The main subject of this work is the life cycle, or the phase through which each project passes. The project is a time-bound enterprise designed to create a unique product or service. The project has three basic mutually conditioned elements: task, resource, time. The purpose of the project is to produce the desired change - in people's behavior, in the way the system works or in the way the institution works. It is characteristic for a project that addresses the problem or the needs of a specific group using new ideas and techniques, building on existing capabilities and potentials. Hydroelectric power plant Zakučac or HPP Zakučac is a derivative hydro power plant built in the downstream river Cetina, near Omis (Splitsko-dalmatinska County), two kilometers from the mouth of the river Omis upstream. The largest plant on the Cetina river basin is the largest hydropower plant in Croatia, according to installed power and possible electricity generation. Electricity production in the HE Zakučac is of vital interest for the stability of the power system in Croatia, which is an essential permanent availability of the hydro power plant. The main objective of the reconstruction project of HE Zakučac is to complete the reconstruction and furnishing of the existing facility in order to renovate the facility that will produce electricity in the future as long as possible. The increase of the installed flow or installed power of the Zakučac hydro power plant will have a positive economic and environmental aspect, and will positively affect the biological minimum of Cetina, especially in the summer months.