Nile flood peaks may jump this century
A basin-wide hydrology model driven by 30 CMIP6 climates projects much larger 50- and 200-year Nile floods at Dongola by 2100.
Source
Nile basin flow regimes under 21<sup>st</sup> century climate variability
Study at a glance
- Design
- Computational / modelling — SWAT+ Nile hydrology forced by bias-corrected CMIP6 members under SSP2-4.5 and SSP5-8.5
- N
- N=30 · 30 CMIP6 climates (high/median/low members per SSP run through SWAT+)
- Population
- Nile basin streamflow regimes at Dongola under 21st-century climate scenarios
- Outcome
- Projected increases in 50- and 200-year flood peaks by 2100
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
The authors calibrated SWAT+ (34 subbasins, 234 HRUs) to 1984–1997 gauges, bias-corrected NEX-GDDP CMIP6 rain with QQM, then ran high/median/low members of SSP2-4.5 and SSP5-8.5 through 2100 and fitted log-Pearson III flood peaks.
What they found
Historical 50- and 200-year peaks are 13,400 and 14,900 m³/s. Median SSP2-4.5 raises them to 21,800 and 24,100 m³/s; SSP5-8.5 exceeds 24,700 and 27,400 m³/s. Extreme streamflow intensity rises 49–63% (SSP2-4.5) and 73–85% (SSP5-8.5). A historical 100-year flood (~14,200 m³/s) occurs about every 4 years (SSP2-4.5) or 2.75 years (SSP5-8.5). Mean AMS rain rises ~29% and ~41%.
The limits
What it doesn't show
SWAT+ was calibrated on a short 1984–1997 window and does not fully resolve GERD operations. CMIP6 still disagrees on the sign of mean Nile rain. Extreme-value fits have wide 5th–95th percentile bands. Lake Nasser operations can still divert floods.
Key terms
- SWAT+
- A watershed hydrology model that routes rainfall through soils and channels to streamflow.
- Dongola station
- A key Nile gauge in northern Sudan used as the basin-outlet evaluation point.
- Log-Pearson Type III (LP3)
- A frequency distribution fitted to annual maximum streamflow to estimate return-period floods.
Flashcards
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Quiz yourself
Historical 50-year Nile peak at Dongola is about:
Common questions
Is the basin getting wetter already?
GRACE TWS rose 0.24 cm/yr (2002–2017) and 2.4 cm/yr (2018–2024), consistent with wetter recent decades.
Why pick three GCMs per SSP?
Highest, median, and lowest annual-max precipitation members span the 30-model envelope without running all 30 through SWAT+.
Does this include sea-level rise?
No: it is a river-flood hydrology study at Dongola, far upstream of the delta.
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