Calculator Inputs
Enter geometry and allowances. The tool returns single-chamber, usable, and total adjusted volume in multiple units.
Example Data Table
Sample inputs show how allowances and factors influence totals.
| Length | Width | Depth | Freeboard | Sediment | Fill % | Chambers | Safety | Outcome |
|---|---|---|---|---|---|---|---|---|
| 110 m | 12 m | 4.5 m | 0.5 m | 0.2 m | 100% | 1 | 1.00 | Baseline operating volume |
| 110 m | 12 m | 4.5 m | 0.5 m | 0.2 m | 90% | 1 | 1.10 | Lower usable fill with margin |
| 360 ft | 40 ft | 15 ft | 2 ft | 0.5 ft | 100% | 2 | 1.05 | Two chambers with contingency |
Formula Used
The calculator treats the lock chamber as a rectangular prism. First, it adjusts depth using allowances:
Effective Depth = Operating Depth + Freeboard − Sediment Allowance
Then it computes volume:
Single Chamber Volume = Length × Width × Effective Depth
Usable volume applies the fill percentage, and total volume applies the number of chambers and safety factor:
Total Adjusted Volume = Single Volume × Fill% × Chambers × Safety Factor
How to Use This Calculator
- Select your unit system and enter the chamber length and width.
- Enter operating water depth, then add freeboard if needed.
- Include sediment allowance to represent depth loss over time.
- Set fill percentage for partial operations or staged filling.
- Add number of chambers and a safety factor for planning margin.
- Press Calculate Volume to view results above the form.
- Use the download buttons to export CSV or PDF reports.
Practical Notes on Lock Chamber Volume Planning
A concise technical overview to support design checks, operations, and reporting.
1) What the volume represents
Lock chamber volume is the water held inside the usable prism bounded by the inside length, clear width, and effective depth. For planning, this volume approximates the water exchanged during a lockage cycle, supporting intake sizing, pump selection, and water supply forecasting. The calculator reports both single-chamber and total adjusted volumes.
2) Depth allowances and sediment impacts
Effective depth is computed as operating depth plus freeboard minus sediment allowance. Even a small sediment layer can materially reduce capacity in long chambers. For example, a 0.20 m depth loss across a 110 m by 12 m chamber reduces geometric volume by about 264 m³ (110 × 12 × 0.20), which is 264,000 L.
3) Fill percentage and operational scenarios
Fill percentage models partial filling, staged commissioning, or restricted operations. A 90% fill factor reduces usable volume linearly while preserving geometry for comparison. Use it to evaluate seasonal constraints, water conservation targets, or temporary work windows when full depth is not maintained.
4) Multiple chambers and contingency factors
Twin locks and parallel chambers scale volume with the chamber count. The safety factor adds a controlled margin for uncertainty, surge allowances, or conservative planning. Typical preliminary contingencies range from 1.02 to 1.15, depending on measurement confidence and operational variability.
5) Reporting, conversions, and QA checks
The tool outputs m³, ft³, liters, and US gallons to support mixed-unit projects and procurement. A quick QA check is dimensional: doubling length should double volume; reducing effective depth by 10% should reduce volume by 10%. Exported CSV/PDF summaries help document assumptions for reviews and audits.
FAQs
1) Does this include gate recesses, culverts, or rounded corners?
No. It uses a rectangular prism model based on clear inside dimensions and effective depth. Subtract recesses or add corrections if your lock geometry departs from a simple rectangle.
2) How should I choose the sediment allowance?
Use recent bathymetry or maintenance records. If data is limited, set an allowance reflecting expected siltation between dredging cycles and re-check sensitivity with multiple values.
3) What does the fill percentage represent?
It models partial filling or restricted depth operation. It scales the usable volume linearly, making it useful for temporary conditions, staged commissioning, or water conservation scenarios.
4) When should I apply a safety factor?
Apply it when you need a planning margin for uncertainty, operational variability, or conservative budgeting. Keep it close to 1.00 for measured geometry and increase only with justification.
5) Can I enter feet and still get metric results?
Yes. Select feet as the unit system and enter all dimensions in feet. Results are reported in both metric and imperial volumetric units for cross-checking.
6) Why is the effective depth larger than operating depth?
If you add freeboard, effective depth increases to represent additional water above the operating depth. If sediment allowance is larger than freeboard, effective depth decreases accordingly.
7) How do I verify the numbers quickly?
Perform a spot check: compute Length × Width × Effective Depth manually. Then apply fill percentage, chamber count, and safety factor. The totals should match within rounding.