HomeMy WebLinkAbout72-91 - Ord. Amendments to Title 16 Plats & Subdivisions ORDINANCE NO� 72-471
APIENDPIENTES TO TITLE 16, MASON COUNTY CODE, PLATS AND
SUBD I V I SIONES
WIAEREAEV � the Board of Mason County Commissioners did on December
20, 1?71 , adopt a Plats and Subdivision Ordinance for Mason County ,
,with amendments on July 1 , 1974, May 10, 1976. April 30, 1979s
Sautember 14 , 1981 and April 1?, 1?89; anc-1
WHEREAS, the Board of Plason County Commissioners held a Public
Hearing on June 25 , 1991 for the purpose of considering several
amendments to the above listed Ordinance; and
WHEREASv it is now apparent that some revisions in the Code as
adc,Qted are required to better regulate road design an d
construction in subdivisions;
NOW. THEREFORE, BE IT ORDAINED. that Title 16, Plats and
Subdivisions of the Mason County Code be amended as follow s-
i
IQQO�070 CO, n�-'t— -t.' 2D—Standard s: - (a ) Minimum construction
standards appropriate to the locality, topography , soil conditions
and geology of %50n County pertaining to the construction of
roads , bridges, drains , culverts, monuments and other- reqUir-ei
improvements, have been prepared and adopted by the Board of County
Commissioners of Mason County ,
All improvements shall be constructed in conformity with sucir,
current standards as they may be amended by resolution of the Board
from time to time .
( b ) 1MprOVeM2nts on and construction of private or corporate
roads: shall comply with the minimum cons trucl:ion standards-s as
adopted by the Board .
if private or corporate roads are established in any plat ,
each lot shall have an equal , undivided , and indivisible interest
in such private or corporate roads ( see section 16.20.090 (d ) ) ,
16 , 28.040 Strgets—Private. Private streets and roads may be
allowed but thev must all conform to the current road standards as
adopted by the Board .
ChaAar oo
DESIGN 1-
E C I F I Q A T I[If FOR._fjLaOT ROADS
16 ,48.010 General requirements
i6. 48.020 Classification of roadways
16 ,48.030 Specific requirements
1648.040 Basic requirements
1648.010 General ReguiEements.
A plan and profile of the proposed road , showing the following
data , shall be submitted to the Public Works Director for approval
prior to construction .
MID-
The plan drawing ( s ) shall show,,
( a) Road alignment in stations of one hundred ( 100) foot intervals.
( b ) Bearings of the roadway centerline and a North arrow .
( c ) Curve data on all horizontal curves .
(d ) Right-of-way lines and widths for all roads and streets .
(e) . Topography within the right-of-way limits , including location
of all utilities
2
( f ) Contour lines at intervals of five ( 5) feet for rolling and
mountainous terrain , and two W feet for flat terrain
(g ) Labels or names on all streets and adjoining subdivisions.
( h) Typical roadway sections of proposed roads .
W Bridge plans, if applicable.
(J ) All natural flow and proposed drainage structures and flow
direction together with such controls , holding basins, or other-
design features necessary
Q ) Scale of mapa Suggested scale 1 " = 100 ' or 1 " w 50" �
EEP f i I e-
The profile of the roadway centerline shall show:
( a ) The original ground line at the centerline of the n2W roadway,
( b ) Stationing in intervals of one hundred ( 100 ) feet .
(c ) Control elevation on border of sheet,
(d ) Gradients in percent and vertical curve data .
(a ) Datum source used and all benchmark elevations.
W Profile scale shall be vertical 1" = 10 ' . horizontal 1" = 10'
or vertical 1" - 5 ' , horizontal 1 " = 50 ' �.
Note : profile scale shall be 100 ratio, horizontal to vertical .
Plan and profile sheets shall be submitted on 24" x 36" sheets , or
24" x 18%
16.48 0?0. Classification of_EgLaqdwa
L_ y_
cougly-An±eria A County road Primarily S2rVing through traffic
to , from and between principal population . commercial or industrial
areas; such arterial route5 are designated on the Count,,/' 5, Arterial
SystemR ( Such "County Arterials" may be "Major Arterials" ,
"Secondary Arterials" or.. "Collector Arterials" ". t1hese terms are, _-__;at
to be confused with the classification of Str2etS within the plat
below the grade of "(-ounty Arterial " ) ff
3
Primary Collector A road or street that carries traffic: fFom
Secondary Collectors, Local Access and marginal Access roads or
streets tc) the major system of arterial streets and highway5
Generally , Primary Collectors will serve an area containing more
than 100 lots.
Secondary Coll -- -gr A road or street that carries traffic from
Local Access and Marginal Access roads or street:5 to the Major
Collactors� Generally , Secondary Collectors will serve areas
containing more than 25 and less than 100 lotsm
Local Access R€?ad or Stre-et A road or street that serves primarily
a limited number of abutting properties. Generaly Lo l , cal Access
roads or streets will serve 25 or fewer lots.
NOTE , Probability and possibility of future function of street
will be of prime importance in establishing classifications Local
access roads or streets and secondary collectors shall be used
primarily to serve lots within the subdivisio-r-, and not afford
possibility of extension .
16, 48.032 Sped fREF Regu ' remlents
( a ) When a subdivision road intersects a County road or a state
highway an approved road access permit issued by the
Department of Public Works or the Washington State Department
of Transportation shall be required .
( b) Roads shall be constructed so as to minimize disruption of the
natural water flow which occurred prior to the road
construction . When it is necessary to collect surface water ,
concentration and collection points and oatbs shall be located
and constructed to restore the original drainage as nearly as
possible .
(c ) Evidence- of a recorded maintenance agreement shall be provided
for Drivate a reme rods. 'This agent shall run with the land and
shall describe levels of maintenance, management powers and
nf eor ov n cement prisios . The enfOrCMent provisions shall
provide adequate means Lca that the int(_-�nt of the
agreement is complied with by t h e road maintenance
administrators and the property owners .
(d ) Intersections shall be as nearly at right angles as is,
oracticable , but no less than 75 degrees or more than 105
degrees. volts with offsets of less than one hundred twenty--
five ( 125) feet shall be avoided .
I.
a) All construction , except as modified herein shall conform to
the Washington State Department of Transportation ' s Standard
Specifications for Roads, Bridges and Municipal Construction
and all subseouent amendments thereto .
W When a reasonable potential for future development within a
subdivision or an easement throu.rgh the property accessing
other unrelated property exists , the Public Works Director
and/or Planning Commission may, at the time of pFaliminary
plat approval , impose higher road classification standards to
accommodate future growth potential . Conversely , the Public
Works Director and/or Planning Commission may , at the time of
preliminary plat approval , assign lower road classification
standards when such action would better- serve the general
public interest.
( g ) Traffic signs, warning and regulatory , as required by the
Public Works Director and in conformity with the Manual for
Uniform Traffic Control Devices , current edition7 shall be
provided , Informational signs shall not be allowed within the
right-of-way of the road .
( h) All work must be inspected and approved by the Public Works
Director before successive elements of construction car-P begun ,
The Director shall be notified in advance of all ODerations
so as to afford adequate opportunity to inspect each element.
Anv work accomplished without adequate advance notice to and
approval by the Director may be rejected until proof
satisfactory to the Director has been produced . All costs of
determining the suitability of work so rejected and later
submitted for approval shall be borne by the developer and
shall be in addition to all other fees and inspection charges.
W All private roads constructed for any reason prior t:o the
initiation of the platting procedures shall be subject to all
the requirements herein when application is sought.
4' 0 12__Ra J. remen_t-La (See Footnotes Indicated )
This section specifie5 the minimum standards for the construction
of roads in subdivisions approved after June 25 , -1991 in Mason
Coun ty a Such roads shall be constructed according to their
classification or potential classification - County Arterial ,
Primary Collector, Secondary Collector, and Local Access Road or
Street .
5
Local SecondaFv pFimaFy County
Classification Accgs= I- lector Col a ems. - K -Val
Horizontal Curves
Max . Degree/min . rad .
Flat Terrain 26*/220 20*/287 10*/573 7*/819 '
Rolling Terrain 38*/!50' 26*/220 ' 15*/382' 10*/573'
Mountainous 08*/150 38*/i5o , 23*/249 ' 20*/2877
Suoerelevation 0.03t/f ft 0.05ft/ 0 ft .06f t/ t f C"08 f t/f
Crown O 03ft/ft 0.03ft/ft 0�03f t/f t 0103ft/ftt
* - Degree of centerline curvature
Gradient - maximum Percent
Flat Terrain 10% 0% 6% 67%
Rolling Terrain 12% 10% 8% B%
Mountainous 12% 12% 10% 10%
Bridges (see note 1 )
Clear width - min . 26ft. 28ft 30f t ( shoulder width ,
Design Load AASHTO FPS-20 HS-20 HS-20 HS-20
All bridges shall be of oar manent-type construction
Pavement ( see notes 2a, 3 and 4 )
Width min . ft. 20 20 22 22
Type min . BST Cl . "A" BST Cl , "A" BST Cl "A" BST Cl "A''
3-coat 3-coat 3-coat 3-coat
Stopping Sight Distance Min . /MPH
Flat Terrain 200/30 250/35 325/40 425/45
Rolling Terrain 160/25 200/30 250/35 325/0C)
Mountainous Terrain 120/20 160/25 200/30 250/35
Road Bad ( see note 2. 3 and 4 )
Shoulder to shoulder Width
Unpaved 27ft 29ft 31ft 35ft
(see note 5)
Paved Eft 28ft Soft 34ft
( see note 5),
Compacted Gravel Base 6" 6" 6" 91�
Crushed Surf . min . 2" 2" 2" 2"
Top Crs�
Right-of Way Minimum 40' 60' 60 ' 80 '
(see note 6)
Slopes - Steepest Allowable ( see notes 2b, 2c and 7 ) )
Downslope in cut 0: 1 3: 1. 30. 3: i
Section (ditch cut )
Downslope in Fill 1 1/2; 1 1 1/2: 1 1 1/2; 1 i 1/2: 1
Section
Backslooe in Cut i : 1 1 : i 1 1/2: 1 1 1/2: 1
6
Side Ditches - Minimum (see note 8)
Depth Below Finished
Shoulder 2 ' 2 2
Cul-de-sac
Pavement Diameter 54 ' 54 '
Roadway Diameter 60 ' 60' not allowed not allowed
( paved )
Roadway Diameter 62 ' 62' not allowed not allowed
(unpaved )
Right-of-way Diam. ft 100 100
Maximum Slope (Grade) 3% 3% V11 3%
Intersections
Minimum Angle, Deg . 75 75 75 75
Minimum Shoulder Rad . 20' 2Y V0 , 55 '
Minimum FTC'41 Radius 30 ' 30 ' 40 ' 70 '
Culverts
All culverts shall be sized adequately to accommodate runoff
and to facilitate cleaning and maintenance ( 18 ' minimum
diameter for cross culverts, 12" minimum diameter for access
driveways ) . In critical situations , the Director of Public
Works may require submission of a hydrologic survey of the
drainage area for the proposed culvert .
Culverts shall be t ,truce i
corrugated aluminum OF galvanized corrugated steel 0 r
equivalent . The Director of Public Works may require that in
locations where corrosive soil or water may be present , that
the culvert be coated with asphalt
Nolen:
1 � All bridges shall have a minimum clear width between curbs
equal to or greater than the finished shoulder width of the
adjacent roadway� All bridges shall be designed by a
professional structural engineer and shall be s,,ibject
design review and approval by the Director of Public Work5 .
2. ( a ) Roadbed on all curves sharper than ten degrees and flatter
than fifteen degrees shall be widened two feet . Curves of
fifteen degrees and over shall be widened three feet .
Widening shall be added to the inside edge of the CUrV2.
( b ) All fills less than I feet in height from toe to shoulder
shall be no steeper than _ feet horizonta f F l to 1. foot vetical
13: 1 ) ; fills 3 to 10 feet shall be widened one foot on each
shoulder; fills over 10 feet shall be widened two feet on each
shoulder.
7
fc ) Cuts of less than 5 feet above the shoulder shall �De
sloped at 2: 1 .
( a) When raQ u i red bituminous surface trey t man t sh a! -I be
applied as follows ;
Two coats initially and a third coat the following year.
(see Specifications for seasonal restrictions ) .
( b) in lieu of 3-coat BST the aoplication of 1 1/2" compacted
thickness of asphaltic concrete class "B" may be substituted .
Laid on compacted 2" top course without prime coat .
Private roads serving subdivisions with a total of five to
twenty-five (25 ) lots or parcels not. be required to
provide pavement .
(a ) Minimum shoulder widths will be , in each case, dictated
by anticipated traffic demands and County standards for
arterials.
RA County "arterial " standards will be required for all
arterial routes for which construction or reconstruction is,
necessitated by the proposed division . Plinimum stipulated
right-of-way widths will be required in all instances ,
6 . Right-of-way shall contain all cut and fill slopes; amceptions
may be permitted when coordinated with site grading .
7. Backslopes may be steepened if actual soil tests conclusively
indicate that material will conform permanently to a steeper
slop Slopes muk,-,t be flattened as required to prevent
erosion , caving and slumping .
B. Side drainage ditches on steep grades will r2QUire SgeCial
analysis and may require special design and construction to
prevent erosion and/or flooding .
1 This title is amended and shall be in full force . and effective
2 this date.
3 DATED this Z5- day of 1-9-9,0
4 BOARD OF COUNTY COMMT SIGNERS
5 mi::=
7 Cha rma.n
�r-
9 ommissioner
10 \
11 Commissioner � 1
12 ATTEST
13
14 C erk of the B c�aj d
15 APPR UE AS1 TO 0�?�,
IX
16
17 Prosecuting attorney of Mason County