Background
In Oregon, tide gates are commonly used to control water in tidally influenced areas along the coast and lower portions of the Columbia River Basin. Traditionally, tide gates are constructed by integrating one-way doors (i.e. the tide gate) into a dike. Freshwater drains from streams above the tide gate during outgoing tides. Water pressure from incoming tides closes the gate, protecting agriculture, infrastructure, and other developed landscapes from tidal inundations. Unfortunately, preventing inundation can also slow or prevent tidal flows into the estuaries, which can impede the migration of native fish, diminish water quality, and reduce estuarine ecological functions. OWEB grants have supported a variety of tide gate projects that enable fish passage to important habitat and protect coastal communities from tidally influenced flooding.
Did You Know?
- There are about 1,000 tide gates in estuaries along the Oregon Coast and along the lower Columbia River, many in need of repair.
- If tide gates fail, roads, businesses, homes, and agricultural lands become more vulnerable to flooding and intense winter storms.
- A well-designed and managed tide gate keeps farmlands productive, manages tidal flows to allow migration of native fish, and maintains water quality.
The Oregon Tide Gate Partnership
The Oregon Tide Gate Partnership is a coordinated effort of state and federal agencies, agriculture and conservation organizations, county leaders, and coastal landowners. Together, we are working to achieve more resilient coastal communities by protecting landscapes that support local economies and enhancing the ecological function of Oregon’s estuaries for fish and wildlife. the Tide Gate Partnership convened from 2017 – 2024 to understand the challenges related to tide gates in Oregon and work toward finding solutions around funding, engineering and design, and permitting.
The tide gate infrastructure in Oregon is aging. Much of it will benefit from repair, replacement, or removal in the coming years. The Tide Gate Partnership focuses on addressing the challenge of repairing this aging tide gate infrastructure to protect communities and providing assistance to tide gate owners in coastal Oregon.
Tools and Resources
The Tide Gate Inventory allows for a greater understanding of the issue of aging tide gate infrastructure on the Oregon coast, by identifying the number, location, upstream and downstream resources of existing tide gates. It provides a framework to consider risks, benefits, costs, and appropriate solutions. This inventory was compiled by The Nature Conservancy using data from field inventories performed by watershed counsels and other organizations. Basins were inventoried between the years 2015 and 2022.
View The Oregon Tide Gate Inventory
View The source data for the map
Decision support tools are created and used to guide outreach, inform planning, analyze and prioritize information, and facilitate decision-making. The Tide Gate Decision Support Tool provides a flexible and systematic approach for identifying priority tide gate project sites from a multitude of perspectives.
The tool can be used by funders, local governments, restoration partners, and others to evaluate project sites at a local, regional, or coast-wide scale for a variety of potential outcomes, including, for example, agricultural land protection, economic development benefits, community benefits, flood reduction, community resilience, infrastructure improvements, water quality, ecosystem function, and fish habitat.
To learn more about the Tide Gate Optimization Tool or access the tool for use, please contact Jason Nuckols at The Nature Conservancy,
jnuckols@tnc.org
More information about the Decision Support Tool
All engineering designs for tide gate repair or replacement projects must meet local, state, and federal regulatory requirements to construct the project. One of the biggest regulatory influences on tide gate designs is the state and federal fish passage requirements. Design options must meet requirements for fish passage, but the preparation of engineering plans can be challenging and costly. Resources to help reduce the cost of project engineering are needed.
A subgroup of Tide Gate Partnership members has worked with an engineering firm, Northwest Hydraulic Consultants (NHC) to develop an engineering tool. It is a model that is intended to serve as a simple tool for both landowners and technical support organizations, who possess the necessary construction knowledge and resources, to properly size and install a tide gate pipe that fulfills both state and federal fish passage regulations. The tool should also provide both a cost-benefit and time savings for landowners who do not have or cannot secure, the funding necessary for more complex hydraulic modeling.
An instructional video demonstrates how the Tide Gate Pipe Sizing Tool works.
Pipe-Sizing Tool
All tide gate repair or replacement projects must meet regulatory requirements and secure permits prior to beginning construction. The regulatory review and permitting process can be challenging and time-consuming. To navigate the process, the following resources are available.
Regulatory Process Maps
The Regulatory Process Maps outline the roles and responsibilities of the landowner, permitting agencies, and others, and include expected outcomes. The process maps are available in two versions:
Additional Resources
Pre-Project Information Form
In 2024, with a grant from OWEB, the Coquille Watershed Association (CoqWA), The Nature Conservancy (TNC), and Tillamook Estuaries Partnership (TEP) developed the Tide Gate and Tidal Wetland Monitoring Guidance and Protocols for Estuary Practitioners handbook with input from the Columbia River Estuary Study Taskforce, the Confederated Tribes of Siletz Indians, and Laura Brophy at the Institute for Applied Ecology. This project was inspired by Souder et al. (2018), who recognized the need for a standardized set of tide gate monitoring protocols. The tide gate community was surveyed and interviewed to determine what new resource could be created to guide practitioners through implementing a state-water standardized monitoring framework. This document reflects that input.