SEISMIC EXPLORATIONS FOR DEFINING THE DAMAGE TO THE EARTH DAM PISHICA IN THE REPUBLIC OF NORTH MACEDONIA

Abstract

The reservoir was built in the middle of the 20th century with a total capacity of 750,000 m3. The height of the dam from the river terrace is 22 m, the length of the crown is 319 m, and the width of the crown is 6 m. Due to the low resistance of the earth dam and the increase of water level due to heavy rains, the lake has leaked on several occasions, causing floods and environmental disaster in the surrounding settlements. Due to heavy rains and overflow through the dam crown, damage to the downstream slope of the dam has occurred and the overall stability of the dam has been compromised. By controlled discharge of the reservoir it is brought to a stable state and the dam breakage is prevented. At the beginning of 2013, the outflow valves of the dam were opened as a result of heavy rains, with reservoir water flowing to more places and residents of the village and livestock evacuated. At the crown of the dam where there was the largest outflow of water, a gap of about 20 m wide and 3.5-4 m thick appeared. Geophysical - seismic surveys have been conducted to determine dam damage.