Archives July 2015

The following article, republished from the August, 1964 edition of The Central Nebraska Irrigator, Central’s newsletter, tells about a rudimentary alarm system along Central’s Supply Canal, which was the precursor of today’s Supervisory Control and Data Acquisition (SCADA) system that monitors and controls water conveyance and hydroelectric generation throughout Central’s hydro-irrigation project.

The article was, in a way, clairvoyant. The writer may or may not have had some foreknowledge of what was to happen in the near future, but it also demonstrated that even in 1964, Central was ahead of its time.

Eight years after the article was written, the Gothenburg Control Center went into operation (in January, 1972) when remote supervisory control was established over the Diversion Dam, the Supply Canal’s hydroplants and control structures and the head gates of the irrigation canals. All are now monitored on computers at the Control Center by a supervisory control operator.

Control of Kingsley Hydro, NPPD’s Keystone Dam and the head gates of NPPD’s supply canal at the east end of Lake Ogallala were later added to the Control Center’s responsibilities because of the need for close coordination between the three components of the system to ensure proper flows into the canal and down river.

Communication is the key to such an automated system. The District has its own microwave system, supplemented by buried cable and VHF radio links. All information gathered at the remote terminal units (RTUs) is fed into the Control Center’s computers.

There are more than 1,800 alarm, control or telemetering points on the system which monitor and/or control functions of canal structures, pump stations, the three Supply Canal hydros and Kingsley Hydro.

The Control Center computer is programmed to receive data from the RTUs, check for alarm conditions and alert the operator to any abnormal readings. The operator’s control console includes a video screen that shows the current condition at any selected location on the system. Control functions are accomplished on a keyboard. The control room is manned around the clock every day of the year.

The automation enables Central to: 1) increase the generation of hydropower; 2) better manage the system under high-water conditions, i.e., sudden, heavy rain storms; 3) reduce the incidence of spills; 4) reduce maintenance needs on the canals as a result of better control of flows; and 5) reduce operating costs.

 From The Central Nebraska Irrigator, July/August, 1964

Electronic Equipment Will Provide Constant Check of Central’s 75-Mile Long Supply Canal

Gothenburg Division personnel in charge of operating Central’s 75.6-mile-long Supply Canal are sleeping a little better these days as an alarm system has been installed that will automatically notify the operator on duty at Jeffrey Hydroplant of a high- or low-water situation at any of four locations along the canal.

(Editor’s note:  The featured image on the blog page shows the transmission equipment located adjacent to water level detection equipment on the Supply Canal.)

Designed by Central’s Assistant Chief Engineer Ed Hamilton, the equipment was installed by the District’s electrical crew and members of the Gothenburg Division. The alarm systems have been installed at mile posts 5.1, 11.9, 31.2 and 35.9. These locations were considered as strategic or the most critical along the lengthy canal route.

Dale Craig, Jeffrey Plant operator, checks receiver equipment linked by radio to transmission equipment along the Supply Canal.

A water control gate is located at each of the four points and the alarms will tell the Jeffrey operator if water is high or low behind the gate or high or low below the gate.

The Jeffrey operator will also receive a visual and audio alarm should the power fail at any of the four locations.

The alarm equipment at the four canal sites includes electrodes and relays that are located in corrugated metal pipe wells upstream and downstream from the structure gates. These detect the high or low water levels. This equipment is connected to a radio transmitter with a tone encoder and timer that are mounted with a battery and battery charger as a power source.

When a high or low water level, or power failure occurs, the tone code is transmitted to the Jeffrey Power House by the radio transmitter and this code then switches on the proper light on a small panel at the power operator’s desk that indicates the location and type of trouble. A horn sounds at the same time.

The plant operator, hearing the horn, then checks the panel and determines by the light the location and type of trouble. He then silences the horn and contacts a canal patrolman or supervisor by phone and reports the trouble.

The four installations are the initial ones for the Supply Canal and it is expected that eight more locations will be included in the future.

A third phase in Central’s efforts to gain tight control of the Supply Canal will be automatic water recording equipment located at several points along the canal.

This equipment, by tone transmissions over the District’s Supply Canal telephone line, will give hourly readings of the canal water levels and gate openings.

The hydro plant operators will also be able to question this equipment at any time between the hourly readings.

When installed, the plant operator, after receiving a signal of high or low water conditions at any point on the canal, could then question the water recording equipment and find out exactly how high or low the water is. By questioning the water recorder at short intervals he could then determine if the trouble was of a temporary, self-correcting nature or if it is necessary to report the condition to a canal patrolman or his supervisor.

The information supplied by the alarm and recording equipment will give the Central District 24-hour coverage of its Supply Canal with instantaneous indications of canal trouble such as flooding from heavy rains, leaks or malfunctioning gates.

As the District gains more experience in the installation and operation of such electronic equipment, it is anticipated that similar systems will be worked into the hundreds of miles of irrigation canals owned and operated by the District.

The Central Nebraska Public Power and Irrigation District donated four portable water pumps this summer to fire departments in the Johnson Lake area.

The floating pumps will enable the volunteer fire departments – from Lexington, Elwood, Cozad and Eustis – to access water directly from lakes or canals in the vicinity of fires to supplement water available from tanker trucks.

The four pumps cost a total of about $13,000 and, according to Central Public Relations Advisor Tim Anderson, are kind of like insurance.

“We hope they never have to be used,” he said, “but they’ll be a nice addition to the fire fighters’ equipment in the event of a fire at the lake or another remote area where access to water is limited.”

The donation of the pumps came in the wake of a multiple-structure fire at Johnson Lake in 2013. One cabin was completely destroyed and two other cabins sustained extensive damage.

Anderson said the after-action report indicated that responding fire departments encountered difficulties with obtaining enough water to fight the fires.

He added that the pumps can be deployed quickly and, given the mutual aid agreement between the four fire departments, all four pumps could be used at the same time if necessary. Each pump can deliver about 300 gallons per minute.

“We thought – and the board of directors agreed — it was a good use of the lake improvement fund,” Anderson said, referring to money budgeted each year for improvements at Johnson Lake.

Employees of the U.S. Department of Agriculture’s Natural Resources Conservation Service (NRCS) toured Central’s hydro-irrigation project on July 14. Tour participants included Nebraska NRCS State Conservationist Craig Derickson of Lincoln and representatives from NRCS offices in Grand Island, Spencer, York, Lexington, Elwood and Minden.

Participants in the NRCS tour, including State Conservationist Craig Derickson (at left) listen to an explanation of how data from an automated weather station is used in the E67 irrigation management/telemetry project.

The participants assembled at Central’s office in Holdrege, then headed to several sites within the District’s irrigated area, including stops showing pivot and sub-surface drip irrigation installations on Central’s system, and automated check gate structures along the main canals. One of the highlights in the morning was a stop at a site within the E-67 Canal area where Central’s Conservation Director Marcia Trompke explained the workings of the new telemetry project.

The telemetry project began this spring with the installation of radios, remote terminal units (mini-computers that relay data), and weather stations to serve one-third of the turnouts on the E-67 system. Over the next two years, the remaining turnouts will be similarly equipped.

This project’s objective is to gather irrigation water use and environmental data to support Central’s irrigation water management, water conservation and water quality goals. The project involves the cooperation of Central’s customers irrigating about 5,800 acres in the E67 area north of Elwood and Smithfield.

The project will collect irrigation water use data from irrigation flow meters and weather monitoring sensors crucial to irrigation management. Data will be available in real time to Central and individual irrigators through digital applications to help customers make sound irrigation management decisions.

The project is partially funded by a grant from the Nebraska Environmental Trust Fund and includes partnerships with UNL Extension for educational services and the McCrometer Co., which is providing flow meters, technical expertise and equipment installation training.

The tour continued on to the Gothenburg Control Center where Electrical Superintendent Devin Brundage explained Central’s highly automated system for monitoring and controlling water all the way through its hydro-irrigation project.

After lunch at Gothenburg’s Nebraska Barn & Grill restaurant, courtesy of Central, the group then headed to the Lake McConaughy Water Interpretive Center where the participants viewed a video about the construction of Kingsley Dam and then toured the reservoir’s control structures. Kingsley Dam Foreman Nate Nielsen then explained the workings of the Kingsley Hydroplant, which was generating 30 megawatts of clean, renewable hydroelectric power at the time.

According to Nate Garrett, P.E., NRCS area engineer in Grand Island, who arranged the tour, “It was an opportunity for us to see one of Nebraska’s premier ag-engineering accomplishments and to network with one of our irrigation partners in the central part of the state. It was a fantastic tour.”

Tessa Combs, an NRCS intern who hails from Kentucky and who is working in Grand Island this summer, said, “It was really helpful to actually see the facilities and how they operate, instead of just reading about it or trying to figure out the complexities of the project by looking at a map.”

Central routinely offers tours of its hydro-irrigation project to organizations and groups throughout Nebraska, as well as groups from other states and foreign countries. If your group is interested in a one- or two-day tour of the sprawling project, contact Public Relations Coordinator Jeff Buettner at (308) 995-8601. We’ll set a date for you!

When June came to a close, inflows to Lake McConaughy during the month had entered the records books as the fifth highest since storage began at the reservoir in 1941.

Inflows totaled 335,138 acre-feet (a-f) for the month. The five highest inflow totals for June:

Wet Junes are not unprecedented, nor particularly unusual. Historically, peak inflows typically occur in October – following the end of irrigation season – and June, often because of spring precipitation and snowmelt runoff.

However, this June’s inflows were more than four times the historical median of 74,924 a-f and were somewhat unexpected. Inflows to Lake McConaughy in March were only 85 percent of the historical median of 75,959 a-f, and April’s inflows were 82 percent of “normal.” Projections, upstream storage conditions, and weather patterns did not indicate the likelihood of much of an uptick in inflows, but frequent and sometimes heavy precipitation in May altered the trend. Inflows during May surged to 163,429 a-f, almost two-and-a-half times more than the historical median, and well-above average inflows continued throughout the month of June.

Lake McConaughy at elevation 3263.3 feet on July 1, 2015

The much needed inflows raised Lake McConaughy’s storage level to elevation 3,263.1 feet on June 30, less than two feet from the maximum operating level that was established in 1974. The maximum level was put in place after high winds during a 1972 storm caused significant wave damage to the face of Kingsley Dam. The storm occurred when the reservoir’s elevation was above 3,266 feet; maximum designed elevation at the time was 3,270 feet.

Just in case, Central recently sought and received a waiver from the Federal Energy Regulatory Commission to exceed the 3,265.0 elevation by up to two feet if necessary to hold back North Platte River water and prevent it from contributing to flooding conditions in stretches of the central Platte River being caused by high flows in the South Platte River.

July arrived with the typical hot, dry conditions (although it was raining again as this post was being written), and flows in both the North Platte and South Platte rivers are beginning to recede. Irrigation demand is also picking up slightly, although growers will monitor soil moisture conditions before irrigating. Abundant soil moisture often inhibit good root development, simply because crops’ roots don’t have to go far to find water.

As the rivers and inflows begin to recede, it now appears unlikely that Central will need to exceed its normal maximum elevation. What does appear likely is that Lake McConaughy will be in excellent shape in terms of next year’s water supply.