Inputs
Example Data Table
Sample scenario using the thickness method for a sediment basin.
| Time | Area | Initial depth | Current depth | Volume | Rate | Thickness rate |
|---|---|---|---|---|---|---|
| 30 days | 500 m² | 3.0 m | 2.7 m | 150 m³ | 5.000 m³/day | 10.000 mm/day |
| 14 days | 320 m² | 2.5 m | 2.42 m | 25.6 m³ | 1.829 m³/day | 5.714 mm/day |
Formula Used
- Silt thickness (Δh) = max(0, hinitial − hcurrent)
- Silt volume (Vs) = Δh × A
- Capacity loss (Vs) = max(0, Vinitial − Vcurrent)
- Volume rate (Rv) = Vs / t
- Equivalent thickness = Vs / A (when area is provided)
- Thickness rate (Rh) = (Vs / A) / t
- Mass (M) = Vs × ρ (bulk density)
- Mass rate (Rm) = Rv × ρ
All inputs are converted internally to SI units for consistent calculations, then presented as standard field-friendly outputs.
How to Use This Calculator
- Select the method that matches your measurements or survey records.
- Enter the time elapsed between inspections or survey dates.
- Provide plan area to obtain thickness and thickness rate results.
- For thickness method, enter initial and current depth values.
- For capacity method, enter initial and current storage volumes.
- For direct method, enter the measured deposited sediment volume.
- Optionally add bulk density to estimate mass and mass rate.
- Press Calculate to view results, then export CSV or PDF.
Professional Article
1) Purpose of siltation tracking
Siltation is the gradual buildup of fine sediment in basins, channels, sumps, and temporary excavations. Tracking the rate helps teams protect storage capacity, maintain flow paths, and plan cleaning before performance drops. A measured rate also supports transparent reporting during earthworks and water-control activities.
2) Common construction locations
Typical hotspots include sediment basins, perimeter drains, culverts, detention ponds, cofferdams, and dewatering sumps. High-intensity rainfall, exposed subgrade, and poor upstream controls accelerate deposition. Establishing a consistent survey section or reference grid improves repeatability across inspections.
3) Field inputs that improve accuracy
Use a fixed plan area (measured from drawings or GPS), consistent depth points, and a defined inspection interval. If you have haul tickets or dredging logs, the direct volume method is practical. Bulk density is optional, but it allows mass-based comparison between sites and seasons.
4) Selecting the best method
The depth-change method is ideal when you can measure initial and current depths at the same locations. The capacity-loss method fits ponds and basins where storage is surveyed or calculated. The direct volume method is best after removal, when deposited volume is already known.
5) Worked example with data
Assume a basin plan area of 500 m². Depth reduced from 3.0 m to 2.7 m over 30 days. Thickness Δh = 0.30 m, so silted volume Vs = 0.30 × 500 = 150 m³. Volume rate = 150/30 = 5.0 m³/day. Thickness rate = 0.30/30 = 10 mm/day. With density 1600 kg/m³, mass rate ≈ 8,000 kg/day.
6) Interpreting results for decisions
Volume rate is useful for estimating disposal and equipment time. Thickness rate highlights whether upstream erosion controls are improving. Capacity loss percent quickly communicates risk to project stakeholders. When an allowable thickness is defined, the “days to allowable” output helps schedule cleaning proactively.
7) Maintenance planning and budgeting
Combine the calculated daily rate with weather forecasts and planned disturbances (grading, trenching, haul roads). If a basin historically accumulates 5 m³/day, a two-week intensive phase can add ~70 m³. Use that estimate to plan haulage, access, and temporary stockpile space.
8) Reporting and documentation
For audits and environmental monitoring, record dates, methods, and units used. Keep photos of gauge marks or survey points, and export the CSV/PDF report for consistent documentation. Over time, trend the rate before and after control improvements to demonstrate measurable performance gains.
FAQs
1) What is a good inspection interval?
Use the shortest interval that matches site risk. After major rain or heavy earthworks, inspect within 24–48 hours. Otherwise, weekly checks are common for active drainage controls.
2) Why does thickness sometimes show as dashes?
Thickness outputs need plan area. If area is missing, the calculator can still report volume and volume rate, but cannot convert volume into an equivalent depth.
3) Should I use wet or dry density?
Use bulk density that reflects how sediment is handled on site. For wet dredged material, wet bulk density is more representative. For dried stockpiles, use dry bulk density.
4) What if current depth is larger than initial depth?
The calculator prevents negative deposition by setting thickness and volume to zero when the current depth exceeds the initial depth. Re-check survey points and datum consistency.
5) How do I estimate area for irregular basins?
Use plan drawings, GPS polygon measurement, or a simple length-by-average-width estimate. Keep the method consistent across inspections to make rate comparisons meaningful.
6) Can I use this for channels or trenches?
Yes. Define a representative plan area segment (length × average width) and measure depths at fixed stations. This provides a practical accumulation rate for maintenance planning.
7) How should I present results to stakeholders?
Share volume rate and capacity loss percent for quick risk understanding. Include thickness rate to show trends. Export CSV/PDF and attach photos or survey notes for traceability.
Use results to plan dredging and maintenance budgets confidently.