Geoscience Reference
In-Depth Information
cleared land (including logging) and oil palm plantations. The major sources
of sediment to coastal waters are found along the northeast coast of Sabah
(including Kinabatangan River).
The actual sediment concentration at an offshore location depends on
the sediment load and water exchange. The areas most influenced by high
suspended sediment concentrations are Tawau and Indonesian bays. Darvel
Bay is influenced in areas immediately adjacent to the source, in contrast
Labuk Bay and the Sulu Sea have high concentrations most of the year. It
is highly likely that the concentrations in these embayments have increased
due to land-based activities. Along the coastline towards the South China
Sea and towards the Sulu Sea, an area 5-10 km in width is influenced.
Comparing the sediment concentration and the coral reef distribution,
it is found that in areas with high concentrations, either no coral reefs or
only poor quality reefs were found. Likewise a correlation between high
sediment concentrations, mangrove forest and prawn trawling grounds was
found.
5. Results on Pollution Loads and Coastal Distribution
Pollution loads from land depend on the nature and extent of industry, pop-
ulation and agriculture present in each catchment, and also on the distance
from the coastline and runoff quantity. In addition, biological processes also
affect the concentrations.
Heavy industrial polluters are located in or around major cities and
growth centers. Population concentrations in urban areas generate signif-
icant amounts of BOD, TN, TP, and in particular
E-coli
.Agriculturalor
cultivated areas such as oil palm plantations are a significant source of
nitrogen and phosphorus.
Pollutants tend to accumulate in semienclosed areas, such as several
of the bays. In general, calculated concentrations meet water quality stan-
dards, but the assessment needs to be made in greater detail.
6. Discussion and Conclusion
Through the baseline data collection and analyzes as described in the above
sections, a detailed understanding of the issues relating to Sabah's coastline
has been established, allowing management objectives to be set. Threats to
mangrove forests have been identified in terms of clearing and reclamation,
thus protection of mangroves can be considered a management objective.
