Crowdfunding: Native QGIS Tools for Hydrology

31/07/2026

For years, QGIS users have relied on external toolsets from processing providers such as SAGA, GRASS, WhiteboxTools and PCRaster for hydrological analysis. These tools are powerful, but they also introduce challenges: installation issues, inconsistencies across operating systems and versions, and workflows that break when dependencies change. With QGIS 4.4 on the horizon, it's time to bring essential hydrological capabilities natively into QGIS core. Tools from processing providers will still be important for advanced workflows.

Together with Nyall Dawson (North Road), we have defined a clear, minimal, and highly useful set of hydrological tools that will allow QGIS users to perform interpolation of groundwater levels, stream extraction, drainage basin delineation, and catchment analysis without relying on external providers.

To make this happen, QWAST is opening a small crowdfunding effort to cover development costs. If you benefit from hydrological workflows in QGIS, your contribution will directly enable these tools to land in QGIS 4.4, which will be released on 30 October 2026.

Why This Matters

Hydrological workflows are foundational for:

groundwater modelling
catchment management
environmental impact studies
flood risk assessment
geomorphological research
teaching and training in GIS & hydrology

Right now, these workflows depend heavily on third-party processing providers. A native QGIS toolset ensures long‑term stability, improved calculation times, cross‑platform reliability, and seamless integration with the Processing Toolbox, Model Designer and PyQGIS.

This crowdfunding effort directly supports the development of atomic, efficient, and well‑integrated QGIS algorithms that reproduce the widely used SAGA stream and catchment delineation workflow, without external dependencies.

What Will Be Developed

These tools are based on the SAGA implementations but rewritten and optimized for QGIS. The Fill Sinks (Wang & Liu) tool was already implemented in QGIS 3.44 and is a nice example of porting SAGA tools to QGIS core.

We will implement the following tools:

1. Thin Plate Spline Interpolation

Port of the SAGA Thin Plate Spline tool that is important for interpolation of groundwater data.

2. Channel Network & Drainage Tools

Extracted from SAGA's Channel Network and Drainage Basins tool and split into efficient standalone algorithms for extracting channels with their Strahler orders:

Flow direction from DEM
Strahler order from DEM
Strahler order from DEM + flow direction
Channels / Drainage Basins / Junctions from DEM
Channels from DEM + flow direction + Strahler order

3. Upslope Area Tools

Port of SAGA's upslope area algorithm for catchment delineation of a specified outlet, exposed as two QGIS-native tools:

Upslope area (from point), similar to the original implementation where the catchment is delineated for a specified coordinate
Upslope area (from layer), calculates combined catchments for multiple points in a point vector layer

River with styled with interpolated line renderer using Strahler orders

Total Funding Goal

To implement these tools, an amount of €6000 is needed. This covers the full development effort to bring these tools into QGIS core.

How You Can Support

If you or your organization rely on hydrological workflows in QGIS, please consider contributing. Even small contributions help! QWAST will make a first contribution of €2000 and will top up this amount if the crowdfunding goal is not reached before the end of the crowd funding on 1 September 2026.

Donate here

Crowdfunding Progress

€ raised of €

Throught blog posts, I will keep contributors updated on development progress, testing builds, and integration into QGIS 4.4.

Why Crowdfunding?

Several people in the community have already expressed interest in contributing financially. Crowdfunding allows us to:

share the cost across the community
accelerate development
ensure these tools land in QGIS core rather than remaining external
strengthen QGIS's long-term hydrological capabilities

This is a practical, community-driven way to support open-source GIS development.