Subcatchment LIDS Controls Grid (SWMM)
This grid contains a series of records defining the LIDS control structure parameters for the subcatchment, and is displayed by clicking on the 
button located to the right of the LIDS controls field in the Subcatchment properties.
The fields which comprise the grid are described in the following table.
Database Table Name: sw_sub_suds
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Show Columns |
Database Names |
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Size, Type and Units |
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Defaults and Error Limits |
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Field Name |
Help Text |
Database Field |
Size |
Precision |
Default |
Error Lower Limit |
Error Upper Limit |
Warning Lower Limit |
Warning Upper Limit |
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LIDS structure ID |
A name which identifies this particular LIDS structure. | id | Text | 254 |
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LIDS control ID |
The name of the LID control object, which applies to this structure, can be selected from the dropdown list. |
suds_structure | Text | 254 |
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Control type |
A read-only field which displays the type of LIDS control object. | control_type | Text | 254 |
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Area |
The area of the LIDS structure. | area | Double | NA | 3 | 0 | |||||
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Number of units |
The number of LIDS structures of the selected type within this subcatchment. | num_units | Long integer | 1 | 0 | 0 |
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Area of subcatchment |
A read-only field which displays the area of the subcatchment affected by the number of units. This field is automatically updated when the Area or Number of units fields are edited. | area_subcatchment_pct | Double | 3 |
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Unit surface width |
The width of the outflow face of each LIDS structure. This parameter applies to Green roof, Infiltration trench, Permeable pavement, Rooftop disconnection and Vegetative swale that use overland flow to convey surface runoff off from the unit. It is disabled for Bio-retention cell, Rain garden and Rain barrel types of SUDS controls. | unit_surface_width | Double | L | 3 | 0 | 0 |
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Initial saturation |
For Bio-retention cells, Rain gardens, and Green roofs this is the degree to which the unit's soil is initially filled with water (0 % saturation corresponds to the wilting point moisture content, 100 % saturation has the moisture content equal to the porosity). The storage zone beneath the soil zone of the cell is assumed to be completely dry. For other types of SUDS controls, it corresponds to the degree to which their storage zone is initially filled with water. |
initial_saturation_pct | Double | 3 | 0 | 0 | 100 |
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Impervious area treated |
The percent of the impervious portion of the subcatchment's non-LID structure's area whose runoff is treated by the LID practice. (E.g., if rain barrels are used to capture roof runoff and roofs represent 60% of the impervious area, then the impervious area treated is 60%). If the LID unit treats only direct rainfall, such as with a green roof or roof disconnection, then this value should be 0. If the LID structure takes up the entire subcatchment then this field is ignored. | impervious_area_treated_pct | Double | 3 | 0 | 0 | 100 |
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Pervious area treated |
The percent of the pervious portion of the subcatchment's non-LID structure's area whose runoff is treated by the LID practice. | pervious_area_treated_pct | Double | 3 | 0 | 0 | 100 |
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Outflow to |
The outflow from the LID structure can be set to either Outlet, Pervious or Impervious by selecting the appropriate option from the drop-down list. | outflow_to | Text | 15 | Outlet |
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Drain to subcatchment |
The subcatchment to which the selected LID structure is to drain can be selected from a drop-down list. | drain_to_subcatchment | Text | 254 |
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| Drain to node | The node to which the selected LID structure is to drain can be selected from a drop-down list. | drain_to_node | Text | 254 |
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If both the Drain to Subcatchment and Drain to node fields are blank, then the drain flow goes to the outflow specified in the Outflow to field.
