1.1 BACKGROUND OF THE STUDY
The development of soil erosion began when man settled down and started turning pasture land into farmland. The intensive exploitation of the land disturbed the natural soil vegetative cover and exposed its, surface to the effect of erosive agents and to introduce such forms of agriculture that did not destroy the land the devastation of land by erosion often led to the down fall of civilization e.g in Mesopotamia Syria, China and else where.
According to Robert. M. (1984), Erosion is manifested by the determination of soil surface effected by exogenous forces, especially water. Ice wind and, man as the significant anthropogenic factor. The disturbance of soil surface is accompanied by the removal of the detached soil particles by the force of kinetic energy of some of the erosion agents, namely water and wind and the deposition of this matter with a decrease in this energy. Erosion is caused by surface num off and result complex natural process. Water erosion is caused by precipitation. Areas with a low precipitation usually have a small surface num off because precipitation water infiltrates into the soil is consumed by vegetation erosion which may also be broadly cause by a natural factor organ.
It can also be carried by improper channeling neglect of natural sewage systems and obstruction of naturally sewage by buildings. Form land and other unplanned structure causes a great deal of damage.
Although the nature of soil within the area under consideration is mostly sandy with a very low water storage capabilities. Practical observation orchestrated form visit to those site prone to erosion have shown that their may be possibility of erosion if the nun off water is not properly channel e.g the nature of the soil. In sandy soil they can form a very good soil material but danger exist if the water table is near or surface nun off is not adequately channeled. The sandy easily eroded a way from it position their by causing or may lead to fully erosion.
Furthermore, erosion is seen as one of the most serious defects in contemporary residential buildings, it is observed here that apart form it causing rapid destruction of structure / buildings, it also result to severe damage to the soil and in severe case it adversely affect the health of the occupants.
1.2 STATEMENT OF PROBLEM
A certain condition or factor can make a soil or structure / building to loose their Sharpe effectively or ineffectively attain their maximum structural physical and economic life span. It has been seen that a number of fact observed to be responsible for the in-adequate or in-appropriate functioning channeling of sewage surface nun off water at the due time. These in turn expose the building site to the danger of erosion which accelerate their dilapidation. Among the factors or improper channeling / neglect of natural sewage system and obstruction of natural sewage by building without following the local authorities rules dropping of refuse in the drainage ways. Erosion plays a critical role in dilapidation of building and visible in construction industry as one of the most serious defect in contemporary residential buildings. All soils can suffer erosion but some are more vulnerable than others. Soils with dispersible subsoils, for example, are subject to serious erosion by funneling and gully formation.
1.3 RESEARCH AIMS AND OBJECTIVE
The major purpose of this study is to determine. The effective way of controlling erosion in a construction site prone to erosion problem.
1) Identity the various causes of erosion in building sites.
2) Examine the appropriate materials and (new and old) used in controlling the erosion.
3) Determine the most appropriate materials and techniques required for the controlling it.
4) To recommend measure if implemented will lead to effective control of erosion in a construction
1.4 RESEARCH QUESTIONS