Man made Surface water drainage settling lagoon Literature review

Man made Surface water drainage settling lagoon - Literature review Example On the other hand, artificial, sustainable drainage systems (SUDS) for the collection and temporary storage of surface runoff, are constructed for the purpose of attenuation or reduction of released water flow volume as well as water purification. These include Basins, Ponds and alternative forms of attenuation. Thus, Basins are of two types: detention basins and extended detention basins. Ponds are of five types: lagoons, balancing or attenuating ponds, flood storage reservoirs, retention ponds and wetlands. Alternative Forms of Attenuation include the use of over-sized pipes as in rainwater harvesting, tanks, and green roofs. Combined infiltration/ attenuation systems consist of swales and filter strips (SUDS, 2011). Thesis Statement: The purpose of this paper is to investigate the different types of lagoons. The naturally formed coastal lagoons will be examined, followed by a study of the artificial surface water drainage settling lagoon, and the various types of surface run-off storage water bodies, legislation, their management, purpose and concept. Coastal Lagoons are Natural Formations Coastal lagoons are found on all continents, particularly in the low latitudinal zone. They occupy 13 percent of the world’s coastline. These lagoons â€Å"occupy shallow coastal depressions and are separated from the ocean by a barrier† (Kjerfve, 1986 p.63). They are at risk of being completely infilled by sediments, or separated from the sea by littoral drift. In the British Isles there are comparatively few examples of this type of habitat. The coastal lagoon’s physical characteristics and differences are predominantly based on the nature of the channel connecting the lagoon to the adjacent coastal ocean; they are classified as choked, restricted, and leaky systems. Choked lagoons have a single entrance channel which is proportionately smaller in cross-sectional area as compared to the surface area of the lagoon; they are commonly found in coastlines with medium to high wave energy. On the other hand, leaky lagoons have several entrance channels, and have a n aturally large ratio of entrance channel cross-sectional area in relation to the surface area of the lagoon. They are strongly influenced by the ocean’s salinity and tidal variability, and have an occasional significant wave energy. Restricted lagoons form the middle of the spectrum, between the choked and leaky extremes (Kjerfve, 1986). Coastal lagoons are similar to and also different from Manmade surface runoff water collection and storage systems such as ponds, basins and lagoons. Coastal lagoons are characterised by their salt water, and by being impacted by features such as the sea’s tides, the extent of build up of the reefs separating the lagoon from the adjacent sea, and other factors relating to oceanic conditions. These conditions do not affect manmade lagoons. However, natural coastal lagoons as well as manmade lagoons are similarly influenced by rainfall. At the same time, they differ in the surface runoff water that drains into them. Coastal lagoons are m ostly polluted by the soil and other natural debris. On the other hand, the surface runoff that enters ponds, lagoons and basins frequently contains waste materials and sewage from industry, agriculture or other human activities besides soil impurities and natural deposits. Artificial Surface Runoff and Waste Water Drainage Settling Lagoons Ponds constructed for