The Aargau region’s largest national wetland is at risk due to nearby manure spreading, prompting federal calls for increased protection. Residents observed numerous tanker trucks distributing slurry close to Hallwilersee. Although legal under current regulations, environmentalists warn of detrimental effects on local ecosystems, particularly the endangered Great Meadow Butterfly, which relies on the wetland. Conservationists are urging the canton to establish necessary buffer zones to protect this vital area, citing a decades-long need for such measures. The federal government demands binding regulations by 2030.