🏔️ Himalayan GLOF Dynamics & Spillway Simulator China-Nepal Corridor v2.6

Hydro-mechanical moraine breach calculator, displacement wave trigger modeling, and downstream transboundary flood routing for the Poiqu / Bhote Koshi and Arun river basins.
Scenario Presets:
⚙️ Glaciological & Dam Physics
32.0 M m³
Total impounded water behind terminal moraine dam.
4.5 m
Vertical height difference between water level and moraine crest.
65 m
Total height of terminal debris/moraine embankment.
Internal ice thaw accelerates catastrophic breach widening.
6.0 m
Seiche / displacement wave height generated by ice calving.
🛠️ Emergency Mitigation Measures
0.0 m
Preemptive excavator trenching to draw down lake level safely.
High-Volume Siphon Pipes
🌊 Moraine Cross-Section & Breach Dynamics
Lake El: 4,780 m
Status: Intact
Seepage: 2.1 m³/s
Elapsed Time: 0.0 hrs
Sim Speed:
Peak Discharge (Q_p)
4,820 m³/s
Froehlich (2008) empirical
Time to Peak (t_p)
1.8 hrs
Breach maturation interval
Final Breach Width
78.4 m
Trapezoidal breach notch
Total Released Vol
24.5 M m³
Drainage fraction: 76.5%
Breach Outflow Hydrograph (Q vs Time) Current Q: 0 m³/s
6k m³/s 3k m³/s 0 0h 3h 6h 9h 12h
— Unmitigated Hydrograph --- With Spillway/Siphon
📍 Transboundary Downstream Routing
Poiqu → Bhote Koshi
Longitudinal hydraulic wave propagation along Nepal-China highway gorge (80 km reach):
Civil Defense & Cross-Border Protocol
🚨 RED ALERT: EVACUATION ORDER
Immediately trigger transboundary siren telemetry, shut down downstream hydropower penstocks, and evacuate low-lying highway bridges within 15 minutes.
Hydropower Intake Inundation Risk: Extreme (12.4m Surge)
Highway Bridges at Risk: 4 Major Spans
Transboundary Notification Lead-Time: 28 min to Nepal Border

1. Froehlich (2008) Peak Breach Discharge Equation:
Q_p = 0.607 · V_w^0.295 · H_w^1.24 where V_w is actual drained volume (m³) and H_w is hydraulic breach head (m). Used by the USGS and ICIMOD for glacial outburst modeling.

2. Costa (1985) Dam-Breach Envelope:
Q_p,max = 0.0181 · (V_o · H_d)^0.42 providing an upper-bound check against historical Himalayan outburst benchmarks (e.g., Dig Tsho 1985, Luggye 1999, Cirenmaco 1981).

3. Downstream Wave Routing & Attenuation:
Kinematic & Muskingum-Cunge diffusion wave approximation through steep bedrock gorges (slopes S₀ = 0.035 to 0.070):
c_k = (5/3) · v = (5/3) · (1/n) · R^(2/3) · S_0^(1/2) with peak discharge decay Q(x) = Q_p · exp(-k · x).