Water Management on Pastures: Moving Water With Pump And Gravity Systems
Excerpt from Publication 19, Pasture Production, Order this publication Table of Contents
GravityThe ability of water to flow from higher to lower elevations makes a gravity system the one to utilize whenever possible. With no moving parts or energy inputs, these systems can provide dependable, low-maintenance service. To allow for flow resistance in the pipe, a minimum delivery pipe diameter 1 1/4 in. should be used where the grade is over l%. For grades between 0.5% and 1.0%, a 1 1/2 in. minimum size is recommended. Grades less than 0.2% are not recommended for gravity systems. Lay the delivery pipe on a uniform grade to prevent airlocks from forming. Water tank volume should reflect livestock numbers and water demand. If necessary, add gravel to ensure the tank area is stable to withstand herd traffic. A float at the water tank or an overflow outlet would control these conditions. Put a shade canopy over the tank to control seasonal algae growth. Figure 6-1. A gravity powered watering system is a simple and dependable way of getting water to livestock.
Solar PowerPhotovoltaic (PV) or solar panels can be used to power pumping systems for a wide range of output requirements. Solar systems can be very reliable and low in maintenance, but are expensive and require good design for practical service. Two system designs can be used depending upon the application. Both systems involve storing energy to compensate for variances in solar radiation intensity. Systems that use energy storage in the form of pumped water held in an elevated reservoir have the advantage of design simplicity. Solar panels supply power to the water pump through a maximum power point device to deliver water to the reservoir only during periods of bright sunlight. Water from the reservoir is gravity fed to the stock trough and controlled by a float valve. Battery systems also store energy for use during periods of low sunlight intensity. Through a sequencing device, solar panels charge the batteries that power the water pump. Pump operation is controlled by an electric float switch to allow flow on demand to the stock trough. Proper design of a solar system is critical to meet the specific needs of the user. Consider a suntracker if you are concerned about space for sufficient number of panels. A tracker follows the sun as the day progresses and maximizes panel exposure to the sun. Figure 6-2. Schematic of a solar powered pumping system.
Heissler PumpThis pump was designed by Paul Heissler of Frankford, Ontario. It is an inexpensive system and can be built from materials around the farm. It has a 12 volt submersible pump sitting in shallow water driven by a tractor battery. A 45 gallon drum acts as a reservoir with a float to control water level. A small trough is attached. Water flows into the trough by gravity as the livestock drink it down. The pump will deliver 22 gallons per minute. The battery is covered to protect it from the weather. This unit sits on top of the reservoir. The height and distance water is pumped limits the use of the Heissler pump. The more energy required for pumping water the more often the battery needs recharging. The battery charge has lasted 24 days, drawing water up 10 ft and providing water to 44 head of cattle. Hydraulic RamsHydraulic ram pumps have been used since the 1700s. New designs with the same principles are being used today. Falling water is required to operate a hydraulic ram pump. If installed correctly the pump moves water as high as 10 times the fall. The weight of falling water drives a lesser amount to an elevation above the source of supply. The pump operates on the basis of the falling water opening and closing 2 valves with air pressure forcing the water to its destination. The volume of water a ram pumps depends on the size of the pump, the fall between the source of supply and the ram, the height to which the water is to be raised and the quantity of water available. Output ranges from 700 to 3,000 gallons per day depending on these factors. A small stream is an excellent source to water livestock. Water needs to flow into the pump at 1 to 5 gallons per minute. A fall of 2 ft or more is sufficient to drive a ram capable of pumping water to a stock trough at considerable elevation and distance. As the pumping rate is constant but generally slow, a storage reservoir may be necessary to accommodate high demand periods. Figure 6-3. A typical ram pump installation. Ram pumps operate on the power of falling water.
Wind MillsIn the past, windmills have been a proven part of the farm enterprise and could find greater use for livestock water purposes today. Though now a fairly expensive technology, currently manufactured windmills are reliable and need little maintenance, equal to their antique counterparts. Old windmills can be successfully rebuilt and may offer a practical alternative to the expense of new equipment. Modern windmills will operate in a stream, pond or shallow well. The pump sits on the surface or in the water. An airline connects the pump to the windmill. Air pressure generated by the windmill activates the pump. Water is pumped when there is wind. The windmill can be located up to 300 ft from the water source and at the best location to catch the wind. It can lift water up to 20 ft and pump 5 gallons per minute. As wind is a variable energy source, use a storage reservoir to provide a supply for periods of low wind velocity. Locate the storage reservoir within 1,000 ft of the water source. Pasture (Nose) PumpsUsing a simple pumping mechanism to draw water to a bowl, the nose pump is a good alternative to instream watering. Installation is quick and easy - easy enough to use as portable system for rotation pastures. Animals push a plunger with their nose to move water with a diaphragm pump into a bowl. The pump is a rubber diaphragm and 2 check valves. One push of the plunger brings water in on the forward stroke and again as it is released. The intake line incorporates a foot valve and strainer for reliable operation. The water source may be a nearby stream, pond or well of suitable quality. A disadvantage of the nose pump is that stock must water individually, limiting practical use to about 25 animals per unit. Maximum lift from the water source is 25 ft. Where there is very little lift required nose pumps can draw water from 200 to 3,000 ft, depending on the pump size. Nose pumps are relatively low in cost and installation expense is minimal. Animals must be trained to use them. Young calves may have difficulty at the beginning. Figure 6-4. A nose pump operates on animal power.
SlingpumpA slingpump is powered by flowing water or wind. It floats on top of the water and is anchored in the water. A water powered pump is driven by water flowing past the pump. This rotates the propellers and will pump 24 hr/day. A water flow velocity of 2 ft/sec is necessary. A wind powered slingpump is often used where there is little water flow such as in a pond. It sits on 2 pontoons for floatation, but is anchored. Power is moved from the propellers to a belt that rotates the pump. A holding is used to store water for use in low wind periods. The minimum depth of water required is 16 in. It will pump from 800 to 3,300 Imperial gallons per day. Floating debris such as leaves and branches can hinder the operation of a slingpump. Silt or sand can also plug water hoses. Gasoline Engine Powered PumpsPortable gasoline-powered pumps are available that offer reliable service for water transfer where other systems are impractical. When used in combination with a large storage reservoir it may be possible to limit time spent operating the pump. The major drawback with this system is the need for operator supervision during pumping and attention to the water volume in storage to assure a constant supply.
Related Links... on forages and pastures, visit Forages
and Pastures (OMAFRA)
For more information: Toll Free: 1-877-424-1300 Local: (519) 826-4047 E-mail: ag.info.omafra@ontario.ca
|
||||||||
