Only when the up-slope problems have been addressed, should the in-stream and riparian restoration efforts proceed. Restoration efforts must be coordinated with the road deactivation to prevent elimination of important access routes.
To determine the current stream condition, limiting habitat features, critical reaches, and sites for restoration opportunity, a “Fish Habitat Assessment Procedure” (FHAP) is completed. Based on the FHAP information, site specific, detailed prescriptions (Level II prescriptions) are developed. This will often require the combined efforts of biologists, engineers, geomorphologists, and hydrologists. Once the Level II prescriptions are approved by BC Ministry of Environment (MoE), a permit (Section 9) to work in and about a stream is applied for annually from the Department of Fisheries and Oceans (DFO) and in-stream restoration work proceeds within the established “fish window”.
Generally, in-stream restoration work involves the creation of pools, riffles and glides by installing structures in-stream made of large woody debris (LWD) and/or rock. By securing LWD in place (with cables or boulders) biologists and engineers can temporarily (for 50 years) mimic nature in its creation of pools, riffles and glides. LWD is also a very important source of food for invertebrates, cover and protection from predators. In the high density wood debris jams, there is still a focus on creating a natural pool-riffle-glide frequency, but it is completed by removing excess small woody debris (SWD), and re-locating or re-orienting LWD.
One of the limiting factors for fish production in degraded streams can be the lack of quality spawning gravel. Once the streams have been restored through removal of road barriers, SWD, and addition of LWD complexing, the stream requires time to flush out fine organics that have been allowed to settle and accumulate over the years. After two or three years, when the majority of the fine organics have been flushed through, replacement spawning gravel can be added.
Central Westcoast Forest Society uses a four phased approach for instream & riparian restoration:
- Phase 1: Removal of small woody debris (SWD) and reorienting the existing large woody debris (LWD).
- Phase 2: Maintenance, monitoring, and addition of LWD in deficient areas.
- Phase 3: Addition of spawning gravel in deficient areas. This can only be done after water flow has had sufficient time to scour out accumulated organics, may possibly be implemented during phase 2. Stream work is not considered "comoplete" until phases: 1, 2, and 3 have been addressed.
- Phase 4: Riparian restoration (can be completed concurrently with phase 2 and 3).