[env-trinity] Fw: Feb 25 Webinar - Elements of the natural flow regime for consideration in management of regulated rivers

[Tom Stokely]

  ----- Forwarded Message ----- From: Hetrick, Nick <nick_hetrick at fws.gov>Sent: Friday, February 19, 2021, 5:30:24 PM PSTSubject: Feb 25 Webinar - Elements of the natural flow regime for consideration in management of regulated rivers 
  
Klamath River Fish Health Enthusiasts...  

We are pleased to introduce a new learning opportunity to enhance scientific and technical exchange. 

Event Information. Exploring the role of the natural hydrograph in riverine ecology: Elements of the natural flow regime for consideration in management of regulated rivers 

Thursday, February 25, 2021 12:00 pm Pacific Standard Time  

Damon Goodman and Nicholas Som, USFWS, Arcata, CA 

The Webinar home page is here: FWCO Webinar Series Link.  On this webpage, individuals can register to attend talks and view archived presentations from this webinar series. 

Abstract. Flow regimes are a key driver in the ecology of riverine systems world-wide and directly influence the habitats and behaviors of aquatic species. Streamflows provide biological cues and a template for habitats of aquatic organisms by influencing the wetted channel extent, the distribution of water depths and velocities and the interaction with substrate, vegetation and the adjacent bank. The distribution and spatial arrangement of hydraulic variables are dynamic and change with streamflow, a process inherent to free-flowing rivers that is, at times, overlooked when evaluating the effects of managed flow regimes on habitats available to aquatic organisms. This is exemplified by the increase in availability and spatial variation in Chinook Salmon spawning habitats associated with naturally ascending fall baseflows. We found this component of the natural hydrograph to provide a benefit across a range of channel forms and hydrologic regimes. Naturally ascending baseflows also provide ecological benefits during springtime and have been associated with providing additional habitat that temporally overlaps with fry emergence and times critical for development of juvenile salmonids. Streamflow variation induced by winter and spring storm events has also been associated with benefits to ecological processes. Juvenile Pacific Lamprey have a punctuated seaward migration with 90% of individuals outmigrating in a series of large schools. We found strong evidence these migration clusters are associated with rain events, a surrogate for streamflow, with over 90% of emigrants caught during an event and the two subsequent days. The importance of these peak streamflow events is also associated with fish disease management where peak streamflows have been associated with sediment transport, and the subsequent reduction in disease mortality risk for salmonids. These examples provide support for the application of new management tools to support species conservation, such as real-time streamflow management, that integrate elements of the natural flow regime into dam release strategies.  

 



Nicholas J. HetrickFish & Aquatic Conservation Program LeadArcata Fish & Wildlife Office, USFWSOffice (707) 822-7201Cell (707) 267-5856(due to the COVID-19 pandemic, I am teleworking and can be reached by cell or email)   
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