Chehalis Basin Strategy

Transcription

1 Chehalis Basin Strategy Presented by Marc Hayes, Julie Tyson, and Keith Douville September 22, photo courtesy of The Chronicle, Centralia, Washington

2 Survey Methods Visual encounter; 3-5 surveyors; 28 May-28 July

3 Survey Methods Surveyed wetted mainstem and all connected and disconnected Off-channel areas created as hydrograph drops Breeding sites georeferenced and associated species noted Connected Disconnected 3

4 Survey Footprint Surveyed Units River Miles River Kilometers Chehalis River Mainstem Below proposed reservoir footprint In proposed reservoir footprint Above proposed reservoir footprint Chehalis River Mainstem Totals Major Tributaries Big Creek Crim Creek Lester Creek Roger Creek Thrash Creek Major Tributary Totals Grand Totals

5 Target Species Western toad most frequently recorded breeding target species Found at 162 sites; a minimum of 261 egg masses represented Coastal tailed frog and Dunn s salamander only other target species found Only 2 CTFs and 2 Dunn s found Survey approach not appropriate for CTF and Dunn s detection 5

6 Evidence of Western Toad Breeding Large Tadpole Aggregations Breeding Toads Egg Mass String Segment 6

7 Western Toad Breeding Estimates Location Relative to Potential Reservoir Footprint Below potential reservoir footprint In potential reservoir footprint Above potential reservoir footprint Breeding Category Breeding location Egg Mass Estimate Breeding location Egg Mass Estimate Breeding location Egg Mass Estimate Number (n =) Number per kilometer (n/km) Number per mile (n/km)

8 Supplementary Surveys Low frequency of toad breeding sites below the proposed dam footprint led to supplementary surveys downstream Only 6 sites with toad tadpoles were found in the 10.5 mi (16.9 km) of supplementary surveys Supplementary survey results need verification during toad breeding period 8

9 Non-Target Amphibian Species Species Columbia torrent salamander (Rhyacotriton kezeri) Number of Instream Off-channel Locations where Observed Number of Individuals Observed 4 28 Northern red-legged frog (Rana aurora) 1 2 Pacific treefrog (Pseudacris regilla) Roughskin newt (Taricha granulosa) 4 10 Western red-backed salamander (Plethodon vehiculum) 2 2 Five non-target amphibian species were recorded during instream surveys All non-target amphibians species were recorded at 7 or fewer sites 9

10 Fish Species Species Coho salmon (Oncorhynchus kisutch) fry and young juveniles Daces (Rhinichthys sp.) Unidentified Lamprey (Lampetra sp.) - juvenile Unidentified Sculpin (Cottus sp.) Qualitative Level of Observation Common Frequent Occasional Occasional One target fish fry and young juveniles of coho salmon were commonly observed in connected off-channel pools Daces were the most frequently observed fish in offchannel pools used for western toad breeding 10

11 Summary Western toad breeding extensive in upper Chehalis mainstem This contrasts strikingly with lack of western toad breeding in floodplain off-channel habitats No western toad breeding observed in upper mainstem tributaries More western toad breeding seems to occur within the potential reservoir footprint Uncertainty in the latter statement relates to the timing of downstream surveys Coho salmon fry and juveniles common in pools with connections to the upper Chehalis mainstream A suite of non-target amphibian and fish species are variably encountered in mainstem off-channel habitats 11

12 Questions/Discussion 12