HomeMy WebLinkAboutLARIMER COUNTY COMMUNITY CORRECTIONS FACILITY - SITE PLAN ADVISORY REVIEW - 19-03 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTNo Text
Drainage & Erosion Control Study
BEYOND ENGINEERING Larimer County Community Corrections Facility
1. City of Fort Collins Stormwater Drainage Design Criteria and Construction Standards
City of Fort Collins, Colorado, April, 1997.
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BE Y O N D E N G IN E E a ING Larimer County Community Corrections Facility
5.0 CONCLUSIONS
5.1 Drainage Concept
The proposed drainage concepts presented in this study and shown on the drainage
plans adequately provide for the conveyance of developed runoff from the
proposed development.
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Drainage & Erosion Control Study
BEYOND ENGINEERING Larimer County Community Corrections Facility
4.0 DEVELOPED DRAINAGE CONDITIONS
4.1 General Concept
The developed runoff from basins 100 through 103 sheet flows to the on -site
detention pond. This detention pond discharges to Midpoint Drive. The remaining
areas of the project site discharge to the surrounding area.
4.2 Basin Descriptions
4.3 Detention Pond Design
The on -site detention pond was designed to attenuate the 100-year developed
runoff to the 10-year historic rate of 0.98 cfs.
The emergency overflow spillway was designed to spill directly to Midpoint Drive.
The crest of the emergency overflow spillway is set at 4907.24.
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HISTORIC DRAINAGE SUMMARY CHART
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FCO259
rNICUrENDrainage & Erosion Control Study a E Y O N O ENGINEERING Larimer County Community Corrections Facility
3.0 HISTORIC DRAINAGE BASINS
3.1 Major Basin Description
The project site lies within Poudre River Basin. The project site is not within the
limits of either a FEMA or City of Fort Collins designated floodplain.
3.2 Existing Site Drainage
Local undeveloped runoff flows overland to Midpoint drive from basin H-100 and
to the southeast from basin H-100 Refer to Figure 2).
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BEYOND E N G 1 N E BRING
Drainage & Erosion Control Study
Larimer County Community Corrections Facility
2.0 METHODOLOGY
2.1 Compliance with Standards
The drainage study that follows was prepared in accordance with the requirements
and procedures for storm drainage design set forth in the City of Fort Collins
Stormwater Drainage Design Criteria and Construction Standards (Dated: April
1997), and herein after referred to as Criteria.
2.2 Analytical Methods
The rational method was used to estimate the historic and developed runoff from
the 10-year and 100-year design storm return periods. The design storms were
selected from Table 3-1 of the Criteria for a Public Building Area land use.
The rational method is widely accepted for drainage design involving small
drainage areas (<160 acres) and short times of concentration. It relates peak
discharge to the runoff coefficient, rainfall intensity, and drainage area. The rainfall
intensity and runoff coefficients were taken from Table 3-3 of the Criteria. This
method is ideal for storm sewer sizing and simple detention pond sizing or design
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situations where only the peak flow rate and/or the total volume of runoff are
needed.
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Larimer County Community Corrections Facility SHEET NUMBER
P*4 Vicinity Map 1
BEYOND E061NEERINO Figure 1.
OF 1 SHEETS
�M n X FAX FaRr M�TLOW PREPARED FOR: Larimer County DATE SUBMITTED: 05/19/03 SM roe NUMBER
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Drainage & Erosion Control Study
BE Y O N D E N G IN E E R ING Larimer. County Community Corrections Facility
1.0 INTRODUCTION
1.1 Site Location
The proposed Larimer County Community Corrections Center will be located on a
portion of Centerpoint Second Filing and Lot 2, Centerpoint Park #3 (Refer to
Figure 1, Vicinity Map). More specifically, the project site is bounded to the north
by Midpoint Drive; to the east by the Larimer County Detention Facility (existing);
to the south by the Burlington Northern Railroad; and to the west by undeveloped
land and the Burlington Northern Railroad. The project site will cover
approximately 2.84 acres.
1.2 Existing Site Description
The project site is undeveloped. The existing site slopes toward the southeast at an
average grade of 1.50%.
11 According to the Soil Survey of Larimer County Colorado Area. Colorado, the
on -site soils consist of Caruso Loam, 0 to 1 percent slopes. Runoff from this soil
type is slow and the hazard of erosion is sight. Refer to Appendix A for more
information.
1.3 Proposed Project Description
The proposed project will consist of the Larimer County Community Corrections
Facility, parking, associated landscaping, and utilities (e.g., domestic water,
sanitary sewer, and storm drain).
Access to the project site will be provided from Ndpoint Drive.
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Drainage & Erosion Control Study
Larimer County Community Corrections Facility
BEYOND ENO I N EERING
TABLE OF CONTENTS
PAGE
1.0.
INTRODUCTION........................................................................................................1
1.1 Site Location.....................................................................................................
1
1.2 Existing Site Description...................................................................................
1
1.3 Proposed Project Description............................................................................1
2.0
METHODOLOGY.......................................................................................................2
2.1 Compliance with Standards...............................................................................
2
2.2 Analytical Methods...........................................................................................
2
3.0
HISTORIC DRAINAGE CONDITIONS.....................................................................
3
3.1 Major Basin Description....................................................................................
3
3.2 Existing Site Drainage.......................................................................................
3
4.0
DEVELOPED DRAINAGE CONDITIONS.................................................................
4
4.1 General Concept...............................................................................................
4
'
4.2 Basin Descriptions.............................................................................................
4
4.3 Detention Pond Development and Design..........................................................
4
5.0
CONCLUSIONS..........................................................................................................5
5.1 Drainage Concept.............................................................................................
5
1 REFERENCES............................................................................................................. 6
APPENDIX A -
APPENDIX B
Soils Information
Project Site Hydrology
-
• Estimated Runoff for Historic Conditions
• Estimated Runoff for Existing Conditions
APPENDIX C -
Hydraulic Calculations
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• Culvert Design
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APPENDIX D -
Detention Pond Design
APPENDIX E -
Charts, Tables & Graphs
BACK POCKET
- Drainage and Erosion Control Plan (Sheet DR01)
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LARIMER COUNTY
CORRECTIONS CENTER
DRAINAGE &
EROSION CONTROL STUDY
for
Delta Construction, Inc.
208 Racquette Drive
Fort Collins, Colorado 80524
0
Nolte Associates, Inc.
1901 Sharp Point Drive, Suite A
Fort Collins, Colorado 80525
(970) 221-2400
May 19, 2003