Martin Slough Enhancement Project

The Martin Slough and Elk River estuary are part of the larger Humboldt Bay ecosystem that accommodates a variety of waterfowl, wading birds and shorebirds, several species of fish and other aquatic organisms, passerines, and raptors. Not much is known relative to the historic composition of the lower portions of Martin Slough. However, it is apparent from its elevation relative to tidewater and its geomorphic features that the lower portions of Martin Slough consisted of estuarine habitat, likely composed of some salt marsh and slough channels along with other more brackish water habitats. Although much of the historic estuary has been converted to other land use, some estuarine habitat still exists. That habitat has been severely degraded by the installation of tidegates at the confluence of Martin Slough with Swain Slough
and other land management practices. These modifications also have had a pronounced effect on flood routing and sedimentation in the lower channel.

Martin Slough has a watershed area of approximately 5.4 square miles, and natural channel length of over 10 miles with approximately 7.5 miles of potential salmonid fish habitat supporting coho salmon and cutthroat trout. However, the existing tidegates partially block upstream salmonid migration. The lower portion of the watershed flows through low gradient bottomland containing the golf course and pastureland. Many of the stream channels flow from gulches that contain mature second-growth redwood forests. The upper portions of the watershed are either in urban settings, or are recently harvested timber lands slated for future residential areas.
The Martin Slough Enhancement Feasibility Study area consists of the general flood plain
between Swain Slough and the upper (second) Fairway Drive stream crossing in the lower Martin Slough watershed. Existing problems that have been identified in the Martin Slough study area include limited fish access, poor fish habitat, large sediment loads, poor sediment routing, lack of riparian habitat, and frequent prolonged flooding that has a negative economic impact on current land use.

Several alternatives were evaluated in the Martin Slough Enhancement Feasibility Study (2006).  The preferred alternative consists of removing the existing tidegates, installing new tidegates with a habitat door designed to create a muted tide cycle and facilitate fish passage, increasing the size of existing ponds, creating new ponds, and making channel modifications throughout the project area.