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NATURAL RESOURCES CONSERVATION SERVICE
CONSERVATION PRACTICE STANDARD
FISH RACEWAY OR TANK
(Ft. and Ft. )
DEFINITION through the tank center by means of a
standpipe or bottom drain.
A channel or tank with a continuous flow of
water constructed or used for high-density fish The raceway dimensions shall be designed
production. based upon the available water and planned
To provide a facility containing flowing
water of suitable temperature and quality Quantity – A water supply of sufficient volume
for dependable production of fish; must be available for the species being
produced either by gravity flow or by pumping.
To manipulate chemical, physical, and Generally, this amount would equate to two
biological factors to enhance fish complete water exchanges per hour for a
production; raceway length of 80 to 100 ft. The water
To maintain water quality. volume shall be measured during periods of
CONDITIONS WHERE PRACTICE APPLIES Quality – Water must be free of harmful
This standard applies to raceways or tanks that gases, minerals, silt, pesticides, and other
conduct flowing water to produce fish. It contaminants. A water analysis shall be made
applies to earthen channels as well as those before design and construction unless previous
channels and tanks constructed of concrete, use or experience indicates the quality is
concrete block, timber, rock, fiberglass, or satisfactory for the desired species. An
other materials. example of water quality requirements for trout
and catfish are shown in Table 1. Uniquely
CRITERIA different water quality parameters may be
applicable to other species.
General Criteria Applicable to All Purposes
The facility must be designed to provide
protection from flooding, sedimentation, and
contamination by pollutants from outside
Construction of fish raceways are generally
1. linear channels where water flows in at one
end and exits at the other end, or
2. circular, rectangular, or oval tanks where
water enters through nozzles or jets in a
manner that creates a rotary circulation
within the tank and discharge typically is
Conservation practice standards are reviewed periodically and updated if needed. To obtain NRCS, NHCP
the current version of this standard, contact your Natural Resources Conservation Service
State Office or visit the Field Office Technical Guide. September 2009
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practice, use the same or similar species to
those in the surrounding area to help minimize
Table 1. Water quality requirements any visual or aesthetic disruption.
Species Adequate provisions must be made to protect
Quality parameter Trout Catfish earth surfaces from wave erosion. Install
fences as necessary to exclude human,
Dissolved Desirable 8 ppm or > 5 ppm or >
animal, and vehicle traffic to allow for and
oxygen Minimum 5 ppm 3 ppm
maintain the establishment of vegetation and
Temperature Desirable 55 – 64 75 – 84 for safety considerations Road surfaces along
(ºF) Min./Max. 45 / 70 70 / 90 raceways and the outer perimeter of tanks
Desirable 6.5 – 9.0 6.5 – 9.0 shall be treated as needed to provide access
pH and reduce erosion. Dikes and levees should
Min./Max. 6.0 / 9.5 6.0 / 9.5
be crowned to provide drainage.
Carbon Desirable 2 ppm or < 5 ppm or <
dioxide Min.*/Max. 0 / 3 ppm 0 / 10 ppm
Criteria for Linear Channel Raceways
*Toxicity varies with dissolved oxygen concentration,
Channel raceways are generally of two types:
temperature and pH.
Concrete or concrete block construction.
Designed and construct raceways in
Predators. Fences, screens, nets, wires, or
accordance with current American Concrete
other materials shall be provided as needed to Institute (ACI). Codes for Structural Concrete
prevent the loss of fish to predators. Traps or or Concrete Masonry. Where concrete or
other devices that are potentially harmful for concrete block raceways are installed, the
humans, livestock, or pets shall be placed only bulkheads or check dams must be of the
in secure locations not normally accessible same specification.
except through special effort. A license or
permit from the appropriate state agency may Earthen channels constructed with a
be required to perform such activities. trapezoidal or parabolic cross section.
Construct raceways with a trapezoidal or
Waste treatment. Plans for treatment,
parabolic cross section. Bottom widths
storage, or use of waste generated or caused depend on the volume of water available but
by the operation of fish raceways or tanks shall shall be no less than 4 ft. Side slopes shall
be developed and made a part of the design be 1:1 or flatter depending on a saturated
and installation of the practice. Such soil slope stability analysis. Side slopes and
components may include the construction of bottoms of raceways must be smooth and
waste storage ponds (425), storage structures uniform to minimize dead water areas.
(313), treatment lagoons (359), settling basins,
or other facilities. Waste utilization (633) by Grade. Wherever possible, design and
the spreading of waste on land through construct raceways with a minimum bottom
irrigation or hauling is permissible if soils and grade of 0.5 ft. per 100 ft. The raceway outlet
land resources are available according to a will control the water surface grade.
Nutrient Management Plan. Discharges into Length. The maximum length of each
streams must meet state standards for the raceway section is determined by site
stream, based on size of the operation, and topography and need for re-aeration of the
comply with National Pollutant Discharge water but should not exceed 100 ft. Depending
Elimination System (NPDES) regulations. on water volume and quality, raceway sections
Protection. A protective cover of vegetation may be constructed in series by installing a
shall be established on all exposed surfaces bulkhead or check dam at the lower end of
that have been disturbed. If soil or climatic each section.
conditions preclude the use of vegetation, Width. The width of individual raceways shall
other methods may be used for protection be selected considering the available water
(Critical Area Planting – 342). When supply, harvesting equipment and operating
revegetating the earthen components of this and maintenance needs of the system.
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Freeboard. The minimum difference in bulkhead between sections and at the exit end
elevation between the water surface in the to prevent loss of fish. They shall be placed at
raceway and the top of the bulkhead, dike, or least 6 to 8 in. upstream from the flashboards
levee alongside the raceway is 0.5 ft. and shall extend at least 6 to 8 in. above the
expected water level to prevent fish from
Dikes and levees. The minimum top width of
escaping by jumping. Openings for screens
an earthen dike or levee shall be 6 ft. Side
shall be designed considering the size range of
slopes of earthen dikes and levees above the
fish to be separated. The water velocity
designed water surface shall be 2:1 or flatter.
through screens shall be slow enough to
When the top of the dike or levee is to be used
prevent impinging of fish against the screen.
for a road, the minimum top width shall be 14
ft. with at least 3:1 side slopes. Aeration. Each bulkhead shall be fitted with a
weir overfall. Flashboards in the opening or
Bulkheads. Structural or earthen barriers
throat section of the bulkhead may be used for
called bulkheads are to be placed across
this purpose. The width of the weir or weirs
raceway channels to create shorter sections, to
should be equal to the bottom width of the
establish and maintain the desired water levels,
raceway but shall not be less than 4 ft. where
and to provide aeration of the water. In
flashboards are used to establish the desired
addition to serving as a barrier, they shall have
water level. Two or more weirs separated by
an opening or throat section that allows
rigid center sections shall be installed when the
complete drainage to the bottom of the
width of the raceway exceeds 8 ft. To increase
raceway channel unless other drainage
aeration as part of the design, arrange a splash
facilities are provided. Bulkheads may be
board or series of boards to create successive
constructed of earth, concrete, concrete block,
splashes or place nozzles in the tank above the
rock masonry, steel or other durable metal,
water surface. The minimum distance from the
treated timber, or a combination of these.
weir crest to the water level below should be no
Earthen bulkheads are to have a minimum top
less than 1 ft.
width of 4 ft. and side slopes of 2:1 or flatter.
Structural bulkheads used in earthen raceways
Criteria for Tank Raceways
must extend at least 24 in. into the sides and
bottom of the channel. Concrete bulkheads Tank raceways are circular, rectangular, or
shall have a minimum top width of 6 in. and a oval and are constructed of concrete, metal,
minimum bottom width of 8 in. Openings and fiberglass, or other suitable material.
cores in concrete blocks shall be filled with Fiberglass and a variety of similar materials
either concrete or mortar mix. The opening or commonly referred to as "plastic" tanks are
throat section of bulkheads may be constructed generally suitable if construction and support
of concrete, concrete block, wood, or metal. It are sufficient to provide strength and durability.
shall have slots or grooves along the vertical Noncircular tanks must have an interior
face that allow flashboards and screens to be dividing wall to obtain proper circulation.
installed. Construct tank raceways shall be constructed
at locations accessible to water supplies,
Drains. A pipe drain with minimum diameter management personnel, and feed and harvest
of 6 in shall be provided at the bottom of the equipment.
bulkhead unless flashboards used to establish
the desired water level can be removed to Water supply. Water inlets to the tank may be
provide complete drainage. Where possible, through jets or nozzles or similar devices that
each unit in a series should be constructed so provide a tangential force to the water in the
that it can be drained independently of the tank. Submerged nozzles should not be near
other units. the bottom because of the problem of uplift of
waste particles. The nozzles shall be
Screens. Screens shall be provided at the positioned so that flow in the tank is
inlet of the system if necessary to exclude wild counterclockwise to take advantage of the
fish. Screens shall also be placed at each
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natural tendency for water in North America to Impacts of cultivated non-native fish on
rotate in this direction. endemic fish populations.
Waste removal. Incorporate provisions for Existence of cultural resources in the
waste removal shall be incorporated in the project area and any project impacts on
design. Bottom troughs, screens, or center- such areas.
positioned drain pipe shall be provided as part
Conservation and stabilization of any
of the tank construction.
existing archeological, historic, structural,
and traditional cultural properties.
Consider the effect on: PLANS AND SPECIFICATIONS
Water budget, especially on volumes and Plans and specifications are to be prepared for
rates of runoff, infiltration, evaporation, specific field sites and include construction
transpiration, deep percolation, and ground plans, drawings, job sheets, construction
water recharge. specifications, narrative statements in
conservation plans, or other similar
Downstream flows and aquifers that could
documents. These documents are to specify
affect other water uses.
the requirements for installing the practice,
Volume of downstream flow that might such as the kind, amount, or quality of
cause undesirable environmental, social, materials to be used, or the timing or sequence
or economic effects. of installation activities including site-specific
Visual quality of downstream water
OPERATION AND MAINTENANCE
Short-term and construction-related effects
Prepare an operation and maintenance plan
on the quality of the onsite and
shall be prepared that provides for inspection,
operation, and maintenance of vegetation,
Movement of dissolved organic and pipes, valves, raceways, tanks, dikes, levees,
inorganic chemicals downstream and bulkheads, filtration, and other parts of the
towards ground water recharge areas. system.
Wetlands, riparian areas and water-related