Hat Creek Restoration Project Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Prepared by Geomorphic Assessment and Preliminary Plans for Woody Debris Placement and Recreation Access Improvements Prepared for California Trout

Project area/objectives Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 PROJECT AREA Highway 299 upstream to Powerhouse riffle OBJECTIVES Provide geomorphic background for restoration activities Develop designs for recreation improvements Develop designs for introduction of large woody debris PRESENTATION OUTLINE Geomorphic overview Large wood restoration Recreation/access improvements

Restoration approach/study methods Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 PROCESS-BASED RESTORATION Replicate the geomorphic and ecosystem processes that create habitat Identify and describe processes Identify human disturbance METHODS Review existing information Stream walk survey Topographic surveys Field surveys of existing wood, and potential wood placement areas Review of instream wood inventory conducted by CalTrout WHY THIS APPROACH? Target species likely to show a positive response Restoration measures less likely to have negative unintended consequences Restoration measures more likely to function over long-term

Geomorphic processes: water and sediment Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Channel form is a reflection of the balance between flow and sediment Source: Rosgen 1996

Water Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Flow very consistent over time Floods are not large Hydropower has limited, short-term effects Agricultural diversion lowers spring flood peaks, spring-summer flow Sources: Kondolf et al. 1994

Sediment: suspended sediment Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 SOURCES Bank erosion, overland flows Episodic, short-term inputs from large-scale events Human disturbances that increase erosion have likely increased suspended sediment supply, but supply relatively low EFFECTS OF DISTURBANCE Increased sedimentation in low velocity areas Limited effect on channel form, but may impact ecology

Sediment: bedload supply Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Large body of prior work due to concerns about sediment wave: Kondolf et al. 1994; Cook and Ellis 1998; Cook 2000) Bedload mostly sand; larger sediment generally can’t be transported due to low slope and lack of large floods Source: Kondolf et al TYPICAL SOURCES Streambank erosion Erosion of tributaries Mass wasting upstream in bypass reaches General conclusions: none of these sources account for bedload

Sediment: bedload supply Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Volcanic events can dramatically increase bedload supply—1915 eruption Transport through the system influences the bedload supply to the project area Flatter areas store sediment, affecting the rate of sediment supply and the size of sediment delivered to the project area Result—over decades following a volcanic event, increase in bedload supply rates to the project area Long intervening periods with low rates of sediment supply Source: Kondolf et al. 1994

Recent sediment wave: influence of human disturbance Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Little effect on overall magnitude of supply Hydropower modifications have disrupted sediment transport in the system Likely a link between Baum Lake and the Powerhouse 2 bypass reach (Cook 2000) Channelization upstream of Cassel in 1950’s likely increased sediment supply, either by increasing transport capacity, erosion of the channelized reach, or both Episodic increases in sediment likely a natural process

Channel sediment reponse Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Hat Creek has limited transport capability due to consistent flow and low slope During periods of high sediment supply, transport capacity is exceeded and channel aggrades Source: Rosgen 1996

Recent sediment wave Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Increased sediment supply resulted in a sediment wave over decadal time scales At any point in the channel, the wave caused an aggradation-degradation event as it passed Total sediment volume in wave 60,000 cy; aggradation average about 1.5 ft (Kondolf et al. 1994) Wave has mostly passed through upper half of project area, crest likely around Wood Duck Island; passes out of project area (Cook 2000)

Channel form Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Cross section rectangular, high width-depth ratio Relatively uniform width and depth Peaty streambanks in low marshy areas Erosion rates low during periods of low sediment supply HUMAN DISTURBANCE Introduction of muskrats significantly increased streambank erosion rates and channel widening--possibly exacerbated by grazing Old Carbon Bridge may have caused widening downstream Riparian shrubs may have been reduced by grazing

Channel form and periods of high sediment supply Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 CHANNEL FORM Depth variable in space and time Width may increase due to higher streambank erosion rates (powerhouse riffle island, Cook 2000) Avulsion possible during severe events (backwaters in historic aerials, Cook 2000) During recent wave, bank instability caused by muskrats may have increased widening Widened areas may retain portions of the wave in narrow, longitudinal bars ECOLOGICAL RESPONSES Burial of aquatic vegetation Aquatic vegetation reestablishment constrained due to high bed mobility Reduction in habitat diversity and complexity

Model of channel function Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Infrequent, large-scale waves of sediment occur naturally Resulting ADE may last decades High rates of streambank erosion during aggradation may result in widening, or side channels and avulsion during severe events As sediment supply decreases, backwater areas fill in with aquatic and emergent vegetation, creating peat and low- lying streambanks Narrow longitudinal bars may persist in widened areas after wave passage, likely to be eventually colonized by aquatic and emergent vegetation and resulting in narrowing

Woody debris-processes of large wood recruitment Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 POSSIBLE MODES OF LARGE WOOD RECRUITMENT TO STREAMS Tree fall Bank erosion Wind throw Soil saturation Snow load Fire Disease Floating Mass wasting

Large wood: recruitment in the project area Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Trees found on streambanks in much of lower half of project area Swampy areas unlikely to grow large trees

Large wood: human disturbance and wood supply Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Timber harvest likely removed potentially recruitable trees Subsequent grazing and management favored conversion to meadows Areas that are currently meadow may have historically had scattered large trees Current load of large wood pieces in the project area, CalTrout surveys) are likely lower than would have occurred naturally

Large wood: restoration opportunities Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 GEOMORPHIC EFFECTS Work with existing process of narrowing in wide areas ECOLOGIC EFFECTS Increase instream habitat diversity and complexity Provide stable substrates for aquatic plant colonization Loafing habitat for turtles Substrates for macroinvertebrates

Large wood: habitat diversity and complexity I Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

Large wood: habitat diversity and complexity II Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

Large wood: habitat diversity and complexity III Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

Large wood: preliminary wood plan Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 Large woody debris loading can vary substantially between streams, even those with similar surrounding forest types, climate, and disturbance histories (Morris 2008) Final density and location determined by budget, aesthetics, fishing access, etc. Design/Construction Considerations Mimic natural tree throw Rootwads will assure stability Disturbance of cultural resources Construction access/disturbance

Large wood: preliminary wood plan Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013 STREAMBANK STABILIZATION Use of wood or other revetments to stabilize streambanks is not recommended Consider biotechnical treatments such as high-density willow planting Control of muskrats should be considered

Recreation Improvements I Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

Recreation Improvements II Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

Recreation Improvements III Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

Recreation Improvements IV Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013