A Word on Water

Key Points In An Irrigation Audit

  

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Irrigation audits are a key step in checking the effiecieny of an irrigation system.  Efficiency is achieved when most of the water from an irrigation system is actually used by the plants in the irrigated landscape.  Conducting an irrigation audit and the resulting irrigatin efficiency results in several benefits:

*lower water use and lower water costs
*improved landscape appearance
*fewer wet spots and dry spots
*less water runoff
*less water lost below the plants roots
*less fertilizer needed

Irrigation audits should be done to evaluate an irrigation system's performance immediately after installation.  Doing so will mean that any shortcomings found from the audit will more likely be addressed instead of waiting months to survey the installation. 

An irrigation audit consists of a series of field procedures for collecting and gathering irrigation system information.  Once this data is compiled, the performance of the irrigation systems can be determined by measuring such characteristics like distribution uniformity and precipitation rates.

Conducting an irrigation audit is a matter of turning on one irrigation valve, or station, at a time.  Before testing a station, the valve should be turned on so that each irrigation head can be flagged and to visually inspect the station. 

It is important to be on the lookout for broken or unobstructed sprinklers, low/high trajectory sprinklers and leaks in the station.  These obvious problems should be corrected before beginning the test.  As for the flags, make sure that none of them interfere with the water flow from the sprinklers.

The key tool needed for an irrigation audit is a catch can.  These are small water collection devices of a particular throat area and dispersed throughtout a station in a grid-like pattern.  It is crucial that the dimensions of each catch can are identical to one another.  When it comes to placing the catch cans, the goal is to have a catch can near each sprinkler head and another one located halfway to the adjoining head.

The top of each catch can should be level and as low as possible to approximate the surface of the plant material.  If the device is not level, it may not gather the correct amount of water.  This will adversely affect the test results.  It also important that the catch device be far enough away from the sprinkler head to avoid the main spray from hitting the side of the catch can.