Levees and Floodplain Protection

We help our clients through the regulatory process associated with levee improvements and maintenance to insure the highest level of floodplain resource protection while meeting flood control mandates.

Levees provide critical flood control protection of urban and agricultural areas. In the aftermath of Hurricane Katrina in 2005, a 2006 evaluation of California’s levee system resulted in a declaration of a State of Emergency, leading to a broad program of evaluation and repair of the State and federal project levees. Yet a number of threatened and endangered fish and wildlife species that make use of these habitats may be affected by ongoing levee maintenance and repair.

Stillwater’s physical scientists, biologists, and regulatory experts provide an integrated suite of assessment, planning, environmental compliance, and mitigation services that streamline the regulatory process for levee maintenance, improvement, and setback projects to ensure the highest level of floodplain resource protection while meeting flood control mandates. Our in-depth knowledge of floodplain ecology, fluvial geomorphology, cutting edge analytical tools, and environmental regulations from across the west coast allow us to quickly respond to broad range levee- and riverbank-specific project assessment needs, as well as longer term planning, and regulatory compliance support services:

  • Geomorphic and hydrologic assessment, including sediment transport modeling
  • Comprehensive streambank surveys of erosion sites, shaded riverine aquatic (SRA) habitat, and vegetation mapping.
  • Special-status species surveys
  • Endangered Species Act Section 7 & 10 consultation and preparation of Biological Assessments
  • Preparation and filing of Environmental Permitting documents, pursuant to NEPA and CEQA, including cumulative, climate change, and growth-inducing impact assessment
  • Development of on-site and off-site habitat mitigation measures and habitat enhancement designs
  • Development of practical and effective avoidance, minimization, and mitigation measures using the Standardized Assessment Methodology (SAM), a computational modeling and tracking tool developed by Stillwater Sciences for the U.S. Army Corps of Engineers
  • Environmental compliance coordination, including mitigation monitoring and reporting plans, and construction-related compliance, such as pre-construction surveys, construction crew environmental awareness training, and environmental monitoring during construction.
  • Clean Water Act Section 401 certification and Section 404 permitting
  • Federal levee modification permitting, including Section 408 approval packages and Section 104 federal credit memos
  • Jurisdictional waters/wetland delineation and wetland mitigation design and monitoring
  • Lake and Streambed Alteration Agreements (Fish and Game Code Section 1601 and 1603)

The ability to provide integrated and consistent environmental and regulatory insight into the planning, environmental compliance, and implementation stages of levee projects conserves effort, improves working relationships with regulatory agencies, and saves money. These benefits are further realized in our mitigation measures and designs, which are based on scientifically-defensible data and proven methodologies.

We can provide Environmental Planning and Permitting assistance to Federal agencies through our GSA contract.