UNIVERSITY OF LIVINGSTONIA LAWS CAMPUS FACULTY OF APPLIED SCIENCES DEPARTMENT OF ENVIRONMENTAL MANAGEMENT FROM EDDH. P. BANDA REGISTRATION NUMBER ENV/ 01/17/18 TO MR. G. KALENGA COURSE TITLE ENVIRONMENTAL ISSUES COURSE CODE EVM 2301 ASSIGNMENT NUMBER 2 TASK DEFORESTATION IS ONE OF THE ENVIRONMENTAL ISSUES AFFECTING MALAWI. WHAT IS THE ROLE OF VEGETATION IN WATER CONSERVATION? DUE DATE 12TH AUGUST, 2021. Water conservation is the careful use and preservation of water supply. It includes both the quantity and quality of water utilized (Hoekstra & Hannam, 2017). Water is an essential asset for the nourishment of all life and there is a need for it to be conserved. Therefore, water conservation is an important aspect of worksite environmental management. While the environmental concerns with industrial operations often focus on pollution, the intense use of resources, including water, also needs to be taken into consideration. One of the goals of water conservation efforts includes: ensuring the availability of water for future generations where the withdrawal of freshwater from an ecosystem does not exceed its natural replacement rate. Vegetation is one of the measures that helps to conserve water and plays an important role in protecting water quality, and the destruction of vegetation is primarily caused by deforestation. Deforestation not only occurs as a result of firewood extraction by the local population but also as a result of the creation of arable as well as pastoral land (Aubertin, 2011). According to Berger (2004) argues that vegetation helps to slow water movement, reducing soil erosion, which leads to less pollutants getting into our waterways. The trees and ground vegetation in forest ecosystems slow water movement and help stabilize soil. Thus prevention or reduction of soil erosion helps reduce sedimentation type pollution in streams, rivers and lakes. This valuable assistance is provided in several ways. Raindrops hitting leaves, stems and other plant parts get interrupted and redistributed, thereby reducing the velocity of direct soil impact. When the water movement across the soil surface has been reduced, it allows more of the water to soak in. Not only that but also, plant roots help to hold or lock the ground in place (Aubertin, 2011). So Stripping land of vegetation will expose soil and greatly increase the opportunity for soil erosion and stream sedimentation. The steeper the slope of the ground or the more susceptible the soil is to erosion, the greater potential there is for damage. Finer particle clay soil is most easily eroded when bare ground is exposed by these disturbances (Hoekstra & Hannam, 2017). Furthermore, the vegetation along the river is essential for preserving the balance of processes such as sedimentation. Sedimentation is a natural process, but when disturbed, might generate serious problems for the river’s health. High sediment inputs reduce water quality, as the water becomes increasingly turbid. It can also negatively impact water quantity, as sedimentation of river beds decreases the flow capacity of rivers. So riparian vegetation limits the runoff velocity, in turn limiting the amount of sediments that ends up in the river (Patzold & Brummer, 2007). Another way in which vegetation help in water conservation is through infiltration and retention. Trees increase the water infiltration in the soil, increasing groundwater recharge and water retention for longer periods of time. These two processes maintain water available in the soil, which is necessary for microorganisms, other plants and animals. Water infiltration and retention are therefore of great importance for the ecosystem, as well as for the maintenance of local agriculture and livestock rearing (Berger, 2004). For instance, root systems help water penetrate deeper into the soil at a faster rate under and around trees. This means less surface run-off and more water storage in the soil. In rural areas, the removal of trees and hedges and changes in cropping have increased run-off from fields, so planting trees and hedges can be effective in increasing water infiltration, and reducing and slowing run-off on farmland (Hoekstra & Hannam, 2017). In towns and cities, the rise in impermeable surfaces such as roads, pavements and driveways has led to increased surface water run-off. Following UK-wide flooding in the summer of 2007, a report from Sir Michael Pitt identified the paving over of front and rear gardens as a major factor in surface water movement in towns and cities. Around two thirds of all the flooding in 2007 was as a result of surface water run-off (Aubertin, 2011). According to Cardinali (2013) says that vegetation buffer zones around lakes and streams act as a filtering system, reducing the amount of sediments, agricultural chemicals and pesticides in the watercourses. Therefore, the loss of this filtering system results in high levels of sediment and dissolved minerals in rivers and streams which reduce crop growth and disrupt fisheries. Additionally, Riparian vegetation helps to maintain and improve water quality by functioning as a buffer, filtering out sediments and debris. It provides habitats for organisms that contribute to the water's health, and it creates an obstacle that slows down stream flow, especially after a rain event. On the other hand, when the vegetation has been cleared, the land becomes increasingly degraded through misuse, and water supplies suffer. In an environment with vegetative cover, the soil acts like a gigantic sponge, storing a vast quantity of water that is used by plants and trees or released gently into streams and rivers. Therefore, degradation or the removal of vegetation limits the storage capacity of this sponge, leading to water shortages during dry seasons and, in wet seasons, and this may lead to a brief destructive floods, during which very little water is absorbed by the soil. This is why large areas of formerly productive land, where annual rainfall is relatively high, have become decertified once tree cover is removed (Aubertin, 2011). vegetation is also helpful in water conservation through the processes of evaporation and transpiration, where trees release water into the atmosphere. At a later stage in the water cycle, the water masses condensate as rain. Some of this rain will fall in the river catchment and some of it will fall in other regions (Hoekstra & Hannam, 2017). This contribution of vegetation in the water cycle is of great importance for human populations, especially considering the water scarcity that many cities have suffered such as in Brazil where many cities have suffered in last years (Cardinali, 2013). Additionally, growth of vegetation helps covering the ground which can prevent the excess evaporation of water from the soil. Moreover, plants are partially responsible for causing rainfall which increases the ground water level. Vegetation capture and store water and can play an important role in providing drinking water for millions of people in the world's mega-cities. Not only that but vegetation has also contributed to the reduction of water-related risks such as landslides, local floods and droughts and help prevent desertification and salinization (Patzold & Brummer, 2007). In conclusion, the vegetation present in water resources provides greater resistance to water flow. The reduction in the flow of water results in increased infiltration; the trapping of sediments and associated pesticide residues; increased opportunity for assimilation of nutrient run-off by vegetation and microbial populations. Trapping of sediment is an important function, and increased sediment flow into waterways can be harmful to aquatic life due to increased biological demand, and consequently decreased available dissolved oxygen in the waterway. This can promote eutrophication of water bodies due to increased nutrient availability. By supporting the ecosystem through refforestation we keep the water flowing for many people. REFERENCES Aubertin, G.M. (2011). Nature and Extent of Macropores in Forest Soils and their Influence on Subsurface Water Movement. U. K: Department of Agriculture. Berger; P. (2004). Water resources: agricultural and environmental issues. New York: McGrawHall. Cardinali, A. (2013). Herbicides runoff in vegetative filter strips: Evaluation and validation of a recent rainfall returns period model. 3rd edition. California: Elsevier Academic Press. Hoekstra, P.F., & Hannam, C. (2017). Trees and Water Conservation. Uganda: Nkumba University. Patzold, S. C., & Brummer, C.G. (2007). Run-off Reduction during natural and simulated rainfall: Its reduction by vegetated filter strips. U.S.A: Natural Resources Law Center Publications.
