The three options are:
- Bury the stream and replace the sewer--apparently the original plan.
- Leave stream on surface, but reinforce the bank with riprap, and replace the sewer.
- Leave the streambank as is, with possible addition of three small
metalrock dams ("vanes") at the upsgtream end to control erosion. Sewer not replaced--only relined.
- Option 1 (buried stream) involves cutting down at least 55 living trees and 11 dead trees.
- Option 2 (riprap open stream) involves cutting down at least 57 living trees and 11 dead trees.
- Option 3 (leave stream mostly as is) involves cutting only 6 living trees and 1 dead tree.
Update as of 11/29: I don't support any of the current options. I'm closest to supporting Option 3, but it doesn't address the erosion. We need more study, and a new option, Option 4.
I suspect that Option 2 will require larger equipment for both tree cutting and riprapping. With Option 2, corners are cut so the stream becomes more straight.
Questions about the third option
- What to the
metalrock vanes (dams) do? What do they look like?
- Would the vanes control all the erosion? What about existing bank cuts?
- Would any trees need to be cut for lateral sewage lines? Update: Chris Schmidt says that trees that have to be cut for laterals are already included in the diagrams.
- What size equipment is needed to repair the sewage line, and how would it get into the ravine?
- Would any funds be included for terracing or naturescaping to restore damage that does occur
- Has the sewer frozen so far? If not, there's no reason to believe it will freeze in Option 3.