BMP to minimise global warming impacts


Sri Lanka has its share of environmental degradations, caused by human interactions with nature directly with many uncontrolled human activities and land-use practices. The irony of it all is that while south was experiencing floods in the recent past, north continues to experience drought that had persisted for a long time; affected people living in both these areas are left facing serious challenges. Lack of preparedness of the people has caused the situation to get worse, while the authorities react after the event with their disaster management programme. As the proverb “a stitch in time saves nine” goes the authorities should sort out problems with Best Management Practices (BMP) as they occur; it would  save extra efforts later and avoid disasters or at least minimize its impacts on the people.

In Sri Lanka, global warming has created havoc many times on a regular basis and every Sri Lankan has to share the blame for their lack of preparedness to face the resulting disasters; where people living in coastal areas are striving to keep pace with coastal erosion and local relative sea-level rise; elsewhere in the island people are repeatedly confronted by natural catastrophes such as cyclones, riverbank erosion, surface and groundwater pollution, air pollution, droughts, wetland loss and floods.

Drought occurs when there is a prolonged period of abnormally low rainfall, leading to a shortage of water. Based on experience gained in the north during civil war years with limited facilities available people were motivated to work together to keep lifeline agriculture activities going and the impacts of drought was mitigated through careful planning and management process before the onset of the drought. Conservation of water through careful planning by restoration of bunds of surface reservoirs and drainage canals particularly in the peninsula helped to reduce drought considerably. It was out of necessity with proper management of water resources produced results. Many practical steps were taken by renovating and repairing surface reservoirs identifying actions to be taken to reduce potential drought-related impacts before drought occurred. It began with mobilising people and supplying them with adequate data to make informed and equitable decisions at village level during the process. Then narrowed the focus of study by identifying high priority drought-related impacts that are relevant to the user’s location. Took remedial actions to reduce the potential for the identified impacts to occur in the future. Various agriculture and other sector experts who understand the underlying environmental, economic, and social causes of the impacts assisted the farmer groups. Finally, utilized all feasible, cost-effective, and equitable information and actions were taken to address the identified causes. In this manner, true drought vulnerabilities were addressed in a period of three months and subsequently reduced drought-related impacts and risks. Therefore with proper management could reduce the impact of drought and it is this holistic management that is needed in the country. For any region is to be developed to make a contribution to the national economy, a proper distribution of available water must be ensured to them and not as at present let destructive floods to occur in the south while north is facing drought. Thus as reported in an earlier posting in Northern Breeze a proper Water Management Plan (WMP) could minimise water pollution, prevent flooding and reduce the impact from droughts, for it is a water related environmental problem magnitude of which is very much dependent on land-use practices in the catchment areas of the surface reservoirs.

While the annual floods are anticipated occurrences and desirable for overall growth of the economy; the low frequency floods of high magnitude like that occurred last week down south are destructive and cause serious threat to lives. Floods occur when the amount of runoff exceeds the carrying capacity of natural and constructed the drainage system and from overflowing rivers. With flood control measures which are mainly limited to building earthen embankments and drainage require proper maintenance. The lack of proper design and construction of a flood control facilities caused floods to occur in Diyagama, Kalutara last week. In the past during flooding the water levels in the Kalu Ganga would increase, as the water levels in the connecting Panala Canal rose, with it increased the water levels in the Bolgoda Lake near Panadura. To halt this rise in the water levels in the area, a bund was constructed to control the excess water flowing from the Kalu Ganga and by releasing water collected in the area above the bund in a controlled manner to the Bolgoda Lake, the flow of water to Panadura was controlled ensuring the area does not flood. Later the Southern Expressway was constructed on several areas of farming land close to this bund. The initial plan was to construct the expressway elevated on concrete stilts over this farming land; but the haphazard construction resulted in creating another bund for the Southern Expressway. Last week saw the people living in Diyagama inundated by the floods as they were trapped between the Panapitiya bund and the expressway bund, as the area was turned into a basin and gets filled with flood water during heavy showers. At the time of construction the people did protest and were able to get the smaller width of culverts at the bund was increased. Earlier before the highway was constructed water levels rose during the monsoons and decreased quickly; whereas now levels increased higher and had to wait for days as it could only flow through several culverts set out by the expressway.

The total amount of damage to economy, crops, and infrastructures due to floods has been steadily increasing in the country; because it is very clear that flood control measures taken by the authorities have not made any significant impact in terms of reducing the flooding tendency nor the total damage caused by floods. This point is well illustrated by another incident that occurred during the floods this week, where authorities wanted to destroy the Baddegama Bridge with explosives to allow smooth flow of water from Gin Ganga, as the old bridge was clogged up with logs and debris that were floating along the river accumulating upstream of it; that was caused by the floods bringing with it logs and debris from illegal deforestation taking place upstream; timely maintenance and preventive actions from authorities would have prevented it. Not surprisingly, the affected Halpatota villagers opposed destroying the bridge on the grounds that it would server their alternate route out of their village and have adverse impact submerging many houses along the downstream river banks.

Flooding is a natural phenomenon, which cannot be prevented. Complete flood control is not in the interests of most farmers. The flood control measures and policies should be directed to mitigation of flood damage, rather than flood prevention. The obvious question is despite all the money being spent to repair damages caused by flood disasters why is the flooding tendency increasing, and what can be done to reduce such damage in the future? The answers to these questions lie in understanding of the long-term factors contributing to increased frequency and duration of floods. Once the causes of the problem are determined, then preventive measures can be taken to reduce future damage caused by floods. To this end authorities must educate the people of the dangers of meddling with the environment to change the mindset of the people. Resources should be allocated to help people adopt a life style that is conformable to their natural environment. Indigenous solutions through changing the housing structures and crop patterns can help reduce flood damage. Moreover, with good governance curbing all illegal practices utilizing appropriate environmental laws, acts and ordinances will reduce any environmental degradation, necessary to achieve sustainable economic development. In addition, implementation of an improved real-time flood and drought control warning system can reduce damage caused by floods. A greater understanding of the processes that contribute to increased flooding tendency, however, can help to mitigate the adverse effects on human lives, environment, and economy. For example cultivation along mountain slopes require proper control and guidance from authorities and other activities like deforestation and mining activities in certain cases be banned as they have been identified as causing the landslides during floods in the process bringing more miseries to the people.

The flooding tendency could be minimised if both authorities and people adopt Best Management Practices (BMPs) as solutions to flooding problems and change their mindset by understanding the long-term factors that contribute to increased floods. These factors include: unplanned urbanization, soil erosion, local relative sea-level rise, inadequate sediment accumulation, sinking and compaction of land, riverbed aggradation, cultivation along mountain slopes, mining and deforestation. BMPs proposed are floodplain zoning, planned urbanization, restoration of abundant channels, dredging of rivers, increased elevations of roads and village platforms, building of efficient storm sewer systems, establishment of buffer zones along rivers, conservation tillage, controlled runoff near construction sites, adjustment of life-style and crop patterns, good governance, and improvement on flood warning or preparedness systems; so designed to reduce the run-off,  increase the carrying capacity of drainage system, and increase land elevations.