Monitoring Impacts of the Okanagan Mountain Park Fire on Hydrological
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EvaluationsEvaluations ofof ImpactsImpacts ofof thethe OkanaganOkanagan MountainMountain ParkPark FireFire onon InIn--streamstream WoodWood andand OtherOther WatershedWatershed ProcessesProcesses Adam Wei Earth and Environmental Science University of British Columbia Okanagan Kelowna, British Columbia, Canada (Presentation at the Watershed Conference, South Carolina, USA, 2006) TopicsTopics toto bebe coveredcovered • Rationale for the project • Long-term monitoring approach • Preliminary results RationaleRationale forfor thethe projectproject • A big picture: forest-water-fish interaction for BC • Disturbance ecology – Wildfire and pine beetle infestation – Emulation of natural disturbance? – Need to know impacts of natural disturbance • In-stream wood (LWD) ecological importance – LWD--morphology—aquatic habitat—fish – Large LWD variability in space and time – Lack of long-term LWD studies There are about 9000 forest fires recorded annually in Canada. An average of 2.1 million hectares are burned every year; virtually all of it is boreal forest. On average, 2000 occurred each year, 50% by man and 50% by lighting Total Area Affected by Mountain Pine Beetle in Western Canada 2001: Mountain pine beetle damage LWD as cover, Salmon Arm fire, 1998 Channel morphology, 90 years after fire, Upper Penticton cr. LWDLWD rolerole && managementmanagement paradigmparadigm • Aquatic environment – Channel morphology & fish habitat – Diversity of hydraulic flows – Sediment trapping – Nutrients & its long-term release – Bank erosion prevention – Paradigm shift: LWD clean-up – LWD protection--?? LWD loading Pulse Fire 20 100 yr A theoretical LWD pulse and dynamics over an average fire interval in lodgepole pine forests, BC interior (a) UNDISTURBED RIPARIAN FOREST INTENSIVE TREE/SNAG REMOVAL ACCELERATED SNAG FAILURE NORMAL SNAG FAILURE ? RIPARIAN CWD RECRUITMENT 0 t 0 t 1 t 2 t 3 TIME (b) UNDISTURBED RIPARIAN FOREST INTENSIVE TREE/SNAG REMOVAL NATURAL DISTURBANCE ? IN-STREAM CWD LOAD IN-STREAM 0 t 0 t 1 t 2 t 3 TIME Generalized models of LWD loads & recruitment for small streams (Bragg 2000) G Okanagan Mountain Park Fire Summer, 2003 www.castanet.net www.castanet.net A unique opportunity for long-term monitoring Interior Douglas-fir biogeoclimatic zone Long-term Monitoring Approach: 3 fire sites and 3 control sites FieldField methodsmethods (1)(1) • Six sites (3 fire & 3 old growth / control sites) • A 100m length of reach for each site • LWD (D > 10cm and L > 1m) • All LWD pieces were tagged • For each LWD piece, decay state, orientation, position, stability, input source and function were documented FieldField methodsmethods (2)(2) • LWD locations (coordinates and elevation) were recorded using the total station Goody Creek, Okanagan Mountain Park CalculationsCalculations (1)(1) • LWD recruitment (input) - all new pieces appeared in the study reach in the next year’s survey • LWD output – all pieces with the tag number were disappeared in the next year’s survey CalculationsCalculations (2)(2) • The centroid of each LWD was calculated based on the X coordinate and Y coordinate of the piece • The difference of the centroid location of the same LWD in the two years’ surveys was recognized as the movement of the piece. PreliminaryPreliminary results:results: annualannual inputinput andand outputoutput ofof LWDLWD Site Site LWD LWD Input Output Input Output name type Number (1) Number (2) LWD LWD Volume Volume (piece) (piece) (piece) (piece) (m3) (m3) Bellevue Fire 24 32 8 0 1.26 0 Deeper Fire 41 42 2 1 0.132 0.017 Goode Fire 41 44 4 1 0.3814 0.009 Greata Control 58 55 4 7 0.0734 0.131 Jack Control 23 25 3 1 0.1983 0.011 McDougall Control 87 82 0 5 0 0.312 PreliminaryPreliminary results:results: transporttransport ofof LWDLWD Site Site Total Moved % Longest Mean name type piece piece Distance moved (m) distance (m) Bellevue Fire 24 4 16.7 56.7 31.3 Deeper Fire 41 5 12.2 32.5 20.4 Goode Fire 41 4 9.8 13.0 9.6 Greata Control 58 13 22.4 23.8 16.1 Jack Control 23 4 17.4 26.3 17.6 McDougall Control 87 11 12.6 20.9 12.7 NothingNothing concluded,concluded, justjust observationsobservations • On average, LWD loading is increased in the fired sites while it is in the relatively balanced condition in the control sites • About 10-20% of wood pieces were transported, with the 10-20 m distances • There were no large LWD fluxes immediately after fires Research Program at UBC Okanagna: Disturbance & Watershed Processes Research Group PartnersPartners UBC Ministries Forest Industries (Riverside, Gorman Bros.) Consulting (Dobson Engineering) FORREX OtherOther topicstopics relatedrelated toto thethe firefire :: • Effects on hydrology and water Quality Jeff Curtis & Adam Wei (long-term monitoring) • Effects on soil repellence and erosion David Scott (3 years or longer) 8 7 Clark Deeper 6 5 4 Y, m3/ha/dY, 3 2 1 0 2/23/2004 3/14/2004 4/3/2004 4/23/2004 5/13/2004 6/2/2004 6/22/2004 7/12/2004 Date 200.00 180.00 160.00 140.00 120.00 100.00 K, g/ha/d K, 80.00 60.00 40.00 20.00 0.00 2/23/2004 3/14/2004 4/3/2004 4/23/2004 5/13/2004 6/2/2004 6/22/2004 7/12/2004 date Thank you!.