7-Point Checklist for New Turf Irrigation Systems
After years of experience irrigating sports fields and open spaces we have created the essential checklist to ensure your open space is designed and specified perfectly.
Here are the seven items you must tick off:
- Uniformity – critical for a good surface, irrigation uniformity is #1. If you don’t have it, some parts of your field will be dry and dying, whilst other parts are badly overwatered. The brown-green field is never a good look. The scheduling co-efficient (SC) is the best way to check – normally through an irrigation designer-consultant. Anything above an SC of 1.2 is simply not good enough these days, and especially during Summer with tight watering windows, a non-uniform watering application can potentially cost you the whole field.
- Consistent Flow and Pressure – Once your consultant gives you a base design with good uniformity and SC, you need to secure your water supply to maintain flow and pressure. Upgrading water meters or installing booster pumps or indeed pumps and tanks can be an expensive pill to swallow, but they may be your only option to guarantee a good surface. The irrigation industry in Victoria has seen an increase in designers using variable speed drive (VSD) pumps direct on the main to ensure perfect pressure, regardless of what the street pressure might be doing.
- Tried and True Products – Stick with proven products. Don’t be the guinee pig on new technology products that are unproven – your parks and sports fields are too valuable. Let others bed in new products, stick to what works, including reputable brands such as Rain Bird, Hunter and Toro.
- Use Poly Pipe –a lot tougher than PVC pipe this will make your system much more robust. Designers tend to run longer and straighter laterals these days in just one pipe size, which makes keeping stock for repairs easier.
- Follow Valve Box Assembly Guidelines – whilst most people don’t think about repairs and replacements when installing a new system – these are inevitable at some point in time. A minimum of 100mm crushed rock base then 2 x rows i.e. 4 pieces of 100×100 treated pine timber bearers under the valve box make for the perfect installation. This will stop the box from dropping and potentially touching the pipe. And there should be room under the valve assembly, so it is not sitting in the gravel or mud.
- Ensure a Professional Survey is performed – To ensure your sports field or open space irrigation system is spaced accurately insist that it is done by a surveyor. A survey pick-up for the as built drawings is also very beneficial when fault finding down the track, as well as future works.
Last, but not least, if your project is a new sport field construction you should consider item 7.
- New Sports Field Construction – For a whole new sports fields, it’s best for the irrigation laterals to be trenched in and installed once the field has been trimmed to sub grade with enough cover so that drainage lines can be installed over the top. A 4-bolt tapping saddle with SS nuts should be installed pointing vertically, then a 32mmx 1” end connector, then a 32mm Poly tail coming up well clear of the finished surface level. As the sand profile is installed and trimmed to grade the poly can be cut down to correct height and a poly elbow, artic riser and rotor can be installed at the correct height. PVC pipe coming out of the ground, with very long pipe pieces on an articulated riser is not the way to go. Potential damage to the pipe, threaded joints below subgrade, and greater pressure losses are normally the result.
Over the years we’ve seen so many new parks and sports field surfaces die in the first 1-2 years due to poor irrigation design and specification.
Following this checklist, and carefully considering these essential items, is the best way to avoid this happening. After all, producing a great surface is a long-term investment, so doing things right at the start can save a council significant time, money and unnecessary anguish in the following years.