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4.3
INTAKE FACILITIES

TABLE 4.1 Intake Location Considerations
Criteria Remarks
Local surface drainage
Water quality
Wastewater discharge points
Lake and stream currents
Wind and wave impacts
Water depth and variation
Water depth Maximum available
Adequate submergence over inlet ports
Avoid ice problems
Silt, sand Locate to minimize impact
Navigation Outside shipping lanes, designed for accidental impact
Trash and debris Provisions for unrestricted flowby
W.S. elevation Maximum practical hydraulic gradient
Treatment facility Minimize conduit length to treatment plant
Cost Lowest cost consistent with long-term performance and O&M requirements

discharge conduits. Where impact from zebra mussels can be expected, redundancy takes
on increased emphasis because of the need to provide periodic inspection and mainte-
nance of intake components. For systems served by a single intake, failure of the intake
system means failure of the supply, an emergency condition that, if not promptly cor-
rected, can become a water supply disaster.

Intake Location

Selecting the appropriate location for an intake facility must include an evaluation of the
major factors presented in Table 4.1. A thorough study should be made of water quality
data to help determine the best location for siting the intake structure. Where insufficient
data are available, a water sampling and testing program may be warranted.

TYPES OF INTAKE SYSTEMS

A variety of intake systems have been employed and can be generally divided into two
categories: exposed intakes and submerged intakes (Table 4.2). Additionally, many vari-
ations of these principal intake types have been used successfully. Intake systems are clas-
sified as either river intakes or lake/reservoir intakes because the circumstances, location,
and types of structures used are generally quite different. Intake towers are commonly
used in lakes and reservoirs and are usually located in the deepest water that can be eco-
nomically reached. Intake towers may also be incorporated into a dam that creates a reser-
voir and used as part of a river intake system. Water is conveyed from the intake tower
via a gravity pipeline or tunnel to the shore well or pumping station. Intake towers offer
permanence, reliability, and flexibility in depth of draft, but their cost is substantial and
accessibility can be problematic.