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HomeMy WebLinkAbout1997.07.07 - 1997 Wetland Study Preliminary FindingsPolaris Engineering and Surveying, Inc. s 1 206 South Uncoln Street, Suite 201 Port Angeles, Washington 98362 360) 452 -53393 FAX: (360) 457 -9319 July 7, 1997 Engineering Department City of Port Townsend 617 Tyler Street Port Townsend, WA 98368 ATTN: Ms Sam Gibboney RE: 1997 Wetland Study Preliminary Findings Sam, The 1997 wetland study was a wetland reconnaissance, the purpose of which was to field verify the nature of the wetland(s) identified in previous work, determine the approximate boundaries of the wetland(s), determine the appropriate State wetland classification(s), and provide an administrative document for City Planning staff to be used in amending the Environmentally Sensitive Ordinance wetland exhibits. This differs from a wetland delineation in that the wetland reconnaissance utilizes the techniques required in the Washington State Wetland Identification and Delineation Manual (March, 1997 issue) to determine the presence of wetland indicators. The reconnaissance differs from a delineation in that a minimum number of data points measured to determine the presence or absence of a wetland and the general geometry of the wetland. In a formal wetland delineation, a greater number of sample points are required to formally establish the presence or absence of a wetland, and the precise wetland boundary. The reconnaissance is an intermediate step between the identification of a potential wetland and the formal delineation required by the State Manual. Sufficient documentation was available to determine the presence of one or more wetlands in the Rainier Street corridor. The inventories wetlands are shown in figure 1. Aerial mapping disclosed standing water bodies in three portions of the corridor, and large depressions in three other locations. Informal wetland studies by Miller (October 13, 1992), Palazzi (E92- 0059; April 22, 1993), (Aug 9, 1994), and Palazzi & Klein (P93 -0056; June 4, 1993) verify the presence of at least four wetlands along Rainier Street between the proposed City filtration site and Old Discovery Road. Miller recognized three wetlands in the Rainier Street corridor between Old Discovery Road and 18`h Street. While the wetlands were shown as independent wetlands, Miller noted the following regarding Wetland 1 at Howard & Old Discovery Road and Wetland 3 at Rainier and Old discovery Road: L-t -O 3--ml Wetland 3 is at the intersection of Rainie treet and Old Discovery Road........ This wetland may be connected with wetland which lies about 900 feet northeast." Miller discovered no wetlands between 13'h and 18* Streets. This is not surprising given the method and time ofyear stated by Miller was: The reconnaissance survey of the City CT and possible pipeline routes was conducted on foot and by vehicle July 9 and 13, 1992. The slow sand filtration site, the City CT and Tri -Area pipeline routes, chlorination site, and future filtration site area were surveyed on foot on August 26, and September 2, 1992." The surveys were made in the dry period of the year and, at least for the Rainier Street corridor between 13'x' & 18' Streets may have been conducted by walking or driving the existing road. Palazzi & Klein flagged a number of surfically connected wetlands betwen 18'h Street and Old Discovery Road. The report of June 4, 1993 makes the following statement regarding the Howard Street corridor: The drainage corridor is quite distinct in most portions. However, it does :run subsurface in at least two areas. As a result, the corridor is actually a series of three isolated wetlands that are not connected via surface hydrologic features. it can be assumed that they are connected however through subsurface hydrology." Further reading the report shows that the separation between report wetlands 2 and 5 is a 50' wide berm. The report states: Because the berm was densely vegetated, it was not posible to evaluate how it was formed. But it is likely to be a result of old logging activities in the area that inadvertentently made a dam across the subtle drainage." The presence of a man -made berm raises the question of whether report wetlands 2 and 5 are actually one wetland artifically divided by a man -made feature. The report continues with a description fo wetland 5: The second wetland is larger than the first and extends more than a mile in a southeasterly direction." Clearly Paiazzi & Klein recognize the presence of a large, connected wetland system in the Howard Street corridor. The description of the large wetland to the southeast includes all those inventoried wetlands within the Rainier, Howard and 12'x' Street corridors. Additional wetlands and depressions exist immediately south of Old Discovery Road and extend easterly on the projection of 12' Street to Thomas Street. A preliminary analysis of the 12 ' Street corridor between McPherson and Thomas Streets by Fleming & Lewellin in 1997 disclosed the presence of a wetland in this area, and that the wetland was hydraulically linked to the wetlands between Eddy & McPherson Streets to the west. The intent of the 1997 study was to study the Rainier and Howard Street corridors and the 12" Street corridor to determine the nature of the wetlands and the degree of hydraulic connection between the wetlands. The study utilized a number of data points to determine the wetland and upland limits, a transect line along Howard Street having data points at 100 foot intervals, analysis of available literature and studies, measurement of seasonal high water where possible, field observation of wetland the boundaries where access was allowed, and estimation of wetland boundaries where access was not allowed. Evidence of prior hydrology was obtained from aerial maps, from field surveys by Polaris Engineering in 1993 and 1994, and from GPS traverses taken in March 1996 and 1997 by CH2M -Hill. The study disclosed not a series of wetlands, but one large, hydraulically connected wetland. Presence or abscence of a wetland was determined using the three criteria of hydrophytic species, hydric soils, and hydrology. Representative pits were made in both wetland and upland areas to determine general limits of soil hydrology. Permission to enter was requested prior to the study, and the wetland boundary was observed on portions of the study area where permision to enter was obtained. An estimated wetland area was entered based upon topographic features for those areas of the study area where permission to enter was not obtained. Please find enclosed three maps related to the 1997 study of the wetlands in Basin 11 in the vicinity of Rainier Street. Contents of the neaps are: Sheet No,_ Contents 1 of 3 1997 Reconnaissance showing wetland data points, non - wetland data points, Howard Street transect line (Data points taken ,at 100' intervals), water bodies shown on 1991 planimetric maps, observed wetland boundary, estimated wetland boundary based upon topography, and the 100' estimated wetland buffer based upon a Category U wetland. 2 of 3 1997 Reconnaissance boundaries versus 1993 boundary established by Pacific Rim & Soils. Part of boundary was flagged and surveyed in field (wetland #2). Remainder ofthe boundary flagged in field but not surveyed. PR &S boundaries on sheet 2 are taken from exhibit from Corps of Engineers permit 94-4 -00259 for City CT Pipeline project. Note that Palazzi & Klein did not hydraulically link their wetland #3 to the Howard Street wetland series. Note also that their study did not evaluate the 12' Street corridor as that was not within their study area. 3 of 3 1997 Reconnaissance boundaries versus 1992 boundary established by Greg Miller (CH2M -Hill) in preliminary wetland evaluation for CT Pipeline project. CH2M -Hill boundaries are taken from Figure 3 of the Miller study. Note that Miller shows no connection between the wetlands nor the presence of the large wetland between 13°i & 18' Street as shown by Palazzi & Klein in 1993. Note also that the Miller study did not evaluate the 12' Street corridor as that was not within his study area. Sheets 1 through 3 of this report are not intended to represent the wetland boundary prepared in the 1997 wetland study by Polaris Engineering and Olympic Wetland Resources. Sheet 1 is intended to show the means of analysis and the basis for the determination of the wetland boundary. Sheet 2 is intended to show the relationship between the Palazzi & Klein wetland boundaries and the 1997 wetland boundary. Likewise, Sheet 3 is intended to show the relationship between the 1992 Miller wetland boundaries and the 1997 wetland boundary. No other inference should be made. The definitive 1997 wetland boundary will be available when the al *p: 1!997. Polaris Engineering and Olympic Wetland Resources is made available on August 4 e formal report will contain an explination of the findings, wetland and b ogs, plant identifications, and wetland rating sheets. The intent ofthe 1997 wetland report is to record a reconnaissance level wetland evaluation. The report will be used by the City as a planning tool to determine whether individual design projects are within a wetland ESA and will, therefore, require a detailed wetland evaluation as part of the project documentation. Nothing within the reconnaissance report should be construed as to relieve project developers from their responsibility under the ESA. The 1997 reconnaissance report is not a formal delineation as required by State law and local ordinance. Please feel free to contact me if you have any questions regarding this submittal. Sincerely, Mike Szatlocky, PE Civil Engineer enc. snaps (3) CC. 97053 rr mc>°azo zmD zz mz-1 zmo,'D Imo yv v= o,. 10 2g -i F*1 — mz °Ezm° lcz mv3$i 29M Uro mjj,;. 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