Section 02.03.03.650 - IRRIGATION SYSTEMSEquipment required for each type of irrigation system when chemigation is to be used includes: (3-15-22)
01.Sprinkler or Drip Irrigation. If chemicals are being chemigated through the sprinkler or drip irrigation system, the chemigator will verify that the system complies with either Subsection 650.01.a. or 650.01.b. plus the additionally specified equipment for each: (3-15-22) a. Irrigation Line Check Valve, (Section 665) ; with the following: (3-15-22) i. Automatic Low Pressure Drain, (Section 695) ; (3-15-22)ii. Inspection Port, (Section 690) ; (3-15-22)iii. Vacuum Relief Valve or a combination Air and Vacuum Relief Valve, (Section 685) ; (3-15-22)iv. Chemical Injection System, (Section 670) ; (3-15-22)v. Chemical Injection Line Shut Down (System Interlock), (Section 660) ; (3-15-22)b. Gooseneck Pipe Loop, Downhill and Over-A-Hill backflow prevention devices may be used For surface water, (Section 680) ; with (3-15-22) i. Chemical Injection System, (Section 670) ; (3-15-22)ii. Chemical Injection Line Shut Down (System Interlock), (Section 660). (3-15-22)02.Flood, Basin, Furrow, or Border Irrigation. If a chemical, including anhydrous ammonia, will be applied by flood, basin, furrow, or border chemigation through a gravity flow system, the chemigator will verify that the system uses a gravity flow dispensing system that meters the chemical into the water at the head of the field and downstream of a hydraulic discontinuity such as a drop structure or weir box to decrease potential for water source contamination from backflow if water flow stops. (3-15-22)03.Domestic Water Supply System Cross-Connected for Chemigation. Any irrigation system used for chemical application cross-connected to a domestic water supply system will be verified that the system contains either Subsection 650.03.a. or 650.03.b. plus all other additionally specified equipment for each; (3-15-22) a. Reduced Pressure Principle Backflow Prevention Assembly (RP) that: (3-15-22) i. Is located on the irrigation pipeline between the water supply pump and the point of chemical injection, and downstream from any domestic water supply diversion point. (3-15-22)ii. Keep contaminated water from flowing back into a domestic water supply system when some abnormality in the system causes pressure to be temporarily higher in the contaminated part of the system than in the domestic water supply system piping. (3-15-22)iii. Has been manufactured in full conformance with the American National Standards Institute (ANSI)/American Water Works Association (AWWA) ANSI/WWA C511 Standard for Reduced Pressure Principle Backflow Prevention Assemblies established by the AWWA; and have met completely the laboratory and field performance specifications of the Foundation for Cross-Connection Control and Hydraulic Research of the University of Southern California (USC FCCCHR); or an equivalent, Department-approved testing facility. (3-15-22)b. Chemical Injection System (Section 670) ; with either Subsection 650.03.b.i. or 650.03.b.ii. (3-15-22) i. Chemical Injection Line Shut Down (System Interlock), (Section 660) ; (3-15-22)ii. Air Gap (AG). The water from the domestic water supply system will be discharged into a reservoir tank prior to the chemical injection. An air gap will be at least double the diameter of the supply pipe measured vertically above the overflow rim of the vessel - in no case less than one (1) inch. Chemical injection will not occur upstream of the air gap; and (3-15-22)(a). Chemical Injection System, (Section 670) ; and (3-15-22)(b). Chemical Injection Line Shut Down (System Interlock), (Section 660). (3-15-22)Idaho Admin. Code r. 02.03.03.650