Increased flooding:

Many causes, little prevention

by Manjula Fernando

Although the recent calamity in Colombo and Gampaha Districts was attributed to the torrential rains triggered by the cyclonic condition in the Bay of Bengal, the experts point out other factors which perhaps intensified the ''abnormal flooding'' and disastrous consequences.

They urge the authorities to initiate a careful study of the areas inundated early this month, amidst indications that some areas normally affected by floods have been spared this time, while new areas were submerged.

According to the Disaster Management Centre, five towns in the Colombo and six in the Gampaha Districts suffered severe flooding since May 15. The suburban towns affected in the Colombo District were Kaduwela, Angoda, Kolonnawa, Wellampitiya and Kotikawatte. These towns lie on the lower flood plains of the Kelani river.

According to the Megapolis and Western Development Ministry, there are 5,600 illegal constructions including business premises along the Kelani river within the Colombo District.

Reasons

The towns inundated in the Gampaha District were, Katana, Gampaha, Ja-Ela, Biyagama, Kelaniya and Dompe. They were affected due to the overflowing of the Attanaagalu Oya.

The irrigation officials and disaster management officials said the flooding in Colombo was a result of the heavy downpour in all the catchment areas of the Kelani River, namely, Castlereigh, Norton, Canyon and Luxapana. The upper and lower catchments received record rainfalls throughout the week from May 15 to 20, with some areas receiving nearly 350 mm within a couple of days.

The Irrigation Ministry Secretary R.M.W.Ratnayake said the intensity of the rainfall was such that it was natural for water levels of rivers to rise and overflow, causing severe floods.

The Nagalagam Street flood gauge reached seven feet by Tuesday, May 17, indicating a 'major flood' according to officials. When the gauge reaches four feet it is considered a 'minor flood' and when it climbes to nine feet, it indicates a 'critical flood' level.

A man wading across flood waters with his belongings

Listing out the causes for the major flooding in Colombo and Gampaha, the Secretary said the foremost reason was the heavy and concurrent rainfall in lower and upper catchment areas of the Kelani River. Next reason, he said, was the intensity and duration of the rain.

After ten days of the disaster, flood waters in certain areas were yet to recede. Water remained clogged in the Sedawatte, Wennawatte and Angoda areas due to the blocking of anicuts by washed up debris, mud and polythene.

For the residents of Meetotamulla, the floods invited a different type of woe. The river overflow was contaminated by a thick black garbage ooze, thus enveloping the entire area with an unbearable stench.

Jagath Gunawardena, an environmental law expert said the officials cannot wash their hands off by blaming the disaster on the weather gods. "The solution must begin at the catchment areas itself," he stressed.

The forest cover in the central hills, including the catchment in the Kelani River has fallen drastically to 15 % - 20 %. This has pushed the surface water absorption to a minimal level. More than the intensity of the rain, this factor contributed to the surface run off, causing the river levels to rise dangerously, he opined.

He warned that such abnormal weather patterns would be the order of the day, due to global warming and other adverse phenomena. Therefore, the country must prepare for such calamities in the future.

"We need to begin re-forestation in the catchment areas as an urgent mitigation measure and stop ad-hoc clearing of wood-cover and development activities in the central hills.

These areas were preserved by the ancient kings and even the colonial rulers for a purpose", he pointed out.

Gunawardena said filling of wetlands was a major issue in the Colombo District and filling water retention areas 'above' ground level has aggravated the problem.

Expedient expansion and excavation of waterways, he stressed, can also aggravate flooding when the river rises dangerously high. If the waterways are below sea level the river water can flow back through these canals to low lying areas during torrential rains.

Mitigation measure

He said it is the same with digging up deep pools as in Thalawathugoda, as a mitigation measure to city floods. He opined that paving and carpeting urban roads should happen according to strict regulations heeding surface run off during heavy rains.

"It isn't correct to say Colombo city was saved during last week's floods.

There were flash floods in Colombo, but fortunately it was on Sunday (May 15) and there were no heavy traffic to clog the roads and highlight the plight that might have been," he said.

Gunawardena said, illegal settlements along the river bank and the lower flood plain of the Kelani River was an issue the authorities should look into, but a similar, if not an even bigger threat is posed by the construction of business establishments in the area. "It should not be conveniently ignored by the authorities."

A spokesperson for the Disaster Management Centre, said, the flood affected residents will be allowed to return to their homes soon after the water levels recede and re-location of them in safer areas will begin later on, as part of a major long term plan.

Emergency meeting

President Maithripala Sirisena in an emergency meeting to discuss disaster relief and long term plans for resettling the affected people a few days back said, the people should not be allowed to go back to areas in the risky lower plains of the river that go under water after every thunderstorm.

The spokesperson said, there will not be any immediate restrictions on the flood affected to return to their houses, but under the Ministry of Mega polis and Western Development , plans were afoot to build housing blocks for people living in the Kelani river flood plain. Low income groups are attracted to this area owning to the cheap real estate rates.

The people have begun to pick up their lives from square one, unfortunately, not from the point they left on May 15. They have to re-build from scratch - from pillow to mattress, and schoolbook to school uniform - everything has to be acquired. Hence, it may not be the best time to render them homeless once again.

But the lessons learnt should not be forgotten. These people too have the right to a decent life.

The authorities now face the challenge to walk the talk and find the reasons than that which meets the eye for the major flooding in the Colombo and Gampaha districts.