Head losses in storm drain junction boxes
"The paper outlines results of model studies of a junction box designed primarily for urban highway storm drains. Only full-flowing pipes are included. Loss coefficients are derived from consideration of total head loss across the junction box for straight through flow, for flow from a 90 [degree] lateral, and for combining flow from both directions, using various combinations of pipe sizes and flow rates. An example illustrates the use of the loss coefficient charts. The study also recognizes certain advantages in direct use of pressure losses. Close correlation is found between pressure loss and momentum change for straight-through flow, but the method has not yet been perfected for lateral and mixed flow."--Page 177.