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Solera Subdivision
Drainage Report
December 2020
Solera Subdivision
i
Drainage Report
December 2020
Prepared for:
DevCo, LLC
10900 NE 8th Street, Suite 1200
Bellevue, WA 98004
Prepared by:
Jeremy Febus, PE, LEED AP
Joe Neuzil, EIT
KPFF Consulting Engineers
1601 Fifth Avenue, Suite 1600
Seattle, WA 98101
(206) 622-5822
KPFF Project No. 117659
12/15/2020
Solera Subdivision
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This Page Intentionally Left Blank
Solera Subdivision
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Table of Contents
1. Project Overview .......................................................................................................................... 1
2. Existing Conditions ...................................................................................................................... 2
3. Conditions and Requirements Summary ..................................................................................... 3
Core Requirement No. 1: Discharge at The natural Location ...................................................... 3
Core Requirement No. 2: Offsite Analysis ..................................................................................... 3
Core Requirement No. 3: Flow Control .......................................................................................... 3
Core Requirement No. 4: Conveyance System ............................................................................. 3
Core Requirement No. 5: Construction Stormwater Pollution prevention ................................... 3
Core Requirement No. 6: Maintenance and Operations .............................................................. 3
Core Requirement No. 7: Financial Guarantees and Liability ....................................................... 3
Core Requirement No. 8: water quality ......................................................................................... 3
Core Requirement No. 9: On-Site BMPS ....................................................................................... 4
special requirement No. 1: Other Adopted Area-Specific Requirements ..................................... 4
special requirement No. 2: Flood Hazard Area Delineation .......................................................... 4
special requirement No. 3: Flood Protection Facilities .................................................................. 4
special requirement No. 4: Source Control .................................................................................... 4
special requirement No. 5: oil control ............................................................................................ 4
special requirement No. 6: aquifer protection areas ..................................................................... 4
4. Off-Site Analysis ........................................................................................................................... 5
3.1 upstream analysis ..................................................................................................................... 5
3.2 Downstream analysis ................................................................................................................ 5
5. Flow Control Analysis and Design ............................................................................................... 7
6. Water Quality Analysis and Design .............................................................................................. 9
6.1 Water Quality Requirement ...................................................................................................... 9
6.2 On-site BMP Requirement ..................................................................................................... 10
7. Conveyance System Analysis and Design ................................................................................. 10
8. Esc Analysis and Design ............................................................................................................ 11
9. Special Reports and Studies ...................................................................................................... 11
10. Bond Quantities and Declaration of Covenant .......................................................................... 11
Solera Subdivision
iv
List of Figures
Figure 1-1: Site Map ...................................................................................................................................... 1
Figure 1-2: Site Topography .......................................................................................................................... 2
Figure 4-1: Predeveloped Areas .................................................................................................................... 7
Figure 4-2: Developed Areas ......................................................................................................................... 8
Figure 5-1: Surface Runoff Basins ................................................................................................................ 9
List of Tables
Table 4-1: MGS Flood Peak Flow Rate Results ............................................................................................ 8
Appendices
Appendix A
Existing Conditions Site Map
Proposed Conditions Site Plan
Appendix B
Flow Control Applications Map
MGS Flood Peak Flow Report
MGS Flood Bioretention Report
Appendix C
Geotechnical Report
Infiltration Test Report
Drainage Report – Solera Unit Lot Subdivision
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1. Project Overview
The Solera Subdivision is a proposed residential and mixed use development at the northern corner of NE 10th
Ave and Sunset Blvd in Renton, Washington. The project consists of 96 for-sale town home units,
approximately 551 apartment units and roughly 39,000 sq ft of non-residential or commercial space. The
project consists of 6 existing parcels which will be subdivided into 4 parcels including realignment and
dedication of a portion of Jefferson Avenue NE ROW totaling 11.8 acres (Figure 1-1). The realigned and
expanded public right-of-ways will bisect the site connecting NE 12th Street to NE 10th Street and Harrington
Place to NE Sunset Boulevard. Additional frontage ROW dedications will be provided as well.
Figure 1-1: Site Map
SITE
Drainage Report – Solera Unit Lot Subdivision
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2. Existing Conditions
The site is substantially developed and paved in its existing condition. The current use, the Greater Hi-Lands
Shopping Center and its accompanying surface parking lot occupy the majority of the site. A 1.1 acre parcel, in
the southwest corner of the site, is undeveloped - consisting of lawn and gravel. The majority of the site slopes
to the southwest at grades of 2-5%. The northern extent of the project site, near the existing US Bank building,
slopes toward NE 12th St at grades of 2-5%. See Figure 2-1 for an overview of site topography.
Figure 1-2: Site Topography
Drainage Report – Solera Unit Lot Subdivision
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3. Conditions and Requirements Summary
In compliance to the City of Renton city code, proposed development shall be in accordance with a city
amended version of the 2016 King County Surface Water Manual City titled The Renton Surface Water Manual
(RSWM).
CORE REQUIREMENT NO. 1: DISCHARGE AT THE NATURAL L OCATION
The project proposes to connect to existing public stormwater conveyance systems in NE 10th St and NE 12th
St. These storm drains converge within ¼ mile downstream, and so the site is treated as a single Threshold
Discharge Area.
CORE REQUIREMENT NO. 2: OFFSITE ANALYSIS
An offsite analysis has been conducted, see Section 3.
CORE REQUIREMENT NO. 3: FLOW CONTROL
According to the Flow Control Application Map from the RSWM, the development is required to meet the Peak
Rate Flow Control Standard – Match Existing. Developed flows must match 2, 10 and 100-yr peak flows which
existed on site prior to May 1979. Existing improvements on the site were built in phases over a range of
years from 1958 to 1977, and so for the purposes of this analysis, “existing conditions” are defined as the
current land use.
CORE REQUIREMENT NO. 4: CONVEYANCE SYSTEM
Proposed conveyance system elements, both onsite and offsite, shall be analyzed, designed and constructed
according to RSWM requirements. Conveyance system calculations will be provided during construction
document permitting following entitlement.
CORE REQUIREMENT NO. 5: CONSTRUCTION STORMWATER PO LLUTION
PREVENTION
Erosion and Sediment Control measures and Stormwater Pollution Prevention and Spill Control measures will
be applied through a Construction Stormwater Pollution Prevention (CSWPP) plan to be prepared during
construction permitting.
CORE REQUIREMENT NO. 6: MAINTENANCE AND OPERATIONS
Operation and Maintenance measures for stormwater infrastructure will be provided prior to Final Plat
Submittal.
CORE REQUIREMENT NO. 7: FINANCIAL GUARANTEES AND LI ABILITY
Bond quantities for the City of Renton will be provided prior to construction permitting.
CORE REQUIREMENT NO. 8: WATER QUALITY
The project is required to apply Enhanced Basic WQ treatment due to the Commercial and multifamily land
uses. To achieve this bioretention facilities have been proposed throughout the site, See Section 5 for a more
detailed analysis.
Drainage Report – Solera Unit Lot Subdivision
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CORE REQUIREMENT NO. 9: ON-SITE BMPS
The project is satisfying the on-site BMP requirement by demonstrating compliance with the LID Performance
Standard as described in Section 1.2.9.1.B in the RSWM. The LID Performance standard is being achieved
through the use of bioretention and underground infiltration facilities dispersed throughout the development.
See Section 6 for a more detailed analysis.
SPECIAL REQUIREMENT NO. 1: OTHER ADOPTED AREA-SPECI FIC
REQUIREMENTS
This project is within the Sunset Area Surface Water Master Plan (CH2M HILL, 2011) which requires the
developer to install an 8 ft wide bioretention facility along the south side of NE 12th St.
SPECIAL REQUIREMENT NO. 2: FLOOD HAZARD AREA DELINE ATION
This project is not located in a flood hazard area.
SPECIAL REQUIREMENT NO. 3: FLOOD PROTECTION FACILIT IES
This project does not modify or use a flood protection facility.
SPECIAL REQUIREMENT NO. 4: SOURCE CONTROL
Source control requirements apply to projects proposing a commercial building or which require a Commercial
Site Development permit. The commercial development will apply the appropriate BMP’s required during
building permits.
SPECIAL REQUIREMENT NO. 5: OIL CONTROL
The project does not classify as a high use site and is thus exempt from the Special Requirement #5.
SPECIAL REQUIREMENT NO. 6: AQUIFER PROTECTION AREAS
The project is within wellhead protection zone 2. However, the project is not proposing any of the drainage
facilities mentioned in Section 1.3.6 of the RSWM and thus special requirement No. 6 is not applicable.
Drainage Report – Solera Unit Lot Subdivision
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4. Off-Site Analysis
3.1 UPSTREAM ANALYSIS
The site is on a ridgeline. There are no upstream basins that drain onto the project site.
3.2 DOWNSTREAM ANALYSIS
Approximately 90% of the existing development drains to the southwest, where it is collected in the public
conveyance systems within NE 10th St. The Sunset Neighborhood Park, directly across NE 10th St, has
existing bioretention cells which were sized to accommodate 0.77 acres of the flow from the Solera site. The
rest of the existing Solera runoff is conveyed west along 10th St toward Sunset Blvd. The remaining
approximately 10% of existing runoff flows to the north where it discharges to the public stormwater
conveyance system within NE 12th St. Flow from all of three of these discharge locations converge within ¼
mile downstream.
The downstream path for this site’s runoff is contained within a piped public conveyance system.
Approximately 1 mile downstream, the piped system crosses under Interstate 405 and outfalls into a series of
wetlands. Runoff flows through the wetlands until it reaches a creek which flows to Lake Washington. The
Sunset Area Storm Water Master Plan notes that there are no known capacity issues in the drainage system
downstream of our site.
Drainage Report – Solera Unit Lot Subdivision
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Figure 3-1: 1-Mile Downstream Flow Path
Drainage Report – Solera Unit Lot Subdivision
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5. Flow Control Analysis and Design
According to the City of Redmond Flow Control Application Map, the project falls within the Peak Flow Control
Standard Region (Existing Site Conditions, See Appendix B). The Peak Flow Control Standard states that the
developed condition peak flows for the 2, 10 and 100 year storm must be less than peak flows that existed on
site prior to May 1979.
The King County Assessor’s Reports indicate that the latest improvements to the developed parcels were
made in 1977. Street frontages are assumed to be to their current conditions prior to on-site parcel
improvements in 1977: Sunset Blvd, Harrington Pl, Kirkland Avenue NE, and NE 12th Street. See Figures 4-1
and 4-2 for a comparison of impervious and pervious surfaces in the existing and developed conditions. The
existing surveyed conditions were modeled as existing conditions in this analysis.
Figure 5-1: Predeveloped Areas
Drainage Report – Solera Unit Lot Subdivision
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Figure 5-2: Developed Areas
Table 5-1: MGS Flood Peak Flow Rate Results
The proposed improvements to the site will create more pervious surface than existed in May 1979. As a
result, without the implementation of any flow control measures, the developed peak flows are less than
predeveloped peak flows in the 2, 10 and 100yr condition – complying with Core Requirement #3.
Predeveloped Peak Flows (cfs) Developed Peak Flows (cfs)
2 yr 3.25 2.78
10 yr 4.56 4.08
100 yr 6.10 5.33
Drainage Report – Solera Unit Lot Subdivision
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6. Water Quality Analysis and LID Performance Standard
Design
The project is proposing to construct infiltrating bioretention cells to satisfy both Core Requirement No. 8
Water Quality and Core Requirement No. 9 On-site BMPs.
6.1 WATER QUALITY REQUIREMENT
Over 50% of the developed site will be commercial and multifamily land use. According to the RSWM this
triggers the need for Enhanced Basic Water Quality treatment. The treatment goal of Enhanced Basic Water
Requirement can be achieved by treating targeted surface runoff with bioretention (Enhanced Basic Option 4,
6.1.2 RSWM).
The project site has been subdivided into 68 sub-basins (Figure 6-1)
Figure 6-1: Surface Runoff Basins
The site grading allows directs sub-basin runoff from new pollution generating impervious surface into
bioretention facilities through a curb inlet. Runoff treated in bioretention planters will then infiltrate into native
soils. Surface runoff from street frontage improvements will be treated in the same way (basins 45-48;62-68).
Bioretention facilities have been sized using MGS Flood methodology to treat 91% of runoff entering the cell.
An infiltration rate of 6 inches per hour was used for the amended soil and an infiltration rate of 0.7 inches per
hour was used for the underlying native soils consistent with infiltration test results completed by Earth
Solutions Northwest LLC (report in Appendix C). The geotechnical report provides tested on-site infiltration
rates ranging from 2-20 inches per hour. The rate of 0.7 inches per hour is a conservative infiltration rate used
for design, taking the lowest tested rate (2 inches per hour) and applying a safety factor of 3. The MGS Flood
Report demonstrating compliance is located in Appendix B.
Drainage Report – Solera Unit Lot Subdivision
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6.2 ON-SITE BMP REQUIREMENT
According to section 1.2.9 of the RWSM, Core Requirement #9 can be satisfied by,
1) Application of BMPs to the maximum extent feasible
or
2) Using a continuous runoff model to demonstrate compliance with the Low Impact Development (LID)
Performance Standard.
This development has opted to use the LID performance Standard, “stormwater discharges shall match
developed discharge durations to pre-developed durations for the range of pre-developed discharge rates from
8% of the 2-year peak flow to 50% of the 2-yr peak flows.” The pre-developed condition is modeled as forested
to comply with this approach. The development has proposed to meet this requirement primarily through
bioretention cells distributed throughout the site. For Mixed-Use Building B, an underground infiltration facility
is proposed for all roof runoff. Using the same basins shown in Figure 6-1, duration flows for each basin were
modeled using MGS flood methodology. Each individual basin, routed through the infiltrating bioretention
facility, meet discharge rates from 8% of the 2-year peak flow to 50% of the 2-year peak flow meeting the LID
performance standard. Basin 30 and 31 are routed to an underground infiltration facility, which meets
compliance for the LID performance standard.
The project is also compliant with the LID performance standard site-wide. Appendix B provides a report
which analyzes the site as a single basin. Bioretention cells function in parallel, not in series, and so every
basin was combined to show compliance for the flow rates from the entire site for a single point of compliance.
As shown in Appendix B, the overall site area flow rates are in accordance with the LID performance standard.
The input for the continuous runoff model shows a single basin (sum of all sub-basins) discharging to a single
bioretention facility (area is a sum of all on-site bioretention facilities). Overflow from bioretention areas will be
routed via on-site conveyance structures and drain lines to the existing public conveyance system. Each
individual basin’s MGS Flood Reports as well as the composite MGS Flood report is provided in Appendix B.
6.3 ON-SITE BMP MIXED USE LOTS
Mixed-use lots will use a combination of bio-retention planters and underground infiltration facilities to meet
100% of the LID performance standard for roof areas. Meeting this requirement strictly through the use of bio-
retention planters and underground infiltration facilities would require approximately 3,000 square feet of
infiltration area per mixed use Parcel. Soil Amendment is proposed to meet BMP requirements for new
pervious surfaces on the mixed-use parcels in accordance with The City of Renton Surface Water Design
Manual Appendix C.2.13. The mixed-use parcel roof areas, as well as the pervious surface areas, were
included in the basin representing the entire site described in Section 6.2. The actual BMP sizing and
placement will be refined and fully documented through individual site plan entitlements for each mixed-use
parcel.
7. Conveyance System Analysis and Design
No existing capacity issues are known within the downstream conveyance system. A detailed analysis will be
performed for the projects receiving conveyance system during construction document permitting. Proposed
conveyance system elements, both onsite and offsite, shall be analyzed, designed and constructed according
to RSWM requirements. Conveyance system calculations will be provided during construction document
permitting following entitlement.
Drainage Report – Solera Unit Lot Subdivision
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8. Esc Analysis and Design
Erosion and Sediment Control measures and Stormwater Pollution Prevention and Spill Control measures will
be applied through a Construction Stormwater Pollution Prevention (CSWPP) plan.
9. Special Reports and Studies
The Sunset Area Surface water Master Plan (CH2M HILL, 2011) discusses the City of Renton’s surface water
management program within the Sunset Area. The Master Plan requires this project to install an 8’ bioretention
facility along the south side of NE 12th St.
10. Bond Quantities and Declaration of Covenant
Bond quantities for the City of Renton will be provided prior to construction permitting.
Drainage Report – Solera Unit Lot Subdivision
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Appendix A
1. Existing Conditions Site Map
2. Proposed Conditions Site Plan
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HARRINGTON PLACE NE
(A DEDICATED PUBLIC RIGHT OF
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(A DEDICATED PUBLIC RIGHT OF WAY)
SUNSET LANE NE
(A DEDICATED PUBLIC RIGHT OF WAY)NE 10TH STREET(A DEDICATED PUBLIC RIGHT OF WAY)SUNSET LANE NE
(A DEDICATED PUBLIC RIGHT OF WAY)
NE SUNSET BOULEVARD
(A DEDICATED PUBLIC RIGHT OF WAY)
PERVIOUS: 1.8 ACRES
IMPERVIOUS = 10.8 ACRES
SUNSET BLVD KIRKLAND AVE NENE 12TH
ST
HARRINGTON PL NE
NE 10TH STEXISTING CONDITIONS
1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
NW 1/4 OF THE NW 1/4 AND THE NE 1/4 OF THE NW 1/4 SECTION 9, TOWNSHIP 23 NORTH, RANGE 05 EAST, W.M.
Drainage Report – Solera Subdivision
Appendix B
Appendix B
1. Flow Control Applications Map
2. MGS Flood Peak Flow Report
3. MGS Flood Bioretention Report
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Flow Control Application Map
Reference 15-A
Date: 01/09/2014
Flow Control Standards
Peak Rate Flow Control Standard (Existing Site Conditions)
Flow Control Duration Standard (Existing Site Conditions)
Flow Control Duration Standard (Forested Conditions)
Flood Problem Flow
Unincorporated King County Flow Control Standards
Renton City Limits
Potential Annexation Area
PROJECT SITE
—————————————————————————————————
MGS FLOOD
PROJECT REPORT
Program Version: MGSFlood 4.52
Program License Number: 200410007
Project Simulation Performed on: 11/02/2020 5:33 AM
Report Generation Date: 11/02/2020 5:36 AM
—————————————————————————————————
Input File Name: 2020-11-1_Peaks.fld
Project Name: Solera
Analysis Title: Peak Flows
Comments:
———————————————— PRECIPITATION INPUT ————————————————
Computational Time Step (Minutes): 60
Extended Precipitation Time Series Selected
Climatic Region Number: 3
Full Period of Record Available used for Routing
Precipitation Station : 95004005 Puget West 40 in_5min 10/01/1939-10/01/2097
Evaporation Station : 951040 Puget West 40 in MAP
Evaporation Scale Factor : 0.750
HSPF Parameter Region Number: 1
HSPF Parameter Region Name : USGS Default
********** Default HSPF Parameters Used (Not Modified by User) ***************
********************** WATERSHED DEFINITION ***********************
Predevelopment/Post Development Tributary Area Summary
Predeveloped Post Developed
Total Subbasin Area (acres) 12.600 12.600
Area of Links that Include Precip/Evap (acres) 0.000 0.000
Total (acres) 12.600 12.600
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Grass 1.800
Impervious 10.800
----------------------------------------------
Subbasin Total 12.600
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Grass 3.610
Impervious 8.990
----------------------------------------------
Subbasin Total 12.600
************************* LINK DATA *******************************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
************************* LINK DATA *******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
**********************FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
Number of Links: 0
***********Groundwater Recharge Summary *************
Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures
Total Predeveloped Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Subbasin 1 213.980
_____________________________________
Total: 213.980
Total Post Developed Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Subbasin 1 429.149
_____________________________________
Total: 429.149
Total Predevelopment Recharge is Less than Post Developed
Average Recharge Per Year, (Number of Years= 158)
Predeveloped: 1.354 ac-ft/year, Post Developed: 2.716 ac-ft/year
***********Water Quality Facility Data *************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 0
***********Compliance Point Results *************
Scenario Predeveloped Compliance Subbasin: Subbasin 1
Scenario Postdeveloped Compliance Subbasin: Subbasin 1
*** Point of Compliance Flow Frequency Data ***
Recurrence Interval Computed Using Gringorten Plotting Position
Predevelopment Runoff Postdevelopment Runoff
Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs)
----------------------------------------------------------------------------------------------------------------------
2-Year 3.248 2-Year 2.773
5-Year 3.962 5-Year 3.480
10-Year 4.552 10-Year 4.076
25-Year 5.188 25-Year 4.672
50-Year 5.546 50-Year 4.991
100-Year 6.095 100-Year 5.328
200-Year 6.724 200-Year 6.176
500-Year 7.557 500-Year 7.309
** Record too Short to Compute Peak Discharge for These Recurrence Intervals
**** Flow Duration Performance ****
Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): -38.5% PASS
Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): -38.5% PASS
Maximum Excursion from Q2 to Q50 (Must be less than 10%): -34.5% PASS
Percent Excursion from Q2 to Q50 (Must be less than 50%): 0.0% PASS
-------------------------------------------------------------------------------------------------
MEETS ALL FLOW DURATION DESIGN CRITERIA: PASS
-------------------------------------------------------------------------------------------------
**** LID Duration Performance ****
Excursion at Predeveloped 8%Q2 (Must be Less Than 0%): -9.8% PASS
Maximum Excursion from 8%Q2 to 50%Q2 (Must be Less Than 0%): -10.4% PASS
-------------------------------------------------------------------------------------------------
MEETS ALL LID DURATION DESIGN CRITERIA: PASS
-------------------------------------------------------------------------------------------------
—————————————————————————————————
MGS FLOOD
PROJECT REPORT
Program Version: MGSFlood 4.52
Program License Number: 200410007
Project Simulation Performed on: 12/07/2020 5:22 PM
Report Generation Date: 12/07/2020 5:23 PM
—————————————————————————————————
Input File Name: LID Sizing Mixed Use Building B.fld
Project Name: Solera Bioretention
Analysis Title:
Comments:
———————————————— PRECIPITATION INPUT ————————————————
Computational Time Step (Minutes): 15
Extended Precipitation Time Series Selected
Climatic Region Number: 15
Full Period of Record Available used for Routing
Precipitation Station : 96004005 Puget East 40 in_5min 10/01/1939-10/01/2097
Evaporation Station : 961040 Puget East 40 in MAP
Evaporation Scale Factor : 0.750
HSPF Parameter Region Number: 1
HSPF Parameter Region Name : USGS Default
********** Default HSPF Parameters Used (Not Modified by User) ***************
********************** WATERSHED DEFINITION ***********************
Predevelopment/Post Development Tributary Area Summary
Predeveloped Post Developed
Total Subbasin Area (acres) 1.998 1.950
Area of Links that Include Precip/Evap (acres) 0.000 0.048
Total (acres) 1.998 1.998
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Forest 1.998
----------------------------------------------
Subbasin Total 1.998
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Impervious 1.950
----------------------------------------------
Subbasin Total 1.950
************************* LINK DATA *******************************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
PARCEL B (MIXED-USE) LID
COMPLIANCE FOR ROOF AREA
************************* LINK DATA *******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
------------------------------------------
Link Name: infiltration
Link Type: Bioretention Facility
Downstream Link: None
Base Elevation (ft) : 100.00
Riser Crest Elevation (ft) : 100.50
Storage Depth (ft) : 0.50
Bottom Length (ft) : 100.0
Bottom Width (ft) : 21.0
Side Slopes (ft/ft) : L1= 0.00 L2= 0.00 W1= 0.00 W2= 0.00
Bottom Area (sq-ft) : 2100.
Area at Riser Crest El (sq-ft) : 2,100.
(acres) : 0.048
Volume at Riser Crest (cu-ft): 1,995.
(ac-ft) : 0.046
Infiltration on Bottom only Selected
Soil Properties
Biosoil Thickness (ft) : 1.50
Biosoil Saturated Hydraulic Conductivity (in/hr) : 6.00
Biosoil Porosity (Percent) : 30.00
Maximum Elevation of Bioretention Soil : 101.00
Native Soil Hydraulic Conductivity (in/hr) : 1.00
Riser Geometry
Riser Structure Type : Circular
Riser Diameter (in) : 6.00
Common Length (ft) : 0.000
Riser Crest Elevation : 100.50 ft
Hydraulic Structure Geometry
Number of Devices: 0
**********************FLOOD FREQUENCY AND DURATION STATISTICS*******************
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
Number of Links: 1
********** Link: infiltration ********** Link WSEL Stats
WSEL Frequency Data(ft)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) WSEL Peak (ft)
======================================
1.05-Year 100.648
1.11-Year 100.678
1.25-Year 100.701
2.00-Year 100.838
3.33-Year 100.925
5-Year 100.995
10-Year 101.112
25-Year 101.326
50-Year 101.441
100-Year 101.556
***********Groundwater Recharge Summary *************
Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures
Total Predeveloped Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Subbasin 1 344.513
_____________________________________
Total: 344.513
Total Post Developed Recharge During Simulation
Model Element Recharge Amount (ac-ft)
-----------------------------------------------------------------------------------------------
Subbasin: Subbasin 1 0.000
Link: infiltration 759.933
_____________________________________
Total: 759.933
Total Predevelopment Recharge is Less than Post Developed
Average Recharge Per Year, (Number of Years= 158)
Predeveloped: 2.180 ac-ft/year, Post Developed: 4.810 ac-ft/year
***********Water Quality Facility Data *************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
********** Link: infiltration **********
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 874.28
Inflow Volume Including PPT-Evap (ac-ft): 895.04
Total Runoff Infiltrated (ac-ft): 759.93, 84.90%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 134.44
Secondary Outflow To Downstream System (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered)/Total Volume: 84.90%
***********Compliance Point Results *************
Scenario Predeveloped Compliance Subbasin: Subbasin 1
Scenario Postdeveloped Compliance Link: infiltration
*** Point of Compliance Flow Frequency Data ***
Recurrence Interval Computed Using Gringorten Plotting Position
Predevelopment Runoff Postdevelopment Runoff
Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs)
----------------------------------------------------------------------------------------------------------------------
2-Year 4.258E-02 2-Year 0.457
5-Year 6.939E-02 5-Year 0.554
10-Year 9.350E-02 10-Year 0.616
25-Year 0.119 25-Year 0.715
50-Year 0.151 50-Year 0.764
100-Year 0.164 100-Year 0.809
200-Year 0.255 200-Year 0.875
500-Year 0.378 500-Year 0.963
** Record too Short to Compute Peak Discharge for These Recurrence Intervals
**** Flow Duration Performance ****
Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): -7.1% PASS
Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): 398.9% FAIL
Maximum Excursion from Q2 to Q50 (Must be less than 10%): 99999.0% FAIL
Percent Excursion from Q2 to Q50 (Must be less than 50%): 100.0% FAIL
-------------------------------------------------------------------------------------------------
FLOW DURATION DESIGN CRITERIA: FAIL
-------------------------------------------------------------------------------------------------
**** LID Duration Performance ****
Excursion at Predeveloped 8%Q2 (Must be Less Than 0%): -89.1% PASS
Maximum Excursion from 8%Q2 to 50%Q2 (Must be Less Than 0%): -7.1% PASS
-------------------------------------------------------------------------------------------------
MEETS ALL LID DURATION DESIGN CRITERIA: PASS
-------------------------------------------------------------------------------------------------
Drainage Report – Solera Subdivision
Appendix C
Appendix C
Geotechnical Report
EarthSolutionsNWLLC
EarthSolutions
NW LLC
Geotechnical Engineering
Geology
Environmental Scientists
Construction Monitoring
1805 -136th Place N.E.,Suite 201 Bellevue,WA 98005
(425)449-4704 Fax (425)449-4711
www.earthsolutionsnw.com
GEOTECHNICAL ENGINEERING STUDY
RENTON HIGHLANDS TOWNHOMES
NORTHEAST SUNSET BOULEVARD
RENTON,WASHINGTON
ES-5719
Drwn.
Checked Date
Date Proj.No.
Plate
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Vicinity Map
Renton Highlands Townhomes
Renton,Washington
MRS
CGH
01/29/2018
Jan.2018
5719
1
NORTH
NOTE:This plate may contain areas of color.ESNW cannot be
responsible for any subsequent misinterpretation of the information
resulting from black &white reproductions of this plate.
Reference:
King County,Washington
Map 626
By The Thomas Guide
Rand McNally
32nd Edition
SITE
Plate
Proj.No.
Date
Checked By
Drwn.ByEarthSolutionsNWLLCGeotechnicalEngineering,ConstructionMonitoringandEnvironmentalSciencesEarthSolutionsNWLLCEarthSolutionsNWLLCBoringLocationPlanRentonHighlandsTownhomesRenton,WashingtonMRS
CGH
01/29/2018
5719
2
NORTH
NOT -TO -SCALE
NOTE:This plate may contain areas of color.ESNW cannot be
responsible for any subsequent misinterpretation of the information
resulting from black &white reproductions of this plate.
NOTE:The graphics shown on this plate are not intended for design
purposes or precise scale measurements,but only to illustrate the
approximate test locations relative to the approximate locations of
existing and /or proposed site features.The information illustrated
is largely based on data provided by the client at the time of our
study.ESNW cannot be responsible for subsequent design changes
or interpretation of the data by others.
LEGEND
Approximate Location of
ESNW Boring,Proj.No.
ES-5719,Dec.2017
Subject Site
Existing Building
KIRKLAND AVENUE N.E. N.E. SUNSET BOULEVARDN.E. 12TH STREET
HARRINGTON AVENUE N.E.N.E.10T
H
ST
R
EETApartments SUNSET LANE N.E.B-1
B-2
B-3
B-4
B-5B-6
B-7
B-8
B-9
B-10
B-11
B-12
B-13
B-1
HARRINGTON PL. N.E.
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CANTILEVER &SINGLE TIEBACK WALL
D =Pile Embedment
(per Structural Eng.)
2'
H
(Wall Height)
Active
Earth
Pressure
Passive
Earth
Pressure
EFP=350pcf
EFP=35pcf
Surcharge
(W here Applicable)
Traffic Surcharge or Building Surcharge
(W here Applicable)
Excavation Level
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAW ING
NOTES:
Diagram for pressure distribution illustration
only,not a design drawing.
Passive Pressure includes a factor of
safety of 1.5.
For adjacent building or traffic surcharge
see text.
NOTE:
See text for recommended
Slope Backfill and At-Rest
Pressures.
Neglect Upper 2 feet
of Passive Pressure
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NO LOAD ZONE
D =Pile Embedment
(per Structural Eng.)
H
(Wall Height)
Traffic Surcharge or Building Surcharge
(W here Applicable)
Excavation Level
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAW ING
H/4 60
Tieback No Load
Zone
Renton Highlands Townhomes
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SHORING WALL DRAINAGE
W ood Lagging
Native
Soil
Excavation
PVC Tightline
Structural Fill
Foundation
(per Plan)
Drain Grate
Waterproofing and Insulation
per Architectural Plan
Continuous Sheet Drain
(Placed with Filter Fabric
Facing Shoring)
Concrete Facing
Slab-On-Grade Floor
(per Plan)
NOTE:Drain through wall should be installed at middle of lagging.
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAW ING
Renton Highlands Townhomes
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RETAINING WALL DRAINAGE DETAIL
NOTES:
Free-draining Backfill should consist
of soil having less than 5 percent fines.
Percent passing No.4 sieve should be
25 to 75 percent.
Sheet Drain may be feasible in lieu
of Free-draining Backfill,per ESNW
recommendations.
Drain Pipe should consist of perforated,
rigid PVC Pipe surrounded with 1-inch
Drain Rock.
LEGEND:
Free-draining Structural Backfill
1-inch Drain Rock
18"Min.
Structural
Fill
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Renton Highlands Townhomes
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FOOTING DRAIN DETAIL
Slope
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
18"Min.
NOTES:
Do NOT tie roof downspouts
to Footing Drain.
Surface Seal to consist of
12"of less permeable,suitable
soil.Slope away from building.
LEGEND:
Surface Seal:native soil or
other low-permeability material.
1-inch Drain Rock
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAW ING
Renton Highlands Townhomes
Renton,Washington
MRS
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Jan.2018
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