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HomeMy WebLinkAbout821355062 Stormwater MgmtTfrnberiuld A&MJ&g mor 't;, Inc. FORESTRY CONSULTANTS Since 1970 Stormwater Management Plan For Olympic Ridge Estates Compiled by Earl Kong June 15, 2001 290 5th Street P.O. BOX 130 UNION, WA 98592 1-800-775-0795 wtm @ hctc.com www. wtmtrees.com Project Description - The purpose of this Stormwater Management Plan is to ensure that the operation under FPA 2603994 unit #3, meets the standards set by Jefferson County Planning department for erosion control. The FPA was approved on June 11, 2001 by the Department of Natural Resources and provides for a 40 percent thinning operation over 15 acres. The unit contains about 2,700 trees and the thinning operation will remove about 1,000 trees. The cutting of trees in itself does not cause erosion, however the roads and skid roads used for logging, create exposed soil. Therefore increasing the potential for erosion. Surface erosion is the only topic covered in this plan, as the conditions that could create a mass wasting event at the site do not exist. Soils - There are 2 soil series occupying the site, the Indianola series and the Cassolary series. Within the Cassolary series are small inclusions of the Everett series. For consideration of Stormwater Management, all these soils are similar. The Cassolary and the Everett are a gravelly sandy loam and the Indianola soil is a loamy sand. All 3 soils have a rooting depth of about 60 inches. They are excessively drained with rapid permeability. Water erosion is slight when the slopes are nearly flat. Moderate when slopes are about 30%. Severe when slopes exceed 50%. Topography - The project area is occupied by an upland terrace with a slight gully about 1,000 feet long and 300 feet wide. The slopes along the sidewalls of the gully range from 15% to 50%. The area covered by slopes approaching 50% is less than 1%o of the project site. There is no water (flowing or non flowing) or wetlands within or near the project site. Recommendations- In conjunction with Jefferson County's "Large Parcel Erosion Control Plan", the following recommendations are intended to manage Stormwater so that the movement of soil is minimized or prevented. . Stabilization and sediment trapping. Exposed soil should be avoided on slopes greater than 35%. All exposed soil will be stabilized by the application of appropriate BMPs within two days, from October 1 through April 30 and within seven days from May 1 through September 30, after the completion of the project. The appropriate BMPs will include but not be limited to water bars, silt REST PRACTICE · Packet Created: 06/12/20ol ACT IV ITY MAP TOWNSH I P 28 NORTH, RANGE Ol EAST (W.M. ~, S_ECT ION 35 APPL I CAT ION if 2603gg 4' 27 ...- / \ 0 1000 MAP DAT~ J~e ~ 200~ L\\\\\\\\\\\\~ l\\\\\\\\\\%\~J I CONTOUR INTERVAL' NAD 2 7 40 Feet LEGEND' See Instructions DISCLAIMER' See Legend CERTIFIED PROFESSIONAL GEOLOGIST AIPG: 2671 CRAIG K. WHITE, INC. GEOSCIENCES CONSULTING CERTIFIED: AAPG DIVISION OF ENVIRONMENTAl. GEOSCIENCES July 23,2001 Olympic Ridge Estates Commtmity Association 713 Olympic Ridge Dr. Port Ludlow, WA 98365 Attention: Mr. John Mitchell Department of Community Development 621 Sheridan Street Port Townsend, WA 98368 Attention: Mr. John D. Peters Washington Timberland Management P.O. Box 130 Union, WA 98592 Attention: Mr. Gary Hanson, Mr. Earl Kong t JEFFERSON COUNTY DEPT. OF OOM&,IUNITY DEVELOPMENT Subject: Review of Stormwater Management Plan Olympic Ridge Estates FPA # 2603994 (Unit 3) Gentlemen: At the request of Mr. John Mitchell (Olympic Ridge Estates Community Association), we performed a brief site evaluation of the proposed harvest areas for the above-captioned FPA on July 20, 2001. At that time we also reviewed the conditions of the DNR permit, a detailed map of the harvest areas (provided by .Mr. Mitchell), and the requirements of Section 6 of Jefferson County's Unified Development Code (DOE SMM) as it pertains to Stormwater Management. It is our opinion that the Stormwater Management Plan for Olympic Ridge Estates, compiled by Mr. Earl Kong on June 15, 2001 accurately characterizes the soil conditions and topography at the harvest site, and clearly outlines the provisions of the proposed thinning operation. The plan also includes recommendations that would establish adequate buffers, and outlines appropriate steps which, if employed, would provide protection against water runoff and erosion of the affected area. P.O. BOX 3398. SILVERDALE. WA 98383 (360) 8304)718 ,03B 00'oo~ ~%u~medynbsd =q~ q%[~ aouemJo~uoo u~ uo[439J~p Xm d~pun Jo ~m Aq gpem dI~B30 S,I:IOA3AI:::InS ! i i i i i nil j ~ 31INS 'ArM d¥S£I~ [~LE 9NIW33NIgN3 '3NI ,H33 -3Vd i i · 'Z,'LOZ, G'0¢c7, G ~ 'LLD ~ 'gV'b t ri i. '~'L 2~0:~ '.L,Neg ,Oe ' IM~V~39~g ukJ. IqlJ. fl Sa±l~ or, tlOglfl~ ~lOdl~:lO0 £6'0S 'M.PG.O~.OB G O~ 00'O~ ~.B~,O~.~O N '0 ,007., -,, 1 ;~3qYDS 03MO3HD · NM~O 03A3^~nS 31¥~I~I£B3~ S. BO£IO~Y Ii i ii iii i i.i OL¢. ~16 '¥/~ BO.q.A3^Bns JO OB( iii i i ! i i (:3 '~Y 50'7. LI (/, iIJON aa5 > ., · ~'3"j'/t) -. 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