Evaluating the Effectiveness of Riparian Management in B.C. From the Post-Harvest Condition of Stream Channels, Fish Habitats and Adjacent Riparian Areas

British Columbia Ministry of Forests and Range field staff assessed post-harvest stream and riparian conditions of 1441 stream reaches in, or adjacent to, randomly selected cutblocks logged between 1996 and 2006. The objective was to determine whether forest and range practices had been effective in maintaining the “health” or “properly functioning condition” (PFC) of streams and the adjacent riparian areas. PFC is defined as streams and associated riparian areas that: withstand normal peak flood events without experiencing accelerated soil loss, channel movement, or bank movement; filter runoff; store and safely release water; maintain the connectivity of fish habitats in streams and riparian areas so that these habitats are not lost or isolated as a result of management activity; maintain an adequate riparian root network or large woody debris supply; and provide shade and reduce bank microclimate change.  Depending on channel morphology and fish use, 114–120 measurements, estimates, and observations were required to complete a site based on 38–60 specific indicators that supported 11–15 main indicators arranged as a series of checklist questions. A stream was designated in one of three classes of PFC if there were 0-6 problem indicators ("no" responses to the 15 questions).  If there were more than 6 problem indicators the stream was designated as “not properly functioning”.  Eighty-seven percent of the 1441 assessed stream reaches were in one of the three PFC categories. Thirteen percent were deemed NPF.  Of the NPF streams, 72% were small, non-fish-bearing class S6 of headwater areas, followed by the smallest fish-bearing streams (class S4; 16%).  Overall, 19% of all S6 and 11% of all S4 streams were deemed NPF.  Ninety-three percent of the 658 streams classified as fish bearing were in one of the three PFC categories with 7 % NPF. The primary forestry-related causes of impact were:  road associated generation and transport of fine sediments (68%), low levels of riparian tree retention (48%), windthrow (32%), falling and yarding trees across small streams (30%), and harvest-related machine disturbance (26%). Non-forestry-related causes of impact included beetle infestations and fire (30% of all sites) and livestock trampling (9%). Post-harvest monitoring showed some positive results and areas for improvement.  To improve on outcomes, recommendations were made for long-term management of sediments generated and transported by roads, and for increased riparian vegetation retention for small streams based on fish-bearing status, flow regime, and direct connection to either fish habitats or drinking water sources.