Improvement of the theory of shaft spillway calculations Alim Gur’yev, Nartmir Khanov, Marina Chumicheva, Aleksandra Verkhoglyadova, Buchra Hayek and Abderrezak Brakeni E3S Web Conf., 264 (2021) 03031 Published online: 02 June 2021 DOI: 10.1051/e3sconf/202126403031