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. Free software, licensed under the GNU General Public License version 2 or (at your option) any later version. A copy of the licence ships with the plugin in the file LICENSE.
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.
RECOMMENDED COMPANION: download AR-Awdiya, the hydrologic network modelling companion of AR-Tarseem. Opening the exported .basin / .pdata files in AR-Awdiya gives an interactive network editor and lets you generate polished Word and PDF report documents of all the outputs (hydrographs, reservoir routing tables, summaries) for direct use in engineering deliverables.