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| Griff Creek Stream Environment Zone Watershed Restoration Project |
Placer County, California |
Primary Project Type: Instream Restoration
Secondary Type: Fish Passage |
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Prior to restoration, the area downstream of the municipal water supply reservoi... |
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Primary Problem: Sedimentation
Secondary Problem: Dams |
| Main Restoration Action(s): Channel reconstruction, Dam removal |
| Native Fish Focus: N/A |
Is this project part of a watershed scale restoration? No
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| Project Dates: 1991 to 1996 |
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Initial Monitoring: 1991
Restoration Implementation: 1994
Follow-up Monitoring: 1995-1996 |
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Lead Agency:
North Tahoe Public Utility District, Tahoe Vista, California
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| Project Partners: |
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| Project Location:
The project was located in Kings Beach, California, an unincorporated area of Placer County within the Lake Tahoe Basin. Griff Creek is a tributary of Lake Tahoe located on the lake’s northern shore.
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Project Description:
For many years the North Tahoe Public Utility District maintained a municipal water supply reservoir on Griff Creek and, as a result, water supply features were constructed to facilitate water delivery to the community of Kings Beach. The most prominent feature was a concrete-faced earthen dam across Griff Creek constructed during the 1930s. Over the years, the dam fell into disrepair; reinforcements in the concrete face were neither stable nor aesthetically pleasing. In addition, scour below the structure was creating downstream sediment problems and fish and wildlife habitat was being degraded. During high flow events, Griff Creek contributed a lot of sediment to Lake Tahoe. In 1991 the District embarked on the Griff Creek Stream Environment Zone and Watershed Restoration Project to remove the dam, fill in a section of eroding diversion ditch, close and revegetate a dirt road leading to the site, improve fish habitat, and restore the drainage to pre-dam conditions.
Inter-Fluve, Inc. of Hood River, Oregon was retained by the North Tahoe Public Utility District to develop designs for the restoration of a defunct municipal water supply reservoir, a sediment settling basin, and a stream diversion ditch. Inter-Fluve formed a design team with Western Botanical Services of Reno, Nevada and Haen Engineering of South Lake Tahoe, California. During the preliminary design process a technical advisory committee was formed and information was gathered on basin hydrology, geomorphology, and fish and wildlife habitat. Three restoration alternatives were developed. These alternatives were conceived with the assistance of the advisory committee, which consisted of representatives from the Tahoe Regional Planning Agency, the US Forest Service, California Department of Fish and Game, Lahontan Region of the State Water Quality Board, the California Tahoe Conservancy, a local home owners association, and the North Tahoe Public Utility District. |
Project Goals: The primary design objective was to eliminate erosion hazards. This required the following: 1) removal of the reservoir dam, which presented long-term erosion hazards; 2) transfer of stream flow from the existing diversion ditch to the historic Griff Creek channel (which was considerably more stable than the ditch); 3) stabilization of banks and sediment in the diversion ditch; 4) control of runoff flow in the diversion ditch; 5) treatment of the stilling basin to prevent berm failure; and 6) re-vegetation of disturbed and eroding areas to provide long-term erosion control.
Secondary design objectives included: 1) restoration of natural land forms and functions; 2) improvement of aesthetic qualities; 3) reduction or elimination of public safety hazards and; 4) improvement of fish and wildlife habitat. An important feature of all design objectives was to restore the area by constructing features to function much like natural features in undisturbed environments. |
| Project Methods:
The restoration project, constructed during the fall of 1994, included the removal of the concrete-faced earthen dam across Griff Creek, the restoration of the stream through the dam footprint, and the restoration of a diversion ditch which bypassed the dam. Additional modifications within the watershed included installation of a series of jump pools for fish passage and the removal of a sediment settling basin. Innovative site de-watering and construction sequencing were used to minimize impacts to the area’s fish and wildlife and downstream habitat.
Click here for more information on Channel Reconstruction and Revegetation Techniques.
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This photo depicts the construction of the Griff Creek stream channel and instal... |
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Taken in July of 1995, this photograph depicts the status of restoration activit... |
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| Monitoring Data and Collection
Methods: Prior to restoration construction activities, surveys of the vegetation and topography were conducted to provide a basis for future monitoring of restoration efforts. Immediately after construction (autumn 1994), topographic and ocular surveys were conducted. Additional post-construction monitoring was completed in the summer of 1995 and 1996.
Click here for a description of monitoring methods.
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| Was this project effective
and how was this determined? Post-project monitoring documented re-vegetation of the site and success of stream bank stabilization efforts. Post-project photo monitoring also demonstrated earth forms were stable following two complete dry and wet seasons. The spring of 1995 saw a stream flow event near the 10-year recurrence interval. Despite the magnitude of this flood event, the stream channel showed little effects of erosion and the re-vegetation efforts were proceeding nicely.
Click here for more information.
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(Before) This photograph was taken during the channel reconstruction of Griff Cr... |
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(After) This photo was taken several years after restoration activities were imp... |
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| Confounding Effects/Additional
Information: |
| Project
Specs (all specs are estimates): |
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Cost of Materials:
Unknown. The cost of most materials was included in the bid amounts, which also included contractor’s labor, overhead, and profit to incorporate the materials into the finished work.
Subcontracted Costs:
$153,100 Design (including pre-construction monitoring), $214,800 Construction, $26,600 Post Construction Monitoring and Reporting
Overall Estimated Cost:
$430,500
Landowner Contribution:
Cash: In-kind: $36,000 in Permitting, Construction Management, and Administrative Services. |
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| For more information on this project
contact: |
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Mr. Leon (Lee) Schegg, North Tahoe Public Utility District, Tahoe Vista, California, Email: lschegg@ntpud.org
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| This information
was collected by: Michelle White |
| Project last updated on: 10/27/2006 |
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