Habitat Enhancement Projects
The Mattole River is subject to high sediment loads, warm water temperatures, low flows and minimal protective cover for fish. MSG implements instream habitat enhancement projects to improve salmonid habitat and restore watershed functions.
Estuary Bar APex Jams
The bar apex jam structures in the estuary are the largest structures the MSG has completed to date. Currently, the Mattole River estuary offers poor habitat for salmon due to a number of factors. Historical logging in the watershed, seismic activity, and major flooding events between 1950 and 1970 have filled the estuary with sediment. Temperatures of the water in the shallow estuary often climb to lethal levels for salmonids during the summer months. In order to address the higher temperatures, the MSG has incorporated apex jam wood structures into the sand bars of the estuary. The jams, which consist of dozens of logs anchored to boulders, work with the rivers hydrology during high flows to create deep pools. The shade from the wood combined with the deeper pools help reduce the temperature of the water and provide fish with an area to rest and hide.
Location of constructed bar jams, more structures are planned for construction this year
Large Wood Structures
Similar to the concept of apex jams, large wood structures are log jams placed within streams to scour out deep habitat pools. These structures are placed primarily in the Mattole River headwaters and are intended to create habitat for both spawning adult salmon and juveniles. Plans are being developed to add wood structures in the middle mainstem (Honeydew to Ettersburg).
MSG staff anchoring logs for a large wood structure
Ground water recharge
The ground water recharge project is a proposed extension of MSG's wood structure projects. Working in collaboration with Sanctuary Forest, the MSG will install wood structures specifically designed to hold back some water in a stream and replenish groundwater supplies. Structures will span the entire width of a stream, creating a holding pool of water while minimally interrupting the connectivity of the stream. The pools will not only allow water to seep into the ground but also provide more habitat for salmonids. The goal of ground water recharge is to improve the overall water retention of the Mattole River during the summer when water flow can become dangerously low.
Culverts often hinder fish passage to good upstream habitat. The MSG works to widen and improve culverts to allow unhindered fish migration.