Thailand, an important area for aquaculture. The objectives of the study were to assess the
aquatic status and its potential carrying capacity for pollution and to understand the ecosystem response
to human and natural impacts leading to a proposal for an appropriate zone management approach for
sustainable utilization of the area. Information on community-based utilization patterns was obtained
through surveys using questionnaires. Field conditions were monitored by 2-monthly surveys from
August 2004 to August 2005. The survey areas covered 12 stations in the middle zone of the Bangpakong
River, 12 stations at adjacent canal mouths that received pollution loads from a nearby community and
29 stations at pollution point sources. Results indicated that Bangpakong River was eutrophic all year
round. High nutrient loads from Ban Pho community continuously flow into the aquatic environment.
The highest concentration of NH4
+
nutrients came from crocodile farms (5,408 mg/m3
), whereas
maximum total loads (299×109 mg) during the year were from domestic sources. Total nutrient loads
varied temporally and were different among zones. Almost all nutrient levels were high during highloading
periods while the remediation potential was generally low. Land remediation potential with
respect to NH4
+
and PO4
3- was inexcess of 30 times more efficient in areas with comparatively high
flow rates and more mangrove vegetation. In terms of river-water remediation potential, the efficiency
of NH4
+ elimination was less during the dry period. It was observed that the Na Lang, Nong Bua and Yai
Loy canals were affected by some human and environmental impacts. These areas needed more attention
with regard to monitoring and management. In addition, focus should also be given to the areas around
the Pra Wet canal because of their low remediation potential during the dry period. Results of multivariate
analysis on the ecosystem responses indicated that functions of NH4
+
 and total suspended solids in the
aquatic system significantly influenced chlorophyll a changes. Based on the overall results, area zonation
of the Ban Pho Town was being proposed and problems were being prioritized. Moreover, the application
of integrated models suggested the need for better water quality control and/or management