Water cycle and WRM in changing climate in Sri Lanka
Water cycle and WRM in changing climate in Sri Lanka
Water cycle and WRM in changing climate in Sri Lanka
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<strong>Water</strong> <strong>cycle</strong> <strong>and</strong> <strong>WRM</strong> <strong>in</strong> chang<strong>in</strong>g<br />
<strong>climate</strong> <strong>in</strong> <strong>Sri</strong> <strong>Lanka</strong><br />
S. B. Weerakoon<br />
University of Peradeniya, <strong>Sri</strong> <strong>Lanka</strong>
Direct impacts on water <strong>cycle</strong><br />
experienced<br />
More extreme events –<br />
• extreme ra<strong>in</strong>fall <strong>in</strong>tensities<br />
• less wet days <strong>and</strong> warmer<br />
temperatures<br />
Jaffna<br />
River bas<strong>in</strong> boundary<br />
Ra<strong>in</strong>fall gaug<strong>in</strong>g<br />
station<br />
Mean Annual Ra<strong>in</strong>fall (mm)<br />
‣5000<br />
4000 – 5000<br />
3000 – 4000<br />
2000 – 3000<br />
1500 – 2000<br />
1000 – 1500<br />
500 – 1000<br />
Tr<strong>in</strong>comalee<br />
Batticaloa<br />
Colombo<br />
Galle
Changes <strong>in</strong> water <strong>cycle</strong><br />
Frequent high ra<strong>in</strong>fall <strong>in</strong>tensities<br />
frequent floods<br />
l<strong>and</strong>slides<br />
damages to hydraulic structure<br />
crop failure<br />
soil erosion – <strong>in</strong>fertile l<strong>and</strong><br />
<strong>in</strong>fertile l<strong>and</strong>, sedimentation,<br />
e.g. March is a dry month ion average but heavy<br />
ra<strong>in</strong>s have lashed <strong>Sri</strong> <strong>Lanka</strong> this year 2008.<br />
Inundation has displaced many people (4 died, 7,000<br />
displaced)<br />
Paddy harvest has been affected
Changes <strong>in</strong> water <strong>cycle</strong><br />
Less wet days <strong>and</strong> warmer<br />
temperatures<br />
soil moisture deficit<br />
High ra<strong>in</strong>fall <strong>in</strong>tensities<br />
Soil erosion <strong>in</strong><br />
mounta<strong>in</strong>ous regions<br />
Soil <strong>in</strong>fertility <strong>and</strong> soil<br />
moisture deficit –<br />
Tea <strong>in</strong>dustry is vulnerable<br />
to <strong>climate</strong> changes
<strong>WRM</strong> under <strong>climate</strong> change impacts<br />
Disaster mitigation - vulnerable population <strong>and</strong> areas<br />
for flood hazard, l<strong>and</strong>slide hazard have <strong>in</strong>creased.<br />
• Flood mitigation measures are required<br />
• Flood warn<strong>in</strong>g, flood control, flood proof<strong>in</strong>g, etc.<br />
Rice productivity- paddy is cultivated by irrigation<br />
• storage based irrigation systems are strengthened<br />
• flood dra<strong>in</strong>age to prevent <strong>in</strong>undation of low l<strong>and</strong> farm l<strong>and</strong>s<br />
Reliability of hydropower - 40% energy by HP (2005)<br />
• storage reservoirs based HP schemes aga<strong>in</strong>st run-of<br />
of-river HP<br />
schemes<br />
Susta<strong>in</strong>ability of reservoirs - <strong>in</strong>creased sediment <strong>and</strong><br />
debris <strong>in</strong>flow<br />
• catchment l<strong>and</strong> use management for soil erosion control
Reservoir cascades along major rivers
Reservoirs for m<strong>in</strong>or irrigation systems<br />
Number of irrigation reservoirs > 12,000, 1<br />
a total storage capacity of 0.43 km 3 , exists where the annual ra<strong>in</strong>fall <<br />
1500mm with a high seasonal variation <strong>and</strong> with an annual potential<br />
evaporation of about 1700mm, for WM for paddy cultivation <strong>in</strong> the dry<br />
zone for two seasons per year.<br />
No of reservoirs<br />
Capacities of reservoirs (MCM)
Sediment issues <strong>in</strong> Rantembe HP Reservoir<br />
Catchment Area<br />
3118 km 2<br />
Gross Storage<br />
7.1 MCM
Initiatives<br />
The centre for <strong>climate</strong> change studies <strong>in</strong> the<br />
Dept. of Meteorology (s<strong>in</strong>ce 1999 )<br />
http://www.meteo.slt.lk/cccs.html<br />
The major functions : Research <strong>in</strong>to cc <strong>and</strong> related issues,<br />
monitor<strong>in</strong>g <strong>and</strong> model<strong>in</strong>g of cc, Information gather<strong>in</strong>g <strong>and</strong><br />
dissem<strong>in</strong>ation, documentation services, establish<strong>in</strong>g l<strong>in</strong>ks<br />
<strong>and</strong> representation with relevant <strong>in</strong>ternational agencies<br />
Involvement of research community CC<br />
studies<br />
Universities<br />
Research <strong>in</strong>stitutions<br />
NGOs (e.g. Foundation for Environment, Climate <strong>and</strong> Technology)
Way forward<br />
Information (data) <strong>and</strong> tools<br />
• Advancements <strong>in</strong> real-time data acquisition systems<br />
• Advancements <strong>in</strong> modell<strong>in</strong>g (hydrometeorology, hydrologic,<br />
l<strong>and</strong> surface, drought, …)<br />
Awareness <strong>and</strong> expertise<br />
Capacity build<strong>in</strong>g<br />
Susta<strong>in</strong>able <strong>WRM</strong><br />
for prediction of flood risk levels,<br />
flood warn<strong>in</strong>gs, l<strong>and</strong>slide warn<strong>in</strong>g based on ra<strong>in</strong>fall estimation<br />
<strong>in</strong> advance<br />
Prediction of drought months <strong>in</strong> advance for decision makers<br />
Seasonal water management (reservoir operation, etc.)
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