Sunday, October 18, 2009

Comments on Jamestown Villas erosion controls

From Mike Mullen,

was a difficult but by no means impossible construction site.
1) poor drainage planning - detention ponds and a drainage system
directing runoff to them should be in place before there is any mass
grading save for that needed to create the pond and drainage system -
in one of the pictures a large amount of runoff was bypassing the
drainage system - why?

 2) inadequate project phasing - project phasing should get the sediment ponds
and drainage in place first, then the access roads and then phase in areas
where dwellings are to be located - from the aerials it does not appear
that this happened
3) inadequate erosion control - the perimeter slopes did not appear to
have any erosion control, slopes this steep need erosion control blankets
and a drainage system that keeps water off the slopes
4) excessive dependence upon silt fence - silt fence is a stop-gap solution
when erosion control fails or when it rains before vegetation or mulcj can
be put in place - unfortunately it is seen as a cure all by the unknowing -
anytime I see double lines of silt fence I immediately sense drainage
system problems or failure and inadequate or absent erosion control
5) improper placement of silt fence - it was hard to tell but it looked like
the silt fence ran up and down the hill in places and was not on the contours -
also, in areas this steep silt fence should have wire backing - I failed to see
it but perhaps it was present - it wouldn't have mattered anyway as the silt
fence was not adequately trenched in
6) improper installation of silt fence - the silt fence did not appear to be on the
contours, was not properly trenched in, was probably not the proper type of fence
and there was little flat area for water to pond behind the fence

It is impossible to say what parties are at fault - was it flawed engineering (was there
any engineering)?, did the contractor fail to install measures in a timely manner
where and how they were designed and specified in the plan?, did the engineer
inspect the site or have a designated person inspect the site routinely to confirm
that measures were properly installed and maintained.

While it is impossible to say why the project was screwed up or who is responsible
it does appear that the responsible regulatory entities let the situation get out of hand.

Preventing more offsite transport of pollutants should be the first priority. The second
priority should be mitigation of the damage already done. But will anyone be willing
to see that the mitigation is done. And, if post-construction planning and BMPs are
as lacking as construction BMPs appear to have been (given the amount of accumulated
sediment) it appears that damage to the stream will continue with ongoing degradation.

Stream restoration is an expensive measure but in some states the developer would
have to pay for removal of the sediment and any stream restoration deemed necessary
for restoration of the stream to as near as possible pre-development conditions.
However, in these states where state and local environmental regulators are more
proactive it is much less likelt that this mess would have been allowed. But, this is
Alabama. ADEM is reactive not proactive and streams are being damaged and
"destroyed" as this one has been all across Alabama.

Michael William Mullen, CPESC
Choctawhatchee Riverkeeper

CPESC - Certified Professional in Erosion and Sediment Control.
I have been a CPESC since 2000. My registration number is 2129.

That means that I have 1) met certain basic requirements (education,
experience etc.), 2) have passed the CPESC examination and
3) have maintained professional development education requirements.

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