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The Hemphill Diversion Structure Project: public invited to review and comment on alternatives

September 4, 2020

The Initial Study for the Hemphill Diversion Structure Project has been released, and the public is invited to review alternatives to allow for fish passage beyond the structure on Auburn Ravine near Lincoln.

The 30-day review period for the Initial Study began on Sept. 3 and will end on Monday Oct. 5. During this period, the public can provide comments orally during a scoping meeting and through written submissions.

The Nevada Irrigation District (NID) diverts water from the Auburn Ravine into the Hemphill Canal for delivery to raw water customers. The proposed project aims to remove the old concrete structure, used by the District since 1933. The Initial Study includes analysis of four potential alternatives to allow for fish passage beyond the diversion structure. These include: 1) Riverbank Infiltration Gallery Alternative, 2) Fish Passage Alternative, 3) Pipeline Alternative, and 4) Abandonment of Hemphill Canal Alternative.

The Initial Study is available for download here.

A public scoping meeting is scheduled for Monday, Sept. 21 from 4-6 pm. A brief presentation will begin at 4 pm. Afterward comments will be accepted until the meeting concludes.

Additionally, written comments can be sent to Kris Stepanian, Board Secretary, at Nevada Irrigation District, 1036 West Main Street, Grass Valley, CA 95945 or via email at Please indicate “Hemphill Diversion Structure Project” as the subject matter, and provide contact information.

The Initial Study was prepared to satisfy the California Environmental Quality Act (CEQA) that requires all state and local government agencies to consider the environmental consequences of their projects. A CEQA Initial Study is generally used to determine which CEQA document is appropriate for a Project (Negative Declaration, Mitigated Negative Declaration, or Environmental Impact Report [EIR]).

NID has already determined that an EIR will be prepared for the Hemphill Diversion Structure Project. The purpose of the Initial Study is to eliminate areas listed as having “no impact” or “less than significant impact” from further consideration in the EIR.

The EIR will include a full analysis of all four alternatives to provide the NID Board of Directors with information necessary to approve their preferred alternative.

Here is a brief summary of each alternative:

  • Alternative 1 would include removal of the Hemphill Diversion Structure and construction of an infiltration gallery within the north or south bank of Auburn Ravine to facilitate continued water deliveries to Hemphill Canal. The gallery is anticipated to be located about 75 feet downstream of the existing diversion structure.
  • Alternative 2 would include the potential replacement or alteration of the Hemphill Diversion Structure to accommodate a fish ladder within the Auburn Ravine. The fish ladder is anticipated to be located adjacent to or on the existing diversion structure.
  • Alternative 3 would remove the existing diversion structure and construct an underground pipeline extending from existing NID facilities on Gold Hill Road to Hemphill Canal. Construction of Alternative 3 would include installation of a 24-inch raw water pipeline in the Fruitvale Road, Fowler Road and Virginiatown Road rights-of-way (ROWs). This alternative would also include an above-ground stream crossing downstream and west of the existing diversion. The majority of the pipeline is within Placer County jurisdiction for encroachment permits.
  • Alternative 4 would remove the Hemphill Diversion Structure and decommission Hemphill Canal and would include the Hemphill Canal as it travels through Turkey Creek Golf Course as well as adjacent land to the west. Additionally, this alternative would affect existing Hemphill Canal raw water users within the City of Lincoln.

For more information about the Project, click here.

The Initial Study is available for download, click here.

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