As summer winds down and we all anticipate the crispness of autumn and subsequent wintry season, the Nevada Irrigation District (NID) is ramping up maintenance efforts in anticipation of upcoming storms.
The preparatory work includes a diverse array of projects and tasks in advance of the change of seasons. A changing climate brings increased frequency and intensity of extreme weather-related events, and NID staff are preparing the system to keep the water flowing.
NID’s current work runs the gamut — our staff addresses the risk of localized flooding and debris damage in the canal system while accommodating safety protocols with rises in reservoir levels during the winter,
It’s a busy time, preparing for atmospheric changes in weather extremes have become increasingly common, and costly. Climate changes can wreak havoc with what we regard as historic weather patterns. The intensified storms can take a toll on aging infrastructure, much which is wooden or earthen canals that can be damaged by strong storms and increased flow volume.
The big picture: how a changing climate impacts our water supply and increases water delivery challenges
Climate change refers to long-term alteration in temperatures and weather patterns. As it pertains to the NID water delivery system, it relates to temperature and precipitation, either rain or snow that falls to the ground.
During the District’s Plan for Water process, a three-year deep-dive into the future of our water resources, modeling and simulations mapped out how a changing climate will affect the historic weather patterns and what that means for NID’s ability to address water supply and demand.
First, we must remember that NID’s water supply is derived entirely from surface runoff either in the form of snowmelt or rain. A large portion of the NID watershed is above the 5,000-foot elevation where snow falls during winter storms. This watershed acts as a natural reservoir, releasing runoff during the spring and summer months into the District’s conveyance system – canals and flumes – to be delivered to customers in the foothills.
Because the NID system was designed to take advantage of the snow cycle and the timing of the runoff, climate change has potential for a profound effect on the District’s operations and the reliability of water delivery.
The bottom line of the Plan for Water findings: modeling shows that in the future, and even now, the amount of precipitation in NID’s source watershed will remain much the same, but rising temperatures mean less snowpack that will melt sooner and faster. The benefit of a snowpack into the spring months means that water is stored longer on the mountain, and released as snowmelt runoff refilling lower level reservoirs as they deliver irrigation water to our customers.
As climate change continues, it will be marked by higher winter and spring temperatures. Projections indicate that some of what currently falls as snow will fall as rain, reducing the future average snowpack and snowmelt.
The Plan for Water process included expert scientific analyses and local public participation to develop a range of scenarios for NID’s Board of Directors to consider when determining the best ways to meet the community’s demand for water for the next 50 years.
Among those scenarios are increasing water storage to capture water to be used when it’s needed by customers. For example, on Sept. 25 the Board voted to proceed with exploring the potential of increasing storage at Rollins Reservoir and to discontinue activities in support of the proposed Centennial Reservoir. In their decision, directors cited the fundamental responsibility to provide a reliable future water supply to the community, cost and feasibility.
In embracing a “Rollins-raise” alternative, they agreed with the Plan for Water analysis, and determined the proposed Centennial Reservoir was not the most advantageous storage alternative for the District and its customers. The proposed location of a new dam between Rollins and Combie reservoirs is at a lower elevation in the watershed; this lower elevation limits the customers that would benefit from the new reservoir. Increasing storage at Rollins Reservoir would beneficially impact a greater number of customers with less impact to the environment.
Working to strengthen infrastructure ahead of winter storms
For the water year, which began on Oct. 1, The California Department of Water Resources predicts more extreme weather events throughout the season, following a record hot summer and a looming La Niña pattern.
Currently, on the ground, the work being done by NID crews is making the District’s water infrastructure as efficient as possible to reliably deliver water and also to withstand extreme weather events. Also, importantly, NID’s water managers are adapting the operations of the District’s distribution system to meet the challenges of a changing climate and harsher conditions.
Reinforcing the road to the D.S. Siphon Lane Pump Station
The District’s maintenance crew has been reinforcing an important berm that is the road to the D.S. Siphon pump station. This road and canal are located in very steep terrain and suffered damage last winter.
Located above Nevada City, the station gives NID the ability to pump water uphill into the Cascade Canal and also supply the Snow Mountain Canal in emergencies and other water outages. This was very important this year when unexpected damage through Lake Spaulding essentially cut off flows to NID foothill reservoirs. With no water replenishing the NID system, the pump station was essential to maintain deliveries to customers, and it ran around the clock.
Treatment Plant pond cleaning
NID crews are taking advantage of dry conditions and warmer weather to clean out reclaim ponds at the District’s water treatment plants.
The work is being completed at the Elizabeth George, Loma Rica, Lake of the Pines, North Auburn, Lake Wildwood, Smartsville plants.
During the water treatment process, sedimentation is filtered from the water, and backwashing water gets pumped or gravity fed to a series of reclaim ponds. There, the water can be filtered through the sand, and it leaves behind the solids when it dries out. The only time these ponds can be cleaned is at the end of summer before rain.
Hydroelectric crews prep powerhouses and dams
In September, the NID Hydropower department conducted its annual outage at Chicago Park and Dutch Flat powerhouses. The team also has been working in the high country to make storm preparations at Bowman Dam and the South Yuba Canal.
The efforts include:
- Hydro technicians are currently installing a new RTU (Remote Terminal Unit) for communicating remotely with Chicago Park Powerhouse, which has been more than a year in planning and design
- Compliance employees completed contracted vegetation removal within 15 feet of nearly a mile on the Chicago Park Flume
- At Bowman Reservoirs, crews are using a floating dock to make routine surface repairs on the dam as the lake elevation decreases
- A crew has been repairing flume floor joints and wall seals along the 8 miles of concrete box flumes which are up to 16 feet wide and 10 feet tall. The crew has hand mixed about 30,000 pounds of grout and concrete in the last month for multiple projects
Working on the ground
The NID maintenance department also is busy working on canals to clean them up and remove debris in preparation for storms.
Crews have been repairing and repaving damaged roads before cooler weather and moisture arrives.
Recently, district workers removed and repaired the DS Extension Pump, which has ran all summer due to the PG&E outage at Lake Spaulding. Understandably, the pump had low output.
In advance of winter storms, NID’s work is being completed to make sure water gets to you. We don’t know for certain what this winter will bring, but we can take some advice from Benjamin Franklin: “An ounce of prevention is worth a pound of cure.”
