Various activities on land conducted or advocated by humans have contributed to major ecological problems related to water bodies. Mining, livestock production, and other agricultural methods lead to severe water pollution. The main causes of the pollution are soil erosion and excessive use of chemicals in farming. This ends up in the marine ecosystems, causing disturbance to the aquatic lives. It is, therefore, paramount that water engineers and technicians come up with appropriate models based on the problem. Additionally, they should use the readily available model inputs to try and assess the effects of changes in land use on water bodies. The main objective of this review is to establish the hypothesis that modelling is an important tool in the assessment of the impacts of land use changes on water bodies. This paper, therefore, aims at testing this hypothesis by recommending some of the possible limitations as well as delimitations of using modelling as an assessment tool.
There is the need to address the problems of increasing nutrient and sentiment loads exported into water bodies. At the outset, land use is the human utilization of land by modifying the natural environment in terms of settlement schemes and other habitats. There is need to address and regulate these practices as they have posed many problems to water bodies. Land use is highly considered as chief terminology for city planners and developers who would wish to subdivide it into sections for various purposes. These subdivisions have had tremendous impacts on water bodies surrounding a city or town. Agricultural practices will eventually see the disposition of both Nitrogen and Phosphorus into the soil and the soil will be exported into rivers and / or oceans. Thus, capable modelling approaches are needed to evaluate accurately the impacts of human land use activity changes on water surfaces (Levin 2012, p.18).
Impact of Changing Land Use on Receiving Water Bodies
Each community engages its land in different activities. These activities end up affecting various recipients (rivers and other water bodies) strategic to the lands differently, depending on the type of activity adopted. There are many types of land use. Most of them usually depend on other types which may stand on their own. Most of these types usually make immediate impacts especially on water bodies around. It is because water is highly relied on by all individuals to carry out of their daily activities (Wayland et al. 2002, p. 195).
Residential Land Use
These are places with many buildings and houses which have been built specifically for people to live in. Such places may include settlement schemes and estates in towns and cities. Land use changes may be brought about by the change in the peoples’ population, level of affluence and the level of technology. With settlement schemes therefore, people might choose to concentrate in one area. This increases the population of that settlement. When population increases in a certain place, human activities, such as farming, mining operations, indiscriminate waste disposal as well as livestock grazing are likely to hike (Liu, Tong & Goodrich 2002, p. 27). Thus, it creates strain on the river systems surrounding the people as they cause catchment area erosion and ground water pollution. Besides, it also results in river sedimentation, augmented water acidity, increased turbidity and high nutrient loads in water.
Additionally, high populations may insinuate increased human pressures on land resources. Activities such as agriculture which heavily depends on land resources, end up altering land use, hence reducing the availability of factors such as rainfall (Arismendez, Kim & Brenner 2009, p. 250).
Industrial Land Use
The land set aside for industrial purposes is the land that is developed industrially. Here we find amenities such as factories and garages. Industrialization has over time been seen as the main drive towards land use change by many researchers. It brings about the concentration of human population within urban areas and the depopulation of rural areas. It is usually accompanied by intensification of agricultural activities on the most productive lands and the abandonment of marginal lands. Normally, effluents from factories and industries are channelled into rivers and other water bodies without treating them first. The effect of this action is that the acidity of the waters will increase to the extent of destroying aquatic lives as well as the people who surround the water bodies. The receiving water bodies will, therefore, be inhabitable (Owens & Collins 2006, p. 94).
Agricultural Land Use
When land is used for residential purposes, it is most likely to be changed into an agricultural amenity. In this case, the water bodies surrounding the area will be at risk especially due to soil erosion. If initially the land was set aside for recreational purposes such as parks, then changed into an agricultural hub, the chemicals used for farming such as Nitrogen and Phosphates will be washed and exported into the rivers. Subsequently, it alters the water pH hence affecting the water that could have served the community (Zhang & Wang 2012, p. 288).
Commercial Land Use
Some areas in towns and cities are set aside for commercial activities. In such places the amenities such as shops, offices, banks and open markets are likely to be found. Usually, there is a lot of waste materials such as polythene wrappers, plastic containers, steel cans that are thrown into rivers. These may disturb the marine ecosystems hence destroying aquatic lives. However, the impact of these amenities is not as serious as that of the changes in industrialization or agriculture (Zhang & Wang 2012, p. 286).
Recreational Land Use
This is the land which may be set aside for relaxation such as gardens, playgrounds parks and bowling places. These places do not usually cause disturbance to water bodies. Changing this use into something like agriculture or industrialization will therefore see the impacts of the adoptees befalling the surrounding water bodies (Tong & Chen 2002, p. 250).
Application of Modelling as a Tool to Assess Land Use Change Impact
It is important to address the problems resulting from nutrient loads in water sheds. This can only be done by the use of an effective assessment tool and software. Therefore, modelling seems the most appropriate method to me due to many advantages that it has for the life of a researching technician. First of all, when modelling is used in assessment of technology or science related scenarios such as environmental studies, it is referred to as scientific modelling. It has the capacity to integrate environmental problems with academic policies and presents a better procedure of assessing the extent of the problems (Misztal & Kuczera 2008, p. 32).
Advantages of Modelling as an Assessment Tool
There are a number of advantages associated with modelling as an assessment tool.
First, modelling uses readily available tools and information. It is therefore cheap compared to other analysis tools. This enables decision makers and researchers to understand key environmental issues which affect an area and contribute to changes in land use before implementing policies. This ensures applicability of decisions reached (Anbumozhi, Radhakrishnan & Yamaji 2005, p. 520).
Models are often viewed as useful tools especially when analysing key factors affecting a scenario, assessing their results and delivering transparent outcomes without bias. This is because they help in the integration of various system processes into a single unified framework and enable them to be analyzed without favour.
Models have also been seen to possess the capacity to accommodate multiple issues, values, scales and uncertainty considerations as well as facilitate engagement of key factors which play important roles in decision implementation (Brabec, Schulte & Richards 2002, p. 510).
The ability to be applied effectively in learning situations especially in interdisciplinary settings makes modelling a better process of learning. It is manageable because of the capacity to accommodate multiple values as well as engagement facilitation of stakeholders.
All the above-mentioned advantages are only possible because modelling provides a generic guidance to set up site specific model options for modelling in a range of conditions.
Modelling, unlike other analysis tools, provides additional and optional methodology to incorporate diagnostic as well as prognostic meteorological data (Musaoglu, Tanik & Kocabas 2005, p. 225).
All these, together with the appropriate procedures provided by modelling for evaluation of the results makes it a better tool for analysis and evaluation of the factors impacting on water bodies as a result of land use changes.
Disadvantages of Modelling as an Assessment Tool
There are also certain demerits associated with the use of modelling as a land assessment tool. Modelling is risky because it may lead to the increase of the complexity of the system as the scope of the study may overstretch beyond the expectations. Furthermore, the method is time consuming since there might be too much reparation of systems to suit the original desires.
In addition, the researcher may sometimes fail to engage the full model. When this happens, the full system is at the risk of failure since the system was incompletely designed (US Environmental Protection Agency 2010, p. 28).
As a final point, the researchers have shown the competency of the modelling method in assessment. For better result oriented research in the future, the modelling system stands out as the best alternative. For that reason, land modelling method has been recommended for analyses in the areas dealing with science and technology largely because of its extensive advantages.