LIT194-Handbook of TII.pdf - Diamond Head Sprinkler Supply

Maximum System Capacity Requirement – Total Area For Given Gallons Per DayThis formula may be used to to determine the area that can be irrigated if you know the gallonsavailable per day. This is the case in some water rationing systems or where a well capacity is thelimiting factor.Area = DU x Gallons0.62333 x Et o x K cWhere:Area = area to be irrigated in square feetDU = Distribution Uniformity or Irrigation EfficiencyGallons = gallons available from the water supply on the “Worst Case” dayEt o = evapotranspiration for the worst case scenarioK c = Crop Coefficient – use 1.0 if actual crop coefficient is not known0.62333 = constant for conversion of area, flow and inches per day, etc. into common unitsExample:The city has developed guidelines that allot a commercial project 36,000 gallons of water perday during an extended drought. The area being watered has a distribution uniformity of 60%,an average evapotranspiration rate of 0.22 inches per day and an average crop coefficient of 70%(0.70). How much of their project can be sustained with the city’s water allotment?Area = 0.60 x 36,0000.62333 x 0.22 x 0.70Area = 225,017 sq. ft. (approximately 5.2 acres)®Handbook of Technical Irrigation Information17