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Construction Projects

Hell Hole Dam Core Raise

Project Description

Hell Hole Dam is a zoned rock and earth fill structure, which consists of an impervious clay core that holds back the water; two filter zones (of fine and coarse material) that keep the clay core in place; and rockfill slopes that create a “shell” on both the downstream and upstream sides. PCWA is raising the dam core to permit the installation of a gate on the spillway that will allow us to capture an additional 6 feet of water depth (about 6,000 acre-feet) during wet years. Most of the additional water will be released over the spillway in a controlled manner to enhance environmental and recreational flows in the Rubicon River downstream; however, the Agency will be able to use some of the water to increase hydropower generation.

Project Schedule

The project is currently in progress and expected to conclude in October of 2020.

Photo of Hell Hole Dam construction
Hell Hole Dam core raise construction (click to enlarge)

Foothill Raw Water Pipeline Phase 2 Project

About Project

This project includes raw water and treated water pipelines that connect to existing pipelines located south of I-80, then traverse south, primarily on private property, crossing Indian Hill Road and Glenview Road, before traveling along Powerhouse Road and terminating at the Foothill WTP.

The Foothill Raw Water Pipelines - Phase 2 Project will provide the Placer County Water Agency (PCWA) a means to deliver raw water from the American River to the Foothill Water Treatment Plant (WTP) independently of the normal supply of raw water from PG&E’s South Canal in an emergency or during PG&E’s annual fall outage; when the Agency’s raw water supply is shut down for annual maintenance. The Project includes the ability to transfer treated drinking water from the future Ophir WTP to the Foothill WTP. The project also gives PCWA a means for supplementing the current PG&E raw water allotment to meet its expanding service area demands.


The Foothill Raw Water Pipelines - Phase 2 project includes two primary components, 1) the completion of the Foothill Raw Water Pipeline and 2) construction of a treated water pipeline and related facilities to deliver treated water from the future Ophir Road Water Treatment Plant to the Agency’s Foothill/Sunset System. The Project consists of:

  • 7,300-feet of 12-inch, 18-inch and 24-inch treated water pipeline
  • 650-feet of 45-inch pipe in Ophir Road and removal of two interties
  • 7,866-feet of 33-inch to 39-inch pipeline from Dutch Ravine to the Foothill WTP, and Standpipe
  • 160-feet of 60-inch casing - open shield pipe jacking – UPRR crossing
  • Stand pipe overflow, cleaning railroad tunnel, and drain
  • Energy dissipation structure at Dutch Ravine
  • Energy dissipation structures at the Foothill WTP
  • Pump Station Improvements at Ophir Road
  • Fiber Optic System
  • 12-Inch Intertie at the Newcastle Tank
Project Schedule

The project is scheduled to begin construction in February 2020 and complete October 2021.

Upcoming Work (updated October 15, 2020)

The Contractor will be performing the following construction activities in the next few weeks:

  • Cleaning up work areas, and installing permanent fence.

  • Installing stormwater pollution prevention material and hydroseed in anticipation of winter in areas where the raw water and treated water pipe have been installed.

  • Work through roadways, and traffic delays, are not anticipated in October.

  • Ongoing activities to construct the Energy Dissipation Station at the Foothill Water Treatment Plant, continue installation of esthetic concrete masonry units and glass blocks on walls. Installation of electrical, plumbing and mechanical is ongoing.

  • Ongoing activities to construct the Dutch Ravine Energy Dissipation Structure at PCWA property located on Hillview Lane. Installation of electrical, plumbing and mechanical is ongoing. Concrete basement/pit walls are complete.

  • Grading for the Hydraulic Control Standpipe that will be located adjacent to Indian Hill Road.

  • Installation of the 36-inch and 42-inch overflow pipe from the Hydraulic Control Standpipe to the railroad tracks. .

For questions regarding this project, contact:

Project Manager / Engineer
Heather Knutson
Phone: (530) 823-4951

Map Figure of Foothill Raw Water Pipeline Phase 2 Project
Foothill Raw Water Project Components (click image to enlarge)
download pdf

Alta Loop Pipeline – Cable And Powerhouse Rd

Project Description

The project will consist of replacing the existing 4” steel distribution water main within Cable Road, Alta Power House Road, and Timber (red line). The main has experienced several breaks throughout the years and is at the end of its useful life. The pipe that goes from Brown Road south east through several properties to Alta Bonnynook Road may be replaced by installing a main in Alta Power House Road (yellow line). All existing services will be replaced and/or reconnected.

A new water main (green) will also be installed along Cable Road beginning at the intersection of Cable Road and Timber Lane going east connecting to the existing 10” distribution main at the east end of Cable Road. A pressure reducing station (PRS) will be included to connect two distinct pressure zones. The purpose of the new line is to increase the reliability of service by providing redundancy to a portion of the system.

Project Schedule
  • Survey, geotechnical exploration, and other information gathering – 2019
  • Design – 2019-2020
  • Advertise/Award – Late 2020
  • Construction – 2021
Frequently Asked Questions (FAQ’s)

What are surveyors doing in my area?

Surveyors will be in the neighborhood to begin work by collecting various points of interest (e.g. meter boxes, elevations, existing site improvements, etc.). This includes locating and identifying trees by tagging them with a unique ID tag.

Can I remove tree tags?

No please don’t; these will be critical through the design phase to accurately map the trees on the plans and identify them in the field during construction.

Will new fire hydrants be added?

Currently, hydrants are spaced more than 1,000 feet apart in this area. PCWA standards call for hydrants to be spaced at a maximum of 500 feet for residential areas, 350 feet for commercial and industrial areas. This will require the construction of new hydrants.

For questions regarding this project, contact:

PCWA Associate Engineer
Jordan Jakobsen
Phone: (530) 823-4950

Map Figure of Alta Loop Pipeline Project
Map Figure of Alta Loop Pipeline Project (click to enlarge)

Lake Alta Dam Improvements Project

About Project

The Lake Alta Dam project is a multi-year project to address regulation changes since the two Lake Alta dams were installed. Originally constructed for mining activities in the 1850’s, the dams have been in continuous service ever since. This facility is an important component of PCWA’s water delivery system, and this project will ensure lake levels, vegetation, and drainage comply with current regulatory requirements. See below for document links for this project.

Project Location

The Lake Alta Dam Safety Project is located in the Town of Alta, near Bonny Nook Drive.

Construction Timeline

Consultants are currently gathering information on-site to be used to design improvements to the dams. Completion of design of improvements to the dams is anticipated in 2020. Any future construction work will proceed upon completion of design and regulatory approvals.

Latest Update

PCWA removed dead and dying trees in 2017 the vicinity of the dams to comply with direction from the California Division of Safety of Dams (DSOD). In winter of 2018/2019 PCWA collected bore samples from each of the dams. These samples were analyzed and will be incorporated into design of the necessary improvements.

For questions regarding this project, contact:

Project Manager / Engineer
Kelly Shively
Phone: (530) 863-8384

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