Loading...
HomeMy WebLinkAboutOTAK Secondary Review Memo - 4-3-14 - SNTechnical Memorandum K:\project\32300\32385A\Reports\Critical Areas Review Memo_2014_0403.doc 10230 NE Points Drive Suite 400 Kirkland, WA 98033 Phone (425) 822-4446 Fax (425) 827-9577 This review pertains to the Preliminary Plat application for the Reserve at Tiffany Park (City of Renton LUA13-001572) submitted by the applicant, Novastar Development, Inc., to the City of Renton (City). The proposed Reserve at Tiffany Park is located generally to the east of Tiffany Park, to the north of SE 158th Street, and south and west of Pierce Avenue SE. Otak has been asked by the City of Renton (the City) to review the submitted critical areas document and to provide comments regarding its applicability to the Renton Municipal Code (RMC), specifically, Section 4-3- 050, Critical Areas Regulations. The following documents were reviewed in terms of compliance with the critical areas sections of the City code:  Wetland Determination: Reserve at Tiffany Park, prepared by C. Gary Schulz, dated February 28, 2014;  Plan set for the Reserve at Tiffany Park Preliminary Plat, prepared by Barghausen Consulting Engineers, Inc., signed February 27, 2014.  Technical Information Report, prepared by Barghausen Consulting Engineers, Inc., dated November 12, 2013, and revised February 24, 2014. The Wetland Determination identifies three Category 2 wetlands and one Category 3 wetland on the site, which are required to have 50-foot and 25-foot buffers, respectively. The report indicates that wetland buffer averaging is proposed for the project site, and outlines the rationale for meeting the requirements for buffer averaging described in the RMC. To: Rocale Timmons, Senior Planner City of Renton - Current Planning From: Darcey Miller, Senior Wetland Scientist (425) 739-7977 Copies: Date: April 3, 2014 Subject: Reserve at Tiffany Park Wetland Delineation Review Project No.: 32385.A Rocale Timmons, Senior Planner, City of Renton Page 2 Reserve at Tiffany Park Wetland Review April 3, 2014 K:\project\32300\32385A\Reports\Critical Areas Review Memo_2014_0403.doc Two Otak wetland biologists visited the site on March 17, 2014, to confirm whether the wetland delineation was consistent with the Washington State Wetlands Identification and Delineation Manual (Ecology 1997), as required by the RMC. An Otak biologist made an additional site visit on March 31, 2014. Please note that the wetland delineation was performed in June 2013, whereas the rainfall amount as of March 17, 2014, was approximately 5.58 inches above the normal amount for March (National Weather Service); and on March 31, 2014 was 5.85 inches above normal for March. Comment 1 – Delineation Method The wetland determination report cites the US Army Corps of Engineers wetland delineation manuals (1987 and 2010 supplement) for the methodology used. However, the Washington State Wetlands Identification and Delineation Manual (Ecology 1997) is required by RMC 4-3-050.M.4.a. Recommendation: The applicant should ensure that the wetland delineation is consistent with the methodology required by the RMC. Comment 2 – Survey Map We have not seen a survey map showing all of the wetland flags, which is necessary for confirming the wetland delineation. As discussed below, some wetland flags were not found in the field; however, if we have a detailed map and some of the flags remain, all of those missing flags may not need to be replaced. Recommendation: The applicant should submit a map showing all of the surveyed wetland flags (from June 2013 and any upcoming revisions). In addition, missing wetland flags should be replaced as deemed necessary for Otak’s confirmation of the wetland edges. Comment 3 – Wetland A We agree with portions of Wetland A’s delineated edges. However, we could not find some of the flags (including Wetland A-1) in the southern part of the wetland. It appears that the wetland areas extend farther out than the delineated edge, specifically near Flags A-1, A-3, A-5, and A-6. In these areas, we observed hydrophytic vegetation (if any plants at all), hydric soils, and wetland hydrology (mainly inundation). On March 17, 2014, in some areas that appeared to be outside of the delineated (flagged) wetland, inundation was over 1 foot deep during our site visit (see Photograph 1). We agree that Wetland A meets the criteria outlined in the RMC for a Category 2 wetland, which is required to have a 50-foot buffer. Recommendation: Wetland A should be reexamined and any differing edges re-flagged during the early growing season (before mid-May). Any changes to the wetland should be included in the revised Wetland Determination Report and project plans. Rocale Timmons, Senior Planner, City of Renton Page 3 Reserve at Tiffany Park Wetland Review April 3, 2014 K:\project\32300\32385A\Reports\Critical Areas Review Memo_2014_0403.doc Comment 4 – Wetlands B and C During our site visits, standing water extended generally 10 to 70 feet farther than the delineated edges of Wetlands B and C. In addition, Wetlands B and C are not separated by upland area; they appear to be part of the same wetland. On March 17, 2014, inundation ranged from several inches to 1.5 feet deep in areas that may be outside of the delineated wetland edge. Hydrophytic vegetation (mainly salmonberry and red alder) and hydric soils were also observed in the majority of these areas. We agree that Wetland C meets the criteria outlined in the RMC for a Category 2 wetland, which is required to have a 50-foot buffer; however, because Wetlands B and C are connected (one wetland), the area flagged as Wetland B would also be considered a Category 2. Recommendation: Wetlands B and C should be reexamined and any differing edges re-flagged during the early growing season (before mid-May). Confirm the rating and buffer size for Wetland B. Any changes to the wetlands should be included in the revised Wetland Determination Report and project plans. Comment 5 – Wetland D We agree with the majority of the wetland flag locations on Wetland D, although the wetland appears to extend approximately 25 feet to the south of Flags D-3 and D-4. We agree that Wetland D meets the criteria outlined in the RMC for a Category 2 wetland. Recommendation: The wetland should be reexamined and any differing edges re-flagged during the early growing season (before mid-May). Any changes to the wetland should be included in the revised Wetland Determination Report and project plans. Comment 6 – Offsite Wetland (SW side Mercer Island Pipeline ROW) An offsite wetland adjacent to the Reserve at Tiffany Park site was observed on the southwest side of the Mercer Island Pipeline Right-of-way (see Photograph 2). The northwest end of the wetland is southwest of (in line with) 18th Court SE. This linear wetland is approximately 150 to 200 feet long and contains hydrophytic vegetation (creeping buttercup, reed canarygrass, and other grasses) and hydric soils. Wetland hydrology observed on March 17, 2014, ranged from saturation at the surface to saturation at 4 inches below the surface. This wetland likely meets the criteria in the RMC for a Category 3 wetland, which is required to have a 25-foot buffer. Recommendation: If permission is granted from the offsite landowner, the wetland should be delineated, classified, and added to the revised Wetland Determination Report and plans. If permission for delineation is not received, the wetland location should be estimated and shown on the plans, along with the buffer. Rocale Timmons, Senior Planner, City of Renton Page 4 Reserve at Tiffany Park Wetland Review April 3, 2014 K:\project\32300\32385A\Reports\Critical Areas Review Memo_2014_0403.doc Comment 7 – Offsite Wetlands (NE side Mercer Island Pipeline ROW) Several offsite wetlands were observed on the northeast side of the Mercer Island Pipeline Right-of- way (northeast of the gravel access road). These wetlands appear to be Category 3 wetlands; if so, they are likely far enough away so that their 25-foot buffers do not extend onto the project site. Recommendation: The applicant should confirm that buffers from these offsite wetlands do not extend onto the property. Comment 8 –Wetland in Southwest Corner of Site A wetland was observed in the southwest corner of the site, to the north of SE 18th Street and southeast of the adjacent development’s fence. The area was dominated by salmonberry, Himalayan blackberry, and reed canarygrass. On March 17, 2014, hydric soils and up to 4 inches of inundation were observed, and water was draining from the wetland onto the sidewalk along the north side of SE 18th Street. Recommendation: The wetland (if it is determined to be one) should be delineated, classified, and added to the revised Wetland Determination Report and project plans. Comment 9 – Flowpath from Wetland B During our March 17, 2014 site visit, water was observed flowing generally west out of Wetland B to the southwest corner of the project site (see Photographs 3, 4, and 5), then offsite into the Cedar River Pipeline Right-of-way. The wetted width of the flowpath onsite on March 17th was approximately 3 to 6 feet, and the water depth was 1 to 3 inches. Vegetation on the edges of the stream generally consists of upland species such as Indian plum. A defined stream channel with bed and banks was not observed. Sorted gravels were observed in several small portions of the flowpath; however, these gravels were generally angular and therefore have not been subject to flow strong enough to round their edges. During our March 31, 2014 site visit, no water was observed along the flowpath that had been observed on March 17th. Standing water was present at Wetland B (beyond the flagged wetland edge), but no flowing surface water was observed exiting the wetland. No streams are mapped on or adjacent to the site. The closest stream is Ginger Creek, approximately 800 feet offsite to the west. Ginger Creek is a Class 4 tributary to the Cedar River, per RMC Figure 4-3-050-Q4 (Streams and Lakes). Given the above information, it is our opinion that water flows through this area only during/after high rainfall events, drains quickly, and that the area does not meet the definition of a stream. Recommendation: No action is necessary. Rocale Timmons, Senior Planner, City of Renton Page 5 Reserve at Tiffany Park Wetland Review April 3, 2014 K:\project\32300\32385A\Reports\Critical Areas Review Memo_2014_0403.doc Comment 10 – Offsite Wetland (Cedar River Pipeline ROW) The flowpath described in Comment 9 drains into the Cedar River Pipeline ROW, to the southwest of the southwest corner of the Tiffany Park site. Inundation was observed in the area, as well as FAC or wetter vegetation and potentially hydric soils; therefore, the area appears to be a wetland (see Photograph 6). Recommendation: The wetland (if it is determined to be one) should be delineated, classified, and added to the revised Wetland Determination Report and plans. Comment 11 – Buffer Averaging The buffer averaging proposal in the Wetland Determination Report has demonstrated that it meets all of the requirements in RMC 4-3-050.M.6.f. However, revisions to wetland edges will likely change this proposal. Recommendation: The applicant should revise the buffer averaging proposal to be consistent with the any necessary revisions to the wetland edges and wetland buffers onsite. Comment 12 – Temporary Buffer Impacts Sheets 6 and 7 of the plan set (Preliminary Grading Plan) show disturbed areas in wetland buffers that will result from grading and wall installation. These temporary buffer impacts are not discussed in the Wetland Determination Report, nor are they shown on Figure 2 in the report. Recommendation: The applicant should revise the wetland documentation to discuss all temporary impacts to wetland buffers, including impacts to specific functions and how restoration will replace those functions. A restoration planting plan for the disturbed areas should be provided as part of 60% design. Encl. Photographs Rocale Timmons, Senior Planner, City of Renton Page 6 Reserve at Tiffany Park Wetland Review April 3, 2014 K:\project\32300\32385A\Reports\Critical Areas Review Memo_2014_0403.doc PHOTOGRAPHS Photograph 1: Wetland A, near southern delineated edge (3/17/14) Photograph 2. Offsite wetland on Mercer Island Pipeline ROW, facing SE (3/17/14) Rocale Timmons, Senior Planner, City of Renton Page 7 Reserve at Tiffany Park Wetland Review April 3, 2014 K:\project\32300\32385A\Reports\Critical Areas Review Memo_2014_0403.doc Photograph 3. Flowpath, partially in walking trail (3/17/14) Photograph 4. Flowpath, partially in walking trail (3/31/14) Rocale Timmons, Senior Planner, City of Renton Page 8 Reserve at Tiffany Park Wetland Review April 3, 2014 K:\project\32300\32385A\Reports\Critical Areas Review Memo_2014_0403.doc Photograph 5. Water flowing west out of Wetland B (3/17/14) Photograph 6. Offsite wetland on Cedar River Pipeline ROW, facing SW (3/31/14)