Att-Kin Routing Equivalency in HydroCAD?

[danmurphyIV]

I am reviving an old thread. Is there any way to do the following now with the new routing procedures in HydroCAD (i.e. Muskingum-Cunge)?

I am updating a TR-20 watershed for a large watershed in HydroCAD. There are several reaches defined in the TR-20 model. TR-20 uses the Att-Kin reach routing procedure and describes these reaches with a length (L), end area coefficient (x), and an exponent (m). All of the reaches use an exponent of m = 1. No other information, including any elevation or slope information, is given regarding the reaches. Does anyone have any experience with this? In what manner can I model the reaches in HydroCAD? I need to model these reaches without gathering or estimating any more parameters than are included in the TR-20 model. Thanks.

 

[psmart]

The NRCS has discontinued the use of Modified Att-Kin (MAK) in the Win/TR-20 Software, in favor of the new Muskingum-Cunge procedure.

For enchanced compatibility with Win/TR-20, the latest HydroCAD-8 release also provides Muskingum-Cunge reach routing. For details see

http://www.hydrocad.net/mc.htm

HydroCAD does not currently support the older MAK procedure. Although MAK may be considered for a future update, it's use of the derived X and M parameters doesn't provide the complete reach cross-section needed for other HydroCAD calculations.