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Measurement Plans and Measurement Variances

Measurement Plans and Measurement Variances. Upper Wood Rivers Water Measurement District Flow Meter Workshop January 27, 2012. Why Measurement Plans?. Confirms owner or operator of a well

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Measurement Plans and Measurement Variances

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  1. Measurement PlansandMeasurement Variances Upper Wood Rivers Water Measurement District Flow Meter Workshop January 27, 2012

  2. Why Measurement Plans? • Confirms owner or operator of a well • Documents a water user’s intentions to install a standard magnetic flow meter, or provides opportunity to request a variance of the mag requirement • Allows hydrographer or IDWR to make an initial evaluation of a diversion system for variance approval or denial • Ensures correct installation of flow meters

  3. Acceptable Standard Flow Meters • A full-profile magnetic meter which appears on IDWR’s List of Approved Electromagnetic Meters • Any other full profile magnetic meter which meets IDWR’s minimum criteria (users bears the risk the meter will perform as rated) Minimum Criteria: • Flow range 0.1 – 33 feet per second • Manufacturer accuracy ± 2%, repeatability ± 0.5% of reading • Display which registers both rate and totalized volume • Display must be programmable, non-resettable, and have sufficient number of display digits and units of volume that the totalizer will not “roll over” within a two year period. Insertable magnetic flow meters are NOT standard meters and use must be approved through the variance process

  4. Variances to the Magnetic Meter Requirement • Development of a Power Consumption Coefficient (PCC), a ratio of power usage to water withdrawal (qualifying irrigation diversions only). • Use of an hour meter or time clock (qualifying diversions only). • Use of an existing operating flow meter (installed prior to the date of the measurement order) if that meter meets accuracy tests. • Use of an acceptable non-standard flow meter where it can be shown that installation of the standard meter would be burdensome (diversions with pipe sizes >12”, other special cases). Acceptable variances have NOT YET been fully determined for small users.

  5. Variances to the Magnetic Meter Requirement 1. Power Consumption Coefficient (PCC) - a ratio of power usage to water withdrawal. PCC may only be used where this ratio is constant. PCC is invalid under any of the following conditions: • the presence of secondary loads on the power meter UNLESS they always run with the well. • artesian flow, variable frequency drives or non-electrical energy sources which can’t be reliably measured • variable diversion rates and/or pressures, or changing water levels over the irrigation season

  6. How Many Pumps can you Count? 1 4 3 2

  7. Variances to the Magnetic Meter Requirement 2. Hour meters or time clocks – measure the total time the pump has operated over the season. This method is suitable for pumped wells which open-discharge into a pond, ditch, or cistern • Flow discharge must be steady and must not increase or decrease through the season • Flow must be measured by the hydrographer • Pump must not be throttled • Clock must be wired into the main pump control, and must be mounted on the outside of the panel.

  8. Variances to the Magnetic Meter Requirement 3. Use of an existing operating flow meter. Meter must have been installed prior to the date of the measurement order • Existing meters will be field tested and must be accurate to ±10% of actual rate and volume when compared to a certified portable flow meter • Meter must be installed properly, have a non-resettable totalizer and suitable units of rate and volume • If the meter fails, or ceases meeting the accuracy test, it must be replaced with a magnetic meter

  9. Variances to the Magnetic Meter Requirement 4. Use of an acceptable non-standard flow meter with an approved variance only. For diversions with pipe sizes > 12: • Insertable magnetic meters – limited to those systems where flow is not variable • Vortex meters – highly accurate but expensive, usually reserved for industrial applications • Ultrasonic or acoustic doppler meters – accurate over a wide range of flow in very large pipe Under consideration for small users on pipe sizes ≤ 2”: • Ultrasonic clamp-on or spooled types • Positive displacement or mutating disk (aka city service meters)

  10. So, how do I complete my plan??

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