Mitigation Strategies through IWRM By N. Toae –Hydrobiologist, DWA
Introduction Water is vital for drinking, sanitation, agriculture, industry, generation of hydropower, navigation, recreation, fish farming and countless other purposes. It is termed White Gold in Lesotho because of its economic value. We need to conserve water and manage it for the benefit of present and the future generations.
Lesothos main natural resource export is … WATER
Introduction cont… Floods cause the destruction of property and loss of life. Impaired water quality brings disease and death to humans and aquatic life. Droughts can also be a cause of starvation and famine.
PRECIPITATION Annual rainfall 500mm – 1200mm. The annual average of 720mm. 85% rainfall in summer (0ct-Apr). Snowfalls experienced in winter.
RIVER SOURCES IN LESOTHO The wetland (sponge) systems are sources of rivers in Lesotho, most of which are located in the highlands of the country. Wetlands are capable of storing water and slowly release this water into small streams that ultimately drain in to river systems. Over grazing and other development activities threaten the lives and capacities of these wetland systems.
Groundwater Most of groundwater is of good quality because of its natural purification processes. People in the rural areas of Lesotho depend on it for their daily life. Available data shows that water level in boreholes responds accordingly to rainy periods and droughts. Spring yield is also lower during droughts, down to drying up in some springs and it is high in rainy periods. This simply means Lesothos groundwater is dependent on seepage of rainwater.
WATER QUALITY FOR THREE MAJOR RIVERS OF LESOTHO ParameterSenquMohokareMakhalengWHO guidelines Conductivity (µS/cm) 50-25070-45055-2501000 Nitrates (mg/l) 0-0.080-12.60-1.85 Phosphates (mg/l) 0-0.120-0.770-1.80.02
WATER POLICY Rational exploitation and management. Access to portable water by all people of Lesotho. Protection of environmental aspects of water. Cognizance of international obligations. Stakeholder involvement. Water as an economic good.
Cause for concern Because of the fact that global water resources are more or less fixed while world population is very rapidly increasing, the competition on water between development and environment may cause local and regional disasters.
Effects of climate change on water resources Increased temperature Drying up of water bodies Intensified pollution of water resources Intensity and frequency of storm increases More floods and droughts
Prevailing situation – Pollution A water body has capability of cleansing itself called assimilation capacity. When pollution is beyond the assimilation capacity of a water body, it causes eutrophication. Results show that some of Lesothos water bodies are polluted already.
MOHOKARE DOWNSTREAM OF THETSANE INDUSTRIAL SITE
Prevailing Situation - Groundwater Most of groundwater is of good quality because of its natural purification processes. People in the rural areas of Lesotho depend on it for their daily life.
Greatest Challenges Availability of fresh water is one of the greatest challenges facing humanity at present. Lesothos need for water continue to grow wider in space and bigger in population. Growing developments use water massively thereby generating considerable wastewater that pollutes water resources. In the near future Basotho will be affected by shortage of water or pollution of water bodies or both.
Plan If the competition for water is transformed into partnership, the goal of sustainable development will be attained, as recommended in the world water forum of 2000. Integrated Water Resources management that includes planning and management of water resources should be employed. To achieve IWRM, there is a need for coherent national and where appropriate, regional and international policies to overcome fragmentation, and for transparent and accountable institutions at all levels. Develop new sources of water Increase water use efficiency and reduce water losses Operational hydrological monitoring and forecast systems
Integrated Water Resources Management The ways and means of evaluating and balancing supply and demand for water in a specific region. The assessment of measures which enable the reduction of demand and increase of available supply should be considered.
Supply could be: Precipitation or flash floods Permanent or seasonal flowing rivers and streams Dams, Lakes and reservoirs Groundwater Soil moisture storage in the unsaturated zone
Other Sources Recycled treated sewage Recycled treated industrial effluent Water transported from other locations
Parameters to mitigate Drought impacts Impacts on Water quality Flood impacts
Drought impacts mitigation measures Storage reservoirs for surface & groundwater should be constructed to store water to avail it when most needed for the benefit of all water users. i. Control gates should be regulated to supply according to demand. ii. Surface water reservoirs should be big enough to cater for siltation over an operational period of 500 years. iii. Each of the three catchments of Lesotho should have one or two reservoirs depending on their population.
Drought impacts mitigation measures cont… Conservation farming will conserve moisture & minimize evaporation so that crops dont need frequent irrigation and also minimize erosion. Conserved drip irrigation – this method irrigates crop by crop not wasting water on bare land thereby minimizing water loss. Controlled Allocation of water – consideration of soil type and crop type should guide quantity of water allocated for irrigation
Drought impacts mitigation measures cont… Telemetry system – strict monitoring of compliance to quantity allocated should be followed, e.g. use of data loggers measuring level upstream & downstream Water recycling – massive water users should be legally bound to have effective treatment plants and reuse their wastewater in their productions. Roof water harvesting – use of RWH tanks to store rain water will provide water to many people during times of drought
Water Pollution mitigation measures Pollution sources are mostly sewage related and in the lowlands. Time bound removal of septic tanks, manholes, etc. by relevant institution. Transparent and accountable institutional operations Wet Industries should be placed away from settlements to have enough land for their wastewater treatment plants Consolidate all environmental laws of Lesotho and introduce environmental courts dealing with environmental issues solely.
Pollution mitigation measures cont. Proper disposal of waste according to type and recycle that which is recyclable. Management of pollution should not be all penalties, include incentives for compliance. While implementing the polluter pays principle, charge should be on loads not quantity of effluent based on impact of pollutant, e.g. heavy metals should be more expensive as they are not biodegradable.
Flood impact Mitigation Measures Use of remote sensing to estimate rainfall from satellite images in three different spectral bands; infrared, visible and water vapor.
Flood impact Mitigation Measures cont… Produce and distribute to users a regular forecast bulletin containing relevant data, information, deterministic and Extended Stream flow predictions forecasts of river flow regime. Use of other media as early warning on the likelihood of a flood and advise accordingly. Set different alternatives and scenarios for managing the whole basin in a way that benefits all countries in the basin.
Kea Leboha Contacts: Department of WaterAffiars P.O Box 772 Maseru Email: email@example.com Tel: 22314569, 22317516