Current through Register Vol. 47, No. 17, September 10, 2024
6.1.
Any irrigation distribution system through which chemigation is performed,
except open discharge systems, shall be equipped with the mechanical devices
specified below. The equipment shall be permanently installed in accordance
with the manufacturer's specifications and at the location specified
therein.
6.2. Irrigation pipe check
valve
6.2.1. The irrigation pipeline check
valve shall be located in the pipeline between the irrigation pump and the
point of chemical injection into the irrigation pipeline. Its purpose is to
prevent reverse flow, which is a mixture of water and chemical draining or
siphoning back into the irrigation water source.
6.2.2. Irrigation systems which, as of July
1, 1989, were equipped with a properly located irrigation pipeline check valve
shall be considered in compliance with these Rules if the valve provides a seal
against reverse flow.
6.3. Vacuum relief valve
6.3.1. The vacuum relief valve shall be
located on the pipeline between the irrigation pump and the irrigation pipeline
check valve. Its purpose is to prevent creation of a vacuum in the pipeline and
possible reverse flow into the water source when the pump stops.
6.3.2. The vacuum relief valve shall be sized
in accordance with the manufacturer's specifications.
6.3.3. If the vacuum relief valve connection
will also serve as the inspection port, the permit holder will ensure removal
of the valve at the time of inspection. The inspection port shall be located on
the pipeline between the irrigation pump and the irrigation pipeline check
valve. The inspection port shall be situated in such a manner that the inlet to
the low pressure drain can be observed. A minimum four-inch or larger diameter
port is required. If a chemigation system has a vacuum relief valve of a
minimum two inch diameter, which was in place as of the effective date of these
Rules, and the irrigator will ensure its removal at the time of each
inspection, such valve may be used as the inspection port.
6.4. Drain
6.4.1. An automatic low-pressure drain shall
be located so as to drain any water-chemical mixture which may enter the
pipeline between the irrigation pump and the irrigation pipeline check valves
by reverse flow when the pump stops. When the pipeline water flow stops, the
drain valve shall automatically open. A tube, pipe or other conduit shall be
used to discharge the solution at least twenty feet downslope from the
irrigation water source or otherwise prevent it from collecting on the ground
surface around the well casing.
6.4.2. The drain valve shall be constructed
of corrosion resistant material or otherwise coated or protected to prevent
corrosion.
6.4.3. The drain shall
have an orifice of at least three-quarter inch diameter.
6.5. Chemical injection line check valve
6.5.1. The chemical injection line check
valve shall be located at the point of chemical injection into the irrigation
pipeline. Its purpose is to prevent flow of water from the irrigation system
into the chemical supply tank and to prevent gravity flow from the chemical
supply tank into the irrigation pipeline. The valve shall be constructed of
chemically resistant materials. The valve shall be designed to prevent water in
the irrigation pipeline under operating pressure from entering the chemical
injection line.
6.6.
Pumps
6.6.1. The irrigation pumping plant and
the chemical injection pump shall be interlocked so that if the pumping plant
stops, the injection pump will also stop. Its purpose is to prevent pumping
chemicals into the irrigation pipeline after the irrigation pump
stops.
6.7. Replacement
equipment shall meet specified requirements and in the case of irrigation
pipeline check valves, shall meet the following minimum requirements:
6.7.1. The valve body and all components
shall be constructed of corrosion resistant materials or otherwise coated or
protected to prevent corrosion;
6.7.2. The valve shall contain a sealing
mechanism designed to close prior to or at the moment water ceases to flow in
the downstream direction. This mechanism shall be either diaphragm-actuated by
hydraulic line pressure, spring loaded or weight loaded to provide a watertight
seal against reverse flow;
6.7.3.
All moving components of the valve shall be designed to prevent binding,
distortion or misalignment during water flow; and
6.7.4. The valve shall be designed to allow
repair and maintenance, including removal from the pipeline if required to
perform such work.
6.8.
The equipment required in these Rules and regulations shall be maintained in
working condition. When required, the equipment shall be repaired to its
originally designed condition.