Multivariate statistical techniques such as cluster analysis (CA), principal component analysis (PCA), factor analysis (FA), and discriminant analysis (DA) were applied for the assessment of spatial and temporal variations of a large complex water quality data set of the Nampong River and Songkhram River, generated for more than 10 years (1996-2012) by monitoring of 16 parameters at different sites. According to the water quality characteristics, hierarchical CA grouped 13 sampling sites of the Nampong River into two clusters, i.e., upper stream (US) and lower stream (LS) sites, and five sampling sites of the Songkhram River into three clusters, i.e., upper stream (US), middle stream (MS) and lower stream (LS) sites. PCA/FA applied to the data sets thus obtained five latent factors explaining 69.80 and 69.32 % of the total variance in water quality data sets of LS and US areas, respectively, in the Nampong River and six latent factors explaining 80.80, 73.95, and 73.78 % of the total variance in water quality data sets of LS, MS, and US areas, respectively, in the Songkhram River. This study highlights the usefulness of multivariate statistical assessment of complex databases in the identification of pollution sources to better comprehend the spatial and temporal variations for effective river water quality management.

Environmetric techniques such as cluster analysis (CA), principal component analysis (PCA), factor analysis (FA) and discriminant analysis were applied for the assessment of spatial and temporal variations of a large complex water-quality data set of the Songkhram River Basin, generated during 15 years (1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)) by monitoring of 17 parameters at 5 different sites. Hierarchical CA grouped five sampling sites into three clusters, i.e. upper stream (US), middle stream (MS) and lower stream (LS) sites, based on water-quality characteristics. FA/PCA applied to the data sets thus obtained resulted in six latent factors explaining 80.80, 73.95 and 73.78% of the total variance in water-quality data sets of LS, MS and US areas, respectively. This study highlights the usefulness of multivariate statistical assessment of complex databases in the identification of pollution sources and to better comprehend the spatial and temporal variations for effective river water-quality management.

A study was conducted to assess the ecosystem health of Lower Songkhram wetland in Thailand, using a newly developed wetland ecosystem health index (WEHI) based on analysis of field survey and secondary data of the most dominant physical, environmental and socio-economic factors extracted by principal components analysis (PCA). The most influential physical, environmental and socio-economic factors identified were rainfall and awareness and participation of the local community, which had positive effects, whereas soil electrical conductivity (EC), biochemical oxygen demand (BOD) and urban development had negative effects. Based on the results, 9 of the 40 land units of the study area were in very good or good health, 11 in reasonable health, while 20 were found to be in poor or even very poor condition. These findings will be useful for decision-makers in planning and executing an effective and holistic strategy to prevent further wetland degradation.

The aim is an assessment of the actual evapotranspiration of plants by using climate data in Nakhon Ratchasima with the R in the hydrological modeling function of Abtew and Morton CRAE formulation. There are using meteorological data from 2012 - 2016 at Nakhon Ratchasima station. The case analysis shows the results of evapotranspiration are the potential of evaporation of plants each year. Abtew analysis gave higher monthly evapotranspiration results during the dry season than Morton CRAE, but with Abtew formulation gave lower monthly evapotranspiration results during the rainy season than that of the method. The results are 2 ways to use evapotranspiration for water management, which is to analyze the amount of evapotranspiration for use in irrigation systems in order to water for plants should use the form of Abtew form because it can be seen that during the dry season and the plant has a high evapotranspiration value. Form Morton CRAE should be used to assess the potential water use of plants that can be seen in the dry season, the evaporation of plants is also less because in the surrounding environment there isn’t water and has little moisture causing plants to use less water.