Dam site engineering geophysics in Yugoslavia

Several long rivers run through the territory of Yugoslavia, and each one of them is unique. The Danube is the largest, passing through the narrow canyon known as the Djerdap where the largest dam in Europe, with a power-generating capacity of 1200MW, has been constructed. The enormous flow of water, up to 15000 m3 s-1, no longer goes unexploited. A second large dam on the Danube is to be completed soon. The Sava River, more than 940 km long, flows through Yugoslavia from its source in the Alps to Belgrade, where it discharges up to 6000 m3 s-1 into the Danube. The Sava forms the northern geographical boundary of the Balkan peninsuia. North of the Sava River is the Drava River: there are at least 15 small dams across these two rivers, and more are bound to be built. The most crooked river in Europe is the Drina. lts source is at an elevation of 1220 m, and it flows through fascinating gorges and canyons with spectacular lakes of crystal clear water, before discharging its flow of 500 m3 s-1 into the Sava River. Other notable dams are the Mratinje, on the Piva River, which is more than 220 m high, and a unique one on the Trebišnjica River which retains a storage reservoir on and within karstified limestone, with a substantial fraction of the accumulated water lying inside the porous limestone. Geophysicists are among the first experts to be called in for dam-site feasibility studies, which must be directed towards the foundation of the dam and also the leakage of water from the reservoir which would accumulate behind it. The problems are numerous, and some interesting case histories from Yugoslavia are presented.