HomeMy WebLinkAbout19. Drainage MemorandumCIVIL ENGINEERING
An Employee -Owned Company
LAND SURVEYING
MEMORANDUM
To: Olszewski, Massih & Maurer, P.C.
From: Tom Scott
Revised: June 18, 2012
Project: BNS Services, LLC
Subject: Drainage
Per your request we reviewed Article VII, Section 7-206 of the Garfield County Unified Land
Use Resolution of 2008, as Amended. It appears that the proposed Land use application for the
project is in conformance with the applicable land use regulations, as follows:
A. Site Design to Facilitate Positive Drainage.
The proposed contractor's yard has been laid out to provide positive drainage, as shown on
Erosion and sedimentation Control Plan. The region south of the proposed shop building is to
be graded to form a shallow drainage swale 10 feet away and parallel with the rear building
line. This swale has been design with a high point midway along its length to split and route
storm water around both the east and west side of the proposed building. Storm water
emerging from the swales is to continue northerly in sheet flow condition, across the proposed
gravel equipment storage areas. The storm water runoff will have the opportunity to seep down
into porous gravel voids and percolate into the soil beneath. Any remaining storm water runoff
will be intercepted by the existing ditches that are situated north of the proposed equipment
storage areas.
B. Coordination with Area Storm Drainage Pattern.
1. The proposed shallow drainage swale to be graded south of the proposed shop building
is to have a slope of 2 -percent, exceeding the minimum allowable slope of 0.75percent.
Anticipated flow velocities within the swale are to be less than 5 feet per second,
eliminating the need for energy dissipaters. Graded slopes adjacent to the proposed
shallow swale are to be graded at a 5:1 slope, far Tess than the maximum allowable
slope of 3:1.
2. Sub drains for the foundation of the proposed shop building are to be installed, and day
lighted as required. Details are to be prepared at the time of building permit submittal.
3. Drainage from the contractor's yard will not discharge onto adjacent Tots. The storm
water will remain on-site and ultimately reach the existing roadside ditch situated on
the north side of County Road 301.
1 51 7 BLAKE AVENUE, SUITE 1 01
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