Existing Problem: Old Drip System with No Pressure Control, Pressure Compensating or Consistent Schedule (Orchard Application)

The base system is an orchard drip irrigation system with buried emitters (most systems of this type in Georgia are on pecans). The system has little or no pressure control and non-pressure compensating emitters. There are currently 800 systems in Georgia similar to this description. Systems without adequate pressure control will typically have pressure variations which cause areas of high pressure to receive more water than areas of low pressure. In order to supply adequate water to the areas receiving the least amount, other areas tend to get over-irrigated. The recommended practice calls for no more than a plus or minus 10 percent variation from the average emitter pressure when non-pressure compensating emitters are used.

Water Conserving Practice: Improved scheduling for the season.

The proposed system change is to vary water applications throughout the season to reflect changes in crop water use. This could be as simple as using daily or weekly pan evaporation rates as reported by the weather service. Other options include using soil moisture sensors, installing a Class A Weather Bureau Evaporation Pan on the farm, or installing an automated weather station with automatic data collection.

¹Potential No. of Irrigation Systems Affected	500
Estimated Water Savings (%)	30 (20 to 40)
²Average Year Water Savings (million gal.)	1996
³Dry Year Water Savings (million gal.)	4887
Est. Cost of Full Implementation on Avg. System ($, 1998)	$1,500
Statewide Costs for Full Implementation ($, 1998)	$750,000
Cost / Unit of Water Saved in Average Year ($, 1998 / million gal.)	$376

Estimated water savings that could be achieved by incorporating these methods range from 20 to 40 percent. The total estimated water savings in an average year if fully implemented would be approximately 1996 million gallons. The average estimated cost to implement is $1,500 per 70 acre system. The cost per unit water saved is about $376 per million gallons.

Source: Evans, R.O., K.A. Harrison, J.E. Hook, C.V. Privette, W.I. Segars, W.B. Smith, D.L. Thomas, and A.W. Tyson. 1998. Irrigation conservation practices appropriate for the Southeastern United States. D.L. Thomas (ed.) Geologic Survey Project Report No. 32. Georgia Geologic Survey, Georgia Department Of Natural Resources, Environmental Protection Division, Atlanta, GA 30334. 43p.