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Asian Journal of Agriculture and Development (AJAD) - Call for papers!

Influences of land- uses on surface water quality in Namtha River, Luangnamtha District, Lao PDR

(Bangladesh), Master of Science in Environmental Science (University of the Philippines Los Baños)

Thesis Abstract:

This study was conducted to evaluate the effects of land use to water quality through an analysis of the water quality index for the protection of aquatic life and water quality index of human impact in the Namtha River. The survey area was divided into four sampling points along the upstream, midstream, and downstream of the river. Data collection was done in June 2016, which coincided with the first month of the rainy season. Results of the study revealed that built-up, lowland, and upland agricultural areas were the main land-use types. Changes in land uses in 2000–2007 were smaller than changes in 2007–2013 in built-up, lowland agriculture, and upland agriculture.

Values of key water quality parameters in each sampling point along Namtha River were assessed and compared to the Lao National Environment Surface Water Standard of 2009. Data revealed that almost all of mean values of each parameter fell within the standard except for EC and DO. In the same manner, these parameters were assessed against the proposed MRC water quality criteria for the protection of human health and aquatic life. Excesses were only observed when compared with the MRC water quality criteria for human health. Not one water quality exceeded the criteria for the protection of aquatic life.

Regression and correlation analyses between sources of pollution and water quality parameters showed that pollution from households, commercial services, and organizations were positively or negatively related with pH, NO3, NH3, and COD but not related with DO and EC, while pollution from production activities as rubber productions, slaughter house, pig farm, and manufacturing industries were positively or negatively related with all parameters. Similarly, land use types and water quality were analyzed and showed that land uses were positively related with pH, and either positively or negatively related with other parameters, except with EC. Moreover, slope of the area and population density were also positively or negatively correlated with water parameters. Analyses between water quality parameters and respondents’ knowledge, attitude, and perception about the Namtha River indicated that the respondents’ perceptions were positively correlated with the river’s pH and DO. Their knowledge and attitude about the river had positive relationship with the river’s EC, and their attitudes on the river were positively correlated with the river’s NO3.

The results of the investigation of current status of the Namtha River showed that three villages covered in the sampling points were within acceptable limits. Existing land uses adjacent and surrounding Namtha River could contribute to the degradation of water quality. With these realities, management strategies to save and sustain water quality of the Namtha River in particular and some other rivers in Lao PDR in general, were recommended. These included the strict implementation and enforcement of laws and regulations on comprehensive land use planning, wastewater management, and empowerment of villagers and authorities about improved water and wastewater practices at the national and local levels.