Monitoring And Analyzing For Overflowing Status Of Hotan River In Summer Season By Remote Sensing

By using visual interpretation combined with supervised classification in ENVI 4.5 and with the functions of localization, measurement, and layer overlay of ArcGIS 9.2, the summer season overflowing status in middle and lower reaches of Hotan River had been monitored and analyzed, the results of which shows that: (1)The overflowing status in middle and lower reaches of Hotan River is fairly serious, at the same time, overflowing status of irrigation areas in oasis area has drawn much attention too. The maximum overflowing area in study region is above 455 km~2. (2) compared with other reaches the amount of overflowing water of oasis edge in the middle reach is less, the area of which is below 35 km~2 in monitoring date with the percentage of 95%, and the overflowing trace is unavailable in 35% of the monitoring date; From Keshen Mishen on where 2 rivers join together to the crossroad of old river channel and Hotan River, the overflowing areas are all over 35 km~2 in 45% of the monitoring date except 5 August 2004 and 29 July 2008 with the monitoring area being 0; The overflowing status of the reach from the crossroad of the old river channel to Xiaota Hydrometric Station is heaviest, most of which is over 70km~2 with the maximum of 70km~2. (3) On the whole basin 11 overflowing sites have been observed, among which 4 distribute on the left and 5 distribute right sides of the head reach areas of Hotan River respectively, coupling with a new floodplain on each side, and also an overflowing site on the left of Kalakash River has been observed. It can also be found that, on the whole, the overflowing sites mainly distribute on the head reach of Hotan River. 9 undetermined inputting cuts were found on two branches of Hotan River of which, 4 in Kalakash River, 5 located in Yulongkash River. (4) It can be found that overflowing status of Hotan River could be heavily influenced by amount of precipitation from the regression analysis of average temperature and rainfall with overflowing area from 6 different meteorological stations. (5) A big overflowing process with the overflowing area from 22.3 km~2 on 1st Aug. to 213.6 km~2 on 17th Aug. and overflowing depth of 104.9km was monitored to the old river channel which caused deadly paroxysmal flood hazard to 5 companies of Group 5, Division 1, and the reasons of which were ascribed to higher air temperature and heavier precipitation.