Modeling Climate and Management Change Impacts on Water Quality and In-Stream Processes in the Elbe River Basin

Abstract

Eco-hydrological water quality modeling for integrated water resources management of river basins should include all necessary landscape and in-stream nutrient processes as well as possible changes in boundary conditions and driving forces for nutrient behavior in watersheds. The study aims to assess possible impacts of the changing climate (ENSEMBLES climate scenarios) and/or land use conditions on resulting river water quantity and quality in the large-scale Elbe river basin by applying a semi-distributed watershed model of intermediate complexity (SWIM) with implemented in-stream nutrient (N+P) turnover and algal growth processes. The calibration and validation results revealed the ability of SWIM to satisfactorily simulate nutrient behavior at the watershed scale. Analysis of 19 climate scenarios for the whole Elbe river basin showed a projected increase in temperature (+3˝C) and precipitation (+57 mm) on average until the end of the century, causing diverse changes in river discharge (+20%), nutrient loads (NO 3 -N:´5%; NH 4 -N:24%; PO 4 -P: +5%), phytoplankton biomass (´4%) and dissolved oxygen concentration (´5%) in the watershed. In addition, some changes in land use and nutrient management were tested in order to reduce nutrient emissions to the river network.

Challenges of Reducing Phosphorus Based Water Eutrophication in the Agricultural Landscapes of Northwest Europe

“…As said, while the impacts of projected climate on river hydrological regimes are widely studied, fewer projections of the likely impact on future P pollution in running waters exist FIGURE 3 | Sketch illustrating the concept of landscape biogeochemistry applied to dissolved, colloidal and particulate P emissions in catchments (adapted from Gu et al, 2017). Frontiers in Marine Science | www.frontiersin.org 9 August 2018 | Volume 5 | Article 276 (Whitehead et al, 2009;Dunn et al, 2015;Mehdi et al, 2015;Hesse and Krysanova, 2016;Ockenden et al, 2016Ockenden et al, , 2017. This may be related to the continuing complexity of human activities and its impact on water quality across a range of different spatial scales, including the small headwater catchment scale, while climate scientists traditionally focus their work mostly only at the larger scales (Michalak, 2016).…”

“…Furthermore, it is difficult to disentangle direct climate change impacts from the indirect consequences of adaptive land use mediated by climate change (Bussi et al, 2016(Bussi et al, , 2017. Thus, water quality modeling with respect to climate change impacts is subject to more weaknesses and uncertainties compared to rainfallrunoff modeling (Hesse and Krysanova, 2016). Understanding the impact of climate change on water quality will require an understanding of the link between P concentrations, loads and recipient freshwater ecosystems within the context of multiple stressors (Whitehead and Crossman, 2012;Crossman et al, 2013), including point source and diffuse pollution sources and water abstraction.…”

How EU policies could reduce nutrient pollution in European inland and coastal waters?

“…River Web link (Cozzi et al, 2018) Danube, Ebro, Po, Rhone doi:10.3390/w11010001 (Friedland et al, 2019) Oder https://doi.org/10.3389/fmars.2018.00521 (Hartmann et al, 2011) Rhine https://doi.org/10.1007/s10201-010-0322-4 (Hesse and Krysanova, 2016) Elbe https://doi.org/10.3390/w8020040 (Howden et al, 2010) Thames DOI: 10.1002/hyp.7835 Adige, Drin, Ebro, Po, Rhone, Tiber DOI 10.1007/s10661-011-2313-2 (Kauppila and Koskiaho, 2003) Kemijoki https://doi.org/10. 2166/nh.2003.0004 (Lajaunie-Salla et al, 2018 Garonne https://doi.org/10.1007/s11356-018-3035-6 S5.…”

Water Resource Variability and Climate Change

“…Hesse and Krysanova [28] simulate the impacts of climatic shifts and changing management practices on water quality and in-stream processes in the Elbe River Basin using a semi-distributed watershed model (SWIM) with implemented in-stream nutrient (N+P) turnover and algal growth processes. The set of modeled climate scenarios show a projected increase in temperature (+3 • C) and precipitation (+57 mm) on average until the end of the century, leading to varied changes in discharge (+20%), nutrient loads (NO 3 -N: 5%; NH 4 -N: 24%; PO 4 -P: +5%), phytoplankton biomass (4%), and dissolved oxygen concentration (5%) in the Elbe River Basin.…”