D10: Impact of Contaminants - Hydromod

Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas
EUROLAKES
D10: Impact of Contaminants
FP5_Contract No.: EVK1-CT1999-00004
Version: 4.0
Date: 25/07/01
File: D10-vers.4.0.doc
Page 70 of 136
flowing waters to protect the aquatic communities. Because of its high volume the pesticide
load from the Seefelder Aach cause no risk for the lake but the catchment of this
flowing water is only a small part of 2.4 % of the whole catchment area of the Bodensee.
In comparison of the 17 feeders of Lake Constance in Schussen, Mühlbach Randolfzell
and Mühlbach Friedrichshafen increased concentrations are found. Even higher concentrations
are found in the Kasernengraben and can be named as “heavy contaminated”.
The survey of [HETZENAUER 1997] shows, that even small feeders often are
contaminated with higher concentrations. This small feeders are not so important for
the overall loads flowing into Lake Constance. But higher concentrations could be local
harmful to the nearshore in the estuary. (For the limnological condition of Lake Constance
this area play an important part. For this reason it is necessary to reduce also
the contamination of the small feeders to a tolerable level.
In the survey of SCHLICHTIG et al 2001 a total diuron load of 40 % have been detected
in the Seefelder Aach. This cannot be the result of the agricultural diuron use and
causes the research need in non-agricultural areas.
10.2 CATCHMENT AREA OF LAKE GENEVA (LAC LÉMAN)
Lake Geneva is located in the Alps and of glacial origin is bordered by Switzerland in
the north and France in the south. The lake is divided in two parts, the "small lake" and
the "large lake" (Figure 10-4). The "small lake" in the west part has a volume of 3 km³, a
maximum depth of 76 m and a water surface of 81.2 km². The eastern "large lake" has
a volume of 86 km³, a maximum depth of 309.7 m and a water surface of 498.9 km².
Lake Geneva has a surface of 580.1 km² whereof 234.8 km² are located in France and
345.3 km² in Switzerland (cantons Waadt, Wallis and Geneva). The mean volume
come to 89 km³ and the mean rate of discharge between 1935 and 1996 were 250
m³/s. The theoretical retention time of the water is 11.4 years [CIPEL 200a].