A simple and easily adaptable analytical approach was developed for the hydraulic design of
micro-irrigation paired tapered laterals laid on uniformly sloping grounds based on the definition position
locations where the same average emitter pressure head existed in the uphill and downhill laterals．
Analytical expressions of the best manifold position，inlet working pressure head，coefficient of variation
by hydraulic variation and the limited length of the paired tapered laterals were separately developed by
using the energy gradient line method． Three tables showed the values used in estimating the design
parameters of the best manifold position，inlet working pressure head and coefficient of variation by
hydraulic variation，respectively，for the common diameter ratio，pressure loss ratio and velocity exponent．
When the length，diameter and designed emitter flow were given，the best manifold position and other
parameters of the paired tapered laterals could be directly designed without using iterative methods． When
the diameters，designed emitter flow and water application uniformity criterion were provided，the limited
length，the best manifold position and remaining parameters of the paired tapered laterals could be easily
determined by Excel Equation-Solver in Microsoft Excel． When the length，designed emitter flow and
water application uniformity criterion were provided，the design diameter，the best manifold position and
the remaining parameters of the paired tapered laterals could also be easily determined in Microsoft Excel
by the iterative technique． Three numerical design examples covering various conditions indicated that the
proposed approach could produce accurate results for practical purposes．
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