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{|class="wikitable"
|-
! Inlet Type !! Example !! Description !! Dimensioned Example
|-
! Q
| [[File:Q pit inlet.jpg|thumb|none|300px|Depth-Discharge Pit or Channel]] || width="300pt"|Depth-Discharge Pit or Channel, pit inlet inflow information is defined within TUFLOW via a user -defined Pit Inlet Database and associated pit inlet curves. This approach allows for unlimited flexibility. Any pit design or configuration can be incorporated into a TUFLOW model if the inlet depth-discharge relationship is known. || <u>[[1D_Pits#TUFLOW_Model_Inputs | See TUFLOW Model Inputs]]</u>
|-
! R
| [[File:Side_Entry_pit.jpg|thumb|none|300px|Kerb Inlet]]|| width="300pt"|Kerb inlets, also know as side entry pits or lintels are common in Australia. The pit chamber can vary depending on overall depth, length and the addition of any haunched riser units.
|| Kerb inlets, also known as side entry pits or lintels, are common in Australia. The pit chamber can vary depending on overall depth, length, and the addition of any haunched riser units.<br><br>
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.
|| [[File:003 Side Entry pit dimensions.jpg|alt=|left|thumb|300x300px|Kerb Inlet with dimensions]]
|-
! C
| [[File:Circular pit inlet.jpg|thumb|none|300px|Circular Pit Inlet]]|| width="300pt"|Circular pit inlet
|| Circular pit inlet.<br><br>
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|alt=|left|thumb|300x300px|Circular Pit Inlet with dimensions]]
|-
! W
| [[File:Gully pit.jpg|thumb|none|300px|Grate (London, UK)]]
| [[File:Gully pit.jpg|thumb|none|300px|Grate (London, UK)]] || width="300pt"|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 width in the direction of flow to the pit. For example:<br>
* 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>
 
== PageSpacing Underof ConstructionRoad Gullies (SectionUK standards: SpacingBS ofEN Road124 Gulliesand 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.
== Spacing of Road Gullies (UK adoption BS EN 124 and BS7903) ==
The following section describes the method to determine the spacing of road gratings, according to the [https://new.sthelens.gov.uk/media/330117/5126_ha-102_00.pdf/ Spacing of Road Gullies] guidance ('''BS EN 124''' and '''BS 7903''').
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: 4.35, Table 15.3N of the <u>[https://newwww.sthelensstandardsforhighways.govco.uk/mediatses/330117attachments/5126_haa869ed8e-102_00.pdf/4470-4286-aef4-7d11af24a597 guidance]</u>).
 
'''Table 1:''' Values of Manning's ''n''
<br>[[File:Table1Table1N.jpg|450px750px|]]<br>
 
* The grating type (P, Q, R, S or T), or the size and angle of kerb inlet.
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<br>[[File:Figures 1 2.jpg|850px|]]<br>
 
'''B) Calculation of Gully SpacingsFlow Capture Rates based on Equations'''▼
 
<br>Alternatively, theThe equations given in SectionsAppendix 5C (p.g: 25) of the <u>[https://newwww.sthelensstandardsforhighways.govco.uk/mediatses/330117attachments/5126_haa869ed8e-102_00.pdf/4470-4286-aef4-7d11af24a597 guidance]</u> can be used forto thedetermine Spacingflow ofcapture Roadrates Gulliesat different depths, directlyto determine the depth-discharge curve for use within TUFLOW. The method requires the calculations of the Flowflow capacity of the kerb channel and Flowflow collection efficiency of the gully gratinggrate. ▼
'''A) Use of Tables for determining the flow capacity of gullies and maximum spacings for gully gratings'''<br>
*As a first step, a gully grate type: P, Q, R, S or T should be selected. The selection of the grating Typetype will determine the design value ''G<sub>d</sub>'' (grating parameter) from '''Table 2'''. (For more details, please see AnnexTable A.2, Appendix BA of the <u>[https://newwww.sthelensstandardsforhighways.govco.uk/mediatses/330117attachments/5126_haa869ed8e-102_00.pdf/4470-4286-aef4-7d11af24a597 guidance]</u>).▼
Equations given in Section 5 of the [https://new.sthelens.gov.uk/media/330117/5126_ha-102_00.pdf/ guidance] are used for the calculation of the Spacing of Road Gullies. Design tables have been compiled to present a quick design approach. Tables can be found in Annex C.
Annex C includes design tables for the grating types: Types P, Q, R, S and T. The Design Tables C2-C6 in Annex C of the [https://new.sthelens.gov.uk/media/330117/5126_ha-102_00.pdf/ guidance] present the area that can be drained for an intermediate gully and a range of crossfall and gradient of flow widths. For the design tables a rainfall intensity of 50mm/h and Manning’s ''n'' = 0.017 are considered.
 
For ease of access, Tables C2-C6 are replicated in the Spacing of Road Gullies file here [Excel File]. Please see, tabs: Type P, Type Q, Type R, Type S and Type T. The Excel file provides tables like the following examples and their corresponding graphs.
<br>[[File:Tables C2-C6 of Annex C.jpg|950px|]]<br>
 
<br>'''Note:''' a) ''Tables C2 to C6 are for intermediate gullies on a uniform gradient and are not strictly accurate for gradients which vary greatly over short distances.''
b)''The Excel tables also present the flow collection efficiency η of the grating in % (in brackets)''. <br>
 
▲'''B) Calculation of Gully Spacings based on Equations'''
▲<br>Alternatively, the equations given in Sections 5 of the [https://new.sthelens.gov.uk/media/330117/5126_ha-102_00.pdf/ guidance] can be used for the Spacing of Road Gullies, directly. The method requires the calculations of the Flow capacity of the kerb channel and Flow collection efficiency of the gully grating.
▲*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 Annex B of the [https://new.sthelens.gov.uk/media/330117/5126_ha-102_00.pdf/ guidance]).
 
'''Table 2:''' Determination of grating type ''G<sub>d</sub>''
<br>[[File:Determination of grating type.jpg|650px|]]<br>
 
'''Note:''' ''According to the manual: The value of G<sub>d</sub> should be used to calculate the maximum spacing between gullies.''
 
*Road (longitudinal) gradient (''S<sub>L</sub>''), Crossfall (''S<sub>c</sub>'') and Manning's (''n'') should then be determined. Parameter values can be obtained from '''Table 3'''.
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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) The Flow width (''B'' in m), ii) the 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 6C.1-10C.5 which are presented in SectionAppendix 5C of the <u>[https://newwww.sthelensstandardsforhighways.govco.uk/mediatses/330117attachments/5126_haa869ed8e-102_00.pdf/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 SpacingGully ofFlow RoadCapture GulliesRates Exceltemplate file<u>[https://downloads.tuflow.com/Other/Inlet_Spreadsheets/Gully%20Flow%20Capture%20Rates_v3.xlsx abovehere]</u>, includes a calculation tab which can be used for the completion of the above calculation processprocesses. Based on calculations and Equations (11)C.6 and (12)C.7 of the <u>[https://newwww.sthelensstandardsforhighways.govco.uk/mediatses/330117attachments/5126_haa869ed8e-102_00.pdf/4470-4286-aef4-7d11af24a597 guidance]</u> the maximum allowable spacings forupstream gullyof gratingthe gully can be further calculated (For more details, please see Appendix C, p.g: 25).
 
'''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 number of 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.▼
 
▲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.
== How to Translate On-Grade Approach Flow / Pit Capture Flow Curves to Depth / Discharge Curves for use in TUFLOW ==
Manning's equation calculations can be used to convert on-grade approach flow information to a water depth at the pit. After manually calculating the depth to flow relationship the user simply needs to associate these water depth values with the pit capture flow information typically included in on grade pit inlet curve datasets.
 
=TUFLOW Model Inputs=
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<li> Import an empty 1d_nwk GIS file from the TUFLOW file template folder (model\gis\empty).
<li> Digitise points to represent pit locations. The points should be snapped to the start or end of 1d_nwk line features that define the underground pipe network.
<li> Update the field attributes for each Pit point. Refer to 5the <u>[https://docs.12tuflow.2 of the 2016com/classic-hpc/manual/latest/ TUFLOW Manual]</u>. The most commonly used attributes are:
* Type = Q (C, R and W are also options if pit inlets based on structure dimension is required instead of using a Pit Inlet Database approach).
* US_Invert = Used to specify the ground elevation of the pit. If Conn_1D_2D is set to “SXL”, US_Invert is used as the amount by which to lower the 2D cell and the pit channel invert is set to this level.
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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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<br>
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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