Existing Problem: Pressure Gages are Not Operating

Pressure Gages Each irrigation system has an optimal operating pressure range for its sprinkler or spray nozzles. For those with pressure compensation in the nozzle or riser this is a wider pressure range; in most systems lacking pressure compensation, the optimal range is quite narrow. Differences in the amount of water delivered and in the spray pattern are common when pressure is above or below the optimal. Gages with needles that do not return to zero when the system is off, or that don't move above a minimum when the pressure increases are the first candidates for replacement. All gages should be checked during routine calibration.

Water Conserving Practice: Replace/Repair Pressure Gages

New Pressure Gage A system operating at the correct pressure, as indicated by a functioning gage, will operate more efficiently. Diesel, propane and gasoline engines that drive pumps must be periodically reset to run at correct RPM to maintain proper operating pressure. Worn pumps, incorrect voltage on pump motors and leaks can affect pressure. These and other modifications to the system may be required to ensure proper pressure is maintained throughout the system.

¹Potential No. of Irrigation Systems Affected	6,500
Estimated Water Savings (%)	0 (-5 to +5)
²Average Year Water Savings (million gal.)	0
³Dry Year Water Savings (million gal.)	0
Est. Cost of Full Implementation on Avg. System ($, 1998)	$50
Statewide Costs for Full Implementation ($, 1998)	$330,000
Cost / Unit of Water Saved in Average Year ($, 1998 / million gal.)	0

Estimated water savings are between -5 and +5 percent if improvements are made. The largest improvements are based on systems which have been over-pressurized. The average estimated water savings is 0%. The effects of over- or under-pressurized systems are poor uniformity, incorrect application rates, and possibly wasted water. The latter is particularly true when over-pressurized nozzles create fine droplets and mist that evaporates or drifts from the field area.

An estimated 6,500 systems are considered to have incorrectly operating pressure gages, and therefore are most likely not being operated at the correct pressure. The cost to repair/replace gages on a 100 ac system is about $50 on the average. The estimated statewide costs for pressure gage replacement/repair is about $.33 million.

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.