20071995 Ver 1_Staff Comments_20080707

Re: wetland creation for mitigation help ~ C~7; I' C

Subject: Re: wetland creation for mitigation help
From: "[e-mail]" <[e-mail]>
Date: Mon, 7 Jul 2008 15:18:22 -0400 (EDT)
To: <[e-mail]>

Hi, Sue. I looked over the mitigation plan for the Hartley Drive
project. Here are my comments:
It's a very small area, which I don't deal with very often. It
appears that the goal is a self-sustaining stormwater treatment wetland
rather than a reference-quality mature forested wetland with diverse
habitat. If that's the case, then the plan is OK. If we want
reference conditions, then the planting & monitoring plans may need to
be modified.
It's good that they are stockpiling topsoil and spreading it by hand
after grading. That should help minimize compaction and maintain some
of the local seed bank.
We generally recommend against planting red maple and sweet gum since
these are opportunistic species that readily volunteer into mitigation
sites, especially with a nearby seed source such as the neighboring
forest at this site. We encourage planting of later successional
species in hopes of "jump starting" succession to move more quickly
toward a functional climax community. I like to see mitig plans that
aim to improve, rather than match, the local system. However, this
site is very small and although I wouldn't consider the plan adequate
for a mitigation bank, it may be appropriate for providing some local
water treatment associated with this project. The proposed shrub &
herbaceous species look good. As far as density, trees for forested
mitigation areas are usually planted on 10 or 12-foot centers, and it
doesn't look like it meets this. However, the success criteria require
85% survival so almost all of the planted trees will need to survive,
which should yield a density at 5 years of over our targeted 260
trees/acre, especially if the densely planted shrubs are considered as
woody stems. Plus with the surrounding forest, there will likely be
many volunteers of red maple & sweet gum. I'd worry more about
invasives (privet) moving in, but removal is in the plan for 5 years,
so that will hopefully allow the planted & more desirable vegetation to
get established.
Since no water table gauge is being installed, they are not going to
be able to show that the hydrology criteria of saturation or inundation
for at least two weeks (p. 11 in the plan) are met. As they
acknowledge in the plan, hydric soil characteristics may or may not
become evident during the monitoring period, so they are basing wetland
hydrology conclusions solely on vegetation. Again, I wouldn't approve
this for a mitigation bank, but it may be acceptable based on the
project size and goals.
As usual, that's a long-winded answer for a simple question - sorry!
Let me know if any of it is unclear, or if I can provide any more
support. Or you can just run screaming in the other direction
Hope to see you soon - at the annual meeting if not before. Take
care,
Tammy
----Original Message----
From: [e-mail]
Date: Jun 30, 2008 12:47
To: "Tammy L Hill"<[e-mail]>
Subj: wetland creation for mitigation help
1 of 2 8/20/2008 1:43 PM

Re: wetland creation for mitigation help

2 of 2 8/20/2008 1:43 PM