02590nam a2200253   450000500170000000800410001703500150005810000280007324500380010126000520013930000100019149000220020150001630022350200580038652014830044465000430192765000330197070000420200370000480204570000450209371000790213881000540221785600650227120260818212834.0070198         th                  eng    a.b105739261 aAkhtar, Muhammad Ashraf10aRiver siltation due to tin mining  aBangkok :bAsian Institute of Technology,c1975  a93 p.1 aThesis ;vno. 733  aA thesis submitted in partial fulfillment of the requirements for the Degree of Master of Engineering at the Asian Institute of Technology, Bangkok, Thailand.  aThesis (M.Eng.) - Asian Institute of Technology, 1975  aThe primary purpose of this research was to investigate and  evaluate tin mining activities as a source of sediments in the rivers which were causing a severe siltation problem in the Ranong estuary of Thailand. The study was conducted on the three rivers, draining from tin mining areas and were responsible for transporting a huge quantity of sediments into the estuary. As there were no gaging stations on the rivers before the present study, a tank model was calibrated and developed to simulate long  term run-off in one of the rivers using-nine-year daily rainfall as  input. Unit hydrograph of Thailand was, then, used to find the long term runoff in the other two rivers in order to develop flow duration curves. Functional relationships between water discharge and sediment load were developed to determine sediment rating curves. From the flow-duration and sediment rating curves of the rivers, it was estimated that about 1.7 million tons of sediments were being transported and silted in the estuary and river mouths every year. In this quantity, tin mining areas contributed about 99 percent of the sediments and only 1 percent sediments were from the forest land. Predicted sediment load and sediment dredging data for the silting reach were compared to estimate distribution of sediments in the estuary. It was found that about 34 percent of sediments were being deposited in the silting reaches at the river mouths and remaining 66 percent passed to the estuary. 0aTin mines and miningxThailandxRanong 0aSedimentation and deposition0 aSuphat Vongvisessomjai, eChairperson1 aNishimura, Hitoshi, eExamination Committee0 aPrida Thimakorn, eExamination Committee2 aBritish Government and Habour  Department of Thailand, eScholarship Donor2 aAsian Institute of Technology.tThesis ;vno. 733  3Full-Textuhttp://203.159.5.9/ait-thesis/detail.php?q=B23987