The effective management of water resources is of great importance as it ensures the supply of water resources that may support changing water requirements over a selected planning horizon, in a sustainable and cost-effective way. Essentially, the purpose of the water resources planning process is to balance the available water resources in a system with the water requirements and losses to which the system is subjected. This paper covers a review of generic planning processes and procedures as these apply to complex hydrological systems. Its aim was to improve the balance between water supply and projected requirements which could consists of water demand management options and/or infrastructure developments. It was concluded that application of reservoir planning is of great importance, in the fact that the planning processes and procedures described in the manuscript are generic, as it would be impossible to deal with all the intricacies of complex water resources systems. Thus it is concluded that Water Resources Yield Model has an advantage over other models by managing model runs, developing a representative system network, modeling incremental sub-catchments, creating a variety of standard system features, special modeling features, and run result output options.