Reintroduction of Beaver Populations within the Jacoby Creek

Restoration of extinct beaver habitats will help to accomplish stream, wetland, and floodplain restoration. By constructing dams that impound water and retain sediment, beaver substantially alter the physical, chemical, and biological characteristics of the surrounding river ecosystem, providing benefits to plants, fish, and wildlife. The possible results are many, inclusive of: higher water tables; reconnected and expanded floodplains; more hyporheic exchange; higher summer base flows; expanded wetlands; improved water quality; greater habitat complexity; more diversity and richness in the populations of plants, birds, fish, amphibians, reptiles, and mammals; and overall increased complexity of the riverine ecosystems. (Beaver Restoration Guidebook). Beaver populations (preferably the original species) will be reintroduced into the Ancient Redwood Forest Ecosystem to help restore Old-Growth Watershed Conditions that used to exist within these ecological habitats. Beaver Populations are essential in the proper management of Tree Stands for the reproduction of the Old-Growth Redwood Forest Ecosystems and were vital contributors to the establishment of the original Old-Growth Forest Ecosystems. Research will be implemented for identifying the closest living releative(s) of the Humboldt Beaver Specie(s) that existed within this region prior to the 1800s. Closest living relatives will be brought into the Jacoby Creek for implementing reintroduction of Humboldt Beaver Populations to restore old-growth habitat conditions. It is unrealistic for any genuine watershed restoration work to be done without restoration of the beaver populations and their watershed habitat conditioning methods. The Wild Beavers will be brought in to freely preform their natural tasks, with the protection of human support. Beavers will be managed from disturbing already existing human establishments that would be adversely impacted from floodplains being reflooded. Beaver, Watershed, and ecological experts will be brought into research Wild Beaver Forest-Watershed Management Practices to incorporate into Forest Management Plans for the restoration and preservation of Old-Growth Ecosystems.  

Beavers prefer to build dams on small-medium size, low gradient streams (<6% slope). Original Stream Habitat Restoration Work will be focused on establishing basic foundational structure within the Ahmed Estate’s section of the Jacoby Creek to help reduce the gradient of the stream to preferable low-gradient levels for beaver habitation. Beavers make use of streams with: 

1. Vegetation for food 
2. Potential construction material to build dams and logs 
3. Preferred Food Species of genera Populus and Salix 

The introduction of Native Willow Trees for Live Crib Walls and Willow Tree Revetment to provide permanent natural dam-structures within the Jacoby Creek will establish preferred food sources, of willow trees, for beaver populations. The Willow Trees operating right along the creek, and within the creek, will provide long-term food sustenance that is easily accessible to reintroduced beaver populations. 

Beaver dams impound water in ponds and pools, and these impoundments slow the flow of the stream; this holds the water within the stream reach for longer periods and can increase base flows (reviewed in Pollock et al. 2003).  Some perennial streams transform into intermittent and/or ephemeral streams following the removal of beaver dams (Finley 1937, Wilen et al. 1975). The Upper Jacoby Creek Watershed has been transformed into intermittent streams following the removal of beaver dams from the creek. Water levels become too rapid during the rain seasons, are unable to retain high water levels shortly after, and become dangerously low during the dry seasons. Reintroduction of beaver populations have transformed some intermittent streams back to perennial streams (Dalke 1947, Pollock et al. 2003). Beaver created wetlands, slows water velocities, lateral spreading, and larger areas of soil saturation contributing to increases in both the surface and subsurface water present in a watershed (Naiman et al. 1986, Syphard and Garcia 2001, Pollock et al. 2003, Cunningham et al. 2006, Westbrook et al. 2006, Hood and Bayley 2008).  Surface water retention within watersheds are especially important for many aquatic species during low-flow periods. Typically, the amount of surface water present increases with the number of beaver dams on a stream reach (Johnston and Naiman 1990ab). The ponds and pools formed from beaver dams provide important slow-water habitat for birds, waterfowl, fish, aquatic invertebrates, mammals, and amphibians. Increasing the amount of ponds typically provide important habitat for both terrestrial and aquatic plants and animals. Beaver recolonization of the Jacoby Creek Watershed will increase base-flows, increase, and elevate the water table, reduce peak flows, and spread flows out over longer time periods.  Reducing peak stream flows provides water quality benefits in terms of sediment reduction and also retention of water within the watershed as surface or groundwater. By slowing the stream flow, beaver impoundments reduce erosive energy and increase retention time. During floods, energy is dissipated as the water flows through multiple small channels on the downstream side of the beaver dam (Pollock et al. 2003). Floodplain vegetation alongside and below the dam further dissipates energy as the water works its way back to the stream channel (Li and Shen 1973, Woo and Waddington 1990, Dunaway et al. 1994, Pollock et al. 2003). Beavers have the ability to improve the water quality of streams by reducing suspended sediments in the water column, moderating stream temperatures, improving nutrient cycling, and removing and storing contaminants. As ponds and pools fill and become deeper, the impoundments force flow laterally, causing overbank flow onto floodplains and creation of side channels, as water flows around beaver dams (Westbrook et al. 2006). These side channels and distributaries provide benefits such as alternative aquatic passage, dissipation of stream energy, hydrologic reconnection to the floodplain, and increases in the soil saturation area. All of these attributes help to create an intricate network of multi-threaded channels and wetlands. Beaver dams can also play a critical role in replenishing alluvial aquifers by trapping and storing water, redirecting surface water onto adjacent floodplains, and forcing water into the streambed and banks. Overbank flooding is generally thought to be the main hydrologic mechanism for replenishing groundwater in riparian areas (Workman and Serrano 1999, Girard et al. 2003, Westbrook et al. 2006). By attenuating the rate of water table drawdown during summer low-flow months, beaver dams can provide a constant supply of water to the riparian area, via surface and subsurface flow paths (Westbrook et al. 2006). This influence on the hydrological processes affects the development of the floodplain and riparian areas by maintaining high local water tables and deeper groundwater levels. Thus, beaver influence floodplain structure and function (Westbrook et al. 2006). 

Climate change is expected to increase drought and reduce snowpack. Water storage from beaver impoundments may be an effective tool to help mitigate the associated reductions in water resources (Rosemond and Anderson 2003, Lawler 2009). Climate change is of particular concern in areas that currently depend on glacial and snow-melt runoff. As water storage in the form of glaciers and snow decreases, surface and groundwater storage behind beaver dams high in watersheds may provide a buffer for base flows (Beechie et al. 2013). Hood and Bayley (2008) studied how temperature, precipitation, and beaver activity influenced the area of open water in east-central Alberta, Canada, over a 54-year span that included many periods of drought. The presence of beaver had a substantial effect on the amount of open water in wetlands within the study area. Hood and Bayley’s results indicate that beaver played a larger role in maintaining open-water areas than did temperature, precipitation, and climate. The authors found that, as sites cycled through beaver occupation and abandonment, beavers caused a nine-fold increase in open-water area compared to the same sites without beaver. Their findings indicate that “beaver could mitigate some of the adverse effects of climate change due to their ability to create and maintain areas of open water.” Hood and Bayley conclude by suggesting that “the removal of beaver from aquatic systems should be recognized as a wetland disturbance equivalent to in-filling, groundwater withdrawal, and other commonly cited wetland disturbances.” In addition to mitigating climate change-related decreases in stream flow, via surface water storage, beaver increase the amount of groundwater storage and aquifer recharge (Pollock et al. 2003, Westbrook et al. 2006). This ultimately may be the most important beaver-related factor in mitigating effects from climate change because groundwater is released more gradually than surface water and has no evaporative losses (BRM). In areas where groundwater is being depleted faster than it is being recharged naturally, beaver ponds may help to offset the aquifer depletion, especially when beaver activity is occurring at the reach or watershed scale. Furthermore, increased groundwater storage may help to offset rising stream temperatures associated with the increase in open-water surface area. Cold pockets of water have been found downstream of beaver dams, possibly from the upwelling of groundwater and an increase in hyporheic exchange (Pollock et al. 2007). This is particularly important for aquatic species that require cold water. Land use changes and ecosystem degradation already have caused summer water temperatures in streams and rivers to frequently exceed levels suitable for aquatic life (Kaushal et al. 2010). Climate change models predict that in the near future, water temperatures will increase even further. Maximum summer temperatures are often the single most important factor limiting the distribution and presence of numerous fish species in rivers (McRae and Edwards 1994, Wenger et al. 2011). Many salmon habitat restoration efforts in rivers and streams focus on increasing shade by bolstering riparian areas to reduce summer peak temperatures. In many regions, beaver dams have the ability to lower stream temperatures through the creation of riparian and wetland habitat. Vegetation associated with these areas offers shade that helps to lower stream and pond temperatures. Chesney et al. (2010) found that two beaver dams in the Shasta River in Northern California stabilized temperatures relative to upstream and downstream reaches that lacked beaver dams. Small beaver ponds may not have major temperature effects (Hoffman and Recht 2013). 

During floods, energy is dissipated as the water flows through multiple small channels on the downstream side of the beaver dam (Pollock et al. 2003). Floodplain vegetation alongside and below the dam further dissipates energy as the water works its way back to the stream channel (Li and Shen 1973, Woo and Waddington 1990, Dunaway et al. 1994, Pollock et al. 2003).  

Beaver habitats amplify watershed habitation for a broad range of diverse species. Beaver habitats promote vegetation, establish ideal conditions for increasing biodiversity among insect populations, enhance fish populations health and productivity, provides breeding habitat for amphibians, contributes important habitats for reptiles (turtles, snakes, lizards...), and offers refuge and protection for waterfowl and other bird populations. The reintroduction of Beaver Watershed and Wetland Managers will establish the conditions for the rehabilitation of Old-Growth Watershed Habitats across the Northern Region and Central Valley of California.