MOUNTAIN RESERVOIR · READING THE CATCHMENT FROM ORBIT
How much electricity is in the snow? A dam is fed by its catchment — and the catchment is visible from orbit.
A hydropower operator knows the reservoir. What it does not know is the future inflow: how much water will melt out of the snowpack, how much evaporation will take, how much rain will add. We observe the whole catchment from orbit and turn it into an inflow forecast weeks ahead. This page is a method study on a representative mountain catchment; the plotted curves are illustrative.
BRIEFINGAS OF 2026-06-30WEEKLY CADENCEANALYSIS DESK: ORBISPECTv1.0
READ ACROSS THE WHOLE CATCHMENT FROM ORBIT, THE INFLOW SIGNAL LEADS THE RIVER GAUGE BY 2–6 WEEKS — THE WINDOW IN WHICH TURBINES AND RESERVE LEVEL CAN STILL BE PLANNED.
The water that drives the turbine is observable before it arrives. Snowpack water content, catchment precipitation and evaporation, and soil moisture are read across the whole contributing area from orbit — an inflow signal that leads the river gauge rather than trailing it. HIGH ON OBSERVABILITY
The output is a banded forecast, not a single number. Every inflow estimate carries a P10–P90 uncertainty band; the spread is the product, mapping onto turbine scheduling, flood-reserve level and contracted-energy value. HIGH ON METHOD
Lead-time is conditional, and the conditions are known. The 2–6 week horizon is strongest where inflow is snowmelt-driven and the catchment is well observed. It shortens for flashy rain-driven events, and where persistent cloud thins the optical record. Radar carries the signal through cloud, but it does not close every gap. MODERATE
Outlook — the band narrows as the melt season is observed out. If the snowmelt regime holds, the inflow forecast band should tighten through the spring melt as more passes accumulate over the catchment; a flashy rain-driven event would widen it. The narrowing is checkable against national river gauges. FORECAST · MODERATE
Two independent layers converge here: snow and surface-water layers from passive-microwave, optical, radar and altimetry sensing, and catchment precipitation and evapotranspiration estimates. The inflow judgment sits where they agree — neither layer alone would carry it.
RESERVOIR CATCHMENT
whole basinthe full mountain catchment upstream of the dam — every pixel observed from orbit every few days
WHAT WE WEIGH
3 streamssnowpack and its water content · catchment precipitation and evaporation · soil moisture — from satellite constellations
HORIZON
2–6 weeksinflow forecast with an uncertainty band — enough to plan turbine operation and reserve level
The snow store becomes the inflow wave — visible before the gauge
SNOW (SWE)INFLOW
ILLUSTRATIVE CURVE (METHOD DEMO): SPRING MELT TURNS THE SNOW STORE INTO AN INFLOW WAVE — VISIBLE FROM ORBIT BEFORE A RIVER GAUGE REGISTERS IT.
Inflow forecast — P10–P90 band
P50P10–P90OBSERVED
ILLUSTRATIVE CURVE (METHOD DEMO): THE UNCERTAINTY BAND NARROWS AS THE CATCHMENT IS WELL OBSERVED — THE OPERATOR GETS SCENARIOS, NOT A SINGLE NUMBER.
How it works — without opening the engine
1. The reservoir is a battery; the snow is its charger. Through winter the catchment stores water in its snowpack. From orbit we measure how much water actually sits in the snow (not just where it lies) — so we know how much energy is "waiting in the mountains" before it runs off.
2. A catchment water balance, not a backward-looking reading. A river gauge tells you what already happened; we estimate what is still coming: precipitation minus evaporation minus infiltration — for each part of the catchment separately, every few days, even through cloud, where radar carries the signal.
3. The operator gets a decision, not data. An inflow forecast with a P10–P90 band maps directly onto the turbine operating plan, the flood-reserve level and the value of energy under contract. Method details are shared with clients — results are validated publicly against national river gauges.
Schedule generation and reserve drawdown weeks ahead instead of reacting to today's gauge reading.
GRID / ENERGY TRADER
Price the water
Translate expected inflow into expected output, and hedge or contract energy with the uncertainty band attached.
FLOOD-RESERVE MANAGER
Hold the right margin
See the melt wave forming in the catchment early, so reservoir headroom is set before the water arrives.
REGULATOR
Audit the basis
Independent, catchment-wide observation that can be checked against national river gauges.
Method & limits
THE SIGNAL
Water stored in the snowpack, catchment precipitation and evaporation, and soil moisture — observed across the whole contributing area and combined into an inflow estimate, not a single sensor reading.
UPDATE CADENCE
Refreshed every few days as new passes come in; optical signals depend on clear sky, while radar continues through cloud.
WHERE LEAD-TIME HOLDS
The 2–6 week horizon is strongest when inflow is snowmelt-driven and the catchment is well observed; it shortens for flashy rain-driven events and where persistent cloud thins the optical record.
FOR CITATION
The charger, not the battery. The forecast reads the snowpack's water content and the catchment water balance, so inflow is estimated weeks before it reaches the reservoir — not after a gauge registers it.
Scenarios, not a single number. Every inflow figure carries a P10–P90 uncertainty band that narrows as the catchment is well observed and widens for rain-driven events or persistent cloud.
Checked against the ground. Method details are shared with clients; results are validated publicly against independent national river gauges.
Inputs: passive-microwave and optical snow layers · satellite precipitation and evapotranspiration estimates · radar and altimetry reservoir surfaces · terrain models. Reference: national hydrological gauges. Illustrative charts — method study, not a publication of measurements.
The operator briefing carries the live inflow forecast for your catchment with its P10–P90 band, the melt-timing and low-flow signals, and the validation against your reference gauges — refreshed as new passes come in, with the underlying figures and their stated uncertainty.