Angirių HE vandens lygių fluktuacijų mažinimo Šušvės upės ekosistemai galimybių tyrimai

Abstract

After a 16-m high dam was constructed and a 297-ha pond was arranged in the river Šušvė nearby Angiriai in 1980, previous natural flow regime of the river has changed: 15 500 000 m3 of water accumulated above the dam are not discharged via a natural bed, but through two 1,5 × 1,5 m bottom orifices and flood discharges (up to Q1 % = 296 m3/s) are directed into the lower bay through a 16-m high shaft spillway of floods. Such arrangement of the Angiriai dam ensured it to become an essential obstacle for migrating fish. In 2000, after the arrangement and exploitation of Angiriai Hydroelectric Power Station, the water regime in the lower bay changed. The study results have shown that artificial floods induced by Angiriai Hydroelectric Power Station as well as the discharge flowing through the bottom orifices due to high velocities (13–14 m/s) and temperature differences create stressful situations for young fish in the lower bay. In the part of the river below the dam the ecological situation could be improved if a fishladder was arranged, or environment protecting discharge was discharged through a water recipient of Hydroelectric Power station that is arranged at 3 m depth below the pond surface.