1D Pits: Difference between revisions
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Width_or_Dia: Sets the width of the pit inlet section in the vertical plane. <br>
Height_or_WF: Sets the height of the pit inlet channel in the vertical plane.
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Width_or_Dia: Sets the diameter of the pit inlet cross-section in the vertical plane.<br>
Height_or_WF: Not used.
|| [[File:003 Circular pit inlet dimensions.jpg|
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| [[File:Gully pit.jpg|thumb|none|300px|Grate (London, UK)]]
|| Grates, also known as Gully Pits, are common in the United Kingdom and are generally a square grate on top of a circular chamber and a riser outlet. The outlet will then feed into a larger culvert that forms part of the larger urban drainage network.<br><br>
Width_or_Dia: Sets the width of the pit inlet section in the vertical plane. The width is the total
* Case 1 - a gully pit may include all sides of the pit.
* Case 2 - an on grade pit may only include one side.<br>
Height_or_WF: Not used.<br>
|| [[File:006 CASE 1 Gully pit dimensions.jpg|
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== UK Water Industry Research (UKWIR) Inlet Capture Tool ==
In 2023, the UK Water Industry Research (UKWIR) Limited released the Modelling Sewer Inlet Capacity Restrictions Report <u>[https://ukwir.org/modelling-sewer-inlet-capacity-restrictions Modelling Sewer Inlet Capacity Restrictions Report]</u>. The main aim was to develop a sewer modelling methodology to enable the representation of inlet inflow restrictions, focusing on the development of a new 1D model approach to provide more accurate model sewer flooding predictions. The new modelling approach has been devised by combining the findings from a literature review and the development of semi-empirical relationships from academic studies which investigated factors affecting inlet capacity. The new approach allows for 2 types of gully response reflecting 2 flow conditions: Subcritical flow on a shallow road gradient and Supercritical flow on a steep road gradients. A threshold of 0.02 is used to distinguish between shallow and steep road gradients. The reported equations can be used for the production of input inlet curves for TUFLOW 1D pit inlet modelling.
A template for the generation of the UKWIR Inlet Curve can be downloaded from [https://downloads.tuflow.com/Other/Inlet_Spreadsheets/Inlet%20Curve%20Capture%20tool%20v4.xlsx here]. The template determines both Subcritical Head-Discharge and Supercritical Head-Discharge relationships obtained from the Modelling Sewer Inlet Capacity Restrictions Report based on user input values of water depth (in metres). Two sets of curves can be generated, curves based on default parameters, and those based on user-defined parameters. Note, the report is not clear what inlet capacity cap should be applied, so these are not applied within the spreadsheet currently. However, the user can edit the resulting Head-Discharge relationship to apply a required cap on the inlet capacity.▼
▲A template for the generation of the UKWIR Inlet Curve can be downloaded from <u>[https://downloads.tuflow.com/Other/Inlet_Spreadsheets/Inlet%20Curve%20Capture%20tool%20v4.xlsx here]</u>. The template determines both Subcritical Head-Discharge and Supercritical Head-Discharge relationships obtained from the Modelling Sewer Inlet Capacity Restrictions Report based on user input values of water depth (in metres). Two sets of curves can be generated, curves based on default parameters, and those based on user-defined parameters. Note, the report is not clear what inlet capacity cap should be applied, so these are not applied within the spreadsheet currently. However, the user can edit the resulting Head-Discharge relationship to apply a required cap on the inlet capacity.
=TUFLOW Model Inputs=
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</ol>
An example model including Pits is available for download: <u>https://wiki.tuflow.com/index.php?title=TUFLOW_Example_Models</u>
==Pit Search Distance==
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The order of the "Pit Search Distance" command is important as it can be repeated multiple times with different values that are assigned to the 1d_nwke(s) below the ''Pit Search Distance'' command. The pit search command should be included above the the GIS layer containing the pits.
To check if the ''Pit Search Distance'' is working as expected, import the <u>[[Check_Files_1d_nwk_C | *_nwk_C_check]]</u> file to visually see if the pits are automatically connecting to a culvert. The image below is an example of the *_nwk_C_check file and the connections TUFLOW has made to each pit. <br>
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Any further questions please email TUFLOW support: <u>[mailto:support@tuflow.com?Subject=TUFLOW%201D%20pits%20help support@tuflow.com]</u>
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