Big Springs Water Users Association broke ground in May of 2016 on the first phase of the Big Springs Irrigation Ditch Conservation Project in Toston, Montana in southern Broadwater County. The project is part of a larger water conservation project that includes future phases that may extend for miles. This project served to conserve water lost estimated at 12.6 cubic feet per second (cfs), which is 4,500 acre-feet annually. Nearly 26% of the canal water was lost within the project section. This canal serves the entire Big Springs system of 2,646 acres.
Less than a year after the original open bid was announced, Big Springs Water Users Association was excited to break ground on this water conservation project. The original ditch was to be filled and abandoned from the existing concrete arch headgate and beyond.
The construction of Big Springs Irrigation Ditch relocated the current ditched system into a buried channel consistent with its historic route. This restoration effort will not only reduce pollution coming from nearby rail ditches, but also restore native vegetation and improve fish and wildlife habitat although the primary emphasis is irrigation management. The new canal will allow the agricultural community to apply the right amount of water at the optimal time.
To the nearby community, having a dedicated irrigation system in place to water the agricultural farmland is crucial for both their livelihood and their well-being. This buried irrigation canal provided a more efficient and effective use and conservation of the tributary spring water flowing from the nearby Missouri River. The contractor selected to oversee this project, George Rabel Excavation, reached out to their local supplier, HD Supply, to identify the right product. It would need to provide a service life of well over 75 years, be cost-effective and easy to install as well as provide the necessary hydraulics and retention to slowly release throughout the 3,050 linear foot canal. After review, they elected to utilize a DuroMaxx® steel reinforced polyethylene solution manufactured at the nearby Contech Engineered Solutions plant in Ogden, Utah. DuroMaxx® SRPE is manufactured with eighty (80) ksi steel reinforcing (SR) and pressure rated polyethylene (PE) resin. This unique combination of materials results in an extraordinarily strong and durable pipe which delivers high performance that will not creep or buckle yet is resistant to corrosion or abrasion.
Montana Rail Link donated significant time and materials to the project to stabilize the adjacent rail bed. Surplus track ballast met bedding requirements allowing cost and time effective delivery of over 10,000 CY of bedding and backfill material from MRL air-dump cars.
Water conveyance efficiency is essential in the improvement of this water distribution system to allow for better management of irrigation including the need to collect natural spring water near the inlet of the pipe. With that in mind, the first several feet of the 54-inch diameter DuroMaxx pipe was manufactured and delivered quickly to the site. A staging area was set up at the inlet end. The lightweight pipe was easy to install and the high performance (HP) bell and spigot joint were joined and guaranteed to maintain the required 15 psi. Adjacent to the DuroMaxx SRPE, a 4” perforated pipe was installed to run alongside the larger diameter pipe and collect additional spring water.
The close proximity of the ditch to the Missouri River and Montana Rail Link’s rail line introduced considerable bank instability putting both the rail and river at risk of damages. Rabel Excavation needed to protect and preserve the bank that ran alongside the Missouri River during construction and avoid interruptions to Montana Rail Link. The low profile of the DuroMaxx SRPE allowed the contractor to maintain a small construction footprint with minimal impact to the surrounding land during excavation. The smooth interior of the DuroMaxx® SRPE irrigation canal provided a pipe that is hydraulically efficient capable of Manning’s “n” values of 0.011 to 0.013 and allowed for minimum slope design for the 3,050 linear foot run.
The Big Springs Irrigation Ditch Conversation was funded, in part, by the DNRC Renewable Resources Grant and USBR WaterSMART Grant. The Renewable Resources Grant program rewards projects which conserve, manage, develop or preserve Montana's renewable resources while the WaterSMART grant selects projects, nationwide, that seek to conserve and use water more efficiently, increase the use of renewable energy, protect endangered species, or facilitate water markets.
The project was completed on time and within budget and provided an effective, new system to aid in the Broadwater Conservation project. Matt Barnes, PE, CFM from Morrison Maierle, Inc. commented, “In 2016, this project allowed the irrigators to deliver water to their entire system throughout irrigation season without water rationing for the first time in 55 years.”