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Climate change — watershed modeling

What does a warmer climate do to a river's water?

We run a basin's SWAT+ model on downscaled projections of the past and the future from the same climate model, and compare the two. On one Michigan basin, 20 climate models agree on the direction of most changes and disagree on their size, and this page shows both.

See the 20-model result
Rogue RiverUSGS 04118500 · 667.02 km²

20 climate models, one basin

Rogue River, Michigan (USGS 04118500, 667.02 km² modelled). Each dot below is one downscaled CMIP6 climate model under SSP2-4.5, run through one uncalibrated SWATGenX SWAT+ model. It shows the change from 1985–2014 to 2071–2100.

one climate modelACCESS-CM2median of 20 modelsno change
Air temperaturemedian +3.53 °Crange +2.33 °C to +5.07 °C20 of 20 warmer
no change+2.33 °C+5.07 °CINM-CM4-8: +2.33 °CMPI-ESM1-2-LR: +2.45 °CFGOALS-g3: +2.68 °CINM-CM5-0: +2.75 °CMPI-ESM1-2-HR: +2.88 °CMIROC6: +3.03 °CGFDL-ESM4: +3.03 °CMRI-ESM2-0: +3.23 °CBCC-CSM2-MR: +3.47 °CNorESM2-LM: +3.51 °CAWI-CM-1-1-MR: +3.55 °CNorESM2-MM: +3.58 °CACCESS-ESM1-5: +3.64 °CGFDL-CM4: +3.92 °CEC-Earth3-Veg: +3.93 °CKACE-1-0-G: +4.31 °CACCESS-CM2: +4.49 °CEC-Earth3: +4.49 °CCanESM5: +4.64 °CTaiESM1: +5.07 °C
Evapotranspirationmedian +38.5 mm/yrrange +9.3 mm/yr to +55.2 mm/yr20 of 20 higher
no change+9.3 mm/yr+55.2 mm/yrAWI-CM-1-1-MR: +9.3 mm/yrBCC-CSM2-MR: +11.3 mm/yrNorESM2-LM: +18.4 mm/yrEC-Earth3-Veg: +21.6 mm/yrINM-CM5-0: +22.5 mm/yrINM-CM4-8: +33.4 mm/yrACCESS-ESM1-5: +33.9 mm/yrACCESS-CM2: +34.8 mm/yrMPI-ESM1-2-HR: +37.5 mm/yrMPI-ESM1-2-LR: +38.0 mm/yrMIROC6: +39.0 mm/yrGFDL-CM4: +41.3 mm/yrFGOALS-g3: +42.9 mm/yrNorESM2-MM: +45.6 mm/yrGFDL-ESM4: +45.8 mm/yrTaiESM1: +48.0 mm/yrEC-Earth3: +49.5 mm/yrKACE-1-0-G: +50.1 mm/yrCanESM5: +52.2 mm/yrMRI-ESM2-0: +55.2 mm/yr
Share of precipitation falling as snowmedian −0.058range −0.099 to −0.03020 of 20 lower
no change−0.099−0.030TaiESM1: −0.099MIROC6: −0.084EC-Earth3: −0.079ACCESS-ESM1-5: −0.073MRI-ESM2-0: −0.073GFDL-CM4: −0.070CanESM5: −0.070INM-CM5-0: −0.065EC-Earth3-Veg: −0.060NorESM2-LM: −0.060INM-CM4-8: −0.056AWI-CM-1-1-MR: −0.055MPI-ESM1-2-LR: −0.055GFDL-ESM4: −0.051MPI-ESM1-2-HR: −0.043ACCESS-CM2: −0.042NorESM2-MM: −0.041KACE-1-0-G: −0.039FGOALS-g3: −0.031BCC-CSM2-MR: −0.030
Timing of annual streamflow (centre of mass)median −11.8 daysrange −20.1 days to +4.0 days19 of 20 earlier
no change−20.1 days+4.0 daysNorESM2-MM: −20.1 daysNorESM2-LM: −19.8 daysKACE-1-0-G: −17.9 daysGFDL-CM4: −14.5 daysMPI-ESM1-2-HR: −14.2 daysACCESS-ESM1-5: −14.2 daysBCC-CSM2-MR: −14.1 daysEC-Earth3-Veg: −13.9 daysACCESS-CM2: −13.7 daysMPI-ESM1-2-LR: −12.2 daysCanESM5: −11.3 daysTaiESM1: −11.0 daysGFDL-ESM4: −10.4 daysFGOALS-g3: −9.3 daysAWI-CM-1-1-MR: −5.7 daysMIROC6: −5.7 daysEC-Earth3: −5.0 daysMRI-ESM2-0: −4.2 daysINM-CM5-0: −3.8 daysINM-CM4-8: +4.0 days
Outlet streamflowmedian +13.5 %range −10.3 % to +26.3 %18 of 20 higher
no change−10.3 %+26.3 %AWI-CM-1-1-MR: −10.3 %INM-CM5-0: −2.2 %NorESM2-LM: +5.9 %INM-CM4-8: +6.2 %KACE-1-0-G: +6.9 %BCC-CSM2-MR: +7.5 %EC-Earth3-Veg: +7.7 %ACCESS-CM2: +9.1 %GFDL-CM4: +9.5 %MPI-ESM1-2-LR: +12.8 %MIROC6: +14.1 %EC-Earth3: +16.9 %MRI-ESM2-0: +17.2 %FGOALS-g3: +18.4 %TaiESM1: +19.4 %CanESM5: +21.0 %NorESM2-MM: +22.5 %MPI-ESM1-2-HR: +22.5 %GFDL-ESM4: +24.8 %ACCESS-ESM1-5: +26.3 %

Change, 2071–2100 against 1985–2014, SSP2-4.5, 20 downscaled CMIP6 models, one uncalibrated SWATGenX SWAT+ model, Rogue River, Michigan.

Timing

In 19 of the 20 climate models, spring flow arrives earlier — by a median of about 12 days (range −20.1 days to +4.0 days).

Streamflow

Outlet streamflow rises in 18 of 20 models, by a median of +13.5 %. The models range from −10.3 % to +26.3 %, and 2 show a decline. For this quantity the spread is the result.

Why one climate model is not enough

The highlighted dot, ACCESS-CM2, is among the warmest of the 20 models, yet its streamflow change ranks 13th of 20, below the median. How warm a climate model runs does not decide what it does to the river, which is why one climate model is not enough.

IPSL-CM6A-LR was requested and excluded because it did not complete, so every median is over 20 models. Precipitation in the projections changes by a median of +8.4 % (range −3.2 % to +13.5 %).

What this is, and what it is not

  • One basin. It says nothing about how any other river will respond.
  • One default, uncalibrated SWAT+ model, which is the right choice for testing the method and not for a management decision.
  • One emissions scenario (SSP2-4.5) and one pair of periods (1985–2014 against 2071–2100).
  • A comparison between two model runs, not a forecast for a particular year.

Climate scenarios for your own model

Climate scenarios for a SWATGenX model are coming with V2. Until then we run them for you on your own model, as a quoted service.