Effects of Land Degradation in the Murray-Darling Basin - Research Paper Example

Effects of Land Degradation in the Murray-Darling Basin Australia is the driest continent on the planet. The area is characterized by low rainfall amounts while a significant part of its land is either arid or semi-arid land. For many years, the country has been known to experience long drought spells where water shortages are usually experienced. The rain deficiency witnessed in Australia annually affects the water and drainage basins as these results in small areas of permanent wet lands, decreased river water, and lowest run off. One of the drainage basins that has attracted attention is the Murray-darling Basin that is the largest fresh water supplier to the South Eastern parts of Australia. Geographically, the Murray-Darling Basin covers a large area that also captures the Darling River, the Murray River, and the Murrumbridge River. This makes up for 14% of the nation’s total area (Hawke n.p). In essence, this drainage area is very important as it helps propel the Australian economy and supports the activities of the rural communities. However, the increased land degradation in the area has had a negative impact on the basin’s capabilities, which may greatly affect the social and economic situation of the country if it remains unchecked. The basin covers several Australian states that include Queensland, South Australia, New South Wales, Victoria, and Australian Capital Territory. The agricultural sector of Australia greatly depends on this water basin for irrigation where 85% of the water goes into this industry(Hawke n.p). Over the last few years, the productivity of the water drainage body has gradually shrunk due to human activities and droughts that have degraded the basin’s land hence making it to be a matter of concern.Land degradation refers to any changes to land that result in its reduced quality or condition, which reduces its productivity. Human activities are the strongest contributors to the increasing land degradation rates, which is an indication of the spreading desertification across Australia. Mostly land degradation results from over utilization of land and its resources. It occurs through desertification, soil erosion, salinization,loss of biodiversity, and reduction in ground water quality and quantity. The prevailing climatic conditions are also contributing to Murray-Darling basin reducing in size with each passing day. Desertification Desertification is a form of land degradation that mostly affects dry land ecosystems because of both natural and human activities (Dregne n.p). Desertification can be a cumulative effect of deforestation, poor irrigation, overgrazing, droughts, and over-cultivation that can lead to land degradation. Grasslands, savannas, and woodlands are the common indicators to the start of desertification in both arid and semi arid areas. Better-placed examples of these are Taklamakhan Desert in China, the Adriatic Sea in Europe and the Sahara desert. One of the major causes of soil erosion is deforestation,as this aspect tends to weaken the soil to an extent that it cannot retain any water. Evaporation easily occurs when the soil is weak and soil erosion is usually rampant in areas near water bodies. Drought is another type of water evaporation, which is relatively a length in time when an area previously experienced rain. In areas where there is soil erosion and drought end to experience high rates of evaporation, making the areas slowly to turn into deserts. When water bodies begin to dry up, then this also becomes a sure sign that the region would eventually turn into a desert. In the end, these regions end up being unstable and can no longer sustain vegetation, human life, and wildlife hence displacing the population due to the land to become less suitable for cultivation (Dregne n.p). The increased size of land in the basin affected by desertification and land degradation has attracted the interest of environmentalists, as these issues are preventable and at times reversible. The concern is however on the land that is left degraded when those that finds it to no longer be productive because this trend can be a worrying one. In essence, the degraded lands should be worked on so as to reverse the effects of natural and human activities and make the lands productive again. The leading cause of desertification in the basin is overgrazing by domesticated animals and their naturally occurring counterparts. Australia is renowned for its cattle producing abilities. These animals have to eat in an environment where water and natural vegetation are scarce. The downside to this is that the animals overgraze on the already little vegetation, which leaves the land bare. At the same time, the over utilization of the basin’s water also occurs. The Murray-Darling river system is one of the largest in the world with human manipulation resulting in the regulation of the water flow. Being the food basket region for Australia, a large part of the basin is put under irrigation using the controlled waters (Discover Murray n.p). The result is that there is less water for the downstream areas which onsets desertification as there is less water for systems like the Barmah-Millewa forest that require plenty of water for survival. The effects of the desertification of the basin manifests in a number of ways. First, the condition has resulted in the reduction for precipitation received in the region. In the period between 2001 and 2009, the area experienced its worst drought on record during which it received below than average amounts of precipitation. Reduced precipitation means that there is less surface water available for various uses. It also means that there is less surface runoffs and lowered ground water tables. The result is the salinization of the topsoil and groundwater. In the event that this area receives precipitation, the salt in the topsoil is carried by the surface run off which increases salinity of the river. The loss of vegetation also exposes the land to a number of things. Vegetation is responsible for the interception of rain before it hits the ground. It also produces humus that is largely responsible for increased water retention capacities of soil. Tree roots make crevices in the ground that help in the percolation and infiltration of precipitation. Trees also hold the soli together and aid in providing resistance to surface run offs. At the same time, through the processes of evapotranspiration, they are able to return water from precipitation to the atmosphere and prevent its loss through run offs. This means that the desertification that results in the loss of vegetation also reduces the water retention capacities of the land that results in further degradation. Soil erosion Soil erosion is a method of land degradation that involves the removal of the top soil of an area through agents of nature like wind and water. The clearing of vegetation for cultivation, overgrazing, and desertification results in the exposure of the soil to these agents.Wind erosion is a particularly major problem in the drier regions of the basin (Murray-Darling Basin Authority n.p). It mainly involves the loss of the finer particles of the soil. In the drier areas, the top soil is mainly sandy. Cultivation and stock movement further breaks down the already loose soil particles into sizes that are more easily moved by the wind. Fine soil areas have the risk of wind erosion increased by cultivation, overgrazing, and exposure of the cropland. Water erosion refers to the removal of soil from the land by rain or river water. In this type of erosion, large volumes of soil are washed away downstream. Erosion negatively affects the quality of the land by reducing the fertility of the soil. Most of the soils in Australia and therefore in the basin are shallow. This means that the bulk of nutrients that make them fertile are found in the top few centimeters. When erosion occurs these top centimeters are carried away, which damages the land heavily. The remaining soils tend to be unproductive as they lack in nutrients. This means that the area often remains uncolonised by the native vegetation. As such, it remains susceptible to more erosion by the agents. The effect is that the next erosion takes place with an even larger magnitude. If there is increased precipitation, gully erosion may occur with the land being deformed. This phenomenon is the reason why there are so many gullies in the drier parts of the basin. In the end, the erosion result in the creation of scalded pieces of land (Murray-Darling Basin Authority n.p). Scalds are the unproductive and bare land pieces where erosion has removed the topsoil leaving unfertile soils. Scalds can cover large areas. In the basin, there have been areas in the past affected by this phenomenon with the Riverine plain being a prime example. However, the effect of erosion has to do with more than just removal of nutrients from soils. This is because with wind erosion, the soil is carried over large distances on land before being dropped. When this happens to large volumes of soil, it may cause major damage with fences and roads covered, crops ruined after being buried and blocking of culvers and drains. In the case of water erosion, the runoff always ends up in the river systems. This means that it brings large volumes of soils into the rivers. This negatively affects the water sources in two ways. The first and most obvious way is that the quality of water in the river system degrades. The addition of large volumes of dirt to river waters will mean the need to do more to make the water safe for domestic consumption. The second effect is the siltation of the river systems. This means that the water reservoirs along the system will store smaller amounts of water as the silt takes up space. As such, the power production ability reduces. It may also mean the blocking of Murray River mouth like in 1981.This may result in flooding of the areas as well as loss of the important wildlife that live and depend on the estuary. Salinization Salinization is the process where dissolved salts concentrate in soil or water. Its value expression utilizes electrical conductivity (EC) or concentration (mg/L). Due to the increased levels of desertification and reduced precipitation, the Murray Basin has seen increased levels of salinity. The Basin has a flat terrain with high evaporation rates and low rainfall. All three of these are ideal conditions for the accumulation of salts in increased amounts on and below landscape. The salt in the region is naturally occurring (Lawson 69). Its derivation is from the weathering of rocks, ancient oceanic sediments, and rainfall deposition over millions of years. The land degradation in the Murray-Darling basin by salinity is not due to addition of salts but rather the mobilization of pre-existing salts. This phenomenon occurs naturally. However, human activities like land clearing and irrigation development have purposed to accelerate the mobilization of salts in the groundwater, soils, and river water. When the ,we clear originally deep rooted vegetation and replace it with shallow rooted pastures and crops, the groundwater rises resulting in dry land salinity. This is the accumulation of salts in the soil surface (Lawson 69). In some regions of the basin, groundwater flows freely into the rivers. Years of degradation result in the accumulation of salts in both groundwater and the surface. When droughts end and the area receives significant amounts of rainfall, the area experiences recharging of the groundwater. The recharged groundwater that is high in salinity then flows back into the river systems. This results in a negative effect on the aquatic life and vegetation. Salinity levels in rivers increase with the return of base flowlevels, which make the river water less suitable for drinking and irrigation. Since Australia is mainly dry and the southeastern region relies on the piped water from the basin to supply the residents, the increased salinity will result in destruction of the already existing infrastructure as the water corrodes the plumbing. The economic costs also increase, as the water requires further treatment to remove the increased salts from the water (Lawson 69). Utilization of the water in irrigation will also result in a negative effect. As discussed earlier, the Murray-Basin is the largest source of food for the Australian population as it produces around 40% of the total. However, this production relies on the irrigation water from the river systems (Discover Murray n.p). Crops require certain levels of salts in the soil in order to prosper. However, increased salt levels result in wilting of crops as they lose water by osmosis to the soil. As such, the salinization of the soils causes the crops to have lower yields. The yield reduction sees further reduction due to salinization as a result of the utilization of the irrigation water. With the groundwater recharging and rainwater runoffs multiplying the salinity of the water many folds, the irrigation water turns out to have very high salinity levels. Utilization of this water on the crops means that there will be increased salinity levels in the soil and water for absorption by the crops. This means that irrigation will purpose to reduce productivity of the crops instead of boosting it. Algal bloom A large part of the basin is under cultivation. However, with the onset of the degradation processes illustrated in the paper, the fertility of the soils and other factors make it necessary to utilize such inputs like fertilizers to ensure sustainability of the crops. With time, a lot of fertilizer has been utilized to make the soil fertile and grow crops. However, the years of degradation and the clearing of pre-existing deep-rooted vegetation and replacement with shallow rooted crops have greatly reduced the water retention capacities of the land. This means that when the area receives significant rainfall, the fertilizers get washed into the river systems. With the onset of droughts, the water levels in the rivers drop making the rivers calm (Wohl 239). The high nutrients and calm nature of the waters results in blooms of algae. These blooms interfere with the use of water with far reaching effects on human health, the environment, and the economy. The algae create undesirable odors and tastes in the water accompanied by scum and discoloration. Some species produce toxins that may upset the stomach, damage the liver, and create nervous system disorders (Wohl 239). Although there are no reported human deaths from algae, they bloom may result in large stock deaths. The algae may also result in damages to infrastructure and water supply interruptions as they block filters and equipment. Even in death, these microscopic organisms have a negative effect as their decay results in oxygen depletion that produces blackwater, which kills aquatic animals. Socioeconomic impact Land degradation in the basin hinders agricultural practices, which threatens the economy of the region and the nation as a whole. Desertification results in the reduction of precipitation received in the area and the reduction of groundwater levels. It also causes a reduction in the water volumes of the water system and therefore the water available for irrigation. This means that there is less water available for cultivation. At the same time, soil erosion also reduces the water available for cultivation through siltation of reservoirs and reduction of water retention abilities. Soil erosion on the other hand, scalds the land and resorting in unfertile, uncultivatable, and disfigured lands. Salinization of both the land and groundwater resorts in the existence of tracts of unfertile lands that are irrigated with water that is unhealthy for crops (Williams 488). As such, the phenomenon of land degradation hinders the agricultural capabilities of the region. This means that it leads to the production of less food in the food basket region, which threatens the food security of the nation. This potentially means the inflation in cost of food in the nation. The Murray-Basin produces 40% of the nation’s food and hosts a large population. Many of these residents practice agriculture and rely on it for their livelihoods. Since land degradation threatens the region’s ability to produce food, it also threatens the socioeconomic status of the nation, as the farmers are likely to lose their employment. It also creates a situation where the population is prone communicable diseases resulting from inadequate water. Land degradation also negatively affects the quality and quantity of land. Desertification results in the reduction of availability of water. This means that there is less water available in the basin region as well as the dependent areas. Desertification also creates the ideal conditions for the development of algal blooms that necessitate further filtrations of the water. This means that the populace will have to incur more costs in order to access water for basic needs. Soil erosion results in the collection of more soil particles in the water(Pereira, Cordeiry and lacovos 93). The interpretation is that it creates the need to have more filtration before it is usable. At the same time, increased salinization necessitates the ultrafiltration of the salts from the water, which requires the utilization of specialized and costly facilities. It also means that there will be more costs in the production of clean and safe water. With water being a necessary commodity in almost all domestic and economic activities, the economic implications of the effect of land degradation are unimaginable(Pereira, Cordeiry and lacovos 93). This is even before we incorporate the costs incurred by the destruction of infrastructure by corrosion and blockages. It is also important to note that the land degradation phenomenon has a direct negative effect on the industrial sector of the nation. This is because it threatens the energy production capabilities. The siltation of the reservoirs means that they hold reduced amounts of water. This means that the power production abilities of the power plant see reduction as they operate below their rated potential. If the reservoirs are not dredged, the siltation may create a deficit in the power production, which may result in failure to meet the region’s power demand slowing own the industrial sector. It may also mean an increase in power costs that will increase the costs of production. Conclusion The Murray-Darling water basin is an important feature in the nation of Australia. Its ability to produce large amounts of water makes it an ideal food production area. However, the region is under the threat of various forms of land degradation that threaten the amounts and quality of water as well as other capabilities of the region. The effects of this phenomenon are far reaching and pose a threat to the socioeconomic situation of the nation as a whole. It is therefore necessary to intervene and prevent the phenomenon from growing. Bibliography Discover Murray. The Murray: A River Worth Saving: The Murray Darling Basin.Murrayriver.com.au. N.p., 2015. Web. 29 Oct. 2015 Dregne, H. DESERTIFICATION OF ARID LANDS. Ciesin.org. N.p., 2015. Web. 29 Oct. 2015 Hawke, Graham. As El Niño Bites, It’S Time To Take Stock Of Our Water. IFLScience. N.p., 2015. Web. 8 Nov. 2015. Lawson, John. River Basin Management. London: Taylor & Francis, 2005. Print. Murray-Darling Basin Authority. Land Degradation: Erosion | Murray-Darling Basin Authority.Mdba.gov.au. N.p., 2015. Web. 29 Oct. 2015. Pereira, L S, I Cordery, and Iacovos Iacovides. Coping with Water Scarcity: Addressing the Challenges. Dordrecht: Springer, 2009. Print. Williams, M. A. J. Climate Change In Deserts. Print. Wohl, Ellen E. A World of Rivers: Environmental Change on Ten of the Worlds Great Rivers. Chicago: University of Chicago Press, 2011. Internet resource. Read More