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LUA-07-032_Misc
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Renton City Limits Parcels SCALE 1 : 1,814 Renton 100 0 100 200 300 FEET http ://rentonnet.org /MapGuide/maps/Parcel .mwf EXHIBIT 3 N A Thursday, June 2 1, 2007 1:52 PM CHAD ARMtk.JR, .LLC October 26, 2010 Job No. 10-007 Mr. Michael Gladstein American Classic Homes 2821 Northup Way, Suite 100 Bellevue, Washington 98004 Subject: Wetland Hydrology Report Rosewood Highlands Project Renton, Washington Dear Mr. Gladstein: 6500 126'" Avenue S.E. Bellevue, Washington 98006-3941 (425) 641-9743 Office (425) 643-3499 Fax .----'? chad@chadarmour.com ----- We are pleased to present the results of our wetland hydrology assessment for the above-referenced property located in Renton, Washington. The work was accomplished in accordance with our proposal (No. 388) dated October 25, 2010. BACKGROUND INFORMATION We understand that in their May 12, 2008 plan review letter, the City of Renton (City) asked for additional stormwater management information. Among other things, they asked that you address potential impacts to wetlands as a result of the proposed project. Specifically, they requested that the analyses address both existing and development wetland hydrological conditions and follows Guide Sheet 2B Wetland Hydrology Protection Guideline in the reference section found in the 2005 King County Design Manual. Our analysis utilized information gleaned from our February 26, 2007 critical areas assessment and delineation report as well as reports and drawings provided by ESM Consulting Engineers (ESM). Wetland The on-site wetland is a part of a larger wetland located off of the site to the north (Attachment A-Figure 4). It appears that the eastern lobe of the area shown on Figure 4 is not a part of the wetland given that this area is now the location of off-site stormwater management ponds. The on-site portion of the wetland covers 1,543 square feet (sf). Although we did not survey the entire wetland, based on the information provided by ESM and found on the King County iMap for Parcel No.518210-0022 (the parcel that contains the wetland), it appears the wetland covers an estimated 50,000 sf. Hydrology The site is located at the upper reaches of west branch of Maplewood Creek, which flows south along the eastern portion of the site. The drainage basin upgradient of the site drains a small area bounded by NE 4th Street (north), Union Street (east), and the Post Office (west). This basin includes two smaller on-site sub-basins, both of which discharge to Maplewood Creek (Figure 9). Most of the site (->90%) drains to C:IESM/Rose/Wetland Hydrology Report.doc Chad Armour, LLC 10/26/10 Wetland Hydrology Rep Renton, Washington 11100d Highlands Project Maplewood Creek and the remaining about <10% of the site drains to the wetland which in-turn drains to Maplewood Creek. Portions of Lots 20 through 23 are located in the sub-basin that currently drains to the wetland (Figure 10). We understand that with the exception of Lots 24 through 27, all of the precipitation that falls on impervious surfaces will be directed to the stormwater vault. Precipitation that falls on the roofs and rear yards of Lots 24 through 27 will bypass the stormwater management system and be directed to the stream. Soils The King County soil survey indicates that the site supports one soil type, Alderwood gravelly sandy loam. Alderwood soils are made up of moderately well drained soils underlain by a dense till layer typically two to 3.5 feet (ft) below the surface. The geotechnical engineering report confirmed that glacial till underlies the site, but to a depth ranging from 5 to more than 10 ft below the ground surface. The same report indicates that the north and eastern portions of the site have been filled with 3.5 to 9.5 ft of fill, including all or part of Lots 17 through 27. Analysis Using the King County Runoff Time Series (KCRTS) method for estimating runoff, the City will require 44,286 cubic feet (cf) of storage to handle the impervious surfaces that will _be created by the project. We understand that the actual capacity of the vault _ 1 -\ designed for the proJect will be 45,989 cf. / / The estimated runoff for the Rosewood Heights project pre-and post-develop~ for three different storm intensities is shown on the following table. The post-development numbers are for the entire site, including the runoff from the parts of Lots j2'through 27 that will be directed to the stream, or about <1 % of the totals. These pre-development estimates are conservative estimates because the model assumes that the site is occupied by a mature Douglas-fir (Pseudotsuga menziesil) forest. The site is actually represented by about a half a dozen structures and associated driveways (impervious surface), as well as mowed lawn, blackberry (Rubus sp.) brambles, and patches of deciduous forest. Thus it is likely that more runoff currently leaves the site than suggested by the model. Never-the-less, the City requires discharge runoff from the post-development site at the same rate as those shown pre-development. Therefore, the sensitive areas will have no increase in the peak flows vis-a-vis' pre-development conditions. Estimated runoff from the Rosewood Hei Condition Pre-Developmentb Post-Develo ment ear 0.12 cfs 0.70 cfs ' data provided by ESM Consulting Engineers ' assumes forested conditions C:/ESM/Rose/Wetland Hydrology Report.doc Chad Armour. LLC 0.20 cfs 0.84 cfs 2 0.35 cfs 1.42 cfs 10/26/10 Wetland Hydrology Rep Renton, Washington Conclusions 11100d Highlands Project Hydrological input to the wetland from the site is limited to that sub-basin that drains to the wetland. Since this portion of the site will largely remain pervious surface (i.e., the backyards of Lots 20 through 23), we assume that the precipitation that falls on this sub- basin will continue to drain to the wetland as it currently does. This includes sheetflow and groundwater discharge. Groundwater discharge will result from water percolating through the soil profile and leaking out of the cutbank. As such, site development should have no detrimental hydrological effect on the wetland. Similarly, the off-site portion of the wetland will not likely be affected by site development because the wetland is located upgradient from the site. That is, hydrological inputs to the wetland north of the site, including precipitation falling directly on to the wetland and runoff from property west, north, and east of the wetland, will be unaffected by site development. Because there will be little if any effect on wetland hydrology from the site post- development, the development should have no cumulative hydrological effect on the wetland. Similarly, because the stormwater captured on the site, detained in a stormwater vault, and released per the requirements of the stormwater design manual, we anticipate no cumulative hydrological effect on the watershed. LIMITATIONS Work for this project was performed, and this letter report prepared, in accordance with generally accepted professional practices for the nature and conditions of the work completed in the same or similar localities, at the time the work was performed. It is intended for the exclusive use of American Classic Homes and their assigns for specific application to the referenced property. This report is not meant to represent a legal opinion. No other warranty, express or implied, is made. It should be noted that Chad Armour relied on information provided by others indicated previously. Chad Armour can only relay this information and cannot be responsible for its accuracy or completeness. Also note that assessing wetland hydrology is an inexact science. Biological professionals may disagree on the mechanics of this function. Accordingly, the wetland hydrology assessment performed for this study, as well as the conclusions drawn in this report, should be reviewed by the appropriate permitting authority prior to committing to detailed planning and design activities. C:/ESM/Rose/Wetland Hydrology Report.doc Chad Armour. LLC 3 10/26/10 Wetland Hydrology Rep Renton, Washington wood Highlands Project Any questions regarding our work and this report, the presentation of the information, and the interpretation of the data are welcome and should be referred to the undersigned. Sincerely, Chad Armour, LLC Chad Armour Principal Attachments: References Attachment A -Figure 4 -Figure 9 -Figure 10 C:/ESM/Rose/Wetland Hydrology Report.doc Chad Armour, LLC 4 10/26110 Attachment A en~ ! ~ 9~ z .. "'" Ou ;§ ~ li 0 y.o: ~ 0 ~ t N ~ ;;;~ ~; ~n WO /_ •o ~N z-.._ ~~ ~---Eo ti ii 0 ~o:: '· ' _:,,,,y---+;.-- ' -,-- ;,' J ( ' -.. \ JE,23059021 1 -(---==--)' / ,· --~ ---.\ -r=~~ --~(-\ ~,~ /---/·1 ', ) 11 ( i '·, ' 16230590811 · ) ( i \ ·1 ,l~'°i' (/ . ' I ' . ' -. I !\ lie23d_s~;89 I/ I I i -··-r'7J / \,_) "' \ I · \ ! 16C3059De,?._ ' \,j f-,.c:"~_ --. ' ( !I -~--' '-tt.23059D?3 ~'-·--........ "\. h~ a;.~+----t---;c)----)--· --,.. \ 1\/1' /- . 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( /---i ]52 'I '---1/ I // -....... f 15a' ·059193 _l} J !523D59035 -- 1--/ I :05'::ll'::'C 152 1523 152305';1030 NYD__'.: ,_ \ 152305',l84J (, ----~-~. -l--+---1 _/-f 0 f,7; ' 11,~'<\ \. L,,·\ I 'I_ . \ )! ~-. ~< ' (l_ <( ~ z -Cf) <( Cl) w I- Cf) LL LL 0 ~It CJ)* a:-~-z_ 0 ~ Z N LU § "' ~ M VO 0 z 0, iil -32 Ol f--w ~ ...J ... 3:: "' =i E ~ (/J ~ ~ ~ ~ ~ CJ 1o i r" ::!88 ;;;&~ t~~ ,;;-'ii,',;,' RE-e i ~ ~s· ~~@ (J) 0 z <!'. _J I (!) -~ I w 0::: 0 ::, 0 ~ 0 s w (J) 0 a: ' , " ~ " ~, ·~ <( C 0 S' g. "0 " 00 33 11 I~ ~· C ~ E 'f J 1~1~ Q VI.,.. Ci 1/1 (J 0 _: 1?} ·-0 ... 2: ..JO. lJ E "' w ~ ~ ~ .f ' " ,~ C c ·-' ~· w -~ 1 :g u• ~ I 0 File: \ \EsmB\ENGR\ESM-JOBS\ 1352\001 \006\exhibita\EN-05.dwg Plotted: 10/26/2010 4:lJ PM Plotted By: Trevor Stiff ,.-., [] < () r- 0 ··, / '~------ U1 0 "' U1 0 U1 0 0 0 (/) () )> r m ..... = II 01 0 ··---.--,.-----=~-=--- CONSULTING ENGINEERS L LC 181 S 333rd St. Bldg C, Suite 210 I • I * I t:.74 I Fecleral Way. WA 98003 ...,. www.esmcivil.com F'EOERAI.. 'Nl<Y l"'l 638-6113 E'wERETT 425 297-9900 ULE,-S8URC !:109 962-2606 Civil Engineering Public Works JOB NO. 1JS2-00!-006 DRAWN: ECN Land Surveying Project Management DATE: 10/26/2010 SHEET T OF 1 Lond Planning Landscape Architecture 4-oo j s:::: ~ r ~ 0 0 C, () -;:o l"1 l"1 ;,;: j --404---- i/ --r I : I I k lg ·\~·. I . '( I / : < I :1·/. / ---. -~~C"C--=-----------.. I I .... 1 ' • / \ / EXISTING HYDROLOGY MAP -, ., I I ROSEWOOD HIGHLANDS FIGURE 9 • en =I l"1 ID 0 C z C, )> ::0 -< l=ile: \ \Esm8\ENGR\ESM-J0BS\ 1352\001 \006\e~hibits\EN-06.dwg Plotle<f: 10/26/2010 1:52 PM Plotted By: Trevor Stiff 0(,)UUr 000000 00 00 ---i1-,-~+-i-f--~+-l--+-+-1-1 l-l--++-1-+--t-1-L-1--+--++- 1-t--++-'I-+-+ ,-~I_ -+-t-rl--t-+--"-,--+-+-+-++-+-+- CONSULTING ENGINEERS LLC 181 S 333rd St. Bldg C. Sui1e 210 I • I & I O!M I Federal Way. WA 98003 • .... FEDERAL W/,.Y (253) 53"-151 lJ www.esmcivil.com EVERETT (~25) 297-9900 El.L.ENSBUl'J:. (~9) 962-2608 Civil Engineer;ng Public Works J08 NO. 1352-001-006 DRAWN: ECN Lond Surveying Project Monogement OATE: 10/26/2010 SHEET 1 OF 1 Land Planning Londscopa Architectur,:, •<So ..... -'' ' ..._ .. ..:::., ' --' 00 --, 0 0 0 0 0 e -, 0 0 0 C 0000 - 10000( 000000 ,000000 ·,oo 0000. 00(,0000 ,000000 ,o,_ rJ O O O O C O O l ' 1 " ' ' -, 000000)00( 100000( 0 0 Cl 0 ' ' ~' ! ~ --, '' ' ' i ~ ' ' .. ' _, ' ,,. ... ~---- C 0 z ., 0 ., ~ (/) =i fTI fTI r- 0 );,. -0 ;;o fTI fTI 0 );,. );,. 0 ;;o ;;o fTI ~ );,. z z G) --+ 0 (/) --+ 0 ;;o ;;::: ::;; ~ fTI ;;o :i;; C r::::j );,. ;;o fTI );,. CD --< -0 );,. (/) (/) z G) (/) --+ 0 ;;o ;;::: ! fTI ;;o :i;; C r --+ f ' ' );,. ;;o ~ 0 ;;o );,. z z G) --+ 0 (/) --+ 0 ;;o ;;::: ::;; ~ fTI ;;o :i;; C r --+ (/) ~ !D 0 C z §i? ~ r:: f ' f ' ' ' ' ' ' 3:::: ' '~ r- ' ~ 0 0 0 () ;;o ITI ITI " r m G) m z 0 (JI 0 "' (JI 0 (JI 0 0 0 (fJ () )> r m ...a. : II (.11 0 a ~,a~ ::::: DEVELOPED HYDROLOGY MAP ROSEWOOD HIGHLANDS FIGURE 10 CHAD ARMOUR, LLC February 26, 2007 Job No. 07-001 Mr. Michael Gladstein American Classic Homes P. 0. Box 1830 Renton, Washington 98055 6500 1261" Avenue S.E. Bellevue, Washington 98006-3941 (425) 641-9743 Office (425) 643-3499 Fax chad@chadarmour.com DEVELOPMf: CITY 0F;~~%NING Subject: Critical Areas Assessment and Delineation Rosewood Highlands Preliminary Plat Renton, Washington MAR 1 6 2007 RECEIVED Dear Mr. Gladstein: We are pleased to present the results of our critical areas (wetland and stream) assessment and delineation for the above-referenced property located in Renton, Washington (Figure 1). The work was accomplished in accordance with our proposal (No. 241) dated January 3, 2007. The purpose of the work is to assist you to identify the size and location of wetlands and streams on the subject property. The report is organized in sections and includes: SUMMARY OF FINDINGS that presents a synopsis of the pertinent issues related to wetlands and streams; SITE DESCRIPTION of the subject property (site) and adjacent properties; BACKGROUND INFORMATION that presents existing information about the site and surrounding area; SITE CONDITIONS that describes wetlands, streams, and uplands; CONCLUSIONS that summarize the results of our critical areas assessment and delineation; and LIMITATIONS of this project. References, tables, figures, and appendices follow the text. Table 1 lists the plants observed on and near the site. Figure 1 is a Vicinity Map showing the location of the site and pertinent surrounding features. Figure 2 is a Site Plan that shows the location of wetlands, streams, sampling points, and other pertinent site features. The soil type mapped for the site is shown on Figure 3. Appendix A contains assessment methods and field data forms. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour. LLC · 02126107 Critical Areas Assessment and Delineation Renton, Washington SUMMARY OF FINDINGS Rosewood Highlands Preliminary Plat American Classic Homes proposes to develop the 4.39-acre (ac) site so that as many as 27 homes can be constructed. Most of the site is upland. A total of 1,543 square feet (sf) of the site is occupied by a Category 3 wetland. Most of this wetland is located off of the site. The standard buffer for Category 3 wetlands is 25 feet (ft). A Class 4 stream flows across the site along its eastern boundary. The standard buffer for Class 4 streams is 35 ft. SITE DESCRIPTION Site The 4.39 ac site is located at 224 Union Avenue in Renton, Washington, in Section 15, Township 23 North, Range 5 East, Willamette Meridian (Figure 1). The site, which occupies six parcels (Nos. 518210-0068, 518210-0069, 518210-0073, 518210-0079, 518210-0081, and 518210-0085), is the location of several single-family homes, mowed lawn, forest, and a stream. Site elevations range from about 384 ft where the stream leaves the site to about 410 ft above mean sea level near the western edge of the site (ESM Consulting Engineers LLC, 2007). Adjacent Properly In general, the area in the vicinity of the site is represented by single-family residences. To the east are new homes on small lots. Homes on medium-sized lots and NE 2"d Place are located south of the site. A park that is under construction is located to the west. A wetland and property in the process of being filled are located north of the site. A relatively new stormwater pond is located on the property being filled. BACKGROUND INFORMATION The following sections of the report portray known available information about wetlands, streams, and other information about the site and surrounding area. Site Development Plan We understand that American Classic Homes plans to divide the site so that up to 27 single-family homes may be constructed (Figure 2). Wetlands and Streams The National Wetland Inventory (NWI) map shows no wetlands on or near the site (FWS, 2007). The King County iMap shows an unclassified stream flowing across the site. The same map shows a wetland located about 1,500 feet (ft) east of the site (King County, 2007). The Washington State Department of Natural Resources (DNR) Forest Practice Activity map shows no stream on the site. The same map shows a fish-bearing stream about 500 ft southeast of the site (DNR, 2007). The Streamnet map also shows no stream on or near the site. The closest stream mapped by Streamnet is the Cedar River (Streamnet, 2007). The City of Renton's (City) Storm-Surface Water map shows a C:/ESM/RoseNVetland Delineation Report.doc Chad Armour, LLC 2 02/26/07 Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat stream (Maplewood Creek) originating north of the site immediately south of NE 4th Street (Renton, 2005). Soils The King County soil survey indicates that the site supports one soil type, Alderwood gravelly sandy loam, 6 to 15 percent slopes (Figure 3). Alderwood Soil Series Alderwood soils are made up of moderately well drained soils underlain by a dense till layer typically two to 3.5 ft below the surface. Alderwood soils formed in glacial deposits under conifer trees. In a representative profile, the surface layer is dark brown (1 OYR 4/3) gravelly sandy loam about 12 inches (in) thick. The subsoil is grayish brown (2.5Y 5/2) gravelly sandy loam (Snyder et al., 1973). Till is a barrier that retards the downward percolation of the rain that falls on the soil. When the soil above the till layer becomes saturated, water that accumulates on the till surface will pool in depressions or flow in the direction of the gradient. The general subsurface flow is ultimately concentrated in depressions or streams. Alderwood gravelly sandy loam is not a listed hydric soil (NRCS, 1996). SITE CONDITIONS We visited the site on January 22, 2007 to assess upland, stream, and wetland conditions on and adjacent to the site. The following sections of the report describe the upland and wetland plant communities located on and/or adjacent to the site and the physical attributes of the stream. Uplands At least four upland plant communities are present on the site. Most of the site is represented by mowed grass and associated ornamental landscaping (Appendix A; Plot ID SP-2). This area represents the relatively flat western 80 percent of the site. Smaller areas of the site are occupied by deciduous forest, Himalayan blackberry, and reed canarygrass (Table 1 ). Deciduous Forest The forested plant communities are located in the southeast and northeast corners of the site. In the southeast corner of the site the plant community is the location of widely scattered black cottonwood, big-leaf maple, western red cedar, and red alder trees. Growing under the tree canopy are a thick tangle of Himalayan blackberry shrubs and some hazelnut, Scot's broom, hardhack, and vine maple shrubs. The plant community in the northeast corner of the site has black cottonwood rooted at the top and toe of the slope (the toe forms the southern edge of the adjacent wetland). Widely scattered big-leaf maple and red alder trees are rooted on the slope as are a thick tangle of Himalayan blackberry shrubs and the occasional clump of Japanese knotweed. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC 3 02/26107 Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat Himalayan Blackberry Plant Community The moderate slope east of the mowed lawn is covered with a thick tangle of Himalayan blackberry shrubs. A few black cottonwood trees are also rooted on the slope. Reed Canarygrass Plant Community The 30-feet-wide ground east of the Himalayan blackberry plant community and west of the on-site stream is the location of a reed canarygrass plant community. Also present are some encroaching Himalayan blackberry canes and the occasional hairy cat's-ear, soft rush, and western water hemlock. This area is regularly mowed presumably as part of a maintenance program. The plants are rooted in very sandy very gravelly fill soil. The soil was saturated to the surface (Plot ID SP-1). Streams The west branch of Maplewood Creek flows across the site along the site's eastern boundary. Although this stream has been around for a long time, it clearly has been manipulated by humans in the recent past. It originates from a large pipe located under NE 4th Street. From there it flows through a wetland, most of which is located on the property north of the site. It then flows across the site in an engineered channel. A near vertical slope forms its eastern bank and fill associated with a buried sewer pipe its western bank. The stream continues to flow south of the site in a fairly linear fashion. We did not observe fish in the stream. On the site the silt-bottomed stream averages 7.8 ft wide (range 5 to 11 ft) and 14.1 in deep (range 6.5 to 21 in). The east bank of the stream is draped with Himalayan blackberry shrubs. The west bank supports the mowed reed canarygrass plant community. The mowed area averaged about 30 feet wide. Stream Classification and Buffers Based on the physical characteristics of the stream and the setback for the adjacent residential development to the east, the on-site reach of the west branch Maplewood Creek is classified as a Class 4 steam (RMC 4-3-050L 1 aiv). The standard buffer width for Class 4 steams is 35 ft (RMC 4-3-050L5aic). Wetlands We flagged one wetland on the site and ESM Consulting Engineers surveyed the flagged wetland boundaries. The west branch of Maplewood Creek flows through the wetland. This riverine forested wetland (Cowardin et. al., 1979) is a part of a larger wetland that· extends off site to the north. It supports widely scattered black cottonwood and red alder trees ranging from about 12 to 20 in in diameter. Western crabapple, red-osier dogwood, and hardhack shrubs grow under the tree canopy. Small stands of reed canarygrass occupy flats adjacent to the stream. The on-site portion of the wetland covers 1,543 sf (Figure 2). What appears to be a temporary stormwater facility is located about 25 ft east of the wetland. C:/ESM/RoseNVetland Delineation Report.doc Chad Armour, LLC 4 02/26/07 Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat Wetland Functions, Classification, and Buffers We performed a functional assessment of the wetland using the Washington State Department of Ecology's (Ecology) wetland rating form for western Washington (Hruby, 2004). When we examine their individual attributes, the wetland provides high water quality functions, and moderate hydrologic and habitat functions. Based on the criteria set forth in the City's municipal code and the buffer associated with the stormwater pond to the north, the wetland meets the criteria for a Category 3 wetland (RMC 4-3- 050M1 aiii). The outlet of the wetland has been modified. Fill associated with a buried utility line has narrowed the outlet. The standard buffer width for Category 3 wetlands is 25 ft (RMC 4-3-050M6ci). CONCLUSIONS Most of the 4.39 ac site is upland. A part of a Category 3 wetland is located in the northeast corner of the site. Most of this wetland is located off of the site to the north. A Class 4 stream flows across the eastern edge of the site. The stream flows through the wetland. LIMITATIONS Work for this project was performed, and this letter report prepared, in accordance with generally accepted professional practices for the nature and conditions of the work completed in the same or similar localities, at the time the work was performed. It is intended for the exclusive use of American Classic Homes and their assigns for specific application to the referenced property. This report is not meant to represent a legal opinion. No other warranty, express or implied, is made. It should be noted that Chad Armour relied on information provided by others indicated previously. Chad Armour can only relay this information and cannot be responsible for its accuracy or completeness. Also note that delineating wetlands and streams, and assessing functions and values are inexact sciences. Biological professionals may disagree on the precise location of wetland and stream boundaries, their functions, and classification. The final determination of these characteristics is the responsibility of the permitting authority. Accordingly, the wetland and stream assessment and delineation performed for this study, as well as the conclusions drawn in this report, should be reviewed by the appropriate permitting authority prior to committing to detailed planning and design activities. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC 5 02/26/07 Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat Any questions regarding our work and this report, the presentation of the information, and the interpretation of the data are welcome and should be referred to the undersigned. Sincerely, Chad Armour, LLC Chad Armour Principal Attachments: References Table 1 -Plants Identified on and adjacent to the Rosewood Highlands site Figure 1 -Vicinity Map Figure 2 -Site Plan Figure 3 -Soils Map Appendix A -Assessment Methods and Routine Wetland Determination Data Forms C:IESM/RoseNVetland Delineation Report.doc Chad Armour, LLC 6 02/26107 Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat REFERENCES Cooke, S.S. 1997. A Field Guide to the Common Wetland Plants of Western Washington and Northwestern Oregon. University of Washington Press. Cowardin, L. M., V. Carter, F. C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Department of the Interior, Fish and Wildlife Service, Office of Biological Services. DNR (Washington State Department of Natural Resources). 2007. Forest Practices Application Review System for Township 23N, Range 5E, Sections 15. http://www3.wadnr.gov/dnrapp5/website/fpars/viewer.htm. Ecology (Washington Department of Ecology). 1997. Washington State Wetlands Identification and Delineation Manual. Publication No. 96-94. 88 pages plus appendices. Environmental Laboratory. 1987. U.S. Army Corps of Engineers Wetlands Delineation Manual, Technical Report Y-87-1, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. ESM Consulting Engineers. 2007. Preliminary Plat. Job No. 1352-001-006. FWS (U. S. Fish and Wildlife Service). 2007. Wetlands On-line Mapper. http://www.wetlandsfws.er.usgs.gov. Hitchcock, C. L. and A. Cronquist. 1973. Flora of the Pacific Northwest. University of Washington Press. Hruby, T. 2004. Washington State wetland rating system for western Washington - Revised. Washington State Department of Ecology Publication# 04-06-025. King County. 2007. iMap. http://www5.metrokc.gov/servlet/map output.him. NRCS (U.S. Department of Agriculture Natural Resources Conservation Service). 1996. Hydric Soils of the United States. http://www.statlab.iastate.edu/soils/hydric/national.html. Reed, P. 8., Jr. 1988. National List of Plant Species That Occur in Wetlands: Northwest (Region 9). US Fish and Wildlife Service, Biological Report 88(26.9). 89 pages. Renton, City of. 2005. Storm-Surface Water map. Planning/Building/Public Works. Renton. 2005a. Title IV Development Regulations, Chapter 3 Environmental Regulations and Overlay Districts, 4-3-050 -Critical Areas Regulations, Snyder, D. E., P. S. Gale, and R. F. Pringle. 1973. Soil Survey of King County Area, Washington. USDA Soil Conservation Service in cooperation with Washington Agricultural Experiment Station. 100+ pages plus maps. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC 02/26/07. Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat Streamnet. 2007. NWR Critical Habitat Mapper. http://www.streamnet.org. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC 02/26/07 Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat big-leaf maple black cottonwood grass hairy cat's-ear hardhack hazelnut Himalayan blackberry Japanese knotweed red alder red-osier dogwood reed canarygrass Scot's broom soft rush vine maple western crabapple western red cedar western water-hemlock Hypochaeris radicata Spiraea douglasii Cory/us cornuta Rubus discolor Po/ygonum cuspidatum A/nus rubra Camus stolonifera Phalaris arundinacea Cytisus scoparius Juncus effusus Acer circinatum Ma/us fusca Thuja plicata Cicuta dou lasii Refer to Appendix A for an explanation of Indicator Status. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC FAGU FAG FAGU FAGW FAGU FAGU FAGU FAG FAGW FAGW FAGU FAGW FAG- FAGW FAG OBL 02/26/07 "Tl = C ii Source: The Thomas Guide, 2002, King/Pierce/Snohomish Counties; Page 656. 1 :~ NOTTO SCALE l -~ .__ ________________________________________ _J ; l FIGURE 1: VICINITY MAP Chad Armour, LLC 6500 125• Avenue SE Bellevue, Washington 98006 jl' j ,__ ___________________ ,1_ __________ ....J Rosewood Highlands Preliminary Renton, Washington ) ·, ii . .z l!J-:,~ z~ wie >~ -,: oc z~ oe z :, J ;' / ( -------~~-------- ----:--.. -, ·408 ·;·;,RACTA 20\:·lJ.U.0. " ·:-..-'·· · .... J(\tj~.· T~T.8 26 PUB9lt!ffP. ef' ;:r,.~ ' \ " ,· ···101 18 TRACT 20' J.U.O -t10~.f -~-:·.: . ::.:~~): 6 ~:/S~ _ . j; 9 1 i.l I 'rl .r,··· .. ··"·· ·······.··· . , I . n·; ..•... i ,1 I •'" , . ·.. -~·.·.;: . ~ ; ! /8 ;),,'ti!:/~ ··;, >:·2 4 19 ,, • J / '3 /"~ .. ,· L ... 1 '"~~; i :: ·, ___ :-.----~---_l~-~.~----~~.::~;-~:~--~-tr;;~~,J:~·~~ ~! ....... (, f.J... ' ' ~~c;~~~1~f~- ,i NE2Nj..PLACE :--; -~ _. (PRIV .. ~_OAO)_ I • .. i, /!l s . ..,... '"'.' 9 ~' . ..., rr~~ ,l. >r • SP-1 Sampling Number and Approximate location Source: ESM Consulting Engineers. il,;ft: ~/IJ? -•pniJact\ai..~ ~\--'1¥-~.d .. 20· ·"' / / / -+-, / ! ~;. ftt i . ~ J!, t·· \,, ,? \~ if ... ,.\:-:.:-·-.. ·:, "WI" '"' • • • i()iJ"'ETLANI) • , · '"""'""" ..... ,,, "'--:.,)~... . . .,, """" 1-~·~ :;· '..~.: .. :.: :: ~.~19 ·11\· I " ·'"' '. ~-•· . .1 I I ' ...•. T~F S£°N1!T1VE AREA . 21 15, 14 11 10 ··-·--+·· "n ,- ~ 22 :a ', " ·' 13 ...... ,,12 \\\' "~ i 23 /')24 : ' ' ' ' ' ' .. f. .. • . ~.,,/ Ji / ' l' 1: =-'c!1!('· . 25 f~---· .\ii: 26 esP-2 " o·~ f-< u·s 27 ,,, ' : -· 35' Buffer! I I -,:m r£ .:. -! ~~ !.f . if I ~,-~-N if 'ri · .1 i 1 SP-1 I 1. cw kic,5., .... ,i_:,~· .··-,-------·· a TRACT E STORM VAULT , I J I 1: I I\. \ I~ I I I' : 1n 1 -----,·--;:~~:-11-'"!?; • ~0000 i,Y~J ~,,o 1,0~~ ~~ .._1.0'1'-- '~0 Cl' Q ·' N <?/' 0 ~o•'"' ~"""' & ., ;f;. I' I I I I 0~ 0 50 Scale in Feet 100 FIGURE 2: SITE PLAN R~ Hl{tllandS Preliminary Pia! Renton, WastikigtPn Chad Armour, LLC 6500 126'1 Avenue SE Bellew,,, Washlng!On 90006 ~ ,!!! AgC -Alderwood gravelly sandy loam, 6 to 15 percent slnpos 0 1 Source: http://www.or.nrcs.usda.gov/pnw _ soil/wa _reports.htrrd NOTTO SCALE I m g._ ___________________________________________ .J i FIGURE 3: SOILS MAP ,'!! 5 Rosewood Highlands Preliminary Plat, Chad Armour, LLC 6500 126" Avenue SE Bellevue, Washington 98006 ~ . .__ ___________________ .J..._ ________ _J Renton, Washington ,, ! I e,<5' o· -------\ -----------oo ', \, 18 I \, I t 17 I 19 21 ~"'~' L .....J Ii I TR~CT B I \•.._'T\>, .. -•;:r,• 1 \ 20 J.U.D. t.\·.'>'*•"'..~... ' -' t~ t J •\ •• ,/:,:f ...J o::,;;; lr \-_____ ......_ ----,u. =.m:t,------'•o -o~~r....... LJ • • ·-13 ,,.. • • V ••• •,,: r· \ . .... ... ,,; -,._ ---------:t<:· _.,. ~-V ..._ a ~ ( • ..... ......,,.--, .. · •.••. ·<Y.-a.. -.a-. " "[~··r.):\~:-rl? ;1.r~.'!1~· },Jtc:&:!. ~s; . "(Ill-=~.::-.... ~ 1· 1 ·-~, , .. , ,~·· ii;.:.; ....... --, ...:;_"G;, ,--, '1 -...,::;: \ I .. ...,. \* ;;:.;,.-S,,I ,-_. / -~· !II J , ----,-~~. ~ I ---\ ACT A / -, I I .,~-U.D. . __ J ,'; . -.. i----·f-! ·· T / ~ 1 -~ ... f ' '\. t , !1':. A -1 _., .. I : j 11, 1 t_JJ 1 ;, J '"' '@'" ,$"'-.• 1 'I V i • f. ,:=: L:.J ,,._ • 9 J I !~ I 5. i ~_,,~· } ijj' V l I : i '! ,.... .. / 7 I --- / 15 / / /' L I I /14 ~ ( 'It 2 0 .. I \ 23 \ :a_ __ -------·----;, 8/ -::,," ~ :jt __ 13 >• .J .. I ' I \J ! ( ' ".,~; l t I / e SP-~ I, \ l ! \ : f ' J i \ I i • l I l I / I I I \ ' : l 1!1 LB ~~ fl r~41 I \~ ' ~ ..J . L ,., 11 ../ !~ \ \ \ I <l ;I \ \ )'.:. I/ .. I :J:;;! z ffi w >-> ~ <( "' 0 z~ 0~ z :J -·- 1 ,/\ 1/ \ v I .. I I I • • I /9 , , / ! -:/ !/ / { 1 ./ 4 r ' · . . ., . / ,r_'' ,· ·--,sJ;J,12 r:;m{),.?,:;,1 j \ ' -~-~.:.----~-10 ~-------i;:;" ( /' // \ _ _,_ __ o ,_ _,, ___ -,. _..--, (. l A ..._ -""--~-{----<; S_~l>-·L"". . ---~ "·' 'I-I ~ot.C,1:'/ \ : ' • -;,. ~-~ o ;(""NE _ / .. _.. ~ , ~ I ) , fE::··" .ii . I _L t' ---. c:---. . ' _., .. -, ~ . ' -"' L_j 'C --'"> r---~ ---' <--\.:)'-'-. ,;s:, --.,.,,.,,.--..3_ -;:---1',@ -= " -~ ----,. O> ., ~ I P") fO --'---J--~ ,.z.. - • SP-1 Sampling Number and Approximate Location e,<5' n_,-\ 0 1.0""'"*"'" ". ,:.'-o"' 0~ ~<;; 0 50 100 Scale in Feel ;:::!-.. ' FIGURE 2: SITE PLAN Rosewood Highlands Preliminary Plat Renton, Washington Source: ESM Consulting Engineers. OA TE\ 02/22/07 1: 24Dm -' C: \prO,iect\Ctienls\armour\Americor, Clossic\Rosewood Highlonds\AmCIRoseHtOl.dwg <.1_,'0 ~(0,; <,;\ \'J yv n_,-\ 0 1.0"'~ " . ,:.'-o"' '~s ,S' o N LOPME\yy PLA/~J91N(, j I ITYOF - MAR 1 ~ 2007 RECEIVED Chad Armour, LLC 6500 126th Avenue SE Bellevue, Washington 98006 Assessment Methods Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat ASSESSMENT METHODS Chad Armour reviewed, City of Renton (2005), King County (2007), Department of Natural Resources (DNR, 2007), and National Wetland Inventory (FWS, 2007) maps to assess the nature and relative extent of wetlands and streams mapped on and in the vicinity of the site. We also reviewed the Streamnet (2007) database to assess the potential for salmonids to be present on or near the site. After we arrived at the site, we traversed the site to observe the physiography (e.g., depressions and ditches) and plant community arrangement of the site. We also observed the area within 150 feet of the site to look for the presence of critical areas. We used the Routine On-site Determination method detailed in the U.S. Army Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory, 1987) and Washington State Wetlands Identification and Delineation Manual (Ecology, 1997). We identified plant species using the Flora of the Pacific Northwest (Hitchcock and Cronquist, 1973) and A Field Guide to the Common Wetland Plants of Western Washington and Northwestern Oregon (Cooke, 1997). The associated indicator status for each plant species was determined using the National List of Plant Species That Occur in Wetlands: Northwest [Region 91 (Reed, 1988 updated in 1993). We assessed wetlands using the Washinton State Wetland Rating System for Western Washington - Revised (Hruby, 2004). We measured the width and depth of the stream with a steel tape. There is no published method for assessing streams. We referenced City of Renton (Renton, 2005a) regulations to assess applicable critical areas and permitting requirements. Soils were identified using the Soil Survey of King County Area. Washington (Snyder et al., 1973). We marked the location of sampling points with flagging with indelible ink. ESM Consulting Engineers located the flags and Brick Tudor Studios created the maps. Wetland determination rating forms follow. Indicator categories shown on the field data forms are defined as follows: OBL (obligate) FACW (facultative wetland) FAC (facultative) FACU (facultative upland) UPL (upland) NI >99% 67%-99% 34% -66% 1% -33% <1% No Indicator Assi ned A positive or negative sign more specifically defines the regional frequency of occurrence for FACW, FAC, or FACU species. A positive sign (+) indicates a frequency toward the higher end of the category. Conversely, a negative sign(-) indicates a frequency toward the lower end of the category. C:/ESM/Rose/WeHand Delineation Report.doc Chad Armour, LLC 02126/07 Wetland Rating Field Data Forms DATA FORM l(Revised) Routine Wetland Determination orns et an e neation anu (WA State Wetland Delineation Manual or 1987C W I dD Ii M al) ! Project/Site: }(.o'.>e.L,Jooil #•1411..1..,....J.s. Applicant/owner: /l "'1 £-(t" ..._"' (!,J "-!>'.>,,e., Jk, ~ Investi~ator(s): Cl., 4 At r ...... o .. ,/. LU- Do Nonna! Circumstances exist on the site? (rs) no Is the site significantly disturbed (atypical situation)" yes ~. Is the area a potential Problem Area? yes no Explanation of atvnical or oroblem area: VEGETATION (For strata, indicate T = tree; S = shrub: H = herb; V = vine) Dominant Plant Soecies Stratum % cover Indicator Dominant Plant Soecies 0,.e.lc1··~ ,11(/1., ... ,A_ ft 60 rkw -::s I.A.. ">..U-S.. ~ ,a.~ ,+ bO r!kv.J R lA.,, 't, v..::, .£i S<..clo' s 10 -ntc'.-U.. 1.1 -,l1a_tfi~ r,,..l1L• ... ~ < r=A c'.-1-l.. • I, HYDROPHYTIC VEGETATION INDICATORS: % of dominants OBL, FACW, & FAC /DO Check all indicators that apply & explain below: Date: 1/2 LJ7 County~ /~~ State: IV Sff/R: Community JD: Transect JD: Plot ID: :::, p-I Stratum % cover Visual observation of plant species growing in Physiological/reproductive adaptations areas of prolonged inundation/saturation --Wetland plant database Morphological adaptations --Personal knowledge of regional plant communities Technical Literature Other (explain) Hydrophytic vegetation present? ~ no Rationale for decision/Remarks: HYDROLOGY Indicator =z -- Is it the growing season? yes G Water Marks: /"yes ) no Sediment Deposits~ no -on Based on: / soil temp (record teA ) Drift Lines: yes e1) Drainage Patterns: ~ no J other (exnlain) . <!l_ -f,:.. Dept. of inundation: _f!j]Jmches Oxidized Root (live roots) Local Soil Survey: ye~ !), ~inches Channels <12 in. ves no Depth to free water in pit: FAC Neutral: yes no Water-stained Leaves yes® Depth to saturated soil: inches Check all that apply & explain below: Other (explain): r~...-Si:>1"1..._J k ~ cw/ ....£-5 ~ Stream, Lake or gage data: --I <) f 'j-i..Q, ("-e <:_ IO V\ Aerial ohoto=ohs: ~ Other: · Wetland hydrology present? yes @) --t I o-f 2 s-.. >) Rationale for decision/Remarks: . h k. f, ,1.,s d..,,.e.,,. ""f.,!'.'.,.-e"' :.5 ( ~/{)ti-St>o sf) J.(~'-~ ,f. ~ ...,_ ).oo"''""..S• -~-;( ;.J-1.,,t....,J,.4..J I-YA J..<L,,,.=e '°-r ..,,....,. ... -..... -£.. I -, I SOILS ~P-\ Ma~ Unit Name ft}.ie(w,,~.O.. z:t•->J.tJ..llj ~· .. .Ry /o-.J (Senes & Phase) ~ -fol~ p~u .... 'f ~"f..s Drainage Class /110{1, w~JI ...,.J_.,..,,..,..J. Field observations confirm @ No . Taxonom (sub rou \· E>'l •£-bt.vi, .... 1.. '<L fa d Profile Description Depth Horizon Matrix color . Mottle colors Mottle abundance Texture, concretions, Drawing of soil · (inches) (Munsell (Munsell size & contrast structure, etc. profile moist) moist) (match descri11tion) ~ -"~1 $«."'-Jl.'f vJ e.f---,,,,~J L ,, ~ t,II../ ID I (f,11) ' Hydric Soil Indicators: (check all that apply) ti/A --Histosol --Matrix chroma $ 2 with monies __ Histic Epipedon __ Mg or Fe Concretions --Sulfidic Odor __ High Organic Content in Surface Layer of Sandy Soils __ Aguie Moisture Regime __ Organic Streaking in Sandy Soils __ Reducing Conditions __ Listed on National/Local Hydric Soils List Gleyed or Low-Chroma (-1 l matrix Other ( exnlain in remarks) Hydric soils presen_t? yes ~ ~ :h ft, b.r ~ -r-"t""-s fve....,.,.. Rationale for decision/Remarks: \, ~ , .f eo .--r, .J · I... 01..-i"' Z-D~,1)1 w,.,/e ,~ .fill, (-ii\ r..d"'-f., _ 't'o "?..f~ 1-'~'~"'4:: /i-., C. • A _:)!:.i.-t:, -Wt 1,f ~<'AucJ J-~~&~d <(.1',k..L$k"'-b~8 ,k.el-1 /~..,,,., .. ~ Q... .c.,J-r "'l'.-c.-,.,l..,.:.-1. is vio fo..._-t,ef J?r,e.s,::...., WetlanA Determination (circle) V Hydrophytic vegetation present? &)~ Gd Hydric soils present? yes no ls the sampling point yes Wetland hvdroloav oresent? ves no within a wetland? Rationale/Remarks: Ar,fu...._) 1,p l ' (.f, 1\) ,.J...__+-..,~ 1Z> ...._ (!iJ .,r. ' 5,et,.:)el' I, ... e.. , bdl~ ke,rt?. J NOTES: 6fv1:::"""'-~ -to 1t..i.A ,,._,_()t.,..)~ (ve.o,...; ~ 0,.!1t"d1!) eo,rr,cb,,r £rrr~.,__ fib~ 0~ ~1'£.!!pf~~) -tD ~ ~v,.tL,, t\.,-.}, r.L.._) rJ • .,--z:; CD~-.,_~, +1 {DCJTJ 1"' dt"' ~,n-,f,£1~1 $.:,,), Revised 4/97 DATA FORM 1 (Revised) Routine Wetland Determination (WA State Wetland Delineation Manual or 1987 Corns Wetland Delineation Manual) ! Project/Site: Applicant/owner: ,A,... .. ,,~ .. 4"-J$"-fl.,..,,.._,:. Investie:ator(s): e,,"1,,c ,.b IJ ,....._., .. / L~ Do Nonna! Circumstances exist oh the site? Is the site significantly disturbed (atypical situation)? Is the area a potential Problem Area? Explanation of atvnical or problem area: ~ yes yes no ~ VEGETATION (For strata, indicate T = tree; S = shrub; H = herb; V = vine) Dominant Plant Soecies Stratum % cover Indicator Dominant Plant Species kn - I HYDROPHYTIC VEGETATION INDICATORS: % of dominants OBL, FACW, & FAC 00,h) Check all indicators that apply & explain below: fJ1:, '1 e, Date: I /~2/07 County: /<G , ~ State: w Pr S/T/R: Community ID: Transect ID: Plot ID: .t,P-2- Stratum o/o cover Visual observation of plant species growing in areas of prolonged inundation/saturation Morphological adaptations Physiological/reproductive adaptations Wetland plant database Technical Literature Hydrophytic vegetation present? Rationale for decision/Remarks: HYDROLOGY yes ~ Personal knowledge of regional plant communities Other (exolain) Indicator Is it the growing season? yes e Water Marks: yes ®,. Sediment Deposits: yes~ on Based on: ~--,.<-soil temp (record temp . ) J other (exolain) ,II &.f e, Dept. of inundation: E.LD inches Depth to free water in pit: A inches Depth to saturated soil: .:iJ3_ inches Check all that apply & explain below: Stream, Lake or gage data: __ Aerial photo~raohs: Other: Wetland hydrology present? yes Rationale for decision/Remarks: -r;; f :,,,, f ( ~ '1 IY)1 1111 Drift Lines: yes ~ Drainage Patterns: ye@ Oxidized Root (live roots) Local Soil Survey: yes~ Channels <12 in. yes (no) FAC Neutral: yes no Water-stained Leaves ye(:0 Other (explain): t"~<'S""'"'l k..:lo..::ilc..l:5c. ~-f / -n..e "-efi'""'. SOILS Map Unit Name (Series & Phase) s p_;,._ AJk.,.,@ll ~~Ji 5-. .. ;1 1""""; 6 iD1S'p=e t' ~P<l¥> Drainage Class f(,,,IJ, v,Jd/-~.,,_,~,J Field observations confinn · ~ No "'+,.,_ j)..,_,..t;> ts ma ed e? Profile Description Depth Horizon Matrix color Mottle colors Mottle abundance Texture, concretions, Drawing of soil (inches) (Munsell (Munsell size & contrast structure, etc. profile moist) moist) (match descri11tion) 2, A lb '< R.. 2.,J z.,. :Jr&.:JJ /06.. .... i. s.... ('.i.....)o, I) we.-+- -~ ->/f!.r'J ~d-6'.i :, r.-,.,e,) f,H ....) . . Hydric Soil Indicators: ( check all that apply) tJ [)Yl e. Histosol __ Matrix chroma 5 2 with mottles --__ Histic Epipedon __ Mg or Fe Concretions ___ Sulfidic Odor __ High Organic Content in Surface Layer of Sandy Soils __ Aguie Moisture Regime __ Organic Streaking in Sandy Soils __ Reducing Conditions __ Listed on National/Local Hydric Soils List Gleyed or Low-Chroma (=I) matrix Other (exolain in remarks) Hydric soils present? yes ~ Rationale for decision/Remarks: Wetland Determination (circle) Hydrophytic vegetation present? yes~ G) Hydric soils present? yes no Is the sampling point yes Wetland bvdrolovv nresent? ves o within a wetland? RationalPIRemarks: - ~ /of;!.. 3 ""/o A ~~""-r eA.6ot:' NOTES= ~ ........ pi~ P"'"'"i:;; ,.,. -. .. w ~ , .... ..,.,... "lee..,,. ..._ -1z, f"o""'f ~ '""'-' ",,..,.,_J:.. +v,.:, ,1./ L -rk ~P"it,. ... , C,IP!.~ !7 ~-J .3 ,.,.,i:s _ (e:5 ~t6-1To"'-f-r, ..... -.,~:::,, 0 V\ 1'1---<-~j"' UI,>~ L., II 11~-e.) .>i $"J,.p~. $/1> r &-(>4-rel1 4,ve,~ l,<)1it .ot 11.,,L,4. ~--:5,)-t{ ~-f /f1i,..4 /.fi#"'-b}~Kb-err1; OCC."-S1>D"'..J.. b)~k_ a;,fr,,1-1 WPD Jl, tr ~e fiz N.;. ZI;)" .lbh) Revised 4/97 MAR 1 6 2007 RECEIVED UNION PROPERTY Preliminary Technical Information Report March 8. 2007 Prepared for American Classic Homes 2806 Sunset Blvd. Suite E Renton. WA 98056 Submitted by ESM Consulting Engineers. LLC 20021 120" Avenue NE Suite 103 Bothell. WA 98011-8248 425.415.6144 tel 425 415.0924 fax www.esmcivil.com ~ i Prepared by, Emily Neuhaus Reviewed by: Steve Schuller. P.E. UNION PROPERTY Preliminary Technical lnfonnation Report Prepared for American Classic Homes 2806 Sunset Blvd. Suite E Renton. WA 98056 Submitted by ESM Consulting Engineers. LLC 20021 120"' Avenue NE Suite 103 Bothell. WA 98011 Job No: 1352-001-006 EXPIRES 04/02/l)'/l'I +- i 1 PROJECT OVERVIEW.. .. ...... ... . .... 1 Project:.......... .. .. .. .. .. .. . . . . .. .. ... ... ... ... .. 1 Site Location: .. .. ... . . .. . 1 Adjacent Development: . 1 Existing Conditions:.............. .. . .. .. . .. .... . . .. ......... 1 Soils: ... . ............................... 2 Figure 1 -TIR Worksheet . .. . . . ............................. 3 Figure 2-Vicinity Map. ... .. ... . . . .............. 7 Figure 3 -Existing Conditions Map.. . .. 8 Figure 4 -Offsite Basins Map. . . . . .. .. . ..... . ... . . . . . . 9 Figure 5 -Soils Map. . . .. . . . . . .. . . . . . ..... . . ..... ... . ........ 10 Developed Conditions:... .. . . . .. .. .. . .. .. .. . . .. . . 11 Design Standards:. .. . . .. . .. . . . . .. . . .... .. . .. ... .. . . . . .. .. . . 11 Figure 6 -Developed Conditions Map . . .. .. .. . . . . .... .. . .. .. . .. . . . . 12 2 CONDITIONS AND REQUIREMENTS SUMMARY ................................. 13 King County Smface Water Design Manual Core Requirements: ............................. 13 King County Smface Water Design Manual Special Requirements: .................... 14 3 OFFSITEANALYSIS. ............. . ............................ 15 Figure 7 -Downstream Analysis . . ..... 18 Table 1-Offsite Analysis Drainage System Table... . .. .. . . ......................... 19 4. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN .. ..... .. .. . . 20 Existing Hydrology:... . .. . . .. . ... ... .......... . .................. 20 Precipitation: ..... .. . ... .. .. ... . ... 20 Figure 8 -Topographic Map .... . ............ 22 Figure 9 -Existing Hydrology Map.. . .......... 23 Developed Hydrology:. . .. ..... . 24 Figure 10 -Developed Hydrology Map . . .. 25 Flow Control System: .. . ....... 26 Water Quality System: ..... 31 5. CONVEYANCE SYS IEM ANALYSIS AND DESIGN.... . ... 33 6. SPECIAL REPORTS AND SilJDIES .... ... ... ... . 34 7. OTHER PERMITS ... . .. . .. ... . . .. .. ... ..... .. ... . . . . . . . ... .. . .. . 35 8 ESC ANALYSIS AND DESIGN . .. . .... ... .. . ........................ 36 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT. ..... 37 10. OPERATIONS AND MAINTENANCE MANUAL .. ...... . ........................... 38 APPENDICES: APPENDIX A -Reports APPRENDIX B -Downstream Analysis Information APPENDIX C -Runoff Control and Water Quality Calculations ESM JOB# 1352--001-006 1. PROJECT OVERVIEW Project: Union Property The proposed project is the development ot a 3 96-acxe site into 27 single-family lots, recreation space, and a detention vault In addition, frontage impxovements axe proposed along No1theast 2•d Place. The pmject is called: Union P10pe1ty ESM Job numbe1: 1352-001-006 Site Location: The p10posed pr~ject site is located at 230 Union Avenue No1theast in the City of Renton, Washington. More generally, the site is located within the NW 1/4 of Section 15, Township 23 North, and Range 5 East of the Willamette Me1idian. The site consists of five parcels A, B, C, D, and E v.~th King County Parcel Identification Numbeis of 5182100068, 5182100069, 5182100073, 5182100079, and 5182100081, tespectively (See Figwe 2 -Vicinity Map). Adjacent Development: Development adjacent to the site includes the following: No1th-Single-family homes and an undeveloped giavel lot · West-Union Avenue Northeast ·· South-Single-family homes East -Single-faxnily homes Existing Conditions: The pmject site is comprised of five prucels totaling 3.96-acxes. Parcels 5182100069, 5182100073, and 5182100079 contain three single-family homes with detached garnges. Paxcels 5182100068 and 5128100081 are undeveloped and contain pastu1e with some forested axeas with light unde1brush (See Figure 3 -Existing Conditions Map) I opogtaphy for the site slopes from west to east with a steep slope along the nmtheastem comer of the site. Maplewood C1eek 1uns southe1ly along the eastern boundruy of the site. Stmmwater runoff fiom the site sheet flows easterly with slopes 1anging from 3% in the west to 23% in the east St01mwate1 runoff either sheet flows into a Class III wetland along the nmtheastem comer of the site and then into Maplewood C1eek, 01 sheet flows directly into Maplewood Creek In addition to the site, frontage improvements rue proposed along Nmtheast 2nd Place that is directly south of the site. This road is currently an asphalt road of width vruying from -I - ESM JOB# 1352-001-006 Union Property 10 -17 feet. Access to the road is off Union Avenue and it slopes eastet!y at 5% Stormwater runoff from the road sheet flows easterly towards Maplewood Creek. Offsite flows contributing to the site are fiom two locations. The first location is the undeveloped parcel north of the site, up to and including half of Northeast 4th Street (Basin A). The other location is the single-family lot northwesterly of the site, up to but not including half of Union Avenue Northeast (Basin B) (See Figure 4 -Offsite Basins Map) Soils: Per the Natural Resources Conservation Service (NRCS), onsite soils ate Alderwood Gravelly Sandy Loam, 6 to 15 percent slopes (AgC) (See Figure 5-Soils Map) -2 - King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Project Owner American Classic Homes. LLC. Address P.O. Box 1830 Renton. WA 98055 Phone Project Engineer Steve Schuller. P.E. Company ESM Consulting Engineers. LLC Address/Phone 20021 120"' Ave. NE #103 425-415-6144 ~ Subdivison D Short Subdivision D Grading D Commercial 0 Other ________ _ Community Newcastle Drainage Basin Lower Cedar River Project Name Union Property Location Township 23 North Range 5 East t-N'J Quarter of Section 15 o DFW HPA o Shoreline Management '.l COE 404 !Rockery D DOE Dam Safety Structural Vaults D FEMA Floodplain other 0 COE Wetlands D River J5{ Stream Maplewood Creek D Critical Stream Reach D Depressions/Swales D Lake __________ _ D Steep Slopes Soil Type AqC Slopes 6-15% D Additional Sheets Attached D D D D D D REFERENCE D Additional Sheets Attached D Floodplain--------- ~ Wetlands 0.43-acres D Seeps/Springs D High Groundwater Table D Groundwater Recharge D Other _________ _ Erosion Potential Moderate Erosive Velcotles Slow to medium LIMITATION/SITE CONSTRAINT None known MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION ~ Sedimentation Facilities ~· Stabilized Construction Entrance ~ Perimeter Runoff Control ~ Clearing and Graing Restrictions ~ Cover Practices ~ Construction Sequence D Other D Grass Lined D Channel ~ Tank Vault I):. Stabilize Exposed Surface g, Remove and Restore Temporary ESC Facilities I>( Clean and Remove All Silt and Debris 'g Ensure Operation of Permanent Facilities .El Flag Limits of SAO and open space preservation areas D Other D Infiltration Method of Analysis D Depression 2005 KCRTS D Pipe System D Energy Dissapator D Flow Dispersal Compensation/Mitigati on of Eliminated Site LJ Open Channel 0 Wetland D Waiver Storage D Dry Pond D Stream 0 Regional NIA D Wet Pond Detention Brief Description of System Operation Stormwater runoff is collected via a closed pipe system to a detention facility located in the southeast corner of the site. Facility Related Site Limitations Reference Facility Limitation N/A Cast in Place Vault D Drainage Easement )'& Retaining Wall D Access Easement D Rockery > 4' High D Native Growth Protection Easement D Structural on Steep Slope 1 Tract D Other Other : !-- I or a civil engineer under my supervision have visited the site Actual site condrtions as observed were incorporated into this worksheet and the attachments To the best of my knowledge the information provided here is accurate w w z z w w w ~ ~ z ;3 w ~ '1 z ~ !: "' ::l l; 0 NOT TO SCALE VICINITY MAP PROJECT: UNION PROPERlY SCALE: JOB NO. DRAWING NAME 1352-001-006 DATE : EN-01 DRAWN 1#=1§• CONSULT IN (l ENGINE E R S LL c 1fT14 ...., er-""""'•Y "-I G I <f> I ~ I Sdte 101 Bothel. WA 980n www.esmcivil.com Civil Engineering Public Work$ Land Surveying Pro,j-ec.t Mom,9emenl [{C{R.>.l 'liil.T l"'l l!.33-flT.) SOTllEll U5 "4",S-iilH ClC EL\Jt,I ~) 674-190!, Lend Plonnin9 Londscope A:-chilecli,m:t NT S. 02/14/07 ECN VICINITY MAP FIGURE 2 n 0 SITE BOUN TREES I ~--. MAPLEWOOD CREEK, I : -~"---'-~- \ > -.. _:::,_:::::,.:.-._,~ .\,6' ' / -"~'· ~ \ Ji / / . \\~\\''"/ r""' ;\, t;,'#ct,~ I " "'~"' / I • ~) \I ~ ~~, ·-'\<?~"c I fl ',, ,.J/1 \ ---._:;-,,,---®l!i-< ~ \'©./ J. /<I I /I > ) " \ I ~--"' ((~ ,//.f.f .. . -· ' --~/._ * ( ...... :>;,/' l _c.J -1· &~P;n1·-~-1 ,' I I I \ ·--. __ _11!1~--r ~/ ' G . I' -• I \ I I '. --\. , · !-y c1 · ' • , 0 T • / "'-_l,·.1Qf I 171 L~~ .. J ---f-', (i'i:)J.. I I \ ., \ '\\ I r.,,f'<""· · ld . ' g• "-\?,.~ I I ' ,,,, · I ' 1r' I ''\' ·-·-~-----·-···----\--..... ol OUTBUILOIN1, -~' ,,/:'_ .,,1 1 ) r;-1 1 / ./ .... 1 \ :i \ --·, ~-I' · I · · .,. -··""·":-. r',~~·J I f PASTURE . . ,I I\ ! _. ,...1,0"' r / • · GRASS y ' ' -' -·~ ~ /J / , ., ES ~ r , i ! 1 \ I I' /lil <' i II ~ j, ,\lll ~ 1 ,•• > /-I ) \ I rl /"' 'Y / . !('·' ,,J .. t,.l ,/ __ j I ,;; p.. ("(·-1"{.. /~!/;#" ,_ -n , ,aRp;TEo • c,f\-, _/_ . __. 11 i ~t-nl . ~-I / ~4-·~ -~# 41~ [~. ;,/ / >-".':.J \ I \ ' ' ,..-'· --/ I ·; '· . / "''. ,-t.~ / / I \ '"-~ .·-.. ,w __ .,,. /' _/( / \ < JG G ,-·.··,: / -·---/ ,;_ \ I 1' . I\ \ . ) " ,/. .· ·,' '' . _, @ \ j\ I[ ··-'._ ri'/l , •• C •. , ,;,,: -· / --...,_ l"'' . ·1 '·@ ___!_ -:LL 'ti., w "<:"' • 111 ~. -- \I scALE= 1" = so I fr .~:--0 ,o Jo I : a. < i I ~ (/) z 0 Q. "' ;:::: 0 "' 0 cc "' z Q. 5 0 (.) z r.: (!) 0 z ~ z ::, x w ol,;: \!! ; ::: f."I ~t.; i * m ,! • -'l h !\! 11, ii !I! t ! ' ~-~I] ! I! iii • ,.. Jl fid - I ij!, m r l 11 f 1 :11 I ' L I ! )· www.esmc,viJ.ccm ~t:,-:::""~ I ..,,_ ,,.,_..,_ OFFSITE BASINS MAP UNION PROPERTY FIGURE 4 • 0 0 ------,-,, _______ . -.... ----, (/) 0 )> r m ~ ' I\) 0 0 I rr ;, u +· • 0 " 0 .. 0 ~ 0 s: f !I-~ [,! §1! i& ~r !< g,!""' ~-~ ~ 0 0, 0 ~ 8 " 8 ~ 0 8;:i 11/. I=@¢• CONSULTING ENGJNEE:RS LLC 11714 ""'1h C,-HI< Parl<way N. I $ I ~ I ~ I Sult0101 Bothel,. WA 9SOf1 www esmcivil..com f1:DEIW. Wf;Y l'~I .BJa-li\lJ, BOTii[ll ~2:'> '15-61~~ CU (LUU ~D9 &74-1~ Clvil E,,9in.,,e~i.-.9 Publl<: Worlcs Lond Surveying Project Uonoge:ment Lond Plon:"ling Londscope Archileclure SOILS MAP FIGURE 5 ~ ,I! C: !! "' l 0 c- i C: !i. z e 0 ;,,- ~ s ; - "' ~ a 0 H, ;,,- 0 - I ~ I \ ESM IOB/11352-001-006 Union Property Developed Conditions: From the 3.96-acres, 0 .17-acres are ptoposed to be dedicated as 1ight-of-way to No1theast 2"d Place and O 43-acres ruea to a Sensitive Alea Tract The remaining 3 .. 36-acres rue proposed to be developed with 27 single-family homes, apprnximately 510 lineal feet of public roadway, 374 lineal feet of alleyway, 205 lineru feet ofjoint use d1iveway, and a detention vault (See Figure 6 -Developed Conditions Map). The public roadway is prnposed to consist of a 42-foot right-of-way section with 5-foot walks on both sides of the 10ad, ve1tical curb, and 32-feet of c10wncd asphalt roadway. The allies rue pmposed to consist of a 26-foot wide tract with a 5-foot walk on one side of the alley, vertical curb, and 20-feet of asphalt rnadway (sloped to one side).. The joint use d1iveways rue proposed to consist of a 20-foot v,ide easement wHh 18-feet of asphalt driveway (sloped to one side}. For ptelimina.ty design pmposes, sto1mwater rnnoff from the entire site {roads, landscaped areas, and buildings) rue p10posed to be collected and conveyed via a closed pipe system to the detention/wate1 quality facility in the southeastern section of the site. However for final enginee1ing design, some of the roof downspouts may be 1eleased to sheet flow directly into the Class III Wetland in the no1theastem come1 of the site (bypassing the detention facility) to maintain mnoff flows to the existing wetland.. The detention facility will release stormwatet runoff to the sensitive ruea tract whete it will sheet flow to Maplewood Creek. Proposed frontage improvements along Northeast 2nd Place consist of constrncting tht ee- quruter street imp1ovements for approximately 510 linear feet The thtee-quruter street imp10vement consists of a 26-foot 1ight-of-way with a 5-foot walk, ve1tical curb, and 20- feet of c1owned asphalt roadway. This stormwater runoff from the roadway is proposed to be collected via a closed pipe conveyance system that ties into the sites collection system and is sent to the detention/wate1 quality facility. Offsite flows from Basin A rue proposed to tiavel th.tough the sensitive ruea trnct (Class III Wetland) along the nmtheastem po1tion of the site as it does in existing conditions. Offsite flows from Basin B rue proposed to be collected along the edge of the site and conveyed around the development to be released via sheet flow to the Class III Wetland in the no1theastem corner of the site. Design Standards: The p1oject is to be designed in accmdance with the 2005 King County Surface Water Design Manual (2005 KCSWDM) and the 1993 King County Road Standruds (1993 KCRTS) as amended by the City of Renton. -11 - ' I ~ i i~ /i / I \j ·-- ') I \...__ \ ', ---, '--·---40a ···---, IRi\CI A r::-__ -_ ·: 5 , . ··-·;ol .. CT lC ..... ____ r,·:··-•- . ' ---'. :· --. -~ ~---:_:~,l!I'...-:"'. ~ . J , , -· , , ' '. ~·.. . : ---.:. ,_.,..3, 'I: ' , ~ . , , . 4 . 1 'l r l , ~-i -''\J ·',.J SITE BOUNDARY\ 18 17 19 -·---.....l I /f / SCALE: 1" = 50 r-1 M I --50 25 0 ,o 100 , 29< '~ ' ( : ,- ''-:.,.,, 21 ,. MAPLEWOOO CREE\ I I I I 23 0 'r\\ ,"'-k I ij . \ ') : i \ I l • < -r 2+1 \ \ \ I ) I ii ~-L---.L ___ --1_)___ _ ___ j / ,/~/ J I ~- /. _ ,_ -_ .... ··'-_ - 1 -1/ II .:,, < ··--~ 4-: ,_/ . .-:/~ ~" --~ I -( r (s , :/ 11 I I I f ' ·· ' , ~ \-·~I-/, I ' __ ,_:""'-i· rr:-:--11 11 \~ --.-. " I ' . I \ \~6ll : ( !/ I , l . \ ' I / , .\ ·, ' . I ) .. I~'-/I -,~,_ i.J \ ,r </1 I .. ti; ' . J : ,i I . : Q 1_~, -( ti 0 . _, ,.-", ,/ \. \~i IG ,.. --,....-.,.,,..-_.,..,. \ "" I I',/ '/' ' " ~ / ,. TF \ V 1•6: 1 ;-fHAC <(E Id(~ STORM VAULT / I a: z I r \~~:;:1-·~1: 1-~:f'.-:-:._:_ • 13 >i/ I ' , , I' ! : / 14 : : /: ' . f . r. :_. ___ ; '/ ·------.·--·r·- / ' 11 : ,--·-- ,,./ : 10 · . -:--· <( ! ;_...-·----.. -- :-=-:-: ·:-:---:·~ ~ r ~ \ ( ,..~ 1 1 N \_.. ~ \..__ l f : cj,:j· ·/ _12./_ ----) ---1 l -----'-, L_ ·e-c~---;---· .... ::-r:"'~ ... L_ . -I $ , -. • t 8 0 ( /~-l 'j' ( . '-----' :.::~----'----"""' \ ' I -, ---·--,, .: ,,- $ ~ . t.____ -'----.............. ~ . . .. \\ /i _,,'"'._'1,' l Vi ', ' ' , ...... \ \ n " a. <( :a i'.:: Cf) z a: 0 w f'.= a.. "' 15 0 .., z a: ~ 0 0 a.. "' Cl z i;: w 0 a. g z w :::> > w Cl -~]D ~ "~ 'li ' :. iii rl a:_ l ii ! ! Ill 1! " . - ii 111! -l ! I I I! ,.. it o 1 Ul - I [jl, I ! ii ii ,Ii I ,. ' - ' ; r I ESM JOB# 1352-001--006 Union Property 2. CONDITIONS AND REQUIREMENTS SUMMARY King County Surface Water Design Manual Core Requirements: 1. Discharge at the Natural Location Stormwater runoff is prnposed to be released at the natural discharge location to the extent possible. As in the existing condition, stmmwater 1unoff is to be releases to the sensitive aiea tract along the eastern side of the site 2 Offiite Analysis· An offsite analysis was performed by ESM Consulting Engineers LLC. Please see Section 3 of this report 3. Flow Control The site is located in a Conservation FC Areas flow control area. Please see Section 4 of this repo1t. 4. Corrveyance System Ihe sto1mwate1 conveyance system is to collect stormwater rnnoff from the site and convey it, via a closed pipe system, to the detention / water quality facility .. Contributing offsite rnnoff flows is to be collected and conveyed atound the site, via a closed pipe system, that bypasses the detention I water quality facility Please see Section 5 of this report 5 Erosion and Sediment Control Ewsion attd Sediment Controls (ESC's} are to be provided for the site. A Temporaty Erosion and Sediment Control Plan (T .E.S.C Plan) will be created and will be found in the engineering plan set. Please see Section 8 of this repOit. 6 Maintenance and Operations The Maintenance and Operation Manual for the stormwater system will be included in Section 10 of this rcpmt. 7. Financial Guarantees and Liability Ihe Bond Quantities Worksheet will be included in Section 9 of this repo1t. 8 Water Quality. Per the King County Water Quality Map, the site is in the Basic Water Quality tteatrnent ai·ea Wate1 quality is to be provided via permanent storage in the detention facility Please see Section 4 of this report -13 - L ESM JOB# 1352-1JOl-006 Union Property King County Surface Water Design Manual Special Requirements: I Other Adopted Area-Specific Requirements The prnposed project is not known to be located in a Ciitical D1ainage A.I'ea (CDA), a Maste1 D1ainage Plan CMDP), a Basin Plan (BP), a Salmon Conseivation Plan (SCP), a Stormwate1 Compliance Plan (SWCP), a Lake Management Plan (LMP), a Flood Hazard Reduction Plan (FHRP), nor a Shared Facility Drainage Plan (SFDP) area. 2. Flood Hazard Area Delineation The p10posed ptoject is not known to be located within the 100-year floodplain or withln a floodway aiea_ 1n addition, the prnposed site is not located adjacent to a lake, nor a closed dept ession 3 Flood Protection Facilities The p10posed p10ject does not contain nor is adjacent to a levee and / or tevetments. 4. Source Control The p10ject is a residential subdivision and is not subjected to this tequirement 5 Oil Control. The project is not a high-use site development, does not propose $100,000 or mote to an existing high-use site, and is not subjected to this requirement. -14 - ESM JOB# 1352-001-006 Union Property 3. OFFSITE ANALYSIS ESM Consulting Engineen; pe1fo1med a Level l downstream analysis fo1 the proposed Plat of Union The downstleam drainage system was reviewed for one-quarter mile downstream ofthe site. The following five tasks (outlined in the KCSWDM) weie completed in an effott to identify any negative downstteam impacts to the existing drninage system Task Number 1. Study Area Definition and Maps The project is located within the Lower Cedar River drainage basin. The d!ainage study area is approximately a one-quarter mile long path encompassing the site's downsti·eam conidor See f7 -Topographic Map for an ove1view of the basin study a,ea Task Number 2. Resource Review The following resowces have been 1eviewed m conjunction with the downsti·eam analysis for the Union Property plat: Adopted basin plans • The site is located in the Lower Cedar Rivei dJ:ainage basin and the Cedar· Rive, / Lake Washington watershed Sensitive Aleas Folio • All sensitive areas identified by King CoUIIty iMap me included in Appendix B • WetlaIIds -A wetlaIIds report was prepared by Chad Armow, LLC aIId is included in Appendix A. The 043-acre wetlaIId is located on the eastein section of the property and is preliminarily rated a Class Ill. • Streams and 100-Yem Floodplains -None mapped • Eiosion Hazaid AI·eas -None mapped. • Landslide Hazaid Areas -None mapped • Seismic Hazard A.r·eas -None mapped • Coal Mine Hazaid Areas -None mapped. Drainage Complaints • The closest d!ainage complaint was less than a quarter mile downstreain; however, the Union Property subdivision will not aggravate the site fo1 the reason that the propeity lies on the opposite side of the Maplewood Creek bank. U.S Depaitment of Agricultwe, King County Soils Swvey • The soils of the project site we1e obtained from the National Resowces Conservation Society (See Figure 5) -15 - ESM JOB# 1352-001-006 Union Propertv Flow Control Applications Map • The proposed site is located within a Consetvation FC Area flow control. Water Quality Applications Map • The site is located in a basic water quality treatment area per the King County DDES_ Task No. 3. Field Inspection A site 1econnaissance was pe1fo1med on February 2, 2007, for the pwpose of analyzing the proposed prnject site and its upstream and downstream couidors.. The weather conditions we1e diy, 50 degrees Fahrenheit and cloudy. The field inspection documented in this report will have all descriptions and referenced labels coincide with Figure 7 - Downstr·eam Analysis and I able 1 -Off site Analysis Drainage System Table Sto1mwater from the site sheet flows to the eastern section of the property and is collected by the enhanced Maplewood Creek. At the time of the downstream analysis there was no wate1 obseived in the creek immediately east of the ptoject site. Maplewood Creek has the appearance of having a man-made cut which can better serve stormwater conveyance of!arge upstream flows Maplewood Creek proceeds to flow in a southein direction serving as a collector for various developments along the conveyance path (Label A). Throughout the downstream analysis, Maplewood Creek did not have any indications of erosion or scour. About an eighth of a oiile downstream from the site, the c1eek mains to a large open ar·ea where dtainage dispe1ses (Label B) Within the open area, groundwater was observed seeping from the ground and filling the cTeek with the first signs of a downstream analysis flow. After the large open area, drninage again converges into Maplewood Creek and is directed towards a 12-inch culvert before Breme1ton Place Northeast (Label C).. The culve,t had no sediment and connects into a large 48-inch catch basin, which serves as overflow protection for flows too large for the 12-inch culvert The catch basin had what appeared to be a 36-inch culvert conveying flows underneath Biemerton Place Northeast (Label D). Across the street, the culvert has an outfall into a deep draw with large rocks lining the channel (Label E).. This completed the quarter mile downstream analysis. Task No. 4. Drainage System Description and Problem Descriptions The cuuent dtainage system appeared to be adequate to convey the largest stmmwater events The lar·ge culve,t at Bremerton Place No,theast appeared to be an improvement to addiess any past drainage problems that may have arisen. The drainage system appeared to be in good shape with no visible signs, which would indicate any type of conveyance problem .. Task No. 5. Mitigation of Existing or Potential Problems The Union Property is located within a Basic Flow Control Area as identified by King County iMap. The Union Prope1 ty plat will not aggravate any existing downstream problems by detaining sto1mwater rnnoff at a Level 1 standard. This standard matches -16 - i L ESM JOB# 1352-001-006 Union Property the developed land mnoff to the existing site conditions 2-year and 10-year peak storm events. Stormwater will be collected and the flow will be restricted through orifices sized to meet the Level 1 criteria -17 - I :... I www.esmc1vil.com ~:;:,1c~::""'l 1 JOI -·-------- DOWNSTREAM ANALYSIS MAP UNION PROPERTY FIGURE 7 .... ---,----·. en 0 0 )> r m ~ ' N 0 0 l\l 0 0 • 0 0 Basin: A I Mapiewood Creek I B [ Open dispers10n area 12" Culvert I C I 48" Catch Basin D 36" Culvert E Rock lined outfall TABLE 1 -OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE SURFACE WATER DESIGN MANUAL, CORE REQUJREMENT #2 Subbasin Name: Site discharge 3 0 None None 5 600 None None Is I 900 I None I Noue 5 1280 None None 5 1320 None None Subbasin Number: appeared to have man-made cut. Groundwater seepmg from ground. -r-·-··----·· ···. -·r·-----v--·-···---· ESM JOB# 1352-001-006 Union Property 4. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Existing Hydrology: Vegetation cove1 on the site is split up mainly between the eastern and western sections (See Figwe 9 -Existing Hydrnlogy Map).. In the western section, thete aie thtee single- family homes with outbuildings and the vegetation is mainly giass / pastme In the eastern section, the vegetation is mostly pastme with some forested areas having light under brnsh_ Generally, stormwater 1unoff from the site sheet flows from west to east thtough the vegetation, thtough the sensitive area tract, and into either the Class III Wetland along the northeastern comer of the site, or into Maplewood Creek. Runoff from the existing buildings are assumed to be released to the adjacent vegetation by downspout lines and/or just dripping off the edge of the roof In addition, stormwater runoff from Northeast 2"d Place sheet flows down the road easte1ly and either sheet flows into the sensitive meas uact and then into Maplewood Creek, 01 sheet flows directly into Maplewood Creek Per King County requirements, the pre-developed conditions are assumed to be histmic site conditions (fmcstcd). The table below shows the brnakdown of the areas for developed condition. Till-Pasture Total Basins (ac) (ac) Stte (includes frontage) 3.85 3.85 Sub-Total 3 85 3.85 Areas Not Collected Eastern end of NE 2nd Pl 000 0 11 Sensitive Areas Tract 0.00 0.43 Sub-Total 000 0 54 Total 3.85 4.39 Precipitation: Precipitation amounts aie found fwm the Isopluvial maps in Chapter 3 of the King County Stormwater Design Manual The 24-hour ptecipitation values for specific year events and the tainfall regions and scale factor are listed below. -20 - ESM JOB# 1352--001-006 Year 2 24-Hour P1eci 2.00-inches Rainfall Region = Seattle Scale Factor= 1.0 Unjon Property 10 25 100 2.90-inches 3.40-inches 3 .90-inches -21 - 19951 CONSlJLJIN'G ENGINfiBS lLC ::,:::::;--• l91$1<ii>'I 8olhllf, WA 98011 www.esmcivil.com l.,,<><!S..~ ,.,,, .. et- -·"'"'' P'(tT ' ""1 ..... 0 0 q TOPOGRAPHIC MAP UNION PROPERTY FIGURE 8 rd EXISTING HYO LOGY MAP UNION PROPERTY FIGURE 9 ESM JOB# 1352-001-006 Union Property Developed Hydrology: Ground cover for the proposed developed site will consist of impervious areas from roadways, homes, and sidewalks; and pervious area from landscaping and lawns (See Figure IO -Developed Hydrology Map). Fot preliminary design purposes, stormwater mnoff from the entire site (roads, landscaped areas, and buildings) rue proposed to be collected and conveyed via a closed pipe system to the detention/water quality facility in the southeastern section of the site. However for final engineeiing design, some of the roof downspouts may be released to sheet flow dhectly into the Class Ill Wetland in the no1theastern comer of the site (bypassing the detention facility) to maintain runoff flows to the existing wetland- It is assumed that 75 percent of the lots ru·e impervious. The developed conditions, including the frontage imp10vement ruea, aie as follows Till-Grass lmperv. Total Area Collected (ac) (ac) (ac) Site 0.90 2.95 3.85 Sub-Total 0.90 2.95 3.85 Areas Not Collected Sensitive Areas Tract 0.00 0.00 0.43 Eastern end of NE 2nd Pl 0.00 0.00 0.12 Sub-Total 0.00 0.00 0.55 Total 0.90 2.95 4.40 -24 - ! /1\ ,:, / I \i ' --- ' I \. \ SITE BOUNDARY \ .... , 17 , 18 . ) I L -• --_, '-, ~ -,.__--,i--:;:-___ , --~---.,:~ 1 ::\ ... ~~--,_ \..,,_••t0,9._ • --I-_/; ~J ;~M·•--···-i~~fr~ =r ~• • >-~., \ ----- 19 TRACT B i I 26' PRIVATE ROAD \ j _ _,_--4-1 5 ' 1 1 r . ' ' '-' ·1· -----r ' , ·'" ..... I '\ I I .l.ci r. J ---:; --, ____ ..,. _____ . ,----T---:. L r i , .1 6 ; ~ 9) ·: 1-/ ,,,, ;;: / -~ ·,:_ ,-~--...... ~ .... ·-'-'-_~_.:i·--:,. -. r·\ . ~--""" I /3 / •--,,-,; ---:J • 4 .:::::r--,_ ... _. ~~:.L : : : / ; ;," ]/ /' ;,,-,, /' ,. / I ',1 SCALE: 1" = 50 ~ -' --50 25 0 50 100 WJ'LEWOOD CREEK ··-· .=..-..::::;_~~ ::::-_.18,1 . ..___ -::::-.. \ ____;;--:::;;;._.~-~~....::....~~ .--··-.....: -· '----... .. ~ ~!=...-..:.: ~ ------=:::!"•· ' I / ' 34" 1 I -~-._-___ ,,, "" /)j~·\\; :, I ~ --';;'2J1(\\: \ 11 ;::::===+'-,·--=·~------: /'Ji,/ I > I '' r r·---~---:--------1 -/ -/'r:;;~:t· . i/ I i , 15 /: . . \ , : '/5 : / I I I, : ,/ : : ' -' '' ~-·\ I / I I -·:----I:-~.:. ... • 1s : I -\'"-\"t~+-1:. i I r .,. 14 . • : 1 . : 1, 2et' 1 • i I I ' . . . : : ' ' / : ____ }_ I \ \ ', I . I ' / f~:-c..~7--/-~'.-[ --:/f-r\\~---, / / I . : . : .·· . . I' j \: / 1· : .... /': . ~ i,;;:'.'--.) ' I ~ . : : ' 2 ;.-i' .,-_.,-".>' \ < d 10 : ,.,·;. I[ ;_/1·' ;rAACTF\ ·t:._~ ~ !STORM VAULT . , (.) ~ :) :~ : ~oi: ( 22 21 ,'I 1/' iL \_ ' ,/ I ~g/\l __ ..,;;:_-~~-:, '-i ·11 1 "'\, ·r"-n•-..:::::,_ ·' --,-·-i;._-,. ) t i __ ~~-c· ,-r-~~ x ( 1··5 1 e ~::j I 'Fl t. r ·-~ _ 4 , '..... ' ! . . '! ' -----·--! , t _:, ' \ - " \\ n " a. < :::; >-~ t') ~J 0 ...I 0 a: 0 -Cl >-cc ii! :i: ~ 2 Cl w 0 a. 0 z ...I w :::> > w Cl ~ m ! * m ri -i p • Ill ·l --' l i . ·1· ! i• I ! If ! i ~ i~; il .;1!11 - -; I ti ! a I r i 11 ll :11 ,- i . ESM JOB# 1352-001-006 Union Property Flow Control System: Calculations for the proposed project me based on the 2005 King County Surface Water Design Manual (2005 KCSWDM) The project is located in a Conse1vation FC A:Ieas flow control atea. Detention and water quality treatment is ptoposed to be provided for in a detention vault located in the southeastern comer of the site {See Figure 10). In accordance with the Conse1vation FC A:Ieas 1equitements, the design intent for the detention facility is to match the developed durntion levels to the existing duiation levels for the following ranges: • 2-year developed to 50% of the histo1ic 2-yeat duration and • SO-year developed to the historic 50-yeat· duration In addition, you have to match the peak flows fat the developed facility to the existing flows for the following 1anges: • 2-year developed peak to the historic 2-yem· peak and • 10-yeat developed peak to the hist01ic 10-yeat peak. Existing Basin Flows: Basin data is entered into KCRIS for the site (including Southeast 2"d Place) to obtain individual time series. Results of entering the existing basin date into KCRTS ate as follows. Flow F~equency Analysis rime Series Iile:pre .. tsf Pxoject Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks Rank Retur:n Prob {CFS) (CFS) Peiiod 0.243 2 2/09/01 18,00 o. 311 1 100.00 0 990 0.066 7 1 /06/02 3:00 0 .243 2 25 .. 00 o. 960 0.180 4 2/28/03 3,00 0 .187 3 10 00 0 900 0.006 8 3/24/04 20: 00 0 180 • 5.00 0 .. BOO 0.107 6 1/05/05 8,00 0. 157 5 3 00 0. 667 0 187 3 1/18/06 21:DO 0 .107 6 2.00 0.500 0.157 5 11/24/06 4,00 0 066 ) 1.30 0.231 0.311 1 1/09/08 9:00 0.006 8 1 .10 0.091 Computed Peaks 0.288 50 00 0 .. 980 Developed Basin Flows: Similat to the existing conditions analysis, basin data is ente1ed into KCRT S for the site (including Southeast 2nd Place) to obtain a time se1ies Results of entering the developed basin data into KCRTS is as follows Flow Frequency Analysis lime Series Eile:dev tsf Ptoject Location:Sea-Tac ---Annual Peak Elow Rates--- Flow Rate Rank Time of Peak {CFS) 0.796 6 2/09/01 2:00 -----rlow Frequency Analysis---· -Peaks Rank Return Prob (CFS} Period 1.58 l 100.DO O 990 -26 - ESM JOB# !352--001-006 0. 671 8 1/05/02 16:00 1.10 2 0.952 3 2/27 /03 7:00 0.952 3 0. 752 ) 8/26/04 2:00 0.899 4 0 .. 899 4 10/28/04 16:00 0 847 5 0.847 5 1/18/06 16: 00 0 . 796 6 1..10 2 10/26/06 0:00 0 752 7 1.58 1 1/09/08 6:00 0. 671 8 Computed Peaks 1.42 Facility Design: The following detention calculations aie printouts ofKCRTS. Retention/Detention Facility Type of Facility: Detention Vault Facility Length: 101.00 ft Facility Width: 108.00 ft Facility A:rea: 10 908 sq. ft Effective Storage Depth: 5. 00 ft Stage O Elevation: 100 .00 ft Stoiage Volume: 54540. cu. ft RiseI Head: 5 .. 00 ft Riser Diameter: 13 .. 00 inches Numbe:r of orifices: 3 Union Property 25.00 0.960 10.00 0.900 5 00 0 .. 800 3.00 0 .. 667 2.00 0.500 1 30 0.231 1.10 0.091 SO.DO 0 .. 980. full Head Pipe Orifice # Height Diarnete:r Discharge Diametei:: (ft) (in) (Cf S) (in) l 0.00 1 06 0 .. 069 2 3 00 1. 81 0 .. 126 4 .. 0 3 4 .. 45 l .50 0.045 4 .0 Top Notch Weir: None Outflow Rating Curve: Nc~e Stage Elevation Storage Discharge Percolation ( ft) (ft) (cu .. ft) (ac-ft) (cfs) (cfs) 0.00 100 .. 00 0. 0.000 0.000 0 .. 00 0 .. 01 100 .. 01 109 0.003 0 .. 003 0 .00 0.02 100 .. 02 218. 0.005 0.005 0 00 0.03 100.03 32 7. 0.008 0 .. 006 0 00 0 .. 04 100.04 436. 0 .. 010 0 .. 006 0.00 0 .. 06 100.06 655. 0 015 0.007 0.00 0.07 100.07 764 0.018 0.008 0.00 0 08 100.08 873. 0.020 0 009 0.00 0 .. 09 100.09 982. 0 .. 023 0.009 0.00 0 .. 19 100 .. 19 2073. 0 .. 048 0. 013 0.00 0 .. 29 100 .. 29 3163. 0.073 0 .. 016 0 .. 00 0 .. 39 100 .. 39 4254 0 098 0.019 0 .. 00 0 49 100. 4 9 5345 0 .. 123 0.021 0.00 D .59 100.59 6436 .. 0 .. 148 0 024 0 .00 0 . 69 100 .69 752 7 .. 0 .173 0 .025 0 OD 0 .. 79 100 .. 79 861 7 .. 0 .. 198 0 .. 027 0 .. 00 0.89 100 .. 89 9 708. 0.223 0 .029 0 .. 00 0 .. 99 100. gg l O Jgg . 0.248 0 .030 0 .. 00 1.09 101..09 118 90. 0 .273 0 .. 032 0.00 1.19 101..19 12981 0 .298 0.033 0.00 1.29 101.29 14071 0 .323 0 035 0.00 -27 - r ESM JOB# 1352-001-006 1.39 L49 l.59 1 69 L 79 l.89 1 99 2.09 2.19 2 .29 2.39 2. 49 2.59 2.69 2 79 2.89 2.99 3.00 3.02 3.04 3.06 3.08 3 .. 09 3 .11 3.13 3.15 3.17 3. 2 7 3 .. 37 3.47 3.57 3.67 3. 77 3.87 3.97 4 .. 0 7 4 17 4.27 4 .. 37 4.45 4.47 4 48 4.50 4 . 51 4.53 4 . 54 4.56 4 .. 5 7 4.67 4. 77 4.87 4.97 5.00 5 .. 10 5 .20 5.30 5 .40 101.39 101.49 101.59 101. 69 101. 79 101.89 101.99 102 .. 09 102.19 102.29 102.39 102 .. 49 102 .. 59 102 .. 69 102 .. 79 102 .. 89 102.99 103.00 103.02 103.04 103.06 103 .. 08 103.09 103. ll 103.13 103 .. 15 103.17 103.27 103.37 103.47 103.57 103 .. 6 7 103 .. 77 103. 8 7 103.97 104.07 104.17 104 . 2 7 104.37 104 .. 45 104 4 7 104.48 104 . 50 104.51 104.53 104.54 104 .. 5 6 104.57 104. 67 104 . 7 7 104 .. 87 104 97 105.00 105.10 105.20 105 .. 30 105 .. 40 15162. 162 5 3 .. 17344. )8435. 19525 .. 20616. 21107. 22 798. 23889 .. 24979. 26070. 27161.. 28252 29343 .. 30433. 31524. 32615. 32 724 .. 32 942 33:60. 33378. 33597 33706. 33924. 34142 .. 34360 .. 34 5 78. 35669 .. 36 7 60 .. 37851 38942 .. 4 0032 .. 41123. 42214. 433C5 44396 .. 45486. 46577. 47668 .. 48541 48759 .. 48868 .. 4 9C 8 6 . 49195. 4 9413 4 9522 .. 49740. 49850. 50940. 52031 .. 53122 54213 SL.'140" 55631. 56722. 57812 58903 -28 - 0 348 0.373 0.398 0.423 0 448 0 .. 473 0. 498 0 .. 523 0. 548 0.573 0 .. 598 0.624 0 .. 649 0.674 0.699 0. 724 0. 749 0. 751 0 .. 156 0 .. 761 0 .. 766 0. 771 0. 774 0. 779 0. 784 O. 78 9 0 .. 794 0 .. 819 0.844 0.869 0.894 0.919 0.944 0. 969 0 .. 994 1.. 019 1.044 1.. 069 1.. 094 1.114 1..119 1.122 1 .. 12 7 1.129 1..134 1..137 1..142 1 .144 1.169 1.194 1.220 1..245 1.252 1..2 77 1.302 1.327 1.352 0.036 0 .. 03 7 0 .. 039 0. 040 0.041 0 .. 042 0 .. 043 0.044 0.045 0.046 0.047 0.048 0.049 0.050 0.051 0.052 0.053 0.053 0.054 0.056 0.060 0.065 0. 071 0.078 O. 086 0 .. 089 0.091 0.102 0.110 0 .118 0 125 0.132 0 .. 138 0.143 0 .149 0.154 0 .. 159 0.164 0.168 0.172 0 .173 0.175 0.178 0.182 0 .. 18 7 0 .. 193 0.197 0.199 0.211 0.221 0.230 0.238 0.240 o. 710 1.560 2.660 3. 960 0.00 0.00 0 . 00 0.00 0 .. 00 0 .. 00 0 .. 00 0.00 0.00 0.00 0.00 0.00 o.oo 0.00 0.00 0.00 0. 00 0 .. 00 0 .. 00 0 .. 00 0 .. 00 0 .. 00 0.00 0.00 0.00 0 .. 00 0.00 0 .. 00 0 .. 00 0 .. 00 0 .. 00 0.00 0.00 0.00 0.00 0.00 0 .. 00 0.00 0 .. 00 0.00 0.00 0.00 0 .. 00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .. 00 0 ., 00 0 .. 00 0.00 0.00 0 00 Union Property ESM JOB# 1352-001-006 Union Property 5 . 50 105 . 50 59994 . l. 3 77 5 .440 0.00 5 .. 60 105 .. 60 61085 l 402 6 .. 870 0 .. 00 5.70 105 .. 70 62176. 1.427 7 .. 410 0 .. 00 5.80 105 .. 80 63266 .. 1.452 7 .. 910 o .. 00 5 .. 90 105 .90 64357 .. 1..477 8.370 0 .. 00 6 .. 00 106 .00 65448 L 502 8 .. 810 0 .. 00 6.10 106 .10 66539 1 .. 528 9.240 0 .. 00 6 20 106 .20 67630 l .. 553 9.640 0 00 6.30 106 .30 68720 1.578 10.020 0.00 6.40 106 .40 69811. 1.603 10.400 0.00 6 .. 50 106 .. 50 70902 .. 1.628 10. 750 0 .. 00 6.60 106 .. 60 71993 .. 1.653 11.100 0.00 6. 70 106. 70 73CB4. L678 11.440 0.00 6.80 106.80 74174. L 703 lL 760 0.00 6.90 106.90 75265. l. 728 12.080 0.00 7 .00 107.00 7 6356. L 753 12. 390 0 .. 00 Hyd Inflow Outflow Peak Storage Target Cale Stage 1 1.58 0.31 0.87 5.12 2 0 . 80 ******* 0 .. 24 4 .. 97 3 1.10 ******* 0.17 4 . 34 4 0.95 ******* 0.16 4 .. 29 5 0.85 ***·*"'"*+ 0.12 3 . 51 6 o .. 90 ******* 0.06 3 . 04 7 0.67 ******* 0.05 2. 96 8 o. 75 ******* 0 .. 04 2 .12 Route Time Series through Facility Inflow Time Series File:dev .. tsf Outflow Time Series File:rdout Elev (Cu-Ft) (Ac-Ft) 105 .. 12 55841. 1 282 104 .. 97 5424 9 .. 1.245 104 .. 34 4 7307 .. 1.086 104.. 29 46788 .. 1.074 103 .. 51 38260 0.878 103.04 331 72 .. o. 762 102. 96 32294 .. 0. 741 102.12 23075 .. 0.530 Inflow/Outflow Analysis Peak Inflow Discharge: i .. 58 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge; Peak Reservoir Stage: 0.875 5 .12 Peak Resexvoir Elev: 105 .. 12 Peak Reservoir Storage: 55841.. 1 Flow Frequency Analysis Time Series Eile:rdout.tsf Project Location:Sea-Tac .282 CFS at 10:00 on Jan 9 in Year 8 Ft Ft Cu-Ft Ac-Ft ---Annual Peak Flow Rates--------flow Frequency Analysis------- Flow Rate Rank Time of Peak --Pea ks --Rank Retux·n Prob (CFS) (CFS) (ft) Period 0.238 2 2/09/01 20:00 0.875 5.12 1 100.00 0 .. 990 0.053 7 1/07/02 4:00 o.238 4.97 2 zs_oo o.960 0_165 4 3/06/03 22:00 0.167 4.34 3 10.00 0.900 0.044 8 8/26/04 7:00 0.165 4.29 4 5.00 0 . 800 0 .. 056 6 1/08/05 5:00 0 .121 3.51 5 3.00 0 .. 667 0.121 5 1/18/06 23:00 0 .056 3.04 6 2.00 0 .500 0.167 3 11/24/06 8:00 0 .053 2. 96 7 1 30 0 .231 0.875 l 1/09/08 10:00 0 . 044 2.12 8 1 .10 0 .091 Computed Peaks 0 .663 5.09 50 .00 0 .980 -29 - ESMJOB# 1352-001-006 Union Property Flow Duration from Time Seiies File:rdout.tsf Cutoff Count Frequency CDF Exceedence_Probability CfS % % % 0.003 27856 45.427 45. 427 54.573 0.010 7423 12.105 57.533 42.467 0.017 6787 11.068 68.601 31.399 0 .. 023 5406 8 .. 816 77 .417 22.583 0.030 5629 9.180 86.597 13.403 0.037 3529 5.755 92 .. 352 7.648 0.043 1947 3.175 95.527 4.473 0.050 1753 2.859 98. 386 1.614 0.057 600 0.978 99.364 0.636 0.064 31 0.051 99.415 0.585 0.070 15 0.024 99 .. 439 0.561 0.077 14 0.023 99.462 0.538 0.084 8 0.013 99 475 0.525 0.090 25 0.041 99.516 0.484 0 .. 097 45 0.073 99.589 0 .. 411 0 .. 104 34 0.055 99.644 0.356 0 110 32 0.052 99 .697 0.303 0.117 28 0 .. 046 99.742 0.258 0 .. 124 28 0.046 99.788 0.212 0.130 16 0.026 99.814 0.186 0.137 12 0.020 99.834 0.166 0.144 16 0.026 99.860 0.140 0 .. 150 14 0.023 Y9.883 0 .. 117 0.157 14 0 .. 023 99.905 0.095 0.164 17 0.028 99.933 0.067 0.170 22 0 036 99.969 0 .. 031 0.177 3 0 005 99. 974 0.026 0.184 0 0.000 99.974 0.026 0.190 0 0 .. 000 99 914 0.026 0.197 1 0 002 99.976 0.024 0 .204 2 0.003 99. 979 0 .021 0.211 1 0.002 99.980 0_020 0 .. 217 2 0.003 99.984 0 .. 016 0.224 3 0.005 99 989 0.011 0.231 2 0.003 99. 992 0 .. 008 0.237 4 0.007 99 998 0.002 Duration Comparison Anaylsis Base File! pie.tsf New File: rdout.tsf Cutoff Units: Discharge in CFS 0.546E+OO 0 .. 425E+OO 0.314E+OO 0.226E+OO 0.134E+OO 0.765E-01 0 .. 44 7E-01 O .161E-Ol 0 .. 636E-02 0.585E-02 0.561E-02 0.538E-02 0.525E-02 0.484E-02 0 .. 411E-02 0.356E-02 0 .. 303E-02 0.258E-02 0.212E-02 0.186E-02 0.166E-02 0.140E-02 0.117E-02 0.946£-03 0.669E-03 0.310E-03 0. 261E-03 0.261E-03 0 .. 261E-03 0.245E-03 0 .. 212E-03 0. l 96E-03 0 163E-03 0 .114£-03 0 .. 815E-04 0. 163E-04 -----Fraction of Time--------------Check of Tolerance----- Cutoff %Change 0.054 I 0.068 I 0 .. 083 I o .097 I 0 .. 112 I 0.126 I 0.141 I 0.155 I Base 0 .. 93E-02 0.62E-02 0.48E-02 0.37E-D2 0.28E-02 0.22E-02 O .. lSE-02 0.lOE-02 New 0.69E-02 0 .. 57E-02 0.SJE-02 0.41E-0:0 0. 29E-D2 0.20E-02 0.15E-D2 0.99E-03 %Change Probability -25.3 -8. 6 8 4 11. 6 2. 9 -9.7 2 2 -1. 6 -30 - 0.93E-02 0. 62E-02 0 .. 48E-02 0.37E-02 0.28E-02 0.22E-02 0.lSE-02 O.lOE-02 0.054 0.068 0.083 0 097 o. 112 0.126 0 141 0.155 Base 0.052 0.058 0.090 0.103 0 .. 113 0.122 0 .142 0 .. 155 New -3 .. 1 -15 .. 2 8.7 5.4 1.3 -3. 2 0.6 -0.1 ESM JOB# 1352-001-006 0.170 0 .62E-03 0 .. 34E-03 -44 J 0. 62E-03 0.184 0. 34E-03 0.26E-03 -23. 8 0 .. 34E-03 0.199 0 21E-03 0 .. 24E-03 15 .4 0 .. 21E-03 0 .. 213 0.16E-03 0 .. lBE-03 10 0 0.16E-03 0.228 0. llE-03 0.98E-04 -H .. 3 0.llE-03 0 .. 242 0.16E-04 0 .. OOE+OO -100.0 0.16E-04 Maximum positive excursion= 0 .. 007 cfs 9-1%) occur:r ing at O ., 081 cfs on the Base 9a ta: p:re _ tsf and at 0.088 cfs on the New Data:r:dout.tsf Maximum negative excursion= 0.011 cfs (-15.9%) occurring at 0_067 cfs on the Base Data:pxe.tsf and at Q_D56 cfs on the New Data:rdout.tsf Union Property 0.170 0 .164 -3.3 0 .. 184 0 . l 70 -7 9 0 .. 199 0 .207 3.9 0 .213 0. 218 1.9 0 .. 228 0.227 -0.4 0 .. 242 0.238 -1..9 The proposed detention facility is latger than that produced from the analysis above. l'l:imaty Overflow: This is a Preliminary Technical Information Report Theiefore, the primary oveiflow will not be provided at this time. Secondaty Overflow: 1bis is a Preliminary Technical Information Report Therefore, the secondary overflow will not be provided at this time .. Emergency Overflow: 1bis is al'l:eliminary Technical Information Report. The1efore, the emergency oveiflow will not be provided at this time .. Water Quality System: The project is located in the Basic Water Quality Treatment Area per the King County Water Quality Applications Map The water quality facility will be in the f01m of dead storage in the bottom of the detention pond. The design intent for the water quality facility is 80 percent removal of total suspended solids (ISS). Facility Design: The facility is sized pet Chapter 64 of the 1998 KCSWDM using a Basic Wetpond design. The following equations are used to size the wale! quality facility .. Calculation of the mean annual storm is as follows. V, =(09A,+0.25A,, +0.lOA,1 +OO!A,)xR Wheie: A, = 2.95 ac = 128,502 sf A,, = 0 . .90 ac = 39,204 sf (Tributary area ofimpervious surface) (Ttibutary ru·ea of till giass & pasture surface) -31 - ESM JOB# 1352-001-006 Union Property ~ =Oac =Osf (T ,ibutary area of till forest surface) A .. = 0 ac = Osf (T1ibutary ar·ea of outwash grass surface) R = 0.47 inches (Rainfall from mean annual storm) V, = Volume of runoff from mean annual storm ( cf) V, = [(09x 128,502) + (025 x 39,204) + (0 !Ox 0) + (0.01 x 0)}:0.47)/12 v, = 4,91357 cf Calculate wetpool volume is as follows V,=fxV, f = 3 (Basic Wetpond) V, = 4,91357 cf (Calculated above) V, = Minimum pond volume ( cf) Vb = 3 X 4,913.57 = 14,740 .. 04 Cf The provided dead stmage volume in the bottom of the proposed vault will be at least the 1equired volume .. -32 - c ESM JOB# 1352-001-006 Union Property 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN This is a Preliminary Technical Information Report. Iherefoie, conveyance analysis will not be provided at this time. -33 - ESM JOB# 1352--001-006 Union Property 6. SPECIAL REPORTS AND STUDIES The following lists are the known reports and studies done for the project. These reports may be found in Appendix A. Report f Study I By Dated Wetland Report I Chad Annom, LLC January 24, 2007 -34 - ESM JOB# )352-001-006 Union Property 7. OTHER PERMITS This is a Preliminary Technical Information Report Therefore, other peimits will not be provided at this time. -35 - i- i ; ESM JOB# 1352-001-006 Unjon Property 8. ESC ANALYSIS AND DESIGN This is a Preliminary Technical Information Repmt Therefme, ESC analysis and design will not be provided at this time. -36 - ESM JOB# 1352-001-006 Union Property 9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT This is a Preliminary Technical Information Repo1t. Therefore, bond quantities, facility summaries, and decimation of covenant will not be provided at this time .. -37 - ' I ESM JOB# 1352-001-006 Union Property 10. OPERATIONS AND MAINTENANCE MANUAL This is a Preliminary Technical Information Report. Therefore, opetations and maintenance manual information will not be provided at this time. -38 - ' r APPENDIX A CHAD ARMOUR, LLC February 26, 2007 Job No. 07-001 Mr. Michael Gladstein American Classic Homes P. 0. Box 1830 Renton, Washington 98055 6500 126'" Avenue S. E. Bellevue, Washington 98006-3941 (425) 641-9743 Office (425) 643-3499 Fax chad@chadannour.com Subject: Critical Areas Assessment and Delineation Rosewood Highlands Preliminary Plat Renton, Washington Dear Mr. Gladstein: We are pleased to present the results of our critical areas (wetland and stream) assessment and delineation for the above-referenced property located in Renton, Washington (Figure 1). The work was accomplished in accordance with our proposal (No. 241) dated January 3, 2007. The purpose of the work is to assist you to identify the size and location of wetlands and streams on the subject property. The report is organized in sections and includes: SUMMARY OF FINDINGS that presents a synopsis of the pertinent issues related to wetlands and streams; SITE DESCRIPTION of the subject property (site) and adjacent properties; BACKGROUND INFORMATION that presents existing information about the site and surrounding area; SITE CONDITIONS that describes wetlands, streams, and uplands; CONCLUSIONS that summarize the results of our critical areas assessment and delineation; and LIMITATIONS of this project. References, tables, figures, and appendices follow the text. Table 1 lists the plants observed on and near the site. Figure 1 is a Vicinity Map showing the location of the site and pertinent surrounding features. Figure 2 is a Site Plan that shows the location of wetlands, streams, sampling points, and other pertinent site features. The soil type mapped for the site is shown on Figure 3. Appendix A contains assessment methods and field data forms. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC 02/26/07 Critical Areas Assessment and Delineation Renton, Washington SUMMARY OF FINDINGS Rosewood Highlands Preliminary Plat American Classic Homes proposes to develop the 4.39-acre (ac) site so that as many as 27 homes can be constructed. Most of the site is upland. A total of 1,543 square feet (sf) of the site is occupied by a Category 3 wetland. Most of this wetland is located off of the site. The standard buffer for Category 3 wetlands is 25 feet (ft). A Class 4 stream flows across the site along its eastern boundary. The standard buffer for Class 4 streams is 35 ft. SITE DESCRIPTION Site The 4.39 ac site is located at 224 Union Avenue in Renton, Washington, in Section 15, Township 23 North, Range 5 East, Willamette Meridian (Figure 1). The site, which occupies six parcels (Nos. 518210-0068, 518210-0069, 518210-0073, 518210-0079, 518210-0081, and 518210-0085), is the location of several single-family homes, mowed lawn, forest, and a stream. Site elevations range from about 384 ft where the stream leaves the site to about 410 ft above mean sea level near the western edge of the site (ESM Consulting Engineers LLC, 2007). Adjacent Property In general, the area in the vicinity of the site is represented by single-family residences. To the east are new homes on small lots. Homes on medium-sized lots and NE 2"d Place are located south of the site. A park that is under construction is located to the west. A wetland and property in the process of being filled are located north of the site. A relatively new stormwater pond is located on the property being filled. BACKGROUND INFORMATION The following sections of the report portray known available information about wetlands, streams, and other infonnation about the site and surrounding area. Site Development Plan We understand that American Classic Homes plans to divide the site so that up to 27 single-family homes may be constructed (Figure 2). Wetlands and Streams The National Wetland Inventory (NWI) map shows no wetlands on or near the site (FWS, 2007). The King County iMap shows an unclassified stream flowing across the site. The same map shows a wetland located about 1,500 feet (ft) east of the site (King County, 2007). The Washington State Department of Natural Resources (DNR) Forest Practice Activity map shows no stream on the site. The same map shows a fish-bearing stream about 500 ft southeast of the site (DNR, 2007). The Stream net map also shows no stream on or near the site. The closest stream mapped by Streamnet is the Cedar River (Streamnet, 2007). The City of Renton's (City) Storm-Surface Water map shows a C:IESM/RoseM/etland Delineation Report.doc Chad Armour, LLC 2 02/26/07 Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat stream (Maplewood Creek) originating north of the site immediately south of NE 4th Street (Renton, 2005). Soils The King County soil survey indicates that the site supports one soil type, Aldeiwood gravelly sandy loam, 6 to 15 percent slopes (Figure 3). Alderwood Soil Series Alderwood soils are made up of moderately well drained soils underlain by a dense till layer typically two to 3.5 fl below the surface. Alderwood soils formed in glacial deposits under conifer trees. In a representative profile, the surface layer is dark brown (10YR 4/3) gravelly sandy loam about 12 inches (in) thick. The subsoil is grayish brown (2.5Y 5/2) gravelly sandy loam (Snyder et al., 1973). Till is a barrier that retards the downward percolation of the rain that falls on the soil. When the soil above the till layer becomes saturated, water that accumulates on the till surface will pool in depressions or flow in the direction of the gradient. The general subsurface flow is ultimately concentrated in depressions or streams. Alderwood gravelly sandy loam is not a listed hydric soil (NRCS, 1996). SITE CONDITIONS We visited the site on January 22, 2007 to assess upland, stream, and wetland conditions on and adjacent to the site. The following sections of the report describe the upland and wetland plant communities located on and/or adjacent to the site and the physical attributes of the stream. Uplands At least four upland plant communities are present on the site. Most of the site is represented by mowed grass and associated ornamental landscaping (Appendix A; Plot ID SP-2). This area represents the relatively flat western 80 percent of the site. Smaller areas of the site are occupied by deciduous forest, Himalayan blackberry, and reed canarygrass (Table 1 ). Deciduous Forest The forested plant communities are located in the southeast and northeast corners of the site. In the southeast corner of the site the plant community is the location of widely scattered black cottonwood, big-leaf maple, western red cedar, and red alder trees. Growing under the tree canopy are a thick tangle of Himalayan blackberry shrubs and some hazelnut, Scot's broom, hardhack, and vine maple shrubs. The plant community in the northeast corner of the site has black cottonwood rooted at the top and toe of the slope (the toe forms the southern edge of the adjacent wetland). Widely scattered big-leaf maple and red alder trees are rooted on the slope as are a thick tangle of Himalayan blackberry shrubs and the occasional clump of Japanese knotweed. CJESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC 3 02126/07 Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat Himalayan Blackberry Plant Community The moderate slope east of the mowed lawn is covered with a thick tangle of Himalayan blackberry shrubs. A few black cottonwood trees are also rooted on the slope. Reed Canarygrass Plant Community The 30-feet-wide ground east of the Himalayan blackberry plant community and west of the on-site stream is the location of a reed canarygrass plant community. Also present are some encroaching Himalayan blackberry canes and the occasional hairy cat's-ear, soft rush, and western water hemlock. This area is regularly mowed presumably as part of a maintenance program. The plants are rooted in very sandy very gravelly fill soil. The soil was saturated to the surface (Plot ID SP-1). Streams The west branch of Maplewood Creek flows across the site along the site's eastern boundary. Although this stream has been around for a long time, it clearly has been manipulated by humans in the recent past. It originates from a large pipe located under NE 4th Street. From there it flows through a wetland, most of which is located on the property north of the site. It then flows across the site in ari engineered channel. A near vertical slope .fonms its eastern bank and fill associated with a buried sewer pipe its western bank. The stream continues to flow south of the site in a fairly linear fashion. We did not observe fish in the stream. On the sije the silt-bottomed stream averages 7 .8 ft wide (range 5 to 11 ft) and 14.1 in deep (range 6.5 to 21 in). The east bank of the stream is draped with Himalayan blackberry shrubs. The west bank supports the mowed reed canarygrass plant community. The mowed area averaged about 30 feet wide. Stream Classification and Buffers Based on the physical characteristics of the stream and the setback for the adjacent residential development to the east, the on-site reach of the west branch Maplewood Creek is classified as a Class 4 steam (RMC 4-3-050L 1 aiv). The standard buffer width for Class 4 steams is 35 ft (RMC 4-3-050L5aic). Wetlands We flagged one wetland on the site and ESM Consulting Engineers surveyed the flagged wetland boundaries. The west branch of Maplewood Creek flows through the wetland. This riverine forested wetland (Cowardin et. al., 1979) is a part of a larger wetland that extends off site to the north. It supports widely scattered black cottonwood and red alder trees ranging from about 12 to 20 in in diameter. Western crabapple, red-osier dogwood, and hardhack shrubs grow under the tree canopy. Small stands of reed canarygrass occupy flats adjacent to the stream. The on-site portion of the wetland covers 1,543 sf (Figure 2). What appears to be a temporary stormwater facility is located about 25 ft east of .the wetland. C:/ESM/RoseNVeUand Delineation Report.doc Chad Armour, LLC 4 02126/07 Critical Areas Assessment and Delineation Renton, Washington Wetland Functions, Classification, and Buffers Rosewood Highlands Preliminary Plat We performed a functional assessment of the wetland using the Washington State Department of Ecology's (Ecology) wetland rating form for western Washington (Hruby, 2004). When we examine their individual attributes, the wetland provides high water quality functions, and moderate hydrologic and habitat functions. Based on the criteria set forth in the City's municipal code and the buffer associated with the stormwater pond to the north, the wetland meets the criteria for a Category 3 wetland (RMC 4-3- 050M1 aiii). The outlet of the wetland has been modified. Fill associated with a buried utility line has narrowed the outlet. The standard buffer width for Category 3 wetlands is 25 ft (RMC 4-3-050M6ci). CONCLUSIONS Most of the 4.39 ac site is upland. A part of a Category 3 wetland is located in the northeast corner of the site. Most of this wetland is located off of the site to the north. A Class 4 stream flows across the eastern edge of the site. The stream flows through the wetland. LIMITATIONS Work for this project was performed, and this letter report prepared, in accordance with generally accepted professional practices for the nature and conditions of the work completed in the same or similar localities, at the time the work was performed. It is intended for the exclusive use of American Classic Homes and their assigns for specific application to the referenced property. This report is not meant to represent a legal opinion. No other warranty, express or implied, is made. It should be noted that Chad Armour relied on information provided by others indicated previously. Chad Armour can only relay this information and cannot be responsible for its accuracy or completeness. Also note that delineating wetlands and streams, and assessing functions and values are inexact sciences. Biological professionals may disagree on the precise location of wetland and stream boundaries, their functions, and classification. The final determination of these characteristics is the responsibility of the permitting authority. Accordingly, the wetland and stream assessment and delineation performed for this study, as well as the conclusions drawn in this report, should be reviewed by the appropriate permitting authority prior to committing to detailed planning and design activities. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC 5 02/26/07 Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat Any questions regarding our work and this report, the presentation of the information, and the interpretation of the data are welcome and should be referred to the undersigned. Sincerely, Chad Armour, LLC ~4>'·~~ Chad Armour Principal Attachments: References ) Table 1 -Plants Identified on and adjacent to the Rosewood Highlands site Figure 1 -Vicinity Map Figure 2 -Site Plan Figure 3 -Soils Map Appendix A -Assessment Methods and Routine Wetland Detem,ination Data Fom,s C:/ESM/Rose/WeHand Delineation Report.doc Chad Armour, LLC 6 02/26/07 REFERENCES Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat REFERENCES Cooke, S.S. 1997. A Field Guide to the Common Wetland Plants of Western Washington and Northwestern Oregon. University of Washington Press. Cowardin, L. M., V. Carter, F. C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Department of the· Interior, Fish and Wildlife Service, Office of Biological Services. DNR (Washington State Department of Natural Resources). 2007. Forest Practices Application Review System for Township 23N, Range 5E, Sections 15. http://www3.wadnr.gov/dnrapp5/website/fpars/viewer.htm. Ecology (Washington Department of Ecology). 1997. Washington State Wetlands Identification and Delineation Manual. Publication No. 96-94. 88 pages plus appendices. Environmental Laboratory. 1987. U.S. Army Corps of Engineers Wetlands Delineation Manual, Technical Report Y-87-1, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. ESM Consulting Engineers. 2007. Preliminary Plat. Job No. 1352-001-006. FWS (U. S. Fish and Wildlife Service). 2007. Wetlands On-line Mapper. http://www.wetlandsfws.er.usgs.gov. Hitchcock, C. L. and A. Cronquist. 1973. Flora of the Pacific Northwest. University of Washington Press. Hruby, T. 2004. Washington State wetland rating system for western Washington - Revised. Washington State Department of Ecology Publication# 04-06-025. King County. 2007. iMap. http://www5.metrokc.gov/servlet/map output.him. NRCS (U.S. Department of Agriculture Natural Resources Conservation Service). 1996. Hydric Soils of the United States. http://www~statlab.iastate.edu/soils/hydric/national.html. Reed, P. B., Jr. 1988. National List of Plant Species That Occur in Wetlands: Northwest (Region 9). US Fish and Wildlife Service, Biological Report 88(26.9). 89 pages. Renton, City of. 2005. Storm-Surface Water map. Planning/Building/Public Works. Renton. 2005a. Tille IV Development Regulations, Chapter 3 Environmental Regulations and Overlay Districts, 4-3-050 -Critical Areas Regulations. Snyder, D. E., P. S. Gale, and R. F. Pringle. 1973. Soil Survey of King County Area, Washington. USDA Soil Conservation Service in cooperation with Washington Agricultural Experiment Station. 100+ pages plus maps. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC 02/26/07 Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat Streamnet. 2007. NWR Critical Habitat Mapper. http://www.streamnet.org. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC 02/26/07 TABLES Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat big-leaf maple black cottonwood grass hairy cat's-ear hardhack hazelnut Himalayan blackberry Japanese knotweed red alder red-osier dogwood reed canarygrass Scot's broom soft rush vine maple western crabapple western red cedar western water-hemlock Hypochaeris radicata Spiraea doug/asii Cory/us cornuta Rubus discolor Po/ygonum cuspidatum A/nus rubra Camus stolonifera Phalaris arundinacea Cytisus scoparius Juncus effusus Acer circinatum Ma/us fusca Thuja plicata Cicuta dou /asii Refer to Appendix A for an explanation of Indicator Status. C:/ESM/Rose/Wetland Delineation Report.doc Chad Armour, LLC FACU FAC FACU FACW FACU FACU FACU FAC FACW FACW FACU FACW FAC- FACW FAC OBL 02/26/07 FIGURES "8 ~ C l m E Source: The Thomas Guide, 2002, King/Pierce/Snohomish Counties: Page 656. NOTTO SCALE i ·; ._ _____________________________________________ __J g ·i FIGURE 1: VICINITY MAP ~ 5 .Rosewood Highlands Preliminary ~ Renton, Washington Chad Armour, LLC 6500 125• Avenue SE Bellevue, Washington 98006 l I I \ ' ' 'j .. ·,!_ : :) 3! z~ ' ~~ l: .:;c:~ ii z?: .,. Q~ ,I z ·! :J ·:I. I .-\' ;\. ' 1 /' 1/ t· f~ \..r----t,,, . l:. ) ! ,·--1 -i . __ ,:_,,). ' ' ,, ·r;'!; , .. :'--· "-~f -. ---405-· .. -::-:-=·.-,-·· >'' cf-' ', ~~.L:: ,, I 17 1\ --,,~, -·~-~"T~- 18 TRACT 20' J.U.O. 19 ,,,,/ ., ,'I ' / 20-21 ,o' / ' ~ 'i, 23 :.~-- ,t,·;;-",' ,., ,··lt.:,;. 1..qr, .. ,' Sl(1rn11"'l"lfl• Pund ,, li\ ,, I j: ·x-·----" ,, I ;: ·'""" ~ I I,,;: i . : ltt::f . ,. 1' ?; ,t' '' .. '2. '' ~,'// ~ \ 1 I ,i \: I ' I ;!'1. : , I • :_; : \ I . Ii I/ I i1 1/ I :/! 1-ll>\l./ I ii! t~! .... -<,(,,~:c,-.::CT A r..1 · -_ ~ T\t ... ;J.U.D. i~ I . 'r' · .. -: ·-,oe·· .· .::.....::i .. ::;,:-:·,·,~ ccc· cc.•~·""'· ··-,.;.~~-,. l& ··,··, -rr·· -,~~A?.-·---·,uo· 1-·-· --·-, ~-"• --~-~-::,:.:~~/1'!1.~-.:··~--2,_·J / ? ·. _"_r_i!f'A~u-~~f~l2;;.~l~~: . ·:'f -~ 1 J 25 ' I ,. I 15., ·:<i' • Suffer/ ;t a / · i[i : 1 ~ " ' 13 ·2,6., I j 15 j' ' · · ~ / · ' • I, .. ,_,_ I 14 s I "! .. , . ' ' ':!\P ' f-u $ I " 6 / ,,; 9 ~ •..• ! 0 ~ •se-z ·:,c I dr.'f~i ... d, -~--. : : ~ ~ i ~ J~ _. I . v ~, .. ., .'. . .. ,,___ , , •v -; cc :--; ., fi> , r i ···I· · ~ · ... !'~" a· '~. ·'' I f,w;c ' • f-...... ". 4' , .1 , , ...... , \. ·,i / ~~ r ·* :~i7'/ 11 . ...--.. ""' 1 1 I• '' "I ·1· SP-11 :.·:I· 1 ,~.:.::.:: ...... , ' ,.J . ,,1, ... f, ~-2 -c, ' 12 • 1· 'i r .··r"."I_ j ...... I ,'? ,i,!·,.~. TRACT E ' ' I ... o. -/ ,, V, ' ..... " ·•--1., .-I I._·: __ J. . :JI. . _ '0 \ '~ ....,:J:td./'..-" "'..; : ·",.,_::., , ·. ·· sTOR"' VAULT ' : f IJ ]1 ,'."·· ..-.•<( , ?~" 7 • /": t-· 10 , 1t ! : ~ \,y· .. ·:,o_J. ..... '? .! , , ~-,.: ,', , f{',.~,.f~ .·· ... '-, .· , ~~~ \ • : f :· r;: ,, ______ --=:·::-·.t'.:2-:?:: \::· i ·~;~~:'..·~"' / -~ ----•-----.--/ ------;~--~ i-~1':' ., r: ~ 8" . { ·· t· ·-~ : NE 2NJf PLACE .j \ ff ~ i ,_\'.\ ;• H (/ ' .. =:, ~, ;;r·~~·~ir'-'~·:"; (PRIV E_ROAO) ·,--•;• ' ' . ' . . ' I ·1 • SP-1 Sampling Number and Approximate Location cf-' a,'\ 0 ~o"'"" ''sf'"" <fo"' 0 50 100 Seale in Feet ;\'l \"t ·\/\., \' '1' I I I I FIGURE 2: SITE PLAN Rosewood Highlands Prel~ry Plat Renton. Washhglon Source: ESM Consulting Engineers. ~N'J'-[: ~~\J\!.'r.'\om,ol.,"\.On>a1omt Dnolo.....,__ lli<lo'°"dl\,t,nCR.-01.1-,i _, ",<,& >;-,1\(Y i,'v <J..,"\ 0 ~ 1,.0,t.\' '('t.:,._"\O ' " <' 0 ,, N Chad Armour, LLC 6SOO 1261h Aven~ SE 8elt.....,.,a, Weahlnglon 96006 "8 ,,; t I £ AgC · Alderwood gravelly sandy loam, 6 to 15 percent slopes Source: http://www.or.nrcs.usda.gov/pnw _ soil/wa_. reports.html ~ NOT TO SCALE il'--------------------------------------------..1 C .g ~r,F;:;l,;:G:;-U;;:R;-;E:"'.3;;-::--;S:;-:0~1;;-L-;::S-;M:;A-;;-;:;:P--------------.....-:C:-oh-a-d:-A-r-m-o-u-r-, _L_L_C ___ ....., '§ Rosewood Highlands Preliminary Plat, 6500 126'" Avenue SE ~ Renton, Washington Bellevue, Washington 98006 <( ____________________ ..__ ________ .....J Assessment Methods Critical Areas Assessment and Delineation Renton, Washington Rosewood Highlands Preliminary Plat ASSESSMENT METHODS Chad Armour reviewed, City of Renton (2005), King County (2007), Department of Natural Resources (DNR. 2007), and National Wetland Inventory (FWS, 2007) maps to assess the nature and relative extent of wetlands and streams mapped on and in the vicinity of the site. We also reviewed the Stream net (2007) database to assess the potential for salmonids to be present on or near the site. After we arrived at the site, we traversed the site to observe the physiography (e.g., depressions and ditches) and plant community arrangement of the site. We also observed the area within 150 feet of the site to look for the presence of critical areas. We used the Routine On-site Determination method detailed in the U.S. Army Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory, 1987) and Washington State Wetlands Identification and Delineation Manual (Ecology, 1997). We identified plant species using the Flora of the Pacific Northwest (Hitchcock and Cronquist, 1973) and A Field Guide to the Common Wetland Plants of Western Washington and Northwestern Oregon (Cooke, 1997). The associated indicator status for each plant species was determined using the National List of Plant Species That Occur in Wetlands: Northwest (Region 91 (Reed, 1988 updated in 1993). We assessed wetlands using the Washinton State Wetland Rating System for Western Washington - Revised (Hruby, 2004). We measured the width and depth of the stream with a steel tape. There is no published method for assessing streams. We referenced City of Renton (Renton, 2005a) regulations to assess applicable critical areas and permitting requirements. Soils were identified using the Soil Survey of King County Area. Washington (Snyder et al., 1973). We marked the location of sampling points with flagging with indelible ink. ESM Consulting Engineers located the flags and Brick Tudor Studios created the maps. Wetland determination rating forms follow. Indicator categories shown on the field data forms are defined as follows: OBL (obligate) FACW (facultative wetland) FAG (facultative) FACU (facultative upland) UPL (upland) NI >99% 67%-99% 34%-66% 1% -33% <1% No Indicator Assi ned A positive or negative sign more specifically defines the regional frequency of occurrence for FACW, FAG, or FACU species. A positive sign(+) indicates a frequency toward the higher end of the category. Conversely, a negative sign(-) indicates a frequency toward the lower end of the category. C:/ESM/RoseNVetland Delineation Report.doc Chad Armour, LLC 02/26/07 Wetland Rating Field Data Forms Map Unit Name AIJ.e<~0c,.R, ~'r+9#7' 5;. ... «t Jo«.~) :eries & Phase) 6 1D lbf-u;. ~f' lop&.!, h :ofile Description Depth Horizon Matrix color Mottle colors Monie abundance 1ches) (Munsell (Munsell size & contrast moist) moist) i A /b'fR.. z}z.., Drainage Class f!,,,IJ, t,vd/ ,-&r,,.._, ~"' Field observati,_ons confirm Cxs) No ma ed e? Texture, concretions, Drawing of soil structure, etc. profile (match descri12tion) :5r&..;JJ /06.. ..... i; s...... (7f'?>o, ) vJe..,t' -vcrj ~d-.l.'j -.~ -fi )) -ii r.,._,e,) ~ ..:J . -__ Jdric Soil Indicators: (check all that apply) /JDv,e... __ Histosol __ Matrix chroma ::; 2 with mottles _. _ Histic Epipedon __ Mg or Fe Concretions --Sulfidic Odor __ High Organic Content in Surface Layer of Sandy Soils __ Aquic Moisture Regime __ Organic Streaking in Sandy Soils __ Reducing Conditions __ Listed on National/Local H ydric Soils List Gleyed or Low-Chroma(=!) matrix Other ( exnlain in remarks) Hvdric soils present? yes ® tionale for decision/Remarks: -·, , etland Determination (circle) , I drophytic vegetation present? yes ~ L, dric soils present? yes Is the sampling point yes G) Wetland hydrology present? ves 0 within a wetland? 0 - tionale/Remarks: 5 /op~ 3°/0 A !,.{).et-Jr e ""' t"' - l'")TES: 5..._.,._pl::5 pi:,1.-.-C J>'l ...._ow~ J~i.,.:," l'le.,;.r a,,..-/ZJf 0 ;5;..~l..,c,,,_I b,e.._k.. +1..0t<JL 11-<-~fr~.,_..,, C,IP!,..-)7 £,.,__,f j'"'"='S~ Vej~fu--/r,, .... rr.~----:5,, 0 .,, ~ dj,(b""~i.,111,.,,,t.,,,) ,:;,-f ~J..-r..,, Sl.bf-'4 &i~k}el1 QJ\/t!?.F~J! w,"t0 tP. 11-,,c.,);.. 1;<~),e: ,j,-f /tn, ... d /,,y,..,_ b)=f<.b-errJ; OCC""-.5$>o ... ..J... b)=..k.. t!V-/r""' w= fl, -fY ce (iz N-'-z.o" .£bk) Revised 4/97 - - ~ ~ap Unit Name ltl&w,_.,.Q. 2,_'""\J,a.llj ;:,~ .. .iy )od>N<1 ,enes & Phase) ~ -fo / ~ p~u-!f ~!Pf= Drainage Class Holl, WGJI .,..J,.,-.,,..,,,.,R_ Field observations confirm ~ No ,· Taxonom (sub rou -) . E,,, -h~ b'-V2> .c...l--r<L f-s d :-ofile Description Depth Horizon Matrix color Mottle colors Mottle abundance Texture, concretions, Drawing of soil 1ches) (Munsell (Munsell size & contrast structure, etc. profile moist) moist) (match descriQtion) 5 --" t!!f 1 > 6. .. Jf. '-/ vJ e..+---\I ~~-I &-fr,.~ t,J\..f 10 I (fi11) __ Jdric Soil Indicators: (check all that apply) ti/A _Histosol --Matrix chroma s 2 with mottles __ Histic Epipedon __ Mg or Fe Concretions --Sulfidic Odor __ High Organic Content in Surface Layer of Sandy Soils __ Aguie Moisture Regime __ Organic Streaking in Sandy Soils __ Reducing Conditions _ Listed on National/Local Hydric Soils List Gleyed or Low-Chroma(=!) matrix Other ( explain in remarks) HYdricsoilsp~n_t? yes ~ ,k +,fG .,-rikv ~ -f--~ ;s.t".u...,-. .uonale for dec1s1on/Remarks: b ..e..,.,.:; Co .J ~ Ct...'1' 2-1) ~ ':);;,1 v-' ,.Je I~ -f1 ll, h I\ ...-d .._f., . -ro ?-'*u.e-, M,1(.,-.~ /i., e. A ,J,.!1,,-t;. '-Wt ;,f 5r~u~ ~ilee.<'d <'-f .shi.,J.,~s 1k-e)-1 f~wii,., .. s, ;;,t ~ <-,J-r <."'L-<---, d ... ~1. ,s VlD fo,.,,~RJ vre,s~., "-: .. etland Determination (circle) U drophytic vegetation present? ({;;) no --, dric soils present? yes~ Is the sampling point yes G) Wetland hvdroloo-v present? · ves no within a wetland? ~ ' - tionale/Remarks: A-1-f(..I •• ..J $pl) {.f. 11) r' c.J ~+-"".;. -}z:, &..., 6~a , 5e,,..:;,e, I,., e. • b-d,ld J.,,e.rt?. J C,'fl'~ ~ -to 'f1,_v, V'-toW~ (ve.0 ,-,; .,( 0,SJ-j-~JI> C{)srr1.:lc,,r ~~-----f0w.5 (jv-. p-e,/L_,.,p+.J.iJ1) TD 1N.-5Dt.<..iL, ' tl....--h (.~ ... J rJ-«-..,..--t co--,.,.~,-+j wof-e,,-Q ,-. <!<"' a.rf,-f,L., .... I s.,,,J, Revised 4/97 ' APPENDIX B j- I cl'.). ( +,.o PARCEL C o-' ,, • "' PARCEL G • .v' ,• -·' "',;., ""~"" 47 • ·---... :;:::~:~L~~ .. ~~~..:j,o;;;;;Zt:~ .. :-.:----->··--··-·----•----'1"9'pi'1;1-:_~-.. -·< ·-.,.,_ I l -~·L~~n""m"'"'"'"'f • ~ 1, ' '"''"i!!, •, fj -•• , • ~ • ... o• I 40< I ~---• =:_-,~-~-:!.•"u .... ~,M.<. """-• ,, I \l1J#~~---1 {"-'f I " ) _ __J I • 40" l,/,,. . f TRACT .,._ y/ ~o· I ,o· I ,o· I ~·J9· I -,ml 20 J.U-f?i / 1,.\ ., I' ,. i,." :~.._,_ . ....:7,B:. --. -· . --~ , i-11 "O\ ):.:: ..... :::;.~~::l]cl,_;:::,ts-;i~:/,.~ -74· ' I J' I ' 1 \1 ---. ---·::::•:~-~--, 1·--.,,..f-·--J. ,. ! 72' "' , , • ~ .... -ff _, , ··---------[ 1• i' s J ?! ~ • / _, I '~I ~·, ' 010' • .. -_.:_J' : 5 ' , / / , ........ -_ -· j ·\ p . I "i::.-::::,1;!. t:• -------s,·----~,. ... ~:-=---·-·; , . , 0 i ' , ·-"""'°----· ,s· ••· -·· ·1 · ! ·6 ....:.· --· -a"il' • • r' o=-1 o , ' LB / \ jf'I ._ TAX -·------J ,:;-;,;ii .,. 1'' /. PA 51 :i!10-0 .. ,. \J~ --"""~ l. I t ...... · "/ --;r--' ; ftlw,"'""1 r,. .. /, I '_j, V-7]''.l- ,.I' ,"' \ ,• ~},; ij i r J _ -· ---L___ ,-~L..::: ___ _j,../ ~ ~ ; l.!~.·---~i;--l ----45' ) ./ 69" . ' 'f' ''\! '5 ·i J5' 45' 1•·'1'1° ,.. t",I ~---·····-< ~~~,, ~. .. -. i_ ..... i'-. ,.,,-----i: 1 : PARCEL H :· -.,"---.,, r ~~ . . ' ' . " (J#JltP 1,,I TO m?' -=·· ~·--,, / (o&,c.e,1 -----·----T .. ----·····-·· ··----.. -------·-··- Ill i www.esmc::lvil.com AMERICAN CLASSIC HOMES, LLC UNION PROPERTY DOWNSTREAM ANALYSIS --· --·, T-· w .. vi.esmcfvi1.com c;.ot~•""II ·--,!Ob...O.,,., ...... _ \ ..... --. .... _....,._ c,,,11, -·-· --~-" -......... ......... .,. __ AMERICAN CLASSIC HOMES, LLC UNION PROPERTY OOWNSTRl:Mf ANALYSIS -----··---:-----,~ APPENDIXC Plat of Typpoll Detention Cales E:SM Preliminary Detention Cales Plat of Union ESM CONSUL TING ENGINEERS, LL C 20021 120th Avenue NE, Suite 103 Bothell, WA 98011-8203 (425) 415--6144 FAX: (425) 415-0924 Location I Parcels: "The site is located at 230 Union Avenue Northeast, Renton *NW 114 of Sect. 15, Twn. 23, Rge 05 East W.M *Parcel numbers are: Jurisdictions: City of Renton Codes: 51821 0-0068 518210--0069 518210-0073 518210-0079 518210-0081 518210-0085 Runoff Control! -2005 KCSWDM Water Quality control -2005 KCSWDM. Site Information: *Zoned R-10 (Residential) *Site area is 191,204 square feet= 4 39 AC ·Soils areAlerwood Gravelly Sandy Loam, 6 to 15 % (AgC). "PerKCSWDM soils are classifeid as Alderwood = C, Till "Existing use is single-family residences *NE 2nd Pl is included in site boundary *There is one drainage basin on the site. *Area unable to be collected and assumed not impacted -Weiand tract and associated buffer area = DATE: 8/24/06 JOB NO. 1352-001--006 COMP B' RCL CHKDBY: -191;~~?J~tsf = :. }'~12$ 2!.l: sf = <t·]a',622'.66! sf = Developable Area= 167,586 75 sf= 385 ac "Areas are obtained by AutoCAD. *Assumed all off-site flows are colected and bypassed around/through development *King County Flow control map specifies area around the City of Renton as Conservation FC Areas. "The City of Renton specifies Conservation FC Areas Detetnion Requirements: 3[7/2007 Match durations for 50% 2-yr through 50-year and historic 2-yr and 10-yr peaks. SITE *Assume historic site conditions (Forested) PRE-DEV: ESM Job#: 1313-001-006 1 of 3 Calced by: RCL ' i f ' Plat ofTyppolt Pre-Total: Forested Detention Cales 3 85 ac 167,586.75 sf = Total 3(7/2007 3.85 ac 3.85 ac .DEV:·--------------------------------------------------------- Site: ;f\rt~f,;§!!6;75 sf= *Number of Lots = ·Lot impervious (per city code) = *lot area= *impervious width of NE 2nd PL = *impervious length of NE 2nd PL = *Main public road impervious width = *Main public road impervious length = *Imperviousness width of tracks A & C = *Imperviousness length of tracks A & C = 'Imperviousness width of tracks B & D = 'Imperviousness length of tracks B & D = *Number of driveway to lots in ROW = *Size of driveway in ROW (20x1) = ROW: Impervious: Lots/Tracts: Impervious: Dev-Total: Impervious: Pervious: Roads= Driveways= Walks/Curbs (in with roads)= Site-ROW= Homes= Driveways (in with homes)= Asphalt in Private Drive Tracts = Detention Imperviousness (roads) = Roads Drvieways Walks/curbs Homes Total Area= Grass= {total site area -impervious) 3 85 ac :q&,ic:ch '· If • If If ,ill JI ; If . ······'" .c• ... •. If ~~i~\i~~;~I~~: ~ch 0.00 ac 43,669 00 sf 300.00 sf ';:·'t•'.~1,fc::CP:06 sf 0.00 ac 83,37075 sf 0 00 sf jf;;;jl),9~ sf ·• •t350•00 sf 385 ac = = = Sub-Total = = = = Sub-Total = = = = Total = Total Grand Total 1 00 ac 0 01 ac 0.00 ac 1 01 ac 1 91 ac O 00 ac 0.00 ac 0.03 ac 1 94 ac 1 03 ac 0 01 ac 000 ac 1.91 ac 2 95 ac 0.90 ac 0.90 ac 3.85 ac DETENTION DESIGN: ---------. -------------------------------------- *Pregram used is KCRTS *The detntion facility will be a vault ESM Job#: 1313-001-006 2 of 3 Calced by: RCL r i L i I Plat of Typpolt Detention Cales *Per Water Quality Assessment for Washington Map, the srte is not phosphorus control. *Site is within Sea-Tac 1.0. Minimum live storage elevation = Maximum live storage elevation = Distance from top of live surface to Finish Grade = Total live storage depth = Required surface area = Proposed surface area = Factor of safety = Bottom miface elevation = Bottom oriface diameter= Second oriface distance = Second oriface elevation = Second oriface diameter= Third oriface distance = Third oriface elevation = Third oriface diamter = : .. :::":iE.t::~I :~,,~f;~cr sf 2Ui\,j:j,;,i:;; ft sf #DIV/0! 384 ft inches 386 ft iWO'inches ~:;'J';:r:f:';';Q ft 386 ft inches 31712007 0 " = 0 = 0 " WATERQUALITYDESIGN: --------------------------- "Per the WWHM Version 3.0 On-Line BMP: Off-Line BMP: 24-hour Volume= Standard Flow Rate = 15 Minute Flow Rate = Standard Flaw Rate = 15 Minute Flow Rate = ESM Job #: 1313--001-006 3 of3 cfs cfs Calced by: RCL Flow Fiequency Analysis Time Ser~es File:pre.tsf Project Location:Sea-Tac ---Annual Peak Elow Rates--- flow Rate Rank Time of Peak (CFS) 0.243 2 2/09/01 18: 00 0.066 7 1/06/02 3:00 0 .. 180 4 2/28/03 3:00 0.006 8 3/24 /04 20:00 0 .107 6 1/05/05 8:00 0 .18 7 3 1/18/06 21:00 0.157 5 11/24/06 4:00 0 .. 311 1 1/09/08 9:00 Computed Peaks I 5 + ,vi. ./--e-vvc-l ,;,"le -::: o. /07 o.os-4ch o, 2~ 'is"-o.os-1....::: .~s- -----Flow Frequency Analysis------- -Peaks Rank Return Prob (CFS) Pe,iod 0.311 1 100 .. 00 0 .. 243 2 25.00 0.187 3 10.00 0.180 4 5.00 0.157 5 3 .. 00 0 .107 6 2 .. 00 0.066 7 1.30 0. 006 8 1 .10 0 .288 50 .. 00 0.990 0.960 0 .. 900 0.800 0 .. 667 0 .. 500 0.231 0. 091 0 .. 980 ,. /ev.,..l,-,:-~ C S<'(' V ~ 0. U$Ck t ( oo;-11) ;; %, (,;) :.-7.7> F+ { D, o7i cts. o. u-n .. Retention/Detention Facility Type of Facility: Facility Length: Facility Width: Facility Ar.ea: Effective Storage Depth: Stage O Elevation: Storage Volume: Riser Bead: Rise:r Diametez:: NumbeI of orifices: Detention Vault 10100 ft 108 .00 ft 10908. sq .. 5.00 ;'t 100 .00 ft 54540 .. cu .. 5 .oo ft ft ft 18. 00 ir.ches 3 Pipe Orifice # Height (ft) DiameteI (in) Full Head Jischarge (CFS) 0.069 0 126 0 .. 04 5 Diameter (in) 1 0 .. 00 2 3 .. 00 3 4.45 Top Notch Weir: None Outflow Rating Curve: None 1. 06 1. 81 1.50 4 .. 0 4 .. 0 Stage Elevation Storage Discharge {ft) (ft) {cu .. ft) (ac-ft) (cfs) o .. 00 100 .. 00 0 .. 0 .. 000 0 .. 000 0.01 100 .. 01 109. 0. 003 0.003 0.02 100 02 218 .. 0. 005 0 .. 005 0.03 100 .. 03 32 7 0 008 0 .. 006 0 .. 04 100 .. 04 436 .. 0 .010 0 .. 006 0.06 100 .. 06 655 .. D .. 015 0 .. 007 0.07 100.07 764 0 .. 018 0.008 0.08 100.08 8 73 .. 0 020 0.009 0.09 100.09 982 .. 0 .. 023 0.009 o .19 100.19 2073. 0 . 046 0 .. 013 0 .. 29 100.29 3163. 0 073 0. 016 0 .. 39 100 .. 39 4251 .. 0 098 0.019 0. 4 9 100.49 534 5. 0 .123 0 .. 021 0 .. 59 100.59 6436 0 .148 0.024 0 .69 100 .. 69 7 52 7 0 .173 0 .. 025 0 .79 100 .. 7 9 861 7 .. 0 .. 198 o .. 021 0. 89 100 .. 89 9708. 0 .. 223 0.029 0 .99 100.99 10799 .. 0.248 0 .. 030 1 .09 101 .. 09 11890 .. 0 .. 2 73 0 .. 032 1.19 101 .. 19 12981. 0. 298 0 .. 033 1..29 101.29 14071 .. D 323 0 .. 035 1..39 101 39 15162. 0. 348 0 .. 036 1.49 101..49 16253 D 373 0 .. 037 1..59 101.59 1734 4 .. 0 . 398 0 .. 039 1..69 101..69 18435 ... D . 423 0.040 1.. 79 101. 79 19525 .. D .. 448 0 .. 041 1.89 101..89 20616. 0 .. 4 73 0 .. 042 1.. 99 101. 99 21707. D 498 0.043 2. 09 102.09 22798. 0 523 0.044 2.19 102 .19 23889 .. 0. 548 0 .. 045 2 .. 29 102.29 24979 0. 573 0. 04 6 Fer colation (cfs) 0.00 0.00 0.00 0 .. 00 0 .. 00 0.00 0.00 0.00 0.00 0 .. 00 0 .. 00 0 .. 00 0.00 0 .. 00 0.00 0.00 0.00 0.00 0 .. 00 0 .. 00 0.00 0 .. 00 0 .. DO 0.00 0 00 0 .. 00 0 .. 00 0 .. 00 0.00 0 .. 00 0 .. 00 ! r ' 2 .. 39 102 .. 39 26070. 0 .. 598 0. 04 7 0 .. 00 2 .. 49 102 .. 49 2 7161.. 0 .. 624 0.048 0.00 2.59 102 . 59 28252 .. 0 64 9 0.049 0 .. 00 2.69 102 .. 69 29343. 0. 674 0.050 0 00 2.79 102 .. 7 9 30433. 0 .699 0.051 0.00 2.89 102.89 31524. o. 724 0 .. 052 0.00 2.99 102.99 32 615 .. 0 .. 749 0 .. 053 0.00 3.00 103.00 32724 0 . 7 51 0 .. 053 0 .. 00 3 .02 103.02 32942 .. 0 . 7 56 0.054 0.00 3.04 103.04 33160 .. 0 .761 0 .. 056 0 .. 00 3.06 103.06 33378 o .. 766 0. 060 0.00 3.08 103 .. 08 33597 .. 0 . 771 0 .065 0 00 3.09 103.09 33706. 0 .. 774 0 .. 071 0.00 3.11 103 .11 33924. 0 .. 779 0.078 o .. oo 3 .. 13 103 .. 13 34142. o. 784 0.086 0 .. 00 3 .. 15 103 .. 15 34360. 0 .789 0.089 0 .. 00 3.17 103 .. 17 34578 0 . 794 D. 091 0 .. 00 3.27 103.27 35669 .. 0 . 819 0 .. 102 o .. oo 3.37 103.37 36760. o. 844 0.110 0 .. 00 3.47 103 .. 4 7 37851 0 869 0 .118 0 .. 00 3.57 103.57 38942 .. 0.894 0.125 0 .. 00 3 .. 67 103.67 40032 .. 0.919 0 .. 132 0 .. 00 i 3. 77 103 .. 77 41123 0.944 0.138 0 .. 00 ' 3. 87 103.87 42214. 0 .969 0 .. 143 0.00 I i 3 .. 97 103.97 43305. 0. 994 0 .. 149 0.00 L 4. 07 104..07 44396. 1.019 0.154 0.00 I 4 .1 7 104.17 45486 .. l. 044 0 .159 0.00 i 4 .. 2 7 104 .. 2 7 465 77 . 1.069 0 .164 0.00 4.37 104 . 3 7 47668 l.. 094 0 .. 168 0.00 4 . 4 5 104 .. 45 48541 .. 1. 114 0 .172 0.00 4. 4 7 104 .. 4 7 48759 .. 1.119 0 .. 173 0.00 4 .. 48 104.48 48868 .. 1 .. 122 0 .. 1 75 0.00 4 .. 50 104 .. 50 49086. 1 127 0 178 0.00 4 .. 51 104 .. 51 49195. 1.129 0 .. 182 0.00 4 .. 53 104.53 49413. 1. 134 0.187 0 .. 00 4 .. 54 104 . 54 49522 1.137 0.193 0 .. 00 4.56 104.56 49740. l 142 0.197 0.00 4.57 104.57 49850. 1.144 0.199 0 .00 4. 67 104. 6 7 50940. 1.169 0 .. 211 0 .. 00 4. 77 104 . 77 52031 1 .194 0.221 0 .. 00 4 87 104 .. 87 53122 .. l. 220 0.230 0.00 4 .. 97 104 .. 97 54213 .. 1 . 245 0 .. 238 0.00 5.00 105.00 54540. 1 252 0 .. 240 0.00 5.10 105.10 55631 . 1.277 0 .. 710 0.00 5 .. 20 105.20 56722. 1 302 1.560 0.00 5 .. 30 105.30 5 7812 .. 1 327 2 .. 660 0.00 5 .. 40 105.40 58903. 1 . 352 3. 960 0 .. 00 5.50 105 .. 50 59994 1 . 377 5 . 440 0.00 5.60 105.60 61085. l . 402 6 870 0.00 5 .. 70 105. 70 6217 6 .. L 427 7 .410 0 . 00 5.80 105.80 632 6 6 .. 1 452 7 .910 0. 00 5.90 105.90 6435 7 1 . 4 77 8 .370 0 .00 6 00 106 .. 00 65448. 1 .502 8 . 810 0 .00 6 .. 10 106 .. 10 66539. l 528 9.240 0 .00 6 .. 20 106 .. 20 67630. 1 .553 9. 640 0 .00 6 .30 106 30 68 720 . 1 .578 10.020 0 .00 6 .40 106 4 0 69811 1 .603 10.400 0. 00 6 .. 50 106 .. 50 70902 .. 1.628 6 .. 60 106 .. 60 71993 1. 653 6 .. 70 106. 70 73084 .. L 678 6.80 106 .. 80 74174, 1. 703 6.90 106 90 7 52 65. 1. 728 7. 00 107.00 76356 .. 1. 753 Hyd Inflow Outflow Peak Taiget Cale Stage Elev l l. 58 0.31 o. 8 7 5.12 105.12 2 0.80 ******* 0.24 4.9) 104 .97 3 1.10 ******* 0 .. 17 4.34 :04 .. 34 4 o .. 95 ***'**** 0.16 4.29 104. 29 5 0 .. 85 ******* 0.12 3.51 103 . 51 6 0 .. 90 ******* 0.06 3.04 103 . 04 7 0 .. 67 ******* 0 .. 05 2.96 102 .. 96 8 0.75 ******* 0 .. 04 2.12 102 ,2.2 Route Time Se:ries thiough Facility Inflow Time Series File:dev ts£ Outflow Time Series File:rdout Inflow/Outflow Analysis Peak Inflow Discharge: Peak Outflow Discharge: Peak Reservoir Stage: Peak Reservoir Elev: 1. 58 0. 8 7 5 5 .. 12 105 12 CFS CFS ft ft at at Peak Reservoir Storage: 55841. Cu-Ft 1 Flow Frequency Analysis Time Series File:rdout .. tsf Project Location:Sea-Tac .282 Ac-Ft 10.750 0 .. 00 11.100 0.00 1L440 0.00 11.. 7 60 o.oo 12.080 o.oo 12.390 0.00 Storage (Cu-Ft) (Ac-Ft) 55841. 1.282 54249 .. 1..245 4 7307 _ 1.086 46788 .. l. 074 38260 .. 0.878 33172 .. 0.762 32294. 0.741 23075. 0.530 6:00 on Jan 9 in YeaI 8 10:00 on Jan 9 in Year 8 ---Annual Peak flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks --Rank Re.tur.n Prob (CF SI (CFS) (ft) Period 0. 238 2 2/09/01 20:00 0.875 5.12 1 100 .. 00 0.990 0.053 7 1/07/02 4:00 0.238 4. 97 2 25.00 0.960 0 .. 165 4 3/06/03 22:00 0. 16) 4 .. 34 3 10 .. 00 0.900 0 .. 044 8 8/26/04 7: 00 0 .165 4.29 4 5.00 0 800 0 .. 056 6 1/08/05 5:00 0 .121 3.51 5 3.00 0 .. 66 7 0.121 5 1/18/06 23:00 0 .056 3 .. 04 6 2.00 o .. 500 0.167 3 11/24/06 8:00 0 . 053 2 .. 96 7 1.30 0 .. 231 0.875 1 1/09/08 10:00 D .044 2 .. 12 8 1.10 0.091 Computed Peaks 0 663 5 .. 09 SO.DO 0. 980 Flow Duration fiorn Time Seiies Fil.e:rdout .tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.003 27856 45.42) 45. 427 54 .. 5 73 o. 546E+OO 0.010 7423 12.105 57 533 42.467 0 . 425E+OO 0.017 6787 11..068 68 601 31.399 0 .311E+OO 0.023 5406 8.816 77 . 41 7 22.583 0 .226E+OO 0.030 5629 9.180 86.597 13.403 0 .134E+OO 0.037 3529 5.755 92.352 7. 648 0 .. l65E-01 0 .. 043 194 7 3.175 95 .. 527 4 .. 4 73 0 .. 447E-01 0.050 1753 2.859 98.386 1 614 0 .. 161E-01 0.057 600 0.978 99.364 0 .. 636 0.636E-02 0 .. 064 31 0.051 99. 415 0. 585 0.585E-02 0 .. 070 15 0.024 99.439 0 . 561 0.561E-02 0. 077 14 0.023 99.462 0 .538 0.538E-02 0 .. 084 8 0.013 99.475 0 525 0.525E-02 0.090 25 0 .041 99.516 0 484 0.484£-02 0.097 45 0.073 99. 58 9 0 .. 411 0 .. 411E-02 0 .. 104 34 0 055 99.644 0 .356 0.356E-02 0.110 32 0.052 99.697 0 .. 303 0 .. 303E-02 0.117 28 0.046 99. 742 0.258 0 258E-02 0 .. 124 28 0.046 99.788 0 .. 212 0.212E-02 0.130 16 0.026 99.814 C .. 186 0 l86E-02 0 .137 12 0.020 99 .. 834 0 .. 166 0. l 66E-D2 0 .. 14 4 16 0.026 99 .. 860 0. 14 0 0.140E-02 0.150 14 0.023 99 .. 883 0. 117 0 .11 7E-02 0 .. 15 7 14 0.023 99 905 0 .. 095 0.946E-03 0.164 17 0 028 99.933 0 . 067 0.669£-03 0.170 22 0 .. 036 99 .. 969 0 031 0.310E-03 0.177 3 0 .. 005 99 .. 974 0 . 026 0 .. 261E-03 0.184 0 0.000 99.974 0.026 0.261E-03 0.190 0 0.000 99 .. 974 0.026 0.261E-03 0.197 1 0.002 99.976 0' 024 0 .. 245E-03 0.204 2 0.003 99.979 0 .021 0 .. 212E-03 0 211 1 0.002 99 .. 980 0. 020 0.196E-03 Q.217 2 0.003 99 .984 0,. 016 0.163E-03 0.224 3 0.005 99. 98 9 0 .Oll 0.114E-03 0.231 2 0.003 99 .. 992 0 . 008 0.815E-04 0.237 4 0 .. 007 99. 998 0 .. 002 0.163E-04 Duration Compaiison Anaylsis Base File: pie.tsf New File: i:dout.tsf Cutoff Units: Discharge in CFS -----fraction of Time--------------Check of cutoff Base New %Change Piobability Base 0.054 0.93E-02 0.69E-02 -25. 3 I 0 .. 93E-02 0.054 0.068 0.62E-02 0 .. 57E-02 -8 '' 6 I 0.62E-02 0.068 0 .083 0. 48E-02 0 .. 53E-02 8 4 I 0 48E-02 0.083 0 097 0.37E-02 0. 41E-02 11 '' 6 I 0.37E-02 0.097 0. ll2 0.28E-02 0 .. 29E-02 2 .9 I 0.28E-02 0.112 0 .. 126 0.22E-02 0 .. 20E-02 -9. I 0.22E-02 0.126 0 .. 141 0 15E-02 0.15£-02 2. 2 I 0 .. 15E-02 0 .141 0.155 0 .. lOE-02 0.99E-03 -1 .. 6 I O.lOE-02 0.155 0.170 0.62E-03 0.34E-03 -44 .. 7 I 0.62E-03 0 .170 0.184 0.34E-03 0.26E-03 -23 .. 8 I 0.34E-03 0 .. 184 0.199 0 .. 21E-03 0.24E-03 15 4 I 0.21E-03 0.199 0.213 0 .. 16E-03 O.lSE-03 10 '' 0 I 0. l 6E-03 0.213 0 .228 0. llE-03 0.98E-04 -14. 3 I O. llE-03 0.228 0 .. 242 0.16E-04 0.00E+OO -100 0 I 0.16E-04 0.242 Maximum positive excursion= 0. 001 cfs ( 9 .1%) occurring at 0.081 cfs on the Hase Data:pre.tsf and at 0_088 cfs on the New Data:rdout.tsf Maximum negative excursion= O 011 cfs (-15"9%)° Tolerance------- New %Change 0 .. 052 -3 .. 1 0.058 -15.2 0.090 8. 7 0.103 5.4 0.113 1..3 0.122 -3 .. 2 0.142 0.6 0.155 -0.1 0.164 -3.3 0.170 -7.9 0 .. 207 3.9 0 .. 218 1 9 0.227 -0 .4 0 .. 238 -1 .. 9 occurring ?).t 0 .. 067 cfs on the Base Data:p1:e.tsf and at 0.056 cfs on the New Data:1:dout.tsf