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Western Washington Division Eastern Washington Division
165 NE Juniper St., Ste 201, Issaquah, WA 98027 407 Swiftwater Blvd., Cle Elum, WA 98922
Phone: (425) 392-0250 Fax: (425) 391-3055 Phone: (509) 674-7433 Fax: (509) 674-7419
www.EncompassES.net
PRELIMINARY TECHNICAL INFORMATION REPORT
for the
28Hundred Unit Lot Subdivision
February 20, 2017
Revised January 21, 2018
Revised April 10, 2018
Encompass Engineering & Surveying Job No. 16663
Prepared For:
Yves Tang
Greystoke LLC
720 North 10th Street #A282
Renton, WA 98057
28Hundred Preliminary Technical Information Report
April 10, 2018 Page i
TABLE OF CONTENTS
I. PROJECT OVERVIEW .......................................................................................................... 1
II. CONDITIONS AND REQUIREMENTS SUMMARY .......................................................... 3
III. OFF-SITE ANALYSIS ............................................................................................................ 5
IV. FLOW CONTROL, LOW IMPACT DESIGN (LID) AND WATER QUALITY FACILITY
ANALYSIS AND DESIGN .................................................................................................... 8
VI. SPECIAL REPORTS AND STUDIES .................................................................................. 20
VII. OTHER PERMITS ................................................................................................................ 20
VIII. CSWPPP ANALYSIS AND DESIGN .................................................................................. 20
IX. BOND QUANTITIES, FACILITY SUMMARIES, & DECLARATION OF COVENANT 20
X. OPERATIONS AND MAINTENANCE MANUAL ............................................................ 20
Appendix A Infiltration Evaluation .............................................................................................. 21
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 1
I. PROJECT OVERVIEW
Project: 28Hundred Unit Lot Subdivision
Tax Parcel #: 722780-1690 & 722780-1695
Site Addresses: 2800 NE 12th St & 2801 NE 13th ST
Zoning: R-14
Site Area: The project area is 0.66 Acres
Site Location: The site is on the east side of Harrington Avenue NE between NE 12th Street and NE
13th Street
Project Description: This project involves developing a 0.66-acre parcel into an 11-unit, Unit Lot
Subdivision.
Site Plan
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 2
Existing Adjacent Development:
Existing development adjacent to the subject site includes the following:
North – Single Family Residences and NE 13th Street
East – Single Family Residences
South – Single Family Residences & NE 12th Street
West – McKnight Middle School & Harrington Avenue NE
Pre-developed Site Conditions:
The project site presently consists of two parcels totaling 0.66 acres with existing houses/garages
with sidewalks and driveways—the remaining area is covered with sparse mature trees with lawn.
The site generally slopes down from the north to south at approximately 1%.
Critical Areas: No onsite critical areas.
Soils: Per the SCS soil maps, the site is underlain with Arents, Alderwood, gravelly sandy loam (AmC)
soil. Per Geotech report prepared for this project, “Infiltration Evaluation Proposed Harrington
Glade Townhomes 2800 Northeast 12th Street Renton, Washington”, dated August 1, 2014, and
prepared by Earth Solutions NW, the site is underlain with at least 8’ – 14’ of silty sand, infiltratable
soil. The soil is suitable for infiltration BMPs.
Post-developed Site Conditions:
The proposal incorporates the construction of frontage improvements along NE 13th Street together
with water/sewer/storm for an 11-unit Unit Lot Subdivision. The existing single-family residences
will be removed.
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 3
Vicinity Map
II. CONDITIONS AND REQUIREMENTS SUMMARY
Core Requirement #1: Discharge at the Natural Location
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 4
The proposed on-site drainage patterns emulate those of the existing site conditions:
infiltrating into the onsite soil, and running off to the south into the existing City storm system. A
detention facility will provide flow control and water quality, outfalling into the City storm system.
Infiltration for the building roofs will provide the required BMPs.
Core Requirement #2: Off-site Analysis
See Section III.
Core Requirement #3: Flow Control Facilities
Flow control will be provided for the development with a detention only stormwater vault.
See Section IV for a conceptual design using WWHM2012.
Core Requirement #4: Conveyance System
Conveyance and capacity analysis of the new proposed system will be presented with the
final drainage report.
Core Requirement #5: Construction Stormwater Pollution Prevention
A Construction Stormwater Pollution Prevention plan, which will serve to minimize soil
erosion/sedimentation during the proposed site construction, will be prepared for the final
engineering plans.
Core Requirement #6: Maintenance & Operations
The on-site storm water system will be maintained by the Unit Lot Subdivision HOA.
Maintenance & operations documentation will be provided with the final drainage report.
Core Requirement #7: Financial Guarantees & Liability
The owner will arrange for any financial guarantees and liabilities required by the permit.
Core Requirement #8: Water Quality
Because there will be greater than 5,000 sq-ft of new PGIS, water quality measures will be
provided with a Filterra biofiltration device w/presedimentation chamber and/or Vortechs
hydrodynamic separator providing enhanced water quality treatment.
Core Requirement #9: Flow Control BMPs
Dispersion is not feasible because this site will be largely covered with buildings and
driveway. Flow control BMPs will be provided with infiltration trenches for the building
roofs.
Special Requirement #1: Other Adopted Area-Specific Requirements
None
Special Requirement #2: Flood Hazard Area Delineation
None
Special Requirement #3: Flood Protection Facilities
None
Special Requirement #4: Source Control
Source control is not required for this project.
Special Requirement #5: Oil Control
Oil control is not required for a residential subdivision, it doesn’t qualify as a high-use site.
Special Requirement #5: Aquifer Protection Area
This site is located in in Zone 2 of the Aquifer Protection Area. Because we are not
proposing open stormwater facilities or ditches, this project meets the Zone 2 Aquifer
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 5
Protection Area restrictions/requirements.
III. OFF-SITE ANALYSIS
Location: Tax Parcel #: 722780-1690 & 722780-1695
Site Addresses: 2800 NE 12th St & 2801 NE 13th ST
Site Location: The site is on the east side of Harrington Avenue NE between NE 12th Street and NE
13th Street
Project Description: This project involves developing a 0.66-acre parcel into a 12-unit, Unit Lot
Subdivision. The project site presently consists of two parcels totaling 0.66 acres with existing
houses/garages with sidewalks and driveways—the remaining area is covered with several mature
trees with lawn. The site generally slopes down from the north to south at approximately 1%.
Soils: Per the SCS soil maps, the site is underlain with Arents, Alderwood, gravelly sandy loam (AmC)
soil. Per Geotech report prepared for this project, “Infiltration Evaluation Proposed Harrington
Glade Townhomes 2800 Northeast 12th Street Renton, Washington”, dated August 1, 2014, and
prepared by Earth Solutions NW, the site is underlain with at least 8’ – 14’ of silty sand, infiltratable
soil.
Existing Upstream Drainage
Little if any upstream areas drain to this site.
Existing Downstream Drainage
Any runoff from the site sheet flows southwest and enters into street gutter which drains into public
storm drainage system—a CB at point (A) which is located in the intersection of NE 12th St and
Harrington Ave NE. From there flow drains southwest through a 6-inch Conc. pipe into a CB type II-
MH per survey field and per city of Renton (GIS) records at point (B). From point (B) flow also drains
southwest through a 24-inch CMP pipe into another CB type II-MH at point (C). From there flow
drains west along the NE 12th St through a 36 -inch pipe to another CB type II-MH at point (D) for a
total of 120-feet downstream from the site. From point (D) flow continues west through a 36-inch
pipe to another CB at point (E) per city of Renton records. Form there flow drains through a 36 -inch
pipe to another CB type II-MH at point (F) for a total of approximately 470-feet down stream. From
there flow drains through a 36-inch pipe to another CB type II-MH at point (G). From there flow
drains through a pipe to another CB type II-MH at point (H) located on intersection of NE 12th St
and Edmonds Ave NE for a total of approximately 800-feet from the site. From point (H) flow
continues south along Edmonds Ave NE through an 18-inch pipe to another CB type II-MH at point
(I). From there flow continues south through an 18 -inch pipe to another CB at point (J). From Point
(J) flow drains through another 18-inch pipe to another CB at point (K) for a total of approximately
1100-feet downstream from the site. From there pipe continues south (L) to ¼ mile downstream
from the site and enters into public storm drainage system along the NE Sunset Blvd. Eventually the
runoff discharges into Lake Washington.
There were no obvious downstream drainage problems.
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 6
Photo 1: Looking South from Harrington Ave NE/NE 13th St.—Subject property on the left
Photo 2: Intersection of Harrington Ave NE & NE 12th St.—CB at point (A)
28Hundred Preliminary Technical Information Report
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Photo 3: looking west from NE 12th St. towards intersection of Edmonds Ave NE
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IV. FLOW CONTROL, LOW IMPACT DESIGN (LID) AND WATER QUALITY FACILITY
ANALYSIS AND DESIGN
Performance Standards
The site was analyzed using the WWHM2012 software. A detention only vault, together with a
Filterra biofiltration device w/presedimentation chamber and/or Vortechs hydrodynamic separator
will provide the required flow control and enhanced water quality treatment.
Existing Conditions
A = Parcel Area = 28,694 sq-ft = 0.66 acres
Ap = 0.66 acres (C soil woods)
Ai = 0.0 acres (impervious)
Developed Conditions
A = 0.66 acres
Ai-roof = 8,843 sq-ft = 0.20 acres (roofs)
Ai-driveway= 6,585 sq-ft = 0.15 acres (driveway)
Ai-sw = 2,366 sq-ft = 0.05 acres (on and offsite sidewalks)
(0.40 acres impervious)
Ap = 0.66 – 0.40 = 0.26 acres (C soil lawn)
Vault Design
Live Storage Depth = 9’
Using WWHM2012, required live storage volume = 8,944 cu-ft (see printout below)
A vault with inside dimensions of 10.1’ X 100’ with a live storage depth of 9’ will provide the
required volume.
WWHM2012
PROJECT REPORT
___________________________________________________________________
Project Name: 28Hundred
Site Name: 28Hundred
Site Address: 2800 NE 12th St
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 9
City : Renton
Report Date: 2/23/2018
Gage : Seatac
Data Start : 1948/10/01
Data End : 2009/09/30
(adjusted) Precip Scale: 0.00
Version Date: 2016/02/25
Version : 4.2.12
___________________________________________________________________
Low Flow Threshold for POC 1 : 50 Percent of the 2 Year
___________________________________________________________________
High Flow Threshold for POC 1: 50 year
___________________________________________________________________
PREDEVELOPED LAND USE
Name : Basin 1
Bypass: No
GroundWater: No
Pervious Land Use acre
C, Forest, Mod .66
Pervious Total 0.66
Impervious Land Use acre
Impervious Total 0
Basin Total 0.66
___________________________________________________________________
Element Flows To:
Surface Interflow Groundwater
___________________________________________________________________
MITIGATED LAND USE
Name : Basin 1
Bypass: No
GroundWater: No
Pervious Land Use acre
C, Lawn, Mod .26
Pervious Total 0.26
Impervious Land Use acre
ROOF TOPS FLAT 0.2
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 10
DRIVEWAYS FLAT 0.15
SIDEWALKS FLAT 0.05
Impervious Total 0.4
Basin Total 0.66
___________________________________________________________________
Element Flows To:
Surface Interflow Groundwater
Vault 1 Vault 1
___________________________________________________________________
Name : Vault 1
Width : 9.9681275598235 ft.
Length : 99.681275598235 ft.
Depth: 10 ft.
Discharge Structure
Riser Height: 9 ft.
Riser Diameter: 18 in.
Orifice 1 Diameter: 0.4 in. Elevation: 0 ft.
Orifice 2 Diameter: 0.65 in. Elevation: 5.913 ft.
Orifice 3 Diameter: 0.39 in. Elevation: 6.66 ft.
Element Flows To:
Outlet 1 Outlet 2
___________________________________________________________________
Vault Hydraulic Table
Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs)
0.0000 0.022 0.000 0.000 0.000
0.1111 0.022 0.002 0.001 0.000
0.2222 0.022 0.005 0.002 0.000
0.3333 0.022 0.007 0.002 0.000
0.4444 0.022 0.010 0.002 0.000
0.5556 0.022 0.012 0.003 0.000
0.6667 0.022 0.015 0.003 0.000
0.7778 0.022 0.017 0.003 0.000
0.8889 0.022 0.020 0.004 0.000
1.0000 0.022 0.022 0.004 0.000
1.1111 0.022 0.025 0.004 0.000
1.2222 0.022 0.027 0.004 0.000
1.3333 0.022 0.030 0.005 0.000
1.4444 0.022 0.032 0.005 0.000
1.5556 0.022 0.035 0.005 0.000
1.6667 0.022 0.038 0.005 0.000
1.7778 0.022 0.040 0.005 0.000
1.8889 0.022 0.043 0.006 0.000
2.0000 0.022 0.045 0.006 0.000
2.1111 0.022 0.048 0.006 0.000
2.2222 0.022 0.050 0.006 0.000
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April 10, 2018 Page 11
2.3333 0.022 0.053 0.006 0.000
2.4444 0.022 0.055 0.006 0.000
2.5556 0.022 0.058 0.006 0.000
2.6667 0.022 0.060 0.007 0.000
2.7778 0.022 0.063 0.007 0.000
2.8889 0.022 0.065 0.007 0.000
3.0000 0.022 0.068 0.007 0.000
3.1111 0.022 0.071 0.007 0.000
3.2222 0.022 0.073 0.007 0.000
3.3333 0.022 0.076 0.007 0.000
3.4444 0.022 0.078 0.008 0.000
3.5556 0.022 0.081 0.008 0.000
3.6667 0.022 0.083 0.008 0.000
3.7778 0.022 0.086 0.008 0.000
3.8889 0.022 0.088 0.008 0.000
4.0000 0.022 0.091 0.008 0.000
4.1111 0.022 0.093 0.008 0.000
4.2222 0.022 0.096 0.008 0.000
4.3333 0.022 0.098 0.009 0.000
4.4444 0.022 0.101 0.009 0.000
4.5556 0.022 0.103 0.009 0.000
4.6667 0.022 0.106 0.009 0.000
4.7778 0.022 0.109 0.009 0.000
4.8889 0.022 0.111 0.009 0.000
5.0000 0.022 0.114 0.009 0.000
5.1111 0.022 0.116 0.009 0.000
5.2222 0.022 0.119 0.009 0.000
5.3333 0.022 0.121 0.010 0.000
5.4444 0.022 0.124 0.010 0.000
5.5556 0.022 0.126 0.010 0.000
5.6667 0.022 0.129 0.010 0.000
5.7778 0.022 0.131 0.010 0.000
5.8889 0.022 0.134 0.010 0.000
6.0000 0.022 0.136 0.014 0.000
6.1111 0.022 0.139 0.015 0.000
6.2222 0.022 0.141 0.017 0.000
6.3333 0.022 0.144 0.018 0.000
6.4444 0.022 0.147 0.019 0.000
6.5556 0.022 0.149 0.020 0.000
6.6667 0.022 0.152 0.021 0.000
6.7778 0.022 0.154 0.023 0.000
6.8889 0.022 0.157 0.024 0.000
7.0000 0.022 0.159 0.025 0.000
7.1111 0.022 0.162 0.026 0.000
7.2222 0.022 0.164 0.027 0.000
7.3333 0.022 0.167 0.028 0.000
7.4444 0.022 0.169 0.029 0.000
7.5556 0.022 0.172 0.030 0.000
7.6667 0.022 0.174 0.031 0.000
7.7778 0.022 0.177 0.032 0.000
7.8889 0.022 0.180 0.032 0.000
8.0000 0.022 0.182 0.033 0.000
8.1111 0.022 0.185 0.034 0.000
8.2222 0.022 0.187 0.035 0.000
8.3333 0.022 0.190 0.035 0.000
8.4444 0.022 0.192 0.036 0.000
8.5556 0.022 0.195 0.037 0.000
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8.6667 0.022 0.197 0.037 0.000
8.7778 0.022 0.200 0.038 0.000
8.8889 0.022 0.202 0.038 0.000
9.0000 0.022 0.205 0.039 0.000
9.1111 0.022 0.207 0.627 0.000
9.2222 0.022 0.210 1.677 0.000
9.3333 0.022 0.212 2.923 0.000
9.4444 0.022 0.215 4.145 0.000
9.5556 0.022 0.218 5.139 0.000
9.6667 0.022 0.220 5.797 0.000
9.7778 0.022 0.223 6.293 0.000
9.8889 0.022 0.225 6.725 0.000
10.000 0.022 0.228 7.131 0.000
10.111 0.022 0.230 7.515 0.000
10.222 0.000 0.000 7.880 0.000
___________________________________________________________________
___________________________________________________________________
ANALYSIS RESULTS
Stream Protection Duration
___________________________________________________________________
Predeveloped Landuse Totals for POC #1
Total Pervious Area:0.66
Total Impervious Area:0
___________________________________________________________________
Mitigated Landuse Totals for POC #1
Total Pervious Area:0.26
Total Impervious Area:0.4
___________________________________________________________________
Flow Frequency Return Periods for Predeveloped. POC #1
Return Period Flow(cfs)
2 year 0.019652
5 year 0.032201
10 year 0.04027
25 year 0.049868
50 year 0.056517
100 year 0.062727
Flow Frequency Return Periods for Mitigated. POC #1
Return Period Flow(cfs)
2 year 0.011939
5 year 0.019584
10 year 0.026204
25 year 0.03667
50 year 0.046218
100 year 0.05747
___________________________________________________________________
Stream Protection Duration
Annual Peaks for Predeveloped and Mitigated. POC #1
Year Predeveloped Mitigated
28Hundred Preliminary Technical Information Report
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1949 0.023 0.008
1950 0.027 0.010
1951 0.043 0.034
1952 0.013 0.008
1953 0.011 0.010
1954 0.017 0.009
1955 0.027 0.009
1956 0.022 0.020
1957 0.017 0.009
1958 0.019 0.010
1959 0.017 0.008
1960 0.030 0.029
1961 0.016 0.011
1962 0.010 0.007
1963 0.014 0.010
1964 0.020 0.010
1965 0.013 0.018
1966 0.013 0.009
1967 0.030 0.010
1968 0.017 0.009
1969 0.017 0.009
1970 0.013 0.010
1971 0.015 0.010
1972 0.033 0.029
1973 0.014 0.017
1974 0.016 0.010
1975 0.022 0.009
1976 0.016 0.009
1977 0.002 0.008
1978 0.013 0.010
1979 0.008 0.007
1980 0.038 0.030
1981 0.012 0.009
1982 0.025 0.020
1983 0.021 0.010
1984 0.013 0.008
1985 0.008 0.008
1986 0.034 0.010
1987 0.030 0.025
1988 0.012 0.008
1989 0.008 0.008
1990 0.071 0.030
1991 0.038 0.026
1992 0.015 0.010
1993 0.015 0.008
1994 0.005 0.007
1995 0.022 0.010
1996 0.050 0.034
1997 0.038 0.033
1998 0.009 0.008
1999 0.042 0.027
2000 0.015 0.010
2001 0.003 0.006
2002 0.017 0.015
2003 0.026 0.009
2004 0.028 0.032
2005 0.021 0.009
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2006 0.023 0.019
2007 0.054 0.061
2008 0.066 0.032
2009 0.031 0.016
___________________________________________________________________
Stream Protection Duration
Ranked Annual Peaks for Predeveloped and Mitigated. POC #1
Rank Predeveloped Mitigated
1 0.0712 0.0613
2 0.0656 0.0342
3 0.0538 0.0335
4 0.0498 0.0327
5 0.0429 0.0324
6 0.0422 0.0322
7 0.0385 0.0301
8 0.0384 0.0300
9 0.0377 0.0292
10 0.0337 0.0285
11 0.0326 0.0271
12 0.0306 0.0256
13 0.0302 0.0250
14 0.0297 0.0205
15 0.0296 0.0198
16 0.0277 0.0194
17 0.0268 0.0176
18 0.0267 0.0168
19 0.0259 0.0162
20 0.0249 0.0153
21 0.0231 0.0105
22 0.0226 0.0105
23 0.0223 0.0104
24 0.0216 0.0103
25 0.0215 0.0102
26 0.0213 0.0101
27 0.0206 0.0101
28 0.0197 0.0100
29 0.0193 0.0100
30 0.0174 0.0098
31 0.0174 0.0097
32 0.0170 0.0097
33 0.0167 0.0097
34 0.0165 0.0096
35 0.0165 0.0096
36 0.0163 0.0095
37 0.0160 0.0094
38 0.0159 0.0093
39 0.0154 0.0093
40 0.0150 0.0093
41 0.0150 0.0092
42 0.0150 0.0092
43 0.0144 0.0091
44 0.0139 0.0090
45 0.0135 0.0090
46 0.0135 0.0089
47 0.0133 0.0087
48 0.0131 0.0084
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49 0.0128 0.0084
50 0.0126 0.0084
51 0.0120 0.0081
52 0.0117 0.0080
53 0.0109 0.0078
54 0.0101 0.0077
55 0.0094 0.0077
56 0.0081 0.0076
57 0.0078 0.0075
58 0.0076 0.0075
59 0.0051 0.0070
60 0.0027 0.0068
61 0.0023 0.0063
___________________________________________________________________
Stream Protection Duration
POC #1
The Facility PASSED
The Facility PASSED.
Flow(cfs) Predev Mit Percentage Pass/Fail
0.0098 17075 14040 82 Pass
0.0103 15505 8671 55 Pass
0.0108 14093 5747 40 Pass
0.0112 12797 5531 43 Pass
0.0117 11569 5366 46 Pass
0.0122 10523 5193 49 Pass
0.0127 9574 5007 52 Pass
0.0131 8763 4836 55 Pass
0.0136 8051 4701 58 Pass
0.0141 7347 4569 62 Pass
0.0145 6733 4378 65 Pass
0.0150 6192 4173 67 Pass
0.0155 5730 3983 69 Pass
0.0160 5313 3826 72 Pass
0.0164 4926 3632 73 Pass
0.0169 4569 3382 74 Pass
0.0174 4235 3200 75 Pass
0.0178 3951 3061 77 Pass
0.0183 3645 2909 79 Pass
0.0188 3390 2719 80 Pass
0.0193 3133 2537 80 Pass
0.0197 2915 2351 80 Pass
0.0202 2706 2205 81 Pass
0.0207 2490 2079 83 Pass
0.0211 2314 1953 84 Pass
0.0216 2136 1849 86 Pass
0.0221 1973 1768 89 Pass
0.0226 1827 1704 93 Pass
0.0230 1702 1636 96 Pass
0.0235 1577 1573 99 Pass
0.0240 1443 1493 103 Pass
0.0244 1325 1411 106 Pass
0.0249 1233 1320 107 Pass
0.0254 1148 1219 106 Pass
0.0259 1083 1140 105 Pass
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0.0263 1020 1070 104 Pass
0.0268 947 1012 106 Pass
0.0273 887 930 104 Pass
0.0277 825 872 105 Pass
0.0282 761 804 105 Pass
0.0287 725 722 99 Pass
0.0292 674 636 94 Pass
0.0296 623 561 90 Pass
0.0301 589 463 78 Pass
0.0306 549 424 77 Pass
0.0310 506 362 71 Pass
0.0315 469 308 65 Pass
0.0320 427 249 58 Pass
0.0325 388 196 50 Pass
0.0329 356 172 48 Pass
0.0334 328 151 46 Pass
0.0339 298 132 44 Pass
0.0344 270 116 42 Pass
0.0348 241 112 46 Pass
0.0353 218 107 49 Pass
0.0358 198 102 51 Pass
0.0362 174 87 50 Pass
0.0367 152 77 50 Pass
0.0372 130 64 49 Pass
0.0377 119 55 46 Pass
0.0381 104 47 45 Pass
0.0386 95 38 40 Pass
0.0391 83 32 38 Pass
0.0395 74 12 16 Pass
0.0400 69 12 17 Pass
0.0405 61 12 19 Pass
0.0410 53 12 22 Pass
0.0414 46 12 26 Pass
0.0419 39 11 28 Pass
0.0424 29 11 37 Pass
0.0428 25 10 40 Pass
0.0433 22 8 36 Pass
0.0438 20 8 40 Pass
0.0443 17 8 47 Pass
0.0447 14 8 57 Pass
0.0452 12 6 50 Pass
0.0457 8 6 75 Pass
0.0461 7 6 85 Pass
0.0466 7 6 85 Pass
0.0471 7 6 85 Pass
0.0476 6 6 100 Pass
0.0480 6 6 100 Pass
0.0485 6 5 83 Pass
0.0490 6 5 83 Pass
0.0494 6 5 83 Pass
0.0499 5 5 100 Pass
0.0504 5 5 100 Pass
0.0509 5 4 80 Pass
0.0513 5 4 80 Pass
0.0518 5 4 80 Pass
0.0523 5 3 60 Pass
0.0527 5 3 60 Pass
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0.0532 4 3 75 Pass
0.0537 4 3 75 Pass
0.0542 3 3 100 Pass
0.0546 3 2 66 Pass
0.0551 3 2 66 Pass
0.0556 3 2 66 Pass
0.0560 3 1 33 Pass
0.0565 3 1 33 Pass
_____________________________________________________
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 18
Existing Conditions Map
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Developed Conditions Map
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 20
V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Conveyance calculations will be provided as part of the final engineering documents.
VI. SPECIAL REPORTS AND STUDIES
“Infiltration Evaluation Proposed Harrington Glade Townhomes 2800 Northeast 12th Street
Renton, Washington”, dated August 1, 2014, and prepared by Earth Solutions NW . See Appendix
A.
VII. OTHER PERMITS
N/A
VIII. CSWPPP ANALYSIS AND DESIGN
This Stormwater Pollution Prevention Plan (SWPPP)/TESC will be prepared as part permit requirements for
this project in City of SeaTac, Washington during final engineering.
IX. BOND QUANTITIES, FACILITY SUMMARIES, & DECLARATION OF COVENANT
The documents will be prepared and submitted as part of the final engineering documents.
X. OPERATIONS AND MAINTENANCE MANUAL
Operation and maintenance of the site and all proposed stormwater facilities on this project will be
required after the construction completion and throughout the life of this development. Details
will be provided during final engineering.
28Hundred Preliminary Technical Information Report
April 10, 2018 Page 21
Appendix A Infiltration Evaluation
Infiltration Evaluation Proposed Harrington Glade Townhomes 2800 Northeast 12th Street Renton,
Washington