Climate-change impacts on hydrology and nutrients in a Danish lowland river basin

被引:134
作者
Andersen, Hans Estrup
Kronvang, Brian
Larsen, Soren E.
Hoffmann, Carl Christian
Jensen, Torben Strange
Rasmussen, Erik Koch
机构
[1] Natl Environm Res Inst, DK-8600 Silkeborg, Denmark
[2] Danish Hydraul Inst, DK-2970 Horsholm, Denmark
关键词
climate-change; modelling; runoff; nutrient loss; nutrient retention; total nitrogen; total phosphorus; NAM; Mike; 11; TRANS;
D O I
10.1016/j.scitotenv.2006.02.036
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
The Mike 11-TRANS modelling system was applied to the lowland Gjern river basin in Denmark to assess climate-change impacts on hydrology and nitrogen retention processes in watercourses, lakes and riparian wetlands. Nutrient losses from land to surface waters were assessed using statistical models incorporating the effect of changed hydrology. Climate-change was predicted by the ECHAM4/OPYC General Circulation Model (IPCC A2 scenario) dynamically downscaled by the Danish HIRHAM regional climate model (25 km grid) for two time slices: 1961-1990 (control) and 2071-2100 (scenario). HIRHAM predicts an increase in mean annual precipitation of 47mm (5%) and an increase in mean annual air temperature of 3.2 degrees C (43%). The HIRHAM predictions were used as external forcings to the rainfall-runoff model NAM, which was set: up and ran for 6 subcatchments within and for the entire, Gjern river basin. Mean annual runoff from the river basin increases 27mm (7.5%, p < 0.05) when comparing the scenario to the control. Larger changes, however, were found regarding the extremes; runoff during the wettest year in the 30-year period increased by 58mm (12.3%). The seasonal pattern is expected to change with significantly higher runoff during winter. Summer runoff is expected to increase in predominantly groundwater fed streams and decrease in streams with a low base-flow index. The modelled change in the seasonal hydrological pattern is most pronounced in first- or second-order streams draining loamy catchments, which currently have a low base-flow during the summer period. Reductions of 40-70% in summer runoff are predicted for this stream type. A statistical nutrient loss model was developed for simulating the impact of changed hydrology on diffuse nutrient losses (i.e. losses from land to surface waters) and applied to the river basin. The simulated mean annual changes in TN loads in a loamy and a sandy subcatchment were, respectively, +2.3 kg N ha(-1) (8.5%) and + 1.6kg N ha(-1) (6.9%). The rainfall-runoff model and the nutrient loss model were chained with Mike I I-TRANS to simulate the combined effects of climate-change on hydrology, nutrient losses and nitrogen retention processes at the scale of the river basin. The mean annual TN export from the river basin increased from the control to the scenario period by 7.7%. Even though an increase in nitrogen retention in the river system of 4.2% was simulated in the scenario period, an increased in-stream TN export resulted because of the simulated increase in the diffuse TN transfer from the land to the surface-waters. (c) 2006 Elsevier B.V. All rights reserved.
引用
收藏
页码:223 / 237
页数:15
相关论文
共 38 条
[21]   Climate change scenarios and runoff response in the Mulde catchment (Southern Elbe, Germany) [J].
Menzel, L ;
Bürger, G .
JOURNAL OF HYDROLOGY, 2002, 267 (1-2) :53-64
[22]  
Möller J, 2000, Z EXP PSYCHOL, V47, P67
[23]  
Nash J.E., 1970, J Hydrol, V10, P282, DOI DOI 10.1016/0022-1694(70)90255-6
[24]  
OLESEN JE, 2004, DJF RAPPORT, V109
[25]   Nitrate nitrogen in surface waters as influenced by climatic conditions and agricultural practices [J].
Randall, GW ;
Mulla, DJ .
JOURNAL OF ENVIRONMENTAL QUALITY, 2001, 30 (02) :337-344
[26]   Differences in temperature, organic carbon and oxygen consumption among lowland streams [J].
Sand-Jensen, K ;
Pedersen, NL .
FRESHWATER BIOLOGY, 2005, 50 (12) :1927-1937
[27]  
Scharling M., 1999, 9912 DAN MET I, V48
[28]  
SILGRAM M, 2004, 82004 EUROPHARP
[29]  
SVENDESN LM, 1992, THESIS NATL ENV RES
[30]   DYNAMICS OF PHOSPHORUS-COMPOUNDS IN A LOWLAND RIVER SYSTEM - IMPORTANCE OF RETENTION AND NONPOINT SOURCES [J].
SVENDSEN, LM ;
KRONVANG, B ;
KRISTENSEN, P ;
GRAESBOL, P .
HYDROLOGICAL PROCESSES, 1995, 9 (02) :119-142