Nikita Tananaev, Efremova V.A., Gavrilyeva Tuyara, Parfenova Olga

Spring floods in Sakha (Yakutia) Republic, Siberian Russia, annually induce a significant damage to the population and infrastructure of communities of this Arctic region. Most major urban settlements are protected from floods by dams and dikes, so rural areas take a heavy beat. In 2018, spring flooding severely hit numerous rural communities in the Amga River basin, central Yakutia, exposing deficient flood damage prevention and risk management practices in this Subarctic rural community. Hydrological data analysis shows that the 2018 flood had a 50-yr return period, and was caused by an ice jam in a nearby channel bend. Highest water stage is unrelated to both winter snow water equivalent or early May rainfall. The cold spells of late April and early May in Central Yakutia appear to promote ice-jam development in the middle section of the river, causing extreme water stage rise. Several river segments downstream Amga village, with shallow mid-channel sand bars with ground-fast ice during winter, impede ice movement during breakup that may lead to ice-jam formation. The Kritsky-Menkel distribution was used to evaluate a 100-yr flood water stage that was used in flood extent and depth mapping. Estimated tangible direct damage to the Amga village equals ₽5.1B, or $75.6M in 2018 prices, though the community reclaimed only ₽0.13B, or 2.5% of this total. Questionnaire survey revealed that most residents report important deterioration of drinking water quality and health after flooding.