Discharge Estimation for an Ungauged Inland River in an Arid Area Related to Anthropogenic Activities: A Case Study of Heihe River Basin, Northwestern China

In the arid areas, the discharge in some reaches is unsurveyed, which makes related works trapped. It is important to estimate a long-term discharge in an ungauged river using available fragmentary data including those on human activities. In this work, the authors proposed a procedure of monthly discharge estimation for an ungauged inland river based on spatiotemporally discontinuous information, such as water diversion for irrigation, water allocation planning, and statistical relations of discharge at different locations. A typical ungauged river reach of Heihe River in northwestern China was selected as a case study. Monthly discharge from 1991 to 2007 at one gauged section was estimated using this procedure to validate the procedure, and the results show its potential in estimating discharge for an ungauged area. Monthly discharge from 1979 to 2014 at four unmonitored sections was estimated using the same procedure, and the trend analysis was conducted to check the facticity of the estimated discharge. The annual and monthly trends could well describe the effects of anthropogenic activities on the flow at different sections. In general, the method is feasible to provide support pertaining to water management or eco-hydrological researches and could be easily extended to other similar places.