Details zur Publikation

Kategorie Textpublikation
Referenztyp Zeitschriften
DOI 10.1016/j.scitotenv.2023.164911
Volltext Autorenversion
Titel (primär) Stream restoration can reduce nitrate levels in agricultural landscapes
Autor Zhou, X.; Jomaa, S.; Yang, X.; Merz, R.; Wang, Y.; Rode, M.
Quelle Science of the Total Environment
Erscheinungsjahr 2023
Department ASAM; CATHYD
Band/Volume 896
Seite von art. 164911
Sprache englisch
Topic T4 Coastal System
Keywords River restoration; Sinuosity; mHM-Nitrate model; Stream denitrification; Assimilatory uptake
Abstract The EU Water Framework Directive (WFD) has emphasized that altered stream/river morphology and diffuse pollution are the two major pressures faced by European water bodies at catchment scales. Increasing efforts have been directed toward restoration to meet WFD standards for ecological health, but this work has achieved limited success. One challenge is that little is known about how morphological changes (i.e., re-meandering) may affect nitrate retention within whole stream networks. We investigated this issue in the well-monitored Bode catchment (3200 km2) in central Germany. First, we implemented a fully distributed process-based mHM-Nitrate model, exploring its performance over the period from 2015 to 2018. Second, we simulated the effects of restoring more natural stream morphology (i.e., increasing sinuosity) on nitrate retention. The mHM-Nitrate model performed well in replicating daily discharge and nitrate concentrations (median Kling-Gupta values of 0.78 and 0.74, respectively). Within the stream network, mean and standard deviation (SD) of gross nitrate retention efficiency was 5.1 ± 0.61 % and 74.7 ± 23.2 % in the winter and summer, respectively; this measure took into account both denitrification and assimilatory uptake. In the summer, the denitrification rate was about twice as high in a lowland sub-catchment dominated by agricultural lands as in a mountainous sub-catchment dominated by forested areas (median SD of 204 22.6 and 102 22.1 mg N m−2 d−1, respectively). Similarly, in the same season, the assimilatory uptake rate was approximately five times higher in streams surrounded by lowland agricultural areas than in streams in higher-elevation, forested areas (median SD of 200 ± 27.1 and 39.1 ± 8.7 mg N m−2 d−1, respectively). This suggests that restoration strategies targeted at lowland agricultural areas may have a greater potential for increasing nitrate retention. In our simulation, restoring stream sinuosity was found to increase net nitrate retention efficiency by up to 25.4 ± 5.3 %; greater effects were seen in small streams. Taken together, our results indicate that restoration efforts should consider augmenting stream sinuosity to increase nitrate retention and decrease nitrate concentrations at the catchment scale.
dauerhafte UFZ-Verlinkung
Zhou, X., Jomaa, S., Yang, X., Merz, R., Wang, Y., Rode, M. (2023):
Stream restoration can reduce nitrate levels in agricultural landscapes
Sci. Total Environ. 896 , art. 164911 10.1016/j.scitotenv.2023.164911