{"id":426,"date":"2017-10-23T21:33:50","date_gmt":"2017-10-23T21:33:50","guid":{"rendered":"https:\/\/learn.hydrologystudio.com\/stormwater-studio\/?post_type=ht_kb&p=426"},"modified":"2024-08-08T18:27:22","modified_gmt":"2024-08-08T18:27:22","slug":"runoff","status":"publish","type":"ht_kb","link":"https:\/\/learn.hydrologystudio.com\/stormwater-studio\/knowledge-base\/runoff\/","title":{"rendered":"Storm Sewer Runoff"},"content":{"rendered":"\n

Stormwater Studio uses this data to compute flows in your system. You can enter known Qs directly and\/or specify Rational method data. If a particular Line does not have any incoming overland flows, i.e., a manhole, then the runoff data can be skipped. The program will carry upstream flows through the Line to the next downstream Line.<\/p>\n\n\n\n

Runoff Data<\/h2>\n\n\n\n
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Area Id (optional<\/em>)<\/strong>
Enter any user-defined text that describes this drainage area. This value will appear in related reports.<\/p>\n\n\n\n

Known Q<\/strong>
Enter any known or additional<\/em> flow for this Line. This is in addition to any flows the software computes by the Rational method. This value can be positive or negative, is added to any other incoming flows and is carried downstream to be added to other downstream Lines when “Accumulate Known Qs” is checked in the Ribbon menu Pipe Design tab. When unchecked, the Known Q is unique to this Line only and is not carried downstream.<\/p>\n\n\n\n

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Note that when “Use inlet captured flows in System” has been checked on, any Known Q’s will be ignored on manholes or non-inlet type junctions.<\/p>\n\n\n\n

Drainage Area<\/strong>
Enter the drainage area that contributes to this Line only. <\/p>\n\n\n\n

You can optionally draw custom drainage areas on your Plan by first selecting any Line and then drawing its associated drainage area. You add up to 50 points with simple mouse clicks to describe the boundary or polygon. The software automatically computes the drainage area and inserts it into the Drainage Area input field. The areas are displayed on your Plan at various colors and opacity that reflect the Runoff Coefficient. Complete details here<\/a>.<\/p>\n\n\n\n

The program will accumulate the drainage areas of all of the Lines during the calculations.<\/p>\n\n\n\n

Runoff Coefficient (C)<\/strong>
Enter the runoff coefficient corresponding to this drainage area. See Runoff Coefficients <\/a>for suggested values.<\/p>\n\n\n\n

Composite Coefficients<\/em> – Stormwater Studio will compute a weighted or composite coefficient by clicking the ellipsis […] button next to the data cell.<\/p>\n\n\n\n

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Enter up to 3 unique descriptions, areas and runoff coefficients. Check the option to include in printed reports if desired. The computed composite value will be entered as the Runoff Coefficient.<\/p>\n\n\n\n

Tc Method<\/strong>
Stormwater Studio provides the option of using a known Time of concentration (Inlet Time) or calculating it using the TR55 method.<\/p>\n\n\n\n

Inlet time is the time it takes for runoff to travel from the remotest upstream point in the drainage area to the inlet in question.<\/p>\n\n\n\n

\"\"Choose the Tc Method by selecting from the drop-down list box.<\/p>\n\n\n\n