Beaver dams are flooding trails in Liberty Lake County Park. Officials are asking users to put up with the inconvenience because the work is enabling what would be a million-dollar restoration project to take place naturally.
Beavers deserve thanks for wetland work
By BiJay Adams and John Bottelli
6/16/2010 10:11:00 AM
Liberty Lake Voices
Over the past 150 years, Liberty Lake and the wetland at the south end of the lake has had an extensive history of human intervention, not unlike many wetland areas in the United States. Ranching, farming, stream diversion, dewatering and channel diking have all had an effect on the lake and associated wetlands. These disturbances have negatively impacted water quality through the elimination of a functioning wetland and the loss of connectivity to its only source of water, Liberty Creek. Prior to these disturbances, beavers were known to have inhabited the area and the creek likely entered the lake naturally through a series of braided channels and wetland complexes. This pre-settlement wetland area would have provided beneficial wildlife habitat, ground-water recharge and storage, and water quality functions such as reduction of flow, flooding, and trapping of nutrient-rich sediment.
Despite being undisturbed for several decades, the wetland at the south end of Liberty Lake continues to be degraded due to past human activities. However, the beaver activity observed over the past seven years at Liberty Lake County Park is helping to reverse that current degradation by facilitating wetland restoration through their ongoing activities for the benefit of the lake and the Spokane-Rathdrum Prairie Aquifer - for us, for free! In essence, the beavers are saving us the cost of an expensive wetland restoration project that has been estimated at nearly a million dollars.
Beaver have been key agents of riparian succession and ecology throughout North America. The beaver is considered a "keystone species" (think prairie dogs, grizzly bear, sea otters) because it fundamentally influences the ecology of an area and helps to maintain biodiversity and the local food web. The proven benefits of beaver have demonstrated: 1) an elevated ground water table upstream of the dam, which improves vegetation condition, reduces water velocities, reduces stream bank erosion, reactivates floodplains, and improves fish habitat; 2) a reduction in sedimentation downstream of the dam; 3) increased water storage and groundwater recharge (more cold water springs recharging streams, lakes and aquifers); 4) improved water quality; and 5) acceleration in the natural restoration of degraded or lost riparian systems.
Even with these undisputed benefits, beaver have yet to understand the nuances and importance of public relations. All joking aside, the engineering works of beavers often conflict with home owners, recreationists, utilities, roads and other human enterprises. Complaints about blocked culverts, flooding, inundation and tree damage have sharply increased as beaver populations have expanded into territory they were extirpated from more than a century ago.
Liberty Lake County Park is no exception. The beavers that moved in seven years ago have altered the landscape dramatically and have affected the way people can use the park. Spokane County Parks Department has been working with local experts and residents to mitigate the negative effects of the beaver while also allowing the free wetland restoration work to continue. For example, in 2004 when beavers were being poached and their dam complexes were being removed by angry park users, the Spokane County Parks Department constructed a new trail on the west side of Liberty Creek to avoid future conflicts with beavers and trail users.
Today, the main trail system and the connection to the Edith Hansen trail is being flooded by beaver dam activity. Knowing the popularity of this trail and the need to balance restoration activity with the recreational needs of the public, Spokane County Parks has teamed with the Washington Trails Association and the Backcountry Horsemen to reroute a section of trail, thereby preserving hikers' dry feet while allowing the beaver room to continue their wetland restoration work.
So, the next time you visit the Liberty Lake County Park, be sure to stop by and thank the beaver for all their beneficial hard work on our natural wetland restoration.
For More ...
To learn more about beaver or the new trail construction, contact either:
• BiJay Adams, water resource and lake protection manager with the Liberty Lake Sewer and Water District, 922-5443
• John Bottelli, assistant director of the Spokane County Parks Department, 477-2529.