Irrigation Auditing & Management

The greatest change in the landscape industry in the last five years has been in the area of water management. Several variables come into play when discussing water use, and planning for future water costs and water budgeting. Of course, last year’s water use is not necessarily reflective of what this year’s water use will be since our weather is never exactly the same year to year. Two factors that greatly influence water irrigation requirements are:

• Water evaporation – the amount of water that has been lost to the atmosphere due to the current weather, wind, heat, amount of sunlight, etc.
• Water transpiration – the amount of water the landscape vegetation has used up in its growing process.

The amount of daily water loss as a result of water evaporation and transpiration is referred to as evapotranspiration, or ETo. ETo is measured in fractions of inches per day (e.g., an ETo of 0.25 represents a one quarter inch loss of water on a specific day). ETo loss is approximately 1.2 to 1.35 inches per week during the summer, 0.25 to 1.2 inches per week during the spring and fall, and 0.25 to 0.5 inches per week during the winter.

As your landscape contractor, our goal each week is to manage your irrigation cycles to replace the water used last week, based upon last week’s ETo and certain other factors, such as:

• Precipitation Rate, or the amount of water a specific valve applies through the sprinkler heads.
• Distribution Uniformity, or a measure of how efficiently water gets applied via the sprinkler heads.
• Climatic Conditions, or the degree of exposure to sun, wind, salt air, etc. a particular landscape is subjected to.
• Site Conditions, or the amount of pavement, buildings, etc., bordering the landscape.
• Crop Coefficient, or the specific water use requirements of the plants making up the landscape.

Holmes Landscape Company collects this detailed information for each landscape we manage, right down to the actual precipitation rates for every rotor and impact system valve under our control. Our computerized water management program accepts last week’s ETo and recommends this week’s irrigation runtimes based on each valve’s profile. There is absolutely no better way for us to irrigate!

Irrigation monitoring is but another tool that makes Holmes Landscape Company successful in providing its customers with the highest quality landscape maintenance program possible.