CONSTRUCTION SPECIFICATON

NE- 209 IRRIGATION FLOWMETER

1\. SCOPE

The work shall consist of furnishing, installing and testing irrigation
flowmeter(s) at the location(s) shown on the attached plans or data
sheets. This shall include the meter and all necessary appurtenances,
such as couplers, joints, gaskets, and elbows.

2\. MATERIALS

The meter shall be of the type and brand specified, or an approved
equivalent. The meter shall be capable of measuring within an accuracy
of +/- 2% of actual flow. Appurtenances needed to attach the meter to
the existing pipeline shall be of a pressure rating equal to or greater
than the existing pipeline or in excess of the maximum anticipated
operation pressure of the existing pipeline, including surge pressures
capable of withstanding the operating pressure of the pipeline without
leaks or creating an obstruction that could affect the operation of the
meter. Meters installed in an underground pipeline shall be supplied
with a meter pit or a remote sensing monitor. The pit dimension shall
allow a minimum of three inches of space horizontally from the flanged
ends of the meter to the pit wall, but the total width of the meter pit
shall not be less than 3 feet in any case. The pit shall be constructed
with a standard pre-cast concrete manhole or concrete culvert section,
16-gauge minimum corrugated metal pipe, or 4" nominal treated lumber.
Notches shall be field cut to allow the pit walls to slip over the pipe
so that the bottom of the pit is at the bottom of the pipe. In lieu of a
meter pit, an extension may be installed which connects the meter sensor
to an above ground readout.

3\. INSTALLATION and OPERATION

The manufacturer\'s recommendations for the installation of the
flowmeter shall be obtained prior to installation, and a copy shall be
supplied to the NRCS Technician or Engineer. The recommendations shall
include the requirements for straight pipe distance both upstream and
downstream of the meter. These distances shall be detailed for various
appurtenances, such as elbows, valves, sudden enlargements, and
contractions. The meter shall be placed in the pipe in a position, which
is correct for the pipe diameter and wall thickness. In the absence of
manufacturer's recommendations for straight pipe, distance up and
downstream of the meter the general requirements for the location of the
meter are as follows:

NON-JETTING FLOW CONDITIONS

[All meters except vortex meters]{.underline}

Without straightening vanes: Upstream \-- 10 diameters

> Downstream --- 2 diameters

With straightening vanes: Upstream --- 5 diameters

> Downstream --- 2 diameters

NON-JETTING FLOW CONDITIONS

[Vortex meters]{.underline}

Without straightening vanes: Upstream --- 10 diameters

> Downstream --- 5 diameters

With straightening vanes: Upstream --- 5 diameters

> Downstream --- 5 diameters

JETTING FLOW CONDITIONS

[All meters except vortex meters]{.underline}

Without straightening vanes: Upstream \-- 20 diameters

> Downstream --- 2 diameters

With straightening vanes: Upstream --- 10 diameters

> Downstream --- 2 diameters

[Vortex meters]{.underline}

Without straightening vanes: Upstream --- 20 diameters

> Downstream --- 5 diameters

With straightening vanes: Upstream --- 10 diameters

> Downstream --- 5 diameters

If the Technician or Engineer determines that there is not full pipe
flow at the meter site, a hump shall be installed downstream of the
meter. The top of the hump shall be at least one-pipe diameter above the
top of the line. Air, pressure, and vacuum relief valves may be
installed on the hump, if they are needed for the proper functioning of
the pipeline system.

\"HUMP\" shall be defined as a rise in the outlet pipe on a given angle
(usually 45 degrees) to a point at which the bottom of the downstream
portion of the outlet pipe is higher than the top of the upstream
portion of the outlet pipe. After a short distance (1 to 2 feet), the
pipe may be angled back down to the preceding pipeline gradeline.

The installer will insure that the flowmeter is functioning properly at
the time of installation. The meter shall be examined with water flow
through the pipeline to determine if the meter is functioning properly
and accurately measuring water. If operation problems, abnormal
fluctuations in reading, or other deficiencies occur, the installation
shall be re-evaluated and the cause of the problem and/or deficiencies
corrected.

The manufacturer's recommendations for maintenance shall be obtained and
followed. It is recommended that the meter be removed at the end of the
irrigation season and stored indoors.