Flow Basin
This field identifies the flow basin where the upstream sewer structure is located. This field may be automatically populated if the flow basins are defined and the Flow Basin Outlets are populated in the Flow Basin Inventory module.
Pipe Shape
This is used to help calculate the Capacity field. It has a pre-defined list of shapes. Although shapes can be added to the list the pre-defined ones cannot be modified. Any shapes added to the list will be calculated as "round" pipes in the Capacity field.
Dia/Height (in)
Enter the diameter of a round pipe in inches. If the pipe is not round, enter the height in inches.
Pipe Width
Enter the Pipe width in inches. This field is only enabled when the Pipe Shape is not round.
Map Page No.
The Map Page Number field is automatically populated from the corresponding field in the Structure Inventory module. This is a read-only field in the Pipe Inventory module.
Length (ft)
The length of the pipe from the center of the upstream manhole to the center of the downstream manhole.
Note: This can be calculated automatically by clicking in the field and pressing F5 if the US Station and DS Station fields are populated on the Construct tab.
Est # of Joints
This field is calculated by (Pipe Sec Length / Length) = Ext # of Joints. This is used in the Sewer Rehab calculations.
Slope %
Slope refers to the vertical displacement along the length of the pipe with respect to the horizontal displacement along the length of the pipe (otherwise known as the rise/run).
If the US Invert and DS Invert on the Elevations Tab and Length field on the Attributes tab are filled out, this field will be autocalculated using the following formula.
[(US Invert - DS Invert) / Length] x 100 = Slope %
If any of these three values do not exist in the record, a slope value can be manually without having to "lock" the slope.
Slope Lock
This box is automatically marked when users manually enter a slope in the Slope field. Leave the checkbox marked to stop the slope from auto-calculating.
Mannings
This refers to a value assigned to a pipe based on its interior roughness. This is used in the calculation of the pipe's capacity.
Capacity (cfs)
Capacity refers to the maximum amount of flow the pipe is capable of holding (in cubic feet per second). Capacity is based on the pipe diameter, Manning's number, and slope. It is calculated by the program using the following equation:
Manning's Equation:
Q= Quantity of flow
A= Cross-sectional area
R= Hydraulic radius (in feet)
S= Slope of the pipe (rise/run)
n= Manning's number
Note: The hydraulic radius is calculated using the following formula: Cross-sectional area (square feet)/perimeter of the pipe (feet). The Manning's number refers to a value assigned to a pipe based on its interior roughness.
IDM
IDM refers to inch-diameter-mile. The program calculates this field by (Diameter x Length)/5280 feet.