Extreme drought pushes Slapy reservoir down to winter level

The Slapy reservoir on the Vltava River has dropped to its winter level far earlier than usual due to an extreme hydrological drought. The news was reported by Povodí Vltavy, the state company that manages the reservoir system along the river.

The chain of events began on September 4, when falling water levels forced the Orlík reservoir to reduce its outflow. To maintain the required flow of the Vltava through Prague, the company had to tap into Slapy's reserve water supply for the first time in its history. Until then, the water level at Slapy had held steady at 269.3 metres above sea level.

By 8:00 PM on Saturday, the level had fallen to 267.65 metres, and by 7:30 PM today it had already dropped to 267.47 metres — below the winter mark.

Why a winter level matters

The winter water level is deliberately kept lower to leave free capacity in the reservoir in case of potential floods caused by spring snowmelt. This year, however, the reservoir reached that mark far earlier than usual — purely because of the drought.

Thanks to the increased outflow from Slapy, the lower Vltava is still receiving the required 40 cubic metres of water per second. Without regulation along the Vltava cascade, the flow through Prague would currently amount to only about 10–15 cubic metres per second, despite today's somewhat rainier weather.

The rate at which the water level falls depends directly on the difference between inflow and outflow. Since the minimum outflow from the Vltava cascade is more than double the current inflow, the water level continues to drop.

Source: novinky.cz