Harz Region: Reservoir Levels Rebound After Heavy Rain and Snowmelt
West Harz reservoirs rebound after heavy rain eases water crisis
After weeks of above-average precipitation at the end of winter, combined with increased inflow from early snowmelt, water levels in the West Harz drinking water reservoirs have seen a noticeable recovery. Currently, the reservoirs are around 68 percent full, compared to a long-term average of 83 percent, according to a press release from Harzwasserwerke GmbH.
"The developments of recent weeks have significantly improved the situation at the reservoirs," said Hendrik Rösch, Technical Managing Director of Harzwasserwerke. "Although reservoir levels remain below average, drinking water supply remains secure."
Rain and Snowmelt Ease Pressure on Water Supply
As early as late February, rising rainfall in the Harz region began to relieve pressure on the reservoirs. Combined with snowmelt, the past weeks have seen substantially higher inflows, leading to increased water levels across all six West Harz reservoirs.
Previously, the reservoirs had been well below average due to an extremely dry spring in 2025 and a subsequent dry winter. The recovery is particularly evident at the Ecker and Söse reservoirs, which now stand at around 82 percent and 72 percent capacity, respectively. The Oker Reservoir has also rebounded, rising from roughly 33 percent in February to about 45 percent.
Interconnected System Safeguards Drinking Water
A key factor in ensuring supply security is the Harzwasserwerke's interconnected reservoir network. The Oker and Innerste reservoirs are linked to the Granetalsperre, allowing water transfers to support drinking water production when needed.
With a current fill level of around 60 percent, the Granetalsperreâthe largest drinking water reservoir in the systemâholds sufficient reserves for the upcoming summer months.
Groundwater Responds with a Delay
While reservoir levels have improved in the short term, rainfall and dry spells typically affect groundwater aquifers only after a time lag.
Impacts on groundwater recharge, water table levels, and extraction rates usually become apparent over a longer period. Many groundwater monitoring stations still reflect the influence of the wetter years of 2023 and 2024.
