The URL can be used to link to this page

Home My WebLink AboutRobert JohnseineJL1l:ltJ & ASSOCJlA1fE§9 INC. Geotechnical Engineering Mr. Bob Holm Bob Holm Company 4905 -200th Street SE Bothell, WA 98012 Dear Mr. Holm: Engineering Geology November 10, 2008 Subject: Geotechriical Investigation and Recommendations Plat of Pleasant Path 12204-148th Avenue SE. Renton, Washington L&A Job No. 8A098 INTRODUCTION Earth Science We have completed a geotechriical investigation for the site of the subject plat, located at the above address in the unincorporated King County, Washington, just east of the city limits of Renton. The general location of the project site is shown on Plate 1 -Vicinity Map. Over most of the eastern two thirds of the site is a wetland and its buffer zones. We understand that the proposed development for the site is to plat the western portion of the site outside of the wetland buffer zone into eight single-family residential building lots. The site is bounded by 148th Avenue SE to its west and adjoined by residential developments on the other sides. The building lots of the subject plat will be accessed from 148th Avenue SE via a short roadway with a cul-de- sac tum-round in the middle of the to-be-developed western.portion of the site and a driveway from the cul-de-sac to the southern lots. A stormwater detention vault is to be located near the southwest comer of the site to store storm runoff collected over the impervious surfaces of the proposed development of the site. 19213 Kenlake Place NE · Kenmore, Washington 98028 Phone (425) 483-9134 · Fax (425) 486-2746 November I 0, 2008 Plat of Pleasant Path L&A Job No. 8A098 Page2 The purpose of this investigation is to characterize the subsurface conditions of the site and provide geotechnical recommendations for the design of the roadway and driveway and the stormwater detention vault. We did not conduct subsurface exploration on the site with test pits or test borings. Instead, this geotechnical investigation is based on the geologic and soil conditions shown on a published geologic map and our experiences of previous projects in the general area of the subject plat site. Presented in this report are our findings of the subsurface conditions and our recommendations. SITE CONDITIONS SURFACE CONDITIONS The subject plat site is situated on the top of a broad, gentle to very-gentle, westerly to southwesterly declining slope flanking the western fringe of a broad, southeasterly trending highland. A wetland traverses roughly south-southeasterly through the middle of the site. As shown on Plate 2 -Site and Plat Plan, the terrain within the site generally slopes down very gently at 2 to 8 percent grade from its east boundary westward towards the wetland, and again from the wetland towards its west boundary. The site is currently occupied by a single-family residence with a separate garage and a work shop within the northwestern quadrant of the site. We understand these existing structures will be demolished for the proposed development of the site. The area surrounding the existing structures is cleared and covered with sporadic grass. The eastern portion of the site is dotted with young deciduous trees and covered with dense underbrush. GEOLOGIC SETTING AND SOIL CONDITIONS The Geologic Map of the Renton Quadrangle, King County, Washington, by D.R. Mullineaux, · published by U. S. Geological Survey in 1965, was referenced for the geologic and soil· lLlilU & ASSOClIA'lI'ES, lINC. · November 10, 2008 Plat of Pleasant Path L&A Job No. 8A098 Page3 conditions of the subject plat site. According to this publication, the surficial soil unit at and in the vicinity of the site is mapped as Ground Moraine (Qgt), as shown on Plate 3 -Geologic Map. The geology of the Puget Sound Lowland has been modified by the advance and retreat. of several glaciers in the past and subsequent deposits and erosion. The latest glacier advanced to the Puget Sound Lowland is referred to as the Vashon Stade of the Fraser Glaciation, which has occurred during the later stages of the Pleistocene Epoch and retreated from the region some 14,500 years ago. The ground moraine soil unit is composed of a thin layer of ablation till over lodgmont till, deposited by Puget glacial lobe of the Vashon Stade of the Fraser Glaciation. The underlying lodgmont till is generally a compact mixture of unsorted clay, silt, sand, gravel and cobble, commonly referred to as "hard pan". The surficial ablation till is similar to lodgmont till, but is much less compact and coherent. The thickness generally varies from 2 to 4 feet for the ablation till deposit, and 5 to 30 feet for the lodgmont till deposit. The lodgmont till deposit is practically impervious, except local lenses of sand and gravel. It has a compressive strength comparable to that of low-grade concrete and can stand in steep natural or cut slopes for a long· period. The · lodgmont till can provide excellent foundation support with little settlement expected. The overlying ablation till is generally in a looser state, and is more compressible and permeable. GROUNDWATER CONDITION The very-dense, weakly-cemented lodgmont till deposit underlying the site at shallow depth is of extremely low permeability, and would perch stormwater infiltrating into the more permeable surficial soils. The amount of and. the depth to this near-surface ·perched groundwater would fluctuate seasonally, depending on precipitation, surface runoff, ground vegetation cover, site JLJIU & ASSOCIATES, INC. November 10, 2008 Plat of Pleasant Path L&A Job No. 8A098 Page4 utilization, and other factors. The perched groundwater may dry up completely during the dryer summer months and accumulate and rise in the wet winter months. DISCUSSIONS AND RECOMMENDATIONS GENERAL The to-be-developed area in the western portion of the site is most likely mantled by a thin layer of topsoil, underlain by a layer of ablation till of medium-dense silty sand to about 2 to 3 feet deep, which is in tum underlain by a lodgmont till deposit of very-dense, weakly-cemented, gravelly, silty sand with occasional cobble. The to-be-developed area is gently to very-gently sloped . . The underlying very-dense lodgmont till soils are of very-high shear strength and. are capable of providing excellent foundation support to the proposed stormwater detention vault and the residential buildings to be constructed on the site. Conventional footing foundations constructed on or into the lodgmont till soils may be used to support the stormwater detention vault and the buildings. SITE PREPARATION AND GENERAL GRADING Vegetation should be cleared and grubbed within construction limits and should be preserved and maintained beyond construction limits. Topsoil and loose to medium-dense ablation till soils in the to-be-developed areas of the site should be completely stripped down to the very-dense lodgmont till soils within building pads of the building lots, and topsoil and the unsuitable soils in the root zone should be stripped down to the medium-dense ablation soils and/or the lodgmont till soils within the paved roadway/driveway. Fill, if required for grading, should be constructed · on proof-rolled,· unyielding, undisturbed, firm native soils following the stripping of the surficial unsuitable soils. lL:U:lU & ASSOC:nATJES, INC. November 10, 2008 Plat of Pleasant Path L&A Job No. 8A098 Page 5 SEISMIC HAZARD AND DESIGN CONSIDERATION The Puget Sound region is in an active seismic zone. The subject site is underlain at shallow depth by very-dense lodgmont till soils of very-high shear strength. There is a lack of continuous, extensive, static groundwater table at shallow depth under the site. The site is generally gently to very-gently sloped. The combination of the above makes it rather unlikely for · seismic hazards, such as landslides, liquefaction or soil lateral spreading, to occur on the site during strong earthquakes. Therefore, the seismic hazard of the site should be minimal. The residential buildings to be constructed on the site, however, should be designed to withstand seismic forces induced by strong earthquakes. Based on the soil conditions encountered by the test pits, it is our opinion that Seismic Use Group I and Site Class D should be used in the seismic desigri of the proposed residences in accordance with the 2006 International Building Code(IBC). EXCAVATION AND FILL SLOPES Under no circumstance should excavation slopes be steeper than the limits specified by local, state and federal safety regulations if workers have to perform construction work in excavated areas. Unsupported temporary cuts greater than 4 feet in height should be no steeper than lH: 1 V in topsoil and ablation till soils, and no steeper than l/2H: 1 V in the underlying lodgmont till soils. Permanent cut banks should be no steeper than 2H: 1 V in topsoil and ablation till soils, and no steeper than l-l/4H:1V in the underlying very-dense lodgmont till soils. The soil units and the stability of cut slopes should be observed and verified by a geotechnical engineer during excavation. Permanent fill embankments required to support structural or traffic load should be constructed with compacted structural fill placed over undisturbed, proof-rolled, firm, native, fresh_ till soils after the Sllfficial unsuitable soils are completely stripped. Permanent fill to be placed over LIU & ASSOCIATES, INC. November 10, 2008 Plat of Pleasant Path L&A Job No. 8A098 Page6 slopes steeper than 15 percent grade should be retained structurally. The exposed ground exceeding 20 percent grade should be benched with vertical steps not exceeding 4 feet tall after stripping of surficial unsuitable soils and prior to placing structural fill. The slope of permanent fill embankments should be no steeper than 2H:1V. Upon completion, the sloping face of permanent fill embankments should be thoroughly compacted to a non-yielding state with a hoe- pack. The above recommended cut and fill slopes are under the assumption that groundwater seepage would not be encountered during construction. If groundwater is encountered, the construction work should be immediately halted and the slope stability re-evaluated. The slopes may have to be flattened and other measures taken to stabilize the slopes. Stormwater should not allowed to flow uncontrolled over cut and fill slopes. Permanent cut slopes or fill embankments should be seeded and vegetated as soon as possible for erosion protection and long-term stability, and should be covered with clear plastic sheets, as required, to protect them from erosion until the vegetation is fully established. STRUCTURAL FILL Structural fill is the fill that supports structural or traffic load. Structural fill should consist of clean granular soils free of organic, debris and other deleterious substances and with particles not -- larger than three inches. Structural fill should have a moisture content within one percent of its optimum moisture content at the time of placement. The optimum moisture content is the water content in the soils that enable the soils to be compacted to the highest dry density for a given compaction effort. Onsite clean silty sand to gravelly sand soils, meeting the above requirements, may be used as structural fill. . Imported material. to be used as structural fill · should be clean, free-draining, lLJilU & ASSOCJIA'Jl'E§, JINC. November 10, 2008 Plat of Pleasant Path L&A Job No. 8A098 Page 7 granular soils containing no more than 5 percent by weight finer than the No. 200 sieve based on the fraction of the material passing No. 4 sieve, and should have individual particles not larger than three inches. The ground over which structural fill is to be placed should be prepared in accordance with recommendations in the SITE PREPARATION AND GENERAL GRADING and EXCAVATION AND FILL SLOPES sections of this report. Structural fill should be placed in lifts no more than 10 inches thick in its loose state, with each lift compacted to a minimum percentage of the maximum dry density determined by ASTM D1557 (Modified Proctor Method) as follows: Application Within building pads and under foundations Roadway/driveway subgrade Retaining/foundation wall backfill Utility trench backfill STORMWATERDETENTIONVAULT % of Maximum Dry Density 95% 95% for top 3 feet and 90% below 92% 95% for top 4 feet and 90% below An underground concrete detention vault is to be constructed near the southwest comer of the site to store stormwater collected over impervious surfaces of the proposed development of the site. The bottom of the vault is to be at about 8 to 15 feet below the existing ground surface. At such depths, the vault pit would be excavated into the very-dense lodgmont till deposit The vault may be supported on footings founded on the lodgmont till soils and an allowable soil bearing pressure of 4,000 psf may be used for the design of the vault footing foundations. lLlU & ASSOC][ATES, ][NC. November 10, 2008 Plat of Pleasant Path L&A Job No. 8A098 Page& A drain line consisting of perforated, rigid PVC, drain pipe or slotted, corrugated ADS, drain pipe; at least 6 inches in diameter, should be installed at a few inches below bottom of the perimeter footings of the vault walls to intercept and drain away groundwater which may flow towards the vault. The drain line should have sufficient slope (0.5% minimum) to generate flow by gravity, and water collected in the drain line should be tightlined to discharge into a storm sewer line or a suitable stormwater disposal facility. The vault footing drain line should be completely embedded in washed gravel wrapped in a layer· of non-woven filter fabric, such as 140N by Mirafi Inc. or approved equal. A vertical drainage blanket at least 12 inches thick horizontally, consisting of compacted pea gravel or washed gravel, should be placed against the perimeter vault walls. The remaining backfill behind the vertical drainage blanket should be constructed of structural fill. Alternatively, a vertical drain mat, such as Miradrain 6000 by Mirafi Inc. or equivalent, may be placed against the perimeter vault walls in lieu of the gravel vertical drainage blanket. The vertical drainage blanket or drain mat should be hydraulically connected to the drain line at the base of the vault perimeter walls. Sufficient number of cleanouts at strategic locations should be installed for periodical cleaning of the vault wall drain · line to prevent clogging. The perimeter walls of the detention vault would also serve as retaining walls to support cut banks and backfill. The perimeter vault walls capped with a lid would be restrained at their top from horizontal movement and should be designed for at-rest lateral soil pressure. For the condition that groundwater behind the perimeter vault walls can be fully drained by the drain line provided at the base of the walls, we recommend an at-rest soil pressure of 50 pcf equivalent fluid density (EFD) be used for the design of vault perimeter walls. To counter the at-rest soil pressure, a passive lateral soil pressure of 3 7 5 pcf EFD may be used, except that the passive pressure within the top 12 inches of the finish subgrade should be ignored. The above passive pressure assumes the backslope of the walls is level or ascending away from the walls. The at- JL][U & ASS0Cl£A TES, JINC. November 10, 2008 Plat of Pleasant Path L&A Job No. 8A098 Page9 rest soil pressure may also be resisted by the friction force between the footings and the subgrade soils based on a coefficient of friction of 0.55. If the site grades are such that it is not feasible to completely drain groundwater behind the vault walls with a gravity drain line system, the hydrostatic pressure on the perimeter vault walls should also be taken into consideration for the design of the vault perimeter walls. For the condition that a perimeter drain line has to be placed higher than the footing level, the perimeter vault walls should be designed for a lateral soils pressure of 50 pcf EFD above the drain line level and a combined lateral soil and hydrostatic pressure of 80 pcf EFD below the drain line level. The above lateral pressures on the walls may be countered by a passive soil pressure of 375 pcfEFD above the drain line and 210 pcfEFD below. The detention vault should also be designed for seismic loading based on a 100-year seismic event. For seismic design of the detention vault walls, a pseudo static soil pressure diagram of inverted triangle from the finished ground level to the bottom of the foundations should be used. Based ?n the soil conditions in the detention vault area, we recommend the lateral soil pressure at the top of the triangle be 8H psf for a 100-year seismic event, where H is the height from finish grade on top of the vault to bottom of footings in feet. A one-third increase in the above recommended allowable soil bearing pressure may be used when considering the seismic loading condition. The above design parameters are unfactored ultimate values. Proper factors of safety should be applied for the design of the vault walls against sliding and overturning failures. ILllU & ASSOCKATES, ][NC. November 10, ·2008 Plat of Pleasant Path L&A Job No. 8A098 Page 10 PAVED ROADWAY/DRIVEWAY Performance of roadway/driveway pavement is critically related to the conditions of the underlying subgrade soils. We recommend that the subgrade soils under the roadway/driveway be treated and prepared as described in the SITE PREPARATION AND GENERAL EARTHWORK section of this report. Prior to placing base material, the subgrade soils should · be compacted to a non-yielding state with a vibratory roller compactor and proof-rolled with a piece of heavy construction equipment, such as a fully-loaded dump truck. Any areas with excessive flexing or pumping should be over-excavated and re-compacted or replaced with a structural fill or crushed rock placed· and compacted in accordance with the recommendations provided in the STRUCTURAL FILL section of this report. We recommend that a layer of compacted, 7/8-inch crushed rock base (CRB), be placed for the roadway/driveway. This crushed rock base should be at least 6 inches for the roadway off 148th Avenue SE and 4 inches for the driveway off the cul-de-sac end of the roadway. This crushed rock base may be reduced to a 2-to-3-inch layer of leveling course consisting of 7/8-inch crushed rock if the roadway/driveway bases are cut into undisturbed, very-dense, lodgmont till soils .. This crushed rock base should be overlain with. a 3-inch asphalt treated base (A TB) topped by a 2- inch-thick Class B asphalt concrete (AC) surficial course for the roadway and overlain with a 3- inch-thick Class B asphalt concrete (AC) surficial course for the private driveways. RISK EVALUATION STATEMENT The subject site is underlain at shallow depth by very-dense lodgmont till soils. These soils are of very-high shear strength and the site should be quite stable. It is our opinion that if the . recommendations in this report are fully implemented and observed during construction and following the completion of construction, the areas disturbed by construction will be stabilized and will remain stable, and will not increase the potential for soil movement. In our opinion, the LID & A§§OCiA TJE§, INC. November 10, 2008 Plat of Pleasant Path L&A Job No. 8A098 Page 11 risk for damages to the proposed development and from the development to adjacent properties from soil instability should be minimal. LIMITATIONS This report has been prepared for the specific application to this project for the exclusive use by Bob Holm Company and their associates, consultants and contractors. We recommend that this report, in its entirety, be included in the project contract documents for the information of the prospective contractors for their estimating and bidding purposes and for compliance with the recommendations in this report during construction. Tue conclusions and interpretations in this report, however, should not be construed as a warranty of the subsurface conditions. The scope of this investigation does not include subsurface. exploration of the site or services related to construction safety precautions and our recommendations are not intended to direct the contractor's methods, techniques, sequences or procedures, except as specifically described in this report for design considerations. Our geotechnical recommendations are based on the geologic and soil conditions shown on the above-referenced geologic map, and our experience and engineering judgment. Tue conclusions and recommendations are professional opinions derived in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty, expressed or implied, is made. Tue actual subsurface conditions of the site may vruy from those described in this report. Tue nature . and extent of such variations may not become evident until constructio_n starts. If variations appear then, we should be retained to re-evaluate the recommendations of this report, and to verify or modify them in writing prior to proceeding further with the construction of the proposed development of the site. LJIU & ASSOCIATES, ][NC. November 10, 2008 Plat of Pleasant Path L&A Job No. 8A098 Page 12 CLOSURE We are pleased to be of service to you on this project. Please feel free to call us if you have any questions regarding this report or need further consultation. EXPIRES 7 / 17 / Tirree plates attached Yours very truly, LIU & ASSOCIATES, INC. aj):e'-:) J. S. (Julian) Liu, Ph.D., P.E. Consulting Geotechnical Engineer lLIUJ & ASSOCiATJES, INC. 11£ :s. !51 -----.. -SE 111TH ST .... . ...... SE v. 113TH o ,.,., 15500 ::: ST ~ > -< . ~ SE 114TH ST SE SE 116TH ST 14800 -~E 124TH ST SE 125TH ST w 126TH ~ ST > -< 0 " "' ;!; SE 128TH ST 8 SE 129TH w "' PL w > 2ND < ST i= 0 ,, . 0 N a, 15 IJJRO ST ':; M -~ " i= ., ., - LIU & ASSOCIATES, JINC. SE 117TH ST SE>...,__i:, 118TH< .,., U ST i= :1l SE 120TH 1 ST i SE 124TH ST :1 ' ~l ;:; I I i w w ~ ~ > > < < w w ~ ~ i= i= ~ 0 ;!; ~ - SE > > < < i= i= ~ ~ !!) !!) 14800 SE 132ND ST SE 13JRO CT 1w 138TH ,~ > PL < 139TH 0 " PL "' !!) SE \40lll w ~ " " sr 141sr " ,., <I I I I i=l .,, !!)I I I ,,,":JW ST '-q, > <( 14 VICINITY MAP SE : ST I s, ''''"Pi:\ 11 s- ~ ~ 128TH :i: SE · -• 15600 8 w N w =-~ ~ SE 131ST ~ SE 132ND SE PL ~ i= > SE a, < ~ -SE 13! :i§l_H_ 1 0 0 ~ H-C; X >-tsg -:,; SE 141ST ST 8 N SE 142ND :,; ~ ST ~ ST " ' 4/:f'D I !!! 144TH w ~ 15900~...., w -· ~ c; ~ Geotechnical Engineering • Engineering Geology · Earth Science PLAT OF PLEASANT PATH 12204 -148TH AVENUE SE RENTON, WASHINGTON JOB NO. 8A098 DATE 11/10/2008 PLATE _1_ lLIU & ASSOCIATES, INC. Geotechnical Engineering · Engineering Geology · Earth Science GEOLOGIC MAP MAP PLAT OF PLEASANT PATH 12204 -148TH AVENUE SE RENTON, WASHINGTON JOB NO. '8A098 DATE 11/10/2008 PLATE~ ··r=================~ CXTRUOEO CURB : 1 .~5 78--...._ !30 --- 1 3 ~ ~ 1CTION~" . OJ 0 V. SEE "C2.31 FOR ',1/EET a-: 0 --- ~UD(D- CUR:3 7 IS w. ;)" ; • ·1 I j w :, "' " 30' ., v 9 12 <A..L.'1ffl/YV LJM/1.:, IU OC. UCLJl'rll'i IC.ti <!..) BY ORANGE CONSTRUCTION FENCE OR SILT FENCE (TrP.) !'ENCE 1.2· sou n, OF / -PROPERTY UNE .t~ r- 1 ) , / , ,/ 5 0 10 FENCE 1. • PR .,. ,LillJ & ASSOCKA'flE§, JINC. Project · SheetNo._of_· EL6)(1ft,f.£ f'A\/E;M6wf Q$fqt,!p.No. __ _ ' . f'LP-1 Of-: f'Li:;:A.sAtlT f'A1J:l Geotechnical Engineering • Engineering Geology • Earth Science 19213 KENLAKE PLACE NE • KENMORE, WA 98028 PHONE: (425) 483-9134 FAX: (425) 486-2746 --~--.---,--~-~~Job No ~Ao"1 B By .J.$1._. Dato ~121 / oj Ck'd by DESIGN CALCULATIONS ROADWAY FLEXIBLE PAVEMENT PLAT OF PLEASANT PATH 12204-148TH AVENUE SE RENTON, WASHINGTON ! ~MP1~es 7 / 17/ % 6 4' .? 3(21 /oer oom@mn~rn@ ~PR I 3 '/IJ\19 ~.c. o.o.e.s. Date Ln:u & ASSOCKA'fES, INC. . .· I .-z_. Prpject · -, -· Sheet No.-of_ Geotechnj_c:~l 'Enginee'ring • Engineering Geology • Earth Science 19213 KENLAKE PLACE NE , KENMORE, WA 98028 PHONE: (425) 483-9134 FAX: (425) 486-2746 FL6)((t!:>i h f'A\/eM6JT Q$itJt,!p.No. __ ~ PL.Ar op f'LfASAtlT f'A-r:H ----~-,--'-----Job No ~Ao<f B By .JSL Date j/z7/o4 Ck'd by Date ~L.G:x..16.LE:, f'AVG-MGt-11 DG,;.IG)N l!i ~Se.DON EMPli'ZLCAt-ME;;f,:.{oe> IN " (4'13 A.A.Sl-lTo Giu1oe; Fcli<. Di;;,sre:qi-j at:: f'~Vt:::,M@N.1 ~'f~t)G'fv~~~? oa·~(qN fAMMGfeRs ! . . -ryp6 O~ RoAO: \Jl'<..SAi-l f<.E,.S1D{;"·N'T1AL-1 ONG L.Ar-.l!S f:';;A, DIRGC:.T{o"'1 JF.Afflc. Ot~'fR.I eufio...t: loo% o!== LoADl"1~ IN DG~l~iJ LAtJ& DGSIGtiJ PGRlo D: 2-o Yvs .. ANt-J<J1.>.L-&!Rou.:rri-1 RA:f~: .2 ro t,or,l~:fROl-"f1ot-l MAfe:;R(A.L.: t~'r'" HM/:>...· ~vRPAc.1::;. c:ou·I<'.~~ :_ 3 11 > .;.-11 rl MA (;ASG CoU~E; : 2." C]_ CRe:. : <a'' 0uMjRA~ ( rre~~ "f,11 ~i"l~) . St-l .:=.. 9><-t>,44+ b)(.0,13 ;;:::.. z: '1 ~ M~-:::. lb1 ooo f'St ( SuMV\'\e.-{ 8_s .~\\) · ·. ;:::: q 1 ooc, f'$l. ( Wtvi+-M g... $f'V1V1.5) Ov6,2.p.u_ ,;GC?.,\/IC??Aibl L.l"'T"y Loss. ~ DFSl.::> Po-Pt--: f. S-3,o =-1,6 R6L-\Afsl L-11'']' : (<;;. q o '7'0 ·. Ov'/E.Mu... S-rANDARO OGJtA1ioN 1 S~::. o,e:,0 . -r RP-FYI c c:::..o cJ ~-r : . _ _ . · . . · . . . eA · . w ~r .· f'A~ses/ 4Al<..&/~-6r& '("iQ.ul,\<. (S1n1l-e Livi;+)== 2. /wk.x 2.Y. '54 :::: '2.16 7''(,.; ~IR6 1S-t-l.(:i1t-l.G-"fRv'-'k(Dc>1J\.kUV1:+) :;::. lo ~.i'.ef'(v . . ./. Mov I r-l 6t -rizv ck. ( Dc> t.1 L.k UV1 (./--) :::. 2 HaVM.c x 3 r,-,w.1/'f <:::: 'Vt~ sse.y '(,,-_ rRtJt,(<.. 1AA1 N '5. ::::. 0 _ G:SAL.s ~ '2.({;,-xo,4o-1-C10+24)xl,01:1.=. f2o/yv Pe~,4 J G-:sAL ~-=-( t+<j) ':... 1 ~ )< /2,o . ::::: CJ +o. t>2.-)Z':. I X / 7-o ::::: 2 "I I b / y v . &,<>2 /' ~.A1 use-vr1_~ == 0000 /Yv. V JJIU & ASSOClfATJES, INC. 2-"2...-Project · -. SheetNo,_· _of_._ FL6i<11bi b f'A\/E::J::16.JT (&s((at,!p.No.---'-- PLA1 of: f'LBASANT eA1l:l Geotechnical Engineering • Engineer:ng GeotOQY ~ ·Earth Science 19213 KENLAKE PLACE NE • KENMORE, WA 98028 PHONE: (425) 483-9134 FAX: (425) 486-2746 --'---c~---.--.-----Job No &>Ao"'f 6 Byj$t_. Date -;/27/o'j Ck'dby Date · b~-Ci\ve; s0i;GJ~ADG RG~ILlf~i Mt:i'.Dut..,LJ.$( GJ~tww we:5 4,t-ec,Q.) ~ ~ e-M:: :::. (e, S '7')( .Cf,oo o + 0, 'T ,>( 'f ,oo0 f k o)( I "10 o o +o,qo ~ 10,0001"1"4 ~ .~~/lo p.s~ . --'-'---- u~e A&)v6 PA!ZAMGf~-S IN 11f6 h>Ll.Ot~IN~ bQ.uAT10N ~ IDj,oevfia )-==-'?:~ x so+ "7, lbxlo5 ,o(st<.l+i)-<','2-o t . \oj ('°'f"$.1. ) -o::~,,.f(~~; + 2,$2..X lo3 10 (M~)-b.ol (SNf')t;,14 ~ouJ~(ofZ~N, ~~ St-.! :;.(,(o ~ . u · ,czy: HMA '?0~0Ac.~ Ccu~SE:.: (.~ HM A ~A,;G lou~s1::; : I" · C...R. e,. ~ 1-'' .:;~ ""-( /;~f I )o.44 f Z.)(o,\_3 :::. I• '3 b Lise fl-/12; W6w 112.JP.L Sr,J =.l,5"t) At-Jo Afl.;ovf: li)G-.t1~1') f'A~rvit:,·re~s. 111A Tl-I& P.P:::oVr:; ~6l..tJA1'11DN R Sol-VC= St-l />6lA1N 1 ~etd. ~iJ= (.lo -:=(,3b SH" JL,O 0.iG () ,k. Due;-v~{l.._'f f....1 cil-i r "(~ c::f-1 c:. C.o O \J I ' .·o Core Design, Inc. cr:@m ~DESIGN 14711 N.E.29thPlace,Suite 101 Bellevue, Washington 98007 425.885.7877 Fax425.885.7963 www.coredesigninc.com April 9, 2009 Core No. 06083 Mazen Haidar, PE Engineer II King County ODES 900 Oakesdale Avenue SW Renton, Washington 98055 oorn@rnnw~l Pleasant Path -King County ConstructaJ!!I~ Review Comments APR 1 3 2009 \_..()'7:)~'(DZQ RE: K.C. D.D.E.S. Dear Mr. Haidar: This letter is in response to the constructability review and engineering review of the Pleasant Path project. Along with this letter you will find 3 sets of revised civil plans, 3 sets of the vault structural plans, 3 copies of the pavement section calculations, 1 copy of the revised TIR, I copy of your engineering review comments along with responses, and County redlined plans. If you have questions, please don't hesitate to call me at 425-885-7877. To assist in your review, we have prepared the following italicized responses to explain how we addressed each of the constructability review comments. See attached excel spreadsheet for responses to County comments. 1. The proximity of this project to the wetland should qualify it as a highly sensitive site and require a TESC supervisor. The site drains away from the wetland and is therefore, is not a highly sensitive site. 2. The luminaire plan for the frontage will be reviewed by KCDOT, I assume. As shown, the luminaries are located on private property and would require easements. The luminaires are located within the 10' utility easement located behind the right of way. The luminaire plan has already been approved by the County. 3. The utility poles relocation will require easements, and the pole relocation cost needs to be included in the bond quantity worksheet. The cost for the utility pole and luminaire relocation has already been paid to the contractor that will be doing the work therefore, the cost does not need to be included in the 06083Ltr06 King County Constructability Review Comments ENGINEERING PLANNING · SURVEYING " 4/9/2009 Mr. Mazen Haidar page 2 bond quantity worksheet. The utility poles will be located within the 10' utility easement located behind the right of way. 4. The frontage pavement widening will prompt an overlay (including prelevel) of 148th SE ( an arterial) unless waived by the County Roads Engineer. The pavement crown and cross- slope varies along the frontage. As shown on the plans, a ridge appears at the proposed pavement joint along the frontage. The applicant should be prepared for more extensive pavement work than shown on the plans, and possibly revisions to the curb grade design, to address the anticipated requirement from KCDOT for a consistent 2% cross-slope in the overlay. This same type note is shown on the plans on sheet 5 under the title "Street Widening on 1481h Avenue SE". 5. The pavement taper from the new sidewalk at the south end of the frontage is called out incorrectly to begin at the curb rather than from the back of sidewalk. Revised as requested 6. The vault outfall along the existing ditch along 148th SE is problematic. Placing it under the ditch causes the pipe crown to daylight as much as 40 feet along the downstream end of the pipe. This renders the existing ditch ineffective and out of compliance with the Road Standards, not to mention the pipe material needs to be ductile iron for lack of cover. It is clear the minimal pipe slope is dictated by the vault outfall invert. One way to address this issue would be to add a Type I catch basin at the end of the pipe, revise the ditch to a paved shoulder section with extruded curb along the length of the pipe, then provide a pipe stubout outfall from the added catch basin. Unfortunately, this would likely prompt an extension of the pavement overlay requirement along 148th SE due to the added paved shoulder. Another way would be to do the same installation but offset the pipe alignment from the ditch, the provide the stubout at an angle to the ditch, and maintain/restore the ditch to its current configuration. Please note there are existing drainage problems immediately to the south along 148th SE due to the Jack of an existing pavement crown. Whatever solution is designed, it must not exacerbate the existing drainage issues downstream. The vault outfall has been revised per conversations with you (Mazen). 7. The outfall pipe in the 148th SE ditch requires a beveled end. Callout added 8. The steep pipe between CB3 and Inlet 3A creates problems where the pipe connects to the CB and the vault. A large elliptical opening in both is required to allow the pipe penetration. The Type I CB 3 may not have enough wall to accommodate the opening. The vault opening structural reinforcement requires specific attention. An alternative would be to move CB3 to the north, allowing a reduced pipe slope. There is plenty of room in the landscape tract to do this. A public drainage easement over the tract is 06083Ltr06 King County Constructability Review Comments , 4/9/2009 Mr. Mazen Haidar page 3 already required to allow vault maintenance, so this easement would cover the conveyance at any location within the tract. CB 3 has been relocated to provide a reduced pipe slope. 9. In the vault, the circular sump for the restrictor T creates a few issues. The sump is usually provided by the use of a Type II catch basin sump. This sump location typically conflicts with the vault footing. It also sets the T back from the vault wall, requiring additional bracing of the T in the gap. This is apparent in the Restrictor Plan View detail (in conflict with the Restrictor Detail elevation view). Also apparent in that detail is the conflict wiith the required 2-foot clearance for the personnel access. The use of the Type II sump is suitable as long as these issues are addressed. Per conversations with the structural designer of the vault, the sump poses no problem as currently shown. During construction, the sump will be placed prior to the pouring of the vault footing. The vault footing will be cast against the sump as indicated on the structural plans. A note to this same effect has been added to the Vault Section B-B on sheet 8 .. I 0. I suggest the street tree plan will only require four trees at the frontage, rather than the crowded six shown on the plan. Six trees along the frontage are required to provide minimum number of trees required by Code. Sincerely, CORE DESIGN, INC. '6\N-.,~\b Gina R. Brooks, P .E. Project Engineer grb@coredesigninc.com 06083Ltr06 King County Constructability Review Comments r; ILIUISD ENGINEERING REVIEW SECTION S1"1RUCTUIRAl REVIEW TRANSMITTAL TO: Hou-Ching Chow, P.E., S.E. *FM: Mazen Haidar, P.E. * DATE: February 10, 2009 *RE: SW Detention Vault for Plat of *Project# L98SR020 (project) Please accept and review the attached Structural Review Package. The LUSD Engineering Review Section has begun reviewing the engineering plans for the road and storm system; we anticipate completion by as soon as possible. Your efforts in assisting us with this deadline are greatly appreciated. Please contact me at 6-7133 when your review begins or at any time you require additional information. Upon structural approval, please return the plans and approval documentation to the LUSD Engineering Review Section with an approval memole-mail and stating any additional required fees. * Description of Structure: Two-cell reinforced concrete underground vault *Location of Structure (Page# and/or describe location): Section 202605 Corner of Assessors Parcel# 1123059010 (148th Ave, SE) Future Public ROW: Existing ______ _ ------- Future Public Tracts: Existing ______ _ ------- Future Private Tracts: Existing ______ _ ------- Future Easement(,-----,,,..--,--·): Existing ______ _ ------- (Type) Restrictions/Requirements Related to the Structure: (e.g. other approvals (HPA, DOT), ordinances, elevations) *submittal Package Includes: Engineering Plans (RoadiDrainage) Structural Drawings and Plans Manufacturing Specifications (if necessary) Design Calculations Soils Report minimum: 1X13 Sheetscopies (1) 2 x 3 Sheets copies (2) copies (2) 2 Report copies (2) copies (1) Note: If this is a REVISION to an approved structural plan, then include the approved plans. List of Key Contacts: · King County Sensitive Area Staff: Design Engineer: Structural Engineering Plans: Other: ----------------------------- 1 n st a i I at ion /Inspection Inspection Responsibility of Commercials: ________________ _ Contractor License # (if needed) _______ _ Structural Value $ ------ Attachments *REQUIRED ----------------------------- REVISION DATE: ------,.,,.----....,....,,.../'\ ....... ~----- SIGNATURE: __ ___,L,_~"'!:;g~.~· ~;,----=~-------- .•• ti King County Department of Development and Environmental Services Land Use Services Division 900 Oakesdale Avenue Southwest Renton, WA 98057-5212 206-296-6600 TIY 206-296-7217 www.kingcounty.gov January 8, 2009 Josh Beard, LA Core Design 14711 Northeast 29th Pl, Suite 101 Bellevue WA 98007 RE: Pleasant Path Short Plat {ODES File No. L07S0018) Recreation Space Plan Activity No. L08MI075 Dear Mr. Beard: ' draft This is in response to your December 31, 2008 request for approval of the landscape and recreation space plan for the Pleasant Path short plat. We have reviewed your submittal, and with the following conditions and additions, approve it as submitted: 1. The equipment (structures, benches, picnic table, etc.) shall meet at a minimum, Consumer Product Safety Standards and be appropriately anchored. 2. Walkways/Trails shall be installed from the sidewalk to the play areas. Walkways shall be constructed of a material and grade that is Americans with Disabilities Act (ADA) accessible. 3. The fence along the perimeter of the tract shall be backed by either chain link or low plantings to alleviate any potential conflicts between users of the recreation space and vehicles (i.e. balls rolling into street, etc.). 4. The grass-crete or other alternatives for access to the stormwater facility must be approved with the engineering plans. If this surface is not approved, a revised recreation plan will be required. In the event a solid surface (i.e. asphalt, concrete, or similar) is required for the drainage facility a revised plat layout may be required, as the access to the drainage facility and associated appurtenances are not counted toward the recreation space requirement. 5. In the event the engineering plans, soil amendment, street tree and/or significant tree plans result in modification/revisions to the recreation space plan, a revised recreation plan will be required. The landscaping and recreation space improvements (i.e. play structures) must be installed and inspected or a performance bond posted, prior to plat recording. The amount of the bond has been established at $40,000. This includes landscaping, equipment, surfacing materials, fencing, etc. The bond amount includes a thirty- percent contingency, as well as the requirement for the wood fence to be backed with chain link or additional shrubbery/low plantings along the fence. Note, this approval does not include soil amendment plan, street trees or significant trees. This will be reviewed in conjunction with the engineering plans. An inspection fee is also due prior to recording. This fee covers the cost of an installation inspection and a maintenance inspection. The amount of the inspection deposit will be determined by the Land Use Inspection Section (LUIS). If a performance financial guarantee is posted, the improvements must be installed within two year's from the date of recording. At the time of inspection by the Land Use Inspection Section, if the improvements are fully installed per the approved plan, the performance financial guarantee may be reduced. Enclosed is a copy of the approved plans for your records. If you have any questions, please call me at (206) 296-7167. If you have questions regarding the financial guarantee please contact Carol Rogers, Finance Section at (206) 296-7250. Questions regarding the inspection process may be directed to the Land Use Inspection Section (206) 296-6642. Sincerely, Kim Claussen, PPM Ill Current Planning Section Cc: Pete Dye, Engineering Review Section w/enc Ray Floren!, Engineering Review Section w/enc Steve Townsend, Development Inspection Section w/enc FGMU w/bond quantity worksheet File w/enc .. ~ Core Design, Inc. ~0/!R?.IE ~DESIGN 14711 N.E.29thP/oce,Suite 101 Bellevue, Washington 98007 425.885.7877 Fox425.885.7963 www.coredesigninc.com December 8, 2008 Core No. 06083 Ms. Kim Claussen Land Use Services Division Department of Development and Environmental Sewices King County 900 Oakesdale Avenue SW Renton, WA. 98055-1219 Re: Pleasant path Subdivision-On-site Recreational Facilities Narrative (10750018) Dear Kim: Please find the following narrative to help explain the Bond Quantity Work sheets for the Recreation Space & Landscape Plan. ' Recreation/Landscape Plan: Cut Sheets- A) Cut sheets have been provided for the proposed play equipment (Highlander I by Gorilla Playsets) and safety surfacing (Sof'Fall by Sof'Solutions) and furnishings (bench, table, trash receptacle by Fairweather). Landscape Bond Quantity Worksheet A) A landscape bond quantity worksheet has been provided to include improvements within the recreational space tract.. Under the "Additional Items" section the price shown includes the play structure ( +/-$3,700), safety surface installation (+/-$1,000), 1 bench & 1 table (+/-$800), 1 trash receptacle(+/-$300), rail fence ( +/-$2,900), timber edge ( +/-$500) and gravel path (+/-$1,170). Please contact me if you have any questions with your continued review. ~~CC~u~~lQ) DEC '.11 2008 JoshB , LA. Landscape Architect LO 800 JI 015 ENGINEER/NG PLANN/t¥ce, Q;\;)P;~·YING I . -~ ® King County Department of Development and Environmental Services 900 Oakesdale Avenue Southwest Renton, Washington 98055-1219 206-296-6600 TTY 206-296-7217 PROJECT NAME: Pleasant Path (Rec. Space) Web date: 11/16/2005 LANDSCAPE BOND QUANTITY WORKSHEET·FORM . For alternate formats, call 206-296-6600. DOES PROJECT#: ---'L=0'-'-7=-50""0c.c.1=-8 __________ _ ADDRESS: PREPARED BY: _C=-o=--cr-=-e--=D--=e.:::si""-gn"''-'-1 n"'c"-. --"( J--=o=-sh-'-_ =-Be.cca=.r.:cd ,c.:.R..:.:LA=-_ "-)-PHONE: 425. 885. 7877 Bonds are based upon required landscaping only and will be posted for performance and/or maintenance. Required landscaping includes perimeter landscaping, surface parking area landscaping, (KCC 21A.16) and any landscaping required by SEPA environmental review. The maintenance period is for the life of the project, however, after posting for maintenance, the performance bond will be reduced to 30% ($1,000.00 minimum) and be held for a two year period. Upon re-inspection of the site the bond will be released if the site has been properly maintained (21A.16.180). A landscape maintenance inspection deposit is required prior to pennit issuance to cover the costs of the 2-year maintenance inspection. Landscape inspections are billed at the current hourly rate once the initial deposit is exhausted. If the project has not been maintained and there are dead trees, shrubs, ground cover, or other deficiencies noted in the required landscaping, the bond will be held until the deficiencies are corrected. · UNIT PRICE· UNIT TYPE QUANTITY PRICE SOD LAWN AREAS $500.00 MSF (1000 SQ. FT) -- HYDROSEEDING $50.00 MSF (1000 SQ. FT) 4.3 215 --. ··-. ,.".:.. , .. , -. '-··----, .,, . ~::.. -·-··· -4 ---.;:-. ;· .. ~ . - SOIL PREPARATION A. TOPSOIL (6 INCHES DEEP) $25.00 CY (CUBIC YARD) 110 2,750 B. MULCH (2 INCHES DEEP) . $4.00 SY (SQUARE YARD) 318 1,272 C. PEAT MOSS (fWO INCHES DEEP) $2.30 . SY (SQUARE YARD) D. COMPOST (3 INCHES DEEP & TILLING $26.00 SY (SQUARE YARD) E. FERTILIZER $6.67 CY (CUBIC YARD) 1 6.67 -. -· -., . PLANT MATERIALS A. DECIDUOUS TREES 1.75-2.00" CALIPER (minimum height 10') $250.00 EACH COST & LABOR PERIMETER & PARKING AREAS 5 1,250 1.5 -1.75" CALIPER $225.00 EACH COST&LABOR IITTERIOR LANDSCAPING OR OTHER REQUIRED LANDSCAPING B. EVERGREEN TREES FIVE (5) FEET OR ABOVE $150.00 EACH COST & LABOR 4 600 C.SHRUBS $35.00 EACH COST& LABOR 80 2,800 D. GROUND COVER $4.00 EACH COST & LABOR 870 3,480 SUB TOTAL BOND AMOUNT BOND AMOUNT SUB TOTAL: $ 12.373.67 06083 LandscapeBondQuantity recspace.doc b-wks-landscapebq.pdf 11/16/2005 . I UNIT PRICE UNIT TYPE QUANTITY PRICE • ,~ 0 ' ,.,,.. ,, ·, ._ .... ,, 'd.(;:',":.=,_ ,; ,_. .,,.,.,,,,.,: ..lc!>~ '' ' ' ' ' ---;,~r.:. _ -''.'·.·t· ~ '"'.!"' '. . ;.,;:-"•,1,.:,~ ... ' ;.;;,;;, -·:.~· MISCELLANEOUS TREE STAKES $2.65 EACH PER STAKE & LABOR 27 71.55 FENCING: LINEAR FOOT SOLID WOOD CEDAR $28.50 INCLUDES LABOR -- BERMING $17.50 LINEAR FOOT INCLUDES LABOR IRRIGATION 80¢ SQUARE FOOT 7,290 5,832 RELOCATING TREES ON SITE 36" BALL $260.00 EACH 60" BALL $920.00 EACH RELOCATING SHRUBS ON SITE 12" BALL $26.00 EACH 24" BALL $33.00 EACH ADDITIONAL ITEMS: Onsite recreation facilities ' 1 $10,370 SUB TOTAL BOND AMOUNT BOND SUB TOTAL: $ 28,647.22 Add 30% of the Bond Sub-Total for Contingency in accordance 30% CONTINGENCY: with Financial Guarantee Ordinance 120220, Section 13. $ 8,594.17 TOTAL BOND PRICE TOTAL BOND PRICE: $ 37,241.39 Revised LBQW 11/13/2002 Check out the DDES Web site at www.metrokc.gov/ddes 06083 LandscapeBondQuantity recspace.doc b-wks-landscapebq.pdf 11/16/2005 faircWeather Standar,d Recycled Plastic SeOection .,_ ,- Gr~JI Weathered Wood lfairWeathei: Standard (olor, Selection IF0a1l: or GOoss or Semi- Gioss IBOack fOJ~(C~~~lE~ lfil DEC ~ 1 2006 K.C. D.D.E.S. 12 I I I I ··., . •. . . 3/411 .. L ·v ' .·•. . . . • • • L... ,'.· . . . EMBED 12" LESS THAN OUT TO OUT DIM. .120 x 2" x 2" STEEL TUBE '-1/2" HOLE FOR #3 REBAR PLEASE NOTE, DEPlH AND DIAMETER OF INSTALLATION HOLE MAY VARY WITH SOIL CONDITIONS. CONSULT PROJECT ENGINEER FOR CORRECT DIMENSIONS . ~ 2"x3" WOOD (11/2" X 2 1/2") ' 6" t I SURFACE MOUNT r-1/2" SPACE (typ) 3/B" x 3" STEEL STRAP_/ ~ :\ ~ . . 15"_J 161/2" 5/B" DIA. HOLES FOR 1/2" ANCHOR BOLTS. (ANCHOR BOLTS &Y OTHERS) I 2911 -r + 161/2" 3/8"x3 1Lairndlscape §eiries, Modi.ell JL-2 lBeirnch. STEEL STRAP REV. 6--JO--Oj 5PECIFICATION5 MATERIAL Wood: Wood shall be 11 ea. 1-1/2" x 2-1/2" boards, all edges eased. All boards are 2 inches shorter than nominal size. For example, 6 ft. bench would be 5 ft. 10 in. out to out. Frame: The frame shall be fabricated 3/8" x 3" mild steel drilled and formed for quick assembly, fully welded to .120 x 2" x 2" square steel tube. Benches 5 ft. through 7 ft. long shall.have a center strap. Benches 8 ft. through 12 ft. long shall have a complete center frame. All steel shall conform to ASTM A 36 hot rolled steel. FASTENERS Wood shall be attached to frames with vandal resistant stainless steel pan head screws. Mounting hardware by others . PROTECTIVE COATINGS Wood: clear wood preservative Metal: All metal elements, following fabrication shall be cleaned and treated with an iron phosphate process prior to the coating application. This process shall include a non-chromated alkaline cleaner, and an iron phosphate treatment followed with an acidic sealer for maximum adhesion. The protective coatings shall be either polyester or polyester TGIC powder. Following application the parts shall be baked until properly cured. The coating shall be a minimum of 4 mils thick on all surfaces. OPTIONS Mountings: Surface mount or embed Arms: Arms shall be 3/8" x 2" steel strap welded to seat. Length: 4 to 8 ft. standard, other lengths available Wood: Western red cedar, clear vg Douglas Fir, lpe other species available on request . Recycled Plastic: Grey, cedar, weathered wood, light oak FairWeather Site Furnishings 360-895-2626 or Toll Free 800-323-1798 Port Orchard, Washington Cl 1999-2004 Leader lniemarional Corporation, Fair Weather Site Furnish.in gs division ,,,.. V r L • • . . . • ~~~ 3" x rx.120WALL TUBE 3/16"x3flxr ANGLE • • - - • . , . , • • . . • • • . . . • . • . . . . . . • • R RECYCLED PLASTIC . • . I . • • . . . . . . 1 I I I I "Lt I I I I I I " 7 " / ,. • '-_GRADE :. < 1 ....... • ·: .. ·-=-:~·· . . - EMBED MOUNT 3/8" x 16" x 16" BASE ,-14"J Sfl x snx.180WALL TUBE 5/8" HOLES FOR tn• ANCHORS SURFACE MOUNT Mocllell JF-4l or JF-4llP' 48" Picnic 'fable with Wlbteellclbtaiir Access, 4l x 4l Sllats I I I I '-/ REV 11-02-06 SPECIFICATIONS MATERIAL Table & Seat Tops: 3-1/2" x 3-1/2" wood or · recycled plastic, nominal size is 4 x 4. Frames: 5" x 5" x .180 steel tube center post. Table top and seat frames fabricated with 3" x 3" x .120 wall tube, 2" x 3" x .120 wall tube and 3" x 3" x 3/16" angle. Steel shall conform to ASTM A36 hot rolled steel. All angle and flat stock shall be wheelabrated prior to fabrication. HARDWARE Slats shall be attached to frames with 3/8" plated carriage bolts, nuts and washers. Assembly hardware is provided. Seat arms shall be attached to center post with carriage bolts secured Inside center post for cleaner appearance and Increased vandal resistance PROTECTIVE COATINGS Wood: clear wood preservative Recycled Plastic: none Metal: following fabrication frames shall be cleaned and treated with an iron phosphate process prior to the coating application. The protective coatings shall be either polyester or polyester TGIC powder applied by the dry electrostatic method. The coating shall be a minimum of 4 mils thick on all s·urfaces. Option: Hot dip galvanizing for frames, in place of powder coating OPTIONS surface or embed mount Lag bolts for assembly hardware Table & Seat Tops: F-4 Wood: Western Red Cedar, clear vg Douglas Fir, lpe F-4P Recycled Plastic: Gray, weathered wood, cedar Embed mounting: Depth & diameter of post hole may vary with soil conditions. Consult project engineer for correct dimensions. Surface mount: Anchor bolts by others FairWeather Site Furnishings 360-895-2626 or Toll Free 800-323-1798 Port Orchard, Washington 01999-2006 Leader lntemation.al Cmporation, FairWcathc:r Site Furnishings division 51/2" I - 0 0 0 0 0 ---. ' 0 0 'o 0 O' ~ ' \ JJ ~A/ TR-2 WITH OPTIONAL BOLT DOWN PEDESTAL 0 0 0 0 0 0 0 0 0 0 0 ·. .. . (18) 1 1/2" x 3 1/2" ELEMENTS ./ 0 0 0 0 /$12"""'-',, ,' HOLES ', < ;:3 .• <•=> \, ·········-a····/·· ~r~r ~,;'--:CE""' : --:-T / \ 2"106""511!EQU!JtEI): ', . . _l ,' -~A~ 0 C 29 0 l L , . TO 4" AS REQUIRED +. ,_ . . : : ""' . t • 2"5CH 40 F 0 • (20" LONG) '--;J .,.· . a , .. •. TR-2 TAPERED WITH OPTIONAL PERMANENT EMBED PEDE5TAL PE 27" 21 1/2" -1/"1-R b I t:t.L HUUl"t> (2 PLACES) 0 0 0 0 0 0 0 -r 29" 0 0 0 0 0 0 .[J - 11/4" TR-2 WITH STANDARD SURFACE MOUNT REV. 8-10--06 'JI'R-2 §tiraiglhit alJJl.dl 'JI'R-2 Tapered! Tiraslht JReceptacile 5PECIFICATION5 MAiERIAL The TR-2 receptacle shall be fabricated with · 18 each, 1-1/2" x 3-1/2" wood elements. Elements shall be fastened to 1/4" x 2" and 1/4" x 3" mild steel hoops. Hoops shall be powdercoated a standard FairWeather color. All steel shall conform to ASTM A 36 hot rolled steel. Liner shall be standard 30 gallon galvanized can. FASiENERS Wood shall be attached to hoops with carriage bolts unless otherwise specified. Surface mount: Anchor bolts by others. PROiECTIVE COATINGS Wood: clear wood preservative Metal: Following fabrication, all metal elements shall be cleaned and treated with a five stage iron phosphate process prior to the coating application. The protective coating shall be either polyester or polyester TGIC powder applied by the dry electrostatic method. ,he resultant coating shall be minimum of 4 mils thick on all surfaces. OPTIONS Straight or tapered sides Leveling feet (set of 4) Wood: Douglas Fir, Red cedar, lpe Recycled Plastic: Grey, cedar, weathered wood Mountings: Surface, embed or pedestal base Tops: Spun steel flat top, spun steel dome top, galvanized dome top Hardware: Lag bolts, corrosion resistant undercoat (frames) Please Note: For Embed Mountings Depth and diameter of installation hole may vary with soil conditions. Consult project engineer for correct dimensions. FairWeather Site Furnishings 360-895-2626 or Toll Free 800-323-1798 Port Orchard, Washington Cl 1999-2005 Leader International Cmpora1lon, FairWeathei-Site Fumishing5 division ~oPFall Eog;o=d Wood Fibcr is , sfrgio wood ,~faciog d.ai is oooSoric, ooofl-,bL. P,8" 1 of2 Specifications DESCRIPTION OF PRODUCT • Product is manufactured engineered wood fiber fiber comprised of softwoods and/or hardwoods, consisting of randomly sized wood fibers the majority of which do not exceed 1.5" in length and containing 10% to 20% fines to aid in compaction. (It is generally understood that the manufacturing process allows a few oversized pieces.) • Product must prove to be non-toxic. It may not contain any recycled wood products or any wood containing paint, chemicals or additives. Bidder to provide Toxicity Test Data*. • Product to have minimal bark and to be free of twigs, leaf debris and other organi material, and to be certified as non-flammable. (Test data available upon request • Product depth, after installation, must be in accordance with the procedure described in ASTM F-1292 and meet guidelines for critical height as set forth by the CPSC for use of wood products for protective surfacing. Click below to see CAD details of our products. ~··: CADdetails.com ~ --?ROOUCT S?EC~SHEETS ASTM TESTING CERTIFICATION . Manufacturer must be in compliance and provide testing data for the following standards as set forth by the American Standard for Testing Materials (ASTM), for surface systems under and around playground equipment. 1. ASTM F-1951-99 (Previously ASTM PS 83-97) Determination of Accessibility of surface systems under and around playground equipment* 2. ASTM F-1292-96 IMPACT ATTENUATION of Surface Systems Under and Around Playground Equipment* fa l's r-' ,. 3. ASTM F-2075 Standard Specification for Engineered W~ ~~f~UJ,83 LG ID) lL {!) 8 00 JI O 15 OEC :l 1 2008 htto://www.sof-fall.com/soecs.aso K.C. D.D.~9/06 ,,. SofFall Eogm~ced Wood Fibcr is , C,~o wood s,rrfaoiag '"" is ooo<oai,, ooofl-abL Pago 2 ol 2 as a playground safety surface under and around playground equipment. CSA -Meets or Exceeds Canadian Standards Association (CSA) 2614-98 IPEMA Certified Manufacturer must provide proof of certification. "In the interest of public playground safety, IPEMA provides an independent laboratory which validates a manufacturer's certification of conformance to ASTM F-1292-99. A list of current validated products, their thickness and critical height may be viewed at WWW.IPEMA.COM" GEOTEXTILE WEED BARRIER FABRIC • Installation of Geotextile fabric must accompany SofFall Engineered Wood Fiber on all new installations. • Geotextile fabric must be a minimum of 28 mills thick and have a tested 26 gallon per square foot per minute permeability. Download an Installation Spec Sheet MANUFACTURER AGREEMENT • Manufacturer must carry 10 Million Dollars in Product Liability Insurance • Manufacturer must have a written 10-year limited product warranty. *If a summary of these items does not accompany this specification please contact yo1 representative or customer service Welcome to SofFall®; SofFall® Is, Specifications I Delivery & Installation Maintenance I Rep Login 1SofMat™ 1 Industry Standard I Request Information I Home Copyright .WOO -2005 Sol'So!utiun~rM lncorpor.'.lted -All rights rcSL'J"Vell. http://www.sof-fall.com/specs.asp 8/29/06 [}{] D@JD'u0©1[n)@J@IT1 1J ~ ~ &~~@mm[b)01f !R§il~[fi)M~O _ • Copyright© 2007 Gorilla Playsef@) ~ ~ ~ ~ W ~ D' , All Rights Reserved [ru l.!:V . ~de in the U.S.A. DEC 31 2008 IL OriS1iuLlCD9'Z1uh Industrial Court• Canton, GA 30114 • caoroQ38:0cflifi,S. . IMPORTANT INFORMATION~ IF YOU HAVE MISSING OR DAMAGED PARTS OR. NEED ASSISTANCE ASSEMBLING, PLEASE CALL gorilla playsets@ MANUFACTURING DIRECT. (800) 882m0272 f ACTORY HOURS -MON.-FRI., 8AM-5PM EST DO NOT RETURN THIS PRODUCT TO THE RETAILER OR CONTACT THE RETAILER DIRECT. THE RETAILER DOES NOT STOCK COMPONENTS. CONT ACT INFO: Gorilla Playsets, Inc. 190 Etowah industrial Court Canton, GA 30114 Tel. (678) 880-3328 Fax. (678) 880-3329 custsrv@gorillaplaysets.com 2 Thank you for choosing gorilla playsets® for your new backyard playground! We've included everything you need except tools, to build your very own professional looking playset. When complete, your new playset should far exceed the quality of playset kits from other build-your-own companies. Our engineers and design team have over 30 years of playground experience. What we've developed is a playset that doesn't compromise quality for simplicity. Yet you11 appreciate how quick and easy construction really is! Our playset kits are designed for children ages 3 to 11. gorilla playsets® believes every child should have a playset and with our kits they can! You can rest assured your new playset is safe, durable and designed to hold up to the elements. As parents ourselves we know how important the · security and well being of our children is and this shows in all of our products. Each playset features our step-by-step 3D illustrated manual, patented powder coated swing beam bracket, heavy-duty swing belts with chains, slide(s), accessories, plus all the required hardware and pre-milled lumber. Quality Lumber At Gorilla Playsets, we use only the finest, hand selected lumber available. Whether you choose a playset made from our Premium Preserved Pine, our Beautiful California Redwood or our Western Red Cedar, you can be assured that our lumber is strong, durable, and conforms to the national standards for use in children's play equipment. It's this quality that allows us to offer a 10 year warranty on the lumber used in our play sets. Premium Preserved Pine Our Premium Preserved Pine is double kiln dried. We utilize this process to minimize shrinkage, warping, and cupping. Because our pine has been "pre-shrunk", the hardware used to assemble your playset will hold tight, stay tight, and won't loosen or weaken. Our preserved pine is clean, odorless, non-staining, and non-irritating to humans, animals, or plants. Gorilla's Preserved Pine uses one of the only exterior wood preservation systems that is EPA approved. Our pine lumber is preserved with a preservative system containing copper and quaternary compounds to protect against termite attack and fungal decay. Our Premium Preserved Pine can withstand harsh weather conditions and is effective for decades, Making Gorilla Playsets the best choice in pine lumber built swing sets. 4 limited Manufacturers Warranty gorilla playsets® ("Gorilla") warrants this product to be free from defects in workmanship and materials, under normal use and conditions, for a period of 10 years for structural wood components and one year for all other components (i.e., hardware, plastics, tarps, rope ladder, etc.). Cosmetic defects that do not affect the structural integrity of the product, or natural defects of wood such as warping, checking or any other physical properties of wood · that do not present a safety hazard, are not covered by this warranty. gorilla playsets® will repair or, at its discretion, replace any part within the stated warranty period that is defective in workmanship or materials. This decision is subject to verification of the defect upon delivery of the defective part to gorilla playsets® at 190 Etowah Industrial Court, Canton, Georgia 30114. Any part(s) returned to gorilla playsets® must include proof and date of purchase. This warranty is valid only if the product is used for the purpose for which it was designed and installed at a residential, single-family dwelling. This warranty is void if the product is put to commercial or institutional use. This warranty does not cover (a) products which have been damaged by negligence, natural disasters, or accident by improper use, or which have been modified or repaired by unauthorized persons, (b) the cost of labor, or (c) the cost of shipping the product, any part, or any replacement product or part. This warranty is valid only in the United States of America, is non-transferable and does not extend to the owners of the product subsequent to the original purchaser. gorilla playsets® disclaims all other representations and warranties of any kind, express, implied, statutory or otherwise, including the implied warranties of merchantability and fitness for a particular purpose. gorilla playsets® will not be liable for any incidental or consequential damages. Some states do not allow limitations on implied warranties or exclusion of incidental or consequential damages, so these restrictions may not be applicable to you. This warranty gives you specific legal rights. You may also have other rights that vary from state to state. IMPORTANT SAFETY GUIDELINES This product is intended for residential use only and not intended for use in any public setting. A safety surface such as mulch or recycled tire should be used under the play set to prevent injury from falls. Also a 6 foot safety zone should be used around the entire playset. As with any home project, good judgment and respect for power tools will greatly reduce the risk of injury. gorilla playsets® recommends you follow all tool manufacturers' safety guidelines. Always wear eye protection and safety gloves to prevent injury. In several phases of construction two people may be required for lifting and securing of lumber. While playset is being constructed, please keep children off the equipment until the project is complete. Bolts and screw heads should be checked regularly for tightness. The ground ladder, rope ladder, slide, swings and other areas where children spend a majority of their playtime should be checked more frequently. gorilla playsets® shall not be liable for incidental, indirect or consequential damages or injuries that result from the building and/or playing on our playsets. Adult supervision is recommended anytime a playset is being used. 5 WEIGHT liMITS FOR GORILLA PLAYSETS o FORT PLATFORMS: 800 LBS. TOTAL WEIGHT o SWING BELTS: 175 LBS. o GLIDER SWINGS: 70 LBS. PER CHILD o TRAPEZE: 125 LBS. o FULL BUCKET SWING: 50 LBS. o TODDLER BUCKET SWING: 50 LBS. o INFANT SWING: 35 LBS. o TIRE SWING: 125 LBS. TOTAL WEIGHT o ROPE LADDER: 75 LBS. o ROCK WALL: 150 LBS. o ALL SLIDES: 250 LBS. Gorilla Playsets recommends that the weight limits for all components must not to be exceeded. Failure to adhere to these and other safety guidelines could result in damage to the playset and injury to the users. 6 Safety and Maintenance Tips for Your New Play Set: o It is recommended that on site adult supervision for children of all ages be present while playground equipment is in use. o Please restrict children from walking close to, in front of, behind or between moving items. o Restrict children from twisting swing chains or ropes since this may reduce the strength of these items. o Warn children to avoid swinging empty seats. o Teach children to sit with their full weight on the center of the swing seat. o Teach children to use the playground equipment in the intended manner. o Teach children not to get off play equipment while still in motion. o Parents should make sure children are dressed appropriately. For example: wear well fitting clothing, shoes, avoid ponchos, and scarves or any loose fitting clothing, which may be potentially hazardous while using the playground equipment. o Restrict children from climbing on playground equipment when wet. o Check all nuts and bolts twice monthly during the usage season for tightness. Tighten as required. It is particularly important to check & tighten bolts at the beginning of each season. o Check swings, chains, and slides for cracks or deterioration. Replacement should be made at first sign of deterioration. Playgrounds should be inspected on a regular basis. If any of the following conditions are noted, they should be removed, corrected or repaired immediately to prevent injuries: (see list, following page) o Hardware that is loose, worn or that has protrusions or projections o Exposed equipment footings o Scattered debris, litter, rocks, or tree roots o Rust and chipped paint on metal components o Splinters, large crack, and decayed wood components. o Deterioration and corrosion on structural components, which connect to the ground o Missing or damaged equipment components, such as handholds, guardrails, swing seats 7 l?lay Set Surfacing Recommendations: Below are some of the recommendations that the U.S. Consumer Product Safety Commission (CPSC) offers from its Handbook for Public Playground Safety. 1. Protective Surfacing -Since almost 60% of all injuries are caused by falls to the ground, protective surfacing under and around all playground equipment is the most critical safety factor on playgrounds. Certain manufactured synthetic surfaces also are acceptable; however, test data on shock absorbing performance should be requested from the manufacturer. Asphalt and concrete are unacceptable. They do not have any shock absorbing properties. Similarly, grass and turf should not be used. Their ability to absorb shock during a fall can be reduced considerably through wear and environmental conditions. Certain loose-fill surfacing materials are acceptable. Surfacing materials are acceptable, such as the types and depths shown in the table. ~~~~~~~.~···! li¥'iie of mateilial> .. ,::, ·. · ;: JI 6WDeethW ,,9!:' P,erillL]I 1~~~ioei:illi] !Q_g4blfJ.,!:liJ.~f!£fCifJ.cJ_:9f![.'5.JpUlq/:L,,.···1J1:_,:, __ .6~ c,:.,,:I_:_:_, 10' .. •-.. JI· _, .... J!! · .. ~. IWciodchips •.. •. . . : .:::_:JI ···e:· : ·11 ' 7' ii ' 12'. : •,: ' IIFl·n· .. e·s···a·n'.-:-d-·-;::.;: .. ,.,., .~·-. --·> , ... ,. "'I=-''·'"' 5· '·, · ·•1·· 1' ••1·'5• , ' ·'I'' · · ·g•: · ·• · . . . ~: .. ' :_:j' . . ' . · .. · . . . . . . '.'~ ' ' ' ... , Jlf:'inif''grave/ .·: · ···:0 ·······" . ··''>~·· ·-. .:-· ,·1!:,: '---~~·:~[,,·,:-_7':,_::,•'. :,!,".Jlc •·'~:.:Jc,J0',1 · ... ,d n~· .;.:~;:i,.,, · ,. . t:~.: ~:;(~:.~~:..~--~~~ ·;~~~~:~.~~·~JI]:: .. :,,:;.~:~.'.'.~·~:::~ :~.~~.1~J I:-.. .. ~·;.·~~~:~.: .. ::~~~;;;~:,!~~: .. : 1 · .. ::.~:~:ii.:a,~, .. .: .... ::~~~~ ;:,11 .. :: .. "·. · ';-~;.;,:.~ ... J,;: __ .:f'.~~ It should be recognized that all injuries due to falls cannot be prevented no matter what surfacing material is used. 2. Fall Zones -A fall zone, covered with a protective surfacing material, is essential under and around equipment where a child might fall.This area should be free of other equipment and obstacles onto which a child might fall. Stationary climbing equipment and slides should have a fall zone extending a Minimum of 6' in all directions from the perimeter of the . equipment. Swings should have a fall zone extending a minimum of 6' from the outer edge of the support structure on each side. The fall zone in front and back of the swing should extend out a minimum distance of twice the height of the swing as measured from the ground to the top of the swing support structure. 8 " -,.;. -t.-~J [7) I -.. .. , ® King County Department of Development and Environmental Services Land Use Services Division 900 Oakesdale Avenue Southwest Renton, Washington 98055-1219 (206) 296-6600 TTY (206) 296-7217 Alternative formats available . upon request Drop-Off Cover Sheet for Land Use Services Division **************************** IMPORTANT*************•••••••••••••••• PROJECT NUMBER AND NAME IS NECESSARY FOR ALL ~~OP-OFFS Project No.: L D7'5()()/ 8' Project Name: Pl~ ?C{~ r fctti-.. FROM: · uJvf._ Pe.'.>'~h / R.Jh 0f't,111.1<,,, 6-,1--i1 £yp)t:s Company Na e /Contact Person ' Telephone No.: 4-ZS: {11,,-?«77 To: JLi:Z.PI'.\ tf,,,.'dor Date Received by LUSD ADDITIONAL INFORMATION REQUESTED BY KING COUNTY STAFF (please print) Short Plat/ Plats Please specify item(s) dropped-off: Lot Line Ad!ustment Permit ." Please specify item(s) dropped-off: Right.of Way Permit Please specify item(s) dropped-off: Clearing / Grading Permit · Additional Information requested; please specify item(s) dropped-off: v-s 'l(i,, ' "' (") Ill' 0 m <fl KS = '° '-» CI:: N -.I ;r., :r :,:, a, ,v Lti t"} r-·, ' ' .. ~c r - '.:.; I Other:------------------------------------ PLEASE NOTE: All drop-off item(s) will be logged into the computer under the project number, therefore, it is important that the top portion of this form is completed properly before you· drop-off anything. Assistance In finding a project number can be provided by speaking to a Land Use Services Division Person of the Day (POD) or the Zoning/Land Use Technician. Your cooperation is important. Thank you. LUSD Drop-Off Cover Sheel lg-cvs-<lropoff.pdf 05-30-2002 Page 1 of 1 ti! King Coo.nm:y Department of Development and Environmental Services 900 Oakesdale Avenue SW Renton, WA 98055-1219 ' Engineering Review Comments Review Date: 02/25/2009 Reviewer Name: Mazen Haidar, P.E. Project Type : 8 Lots Short Plat Project Name : Pleasant Path Short Plat Review No.: 2nd Email: mazen.haidar@kingcounty.gov Project Number: L07S0018 Phone: (206) 296-7133 .,...,,.,.,_.,..,..,.,...-------------------r-ax: \LUo) L96 -6613 Project Manager: Peter Dye, P.E. Activity Number: L08SR020 -·---· - Sub Document Review Comments and Code Reference Consultant Response Date: a C 1l ") <.j Complete Item Item Reference 'I,? Name: Gina Brooks, P.E. , ~ '-1 IY/NI Sheet 5 1 Please revise the DOES Approval Block as shown in red on all Revised as requested. ~~· ,/ plan sheets except the standard cover sheet Sheet 7 1 In plan views please label Tract "A" as landscape tract Revised as requested. encumbering a public drainage easement dedicateil to King .,........ Countv for the R/D facilities Sheet 8 1 In the vault section details please show 5' X 10' openings for Revised as requested. equipments access with hinged man access in the RID section ,,/ of vault, and please make sure the vault structural plans are revised to reflect this change as well 2 Please clearlv label the control structure location on clans Revised as reauested. .. 3 Drainage Easement shall be shown within proposed Tracts A Tracts A and B labeled on sheet 7 as Public Drain. v and B Esm't to King Co. and Access Esm't to Kina Co. General 1 The submitted Geotechnical Report contains pavement See attached. section recommendation and it does not contain pavement ,)/J f>Y/11,r. .D~ v' design calculations, please submit three sets of these calculations for County review and approval as soon as R#""i?V..£ .f<-v .... hve. nossible. + r+f J ,f. "{f"'w.fil (!.; Please be informed that channalization and street lights plans Noted. f fo--A. review is pending for the subject project and full compliance -n---~ ~fp-v with review comments (if any) is required for the engineering . review annroval MJMr. 1 y/:z7/P'f 3 Please be informed that Constructability Review is pending for Noted. the subject project and full compliance with review comments V"" (if any) is required for the engineering review approval 4 Please refer to plans redline markups and revise accordingly Revised as requested. v 5 Please submit 3 copies of revised Civil Plans, revised vault See attached. Structural plans, and all County redline markups with list of ,/ resoonses to this list of comments ' ' I • £123RDST ;, ,, ' . Ii I '' .. · .:___--' .. ' . ;I I "--I '· I ........,"-. r-'""""" I I I , . I :· ::·, . \ -·:-·-·-·-·-·---·-·-·-·-·-·-·-·-·-·-· ·-·-·-·-·-·-·- ·, I ! \ .\ E XIS Tl NC FOCL/NE -- ' ' ' -i ' J \ 1 1' ' 'I ](]' ' ~ '\ , :-(J : I i ~lj'' i 1 · I ., , ' I : !1 . I ,-j +' I {D . ,, I I; ' I 1 1 ·HJ , 1 r 1 In I:;)." -; 0 I 01 a)~ (?.DIC::\ 0 --,/ I 25Lf !2"LC! .. ' ' T :-°: ' :_ . :, ' 'l . •• I ' ' . i 11 -::. c,l...O' ' ' CB2 T>1'£ I STA. 12+73, 21.25' RT. RIJ.I 516.18 STA. ·,(}+;7.jg_ PROP "aoiJNoARY STA .. 1o+S6, B£C1N '510£WALK . RAMP Flotw.JNE ELEV. ,31a6-I STA.-11+19.18. PC · CVR8 R£7URN flom.JNt \ El£' 512J8. 1.· I \ STA. 11+69 f 148111 A>f" SE~ \ STA. o+OO f ROAi) A I STA 12+18.fXJ, PT CURB Rf. !UP.N tl0Y.UNE £LEV. 515.00 STA 12+86. 70. ENO S/OEWAJ.K RAJ.IP FLOM/NE lif.Y: .... ~!6: 1~ -... i . 1 ... 12:.1£ .. 51J.i~ ... STA. 12+91.71, PROP !iOUNOARY CB 2A T>1'£ I STA., 1J+J9.83, 17.52' Rr- LOCAT£ O't£R £X1ST. CUl'lfRT. RIM 517.57 . 12" tE:515.M B RE!NF . HORZ & E 12)-#5 ,ARS@ THE 1NE 12-1/2 11 JRE POUR. 48 11 TYPE 2 CATCH BAS!N-----1 BASE . . SECTION @ SUMP /. SCALE N/A ..... ~·· ::-t· ~· ;:;:;: i ~ ·! t>; ...... r. STA. 9+3!, "19.8' ,r!c 501.ai · ··.,/.IATCH,EXISTJNC·" . DITCH flOHl,/N[ · ... CB'!. 'TYPE II,' 48"1 STA 10+62. -21.25: RT. , ( ·RJIJ·Sf0.80 · · · ' · · ·s~ 1£ sos.Bs. · · .c:s .~ ·/2' /£ 507.80 (II) , :_:.l;;; "12'.i£ 505.<6 (s.£r ;-.. ... ~, • OUTLET 18 · .~·~ .LfJCAT[. AS SHOHN. -~ :f2" IEfOS.59 i ' .. ' CB 2 . TYPE. J STA. 12+J3,)1.25' RT. ..• i, R!.2."! f/6:18 ; .. , ".,,..5/3.18,· CB 2A T'r?F-I : \ : SfA. ·10+47.39, PROP BOUNDARY 1 C . -·· STA ... !0+56,' BEGIN 'Sf[)£WALK \ RAMP FLOM.IN[ [l[V. ·Si06'f '. SfA. llf/9.18, PC, \. .CURB RETURN flOY.UNE .£LEV. 512.38 \ : .. \ .. \· STA. 11+59 f 148TH A i.t"" S[= I STA. OfOO f P.0/..D A ' STA. !2+!8.00, PT CURB Rt. TURN fWMIN[ [L[V. 515.00 STA . .12+86.70, [ND. 1 • SIOc."'wALK RAJ.IP FLOM.IN£ .Bf~ .5!6. ,:~. _ ......... STA. 12+91:l!, PROP iJOUNDARY ···· ..... , .. STA)JJ+J9.83: 11.52' Rr.··· (")' I ~c-,\· I ..... 5")~\ .\ . LOCAJ£,01;[R DUST.! CUL'r'ERT. · RIU 517.51 . !2"JE' 515.54 g@\I I i !',,~le' .. I .. a; ' ~ I Pleasant Path Page 2 of3 3. The utility poles relocation will require easements, and the pole relocation cost needs to be included in the bond quantity worksheet. 4. The frontage pavement widening will prompt an overlay (including prelevel) of 148th SE (an arterial) unless waived by the County Roads Engineer. The pavement crown and cross-slope varies along the frontage. As shown on the plans, a ridge appears at the proposed pavement joint along the frontage. The applicant should be prepared for more extensive pavement work than shown on the plans, and possibly revisions to the curb grade design, to address the anticipated requirement from KCDOT for a consistent 2% cross-slope in the overlay. 5. The pavement taper from the new sidewalk at the south end of the frontage is called out incorrectly to begin at the curb rather than from the back of sidewalk. 6. The vault outfall along the existing ditch along 148th SE is problematic. Placing it under the ditch causes the pipe crown to daylight as much as 40 feet along the downstream end of the pipe. This renders the existing ditch ineffective and out of compliance with the Road Standards, not to mention the pipe material needs to be ductile iron for lack of cover. It is clear the minimal pipe slope is dictated by the vault outfall invert. One way to address this issue would be to add a Type I catch basin at the end of the pipe, revise the ditch to a paved shoulder section with extruded curb along the length of the pipe, then provide a pipe stubout outfali from the added catch basin. Unfortunately, this would likely prompt an extension of the pavement overlay requirement along 148th SE due to the added paved shoulder. Another way would be to do the same installation but offset the pipe alignment from the ditch, the provide the stubout at an angle to the ditch, and maintain/restore the ditch to its current configuration. Please note there are existing drainage problems imme_diately to the south along 148th SE due to the lack of an existing pavement crown. Whatever solution is designed, it must not exacerbate the existing drainage issues downstream. 7. The outfall pipe in the 148th SE ditch requires a beveled end. 8. The steep pipe between CB3 and Inlet 3A creates problems where the pipe connects to the CB and the vault. A large elliptical opening in both is required to allow the pipe penetration. The Type I CB 3 may not have enough wall to accommodate the opening. The vault opening structural reinforcement requires specific attention. An alternative would be to move CB3 to the north, allowing a reduced pipe slope. There is plenty of room in the landscape tract to do this. A public drainage easement over the tract is already required to allow vault maintenance, so this easement would cover the conveyance at any location within the tract. 9. In the vault, the circular sump for the restrictor T creates a few issues. The sump is usually provided by the use of a Type II catch basin sump. This sump location typically conflicts with the vault footing. It also sets the T back from the vault wall, requiring additional bracing of the Tin the gap. This is apparent in the Restrictor Plan View detail (in conflict with the Restrictor Detail elevation view). Also apparent in that detail is the conflict wiith the required 2-foot clearance for the personnel access. The use of the Type II sump is suitable as long as these issues are addressed. I 0. I suggest the street tree plan will only require four trees at the frontage, rather than the crowded six shown on the plan. Mazen Haldar, P .E. Engineer II Department of Development and Environmental Services 900 Oakesdale Avenue SW Renton, WA 98055-1219 mf!z.en_,_bf!J!;h:ir@!s.ir:igc_QLHJ.tY .gov P 206. 296. 7133 F 206. 296. 6613 Office Hours M -Th 6:00 am -4:30 pm 03/31/2009 Pleas~t Path Haidar, Mazen From: grb@coredesigninc.com Sent: Monday, March 30, 2009 4:22 PM To: Haidar, Mazen Subject: Pleasant Path Attachments: 20090330160745690.pdf Mazen, Please see attached in regards to comments 6 and 9 below. Page I of3 6. Please review my 'red lined' profile for the outfall pipe. I am proposing to regrade the ditch flowline between the proposed pipe outfall and the existing culvert to eliminate the previously exposed pipe. This new ditch profile results in a worst case ditch that is 1 foot deep. The minimum cover over the pipe is 0.5'. Since this ditch will receive little drainage since all upstream drainage is contained within the pipe that this project is installing, I don't see an issue with the ditch being regarded with a worst case depth of 1' prior to the pipe outfall. As well, it doesn't seem necessary that this pipe should be ductile since it will not experience traffic loads except under the existing driveway in which case the pipe has 3' of cover. Please let me know if this design is acceptable. 9. Please review the structural design of the sump section for the control structure. Per the structural engineer, the sump will not affect the structural integrity of the footing that will be poured around it. Since this is the case, no revision to the location of the sump should be necessary. Moving the sump away from the wall will create a situation where the control structure will be difficult to stabilize. Please let me know if our current design is acceptable. Thanks for your help. Gina R. Brooks, P.E. Project Engineer Core Design Inc. 14711 NE 29th Place, Suite 101 • Bellevue, WA 98007 Tel 425.885.7877 • Fax 425.885.7963 httpj/www.coredesigninc.com • • • New From: Haidar, Mazen [mailto:Mazen.Haidar@kingcounty.gov] Sent: Tuesday, March 24, 2009 6:14 AM To: Core -Gina Brooks Subject: RE: Pleasant Path Hello Gina, Below are the constructability review comments we just received from the Land Use Inspection Services, please review and properly address these comments in your next re-submittal and let us know if you have any questions, thanks: I. The proximity of this project to the wetland should qualify it as a highly sensitive site and require a TESC supervisor. 2. The luminaire plan for the frontage will be reviewed by KCDOT, I assume. As shown, the luminaries are located on private property and would require easements. 03/31/2009 Pleasant Path From: grb@coredesigninc.com [mailto:grb@coredesigninc.com] Sent: Tuesday, March 10, 2009 4:50 PM To: Haidar, Mazen Subject: Pleasant Path Mazen, Last question ... I promise. Page 3 of3 On your comments list, you indicated that the drainage easements need to be shown on Tract A and Bon sheet 8 (Vault Detail Sheet). Tract A is an easement itself and no easement linework is shown. The easement line along Tract Bis shown but not called out. How do I address this comment. Do you simply want a callout for the easement line shown on Tract B? Gina R. Brooks, P.E. Project Engineer Core Design Inc. 14711 NE 29th Place, Suite 101 • Bellevue, WA 98007 Tel 425.885.7877 • Fax 425.885.7963 httg://www.coredesigninc.com • • • New 03/31/2009 , JLtttJ & ASSOCliATE§, ][NC. PrOject · Sheet No.-of_· FL6)(1e:.1..s f'A\)eM6Jr CG51(3tr!p.No. · Geotechnical Engineering • Engineering Geology • Earth Science 19213 KENLAKE PLACE NE • KENMORE, WA 98028 fl-A1 Of--: f\fA~t.!T PA'.11:1 PHONE: (425) 483-9134 FAX: (425) 486-2746 DESIGN CALCULATIONS ROADWAY FLEXIBLE PAVEMENT PLAT OF PLEASANT PATH 12204-148TH AVENUE SE RENTON, WASHINGTON ®@©@G\;{l@@ t,.PR 1 3 '/009 &<.C. o.o.e..s. Date i .. LIU & ASSOCIATES, INC. . .· I "2..- Project . · . ·: Sheet No.-of_ EL 6x Ubl b f'A\/©16NT W$JC1tr!p. No, __ _ GeoteChni~l"Engineeiing_ • Engineering Geology • Earth Science 19213 KENLAKE PLACE NE • KENMORE, WA 98028 PHONE: (425) 483-9134 FAX: (425) 486-2746 PLA1 of: ftf.ASANT PA-rH Date · i:::LG)<..le.L.E:. f"AV~MGr-lj DGSIG)ts\ f~ eASr:::po"1 EMf'l~CA1--ME;;iHoD . . . . . . . . . . l . 1i,.l 1' 1493 A.A.SHTo G!Ll\OE:. Ft::RDGSl6)N at:=: f"~\/1::;MGN.1 S1~t.JC:f0~i;t..? OG-~1(:ji-.J fAMMGfeRs : •. -ry.p~ oi:. RoAD: \)~SAt-J ~.51DGr-l'T'1A.'-1 o,-../G .L..:A-i-.!E:o EA, DIRGC..TioN ]<Afflc. Ot~'fR.1 ~U11otJ~ loo% 6~ Lof.l,.,D1tJGt IN D;;~l~IJ LAtJG D~SIGti.J f'GRlo D; :io Yvs .. · Ar-!t..lu.t,..1..-~Row1"i-·1 RAfE..: .2 % i-ot-lS'fR t.ll-'f1o 1-l MA16R I ~L .: 1"R:,'~ HMA SuRi:-A-c.~ CouR~~ :. 3. "> ...-11 \-1 M.o-lbASG Col.J~E; : 2_!1 t:5. c~e:. : <a'' 0u¢:,§RAGo ( rre~h-n1I ~1l<>) 5tJ~ 9><ti,44+ ~><o,1"3 =-z:q12 1"1~-:::-I b/ooo psi: ( SuMVV\e,v' &; . ~II) ... . ::::: q 1 ooc, f'St ( cJtvi+.e,.,-2.. '>1"'V1V15) Dv6J2.ALL ~6R,\/IO?P..l?,I u-ry Los.~ , D fSl=-0 o_ ,1, · . . -' ro-rf-,.s-3,o .::.\,6 ·. Rtat..\f!-..ts11..-1-ry: r< .::-qo '%, . . . OvSAAU-S.-rANDARO 06JtA1io"'1 1 S 0 :::: o,C5o -r RAFF-/ c C-o cJ r,l,JT : . · . · w ~ · f j;./,ses/ 4A~e,M~ "[1<.iJc-k (:S111 ~l.e JV\ if):::: 2. e.o-/wKX 2 '>< '54 ~ '2.1 6 /"( v' i:;1.Re-E.i-l~1i-\G·flevvk(DG>.i\.k.U11:+) =::.. lo ~-'ef'(v . · . _;, Mov I N6i -rR.uc k. ( Dt> u blR. tJ.,,1:f-) :=;_ 2 HoVM.I X 3 (rVV,,.(1/'f< =' vt~sses('rv: l ~t)l. ( <-I l'<A I t-l -;. :::::. o . . GSAL..s-::::: '2.lb'l<t>,4o-r ((ot14)xl,01:1.=: t2c,/yv Pe~,4 .J ~~AL~ -=-( (+GJ) ':.. 1 >< 1 ~ °'J .;:. G +o. t!2 .. sz~ I X ( 'k> :;:; . 2 ., I b / y V" ~ o.~z 1· A1 USE; -c;:f(_~ ::: Gooo {1v. "Lil.U & ASSOCIATES, INC. . 0~ Project Sheet No. -of_. _ Geotechn'ica! Engineering • Engineer:ng GeolC>gy ~ Earth Science EL6xtlbl h f'A\/E::t:'.l@r C65(4tr!p. No.-~- PLAr of: ftfASAtlT PA1J:l 19213 KENLAKE PLACE NE • KENMORE, WA 98028 PHONE: (425) 483-9134 FAX: (425) 486-2746 -~---,--,-----Job No &>Ao"f B By ..j$L. Date -;/27/oj Ck'd by Date · b~c11vf:; $0r?.G/f<'.'.ADG RG~1Llf;NT Mo:DuL-US( e,J~tww we;') 4+eJ) f:~e-M::::::. (e.8~x'1,ooo -\-0,'jl,>( 'f,o 00 fkoxl~ooo -f0,46.,.. rqooo; '1"4 :;::: ~,{:,'to p.s~ u~e A&Dvf; PAt<AMGf~~ IN --nf6 ~U.OWIN~ e&UAT10"1 ~ lo5lO(v:rj~ )'=-t:«_ x '=>o + "1, lb)< ID5 ,o(s~+J..)-i,,-z.o + . k>' (6FS1-) -01 1:~.,,f,~;! + 2,!,2..>< /05 10 (M~)-8.ol (SNf,) S,/4 ~" uJ~ ro~ ~t,.J, ~~ SI..! ~I, lo ~ . u 1CZ.Y: f-{MA ~o"0A-c..G c:.cu~SE:.: (.~ HM A ~A.;G l'.ooRse: : I u · G-R. e:. : 1.,." ~~ = ( /:~.,-I )o, 44 f 2>< o, \ 3 ::. /, "3 b LI SG-fl-IE:: W6w -r12..1 P.. L s r--.1 :::. I, 5'"z,. At.lo ll(~o\J G:: 'D G-! I ~ ".\ f'A RA me·re ,zs . IN i!-10 P.. P:::oVE; <::;61..v Ai11Dt--l 2,.. S-of..,.oJ E St-! />61 A 1,.J 1 l\etd ~iJ~ (.lo -:=(.sf. SK., Jt..o eiG l> -k · 000 vefi...i t...1 l::tl-l r i"'~ i:f t c. C.o u \J f I. JL::n:u & ASSOCIATES, liNC. PrOject · Sheet No. -of_· FL6~((bjf; f'A\/E;;MM Q?Slcytr!p.No. · PL.Ar or::-f\bA~tJr PA11:l Geotechnical Engineering • Engineering Geology • Earth Science 19213 KENLAKE PLACE NE • KENMORE, WA 98028 PHONE: (425) 483-9134 FAX: (425) 486-2746 --~--.--.-~-'--'-~Job No &>AD "f B By .__l$L. Dato -;f z7 / o'j Ck'd by DESIGN CALCULATIONS ROADWAY FLEXIBLE PAVEMENT PLAT OF PLEASANT PATH 12204-148TH AVENUE SE RENTON, WASHINGTON ffi1rn@rnowrn@ APR · 1 3 rllilQ OC.C. 0.0.E.S. Date I LillJ & ASSOCIA'fJES, INC. Geot€:!Chni_~,-Enginee'ring_ • Englnet3ring Geology • Earth Science ---I "2--Project . · .: · · Sheet No._of_ EL€;.)( 1 e:.1 h f'A,/et-16Jr G,sita~P-No. __ ~ f'LA1 op f'Lf.ASAt-lT PA1:H 19213 KENLAKE PLACE NE • KENMORE, WA 98028 ----~-.-----Job No ~Ao"IB FAX: (425) 486-2746 · --:.;J / 4 PHONE, (425) 483-9134 By .J SL Date ?('27 6 Ck'd by Date · i:;L-Gx.1 (;LE:, f"AVG-MGt-J1 DGSIG)N (~ @ASE;.!) ON e:Mf'lf<LCAL-ME;:;-1H0D . . . . A . IN -1' (9"13 ,AA.SHTo Giu1DE--FcRDi;;sr&,N oi:: f"~VE;:-MG-t--1.1 ~"f~l)G"fv~EA,.~ oe-~1qi--J f'A~MGfe~s: _ _ _ _ . _ -fyp~ oi:: RoAO: l)(<.SAi-l R!;--S1D(;r-l11AL-1 ONS _l.ANE:o EA, DIRGc..TioN 1R.AF-Ftc. Dl!.ft<.l tsU"fioi.J~ (oo % op LoADliJ~ IN CG~\eqtJ LA~& D~SIGjN PGRlo D: 2-0 Yvs . _- At,h.l U/:>.t... &iieow-ri-1 RA.f1:;,: 2 ro &ot-lS1"RUC::-"f1ot--! MAfE;Rlf-1...L: 1"<Z,'~ 1-lMA-SuRPAcG:::-Gou.R!.~ : 3_ · •r> ... ,, rl M /.>. ,; A. SG Co U ~ e;. : z." t:j C ~e, : <.:,'' 0ue.§RAG-(h'e~h '1'~11 ~\\~) St-l~ 9xo.44+ - b:X.t>,I?. ==-'Z~Oi~ t'1 f!.. =-I bl Ooo rs t ( s I)~ YI'\ e,v' &;'. . ~-_I\) . . . :::: q ooc, rsl· ( wtvi+..e,,-2-Sl""V1Y\5) -I Ov6f2.Au_ ,;GR,\/(Ct?f-:\l?,1 l-11"'( W)SS. ~ D rs1::::. Po-fl--=-A. , _.., -1· ,;.- . -,; "T • :, .;,,O -•? ·_ R6t-\t-\f3.IL-l"f)': (<;.-qo,Y0 -. -- OvSAAw... $-fANDA~D DG-VtA1ioN, .s~: 0,'?o 1 RAFYI c c.o cJ ~T : _ . _ -_ w ~ -ff>..1,5ts/ &°A~&M~ "f1<.1Jc-k(S1n~l.e Uni+)== 2.r?;A/wKXZ.Y.'?4 ~tlb 7'f,.; o· ~IRE:, 8-N.6pt-l.G-r~vol::.(Dc>1..1'bk(.)l'l:.f--) .:::. lo fAf.l'.o/'(v-./. Mov IN 6i "TRu Ck. ( D6 u blR.. UV)(+-) ::::.. . ~ Hov-rw X 3 it,w;/'f,;:: ,z.4~ sse.y 'fv: r~ul--1'-1 AA1 !'-1,;. ;::,. 0 _ . G.SA.L...s -::::: '2.(b">< o,4o+-C10+24-)x!,o~= t2.o/yv Pe~1ctiJ G-sAL~-=-((+~)~t °J ></2-o -z::. (I +o. oz..)°Z~ I X ("k ::::: 2 C) I bf y v- / O,<>z /' '7A"( l)S~ v!(_:3 == 0000 /Yv, 0 "2,.... Project --. Sheet NO,-· _of_ EL6)(ilblh fAVei:::16.Jr C6$!63tr!p.No. __ _ , LRU & ASSOCRATJES, RNC. Geotechnical Engineei"ing • Engineer:ng Geology • Earth Science f'LA1 Of-: f\EASA~T PA:r:H 19213 KENLAKE PLACE NE • KENMORE, WA 98028 PHONE• (425) 483-9134 FAX: (425) 486-2746 Date -G'r::r::c-c.11.Je ':,L)e.G,RAOG R~~ILl~tJ-r MtfDut..,US( c.J~-f{ow we:5 4-f-ec.Q) ~R.e-Jk:::. (e,gSx'i,oao +O,'T)C '1,oo 0 fko)(IC';ooo -t0,46-,. (1',o6oJ '1"4 ~ ~,~/to p.s~ U~e A&Dve: PAl<f\MG-f~~ IN 11f6 h:>1.1..otJt~~ E&UAT1oi-l ~ lo510CWi6 }-=-t:f\x S0 + i, >bX l05 10(Sts.i+J..)-0,"2-o t \05 ce.rs1-) -0 , 1:~.,,f1~4f + 2,~2..X /0~10 (M~) -&.ol (SNf/)5,/4 ~"' u) f (o~ L;. 1') 1 . ~8td Si,.! :::-I, ! 0 ~ . . ,r..y: fiMA <SoR~c.G Gcu~se:.:: (.,; HM/).. ~A~G l'.o<.>R;Se:; : 11' ' C.R. e, : .z.'' ~~ -=-.( 1;~.,., )o.44-tZ><,Gl,!s =-I· '3b tJ~ f!-10 tJEw 11'2JP.L s,....I ::. I, 5'£>. Ai-Jo AP.;ol/f::: 'i)G--Sl(1~ PAMl'\'\E-re~s. . IN TI-IG-P..fl:::oV0 G6luA1"1t0"1 2,.. S-ol..,\JG St-! />61A1N 1. l\etd. ~N = /'.IO ~ (. 3b ,!fe~~f=z>R~, fAv~ME-iJ-r'DG~(~iJ Z)~ ·. ~ \,i.' MMA. St>Rt=:-Ac.6 (..,ou.f<. >i::. J / 11 HMA r'.3iAS~ Cou~SG-. 1.l' <'.:,(~J::, . -' - SH., Jt,O /!)G O ,k · DuG-ve{l...,'-f t....1crHr l~q-lc. u,O\Jj" f-Br'Z. LoiJ~/Zv'AftVE, Pu~f'o~<:;-; US.f;: { ~/'HM/.\ ~f!.PAC..6 (,Qc.){Z!:'G-} As RE-(.,ow,W)G.:"108> 1. '' 1111 A e,.1:i.;s(:;: . I tl LIV & P..SS.0, (c,1' CL6. , , /r L-/ZoDS ~G-of&-C(..!N(LAC (~o~f I I I I I I I I I I I I I I I I I I I ~ ~OffeJJE ~DESIGN Core Design, Inc. 1471 J N.E.29thP/ace,Suite 101 Bellevue, Washington 98007 425.885.7877 Fax425.885.7963 www.coredesigninc.com 'flECHNliCAlL liNJFOJRMA 'fliON RlEJPOR'f ('f .li.R.) Prepared by: Reviewed by: Date: Core No.: FOR lPlLlEA§AN'f JP A 'fH KING COUNTY, WASHINGTON Nathan W. Driggers, E.I.T. Gina R. Brooks, P.E. April, 2008 06083 00 [g@[gOWrn@ APR 28200B K.C. D.D.E.S. \..-0~~~ hCJl-S>oO\S{ ENGINEERING PLANNING SURVEYING I I I I I I I I I I I I I I I I I I I KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND · PROJECT ENGINEER ., ,. Project Owner :P &<,o,i\t p,,Jh , L~ Phone ('tZSJ 78'.S-2 870 Address g~~~~:wi:1:t~ ~~~n~~ Project Engineer r"T im ?irn::Js~ P£ Company Core l}.'>i13y\, , 1-C(I Phone Lf2 ·Y1'-i..~·~':l',~: _. ''>~--· _.,. , ... ~~-_t;;_"r:.:n~:;,t;.;,~.·'t,\;,L:..ot;.:::;_:'· .-:~<•;t -, :..: t· ·...;.;r. -~ 'F'art 3'·'TYPE.OF· PERMFf;Af1Rl:ICATION '., • ... · .. ', 1-W..i,;,;......>;--,_-.;+.,,.,.,.~ _, ';'r.:;.~, .... ~~Y.~~':1~t'-~;:;-~~ .. ,. "'.-'°:"":·,t .,_;_..: • ;._ ·1!,;.& 15<1 Landuse Services I ~ubdivison'I Short Subd. / UPD 0 Building Services M/F / Commerical / SFR !&I Clearing and Grading J2sl" Right-of-Way Use D Other Technical Information Report Type of Drainage Review fFuli) / Targeted / (circle): Large Site Date (include revision dates): Date of Final: ~.ta?E? pJ{{:i;R9J9Tl()CATIONAND?. ··,, DESCRIPTION. . . ., .. : .• -_~._. .... . '":" ·' . ,. l'. .. Project Name Pb,e:,:,,,v\ P«-lli DOES Permit# l-07 soot B' Location Township l '!J N Range SE Section _ __,/~// ___ _ Site Address l l?.{Yf /Cl6t='-A-1~ ~ :1,·c4~rf~'Wtd:i·-?'i!j·~·, ;,-~.-f_ •. :: • ·j· ·: .• , .•. :::, .. ,,,:,. >:·~,,:7/ri.'!tWi•.fi~i-.: :,-; f :,~ap.~~<2,X.~J,~,R~\LE;,10{~ ~~P:~~~~l?tk : • 0 DFW HPA D Shoreline 0 COE404 0 DOE Dam Safety 0 FEMA Floodplain D COE Wetlands D Other __ _ Management J2I Structural RockeryNault/ __ D ESA Section 7 Site Improvement Plan (Engr. Plans) Type (circle one): ~/ Modified / Small Site Date (include revision dates): Date of Final: 'f/1.coB Type (circle one): Standard / Complex I Preapplication / Experimental I Blanket Description: (include conditions in TIR Section 2) Date of Annroval: 2005 Surface Water Design Manual 1/1/05 I I I I I I I I I I I I I I I I I I I KJNG COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Monitoring Required: Yes I No Describe:-------------- Start Date: Completion Date: . '.,,.,,- , :J;_ ":- -~ \ .::-)· 7;.j,.-,-. Community Plan : -'-~"""°"'"'"''o:Du~--"\e..""----------- Special District Overlays:------------------------- Drainage Basin: ---1::,l.~o~w,,1:e~r~~!Q!;';L_Jfil'.cL.:__~~- Stormwater Requirements: :tr<> 0 River/Stream _________ _ D Lake ~ Wetlands lt'etlc.oJ I 3123 ~ 0 Closed Depression _______ _ 0 Floodplain __________ _ 0 Other ___________ _ Slopes 0-15% 0 High Groundwater Table (within 5 feet) 0 Other _________ _ D Additional Sheets Attached 2005 Surface Water Design Manual 2 0 Steep Slope ________ _ 0 Erosion Hazard _______ _ 0 Landslide Hazard-------- 0 Coal Mine Hazard _______ _ 0 Seismic Hazard _______ _ 0 Habitat Protection-------- 0 __________ _ D Sole Source Aquifer D Seeps/Springs t/1/05 I I I I I I I I I I I I I I I I I I I KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET ' .· '.· . Part 11 DRAINAGE. DESIGN LIMITATIONS ' .-, " . · .. REFERENCE LIMITATION/ SITE CONSTRAINT D Core 2 -Offsite Anallsis D Sensitive/Critical Areas D SEPA D Other D D Additional Sheets Attached . . : : _, . ,·, ., . _·.: ··; --. ' _, . :. '-. ·: -->:· .. ' ,' . :·· _· ' ' ._ ':':-·-:·-' . -:··· .. -· Part 12 TIR SUMMARY SHEET . ,;;,~;ideone TIR Suinman, She~t perThreshold Di~~haioeAi~i)' . , .. -. Threshold Discharge Area: /name or descrintion) :Pl~/\\ Vw\~ ~)r~ Core Requirements (all 8 apply) Discharne at Natural Location Number of Natural Discharae Locations: I Offsite Analysis Level: C!.)2/3 dated: 1/_ ?,q/?DO "7 Flow Control Level: 1 / (J) I,}, or LY.xemption N,umber /incl. facilitv summarv sheet) Small Site BMPs r··· ~ Conveyance System Spill containment located at: Erosion and Sediment Control ESC Site Supervisor:Qc,l\\1ucAor" -\o Contact Phone: ~i~NA.-k.- After Hours Phone: Maintenance and Operation Responsibility: Private / Cl-'ublic, If Private, Maintenance Loa Reau ired: Yes I No Financial Guarantees and Provided: Yes I \!::!.g) Liabilitv - Water Quality Type: (Basic l Sens. Lake / Enhanced Basicm / Bog (include facility summary sheet) or Exemption l'fo. Landscaoe Manaaement Plan: Yes I No Soecial Reauirements ( as annlicable) Area Specific Drainage Type: CDA / SDO /MOP/ BP/ LMP / Shared Fae. ( None_) Renuirements Name: Floodplain/Floodway Delineation Type: Major / Minor / Exemption / ~ 100-year Base Flood Elevation (or range): Datum: Flood Protection Facilities Describe: Source Control Describe landuse: (comm./industrial landuse) Describe any structural controls: 2005 Surface Water Design Manual 3 1/1/05 I I I I I I I I I I I I I I I I I I I KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Oil Control High-use Site: Yes/~ Treatment BMP: Maintenance Agreement: Yes / No with whom? Other Drainaqe Structures Describe: . Part 13 • EROSION.AND SEDIMENTGONTROL REQUIREMENTS ·_:: __ =-.:: ·.:··,. '·_ '' MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION ~ Clearing Limits Qs:I Stabilize Exposed Surfaces i2Q Cover Measures Qi;! Remove and Restore Temporary ESC Facilities G!) Perimeter Protection ~ Clean and Remove All Silt and Debris Ensure l8J Traffic Area Stabilization Operation of Permanent Facilities ~ Sediment Retention 0 Flag Limits of SAO and open space l;8;I Surface Water Control preservation areas 0 Other W Dust Control ~ Construction Sequence Part 14 STORMWATER FACILIT'i\ DESCRIPTIONS (Ntite:·lridude facilitv Summarv and.Sl<etch);•· < . Flow Control Tvne/Description Water Qualitv Tvne/Descriotion l2S'I Detention y_0,u\i 0 Biofiltration 0 Infiltration ia-wetpool u;Q\ ~AAtt 0 Regional Facility D Media Filtration 0 Shared Facility 0 Oil Control (ia Small Site BMPs ~{)v\~~Jt'"'IT 0 Spill Control D Other ~ Small Site BMPs ~~~ t16~e"' 0 Other 2005 Surface Water Design Manual 4 111/05 I I I I I I I I I I I I I I I I I KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT {TIR) WORKSHEET Part 15 EASEMENTSiTRACTS Part 16 STRUCTURAL ANALYSIS ·,' .. . . ~ Drainage Easement l2sJ Cast in Place Vault ldl Access Easement 0 Retaining Wall 0 Native Growth Protection Covenant 0 Rockery> 4' High ~ Tract 0 Structural on Steep Slope 0 Other 0 Other .Part 17 SIGNATURE OF PROFESSIONAL ENGINE.ER• I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the in!or · ovided here is accurate. 2005 Surface Water Design Manual 1/1/05 5 I I I I I I I I I I I I I I I I I I I PLEASANT PATH TABLE OJF CONTENTS 1. Project Overview 2. Conditions and Requirements Summary 3. Off-Site Analysis 4. Flow Control and Water Quality Facility Analysis and Design 5. Conveyance System Analysis and Design 6. Special Reports and Studies 7. Other Permits 8. CSWPPP Analysis and Design 9. Bond Quantities, Facility Summaries, and Declaration of Covenant IO.Operations and Maintenance Manual I I I I I I I I I I I I I I I , I I I I 1. PROJECT OVERVIEW: Pleasant Path is located in SW V. Section 11, Township 23N Range SE on J4gth Avenue SE, 0.3 miles north of the intersection of 148th Avenue SE and SE I 28th Street in King County, Washington. See Figure I and Figure 2 on the following pages. The property will be made up of tax parcel l 123059092 and 11230590 IO to create a property size of 4.54 acres. The parcels are divided by a wetland area. Only the 1.52 acres west of the wetland buffer will be the developed Pleasant Path. The site is bordered by 148th Avenue SE to the west, single family residences to the north and south, and wetlands to the east. The site is currently occupied by a single family residence and outbuildings. Ground cover is predominately grass and landscaping with gravel vehicular access. The entire property slopes to the southwest and sheet flows to the west property line. The eastern boundary of the site is the boundary setbacks of a treed and heavily brush covered wetland. The King County Basin map shows the runoff from the property flows into the Lower Cedar River basin. See the Downstream Analysis in Section 3 of this Report for a description of the downstream system The proposed project includes constructing 8 single-family residential lots with associated roadways and utilities on 1.43 acres of the property. All existing structures will be removed. Access to the site will be via 148th Avenue SE. Half-street improvements on 148th Avenue SE along the property's west frontage, including pavement widening and installation of curb, gutter, and sidewalk, will be completed as part of the project. Developed drainage will be conveyed to a proposed combination water quality/detention facility that will be located in the southwestern comer of the property. The facility will discharge to an existing ditch downstream and south of the property within the 148th Avenue SE Right-of-Way. The site is subject to the Conservation (Level Two) Flow Control and Basic Water Quality requirements within the 2005 King County Surface Water Design Manual (2005 KCSWDM). I I I I I I I I I I I I I I I I I I I Figure 1. Vicinity Map VICINITY MAP NOT TO SCALE ------------------- Figure 2. Drainage Basins. Subbasins, and Site Characteristics King County Water Features __. w~tvn"-d 0,;~:,y ._-11.:r..tn l.lound:ary ....--~· . ...- ........-Stro>i]flt ' ' in«<p<Hlled A,.,.., ,'/ / ~ '· ,: .. _ ~ , _f/ '. ,,.,,. ,, --~~' \ ·, -.., ~ake,Washington/ · ,.....--<__ Cedar River .... ' / ~-~, '"Y<;1tei:sl)ed ..tY'i ' ~ "'·---~ '- I I I i I I I I I I I I I I I I I I I 2. CONDITIONS AND REQUIREMENTS SUMMARY: Attached on the following pages are the conditions of approval and Road Variance (File No. L07V0022), H. DECISION: Proposed Short Plat File No. L07S0018, received and revised on July 3, 2007 as described by Attachment I of this report is GRANTED PRELIMINARY APPROVAL; subject to the following conditions of final approval; 1. Title 19A a. This short plat will comply with all of the Land Segregation provisions of King County Code (KCC) Title 19A. b. The final short subdivision recording documents must be prepared by a professional land surveyor, licensed in the State of Washington. These documents shall comply with the conditions of the approval listed in this letter. c. The final review process must be completed prior to the recording of the short subdivision or the sale of any lots contained within. The Department of Development and Environmental Services (DOES) strongly recommends that the Final Short Plat review package be submitted to the department at least one year prior to the expiration date of the preliminary approval letter. d. All persons having an ownership interest in the subject property shall sign on the face of the final short subdivision. e. All utilities within proposed rights-of-way must be included within a franchise approved by the King County Council prior to final short plat recording. Prior to recording KCC 19A.08.160 requires that the following is required: f. Prior to recording KCC 19A.08. l 60 requires that the following site work is completed: I. Drainage facilities and erosion control measures are consistent with K.C.C. 9.04.090; 2. Water mains and hydrants (if required) are installed and fire flow available; 3. Grading as necessary so that all the lots are accessible by passenger vehicle; 4. Specific site improvements are completed that are required and conditioned prior to plat recording or required to remove and safety hazard; 5. Undeveloped critical areas are delineated. 2. Surface Water Management (KCC 9) 2005 King County Surface Water Design Manual (SWDM) I I I I I I I I I I I I I I I I I I I The proposed short plat qualifies for full drainage review as outlined in Chapter I of the SWDM. Final short plat approval shall require full compliance with the drainage provisions set forth in King County Code 9.04 as proposed in the conceptual drainage plan for this short plat. A professional civil engineer licensed in the State of Washington shall prepare drainage plans and a technical information report as outlined in Chapter 2 of the SWDM. The engineering/drainage plan submittal shall demonstrate compliance with all applicable core and special requirements. Compliance may result in reducing the number and/or location of lots as shown on the preliminary approved short plat. Preliminary review has identified the following conditions of approval, which represent portions of the drainage requirements. All other applicable requirements in KCC 9.04 and the SWDM must also be satisfied during engineering and final review. a. Drainage plans and analysis shall comply with the SWDM. Prior to short plat recording, the applicant shall submit drainage and engineering plans to address the required short plat improvements. King County approval of drainage and roadway plans is required by county codes and policies. Bonding for the drainage plans will also be established as determined by DDES prior to plan approval. After receiving drainage plan approval, the applicant shall contact the DDES Land Use Inspection Section to schedule a pre-construction meeting prior to performing work on site. b. Current standard plan notes and ESC notes, as established by DDES Engineering Review shall be shown on the engineering plans. c. The following note shall be shown on the final recorded plat: "All building roof downspouts and drains from all impervious surfaces such as patios and driveways shall be connected to the permanent storm drain outlet as shown on the approved construction drawings # on file with the DOES and/or the Department of Transportation. A copy of this plan shall be submitted with the application of any building permit. All connections of the drains must be constructed and approved prior to the final building inspection approval or certification of occupancy. For those lots designated for perforated stub outs, dispersion, or infiltration systems, the designs shall be constructed at the time of the building permit and shall comply with the plans on file." d. Storm water facilities shall be designed using the KCRTS Conservation flow control standard. Water quality facilities shall also be provided using the basic protection menu. The size of the proposed drainage facility and tract may have to increase to accommodate the required detention storage volumes and water quality facilities. All runoff control facilities shall be located in a separate tract and dedicated to King County unless portions of the drainage tract are used for recreation space in accordance with KCC 21A.14.180. 3. Road Standards (KCC 14) 1993 King County Road Standards I I I I I I I I I I I I I I I I I I I Roadway improvements are required to address access requirements and impacts to existing roads and right-of-way. All construction and upgrading of public and private roads shall be done in accordance with the 1993 King County Road Standards established and adopted by Ordinance No. 11187, as amended (KCRS). The proposed short subdivision shall comply with the KCRS including the following requirements, unless otherwise approved by DOES: The extent of improvements ( conditioned below) requires submittal of engineering plan and profiles and appropriate review fees. Plans shall be prepared and stamped by a professional engineer licensed in the State of Washington and contain the applicable elements outlined in KCRS and/or the 2005 Surface Water Design Manual (see Section 2.2.2). Please note that the applicant should submit the plans a minimum of one year prior to the preliminary approval expiration date. a. 148th Avenue SE is classified as an urban collector arterial (KCRS 2.02). Urban frontage improvements (including curb, gutter and sidewalk) shall be constructed along the frontage. There shall be no direct vehicular access to 148th Avenue SE. A note to this effect shall be placed on the final recorded map page. b. The onsite road improvements shall be designed to conform to KCRS 2.03 for urban minor access roads. The improvements include: 22 feet of paving, curbs and a sidewalk on one side and one foot of right away width behind the sidewalk and curb. The intersection shall conform to the location of the approved variance (L07V0022) at 169 feet north of the centerline intersection of 148th Avenue SE and SE !23rd Street. c. Tract B shall be designed as a private access tract (PAT) serving proposed lots 6,7,8 and the future development Tract E. These lots and tract shall have undivided ownership of the tract and be responsible for cost for its maintenance as a prorated share of the number of dwelling units that use the tract for access. Improvements shall conform to KCRS 2.03 for urban minor access roads which include 22 feet of paving. The minimum tract width shall be 26 feet with a maximum length of 150 feet. d. Tract C (if required) shall be improved as a private joint use driveway (JUD) serving lots 6 and 7 and the future development Tract E. These lots and tracts shall have undivided ownership of the tract and be responsible for the cost of its maintenance on a prorated share of the number of dwelling units that use the tract. The tract will be configured to allow the construction of a 2007 KCRS alignment of a private access tract roadway. However, only the 1993 KCRS JUD will be required to be constructed for this short plat. As specified in KCRS 3.01 C, the driving surface shall be paved 18-feet in width) and have a minimum length of 20-feet measured from the edge of tract "B". Please look under ODES application packets at www.metrokc.gov/ddes/forms for detailed information on driveway connections. An ingress, egress and utility easement or tract can be extended from Tract "C" across lot 6 to tract "D" for the benefit of the owner of tract "E". The easement or tract shall be configured to allow for construction ofa 2007 I I I I I I I I I I I I I I I I I I I KCRS private access roadway (2005 KCRS 2.09) and this tract can be combined with the PAT "tract "B". e. Tract F within the wetland shall be created to accommodate a future 2007 KCRS (2.09) private access roadway from tract C to tract E (if the owner(s) receives approval to subdivide tract E). The tract shall remain in a native state until the Department of Development and Environmental Services (DOES) or succeeding agencies approved the construction of a roadway including a wetland mitigation that would be required by the approving agencies. See conditions 11(1) and l l(L) ifan alternative access is provided. f. A cul-de-sac bulb shall be provided at the east terminus of onsite road consistent with KCRS 2.08. g. The property line at the intersection of the onsite road and 148th Avenue SE shall have a radius of 25 feet per KCRD 2.1 O.A.4. The intersection shall be constructed to urban minor access street standards. Modifications to the above road improvement conditions may be considered by King County pursuant to the variance procedures in KCRS 1.08. Any request for a road variance shall be submitted to ODES on the appropriate form and with the minimum fee deposit. Other engineering details that may be shown on the preliminary site plan with the exception of the above mentioned may not have been reviewed for compliance with KCRS. If differences exist, the final design shall be modified to meet KCRS. 4. Site Improvements Inspections, Fees and Financial Guarantees (Title 19 & 27 KCC) This short plat was conditioned to construct/reconstruct road access/right-of-way improvements and/or drainage facilities. Approved engineering plans, inspection fee and applicable financial guarantees are required prior to either starting construction or recording this short plat. At the time of engineering plan approval, you will be notified of the fee amount that will be required to inspect construction and the amount shall be deposited with DOES and the financial guarantee amount(s) required prior to scheduling of the pre-construction meeting. Please note that the pre-construction meeting is mandatory prior to the start of any work (including site clearing) or the recording of the short plat. 5. Health (KCC 13) This project is exempt from further King County Health Department review. However, if improvements are required from the sewer and/or the Water District, then verification shall be required from said District(s) that the improvements have been bonded and/ or installed, prior to final recording of the short plat. 6. Building and Construction Standards ( Title 16) I I I I I I I I I I I I I I I I I I I A. The applicant shall comply with all the applicable provisions of KCC 16.82. B. To implement KCC 16.82 which applies to the site, a detailed tree retention plan shall be submitted with the engineering plans for subject short plat. The tree retention plan and engineering plans shall be consistent with the requirements of KCC 16.82. Flagging and temporary fencing of trees to be retained shall be provided, consistent with KCC 16.82. The placement of impervious surfaces, fill material, excavation work, or the storage of construction materials is prohibited within the fenced areas around preserved trees, except for grading work permitted pursuant to KCC 16.82. 7. Fire Code (KCC 17) Section 902 of the 2004 Edition of Uniform Fire Code The applicant must obtain the approval of the King County Fire Protection Engineer for the adequacy of the fire hydrant, water main and fire flow standards of Chapter 17.08 of the King County Code. 8. Zoning Code (KCC 21A) A. Density and Dimensions (KCC 21 A.12) All lots shall meet the density and dimensions requirements of the R-4 zone classification or shall be as shown on the face of the approved preliminary short subdivision, whichever is larger. Minor revisions to the short subdivision, which do not result in substantial changes and/or do not create additional lots may be approved at the discretion of the Department of Development and Environmental Services. B. Street Trees (KCC2 l A.16) Street trees shall be provided as follows (per KCRS 5.03 and KCC 21 A.16.050): a. Trees shall be planted at the rate of one tree every 40 feet of frontage along all roads. Spacing may be modified to accommodate sight distance requirements for driveways and intersections. b. Trees shall be located within the street right-of-way and planted in accordance with Drawing No. 5-009 of the 1993 King County Road Standards, unless King County Department of Transportation determines that trees should not be located in the street right-of-way. c. If King County determines that the required street trees should not be located within the right-of-way, they shall be located no more than 20 feet from the street right-of-way line. d. The trees shall be owned and maintained by the abutting lot owners or the homeowners association or other workable organization unless the County has adopted a I I I I I I I I I I I I I I I I I I I maintenance program. Ownership and maintenance shall be noted on the face of the final recorded plat. e. The species of trees shall be approved by ODES if located within the right-of-way, and shall not include poplar, cottonwood, soft maples, gum, any fruit-bearing trees, or any other tree or shrub whose roots are likely to obstruct sanitary or storm sewers, or that is not compatible with overhead utility lines. f. The applicant shall submit a street plan and bond quantity sheet for review and approval by DOES prior to engineering plan approval. g. The applicant shall contact Metro Service Planning at 684-1622 to determine if 148th Avenue SE is on a bus route. If 148th Avenue SE is a bus route, the street tree plan shall also be reviewed by Metro. h. The street trees must be installed and inspected, or a performance bond posted prior to recording of the plat. If a performance bond is posted, the street trees must be installed and inspected within one year of recording of the plat. At the time of inspection, if the trees are found to be installed per the approved plan, a maintenance bond must be submitted or the performance bond replaced with a maintenance bond, and held for one year. After one year, the maintenance bond may be released after DOES has completed a second inspection and determined that the trees have been kept healthy and thriving. 9. Road Mitigation Payment System The applicant or subsequent owner shall comply with the Road Mitigation Payment System (MPS), King County Code 14.75, by paying the required MPS fee and administration fee as determined by King County Department of Transportation. The applicant has an option to either. A. Pay the MPS fee at final short plat recording, or (B) pay the MPS fee at the time of building permit issuance. If the first option is chosen, the fee paid shall be the fee in effect at the time of short plat application and a note shall be placed on the face of the short plat that reads, "All fees required by King County code 14.75, Mitigation Payment System (MPS) have been paid." If the second option is chosen, the fee paid shall be the amount in effect as of the date of the building permit application. 10. Lots within this subdivision are subject to King County Code 21 A.43, which imposes impact fees to fund school system improvements needed to serve new development. As a condition of final approval, fifty percent (50%) of the impact fees due for the plat shall be assessed and collected immediately prior to recording, using the fee schedules in effect when the plat receives final approval. The balance of the assessed fee shall be allocated evenly to the dwelling units in the plat and shall be collected prior to building permit issuance. I I I I I I I I I I I I I I I I I I I 11. Suitable recreation space shall be provided consistent with the requirements of KCC 21A.14. a. A detailed recreation space plan shall be submitted for review and approval by DDES and King County Parks prior to or concurrent with the submittal of engineering plans. b. A performance bond for recreation space improvements shall be posted prior to recording of the plat. 12. Critical Areas: The proposed short subdivision shall comply with the Critical Areas Code as outlined in KCC 21 A.24. Impacts to critical areas shall be avoided where possible, and compensatory mitigation is required for approved adverse impacts. Preliminary short plat review has identified the following specific requirements that apply to this project. All other applicable requirements from KCC 21 A.24 shall also be addressed by the applicant. A. Wetland Category and Buffers (KCC 21A.24.325): This property contains part of a Category 11 wetland with fewer than 20 habitat points. The standard buffer width for this category of wetland is I 00 feet of unaltered native vegetation between the wetland and residential uses. Structures must honor an additional 15-foot building setback beyond the buffer. Within a currently undeveloped buffer, no development of any kind is usually allowed, including clearing, grading, or any other alteration of the existing vegetation. B. Critical Areas tract (KCC 21 A.24.180). The wetland and buffer on this property shall be placed in Critical Areas Tract to be shown on the engineering plans and final short plat. The Critical Areas Tract shall be held in an undivided interest by each owner of a building lot within the development, with this ownership interest passing with the ownership of the lot, or shall be held by an incorporated homeowner's association or other legal entity that ensures the ownership, maintenance and protection of the tract. C. A minimum building setback line of 15 feet shall be required from the edge of the buffer (KCC 21A.24.200). D. Permanent survey marking, and signs shall be installed prior to final short plat approval (KCC 21A.24.160). E. Temporary marking of critical areas and their buffers (for example, bright orange construction fencing) shall be placed on the site and shall remain in place until all construction activities are completed. F. The following note shall be shown on the final engineering plan and recorded plat: RESTRICTION FOR CRITICAL AREA TRACTS AND CRITICAL AREAS AND BUFFERS I I I I I I I I I I I I I I I I I I I Dedication of a critical area tract/critical area and buffer conveys to the public a beneficial interest in the land within the tract/critical area and buffer. This interest includes the preservation of native vegetation for all purposes that benefit the public health, safety and welfare, including control of surface water and erosion, maintenance of slope stability, and protection of plant and animal habitat. The critical area tract/critical area and buffer imposes upon all present and future owners and occupiers of the land subject to the tract/critical area and buffer the obligation, enforceable on behalf of the public by King County, to leave undisturbed all trees and other vegetation within the tract/critical area and buffer. The vegetation within the tract/critical area and buffer may not be cut, pruned, covered by fill, removed or damaged without approval in writing from the King County Department of Development and Environmental Services or its successor agency, unless otherwise provided by law. The common boundary between the tract/critical area and buffer and the area of development activity must be marked or otherwise flagged to the satisfaction of King County prior to any clearing, grading, building construction or other development activity on a lot subject to the critical area tract/critical area and buffer. The required marking or flagging shall remain in place until all development proposal activities in the vicinity of the critical area are completed. No building foundations are allowed beyond the required 15-foot building setback line, unless otherwise provided by law. G. No adverse impact to wetland hydrology shall result from this proposal. Engineering plans and calculations shall demonstrate that the pre-existing wetland hydrology will be maintained following construction of the development. H. Buffer reduction (21A.24.325.A.3.b): the buffer width will be reduced by 25 feet to a total of 75 feet in width, with a compensatory mitigation plan to remove off non-native plants and replace them with native vegetation to improve the degraded buffer condition. I. Future road access across the wetland and buffer to the Future Development Tract on the eastern portion of the property may be provided through a combination Access/Critical Areas Tract. If, in the future, access is provided to the Future Development Tract that does not require crossing the wetland, then that would preclude any road development on the Access/Critical Areas Tract. J. Compensatory mitigation (21A.24.340): A conceptual mitigation plan shall be provided for ODES review and approval along with engineering plan review for the buffer reduction proposal and Access/Critical Areas Tract. K. A performance bond or other financial guarantee will be required at the time of engineering plan approval to guarantee that the buffer reduction mitigation measures are installed according to the plan. Once the mitigation work is completed to DOES Environmental Scientist's satisfaction, the performance bond may be replaced by a I I I I I I I I I I I I I I I I I I I maintenance bond for the remainder of the three year monitoring period to guarantee the success of the mitigation. The applicant shall be responsible for the installation, maintenance and monitoring of any approved mitigation. The mitigation plan must be installed prior to final inspection of the plat. If, in the future, an access road is to be built across the wetland and buffers in the Access/Critical Areas Tract to the Future Development Tract on the eastern portion of the property, in conformance with the relevant Critical Areas Regulations of the local agency with jurisdiction, then the applicant at that time will be required to provide a detailed plan to mitigate for impacts from the wetland and buffer alteration for review and approved by the local agency with jurisdiction. Other Considerations A. Preliminary approval of this application does not limit the applicant's responsibility to obtain any required permit or license from the State or other regulatory body. This may include, but not limited to, obtaining a forest practice permit, an HPA permit, building permits, and other types of entitlements as necessitated by circumstances. B. Development of the subject property may require registration with the Washington State Department of Licensing, Real Estate Division. I I I I I I I I I I I I I I I I I I I ' ® King County Road Services Division Department of Transportation KSC-·rR-0222 201 South Jackson Street Seattle, WA 98104-3856 October 22, 2007 Robert H. Stevens, P.E. 14711 NE 29th Place, Suite 101 Bellevue WA 98007 · RE: Road Variance L07V0022 -Johnseine Short Plat Dear Mr. Stevens: Thank you for your application for a variance from the 1993 King County Road Standards (KCRS). You requested a variance from Section 2.10 of the KCRS concerning the intersection spacing for.the proposed access onto 148th Avenue SE. ·This road is classified as a collector arterial, and the.KCRS requires a minimum of300 feet of intersection spacing. The proposed location of the site access is 169 feet north of SE 123rd S.treet and is supported by · the Department of Development and Environmental Services. The access accommodates future development to the west. Moving the access to the north property line is not viable because a 15- . foot landscaping tract owned by a homeowner's association obstructs a potential half-street. I · approve a variance for reduced intersection spacing for the access road as proposed at 169 feet north of SE I 23rd Street. · This decision applies only to KCRS identified in the variance request. All other design requirements in the KCRS and other regulations, such as surface water management and zoning, must still be satisfied for a land use permit application. The applicant retains the rights and privileges afforded by King County Code and adopted Public Rules pertaining to road variance processing (KCC-14.42, PUT 10-2). This variance decision is valid for one year from date of letter unless an associated land use permit is pending or submitted within the one year period. In these cases, the variance decision is valid for the duration of the permit processing. I I I I I I I I I I I I I I I I I Robert H. Stevens, P .E. October 22, 2007 Page 2 A copy of staff's analysis, findings, and conclusions is enclosed. If you have any questions, please call Craig Comfort, Road Variance Engineer, Trnffic Engineering Section, at 206-263~6109. Sincerely, / c.~;l1t,•ffl -fli,,-.,,/;,/!tf~,_ Paulette Norman, P .E. County Road Engineer Enclosure cc:· , James Sanders, P.E., Development Engineer, Land Use Services Division (LUSD), Department of Development and Environmental Services (OPES) Pete Dye, P.E., Senior Engineer,LUSD, DOES Linda Dougherty, Division Director, Road Services Division (RSD), Department of Transportation (DOT) Matthew Nolan, P .E., County Traffic Engineer, Traffic Engineering Section, RSD, DOT Fatin Kara, P .E., Supervising Engineer, Traffic Engineering Section, RSD, DOT Kris Langley, Senior Engineer, Traffic Engineering Section, RSD, DOT Craig Comfort, P.E., Road Variance Engineer, Traffic Engineering Section, RSD, DOT I I I I I I I I I I I I I I I I I I 3. OFFSITE ANALYSIS: Upstream Tributary Area The area to be developed currently does not receive any upstream drainage. The wetland to the east of the site receives all of the drainage from the east and conveys it to the north and south of the site. Downstream Analysis RESOURCE REVIEW The site is located within the Lower Cedar River Drainage Basin which is within the Cedar River/Lake Washington Watershed. Resources listed in the KCSWDM were reviewed for existing/potential problems within the study area, i.e. the site and within !- mile of the site along the downstream drainage route. King County Soils Survey: The soils on site are Alderwood gravelly sandy loam. See Soils Map in Section 3A of this Report. I I I I I I I I I I I I I I I I I I I FEMAMaps: FEMA map dated May 16, 1995 numbered 53033C0982 F was reviewed. The site is not located within a flood plain. See Figure 3. / --- ~NTON \ ~ ~-11-..:c.i1e \ CITY OF RENTON B0088 ,n,v,i,r ,,..1 m,n, ---- t Figure 3. FEMA map numbered 53033C0982 F ION! X I Lu.,END m~==- _ .. :::-jgt:.-==-= -· =:-... ·:.::: .. ~ 11/iiiJ .:.:. =::;. ':'-= um -· f!.t:ffi7:.i.~ D '=·-=--··---· :..:...---- ~ !,sJ 11s] _:__ .. __ -· .-=:::. :::-.::-.. -..:: E ::::-:.:: :.:.:'.:: ":--=----·-=--=--=-.:::. ZONI X I I I I I I ' I I I I I I I I I I I I Sensitive Areas Folio iMAP: The King County iMAP was reviewed to confirm whether or not wetlands, streams or floodplain areas, erosion hazard areas, landslide hazard areas, or seismic hazard areas are located within the study area. A portion of a larger wetland, wetland number 23b, is located on the east side of the property. No other sensitive areas are located within the one mi le downstream study area. See Figure 4. -.l... i l I ,@1 --, / ·-· ; • Wetland 23lil,. I I I I ::: j \J ••• j I j \ I ·-· j ~1' ,I -j-j ..... I ·~ I • ·~1 !i1···j i! II I .i :: 1 1 !:·· i-- '1 . ' I ·. ' ••• , .;..:-· • l --· , r:· I ·1 ·-. ··· ....• :·· i I · I ·-· ·-· \'.~j--· L\ 'I / •'."" \'i'\ ' . • . End of snrdy Area. l ·-·-; • ..:.:-,· I +\""''. ·---, ,. __ ._ Ui~ ) ,~ ··-- / ·-· ·-· I~ ·-1 I ·-· ·-· t ·-· ·-· . --- Figure 4. Sensitive Areas iMAP x t.t:,untaln Peaks H,gh\'\1lY,. Stroots ~~ .. .,....,, tf:/ ~':. = SAO Stroum 1 °""' Ct.us.1~ /V er.n.,. ·: ~fflO'td /./ °""' ·J~ D Lu\os und Lor.go Rivors /./ Stroums D 100 Yeat Floodplain Im SAOWvtland ~ SAO Lundslide lffil SAO Coal Mino ~ SAO Seismk SAO Eros.ion I I I I I I ·I I I I I I I I I I I Drainage Complaints Maps: From the King County drainage complaint records on iMap there were four complaints found within the one mile downstream study area of the site. See Figure 5. ., .. OIIJ o::m '"' • ,,.. ... , mt 01 · oni) 0221 Figure 5. iMap Drainage Complaints ... ..... Researching the complaints, none were directly related to the storm water conveyance or the property being developed. Complaints D and B were over BCW membership and SWM fees. Complaint A was a dispute over a neighbor grading his property. The property has since been developed. Complaint C was from grey water discharge from a home. Complaints A and C follow. I I I I I I I M I I I I I I I I I I I Complaint A King County Complaints #1996=1771 #1996=0323 #1996=0157 I I I I I I I I I I I I I I I I I I I __.JAN. 29. 2007 3:55PM -KING CO. WLRO NO. 3165 P. 18/29 -- KING COUNlY SURFACE WATER MANAGEMENT DIVISION DRAINAGE INVESTIGATION REPORT Pago 1: INVl!STIGATION'Rl!QUEST . : Reoehled by: ,(.~ . . . Date: lo>,1V94". O~d by:.~ File No. • Reoslvsd from: DA"""' tA.u,i:L,A,n.1c W~11• J:ilfnt ptllnl)t for soannlt111). •• (Day) (Ew) NAME': ,X/t1{'? ; \k e,1 l<il:'1?:U\:P,Jg +( PH~S4-<y700 ADbRl!SS: 12..2 27. 148 n/ Ji.s:: ~,5" City J?....._rra«) Stato.!.oM. .... Z-lp~. _'z_f._;:is-_9 Loca~on cf probte,n, If different: RoportMI Prob/om: i),w-,· \S. C.c..~,·u e: fi,.._ \/,~ bt..f),:'77'-Y p..,...c9,,-r;': 77,,,:y /V1r?:-"t) To 5',tz t. f7,',!7/<' .5 ,fc,..=s (!-.,;r N-,, ,:;_or-:7.ii:::#,._,, c.,,.1,. A-~ r,r,.,.:r.~ fo /'~t-ti,.. _s;,.,..cP" f>""'4-Jrj./lC.,r /~v EC$, l.3'o·n, 'r?c~e"'.,,_..,.., .,.., .k,~.......,.,. Ti', f'1ff &,,,.,/(A;,v..o .... -r;;, ,;',,.;rlf "" ~ ,f,{.nLf;.,F>,.1'. Noerr./ ·./ ,::;;,-,,'-~ 4-r; r......-.11;,6,.r-r ;µ.;, ,!,r:.J<Wr ,..J f'1t,t .tf:,(.,..,.. .II .,(04'1> ......... 9 V/~1:--z.,.-r-~ J:)A-f/'_,./,A,,:.; oJ/'J'Tv T7Yi,cw<: . ~}--,,-rY. ··7?h,·· .!.--r ro rr,-.r fi,,<-r.o/ ~ ,/,t..:;-a-~~rc't> /7--'· ;"'k-< ·,4-r f.S 1(1,..., ,r/1,,F A:ec.,..,;:v~ he.. rrr.c-i,;,1,n;,e, ' leet/.: ·Cn.,t... [hJ,,, A,,e ro /.vv~uo~..v /c3 & U.-v Ou ... /,,"/<; Plat-name: ~~ 'J,i7>~. ";#::I ·LotN"o: Blook No: Other agencies Involved'; No.Field Investigation Needed rnnmrww: T-·Fftf'!ffllWllffflmfilffl&1¥i 11:we;rmscii:rrz flH. -;µs°'"-T ---R-Parcel No. KR>U Th.Bros: Now· . ·~0=1d~--- Basin_ Counoa Dist Chargo No: llESPONSEt Citizen normed, on~ by ....112.. phono letter Jo person ti-'~ ~"i'lj~ ,lo c.,(~,e ~-k -lo 't)De5. 6-cw. ~ G-k,,., le.. ...,....,~ _,,. .. :e .. 4,~ -fl.;• ~ 0/SPOSfT/ON: Tumod to · --on -by OR: No further action recommended baoause: ..E Lead agency has boon notffled: b D65 5i~ ~~flill NI _ Problem has been corrected N-~ t/JC~ . · _ o problem s been entffl . _ r or lnvesilgatloria dressn problem: -:--Pr!vo.te problem ~ NOAP wl/1 not oonsfdar bscauso: ee, PH•# · _ Water originates onslta and/or on neighboring 11a,rceJ _. Location Is outsldo SWM Serv':3,;~· . _. Olhor (Specify): DA.TE CLOSED: ...i.f..._;.Ql;.J.f:.._ by: ..::f!::;/ If F,)-.vf:;> VtrS I I I I I I I I I I I I I I I I I I I ....... ;A,. 19. 1007 3:55PM ___ KING CO. WLRO.--~--····- Kln&Coonty Department otNaturalResou«:c:S ' Surface Water Management DRAJNAGE INVESTIGATION REPORT· ll'JEt.l) INYJtSTlQ,'\TION mA NOJ'°'l171 NAM!k JOHN KA.t.lZLAIUOJI JWOJWN: i:ui1 14ml AW a 1'11014 "'"'100 MAllfTB!!ANCI! 4 ___ _NO. Jl61_P. 19/19 _, """· _.,""'ell 'l'HO'MAS PAOB mn DATB 104J.,915 INrrlALB DCD DETAILS OF INVESTIGATION: Dave Kauzlarich Is the son of the property ownera. Dave Is cnncerned thnt tho proper!)' hat b .. n damage~ with all the activity al the nunery lo the ,outh and the nelahbon to tho north ofthem. A wotlRlld now emir.on the baclulde of the proper!)'. Dave feels with ell thuetlvlty of tho · other propotles they. are now tho duinpl•R around for au the surface water nows. I walked the pasture on the bacl<Slde of the proper!)' and found the wetland Dave was talking about hut could not find a direct now patb offhe water from the nur,017' or the north property. It appear, the water ponds on the Kauilarich's ·~ property thon fiow1 to the north. I will check the iensltlve areas maps to flod out what ls located on the backside of this propety. ,SKETCH: ' Pil.LAIU!A ............................................................................................... I I ! i \··"· .......... ~ ................................................................................................................... . ! { NURSERY '--·············-·-····-····-··-·····-----········ ·····--················-·· 148TII A VB SB I I I I I I I I I I I I I I I I I I I JAN. 29. 2007 ):54PM ----. KING CO. WLRD NO. 3165 ;-. 13h9i, J --KING COUNTY SURFACE WATER MANAGEMENT OIVISION , DRAINAGE INVESTIGATION REPORT · · (i·.,, ~--• ,dnJAf Page 1: INVESTIGATION REQUEST . Type C,., · mm ouid/ com,A;;,; · ~ 'Rtcelved'by: /i'!e/( 71,ofYlpson.·•11ne) Dale:,. W!/Jte ___ DK'd by:' ,,_, ___ FIio N~ •. "9'~ -3q13 __ , lle,:s/vsd from: . ~ (Pln.H print plalril)' fer tcannln~), (Day) (Ev•) NAME, 77aa 1;)11/ton PHDN~ f}([;)-O&J _··--- ADDRESS: /gdd 7 -/ij/lfh /It/(', fit. City. ~ ;,a« __ Zlp f.f,?j Location or problem, If different: -·--·------·----------------------__ :......---'------. ----------- R1tportsd Prob/om: · · / · !,/e,9h6or d,911'ti9 /17 cri-:e,,f w1"1/J mdrlioe, #Jinks /f ,:S, a f)/'Oledecl (Lie/land. No fl-/o . ' She Plat r.1.1me: · Lot No: Bloclc No: · Othar ai:;,eno!u lnvotv,d: No Fi;:fd lnvestig1tlon Netdid __ ._ ___ s,_,_1•_/Z/q. _ _,__ Co~:~:~'.s_i_/._:.2__ .~C:_h:••~g:_e :.:_N:o'====::: RESPONSE: Cltlzen notified on ___ by _ phone_ letter _ ln person DISPOSITION,: Tl.irn-.d 10_ on ____ by __ _ OP.: No further action reeornmendad bee!! Leed agency has beein notified: = Probletr'I tJas been corrected: -::"'N7o 7pr==o"'bl;-em=h-as""""'be"e-cn71d'"o""nt"'m~,d7 .----P"r~lo7r""ln-ve-,"lig-a""tl-oa-.a:-:dndc:,o"c,s::-o-,-=p=robh _ Privert1 problem . NDAP will not ~onsldsr b,ccu,e: _ Water or1glnates onslle and/or on neighboring parcel Locallon Is outside SWM Service Area. s., Fil•#• ____ _ _ Other (Specify): DATE CLOSED: ....!L../~ 'J(. by: ..::fll/ . SGG'' <Jt,-(')/$"7 i I I I I I I I I I I I I I I I I I -JAN. 19. 1007 3:54PM -KING CO. WLRO -NO. 3165 P. 11/19 KING COUNTY SURFACE WATER MANAGEMENT DIVISION DRAINAGE INVESTIGATION REPORT - Page l: INVESilGATION REQUEST ' t Typo c_. R,c,~ed bY:,,/'.leO ,---------·· D"•JJ i jn,cm?~-Filo No .. q lo-15 L. Received from:· "'R 1ck:. i1\ 0 m Y., &OrJ(PJ•an prlnl pl•lnly for 1C&nnlng). {Day) (e11,) ..,1...c1.1..:N"'"''--. _,W""--""'"-' .wi:P...:N_,_ __ ~---· __ PHoNe zc:;. is -D 19 3=· __ ADDREss.: __ ..:·1..:z..:2::...::2.:..:i,..:.:·_...:·.,_1 '-1-'-"'8:...· fl<l_.----'l'i"\/===e::.....:,;;:..:r:=--c11y. R t..r-JT!>N s1a,•-. _· 21/1'if()'71 NAME: Location of problem, if different: Rt1port11d Prohlem: N~hbo,.,. "is. h <'i.ct._ hoe. . 1"-.:1 s uJ,a,y(~. ' ~j '.'.'} 11'1 :J · IN 1N. IS be); ,eveo/ .f.o DISPOSITION,: Turned to ___ on-----by __ _ OR: No fut1her ac1ion recofnmended.~ect LLead es;eocy has be,n riolltl&d: _.!,])~/)~cf3",.;..L,_,--'S,~,.,.,c,t,~"'NV~~C"=----~~~~==--c:.='c==cc, _ Problem ha~ been corrected, · _ No problem has been loenlified. Prior lnvutlgatlon e.ddresses 'Probl -So,~,.~----- Prlvere problem -NDAP wlll not consider because: -· Water originates onslft e.nd/or On neighboring parcel = Locatlo~ ~· outsldo SWM Sep. _ Oth,r (Specify): DATE CLOSED:_.!!_; ,;l'J1_2i{ by: ,(r{)l}/7e,-;}G,el)G I I I I KING CO. WLRD .. JAN. 29. 2007, 3:54PM ·--~-~-------- complaint 96-0167 Walton, Tina Investigated by Doug Dobkins on 2·21-96 NO. 3165 P. 12/29 I met with Mr. Walton onslla to dlsouss his concerns with the work being done on the nursery property to the south. According to Mr. Walton the nursery has been clearing land that could be considered a wetland. I walked the back property line of Mr. Walton's property and discovered that he else has doni, some work In the wetland to install a fence. Mr. Walton cleared In the wetland end disturbed e small stream. I told .Mr. Walton that h& needs to talk to ODES Grading section about a permit to do this work end to stop work In the wetland. I triad to access the property of the nursery to the south but was unsuccessful because they were closed. The nursery eppears to have encroached the wetland with Its clearing. I suggest sending this complaint to ODES Grading section for their investigation. k1 . ' .,~-I:' ___ _jl1.-+------·---------- ,.... i:1 . 1 ® ' ~, •. { ~~----i-' ---------= --~~---~E!' ., .-I!--"·· .I I . . ~ .. ~ I @lJ ._,.J a ~ ·--·---·---_____ . ____ §1 ... 2::L.fll'J~. • • t" • . ~ .. • I I I I I I I I I Complaint C I King County Complaint I #1998=534 I I I I I I , I I I I I I I I I I I I I I I I I I I I I ,. FEB. 9. 200) 12: J4PM,w ':K~O. WLRD .. t<"-"1' J.,Al\JJ .tu;,;UUK<;£S·JJ~· 33)) ·kl f,/\ .e.· ~ DRAINAGE INVESTIGATION REPORT . ~ Page I: INVES!TOATION 11£Ql1EST . T)'pe ~ . PROBLEM!/lJas6{{11frv m{5'&?#U . · J..J · R1;ce1vEpay· .,5be (?/qAo ' Date· $'.-/o-'i'r OK'dby: J;>(l.\A.. Fru;No.· 9'/ ffJ1. · ' Received from: , · . · · 1 //./ c- • (Day) ~ (Eve) 1..-..-1 NA~~: '-'3ba11j: ~ ~ Oq~~c~HONE c;JBS-;l.'{</'3 ADDRESS: . ..?, ,ii ... /ji ~City &(?-,,( State~ Zip fY1%:( Location of problem, if dilfererit: ~. .. To bE COMPLETED BY CO~f PLAlN_T ~l(OGRAl\1 STAFF .. .:, .. , . :: ........ ·, ~ ·•·.•· • B~in ,LC,1' Council District .i2... Kroll~· Th.Bros: New t:$?J2,, Old <3505 Charge No.'-------- RESPONSE: Citiz(i:n notified on -----by: --. phon~ __ lett~r __ in'person DISPOSJl'ION: · 1ed:,-,--,.-,-,-~---,-----,----------"'t.C='•:::•n_::ha.s::_:h:::co~n~coec""""" _ No probJ~ has been identified. _ Prior investigation a~dresses problem: ra,~ St1F1u# --- Priv,ate problem· NDAP will not consider because: __ Water originates onsite and/or On neighboring parcel. __ Location is outside WLRD ~c:rvi*ca~ __ Other (Specify): )ATE CLOSED: /2 120· 10{ lly:~i( · . . . ;°~t91(}J,e~ I I I I I I I • I I II I] II I I I I I FEB. 9. 2007 12:34PM Kl NG CO, WLRD ·---·--·--' l>ntc: Mnnih 26, 2001 Dato oflnvoulgatJon: l>occmbor 14111 1 2000 FM: Oary-.Paul Reinke RE: WQ Evaluation for Complnint # 98-0534 Shnyla and Casoy Cox 13224 ~ 144" Avenue SB RcntOJJ., WA. 98055 l>ay ~CONNBCTBD (tho Cox fo.mily bu moved on) O'Mier~-768-1062 llwllw NO. 3377 P. 3 I havo been cllockfng 1h13 rfto whonovcr l ~.in tho ma to 11cc ifl cou1d f"md llll)' evidence of tho problems tha Cox's ha.vo mentioned. I have not found II.DY evidence of hou10 pipos cxitlni to the stream or any otbor part of tho property. The Cox's have mbvod cm and there is a now family In the house now. Th.oy had no idee. of what r was 'lnlldng about. I did contact tho oWnOr (Roget Brendan) of tho property and.he ,aid tho previous tcnsuts hnd ID.lldo the ntosal conaection. 'I'ht former tenants ero now 1onc aod the illosaI pipo bu been plugged up. Numerous visits to tho lfto confirm this is no long« a problem. QptioQ! and DhSJ1ssfon ' ~ I stated, I haven't found any ovidenco of tho problLmt in about 8 spot cheob on Ibo place. The overllll condidon of tho property b poor IID.d thCic U Jotsofjunk.1ywe about but nothing thtJ.twoutd seem to ~t water quality. ProPru:sd SoluHnn I Juggest we close the C!ompllU!lt. r •• I I I I I I I I I I I I I I I I I I I FIELD INVESTIGATION The downstream field investigation was conducted on January 30th, 2007. The weather was cool, 55 degrees and sunny. There had been no precipitation in over a week. The downstream analysis begins at the site (point A). See Downstream Analysis Existing Course Figure 6 on the following pages. The drainage flows through a vegetated open channel south for approximately 129 ft in front of the site (point B). Flow then enters a 12" concrete pipe flowing approximately 22 ft under the driveway of the neighboring lot (point C). Flow exits the pipe into approximately 121 ft of vegetated channel in front of 12232 and 12240 1481h Avenue SE (point D). Flow continues approximately 69 ft through a 12" concrete pipe under the driveways of 12240 and 12250 i 48'h Avenue SE (point E). Leaving the pipe, flow continues through approximately 79 ft of vegetated channel in front of 12250 and 12260 1481h Avenue SE (point F). Continuing flowing south, flow enters approximately 19 ft of 12" concrete pipe under the driveway of 12260 148 1h Avenue SE (point G). Flow discharges from the pipe into approximately 54 ft of vegetated channel (point H). 12" CMP collects flow from the channel and directs flow approximately 24 ft (point I). Flow leaves the CMP falling into the catch basin at the NE corner of the 1481h Avenue SE and SE 124 1h Street intersection (point J). Flow exits the catch basin to the east through approximately 21 ft of CPEP into a catch basin on SE 1241h Street (point K). Flow is redirected from the west to the southwestern direction at the catch basin (point L). Leaving the catch basin through approximately 43 ft 15" CPEP flow continues in the southwestern direction (point M). A catch basin on the SE corner of the 148 1h Avenue SE and SE 1241h Street receives the flow from the pipe (point N). A 15" CPEP takes the flow approximately 34 ft under the sidewalk improvements and discharges into a vegetated channel (point 0). The open vegetated channel takes the flow approximately 75 ft south in front of 12414 1481h Avenue SE. (point P). From the channel, the flow is taken through approximately 71 ft of 12" CPEP (point Q). The CPEP transitions into approximately 69 ft of concrete pipe (point R). The flow exits the concrete pipe into a concrete structure (point S). Leaving the concrete structure through a 12" concrete pire, the flow continues approximately 224 ft south in front of 12430, 12438, and 12444 1481 Avenue SE. (point T). The flow exits the concrete pipe into a concrete structure (point U). Flow continues south through 12" concrete pipe for approximately 34 ft under the driveway of 12610 1481h Avenue SE (point V). Flow exits the pipe into the channel in front of 12610 l 48'h Avenue SE to continue flowing south for approximately 115 ft (point W). Flow leaves the channel through a trash rack into 18" CPEP for approximately 14 ft (point X). Flow exits the pipe into a catch basin (point Y). Flow exits the catch basin through approximately 84 ft of 18" CPEP (point Z). Flow exits the CPEP into a catch basin (point AA). Leaving the catch basin, flow continues for approximately 139' through 18" CPEP along 1481h Avenue SE (point AB). Flow exits the pipe into a catch basin (point AC). From the catch basin, flow continues approximately 95 ft south through 18" CPEP (point AD). The 18" CPEP empties into a catch basin at the end of the Y. mile study area end (point AE). No drainage, erosion, or sediment buildup problems were found during the field investigation. I I I I I I I I I I I I I I I I I I I LEGEND 0 OPEN CHANNEL 0CONCRETE 0CMP 0 CPEP cCATCH BASIN ccoNCRETESTRUCTURE u I I I I I I I I I I ,/ r • ; ' :.~-.. j I l r,. LEGEND 0 OPEN CHANNEL 0CONCRETE UcMP OcPEP acATCH BASIN acoNCRETESTRUCTURE Figure 6. Downstream Analysis Existing Course Continued I E I I I I I I I I I I I I I I I 4. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN: A. Hydraulic Analysis The drainage analysis was modeled using the King County Runoff Time Series software. The onsite soils are Alderwood (AgC), KCRTS group Till per the Soils Map attached on the following pages. The site is located in the Landsburg rainfall region with a location scale factor of0.85. EXISTING CONDITIONS EXISTING BASIN BOUNDARY The existing drainage basin boundary will include the property area, 197,974 square feet, less Tract D which will remain undisturbed, 90,532 square feet, less Tract E which is a future development area, 45,000 square feet, plus the 1481h Avenue SE frontage area between the existing edge of pavement and the right-of-way, 3,801 square feet. Existing ground cover will be modeled as Till-Forest. The following information was used for generating time series and flow frequencies. EXISTING CONDITIONS Total Area= 66,243 sq. ft. or l.52 acres (06083ex) GROUND COVER AREA(acre) Till-Forest 1.52 I I I I I I _An I I I I I I I I I I I Figure 7. Soils Map I (RENTON QUAI: 1 680 000 FE ET 122°07'30" 47°?0' --+--~ .. .-.: 2713011 I I I I I I I I I I I I I I I I I 3.2.2 KCRTS/RUNOFF FILES METHOD-GENERATING TIME SERIES "''''i'"._·~· ... -• -• -.•. ~-' ·'. -t_'."• ') ~ ·•~ '• • '. '-~ • . ., • ' • _ · _" •';:) • -~ • •• ~ .. , "} t· f -0 ":'' ' 7_..:.,;,,.;r. __ ._; ~.--''J:'...; '· ·,·_.~.: •"•• (;-i'i7lix~hi<;)1fi:i}' iEQUtYA'.l;EF.t,~, ~~TWEEN scs:~011-:;i:vnE~'ANP, KGJl'ts'so}f:fYPES: ,.fl t-~····f·.-..... ~_,:,;}, • .. r •. l,: ·r,. \, ;'1:~'.-.-......... .,,,,"c.,· l, /. ~-...... i)r.:,-).r-..'.<11.,.._·t>.t·.~--·· -~----, .. --~u:-.. :0.~-"""·""'·'-·' SCS Soil Type scs KCRTS Soil Notes Hydrologic Group Soil Group ( Alderwood (AgB, Age, AgD) e Till J Arenis, Alcterwood 1V1atenal (AmB, Ame) e Till Arents, Everett Material (An) B Oulwash 1 Beausite (Bee, BeD, BeF) e Till 2 Bellingham (Bh) D Till 3 Briscot (Br) D Till 3 Buckley (Bu) D Till 4 Earlmont (Ea) D Till 3 Edgewick (Ed) e Till 3 Everett (EvB, Eve, EvD, Ewe) NB Outwash 1 Indianola (lne, lnA, lnD) A Outwash 1 Kitsap (KpB, Kpe, KpD) e Till Klaus (Kse) e Outwash 1 Neilton (Nee) A Outwash 1 Newberg (Ng) B Till 3 Nooksack (Nk) e Till 3 Norma (No) D Till 3 Orcas (Or) D Wetland Oridia (Os) D Till 3 Ovall (Ove, OvD, OvF) e Till 2 Pilchuck (Pc) e Till 3 Puget (Pu) D Till 3 Puyallup (Py) B Till 3 Ragnar (Rae, RaD, Rae, RaE) B Outwash 1 Renton (Re) D Till 3 Sala! (Sa) e Till 3 Sammamish (Sh) D Till 3 Seattle (Sk) D Wetland Shalcar (Sm) D Till 3 Si (Sn) e Till 3 Snohomish (So, Sr) D Till 3 Sultan (Su) e Till 3 Tukwila (Tu) D Till 3 Woodinville (Wo) D Till 3 Notes: 1. Where outwash soils are saturated or underlain at shallow depth (<5 feet) by glacial till, they should be treated as till soils. 2. These are bedrock soils, but calibration of HSPF by King County DNRP shows bedrock soils to have similar hydrologic response to till soils. 3. These are alluvial soils, some of which are underlain by glacial till or have a seasonally high water !able. In the absence of detailed study, these soils should be treated as till soils. 4. Buckley soils are formed on the low-permeability Osceola mudflow. Hydrologic response is assumed to be similar to that of till soils. 2005 Surface Water Design Manual 1/24/2005 3-25 I I I I I I I I I I I I I I I I I I I 6.4.1 WETPONDS -BASIC AND LARGE-METHODS OF ANALYSIS FIGURE 6.4.1.A PRECIPITATION FOR MEAN ANNUAL STORM IN INCHES (FEET) ST 1.0 ST 1.1 0.54" (0.045') 1., .,,. I Incorporated Area ....c=:, River/Lake Major Road 0.47" (0.039') 0.47" (0.039') NOTE: Areas east of the easternmost isopfuvial should use 0.65 inches unless ralnfall data ls available for the location of interest 24 The mean annual storm Is a conceptual storm found by dividing the annual precipitation by the total number ot storm events per year :LUU5 SU.rface Water Design Manual 6-71 LA 1,0 LA 1.2 KING co~NTT I/24/2005 I fi Flow Frequency Analysis LogPearson III Coefficients Time Series File:06083ex.tsf Mean--1. 272 StdDev-0.226 I Project Location:Landsburg Skew-0.101 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob I (CFS) (CFS) Period 0.061 21 2/16/49 21:00 0.170 1 89.50 0. 989 0.144 3 3/03/50 16:00 0.165 2 32 .13 0. 969 I 0.120 4 2/09/51 18:00 0.144 3 19.58 0.949 0.044 33 1/30/52 8:00 0.120 4 14.08 0.929 0.035 40 1/18/53 19:00 0.103 5 10.99 0.909 0.047 28 1/06/54 6:00 0.102 6 9.01 0.889 I 0.055 24 2/07/55 22:00 0.096 7 7. 64 0.869 0.049 25 12/11/55 16:00 0.091 8 6.63 0.849 0.044 31 12/09/56 17:00 0.091 9 5.86 0.829 0.035 41 1/17/58 7:00 0.086 10 5.24 0.809 I 0.042 36 1/24/59 15:00 0.077 11 4.75 0.789 0.063 19 11/21/59 2:00 0.075 12 4.34 0.769 0.047 29 11/20/60 15:00 0.073 13 3.99 0.749 I 0.023 47 12/17/61 7:00 o. 071 14 3.70 0. 729 0.043 34 2/03/63 3:00 0. 067 15 3.44 0.709 0.073 13 6/18/64 17:00 0.066 16 3.22 0.690 0.059 22 1/29/65 7:00 0.064 17 3.03 0.670 I 0.020 49 1/05/66 16:00 0.064 18 2.85 0.650 0.034 42 12/13/66 11: 00 0.063 19 2.70 0.630 0. 046 30 6/03/68 6:00 0.061 20 2.56 0.610 I 0.075 12 6/23/69 21:00 0.061 21 2.44 0.590 0.034 43 12/13/69 21:00 0.059 22 2.32 0.570 0.066 16 1/09/71 0:00 0.057 23 2.22 0.550 0.077 11 2/28/72 16:00 0.055 24 2 .13 0.530 I 0.036 39 1/13/73 5:00 0.049 25 2.04 0.510 0.032 44 2/19/74 0:00 0.049 26 1. 96 0.490 0.091 8 12/27/74 2:00 0.048 27 1. 89 0.470 0.061 20 12/02/75 21:00 0.047 28 1. 82 0.450 I 0.015 50 3/03/77 2:00 0.047 29 1. 75 0. 430 0.064 18 12/02/77 23:00 0.046 30 1. 70 0.410 0.039 38 2/06/79 19:00 0.044 31 1. 64 0.390 I 0. 067 15 12/15/79 12:00 0.044 32 1. 59 0.370 0.086 10 11/21/80 11: 00 0.044 33 1. 54 0.350 0.049 26 1/23/82 20:00 0.043 34 1. 49 0.330 0.071 14 1/05/83 10:00 0.042 35 1. 45 0.310 I 0.102 6 1/24/84 16:00 0.042 36 1. 41 0.291 0.031 45 11/01/84 23:00 0.039 37 1. 37 0.271 0.057 23 1/18/86 21:00 0.039 38 1. 33 0.251 I 0. 096 7 11/24/86 5:00 0.036 39 1. 30 0.231 0.048 27 3/27/88 11: 00 0.035 40 1. 27 0 .211 0.039 37 1/09/89 22:00 0.035 41 1. 24 0.191 0.103 5 1/09/90 7:00 0.034 42 1. 21 0.171 I 0.091 9 11/24 /90 14: 00 0.034 43 1.18 0.151 0.044 32 4/18/92 18:00 0.032 44 1.15 0.131 0.042 35 3/23/93 0:00 0.031 45 1.12 0 .111 0.023 48 3/03/94 3:00 0.031 46 1.10 0.091 I 0.064 17 2/19/95 18:00 0.023 47 1. 08 0.071 0.165 2 2/09/96 0:00 0.023 48 1. 05 0.051 0.170 1 9/17/97 11: 00 0.020 49 1. 03 0.031 I 0.031 46 10/30/97 7:00 0.015 50 1. 01 o. 011 06083ex.PKS Page I of2 I I I Computed Peaks 0.186 100.00 0.990 Computed Peaks 0 .160 50.00 0. 980 I Computed Peaks 0.135 25.00 0. 960 Computed Peaks 0.105 10.00 0.900 Computed Peaks 0.099 8.00 0.875 Computed Peaks 0.082 5.00 0.800 I Computed Peaks 0.053 2.00 0.500 Computed Peaks 0.036 1. 30 0.231 I I I I I I I I I I I I I I 06083ex.PKS Page 2 of2 I v)'o' \') ,, -·1;...._r~ P'.-'~ ----, '· Ct1 T"'P:.,: RI , '5, 3 '" ,.-,, - ' "l ' ------, •II:= • :: J ~ ~ .n_ ,~ s ;_£,- HII Ill ,. \. A/~ ~ 0 ,J / ' I -~,, 11---,1: I ;;,;. ~,~~~ . ~ I I I ' "' ~\:=-=-=--=~"'"'~=-=r-=-=--~ Ii mAcr c'\ ) I .Ii i 2" IE N 506.64 ". ..: I ~ ! 5 ,• IE SW 506.74 J : ... ll &C ''---.d;{'. • I \ -------~~. ~\) ~-" " . . ' --------;''" I I 1('" \'-~~, I" I I 1 .. 30' 30j ------t! ~ .. ~( 1' ! 12 ~ '¢J -~, -I i r· .1 , ' ~ OJI I "'--C: .. .Et..\Ql.li 0 , R"::: :-,1 () 6~ "'-JI I '-.... ,, ' ~- I I I i I 11 -1+1 L_ 1 K' SEWER _Lil_ .1-EASEMJJ:JT (// ' \ \ \ \ ) ! \ I "'/.9 \---~ _l v~ ~ "' \ /) --- "'\ ( ~ d . ....._ = EXISTING BASIN = BOUNDARY (1.52 AC) __ DEVELOPED BASIN BOUNDARY (1.52 AC) DATE ! l SCALE: 1" = 40' 0 10 20 '40 ro/~ ,,,.,,..,,..,,_ ... , :, ·-? • .......... Wa,nlnp,n 98007 \.... --_/ · ,_ 42$.N.S.7877 ~ 425.885.7963 ~ DESIGN ENGINEERING , PLANNING· SURVEYING SITE PLAN PLEASANT PATH APRIL 2008 DESIGNED NWO DRAWN NWO PROJECT NUMBER 06083 I I I I I I I I I I I I I I I I I I I DEVELOPED CONDITIONS The proposed project includes constructing eight single-family residential Jots with associated roadways and utilities. Access to the site will be via the onsite road accessing 148th Avenue NE. Half-street improvements on J4gth Avenue SE along the property's western frontage , including pavement widening and installation of curb, gutter, and sidewalk, will be completed as part of the subject project. FLOW CONTROL BMP REQUIREMENTS Per Section 1.2.3.3 in the 2005 KCSWDM, projects subject to Core Requirement #3 must apply flow control BMPs to impervious surfaces as directed by this section to either supplement the flow mitigation provided by required flow control facilities or provide flow mitigation where flow control facilities are not required. Flow control BMPs must be selected and applied according to the basic requirements, procedures, and provisions detailed in Section 5 .2 and the design specifications for each BMP in Appendix C, Section C.2. This project is implementing the flow control BMPs with the development of the site. The implementing of flow control BMPs during site development is optional and can be deferred until a permit is obtained for construction on each Jot. By implementing the flow control BMPs during the development of the project, all or some of the flow control BMPs can be moved outside of the individual Jots themselves and placed in designated tracts within the development. Implementation during the development process not only allows for more options in placement of flow control BMPs, but also lets the development take credit for these flow control BMPs when sizing the onsite detention/water quality system. Per the Small Lot Requirements, Jots less than 11,000 square feet, each lot must connect to the local drainage system with a perforated pipe connection, and must apply flow control BMPs to mitigate runoff from an impervious area equal to 10% of the lot area. These BMPs can either be applied individually on each lot or if done during development, the flow control BMPs can be distributed throughout the site. For the subject project, flow control BMPs will be applied during the development of the site. Each lot will connect to the onsite detention/water quality facility through a perforated pipe connection. A portion of the I 0% of mitigation for every Jot will be done through the use of permeable pavement on Tract C, a joint use driveway serving lot 6 and Jot 7. The remaining mitigation will be accomplished with permeable pavement on each lot. The area needed to be mitigated for on the site is broken down below. AREA ON SITE REOUIRING FLOW CONTROL BMPS Total Area of Lots on Site 41,236sqft Percent of Lot Area to be Mitigated 10% Total Area to be Mitie:ated for on Site 4,124 SQ ft I I I I I I I I I I I I I I I I I I I Mitigating for the impervious surface on Tract C with the flow control BMP option of permeable pavement accounts for 1,145 square feet of the 4,124 square feet of impervious surface needing mitigation on the site. The remaining 2,979 square feet will be broken up equally between all eight lots. The breakdown can be seen below. INDIVIDUAL LOT FLOW CONTROL BMP MITIGATION Total Area to be Mitigated for on Site 4,124sqft Area Mitigated for with Permeable Pavement on Tract C 1,145 sq ft Remaining Impervious Surface Area Needing Mitigation 2,979 SQ ft Area of Impervious Surface Mitieation Required Per Lot 372 sq ft The 3 72 square feet of impervious surfaces requiring mitigation on each lot will be accomplished by the use ofa minimum of372 square feet of permeable pavement on each lot. The permeable pavement will not be constructed during the development of the project, but a declaration of covenant and a grant of easement will be placed on each lot to ensure the flow control BMPs are constructed with lot improvements. The covenant will provide notice to the future lot owner that they are responsible to install a minimum of 372 square feet of permeable pavement on the lot prior to final inspection approval of constructed lot improvements. Alternative BMPs that provide equivalent performance may be proposed at the time of permit application for proposed lot improvements. In any case, a revise covenant will needed to be recorded to reflect the final approved BMPs and site improvement plans. The easement over each lot will grant King County or its successor the right to enter the property at reasonable times for purposes of inspecting the flow control BMP and to perform any corrective maintenance, repair, restoration, or mitigation work on the flow control BMP that have not been performed by the property owner within a reasonable time set by Department of Natural Resources and Parks, and to charge the property owner for the cost of any maintenance, repair, restoration, or mitigation work performed by King County. Flow Control BMP Sizing Credit Credit will be given to the sizing of the onsite detention and water quality facility as stated in Table 5.2.2A (p. 5-12). For the subject project the flow control BMPs that will be implemented are "Permeable Pavement (non-grassed)" and "Perforated Pipe Connection". Per Table 5.2.2A "Permeable Pavement (non-grassed)" can be modeled as 50% impervious and 50% pervious and no facility sizing credit is given for the use of "Perforated Pipe Connection" I I I I I I I I I I I I I I I I I I I DEVELOPED BASIN BOUNDARY The developed drainage basin boundary will include the property area, 197,974 square feet, less Tract D which will remain undisturbed, 90,532 square feet, less Tract E which is a future development area, 45,000 square feet, plus proposed improvements and existing pavement along 148th Avenue SE that will be captured within the proposed conveyance system, 3,801 square feet. The impervious and pervious areas break down within the right of ways and tracts are tabulated on the following page. The impervious and pervious areas for each lot was calculated per section 3.2.2.1 of the 2005 KCSWDM. Per this section, the lots can either be calculated by taking an average of 4,000 square feet of impervious surfaces per site, or by calculating the maximum impervious surfaces allowed per the zoning of the site. Option with the lowest impervious area should be used. Our site is zoned R-4. This allows for maximum impervious coverage of 55%. There are 41,236 square feet of proposed lots on the site. With the maximum impervious coverage of 55% there would be a total of 22,680 square feet of impervious surfaces on the lots. Using the 4,000 square feet of impervious surfaces per lot and having eight lots on the site that would be 32,000 square feet of impervious area. Taking the lower value, 22,680 square feet of impervious surface will be accounted for on the site. With the use of flow control BMPs, 50% of the impervious surface on Tract C will be accounted for as pervious and 50% of the 2,979 square feet of pervious pavement required on the lots will be considered pervious. The breakdown of impervious surfaces on the subject project can be seen on the following page. I I I I I I I I I I I I I I I I I I I DEVELOPED CONDITIONS TRIBUTARY TO VAULT Total Area= 66,243 sq. ft. or 1.52 acres AREA DESIGNATION AREA Area Adjusted for Flow (sq. ft.) Control BMP Credit 148"' AVE SE R/W 3,801 3,801 Existing Impervious 1,395 1,395 Proposed Impervious 2,202 2,202 Pervious 203 203 ENTRY ROAD R/W 8,768 8,768 Impervious 8,768 8,768 TRACT A 8,925 8,925 Pervious 8,925 8,925 TRACTB 2,087 2,087 Impervious 1811 1811 Pervious 276 276 TRACTC 1,495 1,495 Impervious 1,145 573 Pervious 350 922 LOTS 41,236 41,236 Impervious 22,680 21,190 Pervious 18,556 20,046 The following information was used for generating time series and flow frequencies. DEVELOPED CONDITIONS TRIBUTARY TO VAULT (06083dev) Total Area= 1.52 acres GROUND COVER AREA(sq ft) AREA(acre) Till-Grass (Landscaping) 30,944 0.70 Impervious 35,367 0.82 I I I I I I I I I I I I I I I I I I I DEVELOPMENT STANDARDS -DENSITY AND DIMENSIONS 21A.12.010 -21A.12.030 21A.12.010 Purpose. The purpose of this chapter is to establish basic dimensional standards for development relative to residential density and as well as specific rules for general application. The standards and rules are established to provide flexibility in project design, and maintain privacy between adjacent uses. (Ord. 10870 § 338, 1993). 21A.12.020 Interpretation of tables. A. K.C.C. 21A.12.030 and 21A.12.040 contain general density and dimension standards for the various zones and limitations specific to a particular zone(s). Additional rules, exceptions, and methodologies are set forth in K.C.C. 21A.12.050 through 21A.12.210. B. The density and dimension tables are arranged in a matrix format on two separate tables and are delineated into two general land use categories: 1. Residential; and 2. Resource and Commercial/Industrial. C. Development standards are listed down the left side of both tables, and the zones are listed at the top. The matrix cells contain the minimum dimensional requirements of the zone. The parenthetical numbers in the matrix identify specific requirements applicable either to a specific use or zone. A blank box indicates that there are no specific requirements. If more than one standard appears in a cell, each standard will be subject to any applicable parenthetical footnote following the standard. (Ord. 10870 § 339, 1993). 21A.12.030 Densities and dimensions -residential zones. A Densities and dimensions residential zones - RESIDENTIAL ' '"""' URBAN URBAN 0 "· RESIDENTIAi.. ' SERVE ' ' STANDARDS = .... ='" =M "' R-1(17) ., .. •• R-12 R-11 R·24 ·~ ,., BaH Dan•lty: ,., 0, o., 0.05 o., ' • • • " " ~ .. Dwelling dulac du/ac dulac du/;ic dulac 0,K du/ac dWac du/ac dWac awK du/ac 'WK Unit/Ac,.. (21) ,., "' Ma,lmum De,tfllty: ... • • " " " " " Dwelling Un!UAcre du/ac du/ac du/ac du/ac du/ac diilac du/ac du/ac ,, 1201 '"' Minimum O.n,lty; '" '" '" '" '" '" '" '" {12) (12) (12) (18) (18) (18) (18) l18) (18) (18) ,,.,, Minimum Lot Ma (1 3) 1.875 3.75 7.5~ ,SK K K Minimum Lot 1351\ 13511 1351\ 13511 "' '" "' "' "' "' "' "' "' "'"'" "' '" ,,, Minimum s1 ... 1 "" '" '" ... "' ". '" '" '" '" '" '" '" Setback ,., ,., ,., ,., OI '" ,., ,,, ,., ,., ,,, ,., ,., '" Minimum Interior .. )0, , .. , .. .. " .. .. .. .. .. .. .. Setback ,,, ,., '" ,., "' "' (101 (10) (10) (10) /Jl 1161 BaH Height ... '" '" ... '" '" '" "' '" ~· ~· '" ~· ,., "" "' ... '" ... . .. -(14f \~!! (14) (14) [14) '" Maximum 1mJWNloUI "' "" "' ,, .... "" '" ~-'" '" '" ... '" ""' Su/face; (11) (11) (11) (11) {11/ {11) I '"' )(2.5) (2Sj '"' (25) (25) '"' Perctnl;lgt (51 (19) (19) (19) {19) (251 (25) (25) (25) !~!? (25) .. -B. Development cond1t1ons. 1. This maximum density may be achieved only through the application of residential density incentives in accordance with K.C.C. chapter 21A.34 or transfers of development rights in accordance with K.C.C. chapter 21A.37, or any combination of density incentive or density transfer. Maximum density may only be exceeded in accordance with K.C.C. 21 A.34.040.F.1.g. and F.6. 2. Also see K.C.C. 21A.12.060. 3. These standards may be modified under the provisions for zero-lot-line and townhouse developments. 21A-107 I I Flow Frequency Analysis LogPearson III Coefficients Time Series File:06083dev.tsf Mean--0.530 StdDev-0.154 I Project Location:Landsburg Skew= 0.737 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob I (CFS) (CFS) Period 0.316 21 2/16/49 19:00 0.952 1 89.50 0.989 0.556 2 3/03/50 16:00 0.556 2 32 .13 o. 969 I 0.330 17 2/09/51 2:00 0. 4 93 3 19.58 0.949 0.241 37 10/15/51 13: 00 0.474 4 14. 08 0.929 0.242 36 3/24/53 15:00 0. 4 68 5 10.99 0.909 0.301 22 12/19/53 19:00 0. 465 6 9.01 0.889 I 0.159 50 11/25/54 4:00 0.447 7 7.64 0.869 0.199 45 12/11/55 13: 00 0. 429 8 6.63 0.849 0.245 33 2/24/57 14:00 0. 426 9 5.86 0.829 0.206 43 12/25/57 17:00 0. 426 10 5.24 0.809 I 0.282 24 9/26/59 14:00 0. 397 11 4.75 0.789 0.235 39 2/06/60 19:00 0. 396 12 4. 34 0.769 0.177 47 2/14/61 22:00 0.380 13 3.99 0.749 I 0.206 44 12/17/61 7:00 0.352 14 3.70 0. 729 0.244 34 2/28/63 20:00 0.349 15 3.44 0. 709 0.429 8 9/18/64 5:00 0.345 16 3.22 0.690 0.266 28 11/24/64 4:00 0.330 17 3.03 0. 670 I 0.208 42 12/03/65 17:00 0.328 18 2.85 0.650 0.328 18 9/10/67 13:00 0.319 19 2.70 0.630 0.199 46 8/24/68 17:00 0.317 20 2.56 0.610 I 0.468 5 6/23/69 21:00 0.316 21 2.44 0.590 0.253 30 11/04/69 13: 00 0.301 22 2.32 0.570 0.349 15 9/02/71 4:00 0. 297 23 2.22 0.550 0.352 14 9/10/72 15:00 0.282 24 2.13 0.530 I 0.168 49 11/25/72 14 :00 0.282 25 2.04 0.510 0.253 31 11/11/73 2:00 0.274 26 1. 96 0. 490 0. 426 10 12/27 /74 2:00 0. 267 27 1. 89 0. 4 70 0.243 35 12/29/75 15:00 0.266 28 1. 82 0. 4 50 I 0.397 11 8/26/77 1:00 0.256 29 1. 75 0.430 0.282 25 12/01/77 23:00 0.253 30 1. 70 0.410 0.175 48 2/06/79 16:00 0.253 31 1. 64 0.390 I 0.274 26 12/14/79 23:00 0.250 32 1. 59 0.370 0. 396 12 11/21/80 11: 00 0.245 33 1. 54 0.350 0.250 32 10/06/81 2:00 0.244 34 1. 4 9 0.330 0. 317 20 10/28/82 18:00 0.243 35 1. 45 0.310 I 0.447 7 1/24/84 16:00 0.242 36 1. 41 0.291 0.256 29 11/01/84 23:00 0.241 37 1. 37 0.271 0.345 16 10/22/85 17:00 0. 237 38 1. 33 0.251 I 0. 426 9 11/21/86 9:00 0.235 39 1. 30 0.231 0.227 40 5/28/88 16:00 0.227 40 1. 27 0 .211 0.237 38 1/09/89 22:00 0.219 41 1. 24 0.191 0.380 13 1/09/90 7:00 0.208 42 1. 21 0.171 I 0.465 6 10/18/90 19:00 0.206 43 1.18 0.151 0.297 23 7/06/92 16:00 0.206 44 1.15 0.131 0.219 41 3/22/93 19:00 0.199 45 1.12 0.111 0.474 4 9/10/94 14:00 0.199 46 1.10 0.091 I 0.319 19 11/30/94 5:00 0.177 47 1. 08 0.071 0.493 3 2/09/96 0:00 0.175 48 1. 05 0.051 0.952 1 9/17/97 11:00 0 .168 49 1. 03 0.031 I 0.267 27 10/29/97 6:00 0.159 50 1. 01 0.011 i 06083dev.pks Page I of2 I I I Computed Peaks 0.808 100.00 0.990 Computed Peaks o. 695 50.00 0. 980 I Computed Peaks 0.593 25.00 0.960 Computed Peaks 0.473 10.00 0.900 Computed Peaks 0.451 8.00 0.875 Computed Peaks 0.390 5.00 0.800 I Computed Peaks 0.283 2.00 0.500 Computed Peaks 0.224 1. 30 0.231 I I I I I I I I I I I I I I 06083dev.pks Page 2 of2 I I I I I I I I I I I I I I I I I I I I Retention/Detention Facility Type of Facility: Detention Vault Facility Length: 76.00 ft Facility Width: 34.00 ft Facility Area: 2584. sq. ft Effective Storage Depth: 6. 40 ft Stage 0 Elevation: 506.10 ft Storage Volume: 16538. cu. ft Riser Head: 6. 40 ft Riser Diameter: 12.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 0. 75 0.039 2 3.01 0.86 0.037 4.0 3 4.52 1. 00 0.037 4.0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 506.10 o. 0.000 0.000 0.00 0.01 506.11 26. 0.001 0.001 0.00 0.02 506.12 52. 0.001 0.002 0.00 0.03 50 6 .13 78. 0.002 0.003 0.00 0.04 506.14 103. 0.002 0.003 0.00 0.05 506.15 129. 0.003 0.004 0.00 0.06 506.16 155. 0.004 0.004 0.00 0 .19 506.29 491. 0. 011 0.007 0.00 0.31 506. 41 801. 0.018 0.009 0.00 0.44 506.54 1137. 0.026 0.010 0.00 0.56 506.66 1447. 0.033 0. 011 0.00 0.69 506.79 1783. 0.041 0.013 0.00 0.82 506.92 2119. 0.049 0.014 0.00 0.94 507.04 2429. 0.056 0.015 0.00 1. 07 507.17 2765. 0.063 0.016 0.00 1.19 507.29 3075. 0.071 0. 017 0.00 1. 32 507.42 3411. 0.078 0.018 0.00 1. 4 4 507.54 3721. 0.085 0.018 0.00 1. 57 507.67 4057. 0.093 0.019 0.00 1. 69 507.79 4 367. 0.100 0.020 0.00 1. 82 507.92 4703. 0.108 0.021 0.00 1. 94 508.04 5013. 0.115 0.021 0.00 2.07 508.17 5349. 0.123 0.022 0.00 2.20 508.30 5685. 0 .131 0.023 0.00 2.32 508.42 5995. 0 .138 0.023 0.00 2.45 508.55 6331. 0.145 0.024 0.00 2.57 508.67 6641. 0.152 0.024 0.00 2.70 508.80 6977. 0.160 0.025 0.00 2.82 508.92 7287. 0 .167 0.026 0.00 2. 95 509.05 7623. 0 .175 0.026 0.00 3.01 509 .11 7778. 0.179 0.026 0.00 vault.doc Page I of 5 I I 3.02 509.12 7804. 0.179 0.027 0.00 3.03 509 .13 7830. 0.180 0.027 0.00 I 3.04 509 .14 7855. 0.180 0.028 0.00 3.05 509.15 7881. 0.181 0.030 0.00 3.06 509.16 7907. 0.182 0.031 0.00 3.07 509.17 7933. 0.182 0.032 0.00 I 3.08 509.18 7959. 0.183 0.032 0.00 3.21 509.31 8295. 0 .190 0.036 0.00 3.33 509.43 8605. 0.198 0.039 0.00 I 3.46 509.56 8941. 0.205 0.042 0.00 3.58 509.68 9251. 0.212 0.044 0.00 3.71 509.81 9587. 0.220 0.046 0.00 3.83 509.93 9897. 0.227 0.048 0.00 I 3. 96 510.06 10233. 0.235 0.050 0.00 4.09 510.19 10569. 0.243 0.052 0.00 4. 21 510.31 10879. 0.250 0.053 0.00 4. 34 510.44 11215. 0.257 0.055 0.00 I 4.46 510.56 11525. 0.265 0.056 0.00 4.52 510.62 11680. 0.268 0.057 0.00 4.53 510.63 11706. 0.269 0.057 0.00 I 4.54 510.64 11731. 0.269 0.058 0.00 4.55 510.65 11757. 0.270 0.059 0.00 4.56 510.66 11783. 0.271 0.061 0.00 4.57 510.67 11809. 0.271 0.063 0.00 I 4.58 510. 68 11835. 0. 272 0.065 0.00 4.59 510.69 11861. 0. 272 0.065 0.00 4. 60 510.70 11886. 0.273 0.066 0.00 I 4. 61 510.71 11912. 0.273 0.066 0.00 4.74 510.84 12248. 0.281 0. 072 0.00 4.86 510. 96 12558. 0.288 o. 077 0.00 4.99 511. 09 12894. 0. 296 0.081 0.00 I 5.12 511. 22 13230. 0.304 0.085 0.00 5.24 511.34 13540. 0. 311 0.088 0.00 5.37 511. 47 1387 6. 0.319 0.091 0.00 5. 49 511. 59 14186. 0.326 0.094 0.00 I 5. 62 511. 72 14522. 0.333 0.097 0.00 5.74 511.84 14832. 0.340 0.100 0.00 5.87 511. 97 15168. 0.348 0.102 0.00 I 5.99 512.09 15478. 0.355 0.105 0.00 6.12 512.22 15814. 0.363 0.107 0.00 6.25 512.35 16150. 0.371 0.110 0.00 6.37 512.47 16460. 0.378 0.112 0.00 I 6. 40 512.50 16538. 0.380 0 .113 0.00 6.50 512.60 16796. 0.386 0.423 0.00 6.60 512.70 17054. 0. 392 0.987 0.00 I 6. 70 512.80 17313. 0.397 1. 720 0.00 6.80 512.90 17571. 0.403 2.510 0.00 6.90 513. 00 17830. 0. 409 2.800 0.00 7.00 513 .10 18088. 0.415 3.050 0.00 I 7.10 513. 20 18346. 0.421 3. 290 o.oo 7.20 513.30 18605. 0.427 3.510 0.00 7.30 513.40 18863. 0.433 3.720 0.00 7.40 513.50 19122. 0. 439 3.910 0.00 I 7.50 513. 60 19380. 0.445 4.100 0.00 7. 60 513.70 19638. 0.451 4.280 0.00 7.70 513. 80 19897. 0.457 4.450 0.00 I 7.80 513. 90 20155. 0. 4 63 4. 610 0.00 I vault.doc Page 2 of5 I I I I I I I I I I I I I I I I 7. 90 514.00 20414. 0.469 4.770 0.00 8.00 514.10 20672. 0. 4 7 5 4.920 0.00 8.10 514.20 20930. 0.480 5.070 0.00 8.20 514. 30 21189. 0. 486 5.220 0.00 Hyd Inflow Outflow Peak Storage Target Cale Stage Elev (Cu-Ft) (Ac-Ft I 1 0.33 ******* 0.12 6. 40 512.50 16540. 0.380 2 0. 49 0.14 0.10 5.86 511. 96 15136. 0.347 3 0.38 ******* 0.10 5.88 511.98 15191. 0.349 4 0.45 ******* 0.06 4.57 510.67 11816. 0. 271 5 0.40 ******* 0.08 4.89 510.99 12 64 6. 0.290 6 0.28 ******* 0.08 4.85 510.95 12534. 0.288 7 0.20 ******* 0.03 3.05 509.15 7890. 0.181 8 0 .11 ******* 0.03 3.07 509.17 7945. 0.182 ---------------------------------- Route Time Series through Facility Inflow Time Series File:06083dev.tsf Outflow Time Series File:rdout Inflow/Outflow Analysis Peak Inflow Discharge: 0. 952 CFS at 11: 00 on Sep 17 in 1997 Peak Outflow Discharge: 0.115 CFS at 20:00 on Feb 9 in 1951 Peak Reservoir Stage: 6. 40 Ft Peak Reservoir Elev: 512.50 Ft Peak Reservoir Storage: 16540. Cu-Ft 0.380 Ac-Ft Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS % % % 0.002 217138 49.575 49.575 50.425 0.504E+OO 0.005 42675 9.743 59.318 40.682 0. 4 07E+OO 0.008 44457 10.150 69. 4 68 30.532 0.305E+OO o. 011 49351 11. 267 80.735 19.265 0.193E+OO 0.015 28148 6.426 87.162 12.838 0.128E+OO 0.018 22191 5.066 92.228 7. 772 0.777E-01 0.021 15579 3.557 95.785 4.215 0.421E-01 0.024 11537 2.634 98.419 1. 581 0.158E-01 0.027 3727 0.851 99.270 0.730 0.730E-02 0.031 174 0.040 99.310 0.690 0.690E-02 0.034 446 0.102 99.412 0.588 0.588E-02 0.037 423 0. 097 99.508 0. 4 92 0.492E-02 0.040 383 0.087 99. 596 0. 4 04 0.404E-02 0.044 346 0.079 99.675 0.325 0.325E-02 0.047 360 0.082 99.757 0.243 0.243E-02 0.050 294 0. 067 99.824 0.176 0.176E-02 0.053 272 0.062 99.886 0 .114 0 .114E-02 0.056 218 0.050 99.936 0. 064 0.642E-03 0.060 33 0.008 99.943 0.057 0.566E-03 0.063 7 0.002 99.945 0.055 0.550E-03 0.066 19 0.004 99.949 0.051 0.507E-03 0.069 26 0.006 99.955 0.045 0.447E-03 0.073 21 0.005 99.960 0.040 0.400E-03 0.076 26 0.006 99.966 0.034 0.340E-03 vault.doc Page 3 of 5 I I I I I I I I I I I I I I I I I I I 0.079 29 0.007 99.973 0.027 0. 274E-03 0.082 10 0.002 99.975 0.025 0.251E-03 0.085 13 0.003 99.978 0.022 0.221E-03 0.089 14 0.003 99.981 0.019 0. 18 9E-03 0.092 10 0.002 99.983 0.017 0 .167E-03 0.095 10 0.002 99.986 0.014 0.144E-03 0.098 14 0.003 99.989 0. 011 0 .112E-03 0.102 18 0.004 99.993 0.007 0.708E-04 0.105 12 0.003 99. 996 0.004 0.434E-04 0.108 8 0.002 99. 997 0.003 0.251E-04 0 .111 8 0.002 99.999 0.001 0.685E-05 0 .114 2 0.000 100.000 0.000 0.228E-05 Duration Comparison Anaylsis Base File: 06083ex.tsf New File: rdout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time--------------Check of Tolerance------- Cutoff Base New %Change Probability 0.026 0.99E-02 0. 77E-02 -22.8 0.99E-02 0.037 0.39E-02 0.48E-02 23.0 0.39E-02 0.049 0.17E-02 0.21E-02 22.4 0.17E-02 0.060 0.74E-03 0.57E-03 -23.2 0.74E-03 0.071 0.38E-03 0.42E-03 12.0 0.38E-03 0.082 0.20E-03 0.25E-03 26.4 0.20E-03 0.093 0.91E-04 0.16E-03 72 .5 0.91E-04 0.104 0.32E-04 0.43E-04 35.7 0.32E-04 0.115 0.18E-04 0.23E-05 -87.5 0.18E-04 0.126 0.68E-05 O.OOE+OO -100.0 0.68E-05 0 .137 0.68E-05 O.OOE+OO -100.0 0.68E-05 0 .148 0.46E-05 O.OOE+OO -100.0 0.46E-05 0.159 0.46E-05 O.OOE+OO -100.0 0.46E-05 0.170 0.23E-05 O.OOE+OO -100.0 0.23E-05 Maximum positive excursion= 0.009 cfs 9.9%) occurring at 0.089 cfs on the Base Data:06083ex.tsf and at 0.098 cfs on the New Data:rdout.tsf Maximum negative excursion= 0.055 cfs {-32.2%) occurring at 0.170 cfs on the Base Data:06083ex.tsf and at 0.115 cfs on the New Data:rdout.tsf Base New 0.026 0.026 0.037 0.041 0. 049 0.050 0.060 0.056 0. 071 0.074 0.082 0.088 0.093 0.101 0.104 0.107 0 .115 0.110 0.126 0 .112 0.137 0 .112 0.148 0.112 0.159 0.112 0.170 0.115 Flow Frequency Analysis LogPearson III Coefficients %Change -1. 7 9.1 3.7 -6. 7 4.6 8.0 8.4 2.7 -4.6 -11. 2 -18.4 -24.4 -29.6 -32.2 Time Series File:rdout.tsf Mean~ -1.392 StdDev~ 0.215 Project Location:Landsburg ---Annual Peak Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.026 40 2/17/49 7:00 0.050 18 3/05/50 6:00 0.115 1 2/09/51 20:00 0.023 46 2/01/52 5:00 0.039 23 1/12/53 7:00 0.045 20 1/06/54 8:00 0.032 32 2/08/55 4:00 0.032 33 12/11/55 22:00 0.026 39 12/13/56 0:00 vault.doc Skew~ 0. 475 -----Flow Frequency Analysis------- --Peaks --Rank Return Prob {CFS) {ft) Period 0.115 6.40 1 89.50 0.111 6.30 2 32.13 0.102 19.58 5.88 3 0.102 14.08 5.86 4 0.081 10.99 5.00 5 0.078 9.01 4.89 6 0.077 7.64 4.85 7 0.076 6.63 4.84 8 0.069 4. 68 9 5.86 Page 4 of5 0.989 0. 969 0.949 0.929 0.909 0.889 0.869 0.849 0.829 I I 0.024 44 1/17/58 11: 00 0.069 4. 67 10 5.24 0.809 0.037 27 1/24/59 17:00 0.064 4.57 11 4.75 0.789 I 0.069 9 11/21/59 4:00 0.057 4.52 12 4.34 0.769 0.051 17 11/20/60 18:00 0.056 4.44 13 3.99 0.749 0.022 48 12/19/61 17:00 0.056 4.41 14 3.70 0. 729 0.025 41 2/03/63 9:00 0.054 4.28 15 3.44 0.709 I 0.037 28 1/25/64 11: 00 0.053 4.24 16 3.22 0.690 0.057 12 1/30/65 13: 00 0.051 4.03 17 3.03 0. 670 0.021 49 11/05/65 3:00 0.050 3.95 18 2.85 0.650 I 0.026 36 12/13/66 17:00 0.048 3.86 19 2.70 0.630 0.036 29 6/03/68 9:00 0.045 3.66 20 2.56 0.610 0.040 22 1/07/69 10:00 0.044 3.56 21 2.44 0.590 0.026 34 12/14/69 9:00 0.040 3.39 22 2.32 0.570 I 0.038 26 1/09/71 14:00 0.039 3.33 23 2.22 0.550 0.056 13 3/01/72 7:00 0.038 3.29 24 2 .13 0.530 0.038 25 12/27/72 21:00 0.038 3.28 25 2.04 0.510 I 0.032 31 1/16/74 18:00 0.038 3.27 26 1. 96 0.490 0.026 35 11/21/74 18:00 0.037 3.27 27 1. 89 0. 470 0.054 15 12/04/75 3:00 0.037 3.24 28 1. 82 0.450 0.024 45 8/26/77 6:00 0.036 3.20 29 1. 75 0.430 I 0.077 7 12/03/77 0:00 0.034 3.14 30 1. 70 0.410 0.024 43 2/12/79 18:00 0.032 3.07 31 1. 64 0.390 0. 076 8 12/15/79 16:00 0.032 3.07 32 1. 59 0.370 0.078 6 12/03/80 23:00 0.032 3.07 33 1. 54 0.350 I 0.034 30 1/24/82 1:00 0.026 2.94 34 1. 49 0.330 0.056 14 1/05/83 16:00 0.026 2.88 35 1. 45 0.310 0.064 11 1/25/84 3:00 0.026 2. 85 36 1. 41 0.291 I 0.053 16 11/03/84 18:00 0.026 2.82 37 1. 37 0.271 0.044 21 10/28/85 1:00 0.026 2.81 38 1. 33 0.251 0 .111 2 11/24/86 8:00 0.026 2.79 39 1. 30 0.231 0.038 24 3/27/88 14:00 0.026 2.78 40 1. 27 0.211 I 0.026 38 11/06/88 2:00 0.025 2. 67 41 1. 24 0.191 0.102 3 1/09/90 17:00 0.025 2.67 42 1. 21 0.171 0.069 10 11/24/90 16:00 0.024 2.57 43 1.18 0.151 I 0.026 37 1/30/92 11: 00 0.024 2.53 44 1.15 0.131 0.025 42 1/26/93 9:00 0.024 2.43 45 1.12 0.111 0.019 50 12/01/93 19:00 0.023 2.26 46 1.10 0.091 0.048 19 2/19/95 20:00 0.022 2.07 47 1. 08 0. 071 I 0.102 4 2/09/96 4:00 0.022 2.04 48 1. 05 0.051 0.081 5 1/03/97 2:00 0.021 1. 86 49 1. 03 0.031 0.022 47 10/30/97 12:00 0.019 1. 57 50 1. 01 0. Oll Computed Peaks 0.152 6. 41 100.00 0.990 I Computed Peaks 0.126 6. 40 50.00 0.980 Computed Peaks 0.104 5.94 25.00 0. 960 Computed Peaks 0.078 4.89 10.00 0.900 I Computed Peaks 0.073 4.77 8.00 0.875 Computed Peaks 0.061 4.56 5.00 0.800 Computed Peaks 0.039 3.33 2.00 0.500 Computed Peaks 0.028 3.04 1. 30 0.231 I I I I vault.doc Page 5 of5 -- ui u. ~ Q) Cl ~ "' _c; <) "' i5 ----.a;.,-------·- co ~. c:i ~-1---------4------------------ c:i N ~. c:i 0 ~. c:i <X> 0 c:i co 0 c:i I "'!" c:i ~ c:i 0 0 I 10 -6 R<>--- 000 00 Ii Ii l ij 10 .5 i i I I I I 10'-4 I I I! i 10' .3 Probability Exceedence I' 10 -2 ---- I 11 10 -1 rdout.dur ,o target.dur o ·~ ~) I i Ii J 100 I I I I I I I I I I I I I I I I I I C. Water Quality Volume Calculations Basic Water Quality Treatment shall be utilized to mitigate for the developed storm drainage flows. The dead storage portion of the combination water quality/detention vault will satisfy this requirement. The required volume was designed per 2005 KCS WDM Section 6.4.1.1. The following variables were used in the calculation: Volume Factor (f) = 3 Rainfall = 0.041 feet or 0.49 inches Area= developed basin tributary to proposed water quality facility Where Ai = area of impervious surface (sf) A,g = area of till soil covered with grass (sf) A,r = area of till soil covered with forest (sf) A0 = area of outwash soil covered with grass or forest (sf) V, = [0.9Ai + 0.25A1g + O.IA,r+ O.OlA 0 ] * (R/12) Vb= f*Vr Vb= 3*[(0.9)(0.82) + (0.25)(0.70))0.041 * (43560sf/ac) = 4,892 CF The I" cell of the vault accommodates a dead storage volume of 14'*19'*5.48' = 1,458 CF. The 2°d cell of the vault accommodates a dead storage volume of 14'*57'*5.48' = 4,373 CF. The vault therefore, provides a total dead storage volume of 1,458 + 4,373 CF = 5,831 CF which exceeds the required 4,892 CF. I I I I I I I I I I I I I I I I I I I 6.4.1 WETPONDS ~ BASIC AND LARGE~ METHODS OF ANALYSIS FIGURE 6.4.1.A PRECIPITATION FOR MEAN ANNUAL STORM IN INCHES (FEET) ST 1.1 0.54" (0.045') [Z2J Incorporated Area ....c::::> River/Lake Major Road 0.47" (0.039') 0.47" (0.039') NOTE: Areas east of the easternmost lsopluvial should use 0.65 inches unless rainfall data Is avallable for the location of Interest 24 The mean annual storm Is a conceptual storm found by dividing the annual precipitation by the total number of storm events per year LUU5 Surface Water Design Manual 6-71 0.56" (0.047') LA 1.0 LA 1.2 U•O>t0Mj$~ COUNH S~TEt) 1/24/2005 I I I I I I I I I I I I I I I I I I I 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN: 1481h Ave NE Frontage Conveyance To size the conveyance system along 148th Avenue NE an analysis of the upstream tributary basin was completed. Since the outfall of the conveyance system is the downstream road side ditch, no backwater conditions were assumed. Topographical data and aerial photos were used to delineate the upstream tributary basin. The 7.56 acre basin consists of one single family residence with outbuildings and landscaping along 148 1h Avenue NE, and pasture and forest behind the residence to the east. Table 3.2.2.D was used to calculate the impervious area outside of the right of way. The impervious area was conservatively calculated at 15% since the actually density of the basin is below one dwelling unit per acre. For the 7 .56 acres tributary to the site, this would be 1.13 acres of impervious surfaces. In addition to the 1.13 acres of impervious surfaces in the tributary lots, the 0.07 acres ofimpervious148th Ave NE right of way must also be included. The remaining site was delineated from the aerial photographs and is broken out below. For clarification, see the upstream exhibit on the following pages. UPSTREAM TRIBUTARY TO 148™ AVE NE FRONTING SITE (upstream tributary.tsf) Total Area= 7.56 acres GROUND COVER AREA(acre) Till Forest 3.47 Till Pasture 2.48 Till-Grass (Landscaping) 0.41 Impervious 1.20 KCRTS was used to create a 15-min time series to calculate the upstream flow. The unmitigated 100-year return period storm from the tributary area will be used to asses the minimum required slope. The I 00-year return period flow for the upstream basin (upstream_tributary.tsf) is 2.75 cfs. See attached KCRTS Flow Frequency Analysis on the following pages. Since the conveyance system along 148th Ave NE also collects the runoff from the onsite detention vault, the discharge of the I 00 year storm was also assumed to be flowing in the pipe. Combining the 0.15 cfs of flow from the onsite detention facility calculated in I I I I I I I I I I I I I I I I I I I Section 4B (rdout.tst) with the 2.75 cfs of upstream flow, 2.90 cfs of flow is assumed through the conveyance system during the I 00-year event. The conveyance system along 148th Ave NE is 12" pipe and the minimum slope is 0.6%. Using Manning's equation, this conveyance system can carry the following flow: 2 I Q 1.49 A R 3 S2 (full) =--X X X n 2 = J.49 X l'it X 0.53 X 0.0061 0.012 4 2 Q<flonJ = 3.00 cfs The 3.00 cfs is more than the generated flow of2.90cfs. Therefore, a 12" pipe at 0.6% will exhibit free flow conditions for the generated 2.90 cfs of flow. The proposed system is therefore, adequately designed to handle the required flows and will not exhibit backwater effects. I I I I I I I I I I I I I I I I I I I SECTION 3.2 RUNOFF COMPUTATION AND ANALYSIS METHODS 1/24/2005 Dwelling Units/Gross % lmpervious1'1 Dwelling Units/Gross Acre Acre 1.0 DU/GA 1512) 4.5 DU/GA 1.5 DU/GA 20 5.0 DU/GA 2.0 DU/GA 25 5.5 DU/GA 2.5 DU/GA 30 6.0 DU/GA 3.0 DU/GA 34 6.5 DU/GA 3.5 DU/GA 38 7.0 DU/GA 4.0 DU/GA 42 7.5 DU/GA For PUDs, condominiums, apartments, commercial businesses, and industrial areas, percent impeivious coverage must be computed. Notes: 1'1 Includes streets and sidewalks. % Impervious 46 48 50 52 54 56 58 121 These figures should be adjusted by the effective impervious fraction given in Table 3.2.2.E, if applicable. Values from Table 3.2.2.E may be interpolated as necess_ary. 2005 Surface Water Design Manual 3-28 I I I I I I I I I I I I I I Onsite Conveyance The conveyance system was designed for the 25-year, 24-hour and I 00-year, 24-hour storm events. A conveyance sheet was generated using the rational method to calculate flows for each area collected by each catch basin. See attached Catch Basin Sub basin Map on the following pages. The precipitation rates for the 25-year, 24-hour and I 00- year, 24-hour storm events are 3.45 inches and 3.94 inches consecutively. The flows generated from the conveyance system spreadsheet for both storm events were input into backwater analysis spreadsheets to confirm adequate sizing. The backwater analysis was performed to ensure that during the 25-year, 24-hour storm event, the headwater elevation in each structure did not overtop any of the rims. For the I 00-year, 24-hour storm event structures are allowed to overtop, but all runoff must be safely conveyed to ensure that overflowing runoff or ponding would not cause structural damage. A weighted C value was used for each area collected by each catch basin. The average C value is based on the total area collected by the catch basins. The total catch basin area tributary to the combination detention/water quality vault is equal to the developed conditions tributary to the vault as delineated in Section A of this Report. The average C value is (0.70*0.25 + 0.82*0.90)/1.52 = 0.60. The tailwater elevations within the combination detention/water quality vault were derived from the KCRTS outfall information. See Section B of this Report. The 25-year and I 00-year tailwater elevations are El. 512.04 and El. 512.51 consecutively. Per the attached backwater spreadsheet all flow during the 25-year storm was maintained within the conveyance system. During the I 00-year storm, runoff overtopped CB 4 and CB 5. Due to the topography of the site, the runoff will be safely conveyed down J4gth Avenue NE to the next downstream conveyance structure, CB I. Both storm events meet the requirements of the KCSWDM and therefore the conveyance system is adequately designed. The outfall design for Outfall IA is based on the I 00 year storm event, 2.90 cfs. This includes the tributary 100-year, 15-minute return period storm, 2.75 cfs and the discharge of the detention vault 0.15 cfs. The pipe upstream of Outfall I A can carry a full flow of 2 I Q 1.49 A R' s2 (full) =--X X X n 2 = 1.49 X I'1t X o.s, X 0.0061 0.012 4 2 Q(fullJ = 3.00 cfs I I Computed Peaks 2.75 100.00 0.990 Computed Peaks 2.44 50.00 0.980 I Computed Peaks 2.15 25.00 0.960 Computed Peaks 1. 75 10.00 0.900 Computed Peaks 1. 67 8.00 0.875 Computed Peaks 1. 4 5 5.00 0.800 I Computed Peaks 1. 02 2.00 0.500 Computed Peaks 0.738 1. 30 0.231 I I I I I I I I I I I I I I upstream_ tributary .pks Page 2 of2 I I I Flow Frequency Analysis LogPearson III Coefficients Time Series File:upstream_tributary.tsMean= 0.008 StdDev-0.184 I Project Location:Landsburg Skew-0. 027 ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Return Prob I (CFS) (CFS) Period 1. 37 15 2/16/49 17:30 2.19 1 89.50 0.989 1. 52 10 3/03/50 14:45 2.15 2 32 .13 o. 969 I 0.903 29 2/09/51 3:00 2.03 3 19.58 0.949 0. 772 35 11/28/51 18:15 1. 98 4 14. 08 0. 929 0.669 41 2/03/53 16:45 1. 98 5 10.99 0.909 1. 37 16 9/16/54 16:00 1. 66 6 9.01 0.889 I 0.575 45 5/13/55 0:15 1. 62 7 7.64 0.869 0.523 49 12/22/55 6:15 1. 59 8 6.63 0.849 0. 872 31 2/24/57 13: 15 1. 58 9 5.86 0.829 I 0.731 37 12/25/57 16:00 1. 52 10 5.24 0.809 1. 28 17 9/26/59 13:30 1. 52 11 4.75 0.789 0.704 38 10/24/59 10:45 1. 51 12 4.34 0.769 0.630 43 4/29/61 14:00 1. 43 13 3.99 0.749 I 0.442 50 10/09/61 17:45 1. 40 14 3.70 0. 729 1.23 19 2/28/63 19:00 1. 37 15 3. 4 4 0.709 2.03 3 9/18/64 4: 15 1. 37 16 3.22 0.690 0.767 36 11/24/64 2:45 1. 28 17 3.03 0. 670 I 0. 671 40 5/06/66 7:15 1.25 18 2.85 0.650 0.935 27 9/10/67 11: 30 1.23 19 2.70 0.630 1. 04 25 6/02/68 3:15 1.19 20 2.56 0.610 I 1. 51 12 6/23/69 20:00 1.18 21 2.44 0.590 0.544 47 6/29/70 14:45 1.16 22 2.32 0.570 1. 98 4 9/02/71 2:00 1.10 23 2.22 0.550 1. 43 13 6/25/7 2 2:15 1. 09 24 2.13 0.530 I 0.540 48 10/25/72 10:15 1. 04 25 2.04 0.510 0.831 33 11/11/73 0:30 0. 960 26 1. 96 0.490 1. 40 14 12/27 /74 1:15 0.935 27 1. 89 0.470 I 0.872 32 7/08/76 23:00 0. 927 28 1. 82 0.450 1.16 22 8/25/77 23:30 0.903 29 1. 75 0.430 1.18 21 9/22/78 18:00 0.897 30 1. 70 0.410 0.569 46 11/04/78 20:45 0. 872 31 1. 64 0.390 I 0. 960 26 12/15/79 6:15 0.872 32 1. 59 0.370 1. 52 11 5/10/81 22:00 0.831 33 1. 54 0.350 0.681 39 10/06/81 1:00 0.780 34 1. 4 9 0.330 0.897 30 9/10/83 16: 45 0. 772 35 1. 45 0.310 I 1. 98 5 10/30/83 13: 00 0. 767 36 1. 41 0. 291 0.667 42 11/01/84 20:00 0.731 37 1. 37 0.271 1. 59 8 10/22/85 16:15 0.704 38 1. 33 0.251 I 1.10 23 11/21/86 8:00 0.681 39 1. 30 0.231 0.780 34 12/03/87 3:00 0. 671 40 1.27 0. 211 0.628 44 11/22/88 12:45 0.669 41 1. 24 0.191 1. 66 6 1/09/90 11: 15 0. 667 42 1. 21 0.171 I 1. 25 18 10/18/90 18:30 0.630 43 1. 18 0.151 1.19 20 4/18/92 18:00 0.628 44 1.15 0.131 1. 58 9 5/21/93 15:00 0.575 45 1.12 0.111 I 0. 927 28 10/31/93 15:00 0.569 46 1.10 0.091 1.09 24 9/27 /95 15:15 0.544 47 1. 08 0.071 2.15 2 5/14/96 6:15 0.540 48 1. 05 0.051 2.19 1 9/18/97 4:30 0.523 49 1. 03 0.031 I 1. 62 7 8/16/98 15:15 0.442 50 1. 01 0. 011 upstream_tributary.pks Page I of2 I 1...------------------------------, I I .. IMPERVIOUS R/W (0. 07 AC) TILL PASTlJRE (248 AC) TILL LANDSCAPING (0..f.1 AC) TILL FOREST (3. .f.1 AC) IMPERVIOUS LOT CO'ERAGE (1.13 AC) roiE ~DESIGN 14711 NE 29111 l'looo, #101 __ W.......,.98007 ~ h,,t42S.&8$.7H3 ENGINEHING · PlANNING · SURVEYING UPSTREAM TRIBUTARY PLEASANT PATH DATE APRIL 2008 DESIGNED NWD DRAWN NWD PROJECT NUMBER 06083 I I I I I I I I I I I I I I I R I I I and a full flow velocity of 2 I V 1.49 R' S' (full) =--X X n ~ I = I.49 X O.S 3 X 0.006 2 0.012 2 v(full) = 3 .82 fps Since the full flow velocity is less than 5 fps and the I 00 year storm event is below full flow, a rip rap outfall was designed based on the discharge velocity falling within the range of O to $ 5 fps per Table 4.2.2.A. I I I I I I I I I I I I I I I I I I I 4.2.3 PUMP SYSTEMS Discharge Velocity at Design Flow (fps) Greater than 0 5 10 20 Less than or equal to 5 10 20 N/A REQUIRED PROTECTION Minimum Dimensions1 1l Type Thickness Width Length Rock lining 12 > 1 foot Diameter 8 feet + 6 feet or 4 x diameter, whichever is greater Riprapl3> 2 feet Diameter 12 feet + 6 feet or or 4 x diameter, 3 x diameter, whichever is whichever is greater greater Gabion As required As required As required outfall Engineered energy dissipater required Height Crown + 1foot Crown + 1 foot Crown + 1 foot 11 > These sizes assume that erosion is dominated by outfall energy. In many cases sizing will be governed by conditions in the receiving waters. 12 > Rock lining shall be quarry spalls with gradation as follows: Passing 8-inch square sieve: Passing 3-inch square sieve: Passing 3/4-inch square sieve: 100% 40 to 60% maximum O to 10% maximum 13> Riprap shall be reasonably well graded with gradation as follows: Maximum stone size: Median stone size: Minimum stone size: 24 inches (nominal diameter) 16inches 4 inches Note: Riprap sizing governed by side slopes on outlet channel is assumed to be approximately 3:1. 2005 Surface Water Design Manual l/24i2005 4-31 I I I I I I I I I I I I I I I I I I I SECTION 3.2 RUNOFF COMPUTATION AND ANALYSIS METIi ODS FIGURE 3.2.1.C 25-YEAR 24-HOUR ISOPLUVIALS WIESTIEIRN IK!ING COUJJNTY 25-Year 24-Hour Precipitation in Inches 1/24/2005 -,,... - 0 2 4Miles 3-16 SH ~~S_!\.£2!!'!,!.! KING COUNTY .. 2005 Surface Water Design Manual I I I I I I I I I I I I I I I I I I I FIGURE 3.2.1.D JOO-YEAR 24-HOUR ISOPLUVIALS WIES1J"IERN KING COllJNlJ"Y 100-Year 24-Hour Precipitation in Inches 2005 Surface Water Design Manual 0 2 4 Mites 3-17 3.2.1 RATIONAL METHOD 1/24/2005 I --·-. --. --. ----",·~--I II 11 __________ VJ \\ I l!1K\ I ! I ·····=·-·==~~~ \ 11 I I I I I"· -·~ 11 11~1ir I /1 0 / j 1"-I If/ 1 11' I\~ ' I I ~ ~ I I Im lij " l•I I', ., 1· i : •. I • •. ii I; 2 1 \ B 5 p 45 AC~- \ y~ = ~- ·.·1· ... ;, ·J 4 T CB 6 ( 0.24 AC I 5 TRACT C \. JOINT USE DRIVEWA.Y II~ ~1 ; \.~ ~ \ \ 1 ~,~~1-c Ill ~·. I\ ~ \J \ 8 -] I 6 II ~\ , 1111 ~ 1\1 \ ~----~) \ \ \ \ ) l_ II '~~-" f l 1 ~ /, 11 'IBI ,,~ ,~\. . 1'\ ~. "ri1 1 l ( 1 1 1 t 1 SCALE: 1 " = 50' 0 12.5 25 50 @~a<~-~-IQIINE ........ #101 ,'·"" ....--. w~ 980(Q -. ,(ll.lJ85..7B77 hu 42$.88.S.7963 ~DESIGN ENGINEEIING · PLANNING, SUIVEYING CATCH BASIN SUBBASIN MAP .. PLEASANT PATH DA TE APRIL 2008 DESIGNED NWD DRAWN NWD PROJECT NUMBER 06083 ------------------- ······•·•·••••sr~•oP~~NcJtsfs1t¢M1•0Est~N ••••••••••·•! LOCATION, KING COUNTY 24-HR RAINFALL: 3.4~ INCHES I OBNAME: PLEASANTPATH JOBNUMBER: 06083 NWD DESIGNSTORM: 2!'i YEAR , t1t:;rt •~~~~ ~:~ :~~ ;; 1 r~1t ~1~ 1;~ 11 }I ~~t~ ~~~9t;m;~: CB 8 0.436 0.60 0.262 0.262 6.30 2.77 0.726 0.012 12 0.500 19 2.92 0.11 2.729 3.47 26.6% CB 7 I CB 6 I 0.023 I 0.60 0.014 0.275 6.30 2.77 0.763 0.012 12 0.800 65 3.52 OJI 3.452 4.40 22.1% CB 6 I CB 3 I 0.243 I 0.60 0.146 0.421 6JO 2.77 1.167 0.012 12 5.200 75 7.45 0.17 8.801 I L.21 13.3% CBS I CB4 0.453 0.60 0.272 0.272 6.30 2.77 0.754 0.012 12 l.000 50 J.71 0.22 3.860 4.91 19.5% CB4 I CB3 0.161 0.60 0.097 0.369 6.30 2.77 1.023 0.012 12 0.500 51 :us 0.27 2.729 3.47 37.5% CBJ I 3A 0.205 0.60 O.I23 0.912 6.30 2.77 2.531 0.012 12 136300 4 28.97 0.00 45.061 57.37 5.6% I I I I I I I I I I I I I I I I I I I ;'; ;}f , ':;;!:/ . _ ~;. '".l • t:lf!~C~W~tER; eAt9,ictJLAJ,JIQIW${j1 ,. " Jr ", "''' ,-f ~. ~ <t;1}~ ;J,: :~ :::~~~.::.1 1 3;,~ ~: .tif:·~; ~~.~~; f[~itL'. :t~ll'.i ·1/i }flpw\[f:i:~l. VE:J~txt~ t~!J1{~k ·~;;1~~· 1;t~§J /~t~! :~!:~ 1c~1fit~·, ttt~~;~~ ·~!~tftf~ ~~;:, .J~i~~~ ~~i~~i ,.-.,~~- : FR0~1 ,. T?. . , n,ow , HiN_<;T'! . R',t·: ,: ,. ;': • ,n. • • , t;LE.v t:'!I':JN ~L.~VAT(ON , Ac.RE}_ ,vEL(?CITY(y~LOCJT,Y , 1,HEAI>o, ,ELE:Y ~I'oN "',J.L9!>8 • f.!;'EVATI,?1'\ ·',,!'.Oss j: < Lpss: · E,LE:V;\,:I,:IP~ l~EY ~Tl!:!!':'. /,'.:"E1D'.'·'-,; ';"Lf:'~', ::: LOJ~ ·J , ELE,v~:rm.N/ , ';c, ' ,,;;CB: , .: < ·CB • · (CFS):, : (FEET)i , .,(IN)r' •·• YA LUE., : <,w .• (FEET) cc· ·,,; (FEET) , · (SQ FT) '(FT/SEC) [.(FT/SEC). · • (FEET): , ,: (FEET)., ., 1 · •(FEET).' ;.,: (FEETJe·< 1 "(FEET);.,, ·;(FEET). ,":,(FEET)·,:, ·,, (l'EET) , : < .. s(FEET) , . .11 . (FEET)'' '.'.(FEET) ;· · ' .. (l'EET)·' . · RIM'EL I lNLETJA CB3 2.53 4 12 0.012 504.10 509.55 0.79 3.22 57.52 0.1613 512.05 0.0170 512.07 0.0807 0.1613 512.31 510.s5 I 0.03431 0.14201 0.50601 512.92 I 514.so CB3 CB4 1.02 50 12 0.012 509.55 509.98 0.79 1.30 4.57 0.0264 512.92 0.0348 512.96 0.0132 0.0264 513.00 510.98 0.01431 0.01691 0.00001 513.oo I 513.02 CB4 CB 5 0.75 51 12 0.012 509.98 510.25 0.79 0.96 3.59 0.0143 513.00 0.0193 513.02 0.0072 0.0143 513.04 5 l l.25 0.000'!.[ 0.00001 0.00001 513.04 J 513.32 CB3 CB6 LI? 75 12 0.012 509.55 513.40 0.79 1.49 11.16 0.0343 512.92 0.0679 514.40 0.0172 0.0343 514.45 514.40 0.0147 0.0343 0.0000 514.47 517.72 ' CB6 CB7 0.76 65 12 0.012 513.40 513.92 0.79 0.97 4.41 0.0147 514.47 0.0251 514.92 0.0073 0.0147 514.94 514.92 0.0133 0.0094 0.0000 514.94 517.64 CB7 CB8 0.73 19 12 0.012 513.92 514.02 0.79 0.92 3.57 0.0133 514.94 0.0067 515.02 0.0066 0.0133 515.04 515.02 0.0000 0.0000 0.0000 515.04 517.64 ------------------- ···········•·•stojmco~filc1t•SYstJ.tM1•uEstGN••• •••·•• 1 LOCATION, KING COUNTY 24-HR RAINFALL: 3.94 INCHES OB NAME: PLEASANT PATH JOB NUMBER: 06083 NWD DESIGN STORM: 100 \'EAR '!~; 'll''il;l'iiii'i::: ~~i'i3'iiii\liiZ': ilil1i'~;l:";~~";;;~' CB 8 CB 7 0.436 0.60 0.262 0.262 6.30 '23 0.500 19 3.02 0.10 2.729 3.47 30.9'% CB7 I CB6 0.023 0.60 0.014 I 0.21s 6.30 3.23 0.888 0.012 12 I o.soo 65 3.60 0.30 3.452 I 4.40 25.7% CB6 ( CB3 0.243 0.60 0.146 I 0.421 6.30 3.23 1.357 0.012 12 I s.200 75 7.79 0.16 8.801 I JUI 15.4% CBS I C84 0.453 0.60 0.212 I 0.212 6.30 3.23 0.877 O.OI2 12 I 1.000 50 3.93 0.21 3.860 I 4.91 22.7% C84 I CBJ 0.161 0.60 0.091 I o.369 6.30 3.23 1.189 0.012 12 I o.soo 51 3.32 0.26 2.729 I 3.47 43.6% CB 3 I 3A 0.205 0.60 o.123 I o.912 6.30 3.23 2.942 0.012 12 I 136.Joo 4 30.98 0.00 45.061 I s1 . .11 6.5% I I I I I I I I I I I I I I I I I I I ) • ,,~. f'; ,. ·-, ~ •._ 0 , _ .~C---_-.9,r ~ i,_. •~-;,. -~----·-···"'•-5_; "··_-c··-=· .• ·''' cc-·_-.f· :.,.-,.~,;;-·a.· '," · ··" . ;· · ·-" · -·, "· •. 'a. :,JB.A((;;K:WA1GJffiRJGAJLClUIDA'.fliON§ ---·----~·''-'a-c' ''c'l"L. ___ ,~"j,',,-•,c·,,~:" ·-"~---'-·'--'--··~·,'_;:_ ___ =,••a.'•".c---·-------, __ ,__'.~' -··~ ---"---· < ,;;_ 's ',,:.J" \ L/ .,.}' --··:,-~ cmt c r. CB· -~FS)'c-::(FEET) J; (IN).... ' -. VALUE<,, ,; •'(FEET)•'• ' (FEET)·_, .(SQ':F;I') T(IT/SEC) , >(FT/SEC)~ -"' (FEET)-0,' ,,, , (FEET) ,.~ ' ::(FEET)°' -,,(FEET)}.,'.) ,L (FEET)' •. : (FEET)" ~-7(fEET)' ·: (FEET)', ' . ',(FEET)' · . ,(FEET)' CC (FEET):' , (FEET)• · · RIM,EL INLETJA CB3 2.94 4 12 0.012 504.10 509.55 0.79 3.75 57.52 0.2182 512.51 0.0230 512.53 0.1091 0.2182 512.86 510.IO 0.0464 0.1920 0.5525 513.56 514.50 CB 3 CB4 1.19 50 12 0.012 509.55 509.98 0.79 1.51 4.57 0.0356 513.56 0.0470 513.61 0.0178 0.0356 513.66 510.98 0.0194 0.0228 0.0000 513.66 513.02 CB4 CBS 0.88 51 12 0.012 509.98 510.25 0.79 1.12 3.59 0.0194 513.66 0.0261 513.69 0.0097 0.0194 513.72 511.25 0.0000 0.0000 OcOOOO 513.72 513.32 CB3 CB6 1.36 75 12 0.012 509.55 513.40 0.79 1.73 11.16 0.0464 513.56 0.0918 514.40 0.0232 0.0464 514.47 514.40 0.0199 0.0464 0.0000 514.50 517.72 CB6 CB7 0.89 65 12 0.012 513.40 513.92 0.79 1.13 4.41 0.0199 514.50 0.0341 514.92 0.0099 0.0199 514.95 514.92 0.0180 0.0127 0.0000 514.94 517.64 CB 7 CB8 0.84 19 12 0.012 513.92 514.02 0.79 1.07 3.57 0.0180 514.94 0.0090 515.02 0.0090 0.0180 515.05 515.02 0.0000 0.0000 0.0000 515.05 517.64 I I I I I I I I I I I I I I I I I I I Sewall Wetland Consulting, Inc. 1103 W. Meeker Street I 1 Kent, WA 98032 I Sewall Wetland Consultin , Inc. JOHNSEINE PROPERTY WJETLAND ANALYSIS REPORT KING COUNTY, W ASJDNGTON Prepared For: Robert Johnseine 9805 NE 1161h Street #7499 Kirkland, WA 98034 October 10, 2006 Job #A6-209 Phone: 253-859-0515 Fax: 253-852-4732 I I I I I I I I I I I I I I I I I I I Sewall Wetland Consultin , Inc. 1103 W. lv\eeker St Kai, WA 98032-6751 JOHNSJE:n:N PROPJERTY WJETJLAND ANAJL YS:n:S RJEPORT KING COUNTY, WASHINGTON 1.0 INTRODUCTION 1.1 Location Fmne: 253659-0515 Fax: 253-852-4732 This report describes the jurisdictional wetlands located on the Johnseine Property. The 3 .93 acre property is located within the urban growth area along the east side of 148th Avenue SE (parcels 1123059010, 1123059092) in unincorporated King County, Washington. 1.2 Existing Conditions 1 ._.!L .. • • "''"' • •IN f The property contains a single family home with several out buildings. The western half of the property is maintained lawn, the eastern half of the property is comprised of a forested area which appears to be at least 3nl growth mixed deciduous. The south and Formerly known as 8-12 Wetland Consulting, Inc I I I I I I I I I I I I I I I I I I I Re: Johnseine Property SWC Job# A6-209 Ootober I 0, 2006 Page 2 of8 east side of the site is bordered by high density development. The property is bordered by a single family to the north, and is bordered to the west by single 148th Avenue SE. Kin Coun I-ma I I I I I I I I I I I I I I I I I I I 2.0 METHODOLOGY Re: Johnseine Property SWC Job# A6-209 October 10, 2006 Page 3 of8 On July 20, July 28, and August 3, 2006, and again on August 7, 2006, Sewall Wetland Consulting Inc. inspected the site for jurisdictional wetlands and streams using methodology described in the Washington State Wetlands Identification Manual (W ADOE, March 1997). This is the methodology currently recognized by the King County, the City of Renton and the State of Washington for wetland determinations and delineations. The Washington State Wetlands Identification Manual as well as the 1987 Federal Manual requires the use of the three-parameter approach in identifying and delineating wetlands. A wetland should support a predominance ofhydrophytic vegetation, have hydric soils and display wetland hydrology. To be considered hydrophytic vegetation, over 50% of the dominant species in an area must have an indicator status of facultative (FAC), facultative wetland (FACW), or obligate wetland (OBL), according to the National List of Plant Species That Occur in Wetlands: Northwest (Region 9) (Reed, 1988). A hydric soil is "a soil that is saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions in the upper part." Anaerobic conditions are indicated in the field by soils with low chromas (2 or less), as determined by using the Munsell Soil Color Charts; iron oxide mottles; hydrogen sulfide odor and other indicators. Generally, wetland hydrology is defined· by inundation or saturation to the surface for a consecutive period of 12.5% or greater of the growing season. Areas that contain indicators of wetland hydrology between 5%-12.5% of the growing season may or may not be wetlands depending upon other indicators. Field indicators include visual observation of soil inundation, saturation, oxidized rhizospheres, water marks on trees or other fixed objects, drift lines, etc. Under normal circumstances, indicators of all three parameters will be present in wetland areas. 3.0 OBSERVATIONS 3.1 Existing Site Documentation Prior to visiting the site, a review of several natural resource inventory maps was conducted. Resources reviewed included the King County Soil Survey, King County Sensitive Areas Folio: Wetlands, King County Sensitive Areas Folio: Streams, City of Renton Inventory and the National Wetland Inventory. 3.1.1 King County Soil Survey According to the King County Soil Survey, the site contains Alderwood gravelly, sandy loam (AgC), which typically occurs on slopes of 6-15 percent. Alderwood soils are moderately well drained, and were formed under conifers, in glacial deposits. According to the publication "Hydric Soils of the United States," Alderwood soils are not considered Hydric or wetland soils. I I I I I I I I I I I I I I I I I I I 3.1.2 King County Sensitive Areas Folio: Wetlands and Streams Re: Johnseine Property SWC Job# A6-209 October 10, 2006 Page 4 of8 According to the King County Sensitive Areas Folios, there are no wetlands or streams located on or within 300-feet of the property. There is a wetland identified as 23b, this wetland appears to be located further than 300-feet away and associated with a larger wetland area near Highway 900. 3.1.3 City of Renton Inventory According to the City of Renton Streams and Lakes Inventory (figure 4-3-050Q4) and the City of Renton Wetland Inventory (figure 4-3-050Q5), there are no streams, Lakes or Wetlands located on or near the property. I I I I I I I I I I I I I I I I I I I 3.1.4 National Wetland Inventory Re: Johnseine Property SWC lob# A6-209 October I 0, 2006 Page5of8 According to the National Wetland Inventory, there is a PFOC (palustrine, forested, seasonally flooded) wetland located near the center of the property. National Wetland Invento ii .. 3.2 Topography The site varies in elevation with high points along the western and eastern property boundary. A low depressional draw near the center of the property extends from the southern property boundary to the northern property boundary. I I I I I I I I I I I I I I I I I I I 3.3 Uplands Re: Johnseine Property SWC Job# A6-209 October 10, 2006 Page6of8 The upland portion of the site is typical of disturbed urban areas sites. The western portion of the property appears to have been historically cleared and graded in association with the existing single family residence. The eastern portion of the property has a deciduous forested canopy predominantly comprised of red alder (A/nus rubra) with a shrub underbrush dominanted by Himalayan blackberry (Rubus armeniacus). Other species located within the upland areas include beaked hazelnut (Cory/us comuta), red elderberry (Sambucus racemosa), holly (llex sp.), and snowberry (Symphoricarpos a/bus), Soil pits excavated within the upland areas of the site generally revealed a 16-inch layer of gravelly, silt loam. Two recorded data points within upland areas revealed colors of lOYR 3/6 and lOYR 4/3. These areas were dry within 16-inches of the soil surface during the time of our field investigation. 3.4 Wetland A/B Wetland A/B was flagged with pink "Wetland Delineation" flagging labeled A-1 through A-12 (western wetland edge) and B-1 through B-14 (eastern wetland edge.) Wetland A/B is located near the center of the property and extend off-site to the north of the property and to the south of the property. Wetland A/B is a scrub-shrub and emergent wetland located near the center of the property. Although there are some tree species located within the wetland there are not enough trees greater than 20-feet tall to comprise a forested wetland class. Dominant vegetation within Wetland A/B includes black cottonwood (Populus balsamifera), red alder (A/nus rubra), salmonberry (Rubus spectabilis), hard hack (Spiraea douglasiz), Himalayan blackberry (Rubus armeniacus), reed canary grass (Phalaris arundinacea), manna grass (Glyceria elata), skunk cabbage (Lysichitum americanum), soft rush (Juncus effesus), and buttercup (Ranunculus repens). Soil pits excavated within the wetland revealed a silt loam A-horizon with a color of I OYR 2/1; an underlying sandy, silt loam B-horizon revealed a color of SY 5/2. Soils within the wetland were typically saturated within 12-inches of the soil surface during the time of our site visit. According to the United States Fish and Wildlife Service (USFWS) wetland classification method (Cowardin et al. 1979), Wetland A/B would be considered a PSSIC (palustrine, scrub-shrub, broad-leaved deciduous, seasonally flooded), and PEMI C (palustrine, emergent, persistent, seasonally flooded) wetland. According to the King County Code (KCC §21A.24.380), Wetland A/B would be considered a Category 3 wetland based on an overall score of 46 (Water Quality 22, Hydrologic 7, Habitat 17) on the adopted Department of Ecology Wetland Rating Form for Western Washington. Typically, Category 3 wetlands with habitat scores less than 20 points and located within the urban growth area have 75-foot buffer measured from the wetland edge. A 15-foot building setback line (BSBL) is measured from the buffer edge. I I I I I I I I I I I I I I I I I I I I Re: Johnseine Property SWC Job# A6-209 October l 0, 2006 Page 7 of8 Wetlands located within the urban growth area may receive a 25-foot buffer reduction if all criteria pursuant to §21A.24.325 are followed. According to the City of Renton Municipal Code (RMC §4-3-050(B)(7)), Wetland A/B would be considered a Category 2 wetland due to is size being greater than 2,200sf and not being classified as a Category 1 or Category 3 wetland. Typically, Category 2 wetlands have a 50-foot buffer measured from the wetland edge (RMC§4-3-050(M)(6). 3.6 Wildlife and Habitat per Renton Study Requirements Research for wildlife species included field investigations and research of the Washington Fish and Wildlife habitat inventories. The site can be broken into two distinct vegetative communities based on the site visit and review of the aerial photographs provided by King County I-map and the City of Renton 2003 aerial photo. (Note: these sketches are not to scale and do not represent surveys of the mapped vegetative communities.) I I I I I I I I I I I I I I I I I I Re: Johnseine Property SWC Job# A6-209 October l 0, 2006 Page 8 of8 No threatened or endangered species were observed during the time of our site visits. Likewise, no identifiable visual signs of any endangered or threatened species were observed on the property. A search of the Washington Department of Fish and Wildlife Habitat and Species Map for King County and Vicinity did not reveal any Endangered, Threatened or Sensitive species located on or near the site. The inventory does reveal a State Candidate Species site located approximately 2 miles to the northeast of the site. 4.0 Proposed Project The proposed project is a single family subdivision. Under the King County Code the project has been designed to avoid impacts to the wetland and its associated buffer by utilizing the mitigation measures set forth by §21A.24.325. Therefore, with the 25-foot buffer reduction the project will avoid impacts to the critical area. Upon acceptance of the conceptual mitigation plans, a final mitigation plan will detail the plant species, size, location, monitoring requirements of any degraded area within the reduced wetland buffer. Under the Renton Municipal Code the proposed project will avoid impacts to the wetland and its associated buffer. If you have any questions or need any additional information please contact our office at 253.859.0515 or by e-mail at awill@sewallwc.com. Sincerely, Sewall Wetland Consulting, Inc. J. Aaron Will Wetland Scientist File:A5~209 Johnseine Property wa.doc I I I I I I I I I I I I I I I I I I I .•... , £sago ·aN'BOi ···--· tso90 ·oN'OO; ,' ..... , £8090 ·oNOO; ..... , £Soso ·oN'SOf I I I' I I I I I I ,I I ,I I I I I I I I .0••.L E:8090 ·o~r;o; •••• ! &so9o ·0N'8°0·r 'I I I 'i; I ~;;, , ,.,-_ - !I.iii ,;l!i _ li1D!J_ \~ ~ 1 ; ~ ·31{ ·:iw oos~;d===:--=---=-===--=--------- 11 1li,. ,,j -, • - I -·'•; '' ' i• , I "• . , -, '' ' ls!n ,,,1i •i•i Ii' 1 ,,. I· -i, 1 ---'J~ I ,.. i~~~ if1~,' ~1~r I \:~·11 I ~.,~a 1·~~~. i I i , ---=-, , ,, · ,,·,'I ,; . ,, , ,i,,• I 1;i• I " ' ~--,.,__J/.,,' '.\1 I! I! L' I ,1jji ' ,,i,;1 I I I • • , · ., _ .-.:·· . .... -; • 1,,i,,'•;l ,. I !tia ti , ,_ , '-I ' , ,· ~," ' , . • t I ;, I ; T~ ;> ,:7-rr i;.1 . , ' •'';·, I -' ,•' I'' I r--r 'll ' ' " . ' .. ' . ' ,, . . . ff . I i 1'ii f of,. ,f --· . · \•~~~ r/~J'.,j 1 " 1 . / .. !li ; ,\ ~'-1,. -~ / \ ' ,,,------1 ~t ---· \./ i~,. ~,-----/~-/ . ----- /1• :'·' ', J,d---;~ , ' /'+-.J, ,o ; -•' ' I\ . \ h~."-~'/ ---".,:.:.:··J._ J., I, t \ v-/·-,"" 1., , ,i,! ,(,;: _ l '-=,, ;~:::_ -,_! '~ -'; ! j. ,; ;i•, 11 1·1 /''-,-_.._, ,.·--,,,,,!!! 'I ' .'· ' I <7 --== !,;j. /i :~;._.,..:..;. /-,,m: , , ,--__ ,,.~~ , , -. -,. ,i11• 1 -., j•/ ' ,v-/ "'" --.. . " " -_,. ..--A it; , ;~ 11 r,· 111·m:i1t1. ? ~~ u_.l Ii) Ii) ..__ i,~f~i ' ~ -'• • 'I ...a:e!'!1.L/ ',.· ~~ ;~, .. -' I .. • ",,<1 / , -.· --"/ . /' • •I'· ,; i••j ~,) ,ff:'': <.if:' ,; ·' ; . ~r~;,~; I m!: I ur . , 2;;,-. 1 .,. · 1 : iih-, ; ,:,--·--, ... , : I I I \.· .,I \\_~./, . , "', ',·,'11·, J::-11,L . ! . • -···,. __ ,·c_r,.., .. ~,,.1, -I ;, ---.-----.,. -' ' ' ' ' ii'' i,' .. \ ,. " '. c' r· -,!, u1-' ''" ,:: . :. . . • . 1,c I , J,:,, ' ---' -- !Ill \ ' . ' g '', ~---' ' f l(J, ' 11 11 '!(i I I -·~-. ,, """ ,,,., I =t-----i, · ,~ ;=~:__ . -if ·'. ; .:. ,,,,. I z;-., . ~-,, -,. ., "' '" I I ·~, ~~loc,:!'"!f.~~ "~ -. _:--::=::-:=---~ H ;1 .. , ''i: 111; + ~ ,0>•.I Eaoeo ·oN'El"Of .O••., £SOso ·oN'SOr I I I ',.,. i I ., I I I I I I I I I I I I ROUTINE WETLAND DETERMINATION DATA FORM (Washington State Wetlands Identification & Delineation Manual, 1997) B-12 WETLAND CONSULTING, INC. 1103 West Meeker Street Kent, Washington 98032 (253) 859-0515 Project Name/#: Singh -Stillwater ProJlefil Date: 8-3-06 Investigator: Aaron Will Data Point: L Jurisdiction: King County State: WA Amica! Analysis: IE!.ii Problem Area: ~ VEGETATION Dominant plant species Stratum Indicator Coverage% 1. /., l;Ji,;, S A (....-1 ( f'1 ,\,-l, ,J"";> ~/$ t:'1:C&\ 2.,/IAV) l'V~r,----;- 3. s,,, ',, ,:;, 5 C Qe JI,-.,. -f' F A-C,:1.A 4. ·rf,, -r ,I fl< ,_ 5. 6. 7. 8. 9. 10. % of species OBL, FACW and/or FAC: ~ 39. Hydrophytic vegetation criteria met: Yes~ Marginal Comments: SOILS Mapped Soil Series: Alderwood On Hydric Soils List?: Yes IE!.ii Drainage Class: moderately well drained Depth(O in) Matrix color Redox concentration color Texture _liin. LQtJl.. '!,/~ 8"'"'''~ i.' >+ la.,~ in. -in. - in. -Organic soil_, Histic epipedon_, Hydrogen sulfide__, gleyed_, redox concentrations_, redox depletions_, pore linings_. iron concretions_, manganese concretions_, organic matter in surface horizon (sandy soil)_, organic streaking (sandy soils)_, organic pan (sandy soil)_. II,'§~ C."' £c.~ ,;v,.. c...._ Hydric soil criteria met: Yes Jy@' Basis: Comments: HYDROLOGY Recorded data~ inundation , saturation , watermarks ___ , drift lines_, sediment deposits___, drainage patterns . Wetland hydrology criteria met: Yes~ Basis: p,.., Comments: fJ SUMMARY OF CRITERIA Soil Temp. at 19.7" depth: Growing Season?:~ Hydrophytic vegetation:..Y@ Hydric soils:_ym?',Vetland hydrology: YilJ) Data point meets the criteria of a jurisdictional wetland?: Yes ~ ,. I I I I I I I I I I I ,I I I I I I ROUTINE WETLAND DETERMINATION DATA FORM (Washington State Wetlands Identification & Delineation Manual, 1997) B-12 WETLAND CONSULTING, INC. 1103 West Meeker Street Kent, Washington 98032 (253) 859-0515 Project Name/#: Singh· Stillwater Pro11em Date: 8-3-06 Investigator: Aaron Will Data Point: Q_ Jurisdiction: King County State: WA Atypical Analysis: ~ Problem Area: ~ VEGETATION Dominant plant species Stratum Indicator Coverage% 1. tf..lf; ,,,!£h-. [.i'bi!!.." fe (51,,.,,._....., I+ tu. I- ' ~I /J. t;:e-,i ... 6) }ll s ~,t,S hfe-t-2. ~,S-z 3. &,, ..,...,..~ ' t&. itJ~/.v-,.,, 'f.,1:_(,_ IA lt: 4. 5. 6. 7. 8. 9. IO. % of species OBL, FACW and/or FAC: "'7 % Hydrophytic vegetation criteria met: @No Marginal Comments: SOILS Mapped Soil Series: Alderwood On Hydric Soils List?: Yes ~ Drainage Class: moderately well drained Depth(O in) Matrix color Redox concentration color Texture _l_'.'Lin. IO HL ~/I <,·H J,..,.,_ 1!,_in. ~I:'. ', / ',. {',..,. ....it),,,......_ a.~,1-)...._e+-,.. "'.ia r_;lt I ge; ""' in. - m. Organic soil_, Histic epipedon_, Hydrogen sulfide_, gleyed_, redox concentrations.!£ redox depletions_, pore linings_, iron concretions_, manganese concretions_, organic matter in surface horizon (sandy soil)_, organic streaking (sandy soils)_. organic pan (sandy soil)_. Hydric soil criteria met@No Basis: Comments: HYDROLOGY Recorded data -, inundation , saturation ,r , watermarks~ drift lines ___ , sediment deposits~ drainage patterns . t"'I " :•)-$ -+.,J.._'+-eJ Wetland hydrology criteria met$ No Basis: -'> Comments: SUMMARY OF CRITERIA Soil Temp. at 19.7" dep~ Growing Season?:&fil Hydrophytic vegetation:__ili Hydric soils:~Wetland hydrologytzili Data point meets the criteria of a jurisdictional wetland?: ~ No I I I I I I I I I I I J, I i I I I ROUTINE WETLAND DETERMINATION DATA FORM (Washington State Wetlands Identification & Delineation Manual, 1997) B-12 WETLAND CONSULTING, INC. 1103 West Meeker Sueet Kent, Washington 98032 (253) 859-0515 Project Name/#: Singh -Stillwater Pro2em Date: 8-3-06 Investigator: Aaron Will Data Point: ~ Jurisdiction: King County State: WA Atypical Analysis: ~ Problem Area: ~ VEGETATION Dominant plant species Stratum Indicator Coverage% }. i1l~ll:.i ~L~.t!.o 1'6 C. ll~ Sl~ FAI'. !:1 2. J.I · .u!. ('" \.., f "'--r F-_,U 3. _,.,a~ ~· 51<: NZ. 4. 5. 6. 7. 8. 9. 10. % of species OBL, FACW and/or PAC: ',C 9A Hydrophytic vegetation criteria met: Yes~ Comments: SOILS Mapped Soil Series: Alderwood On Hydric Soils List?: Yes ~ Drainage Class: moderately well drained Depth(O in) Matrix color Redox concentration color Texture L£in. !Df K. '113 ~,.~,1~ s: !+ fo,,..,..,......... m. - in. - _in. Organic soil_, Histic epipedon_, Hydrogen sulfide_, gleyed_, redox concentrations_, redox depletions_, pore linings_. iron concretions_, manganese concretions_, organic matter in surface horizon (sandy soil)_, organic streaking {sandy soils)_, organic pan (sandy soil)_. Hydric soil criteria met: Yes@ Basis: l:1.,a1,.,. i:;:.1,.," Qv""-~ Comments: HYDROLOGY Recorded data _, inundation . saturation , watermarks ___ , drift lines ___ , sediment deposits ___ , drainage patterns . [")" ... Wetland hydrology criteria met: Yes @ Basis: Comments: 0 SUMMARY OF CRITERIA Soil Temp. at 19.7" depth: Growing Season?: !11/IN Hydrophytlc vegetat10n:~ Hydric soils:~ etland hydrology: Y1fP Data point meets the criteria of a jurisdictional wetland?: Yes l'fE> I ,. WETLAND RATING FORM-WESTERN WASHINGTON Name of wetland (if known): Wetland A/B -Johnseine Property Location: SEC: __ _ TWNSHP: RNGE: __ _ (attach map with outline of wetland to rating form) I Person(s) Rating Wetland: Aaron Will Affiliation: Sewall Wetland Consulting, Inc. Date of site visit: 8-3-06 '· I I I I I I I i •• I I I I I I I SUMMARY OF RATING Category based on FUNCTIONS provided by wetland I II III IV Category I= Score> 70 Score for Water Quality Functions Category II = Score 51 -69 Score for Hydro logic Functions Category III = Score 30 -50 Score for Habitat Functions Category IV = Score< 30 TOT AL Score for Functions Category based on SPECIAL CHARACTERISTCS of Wetland I II --Does not apply Final Category (choose the "highest" category from above") Check the appropnate type and class of wetland bemg rated. ~~g~7;;~Wit_rana~1;voe·Ip1:i~~,.,i1L · :i1r;YfJ.l ~~f'" ~·. "--'lo'.!1•·· .... ~~Sl<')' ';":!"'''~, "''-'i!tl'"~• 1:i1,Wetlanili€·IPs$Jt'i~~·-fi~--:.ll: ~,..l'lfi\~ Estuarine Denressional X Natural Herita!!e Wetland Riverine Boe Lake-frinee Mature Forest Slone Old Growth Forest Flats Coastal Laeoon Freshwater Tidal Interdunal None of the above SP 1. Has the wetland been documented as a habitat for any Federally listed Threatened or Endangered plant or animal species (TIE species)? For the purposes of this rating system, "documented" means the wetland is on the appropriate state or federal database. SP2. Has the wetland been documented as habitat for any State listed Threatened or Endangered plant or animal species? For the purposes of this rating system, "documented" means the wetland is on the a ro riate state database. SP3. Does the wetland contain individuals o Priori/ s ecies listed b the WDFW or the state? SP4. Does the wetland have a local significance in addition to its functions? For example, the wetland has been identified in the Shoreline Master Program, the Critical Areas Ordinance, or in a local mana ement Ian as havin s ecial si nificance. 22 7 17 46 To complete the next part of the data sheet you will need to determine the Hydrogeomorphic Class of the wetland being rated. 3 The hydrogeomorphic classification groups wetlands in to those that function in similar ways. This simplifies the questions needed to answer how well the wetland functions. The Hydrogeomorphic Class of a wetland can be determined using the key below. Seep. 24 for more detailed instructions on classifying wetlands. We:thmti Ratimr Fann-western Washimzton (11/04) Page I of8 I I I I I I I I I I I I I I I I Wetland Name: Classification of Vegetated Wetlands for Western Washington Date: 1. Are the water levels in the wetland usually controlled by tides (i.e. except during floods)? lill2]-go to 2 YES -the wetland class is Tidal Fringe If yes, is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? YES -Freshwater Tidal Fringe NO -Saltwater Tidal Fringe (Estuarine) If your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. If it is a Saltwater Tidal Fringe it is rated as an Estuarine wetland. Wetlands that were call estuarine in the first and second editions of the rating system are called Salt Water Tidal Fringe in the Hydrogeomorphic Classification. Estuarine wetlands were categorized separately in the earlier editions, and this separation is being kept in this revision. To maintain consistency between editions, the term "Estuarine" wetland is kept. Please note, however, that the characteristics that define Category I and II estuarine wetlands have changed (see p. __ ). 2. Is the topography within the wetland flat and precipitation is only source (>90%) of water to it. lill2]-go to 3 YES -The wetland class is Flats If your wetland can be classified as a "Flats" wetland, use the form for Depressional wetlands. 3. Does the wetland meet both of the following criteria? ___ The vegetated part of the wetland is on the shores of a body of open water (without any vegetation on the surface) where at least 20 acres (Sha) are permanently inundated (ponded or flooded); At least 30% of the open water area is deeper than 6.6 (2 m)? ~l@_j---o~-g-o-to-4 YES -The wetland class is Lake-fringe (Lacustrine Fringe) 4. Does the wetland meet all of the following criteria? 5. 6. 7. 8. ___ The wetland is on a slope (slope can be very gradual). ___ The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetfl.ow, or in a swale without distinct banks. ___ The water leaves the wetland without being Impounded? NOTE: Surface water does not pond in these types a/wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <3 ft diameter and less than 1 foot deep). lill2]-go to 5 YES -The wetland class is Slope Is the wetland in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river? The flooding should occur at least once every two years, on the average, to answer "yes". The wetland can contain depressions that are filled with water when the river is not flooding. lill2]-go to 6 YES -The wetland class is Riverine Is the wetland in a topographic depression in which water ponds, or is saturated to the surface, at some time of the year. This means that any outlet, if present is higher than the interior of the wetland. NO -go to 7 ~ -The wetland class is Depressional Is the wetland located in a very flat area with no obvious depressional and no stream or river running through it and providing water. The wetland seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. No-goto8 YES -The wetland class is Depressional Your wetland seems to be difficult to classify. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a depressional wetland has a zone of flooding along its sides. Sometimes we find characteristics of several different hydrogeomorphic classes within one wetland boundary. Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within your wetland. NOTE: Use this table only if the class that is recommended in the second column represents l 0% or more of the total area of the wetland being rated. If the area of the second class is less than I 0% classify the wetland using the first class. :rt'H'OMiCiiffs~s)W#hi11!iit&e"l11t'ffiieUfw.~J1ari'J/!JJ?u'ii"iliiiyJ.,;;; ~i5u;1Z1~1If:'!'.'t~\:nt~~G.f(!.~$i'tb'.fU~·etl1iitR'iifilfilt:-s:.t;~~~~¥~1,tftt,~l~iI;";'"~~·1i Slope + Riverine Riverine Slooe + Deoressional Deoressional Slope+ Lake-fringe Lake-fringe Depressional + Riverine along stream within boundary Depressional Deoressional + Lake-fringe Deoressional Salt Water Tidal Fringe and any other class of Treat as ESTUARINE under wetlands with special freshwater wetland characteristics If you are unable still to determme which of the above cntena apply to your wetland, or you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. We;tlanrl RatinP Fonn-we.<:tem WashinP-ton (11/04) Paee 2 of8 I ,, I I I I I I I I I I I II II I • I Does the wetland have the potential to improve water quality? (see p.38) D 1. l Characteristics of surface water flows out of the wetland: • Wetland is a depression with no surface water outlet ............................................................ points= 3 • Wetland has an intermittently flowing, or highly constricted, outlet.. ................................... points= gj • Wetland has an unconstricted surface outlet ......................................................................... points= I • Wetland is flat and has no obvious outlet and/or outlet is a ditch .......................................... oints = I D 1.2 The soil 2 inches below the surface is clay, organic, or smells anoxic (hydrogen sulfide or rotten eggs). YES oints = NO oints = 0 D 1.3 Characteristics of persistent vegetation (emergent, shrub, and/or forest class): • Wetland has persistent, ungrazed vegetation>= 95% of area ............................................... points= 5 • Wetland has persistent, ungrazed vegetation>=~ of area .................................................. points= Q] • Wetland has persistent, ungrazed vegetation > = l/10 of area ............................................... points= I • Wetland has ersistent un razed ve etation < 1/10 of area .................................................. oints = 0 D 1.4 Characteristics o seasonal ponding or inundation: T is is the area o the wetland that is ponded or at least 2 months, but dries out sometime during the year. Do not count the area that is permanent y ponded. Estimate area as the average condition 5 out of JO years. NOTE: See textjor indicators of seasonal and permanent inundation. , Area seasonally ponded is> 1/2 total area of wetland ........................................................... points= 4 Area seasonally ponded is> 1/4 total area of wetland .......................................................... points= g) Area seasonall anded is< 1/4 total area of wetland ........................................................... oints = 0 Total for D 1 Add the oints in the boxes above D 2 Does the wetland have the opportunity to improve water quality? (seep. 44) Answer YES if you know or believe there are pollutants in groundwater or surface water coming into the wetland that would otherwise reduce water quality in streams, lakes or groundwater downgradient from the wetland? Note which of the following conditions provide the sources of pollutants. Grazing in the wetland or within 150 ft Untreated stormwater discharges to wetland Tilled fields or orchards within 150 ft. of wetland A stream or culvert discharges into wetland that drains developed areas, residential areas, farmed fields, roads, or clear-cut logging _x_ Residential, urban areas, golf courses are within 150 ft. of wetland Wetland is fed by groundwater high in phosphorus or nitrogen Other YES multi lier is 2 2 4 3 2 11 Multiplier 2 ,;o:XVJM¥>bR:or.:o~re;pt!JN0Tio!'ls·.u rndiciitar,~lli~t,w.etlan'a:Juii'ctioiis,10•,redu,r.M10·0a,n'··,aifd\sireairi 'ae · ·,~iitioii:''1:,;;,;:.'·· J\it4:"iJ, D 3 Does the wetland have the potential to reduce flooding and erosion? (see p.46) ~?,?::f:;~~~1t~J:'.~·t\ D 3.1 Characteristics of surface water flows out of the wetland: • Wetland has no surface water outlet ..................................................................................... points= 4 • Wetland has an intermittently flowing, or highly constricted, outlet ..................................... points= gj • Wetland is flat and has no obvious outlet and/or outlet is a small ditch ................................. points= 1 • Wetland has an unconstricted surface outlet ......................................................................... oints = 0 D 3.2 Depth of storage during wet periods. Estimate the height of ponding above the bottom of the outlet. • Marks of ponding are 3 ft. or more above the surface ........................................................... points= 7 • The wetland is a "headwater wetland" .................................................................................. points= 5 Marks of ponding between 2 ft. to< 3 ft. from surface ......................................................... points= 5 • Marks are at least 0.5 ft. to< 2 ft. from surface ................................................................... points= rn • Wetland is flat but has small depressions on the surface that trap water ................................ points= 1 • Marks of ondin less than 0.5 ft.. ........................................................................................ oints = 0 D 3.3 Contnbution of wetland to storage in the watershed: Estimate the ratio o upstream basm contributing surface water to the wetland to the area of the wetland itself. • The area of the basin is less than IO times the are of wetland ................................................ points -5 • The area of the basin is l O to I 00 times the area of the wetland ........................................... points -IJI The area of the basin is more than 100 times the area of the wetland .................................... points= 0 • Wetland is in the FLATS class basin= the wetland b definition ...................................... oints = 5 Total for D 3 Add the oints in the boxes above D 4 Does the wetland have the opportunity to reduce flooding and erosion? (seep. 49) Answer YES if the wetland is in a location in the watershed where the flood storage, or reduction in water velocity, it provides helps protect downstream property and aquatic resources from flooding or excessive and/or erosive flows. Answer NO if the water coming into the wetland is controlled by a structure such as flood gate, tide gate, flap valve, reservoir etc. OR you estimate that more than 90% of the water in the wetland is from groundwater. Note which of the following indicators of opportunity apply. Wetland is in a headwater of a river or stream that has flooding problems. Wetland drains to a river or stream that has flooding problems Wetland has no outlet and impounds surface runoff water that might otherwise flow into a river or stream that has flooding problems Other------,-----------.,-.,...,.,.-,-,-------------- YES multi lier is 2 0 TOTAL -H drolo ic Functions Multi the score from D3 by D4; then add score to table on . 1 Wetland Rating Fonn-western Washington (11/04) 2 2 3 7 Multiplier 1 7 Page 3 ofS I I I I I I I I I I I I I I I, I I I I H I Does the wetland have the potential to provide habitat for many species? H I. I Vegetation structure (see P. 73): Check the types of vegetation classes present (as defined by Cowardin) if the class covers more than 10% of the area of the wetland or 114 acre. Aquatic Bed _x _ Emergent plants _x_ Scrub/shrub (areas where shrubs have> 30% cover) _x_ Forested (areas where trees have> 30% cover) __ Forested areas have 3 out of 5 strata (canopy, sub-canopy, shrubs, herbaceous, moss/ground-cover) Add the number of vegetation types that qualify. If you have: 4 types or more ... points = 4 3 types .. points = if] · 2 t es ........... ..... oints = 1 1 t e .... oints = 0 H 1.2 Hydroperiods (seep. 74): Check the types of water regimes (hydroperiods) present within the wetland. The water regime has to cover more than 10% of the wetland or 1/4 acre to count (see text/or descriptions ofhydroperiods). Permanently flooded or inundated _x_ Seasonally flooded or.inundated 4 or more types present ..... points= 3 _x_ Occasionally flooded or inundated 3 types present .................. points= If] x __ Saturated only 2 types present .................. points= 1 Permanently flowing stream or river in, or adjacent to, the wetland Seasonally flowing stream in, or adjacent to, the wetland Lake-fringe wetland ................. = 2 points Freshwater tidal wetland .......... = 2 points H 1.3 Richness of Plant Species (seep. 76): Count the number of plant species in the wetland that cover at least 10 ft2 (different patches of the same species can be combined to meet the size threshold) You do not have to name the species. Do not include Eurasian Mi/foil, reed canarygrass, purple /oosestrife, Canadian Thistle. If you counted: > 19 species ....................... points= 2 5 -19 species .................... points=[] List species below (optional): < 5 species ......................... points = 0 H 1.4 Interspersion of Habitats (seep. 77): Decided from the diagrams below whether interspersion between types of vegetation (described in Hl .1), or vegetation types and unvegetated areas (can include open water or mudflats) is high, medium, low, or none. None=.() points Low~ 1 point Moderate=· 2 points [riparian braided channels] High = 3 points Note: If you have 4 or more vegetation types or 3 vegetation types and open water, the rating is always "hi h". H 1.5 Special Habitat Features (seep. 78): Check the habitat features that are present in the wetland. The number of checks is the number of points you put into the next column. _x_ Large, downed, woody debris within the wetland(> 4 in. diameter and 6 ft. long) _x_ Standing snags (diameter at the bottom> 4 inches) in the wetland Undercut banks are present for at least 6.6 ft. (2m) and/or overhanging vegetation extends at least 3 .3 ft. ( 1 m) over a stream for at least 33 ft. (I Om) Stable steep banks of fine material that might be used by beaver or muskrat for denning (> 30 degree slope) OR signs of recent beaver activity are present At least 1/4 acre of thin-stemmed persistent vegetation or woody branches are present in areas that are permanently or seasonally inundated (structures for egg-laying by amphibians) _x_ Invasive plants cover less than 25% of the wetland area in each stratum of plants Add the oints in the column above ,u .. tl.,nrl R<>tina Pnrm -mPdPrn W::i.::hinotnn (11 /f'lA\ 2 2 2 3 10 Pa~e 4 of 8 I I I I I I I I I I I I I I I I I I I H2 Does the wetland have the opportunity to provide habitat for many species? H 2.1 Buffers (see P. 81): Choose the description that best represents condition of buffer of wetland. The highest scoring criterion that applies to the wetland is to be used in the rating. See text for definition of "undisturbed". __ 1 OOm (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > 95% of circumference. No developed areas within undisturbed part of buffer (relatively undisturbed also means no grazing) .......................................................... points = 5 __ IOOm (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > 50o/o circumference .................................................................................................... points= 4 __ 50m (170 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > 95% circumference .................................................................................................... points= 4 __ lOOm (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > 25o/o circumference .................................................................................................... points= 3 _x_ 50m (170 ft) of relatively undisturbed vegetated areas, rocky areas, or open water for> 50% circumference ............................................................................................... points -0 If buffer does not meet any of the three criteria above: __ No paved areas (except paved trails) or buildings within 25m (80 ft) of wetland> 95% circumference. Light to moderate grazing or lawns are OK ................................... points= 2 __ No paved areas of buildings within 50m of wetland for> 50% circumference. Light to moderate grazing or lawns are OK ................................................................... points = 2 __ Heavy grazing in buffer ................................................................................................. points= 1 __ Vegetated buffers are< 2m wide (6.6 ft) for more than 95% circumference (e.g. tilled fields, paving, basalt bedrock extend to edge of wetland) ............................. points= 0 __ Buffer does not meet any of the criteria above ............................................................... points = 1 H 2.2 Corridors and Connections (seep. 82) H 2.2.1 Is the wetland part of a relatively undisturbed and unbroken vegetated corridor (either riparian or upland) that is at least 150 ft. wide, has at least a 30% cover of shrubs, forest or native undisturbed prairie, that connects to estuaries, other wetlands or undisturbed uplands that are at least 250 acres in size? (Dams in riparian corridors, heavily used gravel roads, paved roads, are considered breaks in the corridor). YES= 4 points (go to H 2.3) NO= go to H 2.2.2 H. 2.2.2 Is the wetland part ofa relatively undisturbed and unbroken vegetated corridor (either riparian or upland) that is at least 50 ft. wide, has at least 30% cover of shrubs or forest, and connects to estuaries, other wetlands or undisturbed uplands that are at least 25 acres in size? OR a lake· fringe wetland, if it does not have an undisturbed corridor as in the question above? YES= 2 points (go to H 2.3) NO= go to H 2.2.3 H. 2.2.3 Is the wetland: • Within 5 mi (8km) of a brackish or salt water estuary OR • Within 3 miles of a large field or pasture(> 40 acres) OR • Within 1 mile of a lake greater than 20 acres? YES=~ NO=~ 3 0 I -I I I I I I I I I I I I I I I I I I ¢ H 2.3 Near or adjacent to other priority habitats listed by WDFW (seep. 83): Which of the following priority habitats are within 330 ft. (100m) of the wetland? (See text for a more detailed description of these priority habitats.) _x_ Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. Aspen Stands: Pure or mixed stands of aspen greater than 0.8 ha (2 acres) Cliffs: Greater than 7.6m (25 ft) high and occurring below 5000 ft. Oldwgrowth forests: (Old growth west of Cascade Crest) Stands of at least 2 tree species, forming a multiw!ayered canopy with occasional small openings, with at least 20 trees/ha (8 trees/acre)> 81cm (32 in) dbh or> 200 years ofage. Mature forests: Stands with average diameters exceeding 53cm (21 in) dbh; crown cover may be less than I 00%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth; 80 -200 years old west of the Cascade Crest. Prairies: Relatively undisturbed areas (as indicated by dominance of native plants) where greases and/or forbs form the natural climax plant community. Talus: Homogenous areas of rock rubble ranging in average size 0.15 -2.0m (0.5 -6.5 ft), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. be associated with cliffs. Caves: A naturally occurring cavity, recess, void, or system of interconnected passages. Oregon white Oak: Woodlands stands of pure oak or oak/conifer associations where canopy coverage of the oak component of the stand is 25%. May Urban Natural Open Space: A priority species resides within or is adjacent to the open space and uses it for breeding and/or regular feeding; and/or the open space functions as a corridor connecting other priority habitats, especially those that would otherwise be isolated; and/or the open space is an isolated remnant of natural habitat larger than 4 ha (IO acres) and is surrounded by urban development. Estuary/Estuary-like: Deepwater tidal habitats and adjacent tidal wetlands, usually semi-enclosed by land but with open, partly obstructed or sporadic access to the open ocean, and in which ocean water is at least occasionally diluted by freshwater runoff from the land. The salinity may be periodically increased above that of the open ocean by evaporation. Along some low-energy coastlines there is appreciable dilution of sea water. Estuarine habitat extends upstream and landward to where ocean-derived salts measure less than 0.5 ppt. during the period of average annual low flow. Includes both estuaries and lagoons. Marine/Estuarine Shorelines: Shorelines include the intertidal and subtidal zones of beaches, and may also include the backshore and adjacent components of the terrestrial landscape (e.g., cliffs, snags, mature trees, dunes, meadows) that are important to shoreline associated fish and wildlife and that contribute to shoreline function (e.g., sand/rock/log recruitment, nutrient contribution, erosion control). If wetland has 3 or more priority habitats.= 4 points If wetland has 1 priority habit ... = [1 point! If wetland has 2 priority habitats .............. = 3 noints No habitats ............................... = 0 points H 2 .4 Wetland Landscape: Choose the one description of the landscape around the wetland that best fits (seep. 85) • There are at least 3 other wetlands within 1/2 mile, and the connections between them are relatively undisturbed (light grazing between wetlands OK, as is lake shore with some boating, but connections should NOT be bisected by paved roads, fill, fields, or other development ....................................................................................................................... points = 5 • The wetland is Lake-fringe on a lake with little disturbance and there are 3 other lake-fringe wetlands within 1/2 mile ..................................................................................................... points= 5 • There are at least 3 other wetlands within 1/2 mile, BUT the connections between them are disturbed ............................................................................................................................. points = ~ • The wetland fringe on a lake with disturbance and there are 3 other lake-fringe wetlands within 1/2 mile .................................................................................................................... points= 3 • There is at least I wetland within 1/2 mile ........................................................................... points = 2 • There are no wetlands within 1/2 mile ................................................................................. noints = 0 H 2 TOTAL Score -opportunity for providing habitat Add the scores in the columns above Total Score for Habitat Functions Add the points for H I and H 2; then record the result on p. 1 3 7 17 I I I I I I I I I I I I I I I SC2 SC3 CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Please determine if the wetland meets the attributes described below and circle the appropriate answers and Category. YES = Category I NO= go to SC l.2 SC 1.2 Is the wetland at least 1 acre in size and meets at least two of the following conditions? YES = Category I NO = Category II __ The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than l 0% cover of non-native plant species. If the non-native Spartina spp,. are only species that cover more than I 0% of the wetland, then the wetland should be given a dual rating (I/II). The area of Spartina would be rated a Category II while the relatively undisturbed upper marsh with native species would be a Category l. Do not, however, exclude the area of Spartin a in determining the size threshold of 1 acre. __ At least 3/4 of the landward edge of the wetland has a I 00 ft. buffer of shrub, forest, or un-grazed or un-mowed grassland __ The wetland has at least 2 of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. Natural Heritage Wetlands (seep. 88) Natural Heritage wetlands have been identified by the Washington Natural heritage Program/DNR as either high quality undisturbed wetlands or wetlands that support state Threatened, Endangered, or Sensitive plant species. SC 2.1 Is the wetland being rated in a Section/Township/Range that contains a natural heritage wetland? (This question is used to screen out most sites before you need to contact WNHPIDNR.) S/T/R information from Appendix D or accessed from WNHP/DNR web site __ _ YES __ Contact WNHP/DNR (seep. 88) and go to SC 2.2 NO __ _ SC 2.2 Has DNR identified the wetland as a high quality undisturbed wetland or as a site with state threatened or endangered plant species? YES = Category 1 NO Bogs (seep. 88) Does the wetland (or part of the wetland) meet both the criteria for soils and vegetation in bogs? Use the key below to identify if the wetland is a bog. If you answer yes you will still need to rate the wetland based on its function. I. Does the wetland have organic soil horizons (i.e. layers of organic soil), either peats or mucks, that compose 16 inches or more of the first 32 inches of soi] profile? (See Appendix B for a field key to identify organic soils)? YES= go to question 3 NO= go to question 2 2. Does the wetland have organic soils, either peats or mucks that are less than 16 inches deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on a lake or pond? YES= go to question 3 NO= is not a bog for purpose of rating 3. Does the wetland have more than 70% cover of mosses at ground level, AND other plants, if present, consist of the "bog" species listed in Table 3 as a significant component of the vegetation (more than 30% of the total shrub and herbaceous cover consists of species in Table 3)? YES = Is a bog for purpose of rating NO = go to question 4 NOTE: If you are uncertain about the extent of mosses in the understory you may substitute that criterion by measuring the pH of the water that seeps into a hold dug at least 16" deep. If the pH is less than 5.0 and the "bog" plant species in Table 3 are present, the wetland is a bog. 4. Is the wetland forested(> 30% cover) with sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Englemann's spruce, or western white pine. WITH any of the species (or combination of species) on the bog species plant list in Table 3 as a significant component of the ground cover(> 30% coverage of the total shrub/herbaceous cover)? YES= Category I NO= Is not a bog for purpose of rating Cat. I Cat. II Dual Rating I/II Cat I Cat. I P:ure 7 of 8 I I I I I I I I I I I I I I I I I I SC4 Forested Wetlands (seep. 96) Does the wetland have at least I acre of forest that meet one of these criteria for the Department of Fish and Wildlife's forests as priority habitats?. If you answer yes you will still need to rate the wetland based on its function. __ Old-growth forests: (west of Cascade Crest) Stands of at least two three species forming a multi-layered canopy with occasional srna11 openings; with at least 8 trees/acre (20 trees/hectare) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 inches (81 cm or more). NOTE: The criterion for dbh is based on measurements for upland forests. Two-hundred year old trees in wetlands will often have a smaller dbh because their growth rates are often slower. The DFW criterion is and "OR" so old-growth forests do not necessarily have to have trees of this diameter. __ Mature forests: (west of the Cascade Crest) Stands where the largest trees are 80 -200 years old OR have an average diameters (dbh) exceeding 21 inches (53 cm); crown cover may be less than I 00%; decay, decadence, numbers of snags, and quantity of large downed material is genera11y less than that found in old-growth. Cat. I YES -Category I NO - SCS Wetlands in Coastal Lagoons (seep. 92} Does the wetland meet a11 of the following criteria of a wetland in a coastal lagoon? __ The wetland lies in a depressional adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks gravel banks, shingle, or, less frequently, rocks __ The lagoon in which the wetland is located contains surface water that is saline or brackish (> 0.5 ppt) during most of the year in at least a portion of the lagoon (needs to be measured near the bottom.) YES -Go to SC 5.1 NO ___ not a wetland in a coastal lagoon SC 5.1 Does the wetland meet all of the following three conditions? __ The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing) and has less than 20% cover of invasive plant species (see list of invasive species on p. 74). __ At least 3/4 of the landward edge of the wetland has a I 00 ft. buffer of shrub, forest, or un-grazed or un-mowed grassland. Cat. I __ The wetland is larger than 1/10 acre (4350 square ft.) YES = Category I NO = Category II Cat. II SC6 lnterdunal Wetlands (seep. 94) Is the wetland west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? YES= Go to SC 6.1 NO ___ not an interdunal wetland for rating If you answer yes you will still need to rate the wetland based Oil its functions. In practical terms that means the following geographic areas: • Long Beach Peninsula --lands west of SR 103 • Grayland-Westport --lands west of SR 105 • Ocean Shores-Copalis -lands west of SR 115 and SR I 09 SC 6.1 Is the wetland one acre or larger, or is it in a mosaic of wetlands that is one acre or larger? YES -Category II NO -go to SC 6.2 Cat. II SC 6.2 Is the wetland between 0.1 and I acre, or is it in a mosaic of wetlands that is between 0.1 and l acre? YES -Category III Cat. III Category of wetland based on Special Characteristics ¢ Choose the "highest" rating if wetland/alls into several categories, and record on p. J. If you answered NO for all types enter "Not Applicable" on p. l Wetland Rating Fann-western Washington (11/04) Page 8 of8 I I I I I I I I I I I I I I I I I I I 7. OTHER PERMITS: A permit from Water District 90 and the City of Renton Sewer District is required for the water and sewer construction. I I I I I I I I I 'I I I 'I I I I I I I 8. CSWPPP ANALYSIS AND DESIGN: Design of the ESC plan was completed in conformance with Core Requirement #5 per the 2005 KCSWDM. Compliance with the 9 minimum requirements is summarized below. I. 2. 3. 4. 5. Clearing Limits: Clearing limits have been delineated on sheet C2.0l of the civil plans. The clearing limits extend only to those areas that will be disturbed during construction of the subject project. Cover Measures: The Erosion/Sedimentation Control Notes listed on sheet C2.3 l of the civil plans specify specific times at which temporary and permanent cover measures will be installed. Perimeter Protection: Per sheet C2.0l of the civil plans, silt fence will be used for perimeter protection. Silt fence will be installed along the perimeters of those areas that will be receiving silt-laden runoff. Traffic Area Stabilization: A construction entrance will be installed at the entrance to the project site. See sheets C2.01 and C2.3 l for location of construction entrance and detail. Sediment Retention: The proposed detention/water quality vault will be used for sediment retention. Sediment retention will be designed per the 2005 KCSWDM Appendix D. Surface Area: Q 10 (06083dev.tst) = 0.47 cfs (See attached KCRTS Flow Frequency Analysis in Section 4B of this Report) SA= 2080 sf/cfs * Q10 SA= 2080 sf/cfs * 0.4 7 cfs = 978 SF SA Provided= 2,584 SF> 978 SF => OK I I I I I I I I I I I I I I I I I I I Dewater Orifice: The dewatering orifice will be placed at the outlet to the vault. The sizing of the orifice is below: As (2h)05 Ao=----- 0.6x3600Tg05 Ao= 2,376 (2 x 3.5}5 294,166 Ao= 0.021 D = 24xj!i D = 24x ~ 0 -~ 21 D = 1.96" 6. Surface Water Collection: Interceptor swales will be used to direct all sediment- laden runoff to the sedimentation vault. See sheets C2.0l and C2.31 for location of swales and details. 7. Dewatering Control: A note on sheet C2.01 addresses the procedure for discharge/treatment of runoff from dewatering. 8. Dust Control: A note on sheet C2.01 addresses the procedure for dust control should soils become too dry. 9. Flow Control: The proposed detention/water quality facility will be used for sediment retention therefore, discharge from the facility will be per the Conservation (Level Two) Flow Control standard. Design of the SWPPS plan was completed in conformance with Section 2.3.1.4 in the 2005 KCSWDM. The ESC and SWPPS plan contains notes establishing what materials will not be allowed on the site along with notes describing BMPs for treatment of materials that will be on the site. Since no storage of liquids including fuel will be allowed on the site, no spill prevention report and/or clean up report is required. Vehicle maintenance will not be allowed on the site. Storage of construction materials and wastes will be stored within a designated stockpile area. Any concrete waste or waste from sawcutting or surfacing will be discharged to formed areas awaiting installation of concrete or asphalt and/or to a lined sump as specified in the notes and shown on the ESC and SWPPS plan. The contractor shall designate a person as the responsible representative in charge of erosion control and maintenance of all erosion control and stormwater pollution prevention facilities. I I I I I I I I I I I I I I I I I I I 9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT: A blank "Declaration of Covenant and Grant of Easement" along with maintenance and operation instructions for the "Perforated Pipe Connection" and "Permeable Pavement" are attached on the following pages. The blank "Declaration of Covenant and Grant of Easement" will be filled out and recorded during final plat. The "Facility Summary Sheet" and "Bond Quantities Worksheet" will be submitted upon approval of plans. I ''r--,-- I I I I I I tr I RECORDING REQUESTED BY AND WHEN RECORDED MAIL TO: RECORDING COVER SHEET DECLARATION OF COVENANT AND GRANT OF EASEMENT Grantor: -------------------- Grantee: -------------------- Legal Description:----------------------- I Additional Legal(s) on:---------------------- I I I I I I I'- I 11 Assessor's Tax Parcel ID#: --------------------- I I I I I I I I (( I le I I I I I I I B ,. _.; I 3. King County shall have a nonexclusive perpetual access easement on the Property in order to ingress and egress over the Property for the sole purposes of inspecting and monitoring the Property's Flow Control BMPs, and if applicable in accordance with the terms of Paragraph 4 below, performing any corrective work required to bring the Property's Flow Control BMPs into compliance with Title 9 of the King County Code. 4. If King County determines that maintenance, repair, restoration, and/or mitigation work is required to be done to the Flow Control BMPs and has not been performed by the Property owner(s), the Director of the Water and Land Resources Division of the King County Department ofNatural Resources and Parks shall give notice to the Property owner (s) of the specific maintenance, repair, restoration, and/or mitigation work (Work) required pursuant to Title 9 of the King County Code. The Manager shall also set a reasonable time in which the Work is to be completed by the Property owner(s). If the Work is not completed within the time set by the Division Director, King County may perform the required Work. Written notice will be sent to the Property owner(s) stating King County's intention to perform the Work. Performance of the Work by King County will not commence until at least seven (7) days after such notice is mailed. If, within the sole discretion of the Water and Land Resources Division Director, there exists an imminent or present danger, the owner hereby waives the seven (7) day notice period and the Work will begin immediately. 5. The owner(s) of the Property shall assume all responsibility for the cost of any Work required to be done to the Flow Control BMPs. Such responsibility shall include reimbursement to King County within thirty (30) days of the receipt of the invoice for any such Work performed by King County in accordance with the terms of Paragraph 3 above. Overdue payments will require payment of interest at the current legal rate as liquidated damages. In the event that King County does not receive reimbursement within the required time frame, it may elect to place a lien on the 3 I I I (( I I I I I I I ,,,--. \ I I I I I I I ,(,_) I IN WITNESS WHEREOF, this Declaration of Covenant and Grant of Easement is executed this ______ day of ____________ , 20_, Its -------------- Its -------------- STA TE OF WASHINGTON) )SS COUNTY OF KING ) On this day of , 20_, before me, the undersigned, a Notary Public in and for the State of , duly commissioned and sworn personally appeared , to me known to be the individual described in and who executed the foregoing instrument, and acknowledged to me that he signed and sealed the said instrument ash free and voluntary act and deed for the uses and purposes therein mentioned, WITNESS my hand and official seal hereto affixed the day and year in this certificate above written, Printed name Notary Public in and for the State of Washington, residing at _____________ _ My appointment expires ________ _ 5 ,, I, i I! I, 11 : I; I I I I I I I I I I I I I Property and act upon the lien in accordance with the terms and procedures specified in Chapter 23.40 of the King County Code, as amended from time to time. If legal action is taken to enforce the provisions of this Paragraph, the prevailing party is entitled to costs and attorney's fees. 6. Apart from performing routine landscape maintenance, the Property owner(s) is (are) hereby required to obtain written approval from the Water and Land Resources Division Manager of the King County Department of Natural Resources and Parks prior to performing any alterations or modifications to the Flow Control BMPs. Any notice or consent required to be given or otherwise provided for by the provisions of this Declaration of Covenant and Grant of Easement shall be effective upon personal delivefY, or three (3) days after mailing by Certified Mail, return receipt requested, whichever occurs sooner. 7. This Declaration of Covenant and Grant of Easement is intended to promote the efficient and effective management of surface water drainage on the Property, and it shall inure to the benefit of all the citizens of King County, its successors and assigns. This Declaration of Covenant and Grant of Easement shall run with the land and be binding upon Grantor(s), and Grantor's (s') successors in interest and assigns. 8. This Declaration of Covenant and Grant of Easement may be tem1inated by execution of a written agreement by Grantor(s) and King County expressing their mutual agreement to terminate this Declaration of Covenant and Grant of Easement. 4 I I I I I I I I I I I I I I I I I I I DECLARATION OF COVENANT AND GRANT OF EASEMENT For Stormwater Flow Control Best Management Practices IN CONSIDERATION of the following approved King County (check one of the following) D residential building permit, D commercial building permit, D clearing and grading permit, D subdivision pennit, or D short subdivision permit for Application No .. ________ _ relating to real property ("Property") legally described as follows: The Grantor(s), the owner(s) in fee of the above described parcel of land, hereby covenants with King County, a political subdivision of the state of Washington its successors in interest and assigns ("King County"), that it will observe, consent to, and abide by the conditions and obligations set forth and described in Paragraphs 1 and 2 and 4 through 7 below with regard to the Property, and hereby grants an access easement on and to the Property to King County, for the purposes described in Paragraph 3 below. Grantor(s) hereby grants, covenants, and agrees as follows: 1. Owner(s) of the Property shall retain, uphold, and protect the stormwater management devices, features, pathways, limits, and restrictions, known as flow control best management practices ("Flow Control BMPs"), shown on the approved Flow Control BMP Site Plan for the Property attached hereto and incorporated herein as Exhibit A. 2. Owner(s) of the Property shall iit their own cost, operate, maintain, and keep in good repair, the Property's Flow Control BMPs as described in the approved Design and Maintenance Details for each BMP attached hereto and incorporated herein as Exhibit B. 2 I I I I I I I I I I I I I I I I I I I MAINTENANCE AND OPERATION INSTRUCTIONS FOR PERFORATED PIPE CONNECTION Your property contains a stormwater management flow control BMP (best management practice) called a "perforated pipe connection," which was installed to reduce the stormwater runoff impacts of some or all of the impervious surface on your property. A perforated pipe connection is a length of drainage conveyance pipe with holes in the bottom, designed to "leak" runoff, conveyed to the pipe, into a gravel filled trench where it can be soaked into the surrounding soil. The connection is intended to provide opportunity for infiltration of any runoff that is being conveyed from an impervious surface (usually a roof) to a local drainage system such as a ditch or roadway pipe system. The size and composition of the perforated pipe connection as depicted by the flow control BMP site plan and design details must be maintained and may not be changed without written approval either from the King County Water and Land Resources Division or through a future development permit from King County. The soil overtop of the perforated portion of the system must not be compacted or covered with impervious materials. I I I I I I I I I I I I I I I I I I I MAINTENANCE AND OPERATION INSTRUCTIONS FOR PERMEABLE PAVEMENT Your property contains a stormwater management flow control BMP (best management practice) called "permeable pavement," which was installed to minimize the stormwater quantity and quality impacts of some or all of the paved surfaces on your property. Permeable pavements reduce the amount of rainfall that becomes runoff by allowing water to seep through the pavement into a free-draining gravel or sand bed, where it can be infiltrated into the ground. The type of permeable pavement used on your property is permeable pavers. The area covered by permeable pavement as depicted by the flow control BMP site plan and design details must be maintained as permeable pavement and may not be changed without written approval either from the King County Water and Land Resources Division or through a future development permit from King County. Permeable pavements must be inspected after one major storm each year to make sure it is working properly. Prolonged ponding or standing water on the pavement surface is a sign that the system is defective and may need to be replaced. If this occurs, contact the pavement installer or the King County Water and Land Resources Division for further instructions. A typical permeable pavement system has a life expectancy of approximately 25-years. To help extend the useful life of the system, the surface of the permeable pavement should be kept clean and free of leaves, debris, and sediment through regular sweeping or vacuum sweeping. The owner is responsible for the repair of all ruts, deformation, and/or broken paving units. I I I I I I I I I I I I I I I I I I I 10. OPERATIONS AND MAINTENANCE MANUAL: A maintenance and operations manual is not required since all drainage facilities will be public. Web date· 06/29/2007 ti King County Department of Development and Environmental Services 900 Oakesdale Avenue Southwest Renton, Washington 98057-5212 206-296-6600 TIY 206-296-7217 DROP-OFF COVER SHEET FOR LUSD ONLY For alternate formats, call 206-296-6600. Drop-Off Cover Sheet for Land Use Services Division oooooeoooooo•eooo IMPORTANT oooeoeoeooeeooooo DATE RECEIVED BY LUSD PROJECT NUMBER AND NAME IS NECESSARY fOR ALL DROP-OFFS Project No L-D i S f:. 01J) Project Name PJJ.e.ao~ f pf1v FROM ifo~ ~I U){Z0 [)?5fg~ Corf any N~me / Contact Person 1 Telephone No j '2,. 5 ~ ?~.S::-7 g I TO [?de~ ADDITIONAL INFORMATION REQUESTED BY KING COUNTY STAFF (please print) Short Plat/ Plats Please specify item(s) dropped-off: Lot Line Adjustment Permit Please specify item(s) dropped-off: Right of Way Permit Please specify item(s) dropped-off: Clearing / Grading Permit -Additional information requested. Please specify item(s) dropped-off: Other: ~ n ~ e rr, (I> "" = = = :z,,. .:, ::0 "' Q) ,, :ir ~ .&:- \D :::;,;; i\'1 f) rr1 "CC rrt 0 PLEASE NOTE: All drop-off item(s) will be logged into the computer under the project number, therefore, it is important that the top portion of this form is completed properly before you drop-off anything. Assistance in finding a project number can be provided by speaking to a Zoning/Land Use Technician. Your cooperation is important. Thank you. Check out the DDES Web site at www.kingcounty.gov/permits Drop-OffCoverSheet-LUSDOnlyFORM.doc lg-cvs-dropoff.pdf 06/29/2007 Page 1 of 1 ~ <f:0!2.IE ~DESIGN ENGINEERING PLANNING SURVEYING DATE: 4-28-08 TO: King County DDES ATTN: Pete Dye CORE PROJECT NO: REFERENCE: FROM: SENDING VIA: (ore De•lgn, Inc. 14711 N.E. 29th Place, Suite 101 Bellevue, Washington 98007 425.885.7877 Fax 425.885.7963 www.coredesigninc.com 06083 Pleasant Path L08SR020 Robert Stevens, P.E. ADDRESS: 900 Oakesdale Ave SW Renton, WA 98055 0 MAIL O PICK-UP [8] HAND DELIVER 0 COURIER 01-HR O 2-HR 04-HR 0 OVERNIGHT QUANTITY DATED DESCRIPTION 3 Tech. Information Report (TIR) 3 Road, Grade and Storm Drawings 1 Sewer Drawing 1 Water Drawing 1 Check $765 1 Cert. of Applicant Status TRANSMITTED: [8] FOR YOUR USE [8] PER YOUR REQUEST ACTION REQUIRED: 0 PROCESSING 0 REPLY 0 RETURN 0 INFORMATION ONLY [8] NONE COMMENTS: For your review. Thank you. CC: Robert Johnseine BY: mJrn@rnowrn@ APR 28 7008 K.C. D.D.E.S. ( ~obert Ste,eos, P.E r OK [ l [ l [ l [ l [ l [ l [ l [ l [ l Activity Number:_------- GENERAL SUBDIVISION REQUIREMENTS Site plan layout matches preliminary plat approved by Hearing Examiner (Check for same lot count, tract configuration, road alignments, etc ... ) Compliance with conditions of preliminary approval Compliance with Mitigated Determination of Non-Significance Tract Table if three or more tracts. Identify name, size and purpose. Show and label all SAO tracts, buffers, and IS' BSBL. Review maximum height of 6-feet for rockeries and retaining walls per KCC 21 A.12.030, 110-170, 220) Also show standard note per policy on web site. Use updated cover sheet showing designation for _highly sensitive sites per Appendix, D73. Determine if HP A fisheries permit required-contact CAO staff. Tree Retention Plans -Show standard plan note (see section policies). SURFACE WATER DESIGN MANUAL (2005) CORE AND SPECIAL REQUIREMENTS SWDM [ ] 1.2.1 Core# I -Evaluate diversion of drainage within subbasins, discharge of unconcentrated runoff, and/or tightline requirements for landslide hazard drainage areas. [ ] 1.2.2 Core #2 -Offsite'analysis. Evaluate adequacy and conclusions. [ ] 1.2.3 Core #3 -Flow control. Determine design standard based upon mapping and/or offsite analysis. Evaluate exemptions from flow control if applicable. Also evaluate target surfaces and BM P criteria. [ ] 1.2.6 Core #6 -All drainage facilties and road access shall be located in public tracts, right-of- way and/or drainage easements dedicated to King County. For private facilities, specify the required Declaration of Covenant and drainage easements for final recording. [ ] 1.2.8 Core #8 -Water Quality. Determine design standard based upon mapping and/or offsite analysis. Evaluate need for enhanced basic water quality based upon five land use types, including subdivision density=> 8 units per acre developed area. Also evaluate exemptions if applicable and untreated discharge per page 1-67. [ ] 1.3. I Special # I -Area specific requirements. Perform P-suffix search on computer, evaluate grading code restrictions, critical drainage areas, and review for shared facility drainage plan. [ ] 1.3.2 Special #2 -Floodplain boundaries and channel migration areas shown on plans. DRAINAGE ADJUSTMENTS [ l 1.4 Activity No. ______ _ Approval Date: _____ _ Design Issues PLANS REQUIRED FOR DRAINAGE REVIEW [ l [ l [ l [ l 2.1.2 Updated 04/07 Site Improvement Plans ESC Plan Storm water pollution plan (SWPPS) Technical Information Report (TIR) Page 2 of 15 ; · t{J King County Department of Development and Environmental Services 900 Oakesdale Avenue Southwest Renton, WA 98057-5212 206-296-6600 TTY 206-296-7217 www.metrokc.gov PROJECT INFORMATION Project Name: Johnseine Robert Activity Number: L08SR020 Project Number: L07S0018 Development Number: _______ _ DDES Review Engineer: __________ _ Notes: Date: ---- [ l [ l [ l [ l [ l Hearing Examiner's Report .... Date: ____ Revised Report ..... Date: __ _ Plat Ordinance Number: _____ Date: _____ _ Preliminary Plat Map ......... Date Approved by Hearing Examiner: ___ _ Revised Preliminary Plat Map ......... Date Approved by ODES: ____ _ 5-year Expiration .......... Date: (Show on engineering cover sheet) ROUTING TO OTHER KING COUNTY SECTIONS [ l Wetland Report/Plans: Route Date: ___ _ Response date: ----- [ l Geotechnical Report/Plans: Route Date: ___ _ Response date: ____ _ [ l Grading Report/Plans: Route Date: ___ _ Response date: ____ _ [ ] Structural Designs/Calculations/Civil Plans/Soils Report (Vaults, Retaining Walls, Bridges) Route Date: Response date: ----- [ l Landscape/Recreation/Street Tree/Plan: Route Date: ___ _ Response date: ____ _ [ l Traffic Improvement Plan/Report: Route Date: ___ _ Response date: ____ _ [ l Tree Retention/Forestry/Plan: Route Date: ___ _ Response date: ----- [ l Other Report/Plan Route Date: ___ _ Response date: ____ _ [ l Site Inspections -Constructability Route Date: ___ _ Response date: ____ _ [ ] All required routing stations shown and updated on PRMS Updated 04/07 Activity Number:. _______ _ TECHNICAL INFORMATION REPORT OK [ l [ l [ l [ l [ l I l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l SWDM 2.3.1.1 Section 1 -Project Overview Figure 1: TIR Worksheet Figure 2: Site Location Figure 3: Drainage Basins a. Acreage of subbasins. b. Identify all site characteristics c. Show existing discharge points to and from the site d. Show routes of existing, construction, and future flows at all discharge points and downstream hydraulic structures. e. Use a minimum USGS 1 :2400 topographic map as a base f. Show and cite the length of travel from the farthest upstream end of a proposed storm system in the development to any proposed flow control facility. Figure 4: Soils a. Show the project site. b. the area draining to the site. c. the drainage system downstream for the distance of the downstream analysis. Section 2 -Preliminary Conditions Summary with responses Section 3 -Off-Site Analysis Section 4 -Flow Control and Water Quality Facility Analysis and Design Existing Site Hydrology (Part A)-Topographical map with listed site information. Developed Site Hydrology (Part B) -Data/narrative for developed site conditions. Performance Standards (Part C)-Summarize flow control and BMP's. Flow Control System (Part D) -Illustrative sketch and documentation. Water Quality System (Part E) -Illustrative sketch and documentation. Section 5 -Conveyance System Design and Analysis Section 6 -Special Reports and Studies -Geo, Wetlands, Flood analysis (4.4.2), etc. Section 7 -Other Permits ( HPA, Special Use, WSDOT, etc .... ) Section 8 -Design Requirements for Erosion/Sedimentation Control and Storm water Pollution (SWPPS) Section 9. -Bond Quantities Worksheet, RID Facility Summary, Private Covenants Section 10 -Maintenance and Operations Manual (Section 10 for privately maintained or special non-standard features) SITE IMPROVEMENT PLANS OK [ l [ l [ l SWDM 2.3.1.2 Vertical Datum NAVD 1988-show benchmark Horizontal Control NAD 1983/91 Base Map per table 2.3.1.A 2.3.1.2 General Plan Format [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l Updated 04/07 (1) Sheet size 24" X 36"; quality reproducible (2) King Co. Standard Map Symbols; existing/proposed (Reference 7A) (3) Project Information/Cover Sheet a. Title: Project name and DDES file number b. Table of Contents if more than 3 plan sheets c. Vicinity Map d. Name & Phone of Utility field contacts and One Call Number: 1-800-424-5555 (water, sewer, gas, power ... ) e. Preconstruction/lnspection notification requirements f. Name and Phone of erosion control supervisor g. Name & Phone of Surveyor Page 3 of 15 OK [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l SWDM 2.3.1.2 Activ1ry Number: _______ _ SITE IMPROVEMENT PLANS (cont.} h. Name & Phone of Owner/Agent i. Name & Phone of Applicant j. Legal description k. Plan approval block for ODES I. Name & Phone of engineering firm preparing plans m. Fire Marshal's approval stamp (if required) n. Mailbox location approval by U.S. Postal Service o. List of conditions of preliminary approval on all site improvements (4) An overall site plan if more than three plan sheets are used. a. The complete property area development b. Right-of-way information c. Street names and road classification d. All project phasing and proposed division boundaries e. All natural and proposed drainage collection and conveyance systems with catch basin numbers shown (5) Each sheet and TIR is stamped, signed, and dated by a Professional Engineer licensed in Washington State. Survey control plan sheet stamped by licensed PLS in Washington State (6) Detail Sheets Provided (7) Title block on each sheet a. Development title b. Name, address and phone number of engineering firm c. Revision block d. Page numbering e. Sheet title (e.g., road and drainage, grading, etc.) (8) King County approval block on each plan sheet. (9) The location and label for each section or other detail shall be provided. ( 10) Critical Areas with buffers and setbacks. ( 11) All match lines correspond to the sheet referenced ( 12) Division phase lines with limits of construction (13) Wetlands with inventory numbers (14) Standard Plan Notes -General, Drainage, & Structural notes (Reference 7B) Plan View: Site Plan and Roadway Elements ( 1) Property I ines, R/W I ines, roadway widths shown (2) Existing/Proposed ·road features; CL, edge pavement, edge shoulder, ditches, curb, sidewalk, & access pts (3) Existing/Proposed Topographic Contours@ 2', 5'> 15% slope, 10'>40% slope (4) All affected utilities are shown; utility poles marked (5) All roads and adjoining subdivisions identified (6) Existing/Proposed R/W dimensioned and shown (7) Existing/Proposed surfacing shown (8) Scale generally 1 "=50' ( 1 "= 1 00' for lots > I Acre) 2.3.1.2 Plan View: Drainage Conveyance [ l [ l [ l [ l [ l [ l Updated 04/07 Sequentially number all catch basins and curb inlets Show length, diameter, and material for all pipes, culverts, and stubouts Label catch basin size and type Show stub out locations for roof drains Label all drainage easements, access easements, tracts, and building setbacks Provide flow arrows for drainage direction. Page 4 of 15 Activity Number: _______ _ SITE IMPROVEMENT PLANS (cont.) [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l Notes:· SWDM 2.3.1.2 Plan View: Other Show all buildings, property lines, streets, alleys, and easements. Verify condition of public right-of-way. Show structures on abutting properties within 50 feet Identify fencing for drainage facilities Provide section details of all retaining walls and rockeries Show all wells on site and within l 00-feet of site. For well abandonment, include notes referencing DOE procedures. Show flow control BMP's and source control BMP's for SWPPS. 2.3.1.2 Profiles: Roadway and Drainage Existing/Proposed roadway centerline (CL) at 50' stations increasing, reading from left to right. Show stationing of points of smooth vertical curve, with elevations Show vertical curve data including stopping sight distance Show all pipes and detention tanks with slope, length, size, type Show all pipe inverts and elevations of catch basins or lids Minimum cover dimensions if less than 2.0' Indicate roadway stationing and offset for all catch basins. Show vertical and horizontal scales (vertical l"; 5') Label all profiles with street names and reference numbers to plan sheet. Show all property boundaries and match line locations. Provide profiles for conveyance systems of 12" and larger pipes or channels other than roadway ditches Catch basin lids are flush with ground line 2.3.1.2 Plan Details Provide scale drawing of each pond, vault, or water quality facility. Include all pipe details for size, type, slope, length, etc. Show existing and final grade contours at 2-foot intervals. Show maximum design water elevation. Dimension all berm widths. Provide two cross sections through pond, including one section through restrictor. Specify soils and compaction requirements Show location and detail of emergency overflows, spillways, and bypasses. Specify rock protection/energy dissipation details Provide inverts for all pipes, grates, etc. and spot elevations on pond bottom. Show location of access roads to control manholes and pond/fore bay bottoms. Provide plan and section views of all energy dissipaters. Specify size and thickness of rock. Show bollard locations (Typically at entrance to drainage facility and walking trails). Restrictor and control structures must have section and plan view drawn to scale. 2.3.1.2 Structural Plan Details Verify that designer is a licensed structural P.E. for vaults or bridges. Page 5 of 15 Updated 04/07 Activity Number: _______ _ EROSION AND SEDIMENT CONTROL (SWDM Appendix D) SWDM 2.3.1.3 General Specifications [ ] Separate plan sheet showing entire site w/features. [ ) Show sensitive areas and buffers in separate tracts. [ ) Show existing contours and final grades if scope of work includes grading. [ ] Pertinent information from soils report is added to plans. [ ] Drainage features identified (streams, wetlands, bogs, springs, seeps, swales, ditches, pipes, & depressions). [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l 2.3.1.4 D.3.1 D.3.2 D.3.3 D3.4 Utility corridors other than roads shown. Show drainage divides and flow directions. Specify best management practices. Show cut and fill slopes with catch lines indicated. Sufficient conceptual details to convey design intent. Standard ESC plan notes shown on plans (Page D-92). For grading and structural fill within lot areas -show standard notes for geotechnical work. (See section policies for geo notes) Storm Water Pollution Prevention and Spill Plan (SWPPS) A. Activity Specific Infonnation B. SWPPS Site Plan C. Pollution Prevention Report D. Spill Prevention and Cleanup Report Clearing Limits (1) Delineate clearing limits -colored survey tape may be used. Sensitive areas require plastic/metal safety fence or stake and wire fences. (2) Provide detail of fencing Cover Measures (I) Specify the type and location of temporary and pennanent cover measures. Mulch, erosion control nets, blankets, plastic, seeding and sodding. (2) Specify the seed mixes, fertilizers, and soil amendments to be used and applications rates. (3) Areas receiving special treatment are specified Uute netting, rock lining, or sod). (4) Soil cover practices and locations of disturbed areas. Perimeter Protection (I) Specify the location and type of perimeter protection to be used-silt fence, brush barriers, and/or vegetated strips. (2) Provide details and specify type of fabric for silt fence. Traffic Arca Stabilization (I) Show construction entrance with detail (Fig. D.3.4.A). (2) Show proposed construction roads and parking areas. Specify details for stabilization. D.3.5 Sediment Retention [ l [ l [ l [ l Updated 04/07 ( 1) Show location of sediment pond or sediment trap. Very small areas can be treated with only perimeter protection (See 0.3 .3). (2) Sediment Trap -Can be used for drainage areas 3 acres or less. Calculate surface area using 2-year design storm. Show detail per Figure D.3.5.A. (3) Sediment Pond-Determine pond geometry and show details on plan for required storage, depth, length, and width. (4) Show sediment pond cross section and detail (Figures 0.3.5.B,C,D) Page 6 of 15 Act1v1ty Number:, _______ _ EROSION AND SEDIMENT CONTROL /SWDM Appendix D} /cont.) OK [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l SWDM (5) (6) (7) (8) Provide details of cell dividers and stabilization techniques for inlet/outlet. Specify mulch or recommended cover of berms & slopes. Specify the I-foot marker for sediment removal. Indicate catch basins for protection and show design details (Fig. D.3.5.E,F,G,H). D.3.6 Surface Water Collection (I) Show conveyance of all surface water to a sediment pond or trap. (2) Discharge location shall be downslope from disturbed areas. (3) Show details for conveyance with interceptor dike, swales. (Figures D.3.6.B,C). ( 4) For ditches, determine capacity for 10-year storm with 0.5 feet free board. Show details for check dams (Fig. D.3.6.E). Determine check dam spacing and as needed, show inverts and minimum slopes ofopen channels. Also show direction of open channel flow. (5) For pipe slope drains, determine capacity for JO-year storm. Show details per Fig. D.3.6.D. (6) Determine level of protection for outlet (rock pad, outfall design, or level spreader). See requirements in D-63 through D-64. (7) Evaluate offsite flows entering the site and assure bypass of disturbed areas. D.5.1 ESC Plan (]) Show detailed construction sequence (page D-93). (2) All required calculations and soils reports contained in TIR. (3) For large projects, determine need for phased clearing. D.5.2 Wet Season Requirements [ ] ( 1) Provide a list of all applicable wet season requirements. (Details on page D-72) D.5.3 Critical Area Restrictions [ ] ( 1) Consider phased construction during the dry season. See special recommendations on page D-72/73. D.5.4 Maintenance Requirements [ ] (]) Plans shall list the name, address and phone number of the ESC Supervisor. A sign, [ l [ l shall also be posted on the construction site with information for contacting the ESC supervisor. See KCC 20.20.060(1) and web site policy for sign details. (2) Determine if site is Highly Sensitive (Soil Types C or D, 5 acres of disturbance, large areas with slopes > 10%, proximity to streams, wetlands, or lakes). (3) On cover sheet of engineering plans, designate if highly sensitive site. D.5.6 NPDES Requirements [ J (!) Determine if project will disturb more than 1 acre. [ ] (2) If disturbed area is greater than 1 acre, show the following note on the plans: "No construction or site disturbance for this project may begin before the applicant first obtains a General Permit to Discharge Stormwater Associated with Construction Activity permit from the Washington State Department of Ecology (DOE). For more information or application form, please visit DOE's web site at http://www.ecy.wa.gov/pubs/9937.pdf D.5.7 Forest Practices Permit [ J (1) Determine if project needs FPA permit. Contact DOES grading section. [ J (2) Provide a reference note on the cover sheet indicating whether or not a FPA permit has been obtained. Page 7 of 15 Updated 04/07 Activity Number: _______ _ EROSION AND SEDIMENT CONTROL (SWDM Appendix D) (cont.) OK SWDM Early Start Plan Review [ J (1) Standard Cover sheet included with Title for Phased Early Start. [ ] (2) List the scope of work for early start (Scope of work will vary for each project - Evaluate clearing, grading for roads, lot grading, utility installation, vault construction, offsite work) [ l [ l [ l [ l [ l [ l (3) Update the sheet index to identify all plans with updated page numbers. (4) Include standard ESC plan prepared in accordance with all requirements listed above for erosion and sediment control. (5) Include pollution control plan elements as required by SWDM( pg 2-16, 2-28) (6) Include detailed construction sequence and identify ESC supervisor. (7) Show standard erosion control notes. (8) Show early start activity number on all plan sheets. DESIGN REQUIREMENTS [ l [ l [ l 3.2 Runoff Computation Rational Method required for onsite conveyance (See Table 3.2) KCRTS used for flow control design Evaluate correct data: Rainfall region, scale factor, time step, record type, acreages, soil cover groups, and percent impervious. (See correct time steps -page 3-23) [ ] 1-29 For Conservation Flow Control, apply historic site condition for predevelopment [ ] 3-27 For urban areas, unprotected forest modeled as pasture or grass [ ] For rural areas, unprotected forest assumes 50% grass, 50% pasture [ ] All pre developed grassland modeled as pasture [ ] All post developed grassland modeled as grass [ ] Impervious coverage calculated based upon specific project -clearly summarize types and amounts of impervious. [ l [ l For urban development, impervious for each lot,>= 4,000 sq ft or maximum allowed in zoning code. For rural development, impervious for each lot,>= 8,000 sq ft or maximum allowed in zoning code. [ ] Evaluate requirements for modeling with effective impervious area. [ ] 3.3.6 Point of compliance -evaluate for on site bypass and off site closed depression. [ J 3.3.7 Onsite closed depressions and ponding areas. [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l 4.0 Conveyance System Analysis and Design Conveyance systems are in easements of correct width with BSBL's . Off site easements must be recorded using standard forms (Reference SL) Determine which easements are public and private, label and dimension. Pipes are parallel to and alongside property lines 4-7 Minimum pipe size 12-inch. Private systems may allow 8 inch. Show easements for pipes extending outside right of way. 4-9/10 For connecting pipes at structures, match crowns, 80% diameter, or inverts For connections to manholes, pipes 12 "and smaller do not need to match crowns or inverts. 4-11 Minimum velocity at full flow 3.0 feet per second. 4-11 Minimum cover for pipes 2 feet. 4-13 Debris barrier for pipes 18-36 inch 4-29 Outfall design criteria Surcharges (backwater analysis may be required) 4-38 Trash Racks 4-37 Maximum headwater allowed for culverts 4-53 Bridge design 4-55 Open channels 4-71 Floodplain analysis Page 8 of 15 _Updated 04/07 Activity Number: _______ _ DESGN REQUIREMENTS (cont) SWDM 5.2 [ l [ l 5-6 [ l 5-7 [ l 5-8 [ l Flow Control BMP Requirements Determine if project proposes BMP's as flow control credits. If credits not proposed, skip to (A) below. Small Lot BMP's -Demonstrate feasibility of full dispersion and/or full infiltration. If not feasible, choose other BMP's as listed. Large Lot Low Impervious BMP's -Demonstrate feasibility offull dispersion and/or full infiltration. If not feasible, choose other BMP's as listed. Large Lot High Impervious BM P's -Demonstrate feasibility of full dispersion . If full dispersion not feasible, choose other BMPS's as listed. For any BMP chosen, designate which lots are proposed for BMP's and show appropriate design details from Appendix C. [ ] 5-12 Evaluate facility sizing credits for flow control BMP's. [ ) 5-13 Evaluate BMP's within road right-of-way. [ ] 5-13 Evaluate BMP's within dedicated tracts. [ ] 5-14 Evaluate BMP implementation requirements on individual lots and perform lot-specific [ l [ l [ l Updated 04/07 assessment to determine feasibility. Determine which of the following four scenarios apply for site development: (A) Flow control credits are not used and all BMP issues are deferred to the building permit review process. In this case, the engineering plans shall show roof drain connections for all lots and the following note must be shown on the design plans: "The following note shall be shown on the final recorded plat: "Permit applications for buildings or other improvements constructed on lots created by this subdivision must be reviewed by King County for compliance with best management practices (BM P's) and other applicable drainage standards as specified in the King County Surface Water Design Manual. As determined necessary by King County, the permit applicant for each lot must prepare a drainage site plan with procedures for design and maintenance details, and record a declaration of covenant and grant of easement for implementaiion of the best management practices." (B) Flow control credits are used for sizing the drainage facility and the plat developer will implement the required BM P's as part of the subdivision process. This will occur only for certain types of BMP's such as full dispersion to an open space tract, full infiltration for entire plat, or construction of a joint use rain garden located within a separate tract. The feasibility ofBMP's has been determined with design details shown on the plans including roof drain connections. In this case, the final plat must record a note indicating that BMP requirements are satisfied and building permit review is not required. Additional notes are needed to specify tract ownership and maintenance requirements for BMP facilities and the standard declaration of covenant easement shown in the drainage manual (Reference 8M) shall be recorded as necessary. Show the following notes on the engineering plan: I) The following note shall be shown on the final recorded plat: "Single family residences and other improvements constructed on lots created by this subdivision shall connect roof downspouts and drains from other impervious surfaces to the permanent storm drain outlet shown on the approved construction drawings for this subdivision. All storm drain connections must be constructed and approved prior to final building inspection approval. The designs for best management practices (BMP's) as required by the King County drainage manual have been satisfied during development of the subdivision and no further drainage review is required for individual building permits." 2) The Declaration of Covenant and Grant of Easement shown in Reference Section 8M of the King County drainage manual shall apply to Tracts and be recorded with the final plat. Page 9 of 15 Activity Number: _______ _ DESIGN REQUIREMENTS (cont) SWDM (C) Flow control credits are used for sizing the drainage facility and the plat developer · chooses to defer implementation ofBMP's to the building permit process. This process would apply for certain types of BMP's such as lot infiltration, limited infiltration, basic dispersion, individual lot rain gardens, permeable pavement, reduced impervious surface within lots areas, etc ... The subdivision review will demonstrate the feasibility of certain types ofBMP's for all or some lots and design details are shown on the plans. In this case, the recorded plat would contain a note requiring future review of building pe~its as shown on page 5-14 in the drainage manual. At the time of plat recording, the declaration of covenant and grant of easement must also be recorded for specified lots. The following notes shall be shown on the engineering plans: I) The Declaration of Covenant and Grant of Easement shown in Reference Section 8M of the King County drainage manual shall apply to lots __ and be recorded with the final plat. 2) The following note shall be shown on the final recorded plat: "Single family residences and other improvements constructed on lots (lots numbered_,_, ) created by this subdivision must implement the flow control best management practices (BMP's) stipulated in the drainage plan declaration of covenant and grant of easement recorded for each lot. Compliance with the stipulation must be addressed in the small project drainage plan submitted for drainage review when application is made for a single family residential building pennit for the lot." (D) Flow control facilities may not be required for certain types of subdivisions which meet the flow control exemption criteria; however, the building permits must still comply with BMP requirements in the drainage manual. In this case, the recorded subdivision must contain notes indicating the need for drainage review of each building pennit. Show the following note on the engineering plans: "The following note shall be shown on the final recorded plat: "Single family residences· and other improvements constructed on lots created by this subdivision must be reviewed by King County for compliance with best management practices (BMP's) and other applicable drainage standards as required by the King County Surface Water Design Manual."" ( ] 5-14 Demonstrate compliance with details for declaration of covenant and grant of easement including site plans and maintenance details. For either of options B or C shown above, the following note shall also be shown on the engineering plans: " The final plat shall record the required maintenance responsibilities and declaration of covenant and grant of easement as described in the drainage manual on page 5-9 for each lot within the subdivision required to implement drainage BMP's. [ l [ l [ l [ l [ l 5.3 For any connection of roof downspouts to the local drainage system, use perforated pipe connection per Appendix C, page C-77. Use of credits by projects within rights-of-way. Detention Facilities Emergency overflow -Evaluate flow path for safe and adequate conveyance Setbacks Flow-through system [ ] 5.3.1 Detention Ponds [ ] Dam Safety Compliance [ ] Two cross-sections through pond (one x-section to include control structure) [ ] Review pond details in Figures 5.3.1.A and B. [ ] Designed as flow-through system [ ] Side slopes interior 3H: 1 V or fenced Page 10 of 15 Updated 04/07 Activity Number: _______ _ DESIGN REQUIREMENTS {cont) OK [ l [ J [ J [ l [ J [ J [ J [ J [ J [ l [ l [ J [ J [ l [ J [ l [ J [ l [ l [ J SWDM Vertical interior retaining walls Stamped by licensed structural civil engineer. For pond walls, min. 25% of perimeter vegetated and no steeper than 3: I. Minimum top width of berm 6 feet. Berms greater than 4 feet require key excavation. Primary overflow (control structure with riser). Secondary Inlet to the control structure. Emergency Overflow Spillway, I 00 year de~eloped peak flow Soil and compaction requirements described (95% modified proctor) Access road min. turning radius, maximum grade, min. width, fences or gates. Pond sign (Figure 5.3.1.D) 2Fencing and planting requirements. Setbacks -5 feet from tow of exterior slope or 5 feet from water surface for cut slope 5.3.2 Detention Tanks Flow-through system required 6" of dead storage in tank bottom. Minimum pipe diameter of36". Materials and structural stability. Control structure per Section 5 .3 .4 Buoyancy Access risers and CBs are spaced properly with max. depth from finished grade to tank invert shall be 20 feet and accessible by maintenance vehicles. Hanging sign required for OSHA confined space requirements. [ J 5.3.3 Detention Vaults [ ) Structural package submitted for approval [ ) Flow-through system required [ ) Review design details per Fig. 5.3.3.A, Note: grate over sump with 2' x 2' hinged access door. (2x2 access door also required for 5x IO grate ifover inlet or outlet). [ l Access positioned a maximum of 50 feet from any location. (if over 3 foot cover use cone riser). Access required to inlet pipe and outlet [ l [ l [ l [ l [ l [ l [ l For vault under roadway, removable panel located outside travel lanes. Hanging sign required for OSHA confined space requirements. Removable 5xl O panel if vault greater than 1250 sq. ft. floor area. Maximum depth from finished grade to vault invert to be 20 feet. Minimum internal height shall be 7 feet, min. width shall be 4 feet min. Ventilation pipes provided in all four corners. [ ) 5.3.4 Control Structures [ ) Section and plan view shown to scale [ J Orifice size and elevation on plans match calculations. Minimum orifice 0.5'' [ J (Note: Information Plate details are no longer required -See policy on web site). [ ) 5.4 Infiltration Facilities [ ) Appropriate soils logs and testing procedures in TIR. [ J Pond bottom at least 3 feet above seasonal high water [ ) Permeable soil extends minimum 3 feet below bottom of pond. [ J Geotechnical report states suitability and determines design infiltration rate. [ J Overflow route identified with I 00-yr overflow conveyance. [ J Spill Control device upstream of facility. [ ) Presettling [ J Review setback requirements, page 5-60. Design water surface setback of20 feet from external tract, easement or property lines. [ l Show standard note regarding public rule for in operation facility (see section policies) Page 11 of 15 Updated 04/07 Activity Number: ______ _ DESIGN REQUIREMENTS (cont.) [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ J [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l SWDM 6.0 Water Quality Design 6.1 Water Quality Menus 6.2. Water Quality facilities 6.2.2A Water Quality Sequencing 6.2.3 Setbacks, slopes and embankments 6.2.4 Facility Liners 6.2.5 Flow Splitter Designs 6.3 Biofiltration Facility 6.3.1 Biofiltration swales and soil amendments 6.3.1.1 Methods of Analysis 6.3.1 Swale geometry, plantings, flow conveyance, high flows, velocity. Road access requirements, page 6-43. 6.3.4 Filter strip geometry (slopes) 6.4 Wetpool Facility Designs Wetpool geometry, 2 cells, minimum depth of first cell 4 feet. Flowpath length to width ratio 3: I, without internal berms or walls. 6.4.1.2 Berms, Baffles, Slopes Inlet/Outlet Design 6.4.1.1 Access, setbacks, and plantings 6.4.2 Wetvaults 6.4.1.1 Sizing basic or large 6.4.1.1 Berms, Baffles, Slopes 6.4.2.2 Two cells separated by wall or removable baffle. Vault bottom forms a broad "V" with 5% sideslopes. Inlet is submerged and outlet pipe designed for I 00-year overflow. Gravity drain provided if grade allows Minimum 50 square feet of grate over second cell. 5-foot minimum wet pool depth based on inlet design criteria. 6.4.3 Stormwater Wetlands 6.4.3.1 Methods of Analysis 6.4.3.2 Design Criteria -Wetland geometry, liners, access, plantings 6.4.4 Combination Detention and Wetpool facilities 6.4.4.1 Methods of Analysis 6.4.4.2 Design Criteria -Detention and wetpool geometry, benns, baffles, slopes 6.4.4.2 Access and plantings 6.5 Media Filtration Facility Designs 6.5.1 Pre-settling/Pre-trea,tment 6.5.2 Sandfilters -Basic and Large 6.5.2.1 Methods of analysis 6.5.2.2 Design Criteria -Geometry, overflow/bypass, underdrain, and access 6.5.3 Sandfilter Vaults 6.5.3.2 Design Criteria -geometry, pretreatment, flow-spreading, energy dissipation, 6.5.3.2 Overflow/bypass, underdrain and access NOTES: Page 12of15 Updated 04/07 OK [ l [ l [ l [ l Code 16.82. JOO 16.82.150 16.82.152 16.82.156 Activity Number:. ______ _ CLEARING AND GRADING CODE KCC 16.82 Soil Amendments-Sections F and G. Note: For subdivision review, apply soil amendments to disturbed areas outside lots. Building permits will be reviewed separately. Clearing standards for individual lots in rural zones. Clearing standards for subdivisions in rural residential zone. Significant trees within the urban growth area NOTES: KING COUNTY ROAD STANDARDS (1993) 1993 DESIGN REQUIREMENTS [ ] 1.0 General Considerations [ ] 1.03 A, B Offsite and frontage improvements determined by reviewing agency. Note: For grading permits, the required extent of road improvements must be determined during engineering review. For subdivisions, the requirements are detennined during preliminary review. [ ] 1.03 D Subdivisions must have recorded public access except for private roads. [ ] 1.08 Variances: [ l [ l [ l [ l [ l [ l [ l [ l [ l Activity No. ______ _ Approval Date: ____ _ Design Issues 2.0 Design & Geometric Requirements ROAD CLASSIFICATION TABLE Name of Roadwav KCRS Classification 2.03C 2.03D 2.03E 2.03F 2.03G 2.03H 2.03! 2.03} Maximum Superelevation (2.05) Horizontal curvature (2.05) Maximum grade (2.11) Stopping Sight Distance (2.05, 2.12) Entering Sight Distance (2.05, 2.13) ' Minimum pavement width (Note: Footnote 9 -Neighborhood collectors require 36-feet at approach to intersections with arterials) Minimum roadway width Minimum R/W width Page 13 of 15 Updated 04/07 Activity Number: ______ _ 1993 DESIGN REQUIREMENTS (cont.) [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l 2.03J Min. R/W width (Footnote 12 and 2.198 -include 1 foot extra ROW behind curb or sidewalk) 2.03K Curb or shoulder type road (2.01) 2.03L Minimum Half-Street width 2.06 Private Street Design Standards 2.0687 Verify maximum potential of 16 lots 2.07 Half Streets 2.08A Minimum Cul-de-Sac diameters 2.08B Maximum Cul-de-Sac length 2.08E Maximum Cross Slope 6% 2.08F Bulb island shall be offset 2-feet 2.09 Alleys 2.098 Private Access Tracts (Note: Must meet all standards for minor access street, except cut driveway design is allowed with property line radii dedication) 2.lOA 2.lOA 2.IOA 2.108 2.IOC 2.lOE 2.1 IA 2.118 2.120 2.16 2.18 2.20 3.0 3.01 3.01 3.02A 3.02B 3.05 3.09 3.10 3. 1 1 4.0 4.01 4.0lF 4.0IF 4.02 4.02 4.03 4.05 5.0 5.01 5.02 5.03 Angle of intersection between 85 and 95 degrees Intersection curb radius Intersection right-of-way radius Intersection spacing Intersection landing Low Speed Curves Maximum Grade -Use AC for grades >12%, Use PCC for grades >20% Grade Brakes -maximum I% at intersections Intersection stopping sight distance (125' SSD allowed for local access streets) Bus zones -For arterials and neigh. collectors, the designer shall contact metro. Intersections with State Highways Single access serving more than I 00 lots Driveways, Walkways & Trails Driveways Joint Use Driveways Sidewalks (both sides for subcollectors and higher classification) Location and width Handicapped access ramp (Use updated detail from KC Road Engineer, 3/26/04) School Access -asphalt walkway, sidewalk, or delineated shoulder. Bikeways Equestrian Facilities Surfacing Road Section and Surfacing (Drawings 1-001 --1-006) Note: Neighborhood collectors require 3-inch asphalt concrete Perform saw cut of pavement at fog line. Pavement overlay for widening and channelization (show special note as approved by Development Engineer -see web site) Residential street design Poor subgrade evaluation Arterial pavement design Pavement markings, channelization, and tapers (Requires DOT review) Roadside Features Rock facings (Dwg. Nos. 5-004 -5-007) Side slopes, generally 2H: lV Street trees and landscaping Mail boxes (Dwg. Nos. 5-010 -5-012) Street illumination Survey Monuments to be disturbed are shown Roadway Barricades curb 5.04 5.05 5.06 5.07 5.08 5.11 Bollards for walkways or maintenance roads Roadside obstacles (Note: If variance required for utility ·pole, the utility company must 6.0 6.02 6.03 apply for the variance. , Bridges Bridges (minimum width 28-feet) Approach slabs Page 14 of 15 Updated 04/07 Activity Number: ______ _ 1993 DESIGN REQUIREMENTS /cont.\ [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l [ l 7.0 Drainage 7.02A-D Grass-lined, pipe or rock lined, special designed ditch 7.03A Minimum pipe size 12-inch diameter 7.03L Beveled ends for culverts in ROW 7.04A Maximum spacing between catch basins 7.04B Inlets not allowed for collecting water from road surfaces. 7.04E CBs taller than 5' (grate to invert) are Type II, Max. depth 12-feet per Dwg. 2-005 Deeper pipes require Manholes in Dwg. 2-007 through 2-0 IO ' 7.05A Vaned grates 7 .. 05B Through curb inlet frames for sag curves and intersections> 4%. Notes: a) Through curb inlet shall not used on rolled curb, b) See web site for policy on flanking inlets. 7.05D Use round locking covers for new catch basins in roadway which do not collect runoff. 7.05E All covers and grates shall be locking 7.0 8.02 8.03B Utilities Utility pole locations and other obstacles. Open cuts on existing roadways, patch requirements NOTES: Page 15 of 15 Updated 04/07