Lawn Sprinkler Efficiency Upgrades Part II

sprinkler-head3Nearly 60% of residential water consumption can be attributed to landscape watering.

Hopefully you have read my previous posts on “Lawn Sprinkler Efficiency and Chasing Lawn Sprinkler Leaks “. If so, you recognize that a fine tuned system can provide greater efficiency and reduced water usage. However, you may want to go further. Stage III and IV represent some significant decisions regarding  the way you treat your landscape.

Stage III:  Plan to get wet and dirty. This stage will impact the designed water delivery. These changes are a  bit lengthy and involved and may take several weekends to complete the items.

  1. Make a sketch:If you don’t have a drawing of your system, use sprinkler flags to identify each sprinkler head in the zone. You want to identify all heads associated to a zone, one zone at a time. Each existing nozzle/head should include a brand and  a number on the top edge, 10, 12, 15. As well as a pattern identifier 1/4, 1/2 or F.  Sketch out your lawn and zone. Typically, residential irrigation systems are designed based on 30 PSI of water pressure at the head. Go to the manufacturers webpage and look up the GPM usage for each head.   On your sketch identify each head by pattern, radii and GPM. Total the GPM per zone. TIP: Whatever changes are made in the following steps, do not exceed the calculated GPM by more than 10%.  
  2. Correcting design issues: After completing item 1 and 2 you may have noticed some sprinkler heads are not exactly in the right place. This may be based on poor placement, changes or growth in the landscape material.  If relocation is required ensure that you retain adequate head to head coverage with the neighboring sprinkler heads. TIP: Read the nozzle; if the nozzle is stamped with a 10′ on the top, you should have other heads within 100 to110% of the distance of that number  from the head location. So if you decide to move the head, locate the neighboring heads to ensure the relation lawn20edge20pop20up2011stays comparable.
  3. sprinkler-bodies1Replace Sprinkler Body: Similar to #2, but the solution may be to obtain a sprinkler body that allows the nozzle to extend above an obstruction.  If you find pop-ups in flower beds but the spray is obstructed by plant material, changing the head to a riser can provide the necessary reach allowing sufficient coverage. TRICK: Risers (ridged plastic pipe with nozzles) can use the same nozzles as pop-ups but require a transition fitting to convert the threaded pipe to a sprinkler head nozzle. These fittings are brand specific as well.  
  4. Convert from Spray to Stream Nozzles: This is a dramatic change, not to be taken lightly and I would only convert one section at a time to see if you are okay with the results and performance. Even though everything you have done to this point will be beneficial, changing the nozzles will drastically reduce your water usage, but may require longer watering durations. Look for a future write up on Nozzles for a comparison in the water usage. As an alternative to this you may try finding nozzles that are low arc, as lowering the trajectory arc  you are spraying less water high up in the air. Since the  low arc nozzles typically have shorter radius patterns, this may not work, but is worth keeping in mind as you can use nozzles with different arc’s in the same system. Read my article on changing sprinkler nozzles; the payback is not as much as you might want but its worth a look.
  5. Parkway’s: In my neighborhood, I see a tremendous amount of water traveling down the street (everyday) due to this type of runoff. If the area is watered with standard half and quarter circle nozzles, you may consider changing the nozzles to strip spray nozzles. Strip spray nozzles project a rectangular pattern and may help you manage the water usage and overspray. Technically this is still a spray nozzle and it is okay to mix this head with other spray nozzles.  As I mentioned earlier, Irrigators will collect sprinkler heads together to complete a zone water budget, so this zone may include heads in the main body of the lawn and this could complicate your efficiency measures.

Stage IV: More dirt more wet. This stage is very severe, so only consider these steps if you believe you are still not where you want to be with regard to water usage.  Some of these steps are major redesign initiatives and its a lot of work. Hiring someone to do the irrigation work can be expensive as installing new sprinkler systems. You will need to be the judge on Stage IV. I don’t consider these items in order, so weigh your options. 

  1. Change Landscape Material: By changing your plant material to drought tolerant regionally specific plants, you can successfully reduce your watering requirements for your flower beds. Granted if you still have a large amount of turf your water demand is still high. You may consider reducing the percentage of turf. You can replace it with plant material or porous aggregate (gravel, crushed granite, river rock, etc.)
  2. Stop Using The In-ground Lawn Sprinkler: Simple to accomplish and it will dramatically reduce your water usage. Granted, you are back to dragging hoses around the house but point-of-use sprinklers will not use near the water an in-ground system uses.
  3. sprinkler-controllerReplace the Lawn Sprinkler Controller:  Understanding that better water management can further reduce our water usage, typical Sprinkler Controllers (or Timers) provide water on a timed bases. If  the timer is equipped with rain, wind or freeze sensors they will provide a higher degree of water management. Hopefully you already have those add-on devices to your existing controller at this point. However, in Stage IV stepping to a digital grade of water management is required to reduce your water consumption further.  At this point, I have found limited products available directly to the public as most of the “Smart Controller” are defined to be professionally installed.  Many of them require a monthly fee as they are tied to a weather database for regular downloads (I dont like monthly fees). However, I recently found a product called Cyber-Rain. They appear to be headed down the right track, by using your PC and the Internet to upload the most current weather conditions to adjust the water settings accordingly. They use a wireless connection to get to your PC and provide you proprietary software to further manage the water delivery. At $400 it’s a bit steep if you compare it directly to a entry level $60 water timer, however here in Stage IV, we are very serious about water conservation. I have not tested this product but so far I like what I see.
  4. Water Only The Flower Beds.  In my part of the country watering flower beds serves two purposes, 1) to keep the plant material alive and, 2) it reduces opportunities for foundation problems associated with the expansion and contraction of the soil. Assuming your system design has the flower beds in their own zones, it will be simple to just turn off the other zones at the controller.  If you have Bermuda grasses, you can stop watering them  and the grass will go dormant, but don’t try this with St. Augustine or Fescue as this grass will die without water. If the flower beds are combined with the turf sprinklers you may consider #5.
  5. Rezoning  sections: By now you should know where each section is, what it waters and how much water (GPM) per section. Segregate flower beds into their own zones. This may include digging and re-piping some heads from the flower bed zone to another zone.
  6. Convert Flower Beds To  Drip Irrigation: This is all based on the flowerbeds being zoned separately. Since drip system run at lower pressure, you will need to change the zone valve that can support the lower pressure.  Then its a matter of capping the existing sprinkler heads (or turning them off). I have used the (brown tubing) drip-line style, its not quite as efficient as the point-of-use designed to water individual plants as it just has an emitter every 12″ but its a lot less drip-linework and maintenance. If you use this style, the home supply stores can provide you the material required to transition from a sprinkler riser to the new drip lines.
  7. Convert Parkways And Grass Strips to Drip Irrigation: Assuming you can isolate the parkways into their own zones you can use the same drip line mentioned in #4 by burying it about 3-4 inches below the ground spaced at 12″. I did this at my house and have been very pleased with the results. TIP: If you do this, be very careful if do any digging  in the future as this type line is very pliable and can easily be damaged with a shovel.
  8. Add Rainwater Collection: This can be  a major undertaking, I have wanted to do this myself and have researched it for several years but due to certain limitations  on my property its not feasible…yet.  By creating a full house rainwater collection system you could technically rework your system to rain-water-collectionuse nothing but rainwater to irrigate your property.  But here are some things you would need to consider if you are interested. 1)Storing the water, probably in the neighborhood of 1000 to 3000 gallons. 2) Pumps may be required to transfer the water and drive the water through your sprinkler system. 3) Zone valves may need to be changed to accept the water as it will have a bit of dirt in it, 4) Additional filtration may be required to keep the system from prematurely stopping up the standard sprinkler heads. On the other hand, as a simplier approach, using water barrels at the gutters you can easily use this water for hand watering applications.
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2 Responses to Lawn Sprinkler Efficiency Upgrades Part II

  1. […] may also find benefit in reading the other articles I have written on the subject: Lawn Sprinkler Efficiency Part II, Lawn Sprinkler Efficiency Part I ,  Searching for Lawn Sprinkler Valves, Chasing Lawn Sprinkler […]

  2. […] Lawn Sprinkler Efficiency Upgrades Part II « Homeownerbob’s Blog says: April 26, 2009 at 4:23 pm […]

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