New Zealand’s Otago region produces top-quality fruit, wines, crops, and livestock, and to do that, it needs water. In recent years, there have been persistent disagreements between the central government, the regional council, environmental interests, and community members about how to manage water in the catchment. Points of contention include how to distribute stored water, how to pay for water infrastructure, and what levels of flow must be preserved in the rivers. Gary Kelliher has addressed these issues from many angles. Himself a farmer, he has also served as the chair of an irrigation scheme and the deputy chair of an independent, catchment-wide strategy group, and he is currently a member of the Otago Regional Council (ORC). In this interview, he tells us about the many interests on the river and how they can find win-win solutions to their problems.
Irrigation Leader: Please tell us about your work in New Zealand.
Paul Meeks: We have done quite a lot of debris control and public safety work in New Zealand. Our first international project was in Australia for the Snowy River hydroelectric scheme following devastating fires around 2002. Shortly thereafter, power companies in New Zealand got wind of our waterway barriers and requested that we provide debris control barriers and safety barriers at their dams. We have had a good relationship, and today, we have booms and buoys all over New Zealand.
In 2017, the catchment area above Lake Matahina experienced a near probable maximum flood event. The result was a sudden, massive influx of debris. The TUFFBOOM barriers installed by Trustpower the previous year prevented the debris from reaching and blocking the floodgates and water intakes. Although it took 6 weeks to remove all the debris from the reservoir, the utility never lost a single minute of generation because the booms kept all the debris away from critical areas. Trustpower estimates this saved it more than NZ$800,000 (US$564,920) in prevented generational losses alone. The client called us afterward to say that it could not have been more pleased with the performance. This was a flood of record, yet the booms prevented the dam from overtopping by keeping the debris away from the spillgates, allowing them to spill properly. The booms also kept all the debris away from the water intake. Not only was our client able to continue spilling water during a critical period, it was able to continue to generate power. It said that this was a huge payback that justified having booms around these dams and power plants.
Irrigation Leader: How many projects do you think you’ve done in New Zealand?
Paul Meeks: I used to know the numbers, but it’s quite a lot of installs.
Irrigation Leader: What is your message to potential clients in New Zealand?
Paul Meeks: New Zealand is a wonderful country with great water resources for irrigation, water supply, and hydroelectric power generation. With dam ownership, however, comes a responsibility to assure the safety of these dams—the structural safety, of course, but also the safe use of these water resources from a public safety perspective. Much of the work on public safety around dams being done internationally relies on the dedicated work of dam engineers from New Zealand who serve on important committees with the International Commission on Large Dams. In addition to public safety, the safe operation of a dam includes preventing the blockage of water intakes and floodgates by debris or trash. As the folks at Matahina discovered, a sudden debris influx can have significant effects on the safety of the dam and on revenues. We encourage dam owners to consider how a debris control system can improve their operational reliability, reduce dam safety risks, and lower risks to the members of the public who recreate around these structures.
Irrigation Leader: Would you tell us about the work that you’ve done on fish barriers?
Paul Meeks: Our first fish barrier project was a massive system for the U.S. Army Corps of Engineers at the Bonneville Dam along the Columbia River in Washington State. Since that project, we’ve been highly successful in this realm. There are different types of fish barriers, including electronic barriers and physical barriers. We design physical fish guidance barriers. When I describe our work to a layperson, I tell them that we place a floating wall in a river or reservoir, usually 3 meters deep. The fish approach this wall and follow the current to a bypass or collection system. We prevent them from turning into sushi! Of course, the science behind these systems is quite complex and requires not just an understanding of barrier design but also a detailed understanding of fish and fish behavior. Placing a wall in the water sounds simple, but where we locate that barrier, what angle it is placed at, and how deep it is are all critical to whether it works or not. We have a fisheries biologist on staff who works closely with our engineers and clients to guide and inform us on the design as it relates to a particular species of fish. The success of fish guidance systems really comes down to locating and angling your boom to optimize the water’s surface velocity. The fish are going to follow the velocity. We see a lot of people go out and install fish guidance systems without spending the necessary time on velocities or positioning, and they end up getting an ineffective barrier that must be revisited and reconfigured multiple times to get it to function properly. We take time up front to understand the flows completely so that our clients’ guidance structures will achieve the ultimate level of success. In the United States, guidance systems are judged partially on how little water needs to be sent over the dam versus through irrigation channels or through turbines. If you’re passing water instead of putting it through a turbine or an irrigation canal, you’re basically throwing money away. We minimize the amount of water that has to be passed.