HomeMy WebLinkAboutMiscDRAFT
TECHNICAL INFORMATION REPORT
for
WONDERLAND ESTATES
RENTON, WASHINGTON
April 9, 2010
Prepared for:
King County Housing Authority
600 Andover Park West
Tukwila, WA 98188
Contact: Hugh Watkinson
(206) 574-1230
Email: hughw@kcha.org
Prepared by:
HUITT-ZOLLARS, INC.
814 East Pike Street
Seattle, Washington 98122
Contact: Don Helling, PE
(206) 324-5500
Hllrn---zc)Lli\RS
HUITT-ZOLLARS, INC. • 814 E. Pike Street • Seattle, WA 98122-3893 • 206.324.5500 phone • 2oti.:m.1aao fax • huitt-zoHars.com
Table of Contents
TECHNICAL INFORMATION REPORT
Section I -Project Overview
Section 2 -Conditions and Requirements Summary
Section 3 -Offsite Analysis
Section 4 -Retention/Detention Analysis and Design
Section 5 -Conveyance System Analysis and Design
Section 6 -Special Reports and Studies
Section 7 -Basin and Community Planning Areas
Section 8 -Other Permits
Section 9 -CSWPPP Analysis and Design
Section IO -Bond Quantities, Facility Summaries, and Declaration of
Covenant
Section 11 -Operations and Maintenance Manual
References
FIGURES
Figure I
Figure 2
Figure 3a
Figure 3b
Figure4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
TIR Worksheet (2 pages total)
Site Location Map
General Site Drainage Map -Existing Conditions
Regional Drainage Map
Flood Map
Drainage Complaint Map
Landslide Hazard Area Map
Soil Map (3 pages total)
Off-Site Analysis Limits
Off-Site Analysis Details
J:\15093201 \Wonderland Estates\06\AprilTIR
IA? ~J (C ll1f 1Wi[€ [[))
Page2
Page 5
Page 14
Page 15
Page 15
Page 15
Page 15
Page 15
Page 17
Page 17
Page 18
DRAFT 4/91201(1
HL!ITT --2r )LL%
HUITT-ZOLLARS. INC 814 E. Pike Street • Seattle. WA 98122-3893 • 206.324.5500 phor,e • 206.326.1880 lax • huitt-zoHars.com
Figure 10
Figure 11
Figure 12
Site Hydrology
Preliminary Drainage System Schematics
Preliminary Drainage System Details
APPENDICES
Appendix A
Appendix B
Appendix C
Appendix D
Offsite Analysis Supporting Documentation
Runoff Calculations
Conveyance Calculations and Supporting Documents
Alternative Drainage Proposal
J:\ I 509320 I\ Wonderland Estates\06\Apri!TIR 11 DRAFT 4/9/201fl
H LJITr~zc)LlAPS
HUlffZOLLARS, INC. • a14 E. Pike Street • Seattle. WA 98122-3893 , 206.324.5500 phone • 206.320.1880 fax • huitt-z~lars.com
SECTION 1 PROJECT OVERVIEW
This Technical Information Report (TIR) describes the stormwater management facilities
for the Wonderland Estates (WE) project. This report has been prepared in conformance
with City of Renton codes and the 1990 King County Surface Water Design Manual (see
Figure 1-TIR Worksheet, for project summary information).
The project site is located at 14645 SE Renton-Maple Valley Road (SR 169) in Renton,
Washington (Figure 2). The project site surface area is approximately 12.2 acre (531,800
square feet). This lot has been developed as a mobile home park since 1960.
This project proposes replacing existing utilities (storm drain, sanitary sewer, water,
electrical) and replacing existing asphalt roadways. The project will create no net
increase in impervious surface. A net reduction in impervious surfaces will result from
narrowing the roads and removing an obsolete tennis court.
EXISTING CONDITIONS
As shown in the general site drainage map (Figure 3a), on-site stormwater generally
flows south to north/northwest toward SR-169 and the northwest corner of the site.
Altered topography due to construction of SR-169 to the north and Pioneer Place to the
west has resulted in the need to pump runoff from the site. Watercourses in the area
include Madsen Creek, a bypass channel of Madsen Creek, and a roadside ditch/swale
system that conveys road runoff and site drainage to the west along the south side of
SRl69. Figure 3b shows the regional drainage system and the relation of the site to the
various watercourses.
Madsen Creek is a Class 2 salmon-bearing stream that parallels the northeast edge of the
site before crossing under SR-169 to the north in a culvert near ( east of) the site entrance
road.
The Madsen Creek bypass channel flows to the north along the east site boundary. It
diverts high flows by means of control structures located in the King County detention
pond located near the southeast corner of the site.
The roadside swale system (with a few driveway/entrance culverts) continues to the west
for about 1,500 feet before discharging into an intermittent watercourse tentatively
identified as a Class 4 stream (called "Stream A" in this report). All three watercourses
discharge to the Cedar River.
The natural drainage patterns appear to have been significantly altered, especially by the
construction of SR-169. The natural location for drainage under current conditions
appears to be offsite to the swale system to the west along SR-169. However, the flow
capacity of this swale system has been compromised by construction of frontage
improvements associated with Pioneer Place.
The exsting on-site drainage system collects storm water runoff by gravity flow in a pipe
network and pumps low flows to Madsen Creek at the two locations shown on Figure 3a.
During high runoff events, the two pumps (capacity 0.3 cfs each) are incapable of
matching peak runoff rates and runoff ponds in the northwest portion of the site before
J:\15093201 \ Wonderland Estates\06\AprilTIR 1 DRAFT 419/2011
HLHTT--ZC)LL'\1\S --------
HUITI-ZOLLARS. INC. • 814 E Pike Street • Seattle, WA 98122-l893 • 206.324.5500 phone • 206.326.1880 fax • hwtHollars.com
discharging to the swale system to the west. The combined pumping capacity of 0.6 cfs
is less than half the 2-year peak runoff from the site (see Section 4 for hydrology
computations). The condition of the roadside swale at the northwest comer prevents
efficient discharge at this location, and runoff floods onto the adjacent property (Pioneer
Place), where homes are impacted before runoff enters the development's drainage
system.
Madsen Creek floods onto the site at the location of the current pump discharges,
impacting roads and some of the structures in the north end of the site, and Pioneer Place
adjacent to the site. Madsen Creek flooding at this location is most likely caused by
reduction in channel conveyance capacity due to sedimentation in the channel, which has
resulted in the partial blocking of the box culvert under SR-169 and a culvert under 1491
h
Avenue SE downstream of the site. During Madsen Creek flooding, pumping to Madsen
Creek results in re-circulation of site runoff back onto the site.
PROPOSED CONDITIONS
The project proposes to maintain the current drainage configuration of pumping to
Madsen Creek, with higher flows continuing to discharge to the swale leading to Stream
A.
Regrading in the northwest comer of the site will be used to create flood storage volume
and reduce the potential of flooding on-site structures. The onsite flow characteristics of
the existing site would not be altered, except for replacing sheet flow with pipe flow over
a short distance.
The previous March 16, 2010 draft of the TIR proposed discharging all site runoff to the
swale system and eliminating the pumped discharge of low flows to Madsen Creek. This
alternative approach was not approved by the City. Appendix D contains a copy of the
City's "On-Hold Notice" for that alternative proposal, and a copy of the Huitt-Zollars
response to the issues raised in the On-Hold Notice.
SECTION2
CONDITIONS AND REQUIREMENTS SUMMARY
The project is located adjacent to Madsen Creek, which is classified as a Class 2 stream
on City ofRenton's Critical Areas Maps. The project is therefore subject to drainage
review with applicable requirements as summarized below:
Core Requirement 1: Discharge at Natural Location
As described above, the natural discharge location is ambiguous, due to the alteration of
the drainage pattern, especially due to the construction of SR 169, which presents a
hydraulic barrier for all runoff and stream flow from the area south of the road. The
project will maintain the current discharge location and pumping rates.
J:\15093201 \ Wonderland Estates\06\AprilTIR 2 DRAFT 4/9/201D
HUITT-ZOLLARS. INC. • 814 E. Pike Street • Seattle, WA 981n-38S3 206.324.5500 phone • 206.328.1880 !ax • huitt-zollars.com
Core Requirement 2: Offeite Analysis
Level I Offsite Analysis has been performed as required and is documented in Section 3
below.
Core Requirement 3: Runof!Control
The parcel is in the category of"No Existing Approved Drainage System." Therefore,
"existing conditions" for purposes of drainage analysis and design are defined as those
pertaining prior to May 1979. The parcel was developed to its approximate current
condition in the 1960s.
Peak rate control is not required because the project proposes less than 5,000 square feet
( sf) of new impervious surface.
Biofiltration or other runoff treatment is not required because the project does not create
more than 5,000 sf of new impervious surface.
Core Requirement 4: Conveyance System
All standards from the KC SWDM apply.
The project is seeking a variance to allow a pump system with a smaller storage capacity
than 25% of the 2-year, 24-hour runoff. The reasons for this request are as follows:
• The existing conditions use a pump system, without such storage;
• Due to drainage alterations by others (e.g., SR-169), discharge to Madsen Creek is
not possible without pumping;
• The requirement would result in a large, expensive storage structure (it would
need to be underground) that would not provide additional downstream flooding
protection over the proposed structure;
• Overflow from the proposed system (in the hypothetical event of pump failure)
will be conveyed in the swale system without inundating or overtopping any road,
or flooding any part of a building.
Core Requirement 5: Erosion and Sediment Control
All standards from the KC SWDM apply. Section 8 describes how the TESC and
CSWPPP plans meet these standards.
Core Requirement 6: Maintenance and Operations
O&M manuals are provided (Section 11) for all stormwater facilities.
J:\ 1509320 I\ Wonderhmd Estates\06\AprilTIR 3 DRAFT 4/9/20171
1-ILllJT--z{JLIAI~
HUITT-ZOLLARS, INC. • 814 E. Pike Street • Seattle, WA %122-3893 206.324.5500 phone 206.328.1&10 f~ • huitt-zollars.com
Core Requirement 7: Bonds and Liability
To be determined:
Special Requirement I: Critical Drainage Areas
The King County parcel maps, Figures 4, 5 and 6 indicate the following:
• A portion of the parcel is located within the mapped JOO-year floodplain the
Cedar River. The strip of floodplain is associated with Madsen Creek as it flows
west adjacent to SR-169. The parcel is outside the floodway.
• The parcel is shown as being in a "moderate" drainage complaint area.
• The parcel is outside shoreline jurisdiction.
• Madsen Creek adjacent to the parcel is a Class 2 salmonid stream per the SAO
• The southern portion of the site is mapped in a Landslide Hazard Area as defined
by the KC SWDM
Special Requirement 2: Compliance with an Existing Master Drainage Plan
Not applicable.
Special Requirement 3: Conditions Requiring a Master Drainage Plan
Not applicable.
Special Requirement 4: Adopted Basin or Community Plans
The Lower Cedar River Watershed Plan contains no additional area-specific requirements
beyond those contained in Renton Code and the KC SWDM.
Special Requirement 5: Water Quality Controls
The proposed new impervious surfaces are less than 5,000 square feet; therefore water
quality treatment is not required.
Special Requirement 6: Coalescing Plate Oil/Water Separators
The proposed impervious surface is less than 5 acres; therefore oil/water separation is not
required.
Special Requirement 7: Closed Depressions
The project does not discharge to a closed depression; this special requirement does not
apply.
J :\1509320 I\ Wonderland Estates\06\Apri!TIR 4 DRAFT 4!9/20JIJ
HlJITT-ZC)LLAI<S ·------------
HUITT.ZOLLARS.INC. • 814E.PikeStreet • Seattlf!,WA 98122-3893 206.J24.5500phone • 206.328.1880fax • hu1tt-zollc1"s.com
Special Requirement 8: Use of Lakes, Wetlands or Closed Depressions for Peak Rate
Control
This requirement does not apply to this project.
Special Requirement 9: Delineation of JOO-Year Floodplain
This project does not propose development or encroachment in the 100-year floodplain,
as mapped by King County (see Figure 4). Delineation of the JOO-year floodplain is not
required.
Special Requirement IO: Flood Protection Facilities for Type I and 2 Streams
No flood protection facilities are required or proposed.
Other Adopted Area-Specific Requirements -None Identified.
Special Requirement 11: Geotechnical Analysis and Report.
None required.
Special Requirement 12: Soils Analysis and Report:
None required. Soils are as mapped in Figure 7 and described in Section 4 below.
Special Requirement 13: Aquifer Protection and Recharge Areas
The parcel is in a Category I Aquifer Recharge Area. No discharges to groundwater are
proposed.
SECTI0N3
OFFSITE ANALYSIS
As determined by the City during pre-permit application discussions, a Level I Offsite
Analysis is required.
The following resources were reviewed/consulted as part of the Level 1 Offsite Analysis:
• County critical and sensitive area maps
• FEMA and County floodplain maps
• County drainage complaint maps
• Available drainage reports
J:\1509320 I\ Wonderland Estates\06\Apri!TIR 5 DRAFT 419/2018
1--l llllT-.zr )LLAJ{S -----------------------HUITT-ZOLLARS, INC. • 814 E. Pike Street • Seattle, WA 98122-3893 • 2D6.324.5500 phone • 206.32& 1eeo lax • hurtt-zol!ars.com
Field inspections were perfonned on Sunday, December 20, 2009 and Monday December
28, 2009 by Chuck Manning, PE of Huitt-Zollars. Appendix A.2 contains representative
photos taken during the field inspection. Infonnation (photographs and field survey) by
Huitt-Zollars personnel was also used in the analysis. The Offsite Analysis Drainage
System Table (Appendix A.I) was prepared on the basis of the resources review and the
field inspections.
Figure 8 shows the extent of the study area and location(s) of some of the illustrative
photographs. Figure 9 shows the locations of drainage issues identified in Appendix A.1
and of the remainder of the photos referenced in this report. The photos in Appendix
A.3, taken over a series of dates beginning in January 2009, are included to illustrate
offsite and on-site drainage conditions, during both low flow and high flow conditions.
The offsite analysis encompasses the upstream tributary area and two downstream
conveyance systems, as described below.
Upstream Tributary Area
It appears that little offsite runoff drains onto the Wonderland Estates site, as illustrated
in the study area map (Figure 8). A small portion of the steep, forested hill to the south
drains toward the site. This area is heavily forested and produces little runoff. A small
"duck" pond located near the southern site boundary receives runoff from the small
offsite area, and from a seepage interceptor trench located along the base of the steep
slope. Photos I and 2 in Appendix A.2 illustrate the offsite area and the duck pond.
A significant feature affecting flow in Madsen Creek through the site is the King County
detention pond on Madsen Creek located near the southeast corner of the site (see Figure
3). The pond traps sediment and diverts high flows to the Madsen Creek high-flow
bypass channel. The pond and outlet control/diversion structures are illustrated in Photos
3-8 in Appendix A.2. Lower flows are discharged from the pond from 42-and 24-inch
diameter CMP culverts (Photos 5-6). The larger culvert has been fit with a control plate
over the top 1.5 feet of its diameter. The bypass weir structure elevation is such that
overflow will begin to occur when the water surface is at a depth of 34 inches on the 42-
inch culvert, or about 4 inches over the top of the culvert opening.
Photos 9-13 illustrate conditions in the bypass channel downstream of the sediment pond.
There are no apparent flow constrictions in this channel. The project does not propose to
discharge to this channel. There is, however, apparent capacity in this channel.
Under current drainage conditions, stonn water runoff is pumped to Madsen Creek at the
locations shown on Figure 3. When Madsen Creek is flooding, due to conditions in the
rest of the basin, the pumped stonnwater from Wonderland Estates adds to the flooding
condition. Runoff accumulates on the property until a sufficient elevation is attained, at
which point it exits the property at the northwest corner of the property via a ditch
flowing to the west along SR -169. Two downstream flow routes are therefore described
in this analysis: Madsen Creek and the SR-169 swale system.
J :\15093201 \ Wonderland Estates\06\AprilTIR 6 DRAFT 4/9/ZOJ(J
1-i LJ 111--.zL)LLARS
HUITT-ZOLLARS, INC. • 814 E. Pike Street • SeatUe. WA 98122-3893 • 206.324.5500 phone • 206.328. 1880 rax • hUlH·zollars.com
Downstream Analysis
Two drainage courses receive runoff from the site: Madsen Creek as it parallels the
northeast site boundary between the site and SR-169, and the roadside ditch/swale system
that conveys road runoff to Stream A to the west along the south side of SR-169. Both
systems receive runoff from the site under existing conditions. The project proposes to
maintain existing discharge rates and volumes to each system. The two drainage courses
are described below. Both ultimately discharge to the Cedar River.
Lower Madsen Creek
Despite the flow control provided for Lower Madsen Creek by the high flow bypass
system described above, Madsen Creek at and below Wonderland Estates continues to
experience flooding. Photos 14-20 illustrate conditions in Lower Madsen Creek adjacent
to Wonderland Estates. Under high flows such as those experienced in January 2009 (the
result of rainfall estimated to be between the 10-and 25-year recurrence interval event),
Madsen Creek floods onto the Wonderland Estates property. Water pumped into Madsen
Creek from the site cannot be accommodated by the channel at the site, and exacerbates
the flooding. Water builds up on the Wonderland Estates site until it reaches an elevation
at which it can follow the pathway to the west at the NW comer of the site. Because the
drainage of the swale system offsite at the northwest comer of the site has been altered
(by others), the swale system cannot accept the overflow and runoff flows into the NE
comer of Pioneer Place, threatening homes and adding flow to the Pioneer Place
detention system for which the system was not designed.
Photos 14-16 show Madsen Creek in high flow and dry conditions as it crosses under the
high flow bypass channel and enters the site. Photos 17-20 illustrate Madsen Creek as it
flows adjacent to the site and the inlet to the box culvert that conveys Madsen Creek
under SR-169. Figures 21-23 show the culvert under 149 1h Avenue SE that is submerged
even under lower flows when there is no flow in the bypass channel. Figure 24 shows
Madsen Creek from the bridge in the Regis Park access road. Flow appears to be
restricted by sediment buildup in the box culvert and in the Madsen Creek channel
downstream of the bridge over 149th Ave SE.
The following discussion describes each of the drainage elements identified in the Offsite
Analysis Drainage Table in Appendix A.I. It should be noted that Madsen Creek floods
under the existing drainage configuration, due to factors beyond the control of
Wonderland Estates.
Drainage Element Ml (see Photos 14-20, 25, 26)
Madsen Creek in the vicinity of Wonderland Estates is mapped in the 100-year floodplain
(Figure 4). Madsen Creek appears to flood primarily due to fine sediment buildup in the
channel downstream of the site, including the box culvert under SR-169 (see discussion
of M2, M3 and M4 below). During low flow conditions (when the Madsen Creek high
flow bypass is not flowing), the Creek appears as it does in Photos 15, 17 and 19, with a
J:\ 1509320 I\ Wonderland Estates\06\Apri!TIR 7 DRAFT 4191201'0
f--JLJITT-ZC)Ll.'\RS ---------HU I TI· ZOLLARS. INC. • 814 E. Pike Slreet • Seattle, WA 98122-3893 • 206.324.5500 phone • 206 328.1880 fa,. • hu1t1-zoHars.com
freeboard of about one foot before flooding onto Wonderland Estates starts. High flow
conditions are shown in Photos 14, 16, 18 and 20. As can be seen in Photo 14, the
headwall for the box culvert under the high flow bypass channel backs up water behind
the box culvert. The outlet to the box culvert is completely submerged (Photol6) as is
the entrance to the box culvert under SR-169 (Photo 20) under these conditions, probably
reflecting the translation of downstream restrictions upstream.
Figures 25-26 illustrate the aftermath of the January 2009 flooding in Wonderland
Estates.
Drainage Element M2 (see Photos 19-20)
The Madsen Creek culvert under SR-169 is an 8 feet by 6 feet (width by height) concrete
box culvert. Measurements at the upstream end of the culvert (location of photos),
indicated that the culvert opening is free of sediment. However, the downstream outlet of
the culvert is blocked within about two feet of the top of the culvert. Flow restriction due
to sedimentation in the lower channel, as the grade flattens north of SR-169, is the likely
cause. As noted in the Madsen Creek Tributary Erosion Stabilization Projects,
Biological Assessment (Adolphson Associates, 2001, prepared for King County
Department of Natural Resources) the sediment transport capacity of lower Madsen
Creek has changed due to operation of the high flow bypass channel. Cutting off the high
flows has resulted in the deposition of fine sediments (sand) not trapped by the detention
pond being deposited in the lower channel north of SR-169. These deposits result in
lower channel hydraulic capacity and backwater flooding in the vicinity of Wonderland
Estates.
Drainage Element M3 (see Photos 21-23)
M3 is a metal culvert conveying Madsen Creek under 149th Avenue SE north of SR-169.
The dimensions of the culvert are not known. The culvert as measured in the field is an
arch with a maximum depth of depth observed in the field (December 20, 2009) of 1.8
feet and a width of about 7 feet. As shown in the photos, even during low flow
conditions both the upstream and downstream ends of the culvert are submerged by about
0.5 feet (2.3 feet water depth).
Drainage Element M4 (see Photo 23)
The Madsen Creek channel immediately downstream of M3 is a uniform 9-feet wide
channel with a bottom of almost uniformly sized sand. The depth of flow IO feet
downstream from M3 on December 20, 2009 (low flow) was 0. 9 feet, 1.4 feet less than at
the bridge. The deposition below 149th Ave SE is the apparent cause of the submerged
conditions at M3.
J:\1509320 l\Wonderland Estates\06\ApritTIR 8 DRAFT 4/9/2019
HLHlT .Z()LIARS ·------------·---------·-
HUITI-ZOLLARS. INC. • 814 E. Pike Stree1 • Seattle, WA 96122-3893 • 206.324.5500 phone • 206.328. 1880 fax • hwtt-zolln.com
Drainage Element MS (see Photo 24)
The bridge over Madsen Creek as it passes under the access road to Ron Regis Park does
not appear to restrict flow. The flow opening under the bridge low chord is 15 feet wide.
There was 1.3 feet of clearance between the flow in the Creek on December 20, 2009 and
the bridge chord, when the flow depth was a maximum of 1.2 feet. Fine sandy sediments
characterize the creek bottom at this location as well.
In general, the condition of Madsen Creek in the vicinity of Wonderland Estates is such
that no type of onsite flow control at Wonderland Estates can alleviate either on-site or
downstream flooding. Based on this assessment, quantitative (backwater) analysis of the
flow conditions in lower Madsen Creek was not deemed useful and was not performed.
Drainage Element M6
Madsen Creek broadens and flows through a wetland complex paralleling the Cedar
River. The proposal will not affect flows to this wetland.
Drainage Element M7
This section of Madsen Creek is the channelized segment leading from the wetland to the
confluence with the Cedar River (confluence illustrated in Photos 41 and 42). Note that
the mouth is perched about 3 feet above the Cedar River water level ( observed March I 0,
2010). The Cedar River has eroded its left bank in this area since 2001 when the main
flow of the River was diverted to this old side channel following the 2001 earthquake-
induced slide that blocked the main channel. The old lower channel of Madsen Creek,
along with some Park trails, has been cut off, resulting in the mouth of the creek being
located further to the east than it was prior to 2001.
SR-169 Swale System
The SR-169 Swale conveys road runoff and some site runoff to the west, parallel to SR-
169 along the south side of SR-169, where it enters Stream A (probably a Class 4 stream)
coming from the south. The channel crosses SR-169 to the north in twin 24-inch
diameter CMP culverts. The stream then flows west along the north side of SR-169
before turning north through two 18-inch culverts (in series) and continuing north
between Regis Park and the Maplewood golf course.
Photos 27-43 illustrate conditions in the roadside swale and downstream in Stream A.
The following narrative describes the conditions observed during the site visits and listed
in the table in Appendix A. I.
J:\1509320 I\ Wonderland Estates\06\AprilTIR 9 DRAFT 4/912019
HLIITT-Zf)LIA::__::I:_:::(S __ ~~
HUITI-ZOLL.I\RS, INC. • 814 E. Pike Street • Seattle, WA 98122-3893 • 206.324.5500 phone • 206.328 1880 fax • huitt-zoll;ws.com
Drainage Element SJ (see Photos 27, 28, and 30)
This 12-inch pipe is located adjacent to the northwest comer of Wonderland Estates. It is
intended to convey road runoff and Wonderland Estates runoff under the Pioneer Place
sidewalk to the west along SR-169. Huitt-Zollars field survey indicates that the culvert is
laid at an adverse slope, with the west invert at an elevation of 99.63 feet and the east
invert at an elevation of 99.57 feet. The topographical low point on the Wonderland
Estates property is 98.5 feet at a catch basin rim in the northwest part of the site (see
Figure 3) and at the fence at the northwest comer the elevation is 99.67 feet. Because of
the elevation difference between the on-site low point and the pipe invert, runoff must
pond on-site at least I foot before drainage to the west occurs.
Drainage Element S2 (See Photos 29 and 30)
S2 is a shallow, wide vegetated swale leading to the west, with an average bottom width
width of about IO feet and an estimated slope of 0.4% based on the road grade.
Drainage Element S3 (Photo 31)
S3 is an 18-inch diameter concrete pipe under an unused access road.
Drainage Element S4 (Photo 32)
S4 is the trapezoidal swale downstream of pipe S3. It has similar characteristics to S2.
Drainage Element S5a and 5b (Photo 33, 34)
SS is a 12-inch diameter, 311-feet long steel pipe under 1451h Avenue SE (the entrance to
Pioneer Place). The first section (S5a) empties into a manhole in the middle of the street.
Section S5b continues from the manhole to discharge to the vegetated swale (Element
S6).
Drainage Element S6 (Photo 35)
S6 is a shallow triangular grass-lined channel. Its original geometry may have been
altered by grading associated with the construction of the Pioneer Place detention pond.
Drainage Element S7 (Photo 36)
S7 is an 18-inch diameter concrete pipe that discharges the roadside swale runoff to
Stream A.
Drainage Element SS (Photo 37)
S8 consists of twin 24-inch CMP culverts conveying Stream A under SR-169 to the
north.
J:\1509320 I\ Wonderland Estates\06\AprilTIR 10 DRAFT 4/912010
Hll!TT -ZC)Lli\RS --------
HU I TI -ZOLLARS. l NC. • 814E.PikeStreet • Seatt1e,WA 98122-3693 • 206.324.SSOOphone • 206.328.1880fa,. • huitt-roiars.com
Drainage Element S9 (Photo 38)
S9 is the large swale along the north side of SR-169 leading to the west. The bottom
width varies from 4-5 feet, with typical sides slopes of3H:IV. The depth from the edge
of the trail pavement to the bottom of the swale is typically about 3.5 to 4 feet.
Drainage Element SJO (Photo 39)
Stream A is conveyed under the Cedar River Trail and an abandoned Park road in a series
of two 18-inch diameter CMP culverts.
Drainage Element SJ I (Photo 40)
The system downstream of SI O is an open channel. At the outlet of the second culvert,
Stream A is a wide shallow channel with sideslopes overgrown with blackberries.
The channel bottom width is about 4 feet, with 4H: 1 V side slopes. The defined channel
is about 1 foot deep, with the overbanks forming a broader flow path to the north, with
the left overbank about 40 feet wide and the right overbank about 100 feet wide.
The Stream A channel is blocked by the park road/trail that parallels the stream on the
east and turns across its path to the west. The trail in this area is at an elevation of 90.4
feet (NA VD 88) and forms a hydraulic barrier to further flow to the north toward the
Cedar River. Discharge to the north has been blocked, probably due to grading
associated with earthquake/slide response after 2001.
Backwater analysis using the King County Backwater program (KCBW was performed
on Stream A and the swale system, as described in the March 16, 2010 Draft TIR. The
analysis showed that drainage element S 10, the 18-inch diameter CMP culvert under the
Cedar River Trail, restricts the 100-year runoff to an extent that causes flooding over the
trail. Upgrading the capacity of element S 10, and restoring the outlet of Stream A, which
would produce lower tailwater elevations, would reduce the potential for flooding in the
Stream A system.
The backwater analysis also showed that element S5, the 12-inch pipe under the Pioneer
Place entrance road, is undersized for the 25-year runoff event.
SECTION 4
RETENTIONIDETENTION ANALYSIS AND DESIGN
This section describes runoff analyses for the on-site sub-basin (named Sub-I in the
model) and the road sub-basin (named SR169 Basin I) that contributes to flow in the
roadside swale system.
The commercial stormwater modeling software StormNet was used to compute peak
runoff rates and volumes. The model implements the SBUH method and uses the Type
I A rainfall distribution, with 6-minute time steps.
J:\1509320 I \Wonderland Estates\06\AprilTIR 11 DRAFT 4/9/2011
HLJITT--21JLL'\RS
HUIIT-ZOLLARS,INC. • 814E.PikeStreet • Seattle.WA 98122-3893 • 206.324.5500phone • 206J28.1880fax • huitt-zoll.rs.oom
The design storm volumes used were obtained from the KC SWDM isopluvials and are
shown in Table 4.1.
bl Ta e 4.1 24 h d -our . f: 11 esum storm ram a . d . h ma mtu es, me es
Return Interval, vears Rainfall Ma1mitude, inches
2 2.0
10 2.9
25 3.4
100 3.9
Flow lengths, and conveyance roughness values used in times of concentration
computations, as well as computed times of concentration, are shown the StormNet
reports.
PART A EXISTING SITE HYDROLOGY
The existing conditions are those as of 1979 (per the KCSWDM).
d 1 Table 4.2 Ex1stm2 Site Hv, ro o<>v Summarv
Land Use Area, acres % Area
Impervious Impervious,
acres
On-site Basin (Sub-I)
Single-Family 7 dwellings/acre* 5.25 56** 3.94
Roads 2.98 100 2.98
Other Impervious 0.66 100 0.66
Forest 1.30 0 0
Grass/landscape 2.0 0 0
Total 12.2 62 7.58
* asswned
** assumed from KCSWDM based on land use
Soils on site are mapped as predominantly "Urban Land" (Figure 7). The steep forested
slopes in the southern portion of the Estates are mapped as Alderwood and Kitsap Soils,
while the area on the flatter slopes surrounding the Estates is mapped as Newberg silt
loam. The flatter area of the Estates is asswned to be Newberg silt loam based on the soil
map. Table 4.3 shows hydrologic properties of site surface soils.
J :\ l 509320 l \ Wonderland Estates\06\Apri\TIR 12 DRAFT 4191101D
l-iLlllT-ZC)LL'\RS
HUITI ·ZOLLARS, INC. • B14 E. PiKe Street • Seattle, WA 98122·3893 • 206.324.5500 poorle • 206.328.1880 fa. • hurtt.zollars.com
Table 4 3 Site Soils
Land Use Soil HSG CN Area, % Area
acres Impervious Impervious,
acres
Single-Family 7 Newberg B 98 2.94 56** 3.94
dwellin<><iacre* 80 2.31
Roads Newbern: B 98 2.98 100 2.98
Other Impervious Newber2 B 98 0.66 100 0.66
Forest Alderwood/Kitsan C 76 1.30 0 0
Grass/landscape Newbern B 80 2.0 0 0
* assumed
** assumed from KCSWDM based on land use
A composite CN of 81.9 was computed for the site using the data in Table 4.3.
PART B DEVELOPED SITE HYDROLOGY
Developed site hydrology is modeled conservatively as being the same as existing
hydrology. In reality, some impervious surfaces will be removed (4,550 sf tennis court in
south portion of parcel; roads will be narrowed slightly). For assumptions and
parameters, refer to Part A above.
HYDROLOGIC RESULTS
Because existing and developed site hydrology is considered the same for this project, the
results are the same and are presented in Table 4.4 below.
T bl 4 4 H d I . M d I R u1 a e Ly, ro O!!IC o e es ts
Basin Area, Return Interval, years
acres
2 10 25 100
Peak Runoff Peak Runoff Peak Runoff Peak Runoff
Rate, cfs Rate, cfs Rate, cfs Rate, cfs
On-site (Sub-I) 12.2 1.44 3.36 4.52 6.42
StormNet output reports for each return interval are included in Appendix B.
PART C PERFORMANCE STANDARDS
There is no applicable area-specific flow control standard or water quality control
standard.
J:\1509320 l \ Wonderland Estates\06\AprilTIR 13 DRAFT 4/9/20111
HLJ !Tr-2r)LL!\RS
HUITI-ZOLLARS, INC. • 814 E. Pike Str&et • Seattle. WA 98122-3893 • 206.324.5500 phone • 206.328.1880 fa,. • huitt-zollars.com
The conveyance capacity standards are as follows:
• Pipes designed for 25-year, 24-hour storm;
• Structures to have 0.5 ft freeboard for 25-year storm
• For the I 00-year runoff, pipe surcharging and overland flow is allowed under the
following conditions:
o Runoff is contained within defined conveyance system elements without
inundating or overtopping the crown of a roadway, AND/OR
o No portions ofa building will be flooded, AND/OR
o If overland sheet flow occurs, it will flow through a drainage easement or
covenant.
PART D FLOW CONTROL SYSTEM
No flow control system is required or proposed. Current discharge rates to Madsen
Creek and the swale system are to be maintained.
PART E WATER QUALITY SYSTEM
Not applicable; water quality facilities are not required for this project.
SECTIONS
CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Figure 11 illustrates the preliminary drainage system schematic. Pipes Pl, P2 and P3 are
conveyance laterals on a 1 % slope. Each storm lateral will convey approximately 1/3 of
the 25-year site runoff, or 1.5 cfs. Pipe P3 conveys runoff from the east part of the site to
the existing pump station near the northeast comer of the site. Flows in excess of0.3 cfs
(maximum pumping rate) are conveyed in the overflow pipe to the Pump Station Storage
Pond. Pipe P4 conveys the combined flow of PI and P2 to the west pump station. The
west pump station capacity is also 0.3 cfs. Pipe PS conveys flows from PI and P2 to the
west pump station. When the pumping capacity is exceeded, PS carries runoff
commingled from the entire site. Flow in PS is limited to the pumping rate, or 0.3 cfs.
The system is designed so that when the maximum pumping rate (0.6 cfs) is exceeded,
water backs up into the Pump Station Storage Pond. As the runoff peak passes and the
pumps catch up, the pond is dewatered.
The design capacity of each of the five pipes is shown in Table 5.1. Calculation
worksheets are shown in Appendix C.
J:\ 15093201 \ Wonderland Estates\06\AprilTIR 14 DRAFT 4/9/201IJ
HLllTTZ{)_LLAI ____ ~S __ _
HUITI-ZOLLARS.INC. • 814E.PikeS1reet • Seattle, WA 98122-3893 • 206.324.SSOOphooe • 206.328.18801ax • huitt.zolla-s.com
Table 5.1 Summarv Table of Conve) ance Caoacitv Calculations
Pipe Diameter Pipe Slope Required Design Capacity
(inches\ (%) Caoacitv ( cfs) (cfs\
Pl 12 1 1.5 3.83
P2 12 I 1.5 3.83
P3 12 I 1.5 3.83
P4 12 0.75 3 3.32
P5 12 0.75 3 3.32
All of the 12-inch pipes have sufficient capacity.
SECTION6
SPECIAL REPORTS AND STUDIES
No special studies beyond those described were performed as part of the preliminary
design
SECTION7
BASIN AND COMMUNITY PLANNING AREAS
No basin or community planning area requirements apply.
SECTIONS
OTHER PERMITS
Grading Permit
NPDES Construction Stormwater General Permit
SECTION9
CSWPPP ANALYSIS AND DESIGN
There are no areas of particular susceptibility to erosion. The steep slopes in the southern
portion of the property will not be disturbed.
Part A ESC Plan Analysis and Design
I. Clearing limits
No clearing will be required.
J:\1509320 I\ Wonderland Estates\06\AprilTIR 15 DRAFT 419/2016
Hll!TT-ZC)LLL\I~ -----------
HUITI.ZOLLARS, INC. • 814 E. Pike Street • Seatlle, WA 93122-3693 • 206 324.5500 phone • 206.328.1880 lac • hu1tl·zollars.com
2. Cover measures
Cover measures will be employed for all soil and material stockpiles that are potential
sources of pollutants in stormwater runoff.
3. Perimeter protection
Silt fences and/or straw wattles will be used at all downslope locations along the
perimeter. Note that the site is lower than most of the surrounding area, and does not
drain naturally except during heavy rainfall.
4. Traffic area stabilization
Suitably stabilized site entrances exist at the site.
5. Sediment retention
Not necessary due to site topography. Storm drain inlets will be protected. The detention
pond associated with the pump system will be used for temporary sediment retention.
6. Surface water collection
Surface water will flow by overland flow during system construction.
7. Dewatering control
Water generated by dewatering will be treated, if necessary, and discharged at an
approved location.
8. Dust control
Dust control will be provided using water, as necessary. Water will be applied in
amounts that will minimize runoff.
9. Flow contro 1
Flow control will be provided by the project's current flow control facilities.
Part B SWPPS Plan Design
Potential pollution generating activities are limited to soil disturbance, the operation of
equipment, and the storage of materials associated with the equipment. Appropriate
materials storage and handling BMPs.will be specified.
The proposed receiving water is the roadside swale leading to an intermittent, Class 3
stream. There are no special water quality issues associated with this water course.
J:\1509320 I \Wonderland Estates\06\AprilTIR 16 DRAFT 4/9/2016
"-
HUITI-ZOLLARS, INC. • 814E.PlkeStreet • SeaWe.WA 9a122-l893 • 20fi.3245500phone • 206.328.18801ax • hurtt-z~lars.com
SECTION 10
BOND QUANTITIES, FACILITY SUMMARIES, AND
DECLARATION OF COVENANT
To be provided with final TIK
SECTION 11: OPERATIONS AND MAINTENANCE MANUAL
To be provided with final TIR.
J:\ 15093201 \ Wonderland Estates\06\AprilTIR 17 DRAFT 4/9/20111
l~LIITT-ZC)LLAJZ_\
HUITT·ZOLlARS, INC. • 814 E. Pike Street " Seattle, WA 90122"3093 " 206.324.5500 phone • 206.328.1880 fax • huitt-rollars com
REFERENCES
Adolphson Associates, Inc. 200 I. Madsen Creek Tributary Erosion Stabilization Projects
Biological Assessment, prepared for King County Department of Natural Resources
Chow, 1949. Open Channel Hydraulics
ESM, 2005 Final TIR for Pioneer Place.
King County Surface Water Design Manual, 1990
King County iMap, http://www.kingcounty.gov/operations/GIS/Maps/iMAP.aspx
accessed November, 2009
NRCS Web Soil Survey, http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx,
accessed November, 2009
J:\1509320 I \Wonderland Estates\061Apri1TIR 18 DRAFT 4/912019
Page1 au
King COUnty Bulldlng 1111d Land Development Dlvlllan
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
ProjedOwner khlr eou~iTt :flo11(1~ l\m,tt
Addnlsa !oo MDfVlfll. rw we,,: T11Kw1L-A--
Phane (1,.rt) O'l-11!' 7
Projed Engilw 001,1 i!EI utt&-
campany iff,(IT-'Z.~ I 1tJL.
Al*!s-Phane Sri E: Pfll ·C:: 'Et:f!t4
D SUll ~Milan
D Shall SWc:lviaiafs
D Grading
D eamn.n.i
'
iiZ'.J OIi.-CllffitM..-IUrE,<8'r,,./J
PART J If [ cc;.1i.'LirJITY >'it;O OP,'..l'o'\GL ui\'_,ltJ
Community
0 DOFIGHPA
D COE404
D DOE Dam Sully
c_· • FEMA f'bicll*i,'3
D COEWd•NII
D Shal9h Management
D Racury
D Shclural Vaullls
D on.r
D HPA
D Rlv9r __________ _ [i)Floadp~------------
[J] &n.n IIAH>'6N tME IC..
D CrillCIII ~ RNd1
[]!I Weltandl ------------
D DlprNllonlfSwal
0 S11p1'Spk1g1
0 HghGnuwlwallrTIDle
D Gnlundwar Rectsasge D Laska-----------
Cil SINp Slapee D Olher -------------
D~Hazanl
PMlT 7 SUILS
Sol Type Slopes Erasion Polential ES'Olhle Velocltiaa
fA/lMsJ (u,) t.,ilitvfflti\tJ Llli°N(Ha) I:.~ ..... ,,...L='""''-"--'-T ___ _
4'=#"''"° i ~ 1,c-,er,Ec
l'IT!,t-P Gtk. e) ( f+6T j,@.ijtp )
D Addllional ShNla Attatched
1/90
Plp2ol2
King County Building and land DevaloprMnt Dtvlalon
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
PART 8 OEVELOPl.1ENT Lll,IITATIOtlS
REFERENCE LIMITATION/SITE CONSTRAINT
D Qh. 4 -llownsb:,am Analysis
D
D
D
D
D
D Additional Sheets Allalc:hed
PAm "I ESC f1EQUlf1Er.1Erl,',
MINIMUM ESC REQUffMENTS
DURING CONSTRUCTION
00 ~olalonFIICIIIIN
MINNJM E8C REQUIREMENTS
FOLLOWING CONSTRUCTION
D SWll!zeE.-«!Sul1-
D Slabillzed Conllluc:tlon Entrance
[!] Perlmela Runoff Conlrol
D Fi.n-and RNIDN T~ ESC FacilillN
[XJ Clean and "'"-All Sit and Dlbrle
D C1Nr1ng anc1 Glwlln11 RNtrlctiona
D eo....r Pi.:licN
lil Conalrucllon Sequ«,ce
D oii.r
p,.\RT ,o SU8ri\Cl \'JATER SYSTEr.1
D Grasl.NdChannet D Tri
[XJ Pipe Systam D Vut
D Open Channel D E'*V)' Dllupal0r
D Dry Pond D w.lland
D w.1 Pond D SlfNl11
Brief O.Ulpion of Splem Operation
Facil\y Aelalld Sita Umitations
R ... ..,.. Faclllly U-
[i] en.w. Operation of Pem,-,1 FaclllllM
0 Fllg Umll9o1N0PES
D otier
D 11a,111b1
D DIF slnr
D Fl:wDilpelul
OWriver
D Ragionll Delsntlcn
PMH 11 ', THUCTURAL MrnLYSIS PART 12 t:A.sr::r,1uJ1J TRACJ::i
1 r.uy n qu1rp , p1cc1.•\ ':.>lructur,.I rl'VlPW)
D Castlnl"-Vut D Ollwr
D Rellinlng Wal
D floc:Mly>4'Hgh
D Slrumlnll on s..p91ope
f'AfH 11 ',IGrJATURE OF PR0FESS10t1AL EtiC>1llEER
I • 1 clvll lllfllllW undtr Ill)' aupamslnn i-'1.,... ._ --.i
19111 .-••an1 • ab served -~-,ornMl lnlD -_..,_and._
et t111alltL To ... belt of IIIJ lulO•dgt ... 11 .. iWliwl pN'lftd1d
'*919-....
D DrainSlge Eaaament
D AcceuE•1ment
D Nlltiw 0/owth "'Pl""ullcllo,.....,,...,n E111rrent
D Tract
OOIIW
"'·
1/90
t-!Ll!TT-Z( )LL'\RS
HUln-ZOLLARS INC. • 814 E. Pike Street • Sealtle, WA 96122-3893 • 206.324.5500 phone • 206.326.1880 fax • huitt-rollars.com
Figure 2 Site Vicinity Map
__ ...
\ i_( ____ H7rMSJ
1:.l::: Ill,··:~._
• a
i
--...
-........
J :\1509320 I\ Wonderland Estates\06\AprilTIR DRAFT 4/912011
,.. .. .. ........
I -I --L--------
i r
. .r /.
!,',
' i .J.
i
i •: I
.·· I: I
I:
Ii!
I,
'\ !
.i I
:1'
co
C:
0 ·-en
Q)
0:::
.c
M
Q)
I,,.
:I en
LL
l
..
i ! i
.: ..... .....
I ,
_,,,, .•
•
.._
• ' • • I •
)
\
I
) .... , .,
' .... ..
I ,,
._ ...
--
.. _ , •
. -! •
I
I
I:
i
••
ti
t'
!1
I
\
J
' . I
! ,I
.........
<' • I ' . :
• r
•
' f •
4r28'4"
'1" 2 7 42"
Soil Map-King County Area, Washington
Map Scaia: 1:3,330 r plltUd an A ... (8.5" x 11; lhoet
--i===----i=====IMele·n 0 3) 60
0 100 200
usge Natural Resooo;es
ConMrvation Ser.ice
120 180
eoo
Web Soil S urvey
National Cooperative Soil Survey
11/3/2009
Page 1 of 3
D
JI ,1
I
u
I
l :! ~,
1 c l o i <> • .._ 'O' <> • :,: + < • • lO • ;:,,, 0 :• X • 3*E B E i ..
1nnpn11ri 1 1J[(if f 11i !I
f f I 1 Ii f j f J J f f 1 If J I 1-
1 . > f i I g ~ .-m
~ • I Q
~>~~l,(1 1 •1~:t i••a !
i!iP nf rhn,'lp E
'' f i I I I
if! i I JE ;i l'f JI' l l i Ii , ,I 1i I:~ i I f
J
f lJ i: if Jar 1°'f f . ~ i ; ?I~ I ,. ·· ~1 -. ~ ' i ! i
i t 1 <z I .. f r f I ~ J }f ~ iv If ~,:DI I · z 'I i i ~, · : r~ ! g o i i-t 9 I 1 f 5 11J , ! t 1 · i , a . . -1· i i I i • ~ ~ . r: ~ &J M. 1 • o 111. s ! ~ r f 3 z t r i r if n IL I
1 I i 1 i i
J ~ J J
('4~".?) L i ~lj
j
J
1
i
Map Unit Legend
.... c...,. AIM.~ ........... ~
11a,u.a-... .... Unit ..... AclNlaAOI
~ AIIN!woOll lflCI Kltlap loll. -,y ..... ,.o
Ng ~ lilt loam 31.2
Py Puplql h 1ancly loam OA
Ur \Mlan lend 13.2
T.W. fot AIM., ........ 6U
......... elAOI
11.1%
~.0%
0.8"4
24.5"4
100.K
11/3120011
Pafe3of3
Oolr.117<2010 -:~c«,,1),-·--o.--~
t I COllnty llounary
X .......... Ptah
I ' Contours (IOttl 11th!)
Highways
Parctlt
0 Parlet
legend
2007 Color Aerial Photoo (lln)
ZD07 Color Mflal Pholoo (121n)
SlladtdRtlitf
0 (.( r ,:fc. ;h.," ''1-' :.1
l.',.,.,'1-~
p1,,,l-1,,,1~rf /oco:/i'.n,..
(/r/(7t,-,~.'K ,4.J)
-_____ ..... -.-... ---~-........................ ,,.., .. , l•tlKlngCounty ...-.... __ ,,,,_ -
u,
w
~ >-< (!) ~o u, ...I WO
0 0::: Zo < > ...I J: o:::w w~ o_
Zu,
i
----·~ -~ -·::-::
~
._,. .... ,, .. "'·'"'
REPLACE EXISTING
SEEPAGE INTERCEPTOR
... .,.,..-.. ,o:r
, . \ ' ~ ' ,, -. , )J \:
',' fr\ i:-.:.i i L' -·
'~-·-1 ··~-' T,:1--1
.' :1c-'1,·,i
'\ L_ -~,
'I ' I[ i:
\ 1 \\":-;,;"_-:··
\ : \ ! ·._ ~
~~
·,--1-
1_,_1;, ··:-I
I--:··· 1 . I
·· I · , I I _',.-,,·,.-.-J
.. --
'"
·.,.:,.,.,
I . I I
I ... ,!. -1
'w.-,.~i
D P1..
.~' ,...../iil\ib
t
PUMP STATION
STORAGE POND
l,L_._ -
-·-• I I: -~-l •· '· Lccc~-=-;~----,-~
NEW DUCK PONO
OVERFLOW WITH
DEBRIS BARRIER
~f : \ ,,-, '/ ' , __ .
\L\[1 '_ 1. -o-·-~---,,. , ~ ·:_··• .·.\tV•,:, -._. !
, I, ,; :·_t
} ;Ii
' ' '.' ":/ rf?~, \
... 'f o , __ '.p:, ··oc:'-,
I
' J
~~~(~;~
J. 1·····
;;
'I. ±:;---·o.~
·~-~--1-·r~:---_-::>L--:-_.:-~~
, • r
.\ i i' , I ,
~RFLOW / {. e
i-_:; ' .
:11 j c: I i' ~--, ,</~?_"'.
' ' (('/'''
'1, 1/. :Ut:· .i-.
' --,-,
,,,..oo,;,,..
,,---
rn,&,,,moo ·I ·--;._-n""j;
. :1 ··1 :1
,e 'i ,_1. I 1-t 'j et LJ.1 I . , , , ., • : I r , <1
···'i I · L:, ·
• I t ; ~~ -. '. . --~ '~"'-'~--------=-:~: ·----
T,"1
HUITr-2U.JARS
-~ _. __ · ,,,:-o~,.-~_ , ... ,,.
WONDERLAND ESTATES
PRELIMINARY DRAINAGE SYSTEM
I -"PlijE 'I L .r .
'~-->·
I ;:
I
I
,-~ .. ' • "'li'I"' ~ I :.; ' I ····. / ,_
:.t. -• .-':·J
f!r
UNPLATIED
T.L. 9118
UPGRADE EXISTING ~
PUMP STATION
/'"'',•·-·.,
''"'"" ~-n,:;11. SCALE (IN FEET)
a '° 80
/:
' I'-"~ :
'
J
Ql,l.~
' m,~
f1fHVl;.l
i hlO
:{ LPGRAdE EXIST
PUMP SrTION i
" m
~ z
" 0 z < > ~ m
~
' ' " ~
;;;
" m
I
160
"""lFi'GURE:
11
_j
~/
'
------
'
c-r,
I
I
I
~
I
I
I
' " , . . ,
• ,jg
111 I
;-,, ·\
'' ),
' ,
' ' ' ' ,
':. . ' ,· '. ! -~
!'f.
,
' , ' : ' ': } ;.,
' ' :f ........_ ---........ -_/ . '.
'•}'
~ f ~
HUITT-20.JAAS
---·fl,.._
,"J!f ,. '. ~!
'~-~.!-
,:
--...........
----.,~4~,~---' ~
ct ) -~ ~--! .
··~'i.c
-~---o ..
~ ;:.
-__ }t_ """"-.......
-.r11-.
PONO DRAIN 11NfLOW __ ~(:.~,/i'. ·-----.
::.~
;/,, .. .--;· I
, ' l,
~ .r8!;
~J)!;
,;,;
l,! i SPILLWAY i ·, .
I, : i f.'1Y f.'i_H/I , 1· /t QT -... ~~ I ,
. r· --. -. . . ·-·-'" . .,_. ~-~"---,,, . , ,·
..
.. · : .· .. ; ' . ~.:,;;;,. · .. :i.·,:. ' ... :•,. I I I -.. :~~_r< ' . ' .,.,· 0:;,-:1.:, I •
~ . --
__ : ·--:_,-,'-.\ '/;/~ ,..,
l j
0 ,, / ;
I -I •
~efJ (ru ;11 JI '!!! ,·~ Ii;•
WONDERLAND ESTATES
PRELIMINARY DRAINAGE SYSTEM DETAIL
"'
~'L;_,.
s ... . -
£; R<-N.,. . ~-.
"'· 1 0N . · -. __ ·MAPi_f: --~
· VAli_£y
,. • · . . ~Pa.essuRE o,sc_HARGE RoA,
''.:---_
j ·-.
(l
TO MADSEN C~EEKAS IS
f
I Id' ~;..£,i h, 1~1?.-rg
:> -:-----
J
$
UPGRADE EXISTING
PUMP STATION
0
SCALE (IN FEET)
20 " !FIGURE:
12
80
HUITI-ZOLLARS, INC. • 814 E. Pil<.e Street • Seattle, WA 98122-3893 • 206.324.5500 phone • 206.328.1880 lax • hoitt-z~l.r-s.com
APPENDIX A:
OFF-SITE ANALYSIS SUPPORTING DOCUMENTATION
A.1 Off-site Analysis Drainage System Table
A.2 Photographs
J:\ 1509320 I\ Wonderland Estates\06\AprilTIR DRAFT 4/9/201D
~il lllT -zt)LLAltS
-----··
HUITT-ZOLLARS. INC. • 814 E. Pike Street • Seattle, WA 98122-3893 • 206.324.5500 phone • 206.328. 1BBO fax huitt-iollars.com
A.1 Off-site Analysis Drainage System Tables
J:\1509320 (\Wonderland Estates\06\AprilTIR DRAFT 4/9120171
0FF•SITE ANALYSIS DRAINAGE SYSTEM TABLE
SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2
Basin: t.. (J"" ,(/ r, t! Iv I{. ii ,v Sabbasln Name: /1'11( /r,e..., ('l',~f.. Snbbasln Number:
~
Symbol Drainage Drainage Slope Di.tance Existing Potential Oburvatlona of field
Component Type, Component from site Problems Problems lnapectDr, rnource
Name.and Size Descrlntlon discharge revle-r. or resident --Tp:--.-. .,..__ .. ,__.,, % Y. ml• 1,320 ft. -· -CllpllC:il)'. ponding, ~-. or...-m. ,,., ... ,) -.dlalW10l.llil>o, .... ,. deplt,, lype .,_ OV8rlopplng, toadlng, hablol or ...-,n ......-pa"-, polentlal lmpacto
pond; Size: dll-. area,valume
-· oc:ourtng, -sloughlna, aurfaca .,.. ---·--1"11 ':l_•n,;-, v•-, ., ' ._ .. ,.,.--2 ,. O' /,/., .,1:;., ,..,.,.11.-.,,, ;) .......... ,i'~h~ ,.., ,. .. 7,,..,-t ~ JJ,. i,e I
m, Q ~''I-c .. t11e;r I •/. 10' ,._,,.,,,,,~ .. t'.-.rfl...U',~ . ,
Al 3 l'3'v'1'•,,'-t,.111111 n,1,. 2.c>o I Ji.6. .. u,,6' p,., ••• -,. ' .,
NI'/ ~f!~ ~~,:~~ 0.1,., ii.o' s,J.., .. f,J,iM,.. Pt.,.11.~, ••
N)~
~'v .. e,,,,,.,. o. '.3t fSo • S'd,;,,,, .. fr.f,. .. -
t --~~e,. ••
""' --!t•~II:'-c'i., _ o.,,. 17S.J I ~ .. .. . ,~
,, e~ti "".+rd
" ({)111d1:fi,..._ t)n·-+r,f p,,.._ /tl;,1/ltJ-, ZIN•. 119/2009
L.,w~/
Basin: (etbr d,itf'/
Symbol Drainage
Component Type,
Name. and Size
... ffllll -"' Type: lneet flow, IWllle,
(h'wc4, IVOlm. dlannel, pipe,
pond; Size: diameter,
aLl'face ... ,, , Z • c-f,-, I n.'~e,.
5'2. , .
1,~41 •,i.,1.;(,c..
{'", ,.r:,·-r ,,"'r . ., :~"
S'f • • ,,-. . S'1,1,fc..
s; .t •
1 l. r+,,r "·• e.
'" ' .
Vt'A <tu,itl<,
<;7 ,t"· . , r,:uK. •. •t.
5'3 2. ~ 1.1(' C:,. i
Stl 1//04 .f1,1e,(,
~/J 1s··· rh'lf
5 , , ,, '"' ,;,_, ~,, ,
OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE
SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2
Subbasin Name: /11 '( / ,.,,, Cruc Subbasin Number:
Drainage Slope Distance Existing Potential Observations of field
Component from site Problems Problems Inspector, resource
Dffcrintlon dlscharne rev1e-r. or resident
ClrU\IIQe basin, vegetaltOn, % ~ml= 1,320ft. -· ..-.. padty. pGndlng, ~-. of problem,
cowr, depth, type of sensitive O\IOllopplng, flooding, hablta1 or organism --..-,., polllnllal imf>«a area, volume dfltruc:tion, ICOuring, bani< llougt,lng,
oedimenlatlon lndolon other erosion
-o.3 I:; ,:.~:;;; .. , l
t, 1 '"" ~1.,.,1,;.. . ,-
J,:,' ,., 'IC 2 ' ,, n,') Z.o
a.J 'lo.~ ,., . ,., .. ;,. . () 0. '.l 4 Z,.,
0 '.) 7'1.J '"'·•!: -,if .. ,.,. -/:{.,-:,/;;,,; 011~_-:·•"' ,-"" ' -.. -.J/w, 4.C&--
,'..,,,,, .. w. 1S'1,1 0, '3 J/t),;1
. I ,
0' 'J lluo
11. '} I 2-tl "
'1-S 'n. w. t' F) 0 ') /} 'J 0
' !Hoo ra,1.,e,.P., ? Cl.>, I,",., ,;:,1 .... ::;,•.., -, • ~.'l -'f-$ • f!> I.I n.)
. .
l' t> 2. 'f o.::> .
1/912009
l lLJrll~)LliJZ_\
HUITT·ZOLLARS. INC. • 814 E. Pike Street • Sea1!1e, WA 98122-3893 • 206.324.5500 phone • 206 328.1880 fax • huitt-zollars.com
A.2 Photographs
J :\1509320 I\ Wonderland Estates\06\AprilTIR DRAFT 4/9/20Jg
Photo I , November 4, 2009: Wonderland Estates along west boundary (Pioneer Place to
the right) looking south. Steep forested hill to south in background, and Madsen Creek
opening through hills to the left.
Photo 2, November 25, 2009: Wonderland Estates, duck pond in southern portion of site.
The pond receives seepage interceptor discharge and overflow to the storm drain system.
Photo 3 , November 25 , 2009: Madsen Creek Sediment Pond, looking south from north
berm.
.
Photo 5, December 20, 2009: Madsen Creek Sediment Pond base flow outlet ; 36-inch
diameter CMP culvert.
"""
.~.
Photo 6, January 8 , 2009: Madsen Creek Sediment Pond base flow o utlet; controlled 42-
inch diameter CMP culvert in foreground. Note at this water surface elevation, the
bypass channel i s flowing (see Photos 7 and 8).
Photo 8 , January 8 , 2009: Madsen Creek Sediment Pond high flow bypass outlet during
high flow conditions.
Photo 9 , January 8, 2009: Madsen Creek high flow bypass channel along eastern
boundary of Wonderland Estates during high flow conditions. View is to the north.
Photo 10 , January 8, 2009: Madsen Creek high flow bypass channel under SR169. View
is to the north. Drop vi sible in photo is due to Madsen Creek main channel box culvert
crossing the bypass channel from east to west (see Photo 11 for dry conditions and Photo
12 for wet conditions).
Photo 11 , November 4, 2009: Madsen Creek high flow bypass channel south of SR169.
View is to the SISE. Madsen Creek main channel box culvert visible in photo , and
concrete wall to keep Madsen Creek out of bypass channel.
Photo 12, October 15 , 2009: Madsen Creek high flow bypass channel north of SR169.
View is to the north.
Photo 13 , October 15 , 2009: Madsen Creek high flow bypass channel outlet culverts to
the Cedar River.
.
Photo 14 January 8, 2009: Madsen Creek behind bypass channel during high flow. View
is to east, flow is to west in Madsen Creek, to north in bypass channel.
Photo 15 October 12 , 2009 Madsen Creek exiting box culvert under bypass channel.
View is to east, flow is to west.
' -~~
-~-~::o...........ii.a.ii.;a:; • ..____.:..;:;__...,_.wo_.....:.. ~=;_..:;:...:i...-,.~ , ~ • ,
Photo 16 January 8, 2009 Madsen Creek exiting box culvert under bypass channel under
high flow conditions shortly following flooding . Culvert submerged. View is to east,
flow is to west.
Photo 17 December 20, 2009: Madsen Creek in low flow conditions, looking east along
front of site; SR 169 on left ( drainage element M 1)
Photo 19 December 20, 2009: Entrance to Madsen Creek box culvert under SR169,
during low flow conditions.
Photo 20 January 8, 2009 : Madsen Creek inlet to box culvert under SR-169, view to
north, under high flow .
"'.
. . .,,;.~·
Photo 21 December 20, 2009: Submerged Madsen Creek culvert under 1491
looking south on east side of bridge (drainage element M3).
'
Photo 23 December 20, 2009: Outlet of submerged Madsen Creek culvert under 149t
A venue SE; Creek looking west from bridge.
Photo 24 December 20, 2009: Madsen Creek upstream of bridge in Regis Park, looking
south from bridge (drainage element M4).
Photo 25 January 8 , 2009: Wonderland Estates following flooding.
Photo 26 January 8, 2009: Wonderland Estates following flooding.
Photo 27 October 12 , 2009 : NW comer of Wonderland Estates looking west.
Photo 28 November 4 , 2009 : Inlet to twelve-inch culvert ( drainage element S 1) under
sidewalk at NW comer of Wonderland Estates. Note pipe is laid at adverse slope.
Photo 29 November 25 , 2009: Outlet to twelve-inch culvert (Photo 27) under sidewalk at
NW comer of Wonderland Estates. Note pipe is laid at adverse slope, inhibiting flow
from Wonderland Estates. View is to the NE.
Photo 30 October 15 , 2009: NE comer of Pioneer Place at beginning of roadside swale
(drainage element S2). Inadvertent grading has caused a low point near the fire hydrant,
allowing overflow from the swale to enter the landscaped area to the left. View is to the
west. The twelve-inch culvert (Photos 28 and 29) under the sidewalk is out of picture to
the right.
Photo 31 December 20, 2009: Inlet to 18-inch culvert in swale adjacent to Pioneer Place.
View to west (drainage element S3).
Photo 32 November 25 , 2009: Roadside swale (drainage element S4) from near NW
comer of Wonderland Estates, looking west.
Photo 3 3 December 20, 2009: Inlet to 12-inch culvert ( drainage element S5) under
Pioneer Place driveway. View to west.
Photo 35 December 30, 2009 : Wide, shallow swale (drainage element S6) downstream of
outlet to 12-inch culvert under 145th Avenue SE (Pioneer Place entrance) (Photo 34).
View to west.
Photo 36 December 28 , 2009: 18-inch culvert (drainage element S7) under access road to
Pioneer Place detention pond . Culvert discharges road and site runoff to Stream A
flowing south to north under SR-169 on the other side of the access road . View to west.
Photo 38 December 20, 2009: Stream A, drainage element S9 downstream of outlet to
two 24-inch CMP culverts on north side of SR-1 69 . View to west.
Photo 41 Stream A looking north from middle of drainage element S 11 ).
Photo 42 Madsen Creek downstream of wetland, approaching Cedar River
-
Photo 43 Current Mouth of Madsen Creek on Cedar River. Channel is perched about 3
feet above river water surface.
\.! ....____.
-------
HUITT-ZOLLARS, INC. • 814 E. Pike Street • Seattle. WA S8122-3893 206.324.5500 phone • 206.328. 1880 fax huitt-zollars.com
APPENDIX 8:
RUNOFF CALCULATIONS
J :\1509320 I\ Wonderland Estates\06\AprilTIR DRAFT 4/9/2018
Wonderland Estates 2-Year
BOSS International StormNET® -Version 4.14.0 (Build 16362)
****************
Analysis Options
****************
Flow Uni ts ................ cfs
Subbasin Hydrograph Method. SCS TR-55
Time of Concentration ...... SCS TR-55
Pond Exfiltration .......... Constant rate, free surface area
Starting Date .... , ........ FEB-09-2009 00: 00: 00
Ending Date ............... FEB-10-2009 00:00:00
Report Time Step .......... 00:05:00
*************
Element Count
*************
Number of rain gages ...... 1
Number of subbasins ....... 1
Number of nodes ........... 1
Number of links ........... 0
****************
Raingage Summary
****************
Gage
ID
Data
Source
Data
Type
Interval
hours
Gage-1
****************
Subbasin Summary
****************
Subbasin
ID
Sub-1
************
Node Summary
************
Node
ID
Out-9
TS-2
Total
Area
acres
12.19
Element
Type
OUTFALL
**************************
Runoff Quantity continuity
**************************
Total Precipitation ..... .
Surface Runoff .......... .
continuity Error (%)
**************************
Flow Routing Continuity
**************************
External Inflow ., ....... .
External Outflow ........ .
Initial Stored Volume ... .
Final Stored Volume ..... .
Continuity Error {%)
StormNET
INTENSITY
Invert
Elevation
ft
Volume
acre-ft
2.024
0 .065
0.000
Volume
acre-ft
0.000
0. 662
0.000
0.000
-0.016
97, 50
Maximum
Elev.
ft
97. 50
Depth
inches
1. 992
0.002
Volume
Mgallons
0.000
0.216
0.000
0.000
0.10
Ponded
Area
ft'
0.00
External
Inflow
Page 1
Wonderland Estates 2-Year
******************************************
Composite Curve Number Computations Report
******************************************
Subbasin Sub-1
Soil/Surface Description
Paved parking & roofs
Woods, Good
> 75% grass cover, Good
Composite Area & weighted CN
***************************************************
SC$ TR-55 Time of Concentration Computations Report
***************************************************
Sheet Flow Equation
Area
(acres)
6.58
1. 30
4.31
12.19
Tc= (0.007 * ((n * Lf)"0.8)) / ((P'"'0.5) * (Sf"0.4))
Where:
Tc Time of Concentration {hrs)
n Manning's Roughness
Lf Flow Length (ft)
P 2 yr, 24 hr Rainfall (inches)
Sf Slope (ft/ft)
Shallow Concentrated Flow Equation
V 16.1345 * (Sf"0.5) (unpaved surface)
V 20.3282 * (Sf"0.5) (paved surface)
Tc (Lf / V) / (3600 sec/hr)
Where:
Tc Time of Concentration (hrs)
Lf Flow Length (ft)
v Velocity (ft/sec)
Sf Slope (ft/ft)
Channel Flow Equation
V (1.49 * (R"(2/3)) * (Sf"0.5}) / n
R Aq / Wp
Tc (Lf / V) / (3600 sec/hr)
Where:
Tc Time of Concentration (hrs)
Lf Flow Length (ft)
R Hydraulic Radius (ft)
Aq Flow Area ( ft 2 )
Wp Wetted Perimeter 1ft)
V Velocity (ft/sec)
Sf Slope (ft/ft)
n Manning's Roughness
Subbasin Sub-1
Sheet Flow Computations
StormNET
Soil
Group
B
C
B
CN
98. 00
70.00
61. 00
81. 93
Page2
Wonderland Estates 2-Year
Manning's Roughness:
Flow Length (ft):
Slope(%):
2 yr, 24 hr Rainfall (in):
Velocity (ft/sec):
Computed Flow Time (minutes):
Shallow Concentrated Flow Computations
Flow Length (ft):
Slope (%):
Surface Type:
Velocity (ft/sec):
Computed Flow Time (minutes):
Channel Flow Computations
Manning's Roughness:
Flow Length (ft):
Slope(%):
Cross Section Area (ft 2 ):
Wetted Perimeter (ft):
Velocity (ft/sec):
Computed Flow Time (minutes):
Total TOC (minutes):
Subbasin Runoff Summary
***********************
Subbasin
ID
Sub-1
System
Analysis
Analysis
begun
ended
Total elapsed
StormNET
on:
on:
time:
Total
Precip
in
2.000
2.000
Thu Apr
Thu Apr
< 1 sec
OB
08
Total
Runoff
in
0. 646
0.646
16:49:59
16:49:59
Subarea A
0.10
50.00
3.00
2.00
0.19
4. 38
Subarea A
200.00
0.50
Paved
1. 44
2.32
Subarea A
0. 01
1000.00
0.50
1. 00
4. 00
2.79
5. 98
12.67
Subarea B
0.00
0.00
0.00
0.00
0.00
0.00
Subarea B
0.00
0.00
Unpaved
0.00
0.00
Subarea B
0.00
0.00
0.00
0.00
0.00
0.00
0. 00
Subarea C
0.00
0.00
0.00
0.00
0.00
0. 00
Subarea C
0.00
0.00
Unpaved
0.00
0.00
Subarea C
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Peak Weighted Time of
Concentration
days hh:mm:ss
Runoff Curve
cfs Number
1. 4 40 81.930 0 00:12:40
1. 44
2010
2010
Page 3
Wonderland Estates 10-Year
BOSS International Storm.NET® -Version 4.14.0 (Build 16362)
****************
Analysis Options
****************
Flow Uni ts ................ cfs
Subbasin Hydrograph Method. SCS TR-55
Time of concentration .•.... SCS TR-55
Pond Exfiltration .......... Constant rate, free surface area
Starting Date ............. FEB-09-2009 00:00:00
Ending Date ............... FEB-10-2009 00:00:00
Report Time Step .......... 00:05:00
**********'"'**
Element Count
**********'"'**
Number of rain gages .... , . l
Number of subbasins ....... 1
Number of nodes ........... 1
Number of links ........... 0
****************
Raingage summary
****************
Gage
ID
Data
Source
Data
Type
Interval
hours
------------------------------------------------------------
Gage-1
****************
Subbasin Summary
****************
Subbasin
ID
Sub-1
************
Node Summary
************
Node
ID
TS-10
Total
Area
acres
12 .19
Element
Type
INTENSITY
Invert
Elevation
ft
0.10
Maximum
Elev.
ft
Ponded
Area
ft'
External
Inflow
------------------------------------------------------------------------------
Out-9 OUTFALL
**************************
Runoff Quantity Continuity
**************************
Total Precipitation ..... .
Surface Runoff .......... .
Continuity Error (%)
**************************
Flow Routing Continuity
**************************
External Inflow ......... .
External Outflow ........ .
Initial Stored Volume ... .
Final Stored Volume
Continuity Error (%)
StormNET
Volume
acre-ft
2. B84
0.127
-0.000
Volume
acre-ft
0.000
1. 285
0.000
0.000
-0.014
97.50 97.50
Depth
inches
2.B39
0.004
Volume
Mgallons
0.000
0. 419
0.000
0.000
0. 00
Page 1
Wonderland Estates 10-Year
******************************************
Composite Curve Number Computations Report
******************************************
Subbasin Sub-1
Soil/Surface Description
Area
(acres)
Soil
Group CN
----------------------------------------------------------------------------------------
Paved parking & roofs
Woods, Good
> 75% grass cover, Good
Composite Area & Weighted CN
***************************************************
SCS TR-55 Time of Concentration Computations Report
***************************************************
Sheet Flow Equation
6.58
1. 30
4. 31
12. 19
Tc= (0.007 * ((n * Lf)""0.8)) / ((P"0.5) * (Sf"0.4})
Where:
Tc Time of Concentration (hrs)
n Manning's Roughness
Lf Flow Length (ft)
P 2 yr, 24 hr Rainfall (inches)
Sf Slope (ft/ft)
Shallow Concentrated Flow Equation
V 16.1345 * (Sf"0.5) (unpaved surface)
v 20.3282 * (SfA0.5) {paved surface)
Tc {Lf / V) / (3600 sec/hr)
Where:
Tc Time of Concentration (hrs)
Lf Flow Length (ft)
v Velocity (ft/sec)
Sf Slope (ft/ft)
Channel Flow Equation
V (1.49 * (R"(2/3)) * (Sf"0.5)) / n
R Ag/ Wp
Tc (Lf / V) / (3600 sec/hr)
Where:
Tc Time of Concentration (hrs)
Lf Flow Length (ft)
R Hydraulic Radius {ft)
Aq Flow Area (ft 2 )
Wp Wetted Perimeter (ft)
V Velocity (ft/sec)
Sf Slope (ft/ft)
n Manning's Roughness
Subbasin Sub-1
Sheet Flow Computations
StormNET
B
C
B
98 .00
70.00
61.00
81. 93
Page 2
Wonderland Estates 10-Year
Manning's Roughness:
Flow Length (ft}:
Slope (%1:
2 yr, 24 hr Rainfall (in):
Velocity (ft/sec):
Computed Flow Time (minutes):
Shallow Concentrated Flow Computations
Flow Length (ft):
Slope (%):
Surface Type:
Velocity (ft/sec):
computed Flow Time (minutes):
Channel Flow Computations
Manning's Roughness:
Flow Length (ft):
Slope (%):
Cross Section Area (ft 2 ):
Wetted Perimeter (ft):
velocity (ft/sec):
computed Flow Time (minutes):
Total TOG (minutes):
***********************
Subbasin Runoff Summary
***********************
Subbasin
ID
Sub-1
System
Total
Precip
in
2.850
2.850
Total
Runoff
in
1. 258
1. 258
Subarea A
0.10
50. 00
3. 00
2.00
0. 19
4.38
Subarea A
200.00
0.50
Paved
1. 4 4
2.32
Subarea A
0.01
1000.00
0.50
1. 00
4. 00
2. 79
5.98
12. 67
Subarea 8
0.00
0.00
0.00
0.00
0.00
0.00
Subarea B
0.00
0.00
Unpaved
0.00
0.00
Subarea B
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Subarea C
0.00
0.00
0.00
0.00
0.00
0.00
Subarea c
0.00
0.00
Unpaved
0. 00
0. 00
Subarea C
0. 00
0.00
0.00
0.00
0.00
0.00
0.00
Peak Weighted Time of
Concentration
days hh:nun:ss
Runoff Curve
cfs Number
3.360
3.36
81.930 0 00:12:40
Analysis begun on:
Analysis ended on:
Thu Apr 08
Thu Apr 08
00:00:01
16:51:32 2010
16:51:33 2010
Total elapsed time:
StormNET Page3
Wonderland Estates 25-Year
BOSS International StormNET® -version 4.14.0 (Build 16362)
****************
Analysis Options
****************
Flow Uni ts ................ cfs
Subbasin Hydrograph Method. SCS TR-55
Time of Concentration ...... SCS TR-55
Pond Exfiltration .......... Constant rate, free surface area
Starting Date ............. FEB-09-2009 00:00:00
Ending Date ............... FEB-10-2009 00:00:00
Report Time Step .....•.... 00:05:00
*************
Element Count
*************
Number of rain gages ...... 1
Number of subbasins ....... 1
Number of nodes ........... 1
Number of links ........... 0
****************
Raingage Summary
****************
Gage
ID
Data
Source
Data
Type
Interval
hours
Gage-1 TS-25 INTENSITY 0.10
****************
Subbasin summary
****************
Subbasin
ID
Sub-1
************
Node Summary
************
Node
ID
Out-9
Total
Area
acres
12.19
Element
Type
OUTFALL
**************************
Runoff Quantity Continuity
**************************
Total Precipitation ..... .
Surface Runoff .......... .
Continuity Error (%)
**************************
Flow Routing continuity
**************************
External Inflow ......... .
External Outflow ........ .
Initial Stored Volume ... .
rinal Stored Volume ..... .
Continuity Error (%)
StormNET
Invert
Elevation
ft
Volume
acre-ft
3.339
0.163
-0.000
Volume
acre-ft
0.000
1.650
0. 000
0. 000
-0.014
97.50
Maximum
Elev.
ft
97.50
Depth
inches
3.287
0.005
Volume
Mgallons
0.000
0.538
0.000
0.000
Ponded
Area
ft'
0. 00
External
Inflow
Page 1
Wonderland Estates 25-Year
******************************************
Composite Curve Number Computations Report
******************************************
Subbasin Sub-1
Soil/Surface Description
Area
(acres l
Soil
Group CN
----------------------------------------------------------------------------------------
Paved parking & roofs
Woods, Good
> 75% grass cover, Good
Composite Area & Weighted CN
***************************************************
SCS TR-55 Time of Concentration Computations Report
***************************************************
Sheet Flow Equation
6.58
1. 30
4. 31
12.19
Tc= (0.007 * {(n * Lf)"0.8)) / ((P"0.5) * (Sf"0.4))
Where:
Tc Time of Concentration (hrs)
n Manning 1 s Roughness
Lf Flow Length (ft)
P 2 yr, 24 hr Rainfall (inches}
Sf Slope (ft/ftl
Shallow Concentrated Flow Equation
V 16.1345 * (Sf'"'0.5) (unpaved surface)
V 20.3282 * (Sf"0.5) (paved surface)
Tc (Lf / V) / {3600 sec/hr)
Where:
Tc Time of Concentration (hrs)
Lf Flow Length (ft)
V Velocity (ft/sec)
Sf Slope (ft/ft)
Channel Flow Equation
V (1.49 * (R"(2/3)) * (Sf"0.5)) / n
R Aq / Wp
Tc (Lf / V) / (3600 sec/hr)
Where:
Tc Time of Concentration (hrs)
Lf Flow Length (ft)
R Hydraulic Radius (ft)
Aq Flow Area ( ft 2 )
Wp Wetted Perimeter (ft)
V velocity (ft/sec)
Sf Slope (ft/ft)
n Manning's Roughness
Subbasin Sub-1
Sheet Flow Computations
StonnNET
B
C
B
98.00
70.00
61. 00
81. 93
Page2
Wonderland Estates 25-Year
Manning's Roughness:
Flow Length (ft):
Slope (%):
2 yr, 24 hr Rainfall (in):
Velocity (ft/sec):
Computed Flow Time (minutes):
Shallow Concentrated Flow Computations
Flow Length (ft):
Slope (%) :
Surface Type:
Velocity (ft/sec):
Computed Flow Time (minutes):
Channel Flow Computations
Manning's Roughness:
Flow Length (ft):
Slope(%):
cross Section Area (ft 2 ):
Wetted Perimeter (ft):
Velocity (ft/sec):
Computed ~low Time (minutes):
Subarea A
0.10
50.00
3.00
2.00
0.19
4.38
Subarea A
200.00
0.50
Paved
1. 4 4
2.32
Subarea A
0.01
1000.00
0.50
1. 00
4.00
2. 79
5.98
Subarea B
o.oc
0.00
0.00
0.00
0.00
0.00
Subarea B
0.00
0.00
Unpaved
0.00
0.00
Subarea B
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Subarea C
o. 00
o. 00
0. 00
0. 00
0. 00
o. 00
Subarea C
0.00
0.00
Unpaved
0.00
0.00
Subarea c
0.00
0.00
0.00
0.00
0.00
0.00
0.00
===========================================================================
Total TOC (minutes): 12.67
~===============================================~==========================
***********************
Subbasin Runoff Summary
***********************
Subbasin
ID
Sub-1
System
Analysis begun on:
Analysis ended on:
Total elapsed time:
StormNET
Total
Precip
in
3.300
3.300
Thu Apr 08
Thu Apr 08
00:00:01
Total
Runoff
in
1. 614
1. 614
Peak Weighted
Runoff Curve
cfs Number
4.510
4.51
81.930
16:52:43 2010
16:52:44 2010
Time of
Concentration
days hh :mm: ss
0 00:12:40
Page 3
Wonderland Estates 100-Year
BOSS International StormNET® -Version 4.14.0 (Build 16362)
****************
Analysis Options
****************
Flow Uni ts .............•.. cfs
Subbasin Hydrograph Method. SCS TR-55
Time of Concentration ...... SCS TR-55
Pond Exfiltration .......... Constant rate, free surface area
Starting Date ............. FEB-09-2009 00:00:00
Ending Date ............... FEB-10-2009 00:00:00
Report Time Step .......... 00:05:00
*************
Element Count
*************
Number of rain gages ...... 1
Number of subbasins ....... 1
Number of nodes ........... 1
Number of links ........... 0
****************
Raingage Swnmary
****************
Gage
ID
Data
source
Data
Type
Interval
hours
Gage-1
****************
Subbasin Sununary
****************
Subbasin
ID
Sub-1
************
Node Summary
************
Node
ID
Out-9
TS-100
Total
Area
acres
12.19
Element
Type
OUTFALL
**************************
Runoff Quantity Continuity
**************************
Total Precipitation ..... .
surface Runoff .......... .
Continuity Error (%)
**************************
Flow Routing Continuity
**************************
External Inflow ......... .
External Outflow ........ .
Initial Stored Volume ... .
Final Stored Volume
Continuity Error {%)
StormNET
INTENSITY
Invert
Elevation
ft
Volume
acre-ft
4.048
0.222
-0.000
Volume
acre-ft
0.000
2.247
0.000
0.000
-0.014
97 .50
Maximum
Elev.
ft
97. 50
Depth
inches
3.985
0.007
Volume
Mgallons
0.000
0.732
0.000
0.000
0.10
Ponded
Area
ft'
0.00
External
Inflow
Page 1
Wonderland Estates 100-Year
******************************************
Composite Curve Number Computations Report
******************************************
Subbasin Sub-1
Soil/Surface Description
Paved parking & roofs
Woods, Good
> 75% grass cover, Good
Composite Area & Weighted CN
***************************************************
SCS TR-55 Time of Concentration Computations Report
***************************************************
Sheet Flow Equation
Area
(acres)
6.58
1.30
4.31
12.19
Tc= (0.001 * ((n * Lf)"0.8)) I ((P"0.5) * (Sf"0.4))
Where:
Tc Time of Concentration (hrs)
n Manning's Roughness
Lf Flow Length (ft)
P 2 yr, 24 hr Rainfall (inches)
Sf Slope (ft/ft)
Shallow Concentrated Flow Equation
V 16.1345 * (Sf"0.5) (unpaved surface)
v 20.3282 * (Sf"0.5) (paved surface)
Tc (Lf / V} / (3600 sec/hr}
Where:
Tc Time of Concentration (hrs)
Lf Flow Length (ft)
v Velocity {ft/sec)
Sf Slope (ft/ft)
Channel Flow Equation
V {1.49 * (RA(2/3)) * (SfA0.5)) / n
R Aq / Wp
Tc (Lf / V) / (3600 sec/hr)
Where:
Tc Time of Concentration {hrs)
Lf = Flow Length (ft)
R Hydraulic Radius (ft)
Aq Flow Area ( ft 2 )
Wp Wetted Perimeter (ft)
V Velocity (ft/sec)
Sf Slope (ft/ft)
n Manning's Roughness
Subbasin Sub-1
Sheet Flow Computations
StormNET
Soil
Group
B
C
B
CN
98.00
70.00
61. 00
81. 93
Page 2
Wonderland Estates 100-Year
Manning's Roughness:
Flow Length (ft):
Slope (%):
2 yr, 24 hr Rainfa~l {in):
Velocity (ft/sec):
Computed Flow Time (minutes):
Shallow Concentrated Flow Computations
Flow Length (ft):
Slope(%):
Surface Type:
Velocity (ft/sec):
Computed Flow Time (minutes):
Channel Flow Computations
Manning's Roughness:
Flow Length (ft):
Slope(%):
Cross Section Area (ft"):
Wetted Perimeter (ft):
Velocity {ft/sec):
Computed Flow Time (minutes):
Subarea A
0.10
50.00
3. 00
2.00
0. 19
4. 38
Subarea A
200.00
0. 50
Paved
1. 44
2. 32
Subarea A
0.01
1000.00
0.50
1. 00
4.00
2. 79
5. 98
Subarea B
0.00
0.00
0.00
0.00
0.00
0.00
Subarea B
0.00
0.00
Unpaved
0.00
0.00
Subarea B
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Subarea C o. 00
o. 00
0. 00
0. 00
o. 00
o. 00
Subarea C
o. 00
0. 00
Unpaved
0. 00
o. 00
Subarea C
0.00
o. 00
0.00
0. 00
o. 00
0. 00
0. 00
-==========================================================================
Total TOC (minutes): 12. 67
-==========================================================================
***********************
Subbasin Runoff Summary
***********************
Subbasin
ID
Sub-1
System
Analysis
Analysis
begun
ended
Total elapsed
StormNET
on:
on:
time:
Total
Precip
in
4.000
4.000
Thu Apr
Thu Apr
< 1 sec
08
08
Total
Runoff
in
2.197
2.197
16:53:44
16:53:44
Peak Weighted
Runoff Curve
cfs Number
6.400 81. 930
6. 40
2010
2010
Time of
Concentration
days hh:mrn:ss
0 00:12:40
Page3
·---------------··-----·---····-···----
HUITI-ZOLLARS, INC. • 814 E. Pi+;e Suet!\ • Seattle, WA 98122-3893 • 205.324.5500 phone • 206.328.1800 fax • huitt-wllars.eom
APPENDIXC:
CONVEYANCE CALCULATIONS
J:\1509320 I\ Wonderland Estates\06\Apri!TIR DRAFT 419/2016
Project Desaiption
Friction Metho<I
SolwFor
Input Data
Results
Discharge
AowAnla -p--
TapWldth
Critical Oepd,
Pen:enl Full
Cri1icll Slope
\lolocity
ValocltyHead
Spaclfic Energy
Froude Number
MaxlmumOischarge
Discharge Full
Slope Full
FlowT-
GVf Input Data
Duwnsb•m Depth
Length
Number Of SIBl)6
GVF Output Data
UpsllNm Depth
Prollle~n --"--End Depth Over RlH
Nomlat Depth OVer RlH
Downslream Velodly
Upstream Valoclty
Worksheet for Circular Pipe -P1-P2-P3
Manning Formula
Discharge
SubCrttical
0.013
0.01000 111ft
0.95 fl
1.00 fl
3.83 11'/o
0.77 ft'
2.69 fl
0.44 fl
0.83 fl
95.0 %
0.01125 111ft
4.97 !tis
0.38 ft
1.33 ft
0.66
3.83 11'/s
3.56 11'/s
0.01155 111ft
0.00 ft
0.00 ft
0
0.00 ft
0.00 ft
0.00 %
95.00 %
Infinity Ills
Infinity Ills
-9-ma.lnc. ---c..ar ---(Ql.01.0M.IO]
117/2010 2:D>IO PII 27 Slamona Company Drl¥8 lllilll 200 W w .... 1Dw1a. CT D87l5 USA +1-203-755-116& Page 1 of 2
GVF Output Data
Normal Depth
Critical Depth
Channel Slope
Critical Slope
1n120to 2:23:ao PM
Worksheet for Circular Pipe -P1-P2-P3
0.95 ft
0.83 ft
0.01000 ft/ft
0.01125 ft/ft
--1ne. ---c.-llenlloyFlowM-r [08-01.oe&.OOI 'D S1emona Company Drift Su1111 200 W Waartown, CT Ol715 USA +1-203-7~1&16 PlilOt 2 of 2
Project Description
Friction Method
Solve For
Input Data
~
FlowAna
WetledPerfmetor
TGI) Width
Crilcal Depth
Pen:en!Ful
Crilcal Slope
Veb:lly
Veb:lly Head
Speclflc Energy
Froude Number
MaJdmLW11 Discharge
Dildlarge Full
Slope Ful
Flow Type
GVF 1...,ut Data
oo,,usbeam Depth
Leng1h
NlmberOfSteps
GVF Output Data
\Jpnam11 Deplh
Profile Descripllon
ProfileHeadloss
A-End Depth 0-Rise
Normal Depth 0-Rise
~Velocity
Upsu-,, Velocity
Worksheet for Circular Pipe • P4 -PS
Manning Formula
Discharge
Sub~
0.013
0.00750 fl/ft
0.95 ft
, .00 ft
3.32 ft'/s
D.77 ft'
2.69 ft
0.44 ft
D.78 ft
95.0 %
0.00956 fl/ft
4.30 ft/o
0.29 ft
1.24 ft
0.57
3.32 ft'/s
3.09 ft'/s
0.00866 fl/ft
0.00 ft
0.00 ft
0
0.00 ft
0.00 ft
0.00 %
95.00 %
Infinity ft/s
Infinity ft/o
__ ... _____ --(Oll.01.DIIJIO]
,mano 11: ... :22 AM 27 Silmone Company~ Sutte 200 W WalelloWn, CT 067l5 USA •1-203-755-1111 Page 1 of 2
GVF Output Data
Normal Deplt,
Crltlcal Depth
Channel Slope
CriHoal Slope
Worksh-t for Circular Pipe -P4 • f5
0.95 ft
0.78 ft
0.00750 ft/ft
0.00956 ft/ft
a.nu.,.,..._, Inc. HaNtacl llalhod:I Solution Center a.nuey FloMfl 1 (OI.D1.Gl6.GO)
27SiernonaCompanyDr1wSulte200W Watertown,CTOITISUSA •1-203-75S-1tN Page 2 of 2
. ! i i .';
HUITI-ZOLLARS, INC. • B14E. Pike Street Seattle. WA 98122-3893 • 2063245500phone • 206.328.1880fax • hultt·zolla-s.com
APPENDIXD:
ALTERNATIVE DRAINAGE PROPOSAL
J:\1509320 I\ Wonderland Estales\06\Apri!TIR DRAFT 4/9/2011J
Denis Law
Mayor
April 2, 2010
Don Helling
Huitt-Zollers
814 E Pike Street
Seattle, WA 98122
SUBJECT: "On Hold" Notice
r
_!
_ Cityof 1 _ _ ___ _ -µ·r1·r.011
Department of Community and Economic Development
Alex Pietsch, Administrator
RECEIVED
APR 05 2010.
HUIIT·zou.ARS
SEAT11.E
Wonderland Estates Utility Replacement, LUAl0-008, ECF, CAR
Dear Mr. Helling:
Thank you for submitting the updated TIR as requested in the March 8, 2010 Hold Letter. After
review of the new materials staff has identified some additional areas of concern as described
below:
1. As proposed, a•'.::litional stormwater would be diverted from its currant drainage
location of-Madsen Creek into a new stream tributary identified in the provided TIR as
"Stream A". Stream 'A' flows through the City's Ron Regis Park and eventually outfalls
into the Cedar River. A. Biological Impact Assessment Memo completed· by the
Watershed · Company was provided in Appendix E of the TIR report .. Within this
Assessment,. The Watershed Company indicates that no wetlands were observed along
Stream A: The City believes this report is in error,because a wetland was identified in
this area during the Cedar River Regional Park Master Pl.in process. The diversion cf
additional stormwater, to this wetland, may have adverse impact to the wetland
hydrology, The additional. storm water runoff could result.in an increase in the wetland
size and/or value affectively increasing its .buffer size and/or area.. If the wetland
changes in size and/or value it would have adverse impacts on the Cedar River Regional
Park Master Plan and anticipated improvements for Ron Regis Park. Furthermore, the
City has received grant funding for Ron Regis Park from the Recreation and Conservation
Office (RCO) and the Federal Land and Water Conservation; these grant funds require
that particular in,provements are made to the Park. Changes to the wetland or Stream
'A' may impact the City's ability to comply with the grant funding requirements.
2. Additionally the City is wor-king with potential FEMA funds to rehabilitate the Elliot
Spawning channel that was damaged in the 2006 and 2009 Cedar River flooding events.
The Elliot Spawning channel is located just downstream of point F of Stream 'A', as
Renton City Hall • 1055 South Grady Way • Renton, Washington 98057 • rentonwa.gov
Mr. Don Helling
April 2, 2010
Page2of3
identified in the TIA. Any increase in Stream flows may affect the City's access to the
site during construction as well as potentially impact the spawning channel itself.
In addition to the above concerns, the City Stormwater Division has questions and/or concerns
about the provided TIA. The following is a list of issues identified by the City's Stormwater
Division:
1. The TIR states that discharging site runoff to the northwest-corner of the site would
alleviate flooding in Wonderland Estates and reduce some of the flooding potential
in Lower Madsen Creek. The TIR does not quantify how much flooding would be
reduced. It would seem that removing 3 cfs from the total tributary flow to Madsen
Creek would have negligible improvement in the amount ofon site flooding.
2. The Storm,•,ater Division is confused with Table 3.1 on page 13. U11der existing
conditions for the 25-yr storm, Wonderland Estates contributes 452 CFS. Is this
because the pumps do not have enough capacity to pump the on site runoff to
Madsen Creek? What if the pumps were sized to discharge all the site runoff to
Madsen Creek. What would be the amount of increased flooding that would occur
at the northwest corner ofthe site?
3. Why is the proposed flow for the 25-yr event 3 cfs for Wonderland Estates in Table
3.1? One would think the proposed flow should be 4.52 cfs + 3.0 cfs or 7.52 cfs,
which is the capacity ofthe conveyance system of the proposed discharge route.
4. The Stormwater Division doesn't understand how the existing -water surface
elevations for Stream A at points A, B, C, D, E and F are higher than the proposed
conditions. The proposal to divert additional flow to Stream 'A' will add 3.cfs for the
25-yr event; therefore, the water surface elevations must increase correspondingly.
Table 3.2 shows the 2.5-yr design flow of 10.33 cfs for existing conditions and 8.81
cfs for proposed conditions. How can this be when additional flow is being diverted
to Stream 'A'?
5. The project does not trigger flow control because the proposed improvements will
not result in an increase in impervious surface; however, because Stream 'A' is
located in an area with eroaible soils, any increase in flow could result in erosion and
subsequent degradation of water quality. To eliminate this condition, the proposal
to divert flows would require that Stream 'A' be placed in a pipe all the way to the
Cedar River. Constructing a pipe through a wetland is not allowed per City code.
Code would require that the pipe be placed in an alignment that avoidsthewetland.
Placing Stream 'A' in a pipe would change the hydrology of the wetland by reducing
the volume oftributary runoff and would require an analysis determine any impacts
and appropriate mitigation. Finally, constructing the pipe near a sensitive area
would involve federal, state and local permits.
'
Mr. Don Helling
April 2, 2010
Page 3 of 3
Based on the above-identified technical issues and concerns the City requests that the applicant
look at alternative drainage discharge locations that would not result in impacts to City Parks,
grant funding, and spawning channel.
At this time, your project has been placed "on hold" pending resolution of the drainage
concerns and issues identified -above. Please contact me at (425) 430-7314 if you have any
questions or would like to schedule a meeting to discuss the identified project issues.
Sincerely,
Vanessa Dolbee
(Acting) Senior Planner
Enclosure: Ron Regis Park Wetland Study and Dellne~ion Maps
cc: King County Housing Authority· Hugh Watkinson/ Owner(s)
leslle.Betlach, Parks Planning and Natural Resources Director
Allen (luynn, Civil Engineer
Arneta HE!nnlnger, Plan Reviewer
1?~ R~~1s PA-~/(_
WETLAND STUDY
CEDAR RIVER REGIONAL PARK
RENTON, WASHINGTON
Prepared for:
JongeJan•Gerrard•McNeal
23 103rd Avenue Northeast
Bellevue, Washington 98004
Prepared by: ·
The Watershed Company
10827 Northeast 68th Street, Suite B
Kirkland, Washington 98033
January 12, 1993
Introduction
The site of the proposed Cedar River Regional Park is located along the Maple Valley Highway
(SR 169) east of downtown Renton, on the Cedar River between Maplewood Golf Course and
Jones Road, Township 23N, Range 5E, Section 22. A wetland study was completed for the
property, Including delineation of a large wetland adjacent to the Cedar River.
Methods
Wetland dellneetlon was preformed according to the 1989 Federal Manual for Identifying and
OellneeUng Jurisdictlonal Wetlands. Vegetation, soils, and hydrology were examined. In order
to make a determination of the presence of wetland, Indicators of hydrophytic vegetation, hydrio
soil, and wetland hydrology must be observed. Hydrophytlc vegetation consists of a plant
community In which more than 50% of the dominant species have a we11and indicator status
(Reed, 1988) of facultative (FAC), facultative wetland (FACW), or obligate (OBL). Soll color
In hand dug test pits was used as an indicator of hydric son. A chroma of one, or of two in
mottled soll, Is considered Indicative of hydric soil. Wetland hydrology is present when soll is
saturated to the surface for at least one week during the growing season.
Results
A single wetland was identified on the site. The wetland boundary roughly parallels the Cedar
River, dividing the site Into upland on the south portion of the property, and wetland on the
north portion. The wetland is forested, and inciudes a small beaver pond formed on Madsen
Creek; this stream runs along the eastern property boundary. ·
YtOetatinn
Vegetation of the south part of the site has been disturbed in the past, and now consiSts mainly of
cl1.1mp5 of blackberries along with grasses and other weedy plants. Species present include
Himalayan and evergreen blackberry, Scot's broom, bull and Canada thistle, buckhorn plantain,
clover, Watson's willow-herb, common tansy, and grasses such as orchard grass, quackgrass,
and bentgrass. These species do not constitute hydrophytlc vegetation, as less than 50% of the
dominant species have a wetland lndlc:alor status of FAC, FACW, or DBL At the southern
property boundmy, near lhe railroad right of way adjacent to Maple Valley Highway, some red
alder trees form a line; a shrub thicket consisting of snowberry and Pacific ninebark borders a
ditch next to the right of way. To the north, In the vicinity of the wetland boundary, the
dominant species Include Himalayan blackberry, evergreen blackberry, soft rush, reed
canarygrass, field horsetail, bulrushes, creeping buttercup, and ground ivy.
In the forested portion of the wetland, a variety of plant species are present. In the overstory,
the dominant trees are red alder, black cottonwood, bigleaf maple, and western red cedar;
several trees are dying due to flooding caused by beavers. Pacific willow and Engllsh holly ere
also present. Understory species include snowberry, salmonberry, nootka rose, ninebark, reed
cana,ygrass, piggyback, curly dock, buttercup, and bulrushes. Because more than 50% of these
species have an Indicator status of FAC, FACW, or OBL, this plant community is considered
hydrophytic.
1
The on·site soils have been mapped In the King County Soil Survey as Newberg silt loam,
Puyallup fine sandy loam, and Riverwash. Of these soUs, only Riverwash is considered hydric;
the northern part of the site, along the Cedar River, was mapped as Riverwash.
SOIi colors vary relatively little across the site. On the upland part of the site, the colors
typically found were olive brown (2.5 Y 4/3) and brown (1 a YR 4/3), primarily without
mottles. Soll color within the wetland was generally dark grayish brown (2.5 Y 4/2) or very
dark grayish brown (2.5 Y 3/2) with mottles. These colors meet the criterion for hydric soil.
Hydmlooy
Because fiek:I work was conducted in Oecember, soils throughout the site were damp to saturated.
The transition between damp and saturated soils, moreover, was a fairly reliable indicator of
the wetland boundary. That Is, at the lime of obsetVatiQn, soil within lhe. wetland was nearly all
saturated, meeting the criterion for wetland hydrology. Ponded water was observed in many
areas, Including a small beaver pond.
Madsen Creek constitutes another hydrologlc feature of the site. The stream was relocated onto
the slte by King County Surface Water Management. In its current channel, it enters the
property at the southeast corner, follows the eastern property boundary, then flows through the
weUand to the Cedar River. The stream was not field-flagged, as there is no wetland fringe on
the edges of the stream.
In add'ition, a small drainage with wetland characteristics Is present on the western property
boundary. This drainage was delineated and flald-llagged as wetland.
The hydrology of the area Is likely lo be changing due to the activity of be ave rs. A dam has been
constructed on Madsen Creek, creating a small pond, and recent activity is evident. Because of
the presence of beavers, the location of the wetland boundary may change In the future.
Summery of Existing Condmons
The site of the proposed Cedar River Regional Park was screened for the presence of wetlands. A
single wetland was Identified and fteld-flagged; this wetland encompasses most of the northern
part of lhe site, adjacent to the Cedar River. No other wetlands are present on the property.
The values of the delineated wetland include wildlife habitat, water quality, and flood oontrol.
Due to the proximity of the Cedar River, the wetland Is expected to play a significant role in
attenuation of flOods in the area. II also serves as a filter to improve water quality.
Moreover, the site has tremendous value tor wildHfe, particularly the northern portion of the
sue wh lch Includes the forested wetland. With the combi"lation of the presence of the river,
mixed forest, shrub, open water (pond), and grassland habitat, the site provides not only
dwerse habitat types but a large amount of edge habitat. Edges are important for wildltfe as
they support a particularly diverse plant community within a short distance.
The site can be expected to support a variety of bird species, including songbirds, ground birds,
2
woodpeckers, and raptors, as well as small mammals, deer, furbearers, reptiles, and
amphibians. Bird species observed Include the black-capped chickadee, American goldfinch,
rufous-sided towhee, song sparrow, Lincoln's sparrow, purple finch, varied thrush, golden-
crowned kinglet, ruby-crowned kinglet, American robin, winter wren, Northern flicker,
downy woodpecker, California quaff, red-tailed hawk, sharp-shinned hawk, American kestrel,
mallard, goldeneye, common merganser, and great blue heron. Other wildlife detected Include
the beaver, raccoon, and black-tailed deer.
Under the Renton Wetlands Management Ordinance, the wetland is considered a Category I
wetland, due to Its size (approximately 21.5 acres) and the presence of three vegetation
classes, one of which Is open water. Because the wetland wffl be preserved as the site Is
developed, wllclllfe will continue to use the wetland. Moreover, use of the property as a park
will enhance public access to the area, !hereby contributing to enjoyment of the resource.
3
Common Name
PYerstocvarees:
red alder
big leaf maple
English holly
black cottonwood
Pacific willow
sltka willow
western red cedar
SbruhstYlnes ·
butterfly bush
red osier dogwood
nlnebark
nootka rose
Himalayan blackbetry
evergreen blackberry
blackcap raspberry
thlmbleberry
salmonberry
tralllng blackberry
snowberry
GmundCOYer
quackaress
bentgrass
lady fem
bull thistle
Canada thistle
morning glory
Scotch broom
orchard grass
foxglove
Watson's willow herb
field horsetail
soourlng rush
leacue
large-leaf evens
wild geran lu m
ground Ivy
English ivy
St. John's wort
soft rush
toad rush
(iJd(weed
reed canary grass
Table I: Plant Species Observed
Scientific Name
A/nus rubra
Acer macrophyllum
/lex aquifollum
Populus trichocarpa
Salix lasiandra
Salix sitchensis
Thuja plicata
Budcileia davidii
Cornus stolonlfera
Physocatp(JS cspltatus
Rosa nutkana
Rubus discolor
Rubus lacinatus
Rubus lel}(;Odermis
Rubus pstYiflorus
Rubus spectabHis
RI/bus ursinus
Symphorocarpus a/bus
Agropyron repens
Agrostis spp.
Athyrium flllx-femlna
Clrsium vulgare
Cirsium arvenss
Convolwlus sepium
Cytisus scoparius
Dactylis glomerata
Digitalis purpureum
Epi/oblum watsonn
Equisetum arvense
Equisteum /aevigatum
Festuca spp.
Geum macrophyllum
Geranium spp.
GJecoma hedetaCea
Hedera hellx
Hypericum perforatum
Juncus effu6/Js
Juncus bufonlus
Lemna minor
Phsla.rls srundinacea
Indicator Status
F>C
Fh:::t.J
NL
00
FACW+
F/CN
00
NL
FICH
FAC+
NI
FACU·
FACU+
NL
FACU+
FftC
NL
FAru
FACU
FACW-FACU, NI
nllC
FH)J
FACU+
NL
NL
FAOJ
NL
03l
F/CN
FH:m
FAC,FACU
FACt
FAU+
FAClJ.t
NL
NL
F/CN
FACW+
OBI.
FK/N
common plantain
licorlce fern
Japanese bamboo
sword fern
bracken fern
creeping buttercup
curly clock
small fruited bulrush
bittersweet nightshade
common tansy
piggyback plant
white clover
cattail
stinging nettle
American brooklime
vetcll
Table I: Plant Species Observed (cont.)
Plantago major
Po/ypody spp.
Polygonum cuspidawm
Polystichym munitum
Pteridium aquilinum
Ranuncu/us repens
Ru111Bx crlspus
Scirpus microcarpus
Sohmum dulcamara
Tanacetum vu/gare
Tolmiea menzlesii
Trifolium repens
Typha latitolia
Urtica dloica
Veronica amerlcana
V",cia spp.
FAC+
NL
NI
NL
FACU
F,C:W
FKJN
ca.
00
NL
00
FAClJ
ca
FAC+
ca.
NJ
Table II: Soil Test Pits
son e11 # Matrix Color Motlle Color Hydrology Weuand Deteuuioatlon
1 10 YR 3/2 Yes Damp No (fill)
2 10 YR 413 N:) Damp N:>
3 ·10 YR 4/3 N:) Damp N:)
4 10 YR 4/3 N:) Daill) fib
5 10 YR 3/2 Yes Dan1J Yes
8 2.5 Y 3/3 N:) Damp N:)
7 10 YR 4/2 N:) Damp N)
8 2.5 Y 4/3 N:) Damp N:)
9 2.5 Y 4/2 Yes Saturated Yes
10 10 YR 3/2 N:> Damp N)
11 10 YR 4/2 N:) Damp N)
12 10 YR 4/3 Yes Damp No
1S 10 YR 3/2 N:) Damp N)
14 10 YR 4/3 N:) D amp fib
15 2.5 Y 4/2 5 YR 4/8 Nearly Saturated Yes
18 2.5 Y 3/2 Yes Nearly Saturated Yes
17 2.5 Y 4/3 Yes Nearly Saturated Transition
18 10 YR 4/3 N:) Damp N:)
19 2.5 Y 4/3 N:) Damp N)
20 10 YR 3/3 N:) Damp N:)
21 · 2.5 Y 3/2 Yes Very Damp Yes
22 2.5 Y 4/3 N:) Very Damp Transition
23 2.5 Y 4/2 Yes Saturated Yes
24 5 Y S/2 Yes Saturated Yes
25 2.5 Y 4/3 N:> Damp N:,
26 2.5 Y 4~ Yes Damp Transition
27 2.5 Y 4/3 N:> Damp N:>
28 2.5 Y 4/3 N:> Damp N:>
29 . 2.5 Y 3/2 NJ Damp Transition
30 10 YR 3/2 Yes PQK:lecj Yes
31 2.5 Y 3/2 Yes Saturated Yes
32 10 YR 3/2 N:> Damp Transition
33 2.5 Y 412 Yes Damp Yes
34 2.5 Y 4/3 N;, Damp N:)
35 2.5 Y 4/3 N;, Damp N:)
36 2.5 Y 4/3 N;, Damp N:>
37 2.5 Y 3/3 Yes Damp N;,
38 10 YR 3/2 N;, Damp N:)
39 . 2.5 Y 4/2 7.5 Y 4/6 Damp N;,
40 2.5 Y 4/3 N:) Datnp N:>
'
REFERENCES
cowardln, Lewi$ M., Virginia Carter, Francis C. Goist, and Edward T. LaRoe. 1979.
Classification of Wetlands and Deepwater Habitats of the United States. U.S. Department of the
Interior, Fish and WIidiife Service. FWS/OBS 79/31. 103 pages.
Federal lnteragency Committee for Wetland Delineatlon. 1989. Federal Manual for Identifying
and Dellneatlng Jurisdictional Wetlands. U.S. Army Corps of Engineers, U.S. Environmental
PrOtaction Agency, U.S. Fish and Wlk:lllfe Service, U.S.O.A. Soi Conservation Service.
Washington, o.o. Cooperative technical publlcatlon. 76 pp. plus appencfices.
Munsell Color. 1990. Munsell Soll Color Charts. Macbeth Division of Kollmorgen Instruments
Corporation, Baltimore, Maryland.
Reed, Porter B., Jr, 1988. National List of Plant Species That Occur in Wetlands: 1988,
Washington. U.S. Department of the Interior, Fish and Wildlife Service. NERc-88118.47.
Soll Conservation Service, 1973. Soll Survey, King County Area, Washington. U.S.
Department of Agriculture. 100 pages.
AREA T._,rALS:
PROJECT SITE -45 ACRES
WETLAND -21.5 ACRES
/ ,,::>;;:C_;:;--~:;-··-~:::,,
TOT AL. BUFFER -5.7 ACRES '247,000 S.F.)
BUFFER
----EXISTING "FOOTPATH
FOR "FISHING ACCESS
PROPOSED SOFT
SURFACE PATH
EXISTING~
TREE! CANOPY I
"L.EXISTING ~ND AREA
lFROM ~OUNDARY TO ·RIVERI l
~ ...-=::::'! PROPOSED S -~~ ~---:~ SURFA OFT
J:]~~ -"'-J? CE PATH
=--~:~:L?/ ~XISllNG . ~
OPEN WATER _..__
··-~--'-.,'":::-:·; _-:, =
/ PROPOSED 285'
SOFTBALL
~PiOPOSEO RESTROOM~
:· NCESSION/SUf'ERVl~OR/
~ .. _\ ·i f:"ih]3 'x~1MENT STORAGE
PROe:o~·o
socffi FIELD
360'x225'
.. , e _J:i
:----.
~
' .
. PROPOSED 285'
SOFTBALL
I,
~
' r·.-.
fcHAfMAt(
IJ.IFE ..
jE~TA°iF
'
.i -
z··, ::q
Cl:UAH HJVl:H
REGIONAL PARK
RENTON .PARKS Ii RECREATION
SCHEMA TIC PLAN
JANUARY 11,, 1H4
.lc»:C£(.,o.l,l•~•NoNE,,,.1. __ ... --.---.. ---··----. ··-.,;;:, -"~v ... -~
,,,
"( \
\ \
' ' .------·----·./
L
---------~ r·--"~------·--
= 1 • EX1ST1HG
_.5p:~. STRUCTURE 50' ACCESS
EASEMENT I _i 00..,. .. ,...,..er
!i
~
" ---!! -·21
OSED
rENANCE
AGE
::.-: =-==---=--.--:..::..-:=..:: :--=....-.-=-.=..-:: ~ := =: ~-~ ::.SR-1ss MAPLE VALLEY tflG1-1WAY ~.:.:--=------.-~WE:lciHTSr-ATiON= =: ~CEDAR RIVER. T~~ _1!"SOOTI: ==--=..=. = = = = = ==: !-~~'-~--~~T_.!=!'.~~~~--
+
+
• ll
.,. ,.
\~
1,
• ' J>
G
" ·-+ l" ,. ·-~,
•
+ +
' 8
~ I . , + +
' 'l 8
+
I h ' 1 ~ 0
I A
' ,j. +
l • z
,f
s 8
' '