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).
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.
The plugin can also write its network as an AR-Awdiya project file (.json) for further interactive network editing and reporting.