The majority of population in the study area majors in agriculture,
although its productivity is relatively low. The agricultural activities include
traditional paddy farming, dry land farming, and fruit/vegetable
production (Mance, 2007). Spatially, the study area is districted into 3
subareas according to their environmental and administrative conditions.
Temporally, wet and normal seasons are considered in planning
agricultural activities. Moreover, the agricultural activities produce a
significant amount of non-point source pollution. Nitrogen, phosphorous
and sediment in runoff from agricultural activities degrade the
quality of the waterways, and result in soil erosion and environmental
deterioration (Mance, 2007). Therefore, it is desired by the decision
makers that nonpoint source pollution from various agricultural activities
be controlled in order to sustainably develop the local economy.