WETTRANS: a flow-path-oriented decision-support system for the assessment of water and nitrogen exchange in riparian peatlands

摘要

Environmental authorities require quantitative predications of the nitrogen retention ability of riparian peatlands to aid in the selection of effective water management strategies for restoration. To support this decision-making process, a matrix model connecting flow paths and nitrogen transformation was developed with a quasi-stationary mass balance approach. The model concept is based on the assumptions that wetlands (1) receive water and nitrogen along several hydrological pathways, and (2) transformation of nitrogen occurs inside the wetland with different efficiencies, depending on the transition pattern between inflow and outflow pathways. These assumptions are formalized in a set of vectors describing the amount of water and the nitrogen concentration for each inflow pathway, a water distribution matrix between the inflowing water and several outflow pathways, a nitrogen transformation coefficient matrix of each inflow and outflow combination and, finally, two outflow vectors with the amount of water flowing out and the calculated nitrogen concentrations of each outflow pathway. The matrix model is applied to a drained valley peatland in order to quantify the effect of different water management options on an increase in nitrogen retention.