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.
• Lesotho’s 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.
Surface Water Resources Of Lesotho
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Mohokare
6,890 sq.kms
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Senqu
28,847 sq.kms
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Makhaleng
2,911 sq.kms
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Senqu @ Seaka Bridge
RIVER SOURCES IN LESOTHO
WETLAND AT MOTETE AREA
MATSOKU AT HA SESHOTE
SENQU AT SEAKA
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 Lesotho’s groundwater is
dependent on seepage of rainwater.
YIELDS OF NATURAL SPRINGS IN LESOTHO
BY DISTRICT
DISTRICT
Mokhotlong
YIELD (l/s)
0.01 – 8.47
Botha-Bothe
Leribe
Berea
0.01 – 2.9
0.01 - 2.57
0.03 – 0.63
Maseru
0.01 – 1.98
Mafeteng
0.01 – 1.53
Mohale’s Hoek 0.04 – 1.57
Quthing
Qacha’s Nek
Thaba Tseka
0.01 – 2.7
0.02 – 1.14
0.03 – 5.41
Waiting for Groundwater
Pumping for Groundwater
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WATER QUALITY MONITORING
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WATER QUALITY FOR THREE MAJOR RIVERS OF
LESOTHO
Parameter
Senqu
PARAMETER
PARAMETER
Conductivity (µs/cm)
Conductivity
50-250
Conductivity (µs/cm)
Nitrates (mg/l)
(µS/cm)
Nitrates (mg/l)
Phosphates (mg/l)
Nitrates
0-0.08
Phosphates (mg/l)
(mg/l)
Phosphates 0-0.12
(mg/l)
Mohokare
Makhaleng
MOHOKARE
MAKHALENG WHO
WHO
SENQU
MOHOKARE
MAKHALENGguidelines
WHO
SENQU
50 - 250
70 – 450
0 – 250
0 – 2.0
0 – 0.08
0 – 1.8
70-45070 – 450 55-2500 – 250
50 - 250
0 – 2.0
0 – 0.08
0 – 1.8
0 – 0.77
0 – 0.12
0 – 1.8
0-12.6 0 – 0.12 0-1.8 0 – 1.8
0 – 0.77
0-0.77
0-1.8
1000
1000
1000
5
5
5 0.02
0.02
0.02
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

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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 Lesotho’s 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.
 Lesotho’s 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




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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 don’t 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
Conservation farming
Conserved drip 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.
Manhole oozing into Kelekeqe
Stream
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: toae@dwa.gov.ls
Tel: 22314569, 22317516