Stream water contamination by fertilizer, Gers, France.
A study site monitored since 1983This small catchment (3.5 km²) has been studied in term of nitrate concentration in stream using a high frequency sampling protocol.
AZF-Total Fina have funded the monitoring from 1983 to 2011. The water sampling and analyses have been outsourced to a private laboratory in 2000 and to ECOLAB, a public research laboratory in 2006. The "Association des agriculteurs d'Auradé" has been created to implement best management practices to decrease nitrate and pesticide contamination. Both ECOLAB and CESBIO have worked on this site for their respective research objectives. The catchment has been recently classified in BVRE label (historically, study sites strongly equipped for decades to monitor hydrology, chosen and monitored by a scientific panel). . |
A continuous sampling protocol
To investigate the real variation of concentration during flood events, a protocol based on newly sonde technologies has been designed to monitor a continuous nitrate signal at the outlet of the catchment.
Ref : Ferrant et al., 2012 In collaboration with TOTAL-FINA, AKKA Technology |
Cropping pattern, climate variability, hydrological processes impacts on nitrate fluxes
Dataset used to simulate river discharge and nitrate concentration / Cumulative observed and simulated discharge and nitrate fluxes using two agro-hydrological models.
Two agro-hydrological model have been calibrated on the Auradé catchment data set. The aim is to simulate the observed water discharge and nitrate fluxes during 14 years using climatic, soil, aquifer physical data, the cropping pattern and associated agricultural practices.
The comparison of both model application is reported in this publication (Ferrant et al., 2011). It explores the ubiquity of hydrological modelling methods and give an idea of how far the simulations are from the reality.
In collaboration with CESBIO, TOTAL-FINA and INRA-SAS.
The comparison of both model application is reported in this publication (Ferrant et al., 2011). It explores the ubiquity of hydrological modelling methods and give an idea of how far the simulations are from the reality.
In collaboration with CESBIO, TOTAL-FINA and INRA-SAS.
A modelling tool to estimate the agricultural changes in term of nitrate fluxes reduction
One of the models has been evaluated to be more relevant to test agricultural scenarii in this context.
The Best Management Practices (BMPs) that have been designed and set up in the catchment since 1992 have then evaluated by modelling. A systematic catch crop implementation in the winter wheat- sunflower cropping pattern has been simulated The results of this study are submitted to Agricultural Water Management journal.
In collaboration with INRA-SAS and INRA-AGIR
The Best Management Practices (BMPs) that have been designed and set up in the catchment since 1992 have then evaluated by modelling. A systematic catch crop implementation in the winter wheat- sunflower cropping pattern has been simulated The results of this study are submitted to Agricultural Water Management journal.
In collaboration with INRA-SAS and INRA-AGIR
A modelling tool to up-scale the study results
The calibration and simulation done at the small catchment level is then used for a same geomorphological / agricultural region (hilly clayey calcareous substrate with winter wheat sunflower cropping pattern) to enhance simulations at the regional level (Save catchment, 1000 km²). The brown catchments in the figure represent the concerned area.
In collaboration with Cemagref-IRSTEA