HomeMy WebLinkAboutB930106 STORM DRAINAGE CALCULATIONS
FOR
TUM-A-LUM LUMBER
RENTON, WASHINGTON
KING COUNTY, WASHINGTON'
BALD FILE NO. S90P0090
OUR JOB NO. 4751
PREPARED BY:
BARGHAUSEN CONSULTING ENGINEERS, INC.
C"of MWON
18215 72nd Avenue South E C E I V E D
Kent, Washington 98032 DEC 6 1993
(206) 251-6222 BUILDING DIVISION
of w:.&ly,Mc"�
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DECEMBER 6, 1993 0 239-5
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TABLE OF CONTENTS
I. INTRODUCTION/GENERAL INFORMATION:
A. General Information
1. TIR Worksheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Site Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
II. OFF-SITE ANALYSIS:
A. Upstream Drainage Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B. Downstream Drainage Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
III. STORM DRAINAGE ANALYSIS AND DESIGN
A. Existing Site Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B. Developed Site Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C. Hydraulic Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV. CONVEYANCE SYSTEM DESIGN AND ANALYSIS
V. BASIN AND COMMUNITY PLAN AREAS
VI. MAINTENANCE AND OPERATION MANUAL
4751.005
I. PROJECT OVERVIEW
INTRODUCTION AND GENERAL DRAINAGE INFORMATION:
The proposed project is to include an expansion of approximate 8,500 square feet to the existing
Tum-a-Lum Lumber Company project site located along the existing ARCO AM/PM Mini-Market project-
at the northwest quadrant of Duvall Avenue N.E. and N.E. Sunset Boulevard. The proposed site is on an
existing graded area which has field grasses and some trees located along the north boundary of the
property. The proposal is to produce a plan for the storage of Tum-a-Lum Lumber Company's lumber and
equipment and have two accesses as shown on the attached drainage plan. There will be an access from
end to end, which will incorporate approximately 3,000± square feet of driveable surface area that will
be gravel. The remaining site, which will be storage area, will also be gravel surface material. The
northern approximately 15 feet will be a landscape buffer that will be left as is. Since this site incorporates
less than 5,000 square feet of driveable surface area, biofiltration facilities are not required. Detention
facilities will not be required since the overall increase in runoff is less than 0.5 cfs for the 100-year storm
event. There will, however, be one catch basin installed within the driveable area that will be connected
directly to the Duvall Avenue N.E. drainage system as shown on the attached drainage plan.
Page 1 of 1 4751.002 [HPG/sm]
Page 1 of 2
King County Building and Land Development Division
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
PART I PROJECT OWNER AND PART 2 PROJECT LOCATION
PROJECT ENGINEER ANDDESCRIPTION
Project Owner Project Name
Location
Address 4��c Fnr. � �` r t_VL
Phone ���, - �-- 11 1`�
Township '
Range
Project EnginaAr H P,11 P. C,f?�.I g
Section
Company tic (l luSi✓ki ;�-^� �1,. �L Project Size
Address Phone l��t` �`�1 Upstream Drainage Basin Size — - AC
7 i
PART 3 TYPE OF PERMIT APPLICATION PART 4 OTHER PERMITS
Q Subdivision ED DOF/G HPA 0 Shoreline Management
F-1 Short Subdivision F1 COE 404 ED Rockery
ED Grading 0 DOE Dam Safety 0 Structural Vaults
M Commercial 0 FEMA Floodplain E:1 Other
F--1 Other COE Wetlands E-1 HPA
PART •MMUNITY AND DRAINAGE BASIN
Community �) -
n
Drainage BasinPART 6 SITE
CHARACTERISTICS
River 0 Floodplain
Stream Wetlands
0 Critical Stream Reach Seeps/Springs
0 Depressions/Swales High Groundwater Table
ED Lake Groundwater Recharge
E] Steep Slopes ED CAher
ED Lakeside/Erosion Hazard
PART 7 SOILS
Soil Type Slopes Erosion Potential Erosive Velocities
LJ Additional Sheets Attatched
Page 2 of 2 S
King County Building and Land Development Division
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
DEVELOPMENTPARTS •
REFERENCE LIMITATION/SITE CONSTRAINT
Q Ch.4-Downstream Analysis
0
0
a
0
C3
Q Additional Sheets Attatched
REQUIREMENTSPART 9 ESC
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION FOLLOWING CONSTRUCTION
Q Sedimentation Facilities Q Stabilize Exposed Surface
Q Stabilized Construction Entrance Q Remove and Restore Temporary ESC Facilities
Q Perimeter Runoff Control 0 Clean and Remove All Silt and Debris
0 Clearing and Grading Restrictions 0 Ensure Operation of Permanent Facilities
Q Cover Practices 0 Flag Limits of NGPES
Q Construction Sequence Other
Q Other
PART 10 SURFACE WATER SYSTEM
0 Grass Lined Channel O Tank 0 Infiltration Method of Analysis
( Pipe System Q Vault Q Depression LU,i-It
Q Open Channel Q Energy Dissapator Q Flow Dispersal Compensation/Mitigation
Cl Dry Pond Wetland F� Waiver of Eliminated Site Storage
ED Wet Pond E:] Stream 0 Regional Detention
Brief Description of System Operation
V l ;i F [V't"L , �rLv% <:�i��t+c: L vL
Facility Related Site Limitations Q Additional Sheets Attatched
Reference Facility Limitation
PART 12 EASEMENTS/TRACTS
PART11 STRUCTURAL ANALYSIS
(May require special structural review) [-1 Drainage Easement
Q Cast in Place Vault F--� Other ( Access Easement
Q Retaining Wall Q Native Growth Protection Easement
Q Rockery>4'High ! Q Tract
[� Structural on Steep Slope
Q Other
PART14 SIGNATURE OF - . •
I or a civil engineer under my supervision have visited the site. Actual
site conditions as observed were incorporated into this worksheet and the
attatchments. To the best of my knowledge the information provided !
here is accurate.
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12/ 5/93 Barghausen Engineers page 3
TUM-A-LUM LUMBER STORAGE AREA ADDITION
BY REH
12-05-93
HYDROGRAPH SUMMARY
PEAK TIME VOLUME
HYD RUNOFF OF OF Contrib
NUM RATE PEAK HYDRO Area
cfs min. cf-AcFt Acres
1 0. 021 490 748 cf 0. 41 C- X. Z Ye-z y Ht2-
2 0. 026 480 710 cf 0. 41 oEu. Z_vZ-7-1-t H2.
3 0. 628 480 10620 cf 0. 41 cx• /e-,LYk
4 0.771 480 10484 cf 0. 41 DF-v,
i`
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b. LA 3 c-Vs i,u �� c%•S �-ls
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;
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12/ 5/93 Barghausen Engineers page 1
TUM-A-LUM LUMBER STORAGE AREA ADDITION
BY REH
12-05-93
BASIN SUMMARY
BASIN ID: lA NAME: STORAGE AREA EX 2YR-24HR
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 0.41 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 2. 10 inches AREA. . : 0.41 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 77. 00
TIME OF CONC. . . . . : 21. 05 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres
CN. . . . . 76. 00
TcReach - Sheet L: 220. 00 ns: 0. 1300 p2yr: 2 . 10 s: 0. 0182
PEAK RATE: 0. 02 cfs VOL: 0. 02 Ac-ft TIME: 490 min
BASIN ID: 1B NAME: DEV. 2YR-24HR STORM EVENT
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 0.41 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 2 . 10 inches AREA. . : 0. 12 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 77 . 00
TIME OF CONC. . . . . : 7 . 30 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 0. 29 Acres
CN. . . . . 76. 00
PEAK RATE: 0. 03 cfs VOL: 0. 02 Ac-ft TIME: 480 min
J'
BASIN ID: 2A NAME: EX. 100YR-. _ STORM EVENT
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 0. 41 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 10. 00 inches AREA. . : 0. 41 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 77 . 00
TIME OF CONC. . . . . : 21. 05 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres
CN. . . . . 76. 00
TcReach - Sheet L: 220. 00 ns: 0. 1300 p2yr: 2 . 10 s: 0. 0182
PEAK RATE: 0. 63 cfs VOL: 0. 24 Ac-ft TIME: 480 min
12/ 5/93 Barghausen Engineers page 2
TUM-A-LUM LUMBER STORAGE AREA ADDITION
BY REH
12-05-93
BASIN SUMMARY
BASIN ID: 2B NAME: DEV 100YR- STORM
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 0.41 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 10. 00 inches AREA. . : 0. 12 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 77 . 00
TIME OF CONC. . . . . : 7 . 30 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 0. 29 Acres
CN. . . . . 76. 00
PEAK RATE: 0.77 cfs VOL: 0.24 Ac-ft TIME: 480 min
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U. S. DEPARTMENT Of AGRICULTURE
SOIL CONSERVATION SERVICE KING COUNTY AREA, Wl�
SOIL LEGEND
The first capital levier is the initial one of the soil name. A second coartcl kt+er,
A,B,C.D,E,a F. indicates the class of slope. Symbols without o slope letter
are those of nearly level sails.
SYMBOL NAME
A98 Aldetv.00d gravelly sandy loam,0 to 6 percent slopes ,a
AgC Alderwood gravelly sandy loam,6 to 15 percent slopes
AgD Aldervrood gravelly sandy loom, 15 to 30 percent slopes
AkF Alderwood and Kitsop soils,very steep
A.8 Arents,Alrierwood material,0 to 6 percent slopes• 1•c
AmC Aliens,Ak:,rwood material,6 to 15 percent slopes
An Arents,Everett material• 1'
BeC -Beausite gravelly sandy loam,6 to 15 percent slopes
SeD Beaus ite gravelly sandy loom, 15 to 30 percent slopes
¢eF Brxroite grovel!; Ica=,"3:o?S
Bh Bellioghom silt loam ......
Br Briscat silt loom
Bu Buckley silt loom i
Cb Coastal Beaches -
Ea Eorlmont silt loom
Ed .Edg—ick fine sandy loom
&S Everett groveily sandy loom,0 to 5 percent slopes
111111111110 Evc Everett gravelly sotndy loam,5 to 15 percent slopes
EvD Everett gravelly sandy loam, 15 to 30 percent slopes x<•..
E—C Everett-Aklerwood gravelly sandy looms,6 to 15 percent slaves
InA Indianola k»my fine send,0 to 4 percent slopes
InC kdionola loamy fine sord,4 to 15 percent slopes - -
InD Indianola loomy fine send, 15 to 30 percent slopes
KPB Kitsop silt loom,2 to S percent slopes I;.-•k
KpC Kitsop silt loom,6 to 15 percent slopes
t Kp0 Kitsop silt loom, 15 to 30 percent slopes
r KsC Klaus gravelly loamy sold,6 to 15 percent slopes
4t'7 Ma Mixed alluvial land .._..-.
Nee Nei it—very grave l ly loamy solid,2 to 15 percent slopes --
Ng Newberg silt loom
Nk Nooksack silt loom
No Norma sandy loom _
Or Orcas pea,
Os O-:dia sill loom
OvC Ovoll gravelly loam,0 to 15 percent s lopes
OvD Ovals gravelly loom, 15 to 25 percent slopes
OvF Ovoll gravelly loom,40 to 75 percent slopes
PC Pilchuck loamy fine sand
Pk P:Ichuck fine sandy.loom
Pu Puget silty cloy loom
Py Puyallup fine sandy loom
Roc Rogrvor fine sandy loom,6 to 15 percent slopes
Rap Roans fine sandy loom, 15 to 25 percent slopes
RdC Raanar-Indianola association,sloping
RdE Rognwr-Ind:anolo ossociation,moderately steed
Re Renton silt loom
Rh P,vcnwash
So Solal silt I«m
SI. Sommomish sd, loom
Sk Scavi le—„ '
Sm Shok.,m
Sn S:silt loom
So Snohomish s•It loom
S Snohom sh s h loom• thick surface von ions
Su Svl+on sal+ IRm
T. Tuk-1.mac
U, Urban lone
11'0 \':cod•nvrllr-.7• ICam
• llv canapes•••an of -se. s ro n..vC vo,whir••ho.•that,.1 •... ..+ •.
•n nl.r•o•�c.tv. ..1'c'. . r.Y.+r a;ll.-..M..II. .�.r71,r...n.n + .r 1.•
C:t.•c rd.•sr Cr rh• _.
KING COUNTY, WASHINGTON, SU.RFACE WATER DESIGN MANUAL
FIGURE 3.5.2A HYDROLOGIC SOIL GROUP OF THE SOILS INKING COUNTY
HYDROLOGIC HYDROLOGIC
SOIL GROUP GROUP* SOIL GROUP GROUP`
Alderwood C Orcas Peat - 0
Arents, Alderwood Material C Or'idia D
Arents, Everett Material B Oval[ C
Beausite C Pilchuck C
Bellingham D Puget 0
Briscot D Puyallup B
Buckley D Ragnar B
Coastal Beaches Variable Renton D
Eadmont Sal Loam Riverwash Variable
Edgewick Salal C
Everett A Sammamish D
Indianola A Seattle D
Kitsap Shacar 0
Klaus C Si Sat C
Moved Alluvial Land Variable Snohomish D
Neaton A Sultan C
Newberg B Tukwila D
Nooksack C Urban Variable
Normal Sandy loam D Woodinville 0
HYDROLOGIC SOIL GROUP CLASSIFICATIONS
A- (Low runoff potential). Soils having high Infiltration rates,even when thoroughly wetted,and consisting
chiefly of deep,well-to-excessively drained sands or gravels. These sods have a high rate of water
transmission.
B. (Moderately low runoff potential). Soils having moderate infiltration rates when thoroughly wetted, and
consisting chiefly of moderately fine to moderately coarse textures. These soils have a moderate rate of
water transmission.
C. (Moderately high runoff potential). Soils having slow infiltration rates when thoroughly wetted, and
consisting chiefly of soils with a layer that impedes downward movement of water, a soils with moderately
fine to fine textures. These soils have a slow rate of water transmission.
D. (High runoff potential). Soils having very slow infiltration rates when thoroughly wetted and consisting
chiefly of day soils with a high swelling potential, soils with a permanent high water table, soils with a
hardpan or day layer at or near the surface,and shallow soils over nearly impervious material. These soils
have a very slow rate of water transmission.
From SCS.TR-55, Second Edition, June 1986. Exhibit A-1. Revisions made from SCS. Soil Interpretation
Record. Form V5, September 1988.
3.52-2 1
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
TABLE 3.5.2B SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS
SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982)
Runoff curve numbers for selected agricultural, suburban and urban land use for Type to
rainfall disttibution, 24-hour storm duration.
CURVE NUMBERS BX
HYDROLOGIC SOIL GROUP
LAND USE DESCRIPTION A B C D
Cultivated land(i): winter'condition 86 91 94 95
Mountain open areas: low growing brush and grasslands 74 82 89 92
Meadow or pasture: 65 78 85 89
Wood or forest land: undisturbed 42 64 76 81
Wood or forest land: young second growth or txush 55 72 81 86
Orchard: with cover crop 81 88 92 94
Open spaces,lawns, parks, golf courses,cemeteries.
landscaping.
good condition: grass cover on 75%
or more of the area 68 80 S& 90
fair condition: grass.cover on 50%
to 75%of the area 77 85 90 92
Gravel roads and parking lots 6 85 89 -91
Dirt roads and parking lots 2 82 87 89 .
Impervious stirfaces, pavement, roofs, etc. 98 98 98 98
Open water bodies: takes,wetlands, ponds, etc. 100 100 100 100
Single Family Residential (2)
Dwelling Unit/Gross Acre % Impervious (3)
1.0 DU/GA 15 Separate curve number
1.5 DU/GA 20 shall be selected
2"0 DU/GA 25 for pervious and
2.5 DU/GA 30 impervious portion
3.0 DU/GA 34 of the site or basin
3.5 DU/GA 38
4.0 DU/GA 42
4.5 DU/GA 46
5.0 DU/GA 48
5.5 DU/GA s0
6.0 DU/GA 52
6.5 DU/GA 54
7.0 DU/GA 56
Planned unit developments. % impervious
condominiums, apartments• must be computed
commercial business and
industrial areas.
(1) For a more detailed description of agricultural land use curve numbers refer to National Engineering
Handbook, Section 4, Hydrology, Chapter 9• August 1972.
(2) Assumes roof and driveway runoff is directed into street/storm system.
(3) The remaining pervious areas (lawn) are considered to be in good condition for these curve numbers.
3"5.2-3
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"I. MAINTENANCE AND OPERATION MANUAL
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
MAINTENANCE REQUIREMENTS FOR
PRIVATELY MAINTAINED DRAINAGE FACILITIES
NO. 1 - PONDS
Maintenance Conditions When Maintenance Results Expected
Component Defect Is Needed When Maintenance is Performed
General Trash &Debris Any trash and debris which exceed 1 Trash and debris cleared from site.
cubic foot per 1000 square feet (this is
about equal to the amount of trash it
would take to fill up one standard size
office garbage can). in general,there
should be no visual evidence of dumping.
Poisonous Any poisonous vegetation which may No danger of poisonous vegetation where
Vegetation constitute a hazard to County personnel County personnel or the public might
or the public. Examples of poisonous normally be. (Coordination with
vegetation include: tansy ragwort, poison Seattle/King County Health Department)
oak, stinging nettles,devils club.
Pollution Oil,gasoline,or other contaminants of No contaminants present other than a
one gallon or more or any amount found surface film. (Coordination with
that could: 1)cause damage to plant, Seattle/King County Health Department)
animal,or marine life; 2) constitute a fire
hazard;or 3)be flushed downstream
during rain storms.
Unmowed Grass/ if facility is located in private residential When mowing is needed,grass/ground
Ground Cover area,mowing is needed when grass cover should be mowed to 2 inches in
exceeds 18 inches in height. In other height.
areas,the general policy is to make the
pond site match adjacent ground cover
and terrain as long as there is no
interference with the function of the
facility-
Rodent Holes Any evidence of rodent holes if facility is Rodents destroyed and dam or berm
acting as a dam or berm,or any evidence repaired. (Coordination with Seattle/
of water piping through dam or berm via King County Health Department)
rodent holes.
Insects When insects such as wasps and hornets Insects destroyed or removed from site.
interfere with maintenance activities.
Tree Growth Tree growth does not allow maintenance Trees do not hinder maintenance
access or interferes with maintenance activities. Selectively cultivate trees such
activity (i.e., slope mowing, silt removal, as alders for firewood.
vactoring or equipment movements). if
trees are not interfering with access, leave
trees alone.
Side Slopes of Erosion Eroded damage over 2 inches deep Slopes should be stabilized by using
Pond where cause of damage is still present or appropriate erosion control measure(s):
where there is potential for continued e.g., rock reinforcement, planting of
erosion. grass, compaction.
Storage Area Sediment Accumulated sediment that exceeds 10% Sediment cleaned out to designed pond
of the designed pond depth. shape and depth; pond reseeded if
necessary to control erosion.
Pond Dikes Settlements Any part of dike which has settled 4 Dike should be built back to the design
inches lower than the design elevation. elevation.
Emergency Rock Missing Only one layer of rock exists above native Replace rocks to design standards.
Overflow/Spillway soil in area five square feet or larger, or
any exposure of native soil.
A-1 I/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
10. 2 - INFILTRATION
Maintenance Conditions When Maintenance When Expected
ce is Performed
Component Defect Is Needed
General Trash &Debris See'Ponds"Standard No. 1 See'Ponds Standard No. 1
Poisonous See'Ponds'Standard No. 1 See'Ponds Standard No. 1
Vegetation
Pollution See'Ponds'Standard No. 1 See"Ponds Standard No. 1
Unmowed Grass/ See"Ponds" Standard No. 1 See'Ponds Standard No. 1
Ground Cover
Rodent Holes See"Ponds'Standard No. 1 See"Ponds Standard No. 1
Insects See'Ponds"Standard No. 1 See'Ponds Standard No. 1
Storage Area Sediment A percolation test pit or test of facility Sediment is removed and/or facility is
indicates facility is only working at 90%of cleaned so that infiltration system works
its designed capabilities. according to design.
Street Cover Sheet cover is visible and has more than Sheat cover repaired or replaced.
(if Applicable) three 1/44nch holes in it.
Sump Filled With Any sediment and debris filling vault to Gean out sump to design depth.
Sediment and 10%of depth from sump bottom to
Debris (H bottom of outlet pipe or obstructing flow
Applicable) into the connector pipe.
Titer Bags Filled with Sediment and debris fill bag more than Replace filter bag or redesign system.
Sediment and 1/2 full.
Debris
.lock Filters Sediment and By visual inspection little or no water Replace gravel in rock filter.
Debris flows through filter during heavy rain
storms.
A-2 1/90
i
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 3 - CLOSED DETENTION SYSTEMS (PIPES/TANKS)
Maintenance Conditions When Maintenance Results Expected
Component Defect Is Needed When Maintenance Is Performed
Storage Area Plugged Air Vents One-half of the cross section of a vent is Vents free of debris and sediment.
blocked at any point with debris and
sediment.
Debris and Accumulated sediment depth exceeds Al sediment and debris removed from
Sediment 10%of the diameter of the storage area storage area.
for 1/2 length of storage vault or any
point depth exceeds 15%of diameter.
Example: 72-inch storage tank would
require cleaning when sediment reaches
depth of 7 inches for more than 1/2
length of tank.
Joints Between Any crack allowing material to be All joints between tank/pipe sections are
Tank/Pipe Section transported into facility. sealed.
Tank/Pipe Bent Any part of tank/pipe is bent out of shape Tank/pipe repaired or replaced to design.
Out of Shape more than 10%of its design shape.
Manhole Cover not in Place Cover is missing or only partially in place. Manhole is closed.
Any open manhole requires maintenance.
Locking Mechanism cannot be opened by one Mechanism opens with proper tools.
Mechanism Not maintenance person with proper tools.
Working Bolts into frame have less than 1/2 inch
of thread(may not apply to self-locking
lids).
Cover Difficult to One maintenance person cannot remove Cover can be removed and reinstalled by
Remove lid after applying 80 pounds of lift. Intent one maintenance person.
is to keep cover from sealing off access
to maintenance.
Ladder Rungs King County Safety Office and/or Ladder meets design standards and
Unsafe maintenance person judges that ladder is allows maintenance persons safe access.
unsafe due to missing rungs,
misalignment, rust,or cracks.
Catch Basins See "Catch Basins` Standard No. 5 See "Catch Basins" Standard No. 5
A-3 I/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
10. 4 - CONTROL STRUCTURE/FLOW RESTRICTOR
Maintenance Conditions When Maintenance Results Expected
Component Defect Is Needed When Maintenance Is Performed
General Trash and Debris Distance between debris build-up and All trash and debris removed.
(Includes bottom of orifice plate is less than 1-1/2
Sediment) feet.
Structural Damage Structure is not securely attached to Structure securely attached to wall and
manhole wall and outlet pipe structure outlet pipe.
should support at least 1,000 pounds of
up or down pressure.
Structure is not in upright position (allow Structure in correct position.
up to 1o%from plumb).
Connections to outlet pipe are not Connections to outlet pipe are watertight;
watertight and show signs of rust. structure repaired or replaced and works
as designed.
Any holes—other than designed holes— Structure has no holes other than
in the structure. designed holes.
Cieanout Gate Damaged or Cleanout gate is not watertight or is Gate is watertight and works as designed.
Missing missing.
Gate cannot be moved up and down by Gate moves up and down easily and is
one maintenance person. watertight.
Chain leading to gate is missing or Chain is in place and works as designed.
damaged.
Gate is rusted over 50%of its surface Gate is repaired or replaced to meet
area design standards.
Orifice Plate Damaged or Control device is not working properly Plate is in place and works as designed.
Missing due to missing,out of place,or bent
orifice plate.
Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions and works
blocking the plate. as designed.
Overflow Pipe Obstructions Any trash or debris blocking (or having Pipe is free of all obstructions and works
the potential of blocking) the overflow as designed.
pipe.
Manhole See "Closed Detention Systems" Standard See "Closed Detention Systems" Standard
No. 3. No. 3.
Catch Basin See "Catch Basins"Standard No. 5. See "Catch Basins"Standard No. 5.
I/90
A-4 —
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 5 - CATCH BASINS
Maintenance Conditions When Maintenance Results Expected
Component Defect Is Needed When Maintenance Is Performed
General Trash &Debris Trash or debris of more than 1/2 cubic No trash or debris located immediately in
(Includes foot which is located immediately in front front of catch basin opening.
Sediment) of the catch basin opening or is blocking
capacity of basin by more than 10%.
Trash or debris (in the.basin)that No trash or debris in the catch basin.
exceeds 1/3 the depth from the bottom
of basin to invert of the lowest pipe into
or out of the basin.
Trash or debris in any inlet or outlet pipe Inlet and outlet pipes free of trash or
blocking mote than 1/3 of its height. debris.
Dead animals or vegetation that could No dead animals or vegetation present
generate odors that would cause within the catch basin.
complaints or dangerous gases (e.g.,
methane).
Deposits of garbage exceeding 1 cubic No condition present which would attract
foot in volume. or support the breeding of insects or
rodents.
Structural Damage Corner of frame extends more than 3/4 Frame is even with curb.
to Frame and/or inch past curb face into the street (f
Top Slab applicable).
Top slab has holes larger than 2 square Top slab is free of holes and cracks.
inches or cracks wider than 1/4 inch
(intent is to make sure all material is
running into the basin).
Frame not sitting flush on top slab, i.e., Frame is sitting flush on top slab.
separation of more than 3/4 inch of the
frame from the top slab.
Cracks in Basin Cracks wider than 1/2 inch and longer Basin replaced or repaired to design
Walls/Bottom than 3 feet,any evidence of soil particles standards.
entering catch basin through cracks, or
maintenance person judges that structure
is unsound.
Cracks wider than 1/2 inch and longer No cracks more than 1/4 inch wide at the
than 1 foot at the joint of any inlet/outlet joint of inlet/outlet pipe.
pipe or any evidence of soil particles
entering catch basin through cracks.
Settlement/ Basin has settled more than 1 inch or has Basin replaced or repaired to design
Misalignment rotated more than 2 inches out of standards.
alignment.
Fire Hazard Presence of chemicals such as natural No flammable chemicals present.
gas,oil,and gasoline.
Vegetation Vegetation growing across and blocking No vegetation blocking opening to basin.
more than 10%of the basin opening.
Vegetation growing in inlet/outlet pipe No vegetation or root growth present.
joints that is more than six inches tall and
less than six inches apart.
Pollution Nonflammable chemicals of more than No pollution present other than surface
1/2 cubic foot per three feet of basin film.
length.
A-S
1/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
10. 5 - CATCH BASINS (Continued)
Maintenance Conditions When Maintenance Results Expected
Component Defect Is Needed When Maintenance Is Performed
Catch Basin Cover Cover Not in Place Cover is missing or only partially in place. Catch basin cover is closed.
Any open catch basin requires
maintenance.
Locking Mechanism cannot be opened by one Mechanism opens with proper tools.
Mechanism Not maintenance person with proper tools.
Working Bolts into frame have less than 1/2 inch
of thread.
Cover Difficult'o One maintenance person cannot remove Cover can be removed by one
Remove lid after applying 80 lbs.of lift; intent is maintenance person.
keep cover from sealing off access to
maintenance.
Ladder ladder Rungs Ladder is unsafe due to missing rungs, Ladder meets design standards and
Unsafe misalignment, rust,cracks,or sharp allows maintenance person safe access.
edges.
Metal Grates Grate with opening wider than 7/8 inch. G,dte openings meet design standards.
(f applicable)
Trash and Debris Trash and debris that is blocking more Grate free of trash and debris.
than 20%of grate surface.
Damaged or Grate missing or broken member(s) of Grate is in place and meets design
Missing the grate. standards.
A-6 1/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 6 - DEBRIS BARRIERS (e.g. Trash Racks)
Maintenance Conditions When Maintenance Resutts Expected
Component Defect Is Needed When Maintenance Is Performed
General Trash and Debris Trash or debris that is plugging more Barrier clear to receive capacity flow.
than 20%of the openings in the barrier.
Metal Damaged/Missing Bars are bent out of shape more than 3 Bars in place with no bends more than
Bars inches. 3/4 inch.
Bars are missing or entire barrier is Bars in place according to design.
missing.
Bars are loose and rust is causing 50% Repair or replace barrier to design
deterioration to any part of barrier. standards.
-1/90
A-7
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 7 - ENERGY DISSIPATORS
Maintenance Conditions When Maintenance Results Expected
Component Defect Is Needed When Maintenance Is Performed
External:
Rock Pad Missing or Moved Only one layer of rock exists above native Replace rocks to design standard.
Rock soil in area five square feet or larger,or
any exposure of native soil.
Dispersion Trench Pipe Plugged with Accumulated sediment that exceeds 20% Pipe cleaned/flushed so that it matches
Sediment of the design depth. design.
Not Discharging Visual evidence of water discharging at Trench must be redesigned or rebuilt to
Water Properly concentrated points along trench (normal standard.
condition is a'sheet flow"of water along
trench). Intent is to prevent erosion
damage.
Perforations Over 1/2 of perforations in pipe are Clean or replace perforated pipe.
Plugged plugged with debris and sediment.
Water F.jws Out Maintenance person observes water Facility must be rebuilt or redesigned to
Top oT'Distributor' flowing out during any storm less than standards.
Catch Basin the design storm or It is causing or
appears likely to cause damage.
Receiving Area Water in receiving area is causing or has No danger of landslides.
Over-Saturated potential of causing landslide problems.
Internal:
Manhole/Chamber Worn or Damaged Structure dissipating flow deteriorates to Replace structure to design standards.
Posts, Baffles, 1/2 or original size or any concentrated
Sides of Chamber worn spot exceeding one square foot
which would make structure unsound.
Other Defects See 'Catch Basins'Standard No.5 See 'Catch Basins"Standard No. 5
A-8
I/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 8 - FENCING
Maintenance Conditions When Maintenance Results Expected
Component Defect Is Needed When Maintenance Is Performed
General Missing or Broken My defect in the fence that permits easy Parts in place to provide adequate
Parts entry to a facility. security.
Parts broken or missing. Broken or missing parts replaced.
Erosion Erosion more than 4 inches high and 12- No opening under the fence that exceeds
18 inches wide permitting an opening 4 inches in height.
under a fence.
Wire Fences DamagecA Parts Posts out of plumb more than 6 inches. Posts plumb to within 1-1/2 inches.
Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch.
Any part of fence (including posts,top Fence is aligned and meets design
rails,and fabric)more than 1 foot out of standards.
design alignment.
Missing or loose tension wire. Tension wire in place and holding fabric.
Missing or loose barbed wire that is Barbed wire in place with less than 3/4-
sagging more than 2-1/2 inches between inch sag between posts.
posts.
Extension arm missing, broken,or bent Extension arm in place with no bends
out of shape more than 1-1/2 inches. larger than 3/4 inch.
Deteriorated Paint Part or parts that have a rusting or scaling Structurally adequate posts or parts with
or Protective condition that has affected structural a uniform protective coating.
Coating adequacy.
Openings in Fabric Openings in fabric are such that an 8- No openings in fabric.
inch-diameter ball could fit through.
I
A-9 100
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
GATES
Maintenance Conditions When Maintenance Results Expected
ance Is Performed
Component Defect Is Needed When
General Damaged or Missing gate or locking devices. Gates and locking devices in place.
Missing Members
Broken or missing hinges such that gate Hinges intact and tubed. Gate is working
cannot be easily opened and closed by a freely.
maintenance person.
Gate is out of plumb more than 6 inches Gate is aligned and vertical.
and more than 1 foot out of design
alignment.
Missing stretcher bar,stretcher bands, Stretcher bar,bands,and ties in place.
and ties.
Openings In Fabric See "Fencing"Standard No. 8 See"Fencing' Standard No.8
1/90
A-10
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 10 - CONVEYANCE SYSTEMS (Pipes & Ditches)
Maintenance Conditions When Maintenance Results Expected
Component Defect is Needed When Maintenance is Performed
Pipes Sediment&Debris Accumulated sediment that exceeds 20% Pipe cleaned of all sediment and debris.
of the diameter of the pipe.
Vegetation Vegetation that reduces free movement of All vegetation removed so water flows
water through pipes. freely through pipes.
Damaged Protective coating is damaged,rust is Pipe repaired or replaced.
causing more than 50%deterioration to
any part of pipe.
Any dent that decreases the cross section Pipe repaired or replaced.
area of pipe by more than 20%.
Open Ditches Trash &Debris Trash and debris exceeds 1 cubic foot Trash and debris cleared from ditches.
per 1,000 square feet of ditch and slopes.
Sediment Accumulated sediment that exceeds 20% Ditch cleaned/flushed of all sediment and
of the design depth. debris so that it matches design.
Vegetation Vegetation that reduces free movement of Water flows freely through ditches.
water through ditches.
Erosion Damage to See"Ponds'Standard No. 1 See "Ponds"Standard No. 1
'Slopes
Rock Lining Out of Maintenance person can see native soil Replace rocks to design standard.
Place or Missing (If beneath the rock lining.
Applicable)
Catch Basins See'Catch Basins" Standard No. 5 See "Catch Basins" Standard No. 5
Debris Barriers See"Debris Barriers' Standard No. 6 See 'Debris Barriers"Standard No.6
(e.g.,Trash Rack)
A-11 1/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 11 - GROUNDS (Landscaping)
Maintenance Conditions When Maintenance Results Expected
Component Defect is Needed When Maintenance Is Performed
General Weeds Weeds growing in more than 20% of the Weeds present in less than 5%of the
(Nonpoisonous) landscaped area (trees and shrubs only). landscaped area.
Safety Hazard Any presence of poison Ivy or other No poisonous vegetation present in a
poisonous vegetation. landscaped area.
Trash or Litter Paper,can, bottles,totalling more than 1 Area clear of litter.
cubic foot within a landscaped area (trees
and shrubs only)of 1,000 square feet.
Trees and Shrubs Damage lambs or parts of trees or shrubs that are Trees and shrubs with less than 5%of the
split or broken which affect more than total foliage with split or broken limbs.
25%of the total foliage of the tree or
shrub.
Trees or shrubs that have been blown Tree or shrub in place free of injury.
down or knocked over.
Trees or shrubs which are not adequately Tree or shrub in place and adequately
supported or are leaning over,causing supported; remove any dead or diseased
exposure of the roots. trees.
A-12 I/90 —
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 12 - ACCESS ROADS/EASEMENTS
Maintenance Conditions When Maintenance Results Expected
Component Defect Is Needed When Maintenance is Performed
General Trash and Debris Trash and debris exceeds 1 cubic foot Trash and debris cleared from site.
per 1,000 square feet,i.e., trash and
debris would fill up one standard size
garbage can.
Blocked Roadway Debris which could damage vehicle tires Roadway free of debris which could
(glass or metal). damage tires.
Any obstructions which reduce clearance Roadway overhead clear to 14 feet high.
above road surface to less than 14 feet.
Any obstructions restricting the access to Obstruction removed to allow at least a
a 10-to 12-foot width for a distance of 12-foot access.
more than 12 feet or any point restricting
access to less than a 10-foot width.
Road Surface Settlement, When any surface defect exceeds 6 Road surface uniformly smooth with no
Potholes, Mush inches in depth and 6 square feet in area. evidence of settlement, potholes,mush
Spots,Ruts in general,any surface defect which spots,or ruts.
hinders or prevents maintenance access.
Vegetation in Road Weeds growing in the road surface that Road surface free of weeds taller than 2
Surface are more than 6 inches tall and less than inches.
6 inches apart within a 400-square-foot
area.
Shoulders and Erosion Damage Erosion within 1 foot of the roadway more Shoulder free of erosion and matching
Ditches than 8 inches wide and 6 inches deep. the surrounding road.
Weeds and Brush Weeds and brush exceed 18 inches in Weeds and brush out to 2 inches in
height or hinder maintenance access. height or cleared in such a way as to
allow maintenance access.
A-13 1/90