Dam Busters 201

Prof. Snyder’s Answers to Supplemental Questions (not answered during the live webinar)

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1. Does anyone regularly do eDNA - ecosystem metagenome studies for before and after dam removal?

Professor Snyder is not aware of anyone who does this.
 

2. What do you mean that rivers are sediment starved? What are they missing - Is it related to habitat?

It just means that there is little sediment supply, particularly of bedload (sand and gravel, typically) delivered from the watershed to the stream. It's the natural condition in many low-relief, former glaciated watersheds.
 

3. Can you please share some more resources on sediment starvation? I always thought there would be concern about Trout breeding habitat (redds) being filled in by fine sediment.

Yes, that's a concern, but mostly in higher-sediment load places, like the Pacific NW. My next talk for Dam Busters will cover this in more detail! 
 

4. What are the issues and approaches dealing with bridge replacement, debris problems, bridge scour and 100-yr flooding elevations with dam removal projects? 

 Certainly, having a good understanding of how much sediment is stored in the reservoir, and how quickly it will travel downstream after removal is really important.
 

5. Is there a universal or commonly recommended way in which to describe sediment accumulation that normalizes it in such a way as to be proportional to the size of the dam or reservoir?

Not really, but a good way to think about it is this. If you know how much sediment is stored in the reservoir, can you estimate how many years of typical transport that represents, for a given river?

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Read the entire chat from the webinar