Flood control in river basins has become more important in recent Essay

Flood control in river basins has become more important in recent years. Discuss various techniques used for flood control and t - Essay Example The flood defenses were strong barriers that prevented water from flooding into the plain land (Woods & Woods 2007, p.5). Floods occur when flowing surface water spills over the confining banks into the dry land. Floods are a natural phenomenon, which occur in almost all river systems. Areas prone to flooding include those located downstream of dams and the low lying regions. Flooding causes immense losses, which include loss of human and animal life, soil erosion, damage on properties, destruction of vegetation and many environmental damages. In addition, areas affected by floods are highly susceptible to famines and prolonged droughts. This further causes loss of human and animal life due to starvation. Floodwaters are usually contaminated with harmful microorganisms derived from raw sewage. This puts people affected by the floods at greater risks of getting infectious diseases (Proverbs, et al., 2011, p. 221). Floods may contribute to some positive impacts on the ecosystem. One of the benefits of flooding includes offering fresh water for domestic use and irrigation. The other benefit includes massive deposition of minerals and nutrients into the affected areas. Apart from these benefits, floods also help in improving the condition of aquatic ecosystems. However, they can be regarded as the most damaging compared to volcanic eruptions and earthquakes. Therefore, stringent measures must be undertaken to prevent the massive losses incurred during floods. This paper discusses various techniques used in controlling floods and their environmental impacts (Gruntfest & Handmer, 2001, p.12). Methods used to control floods Techniques applied in controlling floods entail the modification of the river environment and areas located close to the river. Flood control techniques can be applied on the river channel, floodway or on the floodplain (Ghosh, 1997, p.55). Techniques applied in floodplains Floodplains are those regions that lie below the flood elevation and exclus ively on the floodway and river channel. Majority of techniques applied on the floodplains lie far from the river, but are designed to reduce damage from floods. Levee around structures This technique entails the construction of a levee/floodwall around structures located in floodplains. Levees can either be permanent or temporally. Construction of the levee requires the use of strong, natural or artificial material that can withstand pressure from the floods (Hyndman & Hyndman, 2010, p.356). The essence of using levees and other barriers is to raise the height in structures located in floodplains which floodwater must rise to in order cause flooding. These structures offer protection to structures but put other structures into a high risk of flooding due to increased water retention in the floodplains. In addition, serious damage to protected structures can arise when the levees are unable to hold back the floods. This is because the pressure at which the floods hit the structure i s extremely high compared to when there is no barrier (Green, 2004, p.36). The use of levees, floodwalls, and dykes has a negative impact on natural river processes (Harmancioglu, 1994, p.42). Ideally, water spills emerging from a river should form a natural channel which provides a way for the floods to flow. Therefore, levees reduce the ability of the floodplains to process floodwaters. In addition, the