GC23A-1124
Water Storage in Reservoirs Built from 1975 to 2012 Significantly Altered the Observed Runoff and Calculated Evapotranspiration Trends over China
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Yuna MAO1, Kaicun Wang1, Xiaomang Liu2 and Changming Liu3, (1)Beijing Normal University, Beijing, China, (2)IGSNRR Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing, China, (3)Key Laboratory of Water Cycle and Related Land Surfaces, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science, Beijing, China
Abstract:
Evapotranspiration (ET), calculated as the difference between observed precipitation (P) and runoff (R), has been used as a standard dataset to study the long-term variability of ET_ENREF_1_ENREF_1_ENREF_1. Reservoir construction may significantly alter the water budget by permitting more water to be stored in the land surface, resulting in a decrease in observed runoff and, in turn, an increase in calculated ET=P-R. However, this pattern has not been well quantified, particularly in China, where increasing numbers of reservoirs are being built. Here, we show that the water stored in the newly built reservoirs significantly altered the trend of calculated ET. After accounting for the surface water storage change resulting from reservoir construction, the original significant trend in ET of 5.26% per decade decreases sharply to -0.53% - +1.95% per decade for the period from 1997 to 2012, which is consistent with the negligible changes in its determining factors. From 1975 to 2012, the reservoir total storage capacity in China increased by 0.46×1012 m3, which can explain an increase of 12.3% in the calculated ET or a decrease of 19.9% in the observed R. This study indicates that the impact of reservoir construction on calculated ET trends cannot be ignored.
