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RANNEY® SURFACE WATER INTAKES
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Ranney® Collector Wells Benefits
The Ranney® Collector Wells Surface Water Intake System offers
distinct environmental and economical advantages over conventional traveling screen intakes, trash rack systems,
and crib-style intakes. With low capital expenditures, lower operating costs and lower maintenance costs, the
Ranney® Collector Wells Intake is more economical than other types
of intakes. Specialized construction techniques eliminate disturbance of the natural bank, making
Ranney® Collector Wells Intakes preferred
environmentally, and easier to permit. The low entrance velocities of the water through the intake screens, the
adjustable size of the intake screen openings, and the offshore location of the screens offer significant
protection to aquatic life, while reducing maintenance associated with cleaning the screens.
Design
Each intake system is designed according to site-specific environmental and operation criteria. These criteria
are evaluated during preliminary design and include a review of riparian and instream environmental issues,
requirements associated with fish fry and egg entrainment, and stream flow and stage data. Field investigations
to develop bottom and velocity profiles and a geotechnical assessment of the subsurface conditions at the intake
assemblies and the caisson wet well are also conducted. This information is used to optimize screen sizing,
location, and entrance velocities (EPA Rule 316b), and to identify construction methods best suited for installation of the
intake lines. By optimizing screen design, the inlet velocities are often lower than downstream velocities,
which reduces the potential for fish entrainment and for clogging from suspended debris.
Construction
The Ranney® Collector Wells Surface Water Intake System consists of a large
diameter concrete caisson installed onshore with one or more intake lines extended to passive-type intake screen
assemblies installed in the surface water body. The caisson serves as a wet well pump station, with a pump house
constructed on top if necessary. Intake lines are projected or microtunnelled from the bottom of the caisson to
pre-selected locations in the surface water source, where the screen assemblies are attached and mounted on pile
supports. Because the intake lines are projected from within the caisson, no stream bank excavating or dewatering is
required. Instream work is limited to the pile installation and screen assembly attachment, with no cofferdams or
other excavation in the stream needed. The water enters the intake system through the submerged screen assemblies,
and is transported through the intake line and then pumped from the caisson to the point of service. Excluding the
pumping equipment, the system operates with no moving parts. The construction methods have been selected to minimize
impacts during construction, which often simplifies permitting.
Flexibility
Redundancy in surface water production can be obtained by installing more than one intake line, with each intake
line and screen assembly designed to independently carry the peak or average water demand. Additional pumps can
be installed in the caisson to allow operation while one of the pumps is out of service and to provide for emergency
and fire situations. The Ranney® Collector Wells Surface Water Intake
System can also be configured to include air burst back wash systems, manual or remote pumping controls, and
chlorination equipment, depending on the client's operational and water treatment needs.
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Ranney® Collector Wells,
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a Layne Christensen Technology
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6360 Huntley Road
Columbus, OH 43229
Toll Free: 1-877-4-Ranney (1-877-472-6639)
Office: 614.888.6263
Fax: 614.888.9208
E-mail: ranney@collectorwells.com
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