World Fish Migration Day 2022
Ogosta River is one of the main right bulgarian tributaries of Danube River. In order of exploitation its water resources, the river accumulates multiple anthropogenic pressure like hydrological and morphological alterations including: modified riverbed, straightened watercourse, concreted riverbanks, detached floodplains, water flow regulation as well as disrupted river continuity, due to numerous river obstacles like: large and small dams, weirs and sluices. At the foothill zone between the Balkan Range and the Danube Valley was built one of the largest Reservoirs in Bulgaria – “Ogosta”, with full capacity of 506 million cubic meters. The Dam was built for irrigation purposes but nowadays also produce hydropower energy. Downstream the reservoir the river section experience hydropeaking events, due to hydropower production, as well as thermal modification, due to cold water release. Several Small Hydro Power plants was built downstream Ogosta Reservoir, all of them “Run of the River”, mostly with inefficient fish-passes, impairing fish migration. Most of the described river obstacles are hot-spots for angling and especially poaching activity, due to it function as a bottleneck during the fish migration.
The current event intend to briefly describe the main river obstacles for fish migration in Ogosta River, downstream Ogosta Reservoir. Monitoring of key river obstacles as well as data about few environmental parameters also will be collected.
Roadtrip: Ogosta Dam (43.396500 23.222467) – Sofronievo weir (43.648379 23.785930) – Hayredin HPP (43.610568 23.684742) – Montana city (optional).
Online Event - No
Country - Bulgaria
Name of contact person - Stefan Kazakov