Hydrochemical Characteristics and Controlling Factors of Surface Water in Upper Nujiang River, Qinghai-Tibet Plateau

Rivers play an essential role in the global matter transport and hydrogeochemical cycle. Hydrogeochemical research is significant to developing protecting water resources Qinghai-Tibet Plateau its lower reaches. This study aimed identify hydrochemical characteristics controlling factors of Daqu River Gaqu Dingqing County, two tributaries upper Nujiang River. used spatial analysis, trilinear diagram ion ratio analysis indexes investigate factors. Results show that Ca2+ Mg2+, HCO3? SO42? are main cations anions these rivers. HCO3·SO4-Mg·Ca HCO3·SO4-Ca·Mg primary types for surface Rivers, respectively. The influence atmospheric precipitation anthropogenic activities weak. carbonated water–rock reaction Ca2+, source, hot springs act as source supplements HCO3?. Mg2+ from magnesite dissolution exists basin. Weak reverse cation exchange occurs both receives more low-mineralized glacier meltwater along flow, whereas high-mineralized spring water.