Observation Field Definitions

This tab allows you to record general observation information about the building or external source. You can record the results that the observation test produced, the source of the observation, and location information. This includes the distance, coordinates, and the direction from which the observation was made (i.e. upstream to downstream or downstream to upstream). In addition, if photographs were taken during the inspection, fields are provided allowing you to record the roll number and picture numbers. Some of the unique fields in this tab are described in the table below.

Field Name

Definition

Length

The Length field allows you to record the length (in feet) of area that drains to the identified source.

Width

The Width field allows you to record the width (in feet) of area that drains to the identified source.

Runoff Factor

The Runoff Factor is a value from 1-5 that relates to runoff coefficients in the Inspection Setup module and allows the inflow rate to be calculated.

Flow Rate (GPM)

The Flow Rate is measure in gallons per minute (GPM). GPM is calculated using the rational formula (Q=CIA).  The area is multiplied by the width.  The rainfall intensity is the one-year rainfall intensity value stored in the Inspection Setup module.  The runoff coefficient can be found in the table that correlates with the runoff factor in the Inspection Setup module.

Q = C x I x A

Q = Flow

C = Coefficient of runoff based on type and character of surface

Note: C can also be defined as the constant based on exterior factors (i.e. land type, land use, slope)

I = Rainfall Intensity

A = Area (in acres)

Flow Rate Lock

If the Flow Rate Lock is checked, the flow rate information stored in the previous field will be locked. This prevents the flow rate from being overwritten by a calculation.

% I/I Removed

The percent of infiltration and inflow that was removed due to the rehabilitation.

Remaining GPM

The Remaining GPM is a calculated field based on the percent of I/I removed and the total GPM.

See Also

External Source Observations Tab

Adding an Observation

Dye Test Tab