<p>A set of objects and routines to describe an irrigation system as a set of nodes, links, and farms; and solve water flow and withdrawal through the system. Water <em>flow</em> is solved by specifying water demand at nodes and withdrawing it, with residual water allocated proportionally to all other outflow links based on their specified design flow. Thus, this simple model does not rely on physical solution (i.e., the St. Venant equations) to calculate flow rate or depth.</p
