Ecology & Safety ISSN 1314-7234, Volume 9, 2015 Journal of International Scientific Publications www.scientific-publications.net MANAGEMENT AND DEVELOPMENT OF WATER RESOURCE SYSTEMS Donka Shopova, Igor Niagolov National Institute of Hydrology and Meteorology Bulv. Tzarigradsko shosse 66, Sofia 1784, Bulgaria Abstract This paper explores the performance of the water resource systems located in the Tundja River basin, Bulgaria. It includes multiple water intakes and two large reservoirs with complex purpose. The reservoir cascade “Koprinka” -“Jrebchevo” is used to regulate the water in the basin of the Tundja River and contribute to the increasing complexity of water allocation and implementation of rational use of water resources. The goal of this paper is to test the impact of various transferred water amounts to the Stara Zagora irrigation fields on the satisfaction of water consumers with irrigation water from the reservoir “Jrebchevo”. Summarized research of the influence of water amounts supplied through HPP “Stara Zagora” on irrigation from reservoir “Jrebchevo”. Key words: complex water resource systems, water resource management, decision support system 1. INTRODUCTION Water resource systems (WRS) are the tool through which the river runoff has been used and managed. They consist of one or more reservoirs as water sources and many hydraulic structures such as dams, canals, tunnels, irrigation systems (IRS), hydropower plants (HPP), water supply systems, etc. Their water resources are used to satisfy multiple objectives – irrigation water demand, industrial demand, drinking and municipal water demand, hydropower production, low flow augmentation, recreation, fishery demand, and provision of minimum river flow needed for ecosystems. So a great number of these objectives – natural, engineering, social, ecological, etc. – have stochastic nature like river runoff. Others are not commensurable, often not quantifiable and some have conflicting demands to the water use. WRS are complex systems with stochastic and dynamic character and include a great number of mutually joined and interacted elements. The main difficulty in the process of WRS operation and planning is to obtain determinate rules for their management because some water demands and river runoff are random variables. This makes the mathematical description and modeling a difficult task which can be solved by the successfully application of probability theory and statistics, mathematical programming, simulation technique and multiple- objective optimization. The management of water resource systems (WRS) represents a key element in achieving the balance between social-economic and ecological objectives of water usage. This study is connected with the WFD implementation and the results are obtained from water resource balances (WRB) for a real WRS in Bulgaria with the use of multiple-objective optimization and simulation technique. These two methods are applied to the water resource system located in the Tundja River basin in the scope of the whole river basin. 2. BRIEF DESCRIPTION OF THE FEATURES AND CHARACTERISTICS CONCERNING THE TASK One of the most important WRS in Bulgaria was built in the basin of the river Tundja. It includes multiple water intakes and two large reservoirs with complex purpose. The reservoir cascade “Koprinka” -“Jrebchevo” (fig.1) is used to regulate the water in the basin of the Tundja River and contribute to the increasing complexity of water allocation and implementation of rational use of water resources. The management of reservoir “Jrebchevo” is related to the management of the reservoir Page 404