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RS_Drainage_TIR_20170421_v1
Job No. 15-098 Via 405 Apartments PRELIMINARY TECHNICAL INFORMATION REPORT Renton, Washington Issued: March 21, 2017 Prepared For: RVA Cinema, LLC 14410 Bel-Red Road Bellevue, WA 98007 Prepared By: Beau J. Willert, EIT Travis J. Wageman, EIT Reviewed By: Richard A. Tomkins, PE Job No. RVAC0000-0002 Page 1-1 March 21, 2017 TABLE OF CONTENTS 1 EXECUTIVE SUMMARY........................................................................................................................... 1-3 2 CONDITIONS AND REQUIREMENTS SUMMARY ..................................................................................... 2-1 2.1 CORE REQUIREMENTS ..................................................................................................................... 2-1 2.2 SPECIAL REQUIREMENTS ................................................................................................................. 2-3 3 OFFSITE ANALYSIS ................................................................................................................................. 3-1 3.1 RESOURCE REVIEW .......................................................................................................................... 3-1 3.2 UPSTREAM BASIN ............................................................................................................................ 3-3 3.3 DOWNSTREAM DRAINAGE ROUTE .................................................................................................. 3-3 3.4 PROPOSED MITIGATION MEASURES ............................................................................................... 3-6 4 FLOW CONTROL AND WATER QUALITY DESIGN .................................................................................... 4-1 4.1 PERFORMANCE STANDARDS ........................................................................................................... 4-1 4.2 EXISTING CONDITIONS..................................................................................................................... 4-3 4.3 DEVELOPED CONDITIONS ................................................................................................................ 4-5 4.4 DETENTION FACILITY ANALYSIS ....................................................................................................... 4-5 4.5 FLOW SPLITTER DESIGN ................................................................................................................... 4-6 4.6 WATER QUALITY FACILITY ANALYSIS ................................................................................................ 4-6 5 CONVEYANCE SYSTEM ANALYSIS & DESIGN .......................................................................................... 5-1 6 SPECIAL REPORTS AND STUDIES ............................................................................................................ 6-1 6.1 FLOOD HAZARD DATA ...................................................................................................................... 6-1 6.2 GEOTECH REPORT ............................................................................................................................ 6-1 6.3 STREAM STUDY ................................................................................................................................ 6-1 7 OTHER PERMITS .................................................................................................................................... 7-1 8 CONSTRUCTION STORMWATER POLLUTION PREVENTION .................................................................... 8-1 9 BOND QUANTITIES, FACILITY SUMMARIES AND DECLARATION OF COVENANT ..................................... 9-1 10 OPERATIONS AND MAINTENANCE ...................................................................................................... 10-1 Job No. RVAC0000-0002 Page 1-2 March 21, 2017 LIST OF SUPPLEMENTAL INFORMATION SECTION 1 TIR Worksheet SECTION 3 Offsite Drainage Exhibit Triad Topo Survey FEMA Flood Insurance Rate Map USDA Soils Map King County Area, Washington Soil Survey City of Renton Hazard Maps Drainage Complaints Map City of Renton Drainage Complaints Email Correspondence Upstream Basin Exhibit Black River Drainage Basin Exhibit SECTION 4 Existing Conditions Exhibit Developed Conditions Exhibit Total Threshold Discharge Area Exhibit Flow Control – ExistPeak City of Renton Flood Hazard Modular Wetland Exhibit WWHM Basin Calculations SECTION 6 Flood Hazard Data Exhibit Geotech Report Stream Study Job No. RVAC0000-0002 Page 1-3 March 21, 2017 1 EXECUTIVE SUMMARY The Via 405 Apartments project proposes to develop a 270-unit apartment building within the City of Renton. The property is located at 25 South Grady Way, Renton, WA 98055 (tax parcel #723200-0010). The site is zoned CO (Commercial Office) with a total parcel area of 2.6± acres. The project boundary area of 2.41 acres is composed of 2.03 acres on-site and 0.38 acres off-site. The remaining parcel area not proposed within the project boundary (2.6 ac - 2.03 ac = 0.57 ac) contains sensitive areas that will remain undisturbed. See the Existing Conditions Exhibit and Developed Conditions Exhibits located at the end of Section 4 for reference. The site is located in a portion of the Northeast ¼ of Section 19, Township 23 North, Range 5 East, W.M., King County, Washington just to the northeast of the I-405/SR-167 Interchange. See below for a vicinity map. Job No. RVAC0000-0002 Page 1-4 March 21, 2017 The project is required to comply with Core Requirements #1-9 and applicable special requirements of the 2017 City of Renton Surface Water Design Manual (2017 COR SWDM). See Section 2 – Conditions and Requirements Summary of this report for an outline of these requirements and how they have been addressed for this project. In the existing condition, the site contains a movie theater, with associated parking and drive aisles. Rolling Hills Creek, a non-fish bearing stream, runs through the southern portion of the site from east to west. To the north and east, the site is made up of parking lots and sidewalks. The Evergreen office building lies to the west, and I-405 to the south. Topography on the site is variable and ranges from a low point at 20 feet to a high point of about 30 feet. The northern portion of the site slopes gradually to the north with grades of 1-5% while the southern half gradually slopes south until the steeper banks of the Rolling Hills Creek that range from 25-50%. The existing project site consists of a single Threshold Discharge Area (TDA), since all surface water runoff and on-site storm drainage systems combine within one-quarter mile downstream. Under existing conditions, on-site runoff sheet flows either north or south and is collected via on-site catch basins. The TDA consists of a large portion of the existing commercial development north of the project site up to and including a portion of S Grady Way. The upstream portion of the TDA, or Upstream Drainage Basin (UDB), is collected by an existing storm drain system that connects to the on-site system near the northeast corner of the site. TAD runoff is then conveyed to an oil/water separator vault located on the east side of the existing theater. The runoff is then discharged into Rolling Hills Creek near the southeast corner of the site. For more information see Section 4 of this report. All site improvements will be contained within a disturbance envelope (project boundary) that occupies the northern three-fourths of the site. The remaining southern portion of the site (containing Rolling Hills Creek and its functional buffer) will remain undisturbed. The proposed site plan supports a single-building apartment complex with 270 units and ground level parking. Job No. RVAC0000-0002 Page 1-5 March 21, 2017 Under developed conditions, TDA and drainage patterns will be maintained. In compliance with the requirements of the 2017 COR SWDM, Enhanced Basic water quality treatment will be provided for all disturbed or created pavement areas using a biofiltration vault. This project qualifies for an exemption from the flow control standard. Accordingly, a stormwater detention facility is not required or proposed. See Section 4 of this report for more details and analysis of the proposed stormwater management facilities. RVA Cinema, LLC TBD TBD Richard A. Tomkins, PE Triad Associates (425) 415-2000 Via 405 Apartments 23N 5E 19 25 S Grady Way Renton, WA 98055 TBD N/A TBD TBD Black River Drainage Basin Enhanced Basic Water Quality Contains 15%-25% UL 15%-25% 2 TBD 27.6 NAVD 88 Multi-Family (Project), Retail/Office (Surrounds) Existing oil/water separator will remain Modular Wetland Modular Wetland Oil/Water Separator (Existing) Project qualifies for flow control facility exception Job No. RVAC0000-0002 Page 2-1 March 21, 2017 2 CONDITIONS AND REQUIREMENTS SUMMARY As discussed in the Executive Summary, the project is required to comply with Core Requirements #1-9 and the applicable Special Requirements of the 2017 COR SWDM. See below for an outline of these requirements and how they have been addressed for this project. 2.1 CORE REQUIREMENTS 2.1.1 Core Requirement #1: Discharge at the Natural Location Runoff for the site and the UDB in the developed condition will maintain the natural discharge location. Please refer to Section 3 - Offsite Analysis for a description of the existing drainage conditions of the site. 2.1.2 Core Requirement #2: Offsite Analysis See Section 3 - Offsite Analysis 2.1.3 Core Requirement #3: Flow Control This project is not required to provide flow control per the 2017 COR SWDM. See Section 4 for more information. 2.1.4 Core Requirement #4: Conveyance System The proposed stormwater conveyance system for the project site will be designed to meet the requirements and design standards of the 2017 COR SWDM. The conveyance system details will be addressed at the final engineering stage. Job No. RVAC0000-0002 Page 2-2 March 21, 2017 2.1.5 Core Requirement #5: Erosion and Sediment Control To be addressed at the final engineering stage. 2.1.6 Core Requirement #6: Maintenance and Operations To be addressed at the final engineering stage. 2.1.7 Core Requirement #7: Financial Guarantees and Liability To be addressed at the final engineering stage. 2.1.8 Core Requirement #8: Water Quality This project is required to comply with the Enhanced Basic Water Quality treatment standard per the 2017 COR SWDM. A Modular Wetland Biofiltration Vault is proposed to achieve this treatment standard. See Section 4 – Flow Control and Water Quality Design for more information. 2.1.9 Core Requirement #9: On-Site BMPs Do to the size of the proposed project area (2.41 acres); the project is required to comply with the Large Lot On-Site BMP requirements per the 2017 COR SWDM. Application of on-site BMPs must be done to the maximum extent feasible specific to the project location, size and impervious coverage. Based on our specific site, full dispersion of runoff is infeasible due to the lack of a sufficient native vegetated flow path of at least 100 feet. Full infiltration of roof runoff is impractical. The soil characteristics within the project boundary do not have the proper infiltration capabilities to reliably provide full infiltration. The project will provide a minimum top soil quality and depth through soil amendment to all pervious surfaces. A Post-Construction Soil Management Plan will be prepared based on the requirements of the 2017 COR SWDM at the final Job No. RVAC0000-0002 Page 2-3 March 21, 2017 engineering phase of the project. In addition, a portion of the roof area for the proposed 270-unit apartment building will be landscaped as “green” roof. Together with soil amendment, the “green” roof area will help reduce runoff peaks and volumes by providing increased water storage and additional opportunity for evapotranspiration. 2.2 SPECIAL REQUIREMENTS 2.2.1 Special Requirement #1: Other Adopted Area-Specific Requirements 2.2.1.1 Master Drainage Plans (MDPs) Not applicable. 2.2.1.2 Basin Plans (BPs) According to the City of Renton Drainage Basins Map, the site is located within the Black River Drainage Basin, a sub-basin of the Duwamish-Green River Watershed. A map of the drainage basin can been see at the end of Section 3. 2.2.1.3 Salmon Conservation Plans (SCPs) Not applicable. 2.2.1.4 Lake Management Plans Not applicable. 2.2.1.5 Hazard Mitigation Plan Not applicable. 2.2.1.6 Shared Facility Drainage Plans (SFDPs) Not applicable. Job No. RVAC0000-0002 Page 2-4 March 21, 2017 2.2.2 Special Requirement #2: Flood Hazard Area Delineation The 100-year floodplain is delineated on the site improvement plans and flood storage impacts noted (project will result in no loss of flood storage) on Sheet C2. 2.2.3 Special Requirement #3: Flood Protection Facilities Not applicable. 2.2.4 Special Requirement #4: Source Controls This project is classified as a commercial development in accordance with the King County Stormwater Pollution Prevention Manual and Renton Municipal Code, Title IV. Appropriate stormwater BMPs will be utilized in an effort to control pollution, including Required Best Management Practices for all Properties with Commercial Activities (A-1), Pressure Washing of Buildings, Rooftops, and Other Large Objects (A-15), and Sidewalk Maintenance (A-32). 2.2.5 Special Requirement #5: Oil Control Special oil control BMPs are not required for this project since the amount of traffic trips generated is under the threshold designation for a “high-use” site (ADT greater than 100 vehicles per 1,000 square feet of gross building area). However, a large oil/water separator currently treats runoff from portions of the project site and all of the UDB, prior to discharge to Rolling Hills Creek. This facility will be relocated (outside of the proposed building footprint) and will continue to provide oil control for the basin. 2.2.6 Special Requirement #6: Aquifer Protection Area Not applicable. See Section 3.1.3 – Sensitive Areas for more details. Job No. RVAC0000-0002 Page 3-1 March 21, 2017 3 OFFSITE ANALYSIS Triad performed a field visit on February 14, 2017 to identify any potential problems upstream or downstream of the project site. The weather was overcast and approximately 45 degrees at the time of the field visit. See the Offsite Drainage Exhibit located at the end of this section to aid in this discussion. There is only a single downstream analysis area or Threshold Discharge Area (TDA) for the project. The downstream analysis area is within the Black River Drainage Basin a sub-basin of the Duwamish-Green River Watershed; see the Black River Drainage Basin Map at the end of this section for more information. The downstream analysis area for the project site begins where the drainage leaves the on-site stormwater conveyance system and discharges into the Rolling Hills Creek. In the existing condition, there are three discharge points on-site. The three stormwater discharge points will be maintained in the developed condition. The discharge locations can be seen on the topo survey performed by Tirad at the end of this section. From the three on-site discharge locations, once stormwater enters Rolling Hills Creek, stormwater is discharged via either a 12’ diameter CMP culvert at elevation 17.28 or a 48” diameter concrete pipe at elevation 18.13. Both structures convey drainage under the I-405/SR-167 interchange. The 48” concrete pipe conveys drainage to the southwest to a stormwater pond that eventually discharges to Rolling Hills Creek to the southeast. The 12’ culvert conveys drainage directly to Rolling Hills Creek to the south, more than a quarter mile downstream. 3.1 RESOURCE REVIEW Available existing resources were researched for the site and relevant information has been summarized below. Job No. RVAC0000-0002 Page 3-2 March 21, 2017 3.1.1 FEMA Maps The project site is mapped on Panel 977 of 1725, Map No. 53033C0977_F, and Panel 979 of 1725, Map No. 53033C0979_F, of the FEMA King County Flood Insurance Rate Map dated May 16, 1995. Portions of the site lies within mapped flood boundaries. A copy of the FEMA Maps have been included at the end of this section. See also Flood Hazard Data Exhibit included in Section 6. 3.1.2 Soil Survey (USDA/ Natural Resources Conservation Service) A soils survey for the project site was obtained through The United Stated Department of Agriculture/Natural Resources Conservation Service Soil Survey database. The USDA Soil Survey indicates that the site soil is Urban Land (Ur). The King County Area, Washington Soil Survey description guide states that Ur as having properties too variable to rate. A copy of the applicable portion of the King County Area, Washington Soil Survey has been included at the end of this section. A site specific soils report has been prepared by Golder Associates, a copy of which is included in Section 6. 3.1.3 Sensitive Areas The site location has been identified on copies of the following City of Renton Hazard Maps: Coal Mine - Site not mapped as lying within a hazard area. Erosion - Site not mapped as lying within a hazard area. Flooding - Site mapped as lying within a hazard area. Refer to Section 6 – Special Reports and Studies for more information. Liquefaction - Site mapped as lying within a hazard area. Seismic - Site mapped as lying within a hazard area. Landslide - Site not mapped as lying within a hazard area. Aquifer Protection - Site not mapped as lying within hazard area. Steep Slope - Site mapped as containing 15% - 25% slopes (actually contains slopes in excess of 40%). Job No. RVAC0000-0002 Page 3-3 March 21, 2017 (See the end of this section for appropriate maps.) 3.1.4 King County Drainage Complaints The King County iMap was used to look up drainage complaints from the on-site TDA discharge point to ¼-mile downstream. No complaints are recorded for this reach. 3.2 UPSTREAM BASIN A large 16.46-acre Upstream Drainage Basin extends north of the site to S Grady Way and includes a portion of both properties to the east and west. The 16.46 acres includes large amounts of parking lot, roadway, and roof area. For more details, see the Upstream Basin Exhibit located at the end of this section. 3.3 DOWNSTREAM DRAINAGE ROUTE The existing project site consists of a single Threshold Discharge Area (TDA), in which the surface water and on-site storm drain system combine within one-quarter mile downstream. As previously mentioned, the site is tributary to Rolling Hills Creek, located within the Black River Drainage Basin, a sub-basin of the Duwamish-Green River Watershed. The drainage components of the existing downstream flow paths are described below. For a visual of each of the components within the downstream drainage route, please refer to the exhibit entitled Offsite Drainage Exhibit at the end of this section. Component 1 ~ Rolling Hills Creek (0' – 110’) The runoff from the Project Boundary Basin discharges into Rolling Hills Creek (shown below). Rolling Hills Creek flows to the west along the north side of I-405 and has an approximate slope of 0.35%. From the DEA Stream Study (included in Section 6) the on-site portion of the creek is described as follows, “the creek has a channel width from 7 to 9 feet and a bank full width of 12 to 13 feet wide. The bank full width was delineated and surveyed in the field. The Job No. RVAC0000-0002 Page 3-4 March 21, 2017 stream bank is eroded with vertical to overhanging slopes 2 feet high. The streambed through the study area is primarily gravel, sand, and fines with some cobble and areas of rip rap. There is little woody debris in the stream. There is trash and abandoned house hold items in both the stream and buffer areas.” From the southwest corner of the site, the creek conveys the site runoff for approximately 110-feet to the west until it reaches a culvert and a concrete pipe, both of which cross under the I-405/SR-167 interchange. No evidence of active erosive scour or overbank was observed for this drainage component. Component 2A ~ 12-foot CMP Culvert (110’ – 1,058) Runoff from Component ‘1’ is collected by a 12-foot corrugated metal culvert that conveys the runoff southwest, under the I-405/SR-167 interchange. The approximate 948- feet of culvert discharges into Rolling Hills Creek that runs along the Job No. RVAC0000-0002 Page 3-5 March 21, 2017 southeast side of the I-405/SR-167 interchange. An accumulation of debris partially obstructs the inlet to the culvert, likely reducing its full flowing capacity. The area surrounding the inlet shows no signs of erosion or flooding caused by the upstream conveyance system. Component 2B ~ 48-inch Concrete Pipe System (110’-530’) Runoff from Component '1' is collected by a 48-inch concrete pipe that conveys the runoff to the west, under the I-405/SR-167 interchange, for approximately 420-feet. This concrete pipe then enters a manhole and flows south through another pipe (Component 3B). The inlet to the pipe partially obstructed with debris and sediment buildup, decreasing the full capacity of the pipe. However, there were no signs of erosion at the inlet, and no signs of flooding associated with this conveyance element. Component 3B ~ 48-inch Concrete Pipe System (530’-1,435’) Runoff from Component ‘2B’ enters a manhole and flows southwest into a concrete pipe for approximately 905-feet under I-405. This portion of the pipe system was inaccessible and the information regarding the concrete pipe was take from the City of Renton COR Maps. Drainage from the concrete pipe enters another manhole and then flows southeast. Component 4B ~ 48-inch Concrete Pipe System (1,435’ – 1,767’) Runoff from Component ‘3B’ outlets into a manhole and is directed southeast into a concrete pipe for approximately 332-feet. The pipe runs under the I-405/SR-167 interchange and discharges into Rolling Hills Creek on the southeast side of the interchange. This portion of the pipe system was inaccessible and the information regarding the concrete pipe was take from the City of Renton COR Maps. Job No. RVAC0000-0002 Page 3-6 March 21, 2017 3.4 PROPOSED MITIGATION MEASURES At the time of Triad’s field visit, there was no visual evidence of active erosive scour or flooding within the downstream receiving conveyance systems. However, substantial amounts of debris and sediment buildup was observed at the inlets to the 12-foot CMP Culvert and the 48-inch Concrete Pipe. A review of King County's Drainage Complaint record did not reveal any documented complaints for either the on-site or downstream portions of the project. See the Drainage Complaints Map located at the end of this section. Other than the typical recommendation to remove trash, debris, and sediment from the creek channel and culvert inlets, and implementing a program for regular ongoing inspection and maintenance, we see no need for extraordinary off-site mitigation. 2,400400 Offsite Drainage Exhibit This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere Notes 03/13/2017 Legend 272 0 136 272 Feet Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Other City of Renton Parcels 100' Primary 100' Intermediate 20' Primary 20' Intermediate 5' Primary 5' Intermediate 2' Primary 2' Intermediate 1 2A 2B 3B 4B PROJECT SITE ROLLING HILLS CREEK ROLLING HILLS CREEK Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 3/13/2017 Page 1 of 35257510525753052575505257570525759052576105257510525753052575505257570525759052576105257630559120559140559160559180559200559220559240559260559280559300 559120 559140 559160 559180 559200 559220 559240 559260 559280 559300 47° 28' 9'' N 122° 12' 55'' W47° 28' 9'' N122° 12' 46'' W47° 28' 5'' N 122° 12' 55'' W47° 28' 5'' N 122° 12' 46'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 40 80 160 240 Feet 0 10 20 40 60 Meters Map Scale: 1:861 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: King County Area, Washington Survey Area Data: Version 12, Sep 8, 2016 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 31, 2013—Oct 6, 2013 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 3/13/2017 Page 2 of 3 Map Unit Legend King County Area, Washington (WA633) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI Ur Urban land 2.6 100.0% Totals for Area of Interest 2.6 100.0% Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 3/13/2017 Page 3 of 3 k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkD r SW 7th St SE 128th St SE 192nd StLindAveSWMainAveSS 132nd St Factory PlN Talbot Rd SN 3rd St RainierAveS 164thAveSETukwila Pk w y SPuget Dr NE 4th St S 3rd St S 1 2 9 th S t68thAveSSWSunsetBlvd SW 16th St 116thAveSEN 4th St I n t e r u r b a n Av e S WilliamsAveNBronsonW a y N NE7thSt 124thAveSES 7th St SERenton IssaquahRd Rai ni er AveNNewcastle Way CoalCr e e k PkwySESW 41st St T a ylo r P l N WNESunsetBlvdWellsAveNUnionAveNEN E 3 rd S tHa r die A v eSWS180th St Maple Valley Hwy 140thAveSES G ra d yWayS 2 1 s tSt BensonRdSRe nt o n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrR d SE 168th St Beaco n A v e S 68thAveSLoganAveN108thAveSEForestDr SE S2ndSt 141 s tAve S ERainierAveS 156thAveSES E 183rd StBenson Dr SS 124th StS 43rd St Airport Way S W G radyW a y S E J o n e s RdSunsetBlvdN Puget Dr SESE 204th W aySW 34th StMo n s ter RdSW S E 1 4 2 n d P lWestValleyHwySSEMay ValleyRd SunsetBlvdNS C a r r RdHouserWayNNewcastle GolfClubRd S 133rd St WilliamsAveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAveSWestVal leyHwyWestValleyHwyParkAveN108thAveSE6 6 t h Av e SWMercerWayWMercer W ay LakemontBlvdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of RentonSensitive Areas 0 0.5 10.25 Miles Information Technology - GISmapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended forCity display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Coal Mine Hazards Severity HIGH MODERATE UNCLASSIFIED Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN PROJECT SITE k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkD r SW 7th St SE 128th St SE 192nd StLindAveSWMainAveSS 132nd St Factory PlN Talbot Rd SN 3rd St RainierAveS 164thAveSETukwila Pk w y SPuget Dr NE 4th St S 3rd St S 1 2 9 th S t68thAveSSWSunsetBlvd SW 16th St 116thAveSEN 4th St I n t e r u r b a n Av e S WilliamsAveNBronsonW a y N NE7thSt 124thAveSES 7th St SERenton IssaquahRd Rai ni er AveNNewcastle Way CoalCr e e k PkwySESW 41st St T a ylo r P l N WNESunsetBlvdWellsAveNUnionAveNEN E 3 rd S tHa r die A v eSWS180th St Maple Valley Hwy 140thAveSES G ra d yWayS 2 1 s tSt BensonRdSRe nt o n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrR d SE 168th St Beaco n A v e S 68thAveSLoganAveN108thAveSEForestDr SE S2ndSt 141 s tAve S ERainierAveS 156thAveSES E 183rd StBenson Dr SS 124th StS 43rd St Airport Way S W G radyW a y S E J o n e s RdSunsetBlvdN Puget Dr SESE 204th W aySW 34th StMo n s ter RdSW S E 1 4 2 n d P lWestValleyHwySSEMay ValleyRd SunsetBlvdNS C a r r RdHouserWayNNewcastle GolfClubRd S 133rd St WilliamsAveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAveSWestVal leyHwyWestValleyHwyParkAveN108thAveSE6 6 t h Av e SWMercerWayWMercer W ay LakemontBlvdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of RentonSensitive Areas 0 0.5 10.25 Miles Information Technology - GISmapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended forCity display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Erosion Hazard Severity High Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN PROJECT SITE RentonKent Newcastle King CountyTukwilaMercer Island Bellevu e Lake Washington Lake Youngs Panther Lake Lake Boren Cedar RiverBlack River May Creek Springbrook Creek Cougar MountainCougar Mountain Coal Creek ParkCoal Creek Park Cedar River Natural ZoneCedar River Natural Zone May Creek ParkMay Creek Park Soos Creek Park and TrailSoos Creek Park and Trail Black River Riparian ForestBlack River Riparian Forest McGarvey Open SpaceMcGarvey Open Space Maplewood Community ParkMaplewood Community Park ValleyValley BensonBenson HighlandsHighlands West HillWest Hill East PlateauEast Plateau SE 192ND STTALBOT RD S140TH AVE SERAI N I E R A V E S EAST VALLEY RDSE 168TH ST RENTON A V E S116TH AVE SENE 12TH STE M ERCER WAY148TH AVE SENE 7TH S T84TH AVE SHOQUIAM AVE NENEWCASTLE W AY W M E RCER WAY S 128TH ST SW 41ST ST PARK AVE N128TH AVE SESE JONES R D E VALLEY HWYSE 72ND ST SE 164TH ST NILE AVE NEN 10TH S T SE 183RD S TUNION AVE NE156TH AVE SEUNION AVE SENE 2ND ST 148TH AVE SESE 164TH STLIND AVE SWUNION AVE NE116TH AVE SESW 7TH ST N 8TH ST EDMONDS AVE NEPUGET DR S E NE 27TH ST 156TH AVE SERENTON AVE S BENSON RD SMONROE AVE NE116TH AVE SENE 4TH ST SR 515 SUNS E T BLV D N E PARK AVE NM APLE VALLEY HWY SW 43RD ST NE 3RD STLOGAN AVE NSW SU NSET BLVD SW GRADY W A Y N 3RD STRAINIER AVE N140TH WAY S ESR 167108TH AVE SEN 6TH ST S 2ND S T 108TH AVE SESR 515[^405 [^405 Effective FEMA FloodInsurance Rate Map µ Legend Renton City Limits Zone AE, A, AH, AO - Regulatory Zone X - Non Regulatory 0 0.5 10.25 Miles Public Works - Surface Water UtilityPrint Date: 11/05/2012 Data Sources: City of Renton, FEMA FIRM revised May 16, 1995.Cedar River flood hazard area updated with FEMA Cedar RiverLOMR (Case No. 06-10-B569P) approved December 4, 2006. This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended forCity display purposes only. PROJECT SITE ^_ Airport Way S Tobin StSeneca AveNW 2ndStevens Ave NWLind Ave NWMapleTaylor Ave NWHardie Ave NWS 132nd StRentonAve S S 134th St Victoria SW Langston Rd SW 3rd Pl 4th Pl SW 5th Ct SW 7th StStevens AveRai n i er Av e4 th P lS 7th St S 6th St Shattuck AveS3rd Pl Whitworth Ave SMorris Ave SSmithers Ave SS 2nd StLake Ave SLogan Ave SBurnett Ave S900Maple AveHardie Ave SWS 3rd St Burnett Ave SS 5th St H a rdie A v e S WSW 5th PlMinkler Blvd 70th Ave SSW 39th StOakesdale Ave SWSW 27th St SW 34th StWest Valley Hwy148thAve SENE 31st St S E 8 9 th P lSE 95th Way SE 95th Way S E 9 1 s t S E 9 0th133rd 132nd Pl SENewcastle Rd REV136th Ave SEA v e S EAve135th135th 14 4th Pl S E P l SESE136thSEAve14 4th Pl S E Ave SE 85th144th Ave SESE 83rd St SESE th145 S t1 4 6th Pl SEAveSt 84th147th SE148th Ave SE116th Pl S E117th Ave SESE 88th Pl SE 93rd St 122nd Pl SE118th Ave SESE 95th Pl 127th Pl SE132nd Ave SE127th Pl SE127th Ave SE129th Ave SE129th Pl SE W aySE 84thSE 91st St 126th Ave SESE 90th St SE 89th St SE 88th St SE 95th Way S E 9 5 t h W a y SE 89th Pl SE 88th St 128th Ave SEGensing Ave G e n sin g A v e SE 92nd St SE 89th PlLakeMeadow Burnett Ave NPark Ave NN 34th St N 32nd St. N 30th St N 28th StN 28th Pl N 29th St N 30th St N 31st St N 32nd St N 33rd St N 33rd Pl N 34th St N 35th St N 36th St NE 28th St NE 31st StJones AveMonterey Ct NEStNE 36th NE 33rd StBlvd NWashingtonAve NN 37th StN 38th N 40th St 116th Ave SELincoln PlNE 43rd Pl NE 40th St SE 86thMo nt ere y P l N ELincoln AveAve NEJonesN 29th N 30th N 31st N 32nd 33rd SE 72nd St.112 Ave. SELake Wash. Blvd NESE 68th St. SE 80th St. SE 76th St.NE 48th St. NE 44th St.111th Pl. SESE 76th Pl. SE 77th Pl. NE 50th St. SE 80th St SE 182nd SE 184th St149th Ave SE150th Ave SE SE 183rd154th PlDrPetrovitsky Rd SE 184th St SE 182nd Pl 160th AveOld P et R d177th Pl151stSE 176th Pl 152nd Pl176th Pl 159th Ave SE157th Ave S E SE 177th S E 176th Pl 161st Ave SES E 179thSt St SE Petrovitsky Rd SE 177th St SE 179th Pl SESE 181st 147th AveSE 184th St145th Ave SE140th Ave SE135thSE 189th Pl134th Ave SESESE 183rd St SE 184th St Pl132nd Pl SESE 192nd St SE 192nd St140th Ave SESE 181st St SE 180th St 148th Ave SESE 186th St SE 180th Pl 188th124th Ave SE120th Ave SESE 188th St SE 184th St 127th Pl SE126th Pl SESE 180th St118th Ave SESE 179 St 131st Ave SEPl SE 185th Pl SE 192nd St 184th Pl 186th SE 190th St102nd Ave SE1 0 6 t h Av e SE108th Ave SE111th SE 192nd St SE 190th St 112th Ave SESE 182nd St SE 186th St SE 183rd Pl SE 186th Pl S 188th St 116th Ave SE108th Ave SES 179th St SE 181st St110th Ave SE109th Ave SE111th Ave SESE 180th Pl113th Pl SE114th Pl SEPl SEEast Valley RdSW 43rd St SW 41st St Talbot Rd S98t h Av e SE45th PlDavis Ave SS 55th StValley FreewayCarr RdS 43rd St S 192nd St 167 SW 27th St SW 30th St SW 29th St Lind Ave SWSW 39th St SW 34th St E Valley RdT alb ot Rd STalbot Crest Dr. SS 25th ST Whitworth Shattuck Ave SS 36th S 37th St Morris Ave SValley FreewayLind Ave SWS 31st S 32nd Pl 32ndS Smit h e r s S 28thS 26thTalbotRd SS 38th S 27th27thS 28th E Valley Rd167 104th Ave SEMill Ave S S 32nd Pl 515 SE 172nd St105th Ave SE106th Ave SEMill Ave SS 23r d St Ben s o n Dr SS 27th St Benson Rd SCedar Ave SSE 166th SE 168th St SE 169th St Petrovitsky Rd SE 116th Ave SE114th Ave SESE 164th St 109th Ave SE111th Ave SE113th Ave SESE 162nd St 115th Ave SE116th Ave SECarr Rd SE 172nd St SE 173rd St S 32nd St S 34th St Main Ave SSE 162nd SE 165th SE 169th PL127th Ave SESE 170th St SE 169th St SE 163rd St SE 161st St SE 163rd St SE 164th St 123rd Ave SE122nd Ave SESE 170th St 125th Ave SE124th Ave SE SE Petrovitsky Rd SE 172nd St SE 165th St122nd Ave SESE 168th St SE 167th St119th Ave SE121st Ave SE120th Ave SE126th Ave SE129th Ave SE128th Ave SE13 1st Ave S ESE 164th St SE 162nd Pl SE 164th S E SE 169th St SE 172nd St SE 176th St134th Ave SES E 1 7 2 n d S t133rd Pl SE132nd Pl SESE 163rd StSE Fairwood Blvd SE 173rd St SE Petrovitsky Rd135th Ave SE136th135th Pl SESE 160th Pl 140th Ave SES E 1 7 0 th S t1 7 1 s t P lSE 170th St 140th Pl SESE 161st Pl SE Fairwood Blvd SE 165th 174th141st163rd St 147th Ave SE145thSE 167th St 165th Pl 1 4 6 th A ve S E142nd Ave143r d Av e138th PlSE 1 7 1 s t P l S E 1 7 2 n d P l SE 161st Pl 132nd Pl SEAveS E SE St S E 167th St SE Fairwood Blvd SE 172n d P l 151st Ave SE155th Ave SESE 175th Ct 158th Ave SE 161st Ave SESE 173rd St SE 172nd Pl157th Pl SE154th Ave S E SE 1 69th S E 1 6 7 th P lFairwood Blvd Pl 162nd Ave SE162nd Pl SE163rd Pl SESE FairSE 1 69th 1 6 0 t h Pl SESE 160th Pl SE 164th Pl SE 166th158thSE Fairville Blvd 163rd Pl SESE 175th Pl SE 171 Pl wood BlvdSE Ren SE SE 145th S SE 147th St SE 149th St SE Renton - Maple Valley Hwy154th Pl SEAve SE149thJones Rd SE SE 145th Pl SE 146th Pl 161th Ave157 th Ave SE156th Ave SESE 148th St S E J o n e s R d156th Pl SE162ndSE 149th St Ave SE158thSESEth Pl145 135th AveSE 149th St SE 145th Pl.143rd Pl. SESE Renton - Maple Valley Hwy. 140th Way SE134th AveSESE 159th Pl SE 158th St 138th Pl SE130th Ave SESE 160th St118th Pl SESE 157th St Edmonds Way SE Beacon Way SE Ferndale Ave SE Glenwood Ave SE SE 158th St SE 160thKirkland SE 159th SE 18th 129th Pl Royal Index Ave SE Hills Dr SE Shelt onSE 11th St117th Ave SE119th Pl SESE 19th CtSE 20th Ct Pierce A v e SELk Youngs Way SESE16th S t SE 151st St Benson Rd SGrant Ave SPuget DrEagle Ridge Dr.S Puget Dr S 18th St S 18thGrant Ave S10thRenton Ave SHigh Ave. S9th Jones Ave. SSE 161st St SE 21st St EdmondsSE 19th D rPl Puget Dr SER o l li n g SE 16th Pl Hills AveS E SE8th 8 t h Lind Ave SWS 23rd St SW 19th St SW 21st St SW 16th St S W 1 2 t h S tS W 1 3 t h S tWhitworthSmithersMorrisS 21st St S 17th St Morris Ave S167 515 E Valley RdS 15th St Lake Ave SDavis Ave SS 18th Shattuck Ave SS 19th St Talbot Rd SS W G r a d y W a y S W 1 0 t h S tS Renton Village Pl Airport Way S Tobin StSeneca AveNW 2ndStevens Ave NWLind Ave NWMapleTaylor Ave NWHardie Ave NWS 132nd StRentonAve S S 134th St Victoria SW Langston Rd SW 3rd Pl 4th Pl SW 5th Ct SW 7th StStevens AveRai n i er Av e4 th P lS 7th St S 6th St Shattuck AveS3rd Pl Whitworth Ave SMorris Ave SSmithers Ave SS 2nd StLake Ave SLogan Ave SBurnett Ave S900Maple AveHardie Ave SWS 3rd St Burnett Ave SS 5th St H a rdie A v e S WSW 5th PlMonterey DrWells Ave SWilliams Ave SRenton Ave SCedar Ave SFactory Ave NW a y N BronsonN 2nd StPark Ave NPelly Ave NGarden Ave NMeadow Ave NN E 3 rd S tHouser W ay SS 2nd St Grady WayMaple Valley Hwy N 1st St N 3rd St Brooks F a ctory Pl N BlaineHouserAve NEMain Ave SSE 2nd Pl Union Ave SESE 6th SE 5th St SE 6th N E 3 rd S tNE 2nd St NE 4th St NE 3rd Ct Monroe Ave NEFerndaleNE 1st St Ferndale Glenwood Edmonds Ave SESE 5th Pl SE 5th St SE 3rd St Lynnwood S E 4th S tIndexInd ex Pl Harrington Glen wood SE 4 th S tGlenwood NE 2nd St SE 142nd St S E 1 4 1 s t S tS E 4 th S tS E 3 rd P l140th AveS E 4 th P l1st Pl SE 1st Pl SE 2nd Pl N E Bremerton Ave NEDuvall Ave NESE 139th Pl 146th Ave SE144th Ave SE145th Ave SE143rd Ave SE142nd Ave SE143rd Ave SELyons Ave NENE 2nd St Hoquiam Ave NE144th Ave SE147th Ave SEJericho Ave NENE 3rd StLyons SE 2nd Ct NE 2nd Ct Jericho Ave NENE 2nd St SE 2nd PlDuvall Ch e l a n Av e SE158th Ave. SE156th Ave. SERosarioSE 136th St. S E 1 4 2n d P l.SE 137th Pl. SE 144th St. SE 138th Pl. SE 139th Pl. SE 140th Pl. SE 143rd Pl.149th Pl. SE148th Pl. SESE 142nd St.154th Ave. SESE 143rd St. SE 138th Pl. SE 139th Pl.160th Ave. SE162nd Ave. SELane Liberty SE 132nd St. SE 133nd St. SE 134th St. SE 135th St. SE 132nd St. SE 130th St. SE 131st St.164nd Ave. SESE 2nd Ct NE 2nd St Orcas Ave NEQuincy165th Pl SE166th Pl SESE 120th SE Ren SE 113th St SE 113th Pl 152nd Ave SESE 113th St SE 124th St SE 120th St 150th Ave SE149th Ave SENE 4th St 155th Ave SESE 114th St SE 117th St SE 124th St 150th Ave SE164th Ave SE156th Ave SESE 116th St 160th Ave SE161st Ave SE163rd Ave SEQuincy Rosario NE 4th Pl 5th Pl NE 6th Pl SE 128th St Rosario PlShadow Ave NE 10th St NE 4th St NE 5th St NE 6th Pl Duvall Ave NENE 11th 10th St NE 10th Pl NE NE AnacortesFieldNE 9th Duvall Ave NENE 4th St 7th Pl SE 112th Pl Hoquiam NESt 146th148th Ave SENE 8th St NE 7th Pl NE 7th St NE 6th St Nile Ave NEHoquiam Ave NEIlwaco Ave NEJericho Ave NEDuvall Ave NENE 10th St Jericho PlNE 11th St 11th Pl. NE 8th St. NE 7th St. NE 10th NE 11th Sunset Ln.NE Sunset BL GlenwoodHarringtonPl. NEKirkland Ave. NEIn dex A ve. N ENE 4th Ferndale Edmonds NE 5th Ct. Ct.Ave.Index Pl. NECt.NE 4th St.Monroe Ave. NEI ndexN E 8 t h S t .7th S t.NE 10th St. Pl.NE 5th NE 6th Pl.NE 6 th St. NE 6thPl.Harrington Ave.NE Sunset NE 9th N E 9thLn. NELynnwood Ave.JeffersonMonroeJeffersonNE 6th NE 7th NEAve.St KirklandNE Pierce Ave. NEShel t onRedmond Ave.Olympia Ave. NENE 4th St. NE 8th Ct. NE 9th Ct.PierceOlympiaPl.Pl.6th Shelton Ave. NERedmond Ave.Ave. NESt.QueenNE 10th Ln. NE 10th Ct. NE 9 Ct. NE 10th 9th St. Pl. St. Ct. NE 11 11th Ct. NE 10 NE 6 Ct. NE 6th Pl.Ave. NETacoma NE 7th St.Ave. NE11th Pl.Park Ave. NGar den Av e . NN 8th St. N 6th St. N 5th St.Garden Ave. NPark Ave. NPelly Ave. NWells Ave. NWilliamsAve. NN 4th St.Hous er Way NAberdeenAve. NESunset Blvd. NENE 10th Pl.NE 10th St. NE 8th Pl. NE 9th PL NE 9th St. NE 7th NE 6th Pl.Camas Ave.Dayton Ave.AberdeenC a m asAve.Blaine Ave.G randeyWayW in d s o r WayBronsonEdmonds Ave NED ayto nAve. l900 900l WayN ENENEAve. NEMontereyN 10th St. T a ylor Pl. N WSenecaN W 5 th St . Pl.Stevens Ave. NELindNW 7th St. 6th St.N W Ni shi waki LaneN 6th St.Rai ni er Ave. N124th St. 123rd 123rd St. 122nd St. S 121st St. S 120th St. S 119th St. S 118th St. S 117th Pl. S 117th St. S 116th St. S 115th Pl. S 115th St. S 114th St. S 113th St. S 125th St. S 121st St. NE 12th St. 14th NE 16th St.Aberdeen Ave. NENE 20th St.Jones Ave. NENE 24th St.Meadow Ave. NEN 26th St.Lak e Wa s hi n gt on. Bl v d NLincolnMontereyNE 23rdMonterey DaytonBlaine Ave. NEKennewickNE 22nd DaytonNE 27th St.Edmonds Ave. NE GardenN 24thCt.Aberdeen Ave. NEKennewickCamasDaytonDaytonNENE 17th St NE 17th SE 98th St SE 100th St Newpor t Ct NE 21st St NEJefferson AveHarringtonIndex AveAveNE 23rd St NE 20th NE16th St NE Sunset BlvdKirkland AveNEMonroe AveNewportKirkland Pl NE 120t h Pl SENE 23rd Pl NE 24th St NE 27th St SE 96th St Queen Ol ympi a 126t h Ave SENE 22nd Pl NE 12th St NE 22nd St NE 21st St NE 14th St Pierce PlQueen Pl Union Ave NENE 23rd Pl Union Ave NE128th Ave Ave NENE 23rdNE 22nd PlQueen NE 19th Shelton Ave NEAve NERedmondNE 25th PlNE 25th Pl SE 102nd NE 21st NE 20th Ilwaco Ave NEField Ave NENE 23rd NE 17th NE 21st NE 24th NE 25th Pl NE 22nd VashonAveW h it m a n NE 19th St AnacortesNE 18TH Cir NE 21st Pl NE 19th St NE 26th Ct NE 25th Ct Hoquiam Ave NE147th AveDuvall Ave NENE 24th StNE 24th NE 24th NE 23rd NE 25th Pl NE 22nd N E SunsetBlvdDuvall Ave NENE 22nd Pl NE 20th Anacortes Ave NESE 104th NE 17th SE 107th Pl NE 19th St VashonVashonVashonCt NECt NEWhitmanAve NENE 23Ct CtNE 20 AnacortesNENE Sunset Blvd.148th Ave SENile Ave NE21st Ct NE 22nd Ct NE 23rd Ct NE 24th CtLyons AveNE 26th St SE 104th St, Issaquah Rd.151st Ave. SESE May Valley Rd SE 112th S E 1 0 3 t h S t 98th Ave. S198th PlTalbot Rd S99th Pl SS 203rd StS 203rd Pl S 202nd St S 200th St S 199 th St 98th103rd Pl SESE 199th 105th Ave SE104th Ave SE104th Ave SESE106th Ave SE106th Ave SESE107th AveSE 200th St 204th SE 196th St SE 200th St 116th Ave SE104th Pl SE106th Ave SESE 202nd Pl SE 203rd Pl SE 200th St 121st PlSE 200th St121st Ave SESE 1 1 7 t hPl SESE 196th St 122nd199th SE 201st StPl SE124th Ave SESE 198th St SE 201st SE 196th St 198th SE 196th Pl 137th Ave SE134th Ave SE136th Pl SE135th Ave SESE 202nd St. SE 201st St.140th Ave SE138th Ave SESE 200th St143rd Pl SE142nd Pl SES E 146th Ave SESt133rd Ave SES 182nd 80th Ave. S80th80th Ave. SPl.SSW 43rd St. 181st SW 41st St.OakesdaleSW 43rd St.Valley Hwy.72nd Ave Sl 181 West S 190th St S 188th St S 186th St S 190th St S 188th St S 192nd St Minkler Blvd 70th Ave SSW 39th StOakesdale Ave SWSW 27th St SW 34th StWest Valley HwyPowell Ave. SWThomas Ave. SWG rady W ayMonster Rd.SW 16th St.Oakesdal e Ave. SWSW 12 th St. l181Fort Dent WayI n t e r u r b a n A v e SS 144th St 6 5 t h Av e S59th Ave SS 153rd St 62nd Ave SS 153rd St S 147th St 60th S 149th St S 151st Southcenter B lv d Andover Pk WAndover Pk ETukwila Pkwy 405 68th Ave S65th Ave S64th Ave SS 129th St Martin Luther King Way 59th Pl S S 143rd St S 143rd PlBeacon Coal Mine RdMartin Luther King Way Ave SMonster Rd SW Thomas AvePowell Ave SWSW 4th Pl S 140th St 81st Ave S80thS 129th St S 135th St S 129th Pl S 130th St S 133rd St 72nd Ave S74th Ave S69th Ave SRenton Ave LangstonS Langston Rd S 130th St S 134th St S 132nd St 80th Ave S76th Ave SS S 84th Ave S82nd Ave S83rd Ave SS 123rd Pl S 122nd St S 121st St Ave S R ento n S 126th St 7 4 th P l S S 1 2 7 th S tS 126 th S tS 125th StS 118th St 75t h Ave S69th Ave SRenton S 120th Pl 72nd Ave SS 118th Pl S 116th St Ave S S 115th Pl S 116th St S 125th St S 117th St 82nd79th Ave S76th Ave S76th Ave S78th Ave S77th Ave S77th Ave SS 122nd St S 124th St S 123rd St S 116th Pl S 114th St 70th Pl S80th Ave S70th Ave SS 124th Pl S 124th St78th Ave SR enton Ave SS 120th St S 115th St S 114th St S 113th St 84th Ave SBeacon Ave S64th Ave S66th Ave S59th Ave S67th AveS 124th Ave 62nd Ave S61st Ave S64th Ave S60th Ave SS 122nd St S 125th St S 124th St S 119th St S 120th St Pl SS 127th Pl 64th59th Ave S60th Ave SS 117th St S 118th St S 117th Pl S 118th Pl 57th Ave SS 112th St Rainier Ave S Forest Ave Forest Ave Sunny Lake Ridge Mission Dr Dixon Dr Dixon 76th Ave SLaurel Garden Pl LotusPl80thStRainier Ave S Ryan St Dr Crest ³ 0 1,400 2,800 ' City of Renton Sensitive AreasLiquefaction Hazards This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best information available as of the date shown. This map is intended forCity display purposes only. HAZARD CONDITION Liquefaction Susceptibility high moderate to high low to moderate Public Works DepartmentG. Zimmerman, AdministratorTechnical ServicesR. MacOnie, D. Visneski Printed on May 20, 2009Data Source: Public Works, Utilities Systems, Technical Services;Washington State Department of Natural Resources, Geology and Earth Resources Division Critical Infrastructure ^_Police Department Fire Stations ®v Valley Medical Center n Schools Renton City Limits PROJECT SITE ^_ ³ 0 1,500 3,000 ' City of Renton Sensitive AreasSeismic Hazards This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best information available as of the date shown. This map is intended forCity display purposes only. Hazard Condition High Seismic Severity Public Works DepartmentG. Zimmerman, AdministratorTechnical ServicesR. MacOnie, D. Visneski Printed on May 21, 2009 Data Source: Public Works, Utilities Systems, Technical Services Critical Infrastructure ^_Police Department Fire Stations ®v Valley Medical Center ¹¹Schools PROJECT SITE k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkD r SW 7th St SE 128th St SE 192nd StLindAveSWMainAveSS 132nd St Factory PlN Talbot Rd SN 3rd St RainierAveS 164thAveSETukwila Pk w y SPuget Dr NE 4th St S 3rd St S 1 2 9 th S t68thAveSSWSunsetBlvd SW 16th St 116thAveSEN 4th St I n t e r u r b a n Av e S WilliamsAveNBronsonW a y N NE7thSt 124thAveSES 7th St SERenton IssaquahRd Rai ni er AveNNewcastle Way CoalCr e e k PkwySESW 41st St T a ylo r P l N WNESunsetBlvdWellsAveNUnionAveNEN E 3 rd S tHa r die A v eSWS180th St Maple Valley Hwy 140thAveSES G ra d yWayS 2 1 s tSt BensonRdSRe nt o n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrR d SE 168th St Beaco n A v e S 68thAveSLoganAveN108thAveSEForestDr SE S2ndSt 141 s tAve S ERainierAveS 156thAveSES E 183rd StBenson Dr SS 124th StS 43rd St Airport Way S W G radyW a y S E J o n e s RdSunsetBlvdN Puget Dr SESE 204th W aySW 34th StMo n s ter RdSW S E 1 4 2 n d P lWestValleyHwySSEMay ValleyRd SunsetBlvdNS C a r r RdHouserWayNNewcastle GolfClubRd S 133rd St WilliamsAveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAveSWestVal leyHwyWestValleyHwyParkAveN108thAveSE6 6 t h Av e SWMercerWayWMercer W ay LakemontBlvdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of RentonSensitive Areas 0 0.5 10.25 Miles Information Technology - GISmapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended forCity display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Landslide HazardSeverityVery HighHighModerateUnclassified Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN PROJECT SITE k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkD r SW 7th St SE 128th St SE 192nd StLindAveSWMainAveSS 132nd St Factory PlN Talbot Rd SN 3rd St RainierAveS 164thAveSETukwila Pk w y SPuget Dr NE 4th St S 3rd St S 1 2 9 th S t68thAveSSWSunsetBlvd SW 16th St 116thAveSEN 4th St I n t e r u r b a n Av e S WilliamsAveNBronsonW a y N NE7thSt 124thAveSES 7th St SERenton IssaquahRd Rai ni er AveNNewcastle Way CoalCr e e k PkwySESW 41st St T a ylo r P l N WNESunsetBlvdWellsAveNUnionAveNEN E 3 rd S tHa r die A v eSWS180th St Maple Valley Hwy 140thAveSES G ra d yWayS 2 1 s tSt BensonRdSRe nt o n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrR d SE 168th St Beaco n A v e S 68thAveSLoganAveN108thAveSEForestDr SE S2ndSt 141 s tAve S ERainierAveS 156thAveSES E 183rd StBenson Dr SS 124th StS 43rd St Airport Way S W G radyW a y S E J o n e s RdSunsetBlvdN Puget Dr SESE 204th W aySW 34th StMo n s ter RdSW S E 1 4 2 n d P lWestValleyHwySSEMay ValleyRd SunsetBlvdNS C a r r RdHouserWayNNewcastle GolfClubRd S 133rd St WilliamsAveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAveSWestVal leyHwyWestValleyHwyParkAveN108thAveSE6 6 t h Av e SWMercerWayWMercer W ay LakemontBlvdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of RentonSensitive Areas 0 0.5 10.25 Miles Information Technology - GISmapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended forCity display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Aquifer Protection Zone 1 Zone 1 Modified Zone 2 Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN PROJECT SITE k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkD r SW 7th St SE 128th St SE 192nd StLindAveSWMainAveSS 132nd St Factory PlN Talbot Rd SN 3rd St RainierAveS 164thAveSETukwila Pk w y SPuget Dr NE 4th St S 3rd St S 1 2 9 th S t68thAveSSWSunsetBlvd SW 16th St 116thAveSEN 4th St I n t e r u r b a n Av e S WilliamsAveNBronsonW a y N NE7thSt 124thAveSES 7th St SERenton IssaquahRd Rai ni er AveNNewcastle Way CoalCr e e k PkwySESW 41st St T a ylo r P l N WNESunsetBlvdWellsAveNUnionAveNEN E 3 rd S tHa r die A v eSWS180th St Maple Valley Hwy 140thAveSES G ra d yWayS 2 1 s tSt BensonRdSRe nt o n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrR d SE 168th St Beaco n A v e S 68thAveSLoganAveN108thAveSEForestDr SE S2ndSt 141 s tAve S ERainierAveS 156thAveSES E 183rd StBenson Dr SS 124th StS 43rd St Airport Way S W G radyW a y S E J o n e s RdSunsetBlvdN Puget Dr SESE 204th W aySW 34th StMo n s ter RdSW S E 1 4 2 n d P lWestValleyHwySSEMay ValleyRd SunsetBlvdNS C a r r RdHouserWayNNewcastle GolfClubRd S 133rd St WilliamsAveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAveSWestVal leyHwyWestValleyHwyParkAveN108thAveSE6 6 t h Av e SWMercerWayWMercer W ay LakemontBlvdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of RentonSensitive Areas 0 0.5 10.25 Miles Information Technology - GISmapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended forCity display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Steep Slopes Percent Range >15% & <=25% >25% & <=40% >40% & <=90% >90% Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN PROJECT SITE Kin g C ounty King C ounty iMap Dr ain a ge C om plaints Date: 3/1/2017 Notes: The i nfor ma tion inclu ded on thi s map has been c om pil ed by King Cou nty s taff from a vari ety of so urc es a n d is subject to c ha n ge w ith out n otice. King C ountymakes n o r epr e sentations o r w ar ra ntie s, express o r i mp li ed , as to acc ur a cy, co m pl ete ness, tim e line ss, or ri g hts to the use of s uc h i nform a tion . T hi s doc um e n t i snot intended for us e as a su rvey pr odu ct. King C ounty shall not be l iabl e for an y gene r al , spec ia l, in dire ct, inci de n ta l, or conse que ntia l dam a ges i nclu d in g,but n ot li mi ted to, lost reve n ues o r l os t p r ofi ts resulting fro m the use or mi suse of the i nfor ma tion contained on this m ap. An y s al e of this m ap or in form atio n onthis map is prohibited ex cept by wr itten pe r mis sion of King Cou n ty. Leg end Pa rc els Bo nd ed Co mmer cia l-MF Co mmer cia l-SF Co nstr uct io n DOT FMD Re gion al Re sid ential Dr aina ge comp lain ts PROJECT SITE 1/4 MILE DOWN STREAM FLOW PATH 36,112 3,009 Black River Drainage Basin This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. None 1/25/2017 Legend 2,04601,023 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 2,046 WGS_1984_Web_Mercator_Auxiliary_Sphere Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Other City of Renton Wellhead Protection Area Zones Zone 1 Zone 1 Modified Zone 2 Special Flood Hazard Areas (100 year flood) Slope City of Renton >15% & <=25% >25% & <=40% (Sensitive) >40% & <=90% (Protected) >90% (Protected) Slope King County >15% & <=25% >25% & <=40% >40% & <=90% >90% Drainage Sub Basin <all other values> Black River Boren Creek Cabbage Creek Cedar Grove Cedar Main Urban China Creek PROJECT SITE Job No. RVAC0000-0002 Page 4-1 March 21, 2017 4 FLOW CONTROL AND WATER QUALITY DESIGN 4.1 PERFORMANCE STANDARDS As mentioned in Section 2 – Conditions and Requirements Summary, the project is required to comply with Core Requirements #1-9 and applicable Special Requirements of the 2017 City of Renton Surface Water Design Manual (2017 COR SWDM). Per the 2017 COR SWDM, the project is subject to Enhanced Basic Water Quality and Peak Rate Flow Control Standard. Research on the City of Renton GIS Maps, provided information for the site as a guide for applying the Area-Specific Flow Control Facility Requirements. The site is located within the Peak Rate Flow Control Standard – Matching Existing for flow control facility requirements under the 2017 COR SWDM. Please see the Flow Control – ExistPeak Map provided by the City of Renton GIS, at the end of this section. Section 1.2.3.1.A. Area-Specific Flow Control Facility Requirements of the 2017 COR SWDM under the Exceptions heading, states that, “sites located within the Peak Rate Flow Control Standard Areas may be waived for any threshold discharge area of a redevelopment project in which all of the following criteria are met:” Existing Conditions land cover were analyzed using a current survey prepared by Triad (basis for the Existing Conditions Exhibit). Proposed Developed Conditions land cover and disturbance limits were analyzed from a preliminary site plan prepared by Triad and Fuller 2 Job No. RVAC0000-0002 Page 4-2 March 21, 2017 Sears Architects (basis for the Developed Conditions Exhibit). Using the latest version of the Western Washington Hydrology Model (WWHM 2012), peak 100-yr runoff was modeled for each condition. Results indicate that the proposed/replaced impervious and pervious targeted surfaces will generate a 0.053 cfs (<0.15 cfs) increase in the existing site condition 100-year peak flows. Please see the calculations, exhibit(s) and WWHM 2012 documentation at the end of this section. As for the second criterion b, given the negligible change in peak runoff and the relative good condition of the existing receiving system, this project is not expected to adversely impact critical areas or cause downstream severe flooding or erosion problems. Flood Problem Flow Control Research on the City of Renton GIS Maps provided information for the site as a guide for applying the Flood Problem Flow Control Standard Areas requirements. Even though there are no documented issues immediately downstream of the site, since the site includes portions of a regulated flood zone, the City has determined that a higher than average level of flow control is required to prevent aggravation of existing documented flooding problems. A copy of the GIS Map has been attached at the end of this section and is labeled, “City of Renton Flood Hazard”. Section 1.2.3.1.C. Flood Problem Flow Control Standard Areas within the 2017 COR SWDM under the Exceptions heading, states: The Exception requirements for the Area Specific Flow Control and Flood Problem Flow Control Standard Area requirements are the same. Therefore, the results from the WWHM 2012 attached to this report show that the site meets the exception requirements for both Peak Flow Control and Flood Problem Flow Control. Job No. RVAC0000-0002 Page 4-3 March 21, 2017 The Enhanced Basic Water Quality treatment standard is required for this project. This is because 50% or more of the runoff from the site is from a multifamily land use. Since the redevelopment of the site involves the addition plus replacement of more than 5,000 sf of pollution generating impervious surface (i.e. pavement) then the Enhanced Basic WQ Standard must be applied. The treatment goal for facility options in the Enhanced Basic WQ menu is to accomplish better removal of heavy metals and potentially other toxic materials. 4.2 EXISTING CONDITIONS As discussed in the Executive Summary, the existing property is comprised of a movie theater with associated parking and roadways. Rolling Hills Creek runs though the southern portion of the site from east to west. The site is surrounded to the north and east by parking lots, the Evergreen office building to the west, and I-405 to the south. See the Existing Basins Exhibit located at the end of this section for reference. Topography on the site is variable and ranges from a low point at 20 feet to a high point of about 30 feet. The northern portion of the site slopes gradually to the north with grades of 1-5% while the southern half gradually slopes south until the steeper banks of the Rolling Hills Creek that range from 25-50%. The existing project site consists of a single Threshold Discharge Area (TDA), in which the surface water and on-site storm drainage system combine within one-quarter mile downstream. Under existing conditions, on-site runoff sheet flows either north or south and is collected via on-site catch basins. The TDA consists of a large portion of the existing development north of the project site up to and including a portion of S Grady Way. The upstream portion of the TDA, or Upstream Drainage Basin (UDB), is collected by an existing storm drain system that connects to the on-site system in the northeast corner of the site. The runoff for Threshold Discharge Area, which includes the Project Boundary Basin (PBB), is conveyed to an existing oil/water separator located on the east side of the existing theater. The runoff is then discharged into the Rolling Hills Creek in the southeast portion of the site. The boundaries for the basins mentioned above are shown on the Upstream Basin Job No. RVAC0000-0002 Page 4-4 March 21, 2017 Exhibit, Existing Conditions Exhibit, and the Total Threshold Discharge Area Exhibit at the end of this section. The areas used in the modeling of the existing conditions consist of on-site area and portions of the neighboring properties creating a total Project Boundary area of 2.41 acres and the Upstream Basin area of 16.46 acres. The existing conditions were modeled as shown below: Project Boundary Areas C, Lawn, Flat = 0.38 acres Roads, Flat = 1.18 acres Roof Tops, Flat = 0.85 acres Total = 2.41 acres The existing Project Boundary area yields the following peak flows: Return Period Flow (cfs) 2 year 0.798281 5 year 1.016851 10 year 1.166319 25 year 1.361191 50 year 1.511009 100 year 1.665003 Upstream Basin Areas A B, Lawn, Flat = 2.04acres Roads, Flat = 14.42 acres Total = 16.46 acres The existing Upstream Basin yields the following peak flows: Return Period Flow (cfs) 2 year 3.698339 5 year 4.650681 10 year 5.308737 25 year 6.173636 50 year 6.843339 100 year 7.535661 Job No. RVAC0000-0002 Page 4-5 March 21, 2017 4.3 DEVELOPED CONDITIONS As discussed in the Executive Summary, the developed project site proposes to construct an apartment building providing 270 units with parking and frontage improvements, along with on-site water, sewer, stormwater and dry utilities. See the Developed Conditions Exhibit located at the end of this section for reference. The exiting storm conveyance system (and oil/water separator) will be re-routed around the proposed building, but will continue to discharge flow to Rolling Hills Creek using the existing outfall. Additional collection and conveyance elements will serve new/disturbed pavement and landscape areas. These elements will route flows through a new Modular Wetland treatment facility prior to connection to the main system downstream of the oil/water separator. Below is the tributary area for the project boundary. Project Boundary Areas: C, Lawn, Flat = 0.28 acres Roads, Flat = 0.99 acres Roof Tops, Flat = 1.14 acres Total = 2.41 acres The proposed total project boundary yields the following peak flows: Return Period Flow (cfs) 2 year 0.830063 5 year 1.054608 10 year 1.207859 25 year 1.40735 50 year 1.560509 100 year 1.717769 4.4 DETENTION FACILITY ANALYSIS The peak flows shown previously for the 100-year storm events for the existing and developed conditions are 1.665 cfs and 1.718 cfs respectively. These Results indicate that the proposed/replaced impervious and pervious targeted surfaces will generate a 0.053 cfs (<0.15 cfs) increase in the existing site condition 100-year peak flows. Therefore, the site Job No. RVAC0000-0002 Page 4-6 March 21, 2017 meets the exception requirements and is exempt from having to provide on-site detention/flow control. 4.5 FLOW SPLITTER DESIGN A flow splitter is proposed on-site, and will be located after the existing oil/water separator and before the proposed Modular Wetland facility. The flow splitter will provide specific area tributary flow either to the Modular Wetland (on-site stormwater generated flows) or directly to Rolling Hills Creek (off-site stormwater generated flows). The intent of this design element is to direct an appropriate amount of runoff to the new Modular Wetland facility for treatment. The amount of runoff treated shall be equivalent to the amount of runoff generated from all non-roof areas disturbed by the project. The components and design for the flow splitter will be provided at the final engineering phase of the project. 4.6 WATER QUALITY FACILITY ANALYSIS The Enhanced Basic Water Quality treatment standard will be met for the Project Basin through the use of a Modular Wetland biofiltration vault. Modular Wetland has received the General Use Level Designation (GULD) as a stand-alone facility for Enhanced and Phosphorus treatment standards from the Department of Ecology. A facility design will be provided at Final Engineering. A Modular Wetland facility detail from a project of similar size can be seen for reference at the end of this section. 9,028 752 Flow Control - ExistPeak This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. None 1/25/2017 Legend 5120256 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 512 WGS_1984_Web_Mercator_Auxiliary_Sphere Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Other City of Renton Parcels Flow Control Application Peak Rate (Existing) Flow Control Duration (Existing) Flow Control Duration (Forested) Flood Problem Flow PROJECT SITE 4,514 376 City of Renton Flood Hazard Area This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. None 1/26/2017 Legend 2560128 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 256 WGS_1984_Web_Mercator_Auxiliary_Sphere Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Other City of Renton Addresses Parcels Floodway Special Flood Hazard Areas (100 year flood) PROJECT SITE WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: 17-0126 Ex vs. Dev Site Name: Site Address: City: Report Date: 3/14/2017 Gage: Seatac Data Start: 1948/10/01 Data End: 2009/09/30 Precip Scale: 1.00 Version Date: 2016/02/25 Version: 4.2.12 ___________________________________________________________________ Low Flow Threshold for POC 1: 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name: Basin 1 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 0.38 Pervious Total 0.38 Impervious Land Use acre ROADS FLAT 1.18 ROOF TOPS FLAT 0.85 Impervious Total 2.03 Basin Total 2.41 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name: Basin 1 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 0.28 Pervious Total 0.28 Impervious Land Use acre ROADS FLAT 0.99 ROOF TOPS FLAT 1.14 Impervious Total 2.13 Basin Total 2.41 Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area: 0.38 Total Impervious Area: 2.03 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area: 0.28 Total Impervious Area: 2.13 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow (cfs) 2 year 0.798281 5 year 1.016851 10 year 1.166319 25 year 1.361191 50 year 1.511009 100 year 1.665003 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow (cfs) 2 year 0.830063 5 year 1.054608 10 year 1.207859 25 year 1.40735 50 year 1.560509 100 year 1.717769 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 1.058 1.092 1950 1.092 1.143 1951 0.659 0.682 1952 0.561 0.588 1953 0.606 0.635 1954 0.650 0.675 1955 0.731 0.762 1956 0.721 0.751 1957 0.833 0.863 1958 0.656 0.684 1959 0.656 0.688 1960 0.680 0.702 1961 0.707 0.734 1962 0.601 0.628 1963 0.685 0.710 1964 0.650 0.681 1965 0.862 0.891 1966 0.562 0.586 1967 0.973 1.013 1968 1.108 1.152 1969 0.784 0.811 1970 0.745 0.774 1971 0.889 0.923 1972 0.949 0.976 1973 0.538 0.564 1974 0.818 0.848 1975 0.904 0.949 1976 0.633 0.657 1977 0.659 0.691 1978 0.808 0.847 1979 1.109 1.162 1980 1.065 1.093 1981 0.831 0.865 1982 1.188 1.232 1983 0.942 0.984 1984 0.603 0.628 1985 0.831 0.864 1986 0.710 0.741 1987 1.091 1.141 1988 0.655 0.687 1989 0.819 0.859 1990 1.522 1.552 1991 1.191 1.222 1992 0.598 0.622 1993 0.510 0.533 1994 0.546 0.573 1995 0.734 0.765 1996 0.809 0.835 1997 0.778 0.805 1998 0.764 0.797 1999 1.613 1.668 2000 0.793 0.823 2001 0.848 0.887 2002 1.038 1.071 2003 0.806 0.832 2004 1.503 1.557 2005 0.688 0.712 2006 0.613 0.633 2007 1.411 1.459 2008 1.170 1.200 2009 1.001 1.050 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 1.6125 1.6683 2 1.5221 1.5567 3 1.5030 1.5524 4 1.4106 1.4593 5 1.1910 1.2316 6 1.1879 1.2218 7 1.1698 1.2002 8 1.1091 1.1615 9 1.1080 1.1523 10 1.0920 1.1431 11 1.0913 1.1413 12 1.0648 1.0935 13 1.0576 1.0924 14 1.0377 1.0710 15 1.0014 1.0504 16 0.9735 1.0127 17 0.9486 0.9841 18 0.9419 0.9763 19 0.9041 0.9485 20 0.8885 0.9234 21 0.8619 0.8914 22 0.8478 0.8873 23 0.8329 0.8648 24 0.8307 0.8641 25 0.8306 0.8626 26 0.8188 0.8591 27 0.8184 0.8481 28 0.8090 0.8472 29 0.8084 0.8345 30 0.8064 0.8322 31 0.7927 0.8231 32 0.7841 0.8112 33 0.7780 0.8048 34 0.7636 0.7973 35 0.7447 0.7739 36 0.7343 0.7651 37 0.7310 0.7616 38 0.7209 0.7505 39 0.7096 0.7413 40 0.7071 0.7336 41 0.6883 0.7125 42 0.6845 0.7102 43 0.6802 0.7022 44 0.6594 0.6911 45 0.6589 0.6881 46 0.6563 0.6870 47 0.6559 0.6844 48 0.6548 0.6815 49 0.6499 0.6806 50 0.6497 0.6755 51 0.6335 0.6566 52 0.6132 0.6346 53 0.6063 0.6332 54 0.6034 0.6281 55 0.6010 0.6275 56 0.5977 0.6216 57 0.5621 0.5876 58 0.5612 0.5856 59 0.5464 0.5733 60 0.5378 0.5642 61 0.5105 0.5331 ___________________________________________________________________ Stream Protection Duration POC #1 Facility FAILED duration standard for 1+ flows. Flow(cfs) Predev Mit Percentage Pass/Fail 0.3991 1741 2035 116 Fail 0.4104 1592 1837 115 Fail 0.4216 1448 1663 114 Fail 0.4328 1298 1529 117 Fail 0.4441 1167 1373 117 Fail 0.4553 1062 1242 116 Fail 0.4665 973 1131 116 Fail 0.4778 900 1035 115 Fail 0.4890 824 948 115 Fail 0.5002 749 878 117 Fail 0.5115 686 805 117 Fail 0.5227 638 745 116 Fail 0.5339 592 686 115 Fail 0.5451 549 624 113 Fail 0.5564 511 588 115 Fail 0.5676 465 548 117 Fail 0.5788 431 510 118 Fail 0.5901 398 463 116 Fail 0.6013 371 434 116 Fail 0.6125 352 403 114 Fail 0.6238 328 380 115 Fail 0.6350 305 353 115 Fail 0.6462 283 328 115 Fail 0.6575 261 309 118 Fail 0.6687 247 286 115 Fail 0.6799 228 274 120 Fail 0.6911 213 248 116 Fail 0.7024 201 232 115 Fail 0.7136 188 215 114 Fail 0.7248 175 208 118 Fail 0.7361 162 193 119 Fail 0.7473 151 182 120 Fail 0.7585 145 166 114 Fail 0.7698 136 160 117 Fail 0.7810 125 150 120 Fail 0.7922 118 138 116 Fail 0.8035 112 132 117 Fail 0.8147 105 124 118 Fail 0.8259 99 116 117 Fail 0.8371 92 107 116 Fail 0.8484 84 104 123 Fail 0.8596 82 99 120 Fail 0.8708 79 93 117 Fail 0.8821 77 85 110 Pass 0.8933 72 81 112 Fail 0.9045 69 79 114 Fail 0.9158 63 76 120 Fail 0.9270 61 71 116 Fail 0.9382 59 67 113 Fail 0.9495 54 62 114 Fail 0.9607 52 61 117 Fail 0.9719 51 59 115 Fail 0.9832 48 55 114 Fail 0.9944 46 52 113 Fail 1.0056 42 52 123 Fail 1.0168 40 49 122 Fail 1.0281 38 47 123 Fail 1.0393 35 44 125 Fail 1.0505 33 40 121 Fail 1.0618 29 38 131 Fail 1.0730 27 33 122 Fail 1.0842 25 32 128 Fail 1.0955 23 30 130 Fail 1.1067 21 28 133 Fail 1.1179 16 26 162 Fail 1.1292 16 24 150 Fail 1.1404 15 22 146 Fail 1.1516 14 19 135 Fail 1.1628 12 16 133 Fail 1.1741 11 15 136 Fail 1.1853 10 13 130 Fail 1.1965 8 12 150 Fail 1.2078 8 11 137 Fail 1.2190 8 10 125 Fail 1.2302 8 9 112 Fail 1.2415 8 8 100 Pass 1.2527 8 8 100 Pass 1.2639 8 8 100 Pass 1.2752 8 8 100 Pass 1.2864 8 8 100 Pass 1.2976 8 8 100 Pass 1.3089 8 8 100 Pass 1.3201 8 8 100 Pass 1.3313 8 8 100 Pass 1.3425 7 8 114 Fail 1.3538 6 8 133 Fail 1.3650 6 8 133 Fail 1.3762 6 8 133 Fail 1.3875 6 6 100 Pass 1.3987 6 6 100 Pass 1.4099 6 6 100 Pass 1.4212 5 6 120 Fail 1.4324 5 6 120 Fail 1.4436 4 6 150 Fail 1.4549 4 6 150 Fail 1.4661 4 5 125 Fail 1.4773 3 5 166 Fail 1.4885 3 4 133 Fail 1.4998 3 4 133 Fail 1.5110 2 4 200 Fail _____________________________________________________ The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. ___________________________________________________________________ Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. ___________________________________________________________________ LID Report LID Technique Used for Total Volumn Volumn Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volumn Volumn Volumn Water Quality Treatment Facility (ac-ft.) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by: Clear Creek Solutions, Inc. 2005-2017 All Rights Reserved. Via 405 Apartments – Triad Job # RVAC0000-0002 Existing Upstream Basin Tributary Area – 100-Year Peak Flows PREDEVELOPED LAND USE Name: Basin 1 Bypass: No Ground Water: No Pervious Land Use acre A B, Lawn, Flat 2.04 Pervious Total 2.04 Impervious Land Use acre ROADS FLAT 14.42 Impervious Total 14.42 Basin Total 16.46 ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Flow Frequency Return Periods for Pre-developed. POC #1 Return Period Flow (cfs) 2 year 3.698339 5 year 4.650681 10 year 5.308737 25 year 6.173636 50 year 6.843339 100 year 7.535661 Job No. RVAC0000-0002 Page 5-1 March 21, 2017 5 CONVEYANCE SYSTEM ANALYSIS & DESIGN To be addressed at the final engineering stage. Job No. RVAC0000-0002 Page 6-1 March 21, 2017 6 SPECIAL REPORTS AND STUDIES 6.1 FLOOD HAZARD DATA As mentioned previously, a portion of the project site lies within the 100-year FEMA flood boundary and can be seen on the Flood Hazard Data Exhibit at the end of this section. Proposed site improvements will affect the existing 100-year floodplain, as new grading patterns are required to accommodate the proposed multi-family apartment building. A requirement for new construction within the flood boundary is to maintain the current floodplain storage volume. The floodplain storage volume within the project boundary is the volume below the Base Floodplain Elevation (BFE) of 27.6 and the existing surface. The existing floodplain storage volume is 32,649 cubic feet. The proposed project improvements will realign the BFE boundary within the project site, while increasing the floodplain storage volume to 35,935 cubic feet. To see the existing and proposed floodplains, refer to the Flood Hazard Data Exhibit at the end of this section. 6.2 GEOTECH REPORT Golder Associates Inc. (Golder) prepared a geotechnical report entitled Geotechnical Report Via 405 Apartments on March 20, 2017. The report is attached at the end of this section. 6.3 STREAM STUDY David Evans and Associates, Inc. (DEA) prepared a stream study on February 2, 2017. The study is attached at the end of this section. N Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation A wor ld ofcapabilities delivered locally GEOTECHNICAL REPORT VIA 405 APARTMENTS Submitted To: Mr. Craig Koeppler, Vice President RVA Cinema LLC Parkway Capital, Inc. 520 Pike Street, Suite 1500 Seattle, WA 98101 Submitted By: Golder Associates Inc. 18300 NE Union Hill Road, Suite 200 Redmond, WA 98052 March 20, 2017 Project No.: 1771669.100 REPORT March 2017 ES-1 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx EXECUTIVE SUMMARY Golder Associates Inc. (Golder) is pleased to present the results of our geotechnical investigation to RVA Cinema LLC Parkway Capital for the design of the Via 405 Apartment building proposed at 25 South Grady Way in Renton, Washington (Site). The building will contain a two level concrete parking podium with six levels of wood-frame residential units above. The residential units will wrap around a central courtyard. No below grade structures are planned. The new development will be built on the footprint of an existing cinema building which was constructed around 1988. The following executive summary is intended to provide an overview of the geotechnical report and findings. Please refer to the main body of the report for detailed recommendations. Golder reviewed the previous geotechnical report prepared by GeoEngineers following the July 1987 geotechnical investigation for the existing cinema building. Geotechnical explorations consisted of four boreholes located at the north, east, and south sides of the Site. The boreholes were advanced through alluvium to bedrock. The cinema building was constructed on a timber pile supported foundation. For this report Golder contracted InSitu Engineering to conduct four Cone Penetration Tests (CPTs) to complement the previous boreholes. The CPT explorations were advanced to bedrock and completed in February 2017. The general soil profile consists of about 2.5 to 7 feet of fill (medium dense to dense sand and silty sand) overlaying alluvial deposits. The alluvium consists of a non-liquefiable soft to very stiff silt and organic silt layer with the variable thickness of 0.5 to 12 feet overlaying a medium dense liquefiable sand layer. The alluvial deposit is underlain with varying thickness of highly weathered sandstone in the form of medium dense to very dense fine or fine to medium sand. Moderately hard sandstone was encountered at depths of 13 to about 48 feet, generally sloping down from southeast to northwest of the site. Groundwater levels were measured at 11, 8.5, 8.5, and 5.5 feet below the ground surface in Borings B-1, -2, -3, and -4, respectively, in July 1987. Golder relied on the groundwater information from the 1987 boreholes, since the CPT data was inconclusive to determine groundwater level. According to our liquefaction assessment, the loose and medium dense alluvium and the medium dense highly weathered sandstone below the water table identified in our CPT explorations are susceptible to seismic liquefaction with about 2.5 to 3 inches of total liquefaction-induced settlement. Golder proposes ground improvement below the new foundation to provide liquefaction mitigation as well as bearing capacity improvement. The new building foundation would consist of spread footings bearing on the improved ground conditions. We propose that the existing timber piles beneath the cinema building be allowed to remain in place below the new apartment building foundation; however, pile caps located at 1.5 to 4 feet below finished grade will be removed as needed. The existing piles would not be relied upon as structural foundation bearing members for the new foundation. Ground improvement elements consisting of rammed aggregate piers, grouted stone columns, or rigid intrusions would be added to provide an improved zone of soil capable of supporting the new foundation loads. Geologic critical areas such as severe erosion, steep slopes, landslides, aquifer recharge areas, abandoned coal mines, and liquefaction-induced lateral spreading were examined at the project site. The Site is not located in an abandoned coal mine hazard or aquifer recharge area and the level of risk from erosion, steep slopes, landslides and lateral spreading are judged to be low. March 2017 i 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx Table of Contents EXECUTIVE SUMMARY ........................................................................................................................ ES-1 1.0 PROJECT INFORMATION AND SITE DESCRIPTION ................................................................... 1 2.0 FIELD EXPLORATIONS, LABORATORY AND IN-SITU TESTING ................................................ 2 3.0 SUBSURFACE CONDITIONS ......................................................................................................... 3 3.1 Soil Conditions ............................................................................................................................. 3 3.2 Groundwater Conditions .............................................................................................................. 3 3.3 Bedrock Depth.............................................................................................................................. 4 4.0 CRITICAL AREAS ASSESSMENT .................................................................................................. 5 4.1 Severe Erosion ............................................................................................................................. 5 4.2 Steep Slopes ................................................................................................................................ 5 4.3 Landslides .................................................................................................................................... 5 4.4 Wellhead Protection Areas ........................................................................................................... 5 4.5 Abandoned Coal Mine .................................................................................................................. 6 4.6 Seismic Hazards .......................................................................................................................... 6 4.6.1 Surface Rupture ....................................................................................................................... 6 4.6.2 Liquefaction and Induced Settlement ...................................................................................... 6 4.6.3 Liquefaction-Induced Lateral Spreading .................................................................................. 7 4.6.4 Seismically Induced Landslides ............................................................................................... 7 5.0 ENGINEERING RECOMMENDATIONS ......................................................................................... 8 5.1 Foundation Options and Recommendations ................................................................................ 8 5.1.1 Pile Supported Foundation: Auger-Cast Piles ......................................................................... 8 5.1.2 Shallow Foundations with ground improvement ...................................................................... 9 5.2 Ground Improvement Options .................................................................................................... 11 5.3 Seismic Design........................................................................................................................... 12 5.3.1 Site Class ............................................................................................................................... 12 5.3.2 Ground Motion Parameters .................................................................................................... 13 5.4 Slab Subgrade............................................................................................................................ 14 5.4.1 Structural Fill Placement and Compaction ............................................................................. 14 6.0 CONSTRUCTION CONSIDERATIONS ......................................................................................... 16 6.1 Removal of Existing Pile Caps ................................................................................................... 16 6.2 Earthworks ................................................................................................................................. 16 6.2.1 Subgrade and Foundation Preparation .................................................................................. 16 6.2.2 Use of Onsite Excavated Soil ................................................................................................ 16 6.2.3 Use of Reclaimed Concrete Material (RCM) ......................................................................... 17 6.2.4 Structural Fill .......................................................................................................................... 17 6.2.4.1 Materials ............................................................................................................................. 17 6.2.4.2 Placement .......................................................................................................................... 18 March 2017 ii 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 6.2.4.3 Compaction ........................................................................................................................ 18 6.2.4.4 Subgrade Verification and Compaction Testing ................................................................ 19 6.2.5 Wet Weather Construction ..................................................................................................... 19 6.3 Temporary Slopes ...................................................................................................................... 19 6.4 Pavement Subgrade Preparation and Pavement Design Recommendations ........................... 20 6.5 Geotechnical Construction Monitoring ....................................................................................... 20 6.6 Use of Report ............................................................................................................................. 20 7.0 CLOSING ....................................................................................................................................... 21 8.0 REFERENCES ............................................................................................................................... 22 List of Tables (in text) Table 3-1 Bedrock Depth in the Past and Recent Explorations Table 5-1 Allowable Axial Compressive and Uplift Capacity Values for Auger-Cast Piles Table 5-2 LPILE Parameters for Auger-Cast Piles Table 5-3 Capillary Break Gradation Table 6-1 Compaction Criteria List of Figures Figure 1 Vicinity Map Figure 2 Exploration Locations List of Appendices Appendix A Timber Pile Foundation for the Existing Cinema Building: Plan and Details Appendix B 1987 Borehole Logs Appendix C Golder 2017 CPT Logs Appendix D Assessment of City of Renton Critical Areas Appendix E Liquefaction Assessment March 2017 1 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 1.0 PROJECT INFORMATION AND SITE DESCRIPTION This geotechnical report presents the results of Golder Associates Inc.’s (Golder’s) geotechnical investigation for the proposed re-development at Via 405 Apartment building at 25 South Grady Way in Renton, Washington (Site). The report was developed in general accordance with our proposal dated January 4, 2017 for the field investigation and geotechnical services. The Site consists of an existing cinema building situated on tax parcel # 7232000010 located just northeast of the intersection of Interstate 405 and Highway 167. The parcel is bordered by a small creek (Rolling Hills Creek) and Interstate 405 to the south and commercial property (parking lots and buildings) on the north, east, and west sides. The site topography is flat and lies at approximately 28 feet. The location of the Site is shown in Figure 1. The existing cinema building was constructed around 1988 and contains a wood timber pile supported structural slab foundation. The 8-inch diameter piles were driven to end bearing on bedrock at depths ranging from about 15 to 48 feet below ground surface. The foundation plan of the cinema building as well as the foundation detail drawings are shown in Figures A-1 and A-2 of Appendix A. As shown in Figure A-2, the pile caps are 1.5 to 4 feet embedded below the floor slab. The building is surrounded by asphalt paved parking and driveways. The proposed apartment building will be constructed on the footprint of the existing cinema which will be demolished. The apartment building footprint is slightly larger particularly on the east side. The building is roughly rectangular shaped with a bevel cut out of the northeast corner due to constraints from an overhead powerline easement. The building will contain a two level concrete parking podium with six levels of wood- frame residential units above. The residential units will wrap around a central courtyard. No below grade structures are planned. March 2017 2 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 2.0 FIELD EXPLORATIONS, LABORATORY AND IN-SITU TESTING Golder reviewed the previous geotechnical reports by GeoEngineers in 1987 and 1988. The previous geotechnical explorations were conducted for the construction of existing cinema building and consisted of drilling four boreholes. Boreholes B-1 to B-4 located on the north, east, and south sides of the Site were drilled on July, 3, 6, and 7, 1987 to bedrock at depths ranging from 13 to 48 feet below grade. Location of the boreholes are shown in Figure 2. The boreholes were advanced using a truck mounted, continuous- flight, hollow stem auger drill and split spoon sampler was driven into soil with a 300-pound hammer free- falling 30 inches to conduct Standard Penetration Testing (SPT) and obtain split spoon samples. GeoEngineers did moisture content and dry density testing on selected samples. Observations of groundwater were made during drilling and standpipe piezometers were installed in all explorations to monitor groundwater level following drilling as well. Boring logs and a description of drilling and sampling are provided in Appendix B. For the current development plan, Golder contracted InSitu Engineering to conduct four Cone Penetration Tests (CPTs) to supplement the 1987 boreholes. A CPT is a small diameter steel probe pushed down through the soil column. It collects data on soil properties at 10 centimeter (cm) intervals and is commonly used in loose soils to assist in liquefaction assessments and for ground improvement designs. The four CPT explorations, referred to as CPT-01 to -04, were completed on February 15, 2017 and advanced to the bedrock surface with variable depths ranging from 17.5 to 31 feet below grade. Locations of the Golder CPTs are shown in Figure 2 as well. CPT logs including the cone tip resistance, the friction ratio (i.e. ratio of cone side resistance to cone tip resistance), recorded pore pressure, the interpreted soil behavior, and equivalent SPT blow counts are provided in Appendix C. March 2017 3 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 3.0 SUBSURFACE CONDITIONS 3.1 Soil Conditions The general soil profile at the Site consists of fill of less than 7 feet, underlain by alluvial deposits and bedrock. The site soils are described further as follows: Fill – Fill was found in the 1987 boreholes and also observed in Golder 2017 CPTs with variable thickness of 2.5 to 7 feet. Fill soils generally consisted of medium dense to dense sand with trace of silt and gravel. Alluvial Deposits – Alluvium was found directly below the fill. Based on our CPT the alluvium consists of silt and organic silt with the variable thickness of 6 feet in CPT-01, 0.5 feet in CPT-02, 9 feet in CPT-03, and 12 feet in CPT-04. The silty layer is soft to firm in CPT-01 and CPT-04 on the south and north sides of the Site and stiff to very stiff in CPT-03 on the east side of the Site. (As it will be discussed in detail in the subsequent sections of the report, this layer is not liquefiable except for an interbedded 3-feet thick sandy layer observed in CPT-03.) The silt layer is overlaying a medium dense sand/silty sand layer with varying thickness of 5 feet in CPT-03 to 12 feet in CPT-01, -02, and -03. Except for CPT-03, interbedded silt layers have also been identified in the bottom 4 feet of this layer. As it will be discussed in the next sections, this layer is susceptible to seismic liquefaction. The alluvial deposit is underlain with varying thickness of highly weathered sandstone in the form of medium dense to very dense fine or fine to medium sand. The thickness is variable from 0.2 feet in CPT-04 to 7 feet in CPT-03. The medium dense sections in this layer is liquefiable. The CPT subsurface profile is reasonably consistent with the general subsurface profile inferred from the previous 1987 boreholes. Bedrock – Moderately hard sandstone was encountered at depths ranging from 13 to about 48 feet below grade, generally sloping down from southeast to northwest of the Site. The location of bedrock in our CPTs is generally consistent with the 1987 boreholes. The depth of bedrock encountered in explorations is shown in Table 3-1. 3.2 Groundwater Conditions Groundwater conditions were evaluated based on 1987 groundwater measurements in the four stand pipe piezometers installed in the boreholes. Groundwater levels were measured at 11, 8.5, 8.5 and 5.5 feet below ground surface in boreholes B-1, 2, 3, and 4, respectively, on July 14, 1987. Golder relied on the groundwater information from the 1987 investigation, since the CPT data was inconclusive to determine groundwater level. Please note that groundwater measurements were conducted in dry season and fluctuations in the ground water levels should be expected due to changes in precipitation, season, and other factors. March 2017 4 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 3.3 Bedrock Depth Table 3-1 summarizes the depth of bedrock observed in the 1987 and 2017 geotechnical explorations. The bedrock depths are also depicted for each exploration on the exploration plan in Figure 2. Table 3-1: Bedrock Depth in the Past and Recent Explorations Exploration Approximate Depth to Bedrock (ft below grade) 1987 Boreholes B-1 48 B-2 27 B-3 30 B-4 14 2017 Golder CPTs CPT-01 23.5 CPT-02 17.5 CPT-03 26 CPT-04 31 March 2017 5 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 4.0 CRITICAL AREAS ASSESSMENT Following the Renton Municipal Code Ordinance 5832, Section 4-3-050, the City of Renton requires the geotechnical critical areas to be assessed as part of new project geotechnical submittals. Critical areas include steep slopes, landslides, seismic liquefaction, severe erosion, flooding, aquifer recharge areas, and abandoned coal mine hazards. We understand that other consultants will be tasked with completing a flood study and an assessment of wetlands and streams. Following our proposal for geotechnical services, Golder’s scope included an assessment of severe erosion, steep slopes, landslides, aquifer recharge areas, abandoned coal mine, and seismic liquefaction hazard areas. 4.1 Severe Erosion Section 4-3-050, Ordinance 5832 of the Renton Municipal Code defines two levels of low (EL) and high (EH) erosion hazard. As shown in Figure D-1 in Appendix D, the Via 405 Site is located in the Low Erosion Hazard (EL) zone. No erosion mitigation is required for this designation. 4.2 Steep Slopes The closest steep slope to the Via 405 Site is the slope of the Rolling Hills Creek located on the south side of the Site with an average slope of about 50 percent and vertical rise of 7 feet. According to the Renton Municipal Code definitions, this slope is categorized as a “sensitive” steep slope (i.e. average slope ≥ 40 percent and a vertical rise less than 15 feet). The code does not specifically require any critical area buffer or structure setbacks for this slope designation, likely because of the limited slope height. However, it refers to the adopted building code requirements. International Building Code or IBC (2015) requires a clearance of the face of building footing to the slope more than the minimum of 40 feet and H/3, where H is the slope height. This requirement is also met since the proposed building at its nearest distance is 38 feet from the creek slope and the slope height is 8 feet. The location of the Site is also shown in the City of Renton map with respect to the steep slopes in Figure D-2 of Appendix D. 4.3 Landslides Section 4-3-050, Ordinance 5832 of the Renton Municipal Code defines four levels of low (LL), medium (LM), high (LH), and very high (LV) landslide hazard zones. As shown in Figure D-3 of Appendix D, the Site is located in the Low Landslide Hazard (LL) zone. No mitigation is required for landslide hazards for low hazard designation. 4.4 Wellhead Protection Areas Wellhead Protection Areas are the portion of an aquifer within the zone of capture and recharge area for a well or well field owned or operated by the City. Section 4-3-050, Ordinance 5832 of the Renton Municipal Code designates three Wellhead Protection Area Zones. The location of the Site is shown in the City of March 2017 6 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx Renton map with respect to aquifer protection zones in Figure D-4 of Appendix D. As shown in the map, the Site is not located in any of the Wellhead Protection Area Zones. 4.5 Abandoned Coal Mine Section 4-3-050, Ordinance 5832 of the Renton Municipal Code defines three zones of low (CL), medium (CM), and high (CH) hazard regarding the abandoned coal mines. According to the code, areas with no known mine workings and no predicted subsidence are defined as low coal mine hazard (CL) areas. As shown in Figure D-5 of Appendix D, the Site is located in the low coal mine hazards (CL) area and is not underlain by any known coal mines. 4.6 Seismic Hazards Renton Municipal Code defines two zones with low (SL), and high (SH) hazard regarding the seismic Hazards. Areas underlain by soft or loose, saturated soils with Site Classifications of E or F, as defined in the IBC (2015) are defined with High Seismic Hazard (SH) level. Considering the subsurface explorations and our liquefaction assessment, the Via 405 Site is in the High Seismic Hazard (SH) zone in case of no ground improvement. We evaluated the potential seismic-induced geotechnical hazards at the proposed site including surface rupture, liquefaction and induced settlement, lateral spreading, and seismically induced landslides. Our review of these hazards is based upon the past and recent subsurface explorations presented in this report, regional experience, and our knowledge of local seismicity. 4.6.1 Surface Rupture The Site is located approximately 9 kilometers (km) (about 5.8 miles) south of the southern trace of Seattle Fault zone, and approximately 35 km (about 22 miles) northwest of the Tacoma Fault zone (USGS 2008). The probability of surface rupture induced by these faults and impacting the Site is low in our opinion. 4.6.2 Liquefaction and Induced Settlement Strong ground shaking could trigger liquefaction: a rapid loss of soil shear strength and stiffness. Liquefaction can induce ground settlement, loss of bearing support, flow failure, lateral spreading and sand boils. Saturated very loose to medium dense, clean to moderately silty sands and low-plasticity silts below the groundwater are susceptible to liquefaction. Our liquefaction analyses were based on the current building code (IBC 2015), which specifies an earthquake return period of 2,475 years. We used the PGA of 0.573 g with moment magnitude of 7 in our liquefaction evaluation. Details on determination of Site Class and PGA will be presented in the subsequent sections of the report. The groundwater levels in the CPT explorations were also assumed based on the groundwater measurements in the adjacent 1987 boreholes: 8.5, 5.5, 7, and 10 feet below grade in CPT-01 to 04, respectively. March 2017 7 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx Golder performed the liquefaction assessment using LiquefyPro software (CivilTech 2011). LiquefyPro evaluates liquefaction potential based on the empirical liquefaction assessment approach (Youd and Idriss 2001) and calculates the estimated liquefaction-induced settlement in soil deposits. Profiles of liquefaction safety factor for our CPT explorations are presented in Figures E-1 to E-4. Our evaluations indicated that liquefaction is likely to occur in the loose to medium dense sandy alluvial deposit below groundwater level with in estimated settlement of 2.5 to 3.5 inches. Liquefaction profiles in Figures E-1 to E-4 also show the profiles of estimated settlement. 4.6.3 Liquefaction-Induced Lateral Spreading Liquefaction can induce lateral movement (lateral spreading) toward steep banks or slopes. The Via 405 Site is located close to a creek with a 7-foot high steep slope. However, the ground water level in the explorations and the top elevation of liquefiable layers are generally lower than the bottom of the creek, except for borehole B-4. In addition, the general grading of the entire Site dose not slope downward towards the creek. Therefore, in our opinion the lateral spreading hazard and its impact on the building structure is negligible. 4.6.4 Seismically Induced Landslides As indicted in Section 4.3 of the report, the Site is located in the Low Landslide Hazard (LL) zone. Therefore, the hazard associated with seismically induced landslide is low for this Site as well. March 2017 8 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 5.0 ENGINEERING RECOMMENDATIONS This section presents recommendations for the design of the proposed building. 5.1 Foundation Options and Recommendations After reviewing the existing project information and the available subsurface data, we developed a geotechnical project approach for foundation support for the new apartment building that would not require the removal of the existing timber piles. In our approach, the piles would not be relied upon as structural foundation bearing members for the new foundation. We propose two options for the new foundation: pile supported foundation and spread footings with ground improvement. 5.1.1 Pile Supported Foundation: Auger-Cast Piles An auger-cast (or continuous flight auger) pile is a mid-sized (typically 18 to 24 inches in diameter), drilled and grouted as replacement pile and typically reinforced. Auger-cast piles are a good alternative to driven piles due to the lower vibration and noise and more appropriate for urban areas. Auger-cast piles are installed by continuously drilling down to the pile embedment depth with a plug at the tip of the auger. When the pile reaches the designated embedment depth, the plug is removed and grout flows out of the auger under pressure as the auger is extracted from the hole. To increase the uplift pile structural capacity, a steel bar is usually inserted at the center of the pile and a steel cage is placed in the upper portion to provide increased lateral resistance. Auger-cast piles should extend at least 10 feet into the bedrock to provide sufficient lateral resistance during seismic event. Table 5-1 summarizes our recommendations on the allowable axial compressive and uplift capacity values for 18- and 24-inch diameter auger-cast piles. These recommendations are based on the minimum embedment of 10 feet in the bedrock. Table 5-2 also summarizes the LPILE (EnSoft 2016) parameters to evaluate the lateral resistance of auger-cast piles. The ground water level as well as thickness of fill and alluvium is variable. Table 3-1 and Section 3.2 of the report provides the information regarding the depth of the bedrock (i.e. thickness of fill and alluvium) and groundwater level in the site explorations respectively. All this information is also summarized in Figure 2 as well. Auger-cast pile foundations mitigate the excessive liquefaction induced total and differential settlement and provide sufficient lateral resistance for the foundation during shaking. Its continuous installation method also reduces the issues regarding drill hole stability in caving soils and improves the work speed. These advantages make auger-cast piles a viable option for the Site. March 2017 9 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx Table 5-1: Allowable Axial Compressive and Uplift Capacity Values for Auger-Cast Piles Pile diameter (in) Compressive (kips) Uplift (kips) 18 200 90 24 300 120 Table 5-3: LPILE Parameters for Auger-Cast Piles Geological Unit Total Unit Weight Effective Unit Weight Soil Type for LPILE Friction Angle (φ') Undrained Shear Strength, (Su) Soil subgrade modulus (k) Strain at 50% Max. Stress, ε50 Static Post- Seismic Static Post- Seismic ----- pcf pcf ----- Degree psf pci ----- Fill and Alluvium 120 57.6 Sand (Reese) 30 16 ------- 20 10 ------- Bedrock 140 77.6 Stiff Clay w/o Free Water (Reese) ------- ------- 12000 ------- ------- 0.004 5.1.2 Shallow Foundations with ground improvement Golder’s recommendation for foundations also includes the application of spread footings with ground improvement elements installed to support shallow foundations of the new building and to meet bearing capacity requirements as well as static and/or seismic induced settlement tolerances. Our recommended approach would be to keep the existing piles (remove pile caps as needed) beneath the new apartment building foundation. Due to the presence of liquefiable loose to medium dense sand and compressible silt/organic silt deposits, ground improvement elements should be added to provide an improved zone of soil capable of supporting the new foundation loads under static and seismic loading. The proposed soil improvement should also limit the total and differential static settlement. This option should be more economical than the auger-cast piles option. The actual design of the ground improvement – including developing the design geotechnical parameters - should be completed by the ground improvement contractor. The design by the ground improvement should be reviewed by Golder and the structural engineer. Presented below are preliminary design criteria that can be used for initial design. Design isolated footings using an allowable bearing pressure of 6 kips per square foot (ksf). March 2017 10 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx Design continuous footings using an allowable bearing pressure of 4 ksf. The above bearing pressures should be considered gross bearing values. The maximum allowable bearing pressures assume vertical loading conditions. The values presented may be increased by one-third for short-term wind and seismic loading. Continuous and isolated footings should be embedded at least 18 and 36 inches respectively below the adjacent finished grade. The Minimum Footing Widths: Perimeter Footings ................................................................................................... 4 feet Interior Isolated Footings .......................................................................................... 6 feet Static settlement (due to building loads): Total Settlement ....................................................................................... less than 1 inch Differential Settlement ........................................................................... less than 1/2 inch Seismic or liquefaction-induced settlement (due to building loads): Total Settlement ....................................................................................... less than 2 inch Differential Settlement .............................................................................. less than 1 inch Building foundations must resist lateral loads due to earth pressures, wind, and seismic events. For the initial design purposes, these loads can be assumed to be resisted simultaneously by: BASE FRICTION: For the ground improvement methods presented subsequently, a layer of gravel is typically placed beneath the shallow foundations. An allowable value of 0.35 can be assumed for base friction between the gravel layer and spread footings. This value includes a factor of safety of 1.5. The allowable base friction value may be increased by one-third for the seismic loading. PASSIVE RESISTANCE ON SIDES OF SHALLOW FOOTINGS: We understand that the pile caps of the existing timber piles at the depth of 1.5 to 4 feet below floor slab should be removed. Therefore, we anticipate using the laid-back excavations to a maximum depth of 4 to 5 feet to construct the shallow foundations. Structural fill should be placed between the sides of foundation and the sloped excavations and compacted according to our recommendations in Section 5.4.1. For initial design purposes, we recommend that the allowable passive pressure be based on a fluid with a density of 400 pounds per cubic foot (pcf) (including a factor of safety of 1.5) for footings embedded in the structural fill. The allowable passive value is based on the assumption that the footing subgrade is above the regional groundwater table. The allowable passive resistance can be increased by one- third for seismic loading. Since some disturbance is likely to occur during construction, we recommend the upper 1 foot of passive resistance be neglected. General discussions are provided below for ground improvement options. During the final design phase of the project, foundation support options should be reviewed with the project team to determine the preferred foundation support alternative. March 2017 11 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 5.2 Ground Improvement Options Ground improvement is designed to improve the strength and deformation engineering properties of the soil. Ground improvement can mitigate the adverse impacts of liquefaction through one or combination of three mechanisms: 1) densifying the soil mass, 2) dissipating excess pore pressures, and 3) reinforcing the soil mass. The appropriate method of ground improvement is related to the nature of the soil to be improved (e.g. coarse grained, fine grained, highly organic, or a mixture of these different types of soil), the loads and performance requirements of the structure slabs and foundations, the time and cost for improvement, and other factors. Ground improvement is typically designed and constructed by a specialty contractor familiar with ground improvement and contracted via a design-build performance specification. The design-build approach is generally preferable since the specialty contractor can customize the design of the ground improvement system to optimize the use of available equipment with site soils and project performance requirements. We recommend the specialty contractor be required to provide a performance-based design, sealed by an experienced professional engineer licensed in the State of Washington, which meets the support and settlement performance criteria provided in this report and in the final project plans and specifications. We recommend that the owner, the project structural engineer, and Golder jointly review and approve the ground improvement design specification and the design. Golder contacted two recognized soil improvement contractors for a preliminary evaluation of the Site: Hayward-Baker Inc. (HBI) and Geopier Foundation Co. NW (GFC). Ground improvement contractors proposed three methods of ground improvement as most cost effective and appropriate for the Site. These methods are briefly discussed below: Rigid inclusions (RIs) consist of unreinforced lean concrete columns installed to transfer loads through weak soils to the bearing soil below the building foundation elements. Rigid inclusions mainly “densify” and “reinforce” the compressible soils. Rigid inclusions are placed in a grid pattern to distribute the foundation loads and provide a “block” of a composite soil and lean concrete material that will reduce the potential for differential settlement. Advantages with the use of rigid inclusions include: 1) lean concrete columns are more economical than auger-cast piles (shorter length, no reinforcement, and allows for the use of conventional spread footings/slabs-on-grade), 2) there is minimal disturbance and vibration of adjacent structures during installation, and 3) the technique produces minimal soil waste to be disposed. Rigid inclusions are constructed using similar techniques for installing auger-cast piles. Typically a bottom-feed mandrel with a top-mounted vibrator is advanced through the weak strata to the underlying bearing stratum. Lean concrete is then pumped into the hole through the auger tip as the auger is extracted out of the hole. March 2017 12 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx In seismically active areas a single steel bar can be installed after the completion of concrete placement. The steel bar prevents the concrete from crumbling during seismic shaking. The layout/design of the rigid inclusions will be completed once the building design has been finalized. Here are some preliminary design information for the preliminary design and pricing purposes: - 18- to 24-inch-diameter columns - load carrying capacities on the order of 100 to 200 kips per RI element - 5- to 6-foot rigid inclusion spacing for spread and strip foundations - No columns necessary below the slab-on-grade - Rigid inclusions extending from the bottom of foundation elevation to the bedrock, with a 6-inch gravel break layer between the footing base and top of the rigid inclusion Rammed Aggregate Piers (RAPs, also known GeoPiers) consists of stiff aggregate piers that reinforce fine grained soils and densify coarse grained deposits. The piers are often constructed using a bottom feed horizontally oscillating vibrator which is advanced to a predetermined depth under its own weight and vibrations. The downhole vibrator is lowered vertically to the designed tip of the pier typically with a standard crane or large excavator. Aggregate (new crushed stone or recycled concrete) is then injected into the hole and compacted in lifts by repeated penetrations with the vibrator. The vibratory energy from the vibrator densifies the aggregate and any surrounding granular soil. The vibrator is raised and lowered several times to construct a compacted aggregate element of the diameter required by the design. Due to the presence of soft silt/organic silt layer, the pier should also be grouted to avoid budging and subsequent settlement induced by loss of aggregates in the soft deposit. Diameters of 24 to 48 inches are common for RAPs. A net allowable bearing pressure of 6 ksf as well as total and differential settlements of 1 and 0.5 inch for shallow foundations at the project site could be achieved through this method. The RAP design will be highly dependent on the allowable differential settlement performance criteria provided by the design team. Grouted stone column combines the benefits of rigid inclusion and aggregate pier system s. Similar to rigid inclusions, vibro-concrete columns transfer loads through weak strata to a bearing underlying layer , using a combination of low strength concrete and stone aggregate backfill. Similar to aggregate piers, a bottom-feed down-hole vibratory probe is advanced through the weak strata to the underlying firm stratum and granular bearing soils are densified by the vibrator. Cement and water are then mixed with stone aggregate and the mixture is discharged from the base of the bottom feed tremie tube. The vibrator is raised and lowered several times to construct a cemented stone column with the required design diameter. Diameters of 24 to 48 inches are common and load carrying capacities on the order of 100 kips are commonplace; however, significantly higher capacities are also possible. 5.3 Seismic Design The seismic design recommendations are presented below. 5.3.1 Site Class We understand that the seismic design of the proposed development will be performed in accordance with the 2015 International Building Code (IBC). IBC (2015) indicates that the Site Class shall be classified in March 2017 13 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx accordance with Chapter 20 of American Society of Civil Engineers (ASCE) 7-10. Based on ASCE 7-10, Section 20.3, any site with soils vulnerable to potential failure or collapse under seismic liquefaction is considered Site Class F, which is the case for the Via 405 Site. ASCE 7-10 and IBC (2015) do not provide site effect factors for site class F and require site response analysis to obtain seismic design parameters. However, according to an exception in ASCE 7-10, for structures with fundamental periods equal or less than 0.5 second, site response analysis is not required to determine spectral accelerations for liquefiable deposits. Rather, a site class is permitted to be determined according to Section 20.3 of ASCE 7-10 based on the soil properties (shear wave velocity, SPT blow counts, and/or undrained shear strength) of the top 100 feet and the corresponding site factors to be used to adjust the Site Class B spectral accelerations. Given the number of stories and type of the building (i.e. eight story: two level concrete parking podium with six levels of wood-frame structure), we expect the structure fundamental period to be higher than 0.5 second. However, this is the structural engineer’s responsibility to confirm the structure fundamental period. In case of using auger-cast piles, the “controlling” earthquake motion would be at the interface of the liquefiable/soft soils with bedrock – corresponding to Site Class B or C. In other words, the effect of liquefaction/soft soils should be negligible on the seismic design of the proposed building. In case of using ground improvement, it is our professional opinion that the reduction of liquefaction potential and the reinforcement effect due to installation of ground improvement would alter the site class from Site Class F to roughly Site Class D. Considering the above, we recommend the use of Site Class D – which is more conservative compared to Site Classes B and C. Our evaluations for the site class was based on the soil properties using both methods 2 and 3 in section 20.3.3 of ASCE 7-10. 5.3.2 Ground Motion Parameters We obtained the seismic parameters using the United States Geologic Survey (USGS) application (https://earthquake.usgs.gov/designmaps/us/application.php ), which provides values in accordance with IBC (2015). All the IBC (2015) seismic values are developed based on USGS 2008 national hazard maps. The basis of design for this code is two-thirds of the hazard associated with an earthquake with 2 percent probability of exceedance in a 50-year time period, which corresponds to an average return period of 2,475 years. The ground motion parameters for Site Class B and the site location at Latitude 47.469 and Longitude -122.214 are presented in below: Maximum Considered Earthquake Spectral Acceleration at Short Periods (0.2-Second): Ss = 1.423 g Maximum Considered Earthquake Spectral Acceleration at 1-Second Period: S1 = 0.535 g March 2017 14 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx Peak Ground Acceleration for Site Class B: PGA = 0.573 g The above values should be adjusted for Site Class D as discussed above. 5.4 Slab Subgrade Conventional slab-on-grade floors can be supported on a subgrade of the native bearing soils or on structural fill placed and compacted as noted in the Earthworks section of this report (Section 6.2.4). Slab- on-grade floors should not be founded on loose soils, or uncompacted fills. The slabs should be underlain by a capillary break material consisting of at least 4 inches of clean, free draining sand and gravel or crushed rock containing less than 3 percent fines passing the No. 200 sieve (based on the minus No. 4 sieve fraction); meeting the specification in Table 5-3. Table 5-3: Capillary Break Gradation Sieve Size or diameter (inches) % Passing 1 100% passing No. 4 0 - 20% No. 200 0 - 3% Vapor transmission through floor slabs is an important consideration in the performance of floor coverings and controlling moisture in structures. Floor slab vapor transmission can be reduced through the use of suitable vapor retarders, such as plastic sheeting placed between the capillary break and the floor slab, and/or specially formulated concrete mixes. Framed floors should also include vapor protection over any areas of bare soils, and adequate crawl space ventilation and drainage should be provided. The identification of alternatives to prevent vapor transmission is outside of our expertise. A qualified architect or building envelope consultant can make recommendations for reducing vapor transmission through the slab, based on the building use and flooring specifications. 5.4.1 Structural Fill Placement and Compaction Where needed, structural fill should be a granular soil (with less than 5 percent passing the No. 200 sieve) that when placed and compacted will meet the required compaction specifications. Structural fill should be placed in 8-inch (or less) loose lifts and compacted to at least 95 percent of maximum ASTM D1557 dry density below all footings and within 3 feet of final grade in pavement areas. In addition, structural backfill placed around footings should also be compacted to at least 95 percent of ASTM D1557. We recommend a minimum dry density of 90 percent ASTM D1557 beneath floor slabs and other structural components, such as utility service trenches, not underlying pavements or footings. Structural fill behind backfilled walls should be compacted to 90 percent of ASTM D1557, provided the backfill is not supporting buildings and is not within 3 feet of final grade in pavement areas. If density tests indicate that compaction is not being March 2017 15 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx achieved due to moisture content, the fill should be scarified, moisture-conditioned to near optimum moisture content, re-compacted, and re-tested, or removed and replaced. March 2017 16 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 6.0 CONSTRUCTION CONSIDERATIONS Geotechnical-related site construction would consist of demolition of the Cinema building, excavation and removal of the existing timber pile caps, placing crushed rock or gravel-working mat as a platform for construction equipment, construction of foundation support (i.e. auger-cast pile or ground improvement), preparation of the building foundation and slab subgrades, backfilling foundation walls, and installing new utilities. This section discusses selected elements of these construction issues. 6.1 Removal of Existing Pile Caps As shown in the existing foundation plan and details (Figures A-1 and A-2 of Appendix A), the bottom of the existing pile caps supporting the interior and perimeter columns and walls are generally 4 and 1.5 to 2 feet below the finished grade, respectively. The pile cap thickness is 1.5 feet in general. As mentioned before, the plan is to remove the pile caps as needed. Therefore, excavation to 4 to 5 feet below finished grade will be required to access the pile caps. 6.2 Earthworks 6.2.1 Subgrade and Foundation Preparation Following the excavation of the fill material to expose and remove pile cap, the foundation subgrade will likely encounter soft to stiff silt/organic silt based on the proposed existing finished floor elevation of the building and the available subsurface information. After completing the construction of foundation support, structural fill or recycled concrete should also be placed and compacted under the foundations, floor slabs, and pavements. Uncontrolled fill or any other loose, soft, disturbed, compromised material or water should be removed from beneath foundations prior to placement of reinforcing bars and concrete. Uncontrolled fill may be left in place beneath floor slabs and pavements if it can be compacted to a firm and unyielding condition as noted in Section 6.2.4. Exposed subgrades for footings, floor slabs, pavements, and other structures should be compacted with a vibratory roller to a firm, unyielding state. Any localized zones of loose granular soils observed within a subgrade should be compacted to a density appropriate for planned development. Any organic, soft, or pumping soils observed within a subgrade should be over-excavated and replaced with a suitable structural fill material. Unsuitable excavated materials should not be mixed with materials to be used as structural fill. 6.2.2 Use of Onsite Excavated Soil The native alluvium soil is not considered suitable to use as structural fill. However, the excavated fill below the slab on grade of the existing cinema building may be appropriate to use as structural fill provided it can be placed and compacted near the optimum moisture content and in accordance with the compaction March 2017 17 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx requirements presented in Section 6.4.2.3 of this report. If density tests indicate that compaction is not being achieved due to moisture content, the reused material should be scarified and moisture-conditioned to near optimum moisture content, re-compacted, and re-tested, or removed and replaced. 6.2.3 Use of Reclaimed Concrete Material (RCM) Reclaimed concrete material (RCM) aggregates are considered by many specifying agencies to be conventional aggregate. RCM should be processed to satisfy the conventional soil and aggregate physical requirements for fill material. Prior to its use, any reinforcing steel must be removed. RCM should be crushed and screened to satisfy AASHTO M145, and ASTM D2940 gradation requirements for fill aggregates. The processed RCM may contain some reclaimed asphalt pavement (RAP), when the RCM is derived from composite pavements. It is recommended that the RAP content in the RCM be limited to 20 percent to prevent a reduction in bearing strength due to the presence of RAP. Due to their high angularity, additional compaction effort may be required to compact RCM to its maximum density. The processor may be required to satisfy moisture content criteria according to AASHTO T99, in order to achieve proper compactibility. This usually requires the addition of water during placement and compaction. The same quality control test procedures (e.g. in-situ density testing using Rubber-Balloon, Sand Cone, and Nuclear Methods) applied for conventional aggregate are also appropriate for fill applications when using RCM. The high alkalinity of RCM (pH greater than 11) can result in corrosion to aluminum or galvanized steel pipes in direct contact with RCM and in the presence of moisture. To avoid corrosion problems, RCM should not be placed in contact with aluminum or galvanized steel pipes. The issue of high alkalinity of RCM may also impact the water quality of the water which is exposed to RCM. During the earthwork construction, the affected water which has been exposed to RCM should be collected and treated to meet the standard requirements for pH before being discharged. Caution is also warranted in locations subject to wet conditions, as tufa-like precipitates (CaCO3) associated with the leachate from RCM may develop upon exposure to the atmosphere. 6.2.4 Structural Fill The term "structural fill" refers to any materials placed under foundations, floor slabs, pavements, backfill for walls, and utility trench backfill. Golder’s conclusions and recommendations concerning structural fill are presented in the following sections. 6.2.4.1 Materials Structural fill should be free of organic and inorganic debris, near the optimum moisture content, and capable of being compacted to the required specifications for application. Soils used for structural fill generally should not contain any organic matter or debris or any individual particles greater than 6 inches March 2017 18 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx in diameter depending on use. Typical structural fill materials include clean sand and gravel; well-graded mixtures of sand and gravel (commonly called "gravel borrow" or "pit-run"); mixtures of silt, sand, and gravel; crushed rock; quarry spalls; and controlled-density fill (CDF). If onsite soils do not meet the above criteria, or cannot be reworked to a suitable condition, we recommend using imported granular fill consisting of imported, clean, well-graded sand and gravel, such as “Gravel Borrow” per Washington State Department of Transportation (WSDOT): 9-03.14(1) (WSDOT 2014). Other fill materials may be used with approval of geotechnical engineer. If imported material is needed for filling during wet weather, the project specifications should include provisions for using imported, clean, well-graded sand and gravel, such as “Gravel Borrow” per WSDOT: 9-03.14, except that the percent passing the US No. 200 sieve should be no greater than 5 percent. 6.2.4.2 Placement Fill should be placed in horizontal lifts not exceeding 8 inches in loose thickness, and each lift should be thoroughly compacted with a mechanical compactor. Any structural fill placed beneath footings should extend laterally outside of the footing base at a 1H:1V (Horizontal to Vertical) slope projected down and away from the bottom footing edge. In areas of thick structural fill (i.e. thickness > about 3 feet) this requirement may be relaxed with geotechnical engineer permission. 6.2.4.3 Compaction Using the Modified Proctor test (ASTM D1557) as a standard, we recommend that structural fill used for onsite applications be compacted to minimum densities presented in Table 6-1. Table 6-1: Compaction Criteria Fill Application % Minimum Compaction Building pad 95 Footing subgrade or bearing pad 95 Slab-on-grade floor subgrade and subbase 95 Retaining wall footing subgrade 95 Concrete slab subgrades 95 Asphalt pavement base and subbase 95 Asphalt pavement subgrade 95 Retaining wall backfill 90 Footing and stemwall backfill 90 Landscaped Areas 85 March 2017 19 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 6.2.4.4 Subgrade Verification and Compaction Testing All structural fill should be placed over firm, unyielding subgrades prepared in accordance with the recommendations in this report. The condition of all subgrades should be verified by the geotechnical engineer before filling or construction begins. Fill soil compaction should be verified by means of in-place density tests performed per ASTM D6938 during fill placement as earthwork progresses. Pavement and foundation subgrades should be maintained in a well compacted state and protected from degradation prior to paving or placing concrete. Protection measures may include restricted traffic, perimeter drain ditches, or placement of a protective gravel layer on the subgrade. Disturbed or wet areas should be removed and replaced by suitably compacted structural fill. 6.2.5 Wet Weather Construction Although feasible, earthwork construction during wet weather or rainy season will significantly increase costs associated with offsite disposal of unsuitable excavated soils, amount of dewatering needed to reach foundation elevations, increased control of surface water, and increased subgrade disturbance and need for soil admixtures, geotextiles, or rock working mats. For fill placement during wet-weather site work, we recommend using soils that have fines content of 5 percent or less (by weight). 6.3 Temporary Slopes Safe temporary slopes are the responsibility of the contractor and should comply with all applicable Occupational Safety and Health Administration (OSHA) and Washington Industrial Safety and Health Act (WISHA) standards. Temporary, stable cut slopes less than 8 feet in height can generally be constructed using the following recommendations: Uncontrolled Fill and Native Alluvium – 1.5H:1V As previously discussed, groundwater will may be encountered during construction. If temporary cuts encounter groundwater seepage, they should be sloped at 2H:1V or flatter (as recommended by the geotechnical engineer at the time of construction) to prevent significant caving or sloughing. Temporary cuts in the looser granular materials are expected to have some raveling at the cut face. Temporary cut slopes in granular soils may need to be laid back flatter than 1.5H:1V if a change in material type or debris is encountered. In the event that groundwater seepage is encountered during excavation, the contractor must install temporary drainage measures to protect the cut face and prevent degradation of the excavation area until permanent drainage measures can be constructed. March 2017 20 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 6.4 Pavement Subgrade Preparation and Pavement Design Recommendations The existing plans do not show the need for pavement. However, in the event some of the existing pavement is damaged and needs to be replaced, we recommend that the new pavement section match the adjacent paved sections. Golder can also provide recommendations for new pavement if needed based on the traffic load demand of the section. Section 6.2.4.3 of this report includes the general preliminary recommendations for compaction requirements of the asphalt pavement base, subbase, and subgrade. 6.5 Geotechnical Construction Monitoring We recommend that a qualified geotechnical-engineering firm is onsite during critical aspects of the project. This would include: foundation subgrade preparation. The geotechnical engineer of record will perform the special inspection. 6.6 Use of Report This report has been prepared exclusively for the use of RVA Cinema LLC, Parkway Capital, Inc. and their consultants for the project site. We encourage review of this report by bidders and/or contractors as it relates to factual data only. The conclusions and recommendations presented in this report are based on the explorations and observations completed for this study, conversations regarding the existing site conditions, and our understanding of the planned development. The conclusions are not intended nor should they be construed to represent a warranty regarding the development, but they are included to assist in the planning and design process. Judgment has been applied in interpreting and presenting the results. Variations in subsurface conditions outside the exploration locations are common in geologic condition, such as those encountered at the Site. Actual conditions encountered during construction might be different from those observed in the explorations. When the site project plans are finalized, we recommend that Golder be given the opportunity to review the plans and specifications to verify that they are in accordance with the conditions described in this report. The explorations were advanced in general accordance with locally accepted geotechnical engineering practice; subject to the time limits, and financial and physical constraints applicable to the services for this project, to provide information for the areas explored. There are possible variations in the subsurface conditions between the borehole locations and variations over time. The professional services retained for this project include only the geotechnical aspects of the subsurface conditions at the Site. The presence or implication(s) of possible surface and/or subsurface contamination resulting from previous site activities and/or resulting from the introduction of materials from off-site sources are outside the scope of services for this report and have not been investigated or addressed. March 2017 21 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 7.0 CLOSING We trust that this report meets your needs. If you have questions or comments, please contact us at (425) 883-0777. We appreciate the opportunity to provide our services for this project. GOLDER ASSOCIATES INC. Hamidreza Nouri, PhD, PE James G. Johnson, LG, LEG Project Geotechnical Engineer Principal HN/JGJ/ks 3/20/17 March 2017 22 1771669.100 1771669-via 405 geotechnical report-032017-rev0.docx 8.0 REFERENCES American Society of Civil Engineers (ASCE). 7-10. 2010. CivilTech Software. LiquefyPro. 2011. Version 5.8a. American Society for Testing and Materials (ASTM). 2010. Conshohocken PA: ASTM. D1557 Laboratory Compaction Characteristics of Soil Using Modified Effort D2940-92, Graded Aggregate Material for Bases and Subbases for Highways or Airports D6938 In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth) (2010) Ensoft Inc. Software. LPile. 2016. Version 2016.9.08. GeoEngineers. 1987. Geotechnical Engineering Services Report, Reconstruction of Renton Village Cinema, Renton, Washington. July 21, 1987. GeoEngineers. 1988. Addendum Report, Additional Geotechnical Consultation, Renton Village Cinema Reconstruction, Renton, Washington. May 24, 1988. International Building Code (IBC) 2015. International Code Council, Inc. USGS. 2008. The 2008 Probabilistic Seismic Hazard Analysis (PSHA) Interactive Deaggregations Website. https://geohazards.usgs.gov/deaggint/2008/, (accessed January, 2013). Washington State Department of Transportation. (WSDOT). 2014. Standard Specifications for Road, Bridge, and Municipal Construction. Publication Number: M 41-10. Youd, T.L. and Idriss, I.M. 2001. Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils, ASCE, Journal of Geotechnical Engineering, Vol. 127, No.4, pp. 297-324. FIGURES CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev. G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_002.indd PARKWAY CAPITAL FIGUREPHASE VICINITY MAP VIA 405 APTS 100 11771669 REDMOND 2017-03-17 PROJECT LOCATION CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_013.inddPARKWAY CAPITAL FIGUREPHASE EXPLORATION LOCATIONS VIA 405 APTS 100 21771669 REDMOND 2017-03-17 APPENDIX A TIMBER PILE FOUNDATION FOR THE EXISTING CINEMA BUILDING: PLAN AND DETAILS CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_011.inddPARKWAY CAPITAL FIGUREPHASE TIMBER PILE FOUNDATION PLAN OF EXISTING CINEMA BUILDING VIA 405 APTS 100 A-11771669 REDMOND 2017-03-17 CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_012.inddPARKWAY CAPITAL FIGUREPHASE DETAILS OF TIMBER PILE FOUNDATIONS OF EXISTING CINEMA BUILDING VIA 405 APTS 100 A-21771669 REDMOND 2017-03-17 APPENDIX B 1987 BOREHOLE LOGS APPENDIX C GOLDER 2017 CPT LOGS CPT-01 CPT CONTRACTOR: In Situ Engineering CUSTOMER: Golder Inc LOCATION: Renton JOB NUMBER: 1771669 OPERATOR: Mayfield CONE ID: DDG1369 TEST DATE: 2/15/2017 12:27:10 PM PREDRILL: Punched 1' with blank CPT BACKFILL: #8 Bentonite SURFACE PATCH: Concrete COMMENT: Depth (ft) Tip Resistance (Qt) (TSF) 0 5000 5 10 15 20 25 30 35 Friction Ratio (Fs/Qt) (PERCENT) 0 20 Pore Pressure (U2) (PSI) -15 20 Soil Behavior Type (UNITLESS) 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *SBT/SPT CORRELATION: UBC-1983 0 12 SPT Correlation (UNITLESS) 0 70 CPT-02 CPT CONTRACTOR: In Situ Engineering CUSTOMER: Golder Inc LOCATION: Renton JOB NUMBER: 1771669 OPERATOR: Mayfield CONE ID: DDG1369 TEST DATE: 2/15/2017 1:13:28 PM PREDRILL: Punched 1' with blank CPT BACKFILL: #8 Bentonite SURFACE PATCH: Concrete COMMENT: Depth (ft) Tip Resistance (Qt) (TSF) 0 5000 5 10 15 20 25 30 35 Friction Ratio (Fs/Qt) (PERCENT) 0 20 Pore Pressure (U2) (PSI) -15 20 Soil Behavior Type (UNITLESS) 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *SBT/SPT CORRELATION: UBC-1983 0 12 SPT Correlation (UNITLESS) 0 70 CPT-03 CPT CONTRACTOR: In Situ Engineering CUSTOMER: Golder Inc LOCATION: Renton JOB NUMBER: 1771669 OPERATOR: Mayfield CONE ID: DDG1369 TEST DATE: 2/15/2017 11:33:09 AM PREDRILL: Punched 1' with blank CPT BACKFILL: #8 Bentonite SURFACE PATCH: Concrete COMMENT: Depth (ft) Tip Resistance (Qt) (TSF) 0 5000 5 10 15 20 25 30 35 Friction Ratio (Fs/Qt) (PERCENT) 0 20 Pore Pressure (U2) (PSI) -15 20 Soil Behavior Type (UNITLESS) 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *SBT/SPT CORRELATION: UBC-1983 0 12 SPT Correlation (UNITLESS) 0 70 CPT-04a CPT CONTRACTOR: In Situ Engineering CUSTOMER: Golder Inc LOCATION: Renton JOB NUMBER: 1771669 OPERATOR: Mayfield CONE ID: DDG1369 TEST DATE: 2/15/2017 10:38:15 AM PREDRILL: Punched 1' with blank CPT BACKFILL: #8 Bentonite SURFACE PATCH: Concrete COMMENT: Depth (ft) Tip Resistance (Qt) (TSF) 0 5000 5 10 15 20 25 30 35 Friction Ratio (Fs/Qt) (PERCENT) 0 20 Pore Pressure (U2) (PSI) -15 20 Soil Behavior Type (UNITLESS) 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *SBT/SPT CORRELATION: UBC-1983 0 12 SPT Correlation (UNITLESS) 0 70 APPENDIX D ASSESSMENT OF CITY OF RENTON CRITICAL AREAS CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.FIGUREPHASE G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_001.inddMAP OF CITY OF RENTON CRITICAL AREAS: SEVER EROSION PARKWAY CAPITAL VIA 405 APTS 100 D-11771669 REDMOND 2017-03-17 CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_003.inddFIGUREPHASE MAP OF CITY OF RENTON CRITICAL AREAS: STEEP SLOPES PARKWAY CAPITAL VIA 405 APTS 100 D-21771669 REDMOND 2017-03-17 CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_004.inddFIGUREPHASE MAP OF CITY OF RENTON CRITICAL AREAS: LANDSLIDES PARKWAY CAPITAL VIA 405 APTS 100 D-31771669 REDMOND 2017-03-17 CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_005.inddFIGUREPHASE MAP OF CITY OF RENTON CRITICAL AREAS: WELLHEAD PROTECTION AREAS PARKWAY CAPITAL VIA 405 APTS 100 D-41771669 REDMOND 2017-03-17 CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_006.inddFIGUREPHASE MAP OF CITY OF RENTON CRITICAL AREAS: ABANDONED COAL MINE PARKWAY CAPITAL VIA 405 APTS 100 D-51771669 REDMOND 2017-03-17 APPENDIX E LIQUEFACTION ASSESSMENT CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_007.inddLiquefyPro CivilTech Software USA www.civiltech.comLIQUEFACTION ANALYSIS Via 405 Project Liquefaction Assessment: PGA=0.573; M=7 Plate A-1 Hole No.=CPT-01 Water Depth=8.5 ft Surface Elev.=28 Magnitude=7 Acceleration=0.573g (ft)0 5 10 15 20 25 30 35 17.3 1.45 120 NoLq17.3 1.45 120 29.6517.3 2.27 120 31.9617.3 1.39 120 33.6817.3 1.91 120 31.46185.6 2.48 135 2.42305.2 3.48 135 0.79274.5 3.23 135 1.13231.9 3.41 135 2.67203.4 3.1 135 3.24188.6 1.82 135 1.51166.2 1.41 135 1.33150.4 1.22 135 1.56135.2 1.02 135 1.78115.8 0.88 135 2.49106.7 0.89 135 3.4196.5 0.88 129 4.5572.6 0.77 132 6.9362.4 0.59 129 7.5453.8 0.61 127 9.9942.7 0.64 130 14.08340.61 125 18.0832.1 0.37 128 15.05460.33 127 9.1555.3 0.34 128 7.2449.4 0.49 130 10.7631.9 0.58 130 19.8722.3 0.57 130 28.1121.7 0.54 130 29.2321.9 0.58 130 30.0420.5 0.44 128 29.2415.9 0.39 124 NoLq11.9 0.31 124 NoLq10.1 0.31 114 NoLq6.1 0.27 116 NoLq6.9 0.21 119 NoLq5.9 0.11 109 NoLq4.1 0.1 109 NoLq3.9 0.11 109 NoLq3.9 0.12 109 NoLq3.9 0.11 106 NoLq3.4 0.17 120 NoLq9.9 0.22 120 NoLq7.6 0.2 108 NoLq3.9 0.14 108 NoLq4.2 0.14 112 NoLq6.4 0.19 110 NoLq5.4 0.19 112 NoLq6.6 0.18 120 NoLq7.6 0.2 112 NoLq6.2 0.18 121 NoLq9.6 0.21 125 NoLq34.9 0.35 125 NoLq22.1 0.38 129 NoLq16.4 0.58 120 NoLq21.4 0.98 120 NoLq201.25 120 NoLq19.3 1.36 120 NoLq23.2 1.09 130 NoLq33.9 0.63 125 NoLq40.8 0.31 125 14.6540.5 0.3 124 14.2535.1 0.21 124 14.2934.9 0.12 123 12.0032.9 0.12 124 12.8435.3 0.29 126 16.4044.9 0.38 125 14.1949.5 0.26 125 10.51530.14 125 7.0751.4 0.11 124 6.8146.7 0.12 123 8.1243.4 0.14 123 9.5742.6 0.14 123 9.9543.1 0.17 124 10.5845.7 0.2 124 10.5250.5 0.21 125 9.4855.3 0.22 126 8.4462.8 0.16 127 6.0470.6 0.19 127 5.3570.1 0.25 126 6.3066.3 0.22 126 6.6060.8 0.27 125 8.2559.1 0.26 125 8.6153.7 0.24 125 9.4758.6 0.27 125 8.97590.25 126 8.5463.7 0.27 126 7.9565.5 0.35 126 9.0062.6 0.51 127 11.5660.2 0.55 127 12.8660.2 0.58 126 13.1962.5 0.54 127 12.1875.4 0.7 126 11.0771.4 0.58 126 10.6669.8 0.56 126 10.8972.3 0.71 128 12.0567.9 0.94 128 14.8866.2 0.68 127 13.3055.8 0.66 126 15.3266.7 0.56 128 11.7189.4 0.78 128 9.4786.6 0.51 130 7.65106.7 0.83 129 7.74100.1 1.1 128 10.1190.8 1.06 127 11.1886.2 0.42 127 7.1979.4 0.31 126 6.6670.9 0.41 126 9.18730.36 126 8.1476.9 0.28 125 6.7360.5 0.22 127 8.8027.6 0.34 125 25.6525.9 0.51 124 31.5422.6 0.45 124 34.6618.2 0.54 120 NoLq200.89 130 NoLq43.8 1.15 130 28.3848.3 1.2 126 26.0827.8 0.72 123 34.4122.7 0.4 122 33.45220.47 120 74.5528.3 1.53 130 NoLq46.9 1.72 130 31.5151.4 1.32 130 26.2540.7 1.18 130 30.3039.7 1.62 135 35.04123.1 2.58 135 14.741824.65 135 13.21242.6 6.4 130 11.971665.8 135 16.711904.93 135 13.34203.2 4.54 135 11.57182.9 4.94 130 13.89118.1 4.69 140 21.6280.6 3.96 130 27.251183.18 130 18.1577.8 2.46 130 23.3449.7 1.45 125 27.2652.9 0.97 126 22.5255.1 1.11 130 22.5465.2 2.43 140 27.8481.9 4.03 135 27.16170.9 4.39 135 13.50397.9 4.37 130 Raw Unit Fines qc fc Weight %Shear Stress Ratio CRR CSR fs1 Shaded Zone has Liquefaction Potential 0 1 Soil DescriptionFactor of Safety051 Settlement Saturated Unsaturat. S = 2.84 in. 0 (in.)10 fs1=1.20 FIGUREPHASE PROFILE OF LIQUEFACTION SAFETY FACTORS AND INDUCED SETTLEMENT: GOLDER CPT-01 PARKWAY CAPITAL VIA 405 APTS 100 E-11771669 REDMOND 2017-03-17 CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_008.inddLiquefyPro CivilTech Software USA www.civiltech.comLIQUEFACTION ANALYSIS Via 405 Project Liquefaction Assessment: PGA=0.573; M=7 Plate A-1 Hole No.=CPT-02 Water Depth=5.5 ft Surface Elev.=28 Magnitude=7 Acceleration=0.573g (ft)0 5 10 15 20 25 30 35 22.9 .76 130 NoLq22.9 0.76 130 NoLq22.9 0.76 130 NoLq22.9 0.76 128 NoLq16.9 0.54 120 NoLq191.76 130 NoLq72.5 3.27 135 NoLq294.7 3 135 0.452912.44 135 0.00296.9 2.77 135 0.212802.66 135 0.47239.6 1.99 135 0.37194.3 1.68 135 0.951700.76 135 0.00181.9 2.31 135 3.41144.1 2.33 135 5.9399.2 1.88 135 8.7790.2 1.29 132 7.8684.8 1.04 129 7.29710.67 131 7.0560.8 0.64 130 9.3252.7 1.41 127 17.80450.82 130 16.2928.7 0.6 130 21.8422.6 0.44 126 25.0415.2 0.37 126 33.5115.6 0.41 130 31.5257.2 0.82 131 13.3460.6 1.01 133 13.4366.8 0.95 129 11.5771.5 0.78 131 9.6161.1 0.79 130 11.9847.3 0.92 130 17.8536.4 0.7 130 20.5731.9 0.51 130 20.5927.3 0.32 128 19.8522.1 0.23 126 21.4319.2 0.17 128 21.8719.6 0.12 122 19.26210.11 121 17.3921.7 0.1 121 16.4221.9 0.12 125 17.4219.6 0.13 125 19.9218.9 0.11 127 19.7919.6 0.14 127 20.5819.7 0.1 121 18.55210.09 121 16.8022.5 0.1 130 16.46250.23 130 19.9226.3 0.36 124 22.2331.1 0.24 126 16.04390.13 124 9.5142.4 0.09 124 7.3241.2 0.12 126 8.55370.31 124 14.8332.6 0.34 126 17.6136.7 0.3 126 15.0439.4 0.25 125 12.68340.23 130 14.92290.35 125 20.1334.3 0.27 125 15.9834.6 0.34 129 17.3325.7 0.44 130 25.4427.9 0.43 130 24.6130.4 0.66 130 26.7230.1 0.63 130 26.6231.7 0.68 130 26.4332.3 0.81 130 27.7543.4 1.24 130 25.7151.1 1.32 132 22.3277.1 1.5 127 16.0953113019.0928.4 0.73 127 29.5323.7 0.38 128 28.1025.2 0.46 128 28.2625.6 0.47 128 28.20790.75 130 10.6246.5 0.9 130 20.5332.5 1.01 130 30.6431.2 0.73 130 28.4331.1 0.67 130 27.9230.5 0.86 120 32.0433.7 2.08 120 NoLq38.6 2.22 130 36.5146.1 1.5 130 28.3637.5 1.03 130 28.0433.9 0.58 129 24.1829.6 0.47 130 25.4030.8 0.61 130 27.4435.5 1.08 130 30.55471.79 130 29.5257.7 1.75 130 24.8645.5 1.44 130 27.7535.1 1.01 129 30.2331.2 0.68 129 28.6731.5 0.67 128 28.5127.9 0.73 130 31.96370.72 130 25.3438.9 0.83 130 25.7533.2 0.9 130 30.3738.3 1.2 127 30.5157.9 1.17 132 19.72116.8 1.34 135 9.42132.2 1.45 135 8.01159.3 2.2 135 8.29201.4 3.16 135 7.79252.2 3.87 135 6.50327.2 4.64 130 4.90 Raw Unit Fines qc fc Weight %Shear Stress Ratio CRR CSR fs1Shaded Zone has Liquefaction Potential 0 1 Soil DescriptionFactor of Safety051 Settlement SaturatedUnsaturat. S = 2.58 in. 0 (in.)10 fs1=1.20 FIGUREPHASE PROFILE OF LIQUEFACTION SAFETY FACTORS AND INDUCED SETTLEMENT: GOLDER CPT-02 PARKWAY CAPITAL VIA 405 APTS 100 E-21771669 REDMOND 2017-03-17 CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_009.inddLiquefyPro CivilTech Software USA www.civiltech.comLIQUEFACTION ANALYSIS Via 405 Project Liquefaction Assessment: PGA=0.573; M=7 Plate A-1 Hole No.=CPT-03 Water Depth=7 ft Surface Elev.=28 Magnitude=7 Acceleration=0.573g (ft)0 5 10 15 20 25 30 35 6.4 .55 114 NoLq6.4 0.55 114 NoLq6.4 0.55 114 NoLq6.4 0.55 114 NoLq6.4 0.55 120 NoLq13.1 1.28 135 NoLq208.2 2.22 135 32.95303.6 3.2 135 0.47316.8 3.57 135 0.79277.3 3.03 135 1.02254.8 3.16 135 1.802252.41 135 1.55186.1 1.98 135 2.11145.8 1.45 135 2.76102.7 1.12 132 4.7861.8 0.91 130 9.84300.79 130 20.7923.4 0.66 120 26.3714.5 0.59 130 32.9718.8 0.78 120 32.0825.6 1.16 130 31.7327.5 0.3 135 15.34130.9 1.06 135 3.58113.9 2.1 130 8.9996.9 2.79 135 13.8987.9 2.07 130 13.18732.18 130 17.0058.4 1.73 135 18.1489.3 1.34 130 NoLq40.3 1.26 130 NoLq35.6 1.1 130 NoLq28.1 1.04 130 NoLq19.3 0.8 120 NoLq14.5 0.66 120 NoLq13.6 0.59 120 NoLq11.4 0.52 120 NoLq10.4 0.46 119 NoLq9.5 0.42 117 NoLq8.7 0.64 130 NoLq28.9 1.1 130 NoLq341.49 120 NoLq28.5 1.5 120 NoLq27.9 1.44 120 NoLq26.6 1.49 120 NoLq25.8 1.46 120 NoLq25.5 1.25 130 NoLq26.2 1.14 120 NoLq20.9 1.15 120 NoLq17.5 1.06 120 NoLq17.7 1.16 120 NoLq20.2 1.04 120 NoLq17.6 0.97 130 NoLq22.1 0.55 127 30.8147.1 0.5 127 14.9549.7 0.58 130 15.0440.1 0.71 130 20.4136.1 0.54 130 20.81340.61 130 23.25340.49 124 21.1234.1 0.37 124 18.6233.8 0.24 124 15.6235.5 0.17 124 12.8834.8 0.17 125 13.0438.8 0.2 126 12.4239.7 0.23 126 12.8245.7 0.42 128 14.3355.7 0.63 125 13.8452.6 0.31 126 10.9622.6 0.36 126 NoLq18.7 0.41 130 NoLq18.5 0.68 130 NoLq25.8 0.91 130 NoLq31.1 0.98 130 NoLq34.3 1.17 130 NoLq35.8 1.08 130 NoLq36.4 1.42 130 NoLq37.6 1.75 130 NoLq41.6 1.97 130 NoLq37.3 1.75 120 NoLq37.2 1.81 130 NoLq46.5 1.74 120 NoLq38.6 2 120 NoLq32.3 2.21 120 NoLq41.2 2.09 130 NoLq32.3 1.21 120 NoLq271.29 130 NoLq351.23 128 32.2664.5 1.02 127 17.0857.8 0.76 127 15.3576.3 0.53 126 8.9054.2 0.42 123 12.2847.1 0.25 125 11.9342.9 0.23 125 12.9440.7 0.38 125 16.9842.1 0.46 126 17.8346.1 0.49 126 16.7146.9 0.39 126 14.7847.2 0.27 126 12.5845.6 0.3 124 13.87400.43 130 18.6337.1 0.59 124 23.03380.3 124 17.2540.9 0.23 124 14.3438.5 0.29 123 16.4635.4 0.17 124 14.7640.7 0.19 125 13.4045.9 0.37 125 14.9058.9 0.47 126 12.5772.7 0.62 128 11.3373.1 0.83 128 13.1273.4 1.09 130 15.17821.25 128 14.3992.9 1.21 131 12.03117.6 1.33 135 9.26154.4 1.64 135 7.08194.9 2.21 135 6.19227.1 2.77 135 5.94228.6 3.39 135 7.08229.3 3.92 135 7.98234.8 2.79 135 5.73245.9 2.92 135 5.37245.2 3.09 135 5.72254.8 3.33 135 5.81270.7 3.94 135 6.34264.9 5.11 135 8.31239.7 4.75 135 9.16203.8 4.27 135 10.58166.7 3.65 135 12.29141.7 3.22 135 13.871382.86 135 13.311402.87 135 13.14143.3 3.11 135 13.52133.1 3.17 135 14.91136.3 3.1 134 14.57112.5 2.89 135 16.89121.4 2.87 135 15.70138.3 2.69 134 12.89149.9 2.46 134 10.87151.7 1.99 135 9.35138.1 2.4 131 11.91131.1 1.76 128 10.56104.3 1.37 128 12.1779.7 1.45 126 16.9384.4 0.77 127 11.3287.6 0.35 127 6.9887.7 0.39 127 7.0786.5 0.48 126 8.1879.4 0.45 126 9.0077.2 0.48 125 10.01680.67 126 13.8155.2 0.53 125 15.8253.1 0.4 124 14.6160.4 0.43 128 13.3577.8 1.08 130 15.29126.2 1.47 134 9.79194.6 1.89 135 6.19220.4 2.7 135 6.57260.8 3.25 130 Raw Unit Fines qc fc Weight %Shear Stress Ratio CRR CSR fs1 Shaded Zone has Liquefaction Potential 0 1 Soil DescriptionFactor of Safety051 Settlement Saturated Unsaturat. S = 2.50 in. 0 (in.)10 fs1=1.20 FIGUREPHASE PROFILE OF LIQUEFACTION SAFETY FACTORS AND INDUCED SETTLEMENT: GOLDER CPT-03 PARKWAY CAPITAL VIA 405 APTS 100 E-31771669 REDMOND 2017-03-17 CLIENT CONSULTANT PREPARED DESIGN PROJECT APPROVED TITLE REVIEW YYYY-MM-DD PROJECT No.Rev.G:\ParkwayCapital\405Appts\99_PROJECTS\1771669_RVA Cinema\100\02_PRODUCTION\INDD\1771669_100_010.inddLiquefyPro CivilTech Software USA www.civiltech.comLIQUEFACTION ANALYSIS Via 405 Project Liquefaction Assessment: PGA=0.573; M=7 Plate A-1 Hole No.=CPT-04 Water Depth=10 ft Surface Elev.=28 Magnitude=7 Acceleration=0.573g (ft)0 5 10 15 20 25 30 35 52.7 .75 110 NoLq52.7 0.75 110 3.7052.7 0.75 110 4.9652.7 0.75 110 5.8452.7 0.75 110 6.5452.7 0.75 129 7.1252.7 0.75 135 6.811100.77 135 1.07107.9 0.76 135 1.43100.9 1.03 135 3.17110.4 0.78 133 1.8786.9 0.95 134 4.82930.6 134 2.5293.4 0.67 133 2.96880.83 132 4.7261.6 1.03 130 10.5457.7 1.22 135 12.50115.7 1.75 135 7.09109.8 2.48 130 10.2191.8 2.41 130 12.75942.71 135 13.39120.2 2.48 135 9.451211.83 135 7.15142.6 1.79 135 5.231882.26 135 3.97217.6 2.88 135 3.99203.6 3.15 135 5.13199.2 2.5 135 4.32195.9 2.83 135 5.16176.7 2.83 135 6.45133.1 3.04 130 10.651023.2 130 NoLq73.2 2.29 120 NoLq25.8 1.61 120 NoLq11.5 0.49 114 NoLq6.5 0.3 113 NoLq6.6 0.28 123 NoLq12.2 0.24 121 NoLq23.3 0.17 126 NoLq41.8 0.26 132 NoLq69.7 1.36 133 NoLq96.4 1.28 134 NoLq1051.37 135 NoLq84.5 1.23 129 NoLq56.1 1.02 130 NoLq27.1 0.94 120 NoLq17.1 0.76 127 NoLq14.5 0.57 120 NoLq13.1 0.53 119 NoLq10.9 0.46 117 NoLq90.4 115 NoLq8.9 0.32 119 NoLq8.5 0.24 111 NoLq6.3 0.22 111 NoLq6.2 0.19 119 NoLq7.1 0.2 113 NoLq7.8 0.29 119 NoLq10.8 0.24 122 NoLq18.7 0.29 124 NoLq16.8 0.35 122 NoLq14.7 0.25 122 NoLq27.3 0.25 126 21.4224.5 0.29 124 24.74200.28 124 28.9820.1 0.19 120 25.7716.5 0.17 118 30.1810.9 0.21 118 NoLq7.6 0.19 118 NoLq7.5 0.19 117 NoLq8.3 0.13 118 NoLq7.3 0.14 108 NoLq50.14 108 NoLq5.1 0.14 108 NoLq5.2 0.18 108 NoLq5.4 0.19 108 NoLq5.7 0.21 108 NoLq5.4 0.23 110 NoLq60.31 111 NoLq7.3 0.38 113 NoLq80.45 111 NoLq7.5 0.45 110 NoLq6.3 0.23 108 NoLq5.7 0.27 94 NoLq3.1 0.22 110 NoLq5.9 0.22 111 NoLq6.9 0.2 110 NoLq6.7 0.19 110 NoLq6.1 0.16 110 NoLq5.8 0.15 116 NoLq5.5 0.13 108 NoLq5.4 0.15 110 NoLq5.8 0.17 110 NoLq6.2 0.18 109 NoLq60.19 109 NoLq6.1 0.2 109 NoLq6.4 0.19 116 NoLq70.18 109 NoLq6.2 0.19 108 NoLq5.4 0.2 108 NoLq5.2 0.23 109 NoLq60.25 108 NoLq5.4 0.21 108 NoLq5.4 0.16 108 NoLq4.9 0.15 114 NoLq5.4 0.12 94 NoLq5.9 0.09 116 NoLq60.11 119 NoLq9.7 0.29 122 NoLq16.9 0.45 124 NoLq18.4 0.45 115 NoLq10.9 0.42 122 NoLq12.2 0.45 125 NoLq160.64 130 NoLq230.89 123 NoLq18.2 0.62 122 NoLq15.7 0.32 119 NoLq15.7 0.11 122 30.3821.4 0.16 118 24.9425.8 0.08 122 16.9046.1 0.14 122 10.6447.5 0.15 124 10.1956.9 0.24 125 9.77680.24 127 7.5282.2 0.27 127 5.9390.2 0.35 127 5.8784.4 0.44 126 7.5572.7 0.37 124 8.72590.32 123 11.3138.8 0.54 124 22.2740.3 0.43 126 18.9572.3 0.26 127 7.8881.5 0.33 126 6.9675.8 0.41 126 8.6974.7 0.28 126 7.35740.25 126 6.9177.8 0.23 126 6.1478.6 0.25 126 6.2775.6 0.18 125 5.8172.5 0.2 124 6.54600.19 123 8.5454.3 0.18 123 9.6754.1 0.23 122 10.9248.1 0.27 124 13.3357.5 0.28 124 11.0960.1 0.37 124 11.5860.1 0.2 126 8.9680.1 0.32 126 7.2480.1 0.34 127 7.4689.6 0.41 126 6.9095.4 0.31 126 5.32980.37 127 5.6390.5 0.4 126 6.7682.5 0.34 126 7.1384.7 0.25 126 5.8395.6 0.29 126 5.061060.3 126 4.30103.4 0.34 127 4.9899.8 0.66 127 8.1497.4 0.92 127 10.30102.2 0.92 126 9.45103.6 0.08 126 2.44106.2 0.51 120 6.64130.43 127 32.2594.5 0.75 125 10.5656.3 0.49 126 15.3030.6 0.45 122 27.4919.4 0.56 127 NoLq34.8 0.59 124 27.7448.7 0.77 130 22.6144.9 0.94 123 25.73430.53 125 21.6751.9 0.6 129 18.7038.1 0.63 127 26.2126.3 0.73 127 NoLq20.3 0.81 130 NoLq33.1 0.95 124 90.9050.7 0.67 125 20.5170.2 0.65 126 14.4363.1 0.98 130 19.2046.5 0.96 128 25.8437.6 0.99 130 32.4529.8 1.33 130 NoLq29.2 1.24 127 NoLq30.3 1.12 129 NoLq430.99 130 29.7537.2 1.32 130 NoLq441.67 130 NoLq46.5 2.28 130 NoLq82.3 3.52 135 27.19184.4 4.69 130 Raw Unit Fines qc fc Weight %Shear Stress Ratio CRR CSR fs1Shaded Zone has Liquefaction Potential 0 1 Soil DescriptionFactor of Safety051 Settlement SaturatedUnsaturat. S = 3.21 in. 0 (in.)10 fs1=1.20 FIGUREPHASE PROFILE OF LIQUEFACTION SAFETY FACTORS AND INDUCED SETTLEMENT: GOLDER CPT-04 PARKWAY CAPITAL VIA 405 APTS 100 E-41771669 REDMOND 2017-03-17 Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation Golder Associates Inc. 18300 NE Union Hill Road, Suite 200 Redmond, WA 98052 USA Tel: (425) 883-0777 Fax: (425) 882-5498 Memorandum DATE: 03/20/2017 TO: Rick Tomkins, PE FROM: Richard Pratt Senior Biologist SUBJECT: Stream, Critical Areas, and Habitat Assessment PROJECT: VIA 405 Village Apartments (Roxy Cinema Redevelopment), Renton, WA PROJECT NO.: RVAC0000-0002 COPIES: File INTRODUCTION At the request of RVA Cinema LLC, David Evans and Associates, Inc. (DEA) conducted a stream and habitat assessment at the proposed VIA 405 Village Apartments property (parcel # 7232000010) on February 2, 2017, near the intersection of Rainier Avenue South and South Grady Way in Renton, Washington. The assessment was performed in support of a preliminary planned urban development (PPUD) application to redevelop the existing Roxy Cinema site into a 270- unit apartment project. The site visit was conducted to identify streams, wetlands, and habitat on or adjacent to the site. The project location is shown in Figure 1. One stream (Rolling Hills Creek) was identified in the study area. No wetlands or ditches were identified in the study area. Stream locations, as mapped by the City of Renton, are shown in Figure 2. Rick Tomkins, PE 03/20/2017 Page 2 Figure 1 Project Location METHODS Streams and their ordinary high water mark (OHWM) are defined by both the U.S. Corps of Engineers (Corps) and Ecology. The Corps (2014) guidance defines the OHWM as “that line on the shore established by the fluctuations of water and indicated by physical characteristics such as a clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate means that consider the characteristics of the surrounding areas.” Ecology’s guidance (Olson and Stockdale 2010) defines the OHWM for state waters. The following physical characteristics were used to identify the OHWM as defined by the Corps (2005): Natural line impressed on the bank Shelving changes in the character of soil Destruction of terrestrial vegetation Presence of litter and debris wracking Vegetation matted down, bent, or absent Sediment sorting Leaf litter disturbed or washed away Project Study Area Rick Tomkins, PE 03/20/2017 Page 3 Scour Deposition Multiple observed flow events Bed and banks Water staining Change in plant community Ditches may also be considered jurisdictional when they transport relatively permanent flow (continuous flow for at least three months) directly or indirectly into waters of the United States. All ditches within the study area were reviewed to determine if they meet the Environmental Protection Agency (EPA) and Corps guidance (EPA and Corps 2008) for being jurisdictional waters. In most situations, it was not possible to document whether a ditch or channel within the study project area has relatively permanent flows. The presence of an OHWM should be used as a baseline to establish the potential of relatively permanent flows. The OHWM and relatively permanent flow can be indicated by the following physical characteristics: Presence of a defined channel with bed and bank Areas exhibiting scour marks Debris wracks Shelving Water staining Areas of flowing or standing water Clear areas of gravel with no vegetation REGULATORY ANALYSIS The City of Renton Critical Areas Regulations are established in the Renton Municipal Code (RMC) 4-3-050. The City defines streams, stream classification, buffers, and alterations to these features as follows: RMC 4-3-050 section 7.Streams and Lakes: a. Classification System: The following classification system is hereby adopted for the purposes of regulating Streams and Lakes in the City. This classification system is based on the State’s Permanent Water Typing System WAC 222-16-030. Stream and lake buffer widths are based on the following rating system: i. Type S: Waters inventoried as “Shorelines of the State” under chapter 90.58 RCW. These waters are regulated under Renton’s Shoreline Master Program Regulations, RMC 4-3-090. ii. Type F: Waters that are known to be used by fish or meet the physical criteria to be potentially used by fish and that have perennial (year-round) or seasonal flows. Rick Tomkins, PE 03/20/2017 Page 4 iii. Type Np: Waters that do not contain fish or fish habitat and that have perennial (year-round) flows. Perennial stream waters do not go dry any time of a year of normal rainfall. However, for the purpose of water typing, Type Np waters include the intermittent dry portions of the perennial channel below the uppermost point of perennial flow. iv. Type Ns: Waters that do not contain fish or fish habitat and have intermittent flows. These are seasonal, non-fish habitat streams in which surface flow is not present for at least some portion of a year of normal rainfall and are not located downstream from any stream reach that is a Type Np Water. Ns Waters must be physically connected by an above-ground channel system to Type S, F, or Np Waters. b. Non-regulated: Waters that are considered “intentionally created” not regulated under this Section include irrigation ditches, grass-lined swales and canals that do not meet the criteria for Type S, F, Np, or Ns Non-regulated waters may also include streams created as mitigation. Purposeful creation must be demonstrated through documentation, photographs, statements and/or other persuasive evidence. c. Measurement: i. Stream/Lake Boundary: The boundary of a stream or lake shall be considered to be its ordinary high water mark (OHWM). The OHWM shall be flagged in the field by a qualified consultant when any study is required pursuant to this subsection G7. ii. Buffer: The boundary of a buffer shall extend beyond the boundaries of the stream or lake to the width applicable to the stream/lake class as noted in subsection G2 of this Section, Critical Area Buffers and Structure Setbacks from Buffers. Where streams enter or exit pipes, the buffer in this subsection shall be measured perpendicular to the OHWM from the end of the pipe along the open channel section of the stream. d. Stream/Lake Buffer Width Requirements: i. Buffers and Setbacks: (a) Minimum Stream/Lake Buffer Widths: See subsection G2 of this Section. (b) Piped or Culverted Streams: (1) Building structures over a natural stream located in an underground pipe or culvert except as may be granted by a variance in RMC 4-9-250 are prohibited. Transportation or utility crossings or other alterations pursuant to subsection J of this Section are allowed. Pavement over a pre-existing piped stream is allowed. Relocation of the piped stream system around structures is allowed. If structure locations are proposed to be changed or the piped stream is being relocated around buildings, a hydrologic and hydraulic analysis of existing piped stream systems will be required for any development project site that contains a piped Rick Tomkins, PE 03/20/2017 Page 5 stream to ensure it is sized to convey the one hundred (100) year runoff level from the total upstream tributary area based on future land use conditions. (2) No buffers are required along segments of piped or culverted streams. The City shall require easements and setbacks from pipes or culverts consistent with stormwater requirements in RMC 4-6-030 and the adopted drainage manual. ii. Increased Buffer Width: (a) Areas of High Blow-down Potential: Where the stream/lake buffer is in an area of high blow-down potential for trees as identified by a qualified professional, the buffer width may be expanded an additional fifty feet (50') on the windward side. (b) Habitat Corridors: Where the stream/lake buffer is adjacent to high functioning critical areas (e.g., wetlands, other streams, other identified habitats), the stream/lake buffer width shall be extended to the buffer boundary of the other protected critical area to establish a habitat corridor as needed to protect or establish contiguous vegetated areas between streams/lakes and other critical areas. e. Criteria for Permit Approval – Type F, Np, and Ns: Permit approval for projects on or near regulated Type F, Np and Ns water bodies shall be granted only if the approval is consistent with the provisions of this subsection, and complies with one of the following conditions: i. A proposed action meets the standard provisions of this Section and results in no net loss of regulated riparian area or shoreline ecological function in the drainage basin where the site is located; or ii. A proposed action meets alternative administrative standards pursuant to this Section and the proposed activity results in no net loss of regulated riparian area or shoreline ecological function in the drainage basin where the site is located; or iii. A variance process is successfully completed and the proposed activity results in no net loss of regulated riparian area or shoreline ecological function in the drainage basin where the site is located. RESULTS One stream (Rolling Hills Creek) was identified in the study area. Stream location is shown in Figure 2. No ditches were identified on the property. Rick Tomkins, PE 03/20/2017 Page 6 Figure 2 Stream Location From the City of Renton GIS Rick Tomkins, PE 03/20/2017 Page 7 ROLLING HILLS CREEK Rolling Hills Creek runs along the southern property boundary. The creek flows from a culvert 250 feet to the east along the property and enters one of two culverts 50 feet west of the project study area. Down stream a 48-inch stormwater culvert conveys lower flows to the west and then to the south. A second, large 12-foot culvert flows southwest. Both of these culverts are mapped by the City as ultimately discharging at the same location farther to the southwest. The stream culverts convey flow to a large wetland complex south of I-405 and east of SR-167, and then flow to Springbrook Creek which flows to the Green River. Rolling Hills Creek receives flow from the hill slope to the southeast of the study area and includes flow from Thunder Hills Creek. The confluence of Rolling Hills Creek and Thunder Hills Creek occurs in the culvert system to the east of the property study area. Within the property , the creek has been channelized along the existing development. The channel width is from 7 to 9 feet wide and the bank full width is from 12 to 13 feet wide. The bank full width was delineated and surveyed in the field. The stream bank is eroded with vertical to overhanging slopes 2 feet high. The stream bed through the study area is primarily gravel, sand, and fines with some cobble and areas of rip rap. There is little woody debris in the stream. There is trash and abandoned house hold items in both the stream and buffer areas. The stream buffer to the south extends to the right of way and structural wall for I-405. This buffer is 30 to 45 feet wide with trees, shrubs, and emergent vegetation. Buffer to the north extends to the existing parking lots on the property. This buffer area is 7 to 21 feet wide and includes some trees and emergent vegetation and little shrub vegetation. Rolling Hills Creek is not documented on Washington State Department of Natural Resources (WDNR) or Washington State Department of Fish and Wildlife (WDFW) online databases. There are documented salmon in Springbrook Creek downstream of the study area and Rolling Hills Creek. The City of Renton identifies the stream as a Type Np (non-fishbearing perennial) stream (Figure 3). A Type Np stream as defined by WAC 222-16-030 and RMC 4-3-050 is afforded a standard buffer width of 75 feet. Ordinary High Water Mark (OHWM) for Rolling Hills Creek The OHWM was delineated, flagged in the field, and the location was surveyed. A general map of the project site, existing conditions, and the OHWM is shown in Figure 3. Cross sections of the stream showing existing conditions and the proposed building conditions are shown in Figure 4. Rick Tomkins, PE 03/20/2017 Page 8 Figure 3 OHWM for Rolling Hills Creek in the project study area. Rick Tomkins, PE 03/20/2017 Page 9 Figure 4 Cross section of the study area and Rolling Hills Creek. Rick Tomkins, PE 03/20/2017 Page 10 WILDLIFE AND WILDLIFE HABITAT Habitat in the study area is limited to Rolling Hills Creek and its buffer. The study area is bordered on the south by I-405 and on the north by existing parking for the Roxy Cinema. This narrow corridor of habitat that is entirely surrounded by development. Trees along Rolling Hills Creek include: black cottonwood (Populus balsamifera), willow (Salix spp.), red alder (Alnus rubra), and Lombardy popular (Populus nigra). The understory includes both native western swordfern (Polystichum munitum) and salal (Gaultheria shallon) and invasive species including: Himalayan blackberry (Rubus armeniacus), reed canarygrass (Phalaris arundinacea), English ivy (Hedera helix), and English holly (Ilex aquifolium). Endangered Species Act (ESA) listed species, proposed species, critical habitat, or essential fish habitat (EFH) under the jurisdiction of the National Marine Fisheries Service (NMFS) and U.S. Fish and Wildlife Service (USFWS) that are recorded as potentially occurring in the project study area are listed in Table 1. The Washington Department of Natural Resources and Washington Department of Fish and Wildlife do not document rare plants, animals, or habitats within the study area or within a one-mile radius (WDFW 2017a, WDFW 2017b, WDNR 2017a. and WDNR 2017b). No suitable habitat for these species exists in the action area; therefore, the project would have no effect on the species. Table 1: USFWS and NMFS Listed Species and Critical Habitat in Snohomish County # Common Name Scientific Name Federal Status Jurisdiction 1. Bull trout Salvelinus confluentus Threatened USFWS 2. Marbled murrelet Brachyramphus marmoratus Threatened USFWS 3. Yellow-billed cuckoo Coccyzus americanus Threatened USFWS 4. Streaked horned lark Eremophila alpestris strigata Threatened USFWS 5. North American wolverine Gulo luscus Proposed Threatened USFWS Bull Trout and other salmonid species are not documented in Rolling Hills Creek nor are not documented in Spring Brook Creek. The neared record of bull trout is in the Green River (WDFW 2017a). If bull trout were present, they would not utilize Rolling Hills Creek due to the high levels of disturbance and poor habitat quality. The Green River, which represents the closest potential habitat for bull trout, is over three mile downstream of the project area. Therefore, the project will have no effect on bull trout. The marbled murrelet nests in old growth or mature forest stands, usually located within 50 miles of saltwater. The action area contains no suitable nesting habitat, does not support marine foraging habitat, and is not located in a major movement pathway (WDFW 2012). Therefore, the project would have no effect on marbled murrelets. The yellow-billed cuckoo is considered extirpated in Washington, with no known extant breeding population, and no documented occurrences in the action area (WDFW 2012; WDFW 2017b). Only a handful of sightings have been documented in Washington in the last few decades (SAS 2015). Therefore, the project would have no effect on yellow-billed cuckoo. The streaked horned lark is closely associated with the glacial outwash prairies of south Puget Sound and the outer coast (WDFW 2012), and has no potentially suitable habitat or documented Rick Tomkins, PE 03/20/2017 Page 11 occurrences in the project area (WDFW 2017b). Therefore, the project would have no effect on streaked horned lark. The North American wolverine occurs rarely in high-elevation alpine portions of Washington (WDFW 2012). The project site is well outside potential range of this species; therefore, the project would have no effect on North American wolverine. FLOODPLAINS Portions of the subject property are mapped as 100-year floodplain (Renton 2017). The location of the100-year floodplain is shown in Figure 5 below. Impacts The proposed project will have no direct impacts to Rolling Hills Creek. There will be no net loss of buffer along Rolling Hills Creek over existing conditions. The existing parking lot edge will remain unchanged. No culverts associated with the creek will be modified. Modifications to the stormwater system will be minimal. There will be some re-routing of storm water due to the new building footprint. The existing system will remain and there will be no changes to the existing points of discharge. Stormwater in the existing drainage system is first routed through an existing oil-water separator. As part of the proposed project work, additional treatment for the impacted pavement areas will be provided. The likely treatment facility will be a “Modular Wetland” filter vault. This improved treatment would have a beneficial effect on water quality in Rolling Hills Creek. RESTORATION Restoration of the riparian habitat along Rolling Hills Creek may be included in the project design. If restoration occurs, it will likely include the following actions: 1. Removing litter and artificial debris throughout the buffer. 2. Remove invasive plants (including Himalayan blackberry, reed canarygrass, English ivy, and English holly) in the buffer. 3. Plant native shrubs and groundcovers to protect slope and compete with invasive species. Native species that would deter access by people and pets can be used on the north side of the creek. 4. Install fencing to keep people and pets out of the stream and buffer. 5. Install signs designating the buffer and stream as protected areas. Rick Tomkins, PE 03/20/2017 Page 12 Figure 5 One Hundred Year floodplain and Floodway Boundary. Rick Tomkins, PE 03/20/2017 Page 13 REFERENCES Environmental Protection Agency and U.S. Army Corps of Engineers. 2008. Memorandum on Clean Water Act Jurisdiction Following the U.S. Supreme Court’s Decision in Rapanos v. United States & Carabell v. United States. Olson, P. and E. Stockdale. 2010. Determining the Ordinary High Water Mark on Streams in Washington State. Second Review Draft. Washington State Department of Ecology, Shorelands & Environmental Assistance Program, Lacey, Washington. Ecology Publication # 08-06-001. Renton, 2017. COR Maps. Accessed on March 16, 2017. Available at http://rentonwa.gov/government/default.aspx?id=29886 Seattle Audubon Society. 2015. BirdWeb – Yellow-billed cuckoo. Available at http://birdweb.org/birdweb/bird/yellow-billed_cuckoo. U.S. Army Corps of Engineers (Corps). 2005. Ordinary High Water Mark Identification. Regulatory Guidance Letter No. 05-05. The U.S. Army Corps of Engineers, Washington DC Washington Department of Fish and Wildlife (WDFW). 2012. Threatened and Endangered Wildlife in Washington: 2012 Annual Report. Listing and Recovery Section, Wildlife Program, Washington Department of Fish and Wildlife, Olympia. 251 pp. ———. 2017a. Salmonscape Fish Distribution Map. Accessed on March 16, 2017. Available at http://fortress.wa.gov/dfw/gispublic/apps/salmonscape/default.htm. ———. 2017b. Priority Habitats and Species (PHS) Online Mapper. Viewed on March 16, 2017. Available at http://wdfw.wa.gov/mapping/phs/. Washington State Department of Natural Resources (WDNR). 2017a. WDNR Natural Heritage Program GIS data. Dated September 18, 2014. ——. 2017b. Forest Practices Water Type Maps. Accessed on March 16, 2017. Available at http://fortress.wa.gov/dnr/app1/fpars/viewer.htm. Enclosures: Photographs VIA 405 Apartments Stream Appendix A Date 2017 Stream Memo Site Photographs Page A-1 Creek outlet into the 12‐foot and 48‐inch culverts approximately 50 feet down stream of property boundary February 2, 2017 Creek approximately 50 feet up stream of property boundary February 2, 2017 VIA 405 Apartments Stream Appendix A Date 2017 Stream Memo Site Photographs Page A-2 Creek in center of property showing up creek right bank view and existing buffer February 2, 2017 Creek in center of property showing up creek left bank view and existing buffer February 2, 2017 VIA 405 Apartments Stream Appendix A Date 2017 Stream Memo Site Photographs Page A-3 Creek in center of property showing down creek left bank view and existing buffer February 2, 2017 Creek in center of property showing down creek left bank view and existing buffer February 2, 2017 VIA 405 Apartments Stream Appendix A Date 2017 Stream Memo Site Photographs Page A-4 Creek substrate within the property boundary February 2, 2017 Creek showing rip rap and trash in the creek within the property boundary February 2, 2017 VIA 405 Apartments Stream Appendix A Date 2017 Stream Memo Site Photographs Page A-5 Creek with debris in the channel within the property boundary February 2, 2017 Creek substrate in area with rip rap within the property boundary February 2, 2017 VIA 405 Apartments Stream Appendix A Date 2017 Stream Memo Site Photographs Page A-6 Creek (looking down stream) with existing parking and curb within the property boundary February 2, 2017 Creek (looking up stream) with existing parking and curb within the property boundary February 2, 2017 Job No. RVAC0000-0002 Page 7-1 March 21, 2017 7 OTHER PERMITS The following approvals/permits will likely be needed for the Via 405 Apartments project (this list may not include all necessary permits). Permit Permittee Site Development Permit City of Renton SEPA Threshold Determination City of Renton NPDES Permit State Department of Ecology Stormwater Pollution Prevention Plan City of Renton Clearing and Grading Permit City of Renton Utility Permits City of Renton Building Permits City of Renton Job No. RVAC0000-0002 Page 8-1 March 21, 2017 8 CONSTRUCTION STORMWATER POLLUTION PREVENTION A Construction Stormwater Pollution Prevention Plan (SWPPP) will be prepared for the project at the final engineering stage. A separate SWPPP document will be prepared at the time of application for the required construction stormwater permit. Job No. RVAC0000-0002 Page 9-1 March 21, 2017 9 BOND QUANTITIES, FACILITY SUMMARIES AND DECLARATION OF COVENANT To be addressed at the final engineering stage. Job No. RVAC0000-0002 Page 10-1 March 21, 2017 10 OPERATIONS AND MAINTENANCE To be addressed at the final engineering stage.