Automated Meter Reading
The EAA Act stipulates that all municipal, industrial and irrigation water wells be classified as non-exempt wells, requiring a water withdrawal permit to be put in use and that any such well is required to be metered. The EAA is mandated to keep an accurate account of water being discharged from the aquifer. Meters that are integrated in the discharge line are used to monitor usage from permitted wells. Traditional meters have some disadvantages that make using a remote system more efficient. In 2004 the EAA began designing a remote meter to replace analog meters on a voluntary basis to agricultural permit holders.
An EAA permit classifies the use and quantity of water that can be withdrawn from the aquifer. Meters are installed on all permitted aquifer wells to keep track of the annual water usage. When the well pump is turned on and water begins to flow, it passes through an impeller within the meter which converts revolutions to its unit of measurement using a gear driven mechanical register not unlike a car odometer. The reading must be manually recorded at the well site.
Permit holders are required to record meter readings and submit them annually. EAA staff visits each permitted well on a yearly basis to check the meters to ensure they are operating correctly and to collect spot readings. During times of critical period, EAA rules require permit holders to reduce their water withdrawals from the aquifer and take monthly meter readings. Unfortunately, there are occasional discrepancies between the EAA and the permit holder’s data. These irregularities can be caused by human error, mechanical malfunctions or, in rare cases, tampering.
The EAA implemented an automated meter reading program (AMR) to mitigate the issues caused by meters. The EAA’s electronic meter is designed to limit human error, reduce manpower and eliminate mechanical malfunctions or tampering while maintaining the integrity and function of the original analog meter. A retrofitted, non-invasive sensor ring with a pulse output was developed by the EAA to convert existing meters into electronic meters. To make the conversion, the sensor ring is fitted around the existing mechanical register.
Early in the program, data generated by the electronic meter was transmitted via radio signal to a near-by EAA vehicle. Recently, this method has been replaced by transmitting the well data, in real time, to established communication towers. The well data is transmitted though the tower network and back to the EAA headquarters for further processing and storage. EAA staff has also put into use a programmable logic controller (PLC) that can store several months of data, allowing the EAA to include meters that are outside its wireless network as well as preventing the loss of data should a communication tower go offline.
To independently validate the equipment developed by EAA staff, the sensor ring was tested for accuracy by a third-party consultant. After a couple months of testing, it passed without issue. Many of the devices matched perfectly with their analog counterparts, while the older meters, tested within a +/- 0.25% margin of error.
This AMR program will effectively eliminate both the need for permit holders to take monthly readings at the well site and possibly the required annual inspection by EAA staff. The electronic meters are being successfully installed and tested on a volunteer basis by irrigators in the western portion of the EAA’s jurisdiction. Permit holders who would like to participate in the AMR program can contact the EAA Meter Team.