What's New

Salmonid Rearing Habitat Delineation and Restoration Prioritization:  
East Austin, Pena, Mill, and Redwood Creek Watersheds

This project, designed to identify and prioritize stream reaches for habitat enhancement projects within four tributaries of the Russian River--East Austin, Mill, Pena, and Redwood Creeks--was completed in 2018.  The two-year project was conceived and executed by O'Connor Environmental, Inc. with assistance from its partner and fiscal sponsor, the Pepperwood Foundation. Funding was provided by the Fisheries Restoration Grant Program administered by the California Department of Fish and Wildlife.  The project team developed a unique approach combining the use of high-resolution LiDAR topographic data to support hydrologic and hydraulic modeling of fish habitat suitability with existing habitat and monitoring data to efficiently evaluate more than 80 river miles of streams.  The LiDAR data was obtained and made publicly-available by the Sonoma County Agricultural Preservation and Open Space District. Habitat and monitoring data along with technical input was provided by SeaGrant California and NOAA Fisheries.

Work products include a series of detailed prioritization maps for each of the study watersheds which identify and prioritize reaches and sites for habitat enhancement projects.

For more information please refer to the links below:






Weighted useable area classifications in the Mill Creek watershed
OEI Completes Comprehensive Study of Flow Availability Based Habitat Conditions to Assist Coho Restoration Efforts in Russian River Tributary Watersheds

The Dutch Bill and Green Valley/Atascadero Creek watersheds provide some of the best remaining habitat for endangered coho salmon in the Russian River Watershed.  State and Federal fisheries agencies have identified low stream flows during the summer months as a key limiting factor affecting the survival and recovery of the species.  O'Connor Environmental and the Gold Ridge Resource Conservation District with funding from the California Department of Fish and Wildlife's Fisheries Grant Restoration Program have completed a four-year scientific study to gain a better understanding of how stream flows vary across the watersheds and over time, how various natural and man-made factors influence these flows, and what actions can be taken to improve flows and habitat conditions for coho.  A major component of the project was the development of a distributed hydrologic model capable of representing both surface water and groundwater processes and the interactions between them.  This study provides a wealth of information and tools for understanding watershed conditions and assisting local stakeholders in sustainably managing water resources and restoring coho populations.


For more information please refer to the links below:






Mean annual groundwater recharge
Minimum water depths and extent of reaches where flows between adjacent pools habitats become disconnected
Change in groundwater elevations between October 2009 and October 2014
Flow availability based reach classification and restoration prioritization recommendations map
Implementation of California's Sustainable Groundwater Management Act (SGMA) in Underway

The Sustainable Groundwater Management Act (SGMA) was passed by the California legislature in 2014. The SGMA calls for local agencies to form Groundwater Sustainability Agencies (GSAs) by 2017 and develop Groundwater Sustainability Plans (GSPs) by 2020 for groundwater basins designated by the Department of Water Resources (DWR) as medium and high priority.  A key component of the GSPs will be defining sustainable management criteria and groundwater pumping thresholds designed to achieve these criteria.  In many groundwater basins sustainable management criteria will include the effects of groundwater pumping on stream flows and associated habitat conditions for threathened and endangered species.


Developing successful GSPs requires that we re-think traditional approaches that have tended to compartmentalize the hydrologic cycle and which are in conflict with scientific consensus that surface water and groundwater resources are inextricably linked.  OEI has a long history of conducting scientific investigations to evaluate the interconnection between surface water and groundwater.  Our staff are experts in the application of state-of-the-art computer models capable of simulating surface water/groundwater interactions and the effects of water use on aquatic habitat conditions.   As groundwater regulation in California proceeds, we fully expect that these models and methods will play an increasingly important role in the regulatory process and the development of GSPs throughout the state. Our expertise in evaluating surface water, groundwater, and habitat conditions make us uniquely qualified to assist GSAs, water users, restoration practitioners, and legal teams in navigating this evolving regulatory framework over the coming years.


For more information about the SGMA and our integrated modeling approach please refer to the links below:






New State and County-level Regulations for Cannabis Cultivation

As of February 2016, all cannabis cultivators with more than 2,000 square feet of cultivation area are required to enroll in a new state-wide water quality regulatory program being implemented by the North Coast Regional Water Quality Control Board.  Requirements depend on the size of the cultivation area and various site characteristics and may include the need to develop a Water Resource Protection Plan and/or a Cleanup and Restoration Plan.  In addition to the new state-level regulations, both Humboldt County and Sonoma County have recently enacted Cannabis Land Use ordinances, each with various permitting requirements.  With passage of Proposition 64, new regulations and associated permitting and reporting requirements will continue to develop throughout the state.


OEI staff have the expertise to assist growers in navigating this evolving regulatory framework including assistance with evaluating water supplies and obtaining Water Rights, developing stormwater drainage and erosion control measures and plans for roads and cultivation areas, and cleanup and restoration of existing non-compliant site features.   

For more information please refer to the links below: