Sri Lanka has just experienced its worst drought for more than forty years. Reservoir levels fell to around 33% of capacity and many tanks dried up or are at low levels. Agriculture, particularly rice padi production has been decimated. One estimate suggested that by November 2016 only 35% of the nation’s rice padi had been cultivated and that over 1.2 million people have been directly affected by food shortages and loss of income. H.E.P. production was also affected and led to power cuts being imposed during the latter part of the year.
This was the picture for southern India and Sri lanka as of May this year:
You can find this map for yourself on the IWMI site (they are based in Colombo) and also on the Relief Web site; When it is amplified you will see that a large area of Sri lanka and Tamil Nadu are speckled brown (severe or extreme drought). This was a situation that had been developing for some time but it has come to a head in 2017.
Droughts can be categorised in a number of ways;
- When rainfall is well below normal/average levels
- When soil moisture content falls well below normal levels
- Where lack of rainfall leads to significant decline in agricultural production
- Where there is insufficient water to sustain the population
So what we now understand is that rainfall levels fell way short of normal; i.e. there was a rainfall deficit which affected pretty much everywhere apart from the south west of the island, as this map re-printed from Global Risk Insights shows:
With the exception of the North West around Puttalam it is the DRY zone which has been affected most. This is the zone which tends to rely on the North-East monsoon for its rainfall. So that means November / December. For the rest of the year high temperatures prevail. High temperatures lead to high evapo-transpiration rates (water loss from the soil and plants) and the soil dries out, storage tanks and reservoirs shrink.
source roar media network
So long as the monsoon rains return in November then all is well and the cycle continues supporting padi production, animal grazing and so on. However, what if the rains are much less than usual? Then soil moisture isn’t replenished and farmers run out of water. That is drought on 3 levels!
What is happening to rainfall?
So what happened to the monsoon in 2015/6/7 especially the North-East Monsoon? Without rainfall data for 2016/7, we can only speculate but anecdotally at least all the evidence points to a failure in the 2016 North East monsoon especially in the Dry Zone. This is borne out by the pattern of rainfall deficit shown on the rainfall data map where there is a high rainfall deficit pretty much everywhere, South-West excluded.
Possibly this is part of a long term trend. Looking at rainfall data for the period 2000- 2015 there is a suggestion that in the dry zone rainfall may be declining:
- The amount of rain falling between January and August is declining; for example: Batticaloa; Since 2009 7 out of the 9 years have experienced below the average rainfall for that period. The figures for Jaffna do not show the same trend BUT rainfall in that period only averages 371mm (2000-2015) anyway and given the high evaporation rates that is effectively a very dry season.
- For Jaffna and the North the NEM was lower than average 2005/6/7 and then again 2013/4
(Even then the paradox is that whilst rainfall levels may have not dropped that much in some areas the view of senior meteorologists is that the rains are coming in more intense bursts, that is shorter periods of more intense rain with longer hotter periods between them (attributed to a general rise in temperatures across the South Asia region giving rise to enhanced convective activity or storm clouds) So the significance of this is that the more intense the rainfall the more of it will run away(surface run-off) rather than soaking into the ground and recharging water tables.)
The other information we have to factor in is that 2015/6 were both strong El Nino years. El Nino is associated with suppressed convective uplift (the sort that stops rain clouds forming) 2016 also saw the Indian Ocean Dipole in negative phase so the Eastern Indian Ocean was warmer than normal which brought heavy rains to Western Australia but suppressed rainfall over southern India and Sri Lanka.
So the dark brown areas are areas of negative rainfall anomaly; i.e. much less raeinfall that normal. You may just be able to make out a big smear of brown across southern India and Sri Lanka. It means that rainfall was well down on the average for June and August.
The El Nino has weakened and is now in neutral as is the IOD but clearly the climate system has taken time to revert. What we won’yt know for a few months yet it how the October/November inter-monsoon period is going to react or what will happen to the North east Monsoon.
a. As of 20 August, more than 1.2 million people across 19 out of 25 districts remained affected by drought. Northern, North-Central and Eastern Provinces were reporting low levels of water for agricultural, drinking and household use. The failure of two harvests in 2017 has raised concerns for the food security and livelihoods of affected communities. (relief web).
b. Reservoirs fell to dangerously low levels, many at only 30% of normal levels
c. Plus increasing numbers of people are not getting either enough food or the income to buy food. The country’s rice harvest is likely to be down about 17 percent from the 4 million tons recorded in 2013, which would make it the lowest in six years. (IRIN). This has led to Sri Lanka having to import rice
d. There is a definite geographical pattern to the impact of this drought. It is the (mainly) poorer and more vulnerable communities of the North and East, still weakened by the effects of the Civil War, who are suffering most as this graphic taken from a local newspaper indicates;
What this drought has shown above all is that water insecurity has become a major issue for Sri Lanka.
Feeling the impacts
- Agriculture; without going into too much detail agriculture in Sri Lanka is not well advanced. 40% of cropland is down to irrigated rice production much of it at subsistence level and is characterised by:
- low levels of mechanization
- predominantly rain fed
- a significant % is at subsistence level
- costs are high and profitability is low
- land holdings are small
- there is too much reliance on traditional practices that determine the type of seed, water levels and harvesting patterns. Harvesting patterns based on scientific research are taking time to gain acceptance.
- water conservation is not high on the list of priorities
Plus there is not enough water transfer capacity to mover water from the wetter mountain zones into the dry zone to irrigate crops and support the population.
All of which makes Sri Lanka vulnerable to climate shocks such as the current drought.
2. Hydro Electric Power generation
During normal years when reservoirs are at capacity Sri Lanka can generate around 50% of its needs from HEP. Currently the country is supplying just 34% of its power supply from HEP meaning an increasing reliance on imported fossil fuels which pollute the environments and impact on an already delicate balance of payments situation for the country.
Plus there are other factors which impact on water demand to take into account:
- The population is now much higher than in the 1970s greatly increasing demand for water.
- Sri Lanka’s per capita water usage has picked up sharply over the past decades with rising living standards.
- Piped water, bathrooms with showers and flush toilets, industrialization, tourism, vehicle usage have all driven up water use.
Water Security: Practical Solutions
All the indications are that climatic hazard events will become more, not less frequent in the coming decades. So, what to do?
- The commonsense answer ( but not the most practicable in all probability) is to use less water. That could include:
- changing charging policies for water use; water tariffs are generally thought to be too low so this means that effectively raising the cost of water to the domestic consumer is needed to curb inefficient use and wastage. However, in Sri Lanka where significant numbers of people are already close to the poverty line (however that may be drawn) such a move will hit the poor hardest
- having a more effective metering system in place particularly where crop irrigation is concerned to ensure a more efficient use of irrigation water
- exert greater control over use of water by industrial companies and in the tourist sector
2. Conserve water
- develop efficient water recycling facilities; for example Colombo does not have a proper waste water treatment plant resulting in partially treated water discharged to the ocean. (source Water Sector of Sri Lanka report 2014). This is a crazy situation. Greater Colombo is bound to be a major water user with a high water demand. Why is the waste water simply flushed away when it could be recycled as it is in many other countries
- industrial pollution of water resources needs to be dealt with; inland waters in urban areas are polluted heavily with domestic sewage and industrial effluents It seems that in many cases domestic waste finds its way directly into rivers; people often use rivers as a latrine and all sorts of waste is dumped in surface streams rendering them unusable as these two images found in the Sunday Times show.
So here you can see untreated effluent running into the Kelani River from a local canal
and here is a fairly typical scene in a watercourse by a low income settlement
In rural areas with agricultural runoff pollutes rivers and streams. In urban over-crowded cities, there is biological contamination of ground water. Except for pipe-borne water supply, irrigation and hydro-power schemes, in general water resources in Sri Lanka are managed very poorly. Regulations are available to control most water related problems but enforcement of these regulations is lacking.
… and this is the point. Water is becoming an increasingly scarce resource. There is a real need to conserve existing supplies and re-cycle water effectively.
3. Develop exiting inter – basin water transfer schemes. In other words mover water by pipeline and channel transfers from the wetter areas to the dry zone. The Mahaweli River basin project initiated in the 1970’s was intended to take water from the mountains to the dry zone; and it does. But is that enough? Question rather than answer and obviously any addition to existing arrangements would be expensive. The question is; does the government even consider whether adding to existing water transfer schemes is worth investigating?
4. Innovative methods; harvesting rain water. I found this extract printed in the Daily Mirror 2016;
Water that falls on a roof of 1,000 sq m in Colombo (average rainfall is 2,000 mm) during a period of one year would be around 2,000 cubic meters (i.e 2 million litres or app. 400,000 gallons). The actual cost of this amount of water would be around Rs. 90,000. The rainwater that falls on the roofs of extensive buildings such as hospitals, schools, housing complexes etc. could be collected in tanks in the premises itself. Water thus collected could be used for numerous domestic purposes. Currently we use chlorinated water suitable for drinking to wash cars, water plants, clean toilets etc. Using rainwater for these activities would reduce water bills, save purified water, which could be used for drinking purposes. Once the collection system is installed there is no additional cost involved except on pumping of collected water to the main water supply system. (Dr CS Weerearatna Daily Mirror October 2016)
This is one simple idea which involves collecting rainfall from roofs and storing it in large tanks either fully or partially underground. The only costs involved are the installation costs plus the cost of pumping the water from the tank. Is this being promoted by the government? It doesn’t seem to be. But these are simple low-tech solutions, so it is surprising that so little is being done.
This article began by charting the development of the latest drought to hit Sri Lanka. Monsoons will fail from time to time, that is a given. Although we understand more now about why droughts occur we are powerless to stop them happening. All of which means that when they do occur it is important to have strategies in place to help people cope; to reduce their vulnerability to drought. Sri Lanka is not alone , in facing the dilemma of what to do and how to do it. Water security is an issue throughout South Asia. What this drought has done is bring into sharp focus the need to be planning now for the next drought or Sri Lanka will simply have to go through this crisis all over again.