SUEWS Tutorial: Irrigation, Green Spaces & Thermal Comfort

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Hi everyone,

The idea here is to develop a tutorial on how to use the SUEWS plugin to integrate irrigation of different types of green spaces into an urban project.

Main objective

The main aim of this tutorial is to produce an urban energy balance that accounts, as accurately as possible, the effects of irrigation and, consequently, vegetation evapotranspiration. This energy balance can then be used directly or as input for other tools, including SOLWEIG.

The SUEWS–SOLWEIG coupling can then be used to estimate mean radiant temperature (Tmrt) and thermal comfort indices such as UTCI and PET for irrigated urban projects.

These thermal comfort indicators are ultimately what elected representatives and decision-makers need to assess the benefits of different urban design strategies. They can also provide useful arguments for supporting the development of green spaces and the implementation of irrigation during periods of thermal stress.

Target SUEWS version

To be confirmed : I am currently using SUEWS 2026.1.28rc, while @sunt05 previously referred to SUEWS 2026.6.5 so probably it is better to use this last version.

Tutorial scope

The tutorial would aim to cover the following workflow:

  • Setting up an urban project in SUEWS
  • Representing different types of green spaces
  • Integrating irrigation into the SUEWS model
  • Defining different irrigation scenarios
  • Assessing the impact of irrigation on the urban energy balance and evapotranspiration
  • Coupling SUEWS with SOLWEIG
  • Assessing Tmrt and thermal comfort indices (UTCI and PET)
  • Comparing irrigated and non-irrigated scenarios

Case study

The tutorial will be based on a real case study: a ZAC (a French urban development project) in Paris, which my internship company is currently working on. The project covers approximately 7 hectares.

The initial objective of this work was to investigate whether greywater reuse (from showers, washing machines and washbasins) could provide a water source for irrigation and contribute to mitigating the Urban Heat Island (UHI) effect.

For the case study, we are initially considering the reuse of greywater from one building, which can accommodate up to 320 inhabitants. Based on French data, I estimated the potential greywater production at approximately 85 L/day/person. Considering losses, transport constraints and the mismatch between water production and irrigation demand, I assumed that only 50% of this volume could realistically be used for irrigation.

This results in an estimated 13.6 m³ of reusable greywater per day.

Based on our assumptions for subsurface irrigation, this volume could provide irrigation for approximately 1,870 m² of green space during summer.

To investigate how different types of vegetation respond to irrigation, we are considering three hypothetical green-space configurations:

  • Grass only
  • Grass + shrubs/low-growing vegetation
  • Grass + trees

The idea is therefore to use this real-world case study as a basis for developing a reproducible workflow that could also be applied to other urban projects.

I would be very interested in your feedback on this scope and, in particular, on the best way to represent the different irrigation and vegetation configurations in SUEWS.

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I have already prepared, with free Claude AI, a first draft of the tutorial in English, based on the issues and questions I encountered while working on the case study.

For example, I initially found it somewhat challenging to determine whether the plugin expected rasters to contain relative or absolute heights. In the case of the CDSM, absolute height refers to ground level plus tree height, whereas relative height refers only to tree height, with a value of 0 where there is no vegetation.

Similarly, I was a little confused for a while by the UMEP toolbar at the top and by using UMEP through the Processing Toolbox, as I initially thought they were essentially the same thing. I therefore added this information as I came across these issues, in order to help prevent others from encountering the same minor difficulties.

I would be happy to share it here as a starting point. However, I would not consider the technical details to be validated yet. Some of the field names, parameters and workflow steps may need to be corrected or updated, especially given the difference between the SUEWS versions mentioned above.

SUEWS_Tutorial_EN_v1.pdf (4.2 MB)

SUEWS_Tutorial.md (40.7 KB)

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Thanks @Dreywen, and welcome back. This is exactly the thread I hoped for: a clear scope, a real case, and a draft that records the problems you actually hit. The raster pitfalls and the two silent failures you documented are the parts most tutorials leave out.

Target 2026.6.5. Several field names and the water-use forcing convention have changed since 2026.1.28, so I will pin the tutorial to that release and handle the migration.

As offered in the July thread, I will take it from here: I will work through your v0 against the current code and post a revised draft in this thread for you to check against your workflow, with the technical claims verified and the version stated. You keep the direction and the Paris case.

Two framing points I will build in, so you know where it is going. The QGIS and UMEP steps (rasters, morphology, the SOLWEIG run) are UMEP’s domain and will be written as a walk-through that defers to the UMEP manual rather than as SUEWS behaviour. And SUEWS has no shrub class, so the “grass + shrubs” case will be stated explicitly as an approximation.

Nothing more needed from you for now. Once the revised draft is up, your reading of it against the real workflow is what matters most.

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