20080350 Ver 1_Staff Comments_20080716

Re: question on Erickson Retirement Communities mitigation plan
Subject: Re: question on Erickson Retirement Communities mitigation plan SOC8 03 SO
From: "Tammy.L.Hill" <[e-mail]>
Date: Wed, 16 Jul 2008 12:4832 -0500
To: Alan Johnson <[e-mail]>
Hi, Alan. I just looked at the mitigation plan for this project. Is DWQ requiring
mitigation (looks like impacts are below our threshold)?
If we're approving the mitig plan, I would have the following comments:
1. What is the justification for the 1:1 ratio? The proposed activities are
enhancement and creation (the plan calls it "expansion" or "restoration" but if
there wasn't a wetland there in the past, then it's creation),. which generally have
higher ratios than restoration. Additionally, the mitigation would not satisfy
DWQ's 1:1 restoration or creation requirement. In general, mitigation at 1:1 is a
gamble - if any part of the project is unsuccessful, then the applicant will not
meet minimum regulatory requirements for replacing impacted acreage.
2. The controlled outlet and french drain structures are more engineering than we
usually see in mitigation projects. It appears that the wetland is being
incorporated into the stormwater treatment system for the site, rather than being
established to progress through succession into a reference-quality "natural"
wetland system. This is not a bad thing - it's actually good to use the wetland's
treatment capacity to help clean up runoff from a dense site like this. But if the
wetland would require long-term maintenance, then it may not qualify as mitigation
because it is replacing a natural system with an engineered one. In this case, the
maintenance is planned to be minimal, so it may still qualify as the proposed
enhancement & creation.
3. Monitoring requirements are minimal: 3 years of veg monitoring and hydrology
field observations. This is less than normal for a mitigation project, but may be
adequate for a small herbaceous wetland.
4. There are minor discrepancies regarding the enhancement acreage: page 2 and the
mitigation map say 0.14 acres while page 5 says 0.17 acres.
I think the project is worth doing in order to keep some water quality functions on
the site. However, the applicant may have to mitigate over a larger area, buy bank
credits, or pay into EEP to satisfy the balance of required mitigation.
Let me know if you need any clarification or want to talk about this further. Hope
all's well over your way!
Tammy
Alan Johnson wrote:
I found it...will send up to you for review. It is the erickson retirement
[e-mail] wrote:
Hey, Alan. I don't see the mitig plan here
know about it - I'd like to check it out if
way when you're done.
anywhere. Thanks for letting me
you don't mind sending it this
Thanks & happy Monday,
Tammy
Tammy Hill
Environmental Senior Specialist
NC Division of Water Quality (401/Wetlands)
2321 Crabtree Blvd., Suite 250
Raleigh, NC 27604
919-715-9052 (voice)
1 of 2 7/16/2008 12:55 PM
Re: question on Erickson Retirement Communities mitigation plan
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2 of 2 7/16/2008 12:55 PM