A guide for planners and managers - IUCN

FIGURE II-37.
PART II
Protected Areas for Small Islands
A major purpose of the Gulf of Mannar Marine Park (India) is to protect the chain of islands that parallel the coast.
Groundwater supplies. Where groundwater is being tapped, particularly on
small coral cays, water quantity and quality should be monitored carefully. In certain
areas the freshwater lens may fluctuate widely. Care must be taken not to deplete the
water supply to the point that dependent vegetation can no longer survive.
Sewage disposal. Sewage disposal should be carefully planned. Human wastes
may affect the nutrient status of the soils on some islands, with the consequence that
introduced species may be given a competitive edge over indigenous species adapted
to the nutrient-poor conditions. Any sewage outfall to the sea should be carefully located
in relation to tides and currents. Septic systems should be monitored for efficiency
(particularly if saltwater is used and coral is laid in absorption trenches). Septic
tanks and French drains should be placed at least 15 meters from wells to avoid
contaminating freshwater supplies. However, this distance is soil-dependent and
greater spacing (up to 45 m) should be required if land is available (see Clark, 1996).
Garbage disposal. Garbage disposal must be carefully planned. Biodegradable
materials can generally be dumped at sea, as long as currents are moving seaward
and garbage is dumped well off reefs and shoals. However, wherever possible, they
should be composted and used to enhance agricultural production. Visitors should
be discouraged from bringing glass containers and cans with tear-off tops. Managers
should be encouraged to seek lightly packaged goods and to use biodegradable
materials where possible. Dumping wastes on a large scale near islands may attract
225
Photo by John Clark.