A comparative performance analysis of three standardized climatic drought indices in the Chi River basin, Thailand

AbstractDrought indices are generally used as a tool for monitoring changes in drought conditions. This paper evaluated the performance of three climatic drought indices to characterize drought trends in the Chi River basin in Northeast Thailand. Initially, the drought assessment was conducted using the Standardized Precipitation Index (SPI), a precipitation-based index, and the Standardized Precipitation Evapotranspiration Index (SPEI), an index taking into account the difference between precipitation and potential evapotranspiration (PET). Then, this study simply applied an index called the Standardized Precipitation Actual Evapotranspiration Index (SPAEI), similar to the commonly used SPEI, with the difference being in the use of actual evapotranspiration (AET) instead of PET. Time series of the three indices were compared with observed droughts. The results indicated that various indicators of different indices can have diverse effects on drought conditions. The simple SPI, considering only precipitation, can be used to identify characteristics of droughts with certain restrictions. Being multivariate indices, the SPEI and the SPAEI were able to clearly detect the temporal variability of droughts to a greater extent than the SPI index. Moreover, the different results derived from using P-AET instead of P-PET made a substantial difference to temporal drought severity. Thus, climatic water demand had important aspects in determining the drought conditions for this area

Root Zone Soil Moisture Assessment at the Farm Scale Using Remote Sensing and Water Balance Models

Water resource planning and management necessitates understanding soil moisture changes with depth in the root zone at the farm scale. For measuring soil moisture, remote sensing methods have been relatively successful. Soil moisture is estimated from image data, using in situ moisture and an empirical scattering model via regression fit analysis. However, in situ sensor data are prone to misinterpretations, requiring verification. Herein, we aimed at investigating the application of soil moisture from the water balance model towards verification of in situ soil moisture sensor data before in situ data was assessed for its relationship with remote sensing data. In situ soil moisture sensor data was obtained at 10 and 30 cm, and CROPWAT8.0 furnished root zone soil moisture data. The correlation between the in situ soil moisture at 10 and 30 cm was 0.78; the correlation between the soil moisture from CROPWAT8.0 and the in situ soil moisture were 0.64 and 0.62 at 10 and 30 cm, respectively. The R2 between Sentinel-1 backscatter coefficients and in situ moisture were 0.74 and 0.68 at each depth, respectively. Therefore, the water balance model could verify sensor results before assessing in situ soil moisture data for relationship with remote sensing data

Root Zone Soil Moisture Assessment at the Farm Scale Using Remote Sensing and Water Balance Models

Water resource planning and management necessitates understanding soil moisture changes with depth in the root zone at the farm scale. For measuring soil moisture, remote sensing methods have been relatively successful. Soil moisture is estimated from image data, using in situ moisture and an empirical scattering model via regression fit analysis. However, in situ sensor data are prone to misinterpretations, requiring verification. Herein, we aimed at investigating the application of soil moisture from the water balance model towards verification of in situ soil moisture sensor data before in situ data was assessed for its relationship with remote sensing data. In situ soil moisture sensor data was obtained at 10 and 30 cm, and CROPWAT8.0 furnished root zone soil moisture data. The correlation between the in situ soil moisture at 10 and 30 cm was 0.78; the correlation between the soil moisture from CROPWAT8.0 and the in situ soil moisture were 0.64 and 0.62 at 10 and 30 cm, respectively. The R2 between Sentinel-1 backscatter coefficients and in situ moisture were 0.74 and 0.68 at each depth, respectively. Therefore, the water balance model could verify sensor results before assessing in situ soil moisture data for relationship with remote sensing data

Willingness to Pay for Sponge City Project Initiatives in Bangkok

Urban flooding crisis in Bangkok plays an important role in the lives of people. Sponge City is a concept to alleviate the problem. The paper aims to estimate the willingness to pay of people in Bangkok to initiate a Sponge City project. According to a study of 300 respondents by the Contingent Valuation Method (CVM). The results show that the average of willingness to pay for Sponge city per person is 145 – 158 baht. Furthermore, the factors that contributed to the willingness to pay for the project were the initial bid and the opinion on the future flooding problem. The results indicate that the socio-economic characteristics including anxiety is important in carrying out activities for people to participate. Therefore, to enhance people participation in the Sponge city, the project should start during the period of economic expansion or launch in the areas with high demand or good economic zones. As well, policy makers should promote the project through various channels and should promote to make people aware of the problem.---ปัญหาน้าท่วมในกรุงเทพมหานครมีบทบาทสาคัญในการดาเนินชีวิตของคนในสังคม การก่อสร้างเมืองฟองน้าจึงเป็นแนวคิดเพื่อบรรเทาผลกระทบที่อาจจะเกิดได้ ซึ่งประชาชนในพื้นที่จะมีส่วนในการได้รับประโยชน์โดยตรง บทความนี้มีวัตถุประสงค์เพื่อวิเคราะห์การรับรู้และความเต็มใจจ่ายของประชาชนในกรุงเทพมหานครต่อการริเริ่มโครงการเมืองฟองน้า โดยผลการศึกษาจากกลุ่มตัวอย่าง 300 ราย ด้วยวิธีสมมติเหตุการณ์ให้ประเมินค่า (Contingent Valuation Method: CVM) พบว่าค่าเฉลี่ยของความเต็มใจที่จะจ่ายเงินบริจาคในการดาเนินโครงการเมืองฟองน้าต่อรายอยู่ที่ 145 – 158 บาท โดยปัจจัยที่ส่งผลต่อความเต็มใจจ่ายเพื่อให้เกิดโครงการ คือ ราคาที่นาเสนอเริ่มต้น และความกังวลต่อเหตุการณ์น้าท่วมในอนาคต ผลการวิจัยชี้ให้เห็นว่าลักษณะทางเศรษฐกิจและสังคม รวมถึงความวิตกกังวลมีความสาคัญในการดาเนินกิจกรรม เพื่อให้ประชาชนมีส่วนร่วม ภาครัฐหรือหน่วยงานที่เกี่ยวข้องควรเริ่มจากการวางแนวนโยบายในการทาโครงการในช่วงที่มีการขยายตัวทางด้านเศรษฐกิจ หรือเริ่มต้นในพื้นที่ที่มีลักษณะของเศรษฐกิจที่ดี ตลอดจนการประชาสัมพันธ์โครงการผ่านช่องทางต่างๆ ควรให้มีการแทรกเนื้อหาในเชิงผลกระทบที่สาคัญ เพื่อให้ประชาชนเกิดความตระหนักต่อปัญหา อันจะส่งผลต่อความเชื่อมั่นในโครงการที่จะเกิดขึ้นในอนาค

Hydropower development priority using MCDM method

Hydropower is recognized as a renewable and clean energy sources and its potential should be realized in an environmentally sustainable and socially equitable manner. Traditionally, the decision criteria when analyzing hydropower projects, have been mostly a technical and economical analysis which focused on the production of electricity. However, environmental awareness and sensitivity to locally affected people should also be considered. Multi-criteria decision analysis has been applied to study the potential to develop hydropower projects with electric power greater than 100kW in the Ping River Basin, Thailand, and to determine the advantages and disadvantages of the projects in five main criteria: electricity generation, engineering and economics, socio-economics, environment, and stakeholder involvement. There are 64 potential sites in the study area. Criteria weights have been discussed and assigned by expert groups for each main criteria and subcriteria. As a consequence of weight assignment, the environmental aspect is the most important aspect in the view of the experts. Two scenarios using expert weight and fair weight have been studied to determine the priority for development of each project. This study has been done to assist policy making for hydropower development in the Ping River Basin.Multi-criteria Hydropower Renewable energy

The effect of reforestation on stream flow in Upper Nan river basin using Soil and Water Assessment Tool (SWAT) model

Forests are an important natural resource, vital to all life. Forests are an important source of food, clothing, and medicines, as well as a place to live. Water released from forests drains into the soil causing groundwater to emerge as stream flow throughout the year. In Thailand, most forests have been encroached by logging, paper production, and housing construction. Population growth and the need for farming area for crop and livestock production have also caused forest encroachment. Technical tools are needed to support the decision makers and planners if they are to achieve objectives of water conservation, and development. These technical tools are needed for assistance in the engineering, socio-economic, and environmental planning. The Soil and Water Assessment Tool (SWAT) was used in the hydrological modeling in this study of the complex and dynamic problems of The Upper Nan river basin. This was a case study to evaluate the impact of changing conditions in the river basin affected by the stream flow due to reforestation. The watershed area was delineated into 5 sub-watersheds based on surface topography provided by the Digital Elevation Model (DEM) and the parameters of each of these watersheds were calculated. The land use data was processed and reclassified to match with the SWAT model land use code. Ten different categories of land use in the study area were used for SWAT processing. Types of land use consist of: mixed forest (33. 7%), disturbed forest (30. 2%), evergreen forest(17. 7%), paddy field(7. 1%), orchard(3. 7%), range brush(2. 7 %), field crop(1. 7%), planted forest (1. 7%), urban (1. 4%) and water resources (0. 4%) . Twenty-two types of soil were found in the basin. The initial curve number values were assigned based on the land use type and soil hydrologic group for the average antecedent moisture condition of the curve number method. The potential evapotranspiration was computed using the Penman-Monteith method. The simulation was performed using three reforestation scenarios to assess stream flow:(1) improved disturbed forest, (2) field crops and range grass, and (3) both disturbed forest and field crops. The results of reforestation from scenarios 1 and 3 can increase stream flow in the drought season and can also reduce the flow in the wet season in the main stream and its tributaries. For scenario 2 Reforestation had no significant effect on the main stream

The Impact of Para Rubber Expansion on Streamflow and Other Water Balance Components of the Nam Loei River Basin, Thailand

At present, Para rubber is an economical crop which provides a high priced product and is in demand by global markets. Consequently, the government of Thailand is promoting the expansion of Para rubber plantations throughout the country. Traditionally, Para rubber was planted and grown only in the southern areas of the country. However, due to the Government’s support and promotion as well as economic reasons, the expansion of Para rubber plantations in the northeast has increased rapidly. This support has occurred without accounting for suitable cultivation of Para rubber conditions, particularly in areas with steep slopes and other factors which have significant impacts on hydrology and water quality. This study presents the impacts of Para rubber expansion by applying the Soil and Water Assessment Tool (SWAT) hydrological model on the hydrology and water balance of the Nam Loei River Basin, Loei Province. The results showed that the displacement of original local field crops and disturbed forest land by Para rubber production resulted in an overall increase of evapotranspiration (ET) of roughly 3%. The major factors are the rubber canopy and precipitation. Moreover, the water balance results showed an annual reduction of about 3% in the basin average water yield, especially during the dry season