1). Erosion causes on-site loss of agricultural potential as well as an off-site effect of downstream movement of sediment, that can result in floods and silting of reservoirs (Directorate Communication, National Department of Agriculture 1). Eventually these problems contribute to the limited distribution of quality food to individuals caused by a great loss of potential agricultural land (What Is Soil Erosion? 1). Natural activities are one of the many causes of soil erosion and unfortunately there is no way of preventing erosion from these activities.
But weak pavements will exhibit signs of failure in the form of wide cracks, ruts, poor ride quality and deflection. Because of this reason there is a need to evaluate the structural and functional deterioration of the flexible pavement periodically. Deterioration of pavement can be attributed to various factors like traffic, environment, materials properties and pavement thickness. Stability of pavement depends on subgrade properties which affect the mechanical characteristics of pavement. These factors affect the performance of the pavement in a complex manner.
According to FAO steeplands often pose specific problems to agriculture and the environment because the steep slopes and accidental relief result in shallow soils that are very prone to erosion and landslides. Most of the land degradation problems found in steeplands occur in gently sloping areas, but the difficulties become more severe as slope gradient increases (Shaxson 1999, p.1). In particular, the steeper the slope the more rapid are the land degrading processes of soil erosion, runoff and mass movement due to the effect of the earth’s gravitational field (Shaxson 1999, p.1). Runoff together with erosion is damaging soil productivity through loss of water and by removal of soil physical, chemical and biological consistencies (Shaxson 1999,
Ultimately, climate change is likely to have a negative impact on countries and make them increasingly difficult to meet urban and agricultural water needs. Among the challenges ahead, measures are already being taken for the mitigation of climate change with water supply and disposal. The recycling of wastewater can promote employment within irrigation systems. Treated wastewater and also surface runoffs can be deliberately percolated (groundwater replenishment) and then used again later. Flooding events can be mitigated through dykes or mobile flood protection systems.
Deterioration may be a result of several factors, including design, materials used, workmanship, environmental influences during construction and service life, and loads acting on the structure. (HANS) It has become vital to find a dependable and efficient technique for evaluating the condition of a structure at various stages of its life span. Condition Assessment of Concrete Structures Traditionally, visual inspections have been the most frequently
The process of extracting this resources usually involves digging up and excavating soil. During excavation one is bound to notice that, soil can greatly vary depending on the depth and breadth even within a small region. Having a deep understanding of the different kinds of soils and how they behave is therefore important in such excavation activities. Soil mechanics can help an engineer anticipate areas that may cave in or cause landslides during the resource extraction and come up with appropriate ways of preventing such disastrous incidents. Soil mechanics can also help civil engineers and geologist working on excavation sites identify areas with better prospects e.g.
Land pollution causes the land’s productivity and potential to decline to such a level that the purpose of utilising lands for building infrastructures, housings, services, agriculture, forestry and many more for the development of human being are no longer achievable (Prabhakar, 2012). Land pollution are resulted by some sources which are deforestation, mining and construction activities. Deforestation appears to be the major concern as once the land is converted into dry lands, it can hardly be made fertile again. Those areas inevitably end up as waste lands. Mining requires the removal of topsoil containing valuable organic matters.
Some of the common definitions of land degradation include the one presented by Reynolds (2001) which states that: ‘land degradation is a persistent reduction in the biological and economic productivity of terrestrial ecosystems, including vegetation, soils, other biota, and the ecological, hydrological and biogeochemical processes that operate therein’. Land degradation created a major threat to the world’s ability to meet the increasing demand for food and other services of the environment. It is a complex process which involves the interaction of the changes of biological, physical and chemical properties of the vegetation and soil (NRC 1994). Land and also soil degradation can be recognized and described through the physical, biological and chemical changes from some ideal state created by natural or man-made influences. Land degradation is the long-term loss of function and productivity of ecosystem which is caused by disturbances from the land which it cannot recover without human aid (Bai and others 2008).
There are also anthropogenic activities that contribute to landslides including heavy machine vibrations in the ground, irrigation, and deforestation that can make fragile slopes unstable. The composition and geological structure of the earth substrate or rock can influence to the frequency and type of landslide that might occur in a certain area. The natural weathering, as well as tectonic activity can affect the strength and cohesion of the earth substrate. The activity leads to make the soil structure vulnerable and easy to slip downhill that increases the propensity for landslide incident (Chen, 2006). According to the Mines and Geosciences Bureau (2010), with the changing weather conditions and amount of rainfall each season brings, we could categorically state the number of landslide occurrences is increasing.
The two major causes of flood are natural and man-made. Some of the natural causes are heavy rainfall and overflowing of the flood ways that leads to continuous flooding. Also, flooding can’t only bring severe damage to the structures, it can also kill trees and herbal plants that we need in our lives (Devalsam, 2011). Lu (2012) stated that large area of soil looses certain amount of topsoil because of two reasons, first is erosion and the other is heavy flooding. Flood causes some amount of topsoil to lose.