DS Stilling Basin – Water Level & Rating Curve

Irregular cross-section (channel + floodplain) with Manning flow. Goal-seek water level for each discharge, build rating table (Q, WL, h, Fr, v) and fit a power trend line like in your Excel sheet.

Irregular XS Manning + goal seek Rating curve & trend line Export XLSX / PDF / PNG

1. Cross-section & Hydraulics

Enter XS points, roughness and slope. You can work in SI (m) or US (ft). Rating discharges are always in m³/s like your Excel summary sheet.

Units & roughness
Cross-section (station–elevation)
One point per line: station elevation or station, elevation. You can paste directly from Excel (two columns).
WL(masl) = base level + depth h(m). For the sample, 3050.45 reproduces your Excel WL values.
Single discharge check
Design discharges for rating curve
Each line: SN, Q or Q (SN optional). Q is always in m³/s.

2. Single-Q Result & Rating Table

Q (m³/s) –
WL (masl) –
h (m) –
v (m/s) –
Fr –

Depth h is measured from the lowest point of the cross-section. WL(masl) = base level + h. Velocity and Froude are computed using the wetted area and hydraulic depth at the solved water level.

0 rows Rating table (like Excel summary sheet)
# SN Discharge Q (m³/s) WL (masl) h (m) Fr v (m/s)
For the sample loaded from your Excel, this table should match your CALCULATION OF WATER LEVEL sheet: same WL, depth h, Fr and v for Q = 13…96 m³/s.

3. Cross-section Sketch

Quick visual check of the geometry and solved water surface. Not to scale, but useful to verify that banks and water level look reasonable.

4. Rating Curve & Power Trend Line

Depth h vs discharge Q with a power-law fit h = a·Qb and coefficient of determination R², like in your Excel chart.

Generate the rating table to see the fitted trend line equation and R².