calgarylens
live record51.0447°N · 114.0719°Walt 1045 m
file 01topic · water7 figuresengagement →claims register →
last updated · 2026.04

Calgary water,
measured against its own ceilings.

Public data on Calgary’s water system, drawn directly from the City of Calgary and its open-data portal. Each figure on this page cites its publisher and any transformation we applied; the JSON behind every chart is committed to the public repository. For the specific public claims being made about these figures — and our responses to them — see the claims register.

water · case filepeak demand · observed
698
ML/day
2025-06-09 — about 73% of plant capacity. Even at peak the plants have headroom; the 2024 Bearspaw rupture showed the feeder main, not capacity, is the system's actual fragility.(/water/daily)
Bow summer flow vs 1912–1941
-28%
30-year means at WSC gauge 05BH004 — early (30 yrs) vs recent (30 yrs). Annual mean has shifted -7%; the summer (Jul–Sep) season — when demand peaks — has dropped further.(/water/bow-flow)
plant capacity · daily
950ML/day
Bearspaw 550 + Glenmore 400 post-upgrade. Binding daily ceiling — annual headroom doesn't help on the worst day.(/water/daily)
residential · 2024
47%
Of total system water — including non-revenue water. Residential is the single largest end use; ICI, regional, and municipal split the remainder of the revenue 78%.(/water/demand#sector-shares)
water loss program · 2027–2030
51%
$179.4M of the $353.9M Plan budget goes to the Accelerated Water Loss Program (pipe replacement, leak detection, cathodic protection).(/water/budget)
[05]

Bow River discharge, 1912–2024

Mean discharge of the Bow River at the Calgary gauge (ECCC station 05BH004), 1912–2024. Thin lines are individual years; thick lines are 10-year rolling means. Summer (Jul/Aug/Sep) is when the river runs lowest and demand runs highest — that’s the stress window the operational cap is designed for. Recent years like 2023 (summer mean 72 m³/s) have been notably low.

Summer discharge — the window when Calgary’s demand peaks and the river runs lowest — has trended notably low in recent years (2023 ran 72 m³/s). Annual mean = simple average of the year’s twelve monthly means · summer = mean of July/August/September · Water Survey of Canada gauge 05BH004 (Calgary), continuous record from 1912.