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Dalpay Preliminary Short Plat
Level 1 Downstream Analysis and
Preliminary Drainage Control Plan
June 2019
Dalpay Preliminary Short Plat June 2019
Level 1 Downstream Analysis and Preliminary Drainage Control Plan
r18067 Dalpay Technical Information Report 2019-06.docx
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TABLE OF CONTENTS
1.0 Project Overview .................................................................................................................. 1
2.0 Offsite Analysis .................................................................................................................... 4
Task 1. Define and Map Study Area
Task 2. Information Review
Task 3. Field Inspection
Task 4. Drainage System Description and Problem Description
3.0 Preliminary Drainage Control Plan ..................................................................................... ..7
4.0 Flow Control and Water Quality Facility Analysis ................................................................. 8
Part A. Existing Site Hydrology
Part B. Developed Site Hydrology
Part C. Performance Standards
Part D. Flow Control System
Part E. Water Quality System
FIGURES
Figure 1 Vicinity Map
Figure 2 Existing Site Aerial Photo
Figure 3 USGS Soils Map
Figure 4 Existing Conditions Map
Figure 5 Downstream Map
Figure 6 Preliminary Drainage Plan
Figure 7 Critical Areas Map
APPENDIX
A. King County W ater and Land Resources Division Drainage Complaint
Investigation Sheets (1/4 Mile and Minimum 1 Mile)
B. Geotechnical Report by Associated Earth Sciences, Inc., April 19, 2019
Dalpay Preliminary Short Plat June 2019
Level 1 Downstream Analysis and Preliminary Drainage Control Plan
r18067 Dalpay Technical Information Report 2019-06.docx
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1.0 Project Overview
Introduction
This report provides design data and analysis for the improvements proposed for the Dalpay Short
Plat five lot subdivision. The site is approximately 2.46 acres and is located at the northwesterly
corner of the intersection of SE Renton-Issaquah Road and 148th Avenue SE in the City of Renton,
Washington, also known as Tax Parcel No. 0323059120, situated in the southeast quarter of
Section 3, Township 23 North, Range 5 East, W.M.
As required by the 2017 City of Renton Surface Water Design Manual (COR SWDM), this report
includes a summary of the existing on-site and downstream conditions; proposed developed site
conditions; and the proposed stormwater control plan. This report also gives specific details on how
the project meets the minimum requirements specified in Section 1.2 of the 2017 COR SWDM.
Project Description
This project will provide the necessary site improvements required to serve the five single family
lots proposed with this short plat. The site is currently undeveloped with a few scattered trees and
shrubs/bushes/Himalayan blackberry within the property. The existing Greenes Creek to the west
of the site is surrounded by shrubs/bushes as seen in images 1 through 4 of this report.
Summary of Proposal
This is a request for Preliminary Subdivision approval for five single family residential lots, public
roads, public utilities (water, sewer, stormwater), and stormwater/critical area tracts on the existing
parcel. Stormwater control facilities will be designed per the 2017 City of Renton Surface Water
Design Manual requirements as identified above. The proposed road and permanent cul-de-sac
are designed in accordance with the 2016 King County Road Design and Construction Standards.
As the future project will disturb one acre or more and has stream buffer on-site, this Preliminary
Plat is subject to SEPA.
The total project site is approximately 2.46 acres. Currently undeveloped, the site is vegetated with
tall grasses, dense blackberry bushes, and scattered trees. The proposed stormwater system
proposes to follow similar existing drainage patterns, meeting flow control and water quality
requirements set forth by the City of Renton. A downstream analysis of the site up to the quarter
mile was prepared in Section 2 of this report.
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Level 1 Downstream Analysis and Preliminary Drainage Control Plan
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CORE REQUIREMENTS
The following is a preliminary description of how the Dalpay project will meet the Core Requirements
of the 2017 COR SWDM.
Core Requirement #1 – Discharge at the Natural Location
The proposed conditions will not alter the general downstream path. The proposed drainage
improvements will continue to route stormwater to the existing creek west of the property. The
proposed flow control structure will discharge stormwater to Greenes Creek. Refer to the Offsite
Analysis section (section 2) of this report for a description of the existing discharge point.
Core Requirement #2 – Offsite Analysis
A downstream drainage analysis has been completed and is included in this report.
Core Requirement #3 – Flow Control
Flow Control for the project area will be provided by the proposed vault and will be managed by a
flow restrictor located on the northwest corner of the property within the proposed stormwater tract.
The flow restrictor is designed to meet the flow control duration standard base on the historic
forested site conditions. MGS Flood modeling was used to confirm compliance with the 2017 COR
SWDM requirements. (Section 4)
Core Requirement #4 – Conveyance System
The design and analysis of the stormwater conveyance system for this project will comply with the
requirements of the 2017 COR SWDM. Detailed design and analysis of the conveyance system will
be completed in future engineering plan submittals.
Core Requirement #5 – Construction Stormwater Pollution Prevention
The design of the construction stormwater pollution prevention (CSPP) plans for the proposed
improvements will be per the requirements of the 2017 COR SWDM and included with future
engineering plan submittals.
Core Requirement #6 – Maintenance and Operation
Proposed stormwater facilities will be dedicated to the City of Renton by Dalpay Properties.
Core Requirement #7 – Financial Guarantees and Liability
This project will comply with all financial guarantees required by the City of Renton.
Core Requirement #8 – Water Quality Facilities
The project site is located in an area requiring Basic Water Quality Treatment. The Project proposes
to treat stormwater runoff from the proposed road and driveways before discharging runoff to the
existing Greenes Creek located west of the project.
Core Requirement #9 – On-site BMP’s
Design and analysis of Flow Control BMP’s will be per requirements of the 2017 COR SWDM.
Detailed design and analysis of flow control BMP’s will be included in future submittals.
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Level 1 Downstream Analysis and Preliminary Drainage Control Plan
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SPECIAL REQUIREMENTS
Special Requirement #1 – Other Adopted Area-Specific Requirements
The site does not fall under any other known adopted area specific requirements.
Special Requirement #2 – Flood Hazard Area Delineation
This project development is adjacent to a zone X flood hazard area per FEMA Flood Maps.
Special Requirement #3 – Flood Protection Facilities
This project does not rely on an existing flood protection facility for protection against hazards posed
by erosion or inundation or propose to modify or construct a new flood protection facility; therefore,
flood protection facilities are not required.
Special Requirement #4 – Source Control
The proposed development does not require a commercial building or commercial site development
permit; Therefore, water quality source control is not required.
Special Requirement #5 – Oil Control
This project does not have high use site characteristics; therefore, oil control BMP’s are not required.
Special Requirement #6 – Aquifer Protection Area
This project does not have high use site characteristics; therefore, oil control BMP’s are not required.
2.0 Off-Site Analysis
The following is a Level 1 downstream analysis, performed in accordance with the 2017 City of
Renton SWDM. A site visit was conducted by Goldsmith Engineering on October 26, 2018 to
investigate the onsite drainage systems, confirm downstream drainage paths, and evaluate
upstream tributary areas to the project site. The weather during the site visit was cloudy but dry with
a temperature of approximately 60 degrees Fahrenheit.
Task 1 – Define and Map Study Area
The topographical field survey was supplemented by City of Renton GIS drainage information, aerial
mapping, and information obtained by field investigation to further define and map the study area in
order to prepare the offsite analysis.
Task 2 – Information Review
As mentioned earlier, the City of Renton drainage maps show the project area within the May Creek
Basin. Based on the City of Renton GIS mapping data, there is an existing Class 2 wetland on the
west side of the site. The stream / wetland delineation performed by Altmann Oliver Associates has
confirmed there is no wetland present on-site, only an off-site wetland as shown on Figure 4.
According to the Washington State Department of Ecology Flood Hazard Maps, the project area is
not located within a Floodway or 100-year Floodplain.
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Task 3 – Field Inspection
The project area slopes north and west with slopes ranging from 8% to 15%. The site is covered
with shrubs/bushes near Greenes Creek on the west.
Task 4 – Drainage System Description and Problem Descriptions
The downstream drainage path was determined based on City of Renton GIS storm drainage maps,
site survey, and information gathered during a site visit. Refer to Figure 5 – Downstream Drainage
Map. As previously stated, runoff from the site flows north and west towards Greenes Creek. The
proposed drainage improvements will discharge stormwater from the detention facility to Greenes
Creek on the northwest corner of the property.
1. Runoff is discharged from the site to the existing Greenes Creek near the northwest corner
of the property boundary. Greenes Creek slopes north along the edge of the property. No
stormwater flow was observed during the time of visit.
2. Runoff is collected from the creek by an existing 24-inch bypass line.
3. Water flows west to existing storm drain man hole within Lyons Ave NE.
4. From this man hole, piping heads north for approximately 190 feet, discharging into Greenes
Creek.
5. Stormwater runoff flows north through a heavily vegetated creek, eventually out falling to
May Creek.
Task 5 – Mitigation of Existing or Potential Problems
As indicated previously, there are no existing problems on-site or downstream of the site. The
design of a stormwater control plan meeting the City of Renton requirements, including
recommended BMPs will mitigate any potential problems related to the development of the subject
site.
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Level 1 Downstream Analysis and Preliminary Drainage Control Plan
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Images 1 and 2 – Left image: center of Greenes Creek looking North.
Right image: West e dge of Greenes Creek looking East.
Imag es 3 and 4 – Left image : 24-inch pipe outfall with trash guard to Greenes Creek .
Right image: Greenes Creek looking North .
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Level 1 Downstream Analysis and Preliminary Drainage Control Plan
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OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE -1
Surface Water Design Manual, Core Requirement #2
Basin: Lake Washington Watershed Sub-basin Name: May Creek
Symbol Drainage
Component Type,
Name, and Size
Drainage Component
Description
Slope
(estimated)
Distance
from site
discharge
Existing
Problems
Potential
Problems
Observations of
field inspector,
resource
reviewer, or
resident
1 Site Boundary Property line N/A 0 None None N/A
2 Creek Existing Greenes Creek 0.5 to 30% +/-100ft None Sedimentation,
ponding, flooding
No signs of major
sediment, ponding, or
flooding
3 Conveyance System Existing 24-inch bypass pipe 0.5 to 7% +/-500 ft None Under Capacity No capacity problems
were observed during site
visit
4 Creek Existing Greenes Creek 0.5 to 30% 500-4,150 ft None Sedimentation,
ponding, flooding
No signs of major
sediment, ponding, or
flooding
5 Creek Existing May Creek 0.5 to 30% +/-4,150 ft None Sedimentation,
ponding, flooding
No signs of major
sediment, ponding, or
flooding
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3.0 Preliminary Drainage Control Plan
The stormwater control plan for the site encompasses all available information about the site and
its downstream drainage system. This includes site topography, geology, detailed field
investigations, and drainage complaints and observations. Flow control and water quality treatment
BMPs have been evaluated. Preliminary evaluation of proposed flow control and water quality
facilities is provided in Section 4.0. A preliminary drainage plan is shown on Figure 6.
FLOW CONTROL STANDARD
This section is prepared in conformance with the requirements of the 2017 City of Renton Surface
Water Design Manual (COR SWDM) guidelines for drainage review and for downstream analysis
of a preliminary subdivision. The following describes the preliminary storm drainage design
approach of the stormwater control facilities for the project.
In order to comply with Core Requirement #3, this report follows Section 1.2.3. 2 Flow Control
Facility Implementation requirements. Based on findings in the soils report, full infiltration is not
feasible for the proposed development. The 2017 Manual requires use of extended period of record
continuous models such as WWHM, HSPF, MGS Flood, or other. The standard requires that post-
developed discharges match pre-development continuous flow durations between 50% of the 2-
year level through the full 50-year level and match the 2-year and 10-year peak. The facility was
sized to provide flow control for the site which included assumed impervious areas for future homes
and driveways up to the maximum impervious area allowed per zoning.
WATER QUALITY STANDARD
The Basic Water Quality treatment for the proposed development is to be provided through the
proposed water quality control facility within the proposed stormwater tract. The stormwater system
was designed to treat runoff through a cartridge system within a manhole before discharging
stormwater to the proposed detention facility. Calculations for WQ include assumed impervious
areas for the development of the project at hand. Assumed PGIS areas include the proposed road
and driveways for the five proposed lots.
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4.0 Flow Control and Water Quality Facility Analysis
The following is the preliminary analysis and design of the proposed stormwater flow control and
water quality facility for the Dalpay preliminary plat. These facilities have been designed to ensure
that any adverse impacts from the proposed development on downstream systems are prevented.
Part A. Existing Site Hydrology
The parcel is currently undeveloped and is vegetated with tall grasses, dense blackberry brambles,
and scattered stands of young deciduous trees along portions of the perimeter of the parcel.
General site topography of the property generally slopes towards the northwest and west. The
project site consists of moderate slopes ranging from 8 to 15 percent, draining into the existing
creek. Greenes Creek flows to the north and is located west of the property. As mentioned, in task
4 of Section 2 of this report, stormwater runoff flows north through Greenes Creek and a series of
existing pipes before discharging into May Creek.
Per the Flow Control Applications Map provided by the City of Renton, the project is located within
a Flow Control Duration Standard area. The 2017 COR SWDM requires projects located in this area
to assume a forested historical site condition for the existing site conditions. These assumptions
have been used for calculating allowable release rates and flow durations for the existing
stormwater control facilities. Existing site hydrology has been modeled using the approved
continuous model (MGS Flood).
NCRS soils mapping indicates that the site is underlain by Alderwood gravelly sandy loam (AgD).
SCS Group C till soils (See Figure 3). Per the Geotechnical Report, the soils observed in the test
pits are considered suitable for foundation support but not favorable for infiltration of site stormwater.
See Appendix B for more information.
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Level 1 Downstream Analysis and Preliminary Drainage Control Plan
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Part B. Developed Site Hydrology
The stormwater design has been developed to mitigate changes in stormwater runoff from the
proposed short plat. Per Section 1.2.3 of the 2017 COR SWDM, the project is required to match
developed discharge durations to predeveloped durations for the range of predeveloped discharge
rates from 50% of the 2-year peak flow up to the full 50-year peak flow and match peak rates for
the 2-year and 10-year return periods. Developed conditions in the MGS Flood model were updated
to meet Flow Control Duration Standards, matching Forested Historical site conditions within this
project. The total impervious areas for the new project include the proposed road, curb, gutter,
sidewalk, driveways, and assumed roof areas per the maximum allowed impervious area per
zoning. The maximum allowed impervious area per code is 50% of the proposed lots or 4,000 SF
(whichever is less). These assumed areas were used to model the flow control and water quality
facilities for the project.
To meet Core Requirement #8, a stormwater cartridge system is proposed for treatment of on-site
PGIS areas. Pollution-generating impervious surfaces will be treated before discharging runoff to
the proposed stormwater detention vault. The location of the proposed facilities is shown on
Figure 6.
Part C. Performance Standards
Flow Control BMPs
The proposed project is required to meet the flow control duration standard matching forested
historical site conditions per the 2017 COR SWDM. The proposed flow control facilities were
evaluated per current code requirements using an approved continuous model.
Water Quality Standard
Proposed water quality facilities were designed to mitigate for future development of this site. The
basic water quality facilities were examined using the current City of Renton Surface Water Design
Manual to meet basic water quality treatment.
SF AC
18,900 0.434
20,000 0.459
38,900 0.893
68,693 1.577
107,593 2.470
Developed Conditions
Road
Lot (4,000sf per lot)
Total Impervious
Total Pervious
Total Site
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Part D. Flow Control System
The following provides information related to the proposed flow control facility designed for the
development of this site. As previously mentioned, per the requirements set forth by the 2017 COR
SWDM, the project will meet flow control duration standards matching historic forested conditions.
The vault and flow control structure were designed using MGS Flood, meeting peak rates described
in Section 1.2.3 of the surface water design manual. Calculations for the facilities has been included
at the end of this report. Post developed runoff will continue to discharge runoff to the existing
Greenes Creek via a dispersion trench as shown in Figure 6.
Part E. Water Quality System
As noted above, basic water quality treatment for the site is provided by the proposed drainage
facilities within the proposed stormwater tract. The facilities were evaluated using the 2017 COR
SWDM and the approved continuous model. As previously mentioned, the facilities were designed
to include assumed impervious areas for future development of the site. The MGS Flood
calculations show that the proposed stormwater cartridges meet the requirements for water quality
treatment.
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————————————————————————————————
MGS FLOOD
DALPAY FLOW CONTROL & WQ PROJECT REPORT
Program Version: MGSFlood 4.46
Program License Number: 201810008
Project Simulation Performed on: 05/02/2019 3:44 PM
Report Generation Date: 05/02/2019 3:44 PM
—————————————————————————————————
Input File Name: Flow Control & WQ.fld
Project Name: Dalpay Short Plat
Analysis Title: Flow Control Matching Forested Historic Conditions
Comments: Lot size = 2.47ac
Impervious = 0.893 ac
———————————————— PRECIPITATION INPUT ————————————————
Computational Time Step (Minutes): 15
Extended Precipitation Time Series Selected
Climatic Region Number: 16
Full Period of Record Available used for Routing
Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097
Evaporation Station : 961044 Puget East 44 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) 2.470 2.470
Area of Links that Include Precip/Evap (acres) 0.000 0.000
Total (acres) 2.470 2.470
----------------------SCENARIO: PREDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Forest 2.384
Impervious 0.086
----------------------------------------------
Subbasin Total 2.470
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----------------------SCENARIO: POSTDEVELOPED
Number of Subbasins: 1
---------- Subbasin : Subbasin 1 ----------
-------Area (Acres) --------
Till Forest 1.577
Impervious 0.893
----------------------------------------------
Subbasin Total 2.470
************************* LINK DATA *******************************
----------------------SCENARIO: PREDEVELOPED
Number of Links: 0
************************* LINK DATA *******************************
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
------------------------------------------
Link Name: New Structure Lnk1
Link Type: Structure
Downstream Link: None
Prismatic Pond Option Used
Pond Floor Elevation (ft) : 100.00
Riser Crest Elevation (ft) : 105.00
Max Pond Elevation (ft) : 105.50
Storage Depth (ft) : 5.00
Pond Bottom Length (ft) : 80.0
Pond Bottom Width (ft) : 40.0
Pond Side Slopes (ft/ft) : L1= 0.00 L2= 0.00 W1= 0.00 W2= 0.00
Bottom Area (sq-ft) : 3200.
Area at Riser Crest El (sq-ft) : 3,200.
(acres) : 0.073
Volume at Riser Crest (cu-ft) : 16,000.
(ac-ft) : 0.367
Area at Max Elevation (sq-ft) : 3200.
(acres) : 0.073
Vol at Max Elevation (cu-ft) : 17,600.
(ac-ft) : 0.404
Massmann Infiltration Option Used
Hydraulic Conductivity (in/hr) : 0.00
Depth to Water Table (ft) : 100.00
Bio-Fouling Potential : Low
Maintenance : Average or Better
Riser Geometry
Riser Structure Type : Circular
Dalpay Preliminary Short Plat June 2019
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Riser Diameter (in) : 18.00
Common Length (ft) : 0.010
Riser Crest Elevation : 105.00 ft
Hydraulic Structure Geometry
Number of Devices: 2
---Device Number 1 ---
Device Type : Circular Orifice
Control Elevation (ft) : 100.00
Diameter (in) : 1.00
Orientation : Horizontal
Elbow : No
--- Device Number 2 ---
Device Type : Vertical Rectangular Orifice
Control Elevation (ft) : 102.30
Length (in) : 0.13
Height (in) : 32.00
Orientation : Vertical
Elbow : No
**********************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: New Structure Lnk1 ********** Link WSEL Stats
WSEL Frequency Data(ft)
(Recurrence Interval Computed Using Gringorten Plotting Position)
Tr (yrs) WSEL Peak (ft)
======================================
1.05-Year 101.145
1.11-Year 101.309
1.25-Year 101.615
2.00-Year 102.353
3.33-Year 102.719
5-Year 103.093
10-Year 103.808
25-Year 104.414
50-Year 104.506
100-Year 104.778
***********Water Quality Facility Data *************
----------------------SCENARIO: PREDEVELOPED
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Number of Links: 0
----------------------SCENARIO: POSTDEVELOPED
Number of Links: 1
********** Link: New Structure Lnk1 **********
Basic Wet Pond Volume (91% Exceedance): 5692. cu-ft
Computed Large Wet Pond Volume, 1.5*Basic Volume: 8538. cu-ft
Infiltration/Filtration Statistics--------------------
Inflow Volume (ac-ft): 640.21
Inflow Volume Including PPT-Evap (ac-ft): 640.21
Total Runoff Infiltrated (ac-ft): 0.00, 0.00%
Total Runoff Filtered (ac-ft): 0.00, 0.00%
Primary Outflow To Downstream System (ac-ft): 640.19
Secondary Outflow To Downstream System (ac-ft): 0.00
Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00%
***********Compliance Point Results *************
Scenario Predeveloped Compliance Subbasin: Subbasin 1
Scenario Postdeveloped Compliance Link: New Structure Lnk1
*** 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 7.969E-02 2-Year 4.128E-02
5-Year 0.130 5-Year 6.653E-02
10-Year 0.163 10-Year 0.103
25-Year 0.214 25-Year 0.141
50-Year 0.273 50-Year 0.148
100-Year 0.295 100-Year 0.167
200-Year 0.441 200-Year 0.170
** 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%): -30.9% PASS
Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): -26.8% PASS
Maximum Excursion from Q2 to Q50 (Must be less than 10%): -10.0% PASS
Percent Excursion from Q2 to Q50 (Must be less than 50%): 0.0% PASS
-------------------------------------------------------------------------------------------------
MEETS ALL FLOW DURATION DESIGN CRITERIA: PASS
Figures
Vicinity Map
No Address Assigned
Tax Parcel 0323059120
FIGURE 1
North
Not to Scale
Site
Pictom etr y, Ki ng C ou n ty, K ing C ou nty
Date : 11 /1 2/2 018 Notes:
±The informati on included on this map has been compi led by King County staff from a variety of sour ces and issubject to change wi thout notice. King County makes no r epresentati ons or w ar ranties, expr ess or impl ied,as to accurac y, completenes s, timeli ness , or ri ghts to the use of such infor mation. This document is not intendedfor use as a s urvey pr oduct. King County shall not be liable for any gener al, s pecial, i ndir ect, incidental , orconsequential damages incl uding, but not li mited to, lost revenues or lost pr ofits resulting fr om the use or misuseof the information contained on this map. Any sale of this map or infor mati on on this map is pr ohibited except bywritten per mi ssi on of Ki ng County.
FIGU RE 2 SITE AER IAL
9
Custom Soil Resource Report
Soil Map
526161052616305261650526167052616905261710526173052617505261770526179052618105261830526161052616305261650526167052616905261710526173052617505261770526179052618105261830564360 564380 564400 564420 564440 564460 564480 564500 564520
564360 564380 564400 564420 564440 564460 564480 564500 564520
47° 30' 24'' N 122° 8' 43'' W47° 30' 24'' N122° 8' 35'' W47° 30' 16'' N
122° 8' 43'' W47° 30' 16'' N
122° 8' 35'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84
0 50 100 200 300
Feet
0 15 30 60 90
Meters
Map Scale: 1:1,120 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: King County Area, Washington
Survey Area Data: Version 14, Sep 10, 2018
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 8, 2014—Jul 15,
2014
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
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Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
AgC Alderwood gravelly sandy loam,
8 to 15 percent slopes
3.6 100.0%
Totals for Area of Interest 3.6 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into landforms or
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
Custom Soil Resource Report
11
9,0281505
City of Renton Print map Template
This map is a user generated static output from an Internet mapping site and
is for reference only. Data layers that appear on this map may or may not be
accurate, current, or otherwise reliable.
THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere
Notes
Downstream Analysis
06/05/2019
Legend
1023 0 512 1023 Feet
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
Environment Designations
Natural
Shoreline High Intensity
Shoreline Isolated High Intensity
Shoreline Residential
Urban Conservancy
Jurisdictions
Streams (Classified)
<all other values>
Type S Shoreline
Type F Fish
Type Np Non-Fish
Type Ns Non-Fish Seasonal
Unclassified
Not Visited
Wetlands
Pump Stations
Discharge Points
Stormwater Mains
Culverts
Open Drains
Facility Outlines
Private Pump Stations
Private Discharge Points
Private Pipes
Private Culverts
Private Open Drains
Private Facility Outlines
Streets
Parks
Waterbodies
Map
Extent2010
N87°49'06"W 380.03N16°29'59"W 433.63N56°37
'22
"E
300
.25
S1°25'23"W 236.20 WWWWWWWWSD SD SD SD SDGGGGGGGGGGGGGGGGGGGGGGGGEEEEEEEE
E E
E
E E E E E E
ETTT
TTTT
TTTT
T T T T T T T T T T
T T T T T T T
SSSSSSSSSSSSSSSSSSSSSSSSSSXXXXXXXXXXXXXXXXXXXXXXW W W W WSSSSSSSSGGGGG G
WWGG G
GGGGG WWWSSTTSS615
5
.
0
'542110,348 SF9,534 SF13,459 SF13,160 SF15,012 SFTRACT A(CRITICAL AREA)TRACT BRIGHT
-OF
-WAY
DED
ICAT
ION
AREA
=
9
,117
SF21'21'7,879 SFTRACT B(STORM DETENTION)42' R.O.W.SECTION A-AMOUNT BAKER PL. NEN.T.S.15.5'DRIVINGLANE5' SIDEWALKVERTICAL CONCRETECURB AND GUTTER, TYP.2%±2%0.5' CURB2%±2%15.5'DRIVINGLANE5' SIDEWALK0.5' CURBDRAWN:APPROVED:PLOTTED:DESIGNED:L:\2018\18067\3 DEVELOPMENT\CAD\HOST DRAWINGS\PRELIM SHORT PLAT\18067P01.DWG2019/06/03 09:15ClatorreSHEETSE 1/4, SE 1/4 SECTION 3, TOWNSHIP 23 N, RANGE 5 E, W.M.CITY OF RENTON, KING COUNTY, WASHINGTONCLTCLTKJGDALPAY PROPERTIESJOB NO. 18067CITY OF RENTONKING COUNTYWASHINGTONHGGEXH5H.dwt BGOLDS 10/21/14 08:42S:\DWTs\Shared Printers\TitleBlocks\HGG Standard\HGGEXH5H.dwt
FORDALPAY PRELIMINARY SHORT PLATPRELIMINARY GRADING, UTILITIES, AND DRAINAGE PLAN090601530SCALE: 1" = 30'SE REN
TON
-
ISSAQUAH
ROAD
148TH AVENUE SE
MOUNT BAKER PL. NE
Know what'sbelow.before you dig.CallR8" SS45 LF72 LF
12" SDAASANITARY SEWERCONNECTION, TYP.WATER METER, TYP.STORMWATER WQTREATMENT CARTRIDGESYSTEM 72" MHTYPE I CB, TYP.ROOF/YARD DRAINCONNECTION, TYP.STORMWATER DETENTION FACILITYREQUIRED VOLUME = 16,000 CU.FT.TOP OF LID ELEV. = 428.0INSIDE OF LID ELEV. = 427.0OUTLET IE = ±422.0CONNECT TO EXISTINGSANITARY SEWERIE = XXX.XX8" WMPROPOSED MAJOR 10' CONTOUR430SDSSWPROPOSED SANITARY SEWER PIPELEGENDSPROPOSED WATER MAINDWPROPOSED SIDEWALKPROPOSED ASPHALT PAVEMENTPROPOSED CB TYPE IIPROPOSED SANITARY SEWER MHPROPOSED CB TYPE IPROPOSED STORM PIPEPROPOSED MINOR 2' CONTOUR42820'3
0
'20'FLOW CONTROLFACILITYDISPERSION TRENCHGROUND ELEV. = ±422.018067P01.dwg clator 06/03/19 09:15L:\2018\18067\3 DEVELOPMENT\CAD\HOST DRAWINGS\Prelim Short Plat\18067P01.dwg
PROPOSED BSBL3
0
'20'3
0
'20'30'20'5'15.4
'5'BSBL
BSBLBSBLBSBL
R30.5
'PROP. FIRE HYDRANT
4,514752
City of Renton Print map Template
This map is a user generated static output from an Internet mapping site and
is for reference only. Data layers that appear on this map may or may not be
accurate, current, or otherwise reliable.
THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere
Notes
None
06/06/2019
Legend
512 0 256 512 Feet
Information Technology - GIS
RentonMapSupport@Rentonwa.gov
Erosion Hazard - High
Landslide
Very High
High
Moderate
Unclassified
Slope City of Renton
>15% & <=25%
>25% & <=40% (Sensitive)
>40% & <=90% (Protected)
>90% (Protected)
Environment Designations
Natural
Shoreline High Intensity
Shoreline Isolated High Intensity
Shoreline Residential
Urban Conservancy
Jurisdictions
Streams (Classified)
<all other values>
Type S Shoreline
Type F Fish
Type Np Non-Fish
Type Ns Non-Fish Seasonal
Unclassified
Not Visited
Wetlands
Seismic Hazard Areas
Faults
Streets
Points of Interest
Parks
Waterbodies
Map
Extent2010
Appendix A
King County Water & Land Resources
Division Drainage Complaint
Investigation Sheets
King County Water and Land Resources Division - Drainage Services Section
Complaint Search Printed : 5/9/2019 1:24:00 PM
Number Type Type of Problem Address of Problem Comments Tbros Page
Complaint Type Code Type of Problem Address of Problem Comments
2009-0008 R RFD 10415 147TH AVE SE INQUIRY FROM MS. DONNELLY ABOUT 626J5
2009-0250 NDA- RFD 10269 147TH AVE SE SURCHARGING CB ERODES DRIVEWAY. 626J5
2009-0250 R RFD 10269 147TH AVE SE SURCHARGING CB ERODES DRIVEWAY. 626J5
2010-0374 C DDM 148TH AVE SE - SE May Valley flooding? Inv did not find any 626J5
2010-0714 C RFD 10269 14TH AVE SE Yard/house flooding from storm? Inv found 626J5
2010-0714 R RFD 10269 14TH AVE SE Yard/house flooding from storm? Inv found 626J5
2011-0722 X INQ 5625 NE 26TH ST EMAIL CONCERNING ROADSIDE DITCH 626J5
2012-0676 WQC DES LYONS AVE NE Dirt from new development on road? Project 626J6
2013-0760 WQC WQDR 2701 Nile Ave NE Tires in wetlands 626J5
2014-0152 I INQ 10415 147TH AVE SE EMAIL INQUIRY ABOUT POTENTIAL 626J5
2014-0245 X DDM 10415 147th AVE SE INQUIRY ABOUT A PROJECT IN THE CITY 626J5
2014-0500 C MFD 10217 148th Ave SE Dumping in ditch? 626J5
2015-0293 NDA- DES 10415 147th Ave SE ACTUALLY TURNED TO NDA-Q ON 3/23/15. 626J5
2015-0293 R DES 10415 147th Ave SE 626J5
2015-0321 WQC WQO 10274 147TH AVE SE Collapsing railroad ties near stormwater ditch. 626J5
2015-0631 C DES 10415 147th Ave SE Concern about roadside ditch maintenance. 626J5
2015-0863 C RFD 10202 148TH AVE SE Ditch water is crossing the driveway and 626J5
2015-0863 R RFD 10202 148TH AVE SE Ditch water is crossing the driveway and 626J5
2016-0556 C INQ 9846 148TH AVE SE Unpermitted septic and earth moving 626J5
2017-0621 WQC WQDR 10217 148TH AVE SE Litter in the culvert draining into Greens Creek 626J5
2017-0725 X INQ 10415 147th Ave SE Several emails received by several staff 626J5
2018-0003 WQC WQO 10201 148th Ave SE water coming over the side of the bank into 626J5
2018-0282 R DES 10202 148th Ave SE Erosion in R-O-W due to runoff from private 626J5
2019-0075 C RFD 10415 147th Ave SE Concern about Greenes Stream. Complaint 626J5
2019-0078 R SKH 10218 148th Ave SE Sinkhole 37' x 14' x "a couple" feet deep. 626J5
Appendix B
Geotechnical Report by Associated
Earth Sciences, Inc. – April 19, 2019