Why a Watering System
Development of a good pasture watering system can make or break a
grazing system. Several considerations for the producer are:
- Water quality and quantity
- Supply equipment
- Groundwater protection
- Human and animal safety
Water Requirements
Water requirements for beef animals vary from about 9 gallons of
water per 1000 lbs. bodyweight per day in winter; to nearly 30 gallons
per 1000 lbs. bodyweight per day on hot summer days. For management
intensive grazing applications, the total water supply must be adequate
for the herd; but may have much more constant demand on the flow rate
than in non-intensive grazing applications where the entire herd goes to
water at once. If the water tank is placed within 500-800 feet of the
paddock, cattle will visit the tank one at a time or a few at a time,
creating less demand for access to the water tank.
Supply Equipment
Tank Sizing: Many producers are using water tanks that only
hold 20-50 gallons. Ample valve sizing and proper sized water pipe
combine to keep the tank water level near full as cattle are drinking
reducing the risk of cattle tipping the tank over. Only in the case
where a slow or intermittent pumping source is used, for example, a
direct-connect solar pumping system, will a large tank be required that
holds a day’s water supply or more.
Tank valves: Select tank valves based on the maximum flow rate
needed at the tank. Some inexpensive float valves can only supply 2-3
gallons per minute, which will often be insufficient for small tanks
where two or more cattle are drinking at a time. Slightly more
expensive, full–flow floats can deliver up to 20 gallons per minute with
the proper pipe and system design. A bottom-inlet float device on the
tank controls the water level but is generally out of reach of the
cattle.
Wellhead Protection: Protect wells and groundwater from pollution
by proper construction at the wellhead. Guidelines for wellhead
construction and upgrading are set by the Illinois Department of Public
Health. Abandoned wells need to be sealed according to accepted
practice.
There is a potential danger of groundwater contamination from livestock
watering equipment. Any tank or waterer supplied by well water or a
water district pipeline should be fitted with a vacuum-break or backflow
prevention device to prevent tank water entering the water supply in the
event of a line pressure loss. Most top-mounted commercial float valves
have an air gap or anti-siphoning valve, but plumbing codes and/or
health department regulations may require specific backflow prevention
equipment.
Energy-free or electrically-heated permanent waterers should be sized
for one watering space (1 cup or 2 lineal feet of tank) per 25 head.
Midwest Plan Service, MWPS-6, Beef Housing and Equipment Handbook, has
details on pasture tanks and freeze-proof waterers.
Refer to Midwest Plan Service MWPS-14, Private Water Systems Handbook,
for information on how to develop various types of springs for a water
supply.
Ponds and streams can provide water for cattle in pasture systems, but
it is desirable to fence cattle away from such surface water when
possible, allowing only a small access to the water. A good alternative
is to provide an appropriate pumping system to deliver the water from
the pond or stream to a pasture tank.
Siphons: When a pond or other static water source is not too
distant from the pasture being developed, it is sometimes preferable to
keep the cattle away from the pond by routing pond water to a tank
through a siphon. A siphon is a gravity-feed water delivery system that
encounters a rise in the pipe between the inlet and the outlet; for
example, you might want to deliver water from a pond over (instead of
through) the pond bank and down to a water tank at some elevation lower
than the pond water surface. The siphon outlet must be lower than the
level of the pond, and the water pipe must be guaranteed to be
leak-proof from the pond waterline up, to prevent losing the prime.
Friction losses in the pipe must be taken into account in order to get
adequate water delivery. A float valve on the tank is adequate for
controlling the system. Use a floating inlet or gravel screen inlet in
the pond, keeping in mind that any screen on the inlet will add to the
total pressure drop and reduce the flow rate to the tank.
Ram Pumps: In rare instances, there is a spring-fed stream with
adequate flow and gravity head to install a ram pump that will water
cattle uphill from the stream. No other power source is needed. Check
with the manufacturers for specifications; remember that a ram pump will
deliver only a fraction of the water that goes through the pump. One
manufacturer’s literature suggested a ram pump with 1-foot drop to
10-foot lift should deliver approximately 15 to 20 percent of the water
that it uses.
Solar Powered Pumps: Some pasture operations have a water source
available but no electric utility power nearby. In this case a
solar-powered pumping station may make sense. Solar systems are usually
set up with a large tank, with up to five day’s supply of water, so that
cattle will have water during cloudy periods when solar pumping is
reduced. Contact University of Illinois Extension or USDA Natural
Resources Conservation Service for help on sizing these systems; the
technology is well established and there are several sources of
equipment. The economics of solar pumping won’t be favorable for every
situation. It’s possible to use solar energy for virtually any
application; but the deeper the well or greater the lift, and the more
flow rate required, the more expensive the system.
Wind Powered Pumps: During the May-September grazing period, wind
energy in Illinois is much less reliable than solar energy. Economic and
operational studies show that solar is a better buy than wind for
pasture pumping. However, a hybrid wind/solar system may be economical
in some situations and may work well with an extended grazing season.
Contact the University of Illinois Department of Agricultural and
Biological Engineering for more information on wind energy.
Nose Pumps (cattle-operated): For lifting water up to about 20
feet and for fairly short distances, the nose pump will work well. The
animals pump water a stroke at a time via a piston/valve arrangement by
pushing the plunger back during drinking. Only one animal can access it
at a time, so it won’t be too practical for larger herds. Figure each
nose pump will serve about 25 head.
Shallow-well Pumps: The simplest type of pump for use on a well
is a shallow-well suction pump. A restriction on such a pump is the
maximum suction lift (depth to water plus friction head in the suction
line) allowable. A good foot valve is necessary, to avoid loss of prime
when the pump shuts off. Many shallow well pumps are not self-priming.
Theoretically, atmospheric pressure will let a pump lift water nearly 30
feet from the water surface; practically speaking the limit is more like
15 or 20 feet. To figure out whether a shallow-well or a deep-well pump
is needed where water is within a few feet of the surface, the well
draw-down under actual cattle-watering conditions must be known.
Electric Power Supply: Getting electric power to a pump requires
adequately-sized wiring to keep the supply voltage sufficiently high.
Low voltage at the pump motor, caused by poor wiring or too-small wire
size, can cause the motor to overheat and fail prematurely. Wire sizes
for pumps depend on two factors: full-load motor amps (FLA) and length
of wire run. Tables for figuring wiring sizes can be found in Midwest
Plan Service MWPS-28, Farm Buildings Wiring Handbook. Also consult the
Handbook for advice on grounding pumps and electrically-heated waterers.
Setting up the System
If you can gravity flow the water, linear low-density polyethylene (LLDPE)
pipe is sufficient. For pressurized systems, use a rolled high-density
polyethylene (HDPE) with a minimum of 150 PSI rated pressure. Use a
pressure-flow chart to select the minimum size needed.
The ideal system is to provide water to every paddock. Sometimes you
will have to use a lane to get cattle to water, using the same water
tank for several paddocks. Economic analyses of grazing systems indicate
that the money spent to provide water to several locations or to each
paddock pays back rapidly.
Distance to water should ideally be no more than about 800 feet from any
point in the paddock.
Keep water systems portable and flexible at first. It is probably best
to lay the pipe on top of the ground when you are starting management
intensive grazing, in case you want to make changes to paddock layout or
the water system. Bury pipe when you are certain the system is
configured the way you want it. You can install a main trunk line
underground and have risers with quick-disconnects for the tank or
tanks.
Other Considerations
Black pipe on top of the ground will heat water somewhat. Usually the
heated water is not a problem in summer, because cattle can best use
water at near rumen temperature anyway. Furthermore, if pipe is shaded
by vegetation the solar heating will be minimized. Keep the pipe under
the fence so the taller forage will provide shading.
Temporary or mobile tanks can be placed under an electric fence to keep
cattle pressure off the equipment and reduce tank upsets. Locating the
tanks in different spots each time the paddock is used can help reduce
the forage kill and mud problems around the tank. The area around all
permanent tanks should be graveled or otherwise treated to provide all
weather access. Consider using a combination of geotextile covered with
gravel to form a stable base around permanent water tanks. See Midwest
Plan Service AED-45, Using All-Weather Geotextile Lanes and Pads, for
more information.
References
For more information about water systems, contact your UI Extension
office or the local NRCS office. MWPS handbooks can be purchased from UI
Department of Agricultural Engineering or at
www.mwps.org.
Prepared by
Ted L Funk, Extension Specialist, Agricultural Engineering
Stanley Solomon, Extension Educator, Engineering Technology
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