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Home My WebLink About03816 - Technical Information Report � r � � COUGHLINPORTERLUNDEEN STRUCTURAL CIVIL SEISMIC ENGINEERING / DATE % PROJECT 04/03/15 Southport Hotel ! CLIENT ; CONTENT Mulvanny G2 Technical Information Report Architecture Permit#U14006572 ": ,,_�<: , ' � f�,,� ��,',.�.�„�, ', M. ;* , .. �, .�� _ r,f ',,' ,,.,.» -� '�` a+�; ,2:��-'��`��1--w-�'��w.- 'o'L.: - i�8�: -.rt'� - rt�" _a'�.r-� .� .F�., -4��<t _t+'... _ _ _ '�„'.` ..��-1!�a�.�%�: - „ , � . • . gyr. .J - . , �,; �� - i - • ' _..... . __ __ _...,, . . _ � � . - � ..w - - - - a _ .� _r - - - � _._• � " #� C ��_ �� 4 __ � .� ._ �` ' �^ '' �; . _ .� _ '�I ,' J�, �s.l, '�'^T `�� \_ s��'� ..- � .. '�"R:'��.'�i�c;:.r- . -.;�-a��;:i"�Q��Y-�?�� xM.��. �p.�- �. �i.. •.. -. ".. ... . . _ . .. . , i$.�,. . � .. . ,! .. ;; "" _ , � F P .rC . .�: 'Ic"w�.L�t'`'`.�:1:�. - F �� y� '� /j� COUGHLINPORTERLUNDEEN �, � � ---------- ------- -- � ENGINEERING REPORT ; .� ,�Technical Information Report ,` tn rtH t i �/ sou po o e ;/ Renton,WA Permit#U14006572 / � � / ��:j %� ,/ PREPARED FOR: %;;�/ SECO Development j 1083 Lake Washington Blvd N, Suite 50 , -,� Renton,WA 98056 �/ (425)282-5833 . ,'/ PREPARED THROUGH: j Mulvanny G2 Architecture ;,j ��L P� 1110 112th Avenue NE, Suite 500 ,;/ � v�� ,�T� Bellevue,WA 98004 %� � ,�.v �L Phone: (425)463-1371 , � :�, '%i � �� , , '� � PREPARED BY: ;'j � COUGHLIN PORTER LUNDEEN ;j � _ ?'r 36936 h,�' 801 Second Avenue, Suite 900 %.,�� ° � Seattle,WA 98104 '� ��rsTER 1 ;;-�,; � ��.�` P 206.343.0460 '';%� ��'�AL CONTACT/ Bart Balko, P.E. �'�;%�,;/ � , ;/, ' �� I� Drainage Report �� The Hotel at Southport ./ Coughlin Porter Lundeen / Project Number: C14-0507-01 / March 16, 2015 TABLE OF CONTENTS I. PROJECT OVERVIEW.....................................................................................................................................1 GeneralDescription..........................................................................................................................................1 ExistingConditions...........................................................................................................................................1 � ProposedDrainage System..............................................................................................................................1 II. CONDITIONS AND REQUIREMENTS SUMMARY ........................................................................................3 � City of Renton Amendments to the King County Surface Water Management Design Manual Core /;; Requirements: ..................................................................................................................................................3 � � j,'", SpecialRequirements:......................................................................................................................................3 / / Project Specific Requirements:.........................................................................................................................4 /: III. OFF-SITE ANALYSIS. j ....................................................................................................................................5 �;, Task 1 —Study Area Definition and Maps ........................................................................................................5 Task2- Resource Review................................................................................................................................5 j /' Task3- Field Inspection...................................................................................................................................5 j Task 4- Drainage System Description and Problem Descriptions...................................................................5 UpstreamAnalysis........................................................................................................................................5 DownstreamAnalysis....................................................................................................................................6 Task 5—Mitigation of Existing or Potential Problems.......................................................................................6 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN.......................................7 ';' ExistingSite Hydrolo9Y iPart A).......................................................................................................................7 �, Developed Site Hydrolo9Y�Part B)...................................................................................................................7 ;' Performance Standards and Flow Control System (Parts C and D)............ " .....................................................8 Water Quality System (Part E)........................................ . .............8 '' V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN.....................................................................................9 '' Standard Requirements(based on KCSWDM and SAO):................................................................................9 ;;� On-site Conveyance.......................................................................................................................................10 �% ExistingConditions:.....................................................................................................................................10 ; Developed Storm system description:.........................................................................................................10 '; Conveyance/Backwater Analysis:.............................................................................................................10 ; VI.SPECIAL REPORTS AND STUDIES...........................................................................................................11 VII.OTHER PERMITS.......................................................................................................................................12 VIII. CSWPPP ANALYSIS AND DESIGN..........................................................................................................13 StandardRequirements..................................................................................................................................13 IX. BOND QUANTITY, FACILITY SUMMARIES,AND DECLARATION OF COVENANT...............................14 X. OPERATION AND MAINTENANCE MANUAL.............................................................................................15 .,- StandardMaintenance....................................................................................................................................15 ' ; �, Figures..............................................................................................................................................................25 , I', AppendixA.......................................................................................................................................................26 ' AppendixB.......................................................................................................................................................27 ' " II AppendixC.......................................................................................................................................................28 'I j�i 80� SECOND AVENUE. SUITE 900 SEATTLE. 't�'A 98t0�t � �?i,5 :�3 O�bC� � cp r -;_corn �� /:'; , � % = COUGHLINPORTERLUNDEEN /�� . / LIST OF FIGURES FIGURE 1 -TIR WORKSHEET / FIGURE 2-PARCEL CONDITIONS FIGURE 3-SITE LOCATION FIGURE 4-PROPOSED CONDITIONS FIGURE 5-DRAINAGE BASIN MAP FIGURE 6-FLOW CONTROL MAP FIGURE 7-KING COUNTY IMAP-FLOODPLAIN FIGURE 8-CITY OF RENTON SOIL SURVEY MAP FIGURE 9-DRAINAGE COMPLAINTS MAP LIST OF TABLES TABLE 1 -EXISTING SITE CONDITIONS AREA BREAKDOWN TABLE 2- DEVELOPED SITE CONDITIONS AREA BREAKDOWN i / / ;;�;j ;j ;�j;/ � ;� �� j ;j 'j ,j, i % COUGHLINPORTERLUNDEEN �-' ��: �/, � �;. I. PROJECT OVERVIEW �, f �; GENERAL DESCRIPTION �; �The following preliminary Technical Information Report(TIR)provides the technical information and design /�;, � ,, analysis required for developing the Drainage Plan and the Temporary Erosion and Sedimentation Control � Plan (TESC)for the Hotel at Southport.The stormwater design for the project was based on the requirements %i�;� set forth in the City of Renton Amendments to the 2009 King County Surface Water Design Manual �; (KCSWDM)(See Figure 1 —Technical Information Report Worksheet)and the 2009 KCSWDM. � /," The Hotel at Southport project is located within the City of Renton, situated at the southern tip of Lake �. Washington to the west of the Gene Coulon Memorial Beach Park(See Figure 3—Site Location).The site is in ��': the NW '/<of the NW '/4 of Section 8, Township 23 North, Range 5 East, Willamette Meridian. The site will /� :� occupy lots 0823059216 and 0523059075,with areas of 187,460-SF and 296,821-SF, respectively. The entire j�; project resides on a combined lot size of 484,281-SF or approximately 11.12-acres. It should be noted that � ; approximately half of the latter parcel (0523059�75)extends into Lake Washington. The project is part of a � ;j� master plan which began in the late 1990's.A development agreement is in place with the city. The master j plan includes two residential buildings, Bristol 1 and Bristol 2,which ha�e been constructed, the hotel and a �; future office building and associated structured parking located south of the hotel. /�' ��; Overall, the project will include a 12-story hotel and general site improvements including landscaping, a ji tem ora surface arkin area, and a erimeter fire lane.The existin site consists of 2.5 acres of im ervious / P �Y P 9 P 9 P '/; area and 5.49 acres of pervious area.The proposed conditions will consist of approximately 7.09 acres of ��, impervious area and 0.9 acres of pervious area.Soils for the area were mapped using the King County Soil � Survey maps (See Figure 8—Soil Survey Map). -j Runoff from the site will be discharged directly to Lake Washington via pipe flow through existing conveyance j; connections to the lake. No new lake connections are proposed. �; ,� EXISTING CONDITIONS '�%' The existing site consists of asphalt and gravel parking lots as well as open grassy areas. See Table 1 for site �j' "�' surface cover information. The site was previously home to the Shuffleton Steam Plant,which was built in the �% �;. 1930's and demolished in 2001. Portions of the steam plant infrastructure are still in place, including a large � � . underground concrete vault,which this project proposes to reuse to provide water quality treatment for runoff j" from the surface parking lot. Refer to Section IV for more information. Minimal conveyance systems exist / j within the pro�ect site area. However, existing systems are located to the east which were constructed with / prior projects. Infrastructure was put in place for future development, including the hotel project. / �;; ,� , j' / �� /, % j ' I 801 SECOND AVENUE, SUITE 900 SEATTLE, WA 98104 / P 20fi.343.0460 ! cplinc.com /`' ' /- COUGHLINPORTERLUNDEEN PROPOSED DRAINAGE SYSTEM According to Table 1.1.2.A of the City of Renton Amendments to the King County Surface Water Manual (COR-SWM), this project meets the criteria for a Full Drainage Review, including flow control and water quality requirements. Since the project is within a basic water quality treatment basin discharging directly to a major receiving body, Basic water quality treatment for runoff from all target pollution generating surfaces will be provided by either one of two existing wet vaults �r a cartridge filter system before being discharged to Lake Washington. Conveyance for the site will be a combination of closed 6 to 12-inch pipes and sheet flow. Storm water runoff from the parking areas will be captured by a series of catch basins and routed the large wet vault. All conveyance on site will be designed according to Chapter 4 of the City of Renton Amendments to the KCSW DM. � 'i �� 2 COUGHLINPORTERLUNDEEN ' II. CONDITIONS AND REQUIREMENTS SUMMARY This section will address the requirements set forth by the Core and Special Requirements listed in Chapter 1 of the City of Renton's Amendments to the King County Surface Water Design Manual. CITY OF RENTON AMENDMENTS TO THE KING COUNTY SURFACE WATER MANAGEMENT DESIGN MANUAL CORE REQUIREMENTS: 1. Discharge at the Natural Location (1.2.1): All runoff from the site will be conveyed to the natural discharge location (Lake Washington). 2. Off-site Analysis (1.2.2): Refer to Sections III and IV.A Level 1 downstream analysis has been performed 3. Flow Control (1.2.3.1): Refer to Section IV. Since the project discharges directly to Lake Washington, flow control is not required. 4. Conveyance System (1.2.4): Refer to Section V. Closed pipe systems have been provided for on- site stormwater conveyance. 5. Erosion and Sedimentation Control (1.2.5): Refer to Section VIII. The project will construct a series of sediment controls to address the specific conditions at the site. 6. Maintenance and Operations(1.2.6): Refer to Section X. The proposed storm drainage system will be owned, operated and maintained by the owner. 7. Financial Guarantees and Liability(1.2.7): The owner and contractor will obtain all necessary permits and bonds prior to the beginning of construction. 8. Water Quality (1.2.8): Refer to Section IV.E.Water quality treatment for runoff from target pollution generating surfaces will be provided by a wet vault or StormFilter cartridge system. SPECIAL REQUIREMENTS: Special Requirement#1. Other Adopted Area-Specific Requirements Section 1.3.1 • Critical Drainage Areas (CDAs}: Not Applicable • Master Drainage Plans (MDPs):There are no known master drainage plans covering this project site OTHER THAN THE Master Plan for the Southport development. • Basin Plans (BPs): The project is located within Lower Cedar River Drainage Basin. • Lake Management Plans(LMPs): Not Applicable • Shared Facility Drainage Plans(SFDPs): Not Applicable Special Requirement#2. Flood Hazard Area Delineation, Section 1.3.2: See Figure 7 for 100-yr flood zone. No work affecting the flood storage will take place within the 100-yr flood zone. Special Requirement#3. Flood Protection Facilities, Section 1.3.3: Not Applicable Special Requirement#4. Source Controls, Section 1.3.4: See attached Activity Worksheet and Required BMP's. �� o ��I THE H^_�TE��_ A �� UTH� OPT 3 I COUGHLINPORTERLUNDEEN Special Requirement#5. Oil Control: Minimal traffic is anticipated in this area. No oil control is required. Special Requirement#6. Aquifer Projection Area: Project is not within an Aquifer Projection Area Zone. PROJECT SPECIFIC REQUIREMENTS: There are no additional requirements for this portion of the project. Design and construction will abide by requirements set forth in these documents and King County. I , THE HOTEL AT SOUTHPORT 4 COUGHLINPORTERLUNDEEN ' III. OFF-SITE ANALYSIS TASK 1 — STUDY AREA DEFINITION AND MAPS The Renton drainage basin map was used to verify that the site was fully in the Lower Cedar River drainage basin(See Figure 4—Drainage Basin Map). TASK 2 - RESOURCE REVIEW a) Adopted Basin Plans Lower Cedar River Drainage Basin b) Floodplain/floodway(FEMA) Maps Site is not located in the floodplain (See Figure 7) c) Off-site Analysis Reports NIA d) Sensitive Areas Folio See Figures 7—King County iMAP e) Drainage Complaints and Studies See Figure 9 f) Road Drainage Problems N/A g) King County Soils Survey: See Figure 8—City of Renton Soil Survey Map h) Wetland Inventory Maps: No Wetlands i) Migrating Rivers Study N/A j) DOE's Section 303d List of Polluted Waters k) KC Designated Water Quality Problems No WQ Problems I) City of Renton critical maps: No Critical Areas TASK 3 - FIELD INSPECTION Site visits have been made to gather information including an analysis of the discharge from the site. Please refer to Task 4, Downstream Analysis below for more information. TASK 4 - DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS Runoff from the site will be conveyed to an existing storm system that discharges directly to Lake Washington. The parking area will be routed to the wet vault before being pumped out t�the existing storm system in the private access road to the northeast of the site. Similarfy, runoff from the building roof and surrounding hardscapes will be collected and routed to existing storm systems to the northeast and southwest of the hotel building, both of which directly discharge to Lake Washington.An existing discharge tunnel is situated along the west side of the site,west of the hotel building. This tunnel provides a direct connection to the lake and will be utilized for storm discharge for this project. Upstream Analysis The site is within the Lake Washington East drainage basin.An existing conveyance pipe is routed through the site and discharges runoff to Lake Washington.This existing bypass pipe conveys runoff from the adjacent PSE property to the south.As part of a separate permit, this pipe will be intercepted at the property line and rerouted along the perimeter of the site, discharging to the existing discharge tunnel as it does currently. 5 COUGHLINPORTERLUNDEEN Downstream Analysis The site discharges directly to Lake Washington via existing pipe conveyance and existing outfalls to the lake. TASK 5 — MITIGATION OF EXISTING OR POTENTIAL PROBLEMS ' There are no known problems drainage complaints downstream of the site(See Figure 9). No mitigation is proposed. ; THE HOTEL AT SOUTHPORT 6 COUGHLINPORTERLUNDEEN IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN EXISTING SITE HYDROLOGY (PART A) The existing site totals 7.99 acres and consists of an existing asphalUgravel parking lot and a grass field.The site generally slopes to the northwest with drainage described in Section III Downstream Analysis.These conditions are summarized in Table 1 below. TABLE 1 - EXISTING SITE CONDITIONS AREA BREAKDOWN LAND COVER AREA(ACRES) DESCRIPTION Impervious Area 2.50 acres Asphalt and gravel parking areas Pervious& Landscape 5.49 acres Grass field Total Project Area 7.99 acres Total site area Percentage of Impervious Area 31% DEVELOPED SITE HYDROLOGY (PART B) The developed site hydrology will increase the amount of impervious area by approximately 4.59 acres.A summary of the basin information is shown in Table 2. TABLE 2- DEVELOPED SITE CONDITIONS AREA BREAKDOWN LAND COVER AREA(ACRES) DESCRIPTION Impervious Area 7.15 acres Building roof, parking areas,drive aisles,fire lane Pervious& Landscape 0.84 acres Associated landscaping, undisturbed areas Total Project Area 7.99 acres Total site area Percentage of Impervious Area 89% 'HE H�TE'�_ A,T �^,�T�iFO!?T 7 � COUGHLINPORTERLUNDEEN PERFORMANCE STANDARDS AND FLOW CONTROL SYSTEM (PARTS C AND D) According to Section 1.2.3.1 (and the Flow Control Basin Map)of the City of Renton Amendments to the KCSWM, this project is located within the Peak Flow Control area. However,since this project discharges directly to Lake Washington and satisfies all of the Direct Discharge Exemption criteria (discussed below),flow control is not required. Direct Discharge Exemption Criteria: a. The project site discharges to Lake Washington b. The conveyance system between the project site and the major receiving water(Lake Washington) will extend to the ordinary high water mark, and will be comprised of manmade c�nveyance elements (pipes)and will be within a public or private drainage easement. c. The conveyance system will have adequate capacity to convey the 25-year peak flow(per Core Requirement#4, Conveyance System)for the entire contributing drainage area. d. The conveyance system will be adequately stabilized to prevent erosion e. The direct discharge proposal will not divert flows from or increase flows to an existing wetland or stream sufficient to cause a significant ad�erse impact. WATER QUALITY SYSTEM (PART E) Section 1.2.8.1(A)of the City of Renton Amendments to the KCSWDM outlines the specific land uses within Basic WQ Treatment areas which are subject to providing Enhanced Basic WA treatment. Being a commercial land use, the Hotel at Southport project falls into the category of Enhanced Basic WQ Treatment. However, exception number 3 of Section 1.2.8.1(A)states that "The Enhanced Basic WQ menu as specifred above for certain land uses may be reduced fo the Basic WQ menu for treatment of any runoff that is discharged directly, via a non-fish-bearing conveyance system, all the way to the ordinary high water mark of a sfream with a mean annua!flow of 1,000 cfs or more(at fhe discharge poinf of the conveyance system)or a lake that is 300 acres or larger" Since this project will discharge runoff directly to Lake Washington (approximately 21,500 acres)via a piped connection, it would follow that the project is exempt from providing Enhanced Basic WQ treatment. Similarly, the"IntenY' paragraph of Section 1.2.8.1(A)states that, `projects that drain entirely by pipe to fhe major receiving waters Jisted on page 1-33 jone of which is Lake Washington]are excused from the increased treatment and may revert to the Basic WQ menu because concentrafion effects are ofless concern as the overall flow volume increases." Therefore, basic water quality treatment for all new and replaced pollution generating impenrious surfaces (PGIS)will be provided by either a wetvault or a StormFilter cartridge system, depending on location.As shown on Figure 4,the project will have four separate pollution generating surfaces; the 4.61 acre temporary THE HOTELAT SOUTHPOR� g COUGHLINPORTERLUNDEEN _ __ surface parking lot, the 0.55 acre porte cochere (hotel entry loop),the 1.7 acre loading area and associated west access road, and the 0.4 acre eastern access drive. As shown in Figure 4—Proposed Conditions,the parking lot will be treated by an existing underground vault. Following the procedure outlined in section 6.4.1.2 of the KCSWDM, the required wetpool volume for the parking lot is 20,007 CF (see Appendix A—Water Quality Treatment Calculations).As mentioned in Section I, the existing underground vault which was previously used by the Shuffleton Steam Plant to store distilled water. The project proposes to reuse the existing vault as a wetvault to provide basic treatment for a portion of the new PGIS. The information available indicates that the vault has inside dimensions of approximately 178.5'x45'x10' and has a series of internal baffles. Also shown in Figure 4, the loading area and associated west access road will be treated by a StormFilter cartridge system before discharging to Lake Washington through the existing discharge tunnel. The cartridge filter system was sized using the water quality design flow rate(35%of the 2-yr peak flow)of 115.93 gpm. Per DOE, each 27"cartridge can treat 11.3 gpm, resulting in a need for 11 cartridges to treat the runoff. The existing eastern access drive will be treated by another Stormfilter cartridge system, sized to handle the proposed runoff, before discharging to an existing 24"storm sewer which will ultimately discharge to Lake Washington. The cartridge filter system was sized using the water quality design flow rate(35%of the 2-yr peak flow)of 27.65 gpm. Each 18"cartridge has a 7.5 gpm treatment capacity,so 4 cartridges will be required. Runoff from the porte cochere will be routed to an existing water quality treatment vault located southeast of the hotel site near Bristol 1. Previous calculations (from the Master Plan)for the existing vault show that it has � the capacity for future build-out conditions,which included the porte cochere area of the hotel. V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN This section discusses the criteria that will be used to analyze and design the proposed storm conveyance system. STANDARD REQUIREMENTS (BASED ON KCSWDM AND SAO): 1. Facilities must convey the 100-year flow without overtopping the crown of the roadway, flooding buildings,and if sheet flow occurs it must pass through a drainage easement.All stormwater conveyance has been designed such that the 100-year flow is conveyed without overtopping the crown of the roadway(or drive aisle)or flooding any building. 2. New pipe systems and culverts must convey the 25-year flow with at least 0.5 feet of freeboard. (1.2.4-1). The new pipe systems have been designed to convey the 25-year flow with at least 0.5 feet of freeboard. 3. Bridges must convey the 100-year flow and provide a minimum of two feet,varying up to six feet, of clearance based on 25%of the mean channel width. (1.2.4-2)(4.3.5-6). N/A. This project does not propose a bridge. s COUGHLINPORTERLUNDEEN 4. Drainage ditches must convey the 25-year flow with 0.5 feet of freeboard and the 100-year flow without overtopping.(1.2.4-2). N/A This project does not propose a drainage ditch. 5. Floodplain Crossings must not increase the base flood elevation by more than 0.01 feet [41(83.C)] and shall not reduce the flood storage volume [37(82.A)]. Piers shall not be constructed in the FEMA floodway. [41(83.F.1)]. No work is being proposed within the base flood elevation or within the FEMA floodway. 6. Stream Crossings shall require a bridge for class 1 streams that does not disturb or banks. For type 2 and type 3 steams, open bottom culverts or other method may be used that will not harm the stream or inhibit fish passage. [60(95.B)]. There are no new stream (river) crossings associated with the construction of this project. 7. Discharge at natural location is required and must produce no significant impacts to the downstream property(1.2.1-1).The project will discharge to the existing storm system. ON-SITE CONVEYANCE Existing Conditions: Runoff from the existing site is generally collected into catch basins via sheet flow and is routed directly to the outfall to Lake Washington. Developed Storm system description: Runoff from the building roof will be collected into roof drains and routed directly to Lake Washington via pipe flow. Site runoff will generally be collected by catch basins and trench drains before being routed either directly to Lake Washington (NPGIS)or a water quality treatment facilities(PGIS). Conveyance / Backwater Analysis: A conveyance analysis has been performed on each basin within the site, per the King County Surface Water Design Manual . See Appendix A for more information. �o COUGHLINPORTERLUNDEEN VI. SPECIAL REPORTS AND STUDIES Geotechnical Report—500 Fairview Ave North Seattle,Washington, dated April 25th, 2011; By Terra Associates, Inc. See Appendix B. I � � 'I - �� COUGHLINPORTERLUNDEEN VII. OTHER PERMITS This project will require building and demolition permits from the City of Renton and a CSWPPP. See Section 8 for the CSW PPP. An early Clear&Grade Permit(U140044341)and an early Utility Permit(U14005809)were approved with the City for this project development. The project has obtained coverage under an NPDES permit with the Washington State Department of Ecology. 12 COUGHLINPORTERLUNDEEN VIII. CSWPPP ANALYSIS AND DESIGN This section lists the requirements that will be used when designing the TESC plan for this site. A copy of the SWPPP is included in Appendix C. STANDARD REQUIREMENTS ErosionlSedimentation Plan shall include the following: 1. Facilities required include: Catch basin filter socks. (1.2.5-1). The project will provide sediment protection at existing and proposed catch basins. 2. Timing-For the period between November 1 through March 1 disturbed areas greater than 5,000 square feet left undisturbed for more than 12 hours must be covered with mulch, sodding, or plastic covering.A construction phasing plan shall be provided to ensure that erosion control measures are installed prior to clearing and grading. (1.2.5-1). The TESC plan will include provisions for disturbed areas to be covered in accordance with City of Renton requirements and that all TESC measures are in place before any construction activity occurs. 3. Planning-Plan shall limit tributary drainage to an area to be cleared and graded. Delineate dimension,stake and flag clearing limits (1.2.5-1�. The clearing limits will be indicated on the TESC plan. 4. Revegetation - Revegetate areas to be cleared as soon as practicable after grading. (1.2.5-1). Notes addressing this item will be included on the TESC plan. Note: site TESC measures were approved as part of the Clear&Grade Permit(U140044341). Additional measures beyond those previously approved are not proposed. Additionally,the project has obtained coverage under an NPDES permit with the State Department of Ecology and is complying with all requirements of that permit. 13 COUGHLINPORTERLUNDEEN IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION OFCOVENANT A Bond Quantity Worksheet, if required, is not included at this time. A Water Quality Facility Summary Sheet outlining the proposed water quality system will be submitted following approval of the plans, if required. Any required Declarations of Covenant, if required, will be included prior to issuance of the permit. 14 COUGHLINPORTERLUNDEEN X. OPERATION AND MAINTENANCE MANUAL STANDARD MAINTENANCE Per standards set forth in the King County Surface Water Design Manual, the owner will maintain facilities. Sections of the King County Storm Water Management Design Manual outlining the Operations and Maintenance of these facilities have been included in this section on the following pages. : , 15 COUGHLINPORTERLUNDEEN MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES AT THE HOTEL AT SOUTHPORT NO. 2-CLOSED DETENTION SYSTEMS (VAULTS) Maintenance Defect Conditions When Maintenance is Results Expected When Component Needed Maintenance is Performed Storage Area Plugged Air One-half of the cross section of a vent is Vents free of debris and Vents blocked at any point with debris and sediment sediment Debris and Accumulated sediment depth exceeds All sediment and debris Sediment 10% of the diameter of the storage area removed from storage for Y�length of storage vault or any point area. depth exceeds 15%of diameter. Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than '/2 length of tank. Manhole Cover Not in Cover is missing or only partially in place. Manhole is closed. Place Any open manhole requires maintenance. Locking Mechanism cannot be opened by one Mechanism opens with Mechanism maintenance person with proper tools. proper tools. Not Working Bolts into frame have less than '/inch of thread (may not apply to self-locking lids.) Cover Difficult One maintenance person cannot remove Cover can be removed to Remove lid after applying 801bs of lift. Intent is to and reinstalled by one keep cover from sealing off access to maintenance person. maintenance. Ladder Rungs King County Safety Office and/or Ladder meets design Unsafe maintenance person judges that ladder is standards allows unsafe due to missing rungs, maintenance person safe misalignment, rust, or cracks. access. Catch Basins See"Catch Basins"Standards No.4 See"Catch Basins" Standards No.4 is COUGHLINPORTERLUNDEEN NO.4-CATCH BASINS Maintenance Defect Conditions When Maintenance is Results Expected Component Needed When Maintenance is perFormed General Trash & Debris Trash or debris of more than 1/2 cubic foot No Trash or debris (Includes which is located immediately in front of the located immediately in Sediment) catch basin opening or is blocking capacity fr�nt of catch basin of the basin by more than 10% opening. Trash or debris (in the basin)that exceeds No trash or debris in the 1/3 the depth from the bottom of basin to catch basin. invert the lowest pipe into or out of the basin. Trash or debris in any inlet or outlet pipe Inlet and outlet pipes free blocking more than 1/3 of its height. of trash or debris. Dead animals or vegetation that could No dead animals or generate odors that could cause vegetation present within complaints or dangerous gases (e.g., the catch basin. methane). Deposits of garbage exceeding 1 cubic No condition present foot in volume which would attract or support the breeding of insects or rodents. Structure Corner of frame extends more than 3/4 Frame is even with curb. Damage to inch past curb face into the street(If Frame and/or applicable). Top Slab Top slab has holes larger than 2 square Top slab is free of holes inches or cracks wider than 1/4 inch (intent and cracks. is to make sure all material is running into basin). Frame not sitting flush on top slab, i.e., Frame is sitting flush on separation of more than 3/4 inch of the top slab. frame from the top slab. 17 COUGHLINPORTERLUNDEEN NO. 4-CATCH BASINS (CONTINUED) Maintenance Defect Condition When Maintenance is Results Expected Components Needed When Maintenance is Performed. Cracks in Basin Cracks wider than 1/2 inch and longer Basin replaced or Walls/Bottom than 3 feet, any evidence of soil particles repaired to design entering catch basin through cracks, or standards. maintenance person judges that structure is unsound. Cracks wider than 1!2 inch and longer No cracks more than 1/4 than 1 foot at the joint of any inleU outlet inch wide at the joint of pipe or any evidence of soil particles inlet/outlet pipe. entering catch basin through cracks. Sediment/ Basin has settled more than 1 inch or Basin replaced or Misalignment has rotated more than 2 inches out of repaired to design alignment. standards. Fire Hazard Presence of chemicals such as natural No flammable chemicals gas, oil and gasoline. present. Vegetation Vegetation growing across and blocking No vegetation blocking more than 10%of the basin opening. opening to basin. Vegetation growing in inleUoutlet pipe No vegetation or root joints that is more than six inches tall growth present. and less than six inches apart. Pollution Nonflammable chemicals of more than No pollution present 1/2 cubic foot per three feet of basin other than surface film. length. Catch Basin Cover Not in Cover is missing or only partially in Catch basin cover is Cover Place place.Any open catch basin requires closed maintenance. Locking Mechanism cannot be opened by on Mechanism opens with Mechanism Not maintenance person with proper tools. proper tools. Working Bolts into frame have less than 1/2 inch of thread. Cover Difficult One maintenance person cannot remove Cover can be removed to Remove lid after applying 80 Ibs. of lift; intent is by one maintenance keep cover from sealing off access to person. maintenance. �s COUGHLINPORTERLUNDEEN _ __ ___ _ __ __ __ _ _ Ladder Ladder Rungs Ladder is unsafe due to missing rungs, Ladder meets design I, Unsafe misalignment, rust, cracks, or sharp standards and allows ', edges. maintenance person safe access. ' Metal Grates Grate with opening wider than 7!8 inch. Grate opening meets (If Applicable) design standards. ' Trash and Trash and debris that is blocking more Grate free of trash and Debris than 20% of grate surtace. debris. Damaged or Grate missing or broken member(s)of Grate is in place and Missing. the grate. meets design standards. NO. 7- FENCING Maintenance Defect Conditions When Maintenance is Results Expected I Components Needed When Maintenance is ' Performed General Missing or Any defect in the fence that permits Parts in place to provide Broken Parts easy entry to a facility. adequate security. , Erosion Erosion more than 4 inches high and No opening under the 12-18 inches wide permitting an fence that exceeds 4 opening under a fence. inches in height. Wire Fences Damaged Post out of plumb more than 6 inches. Post plumb to within 1- Parts 1/2 inches. Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence (including post, top Fence is aligned and rails) more than 1 foot out of design meets design standards. alignment. Missing or loose tension wire. Tension wire in place � and holding fabric. Extension arm missing, broken,or bent Extension arm in place out of shape more than 1 1/2 inches. with no bends larger than 3/4 inch. Deteriorated Part or parts that have a rusting or Structurally adequate Paint or scaling condition that has affected posts or parts with a Protective structural adequacy. uniform protective Coating coating. 19 COUGHLINPORTERLUNDEEN NO. 9-CONVEYANCE SYSTEMS (PIPES & DITCHES) Maintenance Defect Conditions When Maintenance is Results Expected Component Needed When Maintenance is Performed Pipes Sediment 8� Accumulated sediment that exceeds Pipe cleaned of all Debris 20%of the diameter of the pipe. sediment and debris. Vegetation Vegetation that reduces free All vegetation removed movement of water through pipes. so water flows freely through pipes. Damaged Protective coating is damaged; rust is Pipe repaired or causing more than 50%deterioration replaced. to any part of pipe. Any dent that decreases the cross Pipe repaired or section area of pipe by more than 20%. replaced. Open Ditches Trash & Debris Trash and debris exceeds 1 cubic foot Trash and debris cleared per 1,000 square feet of ditch and from ditches. slopes. Sediment Accumulated sediment that exceeds Ditch cleaned/flushed of 20%of the design depth. all sediment and debris so that it matches design. Vegetation Vegetation that reduces free Water flows freely movement of water through ditches. through ditches. Erosion See"Rain gardens"Standard No. 1 See"Rain gardens" Damage to Standard No. 1 Slopes Rock Lining Maintenance person can see native Replace rocks to design Out of Place or soil beneath the rock►ining. standards. Missing (If Applicable). Catch Basins See "Catch Basins: Standard No. 4 See"Catch Basins" ', Standard No. 4 Debris See"Debris Barriers"Standard No.S See"Debris Barriers" Barriers(e.g., Standard No. 5 �, Trash Rack) I THE HOTEL AT SOUTHPORT 2Q COUGHLINPORTERLUNDEEN , NO. 10-GROUNDS (LANDSCAPING) Maintenance Defect Conditions When Maintenance is Results Expected When Component Needed Maintenance is Performed General Weeds Weeds growing in more than 20%of the Weeds present in less (Nonpoisonous landscaped area (trees and shrubs than 5%of the ) only). landscaped area. Safety Hazard Any presence of poison ivy or other No poisonous vegetation poisonous vegetation. present in landscaped area. Trash or Litter Paper, cans, bottles, totaling more than Area clear of litter. 1 cubic foot within a landscaped area (trees and shrubs only)of 1,000 square feet. Trees and Damaged Limbs or parts of trees or shrubs that Trees and shrubs with Shrubs are split or broken which affect more less than 5%of total than 25% of the total foliage of the tree foliage with split or or shrub. broken limbs. Trees or shrubs that have been blown Tree or shrub in place down or knocked over. free of injury. Trees or shrubs which are not Tree or shrub in place adequately supported or are leaning and adequately over, causing exposure of the roots. supported; remove any dead or diseased trees. 21 COUGHLINPORTERLUNDEEN NO. 11 -ACCESS ROADS!EASEMENTS Maintenance Defect Condition When Maintenance is Results Expected When Component Needed Maintenance is PerFormed General Trash and Trash and debris exceeds 1 cubic foot Roadway free of debris Debris per 1,000 square feet i.e., trash and which could damage tires. debris would fill up one standards size garbage can. Blocked Debris which could damage vehicle tires Roadway free of debris Roadway (glass or metal). which could damage tires. Any obstruction which reduces Roadway overhead clear clearance above road surface to less to 14 feet high. than 14 feet. Any obstruction restricting the access to Obstruction removed to a 10 to 12 foot width for a distance of allow at least a 12 foot more than 12 feet or any point restricting access. access to less than a 10 foot width. Road Surface Settlement, When any surface defect exceeds 6 Road surface uniformly Potholes, Mush inches in depth and 6 square feet in smooth with no evidence Spots, Ruts area. In general, any surface defect of settlement, potholes, which hinders or prevents maintenance mush spots, or ruts. access. Vegetation in Weeds growing in the road surface that Road surface free of Road Surface are more than 6 inches tall and less than weeds taller than 2 6 inches tall and less than 6 inches apart inches. within a 400-square foot area. �� '� _ THE HOTEL AT SOUTHPOR i 22 COUGHLINPORTERLUNDEEN NO. 12-WATER QUALITY FACILITIES A.)Cartridge Filter Vault Maintenance Defect or Condition When Maintenance is Recommended Component Problem Needed Maintenance to Correct Problem Below Ground Sediment Sediment depth exceeds 0.25-inches. No sediment deposits Vault Accumulation which would impede on Media. permeability of the compost media. Sediment Sediment depth exceeds 6-inches in No sediment deposits in Accumulation first chamber. vault bottom of first in Vault chamber. Trash/Debris Trash and debris accumulated on Trash and debris Accumulation compost filter bed. removed from the compost filter bed. Sediment in When drain pipes, clean-outs, become Remove the accumulated Drain full with sediment and/or debris. material from the Pipes/Clean- facilities. Outs Below Ground Compost Media Drawdown of water through the media Replace media � Cartridge type takes longer than 1 hour, and/or cartridges. overflow occurs frequently. Short Circuiting Flows do not properly enter filter Replace filter cartridges. cartridges. Damaged Any part�f the pipes that are crushed, Pipe repaired and/or Pipes damaged due to corrosion and/or replaced. settlement. ' � Access Cover Cover cannot be opened, one person Cover repaired to proper �i Damaged/Not cannot open the cover, corrosion/ working specifications or I Working deformation of cover. replaced. Vault Structure Cracks wider than 1/2-inch and any Vault replaced or Includes evidence of soil particles entering the repaired to design Cracks in Wall, structure through the cracks, or specificati�ns. Bottom, maintenance/inspection personnel Damage to determines that the vault is not Frame and/or structurally sound. Top Slab 23 COUGHLINPORTERLUNDEEN Cracks wider than 1/2-inch at the joint No cracks more than 1l4- of any inleUoutlet pipe or any evidence inch wide at the joint of of soil particles entering the vault the inleU outlet pipe. through the walls. Baffles Baffles corr�ding, cracking warping, Repair or replace baffles and/or showing signs of failure as to specification. determined by maintenance/inspecti�n person. Access Ladder Ladder is corroded or deteriorated, not Ladder replaced or Damaged functioning properly, missing rungs, repaired and meets cracks, and misaligned. specifications, and is safe to use as determined by inspection personnel. 24 COUGHLINPORTERLUNDEEN Figures Figure 1 —TIR Worksheet Figure 2—Parcel Conditions Figure 3—Site Location Figure 4—Proposed Conditions Figure 5—Drainage Basin Map Figure 6— Flow Control Map Figure 7—King County iMAP- Floodplain Figure 8—City of Renton Soil Survey Map Figure 9— Drainage Complaints Map ! � II I � i I � ,I � ��I E �� - T��_ =� _ 2 5 I Figu re I - TI R Worksheet King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND PROJECT ENGINEER DESCRIPTION Project Owner: Project Name: SECO Develo ment South ort Hotel Address: Location 1083 Lake Washington Blvd. Suite 50 Renton,WA 98056 Phone: Township: 23N 425 282-5833 Range: 5E Project Engineer: Section: 8 Bart Balko, P.E. Com an : Cou hlin Porter Lundeen Address/Phone: 801 Second Avenue, Ste 900 Seattle,WA 98104 206 343-0460 Part 3 TYPE OF PERMIT Part 4 OTHER REVIEWS AND PERMITS APPLICATION ❑ Subdivison ❑ DFW HPA ❑ Shoreline Management ❑ Short Subdivision ❑ COE 404 ❑ Rockery ❑ Grading ❑ DOE Dam Safety ❑ Structural Vaults ❑ Commercial ❑ FEMA Floodplain ❑ Other � Other: SPR ❑ COE Wetlands � Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community: !� Green River Valle ' Drainage Basin: '� Lake Washin ton East Draina e Basin I Part 6 SITE CHARACTERISTICS � i ❑ River ❑ Floodplain ❑ Stream ❑ Wetlands ❑ Critical Stream Reach ❑ Seeps/Springs ❑ Depressions/Swales ❑ High Groundwater Table � Lake Washington ❑ Groundwater Recharge ❑ Steep Slopes ❑ Other Part 7 SOILS Soil Type Slopes Erosion Potential Erosive Velcoties Very loose to medium 0-5% dense, non-silty to silty Sand Very soft to medium stiff and stiff Silt and Clay Soft to medium stiff and stiff Silt ❑ Additional Sheets Attached Part 8 DEVELOPMENT LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT Ch.4— Downstream Analysis ❑ Additional Sheets Attached Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION ❑ Sedimentation Facilities � Stabilize Exposed Surtace � Stabilized Construction Entrance � Remove and Restore Temporary ESC � Perimeter Runoff Control Facilities � Clearing and Graing Restrictions � Clean and Remove All Silt and Debris � Cover Practices � Ensure Operation of Permanent Facilities � Construction Sequence ❑ Flag Limits of SAO and open space preservation areas ❑ Other ❑ Other Part 10 SURFACE WATER SYSTEM ❑ Grass Lined ❑ Tank ❑ Infiltration Method of Analysis Channel � Vault ❑ Depression � Pipe System ❑ Energy Dissapator ❑ Flow Dispersal Compensation/Mitigati ❑ Open Channel � Wetland ❑ Waiver on of Eliminated Site ❑ Dry Pond Storage ❑ Stream ❑ Regional ❑ Wet Pond Detention Brief Description of System Operation A wet vault will be used to provide Basic water quality treatment. Facility Related Site Limitations Reference Facility Limitation Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTSlTRACTS ❑ Cast in Place Vault ❑ Drainage Easement � Retaining Wall ❑ Access Easement ❑ Rockery> 4' High ❑ Native Growth Protection Easement ❑ Structural on Steep Slope ❑ Tract ❑ Other ❑ Other Part 13 SIGNATURE OF PROFESSIONAL ENGINEER I or a civil engineer under my supervision my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attachments. To the best of my knowledge the information provided here is accurate. Si ned/Date 4/22/2014 King CountyDistricts arxl Deeelopment Conditions for parcel number 0623059216 � KingCounty Figure 2 - Parcel Conditions King County Districts and Development Conditions for parcel 0823059216 Parcel 0823059216 Drainage East Lake Washington-Renton and Water- '�� '�� ; number Basin Lake Washington � i '` . Address Not Watershed Cedar River/Lake Washinqton �, ' �� _ -_ ,� Available ��^JRIA Cedar-Sammamish(8) �� . r` Jurisdiction Renton PLSS NW -8 -23 -5 � `y Zipcode 98056 Latitude 47.50291 �� '" ' � ` ___ - ------ _ � Kroll Map 309 and 319 Longitude -122.20596 � page Thomas 626 Guide > �; _. page '- Electoral Districts `�'otin�a �Jistr�ct RNT37-0991 Fire district dces not apply Kinq Countv Coun��:�l district District 5, Dave Waterdistrict does not apply Upthegrove Sewer district does not apply (206)296-1005 Q Water&Sewer district dces not apply Congressional district 9 Parks &Recreation does not apply ' � Legislative district 37 district School district Renton#403 Hospital district Public Hospital District No. 1 Seattle school board district dces not apply(not in Rural library district Rural King County Library Seattle) System flictrirtf:niirfalartnralrlictri�t CnuthAac4 ___ �-_:�._� � __a..� _ ��_ King County planning and critical areas designations Ki��a Countyzor.ing NA,check with Po,ential annexation area does not apply jurisdiction Rural town? No Development conditions None 1,ti�ater service plannin area does not apply Comprehensive Plan does not apply Roads MPS zone 111 and 112 Urban Growth Area Urban Transportation Concurrency dces not apply CommunityServiceArea dcesnotapply hAanagement Communiry Planninq Area C�een River Valley Forest Production district? No Coal mine hazards? None mapped Agriculturat Production district? No Erosion hazards? None mapped Critical aUuifer recharqe area? None mapped Landslide hazards? None mapped 100-yearflood plain? None mapped Seismic hazards? None mapped WeUands at this parcel? None mapped '�"�;tl�in tne Tacoma SmelterPlume? Non-Detectto20.0 ppm Estlmated Arsenlc Concentretlon In Soil This report was generated on 4/22/2014 1:55:30 PM Contact us at qiscenter(cr kinqcounty_qov. O 2010 King County http:/Mvvw6.la ng county.g ov�KC GISRepcxts/dd_report�ri nt.asp�C?PI N=0823059216 1/1 4J24l2014 King CountyDistricts and Deeeloprr�ent Conditions for parcel number 0523059075 � King County King County Districts and Development Conditions for parcel 0523059075 . �-�.� _ �'arcel 0523059075 Drainage East Lake Washington-Renton and Water - � � ,�; number Basin Lake Washington � �;. Address Not Watershed Cedar River 1 Lake Washinqton ,r��► � Available �tiRIA Cedar-Sammamish(8) _ �:� .� Jurisdiction Renton PLSS NW -8-23-5 �=- ` __ 4 �=� Zipcode 98056 Latitude 47.50269 � Kroll Map 309 and319 L�ngitude -122.20562 page Thomas 626 Guide page Electoral Districts Vc:',r�� is:r'.::: RNT37-0991 Fire district does notapply King CountvCouncil district District 5,Dave Water district does not apply Upthegrove Sewer district does not apply (206)296-1005 � Water&Sewer district does not apply ongressional district 9 Parks &Recreation dces not apply _egislative district 37 district School district Renton#403 Hospital district Public Hospital District No. 1 Seattle school board district does not apply(not in Rural librarydistrict Rural King County Library Seattle) System flictrirtrniirfalartnral rlictrirt Sn��thoa�__._____ -r_:�._� � __a_n .�_ King County planning and critical areas designations KingCour�.�zon+nq NA,checkwith Po?e��tiala��ne�tionarea dcesnotapply jurisdiction Rural to��vn? No Development conditions None Water senrice plannin�area dces not apply Comprehensive Plan does not apply Roads f�1PS zcne 111 and 112 Urban Growth Area Urban Transportation Concurrency dces not apply CommunitvService Area dces not apply P�1ana ement CommunityPlanningArea GreenRiverValley ForestProductiondistrict? No Coal mine hazards? None mapped Agricultural Production district? No , Erosion hazards? None mapped Crit�cal aquifer recharqe area? None mapped ,, Landslide hazards? None mapped 100-y�earflood plain? None mapped ', Seismic hazards? None mapped Wetlands atthis parcel? None mapped , �i'd!thin the Tacoma SmelterPlume? Non-Detectto20.0 ppm li Estima[ed Arsenlc Goncentration in Soil This report was generated on 4124/2014 12:03:31 PM Contactus at gisrenterrakinqcc.::,__-;�_. 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M� , . .v . !' +.wa y, , �, a�� w q,�,��4..� � ' � '1 r_�..,, � . �ti �.'1��-'1...��Y w�� '^Y''S'��,'� 7 ' iF - "�� 'ia �� ' �°f" '4�� 1� �. ;# �+wX � � n T O ��. w'.. . . �..�'.��'.. � t�� .!'a� .,.�_ rr�L ��.i .��. � '�� _ . `'t. �r_ ,.�--IiE.�`�. .1�...., s.LiYR ..-'3 Z � � Table 2-Developed Site Conditions Area Breakdown Land Cover Area Description Impervious Area 7.15 acres Building roof, parking areas, drive aisles,fire lane Pervious& Landscape 0.84 acres Associated landscaping, undisturbed areas Total Project Area 7.99 acres Total site area Percentage of Impervious Area 89% Lake Washington Existing Drainage Existing Outfall to Tunnel - Discharge to Lake Washington Lake Washington , ! ^ _ .=_�. ._-- - - ' � � ,_ _ _ _ __._. . �..� �-'-- --- � ' ' _. _ __ , r__ � �- r_...— -_ , _--�:,---- =-- _•_- -� I , � ' -- - - � , ; , , . , y , . � I _ _ _ . .. � _ „ ° .,� --j�� k_ '_ — _ b '�� . . , �, . 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(treated by existing wetv t) i� � ' ' ` ading A ea �_ � . --�`� Existing wet vault (treated,by • " _ :; ' �, . /�/ � installed w�th Phase 1 Storm,Filter / / / cartriSlges) / / ��` C�@V@�Opfll2flt t� , ;� , . _ - _ , I � •� � � � . _ _ " — - Treated , � y l � � � __ . _ _ . . . . . . . . . . . � �; : , discharge ] � - ------------------------------ -- . ` . _ �'ti"\ ] ; l� �- - - - -�- - - - -� � ' � . ` �� Wet vault�� I � , . � � �� . . � `� ` " high flow � I � �. ,. � discharge I ' . . � w ` , • . . � _ � T : ; '�'� � \ :.� �� C �� I � � � - ' ' i Surface ng Lot � Pum ed � ed in�existing vault) p I nn i n Co ect o � � w , i � i � � , � ______ , , to existing i ' -�� storm stub � I � - - - - - - ��.� '�� , � ;� : �- � �---- --rt- ---- - -'--- --- ---- --- --- - -- ---------- ---:- � � T ; + ! � � , � r ' , � PSE Upstream �,� � __ Drainage Bypass ., ___ � � � , - - - - �= - - - - - - - - - - - ,.. 7 ~�_ -. _... ' .-� - -. .._ __ ; 1 l 1 ! 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This document is not intended fo��se as a survey product.King County shall not be IiaWe for any general,special,indirect,incidental,or consequentlal s � damages including,bu[rat limited to,bst revenues or lost profits resultmg from the use a misuse ot the information contained on this map.Any sale of Kmg County this map or information on this map is prohibited except by written pertnissan of King County. pate:10l10/2013 Source:IGng County iMAP-Hydrographic In(ormaUon(h1�J/www.metrokc.gov/GI�MAP) Figure 8 - Soil Survey " �ap r � I � i , , , , ,�n��'�l- � �•-• �� . ��'Sk �� '� �♦ � � ��, Bh K C:� . I �' �PD �� •�. Ir � � l \ I � , i nq,PD ,,...,.I A No � �-..` . � �, �� E�cR�e � : « � . � RdE � � n�� +' ��'. � >� � t_ ,,-�. AkF � � •• � �_.•�- :-�,pY,�. :� —•,... ..._. ��■ � ~ In/� .. •. �vC`�ti�.rn�o:�ava�� '..l�gD •��..ua., : 11 AkF� �EvB Bh EvC �v8 r`�F'vd' �EvD � �t.....� A9� RdC r�``.,,,. 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TWO p� Seattle � � � Project Site - s� z Y " ` No Drainage Complaints ,,��M� � p = � o � ''-, — wE,en,sr., �` � Z �' < ' c < E i7T�y �' W� � a � !�' �� NE 17TN ST � p e � � � - , �� `, � � � NE/7M R _- . ---� �' ' _- i' �I � _ ��..- �- �. __ :l� IIE 1TM ST �..- �D�7225 • NkP�KpR J� T �� - , O W�� i� �O Y 2� � 101'M � �' � ir 'i �Z � NE/QTM ST � � _r� = D96779��, , � NE�� (�, W ; � ' '� N tOTH Pl � p s �j � � : � �i`I � Z �i NE 5TM ST � T z _ �� , �r ? i�I 9.c � �� ; � � , � � ' �� tis� $ N�►,� �, Renton g � �m��r � �'''�'R � � I � Z �'�,j t � _ � s � � � ��,, �._ ..Z._z ��'w' �� '� ,� , �en�cT . �I 1'Sti� J � � 2 � ';ME 5TM 5r � � 4 yC ' � � � `� � � NE 4TH ST � � � � �� N�� NE4TM5T � t � _ _ __-=_-_- . � � 1'�� ' N 3RD ST � ��U020 ` i '� �� .� � _�,;`�' 1� Na1D ST � N�3��• � NE210 PLI'�.3 �' - - ,¢l, NE bt�SY � �~ � ST�� . � Legend �t County Bou�ary � King Courky VYater Resource ,�� S�p � InveMory Anas ��Gt x Nou�in Puks � p S 3RD 5T � _ � 1 Drainaga Swdles � Kinp County Drainage Basins x Y al �t=--- Naighbwtaod Drainage ./ Incorporated Area � S diH ST ,u �'' '��+. � Projacts !`" - 4 ��i Streets i �a , S�� Z � _ � Regia�alSLormwalarFacilides M,�,,.,y N � � -'�_= RQsidaMlal SEormwater � �� y � Facilities SY� 7TH ST � Y �p �� C«mrroial Slormwalar �' La ak s and Large Rivers � ♦ Facilities �y�pY'�'�P 9� Streams � S � q Highways � prainage Complaints �, �CI200BKmqCounty 5�'1''�'� 0 2541ft The in/ortnation inGuded on this map has been cort�piled by King County staft from a variety of sources and is subjed W change without notice.King County makes no representations or warranties,express or implied,as ro accuraq,completeness,dmeliness,a righLs to the use of such information. This dowment is not intended ta use as a suney producl.King Counry shall not be liable for any general,spedal,indirect,incidental,or consequential a � damages induding,but not limited to,lost revenues or bst profits resultmg from the use a rtususe of the infortnafiom m�tained on tliis map.My sale of K�ng County this map or information on this map is prohibited except by written pertnisaon of King County. Date:10/10/2013 Source:King County iMAP-S[orm�valer(hllp:/hvww.metrokc.gov/GIS/iMAP) COUGHLINPORTERLUNDEEN Appendix A Engineering Calculations East StormFilter Calcuations West StormFilter Calcuations Parking Lot Wetvault Sizing Calcuations 2s �/,!��' j ; j ;'" P RTER /�� COUGHLIN O LUNDEEN / ,, j / /� / Engineering Calculations CONVEYANCE ANALYSIS / i � ' , � . ___.__- --L-- a .��r. — - ��. _ .._ . i BASIN ' G 3 t_' ;,�...#, ..,.. :� � ;, � t � ,:� ��• � ;�� , - � r :�� i - � . � �� BASIN ��' u ;: ._� �� : F � a,._ ,�. i � � _ sa-� , ;- . BASIN ��/r C� : =��-� -i � :� _ A4 =;, � -�..� ,, .��.. � ,.W� .,..�.. . � �..c . . — . . ; .�,�n__ : �__», : � q..�__._ , w i, — � �� , i. ; � . I-�- ��- _ _ _ ��' , _ � � �� t BASIN ' ' :. 1'' 'I � �� , � - C4 - � _\;" �Y.__ -�. � a-� . . �. � � , ._ I, � � . . , - — —' ; `" � �%;. j, � — --- t,-- � �• �_ I_ � 1- F �,m��\ �. \�" \ �a+�ea�... .I I r <� \``'�. (X �� B A S I N -`"�' � '\.:, � {.`� � B3 _� � � �� '� �'_� �_. I r � \— , � �, �::.--� � � � � .� - � - �— --_ -___ .�.. 4-� �1 T- I -/.-, � 11� �:�" ,'t,i . , � I � �� `; �, � �� i � �, � — _--� � �.:; / � � .,�'i �— ='�� — — '�"-= —�+. B A S I N � � � .�� s� \: � � �� , ; �' z�. � � .y �� (; � / '� ��i C, n � ' �. � � l ��y---T-. --- — ----- -- --- ---�_=� --- -------\--- ---._ r� �, . I' , � T � - � . . �� .�=� B A S I N �y :� � � � B5 p;�= � ,� , . � — � i � _� - -� r /, Y , �� i I : \ ..� I , ... �.- ' �` �------- --- -- ---- -- .�.,e / ; _--__ i__ - , , � � --�� — _ .. r - :.��. � _ �.�,_ �_— �-:. , —�—.a.:- — -,..-.. — � .,-- _° , � � __ ___ . . ? � _ .-� I I I J � I !,� i•� � � , ----------- =------- -------r-------- -------------- --- - _. -- - ------------ ---� � , .�_:.. BASIN ' -- ;. ,— --- i = • " � B7 � : � : � !: f k�:� � . . �_ - � . �� , 1" = 100' COUGHLINPORTERLUNDEEN C O N V E Y A N C E B A S I N M A P SOUTHPORT HOTEL West Sub-basin - VVest Southport Hotel Firelane including partiaf roof collection area Catch Basin Sub-basin Areas Sub- Total Composite Impervious Pervious Basin Area� C Value Area Area (Acres) (Sq. Ft), C=0.90 (Sq. F�), C=0.25 ROOF AREA 0.51 0.90 22055 0 CB#Jl 0.00 0.00 0 0 CB#J1A 0.03 0.90 1266 0 CB#J2 0.03 0.90 1488 0 CB#J3 0.04 0.40 1646 0 OUTLET 0.00 0.00 0 0 Totals 0.bI 26456 0 Notes: �These sub-basin azeas are based on developed site conditions. i Southport Hotel Conveyance Analysis Renton,WA 1 4!9,�2015 100-Year Backwater Backwater Analysis Table Msnninea Coefficient o.02� Southport Hotel Stocm Eveat Renan Period 100 Proposed Site Conditions to Vault Location Q L Pipe T'YP Oatlet Inlet Barrd Barrel Velocity Fseel Critical TR' Friction HGL Enuy Eutry Ezit Ouflet Hesdwater In1N Approach Bend Bead daneI.oss Janction Headwzter Rim FJev. O.K.? Down�tream U stream (cfe) (F'T) Diam(ia). n Elev Elev Area Velocity Head Check Depth Elev Losa Elev Ccet L099 Loss Control Depth Control Herd Caeffident Lose Coeffident Loss Elevatlon ma...e Outlet ROOFAREA 1.44 7 12 0.024 18.30 ]8.40 0.785 L836 0.052 1.00 0.51 17.70 0.036 19.40 0.50� 0.03 0.05 14.46 0.56 18.96 -0.OS 0 0.00 0.00 0.00 19.43 21.44 2.01 �s ROOFAREA CB#72 137 20 12 0.024 I8.40 18.b0 0785 1]40 0.047 1.00 0.49 19.15 0.099 19.60 0.50 4.02 0.05 ]4.h7 0.54 19.14 -0.OS L.73 0.06 0.10 � 0.17 19.86 2134 1.48 �s CB#J2 CB#J3 0.09 66 8 0.024 18.60 19.31 0349 0.271 0.001 I.00 014 19.86 0.014 19.98 OSO 0.00 D.00 7��R 022 19.46 0.00 Q 0.00 0.10 0.03 20.00 21.48 1.48 � ROOF AREA CS#J1A 0.07 29 8 0.024 IB.�O 18.69 0349 0.209 0.001 1.00 0.12 18.79 0.004 1936 D.50 0.00 0.00 19.16 O.19 18.82 0.00 1.23 0.00 0.10 0.02 1938 21.48 2.10 es CH#R Roof Drain Connxrion 0.73 70 8 0.024 i8.b0 18.65 0.349 2.104 0.069 t.00 0.40 19.14 0.871 20.01 0.50 0.03 0.07 ?0.11 0.69 19.I1 -0.07 1.23 0.08 0.10 0.21 20.34 Z1.50 1.16 iI Southport Hotel Backwater Analysis- 100-Year Renton, WA 4/9/2015 100-Year Conveyance Location Sub Area C C'A Sum Tc I Q(R) Pipe Typ. Slope Q(F) V V L Tt d/D Q� Basin C'A (c.£s.) (pipe (pipe (at Qa From To Number (acres) (min.) (in.) Manning,s„n�• (ft.iR) full) full) Q(R)) (ftJ (min.) (%) (%) Roof Drain Connection CB#J2 N/A 0.51 0.90 0.46 0.46 15.0 1.61 0.73 8 0.028 Z.00% 0.80 2.29 2.35 4 0.0 84.00% 91.8% CB#J1A ROOF r�REA CB#J1A 0.03 0.90 0.03 0.03 63 2.78 0.07 8 0.028 1.00% 0.56 1.60 0.87 29 0.6 29.00% 13.0% CB#J3 CB#d2 CB#J3 0.04 0.90 0.03 0.03 63 2.78 0.04 8 0.028 1.00% 0.56 1.60 0.94 66 1.2 33.00% 16.9% CB#12 ROOF AREA CB#J2 0.03 0.90 0.03 �.55 7.5 2.50 1.37 12 0.028 1.00% 1.66 2.11 2.11 20 0.2 77.00% 823% ROOF AREA Ouflet ROOF AREA Q.51 0.90 0.46 0.55 6.9 2.64 i.44 12 0.028 2.00% 235 2.99 2J7 7 0.0 63.00% 61.4% Project_Southport Hotel R= 1001+r P(R� 3.40 Calcs by. CJB Job No:C14-0507-01 Locarion:Renton WA Date: 4/9/2015 Southport Hotel Renton, WA Conveyance:�nalysis- 100 Year 4/9/2015 25-Year Backwater Backwater Analysis Table Monnings Coefficient o.oza Southport Hotel � Storm fivrnt Renun Paiod 25 Proposed Site CondiQone to VaWt Location Q L Pipe 1'YP Outlet Inlet Barnl Barrel Veloeiry Ezcel Crltical TW Friction HGL Enky Entry Ezlt Oatlet Headwater Inlet Approach Bend Bend JnncLoee Junctlon Headwater Rim Elev. O.K.7 Dowustream Upatream (cts) (FI') Diam(in). n Elev IIev Area Velocity Head Check Depth Elev Lass Elev Ccef Loss Loas Control Depth Control Head Coeffieient Loss Coeffcient Loss Elevafion n;a�,� OutlM ROOF AREA 1.41 7 12 0.024 1830 18.40 0.765 1.799 0.050 1.00 0.50 17.70 0.034 19.40 0.50 0.03 0.05 19.4h 0.55 18.95 -0.05 0 0.00 0.00 0.00 19.43 21.44 2.01 es ROOF AREA CB#J2 134 20 12 0.024 18.40 18.60 0.785 1J01 0.045 1.00 0.49 19.14 0.095 19.60 0.50 0.02 0.04 19.57 0.53 19.13 -0.04 1_]3 0.06 0.10 0.17 19.85 2134 1.49 es CH#]2 CB#)3 0.09 66 8 0.024 ]8.60 1931 0349 0.266 0.001 1.00 0.14 19.85 0.013 1999 O50 0.00 0.00 799x 022 19.46 0.00 0 0.00 0.30 0.03 20.00 21.48 1.48 es ROOFAREA CB#71A 0.07 29 8 0.024 18.40 IS.b9 0349 0205 0.001 1.00 0.12 18]9 0.003 ]936 0.50 0.00 0.00 ]9 a6 0.19 18.82 0.00 7.23 0.00 0.10 0.02 1938 21.48 2.10 CB#J2 Roof Dtain Cofficetion 0.71 70 B 0.024 18.60 I8.65 0349 2.031 OA64 1.00 0.40 19.13 0.812 19.94 030 0.03 0.06 Zu.04 0.6) 19.10 -0.06 123 0.08 0.10 0.20 20.26 2130 1.24 es Southport Ilotel Bacicwater Analysis-ZS-�'ear Renton,VdA 4/9/2015 Southport Hotel Catch Basin Sub-basin Areas Sub- Total Composite Impervious Pervious Basin Area� C Value Area Area (Acres) (Sq. F�), C=0.90 (Sq. Ft.), C=0.25 CB#B9 0.13 0.82 4836 661 CB#B8 0.13 0.77 4398 1151 CB# B7 0.17 0.76 5677 1563 CB#B6 0.12 0.76 4087 1074 CB#BS 0.12 0.85 4918 408 CB#BSa 033 0.90 14238 0 CB#B4 0.18 0.88 7817 213 CB#B3 0.12 0.85 4680 416 CB#B2 0.08 0.74 ?548 866 CB#B1 0.07 0.86 ?752 161 CB#A4 0.14 0.90 6114 0 CB#A3 0.14 0.87 5633 308 CB#A2 0.00 0 0 CB#A1 (Pumped) 0.00 0 0 OUTLET 0.00 0 0 Totals 1.71 67698 6821 1.55 0.16 Notes: �7"hese sub-basin areas are based on developed site conditions. Southport Hotel Conveyance Analysis Renton,WA 1 3/3/2015 25-Year Conveyance '�, Location Sub Area C C*A Sum Tc [ Q(R) Pipe Typ. Slope Q(F) V V L Tt diD Q� ' Basin C'�A (c.f.s.) (p�pe (P�pe (at QF From To Number (acres) (min.) (in.) Manning's"n" (ft./ft.) full) full) Q(R)) (ft.) (min.) (%) (%) CB,�B9 CB#B8 CB#B9 0.13 0.82 0.10 0.10 63 2.73 0.28 8 0.028 0.50% 0.40 L15 1.09 175 2.7 69.50% 70.9% CB#B8 CB#B7 CB#B8 0.13 0.77 0.10 0.20 9.0 2.17 0.50 12 0.028 0.50% 1.17 1.49 1.23 89 1.2 51.00% 42.3% CB#B7 CB#B6 CB#B7 0.17 0.76 0.13 033 10.2 2.00 0.75 12 0.028 0.50% 1.17 1.49 138 30 0.4 65.00% 64.0% CB#B6 CB#BS CB#B6 0.12 0.76 0.09 0.42 10.5 196 p,93 12 0.028 0.50% 1.17 1.49 1.47 48 0.5 75.00% 79.1% CB#BSa CB#BS CB#BSa 033 0.90 0.29 0.71 63 2.73 0.80 8 0.028 0.50% 0.40 1.15 230 74 0.5 99.90% 201.1% CB#BS CB#B4 CB#BS 0.12 0.85 0.10 0.82 11.1 1.89 ].93 15 0.028 0.50% 2.13 1.74 1.78 101 0.9 82.50% 90.5% CB'�B4 CB#B3 CB#B4 0.18 0.88 0.16 0.98 12.0 1.80 2.22 15 0.028 0.50% 2.13 1.74 1.81 108 1.0 99.90% 104.2% CB#B3 CB#S2 CB#B3 012 0.85 0.10 1.08 13A 1.71 239 15 0.028 0.50% 2.13 1.74 1.95 85 U.7 99.90% 112.1% CB#B2 CB#Bl CB#B2 0.08 0.74 0.06 1.14 13.7 1.65 2.48 15 0.028 0.50% 2.13 1.74 2.02 48 0.4 99.90% 116.6% CB#B1 CB#A2 CB#B1 0.07 0.86 0.06 1.19 14.1 1.62 2.58 15 0.028 0.50% 2.13 1.74 2.10 21 0.2 99.90% 121.0% CB#A4 CB#A3 CB#A4 0.14 0.90 0.13 0.13 63 2.73 0.35 8 0.028 1.00% 0.56 1.60 1.46 60 0.7 64.00% 61.7% CB#A3 CB#A2 CB#A3 0.14 0.87 0.12 0.24 7.0 2.56 0.6� 8 0.028 10.00% 1.78 5.10 4.02 8 0.0 47.00% 36.4% ' CB#A2 CB#A1(Pum ed) CB#A2 0.00 0.00 0.00 1.� 143 1.60 3.22 15 0.028 2.00% 4.25 3.46 336 4 0.0 73.00% 75.9% CB#A1 Pum ed) Outlet CB#A1(Pum ed) 0.00 0.00 0.00 1.44 14.3 1.60 3.22 15 0.028 54.20% 22.14 18.04 10.18 12 �.0 30.50% 14.6% Project: ut port ote R= 2� P{Rp ?.� Calcs by: CJB Job No:C14-0507-01 Location: Renton WA Date: 3l'3;'2015 Southport Hotel � Renton. 1�'A Com-eyance Analysis - 25 Year 3/3/201� , 25-Year Backwater Backwater Analysis Table Mannings Coe(ficient o.o�-� Southport Hotel Srorm Event Remm Period ?5 Proposed Site Conditions to Vault Location Q L Pipe TYP Outlet Inlet Barrel Barrel �elocih� Excel Crifical T�i' FricHon HGL Entry Entry Euit Outlet Headwater Inlet Approach Bend Bend Juuc Loss Juncfion Headµ•ater Rim Elev. O.K.? Downstream Upstream (cfs) (FT) Diam(in). n Elev Ele�• Area Velocitv Head Check De th Elev Loss Elev Coef Loss Loss Control De th Control Head Coefficient Loss Coefficient Loss Elevation DiRerence OuHet CB#A1 Pum ed 3.22 12 1= 0.024 12.00 18.00 1.?27 2b27 0.107 1.00 0.72 1?.99 0.101 19.25 O.SO 0.05 0.11 1Q.11 0.90 19.12 -0.11 0 UIIO 0.00 0.00 1930 21.00 IJO es CB#Al(Pumed) CB#A2 3.22 4 l� 0.024 12.50 12.75 1?27 2.627 0.107 1.00 0.72 ]3.49 0.034 14.00 0.50 0.05 O.II 14.16 0.68 13.60 -0.11 0 Ii1Xl 0.00 0.00 14.05 21.50 7.45 •es CB�A2 CBX A3 O.b� R 8 0.024 18.00 18.80 U349 1.8�5 0.053 1.00 038 14.0� 0.077 19.4? 0.50 0.03 0.05 19.ij 0.68 19.26 -0.OS 0 u IHI 0.00 0.00 19.49 21.43 1.94 ves CB#A3 CB�A4 03� 60 R 0.024 (S.SO 19.40 0.;49 0.989 0.015 1.00 0.?7 19.49 0.165 20A? 0.50 0.01 0.02 20.09 0.44 19.69 -0AZ 0 ��.00 0.10 0.10 20.1? 21.00 0.83 ves CBt�A2 CBttB1 2.58 21 15 0.024 15.85 ]6.10 1?27 2.099 0.068 1.00 O.b3 16.80 0.113 ]735 0.50 0.03 0.07 17.45 0.57 16.81 -0.07 133 0.09 0.10 0.21 17.64 21.43 3J4 ves CB#BI CBuBZ 2.48 48 15 OA24 16.10 16.3� I.'_27 2.023 0.064 1.00 0.63 17.69 0.240 17.92 0.50 0.03 0.06 IR.02 0.55 17.04 -0.OG 0.1 0.01 0.00 0.00 U.96 2L�4 3.58 es CB#82 CBu63 2.39 SS 15 0.024 1635 16.7� I.?„ 1.946 0.059 1.00 0.62 17.96 0392 ]836 0.50 0.03 0.06 1R.44 0.54 17.42 -0A6 0 IL00 0.00 0.00 IR.3R 2150 3.12 es CBX B3 CBu B4 2.22 134 15 0.024 16.75 17.46 1.?�7 1.808 O.OS1 L00 0.59 1838 0.534 18.92 0.50 0.03 0.05 IR.49 0.52 18.10 -0.OS 0 IL00 0.00 0.00 18.94 21.50 2.56 es CB�B4 CB�B� 1.93 75 1� 0.024 17.46 17.79 1.='_,' L570 0.038 I.00 0.55 18.94 0.225 19.17 0.50 0.02 0.04 I4.'_3 0.47 1838 -0.04 0 O DU 0.00 0.00 19.19 21.50 231 es CBR BS CB�r B=a 0.80 72 1? 0.024 17.79 19.00 0.%35 1.024 0.016 1.00 038 19.19 O.123 20.00 0.50 0.01 0.02 =0.0'_ 0.40 19.40 -0.02 0 �:00 0.00 0.00 20.01 21.50 1.49 es CB#BS CBR B6 0.93 70 12 0.024 17J9 18.13 OJS� 1.179 OA22 1.00 0.40 19.19 0.159 I9.35 0.50 0.01 0.02 1938 0.43 18.56 -0A2 0 0.00 0.00 0.00 1936 21.50 2.14 es CB#B6 CBR B' 0.75 l l3 12 0.024 18.13 1818 0.'8� 0953 0.01� 1.00 0.36 1936 0.168 I9.53 0.50 0.01 OAl 19.5� 038 18.66 -0.Ol 0.36 u.01 0.00 0.00 1954 21.83 2.29 es CB�?B? CB?l BR 0.5� 145 12 0.024 18.28 18.72 0.78> 0.631 0.006 1.00 029 19.�� 0.095 19.72 0.50 0.00 0.01 I�.'3 030 19.02 -0.Ol 036 C.00 0.00 0.00 19.73 21.10 13' ves CBR B8 CB#B9 0.28 ]OS 12 0.024 18.72 19.60 0.78� 0.361 0.00? 1.00 022 19.?3 OA23 20.60 0.50 0.00 0.00 'ii hii p23 Iq,g3 0.00 0 0.00 0.00 0.00 20.60 21.I0 0.50 ves Southport Hotel F3ack��ater Analysis-2ti-Year Renton, WA 3/3/2015 100-Year Conveyance Location Sub Area C C*A Sum Tc I Q(R) Pipe Typ. Slope Q(F) V V L Tt d/D Q� Basin C*A (c.f.s.) (pipe (pipe (at QF From To Number (acres) (min.) (in.) Manning's"n° (ft./ft.) full) full) Q(R)) (ft.) (min.) (°/a) (%) CB#B9 CB#B8 CB#B9 0.13 0.82 0.10 0.10 6.3 3.19 03? 12 0.028 0.50°/a 1.17 1.49 L07 175 2.7 41.50% 28.3% CB#B8 CB#B7 CB#B8 0.13 0.77 0.10 0.20 9.0 2.55 O.SR 12 0.028 0.50% 1.17 1.49 1.27 89 1.2 56.50% 49.5% CB#B7 CB#B6 CB#B7 0.17 0.76 0.13 033 10.2 2.36 0.8F 12 0.028 0.50% 1.17 1.49 L45 30 03 72.00% 75.0% CB#B6 CB#BS CB#B6 0.12 0.76 0.09 0.42 10.5 231 1.0) 12 0.028 0.50% 1.17 1.49 L53 48 0.5 84.50% 92.9% CB#BSa CB#BS CB#BSa 033 0.90 0.29 0.71 6.3 3.19 0.94 12 0.028 0.50% 1.17 1.49 L47 74 0.8 76.00% 803% CB#BS CB#B4 CB#BS 0.12 0.85 0.10 0.82 111 2.24 2.2G 15 0.028 0.50% 2.13 1.74 1.84 101 0.9 99.90% 106.0% CB#B4 CB#B3 CB#B4 0.18 0.88 0.16 0.98 12.0 2.13 2.61 15 0.028 0.50% 2.13 1.74 2.12 108 0.8 99.90% 1223% CB#B3 CB#B2 CB#B3 0.12 0.85 0.10 1.08 12.8 2.04 2.81 15 0.028 0.50% 213 1.74 2.29 RS 0.6 99.90% 131.8% CB#B2 CB#Bl CB#B2 0.08 0.74 0.06 1.14 13.4 1.98 2.92 15 0.028 0.50% 2.13 1.74 2.38 48 0.3 99.90% 137.2% CB#B 1 CB#A2 CB#B l 0.07 0.86 0.06 I.19 13.8 1.95 3.0 i 15 0.028 0.50% 2.13 1.74 2.47 21 0.1 99.90% 142.5% CB#A4 CB#A3 CB#A4 0.]4 0.90 0.13 0.13 6.3 3.19 0.40 8 0.028 1.00% 0.56 1.60 1.55 60 0.6 70.00% 72.0% CB#A3 CB#A2 CB#A3 0.14 0.87 0.12 0.24 6.9 3.00 0.7fi 8 0.028 10.00% 1.78 5.10 4.13 8 0.0 52.00% 42.6% CB#A2 CB#A1 (Pum ed) CBk A2 0.00 0.00 0.00 1.44 13.9 1.94 3.74 15 0.028 2.00% 4.25 3.46 3.52 4 0.0 82.00% 89.2% CB#A1 Pum ed) Outlet #A1 Pum 0.00 0.00 0.00 1.44 139 1.94 3.7) 15 OA28 54.20% 22.14 18.04 10.74 12 0.0 33.00% 17.1% Pro�ect: ut port Hote R= 1QQ P(R)= 3,Q(1 a cs y: CJB Jo No:C14-0507-01 Location: Renton WA Date: 3/3/2015 Southport f Iotel Renton,WA Conveyance Analysis- 100 Year 3r'3r201_>" 100-Year Backwater Backwater Analvsis Table hlannings Coefficient o.nza Southport Hotel S[orm Event Return Period 100 Proposed Site Conditions to Vault LocaHon Q L Pipe TPP Outlet Inlet Barrel Barrel Velocity Exce] Critical T�V Friction HGL Entry Entry Exit OuHet Headwater Inlet Approach Bend Bend Junc Loss Juncfion Headwater Rim Elev. O.K.? Downstream Upstream (cfs) (FT) Diam(in). n Elev Elev Area Velociri Head Check Depth Elev Loss Elev Ccef Loss Loss Control Depth Control Head Cceflicient Loss Coefficient Loss Elevation Diftereoce OuUe[ CB�A1 Pum edl 3.79 12 1� 0.024 12.00 18.00 I??7 3.090 0.148 1.00 0.79 13A2 0.140 I9.25 OSO 0.07 0.15 19.4' 0.97 19.22 -0.1� 0 000 0.00 0.00 1932 21.00 1.68 es CB#A1 Pum ed) CB�A2 3.79 4 1� 0.024 12.50 ]?.75 1.'_27 3.090 0.148 1.00 0.79 13.52 0.047 14.00 0.50 0.07 0.1� 14._2 0.7� 13.69 -0.1� 0 000 0.00 0.00 14.07 21.50 7.43 es CB#A2 CB#A3 0.76 S 8 OA24 18.00 18.80 0349 2.171 0.073 1.00 0.41 14.07 0.106 19.47 0.50 0.04 0.07 ]9.iR 0.75 1930 -0.0? 0 0 00 0.00 0.00 19.50 21.43 L93 ves CB#A3 CB#A4 0.40 60 S 0.024 18.80 19.40 0.349 1.155 0.021 1.00 D30 19.50 0.225 20.07 0.50 0.01 0.02 20,10 0.48 19.72 -0.02 0 0 UO 0.10 0.12 20.19 21.00 0.81 ves CB#AZ CB�B1 3.03 21 l� 0.024 15.85 1610 1.'_'? 2.473 0.095 lAl 0.70 16.83 0.156 17.35 0.50 0.05 0.09 I�A9 0.63 16.89 -0.09 L33 013 0.10 0.25 17J? 21.43 3.66 ves CBuB1 CBttBZ 2.92 48 15 0.024 16.10 163� 1227 2.381 0.088 1.01 0.69 ]7.77 0332 18.10 0.50 0.04 0.09 IA23 0.6] 17.11 -0.09 0.1 0.01 0.00 0.00 18.16 21.54 338 ves CB#B2 CBu B3 2.81 85 1� 0.024 1635 16.75 1.='_7 2288 0.081 1.00 0.67 18.16 0.542 18.70 0.50 0.04 0.08 18.82 0.60 17.50 -0.08 0 D IXl 0.00 0.00 18.?4 21.50 2.76 �es CB#B3 CBr�B4 2.61 134 15 0.024 16.7� 17.46 1.?'_7 2.123 0.070 1.00 0.6� 18.74 0.736 ]9.4? 0.50 0.03 0.07 19.58 0.57 18.17 -0.07 0 0.00 0.00 0.00 19.91 21.�0 1.99 es CB#B4 CBrkB� 2.26 75 15 0.024 17.46 17.79 1.?'_7 1.840 0.053 1.00 0.60 19.51 0310 ]9.R= 0.50 0.03 0.05 19.90 OS2 18.44 -0.OS 0 O.liO 0.00 0.00 19.8� 2L50 1.65 es CB#B5 CBikB�a 0.94 72 12 0.024 1739 19.00 0.755 1.196 0.0'2 1.00 0.41 19.8� 0.169 20.01 0.50 0.01 0.02 ?QUS D.44 19.44 -0.02 0 OOU 0.00 0.00 20.03 2150 1.47 es CB�BS CB�B6 1.09 70 12 0.024 17J9 18.13 0.'85 1383 0.030 1.01 0.4�1 19.89 0.220 20.06 0.50 0.01 0.03 ?0.11 0.47 18.60 -0.03 0 0.00 0.00 0.00 20.08 21.50 1.42 es CB#B6 CB�B7 0.88 ]13 12 0.024 18.13 1828 0.'85 1.117 0.019 L01 039 20.08 0.231 20.31 OSO 0.01 0.02 ?034 0.42 18.70 -0.02 036 0.01 0.00 0.00 2033 21.83 1.50 es CB�B7 CBn B8 0.58 14� 12 0.024 18.28 18]2 0.'3> 0.?38 0.008 1.00 032 20.33 O.129 20.46 0.50 0.00 0.01 =0,4' 033 19.0� -0.01 036 0.00 0.00 0.00 20.46 21.83 1.37 •es CB#BS CBR B9 033 l OR 12 0.024 18.72 19.60 0.78� 0.422 0.003 1.26 02^ ?0.�6 0.031 20.60 0.?0 0.00 0.00 =i�i�'; 028 19.88 0.00 0 U 00 0.00 0.00 ?0.60 21.10 Q50 ves Southport Hotel Backwater Analysis- 100-Year Renton, WA 3!3/201� % COUGHLINPORTERLUNDEEN / �;. --- - -----_ ---------------------- - - ------ � � KCRTS STORMFILTER PEAK FLOW CALCULATIONS � /; EAST STORMFILTER TIME SERIES: �� KCRTS Program. . .File Directory: j C:\KC SWDM\KC DATA\ [C] CREATE a new Time Series j / S T ;,;;: 0.00 0.00 O . 000000 Till Forest 0 . 00 0.00 0. 000000 Till Pasture 0 .01 0. 00 0.000000 Till Grass '' 0 .00 0.00 0.000000 Outwash Forest j� 0.00 0.00 0.000000 �utwash Pasture j 0.00 0.00 0.000000 Outwash Grass j" 0.00 0.00 0.000000 Wetland � 0.37 0.00 0.000000 �mpervious EAST_SF.tsf T 1.00000 � , F j WEST STORMFILTER TIME SERIES: � , [C] CREATE a new Time Series j' ST j,� 0.00 0.00 0.000000 Till Forest / 0.00 0.00 0 . 000000 Till Pasture '� " 0.17 0.00 0. 000000 Till Grass 0.00 0.00 0.000000 Outwash Forest 0.00 0.00 0.000000 Outwash Pasture 0.00 0.00 0.000000 Outwash Grass 0.00 0.00 0.000000 Wetland 1 .55 0.00 0.000000 Impervious WEST SF.tsf T 1.00000 /// F %//� % �-, �' j j' �' j j / j. � � 8�1 SECOND AVENUE, SUITf 900 SEATTLE, �"JA 98104 % P 206.343.0460 r cpiinc.com /� j� COUGHLINPORTERLUNDEEN EAST STORMFILTER FLOW FREQUENCY ANALYSIS Time Series File:east sf.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFSj Period 0.176 6 8/27/O1 18:00 0.442 1 100.00 0. 990 0.123 8 9/17/02 17:45 0.336 2 25.00 0.960 0.336 2 12/08/02 17: 15 0.239 3 10 .00 0.900 0.142 7 8/23/04 14: 30 0.198 4 5. 00 0.800 0.188 5 10/28/04 16:00 0. 188 5 3.00 0. 667 0.198 9 10/27/05 10:45 0.176 6 2.00 0.500 0.239 3 10/25/06 22:45 0 . �42 7 1 . 30 0.231 0.442 1 1/09/08 6:30 0. 123 8 1 . 10 0.091 Computed Peaks 0.405 50. 0� 0. 98� WEST STORMFILTER FLOW FREQUENCY ANALYSIS Time Series File:west sf.tsf ?roject Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.738 6 8/27/Ol 18:00 1 .91 1 100.00 0 . 990 �.516 8 9/17/02 17:45 1.43 2 25.00 0.960 1 .43 2 12/08/02 17:15 1.01 3 10. 00 0. 900 0.595 7 8/23/04 14:30 0.836 4 5.00 0 .800 0.792 5 10/28/04 16:00 0.792 5 3.00 0. 667 0.836 4 10/27/05 10:45 0.738 6 2.00 0.500 1 .01 3 10/25/06 22:45 �. 595 7 1 . 3C 0 .231 1 . 91 1 1/09/08 6:30 0.516 8 1.10 0.091 Computed Peaks 1 .75 50. 00 0. 980 2 % COUGHLINPORTERLUNDEEN / East StormFilter Calculations 2-year storm flow (per KCRTS report, attached): 0.176 CFS = 79.0 gpm 35% of 2-year storm flow (per KC SWMM 6.5.5.1.2): 27.65 gpm Cartridges Required (per KC SWMM Table 6.5.5.A, below): (4) 18" Cartridges = 30 gpm design flow > 27.65 gpm TABLE 6.S.S.A MAXIMUM STORMFILTER DESIGN FLOW RATES PER CARTRIDGE FOR BASIC TREATMENT WITH ZPG MEDIA � Effective Cartridge Height(inches) 12 l 8 27 � j.' j ; Cartridge Flow Rate(gpm/cartridge) 5 7.5 11.3 j,, / . / ; / j/ / j�;%; � %� , j� / /; / ;,; / /� � �� ,� �,�-„ � ji;, /j ,j COUGHLINPORTERLUNDEEN ''� � ;j 'j West StormFilter Calculations j � ;/ 2-year storm flow (per KCRTS report, attached): ;i/ 0.738 CFS = 331.23 gpm %/ / 35% of 2- ear storm flow er KC SWMM 6.5.5.1.2 : / Y tP ) , 115.93 gpm ,/ ,,/ %j Cartndges Required (per KC SWMM Table 6.5.5.A, below): / (11) 27" Cartridges = 124.3 gpm design flow > 115.93 gpm �j j ./ �� j / ':,'� � /. / / / �% / /// � TABLE 6.S.S.A MAXIMtiM STORl�-iFILTER DESIGN FLOW 2ATES PER CARTRIDGE FOR BASIC TREATMENT WITH ZPG MEDIA Effective Cartridge Height(inches) 12 l8 27 Cartridge Flow Rate(gpm/cartridge) 5 7.5 11.3 / II ,, / I :j '�� i' �� I i�ii , / / �� j II /j �/ COUGHLINPORTERLUNDEEN / �j ,� - - ---__--- --- - / South ort Wetvault Sizin Calculations �� P J ,/ ��'� �� Following the procedure outlined in 6.4.1.1 of the King County Stormwater Design Manual: ,/ ; j � Step 1: Identify required wetpool volume factor �,;:�� = 3 since bas�c %/ f � ) ,;;/ 'j Step 2: Determine rainfall (R)for the mean annuat storm ;j Using Figure 6.4.1.A, � � R = 0.47" = 0.039' � Step 3: Calculate runoff from the mean annual storm : j V,- = R�0.9Ai +0.25At9 + 0.10A�p +O.OlAo� / ' �/ A� = 190,000 SF � Aty = 0.00 SF ; ��j Ar f = 0.00 SF � � � Ao = O.00 SF ;;:j V, _ (0.039 FT)(0.9)(190,000 SF) � %;�j � V,. = 6,669 CF � ,� �� Step 4: Calculate required wetpool volume � Vb =f Vr '�� . ';i: V6 = (3)(6,669 CF) Vb = 20,007 CF With inside dimensions of 178.5'x 25', and a live storage depth of 4.8',the provided volume of the existing I vault is approximately 21,420 CF, so, I 21,420 CF > 20,007 CF I Vproroided � Vrequired II Therefore,the existing vault is adequate for reuse as a wetvault to provide basic water quality � treatment. i Additionally, the existing wetvault must meet the requirements of City of Renton Amendment to KCSWDM Section 6.4.2. PROJECT Southport Hotel DESIGNED BY BGG DATE 04/01/2015 JECT NUMBER C140507-01 CLIENT MG2 CHECKED BY BSB SHEET OF � COUGHLIN PORTER LUNDEEN A CONSULTING STRUGTURALAND C�VIL ENGINEERING CORPORATION � �/NAL ��/40 GIV� �� Q , ��T N"`-+SMV � A�'�=A (�o.�/T2/l�vs��i ro ►✓.�r� l�d��rJ' d/f�G1- ��lC�l�✓p¢5 AGC. i�If'�ND�'$ ' 'qLoos95 yc./i7sf I�i�i f1 TRAfi/G Lo�90�^�j I�J�C�"/7o.y ,.r',E.NE,C/El7�tX'1 �121�'1GbS T?� fl�6Q,3 OF "C a..+r:�2 "� 7e9��c �/DIUrr1E !1� STD2/r1 /r�9�IrYirlrfrNt [ �6►�F Cfl�a�sr ��r�ef. i TA•7,� C h.�,,a��s i9�R ra � �iw�� ¢.�3 AceFs �ic.-S �uP C � �/ : 71, oe � I ��., lV�� ( " �l,� �u� ' ?'° ��=5 y�Y • �� bn�.e.�,-.r� � r�trM�,,r s�i2,w� 6�� o�' a,� �a�6$(?,0'� �/.z$�, � � {�c(Q Vol,� �a��a � l�,C� � �-,-�,.� 1��oe1c S ��.,(��aa . ( ti(.�(� Vo1u►�.� r��D�n, ��M � Yrw ea- $,'I Z. � ��ls r�v�',o.� ,l�.� � 4 9.� ( 'esr �w ��x 3► X 9.�� ,5� - v�s�rk�ar-�e., = 8�4`�.oo c.F � 31x31 � �,r, _ 9,I�r.So c� 7� s�t,.�7�ar^�.' (7�778,5�cF I { g 5�`;Faua� i 7,7-78.5 ` �,p 7 �a7a i � /�,�� a I OP .'f= V PuLT �t�l St�L• prl I ,o O .� � �vr'J �2ErE. �OA-��• , � 8 U v � � � EXISTING WETVAULT CALCULATIONS ° FROM 2001 SOUTHPORT MASTER PLAN Projec� �v7t-��ef Designed By: �v�}� Date a.��1/0l Project No: Client Checked By. Sheet of 217 PINE STREET• SUITE 300•SEATTLE.WA 98101 •P.206/343-0460•F.206/343-5691 2/14/O1 3 : 37 :34 pm Coughlin, Porter, Lundeen Inc. page 1 SOUTHPORT C990570-01 WATER QUALITY DESIGN StormFilterFlows BASIN SUMMARY BASIN ID: WQVault NAME: 64% 2yr Precip - WQ Storm SBUH METHODOLOGY � TOTAL AREA. . . . . . . : 4 .33 Acres BASEFLOWS: 0 . 00 cfs ( RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 1.28 inches AREA. . : 0 . 00 Acres 4 .33 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 � TC. . . . . 6 .30 min 6 . 30 min ABSTRACTION COEFF: 0 .20 r PEAK RATE: I . 06 cfs VOL: 0 .38 Ac-ft TIME: 480 min I � 16��5� � � � � ! � � � � � ' � EXISTING WETVAULT CALCULATION`. � FROM 2001 SOUTHPORT MASTER PLAN � � . - - ,� Z ��:� , __ ,�� , ;. . � ' �� I � � l` � S% r �I =S '\ t~ ,- d . � 7"�. �. �� .�+`. .. \ "�' . • � Z` ; ,. � .. �� , � � �jFy. i . 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I "' - � � � � �� . . . ��. � .. : . _ 1.. __:-_. �,�_..� � _- -._-_.- -�- , -- I 1 i i C�=° I \ % , ,.,. ,. .. ,, .... �w i -{ ' � � � � l � 1 T � _ i �. , , - � � . i %, _ . . . .; � � ` � �__) — ., �� ` � _ t , � - - - __ . � � __ \ ,t` �� \ � � ' / � l.i= / . _..... �. . . = ' ,. � � � COUGHLINPORTERLUNDEEN P R O P O S E D P G � s M A P � 1" = 80' , ' 801 SECOND AVENUE,SUITE 900 / SEATTLE,WA 98104 SOUTHPORT HOTEL , P 206.343.0460 / F 206.343.5691 / cplinc.com - I COUGHLINPORTERLUNDEEN Appendix B GEOTECHNICAL REPORT Geotechnical Engineering Design Study, Southport Hotel Prepared for Seco Development by HartCrowser, Inc Dated April 18, 2014 27 �- _._ _ _ _ _ , .._ . >-. . � . 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Contents I'I PURPOSE AND SCOPE OF THIS STUDY 1 SITE AND PROJECT DESCRIPTION 1 Groundwater 2 GEOTECHNICAL ENGINEERING CONCLUSIONS AND RECOMMENDATIONS 2 General Considerations 2 Geotechnical Recommendations Supporting Structural Design 3 Seismic Design Issues 3 Ground Improvement and Spread Footing Foundations 3 Spread Footing Design and Settlement 5 Pile Foundation Design 5 Lateral Pile Capacity 6 Pile Installation 8 Floor Slab Design 9 Below-Grade Elements and Structural Fill 10 Fill and Settlement 10 Underslab Drainage for Buildings 11 Pavement Support 11 Excavation Groundwater Control 11 RECOMMENDED ADDITIONAL GEOTECHNICAL SERVICES 12 Ground Improvement Verification 12 LIMITATION 12 TABLES 1 Pile Group Reduction Factors for Coefficient of Variation of Horizontal Subgrade Reaction 8 � ii 19014-02 H/�'jCfjOH/S[/; April 18,2014 ii I Contents FIGURES 1 Vicinity Map 2 Site and Exploration Map 3 Generalized Subsurface Cross Section A-A' 4 Generalized Subsurface Cross Section B-B' 5 Laterally Loaded Piles in Elastic Subgrade Deflection and Moment Criteria 6 Laterally Loaded Piles in Elastic Subgrade Deflection and Moment Criteria APPENDIX A Field Explorations Methods and Analysis APPENDIX B Laboratory Testing Program � APPENDIX C ! Explaration Logs Completed by Geotech Consultants, Inc. 1999 �s 19014-02 1i April 18,2014 �T�� — Geotechnical Engineering Design Study Southport Hotel Renton, Washington PURPOSE AND SCOPE OF THIS STUDY The purposes of this study were to: ■ Collect data and reports and assess subsurFace conditions for the planned hotel; ■ Assist the structural engineer with establishing foundation design criteria;and ■ Provide geotechnical engineering recommendations related to design and construction. The scope of this study included: ■ Reviewing field explorations and a report for the site completed by Hart Crowser, dated December 15,2000; ■ Reviewing earlier work for the site completed by Geotech Consultants, Inc. (Geotech), dated April 9, 1999; ■ Identifying and analyzing the geotechnical engineering considerations;and ■ Preparing this report. Applicable logs of Hart Crowser and Geotech explorations are included in this rep�rt. SITE AND PROJECT DESCRIPTION The site is located on the s�uthern edge of Lake Washington, in Renton,Washington,as shown on Figure 1. The project consists of a hotel and conference center constructed at grade. The development area immediately fronts Lake Washington, and is located between The Bristol residential units and the Boeing property. A Site and Exploration Plan sh�wing the approximate location of the soil borings and cone penetration tests is presented on Figure 2. Reprinted logs of Hart Crowser's soil borings, and corresponding geotechnical laboratory testing,are included in Appendices A and B, respectively. Figures 3 and 4 show applicable cross sections,A-A'and B-B' (as depicted on the site and exploration plan)for the site, which are based on the site explorations. It should be noted that the depth to, and thickness of,the soil layers vary greatly throughout the site,as discussed later in this report. Within the proposed development site,starting at the ground surface and moving downward,we typically encountered the following soils: ■ Very loose to medium dense,non-silty to silty Sand. This layer extends from the existing grade to a depth of about 20 to 50 feet below the existing ground surface. Interbedded with only a few � � 19014-02 ��ws'�[.fj April 18,2014 2 I Southport Hotel thin layers of soft silt,this sand layer is considered to have the potential to liquefy during a seismic event. This layer will not provide adequate foundation support in its current condition. ■ Soft to medium stiff and stiff Silt. This layer varies from 0 to about 35 feet thick,and is also unsuitable for foundation support. ■ Medium dense to dense,slightly silty Sand. With a thickness of about 10 to 45 feet,this layer is considered a bearing unit for deep foundations. ■ Very soft to medium stiff and stiff Silt and Clay. With a thickness ranging from 0 to about 45 feet, this layer is likely to cause elastic and/or consolidation (time-dependent)settlement of the deep foundations. ■ Dense to very dense,slightly silty Sand. This layer is not encountered until about 130 to 140 feet below existing grade,except in the southern part of the site,where the layer appears at a I shallower depth,approximately 70 to 100 feet below existing grade. � Groundwater Groundwater was encountered in the explorations at depths ranging from 3 to 9 feet below existing grade. Note that the groundwater levels were identified at the time of the explorations,and that the groundwater elevation will be tied primarily to the level of Lake Washington,which varies by only about 3 feet annually. The groundwater gradient is from south or southeast t�north or northeast,as groundwater flows from the upland areas toward the lake. GEOTECHNICAL ENGINEERING CONCLUSIONS AND RECOMMENDATIONS The following section includes design criteria addressing site preparation,structural design issues,civil design issues,and seismic design. These design criteria are based on the preceding site description, applied loads as provided by the design team,and the subsurface conditions revealed by the explorations completed at the site. Note that subsurface soil conditions are based on explorations accomplished at discrete locations at the site. Soil properties inferred from the field and laboratory tests formed the basis for developing our geotechnical recommendations contained in this report. The nature and extent of variations between the explorations may not become evident until construction begins. If variations then appear, it may be necessary to re-e�aluate the recommendations in this report. As the design criteria continue to evolve,we need to continue to consult with the team so that our recommendations remain current. General Considerations The soil conditions and the structural load requirements have led us to consider two potential foundation support alternatives. The first is driven piles—either precast concrete or driven grout. These piles can be installed in a conventi�nal fashion around the site,with the pile lengths governed primarily by the thickness of the supporting layer. The pile support alternative does not address the site liquefaction potential. The piles and floor slab will be designed so that even if a major earthquake s�r 19014-02 � April 18,2014 �T�wwr Southport Hotel I 3 causes widespread liquefaction and ground surface settlement,the building foundations,floor slabs, il and underslab utilities would continue to function. � The second alternative is to complete ground improvement using stone columns or Geopiers across I the entire site and constructing spread footings to support the building loads. The ground improvement will mitigate the shallow liquefaction potential for the site,allowing spread foundations to be used with slabs-on-grade,and grade support for the utilities. With each alternative,the timber piles supporting the existing steam plant will remain and will be relied upon for support of the new building. Geotechnical Recommendations Supporting Structural Design Seismic Design lssues Based �n our review of the borings drilled and cones pushed at the site,we have concluded that the average Standard Penetration Test blow counts and nature of site soils in the upper 100 feet represent an IBC Site Class F,which would be improved to Site Class E with ground improvement. During a significant seismic event,there is a risk of liquefaction of the site soils through the upper 20 to 50 feet, as disclosed by materials encountered in the borings. Widespread liquefaction could result in ground surface settlement both below the buildings and in the access areas around the buildings. Unless ground improvement techniques are used,we recommend that underslab utilities be hung from the slab and/or grade beams rather than grade-supported. Exterior pavement,walkways, utilities, and grade-supported structures are subject to distress from liquefaction and may not function after a major seismic event. Foundation piles for the buildings(if used)should be largely unaffected, except that they may not be designed for lateral resistance or frictional support in the liquefaction zone. Deep foundations designed in liquefied soil shall be classified as columns per IBC section 1810.1.3. Ground improvement alternatives to reduce the areas of potential liquefaction are probably limited to stone columns or Geopiers. Other methods such as deep dynamic compaction are apparently not applicable at the site, because the groundwater table is too high to be effective. Even if no ground improvement steps are taken,the installation of driven piles at each of the column locations will result in some increased soil densification,and will reduce the likely extent of liquefaction. Ground/mprovement and Spread Footing Foundations As an alternative to driven piles,ground improvement such as vibro-replacement stone columns or Geopiers combined with spread footings can be used to support the buildings. Ground improvement beneath the building not only densifies the soil to allow use of shallow foundations, but also mitigates the seismic risks associated with liquefaction (see subsequent discussion). � 1.I 19014-02 �r��ws(.J; April 18,2014 4 I Southport Hotel Ground improvement design for this site is governed by the liquefaction mitigation, control of post- construction settlement,and by the foundation support requirements. Ground improvement effectively prevents soil liquefaction in the improved zone by increasing the density of the soil, providing for stress redistribution during a seismic event,and by providing enhanced drainage paths for pore water dissipation. If liquefadion occurs below the improved zone,the ground improvement provides a buffer between the affected soil and the foundations. Liquefaction Design. Hart Crowser has estimated that the site is susceptible to liquefaction during a Maximum Considered Earthquake(MCE) (2012 IBC). That event has a 2 percent probability of exceedance in 50 years. Without ground improvement,the estimated liquefaction settlement is as much as 2 to 3 feet. The degree of densification is a function of the soil type, silt and clay content, plasticity of the soils, pre-densification relative density, installation methods,and specific design and spacing between columns. Soils with less than 15 percent passing the No. 200 sie�e with a clay content of less than 2 percent will usually densify upon vibration. Soils with higher fines and/or clay content will be improved less by ground improvement, and a tighter spacing will be required for effective mitigation. The stress redistribution effect assumes that the relatively high stiffness of ground improvement will absorb more shear stresses than the weaker surrounding soils during ground shaking,thereby, reducing the shear stresses applied to the soil. In addition,the improved columns provide a path for excess pore water pressures,which result in soil liquefaction,to dissipate during the earthquake. Another potential negative effect of liquefaction is lateral spreading,or movement of the soil near the shoreline. Properly designed ground improvement will mitigate the risks of lateral spreading by stabilizing the block of soil supporting the building. Performance Criteria. Ground improvement shall meet the following minimum requirements: ■ Improved ground shall be capable of providing an allowable bearing capacity for individual and combined footings of 6 kips per square foot(ksf). ■ Post-construction static settlement of footings should be less than 1 inch. ■ Post-construction differential settlement of footings should be less than 1/2 inch over a horizontal distance of 50 feet. ■ Improved ground shall be capable of providing an allowable bearing capacity for tower crane footings of 6 ksf with less than 1/2 inch of post-construction differential settlement across the crane foundation. ■ Improved ground should limit post-earthquake differential foundation settlement to 1-1/2 inches over a horizontal distance of 50 feet. ■ Improved ground shall extend at least 20 feet beyond the building footprint on the lake side of the building and provide adequate soil resistance to the foundations in a post-earthquake condition. � 19014-02 � April 18,2014 �{/�T��ws� Southport Hotel I 5 ■ Ground improvement shall extend to a minimum depth of 45 feet below the planned footing base elevation within 100 feet of the seawall/revetment on the Lake Washington shoreline, and to a minimum depth of 35 feet below the planned footing base elevation beyond 100 feet from the shoreline. Assume the bottom of the footings is at an average depth of 5 feet below the existing grade. Final depths of ground improvement shall be established by the Specialty Contractor. Verification Testing. The effectiveness of ground improvement should be verified during construction by establishing performance criteria and quality control procedures. These criteria and procedures ensure that the design criteria are achieved following installation. Standard Penetration Tests(SPT) and cone penetrometer tests(CPT)are often performed in soil zones between stone columns to verify the densification effect. Based on our design assumpti�ns, minimum SPT blow counts of 30 should be achieved in footing areas with slightly lower values acceptable in slab areas. CPT tip resistances of 150 tsf are required below footings,and 100 tsf below slabs. Due to the requirements for high load- bearing capacity,we recommend conducting a load test in each test section in the selected footing areas to verify design bearing capacity. Spread Footing Design and Settlement After the ground improvement has been completed,the footings are constructed in the usual fashion The contractor should ensure that loosened material is cleaned from the excavations, and the surfa� is firm and non-yielding. We expect approximately half of the settlement could be time-dependent, resulting from consolidation of the lower silt/clay layer. If the buildinE is constructed in phases. th� could be abrupt differential settlement between the pha� Pile Foundation Desigr: If piles are to be used,we recommend using only driven piles at the site for two reasons: it is easier identify the sometimes irregular bearing layer if the piles are driven rather than drilled;and the drivi r;�; process will increase the soil density and reduce the potential for liquefaction. Appropriate types of driven piles, based on the load-carrying requirements, are the DeWitt dri�en grout pile and precast concrete. Pile lengths will vary from 60 to 75 feet across the site. For planning, we recommend assuming an average length of 70 feet. Because the supporting sand layer is�f limited thickness,we will put limits on the driving and penetration lengths to avoid punching through the layer. In all likelihood,these piles will not be driven to refusal. The following allowable pile capacities apply across the site: ■ 16-inch DeWitt driven grout 100 tons ■ 16-1/2-inch precast concrete 110 tons These capacities take into account strength loss in liquefiable soils during a major earthquake and the downdrag loads that could result after the event. They include a factor of safety of about 2.0, and assume a load test will be used to confirm the capacity. � Y 19014-02 �� April 18,2014 6 I Southport Hotel The following uplift capacities apply across the site,assuming no friction contribution in the upper potentially liquefiable zone: ■ 16-inch DeWitt driven grout 25 tons ■ 16-1/2-inch precast concrete 30 tons Soils below the bearing layer are loose in many areas. In addition, at depths of about 100 to 120 feet is a compressible soil zone in some locations,as disclosed by several of the explorations. We estimate that the piles could experience an initial compression of as much as 1 inch as the building loads are applied. Over a period of several months following construction,an additional 1-1/2 to 2 inches of deep-seated soil consolidation and building settlement could occur. We do not expect this consolidation to result in abrupt differential settlement, but portions of the structure built at different times could experience differential settlement. The capacity and settlement estimates are based on assumed column loads of as high as 1500 kips. Latera!Pile Capacity Lateral resistance and deflections of vertical pile foundations are governed primarily by the lateral capacity of near-surface soils and the strength of the pile itself. The design lateral capacity of the vertical piles will depend,to a large extent,on the allowable lateral deflections of the piles. Use of the procedure discussed below, incorporating the design charts on Figures 5 and 6,will allow the structural engineer to estimate the pile deflection and moments within the pile at any point at or below the pile cap for a given loading. Note, however,that if no ground improvement is completed, under severe seismic loading the piles will experience no lateral resistance in the zone of liquefaction, which could extend to depths of 50 feet. In addition to the design charts provided on Figures 5 and 6, we can also provide input soil parameters for a computerized laterally-loaded pile analysis(LPILE). These input parameters include soil unit weight, shear strength,and lateral subgrade reaction m�dulus(k). Once the pile type and pile sizes are determined later in the detailed design stage,we can either perform the LPILE analysis to provide deflection,shear force, and bending moment of the pile;or we can provide input soil parameters to the structural engineer for their LPILE analysis. Development of lateral pile criteria requires an assumption of the degree of fixity at the pile head by the structural engineer. A pile is considered free-headed if the top is free to rotate. If the top �f the pile is fixed against rotation by embedment in a pile cap that is sufficient to develop a fixed-end moment,the pile is considered restrained and fixed-headed. We recommend that the structural engineer evaluate the degree of fixity and then linearly interpolate between results outlined from Figure 5 (true fixity at head)and from Figure 6(true free-headed condition). In addition to the pile head fixity condition,the following information is required to determine lateral pile deflections and moments: � 19014-02 Y April 18,2014 �{/�/��ws� Southport Hotel I 7 Moment and Deflection Equations: Free-Headed Condition Fixed-Headed Condition Y_ A,:PxzTj+By�M.�TZ Y _ Ay. Px_x T3 EI EI EI M = An, PxT T + 8,,, M.� M = A„, P_CX T Where: Y = Deflection at any point at or below the ground surface, I M = Moment at any point at or below the ground surface, P,� = Shear applied to the pile at the ground surface (x-x plane), '' Mxx = Moment applied to the pile at the ground surface (x-x plane), A,,, Bti. = Deflection coefficients from Figure 5 or 6, ' Am, Bm = Moment coefficients from Figure 5 or 6, EI = Flexural stiffness of the pile, EI T = Relative stiffness factor= � — nh nn = Constant of horizontal subgrade reaction, 2T = Assumed depth to point of zero deflection. The rate of increase of horizontal subgrade reaction, nn, is related to the stiffness and density of the soil. The soil above about 2T(two times the relative stiffness factor) usually controls the lateral capacity of the pile. For site soils encountered in this zone,an appropriate general value of nn is estimated to be 10 pounds per cubic inch (pci) under static loading conditions. The coefficient of variation of horizontal subgrade reaction should also be modified for pile group effects. Table 1 outlines the recommended reduction factors depending on pile spacing. � Ii 19014-02 �{�j']'��ws[.� April 18,2014 8 I Southport Hotel Table 1 - Pile Group Reduction Factors for Coefficient of Variation of Horizontal Subgrade Reaction Pile Spacing in Direction of Loading Subgrade Reaction Reduction Factor D= Pile Diameter R 8D 1.00 6D 0.70 4D 0.40 3D 0.25 For the pile to develop fixity, a total embedment of at least 4T(four times the relative stiffness factor) ' must be attained. With 4T or greater embedment,the ultimate resistance to an applied lateral load is governed primarily by the strength characteristics of the pile and not the strength of the soil. In contrast,should the pile be embedded to a depth of only 2T or less,the ultimate resistance to lateral loads would be governed primarily by the strength of the soil with the pile acting as a rigid member(or pole). An embedment of between 2T and 4T would be considered an intermediate case, i.e.,the ultimate lateral loading depends on both the soil and the pile strength. For the typical case at this site,we anticipate that an embedment greater than 4T will be realized, given the embedment requirements for vertical capacity. The moment formulations calculated using the procedures do not contain a factor of safety. The structural engineer should incorporate a suitable factor of safety in the lateral load design or adopt an allowable deflection criteria, and should verify the strength of the pile t� resist the applied lateral loads. The pile cap, upon deflection, will contribute some lateral resistance to the foundation system. The equivalent fluid weight for passive resistance of compacted fill above the water table is 300 pcf. This is an ultimate value that assumes that the pile cap can move laterally at least 1 percent of its height (height defined as depth from adjacent grade to the bottom of the pile cap). For less lateral movement,the ultimate passive resistance should be reduced linearly to zero for no lateral movement. The lateral resistance against the pile cap assumes the confining soil is compacted structural fill. Pile lnstallation We recommend the following: ■ Space piles within groups no less than three times the pile diameter on center. ■ Verify pile capacity in the field based on a wave equation or a dynamic pile driving formula used in conjunction with the final few driven feet. Such a formula should take into consideration various physical factors such as energy of the hammer,the size and length of the piles,and modulus of elasticity of the pile materials. In our opinion,an appropriate formula would be the Danish (So) pile driving formula. � 19014-02 1i April 18,2014 ��R Southport Hotel I 9 The So pile driving formula is presented below: aE,. Q S+ So Where: aEr L 1. z S° � 2AE J And Q= Ultimate pile capacity in pounds E� = Rated hammer energy in foot-pounds a = Hammer efficiency=delivered energy=rated energy=(about 0.8 unless measured) L= Length of pile in feet A= Cross sectional area of pile in square inches E= Modulus of elasticity of pile material in pounds per square inch S= Final set(penetration per blow)in feet. ■ To correspond to the allowable design value,apply a factor of safety of 2.5 to the ultimate pile capaciry as determined by the wave equation or the above pile-dri�ing formula. I ■ We expect that a certain percentage of the piles will need to be redriven on the day after the initial driving. Redriving is a better way to apply the wave equation or pile driving formula to '' estimate the capacity,since the ground has a chance to "set up"following initial driving, and ' regain the long-term strength. For planning, assume that 10 percent of the piles will be redriven. Hart Crowser should review the pile plans and specifications,and estimate the design pile lengths prior to construction (and ordering piles, if precast concrete are used). As noted earlier,a length of 70 feet is appropriate for planning,and the lengths in the field will be carefully monitored to protect against overdriving,and punching through the bearing layer. To assess stresses within the pile the contractor should provide a driveability analysis for the driving setup they plan to use. Hart Crowser should review the analysis. Floor Slab Design For the pile foundation support alternative,we recommend designing the floor slab as a structural slab,supported by the pile caps and grade beams. For the stone column/spread footing alternative, a � /.1 19014-02 ��w�R April 18,2014 10 I Southport Hotel grade-supported slab can be used. As subsequently recommended,a 6-inch layer of clean sand and gravel should underlie either slab alternative. A vapor barrier is not required. BeJow-Grade Elements and Structural Fil! Footings, pile caps,or other below-grade elements backfilled on one side only can be designed using soil pressures estimated using equivalent fluid weights for the soil. For active conditions,where the wall is free to deflect slightly,the appropriate fluid weight is 35 pcf. For passive resistance,the appropriate fluid weight is 300 pcf. For at-rest conditions,where no deflection is allowed,the appropriate fluid weight is 55 pcf. Structural fill will be required in some areas around the site. Generally,the structural fill should consist of clean, well-graded sand or sand and gravel to allow placement and compaction under wet , conditions. Compaction to 95 percent of the modified Proctor maximum dry density is required in �' bearing areas or slabs-on-grade. Lower compaction levels are acceptable in non-bearing areas. For example, in paved areas,a level of 92 percent is acceptable. In landscaped areas,88 to 90 percent is acceptable. Beneath structural slabs,the fill needs only be compact enough to support the curing slab. Crushed concrete can be used as fill below structural slabs,and at depths greater than 2 feet below the slab in slab-on-grade areas. Crushed concrete should have a maximum size of 4 inches. Fil!and Settlement Placement of more than a few feet of fill outside improved ground will include consolidation settlement of several inches. Roadway fill areas could be preloaded or surcharged to induce the settlement before paving. Another alternative could be the use of a lightweight embankment fill called Geofoam. This is a material supplied in blocks or sheets that is strong enough to support some fill and pavement loads. Utilities will settle with the surface of the fill, since the settlement is deep-seated. If the fill is placed first and the utilities after, some of the utility settlement will be eliminated. Utility connections should be as flexible as possible,and utility grades and slopes should be adjusted, as appropriate,to adapt to the expected settlement. Improved areas will settle less than non-improved areas. Below the water table(estimated to be as high as elevation 17 and 19 feet,or about 3 feet below the current site grade), our ability to dewater sufficiently to allow for a stable trench and workable conditions is uncertain. Old photographs of construction at the steam plant,and our experience nearby,suggest that the groundwater can be controlled using well points, sumps,or wells. If this is the case,then a traditional trench box to support the excavation combined with area dewatering could be cost-effective and efficient. If the water cannot be controlled, more costly alternatives such as ground freezing may need to be considered. In either case,the pipe bedding and backfill should consist of high quality sand and gravel with a low fines content,since the work will be completed in wet conditions. A well-graded sand and gravel can even be placed with some water in the excavation. If the bottom of the excavation is in peat or soft � 19014-02 � April 18,2014 �T�Ows� Southport Hotel � 11 silt,which is possible, based on the explorations, a separation fabric should be used to line the pipe trench and keep the clean bedding and backfill from becoming contaminated with fine-grained soil. Underslab Drainage for Buildings We recommend that no underslab drain network be installed for either a pile foundation or a spread footing foundation system. The slab should be underlain by at least 6 inches of well-graded sand or sand and gravel with a fines content of no more than 3 percent by weight, based on the minus 3/4-inch fraction. Perimeter drains and drains at the base of below-grade walls may still be needed, although we can review requirements on a case-by-case basis across the site. Pavement Support Haul roads, depending on their location around the site,could travel over relatively firm ground or across pockets of soft soil. We have flexible requirements for the haul road base. It can consist of quarry spalls, or crushed rock,or crushed rock with an ATB surface. This is a decision that the contractor should have some control over,since the nature of the ground,the traffic loading,the weather conditions,and other non-design factors will affect the subgrade needs. For the permanent roadways, (not considered to be arterials)we recommend that the upper two feet of fill or natural ground be well-compacted (to at least 92 percent of the modified Proctor maximum dry density)and firm and non-yielding. The pavement subgrade could consist�f 4 inches of asphalt over 6 inches of crushed rock,with heavier sections in the major truck access areas,and lighter sections in low-traffic areas. We expect that the roadways will undergo some widespread settlement over time in the high fill areas, but abrupt differences in settlement are not expected. Excavation Groundwater Control Our exploration program consisted of limited test pit excavations to observe the shallow excavation conditions. We noted that while groundwater is present in the excavations, it should flow slowly enough to be controllable using conventional means. Team experience at nearby sites and historical photographs of work at the steam plant support this position. In some locations this will not be the case, but in general,shallow excavation for construction of pile caps or footings do not require a detailed dewatering plan if the depth of the cut is less than about 7 feet below existing grade. Reasonably dry conditions should be able to be maintained by pumping from one or two sumps located within each excavation. The excavation side walls should be protected from sloughing by using steel sheets or similar protection. An alternative method would be to install a number of separate sumps just outside the excavation footprints to lower the water table o�er a wider area than just one pile cap. A 12-inch slotted plastic casing or culvert pipe placed about 2 feet below the bottom of excavation and backfilled on the outside with pea gravel would serve as the sump. Deeper excavation (such as may be required for elevator shafts)will most likely require an active dewatering system using drilled wells or well points. We would expect to pump significant quantities � � 19014-02 �{/,�j'�QN/,s[./= April 18,2014 12 I Southport Hotel of groundwater below depths of about 10 feet,and excavations of this depth should be conducted with great care to avoid sudden collapses of side walls and loss of soil integrity in the base. RECOMMENDED ADDITIONAL GEOTECHNICAL SERVICES We see the potential for Hart Crowser to complete additional services in support of the design and construction of the proposed facility. Ground Improvement Verification Liquefaction mitigation of improved ground conditions should be verified by Hart Crowser using cone penetration tests(CPTs)at selected locations. A set of pre-and post-installation CPTs should be completed for every 15,000 square feet to a minimum depth of 50 feet below ground surface, located midpoint between adjacent piers. We should do a minimum of 5 CPTs before ground improvement and a minimum of 10 CPTs after ground improvement. Daily records during improvement should be kept and signed by the Specialty Contractor and verified by a representative of Hart Crowser. Daily records should include for each installation,at a minimum: ■ Reference number or installation location ■ Date and time of installation start and complete ■ Depth of penetration ■ Quantity of stone/rock/sand used ■ Densification and installation forces used ■ Obstructions or delays ■ Unusual conditions encountered Services during Construction. During the construction phase of the project,we recommend that Hart Crowser observe the following activities: ■ Placement of structural and drainage fill at the site; ■ Observation of the installation of pile foundations or stone columns; ■ Observation and verification of the suitability of all excavated surfaces; ■ Excavation and placement of foundations floor slabs; ■ Other geotechnical considerations that may arise during the course of construction. The purpose of these observations is to observe compliance with the design concepts, specifications, or recommendations and to allow design changes or evaluation of appr�priate construction measures in the event that subsurface conditions differ from those anticipated prior to the start�f construction. LIMITATION We completed this work in accordance with our proposal dated February 26, 2014. �ur report is for the exclusive use of Seco Development and their design consultants for specific application to the � 19014-02 u April 18,2014 �T�Qw�� Southport Hotel � 13 subject project and site. We completed this study in accordance with generally accepted geotechnical practices for the nature and conditions of the work completed in the same or similar localities,at the time the work was performed. We make no other warranty,express or implied. We trust that this report meets your needs. If you have questions or if we can be of further assistance, please call at your earliest convenience. 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J,."^'�� y _ ``\ , "q; ^ . � ` r\ ] �- � � , / �.� .� -<<_ � � o � � Note:Base map prepared from electronic file entitled,"99323BRH.dwg" Exploration Location and Numbef provided by Bush,Roed,&Hitchings dated September 6,2000. A A� S� Borin conducted b Hart Crowser,2000 A roximate location Cross Section Location 0 HC-1 9 Y � pp ) � _�� _ _ _ 0 100 200 and Designation � B-1 Boring conducted by others(Approximate location) SCale in Feet CPT Test conducted by others(Approximate location) 19014-02 4N4 O CPT-1 Approximate Construction Limits Figure 2 This page is intentionally left blank for double-sided printing. Generalized Subsurface Cross Section A-A ' Southport � w .>-. N j N O � > '� > r L(� O � N �'' C'v � I � t j a U a�'p a � A m = U = " A' 0 , -- - - - - - - - - - , . - - - - - - - - - - - - - - - - �- - - - - - - - - - - -- _ / Loose to medium dense, 15 Very loose to loose, �� clean to slightly silty SAND slightly silty SAND 30 �� — �/ Medium stiff SILT and _ � _ _ � sandy SILT �— � � — � — ? 45 � � ' � � � - - - - - - - - - ?� ____ — \� ; ,;-> . ' Medium dense to dense, � \ 60 ` �� ,>�';F , slightly sifty SAND �kj�,��j'i�`��x �� a°�i 'J� ' � � � 75 . _ � �_ ,� �- - - - - - - -- - - - - - —_ � \ y ? —\ ` - - - - - - — _ / - - - -- - - - - - - - - - - - - — �H�rd�an yd S1LT �� 90 Dense ilty � � Dense SAND � � � � � SAND � � _ _ - - - - - - �- - - - - - - - - -� � ��? � _ _ 0 105 � — � ` � w � L �� o Soft to medium stiff, �? 120 and stiff SILT and CLAY � � � — � 135 - - - - - - — � - - - - - - � - - - -?— _" ____ — ._ - -�- - - - - - --9—_ � Dense to very dense, silty SAND � 150 Notes: Contacts between soil units are based upon i�terpolation between borings and represent our interpretation of subsur(ace conditions based on currently available data. The ground surface elevation of all explorations is between 20 and 24 feet. None of the�ocations or e�evations have been surveyed. B-1 (40'W) Exploration Number(Offset Distance and Direction) Horizontal Scale in Feet Exploration Location 0 80 160 = ATD 0 30 60 � ❑ =Liquefiable Material Water Level at Time of Drilling Vertical Scale in Feet � � = Bearing Unit � ❑ = Cohesive Material underlying Bearing Unit `r � ` �� __�__ Inferred Geologic Contact(Major Unit) 19014-02 4/14 Figure 3 , This page is intentionally left blank for double-sided printing. Generalized Subsurface Cross Section B-B' Southport z z �n � cn ' z o Z o v o o � � C � o c� � � N � , � H B m = m = c.a.> m B• o �_�� ---- ------ ------------------------------------------- -------- --- ;--- — --------Z— ---------------- , . ,— �� Loose to medium dense, 15 �� slightly silty SAND Very loose to loose, �� slightlysiltySAND �' -------------- -------------- = 30 ______-- -- MediumstiffSlLTandsandySlLT _____ _______ —'---_____ 45 �—'-- __,�—' . ---____ ---___ �— — ' — - � ?� — ---------------------- --- tr Medium dense to dense, ———_ ' "" " slightly silty SAND �y — � 60 — � � � , ��. _ ,�.�> , x�.-_a:r_�,�..�� ., ` , , �- ,� ' _ . ;�?�?S?�Z',?lJ?�5�;� � � ^�, ., . , m U N7`J ''`\_ .... _ . .. . � � �___-__ ---------___�___.�-==�� ____ �_-_--_'_�_�_____ ��__ -, . .=. .. .. - . O90 �� _��i/ -=___`___'?-�__._.._._----�� -__�- -�-�__ ��_ � SAND �� \ Dense to very dense SAND ��.Q` �� o i --__ �` '~ i '---- --- �� a105 �� ---------------- �� ? m ? ? — � -- ----------------.--�---- 120 Very soft to medium stiff, -----_ �___ _____ _____________ andstiffSlLTandCLAY `�--_�_ � 135 --- ---- DensetoverydenseSAND —'--------------- ----------�------- 150 _—_-- ? -------- -----_ � Notes: Contacts between soil units are based upon interpolation between borings and represent our interpretation of subsurface conditions based on currently available B-1 (60� N� Exploration Number(Offset Distance and Direction) data. � The ground surface elevation of all explorations is between 20 and 24 feet. None of EX loration Location " the locations or elevations have been surveyed. p Horizontal Scale in Feet ATD 0 80 160 � Water Level at Time of Drilling = ❑ 0 30 60 = Liquefiable Material Vertical Scale in Feet �� f - '� ❑ = Bearing Unit rn ❑ =Cohesive Material underlying Bearing Unit ��0��, 19014-02 4/14 ___�___ Inferred Geologic Contact(Major Unit) Figure 4 This page is intentionally left blank for double-sided printin�. Laterally Loaded Piles in Elastic Subgrade Deflection and Moment Criteria Fixed-Headed Pile Condition , (a) Deflection and Moment Coefficients ', Defiection Coefficient,AY I -0.2 0 0.2 0.4 0.6 0.8 1.0 1.1 I 0 I, i T ' � , Q 2T p- � ' 0 � / 3T 3 4T 4 Moment Coefficient,Am -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0 _ � - _ � � � ,� T � � � � D=2`� \ Q 2T a� � � 3 3T 4T 4 (b) Typical Deflection and Moment Curves X PXX _ _ _ _ Y _ _m_ P,� Pile Shear at Ground Surface or Mudline T Relative Stiffness Factor D �/ LOAD DEFLECTION MOMENT �� H.N�TCItOwS[R 19014-DO 4/94 Figure 5 HCS/Fix Head.cdr i This page is intentionally left blank for double-sided printing. Laterally Loaded Piles in E/astic Subgrade Deflection and Moment Criteria Free-Headed Pile Condifion (a) Deflection and Moment Coefficients Deflection Coefficient,Ay Moment Coefficient,Am -1 0 1 2 3 -0.1 0 0.2 0.4 0.6 0.8 1.0 0 � 0 i •i i ✓�� T T D=2 D=2 s T T � QL ��i••••• I 0 2T p 2T � � , I � � i 3T 3 , 3T �3� ' � . 4.�' 4 I', 4T 4T 5 5 Deflection Coefficient, B Moment Coefficient, Bm -1 0 1 Y 2 3 -0.1 0 0.2 0.4 0.6 0.8 1.0 � ,-- , 0 ; , � I � '� i T D=2 f•. T D=2 � T ' T � L L i I 0 2T / 0 2T � 31 3 i� I � � 3T , 3T I / � � � 4 & 5 , ' 4T 4T I 5 , PXx Pile Shear at Ground Surface or Mudline (b) Typical Deflection and Moment Curves M� Pile Moment at Ground Surface DEFLECTION MOMENT P �� Y � m T Relative Stiffness Factor —► � X - - — - — - — - - c �,' E a:f- �/ v �j ;� f�iu�rGr�Owsr-r� � 19014-00 4/14 Figure 6 . HCS/Free Head.cdr . . . This page is intentionally left blank for double-sided printing. APPENDIX A Field Expiorations Methods and Analysis .� /i 19014-02 �'��w�R April 18,2014 This page is intentionally left blank for double-sided printing. APPENDIX A FIELD EXPLORATIONS METHODS AND ANALYSIS This appendix documents the processes Hart Crowser used to determine the nature of the soils underlying the project site addressed by this report. The discussion includes information on the following subjects: ■ Explorations and Their Location ■ The Use of Auger Borings ■ Standard Penetration Test(SPT) Procedures ■ Use of Shelby Tubes Explorations and Their Location Subsurface explorations for this project include two borings, HC-1 and HC-2. The exploration logs within this appendix show our interpretation of the drilling, sampling,and testing data. They indicate the depth where the soils change. Note that the change may be gradual. In the field,we classified the samples taken from the explorations according to the methods presented on Figure A-1-Keyto Exploration Logs. This figure also provides a legend explaining the symbols and abbreviations used in the logs. Location of Explorati�ns. Figure 2 shows the location of explorations, located by hand taping or pacing from existing physical features. The ground surface elevations at these locations are between 20 and 24 feet,and were interpreted fr�m elevations shown on base map provided by Bush, Roed and Hitchings,dated September 6, 2000. The method used determines the accuracy of the location and elevation of the explorations. The Use of Auger Borings With depths ranging from 129 to 149 feet below the ground surface,two hollow-stem auger and/or mud rotary borings,designated HC-1 and HC-2,were drilled from September 18 to 20, 2000. The borings used a 3-3/8-inch inside diameter hollow-stem auger and were advanced with a truck- mounted drill rig subcontracted by Hart Crowser. The drilling was continuously observed by an engineering geologist from Hart Crowser. Detailed field logs were prepared�f each boring. Using the Standard Penetration Test(SPT)and thin-walled Shelby tubes,we obtained samples at 2-1/2-to 5- foot-depth intervals. NOTE: Boring HC-1 and the latter portion of boring HC-2 were advanced using mud rotary technique. The borings logs are presented on Figures A-2 and A-3 at the end of this appendix. � i! 19014-02 �{/�/�'�H/S(J; April 18,2014 A-2 I Southport Hotel Standard Penetration Test (SPT) Procedures This test is an approximate measure of soil density and consistency. To be useful,the results must be used with engineering judgment in conjunction with other tests. The SPT(as described in ASTM D 1587)was used to obtain disturbed samples. This test employs a standard 2-inch outside diameter split-spoon sampler. Using a 140-pound hammer,free-falling 30 inches,the sampler is driven into the soil for 18 inches. The number of blows required to drive the sampler the last 12 inches onlv is the Standard Penetration Resistance. This resistance,or blow count, measures the relative density of granular soils and the consistency of cohesive soils. The blow counts are plotted on the boring logs at their respective sample depths. I S�il samples are recovered from the split-barrel sampler,field classified,and placed into water tight jars. They are then taken to Hart Crowser's laboratory for further testing. In the Event of Hard Driving �ccasionally very dense materials preclude driving the total 18-inch sample. When this happens,the penetration resistance is entered on logs as follows: Penetration less than six inches. The log indicates the total number of blows over the number of inches of penetration. Penetration greater than six inches. The blow count noted on the log is the sum of the total number of blows completed after the first six inches of penetration. This sum is expressed over the number of inches driven that exceed the first 6 inches. The number of blows needed to drive the first six inches are not reported. For example,a blow count series of 12 blows for 6 inches,30 blows for 6 inches, and 50(the maximum number of blows counted within a 6-inch increment for SPT)for 3 inches would be recorded as 80/9. Use of Shelby Tubes To obtain a relatively undisturbed sample for classification and testing in fine-grain soils,a 3-inch- diameter thin-walled steel (Shelby)tube sampler was pushed hydraulically below the auger. The tubes were sealed in the field and taken to our laboratory for extrusion and classification. L:\Jobs\1901402\Design Report\Geotechnical Engineering Design Report.docx R 19014-02 /� April 18,2014 �r�� Key fo Exploration Logs Sample Description Classification of soils in this report is based on visual field and laboratory — observations which include density/consistency,moisture condition,grain size,and MOlstUl'e plasticity estimates and should not be construed to imply field nor laboratory testing Dry Little perceptible moisture unless presented herein.Visual-manual classification methods of ASTM D 2488 Damp Some perceptible moisture,likely below optimum were used as an identification guide. Moist Likely near optimum moisture content ', Soil descriptions consist of the following: Wet Much perceptible moisture,likely above optimum Density/consistency,moisture,color,minor constituents,MAJOR CONSTITUENT, additional remarks. Densi /Consistenc Minor Constituents Estimated Percentage tY Y Trace <5 Soil density/consistency in borings is related primarily to the Standard Slightly(clayey,silty,etc.) 5 - 12 Penetration Resistance.Soil density/consistency in test pits and probes is Clayey,silty,sandy, gravelly 12 - 30 estimated based on visual observation and is presented parenthetically on the loqs. Standard Standard �proximate Very(clayey,silty,etc.) 30 - 50 Si4ND or GRAVEL penetration SILT or CLAY penetration S ear Strength Density Resistance(N) ConsistenCy Resistance(N) in TSF in BlowslFoot in Blows/Foot Laboratory Test Symbols Very loose 0 to 4 Very soft 0 to 2 <0.125 Loose 4 to 10 Soft 2 to 4 0.125 to 0.25 GS Grain Size Classification Medium dense 10 to 30 Medium stiff 4 to 8 0.25 to 0.5 CN Consolidation Dense 30 to 50 Stiff 8 to 15 0.5 to 1.0 UU Unconsolidated Undrained Triaxial Very dense >50 Very stiff 15 to 30 1.0 to 2.0 CU Consolidated Undrained Triaxial Hard >30 >2.0 CD Consolidated Drained Triaxial QU Unconfined Compression Sampling Test Symbols �s Direct Shear K Permeability � 1.5"I.D.Split Spoon � Grab(Jar) ❑ 3.0"I.D.Split Spoon pp Pocket Penetrometer I�i m Shelby Tube(Pushed) � Bag Approximate Compressive Strength in TSF N Torvane � Cuttings Q Core Run Approximate Shear Strength in TSF CBR California Bearing Ratio SOIL CLASSIFICATION CHART MD Moisture Density Relationship SYMBOLS TYPICAL AL Atterberg Limits MA.IOR DIVISI�NS GRAPH LETTER DESCRIPTIONS � �� Water Content in Percent CLEAN W��EDGRAVELS,GRAVEL- I I ` Liquid Limit I GRAVEL GRAVELS �,� � Gw FNESM11�URES,LfTTLEORNO � Natural I AND Plastic Limit GRAVELLY POORLYGRADEDGRAVELS, � ' $��L$ (lfTTIEORNOFINES) 0�� Gp GRAVEL-SlWDA7IXTURES.LITTLE PID Photoionization Detector Reading �� OR NO FINES COARSE CA Chemical Analysis GR,4INED GRAVELS WITH o o GM SILNGRAVELS.GRAVEL-SAN�- DT In Situ Densit in PCF SOILS ��=rH^N soq F WES SILT A7pTURES Y �FRA�CT^ION OT Tests by Others RETAINED ON NO. 45EVE (hPPRECl4BLE G.`. CLAVEYGRAVELS,GRAVEL-SAND- AMOUNT OF FMIES) CLAV MU(TURES . . Groundwater Indicators � SAND CLEAN SANOS .�.��- -� WELL-GRADED SANDS,GRAVELLY ��oRerHnr�so% Sw SANDS,LfTTLEOF2NOFNES � Groundwater Level on Date oF MnreRw�5 AND �-• ��•- . LARGERTIIAN SANDY , or(ATD)At Time of Drilling NO.200 SEYE SOILS � POORLVGRADED SlWDS, S¢E (LfRLE OR NO FINES) SP GRAVEILY SAND,LfTRE Oft NO FINES � Groundwater Seepage SANDS WITH SLTYSANOS,SAND-SLT (Test Pits) MORETHAN50% FINES 'SM MDCfURES OF CMRSE fRACT10N PASSING ON NO. 4 SIEVE AMOI/N EOF FBINES) S�+' MIXR�R�NDS,SAND-CLAY Sample Key INORGANIC SILTS AND VERY FINE ML �DS.ROCK FLOUR,SILTY OR CLAVEV FINE SANDS OR CLAYEV Sample Type Sample Recovery SlTS W RH SLIGHT PUS71CfTV `t SILTS INORGANIC CLAYS OF LOW TO ^ FINE AND ��ITMAN� `.L MEDIUMPLASTICfTV,GRAVELLV 12 GRAINED CLAYS CLAVS,SANDVCIAVS,SLT'CLAYS, a SOILS LenN CL,�vs S-� 23 50/3" o =_ �L ORGANIC SLTS AND ORGANIC SILTY Sample � � — cuvs oF�ow ausr�cm Number B�� a — — �6 inches � MORE THAN 50% � ' � OF MA7ERIAL IS NORGJINIC SILTS,MICACEOUS OR � � MH DIATOMACEOUS FME SAN�OR UI SMALLERTHA!� SILTYSOLS = N0.200SIEVE a SIZE SILTS LIOUID LMIT NORGANIC CLAVS OF HMaH � � CLAYS GREATER THAN 50 CH p�qSTICRy � O �/'�� r/� � ORGANIC CLAlS OF MEDUM TO II Y�Y`� �rI\O��I, � - - OH HIGH PLASTICRY,ORGANIC SILTS w J-7452 10/00 W ,,, HIGHLY ORGANIC SOILS PT PEA�,HUMUS,SWAMP SOLS WRH � ,I, HIGH ORGANIC CON7EIJTS Figure A-1 � Y W Y NOTE�DUALSYMBOLSAREUSEDTOINDICATE80RDERLINESOILCLASSIFICATIONS � This page is intentionally left blank for clouble-sided printing. Boring Log HC-1 STANDARD PENETRATION LAB Soil Descriptions �pth RESISTANCE TESTS in Feet Sample • glows per Foot Approximate Ground SurFace Elevation in Feet: i 2 5 �0 20 50 ioo Brown,slightly silty,gravelly,fine to � � medium SAND over medium dense,wet, brown-gray,slightly gravelly SAND. � S-1 • 5 ATD Loose,wet,gray,silty,fine SAND. S2 Loose,wet,black,gravelly SAND. �� i i S-3 • GS � i 15 I Loose to medium dense,wet,dark gray, I � non-gravelly to slightly gravelly,fine to � medium SAND. S� • I, 20 I S-5 • 25 Slightly silty. S-6 GS 30 , S7 � 35 Medium dense,wet,dark gray,slightly silty,gravelly SAND. �8 • GS Medium stiff to stiff,wet,dark gray to gray, 40 fine,sandy SILT. S-9 45 v � 5-10 � 50 's-11 o Medium dense,wet,gray,silty,fine SAND i � with trace organic material. o .512 U I = 55 S-13 a' i o Medium stiff,wet,dark gray,slightly fine � � sandy SILT. S-�a � 6� S-15 0 � Medium dense to dense,wet,gray,silty to S-16 • z slightly silty,fine to medium SAND. � 0 m 65 1 2 5 10 20 50 100 • Water Content in Percent �/ �r 17/U[I�.I�DIIJYI 1.Refer to Figure A-1 for explanation of descriptions and symbols. 2.Soil descriptions and stratum lines are interpretive and actual changes 19014-02 09/QQ may be gradual. Fl ure A-2 1/2 3.Groundwater level,'rf indicated,is at time of dri�ling(ATD)or for date g specified. Level may vary with time. Boring Log NC-1 STANDARD PENETRATION �qg �p� RESISTANCE TESTS Soil Descriptions in Feet Sample • Blows per Foot Approximate Ground Surface Elevation in Feet: � 2 5 10 20 50 100 Medium dense to dense,wet,gray,silty to 65 slightly silty,fine to medium SAND. 5-17 • 70 �s-is 75 Stratified layers of organic material. �19 80 S-2o • Very stiff to hard,wet,gray,non-sandy to 85 fine to medium sandy SILT. 5-21 AL 90 �pp 5-23 95 `S-24 Medium stiff to hard,wet,light gray CLAY. 100 5-25 AL 105 S26 110 5-27 AL,CN S-28 0 � a 115 � 0 c? o S-29 U I = Trace fine sand and gravel. 120 'a c7 N 5-30 AL � Trace fine sand. � 125 �I 0 J � � 5-31 °m Bottom of Boring at 129.0 Feet. �30 � Completed 09/20/00. � 2 5 �0 20 50 �oo • Water Content in Percent f/ �, Tl/.LZ/�./SO�IJY\ 1.Refer to Figure A-1 for explanation of descriptions and symbols. �9014-OZ �9/�0 2.Soil descriptions and stratum lines are interpretive and actual changes may be gradual. 3.Groundwater level,if indicated,is at time of drilling(ATD)or for date Figure A-2 2/2 specified. Level may vary with time. Boring Log HC-2 STANDARD PENETRATION LAB Soil Descriptions oepm RESISTANCE TESTS in Feet �m� � g�p��r Foot Approximate Ground Surface Elevation in Feet: � 2 5 10 20 50 100 IMPORT FILL. � Very loose,moist,brown and gray,slightly gravelly,silty,fine to medium SAND with �� interbedded silt. Organic silt and fibrous peat within sampler 5 � shoe. ,� Loose to dense,wet,gray,non-siity to —J ATD slightly silty,fine to medium SAND with �2 � trace scattered gravel. 10 Grading to less silty. S-3 • GS I 15 S-4 � I Trace wood fragments. 20 1.5 feet of heave observed. S-5 GS 25 Stiff,wet,gray,fine,sandy SILT,thinly laminated. 1.5 feet of heave observed. � � ----- --- 30 Soft,wet,gray SILT,thinly laminated. S7 35 Abundant organic material noted. �g 40 i S-9 Medium dense,wet,gray,slighUy silty,fine i to medium SAND. 45 I a 2.5 feet of heave observed. ^ 5-10 • �6. a Interbedded silt zones and organic material 50 ' � noted. o �-------------------� � Very dense,wet,gray,slightly silty to silty, o fine SAND. g_�� 1.5 feet of heave observed. = 55 � 4 feet of heave observed. N 5-12 • �5. � A Medium dense to dense,wet,gray,slightly 60 o silty to silty,fine SAND. J � Z S-�3 • � O m 65 1 2 5 10 20 50 �oo • Water Content in Percent �/ �r �l/.{/tl Vi�1IJ/:/1 1.Refer to Figure A-1 for explanation of descriptions and symbols. 2.Soil descriptions and stratum lines are interpretive and actual changes 19014-02 09/QQ may be gradual. 3.Groundwater level,if indicated,is at time of drilling(ATD)or for date Figure A-3 �/3 specified. Level may vary with time. Boring Log HC-2 STANDARD PENETRATION �qg �P� RESISTANCE TESTS Soil Descriptions in Feet Sample . aiows per Fooc Approximate Ground Surface Elevation in Feet: � p 5 10 20 50 100 Medium dense to dense,wet,gray,slightly 65 silty to silty,fine SAND. S-14 70 Lamination of organic materiai noted. �15 ' 75 S-�6 Silt zones and 1-inch organic layer.(PEAT) Medium stiff to stiff,moist,gray,slightly $� fine to medium sandy to non-sandy SILT. S-17 AL 85 A Dense to very dense,moist,gray,silty to �18 B • very silty,fine to medium SAND. 90 S19 • 95 Abundandt organic material(shell �� ' fragments)noted. 100 Very soft,wet,gray,slightly sandy to non-sandy SILT. 5-21 AL , 105 `S-216 110 Very soft,wet,gray CLAY. 5-22 � � S-226 AL,CN o Very soft to very stiff,wet,gray SILT. �15 5-23 c� a O 5-24 • U _ �20 a c� N S-25 AL v ^ 125 o Medium stiff to very stiff,wet,gray,slightly � fine to medium sandy SILT. ? S-26 � o � m 130 1 2 5 10 20 50 10� • Water Content in Percent �/ �r '7/.V[l�.I1�II.7Yl 1.Refer to Figure A-1 for explanation of descriptions and symbols. 19��4-02 2.Soil desaiptions and stratum lines are interpretive and actual changes �9/00 may be gradual. 3.Groundwater level,if indicated,is at time of drilling(ATD)or for date Figure A-3 2/3 specified. Level may vary with time. Boring Log HC-2 STANDARD PENETRATION �p,g Depth RESISTANCE TESTS Soil Descriptions in Feet Approximate Ground Surface Elevation in Feet: sample . Blows per Foot 1� 1 2 5 t0 20 50 100 Medium s6ff to very stiff,wet,gray,slightly fine to medium sandy SILT. 5-27 • 135 Very loose,wet,gray,silty,fine to medium S-2a • ' SAND. 140 Dense to very dense,wet,gray,slightly gravelly,fine to medium SAND. 5-29 • 145 �S-� I Bottom of Boring at 149.0 Feet. �� Completed 09/18/00. 155 160 165 i 170 175 0 n � �80 O U'. K O U� _ ��J a' c� 8 � � 190 0 J � Z � � 00 195 7 2 5 10 20 50 100 • Water ConteM in Percent « �t II.7Yl 1.Refer to Figure A-1 for explanation of descriptions and symbols. �9D�4-�Z 2.Soil descriptions and stratum lines are interpretive and actual changes �9/�0 may be gradual. FI ure A-3 3/3 3.Groundwater level,if indicated,is at time of drilling(ATD)or for date g specified. Level may vary with time. This page is intentionally left blank for double-sided printing. APPENDIX B Laboratory Testing Program .� � 19014-02 /�{/�/Z'l'�Q�I�/$(J; April 18,2014 This page is intentionally left blank for double-sided printing. APPENDIX B � LABORATORY TESTING PROGRAM A laboratory testing program was performed for this study to evaluate the basic index and geotechnical engineering properties of the site soils. Both disturbed and relatively undisturbed samples were tested. The tests performed and the procedures followed are outlined below. Soil Classification Field Observation and Laboratory Analysis. Soil samples from the explorations were visually classified in the field and then taken to our laboratory where the classifications were verified in a relatively controlled laboratory environment. Field and laboratory observations include density/consistency, moisture condition, and grain size and plasticity estimates. The classifications of selected samples were checked by laboratory tests such as Atterberg limits determinations and grain size analyses. Classifications were made in general accordance with the Unified Soil Classification (USC)System,ASTM D 2487,as presented on Figure B-1. Water Content Determinations 'I Water contents were determined for most samples recovered in the explorations in general accordance with ASTM D 2216,as soon as possible following their arrival in our laboratory. Water I contents were not determined for very small samples nor samples where large gravel contents would result in values considered unrepresentative. The results of these tests are plotted at the respective sample depth on the exploration logs. In addition,water contents are routinely determined for samples subjected to�ther testing. These are also presented on the exploration logs. ' Grain Size Analysis (GS) Grain size distribution was analyzed on representative samples in general accordance with ASTM D 422. Wet sieve analysis was used to determine the size distribution greater than the U.S. No. 200 mesh sieve. The results of the tests are presented as curves on Figures B-2 and B-3 plotting percent finer by weight versus grain size. Atterberg Limits (AL) We determined Atterberg limits for selected fine-grained soil samples. The liquid limit and plastic limit were determined in general accordance with ASTM D 4318-84. The results of the Atterberg limits analyses and the plasticity characteristics are summarized in the Liquid and Plastic Limits Test Report, Figures B-4 through B-7. This relates the plasticity index(liquid limit minus the plastic limit)to the liquid limit. The results of the Atterberg limits tests are shown graphically on the boring logs as well as where applicable on figures presenting various other test results. � I'� 1,I 19014-02 �{/�r(�Q�Jj April 18,2014 �, A-2 I Southport Hotel Consolidation Test (CN) : The one-dimensional consolidation test provides data for estimating settlement. The test was performed in general accordance with ASTM D 2435. A relatively undisturbed,fine-grained sample was carefully trimmed and fit into a rigid ring with porous stones placed on the top and bottom of the sample to allow drainage. Vertical loads were then applied incrementally to the sample in such a way that the sample was allowed to consolidate under each load increment. Measurements were made of the compression of the sample(with time) under each load increment. Rebound was measured during the unloading phase. In general,each load was left in place until the completion of 100 percent primary consolidation, as computed using Taylor's square root of time method. The next load increment was applied soon after attaining 100 percent primary consolidation. For selected tests, I�ads were left in-place for as long as 24 hours to record secondary consolidation characteristics. The test results plotted in terms of axial strain and coefficient of consolidation versus applied load (stress) are presented on Figures 6-8 and B-9. L:\Jobs\1901402\Design Report\Geotechnical Engineering Design Report.docx � � 19014-02 � April 18,2014 ��Q� l Unified Soil C/assificafion (USC) Sysfem Soil Grain Size � _ _ ._ - - --- -- � Number ol Mesh per Inch S�ze ot Opening In Inches � (US Slandard) Grain Size m M�.hmetres �� ^' �D O N^� � c7�n N .�- c'%f e � N Q �O � N O � O ..7 O O O H O S O ' i ; i I I f iI ' I � i i � i 8 N O � �O C � N O aD �D O ;'f N — m �O O f� N O O O O O � � C O O x O � ^ O Grain Size in Mdlimetres COBBLES � GRAVEL SAND SILT and CLAY � Coarse-Grained So�is � Fine-Grained Soi�s , Coarse-Grained Soils - - , -- - - -- - _ __ _ _ _ G W � G P � G M G C ; S W S P : S M S C �*� } - ---�*�--_-- -- Clean GRAVEL <5%6nes � GRAVEL v�nm >12%fines Clean SANO <5'�tmes SANC w��h >12%fines ! GRAVEL >50%coarse fraction larger than No 4 SANO >50%coarse fraction smaller than No a Coarse-Graned So�ls >5096 larger than No 200 sieve L- ---- . ______ _ __ _ . .. -__ ___ — ._. . .. ..__ —' __. . `�D��.>4 for G W ;'(D�Z G W and S W !—� 8 1< ': <3 G P and S P Ctean GRAVEL or SAND not meet�ng ',.D,o,>6 for S W �O,o X D�; requirements for G W and S V'! G M and S M Atterberg limits below A line with PI <4 G C and S C Atterberg limrts above A Line w�th PI >7 * Coarse-grained soils with percentage of fines between 5 and 12 are considered borderline cases required use of dual symbo:s � D.�, D�, and De1i are the particles diameter of wh�ch �U. 30, and 60 percent, respec��ve�y, of the soil we�gh;are finer Fine-Grained Soils ' ---- ---- ------ - - -- -- - ---T---- - - — - ML CL OL MH CH OH Pt --_ - - ---- -- -- -- -- -- -- -- SILT C�AY Oryanic SILT CLAY Organic Hignly � - -- Organic � Sods with Liquid Limit �5096 Soils with Liqwd Lim�t >50% � SOils I Fine-Grained Soils >5096 smaller than No 2U0 sieve 60 60 � C H sa x 40 40 a� � C L �re � 30 P`� 3Q � a 20 MHOrOH 20 10 < CL - ML M � io or O L � �0 10 20 30 40 50 60 �0 80 90 100� " S� � L�quid Lir-�.t " � � —_ _ � �/�JL"Ji � y • 0 " J-7452 12/00 Figure B-1 PARTICLE SIZE DISTRIBUTION TEST REPORT � c � ` � 8 _ � � � r 5 S � � : � i �¢ : : 100 � I ` � i 90 ' ' ; i :i ; ; ; : ; 80 : � ' '. ` 76 I � : i � � W Z � Z 5a � �' � • W � C� � W qp � ; : ;i 30 ` i � �: : : : : ; ' I i 'E 20 : : � : , I 10 . , 0 : ': : ` ' ! ' ' 200 100 10 1 0.1 0.01 O.OG1 GRAIN SIZE - mm ,�+ 3.. °�G GRAVEL °�SAND °�6 FINES CRS. FINE CRS. MEDIUM F1NE SILT CLAY � 0.0 0.0 18.4 18.6 44.9 15.2 2.9 ❑ 0.0 0.0 0.0 0.6 42.1 49.6 7.7 0 0.0 0.0 16.8 12.0 45.5 20.2 5.5 LL P1 �85 �60 �50 030 �15 �10 Cc �u � 5.64 1.77 1.21 0.630 0.376 0.295 0.76 5.99 ❑ 0.689 0.440 0.389 0.308 0.223 0.135 1.59 3.25 � 592 1.23 0.871 0.485 0.282 0.199 Q.96 6.16 MATERIAL DESCRtPTION USCS NAT. MOIST. o Gravelly SAND SP 16% G� Slightly silty,medium to fcne SAND SP-SM 31% c: Sli tI siltv, vellv S,4ND SP-SM 16% Remarks: Project: Southport 0 ❑ Client: o o Source: HC-1 Sample No.: S-3 ❑ Source: HC-1 Sample No.: S-6 � � Source: HG1 Sample No.: S-8 A � J-7452 10/4/2000 �T�ON/S� Figure No. B-2 I - PARTICLE SIZE DISTRIBUTION TEST REPORT s r: �i s C s �` c r` o g S 0 g 8 S $ �0 7i = i 1 fi ; i o i Y �� : . : "' � � � � . , I:� � I � � so ` I i eo � . � i � f w � z � ! , ; I u.. ;j : I W s° � � U : � : W qp a j � � i 3o I � I zo I : � I ' i; . �o ' ; , I I i a ; ' '� ` , I ': I , I I i zoo �oo io � o.� o.oi o.00� GRAIN SIZE - mm X GRAVEL X SAND °�6 FINES •�.+3•• CRS. FINE CRS. MEDIUM FINE SILT CLAY � 0.0 0.0 3.1 6.2 40.5 47.3 2.9 ❑ 0.0 0.0 0.4 2.3 3 7.1 52.6 7.6 LL PI �85 �60 �50 �30 015 �10 Cc Cu '� 1.14 0.50� 0.424 0.314 0.238 0.201 0.97 2.51 G 0.762 0.42�1 0.363 0.267 0.177 0.120 !.40 3.52 MATERIAL DESCRIPTtON USCS NAT. MOtST. o SAND SP 23% G Slightly silty,medium to fine SAND SP-SM 21% I Remarks: Project: Southport i 0 o Client: o Source: HC-2 Samp(e No.: S-3 c Sou�ce: HG2 Sample No.: S-5 R V J-7452 10/4/2000 �T�Q�I�/S[f� Figure h'o. B-3 LIQUID AND PLASTIC LlMITS TEST REPORT , � Dashed line indicates the approximate ,' 110 upper limit boundary for natural soils , , — ' i � � 90 O� ' t , � � G o �o I z i � U � H g � � n. � � i � i i ( 3° �i O I � � o, �� ,G�, � � � �; - � - i M�o�o� � MH or ,OH � ' 10 30 50 70 90 110 130 150 170 190 LIQUID LIMIT Location+ Description LL PL PI -200 USCS • Source:fIC-1 Sample No.: S-21 Elastic SILT 119 59 60 MH ■ Source:HC-1 Sample No.: S-25 CLAY 38 22 16 CL • Source:HC-1 Sample No.: S-30 CLAY 38 24 14 CL � emarks: Project: Southporc • ■ • Client: Location: Renton,WR A � J-7452 10/5/2000 ��'�OH/s� Figure No. B-4 LIQUID AND PLASTIC LIMITS T REPOR i EST T � , Dashed line indicates the approximate � upper limit boundary for natural soils so � � 0� ' i O� � ' G� � � . X , � � 2 / � / U � � � g �� I j a � 20 � Q� � Ot ,' G�, I � I � � ' ,o ' � � --- ��//%/ 4 _ � ML or OL MH or OH ! i � i �o so so �o so „o LIQUfD UMIT Location+ Description LL PL PI -200 USCS • Source:HG1 Sample No.: 5-27 Fat CLAY 69 28 41 CH emarks: Projeci: Souchport • Client: Location: Ren[on,WA � V J-7452 9/29/2000 lLYirV[Qw,s[� FigureNo. B-5 LIQUID AND PLASTIC LfMITS TEST REPORT � Dashed line indicates the approximate �� upper limit boundary for natural soils � � 50 � O � ot �' G� �o ' w , • o � Z , � ' U � F- / N a �/ / � / � � O� � '� G�' � 10 , 7 --- ��/"��i/ � � � � 4 _ � ML I r OL � i MH ir OH � ,0 3o so �o so „c �, U�UID LIMIT Location+ Description LL PL PI -200 USCS • Source:HC-2 Sample No.: S-1� Elastic SILT 82 45 37 MH ■ Source:HC-2 Sample No.: 5-21 Elastic SII.T 54 30 24 MH • Sowce:HC-2 Sample No.: S-25 SII.T 38 25 13 MI, emarks: Project: Southport ■ • Client: Location: Renton, WA i � � J-7452 10/5/2000 �T��H/S� Figiue No. B-6 LIQUID AND PLASTIC LIMITS TEST REPORT � Dashed line indicates the approximate �� upper limit boundary fo� naturat soils � � so � C�� i O � � � ' � ' G �o ' w � o � Z � � ' U � � H / � g �' a � 20 � 0� /� O� , � �� G�' � ,o 7 --- � i � ; f I ��'��' ML or OL MH or OH 4 - , � � I ,o � � �o � „a LiQUID LIMIT Locatio�� Description LL PL PI -200 USCS • Source:HC-2 Sample No.: S-22b Fat CLAY 54 25 29 CH emarks: Project: Southport • Client: Location: Renton,WA �� A � J-7452 9/22/2000 �{/�T�ON/S� Figure No. 8-7 CONSOLIDATION TEST RESULTS Stress (tons/ft2) 1/32 1/16 1/8 1/4 1/2 1 2 4 8 16 32 0.00 i � � , � � I 0.05 � 0.10 c .� :. u� I X � ' Q 0.15 ' � � � � I � � ' i � I I o.zo � � i � I I � ' j 0.25 ' � 0.00 � , � ; � � i N o.20 ' 0 o.ao � .m � , 0 o.so N � v 0.80 � I � 1.00 w a� U 1•2O Expi. Sample Depth W.C. % Atterber Limit Wet Wt USC Description No. No. (ft) Before After LL PL PI ( cf) HC-t S-27 109'-1 11' S7% 47% 69 28 41 1 10 cf CH Fat CLAY Remarks: i �� L/ � J-7452 9/29r'2000 � i - Figure B-3 � CONSOLIDATION TEST RESULTS Stress (tons/ft2) 1/32 1/16 1I8 1/4 1/2 1 2 4 8 16 32 0.00 f 0.05 � , 0.10 c .� � N c9 i X � Q ! Q.15 ( 0.20 � , � � 0.25 > 0.00 ' a I i il Y 0.20 � � = 0 0.40 � '� I � 0.60 I o t I �y ! � i o.ao �' ° i.00 , � �� , v 1.20 ' '� Expl. Sampie Depth W.C. % Atterber Limit Wet Wt USC Description No. No. (ft) Before After LL PL PI ( cf) HC-2 S-22b 12.5'-115. 56% 4096 54 25 29 1 10 cf CH Fat CLAY 'Remarks: �� LI y,.� J-7452 9/21/2000 ' - /z�� Figure B-9 i This page is intentionally left blank for double-sided printing. i I APPENDIX C Exploration Logs Completed by Geotech Consultants, Inc. 1999 C�� /i 19014-02 �]'(]�QN/�/j April 18,2014 This page is intentionally left blank for double-sided printing. ` �� , Fe- E - - - -•- - - - _ �Qe��r `�,�ab�� Q�( r�o-�c` ��'� Description Gravei Dark brown, gravelly SAND, fine- to medium-grained, moist, loose Z - becomes wet 5 5 � � SP 10 � � 1 2 � �(SM Dark gray, silty SAND, fine- to medium-grained, wet, very loose � I� I III ' ' ' ! i� j Light gray SILT, low plasticity, wet, very loose li � 15 � 3 � ML ' � - becomes gray-green l� ;�, , . � � Light gray, gravelly SAND, medium- to coarse grained, wet, loose 20 8 � � ,�� SP 6 5 � 30 4 6 � - be�omes very (oose � � ; � ; � � ' ' Light gray to brown, siightiy sandy SILT, low plasticity, wet, very toose 35 2 � � �il� � � ML I � � � 40 � i� i BORING � IS CONTINUED ON NEXT PAGE, PLA7"E 4 BORING LOG �_ � G �O T E C H 1101 LaKe Washington Bo+�levard North con'SUL�rArrrs, wc. � Renton, Washington �� _ Job: Date: Logged by: P/afe: �--�—�--- g9D37 February 1999 SES 3 J-7452 12,'00 Figure C-1 1 J'4 . o�'•`��, b��`� `o��cF� �`� � _ �Q�y �,�d�° � 4 �aF' v5� Description 4 8 � Dark gray SAND, medium-grained, wet, very lccse SP 45 2 g � - contains some silt layers � � � �' � I Li ht ra silt SAND fine- to medium- rained wet, medium- 50 M=29.oi 25 10� � (�� 9 9 Y, Y , 9 , dense ; � sM i � : � � i � ' j , i! i � il 55 ZS 11 � DarK gray SANO, fine- to medium-grained, wet, medium-dense SP 60 , M=21.9% 20 12� I � � I ��ght gray, silty SAND with interbedded silt layers, fine- to medi�,�m- ; ; i � grained, wet, medium-dense � i i I � i 65 19 13'� , ; � 1 � � �i; ( � SM 7� M=43.1% 2 14� , � i - becomes very laose i � I ; � � I � I 75 15 15� I � � � , i� f i ; ; , i $o BOR/NG 1 1S CONTlNUED O!J NEXl PAGE, PLATE 5 BORING LOG ..� � G E O T�C H 110 i Lake Washington Boulevard Nor�h C:UNSUL'1'AN'I'5, iNc. Renton, Washington � � � Job: Date: Logged by: Plafe: y� '�—� 99037 Februar� 1999 SES 4 J-7452 12/00 Figure C-1 2/4 o� [�VI�CIfVV �1 GUril�rllJeQ .' �yQ��S.�� vlb`'��`� `a,� ��F� �Q�e G5 , Q� ,�a � Q 5d J5 Description 2 16 �� Light gray SILT, low plasticity, wet, very loose M� � � ,i I I SM i Light gray, silty SAND interbedded with silt layers, fine- to medium- 85 � grained, wet, medium-dense j 25 ,7B :�!� ;� , j � i Bluish-gray SILT, low plasticity, wet, medium-dense I ML � �'lil' � � 90 I ' 25 18 ' �I� �� ght gray, siity SAND interbedded with sand layers, fine- to medium- I �;! grained, wet, medium-dense I '� i �� I� �, 95 33 19 � SMI� - becomes dense � �� 'i Ijll • ; � I 100 2 2p , � i I 1; - becomes very loose � i (I�; � Light gray, clayey SILT, medium-plas2icity, wet, soft j ► � � � �s .� � �i z 2, � , I � . � � � ML � � � I � � 110 � �Ii � i 2 22� i� � - sand lenses noted � i�� i I� '� i, , �; i SP L�ght gray GRAVE�, wet, very loose 115 4 2 3� �a, i �!'(� '; Light gray, clayey SILT, low plasticity, wet, soft � I ML , , � ili��;l 120 BORlIVG 1 !S CONT/NUED ON NEXT PAGE, PLATE 6 B�RING LOG 4 � G �O T�C H 1101 Lake Washington Boulevard North CONStiL1'A^1'1'S, INC. � Renton, Washington ', , � Job: Date: Logged by: Plate: ��— 99037 FeSruarv 1999 SES 5 J-7452 12/00 � Flgure C-1 3/4 . �� J5 ��- uv� ��V � �..v� �� ucu C`��j�` �C" `E .0`' 2l ��` � _ �'Qe� `',�a'° � Q 5a`� �5C Descripiion 2 24� ' I �I � Light gray, slightly dayey SILT, low piasticity, we:, soft ;�� ' I ; , , I �� I ML � 125 !�i ( � M=43.5% 2 25� :jII, � il : � �i i � I � � Light gray, slightly silty SAND, fine-grained, wet, medium-dense to d��se 1 �I , � 3Q M=13.4% 56 26 ( � i� � If� � � � i � If I ' 135 ' ; 19 27� � I� ) i ij, � I � ' sP I � s nn i 140 34 28 8 ' � - becomes fine- to medium-grained j � i � � I I � ) I : � 145 55 29� �' � � I i - becomes vAry der,se I � i � I !� , i � 150 � 50 30� ; j � : � � � ' Test boring was terminated at 151.5 feet during drifiing on February 16 8 1�, 1999. ' Groundwater seepage was encountered at 3 feet during drilling. 155 160 BORING LOG � � G E O T E C H 1101 Lake Washington Boufevard Nor�h �c�;vsv�.�r.A1r-�:�, crvc. Renton, Washington � �, � Job: Oate: Logged by: Plate: 99037 Feoruarv 1999 SES E J-7452 12%00 Figure C-1 4,4 t � oo� d V r"C I i V V L E�� o-`��.e �,�� Q� � ��y `�,�o-�° � Q c�afi �5�' Description Grave► over light brown, sandy SlLT with gravel, low plasticity, moist, locse (FILL) FI�L 5 Push 1 � i �I`i�i Dark brown, sandy SILT interbedde� with sand layers, very moist, very ML i loose � , � ;� 'I — il�i� 10 � Light gray SAND with grave(, medium- to coarse grained, wet, loose 4 2 � 15 10 3 ➢ 20 7 4 � 5 4 5 � SP - becomes ine- to medium-grainec+ 30 Push 5 � 35 g 7 � 40 -•-�-•-•- -•-•-•-�-•-•-•-•-•-----•-•-•-•-•-•-•-•-�-•-•-•-•---._._._._._._._._._._._._.....---•---•-�-�-•-._._.. BORlNG Z lS CONTINUED ON NEXT PAGE, PLATE 8 BORI�G LOG .� � G E O T�C H 1101 Lake Washington Boufevard North c:Urv�uL'rA��s, i�vc. � Renton, Washington � Job: Dafe: Logged by: Plate: � \ 99037 Februarv '999 SE5 7 J-7452 12/00 Figure G2 f/3 < � 0p" LJVI \11\V L �rV11�� JGu ��. � �,`v � � \Z, ��`� �,�a'°��`� 4�� c�b�� JSG� Description 11 8 - some gravel noted, medium-dense SP 4� 8 9 � - becomes loose � � � � Light gray, silty SAND interbedded with silt layers, fine- to medium- , SM ' 9�ained, very wet, loose � � � � � � � � 50 2 �� j j Light brownish-gray, slightly sandy SILT, low plasticity, interbedded with M=50.8% i i . , sand layers, wet, very loose � I )� 55 3 11 ' ML � - no sand layers � � � � i �� ;� ; ��, : 60 40 12 � �Ili�� l Light gray SAND, fine- to medium-grained, wet, dense SP 65 2 13� (� II Li ht brownish/ reenish- ra sli htl sand SILT, low lasticit wet, 9 9 9 Y, 9 Y Y P Y� �� very loose , ML ;li''I 70 ; �� 24 �4 � Light gray SAND, fine- ko medium-grained, wet, medium-dense SP � � � i �� 4 15� , ; ; ; � Greenish-gray, slightly sandy SILT, low plasticit,, wet, very loose ML ; �� sM ; Gray, sifty SANQ interbedded with sand layers, fine- to med�um-gra�ned, wet 80 •---•-j- -•-•---�-•-•-•-•-•-•-•-•-•-•-•---._._...-•-�-•-•-•---�-•-•-•-•-•-�-•-•-•-•-•-•-�-•-•-----•---._._.... BORING 2 !S CONTlNUED ON IYEXT PAGE, PLATE 9 BORING LOG � � G E OTE C I-i 1101 Lake Washington Boulevard North CONSUL"['ANI:S, INC. � Renton, Washington � � Job: Date: Logged by: Plate: v----• 99037 Februarv 1999 SES 8 , J-7452 12/00 Figure C-2 2/3 ' � � Q0�' �Vf111VV L 1.V111111UCU �� 6�¢`� �o� e�� Q�� 5 �Q�y `�,�a'� � 4 �o-�' J5G Description M=zs.4^: 41 16 � �� - dense lil !Ii ) Gray, slightly gravelfy SAND, fine- tc medium-grained, wet, very dense 85 84 17' SP 90 18 1 g' ML Light gray, slightly sandy SILT, wet, rnedium-dense ' Test boring was terminated at 91.5 feet during driliing on February 24, 1999. ' Groundwater seepage was encountered at 9 feet during driliing. 95 100 110 115 120 BORING LOG � � G E O T E C H 1101 Lak� Washington Boulevard Ne�h CUNtiUL'1'AiY'1'S, INC. � Renton, Washington � � Job� Date: Logged by: Plate: � 99037 Feoruarv 1999 SES 9 J-7452 12/00 Figure C-2 3/3 � �< 5 00` t3VK1(VV J �� r � � F `e � , `'�QE`'`� �,�o-�°�� 4�( �a�� JS�'� Description Gravel over FILL Light brown, silty SAND with some gravel, fine- to medium-graine�, ver� moist, laose (FILL) 5 Push 1 � I � I i I ! ' Light gray, si;ty SAND, fine-grained, wet, very loose - S M; � — � i Light gray SAND, medium to coarse-grained, wet, loose 10 8 2 � 15 6 3a SP 20 11 4 � 25 � 5 � 30 4 6 � - becomes fine- to medium-grained � ; ' ! I 35 1 i � ; ; I ; i � ' L;ght grayish-brown, slightly sandy SILT, low plasticity, wet, very loose iI � I � ML i I � J I - becomes sandier 40 II I � � BORING 3 !S COlYTlNUED ON NEXT' PAGE, PLATE 1 f BORIti G LOG ___ � G�O TE C H 1101 Lake Washington Boulevard Nor�n C()NSUL7'AN'I'S, INC. � Renfon, Washington � _ _ __ Job: Date: Logged by: Plate: 99G37 Fe�rua�v 1999 SES 10 � J-7452 12/00 Figure C-3 1;4 � • � � 0' LJV� \11\V e/ �+V� �►�� v�,,v �� 9,� �o-`��e �o`� �,�� Q�" � . �Q�� ',�o-'°� � Q c�o.� JSG� Description 2 8 � :; ;�i� (continued from previous page) ; ; , �I � ML i 45 I �� !�I � 11 9 � , � snn � Light gray SAND, fine- to medium-grained, we;, medium-dens2 ; ; ++ j Light gray, sandy SILT interbedded with layers o` sand, low p(asticity, � wet, very loose �� ; 50 2 �0! , � I � ! I � Light gray, gravelly SAND, medium- to coarse grained, wet, med�um- 55 dense to dense 48 11 � 60 34 12� SP cc Zg 13� 70 27 14� 75 23 �� ' ' � ' ! ' ; Light gray, siity SAND, fine- to medium-grained, wet, medium-dense SM � ' � , � , � ij , , ML '� i Light greenish-gray, slightly sandy SILT, low plasticity, we!, loose 8� "'_'_'_' "'_'_'•'_'_'.'_._._._._._._..._._..._._._._._..._._._._._._._..._..._._._._._._._._._._..._._._._ BORING 3 IS CONTINUED ON NEXT PAGE, PLATE 12 BORI�G LOG � � G E O T E C H 1101 Lake Washington Boulevard North CUN�UI:r,�rrr•s, rryc. � Renton, Washington � Job: Date: Logged by: Plate: � 99037 r'ebruarv 1999 SES >> J-7452 12/00 FTgure C-3 2�4 ' Q� 4 O�, � � ' ''' ' � � � � ' '�.. . r.� �.. �i� ..�� b� �e �o`� �t� F�� GS �� ,�o-�° 6 Q r�o-`� �S Description M=do.2% 4 'o� � 1 ( � � � (continued from previous page} ML � � III $� II I � 68 17� gM Light gray, silty SAND, fine- to medium-grained, wet, very dense ; '� t � � � Light gray, slightly gravelly SAND, medium- to coarse grained, wet, ver; dense 90 � SO/5" �g' SP - less gravel 95 73 19� ' � � i I ' i �ight gray SAND, fine- to medium-grained, wet, very dense ! I � � � If I : 100 26 2�� SM - becomes siity and medium-dense I � � li �Ili ( , I i � ( 105 R , , il , 2� 2� � i i ' � Light gray, cfayey SILT, medium-plasticity, wet, stiff ; � ; � � � � � i � ' li , , l , 110 2 2Z� ' � ' � � - becomes soft � " jl , i � � ML i � i 115 ' ll ) M=ao.2% 3 23� � ' I ! � � � ' ) i 120 !_.!;�._. ._--•-•-•-•-•---•-•-•-•-•-•-•-•-•-•-.-•-•---•-._._._._._._._..._._._._._._._._._._._._._._._._._.. BORING 3 /S CONT/NUED ON IYEXT PAGE, PLATE 13 BORING LOG � � G �OT�C H 1101 Lake Washington Boufevard Na�th C()'�SL!LTAh'TS, [tiC. � Renton, Washington � � - Job: Date: Logged by; Plate: � �_.—�—- ---- 99G3' Februarv 1999 SES � J-7452 12/00 Figure C-3 3/4 � • � � oo� �V(ZIIVV J l.Vllll( IUCU ,�, C, �2 `J �F `� , . �QeS`� `�,�o-�0��`� QQ �o-fi� �SG� Description 1 24 � � (continued from previous page) I , , ,; I I �, ' ! ii � 'f 25 � 6 258 I � - becomes medium-sti�f � I � ML � � Ill . l � � , 130 2 26� I � � � � - becomes soft I i ' � � , I � 135 40 27 � Light gray SANG, fine- to medium-grained, wet, dense 140 52 28� SP - becomes coarser, very dense - �- 57 29� ' Test boring was terminated at 146.5 feet during drilling on February 24 8� 25, 1999. ' Groundwater seepage was encountered at 7 feet during drilling. �� 150 II 155 160 BORI�'�G LOG �_ � G�O T E C H 1101 Lake Washington Boulevard Nor�h C(�NSUL'i'Ati 1'S, INC. � Renton, Washington � � _ Job: Date: Logged by: Plate: 99037 Februarv 1999 SES �� J-7452 12/00 Figure C-3 4/4 � � o� BORING 4 �`� �o,� o-`�`e �o`� ��F� Q`� 5 I' - . �� ,�o-�° 0 Q Sa� JSG Description Gravel over FfLL Light brown, silty SAND with gravel, extensive organics, fine-graine�, Ivery moist, loose (FILL) � Light gray SAND, medium- to coarse grained, wet, loose � 5 1 � ( I 10 � 2 ` ( I �5 g 3 � - with some gravel I 2p 8 4 � - becomes gravelly ` SP I 2' 14 5 � - beccmes medium-dense ( I 30 10 6 � - beco-nes fine- to medi�m-g;ained ( 35 13 7 � - with trace of siit ( ' � � Ligh; brown, sandy SI�T interbedded with sand lay�rs, (c�v ��asti�ity, M� j wet, very loase I qp �---•--- -•-•-•-•-•-�-•---•-•-�---•-•-•-•-�-•-•-•-•-•-•-•-•-•-•---•-•---•-•-•-•-�-•-•-•-•-•-•-�-•-•---•-�- - BORlNG 4 IS COIYTINUED ON lYEXT PAGE, PLATE 15 I - '� BORING LOG ( � � G E O T E C H 1101 Lake Washington Boulevard North Cc)N�l;L'i'.avl'S. INC. � Renton, Washington I �Q � Job: Oate: Logged by: Plate: '�� 9903' Februar: �949 SE� '4 J-7452 12/00 Figure C-4 1!3 �,< 5 0� ... ... ... . v . v... .�.. .v.v..+ �e`` �Qr bt �� `�� Q`� � `'�e7 � �,�o-�° � Q So-fi �C� Description_ M=51.7% 2 8 ;;� I � (continued from previous page} , Ii i 45 g 9 M� � - becomes lignt gray � � � �i i , � �I � �i � � �:; 50 Light gray, gravelly SAND, medium- to coarse grained, wet, medium- M=22.�/ 27 �� dense 5, 38 � � � - becomes dense 60 2z �2� - becomes fine- to medium-grained, medium-dense �� 13 13 � - becomes gravaliy 7Q SP 6 �q O - becomes med:um- to coarse grained, loose 75 28 �� - becomes medium-dense 80 M� _ .Greenish.gray, sandy_SILT,_low piast�city, wet, very_loose_ _ _ _ _ _ _ _ _ _ . BORING 4 fS CONTlNUED OIY NEXT PAGE, PLATE 16 BORING LOG � G �O TE C H 1101 Lake Washington Boulevard North � CUNSULTAN'TS, irvc. Renton, Washington � � Job: Dare: Logged by: Plate: r�— 99037 February 1999 SES 15 J-7452 12/00 F�gure C-4 2/3 • � Op- ✓v� �� •v � vv� �� a.r�.�.. F�� ``e`�- �.�� 4 Q�� 5 �� ,�o-�° � Q 50�` �5G Descnpiior� , M=53.1:e 3 16� i � ' ' (continued from previous page) � , , � ML � • : � I 8� � I 30 17 IiII1 1 � ; gM � Gray, silty SAND, fine- to medium-grained, wet, dense � � Gray, graveily SAND, fine- to coarse-grained, wet, very dense 90 50/5" �g' SP 9' S3 19� ` Test boring was terminated at 96.5 feet during drilling on February 18, 1999. ' Groundwater seepage was encountered at 4.5 feet during driliing. 100 105 110 115 ( 120 � � BORI:VG LOG � � G�O T E C H 11 C 1 Lake Washington Boulevard North I Cf)NSULTAN"I'S, INC. � Renton, Washingfon �� Job: Date: Logged by: Plate: I �� 99C37 Fe�ruarv 1999 SES 16 , J-7452 12/00 Figure C-4 3/3 � �� tiUKINV 5 �� ..A� o-`��.e �� Q�� 5 �Q¢� �,�o-�° � � 50-� �SG Description FILL Gravel over Ligh! brcwn, sandy SILT with some organics, low plasticity, maist, ver� loose (FILLj ' ' �I�I Light gray, silty SAND, fine- to medium-grained, moist, very loose , �� 5 � � � I ; SM i � ;� I �II �o '� � i� 7 2 � Light gray SAND, fine- to medium-grained, wet, loose 15 �g 3 � - with trace gravel, medium-dense SP 20 18 4 � II !� � � ! �; Light gray, sandy SILT, low plasticity, wet, very loose I I , : � � ; 2 5 � ' ` ' i � ��,l � ML � �'! i 30 2 6 '; ' j;, =d1.4% � I i � � � i�� j ; ; i � 35 � 17 7 � Dark gray SAND, fine- to medium-grained, wet, medium-dense SP 40 --.---•- -•-•-•---•-•-.-.-.---•-•---.-._..._._..._._._._..._._..._._._._._._._._._._._._._._._._._._._._._.. BORING 5 IS CONTINUED ON NEXT PAGE, PLATE 18 _. BORIi�G LOG . , GE01 �CH h � 1101 Lake Washington Boulevard Nort }� CnN�t,'L'1'AN"t:S, INC. � Renton, Washington �, � Job- Dafe: Logged by: Plate: �� 99o37 Februarv 1999 SES �� J-7452 12/00 Figure C-5 1;`2 - � � � ,�o• C3VK1(VV � LUIIlI11U�U °`�'.�r db`� \��Q2�C Q i � �Q � �,�'° � �,d�` JS�' Description 9 8 � - with trace gravel, ioose 45 �6 9 � SP - becomes medium-grained, medium-dense 50 3 10 ' �� i I Dark gray SILT, low plasticity, wet, very loose � � i � , �I i� + �� 5 3 11 � M� ' - becomes olivelgreenish-gray ,I� �I � ,�� so ; � 2 �2 � �� ;,i � , i �� - becomes sandy � II � .._�.._._�. � rk gray, gravelly, sifty SAND, medium- to coarse grained, we±, 65 M_'2 9/ 28 13 � �i �' � medium-dense , ;�ili; �ilt�!i� �� `! � 70 40 14 � SM ' _ becomes dense to very dense � .� i�i ji � ;��'i � 75 53 15 � ;'I;''!� � ' Test boring was terminated at 76.5 feet during driliing on February 18 8� 19, 1999. 80 BORI'�'G LOG � � G �O T E C H 1101 Lake Washington Boulevard No�'h CUNSUL'I'Ar!"I�S, INC. � Renton, Washington �� _ Job: Date: Logged by: Plate: 99037 February 1999 ScS �� J-7452 12/00 ' Figure C-5 2/2 — C PT-1 � ( ��'� -- _ -- ------------_----------.- _ _ _- -- - - _._—_-- Cone Penelr+llon Reslst�nce i (lonhq.ft) Frlctlon Ratlo(Y.� S o l l In t e r pr�t�l lo n � 0 t� 200 300 400 � 0 5 10 t5 � p I r----i 0 ( �r�velly FIII Z � � i � , I �SAND, looee V' — ---- '1 � � _. ._ t0 �becom�• �Ilty ,..J O 10 — -- � r� :i � becomes medlum-denee � ; � 1 I > ►� I � , I � 20 - — ---- -- — i� — - -- p I Sllty SAND, medlum-den�e ;,; h ; ;i I-i - -__ ... n I ; I � L � — — . � S�1ND, medlum-denee �; — �� — -�-- --� - -- 30 I 30 -�-- 11 � � � I ; �' I --► - � , oep�n 'b _ ---- --- - - --- �� i . --�—r-- - - 4o I _ L � Below �` i I LyJS�ndy 91LT, •111f �� Ground �� I � �� c� z Q O Surlace(tt) :� � OQ � SO — _ �--- — ! ----- —._ . . f�0 w ' - --- - -� � i. ; . � � � 7 � ;i ; i i �� r ( i �' � � D �� b � � � � � • -- ' I -' ' � SAND, den�e lo vary den�e -.. � � C~ i I I -�I--- -- �� 7 � � � O � � � I I � I 911ty 9ANU, medlum-den�e � � � 70 �t 70 , II � beComes le�e •Ilty � `� o I �' � ( I cv o ' ' _ �, � f gp - � , E10 i Sandy 91LT, ��rd 'r C:^ c. �� o C'7 I � ► ,, , � � , i � C , SAND, very den�• C � o � � � I I . _ . . I . ._ . I ..I._ . _ _ _. . � ; � N � � � ' ,I I (') � N - - - ; __ - -. ' --------_ __-- - --- - -- � �, Q _ _ - - a� '° "'� Z �-; o � r, � � —� N O O , C PT-2 � ( ��_ �-� , -- - — - -- - _ __ _ _- � - ------ - —-- _-- � Cone Penelratlon Real�t�nte � — - � Frlcllon Ra110 ' ( (toN�q.H� I I/�) I Soll Inlerpretatlon � 0 10p 200 300 4pp t 0 5 10 15 I � ; � n ^ � � �— � 0 I ' Or�velly FIII � `^, �� ! i � ; Cleyey SILT, very eolt � � h ! , . , . r:. I � I SANO, loo�• rO . , , , � �p `� .. __ _ _ _ _. � � � !Sllty SANO, medlum-danse � � ! � ! . I ' I � ' ' ' �-, � j � �) , � Ciayey SIIT, hercl � �/�) � , , =qp 'I_." ' .I- -. ._____( I� • _ ;�' 1 ` ' � I � � iI I - - � � � ��AFIQ, danea to very dense _ :-� x � � _ � ') i I � Grevelly S/1ND, denee i � ' : il i I ' � � , � - - - 1 ,- �_.-- � � I f i I S�fJD, medlum-�eneo to donee I � Deplh 'I ' ' + L. I _ " _ I -: -- - I I I , I O --� ^ Below I �p � —a ` ' Ground.__� , I __--• ._..___� _ . ._._. � op � O I Surtace�ft� I I i i I ' ly Isyuy SIIT, herd i r � � , i "' � � � ' � ' � ; ISllty SAND, madlum-denee to denea 7�- � Ifl0 --- � _ __ . __._._ I I I I � g O � CD � � I -` _-- -- . ..._ f 00 � --._ . -- ' becomee less ellty !� � G r I � i ( I I ! �Sandy SILT, herd � �� . � � � : i , o �. .-� �_o - - - - �- ' � ,�o ; � , _ — ►..� I I I ' , !bacomee vory hard � � I II C � ~ I � O O I � � , Sllly SANO, medium-danae �. � f f 140 � ' � . . 1 m � � ` �' O y� i I , i SAND, madlum-den�e �C1 V � � l 1 i i o — ' i � N � � � h �ao ._ .. . . .. . .. � ,eo � � . . . v � c�. N _ I � y - __ _ __ � - _ __ _ _. .__ _ . _ _- o r _. � o � H N O O -- — — — — — — — — — -- — — ---�- -- — . C PT-3 � � � � �� ``'� _ _ -- --- ------ - ----- - - -------- --� - - — - Cone Penelratlon Reslslance � � (�o��:q.n� FrlcUon Ratlo(Y.� 9011 Inlerpr�l�tlon i , o �o0 200 30o noo 0 5 to � ('; 0 0 pravelly FI11 � i � I � —"'� SanCy SILT� very �all Z M•� I ' I !.� �yJ � I � � O 10 - -- --- •----'----� i L --- SAND, medlum-den�• � i i � {--- ,o � � I I � I) i I Sllty SAND, medlum-denee � h � _ I � --l---_._� �� I ;__._---- p r � � _ �._. _ .-�---- i I i 7 � ( become• looee n I ' �) --1 ; _� � � � � � S�ndy SILT, medlum-�Ilff I � I I i I I I SAND, deneo to very denee � , ` I qp . ___.. f. �... > >.--i , I--- 40 �. _._. p � Deplh I I ----- I tr � � I Below UZ Q O i Ground ! i I � ihecomee mndlurn-danea w � � � I Surf�ce(n) 50 - - ' I -- - - _ - 50 �• r � I , a� C'7 � I I ; I � g � � j : � , � o � �� C"� I so - .. .._ � . . ( _ . . . . . - eo � ' � � ' o c� h � I � � � � � � � � � 70 ---- — - - --�---- --- �o � i i -- —._._ _--- -- � O ✓ Sendy 91LT, herd � � O I ? SAND, very densu _' � r-r BO --- - -- _ ._. _. . .— _- --- -- - 90 �t c� � O �7 ' I � � �. C � I � � � � h � �o � N � � � � I Co � Q- ,.� _ . . _. O � -- -- -- .. . _ _ _ - N � � v � � ►�w N � O O � C PT-4 � � ( �� --------- _ ____-- -- _-- --. - -- _----- ---- ----- ---_ -__. --- � i ---- ------- - � Cone Penelrallon Resist�nce Soil Interpret�tlon �toNsq.t1) � FrIcllon Ratio(7.) 0 t00 :0p 3pp 4pp I 0 2 4 6 I � —�—� � � drevell FI11 C ^ I �'� i i9Uly 9AN0, loo�� ' I 9AND, medlum-dsn�e lo den�e Z ( s C� I � I , � ; � Sandy S�LT, madlum-�Ilfl lo stlll .-� O YJ -- -I_-- ----._��_ ! � � i � �� "- `� I I9AN0, loose lo m�d�um-dsn�e � I I i � � � I I . !' I � :I � �' r�.r �, � , C, 1� � - _i. --��--•- �i -- � � - 1 � . II i � — ---- � Cleyey 511T, e1f11 ----- I � �� I ' I ' ISendy SILT, etlt( � „ � �� I I � � oep�n ' ( 1' � Below � � � I ! become� leee nllty � ep �.�_�_ ;..---- � � Ground - -•I --•- — ( t--- --- .. . �_ - -- .. __ � I � z O Surfacc�ft) , � ' � � ' becomea herd o � � � I I w. 1 � I � ' V � �i I I I , � gp f,.._�.- ----I—_ -. ._. ' � g b � � -� ; , I- - I � � �� p < h � ! I � SAND, medlum-denee to denee � pCj �; I , � � j l � O (/� C='� � � andy 91LT, nard � � � � � i �� f00 - -. _ _.-.--- - . i i .I �� '!SAND, very den�e .-.' � � O O I I N = � ? ►"� I ?� � � O C� , : - � v ,.... c < _ . i . . i � � O � 120 -- � --_.__ _......_--- -- � t:� � � , � ' n � (� r, - __ _ _ _ _ _ _ , - - - _ .__ � �_. ____ __ --- ______ _ __--- - - _ co � a � . � � N � � � � 0 0 C PT-5 ' � � - � , � - _ ✓��'� - ----- -- -- --- __- - - - . � - --- --------- ---- --- -- �..� Cone Penelr�tlon Reslsl�nce I, (lonlsq.N) � Frltllon R�IIo(7,) 9011 Inl�rp��lallon 0 1Q0 :00 J00 <00 0 5 f0 i 0 I i 0 ("� n II � Cl�y�y , v�ty �o � � j ( ' Z � ! SI1H0, loo�� 10 — --- ---- ---� I I � - ------- 10 � O I � I I = � ! '� ' > ; � C� — _._.- �' ' -- --- --- - ' -I f ► � � -- -- i �. - � - :o � � t ' �� 'Ib�come� madlum-d�n�• to d�n�e ? ►*y � I � �beComs� pr�velly, loo�e • F��.� I � '' , � I 30 ---I ---�---} — I I -- - --- I I! � . I I' � 'Sandy SILT, msdlum-�tlfl �-�+ �I I Deplh I I Below � � , I� I ' SAND, dense lo very den�e p � ^ Ground `70 ---- -i— -----�--- ` i_ - .--- 40 �Q� � l J I Surlace(ft) I Wo o C , � � � j : I ; r � n� C" so —--- -�.___ I- ----�--- ------ so Dp � � I � � � . , ; aa � � � , � _.. � r-. , ; , � � � � I `�' �. � 1 � i ' i _ . _ � I O � n , �� ; ; il � o O �o - I �o N � � I �- � �., . � ` � o r-,; . .... � _� � I c � `� � — �o . . _. . . . . _ ... � `�° N b j � � _ i or,��o a ....� - . --------- ------- z �-; N O �j NW � '"'� � 0 0 I , , CPT-6 • � . ( . ,��'_ - �,`''�j�,_,, _ ------ . ---- ------- -.� . _ __ ....---- - ---- _ .i+� � Cone Pc�Nr�llo�Reslst�nce � �toNsq.tt� �� Frlcllon Rauo(%� I ' 9011 Inlerprel�tlon s ; � 0 �00 20D 3C0 a00 I 0 5 f0 IS (; ^ 0 I � `,� 1 � i j ; I 0 I ICir�velly FIII � � �� ; ` � Clayey gllT, •olf f I �. •I � � ~ O I �p _ .. __ ! __— - ---- j I j - -I-,..---I— �- 10 I � M� i ' i ;f I i SANO, medlum-den�a ( i 3h^ � �� ' � � i Z ` 1 I 2� - --�--��)---I-- '� i-- ---{ --- ---- � becoma� Ioo�e '� � I ' � �. I I I � I I �ndy SILT, m�dlum-�Illf lo sllll , i I � i �y � ;� � � � � ;� � , � i � ,i � �; I I �j � � � - � 4 � /� o�Pcn ( ,� � � rp 4 —a l l eelaw ' ' ...... . .. � ._. . 0 2 O (� Ground ' �,. + - _ . _ I _. . ;I i -- .--lu-_--„-i,.--•-- .--.- � ' i SANP. medlum-denea lo den�a �o —` 1 sur�ace(n) � , � i ; v i� I j � �I � � � � become• �Ilty �O � � .� i � ----�_ ____ ____ _. l i � . ___ _; _. _- 4 , so _� � � � �,�- � `� i I � I N = � ; �� i O cn m I !; j I I � �' , _ � � � - - , - - � -- - • i I I . i � 6p Decame• dan�e lo very d�n�o I ! , ' Cleyey SILT, hsrd iu Q Q � I �I j : �1 L ? � 1' :�� _ �� i I I SAND, medlum-den�e lo denss C A = O C�"�y'1 i - -- • �� I i _( _ . � f�D N � C � I ' �� II bacomes very densa C� N � fU � !j � � � �, � I � . I : I I � . � a � - .._ . __.-------�---- --- �I � "'� _ -----�- -._---_--_!. ____.--___ ._____.___ � z r N A � U o � � CPT-7 � � Z ( - � � N � � �� o - - - ----__- ------ --- _ _, _ .__ ( - -- - --__---------- n � �'� Cone Vcnelrallon Reslslance � � (tonlsq.f1) Fricllon R�tlo(Y.) 9011 Int�rpr�l�llon � � � � 0 100 :00 300 a0� 0 2 4 6 9 rn vi 0 � f � 0 � � ^ � ; i SAND, m�dlum-den�e � '� V � � �Cl�yey 91LT, •ofl � n Z M � � I --_ i � SANO, loo�a to m�dlum-den�e ;/; l'� O� a �. I 10 —� ! � - --�-- 10 - i � a y O I ; i I S�ndy S11.7, •oll lo madlum-�tlff � � � J I ( x O � I I � SAND, loo�e ° w ✓� � :° . ... . � � , I ro I � � � I . I ' ' i I p� � ('Z',� x ` � I I becomee medlum-dnnee to denee a N. I I + � � y --I -- --- �-- - -- •I--- 30 v� w 30 --- I ; — � I � � I � � I i � a I ! � i i I, ' �� D e p l h ; I ' j I � I � � � Below � — -- ---- I._ ._. _ ..,_ ' _ . . _ a0 � � — ///...�� Ground � ( : � I S�Ity SANO, medlum-de�ee _a f ' � --_ _ -- — �� O� � ^ Surl�ce�N) I , i Sendy SILT, •1111 a �O � v I i � , I i. ; � r �� I . , ; , : --- --- � h ' � I-- —' ---'- ---- � , � � �" i � � I � ' SAND, medlum-denes to densu �o � � "'� � I � � I, _ o, � � � ` _� � �� p� 7 I � ! � ( � 60 -- �. .__ . � . _ . _. gp O �, � I_ I � _ I _ i �' � � I I �� F•�y i N O Q �p � I _ I N � � � I ' � I �� Decome� very den�e C d O CrJ I I � � N O � � eo I .. . .._ _. I_. _. .... ! 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I � --- � � ,_,,7 ' SAND, mndlum-denen to donea � �' � �0 � -�--- -- I i— -._-- ----- ;I 70 (O ' � p Q I � I � ` � � � � Cleyey SILT, sllfl — � � � O � � ' - -- - � ' S�1ND, very denee - - (�D N � � y I c� � � C'7 � � _. v � -- ........ .. __. .------. _ .._.._.: i I... . _ ....... .. _ .. � � - - - w � a � -------- - Z - ------ y � o � - _---- - N o � "'� 0 ,I COUGHLINPORTERLUNDEEN __ __ _ _ _ . _ _ Appendix C STORMWATER POLLUTION PREVENTION PLAN (SWPPP) 2a n I Stormwater Pollution Prevention Plan For ' Southport Hotel ' Prepared For Northwest Regional Office , 3190 - 160th Avenue SE ' Bellevue, WA 98008-5452 425-649-7000 Owner Developer Operator/Contractor SECO Development, Inc. SECO Development, Inc. TBD 1083 Lake Washington 1083 Lake Washington TBD Boulevard North, #50 Boulevard North, #50 ' Renton, Washington 98056 Renton, Washington 98056 TBD Project Site Location Renton, Washington Certified Erosion and Sediment Control Lead I TBD SWPPP Prepared By Coughlin Porter Lundeen I, 801 Second Ave Suite# 900 �� Seattle, WA 98104 �� (206) 343-0460 ��, Chase Blood, Civil Engineer SWPPP Preparation Date 12/19/2014 Approximate Project Construction Dates TBD �I n I Contents 1.0 Introduction...............................................................................................................................l 2.0 Site Description ........................................................................................................................3 2.1 Existing Conditions...........................................................................................................3 2.2 Proposed Construction Activities......................................................................................3 3.0 Construction Stormwater BMPs...............................................................................................5 3.1 The 12 BMP Elements.......................................................................................................5 3.1.1 Element#1 —Mark Clearing Limits...................................................................5 3.1.2 Element#2—Establish Construction Access.....................................................5 3.1.3 Element#3 —Control Flow Rates.......................................................................6 3.1.4 Element#4— Install Sediment Controls.............................................................6 3.1.5 Element#5 —Stabilize Soils...............................................................................7 3.1.6 Element#6—Protect Slopes...............................................................................8 3.1.7 Element#7—Protect Drain Inlets.......................................................................8 3.1.8 Element#8—Stabilize Channels and Outlets.....................................................9 3.1.9 Element#9 —Control Pollutants.........................................................................9 3.1.10 Element#10—Control Dewatering.................................................................1 l 3.1.11 Element#11 —Maintain BMPs.......................................................................11 3.1.12 Element#12—Manage the Project..................................................................1 l 5.0 Pollution Prevention Team ......................................................................................................21 5.1 Roles and Responsibilities...............................................................................................21 5.2 Team Members................................................................................................................21 6.0 Site Inspections and Monitoring.............................................................................................23 6.1 Site Inspection.................................................................................................................23 6.1.1 Site Inspection Frequency ................................................................................23 6.1.2 Site Inspection Documentation.........................................................................23 6.2 Stormwater Quality Monitoring......................................................................................24 6.2.2 pH Sampling.....................................................................................................24 7.0 Reporting and Recordkeeping ................................................................................................27 7.1 Recordkeeping.................................................................................................................27 7.1.1 Site Log Book...................................................................................................27 '� 7.1.2 Records Retention.............................................................................................27 7.1.3 Access to Plans and Records............................................................................27 7.1.4 Updating the SWPPP........................................................................................27 7.2 Reporting.........................................................................................................................28 7.2.1 Discharge Monitoring Reports.........................................................................28 7.2.2 Notification of Noncompliance........................................................................28 ' 7.2.3 Permit Application and Changes......................................................................28 � ii n AppendixA— Site Plans.........................................................................................................29 AppendixB —Construction BMPs.........................................................................................30 Appendix C —Alternative BMPs............................................................................................31 AppendixD—General Permit ................................................................................................33 Appendix E— Site Inspection Forms (and Site Log)..............................................................34 Appendix F—Engineering Calculations.................................................................................43 Appendix A Site plans Appendix B Construction BMPs Appendix C Alternative Construction BMP list Appendix D General Permit Appendix E Site Log and Inspection Forms Appendix F Engineering Calculations iii Stormwater Pollution Prevention Plan 1.0 Introduction This Stormwater Pollution Prevention Plan (SWPPP)has been prepared as part of the NPDES stormwater permit requirements for the Riverside Heights construction project in Renton, Washington. The site is situated at the southern tip of Lake Washington to the west of the Gene Coulon Memorial Beach Park. The site is in the NW '/4 of the NW '/4 of Section 8, Township 23 North, Range 5 East, Willamette Meridian. The site will occupy parcels 0823059216 and 0523059075, with areas of 187,460-SF and 296,821-SF, respectively. The existing site consists of 2.5 acres of impervious area and 5.49 acres of pervious area. Overall, the proposed project will include a 10-story hotel and general site improvements including landscaping, a parking area, and a fire lane. The proposed conditions will consist of approximately 7.09 acres of impervious area and 0.9 acres of pervious area. Construction activities will include demolition, excavation, grading, relocation of onsite services/utilities, construction of a high-rise hotel with associated surface parking and landscaping. The purpose of this SWPPP is to describe the proposed construction activities and all temporary and permanent erosion and sediment control (TESC) measures, pollution prevention measures, inspection/monitoring activities, and recordkeeping that will be implemented during the proposed construction project. The objectives of the SWPPP are to: 1. Implement Best Management Practices (BMPs) to prevent erosion and sedimentation, and to identify, reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. Prevent violations of surface water quality, ground water quality, or sediment management standards. 3. Prevent, during the construction phase, adverse water quality impacts including impacts on beneficial uses of the receiving water by controlling peak flow rates and volumes of stormwater runoff at the Permittee's outfalls and downstream of the outfalls. This SWPPP «�as prepared using the Ecology SWPPP Template downloaded from the Ecology website on December 17, 2014. This SWPPP was prepared based on the requirements set forth in the Construction Stormwater General Permit, Stormwater Management Manual for Wester•» Washington (SWMMWW 2005) and in the Stormwater Management Manual for Eastern Washington (SWMMEW 2004). The report is divided into seven main sections with several appendices that include stormwater related reference materials. The topics presented in the each of the main sections are: • Section 1 —INTRODUCTION. This section provides a summary� description of the project, and the organization of the SWPPP document. l Stormwater Pollution Prevention Plan ■ Section 2 — SITE DESCRIPTION. This section provides a detailed description of the existing site conditions, proposed construction activities, and calculated stormwater flow rates for existing conditions and post— construction conditions. ■ Section 3 —CONSTRUCTION BMPs. This section provides a detailed description of the BMPs to be implemented based on the 12 required elements of the SWPPP (SWMMEW 2004). ■ Section 4—CONSTRUCTION PHASING AND BMP IMPLEMENTATION. This section provides a description �f the timing of the BMP implementation in relation to the project schedule. ■ Section 5 —POLLUTION PREVENTION TEAM. This section identifies the appropriate contact names (emergency and non-emergency), monitoring personnel, and the onsite temporary erosion and sedimentation control inspector ■ Section 6—INSPECTION AND MONITORING. This section provides a description of the inspection and monitoring requirements such as the parameters of concern to be monitored, sample locations, sample frequencies, and sampling methods for all stormwater discharge locations from the site. ■ Section 7—RECORDKEEPING. This section describes the requirements for documentation of the BMP implementation, site inspections, monitoring results, and changes to the implementation of certain BMPs due to site factors experienced during construction. Supporting documentation and standard forms are provided in the following Appendices: Appendix A—Site plans Appendix B —Construction BMPs Appendix C —Alternative Construction BMP list Appendix D—General Permit Appendix E— Site Log and Inspection Forms Appendix F —Engineering Calculations , Stormwafer Pollution Prevention Plan 2.0 Site Description 2.1 Existing Conditions The existing site consists of asphalt and gravel parking lots as well as open grassy areas. The site was previously home to the Shuffleton Steam Plant, which was built in the 1930's and demolished in 2001. Portions of the steam plant infrastructure are still in place, including a large underground concrete vault, which this project proposes to reuse to provide water quality treatment for runoff from the surface parking lot. The site is situated at the southern tip of Lake Washington to the west of the Gene Coulon I, Memorial Beach Park. The site is in the NW '/4 of the NW '/4 of Section 8, Township 23 North, ', Range 5 East, Willamette Meridian. The site will occupy parcels 0823059216 and 0523059075, ', with areas of 187,460-SF and 296,821-SF,respectively.. The site is 7.99 acres in size and includes a landscaped area with associated parking. The topography of the site and surrounding properties gently slopes to the northwest. Per the geotechnical report, soil depth and thickness varies greatly throughout the site. Generally, the site is silty sand and clay over silt. Groundwater lies approximately three to nine feet below existing grade, varying on the elevation of the adjacent Lake Washington. , Runoff from the site generally infiltrates or sheet flows into the existing catch basins which ', divert runoff to the existing storm network, ultimately discharging directly to Lake Washington. There are no critical areas on the site such as high erosion risk areas, wetlands, streams, or steep slopes (potential landslide area). 2.2 Proposed Construction Activities II Overall, the project will include a 10-story hotel and general site improvements including II�', landscaping, a parking area, and a fire lane. The existing site consists of 2.5 acres of impervious ', area and 5.49 acres of pervious area. The proposed conditions will consist of approximately 7.09 ' acres of impervious area and 0.9 acres of pervious area. Two existing wetvaults will be used to , treat PGIS from two basins, while two StormFilter cartridge vaults will treat runoff from the � remaining PGIS. New sanitary, electrical, gas, and storm drain utilities will also be constructed. , Construction activities will include site preparation, TESC installation, demolition of the existing warehouse structure, excavation for the building foundations, poured concrete foundations, concrete construction, site-wide grading, and asphalt paving. The schedule and phasing of BMPs during construction is provided in Section 4.0. Stormwater runoff volumes were calculated using the computer software KCRTS. The �'I temporary sedimentation pond that will be used during construction was designed using the 2- 'I 3 I� Stormwater Pollution Prevenfion Plan year storm event. These are peak flows based on the developed conditions throughout construction. The ponds were all is sized using BMP 251 and are intended for stormwater treatment of total suspended solids and stormwater detention. Calculations for all ponds in phase I and a sample calculation on how the ponds were sized are all included in Appendix F. The following summarizes details regarding site areas: ■ Total site area: 7.99 acres ■ Percent impervious area before construction: 31 % ■ Percent impervious area after construction: 89 % ■ Disturbed area during construction: 7.99 acres ■ Disturbed area that is characterized as impervious (i.e., access roads, staging, parking): 7.99 acres All stormwater flow calculations are provided in Appendix F. 4 Stormwater Pollution Prevention Plan I 3.0 Construction Stormwater BMPs '� 3.1 The 12 BMP Elements 3.L1 Element#1 —Mark Clearing Limits �� To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of construction will be clearly marked before land-disturbing activities begin. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated, both in the field and on the plans. In general, natural vegetation and native topsoil shall be retained in an undisturbed state to the maYimum extent possible. The BMPs relevant to marking the clearing limits that will be applied for this project include: � High Visibility Plastic or Metal Fence (BMP C 103) Alternate BMPs for marking clearing limits are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.2 Element#2—Establish Construction Access Construction access or activities occuning on unpaved areas shall be minimized, yet where I necessary, access points shall be stabilized to minimize the tracking of sediment onto public roads, and wheel washing, street sweeping, and street cleaning shall be employed to prevent sediment from entering state waters. All wash wastewater shall be controlled on site. The specific BMPs related to establishing construction access that will be used on this project include: � � Stabilized Construction Entrance (BMP C105) • Wheel Wash(BMP C 106) � Construction Road/Parking Area Stabilization (BMP C 107) I Alternate construction access BMPs are included in Appendix C as a quick reference tool for the �! onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the I NPDES Construction Stormwater permit(as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the I 5 Stormwaier Pollufion Prevention Plan alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.3 Element #3 —Control Flow Rates In order to protect the properties and waterways downstream of the project site, stormwater discharges from the site will be controlled. The specific BMPs for flow control that shall be used on this project include: No BMPs to be implemented Alternate flow control BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, the project must comply with Minimum Requirement 7 (Ecology 2005). , In general, discharge rates of stormwater from the site will be controlled where increases in impervious area or soil compaction during construction could lead to downstream erosion, or where necessary to meet local agency stormwater discharge requirements (e.g. discharge to combined sewer systems). 3.1.4 Element #4—Install Sediment Controls All stormwater runoff from disturbed areas shall pass through an appropriate sediment removal BMP before leaving the constntction site or prior to being discharged to an infiltration facility. The specific BMPs to be used for controlling sediment on this project include: • Detention Pond Or Vault � Storm Drain Inlet Protection (BMP C220) Alternate sediment control BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix ' D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the 6 Stormwater Pollufion Prevention Plan alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. In addition, sediment will be removed from paved areas in and adjacent to construction work areas manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from the site and to minimize washoff of sediments from adjacent streets in runoff. Whenever possible, sediment laden water shall be discharged into onsite, relatively level, vegetated areas (BMP C240 paragraph 5, page 4-102). In some cases, sediment discharge in concentrated runoff can be controlled using permanent stormwater BMPs (e.g., infiltration swales, ponds, trenches). Sediment loads can limit the effectiveness of some permanent stormwater BMPs, such as those used for infiltration or biofiltration; however, those BMPs designed to remove solids by settling(wet ponds ar detention ponds) can be used during the construction phase. When permanent stormwater BMPs will be used to control sediment discharge during construction, the structure will be protected from ' excessive sedimentation with adequate erosion and sediment control BMPs. Any accumulated sediment shall be removed after construction is complete and the permanent stormwater BMP will be restabilized with vegetation per applicable design requirements once the remainder of the The following BMPs will be implemented as end-of-pipe sediment controls as required to meet permitted turbidity limits in the site discharge(s). Prior to the implementation of these technologies, sediment sources and erosion control and soil stabilization BMP efforts will be maximized to reduce the need for end-of-pipe sedimentation controls. ■ Tem ora Sediment Pond BMP C241 � P rY � ) ■ Construction Stormwater Filtration (BMP C251) ■ Construction Stormwater Chemical Treatment (BMP C 250) (implemented only with prior written approval from Ecology). I� 3.1.5 Element #5— Stabilize Soils � Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent erosion throughout the life of the project. The specific BMPs for soil stabilization that shall be used on this project include: • Temporary and Permanent Seeding (BMP C 120) Alternate soil stabilization BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate 7 Stormwater Po!lutron Prevention Plan during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, no soils shall remain exposed and unworked for more than 7 days during the dry season (May 1 to September 30) and 2 days during the wet season (October 1 to April 30). Regardless of the time of year, all soils shall be stabilized at the end of the shift before a holiday or weekend if needed based on weather forecasts. In general, cut and fill slopes will be stabilized as soon as possible and soil stockpiles will be temporarily covered with plastic sheeting. All stockpiled soils shall be stabilized from erosion, protected with sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels. 3.1.6 Element#6— Protect Slopes All cut and fill slopes will be designed, constructed, and protected in a manner than minimizes erosion. The following specific BMPs will be used to protect slopes for this project: • Temporary and Permanent Seeding(BMP C 120) Alternate slope protection BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.7 Element#7—Protect Drain Inlets All storm drain inlets and culverts made operable during construction shall be protected to prevent unfiltered or untreated water from entering the drainage conveyance system. However, the first priority is to keep all access roads clean of sediment and keep street wash water separate from entering storm drains until treatment can be provided. Storm Drain Inlet Protection (BMP C220) will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment-laden runoff on and near the project site. The following inlet protection measures will be applied on this project: 8 i Stormwater Po!lution Preventron Plan Drop Inlet Protection �I • Catch Basin Filters If the BMP options listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit(Appendix D), or if no BMPs are listed above but deemed necessary during construction, the Certified Erosion and Sediment Control Lead shall implement one or more of the alternative BMP inlet protection options listed in Appendix C. , 3.1.8 Element#8— Stabilize Channels and Outlets Where site runoff is to be conveyed in channels, or discharged to a stream or some other natural drainage point, efforts will be taken to prevent downstream erosion. The specific BMPs for channel and outlet stabilization that shall be used on this project include: No BMPs to be implemented , Alternate channel and outlet stabilization BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, all temporary on-site conveyance channels shall be designed, constructed, and stabilized to prevent erosion from the expected peak 10 minute velocity of flow from a Type 1 A, 10-year, 24-hour recurrence interval storm for the developed condition. Alternatively, the 10-year, 1-hour peak flow rate indicated by an approved continuous runoff simulation model, increased by a factor of 1.6, shall be used. Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent streambanks, slopes, and downstream reaches shall be provided at the outlets of all conveyance systems. 3.1.9 Element#9—Control Pollutants All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well organized, and free of debris. If required, BMPs to be implemented to control specific sources of pollutants are discussed below. 9 Stormwater Pollution Prevention Plan � Vehicles, construction equipment, and/or petroleum product storage/dispensing: ■ All vehicles, equipment, and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills. ■ On-site fueling tanks and petroleum product storage containers shall include secondary containment. ■ Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. ■ ln order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. ■ Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Demolition: ■ Dust released from demolished sidewalks, buildings, or structures will be controlled using Dust Control measures (BMP C 140). ■ Storm drain inlets wlnerable to stormwater discharge carrying dust, soil, or debris will be protected using Storm Drain Inlet Protection (BMP C220 as described above for Element 7). ■ Process water and slurry resulting from sawcutting and surfacing �I, operations will be prevented from entering the waters of the State by implementing Sawcutting and Surfacing Pollution Prevention measures (BMP C 152). � Concrete and grout: ■ Process water and slurry resulting from concrete work will be prevented from entering the waters of the State by implementing Concrete Handling measures (BMP C 151). � Sanitary wastewater: ■ Portable sanitation facilities will be firmly secured, regularly maintained, and emptied when necessary. lo Stormwater Pollufion Prevention Plan ■ Wheel wash or tire bath wastewater shall be discharged to a separate on- site treatment system or to the sanitary sewer as part of��heel W'ash implementation (BMP C l 06). Solid Waste: ■ Solid ��aste �vill be stored in secure, clearly marked containers. The facility does not require a Spill Prevention, Control, and Countermeasure (SPCC) Plan under the Federal regulations of the Clean Water Act (CWA). 3.1.10 Element#10 —Control Dewatering There will be no dewatering as part of this construction project. 31.11 Element #11 —Maintain BMPs �� All temporary and permanent erosion and sediment control BMPs shall be maintained and �� repaired as needed to assure continued performance of their intended function. Maintenance and ', repair shall be conducted in accordance with each particular BMPs specifications (attached). i Visual monitoring of the BMPs will be conducted at least once every calendar week and within , 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes ' inactive, and is temporarily stabilized, the inspection frequency will be reduced to once every month. All temporary erosion and sediment control BMPs shall be removed within 30 days after the final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs or vegetation shall be permanently stabilized. 3.L12 Element#12 —Manage the Project �' Erosion and sediment control BMPs for this project have been designed based on the following principles: ■ Design the project to fit the existing topography, soils, and drainage patterns. ■ Emphasize erosion control rather than sediment control. '' ■ Minimize the extent and duration of the area exposed. ■ Keep runoff velocities low. ■ Retain sediment on site. ' 11 Stormwater Pollution Prevention Plan ■ Thoroughly monitor site and maintain all ESC measures. ■ Schedule major earthwork during the dry season. In addition, project management will incorporate the key components listed below: As this project site is located west of the Cascade Mountain Crest, the project will be managed according to the following key project components: ' Phasing of Construction ' The construction project is being phased to the extent practicable in order I to prevent soil erosion, and, to the maximum extent possible, the transport of sediment from the site during construction. ■ Revegetation of exposed areas and maintenance of that vegetation shall be an integral part of the clearing activities during each phasc of construction, per the Scheduling BMP (C 162). Seasonal ��Vork Limitations ■ From October 1 through April 30, clearing, grading, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt-laden runoff will be prevented from leaving the site through a combination of the following: ❑ Site conditions including existing vegetative coverage, slope, soil type, and proximity to receiving waters; and ❑ Limitations on activities and the extent of disturbed areas; and ❑ Proposed erosion and sediment control measures. ■ Based on the information provided and�'or local �;�eather conditions, the local permitting authority may e�pand or restrict the seasonal limitation on site disturbance. ■ The following acti��ities are exempt from the seasonal clearing and grading limitations: ❑ Routine maintenance and necessary repair of erosion and sediment control BMPs; 12 Stormwater Pollution Prevenfion Plan ❑ Routine maintenance of public facilities or existing utility structures that do not expose the soil or result in the removal of the vegetative cover to soil; and ❑ Activities where there is 100 percent infiltration of surface water runoff within the site in approved and installed erosion and ' sediment control facilities. �� Coordination with Utilities and Other Jurisdictions �i ■ Care has been taken to coordinate with utilities, other construction I projects, and the local jurisdiction in preparing this SWPPP and scheduling the construction work. Inspection and Monitoring ■ All BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function. Site inspections shall be conducted by a person who is knowledgeable in the principles and practices of erosion and sediment control. This person has the necessary skills to: ❑ Assess the site conditions and construction activities that could impact the quality of stormwater, and ❑ Assess the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. ■ A Certified Erosion and Sediment Control Lead shall be on-site or on-call at all times. , ■ Whenever inspection and/or monitaring reveals that the BMPs identified �!, in this SWPPP are inadequate, due to the actual discharge of or potential ' to discharge a significant amount of any pollutant, appropriate BMPs or I design changes shall be implemented as soon as possible. ; Maintaining an Updated Construction SWPPP ■ This SWPPP shall be retained on-site or v��ithin reasonable access to the site. ■ The SWPPP shall be modified whenever there is a change in the design, I construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the state. ]3 Stormwater Pollution Prevention Plan ■ The SWPPP shall be modified if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The SWPPP shall be modified as necessary to include additional or modified BMPs designed ro correct problems identified. Revisions to the SWPPP shall be completed within seven (7) days following the inspection. Alternate dewatering control BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit(Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit(as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.11 Element #11 — Maintain BMPs All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP's specifications. Visual monitoring of the BMPs will be conducted at least once every calendar week and within 24 hours ' of any rainfall event that causes a discharge from the site. lf the site becomes inactive, and is temporarily stabilized, the inspection frequency will be reduced to once every month. All temporary erosion and sediment control BMPs shall be removed within 30 days after the final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs or vegetation shall be permanently stabilized. 3.1.12 Element#12 —Manage the Project Erosion and sediment control BMPs for this project have been designed based on the following principles: ■ Design the project to fit the existing topography, soils, and drainage patterns. ■ Emphasize erosion control rather than sediment control. ■ Minimize the extent and duration of the area exposed. ■ Keep runoff velocities low. 14 Stormwafer Pollution Prevention Plan ■ Retain sediment on site. ■ Thoroughly monitor site and maintain all ESC measures. ■ Schedule major earthwork during the dry season. I As this project site is located west of the Cascade Mountain Crest, the project will be managed � according to the following key project components: ', Phasing of Construction ■ The construction project is being phased to the extent practicable in order to prevent soil erosion, and, to the maximum extent possible, the transport of sediment from the site during construction. ■ Revegetation of exposed areas and maintenance of that vegetation shall be ', an integral part of the clearing activities during each phase of construction, per the Scheduling BMP (C 162). Seasonal Work Limitations ■ From October 1 through April 30, clearing, grading, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt-laden runoff will be prevented from leaving the site through a combination of the following: ❑ Site conditions including existing vegetative coverage, slope, soil type, and proximity to receiving waters; and ❑ Limitations on activities and the extent of disturbed areas; and ❑ Proposed erosion and sediment control measures. ■ Based on the information provided and/or local weather conditions, the local permitting authority may expand or restrict the seasonal limitation on site disturbance. ■ The following activities are exempt from the seasonal clearing and grading � limitations: '�, ❑ Routine maintenance and necessary repair of erosion and sediment I control BMPs; I l� I Stormwater Pollution Prevention Plan ❑ Routine maintenance of public facilities or existing utility structures that do not expose the soil or result in the removal of the vegetative cover to soil; and ❑ Activities where there is 100 percent infiltration of surface water runoff within the site in approved and installed erosion and sediment control facilities. Coordination with Utilities and Other Jurisdictions ■ Care has been taken to coordinate with utilities, other construction projects, and the local jurisdiction in preparing this SWPPP and scheduling the construction «�ork. Inspection and Monitoring ■ All BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function. Site inspections shall be conducted by a person who is knowledgeable in the principles and practices of erosion and sediment control. This person has the necessary skills to: ❑ Assess the site conditions and construction activities that could impact the quality of stormwater, and ❑ Assess the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. ■ A Certified Erosion and Sediment Control Lead shall be on-site or on-call at all times. ■ VVhenever inspection and/or monitoring reveals that the BMPs identified in this SWPPP are inadequate, due to the actual discharge of or potential to discharge a significant amount of any pollutant, appropriate BMPs or design changes shall be implemented as soon as possible. Maintaining an Updated Construction SWPPP ■ This SWPPP shall be retained on-site or within reasonable access to the site. ■ The SWPPP shall be modified whenever there is a change in the design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the state. 16 Stormwater Po!lution Prevention Plan ■ The SWPPP shall be modified if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater '� discharges from the site. The SWPPP shall be modified as necessary to � include additional or modified BMPs designed to correct problems identified. Revisions to the SWPPP shall be completed within seven (7) days following the inspection. II t� ' Stormwater Pollutron Prevention Plan 4.0 Construction Phasing and BMP Implementation The BMP implementation schedule will be driven by the construction schedule. The follo�ving provides a sequential list of the proposed construction schedule milestones and the corresponding BMP implementation schedule. The list contains key milestones such as wet season construction. The BMP implementation schedule listed below is keyed to proposed phases of the construction project, and reflects differences in BMP installations and inspections that relate to wet season construction. The project site is located west of the Cascade Mountain Crest. As such, the dry season is considered to be from May 1 to September 30 and the wet season is considered to be from October 1 to April 30. ■ Estimate of Construction start date: TBD ■ Estimate of Construction finish date: TBD ■ Mobilize equipment on site: TBD ■ Mobilize and store all ESC and soil stabilization products (store materials on hand BMP C 150): TBD ■ Install ESC measures: TBD ■ Install stabilized construction entrance: TBD 'i ■ Begin clearing and grubbing: TBD I ■ Demolish existing one-story building structure: TBD ■ Excavation for building foundations TBD ■ Soil stabilization on excavated sideslopes (in idle, no work areas as shown on ESC plans) TBD ■ Temporary erosion control measures (hydroseeding) TBD ■ Site inspections reduced to monthly: TBD ■ Begin concrete pour and implement BMP C 151: TBD ■ Excavate and install new utilities and services (Phase 1): TBD ■ Begin building construction: TBD l9 Stormwater Po!lution Prevention Plan ■ Complete Phase 1 utility construction TBD ■ Begin implementing soil stabilization and sediment control BMPs throughout the site in preparation for wet season: TBD . Wet Season starts: 10 /O1 /2014 ■ Site inspections and monitoring conducted weekly and for applicable rain events as detailed in Section 6 of this SWPPP: TBD ■ Implement Element#12 BMPs and manage site to minimize soil disturbance during the wet season TBD ■ No site work such as grading or excavation planned: ■ Drv Season starts: 05 /O1 / 2015 ■ Site grading begins: TBD ■ Excavate and install new utilities and services (Phase 2): TBD • Site grading ends: TBD ■ Building construction complete: TBD ■ Final landscaping and planting begins: TBD ■ Permanent erosion control measures (hydroseeding): TBD �o Stormwater Pollution Prevention Plan 5.0 Pollution Prevention Team 5.1 Roles and Responsibilities The pollution prevention team consists of personnel responsible for implementation of the SWPPP, including the following: ■ Certified Erosion and Sediment Control Lead (CESCL)—primary contractor contact, responsible for site inspections (BMPs, visual monitoring, sampling, etc.); to be called upon in case of failure of any ESC measures. ■ Resident Engineer— For projects with engineered structures only (sediment pondsitraps, sand filters, etc.): site representative for the owner that is the project's supervising engineer responsible for inspections and issuing instructions and drawings to the contractor's site supervisor or representative ■ Emergency Ecology Contact — individual to be contacted at Ecology in case of emergency. ■ Emergency Owner Contact— individual that is the site owner or representative of the site o��ner to be contacted in the case of an emergency. ■ Non-Emergency Ecology Contact—individual that is the site owner or representative of the site owner than can be contacted if required. ■ Monitoring Personnel—personnel responsible for conducting water quality monitoring; for most sites this person is also the Certified Erosion and Sediment Control Lead. 5.2 Team Members Names and contact information for those identified as members of the pollution prevention team are provided in the following table. Title Name{s) Phone Number Certified Erosion and Sediment Control Lead(CESCL) TBD TBD Resident Engineer TBD TBD Emergency Ecology Contact TBD TBD Emergency Oumer Contact TBD TBD �� Stormwater Pollufion Prevention PJan Non-Emergency Ecology Contact TBD TBD Monitoring Personnel TBD TBD 22 Stormwater Pollution Prevention Plan 6.0 Site Inspections and Monitoring ' Monitoring includes visual inspection, monitoring for water quality parameters of concern, and documentation of the inspection and monitoring findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: ■ A record of the implementation of the SWPPP and other permit requirements; ■ Site inspections; and, ■ Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring fortns included in this SWPPP include the required information for the site log book. This SWPPP may function as the , site log book if desired, or the forms may be separated and included in a separate site log book. ', However, if separated,the site log book but must be maintained on-site or within reasonable ' access to the site and be made available upon request to Ecology or the local jurisdiction. 6.1 Site Inspection �, All BMPs will be inspected, maintained, and repaired as needed to assure continued performance I of their intended function. The inspector will be a Certified Erosion and Sediment Control Lead (CESCL) per BMP C 160. The name and contact information for the CESCL is provided in Section 5 of this SWPPP. Site inspection will occur in all areas disturbed by construction activities and at all stormwater discharge points. Stormwater will be examined for the presence of suspended sediment, turbidity, discoloration, and oily sheen. The site inspector will evaluate and document the effectiveness of the installed BMPs and determine if it is necessary to repair or replace any of the BMPs to improve the quality of stormwater discharges. All maintenance and repairs will be documented in the site log book or forms provided in this document. All new BMPs or design changes will be documented in the SWPPP as soon as possible. 6.1.1 Site Inspection Frequency Site inspections will be conducted at least once a week and within 24 hours following any discharge from the site. For sites with temporary stabilization measures, the site inspection frequency can be reduced to once every month. 6.1.2 Site Inspection Documentation The site inspector will record each site inspection using the site log inspection forms provided in Appendix E. The site inspection log forms may be separated from this SWPPP document, but �� Stormwater Pollution Prevention Plan will be maintained on-site or within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. 6.2 Stormwater Quality Monitoring Monitoring requirements for the proposed project will include either turbidity or water transparency sampling to monitor site discharges for water quality compliance with the 2005 Construction Stormwater General Permit (Appendix D). Sampling will be conducted at all discharge points at least once per calendar week. Turbidity or transparency monitoring will follow the analytical methodologies described in Section S4 of the 2005 Construction Stormwater General Permit(Appendix D). The key benchmark turbidity value is 25 nephelometric turbidity units (NTU) for the downstream receiving water body. lf the 25 NTU benchmark is exceeded in any sample collected from CBS, the following steps will be conducted: 1. Ensure all BMPs specified in this SWPPP are installed and functioning as intended. 2. Assess whether additional BMPs should be implemented, and document modified BMPs in the SWPPP as necessary. 3. Sample discharge daily until the discharge is 25 NTU or lower. If the turbidity exceeds 250 NTU at any time, the following steps will be conducted: 1. Notify Ecology by phone within 24 hours of analysis (see Section 5.0 of this SWPPP for contact information). 2. Continue sampling daily until the discharge is 25 NTU or lower Initiate additional treatment BMPs such as off-site treatment, infiltration, filtration and chemical treatment within 24 hours, and implement those additional treatment BMPs as soon as possible, but within a minimum of 7 days. 3. Describe inspection results and remedial actions taken in the site log book and in monthly discharge monitoring reports as described in Section 7.0 of this SWPPP. 6.2.2 pH Sampling Stormwater runoff will be monitored for pH starting on the first day of any activity that includes more than 40 yards of poured or recycled concrete, or after the application of"Engineered Soils" such as, Portland cement treated base, cement kiln dust, or fly ash. This does not include fertilizers. For concrete ��ork, pH monitoring will start the first day concrete is poured and 24 Stormwater Pollution Preventron Plan continue until 3 weeks after the last pour. For engineered soils, the pH monitoring period begins ' when engineered soils are first exposed to precipitation and continue until the area is fully I stabilized. i Stormwater samples will be collected weekly from all points of discharge from the site and ' measured far pH using a calibrated pH meter, pH test kit, or wide range pH indicator paper. If the measured pH is 8.5 or greater, the following steps will be conducted: 1. Prevent the high pH water from entering storm drains or surface water. 2. Adjust or neutralize the high pH water if necessary using appropriate technology such as COZ sparging (liquid or dry ice). 3. Contact Ecology if chemical treatment other than CO� sparging is planned. �� Stormwater Pollution Prevention Plan 7.0 Reporting and Recordkeeping 7.1 Recordkeeping 7.1.1 Site Log Book A site log book will be maintained for all on-site construction activities and will include: ■ A record of the implementation of the SWPPP and other permit requirements; ■ Site inspections; and, ■ Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring forms included in this SWPPP include the required information for the site log book. 7.1.2 Records Retention Records of all monitoring information (site log book, inspe�ction reports/checklists, etc.), this Stormwater Pollution Prevention Plan, and any other documentation of compliance with pennit requirements will be retained during the life of the construction project and for a minimum of three years following the termination of permit coverage in accordance with permit condition SS.C. 7.1.3 Access to Plans and Records The SWPPP, General Permit, Notice of Authorization letter, and Site Log Book will be retained on site or within reasanable access to the site and will be made immediately available upon request to Ecology or the local jurisdiction. A copy of this SWPPP will be provided to Ecology within 14 days of receipt of a written request for the SWPPP from Ecology. Any other information requested by Ecology will be submitted within a reasonable time. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with permit condition SS.G. 7.1.4 Updating the SWPPP In accordance with Conditions S3, S4.B, and S9.B.3 of the General Permit, this SWPPP will be modified if the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwatcr discharges from the site or there has been a change in design, construction, operation, ' or maintenance at the site that has a significant effect on the discharge, or potential for discharge, of pollutants to the waters of the State. The SWPPP will be modified within seven days of determination based on inspection(s) that additional or modified BMPs are necessary to correct problems identified, and an updated timeline for BMP implementation will be prepared. 27 Stormwater Pollution Prevention Plan 7.2 Reporting 7.2.1 Discharge Monitoring Reports If cumulative soil disturbance is 5 acres or larger: Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. Of there was no discharge during a given monitoring period, the Permittee shall submit the form as required, with the words "No discharge" entered in the place of monitoring results. The DMR due date is 15 days following the end of each month. 7.2.2 Notification of Noncompliance If any of the terms and conditions of the permit are not met, and it causes a threat to human health or the environment, the following steps will be taken in accordance with permit section SS.F: 1. Ecology will be immediately notified of the failure to comply. 2. Immediate action will be taken to control the noncompliance issue and to correct the problem. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five(5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Any time turbidity sampling indicates turbidity is 250 nephelometric turbidity units (NTU) or greater or water transparency is 6 centimeters or less, the Ecology regional office will be notified by phone within 24 hours of analysis as required by permit condition SS.A (see Section 5.0 of this SWPPP for contact information). In accordance «�ith permit condition S4.F.6.b, the Ecology regional office will be notified if chemical treatment other than CO� sparging is planned for adjustment of high pH water(see Section 5.0 of this SWPPP for contact information). 7.2.3 Permit Application and Changes In accordance with permit condition S2.A, a complete application form will be submitted to Ecology and the appropriate local jurisdiction (if applicable) to be covered by the General Permit. 28 Stormwafer Pollufion Prevention Plan Appendix A — Site Plans 29 ZZ �`. '; � '°r w �L `w,� /- -� �1a �� a�'�n��r ^: F ''�r""�,y'I:� -��*4`�i.'r"�'�u � `�+i t'R ".%MF r r�^ a �p '�k�±,�.„��W "�.,q*«��y, 5��..«-��- �a �Y-v� �� } "%Tz ��y`� I" � � W � �{� .`w �"°"P '-� ,, 1�,.,, ! v«i��'"�4�.��+"` .�..r• v- ,.,,,,,"r'� �' �` .� , F„a�s` f`�3�k� . . � .��``"�"'y��.'��." � O '3 � : . W W �.,,� �'�" ...} ,`. 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I � �N ; � �, �,.r X ' 4 I , . d o , ��„� � D¢b&I.I / �� a � L"—"—'_--'—"—"_'--"—"—" "—"—"—" "—"—"—"—"—"—"—"_'e �� C`7' f T a � � �. � y s � r� � ' ... i j ...:j,_ ��'' � Existing vault to treat � � � � , _. , I all construction runoff ,,, i ��;�R . , � ,� ,� . , Ie,i � ' � F � ��. 1 C-.�1 —. . . � : . ' I � a� F' � < • ° ♦ f � t . . •,- ��1 " i i ,. .... .. 1 n __.rw"_.r�o"'rw'— ' '. . .wa wr.�..�.ir r � � .iw.'_" '.'ip. a .w - . � ��r.�� i _ .. - + . . ��.�.--�. ...... ..�-��«.-�� .� �+ � y.. _'"'._. � — . ' ' . \\ ; � . .a_. : '' 1 . � °"•. \�� I // I� T ''.(�,�I I -e '� � � ' �,-��t ��.. n, � .. , ., � � $cale: I" = 80' cou�H�iNPORTERLUNDEEN Figure 2 - TESC Plan 801 SECOND AVENUE,SUITE 900 / SEATTLE,WA 981�4 P 206.343.0460 / F 206.343.5691 / cplinc.com Table 2-Developed Site Conditions Area Breakdown Land Cover Area Description Impervious Area 7.15 acres Building roof, parking areas, drive aisles,fire lane Pervious&Landscape 0.84 acres Associated landscaping, undisturbed areas Total Project Area 7.99 acres Total site area Percentage of Impervious Area 89% Existing Drainage Lake Washington Existing Outfall to Tunnel - Discharge to Lake Washington Lake Washington ' --------------- ---,--r- __ . .- �-�_---� -- ---------------------------�------------------- -_---- __ _..�._ - r : , - - - - - r �, ��.:�.�- �: , , � i ' i 1 ! .,.ti-.. �. .{.. 1° �l , � _ � ._, ; � � � � � e ; �L� � �' � � : tJ i } I / \'' � I �Y \\ � \\�� I '�� Boeing Property I�� ` ' The Hotel at \ �� : � , , I�4�/� i \\\ �.': 'r'' �� ` ! Southport � � !;��',; r , � :��;� , ;� \ � -. \ :`: ' �. � � � `' � !� , � � � �� Phase 1 Development , �� \, , � � , i : � � � , �; � '� i:;.,.� Stormfilter Manhole � �'` ' ' Porte�Cochere �� Loadfing Area . (treated by (treated by exi�ting wetva � � -- _ ' � Existing wet vault � StormFilter � \,,_ .`` � , � � ; , . cartridges) 1 •; �1 installed w�th Phase 1 n . I' �� ' � -� development , ;. � ' , � , ,.� ' � --.-1 � ' �� treated J91@pm , I ischarge �� - . . . _ _ _ - ��\ ' �'�� -- ./ ' i . � ;�� ,y _ - � '.(f�'� � / iw � I �� ' / • �— I WeL vaulC , � , � �%� . _ _9 ' � �� . ��'. ''a �� "�' I � � j /�^� ' • � '' ` i high flow _�— _y , _ �� '•, �. � ��.,._y:,_.�,_ � discharge I II \� ! I � ' �� Pumped � � � � � � � n , � � ; � � � � � _ ' ' ' Connection �� , , , �. ��. , � � ,, ..�� - _ ______________.. ;�) .'_�_______________ ________ ____1 I_.. `��. «. to existing ! � ; � ' Sur�ace Par ing Lot � � �` f � r� ' � � � � � � . ♦, (treated in existing ault) ; i storm stub �� y ,�_,- � I -� ` � � ; ,__-___ .� _..`._ _._ .__ � -— i ' , y,!' � _ � � �. o , � , � � ; � ,- _ _ __ ' �I 1�,"/-� n- � n _ � I , � � , � � � ________ ..i ._.__ " ____ _.."."..I I �_..... � _ I ...__. . . . /� ___ 1_'. ._. .. —} ..�...,..,... � , i � � _ — � —�j.1'..�_E�u.L _..�_.L_—l.._......,_ .� i �� . � i i 4 T 4:/1 ! ' ' �tti� i� t I � I � �; f , � - i I � i i � . � �' t � 1 I I ¢t: ��:,\ � I I i y �.� � � _ � � _. . I �'. I ii �, 1� �::/ � I � I � I 1 I $+' I � I i y I � � f I � I 1 1 i � I H : . �,. . I I I I I � � ` _ __. _.. y___________ _______________Ir______ _ I 1 .._____ __________ ____1________________ _______________ I " i I � 5 � I � PSE Upstream � � , ; `�� `� p I I I p � a ; Drainage Bypass ! _ ; ° � � '�; I'� , � � ,� � , , , _ __ ,�,� , , � � � � � '. . ...L-_- .�y ---_ I 1 / � _. � i Y I i � i i .._.. �.__ �..::_:.. .'"'I� � i i M i � ' .� . '._ _ I i i p � I i . „ '" ___-._ � . __.. _....._"" -�:._- �.-- �] ;' � � � Existing vault to PSE Property be reused for basic treatment of parking lot . Scale: I" = 80' cou�H�iNPORTERLUNDEEN Figure 3 - Proposed Conditions 801 SECOND AVENUE,SUITE 900 / SEATTLE,WA 98104 P 206.343.0460 / F 206.343.5691 / cplinc.corn Stormwater Pollution Prevention Plan Appendix B — Construction BMPs 30 BMP C103: High Visibility Fence Purpose Fencing is intended to: 1. Restrict clearing to approved limits. 2. Prevent disturbance of sensitive areas, their buffers, and other areas required to be left undisturbed. 3. Limit construction traffic to designated construction entrances, exits, or internal roads. 4. Protect areas where marking with survey tape may not provide adequate protection. Conditiofts of Use To establish clearing limits plastic, fabric, or metal fence may be used: • At the boundary of sensitive areas, their buffers, and other areas required to be left uncleared. • As necessary to control vehicle access to and on the site. Design a�zd High visibility plastic fence shall be composed of a high-density �I ]nstallation polyethylene material and shall be at least four feet in height. Posts far �� Specifications the fencing shall be steel or wood and placed every 6 feet on center (maximum) or as needed to ensure rigidity. The fencing shall be fastened to the post every six inches with a polyethylene tie. On long continuous lengths of fencing, a tension wire or rope shall be used as a top stringer to , prevent sagging between posts. The fence color shall be high visibility , orange. The fence tensile strength shall be 3601bsJft. using the ASTM ', D4595 testing method. '� If appropriate install fabric silt fence in accordance with BMP C233 to act as high visibility fence. Silt fence shall be at least 3 feet high and must be highly visible to meet the requirements of this BMP. Metal fences shall be designed and installed according to the manufacturer's specifications. Metal fences shall be at least 3 feet high and must be highly visible. � Fences shall not be wired or stapled to trees. Maintenaface If the fence has been damaged or visibility reduced, it shall be repaired or Standards replaced immediately and visibility restored. l'olurne II— Constr�itctiojz Stormwater•Pollutiori Pi-everitiorz -Attgust 2012 , 4-6 BMP C105: Stabilized Construction Entrance / Exit Purpose Stabilized Construction entrances are established to reduce the amount of sediment transported onto paved roads by vehicles or equipment. This is done by constructing a stabilized pad of quarry spalls at entrances and exits for construction sites. Conditions of Use Construction entrances shall be stabilized wherever traffic will be entering or leaving a construction site if paved roads or other paved areas are within 1,000 feet of the site. For residential construction provide stabilized construction entrances for each residence, rather than only at the main subdivision entrance. Stabilized surfaces shall be of sufficient length/width to provide vehicle access/parking, based on lot size/configuration. On large commercial, highway, and road projects, the designer should include enough extra materials in the contract to allow for additional stabilized entrances not shown in the initial Construction SWPPP. It is difficult to determine exactly where access to these projects will take place; additional materials will enable the contractor to install them where needed. Design and See Figure 4.1.1 for details. Note: the 100' minimum length of the Installation entrance shall be reduced to the maximum practicable size when the size Specifications or configuration of the site does not allow the full length (100'). Construct stabilized construction entrances with a 12-inch thick pad of 4- inch to 8-inch quarry spalls, a 4-inch course of asphalt treated base (ATB), or use existing pavement. Do not use crushed concrete, cement, or calcium chloride for construction entrance stabilization because these products raise pH levels in stormwater and concrete discharge to surface waters of the State is prohibited. A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the following standards: Grab Tensile Strength (ASTM D4751) 200 psi min. Grab Tensile Elongation (ASTM 30% max. D4632) Mullen Burst Strength (ASTM 400 psi min. D3786-80a) AOS (ASTM D4751) 20-45 (U.S. standard sieve size) • Consider early installation of the first lift of asphalt in areas that will paved; this can be used as a stabilized entrance. Also consider the installation of excess concrete as a stabilized entrance. During large concrete pours, excess concrete is often available for this purpose. Volume li—Constnrction Stormwater Pollution Prevention -August 2012 4-7 • Fencing (see BMP C103) shall be installed as necessary to restrict traffic to the construction entrance. • Whenever possible, the entrance shall be constructed on a firm, compacted subgrade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. • Construction entrances should avoid crossing existing sidewalks and back of walk drains if at all possible. If a construction entrance must cross a sidewalk or back of walk drain, the full length of the sidewalk and back of walk drain must be covered and protected from sediment leaving the site. �� Maintenance Quarry spalls shall be added if the pad is no longer in accordance with Standards the specifications. • If the entrance is not preventing sediment from being tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may include replacement/cleaning of the existing quarry spalls, street sweeping, an increase in the dimensions of the entrance, or the installation of a wheel wash. • Any sediment that is tracked onto pavement shall be removed by shoveling or street sweeping. The sediment collected by sweeping shall be removed or stabilized on site. The pavement shall not be cleaned by washing down the street, except when high efficiency sweeping is ineffective and there is a threat to public safety. If it is necessary to wash the streets, the construction of a small sump to contain the wash water shall be considered. The sediment would then be washed into the sump where it can be controlled. • Perform street sweeping by hand or with a high efficiency sweeper. Do not use a non-high efficiency mechanical sweeper because this creates dust and throws soils into storm systems or conveyance ditches. • Any quarry spalls that are loosened from the pad, which end up on the roadway shall be removed immediately. • If vehicles are entering or exiting the site at points other than the construction entrance(s), fencing (see BMP C 103) shall be installed to control traffic. • Upon project completion and site stabilization, all construction accesses intended as permanent access for maintenance shall be permanently stabilized. Volcsrne II—Coristruction Sto��rriu�ater Pollutiof� Preveration -Augcrst 2012 4-8 Driveway shall meet the requiremenls of the permitting agency It is recommended that the entrance be crowned so that runoff drains off the pad _�� .. � �' Install driveway culvert'rf there is a roadside ditch present '� 4'—8'auam soalls ' ;� , y �i Geotextile ±_ -' � 12"min.thickness � ` � � � Provide full width of inqresslegress area Figure 4.1.1 —Stabilized Construction Entrance Approved as Ecology has approved products as able to meet the requirements of BMP Equivalent C 105. The products did not pass through the Technology Assessment Protocol—Ecology (TAPE)process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at http:i iwww.ecv.wa.�/programs/wq/stormwater/newtech/equivalent.html BMP C106: Wheel Wash Purpose Wheel washes reduce the amount of sediment transported onto paved roads by motor vehicles. Conditions of Use When a stabilized construction entrance (see BMP C 105) is not preventing sediment from being tracked onto pavement. • Wheel washing is generally an effective BMP when installed with careful attention to topography. For example, a wheel wash can be detrimental if installed at the top of a slope abutting a right-of-way where the water from the dripping truck can run unimpeded into the street. Volurne II—Construction Sta�nwater Pollution Prevention -August 2012 4-9 • Pressure washing combined with an adequately sized and surfaced pad with direct drainage to a large 10-foot x 10-foot sump can be very effective. • Discharge wheel wash or tire bath wastewater to a separate on-site treatment system that prevents discharge to surface water, such as closed-loop recirculation or upland land application, or to the sanitary sewer with local sewer district approval. • Wheel wash or tire bath wastewater should not include wastewater from concrete washout areas. � Desigii and Suggested details are shown in Figure 4.1.2. The Local Permitting Installation Authority may allow other designs. A minimum of 6 inches of asphalt Specifications treated base (ATB) over crushed base material or 8 inches over a good subgrade is recommended to pave the wheel wash. Use a low clearance truck to test the wheel wash before paving. Either a belly dump or lowboy will work well to test clearance. Keep the water level from 12 to 14 inches deep to avoid damage to truck hubs and filling the truck tongues with water. Midpoint spray nozzles are only needed in extremely muddy conditions. _� I Wheel wash systems should be designed with a small grade change, 6- to j 1-inches for a 10-foot-wide pond, to allow sediment to flow to the low '� side of pond to help prevent re-suspension of sediment. A drainpipe with a �', 2- to 3-foot riser should be installed on the low side of the pond to allow ', for easy cleaning and refilling. Polymers may be used to promote coagulation and flocculation in a closed-loop system. Polyacrylamide (PAM) added to the wheel wash water at a rate of 0.25 - 0.5 pounds per 1,000 gallons of water increases effectiveness and reduces cleanup time. If PAM is already being used for dust or erosion control and is being applied by a water truck, the same truck can be used to change the wash water. Maintenance The wheel wash should start out the day with fresh water. ' Standards The wash water should be changed a minimum of once per day. On large earthwork jobs where more than 10-20 trucks per hour are expected, the wash water will need to be changed more often. Volume II—Construction Stormwater Pollution Prevention -August 2012 4-10 6' SEWER PIPE WfTH 3' TR/LSH PUMP WfTH FLOATS BUTT'ERFLY VALVES A ON SUC'T10N HOSE 2" SCHEDULE 40 8'x8' SUMP WfTH 5� 1-�/2' SCHEDULE 40 OF GTCH FOR SPRAYERS 2� i � MIDPOINT SPRAY NOZZLES SLOP� SLOPEy- S$OPE � � �F NEEDE 2x SLOPE � � � � �'� 6� .�.TB CONSTRUCTION SLOPE ENTRMICE 15' ATB APRON TO PROTECT A gqLL yqLy� GROUND FROM SPLASHING WATER ASPH/�LT CURB ON THE 6� SLEEVE UNDER ROAD LOW ROAD SIDE TO DIRECT W/�TER BACK TO POND p�w viEw 15' 15' 20' 15' S0' . CURB � 6' SLEEVE ELEVA710N VIEW LOCATE INVERT OF TOP PIPE 1' ABOVE BOTTOM OF WHEEL WASH 18. 8'x8' SUMP WATER LEVEL � 3' 5' 12' �DROJN PIPE 1:� SLOPE SECTION A-A �- NOTES: 1- BUILD 8'x8' SUMP TO ACCOMODATE CLEANING BY TRACKHOE. Figure 4.1.2—Wheel Wash Notes: 1. Asphalt consmzction entrance 6 in.asphalt treated base(ATB). 2. 3-inch h�ash pump with floats on the suction hose. 3. Midpoint spray nozzles,if needed. 4. 6-inch sewer pipe with butterfly valves.Bottom one is a drain. Locate top pipe's invert 1 foot above bottom of wheel wash. 5. 8 foot x 8 foot sump with 5 feet of catch.Build so the sump can be cleaned with a trackhoe. 6. Asphalt curb on the low road side to direct water back to pond. 7. 6-inch sleeve under road. 8. Ball valves. 9. 15 foot.ATB apron to protect ground from splashing water. Yolume II—Coristr•t�ction Stor-natiti�ater�Pollution Preveration -At�gust 2012 4-11 BMP C107: Construction Road/Parking Area Stabilization I I Purpose Stabilizing subdivision roads, parking areas, and other on-site vehicle � i transportation routes immediately after grading reduces erosion caused by '� construction traffic or runoff. � Conditions of Use Roads or parking areas shall be stabilized wherever they are constnicted, ' whether permanent or temporary, for use by construction traffic. . High Visibility Fencing (see BMP C 103) shall be installed, if necessary, to limit the access of vehicles to only those roads and parking areas that are stabilized. ', Design and • On areas that will receive asphalt as part of the project, install the first ' Installation lift as soon as possible. ' Specifications A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed • surfacing base course shall be applied immediately after grading or utility installation. A 4-inch course of asphalt treated base (ATB) may also be used, or the road/parking area may be paved. It may also be possible to use cement or calcium chloride for soil stabilization. If cement or cement kiln dust is used for roadbase stabilization, pH monitoring and BMPs (BMPs C252 and C253) are necessary to evaluate and minimize the effects on stormwater. If the area will not be used for permanent roads, parking areas, or structures, a 6-inch depth of hog fuel may also be used, but this is likely to require more maintenance. Whenever possible, construction roads and parking areas shall be placed on a firm, compacted subgrade. • Temporary road gradients shall not exceed 15 percent. Roadways shall be carefully graded to drain. Drainage ditches shall be provided on each side of the roadway in the case of a crowned section, or on one side in the case of a super-elevated section. Drainage ditches shall be directed to a sediment control BMP. • Rather than relying on ditches, it may also be possible to grade the road so that runoff sheet-flows into a heavily vegetated area with a ' well-developed topsoil. Landscaped areas are not adequate. If this area has at least 50 feet of vegetation that water can flow through, then it is I generally preferable to use the vegetation to treat runoff, rather than a sediment pond or trap. The 50 feet shall not include wetlands or their � buffers. If runoff is allowed to sheetflow through adjacent vegetated areas, it is vital to design the roadways and parking areas so that no concentrated runoff is created. ', • Storm drain inlets shall be protected to prevent sediment-laden water ' entering the storm drain system(see BMP C220). ' .�laintenance Inspect stabilized areas regularly, especially after large storm events. Standards Crushed rock, gravel base, etc. shall be added as required to maintain a Volume II—Cor�struction Stormwater Pollcttiorr Prevention -August 2012 I� 4-1? stable driving surface and to stabilize any areas that have eroded. Following construction, these areas shall be restored to pre-construction condition or better to prevent future erosion. Perform street cleaning at the end of each day or more often if necessary. Volume II—Coristruction Stor•mwater Polli�tion Preverrtion -August 2012 4-13 BMP C120: Temporary and Permanent Seeding Purpose Seeding reduces erosion by stabilizing exposed soils. A well-established vegetative cover is one of the most effective methods of reducing erosion. Conditiotis of Use Use seeding throughout the project on disturbed areas that have reached final grade or that will remain unworked for more than 30 days. � The optimum seeding windows for western Washington are April 1 � through June 30 and September 1 through October 1. I Between July 1 and August 30 seeding requires irrigation until 75 percent '� grass cover is established. Bett�veen October 1 and March 30 seeding requires a cover of mulch with straw or an erosion control blanket until 75 percent grass cover is established. Review all disturbed areas in late August to early September and complete all seeding by the end of September. Otherwise, vegetation will not establish itself enough to provide more than average protection. • Mulch is required at all times for seeding because it protects seeds from heat, moisture loss, and transport due to runoff. Mulch can be applied on top of the seed or simultaneously by hydroseeding. See BMP C121: Mulchin� for specifications. • Seed and mulch, all disturbed areas not otherwise vegetated at final , site stabilization. Final stabilization means the completion of all soil , disturbing activities at the site and the establishment of a permanent vegetative cover, or equivalent permanent stabilization measures (such as pavement, riprap, gabions or geotextiles)which will prevent , erosion. Design and Seed retention/detention ponds as required. Installation Install channels intended for vegetation before starting major Specifications earthwork and hydroseed with a Bonded Fiber Matrix. For vegetated channels that will have high flows, install erosion control blankets over hydroseed. Before allowing water to flow in vegetated channels, establish 75 percent vegetation cover. If vegetated channels cannot be established by seed before water flow; install sod in the channel bottom—over hydromulch and erosion control ' blankets. ' Volume II– Constr•uction StonnK�ater Pollution Prevention -August 2012 4-13 • Confirm the installation of all required surface water control measures to prevent seed from washing away. • Hydroseed applications shall include a minimum of 1,500 pounds per acre of mulch with 3 percent tackifier. See BMP C 121: Mulchin� for specifications. • Areas that will have seeding only and not landscaping may need compost or meal-based mulch included in the hydroseed in order to establish vegetation. Re-install native topsoil on the disturbed soil �, surface before application. I • When installing seed via hydroseeding operations, only about 1/3 of I the seed actually ends up in contact with the soil surface. This reduces ', the ability to establish a good stand of grass quickly. To overcome this, consider increasing seed quantities by up to 50 percent. • Enhance vegetation establishment by dividing the hydromulch operation into ri�vo phases: 1. Phase 1- Install all seed and fertilizer��rith 25-30 percent mulch and tackifier onto soil in the first lift. 2. Phase 2- Install the rest of the mulch and tackifier over the first lift. Or, enhance vegetation by: 1. Installing the mulch, seed, fertilizer, and tackifier in one lift. 2. Spread or blow stra�v over the top of the hydromulch at a rate of 800-1000 pounds per acre. 3. Hold straw in place with a standard tackifier. Both of these approaches will increase cost moderately but will greatly improve and enhance vegetative establishment. The increased cost may be offset by the reduced need for: • Irrigation. • Reapplication of mulch. • Repair of failed slope surfaces. � This technique works with standard hydromulch (1,500 pounds per acre minimum) and BFM/MBFMs (3,000 pounds per acre minimum). • Seed may be installed by hand if: • Temporary and covered by straw, mulch, or topsoil. • Permanent in small areas (usually less than l acre) and covered with mulch, topsoil, or erosion blankets. • The seed mixes listed in the tables below include recommended mixes for both temporary and permanent seeding. Volume II—Construction Stor-rnwater Pollution Prevef�tion -Augasst 2012 4-14 • Apply these mixes, with the exception of the wetland mix, at a rate of 120 pounds per acre. This rate can be reduced if soil ', amendments or slow-release fertilizers are used. • Consult the local suppliers or the local conservation district for ' their recommendations because the appropriate mix depends on a variety of factors, including location, exposure, soil type, slope, and expected foot traffic. Alternative seed mixes approved by the I, local authority may be used. , • Other mixes may be appropriate, depending on the soil type and hydrology of the area. • Table 4.l.2 lists the standard mix for areas requiring a temporary ' vegetative cover. ' Table 4.1.2 Temporary Erosion Control Seed Mix %Wei ht % Puritv %Germination ' Chewings or annual blue grass 40 98 90 Festuca rubra var. commutata or Poa anna Perennial rye - 50 98 90 Lolium erenne Redtop or colonial bentgrass 5 92 85 ' A rostis alba or A rostis tenuis ; White dutch clover 5 98 90 �I Tri olium re ens �'� • Table 4.1.3 lists a recommended mix for landscaping seed. Table 4.1.3 �' Landscaping Seed Mix I� %Wei ht %Puri � %Germination Perennial rye blend 70 98 90 Lolium erenne Chewings and red fescue blend 30 98 90 Festuca rubra var. commutata or Festuca rzsbYa Volurne II—Construction Stormwater Pollutio�i Pr-everrtio�r -Atsgerst Z01? 4-1_5 • Table 4.1.4 lists a turf seed mix for dry situations where there is no need for watering. This mix requires very little maintenance. Table 4.1.4 Low-Growing Turf Seed Mix % Wei ht % Purit�- %Germination Dwarf tall fescue (several varieties) 45 98 90 Festuca arundinacea var. Dwarf perennial rye (Barclay) 30 98 90 Loliu�n erenne var. barcla � Red fescue 20 98 90 Festuca rubra Colonial bentgrass 5 98 90 A rostis tenuis • Table 4.1.5 lists a mix for bioswales and other intermittently wet areas. Table 4.1.5 Bioswale Seed Mix* %«'ei ht % Puritv %Germination Tall or meadow fescue 75-80 98 90 Festuca arundinacea or Festuca elatior Seaside/Creeping bentgrass 10-15 92 85 A rostis alustris Redtop bentgrass 5-10 90 80 A rostis alba or A rostis i antea *Modified Briargreen, Inc. Hl'droseeding Guide Wetlands Seed Mix Volume II—Constr�uction Stor•�yzivater Pollutiori Prevention -August 2012 4-16 • Table 4.1.6 lists a low-growing, relatively non-invasive seed mix appropriate for very wet areas that are not regulated wetlands. Apply this mixture at a rate of 60 pounds per acre. Consult Hydraulic Permit Authority (HPA) for seed mixes if applicable. Table 4.1.6 Wet Area Seed Mix* %VVei ht %Puriri %Germination Tall or meadow fescue 60-70 98 90 Festuca arundinacea or Festuca elatior Seaside/Creeping bentgrass 10-15 98 85 A rostis alustris Meadow foxtail 10-15 90 80 Ale ocurus ratensis Alsike clover 1-6 98 90 Tri olium h bridum Redtop bentgrass 1-6 92 85 A rostis alba * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix • Table 4.1.71ists a recommended meadow seed mix for infrequently maintained areas or non-maintained areas where colonization by native plants is desirable. Likely applications include rural road and utility right-of-way. Seeding should take place in September or very early October in order to obtain adequate establishment prior to the winter months. Consider the appropriateness of clover, a fairly invasive species, in the mix. Amending the soil can reduce the need for clover. Table 4.1.7 Meadow Seed Mix %R'ei ht %Puritv %Germination Redtop or Oregon bentgrass 20 92 85 Agrostis alba or Agrostis ore onensis Red fescue 70 98 90 Festuca rubra White dutch clover 10 98 90 Tri oliufn re ens Volurne II—Construction Stormwater Pollution Preverrtiorr -.Atsgatst 2012 4-17 • Roughening and Rototilling: • The seedbed should be firm and rough. Roughen all soil no matter what the slope. Track walk slopes before seeding if engineering purposes require compaction. Backblading or smoothing of slopes greater than 4H:1 V is not allowed if they are to be seeded. • Restoration-based landscape practices require deeper incorporation than that provided by a simple single-pass rototilling treatment. Wherever practical, initially rip the subgrade to improve long-term permeability, infiltration, and water inflow qualities. At a minimum, permanent areas shall use soil amendments to achieve organic matter and permeability performance defined in engineered soil/landscape systems. For systems that are deeper than 8 inches complete the rototilling process in multiple lifts, or prepare the engineered soil system per specifications and place to achieve the specified depth. • Fertilizers: • Conducting soil tests to determine the exact type and quantity of fertilizer is recommended. This will prevent the over-application of fertilizer. • Organic matter is the most appropriate form of fertilizer because it provides nutrients (including nitrogen, phosphorus, and potassium) in the least water-soluble form. • In general, use l 0-4-6 N-P-K(nitrogen-phosphorus-potassium) fertilizer at a rate of 90 pounds per acre. Always use slow-release fertilizers because they are more efficient and have fewer environmental impacts. Do not add fertilizer to the hydromulch machine, or agitate, more than 20 minutes before use. Too much agitation destroys the slow-release coating. • There are numerous products available that take the place of chemical fertilizers. These include several with seaweed extracts that are beneficial to soil microbes and organisms. If 100 percent cottonseed meal is used as the mulch in hydroseed, chemical fertilizer may not be necessary. Cottonseed meal provides a good source of long-term, slow-release, available nitrogen. • Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix: • On steep slopes use Bonded Fiber Matrix (BFM) or Mechanically Bonded Fiber Matrix (MBFM) products. Apply BFM/MBFM products at a minimum rate of 3,000 pounds per acre of mulch with approximately 10 percent tackifier. Achieve a minimum of 95 percent soil coverage during application. Numerous products are available commercially. Installed products per manufacturer's instructions. Most products require 24-36 hours to cure before rainfall and cannot be installed on wet or saturated soils. Volurr�e II—Construction Stonnwater Pollution Prevention -August 2012 4-18 Generally, products come in 40-50 pound bags and include all necessary ingredients except for seed and fertilizer. • BFMs and MBFMs provide good alternatives to blankets in most areas requiring vegetation establishment. Advantages over blankets include: �� • BFM and MBFMs do not require surface preparation. • Helicopters can assist in installing BFM and MBFMs in remote areas. • On slopes steeper than 2.SH:1V, blanket installers may require ropes and harnesses for safety. • Installing BFM and MBFMs can save at least $1,000 per acre compared to blankets. Maintenance Reseed any seeded areas that fail to establish at least 80 percent cover Standards (100 percent cover for areas that receive sheet or concentrated flows). If reseeding is ineffective, use an alternate method such as sodding, mulching, or nets/blankets. If winter weather prevents adequate grass growth, this time limit may be relaxed at the discretion of the local authority when sensitive areas would otherwise be protected. • Reseed and protect by mulch any areas that experience erosion after achieving adequate cover. Reseed and protect by mulch any eroded area. ' • Supply seeded areas with adequate moisture, but do not water to the �' extent that it causes runoff. � Approved as Ecology has approved products as able to meet the requirements of BMP ' Equivalent C 120. The products did not pass through the Technology Assessment ', Protocol—Ecology (TAPE) process. Local jurisdictions may choose not to � accept this praduct approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at http:!;%www.ecy.wa.�programs/wq/storm��ater/newtech/equivalent.html Volume II— Construction Stormwater Pollutzon Preverztion -August 2012 4-19 BMP C151: Concrete Handling Purpose Concrete work can generate process water and slurry that contain fine particles and high pH, both of which can violate water quality standards in the receiving water. Concrete spillage or concrete discharge to surface waters of the State is prohibited. Use this BMP to minimize and eliminate concrete, concrete process water, and concrete slurry from entering waters of the state. Conditions of Use Any time concrete is used, utilize these management practices. Concrete construction projects include, but are not limited to, the following: • Curbs • Sidewalks • Roads • Bridges • Foundations • Floors • Runways Design and • Wash out concrete truck chutes, pumps, and internals into formed Installation areas only. Assure that washout of concrete trucks is performed off- Volurne II— Constrcrction Stormx�ater Pollution Prevention -August 2012 4-42 Specifications site or in designated concrete washout areas. Do not wash out concrete I trucks onto the ground, or into storm drains, open ditches, streets, or streams. Refer to BMP C 154 for information on concrete washout areas. • Return unused concrete remaining in the truck and pump to the originating batch plant for recycling. Do not dump excess concrete on site, except in designated concrete washout areas. , • Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats, and trowels into formed areas only. • Wash equipment difficult to move, such as concrete pavers in areas that do not directly drain to natural or constructed stormwater conveyances. • Do not allow washdown from areas, such as concrete aggregate driveways, to drain directly to natural or constructed stormwater conveyances. • Contain washwater and leftover product in a lined container when no formed areas are available,. Dispose of contained concrete in a manner that does not violate ground water or surface water quality standards. • Always use forms or solid barriers for concrete pours, such as pilings, within 15-feet of surface waters. • Refer to BMPs C252 and C253 for pH adjustment requirements. • Refer to the Construction Stormwater General Permit for pH monitoring requirements if the project involves one of the following activities: • Significant concrete work (greater than 1,000 cubic yards poured concrete or recycled concrete used over the life of a project). • The use of engineered soils amended with (but not limited to) Portland cement-treated base, cement kiln dust or fly ash. • Discharging stormwater to segments of water bodies on the 303(d) list(Category 5) for high pH. Mai�ztenance Check containers for holes in the liner daily during concrete pours and Standards repair the same day. Polttme II— Corrsn-c�ction Stof•rml�ater Pollution Prevention -August 2012 4-43 BMP C160: Certified Erosion and Sediment Control Lead Purpose The project proponent designates at least one person as the responsible representative in charge of erosion and sediment control (ESC), and water quality protection. The designated person shall be the Certified Erosion and Sediment Control Lead (CESCL) who is responsible for ensuring compliance with all local, state, and federal erosion and sediment control and water quality requirements. Co►:ditio►zs of Use A CESCL shall be made available on projects one acre or larger that discharge stormwater to surface waters of the state. Sites less than one acre may have a person without CESCL certification conduct inspections; sampling is not required on sites that disturb less than an acre. • The CESCL shall: • Have a current certificate proving attendance in an erosion and sediment control training course that meets the minimum ESC training and certification requirements established by Ecology(see details below). Ecology will maintain a list of ESC training and certification providers at: http J/www.ec��pro�rams/wq/stormwater/cescl.htm l OR • Be a Certified Professional in Erosion and Sediment Control (CPESC); for additional information go to: www.cpesc.net Specifications • Certification shall remain valid for three years. • The CESCL shall have authority to act on behalf of the contractor or developer and shall be available, or on-call, 24 hours per day throughout the period of construction. • The Construction SWPPP shall include the name, telephone number, fax number, and address of the designated CESCL. • A CESCL may provide inspecrion and compliance services for multiple construction projects in the same geographic region. Duties and responsibilities of the CESCL shall include, but are not limited to the following: • Maintaining permit file on site at all times which includes the Construction SWPPP and any associated permits and plans. • Directing BMP installation, inspection, maintenance, modification, and removal. Volume II—Construction StormwateY Pollution Prevention -August 2012 4-53 • Updating all project drawings and the Construction SWPPP with ' changes made. • Completing any sampling requirements including reporting results ' using WebDMR. • Keeping daily logs, and inspection reports. Inspection reports should include: • Inspection date/time. � • Weather information; general conditions during inspection and � approximate amount of precipitation since the last inspection. , . A summary or list of all BMPs implemented, including observations of all erosion/sediment control structures or practices. The following shall be noted: 1. Locations of BMPs inspected. 2. Locations of BMPs that need maintenance. 3. Locations of BMPs that failed to operate as designed or intended. 4. Locations of where additional or different BMPs are required. . Visual monitoring results, including a description of discharged stormwater. The presence of suspended sediment, turbid water, discoloration, and oil sheen shall be noted, as applicable. • Any water quality monitoring performed during inspection. • General comments and notes, including a brief description of any BMP repairs, maintenance or installations made as a result of the inspection. • Facilitate, participate in, and take corrective actions resulting from inspections performed by outside agencies or the owner. BMP C162: Scheduling Purpose Sequencing a construction project reduces the amount and duration of soil exposed to erosion by wind, rain, runoff, and vehicle tracking. Conditions of Use The construction sequence schedule is an orderly listing of all major land- disturbing activities together with the necessary erosion and sedimentation control measures planned for the project. This type of schedule guides the contractor on work to be done before other work is started so that serious erosion and sedimentation problems can be avoided. Following a specified work schedule that coordinates the timing of land- ' disturbing activities and the installation of control measures is perhaps the most cost-effective way of controlling erosion during construction. The removal of surface ground cover leaves a site vulnerable to accelerated i'olume II— Construction Stormwater Pollution Prevention-August 2012 I 4-54 erosion. Construction procedures that limit land clearing provide timely installation of erosion and sedimentation controls, and restore protective cover quickly can significantly reduce the erosion potential of a site. Design • Minimize construction during rainy periods. Considerations Schedule projects to disturb only small portions of the site at any one . time. Complete grading as soon as possible. Immediately stabilize the disturbed portion before grading the next portion. Practice staged seeding in order to revegetate cut and fill slopes as the work progresses. Volume II—Construction Stormwater Pollution Prevention -August 2012 � 4-55 4.2 Runoff Conveyance and Treatment BMPs This section contains the standards and specifications for Runoff Conveyance and Treatment BMPs. Table 4.2.1, below, shows the relationship of the BMPs in Section 4.2 to the Construction Stormwater Pollution Prevention Plan (SWPPP) Elements described in Section 3.3.3. Table 4.2.1 Runoff Conveyance and Treatment BMPs by SWPPP Element Element A1 E lert�en[�! Elertient� E lertien[Afi E��t� E lemen[iKJ E lement�F71 E lement X12 E lemen[#13 BAAP orElement Name ��rve Esiadis� StadNze Protect Stabilize Contrd Maintan IAanaqe Ne P��a Low NegetationMAark Construdion Sa7s Sbpes Channels poNutants BMPs Project �� q� ve nt BAIP C101: Preserving NaNral lkqet�ion ✓ B AIP C 102:Butter Zon es ✓ ✓ BMP C1D3:Hgh Visibility Plastic or Metal � � Fence BGPC105: StabiNzeOConstruction � E nVance!E xit 861P C106: Wheel Wrsh ✓ BIAP C107: Construction RoadrPartdng � ea Stab�izmon BMP C120:Temporary a�Permanent � � Seedi� 86W C121: Mul�ng ✓ ✓ BMP C172: Nets and BWnkets ✓ ✓ � BMPCID: PlasticCovering ✓ � BMP C11M: $oddiny ✓ BtdP C125: TopsoiYn9/Compostinq ✓ II � BMP C126: Poyacrylanide for Soil Erosion � I Protection I IB►IP C13D: SuAace Roughening ✓ ✓ I BIAP C131: GraAfent Terraces ✓ ✓ I BMP C110: Dus[Contrd ✓ I BMP C150: Yatenals On Hand ✓ ✓ BGIP C151: Coacrete HaadYnq ✓ I BMP C14: Sawcutting and SuAadng � �, Pol�ution Prevention BMP C153: Mate�al Delivery,Swrage and � �I C on tanme nt BMP C154: Concrete VWs�outArea ✓ BMP C160: CerUlied Ero9oa aid � � SedimentC ontrd Lead BhIP C162:ScDeduYnq ✓ volume 11—Construction Stormwater Pollution Prevention -August 2012 � , 4-56 � � BMP C220: Storm Drain Inlet Protection PurPose Storm drain inlet protection prevents coarse sediment from entering drainage systems prior to permanent stabilization of the disturbed area. Conditions of Use Use storm drain inlet protection at inlets that are operational before permanent stabilization of the disturbed drainage area. Provide protection for all storm drain inlets downslope and within S00 feet of a disturbed or construction area, unless conveying runoff entering catch basins to a sediment pond or trap. Also consider inlet protection for lawn and yard drains on new home construction. These small and numerous drains coupled with lack of gutters in new home construction can add significant amounts of sediment into the roof drain system. If possible delay installing lawn and yard drains until just before landscaping or cap these drains to prevent sediment from entering the system until completion of landscaping. Provide 18-inches of sod around each finished lawn and yard drain. Table 4.2.2 lists several options for inlet protection. All of the methods for storm drain inlet protection tend to plug and require a high frequency of maintenance. Limit drainage areas to one acre or less. Possibly provide emergency overflows with additional end-of-pipe treatment where stormwater ponding would cause a hazard. Volt�me II— Cortstructio�t Stormtia�ater Polh�tiorz Preventio�a -August 2012 4-79 Table 4.2.2 Storm Drain Inlet Protection Applicable for Type of Inlet Emergency Paved/Earthen �� Protection Overflow Surfaces Conditions of Use I Dro Inlet Protection � Excavated drop inlet Yes, Earthen Applicable for heavy flows. Easy �, protection temporary to maintain. Large area , flooding will Requirement: 30' X 30'/acre ', occur Block and gravel drop Yes Paved or Earthen Applicable for heavy concentrated , inlet protection flows. Will not ond. , Gravel and wire drop No Applicable for heavy concentrated inlet protection flows. Will pond. Can withstand traff"ic. Catch basin filters Yes Paved or Earthen Fre uent maintenance re uired. Curb Inlet Protection Curb inlet protection Small capacity Paved Used for sturdy, more compact with a wooden weir overflow installation. Block and gravel curb Yes Paved Sturdy�, but limited filtration. inlet protection Culvert Inlet Protection Culvert inlet sediment 18 month expected life. tra Design and Excavated Drop Inlet Protection - An excavated impoundment around the , Installation storm drain. Sediment settles out of the stormwater prior to entering the Speci�cations storm drain. • Provide a depth of 1-2 ft as measured from the crest of the inlet structure. I • Slope sides of excavation no steeper than 2H:1 V. • Minimum volume of excavation 35 cubic yards. • Shape basin to fit site with longest dimension oriented toward the �i longest inflow area. • Install provisions for draining to prevent standing water problems. • Clear the area of all debris. • Grade the approach to the inlet uniformly. • Drill weep holes into the side of the inlet. • Protect weep holes with screen wire and washed aggregate. • Seal weep holes when removing structure and stabilizing area. Volume 11—Construction Stor»iwater Pollc�tiorr Preverition -:4�sgust 2012 4-80 • Build a temporary dike, if necessary, to the down slope side of the structure to prevent bypass flow. Block and Gravel Filter- A barrier formed around the storm drain inlet with standard concrete blocks and gravel. See Fi�ure 4.2.8. • Provide a height of 1 to 2 feet above inlet. • Recess the first row 2-inches into the ground for stability. • Support subsequent courses by placing a 2x4 through the block opening. • Do not use mortar. • Lay some blocks in the bottom row on their side for dewatering the pool. • Place hardware cloth or comparable wire mesh with '/2-inch openings over all block openings. • Place gravel just below the top of blocks on slopes of 2H:1 V or flatter. • An alternative design is a gravel donut. • Pr i n inl 1 f H•1 ov de a et s ope o 3 . V. • Provide an outlet slope of 2H:1 V. • Provide a 1-foot wide level stone area between the structure and the inlet. • Use inlet slope stones 3 inches in diameter or larger. • Use gravel '/z- to 3/4-inch at a minimum thickness of 1-foot for the outlet slope. Volunze ll— Constructiori Storrmti�ater Pollution Prevention -Attgust 2012 4-81 Plan View A Drain GJv� �,,,.�, o Grate °�� c��'✓c� J��s=c�c o��o� ��o�C'�'"O �'O�, G�a�'�G� �o�'o��,, Q o-;� (�� '.�_s,aC�C��o� :��oo�jo�aVVCn`�C-o O�>�) ��O �1 d.J \/�O,�yrJ��OL��lO e^��J �J�OC��%ov��O�OV . ��GO�;�/p � ,�/�c�e vLi a�uO°O O' C3� �°/�, ��,.��",� a�� °�; Cancrete co o � ��"��oo�� ,��o, �� Block :��Q�� 0 �� °�o�� 0 °�� 0 � ��o� � �;;�o o °� �c' �C4J��'� � �o�� '"lJ`'oo-��-n�c� o-: o�,�� ° o009 ��° Gravel ��;�� -��'�C�� C�� Backfill � Oo _04�`o vl Q� �/`3�r,��,.��1 ,.. �J o� �-O°`Oo° Oco04�"�0�� '�o��oo �'��"o�� G�Co�O�a� ��O�oC�joc v � �� o�o ��V o��°,�o��eG r ��,55��oQ�' p1 ��o Seetion A ' Iy Concrete Block�, Wire Screen or /� Filter Fabric Gravel Backfill�, Overtlow � / —� Water �� %�o� '� G Ponding Height �C��B�;� � WaterJ �'��o�Cc �r�o� �o 00 jj��A�� _ ��/�� \��\��\��\�� Drop Inlet \\�\\�\\�\��\\ �\// , �/��/� //�//� j//� \ \ ��%�/j ��/i��%� �� '1; Notes: 1. Drop inlet sediment barriers are to be used for small,nearly level drainage areas.(less than 5%) 2. Excavate a basin of sufficient size adjacent to the drop inlet. 3.The top of the strvcture(ponding height)must be well below the ground elevation downslope to prevent runoff from bypassing the inlet.A temporary dike may be necessary on the downslope side of the structure. Figure 4.2.8—Block and Gravel Filter �, Gravel and Wire Mesh Falter- A gravel bamer placed over the top of the inlet. This structure does not provide an overflow. • Use a hardware cloth or comparable wire mesh with '/2-inch openings. • Use coarse aggregate. • Provide a height 1-foot or more, 18-inches wider than inlet on all sides. • Plac�e wire mesh over the drop inlet so that the wire extends a minimum of 1-foot beyond each side of the inlet structure. • Overlap the strips if more than one strip of inesh is necessary. Volurne II—Construction Stormwater-Pollcttion Preventiori -.August 2012 4-8? • Place coarse aggregate over the wire mesh. • Provide at least a 12-inch depth of gravel over the entire inlet opening and extend at least 18-inches on all sides. Catchbasin Filters —Use inserts designed by manufacturers for construction sites. The limited sediment storage capacity increases the amount of inspection and maintenance required, which may be daily for heavy sediment loads. To reduce maintenance requirements combine a catchbasin filter with another type of inlet protection. This type of inlet protection provides flow bypass without overflow and therefore may be a better method for inlets located along active rights-of-way. • Provides 5 cubic feet of storage. • Requires dewatering provisions. • Provides a high-flow bypass that will not clog under normal use at a construction site. • Insert the catchbasin filter in the catchbasin just below the grating. Curb Inlet Protection with Wooden Weir—Barrier formed around a curb inlet with a wooden frame and gravel. • Use wire mesh with '/2-inch openings. • Use extra strength filter cloth. • Construct a frame. • Attach the wire and filter fabric to the frame. • Pile coarse washed aggregate against wire/fabric. • Place weight on frame anchors. Block and Gravel Curb Inlet Protection—Barrier formed around a curb inlet with concrete blocks and gravel. See Figure 4.2.9. • Use wire mesh with '/2-inch openings. • Place two concrete blocks on their sides abutting the curb at either side of the inlet opening. These are spacer blocks. • Place a 2x4 stud through the outer holes of each spacer block to align the front blocks. • Place blocks on their sides across the front of the inlet and abutting the spacer blocks. • Place wire mesh over the outside vertical face. • Pile coarse aggregate against the wire to the top of the barrier. Curb and Gutter Sediment Barrier—Sandbag or rock berm (riprap and aggregate) 3 feet high and 3 feet wide in a horseshoe shape. See F�ure 4.2.10. Volume 77—Consmsction Stormwater Pollution Prevention -August 2012 4-83 • Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 feet high and 3 feet wide, at least 2 feet from the inlet. • Construct a horseshoe shaped sedimentation trap on the outside of the berm sized to sediment trap standards for protecting a culvert inlet. '� Mai�zterlanee • Inspect catch basin filters frequently, especially after storm events. �, Standu��ds Clean and replace clogged inserts. For systems with clogged stone ' filters: pull away the stones from the inlet and clean or replace. An ' alternative approach would be to use the clogged stone as fill and put fresh stone around the inlet. • Do not wash sediment into storm drains while cleaning. Spread all excavated material evenly over the surrounding land area or stockpile and stabilize as appropriate. Approved as Ecology has approved products as able to meet the requirements of BMP Equivaler:t C220. The products did not pass through the Technology Assessment Protocol —Ecology (TAPE)process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at http://w��.ecy.wa.gov/pro�rams/wq/stormwater/newtech/equivalent.html Volurne II— Coristruction Stor�mtivater Pollution Prevention -August 2012 4-84 Plan View � Back of Sidewalk A - Catch Basin �, ll� �'�� II I 11 I� 2x4 Wood Stud Back of Curb Concrete Block Curb Inlet �G �o 04�� o.o� a°V`."4b- '�� ! o.��c�° '� °� b, � �o�°'o �� ,,��C>o. ��o� '� �� /�� i � 4°o'C'�e� �'� ' 'eb.Q �1��,�°o� I ,�+ �J.-u`J�}, � �r p a o.p ��c�,��R�c'G� �'� ��d��T��a•�g,,�R°'�?. ��1��''�/p�✓o� � .� o ,0, o o ^0, �R7a^ a qd�4`�:V �ti,�ao•,o',�,co � oo ,s.p�p L��c. •0.0. o ,lo�oo•c•p• o•O;o c ati.7�� - n `�a �._.. e Q ��,a�,d��p��.� a��g��2�� c�� B,S�`O�,S�a°��o��,S?� �� 4°�J��JaQ, g�J°� . .°,'J�oCO?,� °Qo.Oa'J<` 4p��C`�'-.e�0o°�,,.4�J' �o'o�°• b�-ss:oe p�. e• r o;�.•�� o•eq�o' • Co�'•c•pe•��o o� � �`apL_V O o . p�C� o�` o�-� o Q�o��to o�. �c- a�,�� .,:-�r.. p .��ti, �c.,c�,�,.,.o �x . , � � �o ;w . wire Screen or A Filter Fabric Concrete Block Section A — A '�''Drain Gravel ' (20mm) '/,"Drain Gravel (20mm) Ponding Height Concrete Block Overflow ' o.•��'� I R •, : .. ' , ' : � � �� \��/� � .� \� . Curb Inlet \�//\ \ Wire Screen or \�/��\//�\�/��/�� Filter Fabric �/��i� // 4 Wood Stud \\ Catch Basin \/' (100x50 Timber Stud) �j ��/ NOTES: 1.Use block and gravel type sediment barrier when curb inlet is located in gently sloping street segment, where water can pond and allow sediment to separate from runoff. 2. Barrier shall allow for overflow from severe storm event. 3.Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed from the traveled way immediately. Figure 4.2.9— Block and Gravel Curb Inlet Protection Volume II— Construction Stormwater Pollution Prevention -August 2012 4-85 i Plan V ew , -- _ _ _ � � Back of Sidewalk ! 'I Burlap Sacks to Catch Basin , Overlap onto Curb �� Curb Inlet � i� i' -- -'� Back of Curb �i �� ,, �`I i '�.i i �� RUNOFF �li �'T` �I ---�1� RUNOFF SPILLWAY!;r;�;' ' ,h; ,�� \"/ F, V ! / /�1� / / / � / �� i � �'�,'.�`�.� j%/ ,,. �/;,� , Gravel Filled Sandbags � , _/,%; Stacked Tightly NOTES: 1.Place curb type sediment barriers on gently sloping street segments,where water can pond and allow sedixnent to separate from runoff. 2.Sandbags of either burlap or woven'geotextile'fabric,are filled with gravel,layered and packed tightly. 3.Leave a one sandbag gap in the top row to provide a spiliway for overflow. 4.Inspect barriers and remove sediment after each storm event.Sediment and gravel must be removed from the traveled way immediately. Figure 4.2.10—Curb and Gutter Barrier Volume II—Constntction Stormwater Pollution Prevention -August 2012 4-86 Stormwater Pollutron Prevention Plan Appendix C — Alternative BMPs The following includes a list of possible alternative BMPs for each of the 12 elements not described in the main SWPPP text. This list can be referenced in the event a BMP for a specific element is not functioning as designed and an alternative BMP needs to be implemented. Element#1 - Mark Clearing Limits Element#2 - Establish Construction Access Element#3 -Control Flow Rates ' Element#4 - Install Sediment Controls ' Straw Bale Barrier(BMP C230) Straw Wattles (BMP C235) Storm Drain Inlet Protection(BMP C220) Advanced BMPs: Element#5 - Stabilize Soils Preserving Natural Vegetation (BMP C 101) Element#6 - Protect Slopes Element#8 - Stabilize Channels and Outlets Channel Lining(BMP C202) Straw Wattles (BMP C235) Interceptor Dike and Swale (BMP C200) Element#10 -Control Dewatering Check Dams (BMP C207) Outlet Protection (BMP C209) Additional Advanced BMPs to Control Dewatering: 31 BMP C101: Preserving Natural Vegetation Purpose The purpose of preserving natural vegetation is to reduce erosion wherever practicable. Limiting site disturbance is the single most effective method for reducing erosion. For example, conifers can hold up to about 50 percent of all rain that falls during a storm. Up to 20-30 percent of this rain ma never reach the ound but is taken u b the tr r Y �' ee o eva orates. P Y P Another benefit is that the rain held in the tree can be released slo��vly to the ground after the storn�. Conditions of Use Natural vegetation should be preserved on steep slopes, near perennial and intermittent watercourses or swales, and on building sites in wooded areas. • As required by local governments. • Phase construction to preserve natural vegetation on the project site for as long as possible during the construction period. Design and Natural vegetation can be preserved in natural clumps or as individual Installation trees, shrubs and vines. Specifications The preservation of individual plants is more difficult because heavy equipment is generally used to remove unwanted vegetation. The points to remember when attempting to save individual plants are: • Is the plant worth saving? Consider the location, species, size, age,vigor, and the work involved. Local governments may also have ordinances to save natural vegetation and trees. • Fence or clearly mark areas around trees that are to be saved. It is preferable to keep ground disturbance away from the trees at least as far out as the dripline. Plants need protection from three kinds of injuries: • Construction Equipment- This injury can be above or below the ground level. Damage results from scarring, cutting of roots, and compaction of the soil. Placing a fenced buffer zone around plants to be saved prior to construction can prevent construction equipment injuries. • Grade Changes - Changing the natural ground level will alter grades, which affects the plant's ability to obtain the necessary air, «ater, and minerals. Minor fills usually do not cause problems although sensitivity between species does vary and should be checked. Trees can typically tolerate fill of 6 inches or less. For shrubs and other plants, the fill should be less. When there are major changes in grade, it may become necessary to supply air to the roots of plants. This can be done by placing a layer of gravel and a tile system over the roots before the fill is made. A tile system protects a tree from a raised grade. The tile system should be Volume II—Constn�ction Storrnwater Pollution Prevention -August 201 Z 4-3 laid out on the original grade leading from a dry well around the tree trunk. The system should then be covered with small stones to allow air to circulate over the root area. Lowering the natural ground level can seriously damage trees and shrubs. The highest percentage of the plant roots are in the upper 12 inches of the soil and cuts of only 2-3 inches can cause serious injury. To protect the roots it may be necessary to terrace the immediate area around the plants to be saved. If roots are exposed, construction of retaining walls may be needed to keep the soil in place. Plants can also be preserved by leaving them on an undisturbed, gently sloping mound. To increase the chances for survival, it is best to limit grade changes and other soil disturbances to areas outside the dripline of the plant. • Excavations- Protect trees and other plants when excavating for drainfields, power, water, and sewer lines. Where possible, the trenches should be routed around trees and large shrubs. When this is not possible, it is best to tunnel under them. This can be done with hand tools or with power augers. If it is not possible to route the trench around plants to be saved, then the following should be observed: Cut as few roots as possible. When you have to cut, cut clean. Paint cut root ends with a wood dressing like asphalt base paint if roots will be exposed for more than 24-hours. Backfill the trench as soon as possible. Tunnel beneath root systems as close to the center of the main trunk to preserve most of the important feeder roots. Some problems that can be encountered with a few specific trees are: • Maple, Dogwood, Red alder, Western hemlock, Western red ccdar, and Douglas fir do not readily adjust to changes in environment and special care should be taken to protect these trees. • The windthrow hazard of Pacific silver fir and madrona is high, while that of Western hemlock is moderate. The danger of windthrow increases where dense stands have been thinned. Other species (unless they are on shallow, wet soils less than 20 inches deep) have a low windthrow hazard. • Cottonwoods, maples, and willows have water-seeking roots. These can cause trouble in sewer lines and infiltration fields. On the other hand, they thrive in high moisture conditions that other trees would not. • Thinning operations in pure or mixed stands of Grand fir, Pacific silver fir, Noble fir, Sitka spruce, Western red cedar, Western hemlock, Pacific dogwood, and Red alder can cause serious disease problems. Disease can become established through damaged limbs, trunks, roots, i�'oli�me II— Constr��ctron Stormwater Pollution Prevention -August 2012 4-4 and freshly cut stumps. Diseased and weakened trees are also susceptible to insect attack. Maintenance Inspect flagged and/or fenced areas regularly to make sure flagging or� , Sta�idards fencing has not been removed or damaged. If the flagging or fencin� has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. • If tree roots have been exposed or injured, "prune" cleanly with an appropriate pruning saw or lopers directly above the darnaged roots and recover with native soils. Treatment of sap flowing trees (fir, hemlock, pine, soft maples) is not advised as sap forms a natural healing barrier. BMP C102: Buffer Zones Purpose Creation of an undisturbed area or strip of natural vegetation or an established suitable planting that will provide a living filter to reduce soil � erosion and runoff velocities. Conditions of Use Natural buffer zones are used along streams, wetlands and other bodies of water that need protection from erosion and sedimentation. Vegetative buffer zones can be used to protect natural swales and can be incorporated into the natural landscaping of an area. Critical-areas buffer zones should not be used as sediment treatment areas. These areas shall remain completely undisturbed. The local permitting authority may expand the buffer widths temporarily to allow the use of the expanded area for removal of sediment. Design and • Preserving natural vegetation or plantings in clumps, blocks, or strips Installation is generally the easiest and most successful method. Specifications Leave all unstable steep slopes in natural vegetation. . • Mark clearing limits and keep all equipment and construction debris out of the natural areas and buffer zones. Steel construction fencing is the most effective method in protecting sensitive areas and buffers. Alternatively, wire-backed silt fence on steel posts is marginally effective. Flagging alone is typically not effective. • Keep all excavations outside the dripline of trees and shrubs. • Do not push debris or extra soil into the buffer zone area because it will cause damage from burying and smothering. • Vegetative buffer zones for streams, lakes or other waterways shall be established by the local permitting authority or other state or federal permits or approvals. Maintenance Inspect the area frequently to make sure flagging remains in place and the Standards area remains undisturbed. Replace all damaged flagging immediately. Volume II— Construction Stormx�ater Polhstiorl Pr-eve�rtion -Atsgust 2012 4-� BMP C121: Mulching Purpose Mulching soils provides immediate temporary protection from erosion. Mulch also enhances plant establishment by conserving moisture, holding fertilizer, seed, and topsoil in place, and moderating soil temperatures. There is an enormous variety of mulches that can be used. This section discusses only the most common types of mulch. Conditions of Use As a temporary cover measure, mulch should be used: • For less than 30 days on disturbed areas that require cover. • At all times for seeded areas, especially during the wet season and i'oli�rne II—Constr-uction Storrntivater Pollution Prevention -August 2012 4-19 BMP C123: Plastic Covering Purpose Plastic covering provides immediate, short-term erosion protection to slopes and disturbed areas. Conditions of Plastic covering may be used on disturbed areas that require cover Use measures for less than 30 days, except as stated below. • Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note: The relatively rapid breakdown of most polyethylene sheeting makes it unsuitable for long-term (greater than six months) applications. • Due to rapid runoff caused by plastic covering, do not use this method upslope of areas that might be adversely impacted by concentrated runoff. Such areas include steep and/or unstable slopes. • Plastic sheeting may result in increased runoff volumes and velocities, requiring additional on-site measures to counteract the increases. Creating a trough with wattles or other material can convey clean water away from these areas. • To prevent undercutting, trench and backfill rolled plastic covering products. • While plastic is inexpensive to purchase, the added cost of installation, maintenance, removal, and disposal make this an expensive material, up to $1.50-2.00 per square yard. • Whenever plasric is used to protect slopes install water collection measures at the base of the slope. These measures include plastic- covered berms, channels, and pipes used to covey clean rainwater away from bare soil and disturbed areas. Do not mix clean runoff from a plastic covered slope with dirty runoff from a project. • Other uses for plastic include: 1. Temporary ditch liner. 2. Pond liner in temporary sediment pond. 3. Liner for bermed temporary fuel storage area if plastic is not reactive to the type of fuel being stored. 4. Emergency slope protection during heavy rains. 5. Temporary drainpipe ("elephant trunk") used to direct water. Design and • Plastic slope cover must be installed as follows: Installation 1. Run plastic up and down slope, not across slope. Specifications 2. Plastic may be installed perpendicular to a slope if the slope length is less than 10 feet. 3. Minimum of 8-inch overlap at seams. Volume II—Constr-iection Stormwater Pollution P�-evefrtion -.Atsgcrst 2012 4-26 4. On long or wide slopes, or slopes subject to wind, tape all seams. 5. Place plastic into a small (12-inch wide by 6-inch deep) slot trench at the top of the slope and backfill with soil to keep water from flowing underneath. 6. Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and tie them together with twine to hold them in place. 7. Inspect plastic for rips, tears, and open seams regularly and repair immediately. This prevents high velocity runoff from contacting bare soil which causes extreme erosion. 8. Sandbags may be lowered into place tied to ropes. However, all sandbags must be staked in place. • Plastic sheeting shall have a minimum thickness of 0.06 millimeters. • If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection shall be installed at the toe of the slope in order to reduce the velocity of runoff. Muintenance • Torn sheets must be replaced and open seams repaired. Standards Completely remove and replace the plastic if it begins to deteriorate • due to ultraviolet radiation. • Completely remove plastic when no longer needed. . Dispose of old tires used to weight down plastic sheeting appropriately. Approved as Ecology has approved products as able to meet the requirements of BMP Equivalent C 123. The products did not pass through the Technology Assessment Protocol —Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at http:%%www.ecv.wa. o�v/pro�rams/wq/stormwater/newtech/equivalent.html BMP C124: Sodding Purpose The purpose of sodding is to establish permanent turf for immediate erosion protection and to stabilize drainage ways where concentrated overland flow will occur. Conditions of Use Sodding may be used in the following areas: • Disturbed areas that require short-term or long-term cover. • Disturbed areas that require immediate vegetative cover. • All waterways that require vegetative lining. Waterways may also be seeded rather than sodded, and protected«ith a net or blanket. Voltsrne II—Cortsh•uctiort Storr�na�ater Pollution Prevention -August 2012 4-2 7 Design and Sod shall be free of weeds, of uniform thickness (approximately 1-inch I Installation thick), and shall have a dense root mat for mechanical strength. Specificatio��s The following steps are recommended for sod installation: • Shape and smooth the surface to final grade in accordance with the , approved grading plan. The swale needs to be overexcavated 4 to 6 I inches below design elevation to allow room for placing soil ' amendment and sod. • Amend 4 inches (minimum) of compost into the top 8 inches of the �� soil if the organic content of the soil is less than ten percent or the permeability is less than 0.6 inches per hour. See , http://www.ecy.wa.�pro�rams/swfa/or�anics/soil.html for further ', information. • Fertilize according to the supplier's recommendations. I, • Work lime and fertilizer 1 to 2 inches into the soil, and smooth the , surface. ' • Lay strips of sod beginning at the lowest area to be sodded and perpendicular to the direction of water flow. Wedge strips securely into place. Square the ends of each strip to provide for a close, tight fit. Stagger joints at least 12 inches. Staple on slopes steeper than 3H:1 V. Staple the upstream edge of each sod strip. • Roli the sodded area and irrigate. • When sodding is carried out in alternating strips or other patterns, seed the areas between the sod immediately after sodding. Maintenance If the grass is unhealthy, the cause shall be determined and appropriate Standards action taken to reestablish a healthy groundcover. If it is impossible to establish a healthy groundcover due to frequent saturation, instability, or some other cause, the sod shall be removed, the area seeded with an appropriate mix, and protected with a net or blanket. BMP C125: Topsoiling / Composting Purpose Topsoiling and composting provide a suitable growth medium for final �� site stabilization with vegetation. While not a permanent cover practice in , itself, topsoiling and composting are an integral component of providing � permanent cover in those areas where there is an unsuitable soil surface �, for plant growth. Use this BMP in conjunction with other BMPs such as ' seeding, mulching, or sodding. ' Native soils and disturbed soils that have been organically amended not only retain much more stormwater, but they also serve as effective biofilters for urban pollutants and, by supporting more vigorous plant growth, reduce the water, fertilizer and pesticides needed to support Volume II—Corlstruction Stor•rrnti�ater Pollution Prevention -Aargust 2012 4-28 BMP C140: Dust Control Purpose Dust control prevents wind transport of dust from disturbed soil surfaces onto roadways, drainage ways, and surface waters. Co�:ditions of Use • In areas (including roadways) subject to surface and air movement of dust where on-site and off-site impacts to roadways, drainage ways, or surface waters are likely. Design and • Vegetate or mulch areas that will not receive vehicle traffic. In areas Installation where planting, mulching, or paving is impractical, apply gravel or Specifications landscaping rock. • Limit dust generation by clearing only those areas where immediate activity will take place, leaving the remaining area(s) in the original condition. Maintain the original ground cover as long as practical. • Construct natural or artificial windbreaks or windscreens. These mav be designed as enclosures for small dust sources. • Sprinkle the site with water until surface is wet. Repeat as needed. To prevent carryout of mud onto street, refer to Stabilized Construction Entrance (BMP C 1 OS). • Irrigation water can be used for dust control. Irrigation systems should be installed as a first step on sites where dust control is a concern. • Spray exposed soil areas with a dust palliative, following the manufacturer's instructions and cautions regarding handling and application. Used oil is prohibited from use as a dust suppressant. Local governments may approve other dust palliatives such as calcium chloride or PAM. i • PAM (BMP C 126) added to water at a rate of 0.5 lbs. per 1,000 gallons of water per acre and applied from a water truck is more effective than water alone. This is due to increased infiltration of��ater into the soil and reduced evaporation. In addition, small soil particles are bonded together and are not as easily transported by wind. Adding PAM may actually reduce the quantity of water needed for dust controL Use of PAM could be a cost-effective dust control method. Techniques that can be used for unpaved roads and lots include: • Lower speed limits. High vehicle speed increases the amount of dust stirred up from unpaved roads and lots. • Upgrade the road surface strength by improving particle size, shape, and mineral types that make up the surface and base materials. • Add surface gravel to reduce the source of dust emission. Limit the amount of fine particles(those smaller than .075 mm) to 10 to 20 percent. Volume II—Construction Stormwater Pollution Prevention -August 2012 4-40 . —� • Use geotextile fabrics to increase the strength of new roads or roads ' undergoing reconstruction. • Encourage the use of alternate, paved routes, if available. • Restrict use of paved roadways by tracked vehicles and heavy trucks to prevent damage to road surface and base. • Apply chemical dust suppressants using the admix method, blending ' the product with the top few inches of surface material. Suppressants ' may also be applied as surface treatments. • Pave unpaved permanent roads and other trafficked areas. • Use vacuum street sweepers. • Remove mud and other dirt promptly so it does not dry and then turn into dust. • Limit dust-causing work on windy days. • Contact your local Air Pollution Control Authority for guidance and training on other dust control measures. Compliance with the local Air Pollution Control Authority constitutes compliance with this BMP. Maintenance Respray area as necessary to keep dust to a minimum. Standards BMP C150: Materials on Hand Purpose Keep quantities of erosion prevention and sediment control materials on the project site at all times to be used for regular maintenance and emergency situations such as unexpected heavy summer rains. Having these materials on-site reduces the time needed to implement BMPs when inspections indicate that existing BMPs are not meeting the Construction SWPPP requirements. In addition, contractors can save money by buying some materials in bulk and storing them at their office or yard. Conditions of Use • Construction projects of any size or type can benefit from having materials on hand. A small commercial development project could have a roll of plastic and some gravel available for immediate ' protection of bare soil and temporary berm construction. A large earthwork project, such as highway construction, might have several tons of straw, several rolls of plastic, flexible pipe, sandbags, geotextile fabric and steel "T"posts. • Materials are stockpiled and readily available before any site clearing, grubbing, or earthwork begins. A large contractor or developer could keep a stockpile of materials that are available for use on several proj ects. j • If storage space at the project site is at a premium, the contractor could �!, maintain the materials at their office ar yard. The office or yard must �, be less than an hour from the project site. i Volume II–Constnrction Storm�vater Pollt�tion Prevention -August 2012 I�� 4-41 Desig�r and Depending on project type, size, complexity, and length, materials and Installation quantities will vary. A good minimum list of items that will cover Specifications numerous situations includes: Material Clear Plastic, 6 mil Drain i e, 6 or 8 inch diameter Sandba s, filled Straw Bales for mulchin , ua S alls Washed Gravel Geotextile Fabric Catch Basin Inserts Steel "T"Posts Silt fence material Straw Wattles Maintenance • All materials with the exception of the quarry spalls, steel "T"posts, Standards and gravel should be kept covered and out of both sun and rain. • Re-stock materials used as needed. Volume II—Construction Stormwater Pollution Prevention -August 2012 4-42 �� BMP C200: Interceptor Dike and Swale Purpose Provide a ridge of compacted soil, ar a ridge ��ith an upslope swale, at the top or base of a disturbed slope or along the perimeter of a disturbed construction area to convey stormwater. Use the dike and/or swale to intercept the runoff from unprotected areas and direct it to areas where erosion can be controlled. This can prevent storm runoff from entering the work area or sediment-laden runoff from leaving the construction site. Conditions of L'se Where the runoff from an exposed site or disturbed slope must be conveyed to an erosion control facility which can safely convey the stormwater. • Locate upslope of a construction site to prevent runoff from entering disturbed area. ', • When placed horizontally across a disturbed slope, it reduces the ��, amount and velocity of runoff flowing down the slope. �, • Locate downslope to collect runoff from a disturbed area and direct water to a sediment basin. Design and • Dike andlor swale and channel must be stabilized with temporary or Installation permanent vegetation or other channel protection during construction. Speeifications Channel requires a positive grade for drainage; steeper grades require • channel protection and check dams. • Review construction for areas where overtopping may occur. • Can be used at top of new fill before vegetation is established. • May be used as a permanent diversion channel to carry the runoff. • Sub-basin tributary area should be one acre or less. • Design capacity for the peak flow from a 10-year, 24-hour storm, assuming a Type 1 A rainfall distribution, for temporary facilities. Alternatively, use 1.6 times the 10-year, 1-hour flow indicated by an approved continuous runoff model. For facilities that will also serve on a permanent basis, consult the local government's drainage requirements. Interceptor dikes shall meet the following criteria: Top Width 2 feet minimum. Height 1.5 feet minimum on berm. Side Slope 2H:1 V or flatter. Grade Depends on topography, however, dike system minimum is 0.5%, and maximum is 1%. Compaction Minimum of 90 percent ASTM D698 standard proctor. Yolztme II—Corrstruction Stor-rrttii-ater Pollutiort Preventioyz -August 2012 4-57 Horizontal Spacing of Interceptor Dikes: Average Slope Slope Percent Flowpath Length 20H:1 V or less 3-5% 300 feet (10 to 20)H:1 V 5-10% 200 feet (4 to 10)H:1 V 10-25% 100 feet (2 to 4)H:1 V 25-50% 50 feet �i� Stabilization depends on velocity and reach � Slopes<5% Seed and mulch applied within 5 days of dike construction (see BMP C121, Mulchin�). i, Slopes 5 -40% Dependent on runoff velocities and dike materials. Stabilization should be done immediately using either sod or riprap or other measures to avoid erosion. • The upslope side of the dike shall provide positive drainage to the dike outlet. No erosion shall occur at the outlet. Provide energy dissipation measures as necessary. Sediment-laden runoff must be released through a sediment trapping facility. • Minimize construction traffic over temporary dikes. Use temporary cross culverts for channel crossing. Interceptor swales shall meet the following criteria: Bottom Width 2 feet minimum; the cross-section bottom shall be level. Depth 1-foot minimum. Side Slope 2H:1 V or flatter. Grade Maximum 5 percent, with positive drainage to a suitable outlet (such as a sediment pond). Stabilization Seed as per BMP C 120, Temporary and , Permanent Seeding, or BMP C202, Channel Lining, 12 inches thick riprap pressed into the bank and extending at least 8 inches vertical from the bottom. • Inspect diversion dikes and interceptor swales once a week and after every rainfall. Immediately remove sediment from the flow area. • Damage caused by construction traffic or other activity must be repaired before the end of each working day. Check outlets and make timely repairs as needed to avoid gully formation. � When the area below the temporary diversion dike is permanently stabilized, remove the dike and fill and stabilize the channel to blend with � the natural surface. Volume II—Construction Stormwater Pollution Prevention -August 2012 4-58 BMP C202: Channel Lining Purpose To protect channels by providing a channel liner using either blankets or riprap. Conditions of When natural soils or vegetated stabilized soils in a channel are not adequat� Use to prevent channel erosion. • When a permanent ditch or pipe system is to be installed and a temporary measure is needed. • In almost all cases, synthetic and organic coconut blankets are more effective than riprap for protecting channels from erosion. Blankets can be used with and without vegetation. Blanketed channels can be designed to handle any expected flow and longevity requirement. Some synthetic blankets have a predicted life span of 50 years or more, even in sunlight. • Other reasons why blankets are better than rock include the availability of blankets over rock. In many areas of the state, rock is not easily obtainable or is very expensive to haul to a site. Blankets can be delivered anywhere. Rock requires the use of dump trucks to haul and heavy equipment to place. Blankets usually only require laborers with hand tools, and sometimes a backhoe. • The Federal Highway Administration recommends not using flexible liners whenever the slope exceeds 10 percent or the shear stress exceeds 8 lbs/ftZ. Design and See BMP C 122 for information on blankets. Installation Since riprap is used where erosion potential is high, construction must be Specifications sequenced so that the riprap is put in place with the minimum possible delay. • Disturbance of areas �vhere riprap is to be placed should be undertaken only when final preparation and placement of the riprap can follo�v immediately behind the initial disturbance. Where riprap is used for outlet protection, the riprap should be placed before or in conjunction with the construction of the pipe or channel so that it is in place when the pipe or channel begins to operate. • The designer, after determining the riprap size that will be stable under the flow conditions, shall consider that size to be a minimum size and then, based on riprap gradations actually available in the area, select the size or sizes that equal or exceed the minimum size. The possibility of drainage structure damage by children shall be considered in selecting a riprap size, especially if there is nearby water or a gully in which to toss the stones. • Stone for riprap shall consist of field stone or quarry stone of approximately rectangular shape. The stone shall be hard and angular Volume II—Consm�ction Storrnwater Pollution Prevention -.Augatst 2012 4-63 and of such quality that it will not disintegrate on exposure to water or weathering and it shall be suitable in all respects for the purpose intended. • A lining of engineering filter fabric (geotextile) shall be placed between the riprap and the underlying soil surface to prevent soil movement into or through the riprap. The geotextile should be keyed in at the top of the bank. • Filter fabric shall not be used on slopes greater than 1-1/2H:1V as slippage may occur. It should be used in conjunction with a layer of coarse aggregate (granular filter blanket) when the riprap to be placed is 12 inches and larger. BMP C203: Water Bars Pi�rpose A small ditch or ridge of material is constructed diagonally across a road or right-of-way to divert stormwater runoff from the road surface, wheel tracks, or a shallow road ditch. See Fi�ure 4.2.3. Conditions of use Clearing right-of-way and construction of access for power lines, pipelines, and other similar installations often require long narrow right-of-ways over sloping terrain. Disturbance and compaction promotes gully formation in these cleared strips by increasing the volume and velocity of runoff. Gully formation may be especially severe in tire tracks and ruts. To prevent gullying, runoff can often be diverted across the width of the right-of-way to undisturbed areas by using small predesigned diversions. • Give special considerarion to each individual outlet area, as well as to the cumulative effect of added diversions. Use gravel to stabilize the diversion where significant vehicular traffic is anticipated. Design and Height: 8-inch minimum measured from the channel bottom to the ridge top. Installation Side slope of channel: 2H:1 V maximum; 3H:1 V or flatter when Specifications • vehicles will cross. • Base width of ridge: 6-inch minimum. • Locate them to use natural drainage systems and to discharge into well vegetated stable areas. • Guideline for Spacing: Slope % Spacing(ft) < 5 125 5 - 10 l00 10 - 20 75 20 - 35 50 > 35 Use rock lined ditch Volurne/I— Constr-ctctiorr Stor•rnlvater Pollution Preverttion -August 2012 4-64 Treated 2"x10"may be abutted end to Spreader must be level end for max. spreader length of 50' 1" min. o" min. , _ _ � , � �- ��I � 5" min. �il li �_ �— � �—�� -�- =' ii��i ��-� ii' lli ��i_I � ;I_I n I i , 11=1 li� � �i i i � �iii I - - - � - - 18" min. rebar supports 8'max. spacing Figure 4.2.6–Detail of Level Spreader BMP C207: Check Dams Purpose Construction of small dams across a swale or ditch reduces the velocity of concentrated flow and dissipates energy at the check dam. Conditions of Use Where temporary channels or permanent channels are not yet vegetated, channel lining is infeasible, and/or velocity checks are required. • Check dams may not be placed in streams unless approved by the State , Department of Fish and Wildlife. Check dams may not be placed in � wetlands without approval from a permitting agency. I • Do not place check dams below the expected backwater from any ' salmonid bearing water between October 1 and May 31 to ensure that there is no loss of high flow refuge habitat for overwintering juvenile '� salmonids and emergent salmonid fiy. , • Construct rock check dams from appropriately sized rock. The rock , used must be large enough to stay in place given the expected design I flow through the channel. The rock must be placed by hand or by I, mechanical means (no dumping of rock to form dam) to achieve I complete coverage of the ditch or swale and to ensure that the center ' of the dam is lower than the edges. i • Check dams may also be constructed of either rock or pea-gravel filled ' bags. Numerous new products are also available for this purpose. They tend to be re-usable, quick and easy to install, effective, and cost efficient. • Place check dams perpendicular to the flow of water. • The dam should form a triangle when viewed from the side. This prevents undercutting as water flows over the face of the dam rather than falling directly onto the ditch bottom. volume II— Construction Sto�•mwater Pollution Preverrtion -August 2012 4-73 • Before installing check dams impound and bypass upstream water flow away from the work area. Options for bypassing include pumps, siphons, or temporary channels. • Check dams in association with sumps work more effectively at slowing flow and retaining sediment than just a check dam alone. A deep sump should be provided immediately upstream of the check dam. • In some cases, if carefully located and designed, check dams can remain as permanent installations with very minor regrading. They may be left as either spillways, in which case accumulated sediment would be graded and seeded, or as check dams to prevent further sediment from leaving the site. • The maximum spacing between the dams shall be such that the toe of the upstream dam is at the same elevation as the top of the downstream dam. • Keep the maximum height at 2 feet at the center of the dam. • Keep the center of the check dam at least 12 inches lower than the outer edges at natural ground elevation. • Keep the side slopes of the check dam at 2H:1 V or flatter. • Key the stone into the ditch banks and extend it beyond the abutments a minimum of 18 inches to avoid washouts from overflow around the dam. • Use filter fabric foundation under a rock or sand bag check dam. If a blanket ditch liner is used, filter fabric is not necessary. A piece of organic or synthetic blanket cut to fit will also work for this purpose. • In the case of grass-lined ditches and swales, all check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale - unless the slope of the swale is greater than 4 percent. The area beneath the check dams shall be seeded and mulched immediately after dam removal. • Ensure that channel appurtenances, such as culvert entrances below check dams, are not subject to damage or blockage from displaced stones. Figure 4.2.7 depicts a typical rock check dam. Maintenance Check dams shall be monitored for performance and sediment Standards accumulation during and after each runoff producing rainfall. Sediment shall be removed when it reaches one half the sump depth. • Anticipate submergence and deposition above the check dam and erosion from high flows around the edges of the dam. • If significant erosion occurs between dams, install a protective riprap liner in that portion of the channel. I'olt�fne /I— Corrstr-uctiofi Sto►•rntivater Polhstiort Preverttion -August 2012 4-74 Approved as Ecology has approved products as able to meet the requirements of BMP Equivalent C207. The products did not pass through the Technology Assessment Protocol —Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at � http:i%�v�vw.ecv.��'a.govlprorrams'��ti��istonn�vater;�ne�vtech�equivalent.html -� Volume II— Constr-uction Storrnwater Pollution Prever�tion -August 201? 4-75 View Looking Upstream 18�(0.5m) � . i�, Ii� 1 A � � � '� '� � � � � 12 (150mm) �I � �� G�+�`��9=;%,",' �Gvc;�, G;C�o, /� /: %��/��/ `v= . � � oJvv�o O�ti' �T c O `�` , j% ��°oQ D�o -o.o��,1�a�a��,//;/ 24 (0.6m) o� NOTE: ` �°c�-"�-�a�oogc�°' 1 Key stone into channel banks and �,�� / / / extend it beyond the abutments a �'\� �\'��\�\ minimum of 18" (0.5m)to prevent A flow around dam. Section A - A FLOW � 24" (0.6m) o� r �°°�� `' `�'^ o �Oo� ?�oe, ,/ o �'J, /�i/ �/ / ��Oo� �� O �°-�-. �/�/�/ ' �°O e ;��a G��-�:�� /��// , / � � ��'- �'a. // /\ /��\�\��\�\j\�\/��i\\�/\\\\� �` '�;'..:;.,. �,�//�//�,,�\ \ �' — 8'(2.4m) – Spacing Between Check Dams � 'L'=the distance such that points'A'and 'B'are of equal elevation. 'L' % �' �:o�°gy',° —POINT'A' POINT'B' %:�/,�, �� - - �� A��A��A�VA VA \ \ o � oa , `;�i/ji/j�//��/,�/ �/ �/ / �� °��;_,..:. �`��\��\��\��\��\� \� \ \ " s�° `��:-�=�:, \��\��%�%\��%\�%��\�%��%��\��/ �/ / / \,�A��A��j��j�� NOT TO SCALE Figure 4.2.7—Rock Check Dam � Y'olurne II— Constr-uctiort Stor7nwater Pollution Preverttion -August 2012 4-76 Standards accumulation during and after each runoff producing rainfall. Sediment shall be removed when it reaches one half the height of the dam. • Anticipate submergence and deposition above the triangular silt dam and erosion from high flows around the edges of the dam. Immediately repair any damage or any undercutting of the dam. BMP C209: Outlet Protection Purpose Outlet protection prevents scour at conveyance outlets and minimizes the potential for downstream erosion by reducing the velocity of concentrated stormwater flows. Conditions of use Outlet protection is required at the outlets of all ponds, pipes, ditches, or � other conveyances, and where runoff is conveyed to a natural or manmade j drainage feature such as a stream, wetland, lake, or ditch. ' Design and The receiving channel at the outlet of a culvert shall be protected from I Installation erosion by rock lining a minimum of 6 feet downstream and extending up Speeifrcations the channel sides a minimum of 1—foot above the maximum tailwater elevation or 1-foot above the crown, whichever is higher. For large pipes (more than 18 inches in diameter), the outlet protection lining of the channel is lengthened to four times the diameter of the culvert. • Standard wingwalls, and tapered outlets and paved channels should also be considered when appropriate for permanent culvert outlet protection. (See WSDOT Hydraulic Manual, available through WSDOT Engineering Publications). • Organic or synthetic erosion blankets, with or without vegetation, are usually more effective than rock, cheaper, and easier to install. Materials can be chosen using manufacturer product specifications. ASTM test results are available for most products and the designer can choose the correct material for the expected flow. • With low flows, vegetation(including sod) can be effective. • The following guidelines shall be used for riprap outlet protection: 1. If the discharge velocity at the outlet is less than 5 fps (pipe slope less than 1 percent), use 2-inch to 8-inch riprap. Minimum thickness is 1-foot. 2. For 5 to 10 fps discharge velocity at the outlet (pipe slope less than 3 percent), use 24-inch to 48-inch riprap. Minimum thickness is 2 feet. I 3. For outlets at the base of steep slope pipes (pipe slope greater than 10 percent), an engineered energy dissipater shall be used. ', • Filter fabric or erosion control blankets should always be used under I riprap to prevent scour and channel erosion. G'olume II— Construction Stormwater Pollution Prevention-August 2012 � 4-78 • New pipe outfalls can provide an opportunity for low-cost fish habitat improvements. For example, an alcove of low-velocity water can be created by constructing the pipe outfall and associated energy dissipater back from the stream edge and digging a channel, over- widened to the upstream side, from the outfall. Overwintering juvenile and migrating adult salmonids may use the alcove as shelter during high flows. Bank stabilization, bioengineering, and habitat features may be required for disturbed areas. This work may require a HPA. See Volume V for more information on outfall system design. Maintena��ce . Inspect and repair as needed. Sta�zdards . Add rock as needed to maintain the intended function. • Clean energy dissipater if sediment builds up. I Volume II—Construction Stonnwater Polla�tion Preveratiora -August 2012 4-79 BMP C232: Gravel Filter Berm Purpose A gravel filter berm is constructed on rights-of-way or traffic areas within a construction site to retain sediment by using a filter berm of gravel or crushed rock. Conditions of Use Where a temporary measure is needed to retain sediment from rights-of- way or in traffic areas on construction sites. Design and • Berm material shall be 3/4 to 3 inches in size, washed well-grade gravel Installation or crushed rock with less than 5 percent fines. Specifications Spacing of berms: . — Every 300 feet on slopes less than 5 percent — Every 200 feet on slopes between 5 percent and 10 percent — Every 100 feet on slopes greater than 10 percent • Berm dimensions: — 1 foot high with 3H:1 V side slopes — 8linear feet per 1 cfs runoff based on the 10-year, 24-hour design storm Maintenance • Regular inspection is required. Sediment shall be removed and filter Standards material replaced as needed. BMP C233: Silt Fence Purpose Use of a silt fence reduces the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoffvelocities of overland flow. See Figure 4.2.12 for details on silt fence construction. Conditions of Use Silt fence may be used downslope of all disturbed areas. • Silt fence shall prevent soil carried by runoff water from going ' beneath, through, or over the top of the silt fence, but shall allow the ', water to pass through the fence. ', • Silt fence is not intended to treat concentrated flows, nar is it intended !� to treat substantial amounts of overland flow. Convey any I, concentrated flows through the drainage system to a sediment pond. �, • Do not construct silt fences in streams or use in V-shaped ditches. Silt �� fences do not provide an adequate method of silt control for anything 'I deeper than sheet or overland flow. Volurne II—Construction Stormwater Polltitiori Prel�e�ition -August 2012 4-8d' Joints in (ilter fabric shall be spl�ced at posts. Use staples. wire rings or 2'x2"by 14 Ga. wire or equivalent to attach fabric to posts equivalent. �f standard - , strength fabric used 1._ j I F�Iter fabr�c � c N _� C � 6' max �— _ Minimum 4"x4"trench � � — ' N � Backfill trench wifh native so�f � �� Post spac�ng may be increased or 3`4"-1.5"washed gravel to 8' if wire backing is used 2"x2"wood posts.steel fence posts.or equivalent Figure 4.2.12—Silt Fence Design and • Use in combination with sediment basins or other BMPs. Installation Maximum slope steepness (normal (perpendicular) to fence line) Specifications � 1 H:1 V. • Maximum sheet or overland flow path length to the fence of 100 feet. • Do not allow flows greater than 0.5 cfs. • The geotextile used shall meet the following standards. All geotextile properties listed below are minimum average roll values (i.e., the test result for any sampled roll in a lot shall meet or exceed the values shown in Table 4.2.3): Table 4.2.3 Geotextile Standards Polymeric Mesh AOS 0.60 mm maximum for slit film woven(#30 sieve).030 (ASTM D4751) mm maximum for all other geotextile types(#50 sieve). 0.15 mm minimum for all fabric types(#100 sieve). Water Permittivity 0.02 sec'minimum (ASTM D4491) �� Grab Tensile Strength 180 lbs.Minimum for extra strength fabric. (ASTM D4632) 100 lbs minimum for standard strength fabric. Grab Tensile Strength 30%maximum (ASTM D4632) Ultraviolet Resistance 70%minimum (ASTM D4355) • Support standard strength fabrics with wire mesh, chicken wire, 2-inch x 2-inch wire, safety fence, or jute mesh to increase the strength of the Volume II—Construction Stormwater Pollution Prevention -August 2012 4-89 fabric. Silt fence materials are available that have synthetic mesh __� backing attached. • Filter fabric material shall contain ultraviolet ray inhibitors and stabilizers to provide a minimum of six months of expected usable construction life at a temperature range of 0°F. to 120°F. • One-hundred percent biodegradable silt fence is available that is strong, long lasting, and can be left in place after the project is completed, if permitted by local regulations. • Refer to Fi�ure 4.2.12 for standard silt fence details. Include the following standard Notes for silt fence on construction plans and specifications: 1. The contractor shall install and maintain temporary silt fences at the locations shown in the Plans. 2. Construct silt fences in areas of clearing, grading, or drainage prior to starting those activities. I, 3. The silt fence shall have a 2-feet min. and a 2%z-feet max. height above the original ground surface. 4. The filter fabric shall be sewn together at the point of manufacture to form filter fabric lengths as required. Locate all sewn seams at � support posts. Alternatively, two sections of silt fence can be 'i overlapped, provided the Contractor can demonstrate, to the � satisfaction of the Engineer, that the overlap is long enough and that the adjacent fence sections are close enough together to prevent silt laden water from escaping through the fence at the overlap. ' 5. Attach the filter fabric on the up-slope side of the posts and secure ', with staples,wire, or in accordance with the manufacturer's ' recommendations. Attach the filter fabric to the posts in a manner ! that reduces the potential for tearing. 6. Support the filter fabric with wire or plastic mesh, dependent on the properties of the geotextile selected for use. If wire or plastic mesh is used, fasten the mesh securely to the up-slope side of the posts with the filter fabric up-slope of the mesh. 7. Mesh support, if used, shall consist of steel wire with a maximum mesh spacing of 2-inches, or a prefabricated polymeric mesh. The strength of the wire or polymeric mesh shall be equivalent to or greater than 1801bs. grab tensile strength. The polymeric mesh must be as resistant to the same level of ultraviolet radiation as the filter fabric it supports. ', 8. Bury the bottom of the filter fabric 4-inches min. below the ground '' surface. Backfill and tamp soil in place over the buried portion of the filter fabric, so that no flow can pass beneath the fence and ' Volume II— Cortstruction Stonnwater Pollution Preventio�r -Augt.rst 2012 I 4-90 scouring cannot occur. When wire or polymeric back-up support mesh is used, the wire or polymeric mesh shall extend into the �_,. ground 3-inches min. 9. Drive or place the fence posts into the ground 18-inches min. A 12—inch min. depth is allowed if topsoil or other soft subgrade soil is not present and 18-inches cannot be reached. Increase fence post min. depths by 6 inches if the fence is located on slopes of 3H:1 V or steeper and the slope is perpendicular to the fence. If required post depths cannot be obtained, the posts shall be adequately secured by bracing or guying to prevent overturning of the fence due to sediment loading. 10. Use wood, steel or equivalent posts. The spacing of the supporl posts shall be a maximum of 6-feet. Posts shall consist of either: ' • Wood with dimensions of 2-inches by 2-inches wide min. and , a 3-feet min. length. Wood posts shall be free of defects such I as knots, splits, or gouges. � No. 6 steel rebar or larger. • ASTM A 120 steel pipe with a minimum diameter of 1-inch. • U, T, L, or C shape steel posts with a minimum weight of 1.35 lbs./ft. • Other steel posts having equivalent strength and bending resistance to the post sizes listed above. 11. Locate silt fences on contour as much as possible, except at the ends of the fence, where the fence shall be turned uphill such that the silt fence captures the runoff water and prevents water from flowing around the end of the fence. 12. If the fence must cross contours, with the exception of the ends of the fence, place gravel check dams perpendicular to the back of the fence to minimize concentrated flow and erosion. The slope of the fence line where contours must be crossed shall not be steeper than 3H:1V. • Gravel check dams shall be approximately 1-foot deep at the back of the fence. Gravel check dams shall be continued perpendicular to the fence at the same elevation until the top of the check dam intercepts the ground surface behind the fence. � Gravel check dams shall consist of crushed surfacing base course, gravel backfill for walls, or shoulder ballast. Gravel check dams shall be located every 10 feet along the fence where the fence must cross contours. • Refer to Fi�ure 4.2.l3 for slicing method details. Silt fence installation using the slicing method specifications: Volume II—Construction Stormwater Pollartzon Prevention -August 2012 4-91 1. The base of both end posts must be at least 2- to 4-inches above the top of the filter fabric on the middle posts for ditch checks to drain properly. Use a hand level or string level, if necessary, to mark base points before installation. 2. Install posts 3- to 4-feet apart in critical retention areas and 6- to 7- feet apart in standard applications. 3. Install posts 24-inches deep on the downstream side of the silt fence, and as close as possible to the filter fabric, enabling posts to I support the filter fabric from upstream water pressure. ��I 4. Install posts with the nipples facing away from the filter fabric. �� 5. Attach the filter fabric to each post with three ties, all spaced within the top 8-inches of the filter fabric. Attach each tie 'i diagonally 45 degrees through the filter fabric, with each puncture �I, at least 1-inch vertically apart. Each tie should be positioned to �I hang on a post nipple when tightening to prevent sagging. �, 6. Wrap approximately 6-inches of fabric around the end posts and ', secure with 3 ties. ' 7. No more than 24-inches of a 36-inch filter fabric is allowed above ' ground level. Compact the soil immediately next to the filter fabric with the front , wheel of the tractor, skid steer, or roller exerting at least 60 pounds per square inch. Compact the upstream side first and then each side twice for a total of four trips. Check and correct the silt fence installation for any deviation before compaction. Use a flat-bladed shovel to tuck fabric deeper into the ground if necessary. �I I � 'I �! I 'I Volume II—Construction Stormwater Pollution Prevention -August 2012 4-92 ' �onrin'h�yl�t rOST i�AGIMG: �wa�.24' 7's�x.on�rn rvns - . .............. .. ...............Tap d Fab�tc � •'sax.an��o1Ms ar�a� r BpJI AK�ch TaCflc b �qsO�rw sN��f ys�t �8' F LOw--- oNw.wr.aeh.��.ar : �OST DE�TM: sNt 1�nc�2 Eo 4 tlrMs � ��h Y�I�w�f�Yl�d I wAtl�NNe��a�NM i aa hbflc�w�f�Ynd 60 psJ.er��l�r { i' dsya�al aGeclr+�nR t00%cowp�cq 100%con��ctlo� �s��h. � .��.. �...�.... %\\�%\%/\\f �\%�\\/�\/�\ / / / / // /� / • �:- \ /��%��j�%S ��\��\��\� �,I_,,, ,,, / / / /�/�/�//�� \//\�/��`�� ATIACFi�lf OE�MS: //��/\��f � //\\/��\�� •Getlwr faMc at po�s.�newed. //\��j/�j/�� \//\�/��/��j�\ •uY�xe tree nes per pmb a�w�n�n mp s•w tsbk. �\�j\��\� " \�\�/\��\� •Po�Mfon sadi tN di�goneNy.p�na��rg hdes varocary ��/ % �/ �/ � �/%�// % a�n�n d Y apeA. �\\��\ �\ • \\�\�\�\ •Hanq aeen tla m s pon NppM and tly1M�n secudy. No more lhan 24'of a 36'fabric u»c.c�ue�Isao�l a�soR.+re- is allowed above grou�d. Rd ot sit Ience ♦— Op�raoo^ � Pbst krnaled • aller compacuon fet�ic O '0OY' SIt Fence � l� . --�-f--- �--;-,-,� 1�.,�... �,� ��O•�'� �,�.� �:��y1`�. .��;o,% '��► � fC� ��'Y�`��f�� 'i..� � ��% �i;i:� �� 1 � � � . $ ` `fii ��j��.t;iy,\i�l'i � 2�-�RIfTI ��:�� \��. ��`f��j��j��j� , ,.�' � i i �i ii i.�♦ O � � Y� � �, � ;i ��.��/'l/ �� i:!;�i�i•. �i�i�� ' r i , \�� v\ 'C\��\\� ..�\ \ ��., C �\ Haimoned chbel poim Stcing o�ade (�6►rm wk�� (18 mm widM�) Complatod kntala�Von Hitxatory plow is not acceptable because of haimntal compacdon Figure 4.2.13—Silt Fence Installation by Slicing Method Maintenance • Repair any damage immediately. Standards Intercept and convey all evident concentrated flows uphill of the silt • fence to a sediment pond. • Check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow and then causing channelization of flows parallel to the fence. If this occurs,replace the fence or remove the trapped sediment. I II Volume II—Construction Stormwater Pollution Prevention -August 2012 4-93 • Remove sediment deposits when the deposit reaches approximately one-third the height of the silt fence,or install a second silt fence. • Replace filter fabric that has deteriorated due to tiltraviolet breakdo��n. BMP C234: Vegetated Strip Purpose Vegetated strips reduce the transport of coarse sediment from a construction site by providing a temporary physical ban-ier to sedirnent and reducing the runoff velocities of overland flow. Conditions of Use • Vegetated strips may be used downslope of all disturbed areas. • Vegetated strips are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment pond. The only circumstance in which overland flow can be treated solely by a strip, rather than by a sediment pond, is when the following criteria are met (see Table 4.2.4): Table 4.2.4 Contributing Drainage Area for Vegetated Strips Average Contributing Average Contributing area Max Contributing area Slo e Percent Slo e area Flo�v ath Len th 1.SH:1 V or flatter 67%or flatter 100 feet 2H:1 V or flatter 50%or flatter 115 feet 4H:1 V or flatter 25%or flatter 150 feet 6H:1 V or flatter 16.7%or flatter 200 feet I OH:1 V or flatter 10%or flatter 250 feet Design and • The vegetated strip shall consist of a minimum of a 25-foot flowpath Installation length continuous strip of dense vegetation with topsoil. Grass- Specifications covered, landscaped areas are generally not adequate because the volume of sediment overwhelms the grass. Ideally, vegetated strips shall consist of undisturbed native growth with a well-developed soil that allows for infiltration of runoff. • The slope within the strip shall not exceed 4H:1 V. • The uphill boundary of the ��egetated strip shall be delineated with clearing limits. Maintenance • Any areas damaged by erosion or construction activity shall be Standards seeded immediately and protected by mulch. • If more than 5 feet of the original vegetated strip width has had vegetation removed or is being eroded, sod must be installed. • If there are indications that concentrated flows are traveling across the buffer, surface water controls must be installed to reduce the flows i�olurne 11—Construction Stormwater Pollutiort Prevention -Aisgust 2012 4-94 entering the buffer, or additional perimeter protection must be installed. BMP C235: Wattles Purpose Wattles are temporary erosion and sediment control barriers consisting of straw, compost, or other material that is wrapped in biodegradable tubular plastic or similar encasing material. They reduce the velocity and can spread the flow of rill and sheet runoff, and can capture and retain sediment. Wattles are typically 8 to ]0 inches in diameter and 25 to 30 feet in length. Wattles are placed in shallow trenches and staked along the contour of disturbed or newly constructed slopes. See Fi�ure 4.2.14 for typical construction details. WSDOT Standard Plan I-3030-00 also provides information on Wattles (http://www.wsdot.wa.gov/Design/Standards/Plans.htm#Sectionl) COitl�lll0ilS Oj L'se • Use wattles: • In disturbed areas that require immediate erosion protection. • On exposed soils during the period of short construction delays, or over winter months. • On slopes requiring stabilization until permanent vegetation can be established. • The material used dictates the effectiveness period of the wattle. Generally, Wattles are typically effective for one to two seasons. • Prevent rilling beneath wattles by properly entrenching and abutting wattles together to prevent water from passing between them. Desig�r Criteria • Install wattles perpendicular to the flow direction and parallel to the slope contour. • Narrow trenches should be dug across the slope on contour to a depth of 3- to 5-inches on clay soils and soils with gradual slopes. On loose soils, steep slopes, and areas with high rainfall, the trenches should be dug to a depth of 5-to 7- inches, or 1/2 to 2/3 of the thickness of the wattle. • Start building trenches and installing wattles from the base of the slope and work up. Spread excavated material evenly along the uphill slope and compacted using hand tamping or other methods. • Construct trenches at intervals of 10- to 25-feet depending on the steepness of the slope, soil type, and rainfall. The steeper the slope the closer together the trenches. • Install the wattles snugly into the trenches and abut tightly end to end. Do not overlap the ends. • Install stakes at each end of the wattle, and at 4-foot centers along entire length of wattle. i'ohrme II— Construction Stor•mtivater Pollution Prevention -August 2012 4-95 • If required, install pilot holes for the stakes using a straight bar to drive holes through the wattle and into the soil. • Wooden stakes should be approximately 3i'4 x 3r'4 x 24 inches min. Willow cuttings or 3/8-inch rebar can also be used for stakes. • Stakes should be driven through the middle of the wattle, leaving 2 to 3 inches of the stake protruding above the wattle. Maintenance • Wattles may require maintenance to ensure they are in contact �vith Standards soil and thoroughly entrenched, especially after significant rainfall on steep sandy soils. Volume II— Construction Stonnwater Pollution Preve��trofr -Augarst 2012 4-96 3'�' —�I �� , (1.2m) ,��, � �' � �� , l ;` , � . � �. Straw Rolls Must ';', ' ' � �- �� y�1' ,,;;' '� `\. Be Placed Along :,�� y�: �� ii% Slope Contours � u., , �` ti '- ;%;� ; �'� Adjacent rolls shall ;�'�' � ti� tighty abut�1 ;�;;' � � �� s -� � �;� ; �J� � . \ ,J ,t �, �ii , �W" / ;� ��.. ,,, „ � �� `�>'�� \Y � 10'-25'(3-8m) �/1 ,�\��\� % �� ,j�/ � ��, '.i�� j?,� ;�� „ ��, Spacing Depends /� � on Soll Type and Y ,/��i��,�\ SedimeM,organic matter, Slope Steepness . \� and native seeds are �captured behind me rolls. � `\;//\ � ' ��\,. , ,- -�---�1 �---�. ; � 3'-5'(75-125mm) %� ��,� � � �/�\� 8"-10"DIA. ;:;� . _y ��/� ,\ (200-250mm) , .. � ��j / � i,f� ,,,� - Live Stake T- ��, Y \\ _- .. , //r_ �� ' � � � 1" X 1" Stake ';'11� not to sCale (25 x 25mm) �� NOTE: 1.Straw roll installation requires the placement and secut�e staking of the toll in a trench,3"-5"(75-125mm) deep,dug on contour, runoff must not be allowed to run under or azound roll. Figure 4.2.14—Wattles Vol:�me II— Co�kstruction Stormwater Pollution Preventiori -August 2012 4-97 • Inspect the slope after significant storms and repair any areas ��-here wattles are not tightly abutted or water has scoured beneath the wattles. Approved as Ecology has approved products as able to meet the requirements of BMP Equivalent C235. The products did not pass through the Technology Assessment Protocol —Ecology (TAPE)process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at http:i/www.ecy.wa.�programs/wq/storm�vater/newtech/equivalent.html BMP C236: Vegetative Filtration Purpose Vegetative Filtration may be used in conjt►nction with F3MP C241 Temporary Sediment Ponds, BMP C206 Level Spreader and a pumping system with surface intake to improve turbidity levels of stormwater discharges by filtering through existing vegetation where undisturbed forest floor duff layer or established lawn with thatch layer are present. Vegetative Filtration can also be used to infiltrate dewatering waste from foundations, vaults, and trenches as long as runoff does not occur. Conditions of Use • For every five acre of disturbed soil use one acre of grass field, farm pasture, or wooded area. Reduce or increase this area depending on project size, ground water table height, and other site conditions. • Wetlands shall not be used for filtration. • Do not use this BMP in areas with a high ground water table, or in areas that will have a high seasonal ground «�ater table during the use of this BMP. • This BMP may be less effective on soils that prevent the infiltration of the water, such as hard till. • Using other effective source control measures throughout a construction site will prevent the generation of additional highly turbid water and may reduce the time period or area need for this BMP. • Stop distributing water into the vegetated area if standing water or erosion results. Design Criteria • Find land adjacent to the project that has a vegetated field, preferably a farm field, or wooded area. • If the project site does not contain enough vegetated field area consider obtaining permission from adjacent lando�vners (especially for farm fields). • Install a pump and downstream distribution manifold depending on the project size. Generally, the main distribution line should reach 100 to 200-feet long (many large projects, or projects on tight soil, will Volume II—Construction Stormwater Pollution Prevention -August 2012 4-98 BMP C240: Sediment Trap Purpose A sediment trap is a small temporary ponding area with a gravel outlet used to collect and store sediment from sites cleared and/or graded during construction. Sediment traps, along with other perimeter controls, shall be installed before any land disturbance takes place in the drainage area. Co�:ditions of Use Prior to leaving a construction site, stormwater runoff must pass through a sediment pond or trap or other appropriate sediment removal best management practice. Non-engineered sediment traps may be used on-site prior to an engineered sediment trap or sediment pond to provide additional sediment removal capacity. It is intended for use on sites where the tributary drainage area is less than 3 acres, with no unusual drainage features, and a projected build-out time of six months or less. The sediment trap is a temporary measure (with a design life of approximately 6 months) and shall be maintained until the site area is permanently protected against erosion by vegetation and/or structures. Sediment traps and ponds are only effective in removing sediment down to about the medium silt size fraction. Runoff with sediment of finer grades (fine silt and clay)will pass through untreated, emphasizing the need to control erosion to the maximum extent first. Whenever possible, sediment-laden water shall be discharged into on-site, relatively level, vegetated areas (see BMP C234—Vegetated Stri�). This is the only way to effectively remove fine particles from runoff unless chemical treatment or filtration is used. This can be particularly useful after initial treatment in a sediment trap or pond. The areas of release must be evaluated on a site-by-site basis in order to determine appropriate locations for and methods of releasing runoff. Vegetated wetlands shall not be used for this purpose. Frequently, it may be possible to pump water from the collection point at the downhill end of the site to an upslope vegetated area. Pumping shall only augment the treatment system, not replace it, because of the possibility of pump failure or runoff volume in excess of pump capacity. All projects that are constructing permanent facilities for runoff quantity control should use the rough-graded or final-graded permanent facilities for traps and ponds. This includes combined facilities and infiltration facilities. When permanent facilities are used as temporary sedimentation facilities, the surface area requirement of a sediment trap or pond must be met. If the surface area requirements are larger than the surface area of the permanent facility, then the trap or pond shall be enlarged to comply with the surface area requirement. The permanent pond shall also be divided into two cells as required for sediment ponds. Volume II—Construction Stormwater Pollution Prevention -August 2012 4-101 Either a permanent control structure or the temporary control structure (described in BMP C241, Temporary Sediment Pond) can be used. If a permanent control structure is used, it may be advisable to partially restrict '�, the lower orifice with gravel to increase residence time while still allowing ' dewatering of the pond. A shut-off valve may be added to the control , structure to allow complete retention of stormwater in emergency situations. In this case, an emergency overflow weir must be added. A skimmer may be used for the sediment trap outlet if approved by the Local Permitting Authority. Design and • See Fi�ures 4.2.16 and 4.2.17 for details. Installation . If permanent runoff control facilities are part of the project, they Specifications should be used for sediment retention. • To determine the sediment trap geometry, first calculate the design surface area (SA) of the trap, measured at the invert of the weir. Use the following equation: SA = FS(Q�/VS) where QZ = Design inflow based on the peak discharge from the developed 2-year runoff event from the contributing drainage area as computed in the hydrologic analysis. The , 10-year peak flow shall be used if the project size, expected li timing and duration of construction, or downstream '�, conditions warrant a higher level of protection. If no �i hydrologic analysis is reyuired, the Rational Method may I, be used. ! VS = The settling velocity of the soil particle of interest. The ' 0.02 mm (medium silt) particle with an assumed density of �, 2.65 g/cm3 has been selected as the particle of interest and has a settling velocity(VS) of 0.00096 ft/sec. FS = A safety factor of 2 to account for non-ideal settling. , Therefore, the equation for computing surface area becomes: SA = 2 x QZ/0.00096 or 2080 square feet per cfs of inflow Note: Even if permanent facilities are used, they must still have a surface area that is at least as large as that derived from the above formula. If they do not, the pond must be enlarged. • To aid in determining sediment depth, all sediment traps shall have a staff gauge with a prominent mark ]-foot above the bottom of the trap. Volume II—Construction Stormwater Pollution Prevention -August 2012 4-102 • Sediment traps may not be feasible on utility projects due to the limited work space or the short-term nature of the work. Portable tanks may be used in place of sediment traps for utility projects. Maintenance • Sediment shall be removed from the trap when it reaches 1-foot in Standards depth. • Any damage to the pond embankments or slopes shall be repaired. Surface area determined 4�f� Min � at top of weir � �� — — — — — — — — — — — — � �� \. 1' Min. Overflow � 1'Min. � '��y ••.� 1' Min. �� 3.5'-5' ., . ',, � d� 1.5'Min. `', , Flat Bottom RipRap '/.'-1.5", 2"-4'Rock Washed gravel Note:Trap may be formed by berm or by Geotextile / partial or complete excavation Discharge to stabilized conveyance, outlet, or level spreader Figure 4.2.16-Cross Section of Sediment Trap � 6' Min. - _ ' I I-i � I i I=i i—I I 1;, 1' Min. depth overflow spillway ��I-1 I I=1 I I I _ I ii—�i�—i i i---�i—I_I— � o �I I I— ' =i— i—i i i—i i - I I'� - �' _ Native soil or � I�i . �+��_� Min. 1'depth compacted backfill � � ' • ' —I I - 2"-4"' rock Geotextile -I'�- i —.I._� '- ''-I I'— � —I I I=I I I-' Min. 1'depth 3/4"-1.5" - �1- I - I I-"1=!� —i I 1-1 '-1 I 1-1 washed gravel Figure 4.2.17-Sediment Trap Outlet Voh�nae II-Co�asti-csction Stonnx�ater Pollution Preveiitiorz -August 2012 4-103 BMP C241: Temporary Sediment Pond Purpose Sediment ponds remove sediment from runoff originating from disturbed areas of the site. Sediment ponds are typically designed to remove sediment no smaller than medium silt (0.02 mm). Consequently, they usually reduce turbidity only slightly. Conditions of Use Prior to leaving a construction site, stormwater runoff must pass through a sediment pond or other appropriate sediment removal best management practice. A sediment pond shall be used where the contributing drainage area is 3 acres or more. Ponds must be used in conjunction with erosion control practices to reduce the amount of sediment flowing into the basin. Design and • Sediment basins must be installed only on sites where failure of the Installation structure would not result in loss of life, damage to homes or Specifications buildings, or interruption of use or service of public roads or utilities. Also, sediment traps and ponds are attractive to children and can be very dangerous. Compliance with local ordinances regarding health and safety must be addressed. If fencing of the pond is required, the type of fence and its location shall be shown on the ESC plan. • Structures having a maximum storage capacity at the top of the dam of 10 acre-ft(435,600 ft3) or more are subject to the Washington Dam Safety Regulations (Chapter 173-175 WAC). • See Figures 4.2.18, 4.2.19, and 4.2.20 for details. • If permanent runoff control facilities are part of the project, they '� should be used for sediment retention. The surface area requirements jof the sediment basin must be met. This may require temporarily enlarging the permanent basin to comply with the surface area I� requirements. The permanent control structure must be temporarily I replaced with a control structure that only allows water to leave the I pond from the surface or by pumping. The permanent control structure I' must be installed after the site is fully stabilized. . � • Use of infiltration facilities for sedimentation basins during 'i construction tends to clog the soils and reduce their capacity to ''� infiltrate. If infiltration facilities are to be used, the sides and bottom of the facility must only be rough excavated to a minimum of 2 feet above final grade. Final grading of the infiltration facility shall occur only when all contributing drainage areas are fully stabilized. The jinfiltration pretreatment facility should be fully constructed and used with the sedimentation basin to help prevent clogging. • Determining Pond Geometry Obtain the discharge from the hydrologic calculations of the peak flo�� , li for the 2- ear runoff event . The 10- ear eak flow sh 11 � y (Qz) y p a be used if , Volume II—Construction Stormwater Pollution Prevention -August 2012 �� I 4-104 the project size, expected timing and duration of construction, or downstream conditions warrant a higher level of protection. If no hydrologic analysis is required, the Rational Method may be used. Determine the required surface area at the top of the riser pipe with the equation: SA = 2 x Q2/0.00096 or 2080 square feet per cfs of inflow See BMP C240 for more information on the derivation of the surface area calculation. The basic geometry of the pond can now be determined using the following design criteria: • Required surface area SA (from Step 2 above) at top of riser. • Minimum 3.5-foot depth from top of riser to bottom of pond. • Maximum 3H:1 V interior side slopes and maximum 2H:1 V exterior slopes. The interior slopes can be increased to a maximum of 2H:1 V if fencing is provided at or above the maximum water surface. • One foot of freeboard between the top of the riser and the crest of the emergency spillway. • Flat bottom. • Minimum 1-foot deep spillway. • Length-to-width ratio between 3:1 and 6:1. • Sizing of Discharge Mechanisms. The outlet for the basin consists of a combination of principal and emergency spillways. These outlets must pass the peak runoff expected from the contributing drainage area for a 100-year storm. If, due to site conditions and basin geometry, a separate emergency spill- way is not feasible, the principal spillway must pass the entire peak runoff expected from the 100-year storm. However, an attempt to provide a separate emergency spillway should always be made. The runoff calculations should be based on the site conditions during construction. The flow through the dewatering orifice cannot be utilized when calculating the 100-year storm elevation because of its potential to become clogged; therefore, available spillway storage must begin at the principal spillway riser crest. The principal spillway designed by the procedures contained in this standard will result in some reduction in the peak rate of runoff. However, the riser outlet design will not adequately control the basin discharge to the predevelopment discharge limitations as stated in Minimum Requirement#7: Flow Control. However, if the basin for a permanent stormwater detention pond is used for a temporary Volume II—Construction Stonnwater Pollution Prevention -August 2012 4-105 sedimentation basin, the control structure for the permanent pond can ��, be used to maintain predevelopment discharge limitations. The size of the basin, the expected life of the construction project, the anticipated downstream effects and the anticipated weather conditions during construction, should be considered to determine the need of additional discharge control. See Fi�ure 4.2.21 for riser inflow curves. Key divider into slope �-- - to prevent flow around sides The pond length shall be 3 to 6 times the maximum pond width Emergency overFlow � spillwa i � i ! 1 � � ' _ —Pon length �serp r` , Infbw- ' -- �' Silt fence or -�'� ! Discharge to stabilized �quivalentdivider `b � � conveyance,outlet,or � i -*---�__ � level spreader \� 'b ��+I� �'� � � �;, ;.\ // �� . Note:Pond may be formed by berm w ` � by partial or complete excavation y /y� �./ Figure 4.2.18—Sediment Pond Plan View il II Riser pipe (principal spillway) Crest of open at top with emergenc spillway 6'min.Width trash rack -i=T � ,�,,,N Embankment compacted 95% ' '�' Dewatering device � ,• ___ --_� ervious materials such as �'� �' "s (see riser detail) \ �—_ _-- _ -__ gravel or clean sand shall _� ' 2 ~_ ��=-'-=-"--- - not be used � -:--._------ 'i �—�� - "'5=-------=-�_-�_---_-_ s _:�� - __-___ ----"_-�_-_---_- '` �� -�=i I I' L-I I! .I I �-1 I�i� I � �I��''� u�i �Ti-1�I- I=1 � r- I IJ I f ` L I—I==i I I � i I-1 I 1-1':! ''�I.;I_ ' I I, I�' - I i�kT�I i�� 1=I� � Discharge to stabilized Wire-backed silt fence Dewatering Concrete base conve ance outlet or with ftl er fabn!cs�wrapped orifice (see riser detail) level preader equivalent divider Figure 4.2.19—Sediment Pond Cross Section Volume II—Cortstj-uctiort Stor�ntivater Pollution Prevention -August 2012 4-106 Polyethylene cap Provide adequate straPa�9 Perforated potyethylene _ drainage tubing,diameter - Cortugated min.2'larger than melal riser dewatering orifice. - 3.5"min. Tubing shall comply : WaleNght Dewatem orifice,schedule, with ASTM F667 and = �upling Tack weld 40 steel stub min. AASHTO M294 - ' Diame[er as per calculations %i�,�iii i 6"min. r--- L"_ "'� 18'min. i Altematively,metal stakes L Conc rete base and wi2 may be used to prevent flohation �2X riser dia.Min.—� Figure 4.2.20—Sediment Pond Riser Detail Volume II—Constnsction Stonnwater Pollution Prevention -August 2012 4-107 100 ' i 72 54 48 I 42 � � � � i � � 36 � 33 � � � � so i I � � � �� i � ; I � ! � ' ; 2� I� � i c ° ! 18 � � w ! ( ! � t 0 n � o �� ' 15 w � � � — i , i � � � � p � I 12 � � � . ' � ; , ; ' i 10 i 1 � I I i I , 1 � I � � � HEAD IN FEET (measu�red from crest of riser) �� Q =9.739 DH3�= ..�. x �n dorit�ca=3.782 D H Q in efs, D and H in f�et Siope chang� oeeurs at weir-orifiee transition I I Figure 4.2.21 — Riser Inflow Curves volume II—Construction Stormwater Pollution Prevention -August 2012 4-108 Principal Spillway: Determine the required diameter for the principal spillway (riser pipe). The diameter shall be the minimum necessary to pass the site's 15-minute, 10-year flowrate. If using the Western Washington Hydrology Model (WW F�M), Version 2 or 3, design flow is the 10-year(1 hour) flow for the developed (unmitigated) site, multiplied by a factor of 1.6. Use Figure 4.2.21 to determine this diameter(h = l-foot). Note: A permanent control structure may be used rnstead of a temporary risef-. Emergency Overflow Spillway: Determine the required size and design of the emergency overflow spillway for the developed l 00-year peak flow using the method contained in Volume III. Dewatering Orifice: Determine the size of the dewatering orifice(s) (minimum 1-inch diameter) using a modified version of the discharge equation for a vertical orifice and a basic equation for the area of a circular orifice. Determine the required area of the orifice with the following equation: A — AS�2h�o.s ° 0.6x3600Tg os where Ao = orifice area(square feet) AS = pond surface area(square feet) h = head of water above orifice (height of riser in feet) T = dewatering time (24 hours) g = acceleration of gravity (32.2 feet/secondZ) Convert the required surface area to the required diameter p of the orifice: � D= 24x A° =13.54x Ao � The vertical, perforated tubing connected to the dewatering orifice must be at least 2 inches larger in diameter than the orifice to improve flow characteristics. The size and number of perforations in the tubing should be large enough so that the tubing does not restrict flow. The orifice should control the flow rate. • Additional Design Specifications The pond shall be divided into two roughly equal volume cells by a � permeable divider that will reduce turbulence while allowing movement of water beri�veen cells. The divider shall be at least one- �� half the height of the riser and a minimum of one foot below the top of ' the riser. Wire-backed, 2- to 3-foot high, extra strength filter fabric �� supported by treated 4"x4"s can be used as a divider. Alternatively, �� staked straw bales wrapped with filter fabric (geotextile) may be used. i If the pond is more than 6 feet deep, a different mechanism must be proposed. A riprap embankment is one acceptable method of Volume II—Construction Stonnwater Pollution Prevention -August 2012 4-109 separation for deeper ponds. Other designs that satisfy the intent of this provision are allowed as long as the divider is permeable, structurally sound, and designed to prevent erosion under or around the barrier. To aid in determining sediment depth, one-foot intervals shall be prominently marked on the riser. If an embankment of more than 6 feet is proposed, the pond must comply with the criteria contained in Volume IiI regarding dam safety for detention BMPs. • The most common structural failure of sedimentation basins is caused � by piping. Piping refers to two phenomena: (1) water seeping through I fine-grained soil, eroding the soil grain by grain and forming pipes or '� tunnels; and, (2) water under pressure flowing upward through a ' granular soil with a head of sufficient magnitude to cause soil grains to , lose contact and capability for support. The most critical construction sequences to prevent piping will be: ' 1. Tight connections between riser and barrel and other pipe connections. 2. Adequate anchoring of riser. 3. Proper soil compaction of the embankment and riser footing. 4. Proper construction of anti-seep devices. Maintenance • Sediment shall be removed from the pond when it reaches 1—foot in Standards depth. • Any damage to the pond embankments or slopes shall be repaired. BMP C250: Construction Stormwater Chemical Treatment Purpose This BMP applies when using stormwater chemicals in batch treatment or flow-through treatment. Turbidity is difficult to control once fine particles are suspended in stormwater runoff from a construction site. Sedimentation ponds are effective at removing larger particulate matter by gravity settling, but are ineffective at removing smaller particulates such as clay and fine silt. Traditional erosion and sediment control BMPs may not be adequate to ensure compliance with the water quality standards for turbidity in receiving water. Chemical treatment can reliably provide exceptional reductions of turbidity and associated pollutants. Chemical treatment may be required to meet turbidity stormwater discharge requirements, especially when construction is to proceed through the wet season. Conditions of Use Formal written approval from Ecology is required for the use of chemical treatment regardless of site size. The Local Permitting Authority may also Volume II—Construction Stor7nwater Pollution Prevention -August 2012 4-110 Operator Training: Each contractor who intends to use chemical treatment shall be trained by an experienced contractor . Each site using chemical treatment must have an operator trained and certified by an organization approved by Ecology. Standard BMPs: Surface stabilization BMPs should be implemented on site to prevent significant erosion. All sites shall use a truck wheel wash to prevent tracking of sediment off site. Sediment Removal and Disposal: • Sediment shall be removed from the storage or treatment cells as necessary. Typically, sediment removal is required at least once during a wet season and at the decommissioning of the cells. Sediment remaining in the cells between batches may enhance the settling process and reduce the required chemical dosage. • Sediment that is known to be non-toxic may be incorporated into the site away from drainages. BMP C251: Construction Stormwater Filtration Purpose Filtration removes sediment from runoff originating from dishirbed areas of the site. Background Information: Filtration with sand media has been used for over a century to treat water and wastewater. The use of sand filtration for treatment of stormwater has developed recently, generally to treat runoff from streets, parking lots, and residential areas. The application of filtration to con5truction stormwater treatment is currently under development. Conditions of Use Traditional BMPs used to control soil erosion and sediment loss from sites under development may not be adequate to ensure compliance with the water quality standard for turbidity in the receiving water. Filtration may be used in conjunction with gravity settling to remove sediment as small as fine silt (0.5 µm). The reduction in turbidity will be dependent on the particle size distribution of the sediment in the stormwater. In some circumstances, sedimentation and filtration may achieve compliance with the water quality standard for turbidity. The use of construction stormwater filtration does not require approval from Ecology as long as treatment chemicals are not used. Filtration in conjunction with polymer treatment requires testing under the Chemical Technology Assessment Protocol—Ecology (CTAPE)before it can be initiated. Approval from the appropriate regional Ecology office must be obtained at each site where polymers use is proposed prior to use. For more guidance on stormwater chemical treatment see BMP C250. Volume II— Constr-uction Stormwater Pollution Prevention -August 2012 4-I18 Design und Two types of filtration systems may be applied to construction stormwater Installation treatment: rapid and slow. Rapid sand filters are the typical system used Specifications for water and wastewater treatment. They can achieve relatively high hydraulic flow rates, on the order of 2 to 20 gpm/sf, because they have automatic backwash systems to remove accumulated solids. In contrast, slow sand filters have very low hydraulic rates, on the order of 0.02 gpm/sf, because they do not have backwash systems. Slow sand filtration has generally been used to treat stormwater. Slow sand filtration is mechanically simple in comparison to rapid sand filtration but requires a much larger filter area. Filtration Equipment. Sand media filters are available with automatic backwashing features that can filter to 50 µm particle size. Screen or bag filters can filter down to 5 µm. Fiber wound filters can remove particles down to 0.5 µm. Filters should be sequenced from the largest to the smallest pore opening. Sediment removal efficiency will be related to particle size distribution in the stormwater. Treatment Process Description. Stormwater is collected at interception point(s) on the site and is diverted to an untreated stormwater sediment pond or tank for removal of large sediment and storage of the stormwater before it is treated by the filtration system. The untreated stormwater is pumped from the trap, pond, or tank through the filtration system in a rapid sand filtration system. Slow sand filtration systems are designed as flow through systems using gravity. Maintenance Rapid sand filters typically have automatic backwash systems that are Standards triggered by a pre-set pressure drop across the filter. If the backwash water volume is not large or substantially more turbid than the untreated stormwater stored in the holding pond or tank, backwash return to the untreated stortnwater pond or tank may be appropriate. However, other means of treatment and disposal may be necessary. • Screen,bag, and fiber filters must be cleaned and/or replaced when they become clogged. • Sediment shall be removed from the storage and/or treatment ponds as necessary. Typically, sediment removal is required once or twice during a wet season and at the decommissioning of the ponds. Sizing Criteria for Flow-Through Treatment Systems for Flow Control Exempt Water Bodies: When sizing storage ponds or tanks for flow-through systems for flow control exempt water bodies the treatment system capacity should be a factor. The untreated stormwater storage pond or tank should be sized to hold 1.5 times the runoff volume of the 10-year, 24-hour storm event minus the treatment system flowrate for an 8-hour period. For a chitosan- enhanced sand filtration system, the treatment system flowrate should be sized using a hydraulic loading rate between 6-8 gpm/ft2. Other hydraulic Volurrie II— Consri•uction Storrmvater Pollution Preveritiorz -Aasgasst 2012 � 4-119 loading rates may be more appropriate for other systems. Bypass should be provided around the chemical treatment system to accommodate extreme storms. Runoff volume shall be calculated using the methods presented in Volume 3, Chapter 2. Worst-case conditions (i.e., producing the most runof� should be used for analyses (most likely conditions present prior to final landscaping). Sizing Criteria for Flow Control Water Bodies: Sites that must implement flow control for the developed site condition must also control stormwater release rates during construction. Construction site stormwater discharges shall not exceed the discharge durations of the pre-developed condition for the range of pre-developed discharge ratcs from l/2 of the 2-year flow through the 10-year flow as predicted by an approved continuous runoff model. The pre-developed condition to be matched shall be the land cover condition immediately prior to the development project. This restriction on release rates can affect the size of the storage pond, the filtration system, and the flow rate through the filter system. The following is how WWHM can be used to determine the release rates from the filtration systems: 1. Determine the pre-developed flow durations to be matched by entering the land use area under the "Pre-developed" scenario in WWHM. The default flow range is from '/2 of the 2-year flow through the l 0-year flow. 2. Enter the post developed land use area in the "Developed Unmitigated" scenario in WWHM. 3. Copy the land use information from the "Developed Unmitigated" to "Developed Mitigated" scenario. 4. There are two possible ways to model stormwater filtration systems: a. The stormwater filtration system uses an untreated stortnwater storage pond/tank and the discharge from this pond/tank is pumped to one or more filters. In-line filtration chemicals would be added ' to the flow right after the pond/tank and before the filter(s). ', Because the discharge is pumped, WWHM can't generate a ' stage/storage /discharge (SSD)table for this system. This system is ' modeled the same way as described in BMP C250 and is as follows: While in the "Developed Mitigated" scenario, add a pond element under the basin element containing the post-developed land use areas. This pond element represents information on the available untreated stormwater storage and discharge from the filtration system. In cases where the discharge from the filtration system is controlled by a pump, a stage/storage/discharge (SSD)table representing the pond must be generated outside WWHM and Volume II—Constrc�ction Stonnwater Pollution Prevention -August 2012 4-120 imported into WWHM. WWHM can route the runoff from the post-developed condition through this SSD table (the pond) and determine compliance with the flow duration standard. This would be an iterative design procedure where if the initial SSD table proved to be out of compliance, the designer would have to modify the SSD table outside WWHM and re-import in WWHM and route the runoff through it again. The iteration will continue until a pond that enables compliance with the flow duration standard is designed. Notes on SSD table characteristics: • The pump discharge rate would likely be initially set at just below '/2 if the 2-year flow from the pre-developed condition. As runoff coming into the untreated stormwater storage pond increases and the available untreated stormwater storage volume gets used up, it would be necessary to increase the pump discharge rate above %z of the 2-year. The increase(s) above '/2 of the 2-year must be such that they provide some relief to the untreated stormwater storage needs but at the same time they will not cause violations of the flow durarion standard at the higher flows. The final design SSD table will identify the appropriate pumping rates and the corresponding stage and storages. • When building such a flow control system, the design must ensure that any automatic adjustments to the pumping rates will be as a result of changes to the available storage in accordance with the final design SSD table. b. The stormwater filtration system uses a storage pond/tank and the discharge from this pondltank gravity flows to the filter. This is usually a slow sand filter system and it is possible to model it in WWHM as a Filter element or as a combination of Pond and Filter element placed in series. The stage/storage/discharge table(s)may then be generated within WWHM as follows: (i) While in the "Developed Mitigated" scenario, add a Filter element under the basin element containing the post-developed land use areas. The length and width of this filter element would have to be the same as the bottom length and width of the upstream untreated stormwater storage pond/tank. (ii) In cases where the length and width of the filter is not the same as those for the bottom of the upstream untreated stormwater storage tank/pond, the treatment system may be modeled as a Pond element followed by a Filter element. By having these two elements, WWHM would then generate a SSD table for the storage pond which then gravity flows to the Filter element. The Filter element downstream of the untreated storm«-ater Volume II—Construction Stormwater Pollcrtiar Pf-everrtiorr -.9ugust 2012 4-121 storage pond would have a storage component through the media, and an overflow component for when the filtration capacity is exceeded. WWHM can route the runofffrom the post-developed condition through the treatment systems in 4b and determine compliance with the flow duration standard. This would be an iterative design procedure where if the initial sizing estimates for the treatment system proved to be inadequate, the designer would have to modify the system and route the runoff through it again. The iteration would continue until compliance with the flow duration standard is achieved. 5. It should be noted that the above procedures would be used to meet the flow control requirements. The filtration system must be able to meet the runoff treatment requirements. It is likely that the discharge flow rate of '/z of the 2-year or more may exceed the treatment capacity of the system. If that is the case, the untreated stormwater discharge rate(s)(i.e., influent to the treatment system)must be reduced to allow proper treatment. Any reduction in the flows would likely result in the need for a larger untreated stormwater storage volume. If system design does not allow you to discharge at the slower rates as described above and if the site has a retention or detention pond that will serve the planned development, the discharge from the treatment system may be directed to the permanent retention/detention pond to comply with the flow control requirements. ln this case, the untreated stormwater storage pond and treatment system will be sized according to the sizing criteria for flow- through treatment systems for flow control exempt waterbodies described earlier except all discharges (water passing through the treatment system and stormwater bypassing the treatment system)will be directed into the permanent retention/detention pond. If site constraints make locating the untreated stormwater storage pond difficult, the permanent retention/detention pond may be divided to serve as the untreated stormwater discharge pond and the post-treatment flow control pond. A berm or barrier must be used in this case so the untreated water does not mix with the treated water. Both untreated stormwater storage requirements, and adequate post- treatment flow control must be achieved. The post-treatment flow control pond's revised dimensions must be entered into the WWHM and the WWHM must be nm to confirn� compliance with the flow control requirement. Volurne II—Construction Stormwater Pollution Prevention -August 2012 4-122 Stormwater Pollution Prevention P I�' !an Appendix D — General Permit 33 Stormwafer Pollution Prevenfion Plan Appendix E — Site Inspection Forms (and Site Log) ', The results of each inspection shall be summarized in an inspection report or checklist I�' that is entered into or attached to the site log book. It is suggested that the inspection I report or checklist be included in this appendix to keep monitoring and inspection information in one document, but this is optionaL However, it is mandatory that this ' SWPPP and the site inspection forms be kept onsite at all times during construction, and '� that inspections be performed and documented as outlined below. ' At a minimum, each inspection report or checklist shall include: a. Inspection date/times b. Weather information: general conditions during inspection, approximate amount of precipitation since the last inspection, ,, and approximate amount of precipitation within the last 24 hours. I c. A summary or list of all BMPs that have been implemented, I, including observations of all erosion/sediment control structures or �� practices. ' d. The following shall be noted: � i. locations of BMPs inspected, ii. locations of BMPs that need maintenance, iii. the reason maintenance is needed, iv. locations of BMPs that failed to operate as designed or intended, and v. locations where additional or different BMPs are needed, and the reason(s) why e. A description of stormwater discharged from the site. The presence of suspended sediment, turbid water, discoloration, and/or oil sheen shall be noted, as applicable. f. A description of any water quality monitoring performed during inspection, and the results of that monitoring. g. General comments and notes, including a brief description of any BMP r repairs, maintenance or installations made as a result of the inspection. h. A statement that, in the judgment of the person conducting the site inspection, the site is either in compliance or out of compliance with the terms and conditions of the SWPPP and the NPDES permit. If the site inspection indicates that the site is out of compliance,the inspection report shall include a summary of the i4 Sformwafer Pollution Preventron Plan remedial actions required to bring the site back into compliance, as well as a schedule of implementation. i. Name, title, and signature of person conducting the site inspection; and the following statement: "I certify under penalty of law that this report is true, accurate, and complete, to the best of my knowledge and belief'. When the site inspection indicates that the site is not in compliance with any terms and conditions of the NPDES permit, the Permittee shall take immediate action(s) to: stop, contain, and clean up the unauthorized discharges, or otherwise stop the noncompliance; conect the problem(s); implement appropriate Best Management Practices (BMPs), and/or conduct maintenance of existing BMPs; and achieve compliance with all applicable standards and permit conditions. In addition, if the noncompliance causes a threat to human health or the environment, the Permittee shall comply with the Noncompliance Notification requirements in Special Condition SS.F of the permit. 35 Stormwafer Pollution Prevention Plan Site Inspection Form General Information Project Name: I Inspector Name: Title: CESCL # : Date: Time: Inspection Type: ❑ After a rain event ❑ Weekly ❑ Turbidity/transparency benchmark exceedance ❑ Other Weather Precipitation Since last inspection In last 24 hours Description of General Site Conditions: Inspection of BMPs Element 1: Mark Clearing Limits BMP: Location �spected Functioning problem/Corrective Action Y N Y N NIP BMP: ' Location Inspected Functioning problem/Corrective Action Y N Y N NIP Element 2: Establish Construction Access BMP: Inspected Functioning Location Y N Y N NIP Problem/Conective Action , BMP: II Location Inspected Functioning problem/Corrective Action Y N Y N NIP ' I �� I � 36 ' Stormwater Pollution Prevention Plan Element 3: Control Flow Rates BMP: Inspected Functioning Location y N Y N NIP Problem/Conective Action BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP Element 4: Install Sediment Controls BMP: Location �spected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP BMP: Location �spected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP 37 Sformwater Pollution Prevention Plan � Element S: Stabilize Soils BMP: Inspected Functioning Location y N Y N NII' Problem/Corrective Action BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP BMP: Location �spected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP � Element 6: Protect Slopes I, BMP: Inspected Functioning Location y N Y N NIP Problem/Conective Action BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP 38 Stormwater Pollution Prevention Plan � Element 7: Protect Drain Inlets BMP: Inspected Functioning Location y N Y N NIP Problem/Corrective Action BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP Elen:ent 8: Stabilize Channels and Dutlets BMP: Location �spected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIl' 39 Stormwater Pollution Prevention Plan � Element 9: Control Pollutants BMP: Inspected Functioning Location y N Y N NIP Problem/Corrective Action BMP: Location �spected Functioning problem/Corrective Action Y N Y N NIP Elenzent 10: Control Dewatering BMP: Location Inspected Functioning problem/Corrective Action Y N Y N NIP BMP: Location �spected Functioning problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning problem/Conective Action Y N Y N NIP ao Stormwater Pollution Prevention Plan Stormwater Dischar es From the Site I Observed? Problem/Corrective Action I Y �N Location Turbidity Discoloration Sheen Location Turbidity Discoloration Sheen 41 Stormwater Pollufion Prevention Plan Water Quality Monitorin Was any water quality monitoring conducted? � Yes ❑ No If water quality monitoring was conducted, record results here: If water quality monitoring indicated turbidity 250 NTU or greater; or transparency 6 cm or less, was Ecology notified by phone within 24 hrs? c Yes ❑ No lf Ecology was notified, indicate the date, time, contact name and phone number below: Date: Time: Contact Name: Phone #: General Comments and Notes Include BMP re airs, maintenance, or installations made as a result of the ins ection. Were Photos Taken? ❑ Yes ❑ No If hotos taken, describe hotos below: =�2 Sformwafer Pollution Prevention Plan I Appendix F — Engineering Calculations 43