HomeMy WebLinkAboutSmall Parcel Stormwater Site Plan - BLD Plot / Site Plans SMALL PARCEL STORMWATER SITE PLAN
Bruce D Larson/ClfM ME10K
Mason County Tax Parcel#32236-75-00060
5i11 ADW-E� - g98'LI F.5R106
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This site is on a 5 acre parcel located near the South Shore of Hood Canal approximately 300+feet
northeast of East State Route 106, near mile marker 10. The lot is partially forested and slopes
northwesterly toward the Hood Canal. Some of the varied terrain exceeds a slope of 40%.
Approximately 1/2 acre of the lowest elevation of this parcel was previously cleared and is a septic drain
field easement for three adjacent parcels. Approximately 1/3 acre has been cleared approximately 90
feet uphill from the abovementioned septic easement where the building site is situated.Trees and
other native vegetation will be left intact surrounding the building site and for approximately 90 feet
below the building site.
There is an existing paved easement road approximately 200 feet x 18 feet(3,600 square feet)and an
existing gravel easement road approximately 175 feet x 15 feet(1,125 square feet)on the parcel leading
up to the building site.This easement road has an approximate 15%grade.The driveway from the
easement to the house will be approximately 65 feet x 15 feet(975 square feet).A parking area shall be
approximately 25 feet x 25 feet(625 square feet). Both the driveway and parking area will be fairly level.
The house will have a surface area of approximately 2,432 square feet. The total impervious surface
area is approximately 8,757 square feet.
Stormwater flows will be dispersed through vegetation and to an infiltration pit.To avoid saturating soils
near the foundation of the house, roof drains shall be directed via gutter and downspouts, along with
footing drains to tight lines extending to the infiltration pit. Infiltration pit shall be located 30 feet
northeast of the drain field. The driveway and parking areas are relatively flat,therefore the runoff from
these areas can simply be allowed to sheet-flow to the northwest. Runoff from the gravel easement
road shall be directed to various natural vegetated areas, with riprock dams being used to inhibit,
disperse and prevent concentrated runoff.
In order to prevent erosion and trapped sediments within the project site,the following Best
Management Practices (BMPs)will be used approximately as shown on the Erosion and Sediment
Control (ESC) plan.
• Dispersion trenches shall be placed according to flow control requirements.Areas accepting
sheet-flow from driving and parking area (that are not being left in native vegetation)will be
seeded and mulched.
• Water will not be allowed to point discharge onto slopes.
• A rock-lined ditch will intercept and direct water from steeper portions of the easement to
dispersal areas along the slope.
• Silt fencing may be placed at lower edge of clearing, as needed.
• Mulch will be spread over cleared areas of the site when not being worked, as needed.
• Mulch will consist of air-dried straw.