AR-Tarseem
DEM-to-hydrograph watershed modelling: delineation, special delineation points with reservoir storage routing (modified Puls), SCS-CN/UH design hydrographs (CN from a raster or a single constant value), custom return periods, spatially-variable rainfall via Thiessen stations, four SCS storm types + custom hyetographs, adjustable Ia/S, ARF, Muskingum & Muskingum-Cunge routing, HEC-HMS .basin/.met/.pdata export. Pure NumPy + GDAL.
Copyright (C) 2026 Ahmed M. Raslan, PhD & Amr R. Refaiy, PhD -
Water Engineering Experts. Released under the GNU General Public
License v3.0 or later (GPL-3.0-or-later).
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AR-Tarseem is a complete DEM-to-hydrograph watershed modelling tool.
From a metric DEM and a pour-points layer it produces:
- Streams, Catchments, Longest Flow Paths (three Tc estimates),
optional sub-basins / sub-LFPs / reaches / junctions.
- Special Delineation Points: enforce junctions at dam locations
(snapped to the main flow path), split sub-catchments at the
points only or combined with the area-based subdivision, and
define any point as a Reservoir with modified-Puls storage
routing (elevation-volume curve + spillway/orifice structures,
or a storage-discharge table) - with inflow, outflow,
attenuation, storage and stage outputs.
- Design-storm hydrographs per catchment / sub-basin / junction /
reach: CSVs + interactive HTML charts, with an editable output
window so every hydrograph is complete (recession to zero).
- Curve Number from a raster (auto-aligned to the DEM) or a single
constant value; adjustable lambda = Ia/S (0.01-0.5).
- Rainfall: all four SCS/NRCS 24-h distributions or a custom
hyetograph CSV; custom return periods; Thiessen station
weighting; TRRL-UK / Riyadh / fixed Areal Reduction Factors.
- Reach routing: Lag, Muskingum, and variable-parameter
Muskingum-Cunge on a trapezoidal channel.
- HEC-HMS interchange: .basin (with true Reservoir elements),
per-return-period .met files, and a .pdata carrying the
reservoir Elevation-Storage tables (HEC-HMS 4.7-4.13 / WMS).
- Automatic QML styling. Uses ONLY libraries that ship with QGIS:
numpy, osgeo (GDAL), QGIS API.
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The plugin can also write its network as an AR-Awdiya project file
(.json) for further interactive network editing and reporting.