Abstract
The article is devoted to of the multilevel probabilistic modeling problem for hydraulic conditions of pipeline systems (PSL) having a hybrid topology. The essence of the multilevel approach is to decompose of the design topology into a multi-loop part and tree-shaped branches by applying calculation techniques appropriate for each of the parts. A numerical study of the proposed approach was carried out on a example, which showed that to calculate all parameters except for the nodal pressure dispersions, it is sufficient to use the methods previously developed by the authors. To calculate the nodal pressure dispersions, it is necessary to take into account the correlation of the pressure field of the multi-loop and tree-like levels of the design scheme.