Evaluation of pesticides contents in cultivated soils in the Roujan catchment area.

The evaluation of soil moisture in different areas of the Roujan catchment area is carried out by measuring the moisture content of fresh soil samples.

Soil moisture assessment in different areas of the Kamech catchment area is carried out using soil tensiometry measurements carried out on different areas and at different depths of the Kamech site.

The Kamech basin is located north of Cap-Bon, in the governorate of Nabeul, on the border between the sub-humid and semi-arid Mediterranean climates. The average inter-annual rainfall is about 640 mm and the potential evapotranspiration is 1300 mm. The outlet of the basin is occupied by a hilly lake built in 1994 (140,000 m3 of initial capacity). The inter-annual flow coefficient is of the order of 10%-15% and the erosion of 15 t/ha/year. Land use is characterised by a cultivation rate close to 75% with, in order of importance: cereals, legumes and irrigated market gardening. This basin has been the subject of a monitoring of anthropogenic activities (land use and management, agricultural practices...), of agro-climatic variables, and of runoff and erosion since 1994 (+ pesticides more recently) at its outlet and since 2005 on 4 substations. This watershed is part of a network of 27 watersheds monitored under an agreement with the Tunisian Ministry of Agriculture (DGACTA).

These data correspond to a non-systematic monitoring of dissolved, particulate or total organic carbon contents in water (rain, surface overflow, underground water) in the Roujan catchment area.

Runoff and stream flow discharge have been monitored since 1994 at the outlet of the Kamech catchment, and since 2005 at four sub-catchment hydrological stations. Automatic sensors continuously collected and transmitted water level time series to servers in Montpellier (France). Verification and correction processes on the raw data, as well as the generation of elaborated data (e.g. calculation of runoff, discharge from water levels, modification of time steps, etc) are applied before integration of the data sets into the HYSAE database. The time series can be downloaded from an interactive map through the OMERE data portal accessible from this page.

Pesticide contents are determined on the suspended matter extracted by filtration (0,7µm) in runoff water. Contents allow quantification of particula transport of pesticides and allow too compare it to solute transport.