HomeMy WebLinkAboutFile Documents.395 Thunderbowl Ln.0255.2018 (13).ARBKWoody Creek Engineering, LLC
PO Box 575
Woody Creek, CO 81656
MEMO Ditch to Pipe 20190527
Memorandum
To: City of Aspen Engineering Department
From: Josh Rice, P.E.
CC:
WCE Project
Number: 0049
Date: May 27, 2019
Re: Roadside Ditch and 15” RCP Capacity Calculations, Lot 7 Thunderbowl
This memorandum describes the analysis and calculations for the existing roadside ditch at Lot 7
Thunderbowl and the analysis and calculations for the proposed 15” RCP pipe at the driveway
crossing. The proposed plans have been updated to show a 15” RCP pipe rather than a 12” CMP
pipe.
Existing Roadside Ditch Capacity
Woody Creek Engineering, LLC (WCE) analyzed the cross-sectional flow capacity of the exist-
ing roadside ditch at the cross-section highlighted in Figure 1, below.
Figure 1. Roadside Ditch Cross-Section Location
1/11/20185/27/2019
06/18/2019
Reviewed by Engineering
06/28/2019 1:49:32 PM
"It should be known that this review shall not
relieve the applicant of their responsibility to
comply with the requirements of the City of
Aspen. The review and approval by the City is
offered only to assist the applicant's
understanding of the applicable Engineering
requirements." The issuance of a permit based
on construction documents and other data shall
not prevent the City of Aspen from requiring the
correction of errors in the construction
documents and other data.
Page 2
May 27, 2019
Re: Roadside Ditch and 15” RCP Capacity Calculations, Lot 7 Thunderbowl
MEMO Ditch to Pipe 20190527
WCE then analyzed the longitudinal slope of the ditch and used Hydraflow Express to analyzed
the cross-sectional flow capacity. The roadside ditch has a flow capacity of 21.01 cfs flowing
98% full. Figure 2, provides the channel report results.
Figure 2. Cross-Sectional Flow Calculation
06/18/2019
Page 3
May 27, 2019
Re: Roadside Ditch and 15” RCP Capacity Calculations, Lot 7 Thunderbowl
MEMO Ditch to Pipe 20190527
WCE then analyzed the pipe cross-section required to provide a minimum of 21.01 cfs of flow
capacity. A 15” RCP culvert located under the driveway will provide 22.36 cfs flowing 80%
full. Figure 3, provides the channel report results.
Figure 3. 15" RCP Flow Capacity Calculations 06/18/2019