City of Notus Irrigation System Replacement

The city of Notus, Idaho is seeking to renovate their irrigation system. Their current system is comprised of both open ditch/concrete channels and non-pressurized concrete piping with no information about the flows into or through the city. The city cites that the open ditch channels are difficult to maintain and are prone to erosion. In addition, the concrete channels and culverts within the aging irrigation system have been breached due to root intrusion and deteriorating concrete. Team LOCAL Engineering was tasked with designing a gravity-fed, concrete-lined, open channel system for the city. During the early stages of the design process, the team manually measured the flow rate of inflow channels and interviewed residents and city officials to determine demands on the system. The water rights (shares), vary from 1/50 cfs for Black Canyon to 1 acre-foot of water per season for Farmer’s Coop and are based on the acreage of each lot. Topographic maps are were utilized to identify the drainage and direction of flow for each channel, and Manning’s equation was used to estimate water flow rates throughout the irrigation system. With this information, we designed main channels through the city and small laterals to convey the water to each lot. Based on a soils report provided to us, concrete materials were recommended for both the lining and the shallow foundations for the channels. Precast concrete will be utilized. Environmental aspects are being evaluated to ensure compliance of chemical drainage to the river for aquatic life, and what course of action needs to be taken to ensure the river is not negatively impacted by the implementation of the project. The final design integrates all the considerations listed above to produce an effective and reliable irrigation system