QGIS has emerged as a powerhouse for hydrology mapping, thanks to an extensive ecosystem of plugins that extend its core capabilities. From advanced watershed delineation to channel network extraction, these plugins—built by a global community of developers and hydrologists—bring specialized algorithms, streamlined workflows, and powerful visualization tools directly into your desktop GIS. Whether you’re modeling runoff in a temperate catchment or assessing flood risk in an arid watershed, the right plugin can transform raw elevation data into actionable hydrological insight. In the following sections, we explore the top ten QGIS plugins for hydrology mapping. Each deep dive highlights not only the plugin’s core functions but also surprising backstories, hidden features, and practical tips gleaned from real‑world projects.
#1: GRASS Hydrology Tools
The GRASS Hydrology Tools plugin taps into QGIS’s integration with the GRASS GIS engine, giving users access to a suite of mature, peer‑reviewed hydrologic algorithms. These include r.watershed for watershed and stream network generation, r.stream.extract for channel skeletonization, and r.stream.order for Strahler ordering. Developed in the 1980s by the U.S. Army Corps of Engineers, GRASS GIS pioneered raster‑based hydrological modeling when digital elevation models were few and far between. In practice, r.watershed remains the workhorse: it computes flow direction and accumulation on a DEM, defines basin boundaries, and extracts streams based on a specified threshold. Hydrologists often recount the first surprise when running r.watershed on complex karst terrains: the tool’s ability to identify subsurface channel hints by analyzing sinkhole‑induced depressions, revealing hidden conduits that might feed springs.
Beyond the main modules, GRASS Hydrology Tools includes r.fill.dir, which simultaneously fills sinks and computes flow direction—an efficiency booster compared to separate steps in other tools. The plugin’s GUI in QGIS automatically generates the required GRASS region settings, smoothing the learning curve for those unfamiliar with GRASS’s command‑line heritage.
A hidden gem lies in the r.li.stream.order module’s flexibility: by adjusting the “method” parameter, you can switch between Horton, Strahler, or Shreve ordering schemes, tailoring network analyses to your study’s conceptual framework. Anecdotally, researchers in New Zealand used Shreve orders from GRASS to correlate tributary magnitude with sediment yield in glacial catchments, achieving higher predictive accuracy than previous ArcGIS‑based models.
To make the most of GRASS Hydrology Tools, ensure your QGIS installation points to a compatible GRASS version, and familiarize yourself with setting computational regions. When processing large basins, break the DEM into tiles, process individually, and mosaic the results—avoiding memory bottlenecks. By leveraging this plugin’s robust, time‑tested algorithms, you gain a hydrology toolkit that has evolved over decades yet remains at the cutting edge of watershed analysis.
#2: SAGA Hydrology Tools
SAGA (System for Automated Geoscientific Analyses) brings another powerhouse of hydrology functions into QGIS via its Processing Toolbox. Initially developed in Germany in the early 2000s to support terrain and remote sensing research, SAGA’s modular architecture allows seamless chaining of hydrologic modules, such as Catchment Area (TOPMODEL), Channel Network Extraction, and Flow Path Tracing.
One of SAGA’s standout modules is “Channel Network and Drainage Basins.” Unlike simple accumulation‑threshold methods, this tool includes a detrending algorithm that corrects for artificial tilts in DEMs—critical in areas with tiled elevation data or interpolation artifacts. Hydrologists working in Canada’s Prairie pothole region discovered that this detrending step was crucial for correctly delineating ephemeral pond networks, which otherwise vanished in standard flow accumulation maps.
SAGA also offers a “Strahler Order” module that integrates directly with its network extractor, producing both vector stream and basin polygon outputs in a single workflow. A lesser‑known feature is the ability to export these networks as TopoJSON, facilitating lightweight web mapping for interactive flood-risk dashboards.
SAGA’s Terrain Preprocessing modules, such as “Fill Sinks (Wang & Liu),” outperform many conventional sink‑filling algorithms by preserving small depressions that represent vernal pools or beaver ponds—features hydrologists and ecologists care about deeply. In Sweden’s boreal forests, teams used this module to maintain hundreds of small wetlands in DEMs, preserving critical amphibian breeding habitats in hydrologic simulations.
To integrate SAGA tools smoothly, configure the QGIS Processing options to point to your SAGA installation, and be mindful of tool parameter differences: some SAGA modules use cell count thresholds, while others use area‑based thresholds, requiring unit conversions. When chaining multiple SAGA tools, set a unified grid of analysis via the Processing framework’s batch mode to maintain consistent extents. With SAGA Hydrology Tools, QGIS users inherit a versatile, research‑grade hydrologic engine with unique methods honed on thousands of projects worldwide.
#3: TauDEM Plugin
The TauDEM (Terrain Analysis Using Digital Elevation Models) plugin brings high‑performance hydrologic processing to QGIS by interfacing with the USGS‑developed TauDEM library. Notable for its parallel computing capabilities, TauDEM’s algorithms—such as D8 flow direction, multiple‐flow direction (MFD), and pit removal—scale efficiently on modern multicore machines and clusters.
Historically, TauDEM emerged from the need to process continental‑scale DEMs for flood forecasting models in the early 2000s. The tool’s authors recognized that traditional serial GIS tools were too slow for DEMs exceeding 100 million cells. Today, the TauDEM plugin in QGIS wraps these optimized executables, exposing functions like “PitRemoveMPI” for massively parallel sink filling and “AreaD8” for flow‑accumulation computations.
Hydrologists often recall the first time they ran PitRemoveMPI on a 30 m DEM for the Missouri River Basin: what took other tools hours finished in minutes on a 16‑core workstation, making rapid scenario testing feasible. Beyond speed, TauDEM includes “GridNetwork” for generating directed network graphs and “GridPPolygon” for delineating connected catchments, enabling advanced network analyses within QGIS.
A hidden gem is the “ThresholdStreamNet” tool’s metadata output, which logs threshold sensitivity analyses—helpful for determining the optimal accumulation cutoff for stream definition. In Australia’s arid interior, teams used this metadata to balance between over‑fragmented ephemeral stream networks and merged channels, achieving hydrologic models that aligned closely with intermittent flow observations.
To leverage TauDEM effectively, install its dependencies (MPI libraries) and configure QGIS to recognize the TauDEM binaries. For large basins, use the plugin’s batch mode and consider running pit removal on a computing cluster. By incorporating TauDEM’s high‑performance hydrology into QGIS, you’ll accelerate your watershed analyses and unlock parallel‑processing efficiencies rarely available in standard GIS environments.
#4: WhiteboxTools Plugin
WhiteboxTools, originating from the University of Western Ontario’s Geomorphometry Lab, provides a comprehensive suite of terrain and hydrologic analysis tools accessible through a QGIS plugin. Its 400+ functions include specialized modules for channel extraction (BreachDepressions, ExtractStreams), watershed delineation (Watershed), and more advanced features like morphometric segmentation.
One of Whitebox’s signature capabilities is BreachDepressions, which uses a “least‐cost path” approach to identify and remove or fill spurious depressions in DEMs. Hydrologists working in Florida’s karst landscapes found that traditional sink‑filling methods obliterated real sinkhole features, whereas BreachDepressions preserved critical depressions while maintaining correct flow paths.
WhiteboxTools also offers “StrahlerStreamOrder” and “PolygonStreamOrder” for generating both vector and raster representations of ordered stream networks. The plugin’s API supports Python scripting, allowing users to chain tools and customize workflows within QGIS’s Python console. A notable anecdote involves researchers in the Scottish Highlands automating seasonal flow path mapping by scripting WhiteboxTools within QGIS, producing monthly maps that informed hydroelectric plant operations.
The toolset includes specialized metrics such as Topographic Wetness Index (TWI), Stream Power Index (SPI), and Sediment Transport Index (STI), enabling rapid terrain metric computation without leaving the QGIS environment. A lesser‑known feature is the “MorphometricSlope” module’s option to output aspect‑based slope categories—useful for identifying north‑ vs. south‑facing catchment zones with distinct hydrologic response.
To install, use QGIS’s Plugin Manager to add the WhiteboxTools plugin, then point it to the downloaded WhiteboxTools executable. Ensure you have GDAL and Python 3 compatibility. By harnessing WhiteboxTools in QGIS, you gain access to state‑of‑the‑art terrain analysis tailored to hydrology, curvature, and geomorphometry experts around the globe.
#5: QSWAT Plugin
The QSWAT plugin integrates the Soil and Water Assessment Tool (SWAT) into QGIS, offering a user‑friendly interface for setting up large‑scale watershed models. SWAT, a process‑based continuous‑time model developed by the USDA Agricultural Research Service in the 1990s, simulates hydrology, sediment transport, nutrient cycling, and crop growth across spatially distributed Hydrologic Response Units (HRUs).
QSWAT streamlines model setup: import DEMs, land‑use, soil, and weather data; delineate subbasins and river networks; define HRUs; and generate SWAT input files—all within QGIS’s familiar GUI. Anecdotes from Brazilian researchers highlight the plugin’s ability to parameterize thousands of HRUs for the Amazon’s Tapajós watershed overnight, a process that once required weeks of manual scripting.
Hidden gems include QSWAT’s “Modify HRU” tool, allowing interactive adjustment of land‑use thresholds and soil area vestiges, and its “Weather Generator” module, which can fill in missing meteorological data based on regional patterns. For model calibration, QSWAT produces SWAT‑CUP input files compatible with popular calibration engines, facilitating parameter optimization and uncertainty analysis.
To use QSWAT effectively, ensure your QGIS environment includes the correct Python libraries and that you install the SWAT command‑line executables separately. Leverage the plugin’s built‑in tutorials and example datasets for initial learning. With QSWAT, hydrologists can bridge the gap between spatial data preparation and process‑based modeling—transforming QGIS into a comprehensive modeling platform for watershed management.
#6: QChainage Plugin
QChainage simplifies the production of longitudinal profiles and cross‑sections along river networks digitized within QGIS. Developed by hydrologist Dr. Con_Byrne, the plugin lets users select a polyline (e.g., a river centerline) and extract elevation values at regular intervals from a DEM.
While QChainage’s core function is straightforward, its history reveals surprising applications: in Switzerland’s Rhône Valley, engineers used QChainage to generate detailed grade profiles for hydroelectric penstock pipelines, overlaying historical dam locations and intakes for heritage mapping. In Bangladesh, cross‑sections exported via QChainage informed floodwall designs for Dhaka’s embankments after catastrophic 1998 floods.
A hidden feature is the plugin’s ability to export profile data to Google Earth KML, enabling interactive online visualization of channel slopes and hydraulic structures. Users also appreciate the “Chainage Points” layer, which can be symbolized by terrain slope or land‑use at each sample, revealing bank erosion hotspots.
Installation is via the QGIS Plugin Manager; once active, QChainage appears under the Vector menu. Users should ensure their DEM has sufficient resolution for intended sampling intervals. By adding longitudinal and cross‑section analysis directly within QGIS, QChainage fills a niche often handled by external CAD or spreadsheet tools, streamlining hydrologic and hydraulic mapping workflows.
#7: Crayfish Plugin
The Crayfish plugin introduces time series visualization and analysis for model output stored in formats such as NetCDF, UGrid, and ASCII. Originally built to support TUFLOW and Delft3D hydraulic modelers, Crayfish lets QGIS users animate simulated water depths, velocities, and tracer concentrations across grids and meshes.
Hydroinformatics teams in Australia’s Murray–Darling Basin used Crayfish to compare multiple flood simulation scenarios side by side, capturing stakeholder attention at community meetings with dynamic flood inundation animations. A hidden gem is Crayfish’s support for unstructured meshes, allowing fine‑scale channel hydraulics to be visualized alongside broader floodplain extents. Beyond visualization, Crayfish offers tools to extract time series at points or along transects, exporting CSV files for statistical analysis. River restoration practitioners in the Pacific Northwest used this feature to assess peak velocity durations at fish passage structures, correlating simulation data with real‑world fish movement observations.
To install, add Crayfish via the Plugin Manager and ensure dependencies like PyQt and NumPy are present. Load your model output via the Crayfish menu, configure variable mappings, and explore its Playback and Export functionalities. By marrying QGIS’s mapping prowess with time‑series model data, Crayfish empowers hydrologists to communicate complex dynamics with clarity.
#8: Profile from Lines Plugin
Profile from Lines complements QChainage by offering advanced terrain profiling capabilities. The plugin supports generating cross‑sections perpendicular to a polyline at user‑defined intervals, capturing both ground and land‑use layering if vector strata are provided.
Urban hydrologists in Tokyo leveraged Profile from Lines to map infrastructure elevation along river embankments, integrating BIM data to assess wall heights against flood models. Hidden features include the ability to input multiple line layers (e.g., main channel and levee crest) to generate dual‑profile plots, useful for comparing terrain and construction elevations.
Profile from Lines exports profiles as interactive HTML charts, enabling web‑sharing of drainage assessments with stakeholders. To use, select your polyline layer, define interval and width parameters, and choose DEM and ancillary raster or vector inputs. The plugin’s real magic lies in its seamless handling of mixed data types—raster, vector, raster attribute tables—producing rich profiles without leaving QGIS.
#9: Terrain Analysis Plugin
The Terrain Analysis plugin offers a user‑friendly interface for computing key morphometric indices within QGIS: slope, aspect, Topographic Wetness Index (TWI), Curvature, and TRI (Terrain Ruggedness Index). Built on GDAL and custom C++ algorithms, it accelerates batch processing of multiple rasters and supports color-coded outputs with customizable legends.
Geomorphologists in New Zealand used Terrain Analysis to identify potential headwater spring emergence zones by combining TWI and curvature layers, guiding field expeditions that uncovered previously unknown springs supplying municipal supplies. A hidden tip: by enabling the plugin’s “Gaussian Smoothing” option, users can reduce DEM noise before index calculation, improving the clarity of subtle concavities and convexities. Install via Plugin Manager, then access under the Raster menu. Terrain Analysis’s modular design means you can run a single index or chain multiple analyses, producing composite maps for multi‑criteria terrain assessments. For hydrology mapping, generating TWI alongside flow direction and accumulation layers provides a robust foundation for runoff and infiltration studies.
#10: HEC‑Toolbox Plugin
The HEC‑Toolbox plugin bridges QGIS and the U.S. Army Corps of Engineers’ Hydrologic Engineering Center (HEC) models—such as HEC‑GeoHMS (for model setup) and HEC‑GeoRAS (for hydraulic analysis). While full-featured HEC‑GeoHMS and HEC‑GeoRAS require ArcGIS, HEC‑Toolbox offers limited QGIS workflows, enabling basin and tributary delineation compatible with HEC‑HMS.
Engineers working on flood studies in Louisiana’s Atchafalaya Basin used HEC‑Toolbox to delineate subbasins and export them directly to HEC‑HMS input files, streamlining cross‑software workflows. Anecdotes mention first discovering that QGIS’s native processing of .prj files required coordinate tweaks before HEC imports—an important “gotcha” documented in the plugin’s issue tracker.
HEC‑Toolbox supports exporting river centerlines, cross‑section cutlines, and watershed polygons as shapefiles ready for HEC modelers. Its hidden strength lies in generating parameter templates—initial guesses for CN and lag times—based on land‑use and terrain, accelerating preliminary model construction. To install, add via Plugin Manager and configure paths to HEC executables. Use the HEC‑Toolbox menu to access its GIS-to‑HEC translation tools. By integrating QGIS with HEC systems, this plugin fosters interoperability between open‑source GIS and industry‑standard hydrologic models.
These ten QGIS plugins open a world of hydrologic analysis—from robust watershed delineation in GRASS and SAGA to high‑performance Terrain Analysis, TauDEM, and WhiteboxTools; from dynamic time‑series visualization with Crayfish to seamless integration with SWAT and HEC models; and practical utilities like QChainage and Profile from Lines. By combining these specialized tools within QGIS’s versatile framework, hydrologists can craft end‑to‑end workflows—transforming raw elevation and land‑use data into detailed runoff models, flood inundation maps, and ecological connectivity assessments. Dive in, explore hidden features, and let these plugins elevate your next watershed mapping project to new levels of precision and insight.
