> http://www.openstreetmap.org/?mlat=49.41176&mlon=8.68160#map=18/49.41176/8. >68160 I was swimming there today in the evening. My (highly personal) impression is, that it's not any more dirty than many lakes, where Germans tend to swim in when it starts getting hot. Stream was almost not noticable, getting in was a bit slippery due to algae.