinker, a developer building a new housing subdivision had the idea to replace the traditional best management practices (BMP) pond with a bioretention area.
Trees can live for a long time but eventually die, either from natural causes or killed by man. Ill-health of trees can be diagnosed, and early treatment, pruning or felling to prevent the spread may result in timber stocks and amenity trees being saved.
Stormwater management, as a specialized area within the field of environmental engineering, emerged later in the 20th century, and some practitioners have used the term BMP to describe both structural or engineered control devices and systems (e.g. retention ponds) to treat polluted stormwater, as well as operational or procedural practices (e ...
A new Environmental Working Group study says there are contaminants in drinking water that could increase the risk of cancer.
The system may consist of a single pond or several ponds in a series, each pond playing a different role in the removal of pollutants. After treatment, the effluent may be returned to surface water or reused as irrigation water (or reclaimed water) if the effluent meets the required effluent standards (e.g. sufficiently low levels of pathogens).