文档介绍：Journal of Hydrology 236 (2000) 139–152
ate/jhydrol
Relations between triazine flux, catchment topography and distance
between maize fields and the work
F. Colina,*, C. Puecha, G. de Marsilyb,1
aUMR “Syste`mes et Structures Spattiaux”, Cemagref-ENGREF 500, rue . Breton 34093, Montpellier Cedex 05, France
bUMR “Structure et Fonctionement des Syste`mes Hydriques Continentaux”, Universite´ P. et M. Curie 4, Pl. Jussieu 75252,
Paris Cedex 05, France
Received 5 October 1999; revised 27 April 2000; accepted 19 June 2000
Abstract
This paper puts forward a methodology permitting the identification of farming plots contributing to the pollution of surface
water in order to define the zones most at risk from pesticide pollution. We worked at the scale of the small agricultural
catchment (– km2) as it represents the appropriate level anisation for agricultural land. The hypothesis tested was:
the farther a field undergoing a pesticide treatment is from a work, the lower its impact on pollution at the catchment
outlet.
The study area, the Sousson catchment (120 km2, Gers, France), has a “herring bone” structure: 50 independent tributaries
supply the main drain. Pesticide sales show that atrazine is the most frequently pound although it is only used for
treating maize plots and that its application rate is constant. In two winter inter-storm measurement exercises, triazine flux
values were collected at about 30 independent sub-basin outlets.
The contributory areas are defined, with the aid of a GIS, as different strips around the work. The correlation
between plots under maize in contributory zones and triazine flux at related sub-basin outlets is studied by using non-parametric
and linear correlation coefficients. Finally, the most pertinent contributory zone is associated with the best correlation level.
A catchment typology, based on a slope criterion, allows us to conclude that in steep slope catchments, the contributory area
is best defined