Maintenance and Watershed Management Programs


FLOOD CONTROL AND WATER CONSERVATION DISTRICTWatershed Management and Stream Maintenance

Napa Bridge

Stream Maintenance and Watershed Management Program

District's Stream & Watershed Maintenance Program Mission


The Napa County Flood Control and Water Conservation District (District) was formed in 1951 with the dual goals of providing flood protection and water conservation to NapaCounty. Over the years since the District’s forming, flood protection and water conservation approaches have evolved, particularly with regard to an increased focus on the protection of natural resources within the District’s boundaries. Local streams provide habitat for a range of flora and fauna including certain rare, threatened or endangered species. The District’s Stream and Watershed Maintenance Program enables the District at its discretion to attempt to reduce the potential for flood damage and enhance habitat along the riparian corridors on private and public lands throughout Napa County. The District responds to citizen and government alerts to potential flooding or erosion issues and works with property owners to enhance stream physical and biological processes. Maintenance is performed on an adaptive management approach and is prescriptive rather than routine in nature. The goal is to have a collaborative approach among local stakeholders to preserve Napa County’s riparian and stream resources while protecting life and property from flood damage. Milliken Creek
Link to map of Watershed Maintenance Program Area


Stream Maintenance Manual

The District has developed the Napa County Stream Maintenance Manual (SMM) to improve the management of streams and drainage channels in the District’s county-wide jurisdiction through establishing consistent guidance for stream maintenance activities. The SMM provides the organizational framework to oversee routine stream maintenance activities, including vegetation management, erosion protection and bank stabilization, sediment removal and habitat enhancement. The District’s stream maintenance approach relies on recognizing fundamental hydrologic, geomorphic and biologic processes that affect a given stream reach and adaptively manages and maintains streams based on the underlying processes. These maintenance activities occur mainly in engineered channels and “collectors”, modified channels and also in natural streams throughout Napa County on an as-needed basis.

 Updated Napa County Stream Maintenance Manual
 Napa County Stream Maintenance Program Initial Study/Negative Declaration



Dry Creek restoration before            Dry Creek restoration after

Before: Large downed tree crossing
Dry Creek and causing debris jam.


After: Large wood and rootwad preserved,
bank replanted and willow mattresses
installed along bank.


Stream Maintenance Program Annual Report

The District performs annual stream reconnaissance and assessments to identify potential maintenance needs in District-maintained channels and in tributaries prone to flooding. The District develops an annual work plan and coordinates with the appropriate regulatory agencies to implement stream maintenance projects as needed. At the end of each maintenance season the District produces an Annual Report which provides project summaries, project maps and locations, pre- and post-photo documentation and summaries of habitat enhancement efforts.

Stream Maintenance Program Annual Report

Stream Survey Postcard


Downed tree before


Downed tree after

Before: Large downed tree constricting flow
along the Napa River.


After: Tree limbs crossing channel removed and
large wood preserved to enhance
instream habitat.


Stream & Watershed Stewardship

The District sees stream maintenance as an integrated stream management approach that involves protecting and enhancing existing instream resources while providing for necessary flood conveyance capacity in the channel. The District has integrated habitat enhancement efforts into the Stream Maintenance Program to protect and enhance instream physical processes, water quality conditions, riparian vegetation and instream habitat. The District partners with local groups and other government entities to implement stream enhancement projects including invasive species management, native riparian planting projects, barrier and debris removal, large woody debris preservation and supports watershed and flood control studies. The District also offers a Stream Bank Stabilization Cost-Share Program to assist property owners with stream bank erosion issues.  The District's long-term vision is to create a diverse, mature and structurally complex riparian corridor that provides shade to the active channel, foraging and nesting habitat for many small mammals and birds, forage for aquatic species, moderates water temperatures and shades out invasive species. The District sees itself not merely as a flood management bureau, but more broadly as a resource management agency with a duty to integrate environmental benefits (such as habitat protection and enhancement) into stream maintenance activities.

Stream Bank Stabilization Cost-Share Program

Stream Maintenance Flyer

Non-native Invasive Plant Management

The District’s long-term habitat restoration goals include enhancement of the Napa River and its major tributaries, and the creation and restoration of brackish emergent marsh (tidal), seasonal and emergent freshwater wetlands, tidal mudflats, riparian and native woodlands. The broader goal is to establish an ecologically self-sustaining mosaic of habitats. The District’s stream management goals include ensuring that adequate flood conveyance capacity is provided, maintaining stable stream bank conditions, and enhancing instream ecological conditions. The District’s vegetation management and invasive species plant management efforts support countrywide restoration goals by:

1. Preserving and restoring upland, wetland, tidal, and woodland habitats throughout the County by identifying, mapping, and eradicating invasive plant species;

2. Avoid disturbing native habitat and plants areas and enhancing those areas through planting of appropriate native species.

Aquatic Pesticide Application Plan
State Water Resource Control Board: Statewide Aquatic Weed Control Permit
2017 Public Notice - Stream Maintenance Program - Invasive Management and Treatment Project Details

Arundo Removal Photo