Previous studies

In the flood season (July to September), there is sporadic runoff generated from the mountainous area beside the plain. This water, which is ungauged, enters the plain as mountain torrents or springs. The springs can be considered as being a constant flow while the mountain torrents vary from year to year. A prior field study was performed in 1999 by Akesu Water Resources Reconnaissance and Survey Team (AWRRST, 2000) to investigate the ungauged runoff. A total of 32 mountain torrents and spring ravines that lead into the plain were surveyed. The locations of these torrents and spring ravines are shown in Fig. 2. The spring ravines to the north of the Tuoshigan River originate from mountainous area outside the study area. This means that these springs can be regarded as runoff generation. But the springs that flow to the Kumalake River are generated from plain area inside the study area, and geological analysis shows that part of the springs are formed from confined water originated from the Kumalake River (RDI, 1989). Therefore, these springs can be regarded as transformation of river water. It is worth mentioning that the investigation was performed only in a single year, 1999. Data for other years are unavailable. Because the spring flow is relatively steady, the surveyed spring flow data is extended to other years. The surveyed mountain torrents flow is also directly used in un-surveyed years even though these data are more uncertain. [2]AWRRSTAkesu Water Resources Reconnaissance and Survey Team [3]RDIReconnaissance and Design Institute of Xinjiang Production and Construction Corps