Lock 4 - Bookpurnong

As of September 9, 2026, Lock 4 - Bookpurnong is filled to 77.3% of its total capacity, holding roughly 23 hm³ of water out of a maximum 29 hm³. At this level the reservoir is within its normal operating range. Of that total, about 21 hm³ is usable (live) storage.

Over the most recent week on record the fill level has held broadly steady (+0.7 pts), and it is 5.0 points above its level on the same date a year earlier.

Across the readings we hold for Lock 4 - Bookpurnong — 1095 data points between September 11, 2023 and September 9, 2026 — the level has ranged from a low of 65.5% (September 18, 2023) to a high of 79.4% (September 11, 2023). On average the reservoir is fullest around September and at its lowest around June.

The dam at Lock 4 - Bookpurnong was completed in 1929. It is operated by BOM primarily for water supply. It lies within the River Murray Basin basin at 34.337°S, 140.577°E.