PHOENIX -- The Salt River Project (SRP), headquartered in Phoenix, Arizona, has managed their geographically dispersed water and power infrastructure since the turn of the century, gradually building more technology into the system. However, up until three years ago, the utility was still driving trucks to many of their remote desert and mountain water transmission sites to collect information from water flow meters. This has all changed now that they are collecting data with the world's first commercial Low Earth Orbiting (LEO) satellite data communication system.
SRP is one of Arizona's largest water and power utility agencies and the third-largest public utility in the entire U.S. They have the distinction of being the first multipurpose water reclamation operation established through the provisions of the National Reclamation Act of 1902. Recently they have distinguished themselves as the first power utility in the country to utilize LEO satellites for remote waterflow monitoring. SRP handles the monitoring with SPATIA, a data collection, communication, and information processing package they developed.
With 4,100 employees, SRP delivers nearly one million acre-feet of water to a massive 240,000-acre service area in the metropolitan and suburban Phoenix region. In addition, they cooperatively manage a 13,000 square-mile watershed -- a natural drainage area in the mountains northeast of Phoenix. This watershed feeds the Salt and Verde rivers that flow into the SRP reservoir system to feed an intricate 1,265-mile network of canals, laterals, and small channels. About 30 percent of their water flows to agricultural users, and the other 70 percent to municipal and industrial users.
Given such an extensive system, monitoring water flow accurately becomes extremely important. Any delays in gathering information could cause administrative problems, as well as operational difficulties. Additionally, errors in quantifying flows will cause data collection to be flawed, having a disruptive ripple effect on statistical reporting and historical trending.
SRP's satellite-based data. communication system begins with SPATIA's connection to waterflow meters at 30 different application sites all over the agency's area of responsibility. Ten of these meters are supplied by Water Specialties, located in Porterville, California -- the largest manufacturer of propeller meters in the world.
The Water Specialties meters at SRP are propeller meters, connected to deep well pumps in the desert and some urban constituent pumps. Flowrate data displays out on an LCD screen offering the present rate of flow and the total flow-to-date in gallons per minute or other designations. The built-in indicator-totalizer connects to a transmitting unit designed for sending SPATIA'S proprietary signal to a satellite.
ORBCOMM® supports the satellite-based data communications system from their facility in Reston, Virginia. The pioneering company first launched LEO satellites in 1995, offering commercial service to a broad clientele. For the remote gathering of its waterflow data, SRP utilizes its SPATIA package, a bundled network of earth-to-satellite-to-earth communications backend data support functions.
SRP's SPATIA communication/data logging device, a VHF radio in a weather-resistant fiberglass case, is powered by 12 volts DC from a solar array, and has a 7-amp hour back-up battery. The radio communicator sends and receives messages to and from LEO satellites circling relatively close to the earth. Once the satellite receives the message, it's carried in it's internal computer buffer until it locates a ground Earth Station.
With geo-stationary (also called geo-synchronous) types of satellite systems, one satellite revolves around the earth always staying above the designated tracking site. On the other hand, LEO satellites have multiple craft orbiting completely around the earth in orbits that overlap the entire globe. ORBCOMM has a total of 28 satellites. Consequently, at least one satellite is always within reach of a ground communication device. If trouble occurs in one satellite, another one will take over to transmit and receive its signals. Surprisingly, only a low 5 watts of power is needed to reach the satellite, since they fly in a very low 500 mile orbit above the earth.
Geo-synchronous satellites fly at a very high 23,000 miles above the earth, and the footprint that they transmit back is quite large. Conversely, the low-flying LEO satellites have a very small footprint on earth, and must therefore have ground Earth Stations in strategic locations to send and receive signals from the satellites.
ORBCOMM has four earth stations situated in four states: Washington, Arizona, Georgia, and New York. These stations receive rebounded signals from satellites in the region and then send them by landline to the Network Control Center in Virginia, where they are routed to a specific client in a particular region of the country.
For example, Gateway Earth Station in St. Johns, Arizona, sends the signal via a dedicated, fiber-optic telecommunication line to the network control center in Virginia, where the data is encapsulated and then routed via frame-relayed format back to SRP in Phoenix by dedicated landline. At the SPATIA Data Center in Phoenix, the data is posted on the SPATIA website. The data's full round trip, from the time it leaves the waterflow meter until it gets back to Phoenix, happens in two minutes or less.
The information that the SPATIA client receives can be configured in any way or for any purpose deemed necessary. For SRP's purposes, the data is translated into graphs, charts, tables, or text that allow administrative or technical staff members to analyze collected information. Examples of available data are: graphs detailing water use, water flows, storage basin volumes, and water quality monitoring. Besides being viewed in HTML on the SPATIA website, this information can be transmitted via e-mail (SMTP), as ASCII text files, MV-90 for energy applications, or raw data via FTP.
By accessing the website, it's even possible to control a piece of equipment at a remote field location, like a water pump or transmission valve. By merely sending a simple SPATIA encoded e-mail message to the Control Center in Virginia, data is transmitted to the satellite orbiting over the southwest region, which then sends the data back to the designated regional Earth Station. The Earth Station then forwards the feed via a twisted pair cable to a programmable logic controller (PLC) on the transmission line telling it to open or close a particular valve. Once again, it all happens within a few minutes.
Overall, what a water and power utility, or any business, hopes to achieve with new technology are savings in terms of time, effort, and money. While Supervisory Control and Data Acquisition (SCADA) systems were a gigantic leap in technology that brought increased returns-on-investment, the SPATIA system goes one step further.
"We go through what any business or government agency goes through, and that's trying to control costs," Ester said. "There's a definite dollar savings after operating a SCADA system using cell-phone coverage or fixed-wire modems for sending and receiving data. However, the real value that we get from the new system is almost-immediate access to data, since all of our back office functions are now done in real time. Whereas we previously had a lot of clerical people tabulating and processing for all of our collected data, we can now utilize our world force much more efficiently," Ester concluded.
Ester said that the agency can now process information without all of the data collection and data entry that was formerly necessary. They now produce month-end reports with the click of a mouse button. Since SRP operates in many inter-governmental cooperative arrangements, Ester says they'll eventually be using the new system for monitoring rivers, watersheds, and other recharge basins with a multitude of companies and agencies. The accuracy of their data has paved the way for these partnerships.
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