Hat Creek Restoration Project

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

2. Project area/objectives • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

3. Restoration approach/study methods • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

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

5. Water • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

6. Sediment: suspended sediment • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

7. Sediment: bedload supply • 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 • TYPICAL SOURCES • Streambank erosion • Erosion of tributaries • Mass wasting upstream in bypass reaches • General conclusions: none of these sources account for bedload • Source: Kondolf et al. 1994 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

8. Sediment: bedload supply • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

9. Recent sediment wave: influence of human disturbance • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

10. Channel sediment reponse • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

11. Recent sediment wave • 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 2010-2040 (Cook 2000) Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

12. Channel form • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

13. Channel form and periods of high sediment supply • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

14. Model of channel function • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

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

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

17. Large wood: human disturbance and wood supply • 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 (@5 pieces in the project area, CalTrout surveys) are likely lower than would have occurred naturally Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

18. Large wood: restoration opportunities • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

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

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

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

22. Large wood: preliminary wood plan • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

23. Large wood: preliminary wood plan • 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 Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

24. Recreation Improvements I Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

25. Recreation Improvements II Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

26. Recreation Improvements III Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013

27. Recreation Improvements IV Hat Creek Restoration ProjectHatRAC PresentationOctober 29, 2013