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: System with Better Pressure Control
The proposed system change would be to improve pressure controls to recommended design specifications. This might require installation of pressure regulators at each submain, or on sloped sites it might require the installation of preset pressure regulators at each lateral.

¹Potential No. of Irrigation Systems Affected	800
Estimated Water Savings (%)	5 (0 to 10)
²Average Year Water Savings (million gal.)	532
³Dry Year Water Savings (million gal.)	912
Est. Cost of Full Implementation on Avg. System ($, 1998)	$1,000
Statewide Costs for Full Implementation ($, 1998)	$800,000
Cost / Unit of Water Saved in Average Year ($, 1998 / million gal.)	$1,503

Estimated water savings that could be achieved by improving pressure controls range from 0 to 10 percent. The total estimated water savings in an average year if fully implemented would be approximately 532 million gallons. The average estimated cost to implement is $1,000 per 70 acre system. The cost per unit water saved is estimated to be $1,503 per million gallons of water saved.

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.