『Abstract
At the regional scale, more and more questions are arising regarding
the evaluation of management strategies to minimize the nutrient
input into ground- and surface water. Therefore, the quantification
of the chemical transformation processes and the spatio-temporal
differentiation of the nitrate transport behavior at regional
scales are essential. The EU Water Framework Directive (WFD) stipulated
new sustainable management concepts in the face of climate change
and the change of land use systems. Considering the prospective
changes, a valid prediction of the substance flux using scale-dependent
adapted model tools is a necessity. The objective of this paper
is the parameterization of redox based denitrification dynamics
in groundwater via the entire flow path from recharge to discharge
by the geochemical proxies redox potential and Fe-concentration.
The used model approach Model of Diffuse Emissions via Subsurface
Trails (MODEST) combines GIS embedded grid-based conceptual groundwater
flow and substance transport modeling at larger scales with substance
degradation rates, the latter based on denitrification half-lives
between 6 months and 120 years determined for the individual compartments
of the modeled region, the State Brandenburg. The resulting regional
nitrate retention potential represents the basic information for
the evaluation of renovated, sustainable land and water management
approaches, mitigating diffuse nitrate pollution in the younger
Pleistocene glacial landscapes.
Keywords: Groundwater; Denitrification; Redox geochemistry; Conceptual
GIS modeling; North Central Europe』
Introduction
Materials and methods
Conceptual approach using classified hydrogeologic information
Denitrification rates as determined from identified geochemical
processes
Regional mapping of the geochemical findings
Results
Geochemical parameterization of floodplains
Geochemical parameterization of recharge areas
Geochemical parameterization of transit areas
MODEST modeling results
Summary and conclusions
References