Water Stewardship Information Sources
| Citation | Tuttle, K.N. 2012. Monitoring of the constructed wetland at Diversion Reservoir, Jordon River Watershed, Southern Vancouver Island. LGL Report EA3285. Unpublished report by LGL Limited environmental research associates, Sidney, B.C., for BC Hydro, Fish and Wildlife Compensation Program (Coastal), B.C. 42 pp. +Appendices. |
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| Organization | BC Hydro |
| URL | http://a100.gov.bc.ca/appsdata/acat/documents/r39977/11.W.JOR.01_wetland_2012_1384884617415_e7172081834e6bb8015466742d0160b0b99e168c020aae123257949f2c63377d.pdf |
| Abstract/Description or Keywords | Constructed wetlands are one example of habitat restoration that can be effectively used to mitigate for the loss of aquatic habitat and to offset the impacts of human activities such as hydroelectric development. The strategic water plan for coastal BC Hydro identified the loss of wetland habitat as having a major impact on wildlife in the Jordan River Watershed on southern Vancouver Island (BC Hydro 2001). In 2009, as part of a habitat restoration strategy developed for BCRP for the Jordan River Watershed, LGL Limited designed and built a two-tiered wetland on the edge of Diversion Reservoir to compensate for habitat that was lost during the impoundment of Jordan River in 1911. This constructed wetland monitoring project builds on amphibian species-at-risk surveys (2005) and work completed under grant 06.W.JOR.01: Jordan River Integrated Wildlife Habitat Restoration Plan and Constructed Wetland Design (2006). The wetland construction was a proof-of-concept build that if successful, can be applied to other watersheds that comprise the Bridge Coastal system. The implemented constructed wetland design included a lower pond of 3,300 m2 and an upper pond of ~4,050 m2 . The constructed wetland is situated entirely within the drawdown zone of Diversion Reservoir and earthen berms were constructed to retain water with an expectation that the berms would be overtopped by Diversion Reservoir at certain times of the year. Although the wetland was built (2009) and initial re-vegetation was completed (2010), two very important aspects of this wetland project remained: 1) the evaluation of revegetation efforts; and 2) a minimum of one-year of monitoring of the constructed wetland to obtain metrics of success and to determine the utility of the design for potential future wetland construction projects within the Bridge Coastal area. Site visits in 2010 and monthly monitoring surveys in 2011 revealed that the process of plant succession is occurring naturally, mostly with aquatic and terrestrial plants native to the area. A total of 55 plants were documented in the footprint area of the constructed wetlands in 2011: 15 aquatic and 40 terrestrial. Ten non-native plants were recorded, some of which are invasive, mainly in the disturbed areas along the northern edge of the wetland. Removal of these invasive plant species occurred in September 2011 and should continue in the future. Results of the wildlife monitoring in 2011 indicated that multiple species are using the newly constructed wetland habitat. For example, we documented, four species of amphibian and one species of garter snake, several songbird species (including several breeding occurrences), mammal tracks and scat, and several species of bat, all of which were either using the wetland itself or habitats immediately adjacent to the wetland area (e.g., Diversion Reservoir, upland forest). The success of this constructed wetland provides a model that could be applied to other watersheds in BC affected by the impoundment of rivers and creation of reservoirs. To further ensure success of this wetland over time, we recommend additional monitoring surveys to target specific groups over a period of five years, with a decreased monitoring frequency over time. Suggested monitoring includes spring amphibian surveys targeting species at risk (e.g., Red-legged Frog [Rana aurora], Western Toad [Anaxyrus boreas]), the monitoring of bats (Townsend’s Big-eared Bat [Corynorhinus townsendii], Little Brown Myotis [Myotis lucifugus]), rare plant surveys, and general monitoring of wetland and berm integrity. We also recommend the removal of invasive plant species that were documented at the site to improve the integrity of the wetland, riparian areas and terrestrial surroundings. |
| Information Type | report |
| Regional Watershed | Vancouver Island South |
| Sub-watershed if known | Jordan River |
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| Comments | |
| Project status | complete |
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