PRELIMINARY DESIGN OF WATER REGIME AND VRBAS RIVER REGULATION THROUGHOUT BANJA LUKA CITY URBAN AREA   By development of “Flood Hazard Maps and Flood Risk Maps for the Vrbas river basin in BiH”, flood causes and volume of flooding have been defined by calculated flood waters of Vrbas in the area of Banja Luka city. According to this planning and strategic document, flood risk from Vrbas river on the area of Banja Luka city was estimated as high and extremely high for the biggest part of t...