Reservoir Balance Dashboard¶

Live monitor — instantiates Conserved Reservoir-Flux Balancing

Puts the current level, headroom, and net flow of every reservoir on one live display, so drift and an impending fill-or-drain are seen while there is still time to act.

The Reservoir Balance Dashboard is the state-now view of a stock-flow network: one tile per reservoir showing its current level, how much headroom remains before it fills or empties, and whether it is filling or draining right now. What makes it this mechanism is its tense. The Mass-Balance Table reconciles a period that has ended; the System Dynamics Simulation projects a future that hasn't happened; the dashboard shows the present, refreshed on a cadence, so a human watching it catches slow drift and an approaching limit early enough to intervene. It is deliberately a display, not a trigger — the automated threshold trip is the Capacity Headroom Alert's job. The dashboard is the continuous picture a person reads to keep the whole network in view at a glance.

Example¶

A hospital blood bank runs its inventory as a dashboard, one tile per blood type. Each tile shows units on hand, headroom expressed as days-of-cover against recent demand, the net flow (donations booked in versus transfusions going out), and a shelf-life clock for the oldest units. On a normal morning everything reads green — except O-negative, showing 14 units, cover of about 1.2 days, and a net-flow arrow pointing down.

Nothing has crossed a hard threshold yet, so no alarm has fired. But a charge nurse glancing at the wall sees O-negative draining faster than it is being replaced and starts a targeted donor call-out that afternoon, well before the reservoir approaches empty. The dashboard didn't decide anything; it made a quietly draining reservoir legible, on time, next to every other reservoir competing for attention — which is exactly what a level-only report or an end-of-week reconciliation would have shown too late.

How it works¶

One tile per reservoir. Each renders three things together: level, headroom against capacity, and current net flow direction.
Level and rate, never level alone. A full-looking stock draining fast is the danger a static level hides; the tile pairs the stock with its trend.
A refresh cadence matched to the fastest reservoir. The display updates often enough to catch the quickest-moving stock before it runs out of room.
Read continuously, by a human. Its distinctive mode is the sustained glanceable overview — not a logged period, not a fired alarm.

Tuning parameters¶

Refresh cadence / time step — how often tiles update. Too slow misses a fast drain; too fast turns normal churn into flicker and noise.
Headroom framing — absolute units, days-of-cover, or percent full; days-of-cover travels best across reservoirs of different sizes.
Aggregation level — one tile per raw reservoir versus a rolled-up network total; detail versus overview.
Level-versus-rate emphasis — how prominently the trend arrow sits beside the level.
Smoothing window — raw readings or a moving average; smoothing calms noise but delays the moment a real turn becomes visible.

When it helps, and when it misleads¶

Its strength is early legibility: slow drift and an impending fill-or-drain become visible across the whole network in a single glance, well before a hard limit is hit.

Its failure modes are those of any monitor. A dashboard shows state but does not act, and a reservoir that looks healthy on level can be draining fast on rate — so a level-only tile lulls. The classic misuse is curating the display until it always reads green: once the shown level becomes the number people manage, they optimise the indicator instead of the reservoir, and the monitor stops reflecting reality.^[1] The discipline that guards against this is to pair every tile with its trend and a named owner who is expected to respond to it, so the display drives action rather than reassurance.

How it implements the components¶

The Reservoir Balance Dashboard realises the archetype's live-monitoring surface — the components a continuous display produces:

stock_level_signal — each tile's headline is the current level of its reservoir, read live.
capacity_and_headroom_profile — the gauge showing how full each reservoir is and how much room remains before it fills or empties.
cadence_and_time_step — the refresh interval on which the whole live view is redrawn.

It does NOT compute or reconcile the balance equation — that's the Mass-Balance Table — nor fire the threshold trip (Capacity Headroom Alert), nor project future levels — that's the System Dynamics Simulation.

Instantiates: Conserved Reservoir-Flux Balancing — the dashboard is the operational eyes on the network's stocks.
Sibling mechanisms: Mass-Balance Table · Capacity Headroom Alert · System Dynamics Simulation · Sankey Flow Map · Stock-and-Flow Diagram · Water or Resource Budget · Inventory Reconciliation Workflow

Notes¶

The dashboard and the Capacity Headroom Alert are a matched pair, not competitors: the dashboard is the continuous display a human reads to keep context, while the alert is the automated trip that fires when a level crosses a bound and nobody happens to be looking. A network usually wants both — the display for judgement, the alert for the small hours.

References¶

[1] Goodhart's law — when a measure becomes a target, it ceases to be a good measure. A dashboard level tuned to stay green is a live example: the reservoir's real state and its displayed state quietly diverge. ↩