Fluvial Geomorphology

Representative Fluvial Geomorphology Projects

O’Connor Environmental, Inc.

Geomorphology ▪ Hydrology ▪ Engineering Geology

P.O. Box 794, Healdsburg, CA 95448 (707) 431-2810

Text Box: OEI has participated in several stream restoration projects serving as project fluvial geomorphologist. We have played a key role in developing technical documents required for restoration project permitting from State, Federal and local entities in Mendocino , Sonoma and Napa Counties. We have also planned and implemented sediment cleanup in stream channels, and developed monitoring plans to document restoration effectiveness.

Lagunitas Creek Fine Sediment Study, Marin County, California

Performed a systematic survey of fine sediment in Lagunitas Creek for the Marin Municipal Water District. The survey included habitat classification, pebble counts, sampling of spawning gravel, and hydraulic modeling to determine the proportion of the channel bed composed of fine sediment and the impact of existing dams on fine sediment conditions. Statistical analysis of sediment samples provided confidence intervals for sediment size distributions. Link to PDF Report

Green Valley Creek Spawning Habitat Assessment

Lead consultant working with Sonoma County Water Agency, and Circuit Riders Productions, Inc. Conducted a habitat assessment for coho salmon on Green Valley Creek, a tributary to the Russian River. Assessment included an analysis of fluvial geomorphology, habitat conditions and spawning gravel quality. Statistical analysis of sediment samples provided confidence intervals for size distribution of spawning gravel. Link to PDF Report

Adaptive Geomorphic Plan for Willow Creek, Sonoma County, California

Surveyed and evaluated current fluvial geomorphic conditions of Willow Creek and its floodplain, as a response to historical stream and land management practices in the watershed. Evaluated future conditions regarding fish passage and habitat in regard to a proposed new bridge crossing the creek. Field investigations were supplemented by existing information and prior reports. An adaptive management and monitoring plan was recommended. Link to PDF Report

Pescadero/Butano Creek Watershed Assessment

Watershed-scale assessment of channel geomorphic conditions in Pescadero Creek (in association with ESA); reconnaissance surveys of fluvial geomorphologic conditions in sample reaches that complemented watershed scale investigations pertaining to erosion and fish habitat. The channel survey protocol was based on systematic quantitative and qualitative observations of channel conditions that identify fish habitat limitations along with sediment transport and routing systems at the watershed scale. Link to PDF Report

Russian River Bypass Channel Design and Bank Restoration Analysis

OEI developed a hydraulic design for construction of a temporary by-pass channel for the Russian River in association with Bioengineering Associates, Inc. Analysis of stream channel sediment size distributions, flow records, and determination of design constraints for stable channel geometry constituted the main effort for this project. In addition, OEI conducted HEC-RAS studies for the engineered design channel and prepared project descriptions and analyses necessary for County permitting and Clean Water Act Section 401 Certification.

Habitat Conservation Plan Watershed Analysis; Stream Channels, Sediment Routing and Flood Hazard Analyses

Lead fluvial geomorphologist in adaptation of Washington DNR Watershed Analyses for use on northern California forestlands. Stream Channel module coordinator for Freshwater Creek Watershed Analysis. Developed sediment budget from multiple sediment source studies and estimated transport rates and residence times using sediment transport calculations at representative reaches.

Geomorphic Analysis of In-Stream Aggregate Mining, Gualala River Annapolis, Sonoma County

Conducted an analysis of geomorphic response of stream channels following gravel mining operations in the Wheatfield and South Forks of the Gualala River as required for CEQA monitoring. Gravel recharge rates were estimated quantitatively from cross-section monitoring data and extraction rate data. These rates provided an evaluation of gravel extraction rates that can be maintained without causing channel bed degradation. This analysis also provided recommendations regarding future monitoring studies and methods for regulating gravel skimming operations.

Stream Sedimentation Rehabilitation and Monitoring Plan

Stream channel remedial work involving hydrological analysis, sediment deposit mapping and cleanup, spawning substrate characterization and applied fluvial geomorphology studies, Mendocino County. Worked on property owner’s behalf to resolve Cleanup and Abatement Order by NCRWQCB.

Monitoring Plan for Instream Gravel Mining Operation, Gualala River

Provided geomorphic analysis and relevant for a monitoring plan for instream gravel mining operations in the Gualala River, in accordance with County, State and Federal regulatory review. The monitoring plan was designed based primarily on topographic surveys of the mining areas to determine the impact of gravel mining on the geomorphology and salmonid habitat of the river.

Channel Migration Zone Assessment, Mendocino County, California

Analyzed times series aerial photography of 52 miles of major streams in Mendocino County, California, to determine extent and frequency of channel migration during the past 30 to 40 years. Assessed likely extent of future channel migration based on time series analysis and field observations of channel response to recent high flows since 1995.

Mark West Creek Stream Restoration

Technical advisor for development of restoration plans for a portion of Mark West Creek, Sonoma County, in cooperation with California Conservation Corps and Department of Fish and Game. Restoration work included boulder and large woody debris placement for bank protection and salmonid habitat enhancement.

Stream Restoration Plan Geomorphic Analysis, Selby Creek, St. Helena, Napa County

Conducted a fluvial geomorphic analysis and evaluation of proposed channel and bank restoration plan for a Napa Valley Tributary. Evaluated potential hydraulic change and effects on flood elevations resulting from specific restoration treatments. Study prepared for review by Napa County Resource Conservation District.

Channel and Bank Restoration Geomorphic Analysis, Ackerman Creek, Ukiah, Mendocino County

Conducted a preliminary fluvial geomorphic analysis of channel conditions and flooding related to channel aggradation, downstream bridges, grade controls and riparian vegetation. Evaluated US Fish and Wildlife Service analysis of conditions and recommended alternative conceptual restoration approaches.

Bank Restoration Conceptual Plan, Carneros Creek, Napa County

Geomorphic analysis of approximately 1 mile of stream channel focused on design criteria for stream bank restoration project. Sub-contractor to CDM.

Bank Restoration, Russian River, Alexander Valley, Sonoma County

Prepared topographic maps and hydraulic analysis for restoration of ~1000 ft of stream bank. Evaluated potential change in flood elevation for County permits; project team included Bioengineering Associates, Inc. and Green Valley Engineering.

Previous Stream Restoration Projects

Office Location: 447 Hudson St. Mailing Address: PO Box 794, Healdsburg, CA 95448 Ph (707) 431-2810 Fax (707) 473-9050

Text Box: OEI specializes in fluvial geomorphic analysis of stream channels from headwaters to large rivers at scales ranging from a project reach to the full watershed. Analysis and interpretation of geomorphic processes, and how these relate to fish habitat characteristics and sedimentation, is a particular area of expertise. OEI has developed monitoring plans for aquatic habitat and instream gravel mining operations, as well as surveying baseline conditions for trend monitoring. Detailed investigations of sediment transport, channel sedimentation, spawning gravel quality and large woody debris are typical project elements. Channel hydraulics are evaluated using a combination of field survey data and specialized software such as HEC-RAS and WinXSPro, depending on project

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