Progress on greenway--Nov. 28, 2010

The lower half is finished.  Looking upstream from near Midvale Blvd.

The greenway project--replacing the sewer and creating a riprap channel for floodwaters--is about half finished.  The lateral sewer for 4322 Upland Dr is under construction.

Working in a tight spot, 11/18. No damage to trees on left.

I've been amazed at how careful the contractor--S&L Underground and Trucking--has been with the trees.  Last week, I watched as they dug a trench for a lateral line with a large power shovel.  Both an overhead wire, plus a large tree, were in the way.  But the shovel carefully avoided the obstacles while working quickly. 

So far, only one tree (#9) with damage-->

The half-completed riprap channel will go a long way towards preventing a major sediment spill, should heavy rain occur before the job is finished.

We've been lucky that no heavy rains have occurred since October 24.  The gravel road laid down in the ravine seems quite effective in protecting against erosion during light rain.  However, I'm concerned that if heavy rain occurs, floodwaters will erode the banks of the ravine that are now unprotected.  Where the gravel road tilts to one side or the other, berms of gravel are needed to protect the banks.

A few problems

Despite a good job overall, I did spot a few problems on Nov. 28:

  • The new soil placed on either side of the riprap channel--hidden under the erosion control mat--is uneven. Next spring, soil is going to collapse into the spaces between riprap boulders, making holes. Footing here will be treacherous (See above, 11/18).
  •  A metal hopper was parked closer than 5 feet to a tree (right).  To prevent soil compaction around roots, equipment must be parked more than 5 feet from trees.

  • There's an unprotected pile of soil beside the gravel road in the ravine.  The erosion control plan requires that all stockpiles be protected against erosion.

  • In some places, soil has been spilled onto the riprap.  Next spring, some of this is going to wash into the lake.  I'd like to see more attention given to keeping the riprap channel clean.

  • Concrete under the manhole is cracked.  Acceptable quality?  Click on photos to enlarge.
See all the photos here.

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