on June 10 2013
Every time your sprinkler heads pop up and begin to water your lawn to ensure that it stays green and lush, a pump is responsible for supplying them with the water they need. A crucial but sometimes overlooked component of any irrigation system, pumps are available in different designs, allowing you to find the right one for your particular lawn configuration.
There are a number of technical features such as capacity, power and efficiency that will play a large role in determining your selection. Consider the following questions as you design your irrigation system to ensure that your pump is primed and ready to go whenever it's called upon:
• How powerful of a motor will you need?
• How can you ensure maximum efficiency?
• What types of pumps are available?
• What performance considerations are most important?
• What features would you like to have available?
Type, Performance and Installation
In addition to providing water for lawn sprinkling applications, pumps can boost water pressure for washing cars, boats, farm equipment and more. Heavy-duty units can be used to irrigate gardens, remove water, protect against fires and for a host of other applications. They may draw on water from a lake, creek, well or municipal water supply. Pumps may be fueled by electricity, gasoline or even propane. Consider how extensive your watering needs are, where you plan to draw water from and how much power you will need when selecting the ideal pump for your irrigation system. Surface Centrifugal Pumps:
Centrifugal pumps installed above the water level are the most commonly used type. They must be filled with water, or primed, prior to operation and can draw water from reservoirs, lakes, streams and wells. Centrifugal units use a rapidly spinning impeller to push water through the pump. Priming is required because they cannot suck air on their own, they can only provide suction for water.
Centrifugal pumps offer a wide range of capacities while providing a fairly constant flow rate. They offer an economical choice, though their efficiency and capacity may be somewhat limited compared to other pump types.
• May be installed either horizontally or vertically
• Horizontal installations may allow for easier inspection and maintenance
• Make sure joints and connections are airtight to ensure optimum operation
• May be powered by electricity or diesel fuel Submersible Pumps:
Unlike surface pumps, submersible pumps are installed completely underwater, motor and all. They function in a manner similar to a multistage centrifugal pump. The pump is often cylindrical, making it ideal for placement inside a well. Because they are already underwater, submersible pumps tend to operate with greater efficiency than other pumps. They may feature dry motors, which are constructed to prevent water from getting in, or wet motors, which function even when water is running through them.
• Submersible pumps do not need to be primed and are generally low maintenance
• Sleeves force water up over the surface of the pump to prevent overheating
• If using an electric model, be sure the cord is well-protected
• Submersible pumps operate more quietly than centrifugal pumps Turbine/Jet Pumps
: Turbine pumps are a sort of amalgamation of surface and submersible pumps, featuring a submerged pump and surface motor. They may be used in situations where the surface of the water supply fluctuates, because they can use suction to bring water up, providing installation versatility. With the ability to provide high-capacity performance at low-pressure levels, turbine pumps are useful for an array of functions. Turbine pumps often require a larger up-front investment and may be somewhat difficult and expensive to maintain.
• Turbine/jet pumps do not need to be primed
• Ideal for larger, heavy-duty applications, such as irrigating gardens or golf courses
• Operate quietly and take up little space
• Jet pumps must recycle water, diminishing efficiency Propeller Pumps:
Propeller pumps may be axial or mixed flow and are used in installations where the pump is located fairly close to the surface of the water supply and needs to generate a high flow rate. They do not produce high pressure, but they do provide high flow capacity. Propeller pumps are generally utilized in situations where suction lift is not necessary.
• Portable design opens up use for a range of applications
• Feature simple construction
• Available in a wide range of materials
Performance and Installation Considerations:
Points to consider
||• Simple construction
• Don't need to be primed
|• Cannot generate suction to lift water
• Provide low energy output
||• Enclosed impellers maximize efficiency
• Don't need to be primed
• Easy to install
|• May be less economical
• Ideal for booster applications
• Can only be powered by electricity
• Susceptible to lightning strikes
• Easy to install
• Constant flow rate
• Offer a wide range of different
|• Need to be primed
• Must be located fairly close to the surface
of water supply
• Losing prime may result in pump damage
||• Operate quietly
• Don't need to be primed
• May be used in wells
• May be used in conditions where water
|• Less economical
• May be more difficult to install, inspect and
• Require periodic impeller adjustments to
There are a number of important factors to consider when choosing an irrigation pump, including capacity. Capacity is measured in gallons per minute (gpm) and is a function of the motor's horsepower (hp), discharge pressure (measured in pounds per square inch, or psi) and the distance above the water pump is located. You'll want to find the proper balance between flow rate and pressure. Keep in mind that as the flow rate increases, pressure decreases and vice versa. Try to avoid long runs of pipe, as they tend to reduce efficiency.
Larger pumps and impellers with smooth finishes tend to operate with greater efficiency. If you live in a climate that experiences freezing temperatures in the winter, you'll need to winterize your irrigation system by disconnecting the suction and discharge lines connected to the pump, emptying water from all of the pipes and storing the pump indoors during the cold season.
• Residential pumps may be either 115 V or 230 V
• Motors usually range in power from 1/2 hp to 2 hp
• Larger motors tend to provide more volume and greater pressure
• Efficiency is lost as water travels through pipe because of friction
• Friction tends to be greater in steel pipes than plastic pipes
• Impellers may be closed, open or some combination of the two states
• Water pressure in municipal water supplies fluctuates throughout the day, so try to irrigate at off-peak
hours to utilize higher water pressure
Organic fertilizers are made from natural ingredients, such as manure, bone meal or blood meal and are broken down by soil microorganisms for the gradual release of nitrogen and other elements. Water Soluble:
Water-soluble fertilizers are powders or granules that are mixed with water, are easy to apply and make nutrients immediately available to plants. Plants derive nutrients from this type of fertilizer through their foliage and root systems. Liquid:
Available as either a soluble powder or a liquid, these fertilizers are first dissolved or mixed in water and are then sprinkled or sprayed onto plant leaves or applied using a watering can. Liquid fertilizer is quickly and easily absorbed into a plant's root system for an immediate boost. Because they leach into soil, liquid plant food needs frequent application, compared to other types. Liquid fertilizers can be used to help prevent transplant shock. Liquid fertilizers are also the easiest variety to incorporate into an irrigation system. Slow Release:
Slow-release fertilizers are sold as dry granules or pellets and work by releasing small quantities of nutrients each time a plant is watered. This type can be shaken onto the soil or pressed into the soil in pellet form. Slow-release fertilizers can last in soil from a few months to several years, which is one reason why these types are usually more expensive and are much easier to maintain. Slow-release formulas become activated by water so they work best underground where it stays damp. Fertilizer Spikes:
Fertilizer spikes are hardened, slow- or controlled-release dry fertilizers in the shape of a stake or spike, which is inserted into the soil of container plants, shrubs or trees.