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2.2 CHAPTER TWO

• Identification of existing system components and service area
• Long-range projections of the area to be served by the water system
• Planning periods for the various water system facilities
• Present and future water demands
• Regulatory requirements for the ultimate approval and operation of the system
• Evaluation of alternative sources of supply
In addition, technical, environmental, institutional, financial, and operations and main-
tenance issues related to developing the recommended plan should be identified. This text
is concerned with the design of water treatment plant facilities and with those aspects of
master planning related to the physical features of design. Discussion of master planning,
therefore, is essentially limited to those treatment considerations outlined by the chapter
subjects. In addition to process and facility design issues, the scope would also include
• Site and facilities arrangement
• Environmental impact
• Construction costs
• Operations and maintenance (scope and costs)

Where design is to rehabilitate an existing plant, many of the data, such as operations
and maintenance costs, may be provided from past experience. In this case, background
site and environmental experiences may also exist to guide future direction.
More master planning difficulties are encountered in the design of a completely new
facility. In this situation, background process and cost data are usually obtained from
nearby operating facilities, from the experience of other water supplies with a similar wa-
ter source, or from references such as those published by the U.S. Environmental Pro-
tection Agency (USEPA) and the AWWA on typical treatment costs. Other factors such
as the influence of site location and environmental impacts would need to be developed
from local knowledge.
The most important considerations in preparing a master plan are to
• Provide general guidelines for future water treatment action.
• Develop possible alternatives for further evaluation unless background data from
existing experiences are so overwhelming that final decisions on treatment are
obvious.
• Enable a liberal use of contingencies in developing cost estimates, with the magnitude
of contingencies reflecting the confidence in the cost base. It is important that the owner
not be led into quick acceptance of a treatment program that eventually turns out to be
too costly. If the available information is questionable, it is best to delay program dis-
cussion until more meaningful background information is available.
• Include, as much as possible, potential features limiting site locations and environmental
impacts in the early determination to resolve which alternatives obviously should be
eliminated and what difficulties may be encountered with other options.

Principal Influences on the Master Plan

The principal influences and controls on developing water treatment process options in a
master plan include