การวิเคราะห์พื้นที่แห้งแล้งบริเวณพรุควนเคร็งสำหรับการจัดการไฟไหม้พรุโดยใช้เทคโนโลยีภูมิสารสนเทศ

Abstract

The objectives of research cover are (1) to study the drought of Kuan Kreng peat swamp (KKPS) area and generate drought hazard maps (DHM) using a geo-informatics technology (2) to assess the vulnerable areas of peatland fire in KKPS by analysis of drought hazard maps and environmental factors of peat fire using a geographical information system (GIS) and (3) to propose the approach of management of peatland fire in KKPS. The study of the drought of KKPS was carried out by using three factors of drought and six drought indices: Meteorological-based drought indices derived from the standardized precipitation index (SPI) and the meteorological drought Index (DI). Remote sensing-based drought indices using data based on images from satellite were used to derive further vegetation drought index including the normalized difference drought index (NDDI) and the vegetation health index (VHI). Hydrological based drought indices were studied based on the water table level (WTL) and drought assessments were also based on the standardized water level index (SWI) calculated from data on surface water and the groundwater level in the peat swamp. The study of the drought hazard areas in KKPS was determined by using the analytically hierarchy process (AHP) analysis of primary factors and secondary factors of drought. GIS was used to map the combined drought indices and apply the AHP technique to DHM identification in the study area. The vulnerable areas assessment of peatland fire is analyzed using drought hazard maps and environmental factors of peat fire by applying fuzzy analytic hierarchy process (FAHP) and GIS technique to peatland fire vulnerability (PFV). The results of the drought of KKPS are presented in the form of maps based on the SPI, DI, NDDI, VHI, WTL and SWI. The study focused on the droughts in two years: 2010 and 2012. The year 2010 was subject to the El Nino phenomenon while 2012 was not. The results of the study showed that the drought indices of the SPI, NDDI, WTL and SWI are associated with season, rainfall, land use and the peat fires occurred in the KKPS. The three factors of drought indices used, meteorological, vegetation and hydrological for the period of April to September indicate the likelihood of peatland fires in the KKPS area during that period. For the year of El Nino, the drought started from February to September. Therefore, these indices can be used efficiently for monitoring the drought that poses risk of peatland fires. In addition, a higher than 0.6 NDDI is found to be associated with peatland fires normally occurring in the peat swamps. The results of the drought hazard areas in KKPS by the AHP found that the high potential of factor for drought in peat swamp forest were hydrological based drought (WTL, SWI). The study showed that the severe drought to extreme drought occurred during June to July. It was found that drought hazard areas almost situated in boundary of Hua Sai District and Ron Phibun District, but only for the oil palm plantations, rice fields, open areas for agriculture and in the peat swamp forest including the degraded forest. The results of the vulnerable areas assessment of peatland fire by the FAHP found that the high potential of factor to risk peat swamp forest fire were drought from dry season in peatland. During periods without rain, both the surface water and the groundwater in the peat swamp run dry and there is a huge risk of forest fires. From the PFV analysis, there was only a high degree of risk in the area, most of which occurred at the edges of the peat swamp in boundary of north of the wildlife-protected areas of Bor Lor and Thale Noi in Nakhon Si Thammarat Province. Especially, only for the oil palm plantations, grass field areas and in the degraded peat swamp forest in the upland. This study has proposed the introduction of environmental management of peatland fires in KKPS areas. The use of geo-informatics technology for monitoring and prevention of peatland fire in KKPS. Especially, the SPI index provides effective assessment of the drought caused by the abnormal rain. The WTL and SWI indices can be used to monitor the drought in the peat swamp, particularly based on the available water in the swamp. The indices can assess the dryness of the peat swamp which could cause the peatland fires. The NDDI index from satellite images can be used to validate the wilting of vegetation or its lack of water. In addition, the drought hazard map and peatland fire vulnerability map can be used in the planning for sustainable management of KKPS.