Reassessment of water nuisance standards, HDSR

Introduction

For De Stichtse Rijnlanden Water Board, HydroLogic used d-HyDAMO (Python) to build a fully automated D-HYDRO model of the entire management area from GIS data, and used it to carry out the assessment against the water nuisance standards.

  • Duration: 2023–present
  • Client: De Stichtse Rijnlanden Water Board (HDSR)
  • Keywords: water nuisance, climate adaptation, automated model building, stochast analysis, modelling as a service
  • Models & Tools: D-HYDRO, MODFLOW-MetaSWAP, D-HyDAMO, HYDROLIB-CORE, Python, Water-SchadeSchatter

Background

Need for insight

HDSR must periodically assess whether its water system meets the statutory standards for water nuisance and wants to know at which locations bottlenecks occur, including the uncertainty in those results. In addition, HDSR would like a well-founded comparison of measures, such as adjusted pump stop levels and improved control, to determine what HDSR can best focus on to reduce future water nuisance.

Method

Flood models

For the project, rainfall-runoff / hydrodynamic models with a flood grid were produced in an automated way:

  • MODFLOW-MetaSWAP for rainfall-runoff in rural areas
  • D-HYDRO for hydrodynamics and rainfall-runoff in urban areas
  • RTC in D-HYDRO for the control of structures, including complex area regulations and pump stops

With d-HyDAMO, the D-HYDRO model was built in a fully automated way in Python from HDSR’s management register. Using the stochast method, thousands of combinations of rainfall, wind and external water levels were then calculated in the cloud. Based on the model results, water level statistics and inundation maps were derived, which mapped out the water challenge and bottlenecks per water level area. A BOWA analysis quantified the uncertainty in this water challenge. Scenarios were then calculated with both measures that are likely to increase the water challenge (for example, the construction of water infiltration systems or higher water levels) and possible solution directions such as adjusted control. For these scenarios, the effect on the water challenge was analysed.

The result

Reliable information

HDSR has a single model that can be kept up to date automatically for the entire management area, and a clear, spatial picture of the water challenge, including the uncertainty. The water board can maintain and deploy the assessment toolkit itself and, through the scenario analyses, has insight into which measures reduce water nuisance most effectively.

What did the project deliver?

  • An automated D-HYDRO/MODFLOW-MetaSWAP model for the entire management area of HDSR
  • Approximately 1,500 water level areas assessed against the water nuisance standards
  • More than 2,000 stochast simulations calculated for the water level statistics
  • A complete BOWA run to quantify the uncertainty in the water challenge
“With HDSR, we have developed a model instrument that provides insight into bottlenecks, uncertainties and the effectiveness of measures. This enables the water board to make carefully substantiated choices for a future-proof water system. Thanks to the extensive automation, the focus was on what really adds value: hydrological craftsmanship and reliable results.”
Janneke de Graaf | project lead
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