The Water Quality and Change Tendency Analysis for Hanjiang River Trunk Stream

This paper presents the present status and change tendency for trunk stream of Hanjiang River. The monitoring data shows that water quality of the River in general is quite good and meets the class II and III of National Surface Water Criteria. The water quality in upper reaches of Baijiawan Section, Xiangfan is evidently better than that in lower reaches. Relative poorer water quality sections are mainly located within cities and towns, and with total phosphorus as major pollutant. The water quality in different water seasons changed as mean season better than wet season and wet season better than dry season. 16 years' data shows that 37.5% and 25% sections for annual average value of permanganate and ammonia nitrogen is increasing.