Date of Award:

5-2009

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Civil and Environmental Engineering

Advisor/Chair:

Michael C Johnson

Abstract

The use of residential secondary or dual water systems for irrigation purposes is common in the western United States where water supplies are scarce. While the use of non-potable water in secondary systems has successfully curtailed demands on potable systems, experience has shown that overall water use actually increases with the introduction of a secondary supply because users commonly pay a fixed fee and have unlimited water use. While water metering and billing effectively reduce water use, there are two main obstacles to the widespread installation of meters in secondary systems.

The first obstacle is that standard residential water meters do not normally function in debris-filled secondary water. Metering mechanisms can clog or be degraded by suspended debris of both organic and inorganic nature in the water. By way of innovative meter designs or filtration, a few secondary systems have had success metering their secondary water. Other systems have experimented with possible debris-resistant meters but have had little success.

In addition to the physical limitations of water meters, secondary systems face economic obstacles from the increased expense of metering. Since secondary water is intended to be an inexpensive alternative to potable water for outdoor irrigation, any cost increase due to the expense of meters, filtration, meter reading, etc., interferes with the main objective of a secondary system. A system-specific economic analysis is necessary to determine the financial feasibility of the implementation of metering in any secondary system.

The objective of this research is to identify feasible ways for metering secondary water systems. An overall analysis is made of the performance, benefits, and drawbacks of each technological approach. Approximate costs and design requirements of these technologies are identified, thereby allowing water suppliers to determine the economic feasibility of metering. In addition, other design precautions for implementing secondary metering and investigations of residential meter performance in secondary systems using filtration are discussed.