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HomeMy WebLinkAboutHruby offsite wetland rating_26 AUG 2011From: Hruby, Tom (ECY) <thru461@ECY.WA.GOV> Sent: Friday, August 26, 2011 6:47 AM To: Scott Luchessa Subject: RE: Rating form questions Scott, You only need 2 of the 3 conditions in SC1.2 to make a Cat. 1 estuarine wetland. I would consider the road and bridge across the channel to be a disturbance so it would not meet the first criterion. I bet the road is built on fill across the wetland except for the bridge. So if the unit has at least ¾ of its circumference with an undisturbed buffer it would be a Cat. 1. It does have tidal channels and a contiguous freshwater wetland so it would meet the last criterion. Tom From: Scott Luchessa [mailto:sluchessa@environcorp.com] Sent: Thursday, August 25, 2011 4:30 PM To: Hruby, Tom (ECY) Subject: RE: Rating form questions Tom, Sorry, I did not elaborate fully enough regarding connectivity, hydrologic regime, or vegetation structure. There is a bridge over the tidal channel (no culverts). So, the entire emergent wetland vegetation association in the aerial photo is tidally influenced. As I have not taken salinity measurements or conducted extensive plant surveys towards the western side of the wetland. I suspect that the greener areas to the west in the aerial are tidal freshwater wetlands, which are farther away from the tidal channel. There is very little topographic relief. Gradient is <1%. There is no Spartina, salt marsh vegetation is present, and I did not see any evidence of diking, ditching, filling, etc . Dominant emergent plants in the emergent plant community next to the bridge include Schoenoplectus tabernaemontani, Distichlis spicata, and Potentilla anserina. As shown in the aerial photograph, there is a large, undisturbed buffer or more than 100 ft around more than ¾ of the wetland. About the only place where it is less than that is near the bridge. Tidal channels and contiguous freshwater wetlands are also present as shown in both the NWI map and aerial photograph. Looks to me like all three conditions in SC 1.2 are met. Attached are a couple of photographs looking upstream from the bridge. Given this additional info, would you agree it is a Category I? Thanks, Scott From: Hruby, Tom (ECY) [mailto:thru461@ECY.WA.GOV] Sent: Thursday, August 25, 2011 12:24 PM To: Scott Luchessa Subject: RE: Rating form questions Scott, This is a difficult one without a site visit. The area to the east of the North-south road is definitely estuarine. BUT it may not be Cat. 1 since I cannot say if it meets at least two of the criteria in SC 1.2. The question is whether the large wetland to the west of the road gets any salt input. I expect there are culverts under the road but if there are tide gates and no salt water gets into the wetland then you probably should treat it as a separate unit. The road and culverts/tide gates act as a break in the water regime unless enough salt water gets through to have some salt tolerant veg on the west side. Finally, you are correct, we cannot rate functions of estuarine wetlands since we don’t have any calibrated models for that. Hope that helps. Tom From: Scott Luchessa [mailto:sluchessa@environcorp.com] Sent: Thursday, August 25, 2011 12:01 PM To: Hruby, Tom (ECY) Subject: Rating form questions Tom, Please confirm my understanding of how the rating form is completed for wetlands that contain an estuarine wetland component that is >10% of the total area of the wetland. For a project I am working on now, the proponent is proposing a combination of onsite and offsite mitigation for unavoidable wetland impacts. The offsite wetland is a complex of estuarine intertidal salt marsh, perhaps tidal freshwater, and also palustrine forested HGM types. The entire wetland complex is >150 acres, according to the NWI map (see attached pdf file). From my aerial photo interpretation and site visits, it is clear that the majority of this is tidally influenced (see attached Google image dated June 11, 2010) and the parts I have been able to observe are salt marsh. My interpretation is that this would be a Category I wetland based on special characteristics. As such, the functions are not rated correct? As always, your help is appreciated. Thanks, Scott ______________________________________ Scott Luchessa Certified Ecologist, M.S. ENVIRON International Corporation 605 First Ave, Suite 300 Seattle, WA 98104 Direct (206) 336-1654 Cell (206) 841-3801 Fax (206) 336-1651 http://www.environcorp.com This message contains information that may be confidential, privileged or otherwise protected by law from disclosure. It is intended for the exclusive use of the Addressee(s). 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