Human activity management in coastal zones

Human activity management in coastal zone of Sri Lanka: by L.W. Seneviratne,
P. O. Box 1138, Irrigation Department, Colombo 7, Sri Lanka
Tel: , Fax: , Email: dd_spp@irrigation.slt.lk

Sri Lanka is an island with a long coastal belt. The wet zone has 2600 mm annual rainfall and it extends from Chillaw to Matara. Coconut cultivation is predominant in highlands. Salinity is the natural problem in the coastal zone. Drinking water is tapped from the drainage sources. In February and August months salinity enters the water supply inlets due to its low water levels. Also salinity enters paddy fields destroying the cultivation.

Human activity is now imposing a high threat in controlling salinity. Sand mining in rivers is the major reason for coastal zone structural damage. Increasing level of building construction and hence making bricks out of sand has caused heavy extraction of sand from all available locations. The natural phenomenon of making and maintaining sandy beaches has now disturbed. Sufficient sand is not reaching the river sea confluence to maintain sandy beaches. Erosion in beaches has caused extensive damage to the railway line and houses. The beauty of the beach is lost when revetments are formed to protect the eroded coastal line. Mining limestone in the SW zone has again caused the loss of coral reef and death of valuable and beautiful variety of corals.

Village level teaching programs for the protection of environment is planned. But the human activity is increasing with tourist industry in this area. Chemicals also had caused death of corals. Effluent released from hotels, dwellers and factories have caused chemical damage and eutrofication in lagoons.

Coastal zone management is assigned to Coast Conservation Department. The traditional irrigation and drainage of water is assigned to Irrigation Department. There is a necessity to control bank erosion of rivers. People do not seriously feel the gravity of coastal zone management. Investors think about the profit only and not on the long-term effects of the construction work. Mangrove trees are now reduced. This amounts to rise in sea level in coastal zone. Prawn farmers converted lagoons into busy areas but the addition of biomass has affected bio diversity. In Northern and Eastern coastal areas erosion is low but many locations are affected by erosion of lime. A national program combining all investors are necessary to develop a strategy to preserve sandy beaches and water quality in line with economic development Fisheries, tourism, industries, agriculture, ports development and water quality have combined effect on management.