Sunday, July 15, 2012
Erratic Rainfall in Sri Lanka Hitting Rice Crop, Power Production
A rice farmer walks across his field in Sri Lanka. ALERTNET/Amantha Perera
When it is full, the Parakarama Samudaraya irrigation tank in Sri Lanka’s North Central province is an impressive sight. With its waters gently lapping the shores, this ancient reservoir –which covers more than 20 sq km (8 sq miles) - lives up to its name, which means the Parakarama sea.
But these days, it might as well be renamed the Parakarama puddle. The failure of seasonal rains has caused water levels to drop so badly that by the first week of July the reservoir was at less than 8 percent of capacity, irrigation engineers reported.
Climate experts attribute the country’s wildly fluctuating rainfall patterns to the impact of climate change.
“What we are seeing is the combined effect of regional and global climate patterns changing,” said W L Sumathipala, former head of the climate change unit of the Ministry of Environment.
The lack of water at the Parakarama tank is a particular worry for farmers, who rely on it to grow their crops.
“We don’t have water to release for irrigation; we have not released water for irrigation for about two months now,” said R M Karunarathane, chief divisional irrigation engineer for Polonnaruwa District, which has responsibility for the Parakarama tank.
Polonnaruwa is one of the major rice producing regions of this island nation, and the lack of water is threatening to leave paddy fields dry and unproductive.
On July 9 and 10, farmers in the district held protests warning that as much as 16,000 hectares (40,000 acres) of paddy will be lost without irrigation water. The Sri Lankan government has already reacted to the likelihood of a large harvest loss by banning rice exports until the middle of 2013.
While Sri Lanka’s main rice cultivation period, from October to March, relies on rain, the secondary harvest between May and August is almost totally dependent on water from irrigation.
Last year, around 20 percent of the country’s rice harvest was lost due to heavy rains in the early parts of the year, although the same rains allowed for a better harvest in the second season.
The scarcity of water this year stems from the failure of the monsoon, which means that rivers cannot supply tanks like the 1,700-year-old Parakarama Samudaraya with sufficient water. According to Sri Lanka’s Meteorological Department, catchment areas like Kukulegama, Laxapana, Norton and Canyon in the central part of the country, where large reservoirs are located, had by June this year received less than a third of the rainfall received in the same period last year.
“It is the lack of rainfall that is the primary reason for the loss of water; the second is the hot weather,” said Karunarathane, the irrigation engineer in Polonnaruwa District.
Sumathipala agreed that the lack of rain was worsened by rising temperatures. According to the annual report of the Sri Lanka Central Bank, average temperatures have increased by about 0.45 Celsius in Sri Lanka over the last two decades.
Rising temperatures mean that whatever water is available in dry-zone areas like the Parakarama Samudraya evaporates quickly, according to Sumathipala.
“What we are seeing is that the dry zone is getting drier, while the wet zone (in the western
region) seems to be getting sufficient rains,” he said. But he warned that research has shown that the wet zone is also prone to flash floods as monsoon rains become shorter but more intense.
Sri Lanka faces a second major threat from the failing rains as well – the loss of hydropower.
“On a good year, we can manage to have around 42 percent of the electricity generation from hydro power. This year, however, it will be closer to 25 percent if not less,” said Thilak Siyambalapitiya, an energy consultant and a former engineer with the Sri Lanka Electricity Board.
The island’s power generation is currently over 85 percent dependent on thermal power using oil and coal, which when burned contribute to climate change. Also, with the rupee falling against the dollar in the last six months, the more the country becomes reliant on thermal generation, the higher the drain of foreign exchange and resultant pressure on the economy.
The cost increases in making up hydropower shortages with thermal plants are huge. The cost of a unit of electricity generated using hydro power is around 1.7 Sri Lankan rupees (about 1 cent), but switching to thermal increases the cost to 9 rupees (7 cents) for coal, 15 rupees (11 cents) for furnace oil and around 24 rupees (18 cents) for diesel. The government subsidises diesel generation by about 20 percent.
“The cost incurred will either have to be transferred to the consumers or the government has to absorb it,” Siyambalapitiya said.
Ironically, in 2010 Sri Lanka’s power generation capacity through hydro increased to over 50 percent due to heavy rains. The same rains also increased the secondary rice harvest in mid-2011.
The Central Bank annual report warned that the livelihoods of 1.8 million people dependent on agriculture, or between 8 and 9 percent of the population, were at risk due to changing weather patterns.
“The biggest impact Sri Lanka will face will be from changing rainfall patterns, because they can have multiple effects, from agriculture to power to pressure on the currency, but people still don’t take note,” Sumathipala said.
When the rains that feed the Parakarama Samudaraya irrigation tank failed, engineers like Karunarathane warned farmers in vain to cut back on their plantings for the year.
“No one listened,” he said.
Sumathipala believes that such disregard can cause difficulties not only for individual farmers but for the country as a whole.
“There is some recognition on the impact of changing weather patterns, but we need much better pre-planning now that the erratic rain patterns have been confirmed,” he said.
By Amantha Perera@AlertNet