Introduction and Definitions

Introduction
It is the goal of the Phoenix Water Services Department to deliver a cost-effective, adequate, and reliable supply of high quality water to Phoenix customers. To assure this supply, the Department has undertaken a number of planning steps described in three documents: The Water Resources Plan, the Water Conservation Plan, and the Drought Management Plan. This document revises the City of Phoenix Drought Management Plan of 1990. This new plan provides for appropriate responses to drought conditions, and response measures for other, non-drought shortages. Additionally, it provides for case-by-case exemptions from all or part of the water use restrictions for customers who have taken meaningful steps and made significant investment in water conservation prior to any drought or shortage occurrence. It also recognizes the distinction between using potable drinking water and treated wastewater during a declared water shortage.

Definitions
Though definitions vary, drought is generally interpreted as a set of complex physical and sociological influences over a large geographical area. It is not a distinct event, such as a hurricane, a fire, or a flood, but a combination of many coincidental factors working together over a period of time. In simple terms, a drought occurs when water supplies cannot meet established demands for a period of time that cannot be defined.

In its broadest sense, drought can be caused by seasonal or multi-year weather conditions, a curtailment of delivery from raw water suppliers because of water quantity or quality problems, a supply deficiency due to water supply system structural failure, or any of a number of natural or man-made situations.

A supply insufficiency occurs when the water available in an area is not sufficient to meet immediate unrestricted demand. While drought is usually systemic and regional in nature and of indeterminable length, a supply insufficiency may be system-wide or very localized, can be of relatively short duration, and may be caused by unforeseen increases in water demand or failure of a localized part of the storage or delivery system to provide a sufficient unrestricted supply of water.

Water demand reduction includes all measures taken by a water utility to reduce the use of drinking water in response to drought or supply insufficiency conditions. While a number of water conservation measures may be implemented or accelerated during drought, not all water conservation is a response to drought and not all demand reduction measures are factors in a comprehensive water conservation program. Conservation, by its very nature, should be a normal component of a well-run water utility which seeks to maintain a reliable water resource. It should be an on-going practical application of good citizenship in the community.

Conservation programs are usually voluntary and are driven by a desire of the City of Phoenix Water Services Department to extend the existing water supply, reduce the costs of finding and delivering additional water, and minimize the damage to the natural ecosystem caused by removing water or introducing wastewater. For customers, conservation efforts can decrease overall household operating expenses. For both the utility and customers, conservation activities are exercises in responsible behavior.

Water demand reduction during a drought may incorporate both voluntary measures and mandatory ones, such as curtailment of irrigation water use and, in extreme cases, rationing of available supplies.

Many of the organizational demand management responses to a drought condition -- including conservation measures -- are appropriate for responding to a short-duration supply insufficiency. Generally, responses to a systemic failure will be more rapid and may omit intermediate steps normally associated with an incremental drought response plan.

From areas which have experienced drought, it is evident that drought is not a constant or totally predictable condition in occurrence or duration. Rather, there are levels of drought and levels of drought impact.

Long-term indicators of available water include climate and weather conditions, soil moisture, water tables, water quality, stream flow, mountain snow pack, and watershed runoff. Indicators of such changes in the hydrologic cycle are termed first order impacts.

"And it never failed that during the dry years the people forgot about the rich years, and during the wet years they lost all memory of the dry years. It was always that way." - John Steinbeck, East of Eden

Second order impacts would affect food production, transportation, and industries that are particularly dependent on water resources, and sensitive to supply disruption.

A third order impact would be one that requires significant reductions in high water-use activities, requires serious adjustment in lifestyle, and impinges on the social welfare, behavior, economy, and health of the community. A supply insufficiency may have an immediate second or third order impact, but generally for a shorter period of time.