Arbeitspapier/Forschungsbericht

Jahr der Veröffentlichung: 2009

URL: https://www.kompetenz-wasser.de/wp-content/uploads/2017/05/kwb_aquisafe_d_2_3_aug_2009.pdf

Abstract: 

The Aquisafe project aims at mitigation of diffuse pollution from agricultural sources to
protect surface water resources. The first project phase (2007-2009) focused on the
review of available information and preliminary tests regarding
(i) most relevant contaminants,
(ii) system-analytical tools to assess sources and pathways of diffuse agricultural
pollution,
(iii) the potential of mitigation zones, such as wetlands or riparian buffers, to reduce
diffuse agricultural pollution of surface waters and
(iv) experimental setups to simulate mitigation zones under controlled conditions.
The present report deals with (ii), testing the biogeochemical model Soil and Water
Assessment Tool (SWAT) on the watershed of the Ic in Brittany, France, to evaluate
scenarios for reduction of nitrate in the stream water. The model has been calibrated in
several steps, each including additional information on the watershed. For the last
calibration the hydrologic model predictions showed fair results with a Nash-Sutcliffe
Efficiency of 0.53 at the watershed outlet.
The scenarios cover fertilizer reduction and the introduction of wetlands. Decrease of
nitrogen input was applied on a) selected subbasins, b) on drained fields, c) all
agricultural fields; wetlands were placed at three model subbasins. Three most effective
measures according to scenario analysis were a) 50% fertilizer reduction in selected
subbasins resulting in a 6.2% reduction of nitrate loads, b) wetlands draining 30% of the
subbasin area with a 5.4% reduction of nitrate loads, c) 10% fertilizer reduction for all
agricultural fields with 4.6% reduction of nitrate loads.
The management goal for the watershed is the meeting of drinking water threshold at the
watershed outlet. The analysis of observed data revealed that nitrate loads would have
to be reduced by 17% on average to reach that goal. Consequently, none of the tested
measures achieves a sufficient reduction. Combined measures such as enhanced
fertilizer management and concurrent introduction of wetlands seem to be the most
promising way to approach the drinking water threshold.

Harvard-Zitierstil: Julich, S., Frede, H. and Breuer, L. (2009) Hydrological and nitrate modelling for the River Ic in Brittany (France) - Simulation results and pre-liminary scenario analysis : Project acronym: AQUISAFE 1 Extension. Berlin: KompetenzZentrum Wasser Berlin gGmbH. https://www.kompetenz-wasser.de/wp-content/uploads/2017/05/kwb_aquisafe_d_2_3_aug_2009.pdf

APA-Zitierstil: Julich, S., Frede, H., & Breuer, L. (2009). Hydrological and nitrate modelling for the River Ic in Brittany (France) - Simulation results and pre-liminary scenario analysis : Project acronym: AQUISAFE 1 Extension. KompetenzZentrum Wasser Berlin gGmbH. https://www.kompetenz-wasser.de/wp-content/uploads/2017/05/kwb_aquisafe_d_2_3_aug_2009.pdf