InfoWorks ICM has the ability to model both urban drainage systems and fluvial systems in an integrated manner. In the past, urban drainage systems would have been modelled in InfoWorks CS and the migration of data from InfoWorks CS to ICM is well documented (http://blog.innovyze.com/2015/07/29/transferring-cs-to-icm/) with virtually all data migrated between the 2 software. This is because InfoWorks ICM has its roots in InfoWorks CS.
This is not the case on the fluvial side, where models exist in our river modelling software, InfoWorks RS. The setup of InfoWorks ICM and InfoWorks RS are a little more distinctive. Most fluvial modelling software use cross-sections and links but they differ in the ways they represent structures and junctions, InfoWorks RS and ICM are no exception to this. Nonetheless it is still possible to migrate network data between InfoWorks RS and ICM with some ease, avoiding the time-consuming re-creation of the entire fluvial model network. Although it should be noted there are some incompatible network objects that exists in InfoWorks RS, these are primarily Routing reaches, Bernoulli Loss Units, Flapped Orifices, Blockage Units and Symmetrical conduits. There are also no junction nodes (although these can be represented in InfoWorks ICM as break nodes) or connectivity links. This means that some of the connectivity requires fixing within InfoWorks ICM. There are also differences in the approach to modelling bridges which is identified later in this article.
The first thing to note, is that with an InfoWorks ICM license, it is possible to open the InfoWorks RS viewer software which allows the user to open, view and export InfoWorks RS model networks. With the InfoWorks RS network open, Right click on the Network with IWRS and click on Export->to CSV… Export the RS Network to CSV with the following options checked:
Figure 1: Export options for InfoWorks RS CSV Export to ICM
Have you wonder where subcatchments can “drain to” in InfoWorks ICM? Probably you are thinking nodes, but the correct answer is more complex giving the flexibility InfoWorks ICM offers you. Let’s have a look:
- Nodes: subcatchments can drain to any node type, except outfalls. For example, subcatchments can discharge runoff to a manhole in sewer systems or to break nodes in river reaches. If manholes have flood type “Inlet” or “Gully”, subcatchments with a system type of ‘storm’, ‘combined’ or ‘overland’ drain to the above ground elements and are subject to the inlet parameters before they can enter the below ground element, whereas subcatchments with ‘foul’, ‘sanitary’ or ‘other’ system types drain directly to the below ground element.
- Links: subcatchments can drain to any link. For conduits, river reaches, channels and bridges the runoff from subcatchments is applied as lateral inflow. For control links, the runoff is applied to the upstream node. If this node is an outfall, the downstream node is selected to drain to, and if both nodes are outfalls the runoff is lost.
- Multiple Links: similar conditions to links, but in this case subcatchments drain to several links according to a weight factor. The weight factor can be user-defined or dependent on the link length.
- Subcatchments: subcatchments can drain to another subcatchment and the runoff generated by the first one is added to the rainfall of the destination one. The runoff is then subject to the initial loss, volume, and routing models of the surfaces of the destination subcatchment.
- 2D zone: subcatchments can also drain to 2D zones if they discharge to a dummy 2D manhole node. A 2D manhole with small volume can be defined as dummy node to make the connection between the subcatchments in the 1D model with the 2D zone in the 2D model. The dummy node needs to be connected to a link, which can be a flap valve in the opposite direction.
InfoNet has the ability to attach an unlimited number of attachments to any of its objects, which are managed through the attachments array (see image below). This post explains how to export the attachments array information using the Open Data Export Centre.
In the Open Data Export Centre it is necessary to map the attachments fields into the output file, see images below. Continue reading
Good news! InfoWorks ICM (version 7.5.2 and newer) now has a built in tutorial to cover all major functions of the software. To access this helpful tool, just open the Help file, click on the ‘Contents’ tab, and you will find the Basic Tutorial under the ‘InfoWorks ICM Tutorials’ section.
Once you locate the tutorial in the Help, you will need to download the corresponding data that will help you work through the tutorial. To retrieve that data, please visit www.innovyze.com/updates and choose InfoWorks ICM from the list of products and login. If you do not know your username and password, please email email@example.com to ask for your credentials so that the support team can provide them to you. Once you are logged in, you will find the data for download: Continue reading
In InfoWorks ICM you can extend model building functionalities with SQL and Ruby scripts. This blog is an example of how to define the nodes to which subcatchments drain using these tools. The scripts presented can be easily adapted to “drain to” links or subcatchments.
If you are modelling subcatchments that cover areas with one node only, you can use a simple SQL script. This is a common situation in urban drainage models, where subcatchments are usually delineated for each node. The SQL script simply sets the node to where the subcatchment drains to the node that it contains, as presented in the next figure.
Figure 1. SQL script to connect subcatchments with the overlay node.
You may have noticed, that in some instances, the Pipe full capacity value on a pipe in InfoWorks ICM is less than the flow in a surcharged pipe. How can there be more flow in a pipe than its full capacity?
The Pipe full capacity (pfc) field is populated when the model network is validated. It is calculated from the Colebrook White or Manning equations. These equations are much more simplistic than the full solution St Venant equations used by the InfoWorks ICM simulation engine used to generate the model results. Therefore, there can sometimes be differences between the pipe full capacity field and the actual flow that can discharge. The value in the pfc field is only intended to be an approximation/reference for the user. It is not used by the engine to determine when a pipe goes into surcharge.
The Colebrook White or Manning equations assume that the pipe is infinitely long and therefore there is often more flow through a pipe than the quoted capacity, without it going into surcharge. To prove this is the case you can make the pipe a longer length or apply a constant max flow and you should see the pipe surcharging. The length of the pipe has a significant effect. You may find that a pipe of say 10 feet can carry much more flow than one of 300 feet, given the same gradient, roughness etc.
This pfc value has been in the software ever since we can remember, certainly since the early days of HydroWorks. It can be a useful reference, but sometimes creates confusion. We hope that this blog post provides some clarity on how the pfc field was intended to be used.
Figure 1: Area Take Off Dialogue Box
The Area Take Off option allows automatic calculation of runoff surface areas and the contributing areas of subcatchments using data imported from a Geographic Information System. It is designed to extract the areas surfaces form a catchment according to their types (Roads, Buildings and Permeable surfaces) and to the systems where they are connected (Storm, Sanitary/Foul etc.).
The Area Take-off tool in InfoWorks ICM provides a number of user definable operations. Some operations are complex and can lead to accidental misuse if they are not fully understood. One such case is the “Proportional system type split” option (shown in Figure 1), which is responsible for dividing up any areas that are left over after the primary areas have been extracted from the subcatchment by the Area Take-off operation. The complexity arises when there is no area of a specific type to be taken off from a subcatchment. According to the Area Take Off technical note within the InfoWorks ICM help section (3.4 & 4), in such cases, no residual area will be contributing to the runoff generation process. Therefore, it is recommended that you don’t select the “Proportional system type split” option when you are not simultaneously extracting the different types of contributing areas (Roads, Buildings and Permeable surfaces) for the various system types (Storm, Sanitary/Foul etc.) in your model network.
A common engineering practice is to take off a defined layer (say, buildings) and to divide the rest of the catchment areas across the other surface types (i.e. Roads and Permeable surfaces). In such circumstances, if a subcatchment does not present any building surfaces, but does include roads and permeable surfaces, then performing area take-off on the building layer, while leaving the “Proportional system type split” option active, will generate a null total contributing area. This in turn will lead to erroneous simulation results. Therefore, deactivating the “Proportional system type split” option is preferable in such situations, leaving the user to manually define the system type and the surface number to obtain the right overall contributing area count and distribution.
Fireflows are an integral part of the Hydraulic modeling process and provide a means to calibrate your model. Fireflow represents the amount of water available in a network for fire protection purposes apart from the amount of water used in the network demand. You may use the InfoWater Fireflow module to analyze your existing hydrants or provide recommendations for future build-outs.
In InfoWater, there are three inputs that can be applied while conducting a standard Fireflow. Continue reading
Float valves are one valve type available to use within the InfoWater, H2ONET or H2OMAP Water software that may not be as widely used as more common valve types such as a Pressure Reducing Valves (PRVs) or a Flow Control Valves (FCVs). Because Float Valves are not used as much, users may not be aware of the full functionality of this type of valve or how this type of valve works. This blog post will explain the functionality of the valve and provide a few suggestions on how users can make use of this valve within their models .
First let’s start with a description of the Float Valve from the software help file as this gives a good explanation of what these valves represent:
Float Valves: – Many storage tanks and reservoirs are fitted with float valves (e.g., ball float valves) on the inlet pipe to control rate of flow and prevent overflow. These valves gradually close (increase the resistance of the inlet pipe) as the water level in the controlling tank rises. The headloss across the valve is modeled (via a curve) based on any user specified pairs of headloss vs. flow points. The valve is active if the water level in the controlling tank is below the lower control level or the water level is between the lower and upper levels after the valve opening. Likewise, the valve is closed if the water level in the controlling tank is at or above the upper control level or the water level is between the lower and upper after the valve closes.
ICM RiskMaster allows 2D hydraulic results from InfoWorks ICM to be combined with economic data to allow damages to be quantified.
Traditionally flood management policies have been based upon the design standard philosophy, where policy makers decide on an appropriate protection level to be achieved within the flood system which is used to design and manage hydraulic infrastructure. In contrast with this approach and following the guidelines specified in the EU Floods Directive 2007/60/EC on the assessment and management of flood risks, flood management policies based on risk rather than system performance have been developed in recent years. Flood risk management policies are based on the evaluation of the consequences generated by flooding events and the alleviation measures on the expected flood impacts over a given time period.
Risk-based analysis methods can be used in order to assess and manage hydraulic infrastructure which protects assets from flood events. A flood-risk methodology analyses a hydraulic system based on the evaluation of the consequences derived from the service of the hydraulic infrastructure rather than system performance. Thus, in contrast with traditional performance methods, in which the hydraulic system is expected to service a specific loading level, a flood risk approach should take into account all type of events based on their probability of occurrence. The results of the analysis provide a comprehensive view of the performance of the hydraulic system and the consequences derived from flood events.
The calculation of risk involves multiplying the damage result for each receptor in a simulation with the probability of occurrence of the event simulated. The total damages are calculated at each damage receptor by taking the 2D flow depth and using the depth-damage curve to associate this with a damage value. This is then summed for all damage receptors to provide a total damage value for each return period. This in turn is multiplied by the event probability, to provide the annual damage. Continue reading