Arheilger Muehlchen

Germany Lake 1 - Excellent

Arheilger Mühlchen is a small shallow reservoir pond located on the eastern edge of Arheilgen, a northern district of Darmstadt, near Kranichstein. Covering 1.1 hectares with a maximum depth of 2.97 meters, it has been operated as a public swimming facility since 1924. The pond receives water from the Ruthsenbach stream and features shallow, masonry-lined shores with adequate meadow areas for sunbathing on both sides, along with a small gravel entry point intended for children.

Reviews

No reviews yet.

Write a review

Photos

Upload a photo

Water

Shallow reservoir pond (Flachstausee) covering 1.1 hectares with a maximum depth of 2.97 meters and mean depth of 1.90 meters. Water originates from the Ruthsenbach stream. The embankment is located at the northwestern end of the pond.

Location

Located on the eastern edge of Arheilgen, a northern district of Darmstadt. Access is at the northern end of the dam via road K177 between Arheilgen and Kranichstein, or from Kranichstein railway station. The facility receives an average of 50 to 2000 daily visitors during the swimming season.

Facilities

Masonry-lined shores with entry points throughout. Adequate meadow areas for sunbathing (approximately 150–200 meters on each side). Small gravel entry area for children. Lifeguard services and water quality monitoring in place. Contact operator: Darmstädter Sportstätten GmbH & Co. KG, Tel. 06151 132974 and 132972.

Season

Official swimming season: 17 May 2026 to 13 September 2026. Monitoring occurs before the season starts and at least monthly during the season.

Water Quality

Water quality classified as Excellent. Annual classifications 2021–2025 all rated Excellent. Monitoring shows indicator bacteria (enterococci and Escherichia coli) generally within acceptable limits. Water clarity varies seasonally with visibility ranging from 0.31 to 3.0 meters. The water body exhibits eutrophic trophic status (LAWA classification: eutroph 1) with medium nutrient loading. Potential pollution sources include stormwater and combined sewer discharges. Cyanobacteria (blue-green algae) blooms have been frequently observed toward the end of the swimming season in past years.

Risks

Cyanobacteria (blue-green algae) blooms frequently occur toward the end of the swimming season with high observed frequency. Cyanobacteria can produce substances causing allergic reactions and skin irritation in swimmers. Medium future risk of cyanobacteria mass development based on trophic status. Water visibility can decrease significantly during summer months (as low as 0.31 meters). Stormwater and combined sewer discharges present potential hygiene hazards. Reduced inflow during summer months due to structural changes in the inlet system has caused water level fluctuations.