The Combie and Ophir II & III Siphon Replacement Project (Project) involves the replacement of three existing underground siphon pipelines.   The Orr Creek, Dry Creek, and Rock Creek siphons are each over fifty years old, are nearing the end of their useful life, and require resizing to address approved future flow needs.  The siphons are part of NID’s Combie and Ophir 2 & 3 raw water delivery system.  The first replacement will be the Orr Creek Siphon, which is currently under design and will be replaced in the fall of this year,

Notice of Determination and Board of Directors Approval of the Combie-Ophir II & III Siphon Replacement Project and the Mitigation, Monitoring, and Reporting Plan

Combie-Ophir II & III Siphon Replacement Project Final Mitigated Negative Declaration and Initial Study with Appendices

Draft Initial Study and Mitigated Negative Declaration for the Nevada Irrigation District Combie-Ophir II& III Siphon Replacement Project

Notice of Intent to Adopt a Mitigated Negative Declaration and Initial Study

The District adopted the Mitigated Negative Declaration and Initial Study on June 26, 2024. 

The District's Board of Directors awarded a construction contract to C & D Contractors at the August 28, 2024, Board Meeting.

CONSTRUCTION UPDATE:

As of February 2026, construction of the Orr Creek Siphon replacement project is complete.

Construction of the Orr Creek Siphon replacement is expected to begin in  May, 2025. 

Location Maps:
Orr Creek Siphon

Dry Creek Siphon

Rock Creek Siphon