and L3 < L2 < L1. Given a parameter set and unit inlet flow rate
(qo), the following procedure can be used to determine the
parameters of equation 10: (1) determine L1 as the length of
a block that is irrigated as a unit (discussion on how to
determine L1 is presented in the design section of this article);
(2) select the minimum acceptable length (L3) based on
operational and economic considerations; (3) determine rL
using equation 12; (4) determine L2; (5) determine tco(L1),
tco(L2), and tco(L3) using a simulation model, such that Zmin =
Zr in each case; and (6) calculate 1, 2, and 3 using
equation 11