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Tools we have developed

One of ISMO’s objectives is to develop modelling and simulation tools to better understand and predict the performance of stormwater solutions under varying conditions. Here we distribute information regarding the tools developed.

ISMO project is continuously developing real-time monitoring. The aim of the project and the research groups at Turku University of Applied Sciences is to develop a holistic real-time environmental observation network to produce reliable and up to date information on changes in the state of the environment.

We will measure surface water temperatures at selected locations on the coastal and inland seas, and water levels in streams where active project work is being carried out. These measurements support coastal and hydrological modelling and research in our research group.

Find out more about real-time monitoring.

For more information on monitoring, please contact Emil Nyman

The ISMO project aims to initiate the development of digital twins for different scale stormwater systems.

There is no single definition of “digital twin” and here it is a digital replicate of a real environment that allows to simulate stormwater-related processes that mimic reality. The ISMO project develops digital twins on three different scales:

Individual decentralized stormwater management structures, e.g. bioretention cells (areas of a few 10s of m2),
Block scale: areas of several 1,000s of m2, including buildings, roads, green spaces and stormwater infrastructure,
Catchment scale: areas of several km2 including all types of urban fabric, engineered drainage infrastructure and natural streams.

The goal of each digital twin is to first reliably simulate hydraulic and hydrologic processes that can be verified against measured data and then be used to test different scenarios. The scenarios to be tested are scale dependent. The digital twin for individual stormwater management structures allows to test and optimize the effect of different soil or other filtration and storage media, while the catchment scale digital twin would allow to test the effect of changing precipitation patterns, e.g. due to climate change, on catchment scale runoff, or the effect of large area landuse changes.

The project focuses on the replication of the physical processes and environmental boundary conditions to obtain simulations results as close to reality as possible but puts less emphasis on the visual replication of reality; i.e. the objective is not to produce photo-realistic visualizations of the simulated environment and simulation results.

As each digital twin requires extensive data for the calibration and validation of simulations, a major objective of the project is to collect relevant data. Data collection includes laboratory tests (e.g. soil type analyses, infiltration measurements, sensor calibrations), field campaigns (e.g. infiltration measurements, base flow measurements, mapping of vegetation states, measurement of surface temperature variations), and continuous, online measurements (e.g. meteorological observations, water level and discharge, water temperature, and conductivity).

Ultimately, the data collected in near-real time should be integrated with the digital twins to allow for hydrologic and hydraulic nowcasting of the pilot catchments.

Explore ISMO’s digital twin

We appreciate all feedback regarding the digital twin. Your feedback will help us to further develop the tool.
Give us feedback.

Further explanations for the first CFD Digital Twin  

Following the link above (Explore ISMO’s digital twin) takes you to an online tool that allows to run 2-dimensional computational fluid dynamic (CFD) simulations for a virtual “bioretention cell” utilizing OpenFOAM code.

The tool should help the non-expert user to evaluate the effect of soil properties on the detention properties of a bioretention cell used to manage stormwater runoff.

The tool is in a beta version and so far, has a fixes size (10 m long, 1 m high or which 0.53 m represent soil and 0.47 m allows for ponding of water). The user can define porosities for three soil layers as well as a constant water inflow rate. It only simulates the movement of water on the surface and through the soil but ignores evaporation, and the effects of temperature and wind on evaporation. There are no other losses of water either except though outflow on the lower right or overflow. This corresponds to a bioretention cell that is lined with an impermeable layer. NOTE: the simulation runs on a server of the Center for Science and at the moment is not able to run several simulations at the same time. That is, if a user changes parameters and starts a new simulation, previous ones will stop. We are working on the apps ability to run multiple simulations in parallel.

In a later development stage, parameters like radiation, temperature and wind will be added as well as the option to modify the geometry of the model (length and depths).

Parameters that can be set by the user are:

Inlet flow rate [m3/s]:

On the left side a constant inflow of water can be set that flows “on top” of the cell, like a rain drain that would discharge on the surface of a bioretention cell. The water is then able to flow on the surface and infiltrate into the soil below. The soil is comprised of three equally spaced individual layers, for each of which a porosity must be set. This could be, for example, to simulate a top layer of topsoil or mulch, a middle layer with lower porosity like coarse sand and a lower drainage layer, e.g. gravel.

The volume of water that enters the simulated structure (from the left) as run on, measured in cubic meters per second [m³/s]. Example: a 1-hour rain with a uniform rain intensity of 10 mm/hr falling on an area of 1,000 m2 smooth tarmac with a minor inclination will generate a peak flow of approx. 2.5 l/s or 0.0025 m3/s.

Switch for water inlet [0=flow-OFF; 1=flow-ON]:

Use this to simulate inflow of water (1) or no inflow (0). Note: when choosing “no inflow” (0) an initial water fraction (below) should be chosen. In this scenario only the emptying of the cell is simulated. If no inflow and no initial water fraction is set, nothing will be simulated. Note: the inflow cannot be switched on/off while a simulation is running.

Porosity (top-, middle-, bottom layer):

Soil porosity refers to the empty spaces, or pores, between soil particles. Like a sponge it has a lot of empty spaces that can hold water when it is dry, but when it is wet, those spaces fill up. Soil porosity affects how water moves through the soil and how much water the soil can hold. If soil has high porosity, it can hold more water and allow it to move through more easily, if it has low porosity, water cannot move as well.

Porosity is expressed as ratio in this application. For example, 50 % porosity is 0.5 here. A value of 1 would be a solid without pores, 0 would be air.

Some examples of soil porosities are given below. Note these are averages, every soil class covers a range of porosities.
Gravel: 0.2-0.4
Sand: 0.3-0.5
Silt: 0.4-0.5
Clay: 0.4-0.6