The area of Eastern Herzegovina is one of the most karstified regions in the world. Deep karst, sinking rivers, underground flows, temporary flooded karst poljes and lack of arable land is main natural property of the region. Due to two kinds of misfortune, flood and drought, people have emigrated from this region searching for a better life. The book contains new scientific data and engineering experience collected during more than 100 years of investigations and construction. To provide optimum water management and economic development, thousands of new data are collected and presented in the book. Necessity for balance between regional development and preservation of nature was one of the important request.