By Audrey Zitnay:
On Friday, October 6th our Restoration Ecology class had the opportunity to travel to the Lagunitas Creek arranged by our professor Wendy St. John. Lagunitas Creek is a 20 mile creek located in Marin County that flows through Mt. Tamalpais area and eventually enters the Pacific Ocean at Tomales Bay. The National Park Service, Open Space districts and municipal agencies oversee the 110 square-mile watershed. Half of it is actually private ownership with residential and agricultural use. The creek serves as an important system function due to the fact that is provides most of the main water supply for almost all of Marin County and as well habitat for endangered Coho Salmon, threatened Chinook Salmon and Steelhead, and rare shrimp species.
As stated above, that residential/agricultural usage is a large part of the land, however this had significant impact on the creek because of wanting to expand farm land, which led to the morphology of the creek to change. This led to the installation of man-made dams which helps to moderate the momentum of the water flow.
Moderating the water velocity is crucial because when large/abnormal amounts of water comes along (usually from heavy rainfall) the creek becomes a dangerous high velocity stream without anything to slow it down such as heavy, large rocks, logs or down trees. This ultimately effects salmon populations because the young salmon who live/thrive in the stream get swept to the river because of the rapid pace of the water and die. They have no chance at survival. Not only do the dams help protect and ensure species survival but they assist with the prevention of sediment build up that occurs at the bottom of the river to make sure it is dispersed evenly. Along with viewing the dam addition, we got to visit the restoration site that was put into place to increase biodiversity within the Lagunitas creek. In order to achieve this, logs were placed within the stream to provide areas where the water did not run as fast and serve as a break in order for aquatic organisms to have an area to hide from predators, rest, lay eggs or thrive. This assists with the prevention of many salmon deaths. Overtime this logs would eventually become lose during possible storms, animals or human activity. Due to this case, the logs were anchored down. During this process it was crucial to the restoration team that no species where disturbed or habitat ruined and therefore were very careful of their actions.
We got the chance to explore a cite out of 8 total where new channels were made in hopes to increase the amount of flood plains on used farm fields. Here native vegetation was planted, mostly willows. The process of these site restorations took a while, which was mostly due to the permits that had to be obtained and paperwork that had to be completed. As well a certain species of bird nests were found in one of the trees that was either threatened or endangered and therefore they had to wait until the nesting season was through to begin the restoration work. In total the cost was around $40,000.
The restoration team that works for the Lagunitas Creek have a common goal in mind – saving the Coho Salmon and Steelhead trout – while restoring the creek to be a viable habitat for the time to come.
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