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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! C
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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
* 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|alt=|left|thumb|300x300px|Case 1 - Grate with dimensions]][[File:006 CASE 2 Gully pit dimensions.jpg|alt=|left|thumb|300x300px|Case 2 - Grate with dimensions]]
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== Brisbane City Council==
The pit inlet curve examples below originate from Brisbane City Council 8000 series standard drawings: <u>https://www.brisbane.qld.gov.au/planning-building/planning-guidelines-tools/planning-guidelines/standard-drawings</u> <br>
[[File: BCC_BSD-8077.JPG|border|700px]]
[[File: BCC_BSD-8051.JPG|border|700px]]<br>
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== South Australian Road Stormwater Drainage Inlets: Hydraulic Study (University of South Australia)==
The Urban Water Resources Centre (UWRC) at the University of South Australia conducted a comprehensive set of hydraulic studies, examining performance of the most common roads’ stormwater drainage inlets in use in South Australia. The study was carried out using the Centre's unique full-scale road surface drainage test rig. Links to the pipe inlets curves are provided in the following link and sections below: <u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/ Hydraulic Study (University of South Australia)]</u>
=== Transport South Australia ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/transport-sa/ Transport South Australia Pit Inlet Curves]</u>
=== City of Adelaide ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-adelaide/ City of Adelaide Pit Inlet Curves]</u>
=== City of Campbelltown ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-campbeltown/ City of Campbelltown Pit Inlet Curves]</u>
=== City of Charles Sturt ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-charles-sturt/ City of Charles Sturt Pit Inlet Curves]</u>
=== City of Onkaparinga ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-onkaparinga/ City of Onkaparinga Pit Inlet Curves]</u>
=== City of Playford ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-playford/ City of Playford Pit Inlet Curves]</u>
=== City of Port Adelaide / Enfield ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-port-adelaideenfield/ City of Port Adelaide / Enfield Pit Inlet Curves]</u>
=== City of Marion ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-marion/ City of Marion Pit Inlet Curves]</u>
=== City of Mitcham ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-mitcham/ City of Mitcham Pit Inlet Curves]</u>
=== City of Salisbury ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-salisbury/ City of Salisbury Pit Inlet Curves]</u>
=== City of Tea Tree Gully ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-tea-tree-gully/ City of Tea Tree Gully Pit Inlet Curves]</u>
=== City of West Torrens ===
<u>[https://www.unisa.edu.au/research/sustainable-infrastructure-and-resource-management/australian-flow-management-group/stormwater-drainage-hydraulic-study/city-of-west-torrens/ City of West Torrens Pit Inlet Curves]</u>
== Spacing of Road Gullies (UK standards: BS EN 124 and BS7903) ==
The following section describes the <u>[https://www.standardsforhighways.co.uk/tses/attachments/a869ed8e-4470-4286-aef4-7d11af24a597 Spacing of Road Gullies]</u> guidance (UK standards: '''BS EN 124''' and '''BS 7903''') which provides a method for determining road gulley capture rates.
The method depends on the following '''Hydraulic parameters:'''
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* Cross-fall, ''S<sub>c</sub>'' (also expressed as a fraction).
* Manning’s roughness coefficient, ''n''. Usually ''n'' = 0.017 for a conventional road surface. Other values are given in the following '''Table 1'''. (For more details, please see Section: 5, Table 5.3N of the <u>[https://www.standardsforhighways.co.uk/tses/attachments/a869ed8e-4470-4286-aef4-7d11af24a597 guidance]</u>).
'''Table 1:''' Values of Manning's ''n''
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'''Calculation of Gully Flow Capture Rates based on Equations'''
<br>The equations given in Appendix C (p.g: 25) of the <u>[https://www.standardsforhighways.co.uk/tses/attachments/a869ed8e-4470-4286-aef4-7d11af24a597 guidance]</u> can be used to determine flow capture rates at different depths, to determine the depth-discharge curve for use within TUFLOW. The method requires the calculations of the flow capacity of the kerb channel and flow collection efficiency of the gully grate.
*As a first step, a gully grate type: P, Q, R, S or T should be selected. The selection of the grating type will determine the design value ''G<sub>d</sub>'' (grating parameter) from '''Table 2'''. (For more details, please see Table A.2, Appendix A of the <u>[https://www.standardsforhighways.co.uk/tses/attachments/a869ed8e-4470-4286-aef4-7d11af24a597 guidance]</u>).
'''Table 2:''' Determination of grating type ''G<sub>d</sub>''
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*Further, a Water Depth against the kerb ''H'' (m) range should be provided. (Please note: The depth range can be changed, but the following equations that are used to calculate the flow capacity are only valid up to the kerb height).
*With the above parameters, the calculations of the i) Flow width (''B'' in m), ii) Cross-sectional area (''A<sub>f</sub>'' in m2), iii) Hydraulic radius (''R'' in m), iv) Flow rate (''Q'' in m3/s) and v) Flow collection efficiency (''ŋ'' (%)) based on the Equations C.1-C.5 which are presented in Appendix C of the <u>[https://www.standardsforhighways.co.uk/tses/attachments/a869ed8e-4470-4286-aef4-7d11af24a597 guidance]</u> can be completed.
*Finally, the resulting depth-discharge data can be used in the TUFLOW pit inlet curves.<br>
The Gully Flow Capture Rates template <u>[https://downloads.tuflow.com/Other/Inlet_Spreadsheets/Gully%20Flow%20Capture%20Rates_v3.xlsx here
'''Key assumption'''<br>'''Note:''' This method assumes that the route the flow takes around the trap limits the discharge from the gully pot to 10 l/s. This limit is effective in both directions, so any negative head on the gully would create -10 l/s flow back up through the gully and flood onto the road. <br>
== 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>
<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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