Dam Seepage & Sliding Stability Calculator – Embankment Dam Design

Dam Seepage & Sliding Stability Calculator

Embankment dam design • Uplift pressure • Exit gradient • Factor of safety • 2D cross‑section • PDF report

🛠️ Parent Hub ERH Master Tools Hub → 💧 Hydraulic Hub Hydraulic Engineering Hub →

🎓 100-Day Hydro Mastery Free course → 🛠️ 100+ Tools Hub Explore → 🔗 LinkedIn Connect with Engr. Rokib

📐 1. Seepage & Sliding Stability – Why It Matters

Embankment dams must be stable against seepage (internal erosion) and sliding (external stability). This calculator uses Darcy's law for seepage (simplified flow net), uplift pressure under the dam, and sliding factor of safety (FoS) based on weight, base friction, and water pressure. It also computes the exit gradient at the downstream toe to check piping risk.

Seepage (unit width): q = k·h·(N_f/N_d)
Uplift force: U = (γ_w·h·B)/2 (triangular distribution)
Sliding FoS: FoS = (W·tanφ + c·B) / (P_w + lateral forces)
Exit gradient: i_exit = Δh / ΔL (should be < critical gradient 0.8–1.0)

🚀 2. Live Dam Stability Calculator

Dam height H (m)

Base width B (m)

Upstream water depth h_u (m)

Downstream water depth h_d (m)

Soil cohesion c (kPa)

Soil friction angle φ (deg)

Unit weight of dam material γ (kN/m³)

Seepage coefficient k (m/s) – for flow estimate

Batch CSV (H, B, h_u, h_d, c, phi)

Get PDF Report via Email

CSV Template

📊 3. Dam Cross‑Section & Seepage Path

📈 4. Factor of Safety vs. Water Level & History

📘 5. How to Use the Calculator

1. Enter dam geometry (height H, base width B), upstream and downstream water levels.
2. Provide soil properties: cohesion c, friction angle φ, unit weight γ.
3. Optional: seepage coefficient k for flow rate estimate.
4. Click "Compute Stability" – sliding FoS, uplift pressure, exit gradient, and seepage flow are calculated.
5. 2D cross‑section shows dam profile, water levels, and uplift distribution.
6. Batch CSV: upload multiple designs; output table with FoS and exit gradient.
7. PDF report includes the dam sketch and all parameters.

❓ Frequently Asked Questions

❓ What is a safe sliding factor of safety?

For embankment dams, FoS ≥ 1.5 is required for normal loading, ≥1.2 for seismic. This calculator uses FoS > 1.5 as "safe".

❓ What is exit gradient and why is it important?

Exit gradient at the downstream toe indicates piping risk. If exit gradient exceeds critical gradient (≈0.8–1.0), internal erosion may occur. The calculator shows a warning if unsafe.

❓ Can I use this for concrete dams?

This tool is for embankment (earth/rockfill) dams. For concrete gravity dams, uplift distribution is different; however, the sliding formulation is similar.

🌐 Standards & References

USACE EM 1110-2-1901 (Seepage) | USBR Design Standards for Embankment Dams | Dam Safety Guidelines (ICOLD)

WhatsApp 📧 Email

© ERH Dam Stability Calculator – Based on simplified flow net and limit equilibrium. All data processed locally.