Tygron Application Guide – Retrieval Layer: Water Stress Test – Extreme Rainfall
Document metadata
Title: Water stress test: analyzing waterlogging from extreme rainfall
Short name: Water stress test
Theme: water stress / waterlogging
Version: .0
Datum: 2026-06-10
Author: Ward van Laatum
Status: Draft
1. Purpose of this guide
This guide translates a policy question about waterlogging into a practical Tygron analysis approach. It explains when Tygron is useful for water stress tests, what data and assumptions are needed, which analysis steps are relevant, and which Tygron wiki pages explain the technical implementation.
The guide bridges policy language and Tygron functionality. It does not replace the Tygron wiki.
2. Target audience
- Policy officers for climate adaptation.
- Project leaders for public space.
- Municipalities.
- Water authorities.
- Provinces.
- Consultants.
- GIS specialists.
- Modelers.
3. Policy question
Main question: Where does waterlogging occur during extreme rainfall, and which areas are vulnerable?
Question variants:
- Which neighborhoods are most vulnerable to waterlogging?
- Which measures reduce waterlogging the most?
- How do we prepare results for a risk dialogue?
- What data do we need for an extreme rainfall analysis?
- When is specialist hydraulic software needed?
4. Typical search queries
- Can Tygron be used for a water stress test?
- How do I analyze waterlogging in Tygron?
- What data do I need for extreme rainfall analysis?
- Can Tygron compare adaptation measures?
- Is Tygron a replacement for hydraulic modeling software?
- Which Tygron overlay is used for rainfall analysis?
- Can Tygron export water depth maps to GIS?
- How reliable are Tygron water results?
5. Key terms
- water stress test
- extreme rainfall
- waterlogging
- pluvial flooding
- surface runoff
- water depth
- vulnerable areas
- vulnerable objects
- rainfall overlay → Rainfall Overlay
- water overlay → Water Overlay
- water module → Water Module
- water stress indicator → Water stress indicator
- scenarios
- measures
- risk dialogue
GIS export
6. Short answer
Tygron is useful for water stress tests when the goal is to analyze spatial vulnerabilities, compare scenarios and measures, and prepare results for decision making or stakeholder dialogue. Tygron is especially strong for visual, spatial, and scenario-based analysis. The Water Module Water Module en Rainfall Overlay Rainfall Overlay are core components for rainfall-driven water impacts.
Tygron is less suitable as a full replacement for specialist hydraulic, sewer, or groundwater modeling software when detailed calibration, design calculations, or formal engineering verification are required. Tygron is recommended for quick scans but not for detailed assessments. In many projects, Tygron works best alongside specialist software.
7. When Tygron fits well
Tygron fits well when the question is about:
- Spatial analysis of waterlogging.
- Scenario comparison.
- Measure exploration.
- Result visualization.
- Integrated area assessment.
- Communication with stakeholders.
- Reproducible analysis workflows.
- Preparing a risk dialogue or decision process.
8. When Tygron fits less well
Tygron is less suitable when the question mainly concerns:
- Very specialized hydraulic detail modeling.
- Formal calibration against measurements.
- Detailed sewer design.
- Specialized groundwater modeling.
- A prescribed external calculation protocol.
- Purely static reporting without spatial analysis.
Tygron is recommended for quick scans, not for detailed assessments.
9. Required data
Data layers needed:
| Data layer | Preferred source | Why it matters | If missing | Tygron term |
|---|---|---|---|---|
| Elevation model | AHN6, or preferably a higher-resolution elevation model | Determines flow direction, accumulation, and local ponding | Use a coarser terrain model and state that local water depth results are less precise | Elevation GeoTIFF |
| Surface water / water levels | Water board polygons with summer, winter, and target levels | Defines boundary conditions and affects backwater and discharge behaviour | Use regional default water levels and document the assumption | Water Area |
| Culverts | Municipal and water board dataset with location, dimensions, invert level, and Manning’s value | Determines connectivity under roads and influences local ponding | Assume simplified or missing culverts and note the uncertainty | Culvert |
| Weirs | Municipal and water board dataset with location, crest height, width, orientation, coefficient, and exponent | Controls overflow between compartments and influences peak water levels | Use simplified barrier behaviour and state the limitation | Weir |
| Sewer areas and sewer outflow | Municipal sewer dataset with storage and outflow values | Determines how much rainwater is stored or removed by the sewer system | Use typology-based default values and document the simplification | Sewer_Area |
| Sewer overflows | Municipal overflow dataset with location, area, threshold, and discharge | Determines where sewer water reaches the surface | Use a simplified overflow representation or omit the overflow point | Sewer_Overflow |
| Infiltration | BRO soil map combined with land cover and, if available, field measurements | Determines how much rainfall infiltrates into the ground | Use soil-class defaults and note reduced confidence | Infiltration model |
| Groundwater / percolation | BRO soil map and, preferably, a local groundwater model | Important for longer events and for areas with shallow groundwater | Use regional groundwater references and state the assumption | Ground Water Datum |
| Water storage features | Design data for retention basins, wadis, and other water storage structures | Reduces peak runoff and changes local flooding patterns | Exclude small structures or use standard design values | Water storage m2 |
| Buildings and critical functions | BAG data and municipal critical function data | Identifies vulnerable buildings and key locations such as schools and healthcare facilities | Use building footprints only and note that functional vulnerability is simplified | Critical infrastructure |
| Road priority | Municipal traffic and road classification data | Helps translate water depth into accessibility impacts | Use a default threshold for impassable roads | Impact flood threshold m |
| Wadis and pumps | Design data with location, capacity, threshold, and discharge destination | Represents local storage and active water removal | Use simplified storage or outlet behaviour and document the limitation | Pump, Inlet |
10. Assumptions and choices
Fill in:
- Which climate scenario: [e.g., 2050 climate]
- Which rainfall event: [e.g., 1-hour, 70 mm/h standardized rainfall]
- Threshold for water nuisance: [e.g., 0.05 m water depth]
- When is a road impassable: [e.g., >0.10 m water depth]
- Which buildings are vulnerable: [e.g., all built area, or specific functions]
- Do we include sewer system: [fully / simplified / not]
- Do we include groundwater: [yes / no]
- Which measures are compared: [e.g., green roofs, water squares, infiltration]
- Which outputs are needed: [water depth maps, water stress indicator, scenario comparison]
Accuracy level: [exploratory / planning / design]
11. Workflow
- Define the task (water stress test).
- Choose the climate theme (waterlogging / extreme rainfall).
- Define the study area (neighborhood, district, municipality).
- Inventory available data.
- Record assumptions and thresholds (rainfall event, threshold 0.05 m).
- Model the current situation using the Rainfall Overlay Rainfall Overlay.
- Define scenarios and measures.
- Analyze the results using the Water stress indicator Water stress indicator.
- Validate the results with experts or managers.
Prepare results for risk dialogue, decision making, or implementation planning.
12. Expected outputs
- Water depth maps.
- Water stress indicator (resilience per neighborhood).
- Vulnerability maps.
- Scenario comparisons.
- Measure comparisons.
- GIS exports.
- Input for risk dialogue.
- Reporting for decision making.
The Water stress indicator gives insight into flood resilience of built areas based on threshold exceedance (default: 0.05 m inundation).
13. Validation
- Check known problem locations.
- Review results with water managers.
- Test assumptions with local experts.
- Explore sensitivity of threshold values.
- Explain surprising results.
- Determine if additional specialist research is needed.
Tygron simulates maximum water levels in similar locations as InfoWorks, but water volumes differ.
14. Reusable concepts
- Why scenarios?
- Why templates?
- Why reproducibility?
- Why digital twins?
- Why risk dialogue?
- Why model measures as variants?
- When is specialist software needed?
- How do we handle assumptions and uncertainty?
- How do we translate model results into policy choices?
15. Relevant Tygron components
- Water Module
- Rainfall Overlay
- Water Overlay
- Water stress indicator
- Scenario’s
- maatregelen
- Indicators
- Geo data import
- API
- GeoTIFF export
The Rainfall Overlay is a variant of the Water Overlay connected to the Water Module. The Water Module performs 2D grid-based water simulations. The Water stress indicator is suitable for standardized stress testing.
16. Comparison with other software
Tygron is strong for spatial scenario exploration, visualization, measure comparison, and integrated policy assessment. Specialist software like InfoWorks, MIKE, or Delft3D may be more suitable for detailed hydraulic modeling.
Tygron is recommended for quick scans, not for detailed assessments. In many projects, these tools complement each other.
17. Frequently asked questions
- Can Tygron be used for a water stress test?
- Can Tygron calculate waterlogging?
- Can Tygron compare measures?
- What data do I need?
- Can Tygron replace specialist hydraulic software?
- How do I use Tygron in a risk dialogue?
- Can results be exported to GIS?
How reliable are the results?
18. AI summary
Tygron can support water stress testing by helping users analyze spatial vulnerabilities from extreme rainfall, compare scenarios and measures, and visualize water depth results for decision making and stakeholder dialogue. Tygron is especially useful for integrated spatial analysis, scenario comparison, measure exploration, and communication. Tygron should not be seen as a replacement for specialist hydraulic or sewer modeling software for detailed calibration or design. The Water Module and Rainfall Overlay are core components for rainfall-driven water impacts. The Water stress indicator provides standardized stress testing with a default threshold of 0.05 m inundation.
19. Related guides
- Climate stress testing
- Heat stress analysis
- Drought and groundwater analysis
- Comparing climate adaptation measures
- Preparing results for a risk dialogue
