WMS:Customized Lag Time Equation: Difference between revisions

From XMS Wiki
Jump to navigationJump to search
No edit summary
No edit summary
 
(One intermediate revision by the same user not shown)
Line 5: Line 5:
where:
where:


<math>T_{LAG}</math> = watershed lag time in hours.
:''T<sub>LAG</sub>'' = watershed lag time in hours.


<math>C_t</math> = coefficient accounting for differences in watershed slope and storage.
:''C<sub>t</sub>'' = coefficient accounting for differences in watershed slope and storage.


<math>L</math> = the maximum flow length of the watershed along the main channel from the point of reference to the upstream boundary of the watershed, in miles.
:''L'' = the maximum flow length of the watershed along the main channel from the point of reference to the upstream boundary of the watershed, in miles.


<math>L_{ca}</math> = the distance along the main channel from the point of reference to a point opposite the centroid, in miles.
:''L<sub>ca</sub>'' = the distance along the main channel from the point of reference to a point opposite the centroid, in miles.


<math>S</math> = slope of the maximum flow distance path in ft/mile.
:''S'' = slope of the maximum flow distance path in ft/mile.


<math>m</math> = lag exponent
:''m'' = lag exponent


 
Therefore, if the equation the state, county, etc. uses to compute lag time is not available, it can often be set up using this equation by entering a custom coefficient, ''C<sub>t</sub>'', and exponent, ''m''.
Therefore, if the equation that your state, county, etc. uses to compute lag time is not available, it can often be set up using this equation by entering your own coefficient, <math>C_t</math>, and exponent, <math>m</math>.




Latest revision as of 15:11, 29 September 2017

Almost all of the lag time equations are of the form:

where:

TLAG = watershed lag time in hours.
Ct = coefficient accounting for differences in watershed slope and storage.
L = the maximum flow length of the watershed along the main channel from the point of reference to the upstream boundary of the watershed, in miles.
Lca = the distance along the main channel from the point of reference to a point opposite the centroid, in miles.
S = slope of the maximum flow distance path in ft/mile.
m = lag exponent

Therefore, if the equation the state, county, etc. uses to compute lag time is not available, it can often be set up using this equation by entering a custom coefficient, Ct, and exponent, m.


Related Topics


v • e
WMS – Watershed Modeling System
Modules:Terrain Data  •   Drainage  •   Map  •   Hydrologic Modeling  •   River  •   GIS  •   2D Grid  •   2D ScatterWMS.PNG
Models:CE-QUAL-W2  •   GSSHA  •   HEC-1  •   HEC-HMS  •   HEC-RAS  •   HSPF  •   MODRAT  •   NSS  •   OC Hydrograph  •   OC Rational  •   Rational  •   River Tools  •   Storm Drain  •   SMPDBK  •   SWMM  •   TR-20  •   TR-55
Toolbars:Modules  •   Macros  •   Units   •   Digitize  •   Static Tools  •   Dynamic Tools  •   Drawing  •   Get Data Tools
Aquaveo
Retrieved from "https://www.xmswiki.com/index.php?title=WMS:Customized_Lag_Time_Equation&oldid=130041"