D10: Impact of Contaminants - Hydromod

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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 84 of 136 directly to the Rhône river, downstream the Bourget Lake. Since effluents re-routing. phosphorus concentration in the lake is significantly decreasing. However, nitrate concentration in the lake is just a little decreasing Pesticides such as herbicides, insecticides and fungicides are used in agriculture like vine culture, cereal growing and orchards (cp. with the description of land use described before). Several products are used like e. g. diuron, simazine, alachlor, therbutylazine and lindane. Beside the agricultural usage there is also a non agricultural use of pesticides. An application takes place on rail roads, roads, highways in cities, on airports on golf courses and in forests (e. g. diuron, oxadiazon, gyphosate etc.). In the departement of Savoie 6-7 t herbicides are used for non agricultural application and 65 t for agricultural use [Chaton N., 1997]. Pesticide quantity used by year on the lake catchment area was estimated at 16 t in 1997 [Chaton N., 1998]. Monitoring Programme Unfortunately there are no data about surveys available so nothing can be said with certainty about the concentrations of the used pesticides in the water and sediment of Bourget Lake or some important feeders. 10.4 CATCHMENT AREA OF LOCH LOMOND In terms of surface area (70.6 km²), Loch Lomond is the largest body of fresh water in Scotland and the second largest in volume (around 2.6 x 10 9 m 3 ). It is situated 32 km to the north-west of Glasgow [SEPA 2000c]. The Loch Lomond basin is of glacial origin with deposited eroded material forming a dam at the southern end of the lake. The Lake is complex and varied in shape consisting of two main basins although there are a number of smaller subsidiary ones. The lake basin profile reflects the differences in the topography of the surrounding land. The top north part of the loch is long (around 20 km), narrow (maximum width of 1.5 km) and very deep (depths to 189.9 m) compared to the large wide (maximum width of 8.8 km) and shallow area (typically between 5 and 20 m depth at southern end) of the south end [SEPA 2000c]. The mean rate of discharge is 8.3 m³/s and the theoretical water retention time are 2 years. The Loch Lomond catchment area is 769 km² in size. This total area is made up of a lake surface of 71 km², a natural catchment area of 696 km² plus three areas of catchment capture around Loch Sloy and one area above the Endrick Water. At the Endrick river a number of streams are intercepted to supplement the flow to the loch. The natural catchment of Loch Lomond can be divided into two northern and two southern subcatchments based on their contrasting bedrock geology and topography [MAITLAND 1981]. This dichotomy has a major influence on the soil and the land use in both areas.
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 Figure 10-11: Catchment Area of Loch Lomond [SEPA, changed] Page 85 of 136 Loch Lomond's catchment is characterised by a relatively low mean altitude and gentle slopes with a high percentage of arable ground and base-rich rocks. For the River Clyde catchment as a whole are far more roads than in any of the Scottish catchments and relatively high population. More than half of Scotland's population, approximately 2.6 million, live within on hours drive of the lake [HAMILTON 1988], although most of these are outwith the catchment. In comparison to the other catchment areas of Lake Constance, Lake Geneva and Bourget Lake it has the lowest population. The extent of arable ground and base-rich
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D10: Impact of Contaminants - Hydromod

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