Drought Risk Assessment based on PDSI in the Daqinghe Watershed, North China Shaohua Liu, Huiyong Huang, Gang Hu, Hui Wan, Yongyan Wu, Yibo Yan and Sidong Zeng MATEC Web Conf., 246 (2018) 02043 Published online: 07 December 2018 DOI: 10.1051/matecconf/201824602043