Not sure what you are asking or commenting on Tim.  Rock roller dams could 
be a couple (several actually come to me) things depending on your title of 
"rock roller" and the engineer that is designing it.  Typically a rock / 
roller dam is a rock filled base with roller compacted earth over the top - 
essentially creating a roller compacted earth weir dam.  I understand these 
are not used as much anymore because of seepage issues and being more prone 
to overturning.  The term 'rock roller' could also be applied to an 
excavated to rock base, roller compacted earth weir dam.  The other 
alternative could be that your title means a rock fill, concrete grout 
injected, concrete poured or possibly roller compacted concrete (yes - there 
is such a thing) weir (probably) dam.  Another possibility is a rock filled 
or base structure with any variety of fill (earth, concrete) that uses 
'roller gates' to control downstream releases.  Or do you have something 
else in mind?

Stephen

----- Original Message ----- 
From: "Tim Thompson" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, February 11, 2006 11:16 AM
Subject: Rock Roller dams


> This doesn't sound familiar to me but while researching crib dams, I found 
> a lot of dams documented at the NPS HABS_HAER site.
>
> Tim T.
>