WATER RESOURCES IN LESOTHO INTRODUCTION Water resources are sources of water that are useful to human, plants and animals. They can be used agriculturally, industrially, for domestic purposes, recreationally and for environmental activities. These resources have to be well managed to avoid their scarcity in the future because they play a vital role in the environment. Water resources are divisible into two categories mainly: Surface water resources Underground water resources Each of these categories is part of the earth's water circulatory system called the hydrological circle and ultimately derived from precipitation which is rainfall and snow. The loss of the other is the gain of the other e.g. water on the surface may be lost by seeping into ground and therefore the ground would be gaining that percentage of water. SURFACE WATER RESOURCES They found in: Rivers Dams Rivers As precipitation takes place, some of the water infiltrates into the ground and percolates to water-table. Due to the steep ground, the water may flow from the high head to the lower head of the water-table. Eventually the volume of water at this area increases and spring out to ground surface because of high pressure generated, forming a channel of water. Due to erosion, this will finally form what is called a river. This mostly happens in the highlands because of their high relief hence why rivers in Lesotho flow from the highlands to the lowlands. Mohokare, Senqu and Makhaleng are examples of rivers that flow from the highlands to lowlands of Lesotho. Wetlands are form of tributaries of rivers in highlands hence why the river flow in the highlands is higher than one in the lowlands. River flow in the highlands is also high because of the high relief. Dams In Lesotho, dams are forms of reservoirs constructed to conserve water. It is formed from the collection of water from a number of different sources e.g. Katse dam uses water from Bokong and Malibamats'o rivers. They also consume water from precipitation that falls directly on the surface of a dam and from the inflow of water from surface run-offs. GROUNDWATER RESOURCES As water soaks into the ground, a percentage of it adheres to clay and sand to provide water to plants through their roots. This water is said to be in the unsaturated or vadose zone, most of vadose zones are covered with air rather than water hence why they are unsaturated. Then gravity continues to pull down the other percentage down through the ground. Finally, the water will reach the saturated area where all the pores are filled with water. These saturated and unsaturated zones are separated by what is called a water-table. The water at this area is held by a rock called an aquifer. All these constitute what is called ground water resources. The water at this area can be obtained through the following: a) Wells− they occur when the water-table reaches the surface of the earth. They usually form naturally due to high rainfall that intent to increase the level of water- table. b) Springs− they also naturally occur when the water-table reaches the surface of the earth, but they usually form as flow of water from cracks of rocks. c) Hand pumps− they are formed by drilling a deep hole into the ground until a saturated zone is reached. The water is then obtained using a pump. These groundwater resources have played a crucial role in water supply for both rural villages and urban centers in Lesotho. Use of developed and undeveloped springs as well as hand pump and high capacity boreholes are all contingent upon groundwater supplies. And Lesotho's long dry season and recurrent droughts, coupled with significant soil erosion and siltation of streams, use of groundwater reservoir provide an effective method of water supply. FACTORS AFFECTING WATER RESOURCES IN LESOTHO 1. CLIMATIC CONDITIONS Rainfall − As rain falls into the ground, some of the water will infiltrate and percolate down the water table hence increasing the water table level. This increases the amount of water to be obtained. Also, some of water may not infiltrate due fully recharged soil so it will run-off the surface of the earth, filling up rivers and dams. Snow − As snow melts, some of it will contribute to surface run-off and therefore increasing the amount of surface water. Some of the snow will infiltrate into the ground and therefore increasing the volume of water available in the ground. Temperature − temperature is one of the common factors encountered in Lesotho. As temperatures are high, there too much evaporation from the surface water resources therefore decreasing the water available. 2. PHYSICAL FACTORS Land use Construction of buildings and roads across wetlands reduce a number of wetlands which keep rivers flowing. Live overgrazing and tamping on the wetlands. Overexploitation of wetlands. 3. GEOLOGICAL FACTORS If the base of an aquifer is permeable or cracked, some of the water would be lost as it will penetrate through it. This would result in the shortage of water for the users. If the ground level is mainly composed of an impermeable rock, Most of the water would run off and therefore increasing the volume of water available on surface of the earth. While the underground water would be available in small volumes. ADVANTAGES AND DISADVANTAGES OF WATER RESOURCES Disadvantages Groundwater resources The moisture from the ground may be in contact with the foundation components and cause the engineering structure to collapse. If the volume of water available in the ground reduces, people using this water would not get enough water to satisfy their needs. If the water table happens to reach the surface of the earth on a farm area, it may disturb the soil structure of that area, resulting in the low chances of consuming good crops. Surface water resource If the water from the surface is used without treatment, it may cause illness to the users as it is exposed to the surrounding. It may be contaminated by pollution from the industries e.g. industries produce gases that may cause acid rain that will in turn contaminate water resources. During construction of Katse dam: i. Wild plants and animals were misplaced. ii. Arable land was destroyed. iii. Lively hood of people was changed. iv. Risk of flooding was also increased. Advantages Groundwater resources Water from the ground is obtained naturally filtered resulting in the reduction of cost for cleaning the water and the illnesses caused by contaminated water. Water from the ground also helps in the formation of rivers that are of beneficial to the environment e.g. for irrigation, for domestic purposes. Surface water resources They can be used for agricultural purposes e.g. irrigation Fishing Generation of electricity RECOMMENDATIONS Unleaded petrol should be used in order to reduce harmful gases that cause acid rain that in turn contaminate water. Also combustion of materials that produce harmful gases should be ended. Surface water should be well conserved as reduce its scarcity in the future. Forest plantation should be promoted as they reduce the amount of carbon dioxide in the atmosphere hence decreasing the amount of acid rain. Building of structures over wetlands should be ended as it reduces the amount of available water resources.