Gunnison Sage Grouse Habitat Restoration: An Introduction
Our Crew has started working on the Gunnison Sage Grouse Habitat Restoration Project. This is an intensive Project that involves many groups, organizations, and parties. We will introduce our project partners and funding agencies in later posts but would like to give you an introduction to the work we are doing now.
The Gunnison Sage Grouse is classified as a threatened species and is protected by the endangered species act. Part of the reason this species is threatened is due to the lack of wet meadow habitat that the bird uses to feed and provide for its young. In order to mitigate the loss of wet meadow habitat the WCCC is building specific rock structures that will provide erosion control.
Why is there a lack of wet meadow habitat you may ask? before people came to settle western Colorado natural wet meadows had formed in the valley bottoms among the rolling hills. The water flowed through the plants and foliage and dispersed evenly along the valley floor creating excellent habitat for many animals including the Gunnison Sage Grouse. These wet meadows were a place to forage and find food throughout the year. But with the introduction of settlers and domesticated grazing animals to the area everything changed. Wagon wheels and grazing cattle made there way up the gradual valley floors and created ruts and social trails that provided a path of least resistance for the water that formed the wet meadows. Over time the water changed its coarse and began to erode the soil where wagon wheels and cattle hooves had created a path. With over a hundred years gone by there are now pronounced gullies that have drastically altered the water table and habitat for wildlife in the area. The wet meadows have diminished and with them the Gunnison Sage Grouse population. This is why we are working hard to provide erosion control for the greater Gunnison area where the Gunnison Sage Grouse lives.
We will be building 4 different structures; One Rock Dam, Rock Mulch Rundown, Zuni Bowl, and Media Luna. These structures are not just piles of rock, they serve a specific purpose and are intentionally designed. Working with Bill Zeedyk who wrote "Let The Water Do The Work: Induced Meandering, an Evolving Method for Restoring Incised Channels" we learned how to work with rock and implement the following structures.
One Rock Dam "ORD"
A low grade control structure built with a single layer of rock on the bed of the channel. ORDs stabilize the bed of the channel by slowing the flow of water, increasing roughness, recruiting vegetation, capturing sediment, and gradually raising the bed level over time. ORDs are also passive water harvesting structures. The single layer of rock is an effective rock mulch that increases soil moisture, infiltration, and plant growth. Original concept developed by Bill Zeedyk.
Rock Mulch Rundown
A headcut Control structure where the face of the headcut has been laid back to a stable angle of repose (minimum of a 3:1 slope), and then covered with a single layer of rock mulch. The mulch serves to slow runoff, increase soil moisture, recruit vegetation, and ultimately prevent the headcut from migrating further upslope. Rock Mulch Rundowns are ONLY to be used on low energy headcuts, like those found in upland rills and gullies with small catchment areas, and where sheetflow collects and enters a channel. Original concept by Craig Sponholtz.
an in-channel headcut control structure composed of rock-lined step falls and plunge pools that prevents headcuts form continuing to migrate upstream. Zuni Bowls stabilize actively eroding headcuts by dissipating the energy of falling water at the headcut pour-over and the bed of the channel. The structure converts the single cascade at an eroding headcut into a series of smaller step falls. Zuni Bowls also serve to maintain soil moisture on the face of the headcut, encouraging the establishment of protective vegetation. Original concept developed by the people of Zuni Pueblo and Bill Zeedyk.
there are two types of Media Luna structures - both used to manage sheet flow and prevent erosion. "Sheet flow collectors" (tips DOWN) prevent erosion (small headcuts) as the head of rills and gullies by creating a stable transition from sheet flow to channel flow at the collection point. "Sheet flow spreaders" (tips UP) are used to create a depositional area on relatively flat ground by dispersing erosive channelized flow and reestablishing sheet flow where it once occurred. Original concept developed by Van Clothier.
(Taken from the "Erosion Control Field Guide" by Craig Sponholtz & Avery C. Anderson Sponholtz)
These structures are built for two reasons. The first is to prevent any further erosion from happening. The second is to restore the habitat by collecting sediment and slow down water runoff and replenish water storage by allowing it to seep into the ground. The impacts that these structures will have on the environment will be long lasting and beneficial. We are honored to be able to help restore habitat for a federally protected species especially when we know that the work we do will make such a difference.
Please check back again soon for more posts about our Gunnsion Sage Grouse Habitat Restoration Project and to see updates about project progress and who we are working with.