1D Water Level Tool (HEC‑RAS‑like)

Manual — how to use this tool

On page load, a sample river is loaded and solved automatically so you can see plots immediately.
Change Q, boundary condition, coefficients — the model updates automatically.
Flow regime control: Subcritical → downstream boundary; Supercritical → upstream boundary; Mixed → both upstream + downstream boundaries.
If the interface looks too small/large, adjust UI zoom in the input panel.
To build your own river:
- Click Clear geometry.
- Click + Add cross section → enter River Station + Number of Points.
- Paste two Excel columns (Station, Elevation) into the points table (click first cell → Ctrl+V).
- Add more cross sections and repeat.
- Optional: Import a CSV file (XS_Name, RiverStation, x, z) using the CSV import section.
Click Download results CSV to export computed W.S. elevations.

Tip: If your River Station decreases downstream (common in HEC‑RAS), keep the default convention in the input panel.

Hydraulic inputs

Discharge Q (m³/s)

Flow regime

River station convention

Boundary condition

Boundary W.S. Elev (m) For subcritical, this is the downstream stage boundary.

Gravity g (m/s²)

Energy loss coefficients

Contraction coeff.

Expansion coeff.

Solver controls

Stage tolerance (m)

Max search above thalweg (m)

Geometry (Excel‑friendly)

Paste from Excel: click first cell → Ctrl+V

Import geometry from CSV (optional)

Geometry CSV Required columns: XS_Name, RiverStation, x, z. Optional: LeftBankX, RightBankX, n_LOB, n_CH, n_ROB, L_CH, L_LOB, L_ROB.

Points editor mode

Cross section

Cross section properties

XS Name

River Station (m)

Left bank station (x)

Right bank station (x)

Manning n (optional composite: LOB / CH / ROB)

n LOB

n CH

n ROB

Reach lengths to next downstream XS (optional)

L CH (m)

L LOB (m)

L ROB (m)

Cross section points

Number of points (rows)

#	Station (x)	Elevation (z)

Paste tip: Excel uses tab‑separated columns. Pasting two columns will fill Station and Elevation automatically.

Longitudinal profile

Results

XS	RS	Thalweg	W.S.	Depth@Thalweg	Area	Top width	V	Fr	K	α	Sf

Cross‑section viewer

Blue = water (HEC‑RAS style)

Select cross section

W.S.

—

Depth

—

Validation vs HEC‑RAS (optional) — upload CSV output table and compare W.S. elevations

Station match tolerance (m)

HEC‑RAS CSV file

—

MAE (m)

—

RMSE (m)

—

Max |Δ| (m)

—

HEC‑RAS CSV must include columns for River Station and W.S. Elev (names can vary — the tool will try to auto-detect).

🌊 1D Water Level Tool (HEC‑RAS‑like Standard Step)