Environmental Risk Assessment for
the Upper Songkla Lagoon, 1999
Thaweeburus, Parichart Faculty of Environmental Management Prince of
Songkla University
Schaefer,
Alois, Prof., Institute of Biogeography, University of
Saarland, F.R. Germany
Ratanachai, Chatchai Asst. Prof.,
Faculty of Environmental Management Prince of Songkla
University
The 8th
International Conference on the Conservation and management of
Lakes
(17-21 May 1999),
Copenhagen,
Denmark
Abstract
Regarding the
original of the lagoon, its formation could have occurred at least 5,000
years in the phases of Older Peron Transgression and Younger Peron
Transgression. Thale Luang can be ecologically characterized by a
saprobic stage evaluation based on WQI using factor analysis, showing
different level of higher saprobic stage in the eastern than western
part. The relations clearly illustrate that light is the most importance
limiting factor. On the other hand , the ecological characteristic of
Thale Noi was evaluated by the tropic state index. The TSI was then
developed based on factor analysis, and indicated seasonal patterns of
less to high eutrophication in the overall limiting factor seasonal
pattern play a significant role in the ecological state of water.
Bioindication using macrozoobenthos and macrophyte is discussed in
biogeographical aspects was performed. The sampling site were classified
into three groups—eastern, middle and western parts of the
lagoon—according to the cluster, coincidence, and factor analyses.
Hydrological parameter showed direct impact on lagoonal macrozoobenthos
dwellings, while seasonal variations were seen less prominent. The
Songkhla Lagoon can be classified into five main risk areas : 1) the
connection of Thale Noi and thale Luang, 2) the western part of lagoon,
3) the eastern part of lagoon, 4) the lower part of the lagoon and, 5)
the exchange point between lagoonal and sea water.
Keywords :
environmental risk assessment, water quality index, tropic state index,
bioindication
