Reservoir 64.0 m Head 0 m Inflow 0 m³/s Turbines 0 m³/s Spillway 0 m³/s Power 0 MW Unit efficiency 0 % Level ok Clock day 1 00:00 FPS 0
Hero Spillway Turbines Runners Reservoir Top
Rain and snowmelt fill the reservoir (the lake behind the dam). Water either runs through the penstocks to four turbines (the generators glow with output power) or leaves over the spillway gates . Drag to rotate, wheel to zoom.
WebGL is not available here — the plant model on the right still runs.
Hydroelectric Dam Cutaway: Reservoir Balance, Spillway Gates, Penstocks and Four Francis Units
One river, one lake, four turbines and four gates. Balance what flows in against what flows out, and see how head, flow and efficiency make megawatts.
Educational model: one lumped reservoir, steady-flow turbines, model efficiency curves. It is not a design, dam-safety or flood-forecast tool.
Scenarios
River and reservoir
Turbines
Governor (demand): on Daily demand curve: off
Spillway
Auto spillway: off Flood wave
Pause Reset Quality: High
Results
Reservoir level and power over time
Level: green = normal full level (65 m), orange = flood limit (72 m); the crest is at 75 m. Flows: cyan = inflow, blue = turbines, white = spillway.
Turbine hill and spillway rating
One Francis unit: efficiency versus its flow at the current head (peak near 82 % of full gate). Spillway: discharge of all gates in use versus lake level at the current gate opening.
Missions
Independent numerical checks
Controls help Drag or one finger: rotate. Wheel or pinch: zoom. Buttons Hero / Spillway / Turbines / Runners / Reservoir / Top (keys 1–6) jump to camera presets. With the governor on, the gates of the running units open just enough to deliver the demand. Switch it off to set the wicket-gate opening yourself and find the efficient range. The clock runs at the chosen speed (hours of plant time per real second); Space pauses it. The science
Water balance. The lake is one volume: A(z)·dz/dt = Qin − Qturbines − Qspill , with surface area A(z) = A0 + k(z − z0 ) (10 km² at 60 m, growing with level). It is integrated with a 4th-order Runge-Kutta step. Evaporation, seepage and sediment are ignored.
Power. P = η·ρ·g·Q·Hn . The gross head is the lake level minus the tailwater level; the penstock friction hf = K·Q² (Darcy-Weisbach for a 4.4 m pipe, 90 m long, f = 0.012) gives the net head Hn = H − hf . With a fixed efficiency the maximum power of a penstock would be at Hn = 2H/3 (a check below); a real plant stays far from it because efficiency matters more than squeezing flow.
Turbine. A Francis unit passes Q = x·Qr ·√(Hn /Hr ) for wicket-gate fraction x (full gate 110 m³/s at 60 m). Its efficiency is a model parabola, best near 82 % of full gate, with a fall-off away from the design head. The numbers are illustrative, not from a manufacturer [check against a hydraulic-machinery textbook].
Spillway gates. A gate below the surface acts as an orifice, Q = Cd ·b·a·√(2g(h − a/2)); once it is lifted clear of the water it becomes a free weir, Q = (2/3)Cd ·1.06·b√(2g)·h3/2 , with h the depth over the sill (55 m). The two formulas meet exactly at a = h. The tailwater level rises with total outflow through a model rating curve.
Simplifications. Steady flow in the penstocks (no water hammer), one tailwater level for all units, no ice, silt, fish passage or sediment gates, and no grid frequency control. Not affiliated with any operator or manufacturer. The dam, hills and equipment are generic.
Sources of this kind: hydropower engineering textbooks, open data of reservoir operation, hydraulic-structure design manuals.
Made with Blender (dam, turbines, generators, landscape) and rendered with Three.js.