Arising from our priority-setting framework outlined in our Eco-Cultural Restoration Plan, we have chosen to begin wetland enhancement along the lower Alouette River. Prior to European arrival, the Alouette River was a prominent feature within what was once a very large and productive wetland, covering all the area now called the ‘Pitt Polder’ and beyond. This wetland was comprised of the extensive floodplains of the Alouette, Pitt, and Fraser Rivers, intersected by a complex mosaic of bogs, swamps, marshes, and sloughs. Katzie fished for white sturgeon and salmon in the Alouette River, while its floodplain supported abundant waterbirds, wapato, tule, berries, and many other resources.
River floodplains are special places. A ‘floodplain’ refers to the area along rivers that regularly floods. In the lower mainland valley, rivers flood every year due to ‘freshet’, the increase in water volume due to snow that has melted from inland areas and from the mountains above the valley. Freshet water typically picks up and carries rich nutrients as it travels. Thus prior to diking, the floodplains of all rivers in the Lower Mainland were composed of very nutrient-rich soils that supported a highly biodiverse community.
Since about 1890, the natural extent of the floodplain of the lower Alouette River has been highly curtailed by dikes on either side of the river. Diking resulted in major losses in the area of floodplain habitat, combined with simplified and therefore lower quality aquatic and riparian habitat within the dikes. Currently, the floodplain of the Alouette river is restricted to a narrow flat meadow, about 300 m at its widest and approximately 80% covered by invasive reed canary grass.
In addition to diking, the lower Alouette River has also been impacted by the Alouette River hydro-electric dam, which was constructed in 1928. Due to reduced water flow after the dam was constructed, several salmonid species were lost from the Alouette River. All salmonids have returned to the Alouette River as a result of a hatchery program, increased water flow from the dam, and ongoing monitoring. These efforts have been the result of successful partnerships between the Katzie First Nation, Alouette River Management Society, BC Hydro and other organizations. Though these negative impacts of the dam have been lessened, the dam continues to block the downstream delivery of large pieces of dead wood, which has likely caused a significant reduction in the volume of dead wood in aquatic and riparian areas along the lower Alouette River.
Dead wood is a vital component of habitat for many species across diverse types of ecosystems. Within rivers, large pieces of dead wood create the pools and areas of slower-moving water so important as rearing habitat for juvenile salmon. Algae growing on dead wood in water provides forage for aquatic insects, which in turn provide forage for fish and amphibians. Dead wood protruding from water provides sun-basking areas for turtles, and safe roosting sites away from shorelines for water birds like great blue herons and ducks. Dead wood in riparian areas serves a similar role, as places of refuge for amphibians and small mammals and roost sites for birds.
To compensate for these negative impacts to the Alouette River over the past 130 years, our restoration actions include creating marsh habitat, anchoring large pieces of dead wood, planting native vegetation, and the installation of bird and bat shelter boxes. We are also planting species of cultural value to Katzie, particularly wapato and tule.
In 2016, we completed marsh restoration at two sites adjacent to Harris Road along the lower Alouette River. We created marsh habitat by excavating the meadow covered by reed canary grass to a lower elevation, which allowed flooding from the river. In excavated areas, we planted native aquatic species, including wapato and tule. In 2017, we will be working to create and enhance wetland habitat at a site near Neaves Road.
Please visit our enhancement sites and tell us what you think!