The Leningrad oil shale deposit (formerly Gdovskoye) is characterized by high watercutting, which is associated with its karst nature. The average water-yield coefficient of the four operating mines is currently about 7 m³ per 1 m of extraction, and in the pre-war years it reached 59 m³/t and more. Stable average annual inflows to individual mines range from 520 to 1,060 m³/h, and total inflows from 2,500 to 3,300 m³/h. Over the last 15 years, 384 million m³ of water has been pumped out, and the average inflow to the mines has been about 3,000 m³/h. No downward trend in total water inflow is observed.