การประเมินศักยภาพของฝ่ายชะลอน้ำในพื้นที่ป่าสักงาม โดยใช้เทคนิคภูมิสารสนเทศ

Abstract

Assessment of the potential of check dams in Pa Sak Ngam area, Luang Nuea Sub-district, Doi Saket District Chiang Mai Province using geospatial techniques, this study has three objectives: 1) to study the changes in soil moisture and forest fertility, 2) To assess the potential of the check dams in Pa Sak Ngam village, and 3) to analyze the suitable location for building check dams. Methods for studying changes in soil moisture and forest fertility used data from Landsat 4 5 7 8 satellite images for the period from January to April and November to December 1987 to 2017. In the part of assessing the potential of the check dams, changes in soil moisture and forest fertility were observed around the sample check dams. It is divided into 2 forms: Comparison between areas with check dams and without check dams and comparing between the periods before and after the check dam construction. The study of the suitable location of check dams in the Pa Sak Ngam area from check dam locations in the area was studied by physical factors, namely soil type, soil moisture content, and percentage slope according to the efficiency level of the check dams. The results showed that when studying the total area of the study area, it was found that soil moisture tended to decrease but forest fertility tended to increase. In the case study of changes in soil moisture and forest fertility along rivers, it was found that most of the sampled streams had increased soil moisture, only the Huai Lao Kham Pom, Huai Lao Khang Swan Lung Teng's and Huai Du which tends to decrease in soil moisture, but the fertility of forest tends to increase in every stream. From the assessment of the potential of check dams by comparing areas with and without check dams, it was found that out of the 30 sample weirs, there were 7 high efficiency check dams, 12 medium efficiency check dams and 11 low efficiency check dams. Comparing the time before and after the check dam construction, it was found that 30 sample check dams did not have high efficiency check dams. There were 11 weirs of moderate efficiency and 14 weirs of low efficiency and could not identify the efficiency of 5 weirs. From the study of the suitable location of check dams in Pa sak Ngam area from check dam locations, it was found that high-efficiency check dams had complex slope soil types, soil moisture was in the range of 10.288-25.017 and the slope percentage was in the range of 6.763 - 21.667. Check dams with moderate efficiency have complex slopes and clay soils, soil moisture was in the range of 20.078-24.533 and the slope percentage was in the range of 7.788 - 42.496. And check dams with low efficiency was complex slope. Soil moisture was in the range of 18.510-20.053 and the slope percentage was in the range of 18.078 - 19.254. Testing the sample check dams according to the efficiency of each type of check dam, it was found that the check dams used for testing at each level of efficiency were consistent with the check dams used in the analysis.