Water is representative of Quadrant 2: the sterile, renewable resource. It is fundamentally fugitive, although it moves in predictable patterns. It is renewed by the planetary evaporation-precipitation process. One is concerned with its rate of occurrence Q, which occurs in a terrestrial network. Consumptive use evaporates water and returns it to the atmosphere; nonconsumptive use creates no vapor, but returns used water to the network for reuse. One thus distinguishes consumption and withdrawal. In important ways, these differ; both exhibit “networked rivalry” in different ways.

There are both steady and transient analyses that are important. Both use the same network, and both require capital investment. In the steady case, variability in either rainfall or upstream use is passed directly to downstream riparians. In the transient case, one adds intentional modification of this variability in order to manipulate or react to variability. Both cases require important resource management activities; both imply the deployment of significant capital resources in order to maintain and improve the natural distribution system. And all uses require a constant vigilance to ensure that nonconsumptive use, when returned, is not degraded in quality.

INTRODUCTION

How do we conceive the water resource? It is distributed, constantly renewed by a planetary geophysical distillery, invoking ocean, atmosphere, and sun. It is deposited as precipitation in catchments in which we live, defined by continental relief and orientation.