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HomeMy WebLinkAboutMisc~-----------~--········· --······-~····. -··········-·-· .. · 1 PRELIMINARY TECHNICAL INFORMATION REPORT ("TIR") Valley Vue 3106 Talbot Road South Renton, WA Parcel No. 3023059028 Prepared for: RAD Holdings, LLC 6252 167th Ave SE Bellevue, WA 98006 Prepared by: lo A Land Development Advisors, LLC •12865 SE 47th Place -Bellevue, WA 98006 (425) 466-5203 December, 2013 RADX-001 Preliminary Technical Information Report Valley View TABLE OF CONTENTS TIR WORKSHEET .......................................................................................................... I SECTION 1 PROJECT OVERVIEW .............................................................................. 2 Existing Drainage System .................................................................................................... 2 Proposed Drainage System ................................................................................................... 2 SECTION 2 CONDITIONS AND REQUIREMENTS SUMMARY .................................. 4 Core Requirements ............................................................................................................. .4 Special Requirements ........................................................................................................... 5 SECTION 3 OFF-SITE ANALYSIS ................................................................................ 6 Task 1 -Study Area Definition and Maps .............................................................................. 6 Task 2 -Resource Review ................................................................................................... 6 Adopted Basin Plans ...................................................................................................... 6 FEMA Maps ..................................................................................................................... 6 Other Off-Site Analyses .................................................................................................. 6 Sensitive Areas ............................................................................................................... 6 USDA -NRCS Soil Survey Maps...................................................... .. ............. 6 Wetlands Inventory Maps ................................................................................................ 7 Migrating River Studies ................................................................................................... 7 Section 303d Listing .. .. . ... .. . . . . . . . . . ... ... . .. ... ... ... .. . . .. .. . . . . .. ... ... ... ... .. . ..................... 7 Adopted Stormwater Compliance Plans .......................................................................... 7 Task 3 -Field Inspection ..................................................................................................... 7 Task 4 -Drainage System Description And Problem Descriptions................. . ....... 7 Downstream Drainage System Description ..................................................................... 7 Downstream Drainage Problems Requiring Special Attention ......................................... 7 Task 5 -Mitigation of Existing or Potential Problems ............................................................ 8 SECTION 4 -FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ....................................................................................................................... 14 Existing Site Hydrology ...................................................................................................... 14 developed Site Hydrology .................................................................................................. 15 Performance Standards ...................................................................................................... 15 Flow Control System .......................................................................................................... 16 Water Quality System .......................................................................................................... 17 LAND DEVELOPMENT ADVISORS. LLC. December, 2013 • Preliminary Technical Information Report Valley View Wetpool Volume ...................................................................................................... 17 Overflow Analysis .................................................................................................... 17 Riser Pipe ...... 18 SECTION 5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN .............................. 22 SECTION 6 SPECIAL REPORTS AND STUDIES ...................................................... 24 SECTION 7 OTHER PERMITS .................................................................................... 24 SECTION 8 ESC ANALYSIS AND DESIGN ............................................................... 25 SECTION 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ................................................................................................................. 26 SECTION 10 MAINTENANCE AND OPERATIONS MANUAL. .................................. 26 SECTION 11 REFERENCES ...................................................................................... 26 APPENDIX A-Photographs............................... . .......... 27 Photographs .................................................................................................................. 28 APPENDIX B -Supporting Documentation ......................................................................... 30 Section 303d Listing ...................................................................................................... 31 Vault Sketch .................................................................................................................. 32 KCRTS Output .............................................................................................................. 33 Riser Nomograph .......................................................................................................... 38 APPENDIX C -Technical Reports ...................................................................................... 39 FIGURES Figure 1.1 -Vicinity Map.................................................................................. . ...... 3 Figure 3.0 -City Reference Maps.................................................................. . ..... 9 Figure 3.1 -Basin and Downstream Conveyance Map................ . ......... 10 Figure 3.2 -Sensitive Area Map ................................................................ 11 Figure 3.3 -NRCS Map ............................................................................................................ 12 Figure 3.4 -Site Plans .............................................................................................................. 13 Figure 4.1 -Basin Map ............................................................................................................. 19 Figure 4.2 -Rainfall Regions and Regional Scale Factors ........................................................ 20 Figure 4.3 -Precipitation for Mean Annual Storm...................................................... . ..... 21 Figure 5.1 -Catchment Map .................................................................................................... 23 Appendix A Photographs Appendix B Calculations and Technical References Appendix C Technical Reports LAND DEVELOPMENT ADVISORS, LLC . ii December, 2013 Preliminary Technical Information Report Valley View TIR WORKSHEET LAND DEVELOPMENT ADVISORS, LLC. December, 2013 KING COUNTY. WASIIINGTON. SURFACE WATER DESl(iN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Project Owner RAD Holdings, LLC Phone (206) 715-4559 Address 6252 167th Ave SE Bellevue, WA 98006 Project Engineer _Jo_n_N_el_so_n _____ _ Company Land Development Advisors, LLC Phone 425 466 5203 Part 3 TYPE OF PERMIT APPLICATION l1S) Landuse Services @ubdivison V Short Subd. / UPD 0 Building Services M/F / Commerical I SFR D Clearing and Grading 0 Right-of-Way Use 0 Other Part 5 PLAN AND REPORT INFORMATION Technical Information Report Type of Drainage Review ~ / Targeted (circle): Large Site Date (include revision December 2013 dates) Date of Final: Part 6 ADJUSTMENT APPROVALS I Part 2 PROJECT LOCATION AND DESCRIPTION Project Name _V-'--'a"'"ll"'e,_y-'-V'""ie=w'-------- DDES Permit# ---------- Location Township _2_3_N ___ _ Range _ ___c5_E ____ _ Section 30 ------- Site Address 3106 Talbot Road S. Part 4 OTHER REVIEWS AND PERMITS D DFWHPA COE404 DOE Dam Safety FEMA Floodplain COE Wetlands 0 Shoreline Management D Structural RockeryNaulU __ D ESA Section 7 0 0 0 D I!! Other DOE Stormwater Permit Site Improvement Plan (Engr. Plans) Type (circle one) I Full I / Modified I Small Site Date (include revision December 2013 dates) Date of Final: Type (circle one): Standard / Complex I Preapplication / Experimental/ Blanket Description: (include conditions in TIR Section 2) Date of Annroval: 2009 Surface Water Design Manual 1/9/2009 KIN(; COUNTY. WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / !Nol Describe: Start Date: Completion Date: Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan : _N_i_A __ ~--------- Special District Overlays: -'-N"'/A..,_ ____________________ _ Drainage Basin: _B_la_c_k_R_iv_e_r _________ _ Stormwater Requirements: Level 2 Flow Control, Basic Water Quality Part 9 ONSITE AND ADJACENT SENSITIVE AREAS D River/Stream ________ _ D Steep Slope --------- D Lake 0 Erosion Hazard _______ _ lli:I Wetlands Type 2 -----------D Landslide Hazard ______ _ 0 Closed Depression _______ _ 0 Coal Mine Hazard------- D Floodplain-----------0 Seismic Hazard _______ _ 0 Other ___________ _ 0 Habitat Protection ______ _ D ------------ Part 1 O SOILS Soil Type Slopes Erosion Potential Alderwood Till 0%-15% Moderate D High Groundwater Table (within 5 feet) 0 Sole Source Aquifer D Other 0 Seeps/Springs 0 Additional Sheets Attached 2009 Surface Water Design Manual 2 1/9/2009 KING COUNTY, WASll!NGTON, SURFACE WATER DESIGN MANUAi. TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE LIMITATION/ SITE CONSTRAINT ~ Core 2 -Offsite Analysis Level 2 Flow Control ~ Sensitive/Critical Areas Retained in NGPE Tract D SEPA D Other D D Additional Sheets Attached Part 12 TIR SUMMARY SHEET (orovide one TIR Summarv Sheet aer Threshold Discharae Area\ Threshold Discharge Area: (name or descriotion) Site Core Requirements (all 8 apply) Discharae at Natural Location Number of Natural Discharae Locations: 1 Offsite Analysis Level: l_!J/2/3 dated: concurrent Flow Control Level: 1 il.1.Ji 3 or Exemption Number (incl facility summarv sheet\ Small Site BMPs Conveyance System Spill containment located at: Erosion and Sediment Control ESC Site Supervisor: To be determined Contact Phone: After Hours Phone: Maintenance and Operation Responsibility: Private 1 Public I If Private, Maintenance Loo Required: Yes / No Financial Guarantees and Provided: Yes I No Liability Water Quality Type I Basic I/ Sens. Lake / Enhanced Basicm I Bog (include facility summary sheet) or Exemption No. Landscaoe Manaoement Plan: Yes lil'lol Soecial Reauirements las annlicablel Area Specific Drainage Type: CDA / SDO I MDP I BP/ LMP / Shared Fae. II None I Requirements Name: Floodplain/Floodway Delineation Type: Major I Minor / Exemption I None 100-year Base Flood Elevation (or range): Datum: Flood Protection Facilities Describe: Source Control Describe landuse: (comm./industrial landuse) Describe any structural controls: 2009 Surface Water Design Manual l /9/2009 3 KING COUNTY. WASHINGTON. SURFACc: WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Oil Control High-use Site Yes/~ Treatment BMP Maintenance Agreement: Yes IQ§ with whom? Other Draina11e Structures Describe: Combined detention/water quality vault Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION IZJ Clearing Limits ~ Stabilize Exposed Surfaces IBI Cover Measures IZJ Remove and Restore Temporary ESC Facilities IBI Perimeter Protection ~ Clean and Remove All Silt and Debris, Ensure 129 Traffic Area Stabilization Operation of Permanent Facilities 129 Sediment Retention 129 Flag Limits of SAO and open space ~ Surface Water Collection preservation areas 0 Other 0 Dewatering Control 129 Dust Control 0 Flow Control Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facilitv Summarv and Sketch) Flow Control Tvoe/Description Water Quality Type/Description ~ Detention Vault D Biofiltration D Infiltration ~ Wetpool Within Vault D Regional Facility D Media Filtration D Shared Facility D Oil Control D Flow Control D Spill Control BMPs D Flow Control BMPs 0 Other D Other 2009 Surface \Vater Design Manual 4 \/9/2009 KINCi COUl\TY. WASHINGTON. SL"RFACE \\'ATER DESIGN MAl\LAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 15 EASEMENTSfTRACTS Drainage Easement l3f Covenant 0 Native Growth Protection Covenant ~Tract I D Other I Part 16 STRUCTURAL ANALYSIS I Cast in Place Vault I D Retaining Wall · (29< Rockery > 4 High D Structural on Steep Slope D other Part 17 SIGNATURE OF PROFESSIONAL ENGINEER 1 1. or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowled,ge th( i~for'.1:atioQ provided here is accurate. _...\•[\ I 1 • 1 ' . t 1· ")D\ 1· 7 I c. / · "--12115113 er' I \ \ I f\..\ ) . ' I i ---l ) · Signed/Date 2009 Surface Water Design Manual 5 Preliminary Technical Information Report SECTION 1 PROJECT OVERVIEW Valley View The 2.29 acre site is located in the southerly portion of Renton at 3106 Talbot Road S. and is part of the Black River Basin. See Figure 1.1 -Vicinity Map. Current uses include 2 single family residences in the westerly two-thirds of the site with a scattering of evergreen and deciduous trees. The easterly third of the site is undeveloped and forested with a Type 2 wetland in the far eastern portion of the site. This wetland is part of a larger wetland extending offsite to the east and south. Existing slopes on the site range from 0%-15%, averaging approximately 6%. Site soils are mapped as the Alderwood (AgC) series by the City and the NRCS Web Soil Service as shown on Figure 3.3. EXISTING DRAINAGE SYSTEM Runoff from the site is split with approximately the easterly 150' draining overland towards the wetland along the east boundary. The remainder of the site sheet flows in a westerly direction ultimately entering the swale along the east side of Talbot Road. Flows continue southerly in the roadside drainage system approximately 250' where they turn and flow west through a 21" culvert to the valley floor and Springbrook Creek. Additional details can be found in the Offsite Analysis Section. PROPOSED DRAINAGE SYSTEM Two areas of the site will not be disturbed including any drainage associated with the existing use: the easterly portion of the site with the wetland and buffer together with the existing home nearest Talbot Road. An appropriately sized conveyance system will be designed and constructed to collect the developed on-site runoff from the remainder of the onsite areas as well as the offsite access tracts. The runoff will drain into a detention vault in the westerly portion of the site that will discharge to the existing conveyance system on the east side of Talbot Road. Basic water quality treatment will be provided by "dead" storage within the vault. LAND DEVELOPMENT ADVISORS, LLC. 2 December, 2013 Preliminary Technical Information Report Valley View Figure 1.1 -Vicinity Map LAND DEVELOPMENT ADVISORS, LLC. 3 December, 2013 .J''.:i SJ lf.:'.' . Ch•.r·:::1 c 1'1 or n~i-u· P·1l--li, r~1,~1~. r..-, :11 • '.:iiL·,:>r lfoiliir ilSlllO H,!!llor· SITE *' '··. ··i, ••• , l i .. ,,,.,,. l:l,1 tJII '" D'r. D,n1el O Brie·, f, DDS. MSC "' I SEC. 30, TWP. 23 N,. RGE. 5E, WM. DA Planning. Engineering, ProJect Management Land Development Advisors LLC 12865 SE 47th Place Bellevue. WA 98006 425-466·5203 I' •Jl i S1 ':,', ,., .. ,,,I.,,,. 11.rll('riGill! C!,J:~!-iit H1w1c:; H1:,1lt';l,1!c ·i ',. 71:,t\1 SI SE Ptlro·dsk:,· Rel ~--Sp· r-;i ~If'< ')h:ir:;:;in~ c,:·,:,:- OWN. BY: DATE. JWN 12/15/13 VICINITY MAP VALLEYVIEW JOB NO. RADX001 ~---------+---------+---------~ CHKD. BY: SCALE: J. NELSON NO SCALE FIG. 1.1 Preliminary Technical Information Report Valley View SECTION 2 CONDITIONS AND REQUIREMENTS SUMMARY The drainage design will be in accordance with the 2009 King County Surface Water Design Manual ("KCSWDM") as amended by the City of Renton. The City amendment outlines specific core and special requirements which must be addressed. The following is a list of those requirements and a description of how each is addressed. CORE REQUIREMENTS Core Requirement #1: Discharge at the Natural Location Runoff from the proposed onsite improvements will be discharged at the existing location near the southwest corner of the site. Core Requirement #2: Offsite Analysis An upstream and downstream analysis has been completed for the project. Please refer to the Offsite Analysis Section for a complete description. Core Requirement #3: Flow Control Level 2 flow control will be provided for runoff from the proposed improvements. Core Requirement #4: Conveyance System Conveyance system sizing is addressed in Section 5 of this report. Core Requirement #5: Erosion and Sediment Control A Temporary Erosion and Sediment Control plan will be prepared with the final construction plans in order to prevent, to the maximum extent possible, the transport of sediment to downstream drainage systems, water resources and adjacent properties. BMP measures anticipated include clearing limit delineation, cover measures (straw, plastic, etc.), traffic area stabilization (rock construction entrance) and perimeter protection (silt fencing). Core Requirement #6: Maintenance and Operations Operations and maintenance of this system will be performed by the City. Core Requirement #7: Financial Guarantees and Liability Appropriate bonds and insurance will be provided prior to project approval. Core Requirement #8: Water Quality Basic water quality requirements apply to this project. LAND DEVELOPMENT ADVISORS, LLC. 4 December, 2013 Preliminary Technical Information Report SPECIAL REQUIREMENTS Special Requirement #1: Other Adopted Area-Specific Requirements None known. Critical Drainage Areas None known. Master Drainage Plan Not applicable. Basin Plans None known. Lake Management Plans Not applicable. Shared Facility Drainage Plans Not applicable. Special Requirement #2: Flood Hazard Delineation The project area does not fall within a flood hazard area. Special Requirement #3: Flood Protection Facilities Valley View There are currently no flood protection facilities onsite or near the site. Flood protection facilities will not need to be implemented as a result of the proposed development. Special Requirement #4: Source Controls Not applicable. This project is not a commercial, industrial, multifamily or a redevelopment of a commercial, industrial or multifamily project. Special Requirement #5: Oil Control Not applicable. This project is not a commercial or industrial site. LAND DEVELOPMENT ADVISORS, LLC. 5 December, 2013 Preliminary Technical Information Report SECTION 3 OFF-SITE ANALYSIS Valley View This section has been prepared in support of a Preliminary Plat application for the subject property. The report identifies the tributary basin areas upstream of the Project site, and evaluates downstream drainage systems. The intent of this section is to demonstrate that the proposed Project will not aggravate existing problems nor create new drainage problems. TASK 1 • STUDY AREA DEFINITION AND MAPS The area under consideration is shown on Figure 3.1 -Basin and Downstream Conveyance Map. City reference mapping is included on Figure 3.0 -City References. Upstream Basin Description From available topographic information augmented by visual observations of the adjoining areas, there are no appreciable offsite areas that are tributary to the site. TASK 2 · RESOURCE REVIEW Documents reviewed for existing and/or potential drainage problems, and the findings of each, are listed below: Adopted Basin Plans No adopted basin plans were found for the study area. FEMAMaps FEMA maps were consulted and the site was not located within a designated flood plain. Other Off-Site Analyses No other downstream analyses were reviewed for the area. Sensitive Areas A Type 2 wetland has been identified on the east portion of the site. Refer to the Appendix for the report. The site is not within any mapped areas on the City's Groundwater Protection Area mapping, wetlands inventory, erosion or landslide hazard mapping. Refer to Figure 3.2 -Sensitive Area Map. USDA· NRCS Soil Survey Maps The NRCS Soil Survey and the City's mapping indicate the site soils belong to the Alderwood series. Please refer to Figure 3.3. The onsite soils will be modeled as type C soils. LAND DEVELOPMENT ADVISORS, LLC. 6 December, 2013 Preliminary Technical Information Report Valley View Wetlands Inventory Maps There onsite wetland has not been mapped by the City or County. Figure 3.2 -Sensitive Area Map Migrating River Studies There are no studies on or near the site. Section 303d Listing Lake Washington is a 303d listed water body. Refer to the complete listing in Appendix B. Adopted Stormwater Compliance Plans None known. TASK 3-FIELD INSPECTION The field inspection was completed November 12, 2013. Refer to Figure 3.1 -Downstream Conveyance Map and Appendix A for photographs. TASK 4-DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS Downstream Drainage System Description Runoff from the site is split with approximately the easterly 150' draining overland towards the wetland along the east boundary. There are no issues with this flowpath. The remainder of the site sheet flows in a westerly direction ultimately entering the swale along the east side of Talbot Road. Flows continue southerly in swales and ditches and enter a 12" concrete pipe that continues southerly approximately 95' where they turn and flow west through a 12" pipe to a catchbasin on the west side of Talbot Road. Additional flows enter at this location from the north and south. The outgoing pipe is a 21" concrete that is on private property and outlets at the valley floor and Springbrook Creek. There were no significant drainage problems observed during our site visit; however, minor maintenance is in order for culvert inlets along the downstream path. Downstream Drainage Problems Requiring Special Attention Three problem areas are identified for investigation. The definition of each has been excerpted from the 2009 Drainage Manual. Type 1 problems are: Conveyance system nuisance problem means a flooding or erosion problem that does not constitute a severe flooding problem or severe erosion problem and that results from the overflow of a constructed conveyance system for runoff events less than or equal to a 10-ycar event. Examples include inundation of a shoulder or lane of a roadway, ovedlows colkcting in yards or pastures. shallow flows across driveways. minor flooding of crawl spaces or unheated garages/outbuildings, and minor erosion. LAND DEVELOPMENT ADVISORS, LLC. 7 December, 2013 Preliminary Technical Information Report Valley View Type 2 problems are: Severe erosion problenz means then: is an open drainage feature \vith evidence of or potential for erosion/incision suflicient to pose a sedimentation hazard to do\vnstrcam conveyance systems or pose a landslide hazard by undercutting adjacent slopes. Severe erosion problems do not include roadway shoulder rilling or minor ditch erosion. Finally, there are 2 elements of Type 3, Severe Flooding Problems: Severe building flooding problem means there is flooding of the finished floor area6 of a habitable building, 7 or the electrical/heating system of a habitable building for runoff events less than or equal to a 100-year event. Examples include flooding of finished floors of homes and commercial or industrial buildings, or flooding of electrical1heating system components in the crawl space or garage ofa home. Severe roadway flooding problem means there is flooding over all lanes of a roadway, 8 or a sole access drivewav9 is severely impacted, for runoff events less than or equal to the 100-year event. A severely impacted sole access driveway is one in which flooding overtops a culverted section of the driveway, posing a threat of washout or unsafe access conditions due to indiscernible driveway edges, or flooding is deeper than 6 inches on the driveway, posing a severe impediment to emergency access. The downstream drainage system does not exhibit any of these potential problems. TASK 5-MITIGATION OF EXISTING OR POTENTIAL PROBLEMS Onsite detention will be provided to a Level 2 flow control standard. This standard is typically adopted to mitigate stream erosion and is warranted so that downstream erosion is not exacerbated. LAND DEVELOPMENT ADVISORS, LLC. 8 December, 2013 Preliminary Technical Information Report Valley View Figure 3.0 -City Reference Maps LAND DEVELOPMENT ADVISORS, LLC. 9 December, 2013 "" c:::J AQulfw Pm:ttel,on An!A /'one 1 f,lodi"led ,-.. -.. _ .. ~ Renton C,ty Lim 15 SEC. 30, TWP. 23 N,. RGE. 5E, W.M. Tu ""o.o • SITE PUS DA Planning E ng1neenng, Project Management Land Development Advisors, LL C 12865 SE 4 7th Place Bellevue. WA 98006 425 -466-5203 -'SC """ ,.,. """ ... No AQC Ho ... ... " ,.,. Amil ..... ,.,. ···~ CITY SOIL SURVEY VALLEY VIEW OWN. BY: DATE: JOB NO. JWN 12/15/13 RAOX001 ~ -:---i CHKD. BY: I SCALE: J. NELSON NO SCALE FIG . 3 .0 • ,,. c .... t-,.. .~ ... • 'f<'Y'"J"" .... ""1" Cedar Valley Sole Source Aquifer PraJ.et Rev iew Area WellfielCS Captvre Zonu Aquifer Protection Arn Zones SEC. 30, TWP. 23 N,. RGE. 5E, W.M. DA Planning Engineering, Project Management Land Oevelopmenl Advisors. LLC 12865 SE 47th Place Bellevue WA 98006 4 25-4 66-5203 GROUNDWATER PROTECTION AREAS VALLEY VIEW OWN. BY: DATE: I JOB NO. JWN 12/15/13 RADX001 CHKO. BY: SCA LE: T J. NELSON NO SCALE FIG. 3 .0 Flow C o ntrol Standards Peak Rale Flow Conlrol Standard (Exost,ng Site Cond1t1ons) Flow Conlrol Duration Standard (E)(1sting Sile Conditions) Flow Conlrol Duralion Standard (Forested Condil1ons) ~··-··· i. ..... i Renton City L1m1ts [.:·J Poten11a1 An nexation Area SEC. 30, TWP. 23 N ,. RGE. SE, WM. DA Planning Engineering. Pro1ect Managem ent Land Development Advisors , LLC 12865 SE 4 71h Place Bellesue. WA 98006 425 466-5203 FLOW CONTROL APPL/CATIONS VALLEY VIEW OWN. BY: JWN CHKD. BY: J. NELS ON DATE: 12/15/13 S CALE: N O SCALE JOB NO. RADX001 FIG. 3 .0 \ :-··-.. _ .. .; Renton City Li mits :-.. - .. : Potential Annexation Area ---~ Basin s Black River Du amish Lake Washington East Lake Washington West Lower Cedar River May Creek Soos Creek SEC. 30, T W P. 23 N ,. RGE. SE , W.M. DA Planning E ng me en ng , P roJect Management Land Oev elopm enl Advisors. LL C 12865 S E 4 7th Place Bellevue . W A 98006 4 25 -4 66-5203 '."'!'-..-. ···-·----..... --, l ..•... l D RA INAGE BASINS VA LLEY VIEW OWN. BY: JWN DATE: 12/15/13 C HKO. BY: S CALE: J. N EL S ON I N O SCAL E JOB NO. RAD X00 1 F IG. 3 .0 Preliminary Technical Information Report Valley View Figure 3.1 -Basin and Downstream Conveyance Map LAND DEVELOPMENT ADVISORS. LLC. 10 December, 2013 I I I I I :::;:: ,:: l.i.J' "' lLi <!) ct: "" ~ i:i.: ~ ,::; "" (.j ~ _--, Ii• iMXrl'r1'nRa ' ' -£, f.{ /!38/'"3:J3G 1, (-- /'IOIS/1131! .CW'O I 'ii :! d NOS13N M NOf d0c»:i:JN'J1S3G ----~ ' ---~J.:) S'l:I: 11 !.1.11\JS 'v C / L__ NOl fJNIHS'rfM N01N3cf dO )..1/a S 01/0cf 10f11Vl 90t£ M3//I A3111f/l :J 77 'SEJN/G70H G\flf dt/W :KJNt/J..31tNO:J Wt/3cilSNMOO ~ N/St/8 6 z <t: ...J I- ' " ~I I 0' 0- -I I --_-_-_--l:..:----=-----=- I I / EOZS-99trSZt 90086 'iM ·anA81189 a:JBld LIil\:' 3S £98G~ va -C, ~ -Ci C") ~ (!) ~ ~ ~ ~ Li: ~ Preliminary Technical Information Report Valley View Figure 3.2 -Sensitive Area Map LAND DEVELOPMENT ADVISORS, LLC. 11 December, 201 3 ~ \Jsere\,;d,,.n\Jocurn~ols\Lo,-~ )e,eloo"len·. /,d,;,c,,\Dces\Rcvurls\TR\tlCU~ES\SF~S Af.:0 A 0JGSdwc «flg -'-'" Flolle~ l.!/i</!:)lj · Cl,=, At,.< elf AM·,n (c) L~~ ~ !! ~ \ia ~ (;) ~ ~~ ~ c::; c::, _,_ (f) 0 -----C ;o ----() --rn --.,. ;o m z """ 0 ----z .. · --// Gl -----.,. .,. (f) _.-_. _. I .,. _. I // ~ DA Planning, Engineering, Project Management Land Development Advisors LLC 12865 SE 47th Place Bellevue WA 98006 425-466-5203 I // - ~ C, ~ m z ~ m "l g; g CITY OF RENTON I r I ~oc11oca1v11 --- / 0 z I )> N )> ;o 0 ::! JI '7.'i.....___ '-._(' I Cl) --i m SENSITIVE AREAS RAD HOLDINGS, LLC VALLEYVIEW 3106 TALBOT ROADS. 1\ r::-·-- I ~ z 0 (/) r °' m' I ~ ;o 0 ~ -+ ' \ I L __ _j I I __.... I \.__....----l- otS/GNGROUP I Np DAIEI RH'/SJON .ION__!!_.!'!§~0.'!,_!'5:._ ---- ,LJ,C•)/1 ";1 .'.!,'.",~,,/ii MO J,'1'1< J,',':, ,;,,fi'' DECEW3ER. lrm SENS ARCA FiGS WASHINGTON ~ ,, "" s:, ~ t:l .<: ill !"'1 Ni ;;;: 'is: i BY CK I I I I I Pre limin ary Techn ical Info rm atio n Report Figure 3.3 -NRCS Map ... :! -~" ~ •·"' ,T ~ .. ~ ~ ' V.,Sc:.· t ·J.1601Cl""9don1'~ 11·.a.,-Ja-. ~11alResou--ces Conservation Sefvioe LA ND DE V ELOPMENT A DV ISORS , LLC . 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( ; r-- 1 I --~-~ I iJ I - ' I Ii ~ '"'"",..~. 1 D A Planr1111g, Eng111eering Pr~Je':.'._~ar:~gemerst I i!nd Development Arlv,sors. l.l_C 1?865 SE 47th Place Gellevue WA 980QG 475-466-5703 CJ) m m CJ) ::c m m -i U1 "T1 0 ;a "C ;a 0 "T1 I"" m CJ) _/ ,,1 1, t:,: ' ,.): • I! 1, i I I I I' lu, 11 w "' z 0 -0 ! ! ~ r' ii l!, ,, ;-,;1cfB" ' 1 1 ~ ,,;tr,;· ~§ : ! 1 ' ' '' c5 I I 111 11 i ' I I I I I i ' I I ~t-1-n ~ fl JJ, ' " ,, I :i _,, 'r-_' ""'"-~~-- I ._:_',r----iLJ_ -,,~.,_~, I ,~,J1 1/ . 'JJ' ~ I: I ' 1//-w 1: ' 1: ~ I 11 / , , ' • I ' ' '. I 1 I' l· l :' I I " " I \. ) I ---Vl' TR/ic:rr:-- ' 11 ;; F'. .j·,, -, -~j ' 'I "-' ,, \ ~ l : I ---ft...-~-;_, _-c _;; I I :,; ~LI ~t I I '.'? ' I 1 · · 1 ,u_j~ F1t=~'"'0, ·-·~ 1:i _· -~_. 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DISTURBANCE LIMIT "', r ---_ -.,_ " . ----' -1000. 00' ----:____ l f "" 54 &' -------,--'--:_::---, \ \ I \ 131 ' __ 55 ~ --;J "'--' , 1 ', II . -~ --• ~, • I -e, "' ::::C. \ \ \ \ ---: r \ ·r:/"' ·12, 132 -1,:,_ ~~<,~--I\, , ----..,_____ l _Ll/ ~:.c-__ i \~ (])1/ Jl/r ,,. "' ~ ~ TRACT A '_NGF'E 61 ', I j !,~ --66 1 I I I I - -, l' • I -• ' ' '· • --'-64 65 I ? !1 l -. ..;,~. ai o I I I , I -" l;_ iL \, '1~ e I--I 12T 1,, :.f :: : ·4~7J O r§/ / --~ --+.._ -7,s,;" Ii~ \ , 11 :11 g i 2 '°1'w -·":~. . 12, \ '7,. TY>'F J 'NFTI AND -1_ 0. ' -29 ;g ' ! c::i " a" ~ i5 • ~ ~ " 0 " 0 " " 0 ' z 0 S2 :'l ~ ~: s ~ ~ ~; ~ • I ,: ~ I ,o "J , '° i '° t[' -,1,: .,.,.:)--121 -~ ' I -79 .,J;' ~-' NI J \~!' I I ' 111 '>0 ' 11 / 122123 ---S1 1 % I \ ~ I _ _ I ". :. Ii • I • ,;.1 I , "\~ ~-___ ------1-lj'l, ) ,_ '< a, oo a~-~ /" I ::_, - I / y ' -,_ __ ------I 999.81 I 45 //// " ' _Ji 2: «: z ;:i ('] z l' U) <{ s ~O, -5 . -,_' 6 c:i : 3 C, a" C, ~I ;:,- '/ ! -~ I / • © 1~8; ii -- ,-- ·..:., ~ ~ ~ 15 @---1.-----e--------_ _ __ N89'40'03''.'f<' -@ (@5 30 __ -\_1 -174 --l -. , ---26'-. ,1·" _· ,, :;-·,r 8 ---170~ ---168 -~------166 ---- I \,, 164 ---·-162 -' .--,-10 _~-, 1123 o--- "' I 1 '-" 14 -·"'- · 28 --· '_ · I ~ , I -16 - ' g ~ 431 i L i,,b 141 ~ ;r----+ I ,1 -t~ I \,, ,! I I \ '[ : ±J __ L_ c----_ ' j ·: " '" ' l_ ~ ~ ~ j li ~---~----- --N89"40'04"W /_ --~~----- I ,I .+ RETAINED TREE -,--c, .. -.:31 32 33. ~--:_ 35 -::::::;i 'I I -< "' L . I //) ~( Call 2 Work·ng Days Before Yow D,g 1-800-424-5555 Ut1l1ties Urdergrnund Location Center ID_MT. NQ_Q_f_WA -' Q C'.l ~ f--ct: «: c5 a: -' >-0 ct: ~ ~ «: -~ ~ C'.l - 2: u:: >== ct: f--Q ::, 0 UJ UJ g; 0 3:: "' j LU i Cf) 5: [t C'.l c--~ >-iii Cl ~ -J LU ~ 0 :r: Cl ~ c • E 1l, ~ " ~ ~ 6' ~ rn C * a, C w C go § ~ C C 0:: ~ <~ E C § C ' C ~ ..... ..... ~ ,p~···-- " ~ Q ~ i'' ::.----\'~·. ... ::-···'<>-'1-. ,:-', -~~·"" . '~ ,.~ ,,, 1' __ ' ' ' . ../1:i ~ ',,-, ; : ' ;,-~1--' • If° < _· ::· / l ·\,~~..;.··· "TAI.JP ~::JT o',>LIC UNLC~O ~IGM,r; ON J <)~ l C l z 8 z cu " 0 >-~ 0 I.IOR NIJM~ER 1--c_~, ... -~".=.,,~----i RADX-001 ::iHE~ r r-.,~r~t:1tK 6 cc 6 Preliminary Technical Information Report Valley View SECTION 4 -FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN EXISTING SITE HYDROLOGY The existing basin includes the areas outlined on Figure 3.1. The project site is in the Sea-Tac rainfall region with a scale factor of 1.0. The lot area for the existing home on the westerly portion of the property that will remain unchanged as well as the NGPE tract area are excluded from the analysis. The offsite access tracts are also included. The following table summarizes the existing areas and surface characteristics for KCRTS: Existing Basin Summary Area Area (sf/ac) Site 99,994 Offsite Access Tracts +4,839 Existing Home Lot -18,168 NGPE Tract -12,822 Existing Basin 73,843/1.70 Existing flows resulting from KCRTS are: Flow Frequency Analysis Tine Series Fi:e:dees ex.tsf Project Location:Sea-Tac ---A:-:nual Peak L_ow Races--- Flow Rate Rank Time of Peak (CFS) 0.107 2 2/09/01 18:CO 0.029 7 1/06/02 3:00 0.080 4 2/28/03 3:00 0. 003 8 3/71 /04 )0:00 0.047 6 1/05/05 8:00 0.083 3 1/18/06 21:00 0.069 5 11/24/06 4:00 0.137 1 1/09/08 9:00 Computed Peaks LAND DEVELOPMENT ADVISORS, LLC. -----Flow --Peaks (CFS) 0.137 0.107 0.083 0.080 0.069 0.047 0.029 0.003 0 .127 14 Frequency Ra:1.k 1 2 J 4 j 6 7 8 Surface Character Forested " N/A " Analysis------- Return Prob Period 100. 00 0.990 25.00 0. 960 10.00 0.900 5.00 0.800 3.0C 0. 667 2.00 C.500 1 . 30 0. 231 1 . 1 0 0. 091 00.00 0. 980 December, 2013 Preliminary Technical Information Report Valley View DEVELOPED SITE HYDROLOGY Impervious areas were determined for the onsite road and the lots. Lot impervious areas are 4,000 square feet per lot or the maximum allowed by code whichever is less. The R-8 zone allows 75% impervious. The total lot area is 53,422 sf and 75% impervious would be 40,067 sf. This area encompasses 8 lots which would be 32,000 sf at 4,000 sf per lot; however, due to the preliminary nature of this report, we will use 40,067 sf for the lot impervious area. The following table summarizes the developed areas and surface characteristics for KCRTS: Developed Land Use Summary Table Use Area (sf/ac) Surface Character Impervious Onsite Roads 3,616 Impervious Lots 40,067 " Offsite Access Tracts 4,839 .. Total Impervious 52,085/1.20 Impervious Landscaped Lawn (Total Basin -Total 0.50 Ac. Grass Impervious) Total impervious area is 1.20 Ac. Grass area is 0.50 Ac. Developed flows from KCRTS are: Flow r·requency Analysis Time Ser~es File:dees dev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Flow Ral:e Rank Time of Peak (CFS) 0.319 6 2/C9/0i 2:00 J. 2 67 8 1/05/02 16:00 0.381 3 2/27 /03 7:00 0. 297 7 8/26/04 2:00 C.356 4 i0/28/04 16:00 C.339 5 1/18/06 16:00 0. i,32 2 10/26/06 0:00 0.637 1 1/09/08 6:00 Computed Peaks PERFORMANCE STANDARDS -----Ylow r'requency Analysis------- --Peaks Rank Return Prob (C?S) Period 0.637 1 lC0.00 0.990 0.432 2 25.00 0. 960 0.381 3 10.00 0.900 0.356 4 5.00 0.800 0.339 5 3.0C 0.667 0.319 6 2.0C 0.500 0. 297 7 1.30 C. 231 0.267 8 1.10 0.091 0.568 50.00 0. 980 Basic water quality and Level 2 flow control was utilized to size the detention vault. The flow control applied to the site includes matching durations from 50% of the 2-year to the 50-year peak. Additionally, the 2-year and 10-year developed peak flows must be below the 2-year and 10-year existing peak flows. Since duration matching is part of the analysis, 36 intervals were used. The first cutoff was 0.0235 [50% of the 2 year existing flow] and the interval size was LAND DEVELOPMENT ADVISORS, LLC. 15 December, 2013 Preliminary Technical Information Report Valley View [0.127-0.0235]/35 or 0.0030. The required storage volume is 24,300 cubic feet. KCRTS output is included in the Appendix. FLOW CONTROL SYSTEM Resulting design produced by KCRTS results in a 70'x40' vault with an active storage depth of 12'. Two orifices are used with a bottom orifice diameter of 0.56" and an upper orifice 7.5' higher with a diameter of 0.90". Refer to Appendix B for the KCRTS vault output. The following graph compares the existing duration to the duration of the vault outflow. ~ 0 0 0 "' 0 in 6 R "-,e. ~--. • • • • • • • • • f";FF::c:~r'.:-:1,1-,:·;· IXLS f:X du· • ~ "' 2' 0 6 ,_ _______________ ~·~-------------------- ~ ~ ~ ~ i5 ;,; 0 N 00 0 0 0 0 0 0 10 -5 10 -4 10 ·3 Duration Comparison Anay:__si_s Base File: dees ex.tsf New File: deesrdout.tsf Cc.:.toff Units: Discharge in CFS -----fraction of Time----- Cutoff Base New %Change 0.020 0.13E-01 0.37E-Cl 176.6 ' 0.027 0.7.SE-02 0.65E-07 -12.G 0.033 O.SSE-02 0.56E-02 _,5 0.040 0.41E-02 0.40£-02 -2.C 0.047 0.31E-02 0.26E-02 -17,7 0.053 U.24E-:J2 0.20£-02 -17,6 0.060 O.lE-02 0.13£-02 -26.0 0. 067 0.:2E-02 0.SJE-03 -49.3 0. 074 C.68E-03 0.18E-03 -73.8 0.080 0.38E-03 O.OOE+OO -100.0 0.087 0.26E-03 O.OOE+OO -100. 0 0.094 0.16E-C3 O.OOEIOO -100.0 0.100 O.llE-03 O.OOE+OO -100.0 0.107 0. l6E-04 O.OOE+OO -lCO.O LAND DEVELOPMENT ADVISORS, LLC. • • • • • .... .,. .. • 10 -2 Probability Exceedence ---------Check of Probability Base 0.13E-01 0.020 0.75E-02 0. 027 0.55E-02 0.033 0.4:E-02 0. 01,0 0.31£-02 0.047 0.24£-02 0.053 0.17E-02 0.060 0.12E-02 0, 067 0.68E-03 0.074 0.38E-03 0.080 0.26E-03 C.087 O.lEE-03 C.094 0. llE-03 C. :oc o.:6E-04 0.,01 16 10 -1 To~erance------- New '~Change 0.022 10.9 0. 023 -13.5 0.034 1. 7 0.040 -0.5 0.044 -6.9 0.048 -:o.o 0.056 -7.0 0.061 -8.8 8.065 -11. 7 0. 070 -12.3 0.071 -18.0 0.074 -21.1 0.010 -25.5 0. 077 -28.6 December, 2013 Preliminary Technical Information Report Valley View Maxinun positive excu.:::-sion -~ C.C02 cfs ( :..0.9-::) Somefinetuningwillbenecessaryatthe construction plan stage. This is sufficient accuracy to demonstrate feasibility for the preliminary plat. occurr~ng at 0.020 cfs on ~he Base ~ata:dccs cx.tsf and at 0.077 cfs or1 tt1e Kew ~ata:deesrdou~.~sf Maximum ~egaLlve excursion~ 0.031 cfs (-28.6%) occu~ring at 0.10·; cts on the Base Data:dees ex.~sf and at 0.077 cfs c~ the New Data:decsrdout.tsf WATER QUALITY SYSTEM The site will utilize dead storage within the vault. Wetpool Volume The KCSWDM specifies that the following equation be used when sizing wet facilities. A summary of the water quality facility sizing calculation is provided below. The wetpond volume (Vb) is calculated from the volume of runoff (V,) from the mean annual storm and multiplying it by a volume factor (f) of 3.0. V, = (0.9A, +0.25A,9 +0.10Att + 0.011\,)* R/12 Where V, = volume of runoff from mean annual storm (cf) A,= area of impervious surface (52,085 sf) A,9 -area of till soil covered with grass (21,780 sf) Att area of till soil covered with forest (0) A0 = area of outwash soil covered with grass or forest (0) R = rainfall from mean annual storm (0.47'') [Figure 4.3 (6.4.1.A)] V, = (0.9(52,085)+0.25(21, 780))*0.47/12 = 2,049 cubic feet ("cf') Vb= V, * f = 2,049 *3 = 6,148 cf Required Water Quality Volume = 6,148 cf. The volume provided in the vault would be at least 4' of dead storage, therefore, the minimum volume available = 4'*40'*70' = 11,200 cf. During final design, a portion of the vault would not contain dead storage. Refer to Appendix B for a hand sketch of a typical vault. Overflow Analysis Overflow elements will be sized for the 100 year flow determined by KCRTS using 15 minute time steps. The results of that analysis are: Flow Frequency Analysis Time Series File:deesdevl5.tsf Project Location:Sea-Tac ---Annual Per.1.k Flow Rates--- Flow Rate Rank Time of Peak (CFS) 0.820 6 8/27 /01 18:00 0.561 8 1/06/02 1:00 LAND DEVELOPMENT ADVISORS, LLC. -----Flow ~requency Analysis------- --Peaks Ran:-< Return Prob (C:S) Period 1.87 1 100.00 0.990 L.52 2 25.0C 0.960 17 December, 2013 Preliminary Technical Information Report 1. 52 2 12/08/02 l 7: l.':::, C.576 8/25/04 23:45 C.892 3 '.1/17/84 5:0C C. 35_:_ 5 _0/22/:)S 10,00 0.88C 4 :_0;2s/:J6 22, 4j 1. 87 1 1/09/38 6,30 Computed Pea:<s Riser Pipe C.392 C.38C C.851 r,. 82(; 0. :J7 6 C.561 1. 7 5 3 4 5 6 7 8 Valley View 10.00 0.900 S. 00 J.800 3.00 :J.667 /.. 00 0.500 1. 30 0. 231 1.10 0 . .J91 50.00 J.980 The control structure has two orifices on an 12" riser. The riser is designed to have enough head above it to safely pass the 100-year peak developed flow. Refer to the Riser Nomograph in Appendix B. Q = 2.0 cfs, Riser diameter= 12" --. H = 0.35'. LAND DEVELOPMENT ADVISORS, LLC. 18 December, 2013 Preliminary Technical Information Report Valley View Figure 4.1 -Basin Map LAND DEVELOPMENT ADVISORS, LLC. 19 December, 2013 .. . n '''''l , .. J(ll "'1-..1.-1 -., l .c?· ~ ~-if><!:I!: "' I 0 ~1.,/ -.)\ I I• King County 6 N t 1r,· '! \ .i j Basin Locations Surface Wa ter Utility Comprehe nsive Plan Printed 10/16/20 09 ::. ,.f, f.711 ' , 0 1{\;. ' .:-'l tt:-.1 "i. .... ,~ .:i-:'!-, -..: .f I ; ' l \f ,'J ,·1 J<l) ... r .. 0 .5 Miles I J 1 ; ; ··'< ') ~,....,,1 \"·-'' ,, ·-,1~ 6 , .. ·"·~·~ .ft'l 'v ,:,(· ( //11 1 1/11(('/ l }llf(lll,'t 'tl -.... .~ ; ~ " ~· $ Bellevue '~ ' . -:'· ~ \-.. I i,..n.t1 i " ., '-'::-_,. '- ! L """"'' ,I I ~~ r'7'·, r..;.., . : ..... 4 "'··-~"7 ; -·--· .. -··-··-··---' .. I l"!'t "' ~ 7, 1· .,.. .. _._;_,,"'\ ,•"·---·, ::: . • -::: I i . -~ . '---••-••-••.; ...._. I • ' C r'\',• ,··-··-· ... ·-··--··-··--..,,• ·-:, '~ I ,. , I ', ' \ \ \ / l:-··: Renton C ity Limits ---~ l:-": Potentia l Annexation Area ___ .. Basins Black Rive r __ Duamish LJ Lake Wash i ngton East [__J Lake Wash ington West I Lower Cedar River L J May Creek ~ ' Soos Creek i Preliminary Technical Information Report Valley View Figure 4.2 -Rainfall Regions and Regional Scale Factors I r------,.-JC-_-UU:--Ul.A--MN---ALL--ll&WONI--. --~-NU-~-Ol'U--._-5('-AJZ--,-.,-CI"O--IS------j ST 1.1 ·• ST1.0 Rainfall Regions and Regional Scale Factors a~ ~po.allld.-,:w -c..> ,... .... ---- LAND DEVELOPMENT ADVISORS, LLC. 20 v . ·x·. -'""'-... . ' It'. .... ~ I • -' '' ~?:· . ... . .... ' ~ :r~~~-·. .-. ~~~~r . . -~ . . . -... . ,. - December, 2013 Preliminary Technical Information Report Valley View Figure 4.3 -Precipitation for Mean Annual Storm 4, I ~S-II.Uk~ ANIJ UJt<a . IICTJIO{U ,>r J.!AALTS:J o.:-.... (1.045") •1 NO.,._d~ ..... ----NDff: --.... ... ....... ........ o.. .................... Wiil ..... larcllal ... ..... "'•-------··-----.... ...................... _ ........... .... _. ... ,... ff lGi '-l. o., U 1 0 " ' I..' I J ' .• /'-~. C lliil• -, . •._ --. ·-/ -· ............ •.D. ••l · 1 \.,,-,.__,:/ " ••• ' ~.~,• l'J.~"lt'I IC U?'I ........ "' -.. ,. _ ct __ fa, ...... A(-p-till .... l t)POII --~ md --...ii._ and alluW>II Md_....., klll, 1U1 ._.,. a •-"Y ~IP __, -"' 1tt -in "' • ,hallow dlopCII (lel1 doln S INC) by gll<ill 1111 I: .S ibl c;,_.,...,. S....00 (SCS\lmlrologi< Pil r,nu, .. lhM -<tu.....i"' rnl oollo iacilaio • r .... · 11. -(..ad .. , o ..,.,, S.,· C1la,itt J lot ,I "fiaaon di lpe<lfl( SCS sail typn. LAND DEVELOPMENT ADVISORS, LLC. 21 December, 2013 Preliminary Technical Information Report Valley View SECTION 5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN For development projects, new conveyance systems shall be designed with sufficient capacity to convey and contain the 25-year peak flow. Pipe systems may overtop for the 100-year peak provided there is no creation or aggravation of a "severe flooding problem" or "severe erosion problem". There are no such areas within or Y. mile downstream of the property. Calculations for the onsite system will be provided with the construction plans. A 12" pipe at a slope of 0.5% will convey 2.7 cfs (ADS N-12, n=0.012). Based on the 25 year flow calculated above of 1.52 cfs, 12" pipes can be used throughout. LAND DEVELOPMENT ADVISORS, LLC. 22 December, 2013 Preliminary Technical Information Report Figure 5.1 -Catchment Map Will be provide after first review. LAND DEVELOPMENT ADVISORS, LLC. Valley View 23 December, 2013 Preliminary Technical Information Report SECTION 6 SPECIAL REPORTS AND STUDIES Please refer to the wetland and geotechnical reports in Appendix C. SECTION 7 OTHER PERMITS Valley View In addition to permits from Renton, a Storm Water Discharge Permit will be required from the State of Washington. LAND DEVELOPMENT ADVISORS, LLC. 24 December, 2013 Preliminary Technical Information Report Valley View SECTION 8 ESC ANALYSIS AND DESIGN Development of the project site will require earth disturbance. As a result, special attention needs to be given to the construction stages of development. This section of the report, along with the Temporary Erosion and Sedimentation Control (TESC) plans, serve as a guide to minimize the effects of erosion onsite and off-site. The temporary erosion and sediment control plan will be provided with the final construction plans and will be in conformance with the King County Surface Water Design Manual (2009). The following elements discuss typical measures that would be utilized on the project site to that it will conform to City erosion and sedimentation control standards. Element #1: Mark Clearing Limits Clearing Limits will be flagged by the surveyor and/or fenced by the contractor prior to commencement of construction activity. Element #2: Establish Construction Access A rock-construction entrance (or equivalent) shall be installed in conformance with City erosion control standards. The City may, at its discretion, require a wheel-wash facility in addition to the rock construction entrance if it determines the entrance is not adequately preventing the tracking of sediment from the site. Element #3: Detain Flows All surface runoff generated during construction will be controlled by perimeter filter fabric fence prior to release. In addition, a sediment trap will be provided. The sediment trap size required is shown on the TESC plan. Element #4: Install Sediment Controls Sediment controls for the project site shall consist of catch basin protection and filter fabric fencing installed around the down slope perimeter. Element #5: Stabilize Soils The temporary erosion and sediment control plan calls for the stabilization of exposed soils through jute netting, mulching and/or hydroseeding when the soils are not to be worked for a significant period of time. The plan also calls for the establishment of permanent vegetation through hydroseeding once the site has reached final grade. Element #6: Protect Slopes The temporary erosion and sediment control plan calls for the installation of filter fabric fencing along the downstream limits of construction. During construction, the majority of earthwork will occur on gently sloping terrain. Side slopes of soil stockpiles shall be temporarily covered with plastic until the stockpile materials are used or exported from the site. Element #7: Protect Drain Inlets The Temporary Erosion and Sediment Control Plan calls for a filter fabric sock to be installed at all newly constructed catch basin inlets and all existing inlets which lie immediately downstream of areas under construction. Element #8: Stabilize Channels and Outlets The ditch along Talbot Road at the vault outfall will be stabilized with rip rap. LAND DEVELOPMENT ADVISORS, LLC. 25 December, 2013 Preliminary Technical Information Report Valley View Element #9: Control Pollutants All waste materials shall be disposed of in an approved location, in accordance with City Standards. In order to reasonably prevent a contamination event (such as a fuel spill), vehicle maintenance shall occur off-site to the greatest extent practicable. Any contamination event that occurs should be immediately contained and remedied to the satisfaction of the County. Element #10: Control De-Watering No significant amount of dewatering is expected to occur during this project. Element #11: Maintain BMPs All BMPs should be monitored and maintained regularly to insure adequate operation. A TESC supervisor shall be identified at the beginning of the project, to provide monitoring and direct appropriate maintenance activities. As site conditions change, all BMPs shall be updated as necessary to maintain compliance with City standards. Element #12: Manage the Project The project will begin with a pre-construction conference, in which an onsite TESC supervisor shall be identified. The onsite supervisor shall monitor all TESC facilities regularly and maintain a log of inspections and improvements to demonstrate compliance with City standards. It is important to ensure that the entire site is in conformance with County erosion control standards at all times. The TESC supervisor shall notify Land Development Advisors, LLC of any problems with the proposed erosion control elements, or if any revisions to the plans need to be made. Additional erosion control materials, such as filter fabric fencing, plastic cover and straw bales, shall be kept onsite at all times in the event that an erosion control feature needs to be replaced or installed. SECTION 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT Bond Quantity estimates will be provided for the final construction plans. Declarations of Covenant that may be necessary will be executed prior to plan approval. SECTION 10 MAINTENANCE AND OPERATIONS MANUAL The City will assume maintenance responsibilities for the facility. SECTION 11 REFERENCES King County 2009 Surface Water Design Manual. LAND DEVELOPMENT ADVISORS, LLC. 26 December, 2013 Preliminary Technical Information Report Valley View APPENDIX A-PHOTOGRAPHS LAND DEVELOPMENT ADVISORS, LLC. 27 December, 2013 Prel im inary Technical Information Report Valley View Photographs Photo 1: This view looking north along the east side of Talbot Road from the northwest corner of Winspur. Maintenance of the culvert inlets and ditch line is necessary. The site is approximately 250' north of this location . LAND DEVELOPMENT ADVISORS, LLC . 28 December, 2013 Preliminary Technical In fo rm ation Report Valley View Photo 2: This view lookin g west from the locat io n in photo 1 shows th e route of the 21" pipe as it heads west throu gh private property on the right s id e of th e f e nce . LAND DEVELOPMENT ADVISORS , LLC . 29 December, 2013 Preliminary Technical Information Report Valley View APPENDIX B-SUPPORTING DOCUMENTATION LAND DEVELOPMENT ADVISORS, LLC. 30 December, 2013 Preliminary Technical Information Report Valley View Section 303d Listing LAND DEVELOPMENT ADVISORS, LLC. 31 December, 2013 ..... Washington State Department of Ecology ..... 2008 Water Quality Assessments __ sting Detail Category WRIA Water Body Name Parameter Medium Map Link 4672 4C 8 WASHINGTON LAKE Invasive Exotic Species Habitat 467? 4676 4C 8 WASHINGTON LAKE Invasive Exotic Species Habitat 4676 8078 2 8 WASHINGTON LAKE Lead Water 8078 WJJ3Q 2 8 WASHINGTON LAKE Ammonia-N Water U36.Q 11963 2 8 WASHINGTON LAKE Ammonia-N Water 11963 11964 2 8 WASHINGTON LAKE Ammonia-N Water 11964 11970 2 8 WASHINGTON LAKE Ammonia-N Water 11filQ l.UE2 8 WASHINGTON LAKE Ammonia-N Water 1.1972 11973 8 WASHINGTON LAKE Ammonia-N Water 11973 12182 5 8 WASHINGTON LAKE Fecal Coliform Water 12182 12184 5 8 WASHINGTON LAKE Fecal Coliform Water 12184 12186 2 8 WASHINGTON LAKE Fecal Coliform Water = 12187 5 8 WASHINGTON LAKE Fecal Coliform Water .12J 87 12188 5 8 WASHINGTON LAKE Fecal Coliform Water 12188 12189 5 8 WASHINGTON LAKE Fecal Coliform Water 12189 12191 5 8 WASHINGTON LAKE Fecal Coliform Water 12191 12193 5 8 WASHINGTON LAKE Fecal Coliform Water 12193 12194 2 8 WASHINGTON LAKE Fecal Coliform Water 12194 1219~ 5 8 WASHINGTON LAKE Fecal Coliform Water 12195. 12196 2 8 WASHINGTON LAKE Fecal Coliform Water 12196 12198 5 8 WASHINGTON LAKE Fecal Coliform Water 12198 12199 5 8 WASHINGTON LAKE Fecal Coliform Water 12199 12202 5 8 WASHINGTON LAKE Fecal Coliform Water 12202 12204 5 8 WASHINGTON LAKE Fecal Coliform Water 12204 12205 5 8 WASHINGTON LAKE Fecal Coliform Water 12205 12206 5 8 WASHINGTON LAKE Fecal Coliform Water L2206 12207 2 8 WASHINGTON LAKE Fecal Coliform Water 1220? 12208 5 8 WASHINGTON LAKE Fecal Coliform Water 12208 12264 2 8 WASHINGTON LAKE Mercury Water 122"'1 12272 2 8 WASHINGTON LAKE Mercury Water 12272 12311 2 8 WASHINGTON LAKE PCB Water 12311 12312 2 8 WASHINGTON LAKE PCB Water 12312 12313 2 8 WASHINGTON LAKE PCB Water 12313 12314 2 8 WASHINGTON LAKE PCB Water = 12315 2 8 WASHINGTON LAKE PCB Water 12315 12316 2 8 WASHINGTON LAKE PCB Water 12316 12317 2 8 WASHINGTON LAKE PCB Water 12317 n,18/2012 3:17:35 PM 1 of 3 ._ .. Washington State Department of Ecology • ,.. 2008 Water Quality Assessments _.sting Detail Category WRIA Water Body Name Parameter Medium Map Link 12318 2 8 WASHINGTON LAKE PCB Water Jn1s 43481 8 WASHINGTON LAKE Toxaphene Tissue 43481 43482 5 8 WASHINGTON LAKE PCB Tissue 43482 43483 8 WASHINGTON LAKE Mercury Tissue 43483 43484 8 WASHINGTON LAKE Hexachlorobenzene Tissue 43484 43485 8 WASHINGTON LAKE Heptachlor Epoxide Tissue 43485 43486 8 WASHINGTON LAKE Heptachlor Tissue 43486 43487 8 WASHINGTON LAKE Gamma-bhc (Undane) Tissue 43487 43488 8 WASHINGTON LAKE Endrin Tissue 43488 43489 8 WASHINGTON LAKE Endosulfan II Tissue 43489 43490 8 WASHINGTON LAKE Endosulfan I Tissue 43490 4349J. 8 WASHINGTON LAKE Chlordane Tissue 43491 43492 8 WASHINGTON LAKE Beta-BHC Tissue 43492 43493 8 WASHINGTON LAKE Alpha-BHC Tissue 43493 43494 8 WASHINGTON LAKE 4.4'-DDT Tissue 43494 43495 8 WASHINGTON LAKE 4.4'-DDE Tissue 43495 43496 8 WASHINGTON LAKE 4,4'-DDD Tissue ±3±91) 51591 5 8 WASHINGTON LAKE 2,3.7,8-TCDD Tissue 51591 51592 5 8 WASHINGTON LAKE 2,3,7,8-TCDD Tissue 51592 51593 5 8 WASHINGTON LAKE 2,3,7,8-TCDD Tissue 51593 51644 2 8 WASHINGTON LAKE 2,3,7,8-TCDD TEO Tissue 51644 51645 2 8 WASHINGTON LAKE 2,3.7,8-TCDD TEO Tissue 51645 51646 2 8 WASHINGTON LAKE 2,3.7,8-TCDD TEO Tissue 51646 51706 5 8 WASHINGTON LAKE 4,4'-DDD Tissue 51706 5_1767 5 8 WASHINGTON LAKE 4,4'-DDE Tissue 51767 51827 8 WASHINGTON LAKE 4,4'-DDT Tissue 51827 51949 8 WASHINGTON LAKE Alpha-BHC Tissue 51949 52010 8 WASHINGTON LAKE Beta-BHC Tissue .52010 52403 B WASHINGTON LAKE Gamma-bhc (Lindane) Tissue 52403 52464 8 WASHINGTON LAKE Heptachlor Tissue 52464 52585 8 WASHINGTON LAKE Hexachlorobenzene Tissue 52585 52642 8 WASHINGTON LAKE Mercury Tissue 52642 52703 5 8 WASHINGTON LAKE PCB Tissue 52703 52704 5 8 WASHINGTON LAKE PCB Tissue 52704 52705 5 B WASHINGTON LAKE PCB Tissue 52705 52766 5 8 WASHINGTON LAKE Total Chlordane Tissue 52766 52853 5 B WASHINGTON LAKE Total Phosphorus Water 52853 n,18/2012 3:17:35 PM 2 of 3 ..... C sting Detail Category WRIA 52854 8 2>285S 8 52856 5 8 52857 8 52858 8 52859 8 52861 8 52862 8 = 8 52864 8 52865 8 . Jmber of Listings 85 ~/18/2012 3:17:35 PM Washington State Department of Ecology 2008 Water Quality Assessments Water Body Name Parameter WASHINGTON LAKE Total Phosphorus WASHINGTON LAKE Total Phosphorus WASHINGTON LAKE Total Phosphorus WASHINGTON LAKE Total Phosphorus WASHINGTON LAKE Total Phosphorus WASHINGTON LAKE Total Phosphorus WASHINGTON LAKE Total Phosphorus WASHINGTON LAKE Total Phosphorus WASHINGTON LAKE Total Phosphorus WASHINGTON LAKE Total Phosphorus WASHINGTON LAKE Total Phosphorus 3 of 3 Medium Map Link Water 52.8~4 Water 52855 Water 52856 Water 52857 Water 52858 Water 52859 Water 52861 Water 52862 Water 52863 Water 52864 Water _;;_28Vi Preliminary Technical Information Report Valley View Vault Sketch LAND DEVELOPMENT ADVISORS, LLC. 32 December, 2013 ID A Land Development Advisors, LLC \.) ,;,.A I ,:;:;:--.J j 1 I ....-----\ Project _;;:.:r:.:···..s •v::.:·~=jc::_:1 _ _;;:_· -'-'. ~=-·~'"c.:"cc·J _____________ Date ____ ._::i_-~~------ IF-;::. r; I j ~-__ J, ) V y:VI.,,{__,( d ' 1---+-s},4-- . j ~-1 \- ' A ' lCJ X '-10 12865 SE 47th Place, Bellevue. WA 98006 ' ) I ' By ..._:,../_ ---.., Page --'---of -'--\ __ ---~/ . ·v . ~-----. Soo-:i ¢-=-\ 4 .:: -'.) --,11 I t I ' L 2-o (425) 466-5203 Preliminary Technical Information Report KCRTS Output Re~ention/Detention Facility Type of Facility: Facility Length: Facility Width: Facility Area: Effective Storage Depth: Stage O Elevation: Storage Volume: Riser Head: Riser Diameter: Nurr,ber of orifices: Detention Vault 45.00 ft 45.00 ft 2025. sq. 12.00 ft 0.00 ft 24300. cu. 12.00 ft ft ft 12.00 inches 2 Full Head Valley View Pipe Orifice# Height (ft) 0.00 7.50 Diameter Discharge Diameter 1 2 Top Notch Weir: Outflow Rating Curve: (in) 0.56 0.90 None None (CFS) (in) 0.029 0.047 4.0 Stage Elevation Storage Discharge (ft) (ft) (cu. ft) (ac-ft) (cfs) 0.00 0.00 0. 0.000 0.000 0.01 0.01 20. 0.000 0.001 0.02 0.02 41. 0.001 0.001 0.03 0.03 61. 0.001 0.001 0.04 0.04 81. 0.002 0.002 0.05 0.05 101. 0.002 0.002 0.25 0.25 506. 0.012 0.004 0.45 0.45 911. 0.021 0.006 0.66 0.66 1337. 0.031 0.007 0.86 0.86 1742. 0.040 0.008 1. 06 1. 06 2147. 0.049 0.009 1.27 1. 27 2572. 0.059 0.010 1. 4 7 1. 4 7 2 977. 0.068 0.010 1. 67 1. 67 3382. 0.078 0. 011 1. 88 1. 88 3807. 0.087 0.012 2.08 2.08 4212. 0.097 0.012 2.28 2.28 4617. 0. 106 0.013 2.49 2. 4 9 5042. 0. 116 0.013 2.69 2.69 5447. 0.125 0.014 2.89 2.89 5852. 0.134 0.014 3.10 3.10 6278. 0.144 0.015 3.30 3.30 6683. 0.153 0.015 3.50 3.50 7088. 0.163 0.016 3.71 3. 71 7513. 0 .172 0.016 3.91 3.91 7918. 0.182 0.017 4.11 4 .11 8323. 0.191 0.017 4.32 4.32 8748. 0.201 0.018 4.52 4.52 9153. 0.210 0.01.8 4. 72 4.72 9558. 0. 219 0.018 LAND DEVELOPMENT ADVISORS, LLC. 33 Percolation (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 0.00 0.00 0.00 0.00 0.00 0.00 0.00 December, 2013 Preliminary Technical Information Report Valley View 4.93 4.93 9983. 0.229 0.019 0.00 5.13 5.:3 10388. 0.238 0. 019 0.00 5.33 5.33 10793. 0.248 0. 020 C.00 5.51 5.54 11219. 0.258 0.020 0.00 5.74 5.74 11624. 0. 267 0.020 0.00 5.94 5.94 12029. 0.276 0.02: 0.00 6.15 6.15 12454. 0.286 0.021 0.00 6.35 6.35 12 85 9. 0.295 0. 021 0.00 6.56 6.56 13284. 0.305 0.022 0.00 6.76 6. 7 6 13689. 0.314 0.022 0.00 6. 96 6.96 14094. 0.324 0.022 0.00 7 .17 7.17 14519. 0.333 0. 023 0.00 7.37 7.37 14924. 0.343 0. 023 0.00 7.50 7.50 15188. 0.349 0. 023 0.00 7.51 7.51 15208. 0.349 0.023 0.00 7.52 7.52 15228. 0.350 0.024 0.00 7.53 7.53 15248. 0.350 0.025 0.00 7.54 7.54 15269. 0.351 0.026 0.00 7.55 7.55 15289. 0.351 0.028 0.00 7.56 7.56 15309. 0.351 0. 02 9 0.00 7.57 7.57 1532 9. 0.352 0.029 0.00 7.58 7.58 15350. 0.352 0.029 0.00 7.78 7.78 15755. 0.362 0.035 0.00 7.98 7.98 16160. 0. 371 0.039 0.00 8.19 8.19 16585. 0.381 0.043 0.00 8.39 8.39 16990. 0.390 0.045 0.00 8.59 8.59 17395. 0.399 0.048 0.00 8.80 8.80 17 820. 0.409 0.050 0.00 9.00 9.00 18225. 0.418 0.052 0.00 9.20 9.20 18630. 0.428 0.054 0.00 9.41 9.41 19055. 0.437 0.056 0.00 9. 61 9.61 19460. 0.447 0.058 0.00 9.81 9.81 19865. 0.456 0.060 0.00 10.02 10.02 20291. 0.466 0.062 0.00 10.22 10.22 20696. 0.475 0.063 0.00 10.42 10.42 21101. 0.484 0.065 0.00 10.63 10.63 21526. 0. 4 94 0.067 0.00 10.83 10.83 21931. 0.503 0.068 0.00 11.03 11. 03 22336. 0. 513 0.070 0.00 11. 24 11. 24 22761. 0.523 0. 071 0.00 11. 44 11. 44 23166. 0.532 0.072 0.00 11. 64 11. 64 23571. 0.541 0.074 0.00 11. 85 11. 85 23996. 0.551 0.075 0.00 12.00 12.00 24300. 0.558 0.076 0.00 12.10 12.10 24503. 0.563 0.385 0.00 12.20 12.20 24705. 0.567 0.948 0.00 12.30 12.30 24908. 0. 572 1.680 0.00 12.40 12.40 25110. 0.576 2.470 0.00 12.50 12.50 25313. 0.581 2.750 0.00 12.60 12.60 25515. 0.586 3.010 0.00 12.70 12.70 25718. 0.590 3.240 0.00 12.80 12.80 25920. 0.595 3.460 0.00 12.90 12.90 26123. 0.600 3.670 0.00 13.00 13.00 26325. 0.604 3.860 0.00 LAND DEVELOPMENT ADVISORS, LLC. 34 December, 2013 Preliminary Technical Information Report Valley View 13. :o 13.10 26528. 0.609 4.050 0.00 l3. 20 13.20 2673C. 0.614 4.230 o.oc 13. 30 13.30 26933. 0.618 4.400 O.OC 13. 40 13.40 27135. 0. 623 4.560 o.oc 13. 50 13.50 27338. 0. 628 4.720 0.00 13.60 13.60 27540. 0.632 4.870 0.00 13. 70 13.70 27743. 0.637 5.020 o.oc 13. 80 13.80 27945. 0.642 5.160 0.00 13. 90 13.90 28148. 0.646 5.300 0.00 Hyd Inflow Outflow Peak Storage Target Cale Stage Elev (Cu-Ft) (Ac-Ft) 1 0.67 0. ls 0.25 12.06 12.06 24417. 0.561 2 0.34 0 .11 0.07 11. 49 11. 4 9 23263. 0.534 3 0.34 0.08 0.06 9.99 9.99 20238. 0.465 4 0.40 ******* 0.06 10.40 10.40 21060. 0.483 5 0.36 ******* 0.04 8.02 8.02 16238. 0.373 6 0.21 0.04 0.02 7.07 7.07 14310. 0.329 7 0.28 ******* 0.02 6.77 6. 77 13716. 0.315 8 0.31 ******* 0.02 4.66 4.66 9437. 0. 217 ---------------------------------- Route Time Series through Facility Inflow Time Series File:dees dev.tsf Outflow Time Series File:DEESRDOUT Inflow/Outflow Analysis Peak Inflow Discharge: 0.673 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.254 CFS at 10:00 on Jan 9 in Year 8 Peak Reservoir Stage: 12.06 Ft Peak Reservoir Elev: 12.06 Ft Peak Reservoir Storage: 24417. Cu-Ft 0.561 Ac-Ft Flow Duration from Time Series File:deesrdout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS % % % 0.001 27761 45.272 45.272 54.728 0.547E+OO 0.003 5500 8. 969 54.242 45.758 0.458E+OO 0.005 4605 7.510 61. 7 51 38.249 0.382E+OO 0.007 4634 7.557 69.309 30.691 0.307E+OO 0.010 3883 6.332 75.641 24.359 0.244E+OO 0.012 4359 7.109 82.750 17.250 0.173E+OO 0.014 3651 5.954 88.704 11.296 0.113E+OO 0.016 2211 3.606 92.309 7.691 0.769E-01 0.018 1197 1.952 94. 2 61 5. 739 0.574E-01 0.020 1830 2.984 97.246 2.754 0.275E-01 0.022 1037 1.691 98.937 1. 063 0.106E-01 0.024 250 0.408 99.344 0.656 0.656E-02 0. 02 6 10 0.016 99.361 0.639 0.639E-02 0.028 3 0.005 99.366 0.634 0.634E-02 0.031 28 0.046 99. 411 0.589 0.589E-02 0.033 26 0.042 99.454 0.546 0.546E-02 0.035 23 0.038 99.491 0.509 0.509E-02 LAND DEVELOPMENT ADVISORS. LLC. 35 December, 2013 Preliminary Technical Information Report 0.037 31 O.C5~ 99.~42 0.458 C.458S-02 0.039 30 O.C49 99.591 0.409 C. 409"-02 0.041 37 0.060 99.651 0.349 0.349':-02 0.043 29 O.C47 99.698 0.302 C.302E-02 0.045 23 0.038 99.736 0.264 0.264E-07, 0.047 19 0.03l 99. 767 0.233 C.233E-02 0.049 9 0.015 99.781 0.219 0.219E-02 0.052 10 0.016 99.798 0.202 0.202E-02 0.054 13 0.021 99.819 0.181 0.181E-02 0.056 14 0.023 99.842 0.158 0.158E-02 0.058 14 0.023 99.865 0 .135 0. 135E-02 0.060 9 0.015 99.879 0 .121 0 .12 lE-02 0. 062 15 0.024 99.904 0. 096 0. 962E-03 0.064 15 0.024 99.928 0. 072 0. 718E-03 0.066 7 0. 011 99.940 0.060 0.603E-03 0.068 7 0. 011 99.951 0.049 0.489E-03 0.070 8 0. 013 99. 964 0.036 0.359E-03 0.073 11 0.018 99.982 0.018 0.179E-03 0.075 5 0.008 99.990 0.010 0.978E-04 Duration Comparison Anaylsis Base File: dees ex.tsf New File: deesrdout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time--------------Check of Cutoff Base New %Change Probability Base 0.020 0 .13E-01 0.35E-01 166.7 I 0.13E-01 0. 020 0.027 0.75E-02 0.64E-02 -14.8 I 0.75E-02 0. 027 0.033 0.55E-02 0.53E-02 -3.0 I 0.55E-02 0.033 0.040 0.41E-02 0.38E-02 -7.9 I 0.41E-02 0.040 0.047 0.31E-02 0.24E-02 -21.9 I 0.31E-02 0.047 0.053 0.24E-02 0.18E-02 -24.3 I 0.24E-02 0.053 0.060 0.17E-02 0.12E-02 -30.8 I 0.17E-02 0.060 0. 067 0.12E-02 0.59E-03 -4 9. 3 I 0.12E-02 0.067 0.074 0.68E-03 0.15E-03 -78.6 I 0.68E-03 0.074 0.080 0.38E-03 O.OOE+OO -100.0 I 0.38E-03 0.080 0.087 0.26E-03 O.OOE+OO -100.0 I 0.26E-03 0.087 0.094 0.16E-03 O.OOE+OO -100.0 I 0.16E-03 0.094 0.100 0. llE-03 O.OOE+OO -100.0 I 0. llE-03 0.100 0.107 0 .16E-04 0.00E+OO -100.0 I 0.16E-04 0.107 Maximum positive excursion= 0.002 cfs ( 10.1%) cccurring at 0.020 cfs on the Base Data:dees ex.tsf and at 0.022 cfs on the New Data:deesrdout.tsf Maximum negative excursion= 0.031 cfs (-29.4%) occurring at 0.107 cfs on the Base Data:dees ex.tsf and at 0.076 cfs on the New Data:deesrdout.tsf LAND DEVELOPMENT ADVISORS, LLC. 36 Valley View Tolerance------- New %Change 0.022 10.1 0.023 -13.6 0.032 -2.5 0.039 -3.3 0.043 -8.1 0.047 -12.1 0.054 -9.4 0.060 -9.7 0.065 -12.0 0.070 -12.5 0. 071 -18.4 0. 073 -22.0 0.075 -25.7 0.076 -29.4 December, 2013 Preliminary Technical Information Report LAND USE SUMMARY FOR KCRTS 15MIN SERIES t) Land Use Summary Area Till Forest 0.00 acres Till Pasture 0.00 acres Till Grass 0.50 acres Outwash Forest 0.00 acres Outwash Pasture o.oo acres Outwash Grass 0.00 acres Wetland 0.00 acres Impervious 1.20 acres Total 1.70 acres Scale Factor: 1.00 15-Min Reduced Edit Flow Paths Time Series: Compute Time Series Modify User Input L: 135.00 S: 0.10 L: 75.00 S: 0.02 ··-····-·-·-····-·---=1~>~> I I File for computed Time Series [.TSF] LAND DEVELOPMENT ADVISORS. LLC. 37 Valley View December, 2013 Preliminary Technical Information Report Valley View Riser Nomograph LAND DEVELOPMENT ADVISORS, LLC. 38 December, 2013 SFCTION o.J IJEI c'<TION FACILITIES 911198 Riser Overflow The nomograph in Figure 5.3.4.H can be used to determine the head (in [eel) above a riser of given diameter and for a given flow (usually the 100-year peak flow for developed conditions). FIGURE 5.3.4.H RISER INFLOW CURVES 100 72 54 48 10 10 ' 1 ___ _J 0.1 1 10 HEAD IN FEET (measured from crest of riser) Oweir=9.739 DH 312 Oorifice=3. 782 D 2 H 112 Q in cfs, D and H in feet Slope change occurs at weir-orifice transition 1998 Surface \Vater Design Manual 5-50 Preliminary Technical Information Report Valley View APPENDIX C -TECHNICAL REPORTS LAND DEVELOPMENT ADVISORS, LLC. 39 December, 2013 GEOTECH CONSULTANTS. INC. RAD Holdings, LLC 1040 West Lake Sammamish Parkway Southeast Bellevue, Washington 98008 13256 Northe<>st 20th Street, Suite 16 Bellevue, Washingtor:: 98005 (425) 747-5618 FAX (425) 747-8561 May 27, 2014 JN 14177 Attention: Rory Dees via email: rorydees@hotmai/.com Subject: Transmittal Letter -Geotechnical Engineering Study Proposed Residential Development 3112 Talbot Road South Renton, Washington Dear Mr. Dees: We are pleased to present this geotechnical engineering report for the residential development to be constructed in Renton. The scope of our services consisted of exploring site surface and subsurface conditions, and then developing this report to provide recommendations for general earthwork and design criteria for foundations, retaining walls, and pavements. This work was authorized by your acceptance of our proposal, P-8823, dated September 6, 2013. The attached report contains a discussion of the study and our recommendations. Please contact us if there are any questions regarding this report, or for further assistance during the design and construction phases of this project. TRC/MRM: at Respectfully submitted, GEOTECH CONSULTANTS, INC. ~C~n,P.E. Senior Engineer GEOTECH CONSULTANTS, INC. GEOTECHNICAL ENGINEERING STUDY Proposed Residential Development 3112 Talbot Road South Renton, Washington This report presents the findings and recommendations of our geotechnical engineering study for the site of the proposed residential development to be located in Renton. We were provided with a topographic survey of the site prepared by Axis Survey & Mapping dated August 28, 2013. We have also been provided with project plans by Land Development Advisors dated May 7, 2014. Based on these plans, we understand that the eastern of the two site residences will be removed and the western residence will remain. The development will consist of 8 residential lots and a stormwater detention pond. The lots will be accessed from the south with two driveways from South 32°ct Place. Retaining walls up to 4 feet high will be constructed on the eastern side of the two proposed access driveways. Grading for the proposed lots will include cuts and fills of up to 4 feet. A stormwater detention pond will be located at the west side of the development, and a cut of up to 10 feet will be made for the pond. The pond slopes will have an inclination of 2:1 (H:V). If the scope of the project changes from what we have described above, we should be provided with revised plans in order to determine if modifications to the recommendations and conclusions of this report are warranted. SITE CONDITIONS SURFACE The Vicinity Map, Plate 1, illustrates the general location of the rectangular-shaped parcel. The site is surrounded by residences and is accessed from the west by a driveway from Talbot Road South. The site has dimensions of 100 feet in the north-south direction and 1,000 feet in the east-west direction. The property is developed with two residences; both of which are accessed from Talbot Road South by a driveway along the south edge of the site. The western residence has two stories and a basement, and the eastern residence has one story and a basement that daylights toward the west. The ground surface within the site slopes gently to moderately down toward the west, with a change in elevation of about 70 feet across a distance of 1,000 feet. There are no steep slopes on, or near, the site. Approximately the eastern 300 feet of the site is thickly vegetated with young to mature evergreen and deciduous trees and brush. Most of the remainder of the site is covered with grass lawn, with scattered mature trees and landscaping bushes. Blackberry vines grow in the western portion of the planned development area. SUBSURFACE The subsurface conditions were explored by excavating four test pits at the approximate locations shown on the Site Exploration Plan, Plate 2. Our exploration program was based on the proposed GEOTECH CONSULTANTS. INC. RAD Holdings, LLC lvlay 27, 2014 JN 14177 Page 2 construction, anticipated subsurface conditions and those encountered during exploration, and the scope of work outlined in our proposal. The test pits were excavated on May 21, 2014 with a small excavator. A geotechnical engineer from our staff observed the excavation process, logged the test pits, and obtained representative samples of the soil encountered. "Grab" samples of selected subsurface soil were collected from the backhoe bucket. The Test Pit Logs are attached to this report as Plates 3 and 4. Soil Conditions The test pits found topsoil that had a thickness of about one foot. Below the topsoil, Test Pit 2 encountered loose to medium-dense silt with sand. Below this silt in Test Pit 2, and beneath the topsoil in the other explorations, we encountered loose to medium-dense silty sand with gravel. This material included pieces of dense silt in Test Pits 1 and 2. The silty sand with gravel became medium-dense at a depth of about 2 to 3 feet, and dense at a depth of about 4 to 7 feet. The dense silty sand with gravel extended to the maximum depth of the test pits, 6 to 8.8 feet below the surface. No obstructions were revealed by our explorations. However, debris, buried utilities, and old foundation and slab elements are commonly encountered on sites that have had previous development. Groundwater Conditions Perched groundwater seepage was observed at a depth of 3 feet in Test Pit 4. The test pits were left open for only a short time period, but were conducted following a very wet fall and winter. The seepage levels on the logs represent the location of transient water seepage and may not indicate the static groundwater level. It should be noted that groundwater levels vary seasonally with rainfall and other factors. We anticipate that groundwater could be found in more permeable soil layers and between the near-surface weathered soil and the underlying denser soil. The stratification lines on the logs represent the approximate boundaries between soil types at the exploration locations. The actual transition between soil types may be gradual, and subsurface conditions can vary between exploration locations. The logs provide specific subsurface information only at the locations tested. The relative densities and moisture descriptions indicated on the test pit logs are interpretive descriptions based on the conditions observed during excavation. The compaction of test pit backfill was not in the scope of our services. Loose soil will therefore be found in the area of the test pits. If this presents a problem, the backfill will need to be removed and replaced with structural fill during construction. CONCLUSIONS AND RECOMMENDATIONS GENERAL THIS SECTION CONTAINS A SUMMARY OF OUR STUDY AND FINDINGS FOR THE PURPOSES OF A GENERAL OVERVIEW ONLY. MORE SPECIFIC RECOMMENDATIONS AND CONCLUSIONS ARE GEOTECH CONSULTANTS, INC. RAD Holdings, LLC May 27, 2014 JN 14177 Pago 3 CONTAINED IN THE REMAINDER OF THIS REPORT. ANY PARTY REL YING ON THIS REPORT SHOULD READ THE ENTIRE DOCUMENT. The test pits conducted for this study encountered medium-dense silty sand with gravel that will provide adequate support to the proposed residences and pavements. The test pits found suitable bearing soils at a depth of 2 to 3 feet. The silty soils will be susceptible to disturbance and softening in wet conditions, As a result, it would be prudent to protect footing subgrades with a thin layer of crushed rock, If foundations are constructed within the footprint of the existing basements, it will be important to verify that suitable native bearing soils are first exposed. This usually requires removal of the foundations and slabs. We anticipate that perched water may be encountered in the sidewalls of the proposed stormwater detention pond excavation. This could cause erosion and instability near the seepage zone. We recommend that the portion of the pond more than 3 feet below the existing surface be armored with a one-foot-thickness of 2-to 4-inch rock spalls to reduce the potential for erosion of the pond sides. The proposed excavations for the east sides of the two access driveways will be within 10 feet of adjacent residences. To avoid impacting those residences, no excavation should extend below a 1.5: 1 (H:V) inclination extending outward from the base of the residence foundations. Shallow perched groundwater may result in seepage entering crawl spaces and/or basements under the planned houses. In addition to footing drains and free-draining wall backfill, drainage should be provided beneath the houses. This typically consists of a 6-to 9-inch layer of free- draining gravel below the vapor retarder, with perforated pipes buried in the gravel on 15-to 20-foot spacing. This underdrainage can be connected to the same outlet as the footing drains. The erosion control measures needed during the site development will depend heavily on the weather conditions that are encountered. We anticipate that a silt fence will be needed around the downslope sides of any cleared areas. Existing pavements, ground cover, and landscaping should be left in place wherever possible to minimize the amount of exposed soil. Rocked staging areas and construction access roads should be provided to reduce the amount of soil or mud carried off the property by trucks and equipment. Wherever possible, the access roads should follow the alignment of planned pavements. Trucks should not be allowed to drive off of the rock-covered areas. Cut slopes and soil stockpiles should be covered with plastic during wet weather. Following clearing or rough grading, it may be necessary to mulch or hydroseed bare areas that will not be immediately covered with landscaping or an impervious surface. On most construction projects, it is necessary to periodically maintain or modify temporary erosion control measures to address specific site and weather conditions. The on-site soil and groundwater conditions are not suitable for infiltration of runoff from impervious surfaces. This includes avoiding using drywells for downspout runoff. The drainage and/or waterproofing recommendations presented in this report are intended only to prevent active seepage from flowing through concrete walls or slabs. Even in the absence of active seepage into and beneath structures, water vapor can migrate through walls, slabs, and floors from the surrounding soil, and can even be transmitted from slabs and foundation walls due to the concrete curing process. Water vapor also results from occupant uses, such as cooking and bathing. Excessive water vapor trapped within structures can result in a variety of undesirable GEOTECH CONSULTANTS, INC. RAD Holdings, LLC lvlay 27, 2014 JN14177 Page 4 conditions, including, but not limited to, moisture problems with flooring systems, excessively moist air within occupied areas, and the growth of molds, fungi, and other biological organisms that may be harmful to the health of the occupants. The designer or architect must consider the potential vapor sources and likely occupant uses, and provide sufficient ventilation, either passive or mechanical, to prevent a build up of excessive water vapor within the planned structure. Geotech Consultants, Inc. should be allowed to review the final development plans to verify that the recommendations presented in this report are adequately addressed in the design. Such a plan review would be additional work beyond the current scope of work for this study, and it may include revisions to our recommendations to accommodate site, development, and geotechnical constraints that become more evident during the review process. We recommend including this report, in its entirety, in the project contract documents. This report should also be provided to any future property owners so they will be aware of our findings and recommendations. SEISMIC CONSIDERATIONS In accordance with the International Building Code (IBC), the site class within 100 feet of the ground surface is best represented by Site Class Type C (Very Dense Soil and Soft Rock). The site soils are not susceptible to seismic liquefaction because of their dense nature. CONVENTIONAL FOUNDA T/ONS The proposed structure can be supported on conventional continuous and spread footings bearing on undisturbed, medium-dense, native soil, or on structural fill placed above this competent native soil. See the section entitled General Earthwork and Structural Fill for recommendations regarding the placement and compaction of structural fill beneath structures. Adequate compaction of structural fill should be verified with frequent density testing during fill placement. Prior to placing structural fill beneath foundations, the excavation should be observed by the geotechnical engineer to document that adequate bearing soils have been exposed. We recommend that continuous and individual spread footings have minimum widths of 12 and 16 inches, respectively. Exterior footings should also be bottomed at least 18 inches below the lowest adjacent finish ground surface for protection against frost and erosion. The local building codes should be reviewed to determine if different footing widths or embedment depths are required. Footing subgrades must be cleaned of loose or disturbed soil prior to pouring concrete. Depending upon site and equipment constraints, this may require removing the disturbed soil by hand. An allowable bearing pressure of 2,500 pounds per square foot (psi) is appropriate for footings supported on competent native soil. A one-third increase in this design bearing pressure may be used when considering short-term wind or seismic loads. For the above design criteria, it is anticipated that the total post-construction settlement of footings founded on competent native soil, or on structural fill up to 5 feet in thickness, will be about one-inch, with differential settlements on the order of one-half-inch in a distance of 30 feet along a continuous footing with a uniform load. Lateral loads due to wind or seismic forces may be resisted by friction between the foundation and the bearing soil, or by passive earth pressure acting on the vertical, embedded portions of the foundation. For the latter condition, the foundation must be either poured directly against relatively GEOTECH CONSULTANTS. INC. RAD Holdings, LLC lvlay 27, 2014 JN 14177 Page 5 level, undisturbed soil or be surrounded by level, well-compacted fill. We recommend using the following ultimate values for the foundation's resistance to lateral loading: Coefficient of Friction 0.45 Passive Earth Pressure 350 pcf Where: {i) pcf is pounds per cubic foot, and (il) passive earth pressure is computed using the equivalent fluid density. If the ground in front of a foundation is loose or sloping, the passive earth pressure given above will not be appropriate. We recommend maintaining a safety factor of at least 1.5 for the foundation's resistance to lateral loading, when using the above ultimate values. FOUNDATION AND RETAINING WALLS Retaining walls backfilled on only one side should be designed to resist the lateral earth pressures imposed by the soil they retain. The following recommended parameters are for walls that restrain level backfill: Passive Earth Pressure 350 pc/ ,I Coefficient of Friction 0.45 'e------------+--------1 ii Soil Unit Weight 130 pcf Where: (i} pcf is pounds per cubic foot, and (ll) active and passive earth pressures are computed using the equivalent fluid pressures. "' For a restrained wall that cannot deflect at least 0.002 times its height, a uniform lateral pressure equal to 10 psftimes the height of the wall should be added to the above active equivalent fluid pressure. The design values given above do not include the effects of any hydrostatic pressures behind the walls and assume that no surcharges, such as those caused by slopes, vehicles, or adjacent foundations will be exerted on the walls. If these conditions exist, those pressures should be added to the above lateral soil pressures. Where sloping backfill is desired behind the walls, we will need to be given the wall dimensions and the slope of the backfill in order to provide the appropriate design earth pressures. The surcharge due to traffic loads behind a wall can typically be accounted for by adding a uniform pressure equal to 2 feet multiplied by the above active fluid density. Heavy construction equipment should not be operated behind retaining and foundation walls within a distance equal to the height of a wall, unless the walls are designed for the additional lateral pressures resulting from the equipment. The values given above are to be used to design only permanent foundation and retaining walls that are to be backfilled, such as conventional walls constructed of reinforced concrete or masonry. It is not appropriate to use the above earth pressures and soil unit weight to back-calcL1late soil strength parameters for design of other types of retaining walls, such as soldier pile, reinforced GEOTECH CONSULT ANTS, INC. RAD Holdings, LL C May 27, 2014 JN 14177 Page 6 earth, modular or soil nail walls. We can assist with design of these types of walls, if desired. The passive pressure given is appropriate only for a shear key poured directly against undisturbed native soil, or for the depth of level, well-compacted fill placed in front of a retaining or foundation wall. The values for friction and passive resistance are ultimate values and do not include a safety factor. We recommend a safety factor of at least 1.5 for overturning and sliding, when using the above values to design the walls. Restrained wall soil parameters should be utilized for a distance of 1.5 times the wall height from corners or bends in the walls. This is intended to reduce the amount of cracking that can occur where a wall is restrained by a corner. Wall Pressures Due to Seismic Forces The surcharge wall loads that could be imposed by the design earthquake can be modeled by adding a uniform lateral pressure to the above-recommended active pressure. The recommended surcharge pressure is 7H pounds per square foot (psf), where H is the design retention height of the wall. Using this increased pressure, the safety factor against sliding and overturning can be reduced to 1.2 for the seismic analysis. Retaining Waif Backfill and Waterproofing Backfill placed behind retaining or foundation walls should be coarse, free-draining structural fill containing no organics. This backfill should contain no more than 5 percent silt or clay particles and have no gravel greater than 4 inches in diameter. The percentage of particles passing the No. 4 sieve should be between 25 and 70 percent. The native soils are not free-draining. If they are used as compacted wall backfill, a minimum 12-inch thickness of free-draining gravel should be placed against the wall. The later section entitled Drainage Considerations should also be reviewed for recommendations related to subsurface drainage behind foundation and retaining walls. The purpose of these backfill requirements is to ensure that the design criteria for a retaining wall are not exceeded because of a build-up of hydrostatic pressure behind the wall. Also, subsurface drainage systems are not intended to handle large volumes of water from surface runoff. The top 12 to 18 inches of the backfill should consist of a compacted, relatively impermeable soil or topsoil, or the surface should be paved. The ground surface must also slope away from backfilled walls to reduce the potential for surface water to percolate into the backfill. Water percolating through pervious surfaces (pavers, gravel, permeable pavement, eel.) must also be preve.nted from flowing toward walls or into the backfill zone. The compacted subgrade below pervious surfaces and any associated drainage layer should therefore be sloped away. Alternatively, a membrane and subsurface collection system could be provided below a pervious surface. It is critical that the wall backfill be placed in lifts and be properly compacted, in order for the above-recommended design earth pressures to be appropriate. The wall design criteria assume that the backfill will be well-compacted in lifts no thicker than 12 inches. The compaction of backfill near the walls should be accomplished with hand-operated equipment to prevent the walls from being overloaded by the higher soil forces that occur during compaction. The section entitled General Earthwork and Structural Fill contains additional recommendations regarding the placement and compaction of structural fill behind retaining and foundation walls. The above recommendations are not intended to waterproof below-grade walls, or to prevent the formation of mold, mildew or fungi in interior spaces. Over time, the GEOTECH CONSULTANTS, INC. RAD Holdings, LLC May 27, 2014 JN 14177 Page 7 performance of subsurface drainage systems can degrade, subsurface groundwater flow patterns can change, and utilities can break or develop leaks. Therefore, waterproofing should be provided where future seepage through the walls is not acceptable. This typically includes limiting cold-joints and wall penetrations, and using bentonite panels or membranes on the outside of the walls. There are a variety of different waterproofing materials and systems, which should be installed by an experienced contractor familiar with the anticipated construction and subsurface conditions. Applying a thin coat of asphalt emulsion to the outside face of a wall is not considered waterproofing, and will only help to reduce moisture generated from water vapor or capillary action from seeping through the concrete. As with any project, adequate ventilation of basement and crawl space areas is important to prevent a build up of water vapor that is commonly transmitted through concrete walls from the surrounding soil, even when seepage is not present. This is appropriate even when waterproofing is applied to the outside of foundation and retaining walls. We recommend that you contact an experienced envelope consultant if detailed recommendations or specifications related to waterproofing design, or minimizing the potential for infestations of mold and mildew are desired. SLABS-ON-GRADE The building floors can be constructed as slabs-on-grade atop competent native soil or on structural fill. The subgrade soil must be in a firm, non-yielding condition at the time of slab construction or underslab fill placement. Any soft areas encountered should be excavated and replaced with select, imported structural fill. The General section should be reviewed for underdrainage recommendations. Even where the exposed soils appear dry, water vapor will tend to naturally migrate upward through the soil to the new constructed space above it. This can affect moisture-sensitive flooring, cause imperfections or damage to the slab, or simply allow excessive water vapor into the space above the slab. All interior slabs-on-grade should be underlain by a capillary break drainage layer consisting of a minimum 4-inch thickness of clean gravel or crushed rock that has a fines content (percent passing the No. 200 sieve) of less than 3 percent and a sand content (percent passing the No. 4 sieve) of no more than 1 O percent. Pea gravel or crushed rock are typically used for this layer. As noted by the American Concrete Institute (ACI) in the Guides for Concrete Floor and Slab Structures, proper moisture protection is desirable immediately below any on-grade slab that will be covered by tile, wood, carpet, impermeable floor coverings, or any moisture-sensitive equipment or products. ACI also notes that vapor retarders such as 6-mil plastic sheeting have been used in the past, but are now recommending a minimum 1 O-m1I thickness for better durability and long term performance. A vapor retarder is defined as a material with a permeance of less than 0.3 perms, as determined by ASTM E 96. It is possible that concrete admixtures may meet this specification, although the manufacturers of the admixtures should be consulted. Where vapor retarders are used under slabs, their edges should overlap by at least 6 inches and be sealed with adhesive tape. The sheeting should extend to the foundation walls for maximum vapor protection. If no potential for vapor passage through the slab is desired, a vapor barrier should be used. A vapor barrier, as defined by ACI, is a product with a water transmission rate of 0.01 perms when tested in accordance with ASTM E 96. Reinforced membranes having sealed overlaps can meet this requirement. GEOTECH CONSULTANTS, INC. RAD Holdings, LLC May 27, 2014 EXCAVATIONS AND SLOPES JN 14177 Page 8 Excavation slopes should not exceed the limits specified in local, state, and national government safety regulations. Temporary cuts to a depth of about 4 feet may be attempted vertically in unsaturated soil, if there are no indications of slope instability. However, vertical cuts should not be made near property boundaries, or existing utilities and structures. Based upon Washington Administrative Code (WAC) 296, Part N, the soil at the subject site would generally be classified as Type B. Therefore, temporary cut slopes greater than 4 feet in height should not be excavated at an inclination steeper than 1 :1 (Horizontal:Vertical), extending continuously between the top and the bottom of a cut. The above-recommended temporary slope inclination is based on the conditions exposed in our explorations, and on what has been successful at other sites with similar soil conditions. It is possible that variations in soil and groundwater conditions will require modifications to the inclination at which temporary slopes can stand. Temporary cuts are those that will remain unsupported for a relatively short duration to allow for the construction of foundations, retaining walls, or utilities. Temporary cut slopes should be protected with plastic sheeting during wet weather. It is also important that surface runoff be directed away from the top of temporary slope cuts. Cut slopes should also be backfilled or retained as soon as possible to reduce the potential for instability. Please note that sand or loose soil can cave suddenly and without warning. Excavation, foundation, and utility contractors should be made especially aware of this potential danger. These recommendations may need to be modified if the area near the potential cuts has been disturbed in the past by utility installation, or if settlement-sensitive utilities are located nearby. All permanent cuts into native soil should be inclined no steeper than 2:1 (H:V). Permanent cut slopes encountering groundwater may require gravel armoring. Compacted fill slopes should not be constructed with an inclination greater than 2:1 (H:V). To reduce the potential for shallow sloughing, fill must be compacted to the face of these slopes. This can be accomplished by overbuilding the compacted fill and then trimming it back to its final inclination. Adequate compaction of the slope face is important for long-term stability and is necessary to prevent excessive settlement of patios, slabs, foundations, or other improvements that may be placed near the edge of the slope. Water should not be allowed to flow uncontrolled over the top of any temporary or permanent slope. All permanently exposed slopes should be seeded with an appropriate species of vegetation to reduce erosion and improve the stability of the surficial layer of soil. DRAINAGE CONSIDERATIONS Footing drains should be used where (1) crawl spaces or basements will be below a structure, (2) a slab is below the outside grade, or (3) the outside grade does not slope downward from a building. Drains should also be placed at the base of all earth-retaining walls. These drains should be surrounded by at least 6 inches of 1-inch-minus, washed rock that is encircled with non-woven, geotextile filter fabric (Mirafi 140N, Supac 4NP, or similar material). At its highest point, a perforated pipe invert should be at least 6 inches below the bottom of a slab floor or the level of a crawl space. The discharge pipe for subsurface drains shquld be sloped for flow to the outlet point. Roof and surface water drains must not discharge into the foundation drain system. A typical drain detail is attached to this report as Plate 5. For the best long-term performance, perforated PVC pipe is recommended for all subsurface drains. GEOTECH CONSULTANTS, INC. RAD Holdings, LLC May 27, 2014 JN 14177 Page 9 As a minimum, a vapor retarder, as defined in the Slabs-On-Grade section, should be provided in any crawl space area to limit the transmission of water vapor from the underlying soils. Crawl space grades are sometimes left near the elevation of the bottom of the footings. As a result, an outlet drain is recommended for all crawl spaces to prevent an accumulation of any water that may bypass the footing drains. Providing even a few inches of free draining gravel underneath the vapor retarder limits the potential for seepage to build up on top of the vapor retarder. Groundwater was observed during our field work. If seepage is encountered in an excavation, it should be drained from the site by directing it through drainage ditches, perforated pipe, or French drains, or by pumping it from sumps interconnected by shallow connector trenches at the bottom of the excavation. Final site grading in areas adjacent to buildings should slope away at least 2 percent, except where the area is paved. Surface drains should be provided where necessary to prevent ponding of water behind foundation or retaining walls. Drainage measures on multi-lot developments sometimes have to be modified or upgraded to address post-grading conditions. A discussion of grading and drainage related to pervious surfaces near walls and structures is contained in the Foundation and Retaining Walls section. PAVEMENT AREAS The pavement section may be supported on competent, native soil or on structural fill compacted to a 95 percent density. The pavement subgrade must be in a stable, non-yielding condition at the time of paving. Granular structural fill or geotextile fabric may be needed to stabilize soft, wet, or unstable areas. To evaluate pavement subgrade strength, we recommend that a proof roll be completed with a loaded dump truck immediately before paving. In most instances where unstable subgrade conditions are encountered, an additional 12 inches of granular structural fill will stabilize the subgrade, except for very soft areas where additional fill could be required. The subgrade should be evaluated by Geotech Consultants, Inc., after the site is stripped and cut to grade. Recommendations for the compaction of structural fill beneath pavements are given in the section entitled General Earthwork and Structural Fill. The performance of site pavements is directly related to the strength and stability of the underlying subgrade. The pavement for lightly loaded traffic and parking areas should consist of 2 inches of asphalt concrete (AC) over 4 inches of crushed rock base (CRB) or 3 inches of asphalt-treated base (ATB). We recommend providing heavily loaded areas with 3 inches of AC over 6 inches of CRB or 4 inches of ATB. Heavily loaded areas are typically main driveways, dumpster sites, or areas with truck traffic. Increased maintenance and more frequent repairs should be expected if thinner pavement sections are used. The pavement section recommendations and guidelines presented in this report are based on our experience in the area and on what has been successful in similar situations. As with any pavements, some maintenance and repair of limited areas can be expected as the pavement ages. Cracks in the pavement should be sealed as soon as possible after they become evident, in order to reduce the potential for degradation of the subgrade from infiltration of surface water. For the same reason, it is also prudent to seal the surface of the pavement after it has been in use for several years. To provide for a design without the need for any maintenance or repair would be uneconomical. GEOTECH CONSULTANTS, INC. RAD Holdings, LLC May 27, 2014 GENERAL EARTHWORK AND STRUCTURAL FILL JN 14177 Page 10 All building and pavement areas should be stripped of surface vegetation, topsoil, organic soil, and other deleterious material. It is important that existing foundations be removed before site development. The stripped or removed materials should not be mixed with any materials to be used as structural fill, but they could be used in non-structural areas, such as landscape beds. Structural fill is defined as any fill, including utility backfill, placed under, or close to, a building, behind permanent retaining or foundation walls, or in other areas where the underlying soil needs to support loads. All structural fill should be placed in horizontal lifts with a moisture content at, or near, the optimum moisture content. The optimum moisture content is that moisture content that results in the greatest compacted dry density. The moisture content of fill is very important and must be closely controlled during the filling and compaction process. The allowable thickness of the fill lift will depend on the material type selected, the compaction equipment used, and the number of passes made to compact the lift. The loose lift thickness should not exceed 12 inches. We recommend testing the fill as it is placed. If the fill is not sufficiently compacted, it can be recompacted before another lift is placed. This eliminates the need to remove the fill to achieve the required compaction. The following table presents recommended relative compactions for structural fill: , Beneath footings, slabs · or walkwa s '' Filled slopes and behind 90% Use of On-Site Soil retainin walls 95% for upper 12 inches of Beneath pavements subgrade; 90% below that level Where: Minimum Relative Compaction is the ratio, expressed in percentages, of the compacted dry density to the maximum dry density, as determined in accordance with ASTM Test Designation D 1557-91 (Modified Proctor). If grading activities take place during wet weather, or when the silty, on-site SOIi is wet, site preparation costs may be higher because of delays due to rain and the potential need to import granular fill. The on-site soil is generally silty and therefore moisture sensitive. Grading operations will be difficult during wet weather, or when the moisture content of this soil exceeds the optimum moisture content. Moisture-sensitive soil may also be susceptible to excessive softening and "pumping" from construction equipment, or even foot traffic, when the moisture content is greater than the optimum moisture content. It may be beneficial to protect subgrades with a layer of imported sand or crushed rock to limit disturbance from traffic. GEOTECH CONSULTANTS, INC. RAD Holdings, LLC May 27, 2014 JN 14177 Page 11 Structural fill that will be placed in wet weather should consist of a coarse, granular soil with a silt or clay content of no more than 5 percent. The percentage of particles passing the No. 200 sieve should be measured from that portion of soil passing the three-quarter-inch sieve. LIMITATIONS The conclusions and recommendations contained in this report are based on site conditions as they existed at the time of our exploration and assume that the soil and groundwater conditions encountered in the test pits are representative of subsurface conditions on the site. If the subsurface conditions encountered during construction are significantly different from those observed in our explorations, we should be advised at once so that we can review these conditions and reconsider our recommendations where necessary. Unanticipated conditions are commonly encountered on construction sites and cannot be fully anticipated by merely taking samples in test pits. Subsurface conditions can also vary between exploration locations. Such unexpected conditions frequently require making additional expenditures to attain a properly constructed project. It is recommended that the owner consider providing a contingency fund to accommodate such potential extra costs and risks. This is a standard recommendation for all projects. This report has been prepared for the exclusive use of RAD Holdings, LLC and its representatives for specific application to this project and site. Our conclusions and recommendations are professional opinions derived in accordance with our understanding of current local standards of practice, and within the scope of our services. No warranty is expressed or implied. The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences, or procedures, except as specifically described in our report for consideration in design. Our services also do not include assessing or minimizing the potential for biological hazards, such as mold, bacteria, mildew and fungi in either the existing or proposed site development. ADDITIONAL SERVICES Geotech Consultants, Inc. should be retained to provide geotechnical consultation, testing, and observation services during construction. This is to confirm that subsurface conditions are consistent with those indicated by our exploration, to evaluate whether earthwork and foundation construction activities comply with the general intent of the recommendations presented in this report, and to provide suggestions for design changes in the event subsurface conditions differ from those anticipated prior to the start of construction. However, our work would not include the supervision or direction of the actual work of the contractor and its employees or agents. Also, job and site safety, and dimensional measurements, will be the responsibility of the contractor. During the construction phase, we will provide geotechnical observation and testing services when requested by you or your representatives. Please be aware that we can only document site work we actually observe. It is still the responsibility of your contractor or on-site construction team to verify that our recommendations are being followed, whether we are present at the site or not. The following plates are attached to complete this report: Plate 1 Vicinity Map GEOTECH CONSULTA~TS, INC. RAD Holdings, LLC May 27, 2014 Plate 2 Plates 3 -4 Plate 5 Site Exploration Plan Test Pit Logs Typical Footing Drain Detail JN 14177 Page 12 We appreciate the opportunity to be of service on this project. Please contact us if you have any questions, or if we can be of further assistance. TRCIMRM: at Respectfully submitted, GEOTECH CONSULTANTS, INC. GEOTECH CONSULT;\NTS, INC. ~-, GEOTECI-1 CONSUITANTS, INC. ~-*' = ........ ==---~~ (Source: Microsoft Streets and Trips, 2004) VICINITY M.AP 3112 Talbot Road South Renton, Washington I Job No: I Date: I . 14177 May201~ I Plate: Legend: [:.iii Test pit location SITE EXPLORATION PLAN 3112 Talbot Road South Renton, Washington Job No: Date: Plate: 14177 Ma 2014 No Scale 2 5 10 5 10 TEST PIT 1 Description TOPSOIL Dark-brown silty SAND with occa-sional gravel, roots, and organics, fine to coarse-grained, moist, loose to medium-dense -becomes brown and medium-dense, with pieces of dense silt -decreased gravel content -becomes dense * Test Pit terminated at 8.8 feet on May 21, 2014. * No groundwater seepage was observed during excavation. * No caving observed during excavation. TEST PIT 2 Description TOPSOIL Rust-brown mottled gray SILT with sand, fine to medium-grained, non-plastic, moist, loose to medium-dense -Brown silty SAND with gravefand pieces of dense si~, fine to coarse-grained, moist, medium-dense -becomes dense * Test Pit terminated at 6.0 feet on May 21, 2014. * No groundwater seepage was observed during excavation. * No caving observed during excavation. ~-, ~~~11'!is~IN1l. ~~bs=~~~,_~.............,,-- TEST PIT LOG 3112 Talbot Road South Renton, Washington Job Logged by: Plate: 14177 TRC 3 5 10 5 10 TEST PIT 3 Description TOPSOIL -----------cc--~-~~~------~--- Rust-brown mottled gray silty SAI\JD with gravel, fine to coarse-grained, moist, loose -becomes brown and medium-dense -becomes dense * Test Pit terminated at 6,0 feet on May 21, 2014. • Slight groundwater seepage was observed at 3.0 feet during excavation. * No caving observed during excavation. TEST PIT 4 Description TOPSOIL •=~~1-------~~-~~ Rust-brown mottled gray silty SAND with gravel, fine to coarse-grained, moist, loose -becomes brown and medium-dense SM -becomes dense * Test Pit terminated at 6.0 feet on May 21, 2014. * No groundwater seepage was observed during excavation. * No caving observed during excavation. GEOTECH CONSULTANTS, INC. TEST PIT LOG 3112 Talbot Road South Renton, Washington ,,,, 1""~l;:=---c"""'""· ,::""'==""" ...... =,..... Job Date: Logged by: Plate: 14177 May2014 TRC 4 Slope backfill away from foundation. Provide surface drains where necessary. Backfill ( See text for r, requirements) 111 ) Tightline Roof Drain (Do not connect to footing drain) Washed Rock (7/8" min. size) Nonwoven Geotextile Filter Fabric NOTES: L__ 4" Perforated Hard PVC Pipe ( Invert at least 6 inches below slab or crawl space. Slope to drain to appropriate outfall. Place holes downward.) Vapor Retarder/Barrier and Capillary Break/Drainage Layer (Refer to Report text) (1) In crawl spaces, provide an outlet drain to prevent buildup of water that bypasses the perimeter footing drains. (2) Refer to report text for additional drainage, waterproofing, and slab considerations. GEOTECH CONSULTANTS, INC. FOOTING DRAIN DETAIL 3112 Talbot Road South Renton, Washington I Job No: I Date: . 14177 May 2014 I Plate: CRITICAL AREAS STUDY FOR RAD Holdings, LLC -3112 Talbot Road Tax Parcel No. 302305-9028 Acre Project #13039 Prepared By: Acre Environmental Consulting, LLC. 17715 28th Ave. NE Lake Forest Park, WA 98155 (206) 450-7746 For: RAD Holdings, LLC Attn. Rory Dees 6252 167'h Avenue SE Bellevue, WA 98006 September 4, 2013 TABLE OF CONTENTS INTRODUCTION AND BRIEF SITE DESCRIPTION METHODOLOGIES OF CRITICAL AREAS EVALUATION BOUNDARY DETERMINATION FINDINGS EXISTING FUNCTIONS AND VALUES ANALYSIS USE OF THIS REPORT REFERENCES ATIACHMENTS: 1. WETLAND DETERMINATION DATA FORMS (6 DATA POINTS ON-SITE) 2. CRITICAL AREAS MAP SHEET CAl.00 Acre Environmental Consulting, LLC Critical Areas Study for-RAD Holdings, LLC-Talbot Rd. Renton, WA 2 2 3 5 6 7 September 4, 2013 Page 1 INTRODUCTION AND BRIEF SITE DESCRIPTION On July 25, 2013 Acre Environmental Consulting, LLC visited the subject property located at 3112 Talbot Road in the City of Renton, Washington. The purpose of this site visit was to assess and locate regulated critical areas on and adjacent to the subject site. The site is further located as a portion of Section 30, Township 23N, Range OSE, W.M. The tax parcel number for this property is 302305-9028. Per the King County Assessor's office, the site encompasses approximately 2.3-acres. Surrounding land use is comprised of single family residences. Access to this site is from the west via a gravel driveway that leads from Talbot Road. The subject property has a west aspect slope with the western portion occupied by two single-family residences and maintained lawn. The eastern portion of the site is comprised of established forest with a Category 2 wetland that extends off-site to the east and south. In the City of Renton, Category 2 wetlands receive a SO-foot standard buffer measured from the delineated wetland edge. METHODOLOGIES OF CRITICAL AREAS EVALUATION In July of 2013, Acre Environmental Consulting, LLC conducted a site visit to locate and verify wetlands and streams occurring on and adjacent to the subject site. The methods used for delineating, classifying, and rating the wetlands and streams in the project area are consistent with current Federal, State, and City of Renton requirements. At the time of our July 25, 2013 site investigation, the weather was sunny with a temperature of 68 degrees Fahrenheit. Acre Environmental Consulting, LLC used the routine methodologies described in the Washington State Wetlands Identification and Delineation Manual (Washington State Department of Ecology Publication #96-94, March 1997) to make a determination regarding regulated wetlands. In addition, Acre Environmental Consulting, LLC evaluated the site using the U.S. Army Corps of Engineers Wetland Delineation Manual produced in 1987 and the U.S. Army Corps of Engineers Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region produced in May 2010 (hereinafter referred to as "the Corps Regional Supplement"). The Corps Regional Supplement is designed for concurrent use with the 1987 Corps Wetland Delineation Manual and all subsequent versions. The 2010 Regional Supplement provides technical guidance and procedures for identifying and delineating wetlands that may be subject to regulatory jurisdiction under Section 404 of the Clean Water Act. Where differences in the two documents occur, the Corps Regional Supplement takes precedence over the Corps Manual for applications in the Western Mountains, Valleys, and Coast Region. According to the federal and state methodologies described above, identification of wetlands is based on a three-factor approach involving indicators of hydrophytic vegetation, hydric soils, Acre Environmental Consulting, LLC Critical Areas Study for -RAD Holdings, LLC -Talbot Rd. Renton, WA September 4, 2013 Page 2 and the presence or evidence of persistent hydrology. Except where noted in the manuals, the three-factor approach discussed above requires positive indicators of hydrophytic vegetation, hydric soils, and wetland hydrology, to make a determination that an area is a regulated wetland. Using the aforementioned manuals, the procedure for making a wetland determination is as follows: 1.) Examination of the site for hydrophytic vegetation (species present/percent cover); 2.) Examination for the presence of hydric soils in areas where hydrophytic vegetation is present; and 3.) The final step is determining if wetland hydrology exists in the area examined under the first two steps. Per industry standards, Acre Environmental Consulting, LLC examined the entire project site. Per current City of Renton requirements, Acre Environmental Consulting, LLC also assessed adjacent properties within 300 feet of the proposed project limits, to the maximum extent possible without entering adjacent properties. While a detailed assessment of Critical Areas on adjacent properties was not possible due to the lack of legal access, Acre Environmental Consulting, LLC conducted a review of all available information to assess the presence of off-site Critical Areas within 300 feet of the subject site. This review is necessary to determine if any regulated Critical Areas exist off-site which would cause associated protective buffers to extend onto the property and affect the development proposal. In addition to on-site field reviews, Acre Environmental Consulting, LLC examined aerial photographs and topographical data (elevation contours) on King County's interactive mapping system (iMAP). Soil survey maps produced by the Natural Resources Conservation Service (NRCS), National Wetlands Inventory (NWI) maps produced by the U.S. Fish and Wildlife Service (USFWS), SalmonScape fish distribution maps produced by the Washington Department of Fish and Wildlife (WDFW), and StreamNet fish distribution maps produced by Pacific States Marine Fisheries Commission were also evaluated by Acre Environmental Consulting, LLC as part of this project consultation. BOUNDARY DETERMINATION FINDINGS Wetlands were classified according to the U.S. Fish and Wildlife Service (USFWS) Cowardin system Classification of Wetlands and Deepwater Habitats of the United States (Cowardin et al., 1979) and rated, by categories, according to the City of Renton Municipal Code Section 4-3-050 (Critical Areas Regulations). Buffers are also determined by this chapter. Acre Environmental Consulting, LLC Critical Areas Study for-RAD Holdings, LLC-Talbot Rd. Renton, WA September 4, 2013 Page 3 Wetland A Cowardin: Palustrine, Forested wetland, Broad-leaved Deciduous, Seasonally Flooded/Saturated (PF01E) City of Renton Rating: Category 2, 50' Buffer This wetland is located in the eastern portion of the subject site and extends off-site to the east and south. This wetland does not meet the criteria for a Category 1 wetland in that it does not contain threatened or endangered species or provide habitat for these species, is less than ten acres in size with one class of vegetation (forested), does not contain permanent open water, and does not contain plant associations of infrequent occurrence. This wetland does not meet the criteria for a Category 3 wetland because it is not severely disturbed. This wetland exhibits a minimum of human related physical alteration, and therefore, meets the criteria for a Category 2 wetland. In the City of Renton, Category 2 wetlands receive SO-foot standard buffers from their delineated edge. Vegetation in this wetland is represented by a canopy of Oregon ash (Fraxinus /atifolio, FacW) and black cottonwood (Populus balsamifera, Fae), with and understory comprised of red osier dogwood (Camus sericea, FacW), hardhack (Spiraea doug/asii, FacW), Himalayan blackberry (Rubus armeniacus, FacU), reed canarygrass (Phalaris arundinacea, FacW), creeping buttercup (Ranunculus repens, FacW), and sword fern (Polystichum munitum, FacU) on hummocks. Soils in this wetland have a Munsell color of very dark greyish brown (10YR 3/2) with redoximorphic features of brown (lOYR 4/3), and a texture of silt loam from Oto 18 inches below the surface. Soils in this wetland were saturated at 12 inches below the surface during our July 2013 site visit. Non -Wetland Vegetation in the western portion of the property is comprised of maintained lawn represented by tall fescue (Schedonorus arundinaceu, Fae), blue wildrye (Elymus g/aucus, FacU), hairy Cat's- ear (Hypochaeris radicata, FacU), velvetgrass (Holcus lanotus, Fae), colonial bentgrass (Agrostis tenuis, Fae), creeping buttercup (Ranunculus repens, Fae), and white clover (Trifo/ium repens, Fae). The lawn is interspersed with patches of Himalayan blackberry (Rubus armeniacus, FacU) and scattered trees, including big leaf maple (Acer macrophyllum, FacU) and Oregon ash (Fraxinus latifo/io, FacW). Vegetation in the eastern part of the site is forested, represented by a canopy of big leaf maple (Acer mocrophyllum, FacU), Oregon ash (Fraxinus /atifo/ia, FacW), and western red cedar (Thuja plicota, Fae), with snowberry (Symphoricarpos a/bus, FacU), osoberry (Oemleria cerasiformis, FacU), Himalayan blackberry (Rubus armeniacus, FacU), hazelnut (Cory/us cornuta, FacU), Oceanspray (Holodiscus discolor, FacU), thimbelberry (Rubus porviflorus, FacU), dewberry (Rubus ursinus, FacU), and sword fern (Polystichum munitum, FacU), in the understory. Typical soils in the non-wetland portions of the site have a Munsell Acre Environmental Consulting, LLC Critical Areas Study for-RAD Holdings, LLC -Talbot Rd. Renton, WA September 4, 2013 Page 4 color of very dark greyish brown (lOYR 3/2), with redoximorphic features of brown (lOYR 4/3), and a texture of silt loam from O to 18 inches below the surface. Soils in the non-wetland portions of this property were dry during our July 2013 site visit. NATURAL RESOURCE CONSERVATION SERVICE SOILS DESCRIPTION: The Natural Resources Conservation Service (NRCS) mapped the subject property as being underlain by Alderwood gravelly sandy loam, 6 to 15 percent slopes. The NRCS describes Alderwood gravelly sandy loam, 6 to 15 percent slopes as rolling with irregularly shaped areas ranging from 10 to about 600 acres in size. The A horizon ranges from very dark brown to dark brown. The B horizon is dark brown, grayish brown, and dark yellowish brown. Permeability is moderately rapid in the surface layer and subsoil and very slow in the substratum. Available water capacity is described as low. Included within this soil unit are the poorly drained Norma, Bellingham, Seattle, Tukwila, Shalcar soils, and Alderwood soils that have slopes more gentle or steeper than 6 to 15 percent. Included soil units make up no more than 30 percent of the total acreage. EXISTING FUNCTIONS AND VALUES ANALYSIS The methodologies for this functions and values analysis are based on professional opinion developed through past field analyses and interpretations. This assessment pertains specifically to the subject wetland, but is typical for assessments of similar systems throughout western Washington. The three main functions provided by wetlands include water quality, stormwater / hydrologic control, and wildlife habitat. The wetland and buffer on the subject site are forested, dominated by native trees and shrubs. Wetlands in western Washington often contain necessary wildlife habitat resources such as food, water, thermal cover, and hiding cover in close proximity. The subject wetland and buffer likely provide a moderate level of habitat for a variety of wildlife species. During our site visit, Acre Environmental Consulting, LLC observed an American Crow (Corvus brachyrhynchos), a song sparrow (Melospiza melodia), a black-capped chickadee (Poecile atricapillus), and evidence of a common raccoon (Procyon lotor), using the subject site. Due to its vegetative structure, the subject wetland provides habitat for use by terrestrial wildlife species including birds and mammals. The wetland and associated buffer provide protected habitat, which becomes increasingly important as areas become further populated with humans and habitat areas become fragmented. Habitat fragmentation and isolation from other resources resulting from the surrounding development serves to limit the habitat values that the subject wetland and buffer provide for wildlife. The established vegetation within the wetland and associated buffer on this site serves to Acre Environmental Consulting, LLC Critical Areas Study for-RAD Holdings, LLC-Talbot Rd. Renton, WA September 4, 2013 Page 5 intercept rain fall before it strikes the soil, thereby reducing erosion and improving water quality. Furthermore, the dense vegetation and adsorbent soils serve to trap sediment and pollutants and provide increased water quality functions that aid in a reduction of sediment which results in cleaner water leaving the site. USE OF THIS REPORT This Critical Areas Study is supplied to Rad Holdings, LLC as a means of determining whether any wetlands, streams, and/or fish and wildlife habitats regulated by the City of Renton Critical Areas Regulations exist on, or within 300 feet of the site. This report is intended to provide information deemed relevant in the applicant's attempt to comply with the regulations currently in effect. The work for this report has conformed to the standard of care employed by professional ecologists in the Pacific Northwest. No other representation or warranty is made concerning the work or this report. This report is based largely on readily observable conditions and, to a lesser extent, on readily ascertainable conditions. No attempt has been made to determine hidden or concealed conditions. If such conditions arise, the information contained in this report may change based upon those conditions. Please note that Acre Environmental Consulting, LLC did not provide detailed analysis of other permitting requirements not discussed in this report (i.e. structural, drainage, geotechnical, or engineering requirements). The laws applicable to Critical Areas are subject to varying interpretations. While Acre Environmental Consulting, LLC upheld professional industry standards when completing this review, the information included in this report does not guarantee approval by any federal, state, and/or local permitting agencies. Therefore, all work on this property shall not commence until permits have been obtained from all applicable agencies. If there are any questions regarding this report, please contact me at 206.450.7746. Acre Environmental Consulting, LLC. Louis Emenhiser Owner/ Principal Wetland Ecologist Professional Wetland Scientist #1680 Acre Environmental Consulting, LLC Critical Areas Study for-RAD Holdings, LLC -Talbot Rd. Renton, WA September 4, 2013 Page 6 REFERENCES Cowardin, et al, 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S.D.I. Fish and Wildlife Service. FWS/OBS-79/31. December 1979. Environmental Laboratory. (1987). "Corps of Engineers Wetlands Delineation Manual," Technical Report Y-87-1, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Miss. Hruby, T. 2004. Washington State wetland rating system for western Washington -Revised. Washington State Department of Ecology Publication# 04-06-025. King County iMAP: Interactive Mapping Tool. Administered by the City of Kirkland GIS Center. http://www.kingcounty.gov/operations/gis/Maps/iMAP.aspx. Website last visited August 16, 2013. Lichv ar, R.W. 2013. The National Wetland Plant List: 2013 wetland ratings. Phy toneuron 2013- 49: 1-241. Renton Municipal Code. Section 4-3-050 (Critical Areas Regulations). Renton, Washington. SalmonScape. Interactive Mapping website administered by the Washington Department of Fish and Wildlife. http://wdfw.wa.gov/mapping/salmonscape/index.html. Website last visited on August 15, 2013. StreamNet. Fish Data for the Northwest. Administered by the Pacific States Marine Fisheries Commission. http://www.streamnet.org/. Website last visited on August 16, 2013. U.S. Army Corps of Engineers (2010). "Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0)," ERDC/EL TR- 10-3, U.S. Army Engineer Research and Development Center, Vicksburg, MS. U.S. Fish and Wildlife Service. National Wetlands Inventory Wetlands Mapper. http://107.20.228.18/Wetlands/WetlandsMapper.html#. Last updated July 8, 2013. Website last visited on August 16, 2013. Washington State Wetlands Identification and Delineation Manual. Washington State Department of Ecology. Publication #96-94. March 1997. Web Soil Survey. United States Department of Agriculture. Natural Resources Conservation Service. http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm. Website last visited on August 16, 2013. Acre Environmental Consulting, LLC Critical Areas Study for -RAD Holdings, LLC -Talbot Rd. Renton, WA September 4, 2013 Page 7 WETLAND DETERMINATION DATA FORM-Western Mountains, Valleys, and Coast Region Project/Site RAD Holdings, LLC Applicant/Owner: RAD Holdings, LLC City/County: King County/ Renton Sampling Date 07.25.13 -----------------State _W_A ___ Sampling Point _D_P_1 ___ _ lnvestigator(s): Louis Emenhiser Section, Township. Range· _:_S:_3:_0_:_,_Tc:2c3.N_:__:_, R_:__:_5E~, W"-'-.M"'--. ----------- Landform (hillslope, terrace. etc.): _T_e_rr_a_ce __________ Local relief (concave convex, none): _C_o_n_c_a_v_e _____ Slope(%) ~ Subregion (LRR): LRR-A Lat 47.4520 Long: _-_12_2_._20_7_6 _______ Datum ----- Soil Map Unit Name: Alderwood gravelly sandy loam, 6 to 15 percent slopes Are climatic/ hydrologic conditions on the site typical for this time of year? Yes __ {_ __ No NWI classification· _P_F_0:_1:_E=--------- (lf no, explain in Remarks.) Are Vegetation __ , Soil _____ , or Hydrology_ _ significantly disturbed? Are Vegetation __ , Soil_ _, or Hydrology ___ naturally problematic? Are "Normal Circumstances" present? Yes_ ./ _ No (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc . Hydrophytic Vegetation Present? Yes ./ No --Is the Sampled Area -- Hydric Soil Present? Yes -./ ~ No --./ within a Wetland? Yes No Wetland Hydrology Present? Yes ./ No --~----- Remarks· Wetland A VEGETATION -Use scientific names of plants. Absolute Dominant Indicator Dominance Test worksheet: Tree Stratum (Plot size: 30 meters I % Cover Species? Status Number of Dominant Species 1 Fraxinus latifolia 60 y FacW That Are OBL, FACW, or FAC 6 (A) 2 Populus balsamifera 30 y Fae Total Number of Dominant 3 Species Across All Strata: 7 (B) 4 90 -Total Cover Percent of Dominant Species 86 That Are OBL, FACW, or FAG: (A/B) Sapling/Shrub Stratum (Plot size: 10 meters I 1. Cornus alba 20 y FacW Prevalence Index worksheet: 2 Spiraea douglasii 20 y FacW Total% Cover of: MultiQly by: 3. Rubus armeniacus 10 y FacU OBL species 0 X 1 = 0 4. FACW species 160 x2= 320 5. FAG species 60 x3= 180 50 = Total Cover F AC U species 15 x4= 60 Herb Stratum (Plot size: 1 meter ) UPL species 0 X 5 = 0 1 Phalaris arundinacea 60 y Facw Column Totals: 235 (A) 560 (B) 2 Ranunculus repens 30 y Fae 3. Polystichum munitum 5 N FacU Prevalence Index -B/A -2.38 4. Hydrophytic Vegetation Indicators: 5. I Dominance Test is >50% - 6 I Prevalence Index is :53.0 1 7 Morphological Adaptations1 (Provide supporting 8 data in Remarks or on a separate sheet) Wetland Non-Vascular Plants -9 10 Problematic Hydrophytic Vegetation 1 (Explain) 11 1 lndicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 95 = Total Cover Wood'i Vine Stratum (Plot size ) 1 Hydrophytic 2 Vegetation I Present? Yes No ------= Total Cover % Bare Ground in Herb Stratum 5 Remarks US Army Corps of Engineers Western Mountains, Valleys, and Coast -Version 2.0 SOIL s amp 1ng p nt DP1 o, Profile Description: (Describe to the depth needed to document the-indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist} ______%__ Color (moist) ---2Q_~ LocL Text~ Remarks 0-18 10YR 312 95 10YR 413 5 C M silt loam --------- ------------ --------- --------- --------- --·· ------ -------- -------- 1T"ne: C=Concentration, O-Deoletion, RM-Reduced Matrix, CS-Covered or Coated Sand Grains. 2Location: PL -Pore Linina. M=Matrix Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric SoilsJ: -Histosol (A 1) Sandy Redox (S5) _ 2 cm Muck (A10) Histic Epipedon (A2) Stripped Matrix (S6) _ Red Parent Material (TF2) -Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) Other (Explain in Remarks) -Hydrogen Sulfide (A4) Loamy Gleyed Matrix {F2) -Depleted Below Dark Surtace {A11) Depleted Matrix (F3) Thick. Dark Surface {A 12) ./ Redox Dark Surtace (F6) 31ndicators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surtace (F7) wetland hydrology must be present. Sandy Gleyed Matrix (S4) Redox Depressions (FB) unless disturbed or problematic. Restrictive Layer (if present): Tyw Depth (inches): Hydric Soil Present? Yes ./ No Remarks HYDROLOGY Wetland Hydrology Indicators: Primat:Y Indicators (minimum of one reguired· check all that ai;:ii;:il~) Secondary Indicators (2 or more reguired) Surface Water (A 1) _ Water-Stained Leaves (89) (except MLRA _ Water-Stained Leaves (B9) (MLRA 1, 2, _ High Water Table (A2) 1, 2, 4A, and 4B) 4A, and 4B) ./ Saturation (A3) Salt Crust (B11) _ Drainage Patterns (810) Water Marks (B1) Aquatic Invertebrates (813) _ Dry-Season Water Table (C2) -Sediment Deposits (82) Hydrogen Sulfide Odor (C1) _ Saturation Visible on Aerial Imagery (C9) ___ Drift Deposits (B3) Oxidized Rhizospheres along Living Roots (C3) :!__ Geomorphic Position (02) Algal Mat or Crust (B4) Presence of Reduced Iron (C4) Shallow Aquitard (03) Iron Deposits (85) Recent Iron Reduction in Tilled Soils (C6) ./ FAC-Neutral Test (05) Surface Soil Cracks (86) Stunted or Stressed Plants (01) (LRR A) Raised Ant Mounds (06) (LRR A) -Inundation Visible on Aerial Imagery (87) _ Other (Explain in Remarks) Frost-Heave Hummocks (07) -Sparsely Vegetated Concave Surface (88) Field Observations: Surtace Water Present? Yes --No -./ -Depth (inches): Water Table Present? Yes ./ No Depth (inches): 15 -- Saturation Present? Yes ./ No Depth (inches)· 12 --··--Wetland Hydrology Present? Yes ./ No ------ (includes caoillarv frinael Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections). 1f available Remarks· US Army Corps of Engineers Western Mountains, Valleys, and Coast-Version 2.0 WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region ProJect1Site RAD Holdings. LLC Applicant/Owner. RAD Holdings, LLC lnvestigator(s): Louis Emenhiser City/County: King County/ Renton Sampling Date 07.25.13 State: WA Sampling Point: _:_Dc_P_2 ____ _ Section, Township, Range: _S'--3'--0-'-._T_2_:_3N--'-. R_5E--'-, W_.M_. __________ _ Landform (hills lope, terrace, etc.). _H_i_lls_lo~p_e __________ Local relief (concave, convex, none)· _C_o_n_v_e_x ____ _ Slope(%)~ Subregion (LRR) LRR-A Lat 47.4520 Long: _-_12_2_.2_0_7_9 _____ _ Datum ____ _ Soil Map Unit Name: Alderwood gravelly sandy loam, 6 to 15 percent slopes NWI classification: _________ _ Are climatic/ hydrologic conditions on the site typical for this time of year? Yes ____ {_ No _ (lfno, explain in Remarks.) Are Vegetation __ , Soil~ _, or Hydrology_ _ significantly disturbed? Are Vegetation __ , Soil_ _, or Hydrology ___ naturally problematic? Are "Normal Circumstances" present? Yes_ ./ _ No (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes --No -I -Is the Sampled Area Hydric Soil Present? Yes -I -No --within a Wetland? I Yes No Wetland Hydrology Present? Yes No I ---- ------ Remarks· Non-wetland west of Wetland A. VEGETATION -Use scientific names of plants. Absolute Dominant Indicator Dominance Test worksheet: Tree Stratum (Plot size: 30 meters ) % Cover Species? Status Number of Dominant Species 1. Acer macrophyllum 70 y FacU That Are OBL, FACW, or FAC: 1 (A) 2. Thuja plicata 20 y Fae Total Number of Dominant 3. Species Across All Strata 5 (B) 4. 90 Percent of Dominant Species 20 = Total Cover That Are OBL. FACW, or FAG (A/B) SaQling/Shrub Stratum (Plot size: 10 meters ) 1. Corylus cornuta 30 y FacU Prevalence Index worksheet: 2. Oemleria cerasiformis 30 y FacU Total % Cover of: MultiQ!Y. by_: 3. Rubus armeniacus 5 N FacU OBL species 0 X 1 = 0 4. FACW species 0 x2= 0 5 FAC species 20 x3= 60 65 = Total Cover F AC U species 205 x4= 820 Herb Stratum (Plot size: 1 meter ) UPL species 0 x5= 0 1. Polystichum munitum 60 y FacU Column Totals: 225 (A) 880 (B) 2 Rubus ursinus 10 N FacU 3. Prevalence Index =BIA= 3.91 4. Hydrophytic Vegetation Indicators: 5. -Dominance Test is >50% 6. Prevalence Index is ::;3_0 1 7. Morphological Adaptations 1 (Provide supporting data in Remarks or on a separate sheet) 8. Wetland Non-Vascular Plants, 9. 10. Problematic Hydrophytic Vegetation' (Explain) 11. Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 70 -Total Cover Woody_ Vine Stratum (Plot size: ) 1. Hydrophytic 2. Vegetation I Present? Yes No ---= Total Cover % Bare Ground in Herb Stratum 10 Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast -Version 2.0 SOIL Sampling Point: _D_P_2 __ _ ----- Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist} ___.'.&_ Color (moist) ___.'.&_ ~ Loc2 Texture Remarks 0-18 10YR 3/2 95 10YR 3/3 5 C M silt loam --------- --------- --------- --------- --------- --------- --------- --------- 1T"ne: c-concentration, o-oeoletion, RM-Reduced Matrix, CS-Covered or Coated Sand Grains. 2Location: PL -Pore Linina, M-Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils\ -Histosol (A 1) Sandy Redox (S5) _ 2 cm Muck (A 10) -Histic Epipedon (A2) Stripped Matrix (S6) Red Parent Material (TF2) -Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) Other (Explain in Remarks) -Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) -Depleted Below Dark Surface (A11) Depleted Matrix (F3) Thick Dark Surface (A12) ,/ Redox Dark Surface (F6) 3lndicators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surface (F?) wetland hydrology must be present, Sandy Gleyed Matrix (S4) Redox Depressions (F8) unless disturbed or problematic Restrictive Layer {if present): Type: Depth (inches): Hydric Soil Present? Yes ./ No Remarks HYDROLOGY Wetland Hydrology Indicators: PrimaQl Indicators (minimum of one reguired: check all that ag:1;;1ly:} Secondaty Indicators (2 or more reguired) Surface Water (A 1) _ Water-Stained Leaves (89) (except MLRA _ Water-Stained Leaves (89) (MLRA 1, 2, High Water Table (A2) 1, 2, 4A, and 4B) 4A, and 4B) Saturation (A3) Salt Crust (811) -Drainage Patterns (810) ----Water Marks (B1) Aquatic Invertebrates (813) Dry-Season Water Table (C2) _ Sediment Deposits (82) Hydrogen Sulfide Odor (C 1) -Saturation Visible on Aerial Imagery (C9) -Drift Deposits (B3) Oxidized Rhizospheres along Living Roots (C3) -Geomorphic Position (02) Algal Mat or Crust (B4) Presence of Reduced Iron (C4) -Shallow Aquitard (03) Iron Deposits (B5) Recent Iron Reduction in Tilled Soils (C6) FAG-Neutral Test (D5) -Surface Soil Cracks (B6) Stunted or Stressed Plants (01) (LRR A} Raised Ant Mounds (D6) (LRR A) -Inundation Visible on Aerial Imagery (B7) _ Other (Explain in Remarks) Frost-Heave Hummocks (D?) _ Sparsely Vegetated Concave Surface (88) Field Observations: Surface Water Present? Yes -·--No -,/ -Depth (inches): Water Table Present? Yes No ,/ Depth (inches): ---- Saturation Present? Yes No ,/ Depth (inches): Wetland Hydrology Present? Yes No ,/ ------- (includes caoillarv frinae/ Describe Recorded Data (stream gauge, monitoring well. aerial photos, previous inspections). if available Remarks· US Army Corps of Engineers Western Mountains, Valleys, and Coast-Version 2.0 WETLAND DETERMINATION DATA FORM-Western Mountains, Valleys, and Coast Region Project/Site RAD Holdings. LLC Applicant/Owner· RAD Holdings, LLC lnvestigator(s): Louis Emenhiser City/County: King County f Renton Sampling Date 07.25.13 State: WA Sampling Point _D_P_3 ____ _ Section, Township, Range _S_3_0_,_T_2_3N~, R_5E_,~W_.M_. __________ _ Landform (h1llslope, terrace. etc): _H_il_ls_lo~p_e __________ Local relief (concave, convex, none): _C_o_n_v_e_x _____ Slope(%):~ Subregion (LRR): _:L::__R_:_R_:-_:A_:_ ____________ Lat· 47.4519 Long -122.2085 Datum: ____ _ Soil Map Unit Name. Alderwood gravelly sandy loam, 6 to 15 percent slopes NWI classification Are climatic/ hydrologic conditions on the site typical for this time of year? Yes_ ./ _ No (If no. explain in Remarks.) Are Vegetation _ Soil _, or Hydrology_ _ significantly disturbed? Are "Normal Circumstances" present? Yes_ ./ _ No (lf needed, explain any answers in Remarks.) Are Vegetation __ . Soil_ _, or Hydrology ___ naturally problematic? SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc . Hydrophytic Vegetation Present? Yes --No -./ -ls the Sampled Area Hydric Soil Present? Yes No ./ ./ ----within a Wetland? Yes No Wetland Hydrology Present? Yes No ./ --------- Remarks Non-wetland on the forested slope. VEGETATION -Use scientific names of plants. Absolute Dominant Indicator Dominance Test worksheet: Tree Stratum (Plot size: 30 meters I % Cover Species? Status Number of Dominant Species 1 Acer macrophyllum 60 y FacU That Are OBL, FACW, or FAC: 1 (A) 2 Fraxinus latifolia 30 y FacW Total Number of Dominant 3. Species Across All Strata 6 (B) 4 90 Percent of Dominant Species 16 = Total Cover That Are OBL, FACW, or FAG (NB) Sai;i!ing/Shrub Stratum (Plot size: 10 meters I 1. Symphoricarpos albus 30 y FacU Prevalence Index worksheet: 2 Oemleria cerasiformis 20 y FacU Total % Cover of: Multii;ily by: 3. Rubus armeniacus 20 y FacU OBL species 0 X 1 = 0 4. Holodiscus discolor 10 N FacU FACW species 30 x2= 60 5. Rubus parviflorus 10 N FacU FAC species 0 x3= 0 90 -Total Cover FACU species 160 x4= 640 Herb Stratum (Plot size: 1 meter ) UPL species 0 x5= 0 1 Polystichum munitum 10 y FacU 190 700 (B) Column Totals: (A) 2. 3 Prevalence Index =BIA= 3.68 4. Hydrophytic Vegetation Indicators: 5. -Dominance Test is >50% 6. Prevalence Index is s3.01 7. Morphological Adaptations 1 (Provide supporting 8 data in Remarks or on a separate sheet) -Wetland Non-Vascular Plants' 9. 10. Problematic Hydrophytic Vegetation1 (Explain) 11. 1lndicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 10 -Total Cover Woody_ Vine Stratum (Plot size: I 1 Hydrophytic 2 Vegetation ./ Present? Yes No -------Total Cover % Bare Ground in Herb Stratum 5 Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast -Version 2.0 SOIL Sampling Paint _D_P_3 __ _ -- Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches} Color (moist} _____'.l&_ Color (moist) _____'.l&_ ~ Lacz Texture Remarks 0-18 10YR 3/2 100 silt loam --------- --------- --------- ------------ --------- --------- --------- --------- 1Tvne. c-concentration, O-Deoletion, RM-Reduced Matrix, CS-Covered or Coated Sand Grains. 2 Location: PL -Pore Linina, M-Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3 : -Histosol (A 1) Sandy Redox (S5) _ 2 cm Muck (A10) -Histic Epipedon (A2) Stripped Matrix (S6) _ Red Parent Material {TF2) -Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) Other (Explain in Remarks) Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) Depleted Below Dark Surface (A 11) Depleted Matrix (F3) Thick Dark Surface (A 12) Redox Dark Surface {F6) Jlndicators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surface (F7) wetland hydrology must be present Sandy Gleyed Matrix (S4) Redox Depressions (F8) unless disturbed or problematic. Restrictive Layer (if present): Type. Depth (inches): Hydric Soil Present? Yes No ./ Remarks: HYDROLOGY Wetland Hydrology Indicators: Primai:y Indicators (minimum of one reguired· check all that a1212!y} Secondary Indicators (2 or more reguired} Surface Water (A1) _ Water-Stained Leaves (B9) (except MLRA _ Water-Stained Leaves (B9) (MLRA 1, 2, _ High Water Table (A2) 1, 2, 4A, and 46) 4A, and 4B) Saturation (A3} Salt Crust (B11) _ Drainage Patterns (B10) _ Water Marks (B 1) Aquatic Invertebrates (B13) _ Dry-Season Water Table (C2) _ Sediment Deposits (B2) Hydrogen Sulfide Odor (C1) _ Saturation Visible on Aerial Imagery (C9) Drift Deposits (83) Oxidized Rhizospheres along Living Roots (C3) _ Geomorphic Position (D2) Algal Mat or Crust (B4) Presence of Reduced Iron (C4) _ Shallow Aquitard (03) Iron Deposits (85) Recent Iron Reduction in Tilled Soils (C6) FAC-Neutral Test (05) Surface Soil Cracks (86) Stunted or Stressed Plants (01) {LRR A) Raised Ant Mounds (D6) (LRR A) _ Inundation Visible on Aerial Imagery (87) _ Other (Explain in Remarks) Frost-Heave Hummocks (07) _ Sparsely Vegetated Concave Surface (68) Field Observations: Surface Water Present? Yes ---No -,/ -Depth (inches): Water Table Present? Yes No ,/ Depth (inches): ---- Saturation Present? Yes --No ,/ Depth (inch es): Wetland Hydrology Present? Yes No ,/ -------- {includes capillary frinqe) Describe Recorded Data (stream gauge. monitoring well, aerial photos, previous inspections), if available Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast-Version 2.0 WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region ProJectlSite· RAD Holdings. LLC Appl1cant/Owner· RAD Holdings, LLC City/County: King County/ Renton Sampling Date 07.25.13 State. _W_A ___ Sampling Point. _D_P_4 ____ _ lnvestigator(s): Louis Emenhiser Section, Township. Range: S30. T23N, RSE, W.M. Landform (hillslope, terrace, etc.): _H_i_lls_lo~p_e __________ Local relief (concave, convex, none): _c_o_n_v_ex ______ Slope(%) ~ Subregion (LRR): _L_R_R_-_A _____________ Lat. 47.4520 Long: -122.2094 Datum:----- Soil Map Unit Name: Alderwood gravelly sandy loam. 6 to 15 percent slopes NWI classification: _________ _ Are climatic I hydrologic conditions on the site typical for this time of year? Yes __ ./___ __ No (If no. explain in Remarks.) Are Vegetation _____ , Soil ___ , or Hydrology_ _ significantly disturbed? Are Vegetation __ , Soil _ _, or Hydrology ___ naturally problematic? Are ''Normal Circumstances·· present? Yes_./ _ No (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc . Hydrophytic Vegetation Present? Yes --No -./ -Is the Sampled Area Hydric Soil Present? Yes -./ -No --./ within a Wetland? Yes No Wetland Hydrology Present? Yes No ./ -------- Remarks: Non-wetland in maintained lawn. VEGETATION -Use scientific names of plants. Absolute Dominant Indicator Dominance Test worksheet: Tree Stratum (Plot size 30 meters ) % Cover S12ecies? Status Fraxinus latifolia 20 y FacW Number of Dominant Species 2 1. That Are OBL, FACW, or FAG· (A) 2. Total Number of Dominant 3. Species Across All Strata 4 (8) 4. 20 Percent of Dominant Species 50 = Total Cover That Are OBL, FACW, or FAG (NB) SaQling/Shrub Stratum (Plot size: 10 meters I 1. Prevalence Index worksheet: 2. Total % Cover of: Multi12!y_ by_: 3 OBL species 0 X 1 = 0 4. FACW species 20 x2= 40 5. FAC species 50 x3= 150 -Total Cover FACU species 50 x4= 200 Herb Stratum (Plot size: 1 meter ) UPL species 0 x5= 0 1 Schedonorus arundinaceus 20 y Fae Column Totals: 120 (A) 390 (8) 2 Elymus glaucus 20 y FacU 3. Hypochaeris radicata 20 y FacU Prevalence Index = 8/A = 3.25 4 Agrostis tenuis 10 N Fae Hydrophytic Vegetation Indicators: 5. Holcus Janatus 10 N Fae -Dominance Test is >50% 6 Ranunculus repens 10 N Fae Prevalence Index is :S3.0 1 7 Trifolium pratense 10 N FacU Morphological Adaptations1 (Provide supporting 8. data in Remarks or on a separate sheet) Wetland Non-Vascular Plants 1 9 Problematic Hydrophytic Vegetation 1 (Explain) 10 11 11ndicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 100 -Total Cover Woody_ Vine Stratum (Plot size· ) 1. Hydrophytic 2. Vegetation I Present? Yes No ------= Total Cover % Bare Ground in Herb Stratum 5 Remarks US Army Corps of Engineers Western Mountains, Valleys, and Coast -Version 2.0 SOIL Sampling Point: _D_P_4 __ _ Profile Description: (Describe to the depth needed to docurTlent-ff1e in&cator or confirm the absence of indicators.) Depth Matrix Redox Features (inche~ Color (moist} ______%__ Colar (mrnst) ___JQ_~ Lacz Texture Remarks 0-18 10YR 3/2 95 10YR 4/3 5 C M silt loam --------- --------- --------- --------- --------- --------- --------- --------- 1Tvne· c-concentrat1on, o-oeolet1on, RM-Reduced Matrix, CS-Covered or Coated Sand Grains. 2 Location: PL -Pore Linina, M-Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3 : Histosol (A 1) Sandy Redox (S5) _ 2 cm Muck (A10) __ Histic Epipedon (A2) Stripped Matrix (S6) Red Parent Material (TF2) -Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) Other (Explain in Remarks) -Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) --Depleted Below Dark Surface (A 11) Depleted Matrix (F3) Thick Dark Surface (A 12) ,/ Redox Dark Surface (F6) 31ndicators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surface (F7) wetland hydrology must be present. Sandy Gleyed Matrix (S4) Redox Depressions (F8) unless disturbed or problematic Restrictive Layer (if present): Type: Depth (inches) Hydric Soil Present? Yes ,/ No ------ Remarks: HYDROLOGY Wetland Hydrology Indicators: Prima[Y Indicators (minimum of one reguired· check all that aQQl:il Secondaey Indicators (2 or more reguired) Surface Water (A 1) _ Water-Stained Leaves (89) (except MLRA -Water-Stained Leaves (89) (MLRA 1, 2, _ High Water Table (A2) 1, 2, 4A, and 46) 4A, and 48) Saturation (A3) Salt Crust (B11) -Drainage Patterns (810) i _ Water Marks (B 1) Aquatic Invertebrates (813) -Dry-Season Water Table (C2) _ Sedlment Deposits (82) Hydrogen Sulfide Odor (C1) -Saturation Visible on Aerial Imagery (C9) Drift Deposits (83) Oxidized Rhizospheres along Living Roots (C3) -Geomorphic Position (02) A!gal Mat or Crust (84) Presence of Reduced Iron (C4) -Shallow Aquitard (03) Iron Deposits (85) Recent Iron Reduction in Tilled Soils (C6) FAG-Neutral Test (D5) -Surface Soil Cracks (86) Stunted or Stressed Plants (01) (LRR A) Raised Ant Mounds (06) (LRR A) -Inundation Visible on Aerial Imagery (87) _ Other (Explain in Remarks) Frost-Heave Hummocks (D7) -Sparsely Vegetated Concave Surface (88) Field Observations: Surface Water Present? Yes --No - ,/ -Depth (inches): Water Table Present? Yes --No ,/ Depth (inches) Saturation Present? Yes No ,/ Depth (inches): Wetland Hydrology Present? Yes No ,/ ---------- (includes caoillarv frinael Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections). if available Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast -Version 2.0 WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region Project/Site: RAD Holdings, LLC ApplicanUOwner: RAD Holdings, LLC lnvestigator(s): _Louis Emenhiser City/County: King County/ Renton Sampling Date 07 -25 -13 -----------------State: WA Sampling Point: _D_P_5 ____ _ Section. Township, Range· S3,_0:.:,_T_::2cc3_N:__, _Rcc5_E:__, W_.M_. ----------- Landform (hillslope. terrace, etc.)· _H_il_ls_lo~p_e __________ Local relief (concave, convex none): Convex _____ Slope(%) ~ Subregion (LRR): _L_R_R_-_A _____________ Lat: 47.4519 Long: -122.2097 Datum ----- Soil Map Unit Name-Alderwood gravelly sandy loam, 6 to 15 percent slopes NWI classification: _________ _ Are cl1mat1c / hydro logic conditions on the site typical for this time of year? Yes __ ./ __ No (lfno, explain in Remarks.) Are Vegetation___ _, S01I _ _, or Hydrology_ _ significantly disturbed? Are Vegetation __ , Soil _ . _, or Hydrology ___ naturally problematic? Are ''Normal Circumstances" present? Yes_ ./ _ No (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc . Hydrophytic Vegetation Present? Yes --No -./ -Is the Sampled Area Hydric Soil Present? Yes -./ -No --./ within a Wetland? Yes No Wetland Hydrology Present? Yes No ./ --- ------ Remarks Non-wetland in maintained lawn / blackberry patch. VEGETATION -Use scientific names of plants. Absolute Dominant Indicator Dominance Test worksheet: Tree Stratum (Plot size: 30 meters I % Cover Species? Status Number of Dominant Species 1 Fraxinus latifolia 10 y FacW That Are OBL, FACW, or FAC: 2 (Al 2. Total Number of Dominant 3 Species Across All Strata· 6 (Bl 4. 10 = Total Cover Percent of Dominant Species 33 That Are OBL FACW, or FAC: (A/Bl Sapling/Shrub Stratum (Plot size: 10 meters I 1 Rubus armeniacus 50 y FacU Prevalence Index worksheet: 2. Total % Cover of: Multipty by· 3. OBL species 0 X 1 = 0 4 FACW species 10 x2= 20 5. FAC species 60 x3= 180 50 -Total Cover FACU species 85 x4= 340 Herb Stratum (Plot size: 1 meter I UPL species 0 X 5 = 0 1 Holcus lanatus 20 y Fae Column Totals 155 (Al 540 (B) 2. Elymus glaucus 10 y FacU 3. Hypochaeris radicata 10 y FacU Prevalence Index = BIA -3.48 4. Dactylis glomerata 10 y FacU Hydrophytic Vegetation Indicators: 5 Schedonorus arundinaceus 10 N Fae -Dominance Test is >50% 6. Ranunculus repens 10 N Fae Prevalence Index 1s ::;;3_0 1 7. Agrostis tenuis 10 N Fae Morphological Adaptations 1 (Provide supporting 8 Conium maculatum 5 N Fae data in Remarks or on a separate sheet) Cirsium vulgare 5 N FacU -Wetland Non-Vascular Plants 1 9. 10. Problematic Hydrophytic Vegetation1 (Explain) 11. Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic 90 -Total Cover Wood:t Vine Stratum (Plot size: I 1. Hydrophytic 2. Vegetation ,/ Present? Yes No ------= Total Cover % Bare Ground in Herb Stratum 0 Remarks US Army Corps of Engineers Western Mountains, Valleys. and Coast -Version 2.0 SOIL Sampling Point" --~-P_5 __ _ -------- Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color {mo1st'1 ______Th_______ Color (moist) _____:'&_ ~ Loc2 Texture Remarks 0-18 10YR 3/2 95 10YR 4/3 5 C M silt loam ------·------- --------- ------------- --------- --------- --------- --------- --------- 1 Tvne: C=Concentration. D=Depletion, RM=Reduced Matrix CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining. M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3 : Histosol (A1) Sandy Redox (S5) _ 2 cm Muck (A10) -Histic Epipedon {A2) Stripped Matrix (S6) _ Red Parent Material (TF2) -Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) Other (Explain in Remarks) -Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) Depleted Below Dark Surface (A 11) Depleted Matrix (F3) Thick Dark Surface (A 12) ./ Redox Dark Surface (F6) 3lndlcators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surface (F7) wetland hydrology must be present. Sandy GI eyed Matrix (S4) Redox Depressions (F8) unless disturbed or problematic. Restrictive Layer (if present): Type Depth (inches): Hydric Soil Present? Yes ./ No Remarks: HYDROLOGY Wetland Hydrology Indicators: Prima[Y Indicators {minimum of one reguired· check all that a~12I!;:) Seconda!Y Indicators (2 or more reguired} -Surface Water (A1) _ Water-Stained Leaves (B9) (except MLRA _ Water-Stained Leaves (B9) (MLRA 1, 2, ____ High Water Table (A2) 1, 2, 4A, and 48) 4A, and 48) Saturation (A3) Salt Crust (B11) _ Drainage Patterns (B10) _ Water Marks (B 1) Aquatic Invertebrates (B 13) _ Dry-Season Water Table (C2) _ Sediment Deposits (B2) Hydrogen Sulfide Odor (C1) _ Saturation Visible on Aerial Imagery (C9) Drift Deposits (B3) Oxidized Rhizospheres along Living Roots (C3) _ Geomorphic Position (02) Algal Mat or Crust (84) Presence of Reduced Iron (C4) _ Shallow Aquitard (03) Iron Deposits (B5) Recent Iron Reduction in Tilled Soils (C6) FAG-Neutral Test (05) Surface Soil Cracks (B6) Stunted or Stressed Plants (01) (LRR A) Raised Ant Mounds (06) (LRR A) -Inundation Visible on Aerial Imagery (B7) _ Other (Explain in Remarks) Frost-Heave Hummocks (07) -Sparsely Vegetated Concave Surface (B8) Field Observations: Surface Water Present? Yes --No -./ -Depth (inches) Water Table Present? Yes No ./ Depth (inches): ---- Saturation Present? Yes No ./ Depth (inches)· Wetland Hydrology Present? Yes No ./ ---------- (includes caoillarv frinae) Describe Recorded Data (stream gauge. monitoring well, aerial photos, previous inspections). if available: Remarks· US Army Corps of Engineers Western Mountains, Valleys, and Coast-Version 2 0 WETLAND DETERMINATION DATA FORM -Western Mountains, Valleys, and Coast Region ProJecl/Site RAO Holdings, LLC ApplicanUOwner: RAD Holdings, LLC lnvestigator(s): Louis Emenhiser Landform (hillslope, terrace, etc.): _H_i_lls_la~p_e _________ _ City/County: King County J Renton Sampling Date: 07.25.13 State: _W_A ___ Sampling Point _D_P_6 ____ _ Section, Township, Range· S30, T_2_3_N_. _R_5_E_. W_M ___________ _ Local relief {concave, convex. none): Convex Slope(%):~ Subregion (LRR): _L_R_R_-_A _____________ Lat: 47.4519 Long: _-_12_2_._21_0_0 _______ Datum: ____ _ Soil Map Unit Name: Alderwood gravelly sandy loam, 6 to 15 percent slopes NWI classification Are climatic/ hydro logic conditions on the site typical for this time of year? Yes __ ,/ _ No _ (If no, explain in Remarks.) Are Vegetation ____ , Soil ___ , or Hydrology_ _ significantly disturbed? Are Vegetation __ , Soil_ _, or Hydrology ___ naturally problematic? Are ·'Normal Circumstances·· present? Yes_ ./ _ No (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes --Na -,/ -Is the Sampled Area Hydric Soil Present? Yes No ,/ ,/ ----within a Wetland? Yes Na Wetland Hydrology Present? Yes Na ,/ ------ Remarks Non-wetland in blackberry patch. VEGETATION -Use scientific names of plants. Absolute Dominant Indicator Dominance Test worksheet: Tree Stratum (Plot size· 30 meters I % Cover Sgecies? Status Acre macrophyllum 30 y FacU Number of Dominant Species 1 1. That Are OBL, FACW, or FAC: (A) 2 Total Number of Dominant 3 Species Across All Strata: 4 (B) 4 30 Percent of Dominant Species 25 = Total Cover That Are OBL, FACW, or FAC: (A/B) Saglrng/Shrub Stratum (Plot size: 10 meters ) 1. Rubus armeniacus 70 y FacU Prevalence Index worksheet: 2 Symphoricarpos albus 10 N FacU Tota I % Cover of. Multigly: by:: 3. OBL species 0 X 1 = 0 4 FACW species 0 x2= 0 5 FAC species 20 x3= 60 80 = Total Cover FACU species 130 x4= 520 Herb Stratum (Plot size: 1 meter I UPL species 0 x5= 0 1. Elymus glaucus 20 y FacU 150 580 Column Totals: (A) (B) 2. Ranunculus repens 20 y Fae 3. Prevalence Index = B/A = 3.86 4. Hydrophytic Vegetation Indicators: 5. -Dominance Test is ::>50% 6. Prevalence Index is :s3.0 1 7. Morphological Adaptations 1 (Provide supporting 8. data in Remarks or on a separate sheet) Wet!and Non-Vascular Plants 1 -9. 10. Problematic Hydrophytic Vegetation1 (Explain) 11 1lndicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 40 -Total Cover Wood'i.. Vine Stratum (Plot size: I 1. Hydrophytic 2. Vegetation ./ Present? Yes Na ------= Total Cover % Bare Ground in Herb Stratum 0 Remarks: US Army Corps of Engineers Western Mountains. Valleys, and Coast-Version 2.0 SOIL Sampling Point: _D_P_6 __ _ Profile Description: (Describe to the-deJ)ih needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) ~ Color (moist) ' -Texture Remarks ______%__ ~ ___lQ_C__ 0-18 10YR 3/2 100 silt loam ------------ ------------ ------------ --------- ------------ ------------ --------- --------- 1Tvne: c-concentration, o-oeoletion, RM-Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Linina, M=Matrix Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3 : _ Histosol (A 1) Sandy Redox (S5) _ 2 cm Muck (A10) _ Histic Epipedon (A2) Stripped Matrix (S6) _ Red Parent Material (TF2) _ Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) other (Explain in Remarks) Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) Depleted Below Dark Surface (A11) Depleted Matrix (F3) Thick Dark Surface {A 12) Redox Dark Surface (F6) 3 lndicators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surface (Fl) wetland hydrology must be present, Sandy Gleyed Matrix (S4) Redox Depressions (FB) unless disturbed or problematic Restrictive Layer {if present): Type Depth (inches) Hydric Soil Present? Yes ./ No Remarks HYDROLOGY Wetland Hydrology Indicators: Primaey Indicators (minimum of one reguired· check all that a~~ltl Secondact Indicators (2 or more reguired) Surface Water (A 1) _ Water-Stained Leaves (89) {except MLRA _ Water-Stained Leaves (B9) (MLRA 1, 2, _ High Water Table (A2) 1, 2, 4A, and 48) 4A, and 48) Saturation (A3) Salt Crust (811) _ Drainage Patterns (810) _ Water Marks (B1) Aquatic Invertebrates (B 13) _ Dry-Season Water Table (C2) _ Sediment Deposits (82) Hydrogen Sulfide Odor (C 1) _ Saturation Visible on Aerial Imagery (C9) Drift Deposits (83) Oxidized Rhizospheres along Living Roots (C3) -Geomorphic Position (D2) Algal Mat or Crust (84) Presence of Reduced Iron (C4) -Shallow Aquitard (03) Iron Deposits (85) Recent Iron Reduction in Tilled Soils (C6) FAG-Neutral Test (D5) Surface Soil Cracks (86) Stunted or Stressed Plants (01) (LRR A) Raised Ant Mounds (D6) (LRR A) _ Inundation Visible on Aerial Imagery (B7) _ Other (Explain in Remarks) Frost-Heave Hummocks (D7) _ Sparsely Vegetated Concave Surface (88) Field Observations: Surface Water Present? Yes --No -,( -Depth (inches). Water Table Present? Yes No ,( Depth (inches): ---- Saturation Present? Yes No ,( Depth (inches)· Wetland Hydrology Present? Yes No ,( ----------(includes capillary frinqe) Describe Recorded Data (stream gauge, monitoring well, aerial photos. previous inspections), if available· Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast-Version 2.0 ------------ 0 >< .z "T1 ~m " z "'0 {! m " -~ --, ~ ~ (D 0 C. ~ O" " '< = ;o !s (D 0 => --CT 0 (D => ~ ..... = ~~II 0 ..... 0 "' 0 0 q !Acre Job: 13039 Drawn By: L Emenhiser Date: 09.04.2013 Revision #: NIA • • C ' ' z G) ""Cl )> (I) G) z 0 )> ;; ""Cl 0 z --1 ~ a, --1 0 ;; r ~ Ill C "T1 "T1 m ;o -z PREPARED FOR: ~ m -I s;; z 0 RAD HOLDINGS, LLC ATTN. RORY DEES 6252167TH AVE, SE BELLEVUE, WA 98006 m G) >< O;o(f) ::u )> --1 -<-<mZ m r G) --.. j \_ __ _ ~.LO'if\'11 .L -~~'ell. ,, 'V q~'i ii,; ,, '" '' ,,1 ,,, 0 ?~ .1'/ ·,I,~ 1a /,o\ ~ _,, '" 08 ,r,• 0 ._f'' ,,, 0 ~"· '~ 0 ~ • 0 ,icO @ 0 0 ,1 0 ."' 0 0 "' ~*'' ~~, ----- m >< (I) (/) --1 ,iZ ;o G) ----1 G) m )> >< ::u (/) )> -I G) -mZ G) -,~, ,,, """·11 .... ,,,_ Tl ---- Cb; r;g. 0 'ti. 0 O ''il O 0 ,0 O O ,' '€') 0 % O O O 00"'9· 0 ,t,' • G£l cp' 0 co<>' 0 <ii) ' ' '(:) ,;' ,, ef"' 0 0 - cf',., Qi 0 .... 6'(' "''' () C'J) .~a. o v')~-- ------ "' (I) m "T1 >< ;o (/) -I z G) ,& ' ' ~----' Ir • l.''I - If I~, I' Ir --L-.--,i--, 1l ' ' I ------~ 1, f I I f If I I 'f 1· (jJ 0~ q )> m Ill --1 --1 cm, "Tl G) )> -nOZ m ;o o ;o -< )> ~ ;,l ,1 If 1f 1, CRITICAL AREAS MAP If 1f if If RAD HOLDINGS, LLC -3112 TALBOT ROAD RENTON, WA TAX PARCEL NO. 302305-9028 -"0 ts., C -, o< S:: m "U ::u -I PREPARED BY: Acre Environmental Consulting, LLC 17715 28th Avenue NE Lake Forest Park, WA 98155 Phone: (206) 450-7746 Email: louis@acreenvironmental.com <1~~" ~ ~~1;!4 IRolv.1;t[~~G, 'V'r"'li: e,O',:',i MAP SHEET: CA1.00