SWMM56

Subject:   What are the  Units  for the  five   St .  Venant   Flow   Terms  in  SWMM   5  and  InfoSWMM ? The new  flow  (Q) calculated at during each iteration of time step as (1)          Q for the new iteration = (Q at the Old Time Step – DQ2 + DQ3 + DQ4 ) /   ( 1.0 + DQ1 + DQ5) In which DQ2, DQ3 and DQ4 all have  units  of  flow  (note internally  SWMM   5  has  units  of CFS and the flows are converted to the user  units  in the output file, graphs and tables of  SWMM   5 ).   The equations and  units  for DQ2, DQ3 and DQ4 are: (2)          Units  of DQ2 = DT * GRAVITY * aWtd * ( H2 – H1) / Length = second * feet/second^2 * feet^2  * feet / feet = feet^3/second = CFS (3)          Units ...

Subject: What are the Units for the five St. Venant Flow Terms in SWMM 5 and InfoSWMM? This is how the flow is calculated in a link in InfoSWMM.  It uses the   ·          Upstream and downstream head, ·          The user input length, ·          The weighted cross sectional area and hydraulic radius as I explained in the previous email, ·          The Center velocity, ·          The Center Cross sectional area, and ·          The Upstream and Downstream Cross sectional area. The slope as listed in the output file is more for reference and is actually not used in the St. Venant Solution .   The way the program usually works is that the friction slope lags the water surface head slope with the difference made up by the change ...