HomeMy WebLinkAboutRIGDEN FARM, PARKSIDE EAST - PDP - 56-98F - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTThe proposed erosion control measures are presented on the Grading and Erosion Control
Plan located in the Appendix of this report.
In summary, the erosion control measures consist of
1. Temporary seeding on all of the land to be developed
2. Inlet protection at every inlet
3. Silt fences installed on the Eastern side of the development
4. Vehicle tracking control
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CONCLUSION
The runoff that will be produced by Parkside East at Rigden Farm has been accounted
for. More runoff will drain to the existing inlet at DP 5 than was previously calculated in
the Drainage Report for Rigden Farm Filing One. However, since the runoff from DP 5
will be combined with the runoff from DP 6 at DP 14c, we believe that it is a better
situation to take more runoff in the storm sewer than in Des Moines Drive.
EROSION AND SEDIMENT CONTROL
This report describes methods which are recommended to control wind erosion, water
erosion and sediment during and after the construction of drainage structures and site
grading.
DISCUSSION
The clearing and stripping of land for site grading, overlot grading, or for the construction
of drainage structures, may cause localized erosion rates with subsequent deposition and
damage to offsite properties. Uncontrolled, such erosion could destroy the aesthetic and
practical values of individual sites, and cause damage to downstream property.
In general, erosion and sediment control measures will consist of minimizing soil
exposure, control runoff across exposed areas, and sediment control at drainage
structures. Each of these measures is described below and should be utilized by the
developer and/or the contractor during any construction activity that occurs at this site.
GENERAL EROSION AND SEDIMENT CONTROL MEASURES
Minimizing Soil Exposure: Where practical, the construction area and duration of soil
exposure should be kept to a minimum. All other areas should have a good cover of
vegetation or mulch. Grading should be completed as soon as possible after
commencement. A temporary cover crop, a permanent vegetative cover crop, or other
landscaping should be established in the disturbed areas. Re -vegetation may consist of
native grasses, lawn grasses, or various winter wheat. Decorative rock, flower gardens, or
.shrubs may also be utilized in the final landscaping to cover the soil. Re -seeded areas
should be mulched with straw or hay to protect exposed soil until vegetation is
established.
EROSION CONTROL PLAN
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ONSITE RUNOFF
The runoff produced from the six onsite basins drains into the Rigden Farm Filing One
storm system and into Temporary Pond 22.
Sub -basin A- This sub -basin will drain northerly to Canby Way. The Drainage Report
for Filing One assumed 0.19 acres from this site would drain onto Canby
Way. Sub -basin A consists of 0.30 acres that will produce a slight increase
in runoff in Canby Way. The Filing One report had a total basin area of
2.79 acres for their subbasin 114. The revised area will be 2.90 acres or an
increase of only 4 percent and an increase in runoff of less than 0.5 cfs over
the Rigden Farm Filing One Drainage Report calculations.
Sub -basin B- This sub -basin will drain Easterly to the proposed Type R inlet located in
the eastern portion of the parking lot. Excess runoff that overtops the Type
R inlet will drain to the area drain at Design Point 5. The storm sewer from
the Type R inlet will convey the runoff to the existing area drain at DP5.
Sub -basin C- This sub -basin will drain easterly to the area drain located at the
northeastern part of the site. The area drain is connected to a storm sewer
that will convey the runoff to DP4.
Sub -basin D- This sub -basin will drain easterly to the area drain located at the eastern
part of the site. The area drain is connected to a storm sewer that will
convey the runoff to DP5.
Sub -basin E- This sub -basin will drain easterly to an existing area drain located at the
southeastern comer of the site. The area drain is connected to a storm
sewer that will convey the runoff to DP14c in the Drainage Report for
Filing One. The Filing One report calculated the 100 year runoff at this
design point to be 10.2 cfs. Our calculations have a total 100 year runoff of
16.01 cfs at this point. However, the runoff to DP6 is significantly less
than the Filing One Report. The runoff from DP5 and DP6 will be
combined at Filing One's DP14c.
Sub -basin F- This sub -basin will drain southerly to Des Moines Drive. The Drainage
Report for Filing One assumed 1.19 acres (subbasin 114b) from this site
would drain onto Des Moines Drive. Sub -basin F consists of 0.77 acres
that will produce less in runoff in Des Moines Drive. The Filing One
report had a total 100 yr runoff of 13.7 cfs compared to our calculated flow
of 5.38 cfs.
The proposed inlet at DP2 is a 10' Type R inlet. At design point 14c, the proposed runoff
will be less than the amount shown in the Filing One report.
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buildings and a clubhouse with a pool, The proposed development is accessed by Rigden
Parkway.
Major Drainage Basins
Parkside East at Rigden Farm lies within Reach 2 of the Foothills Basin.
Offsite Basins
Due to the construction of the adjacent streets, there are no offsite drainage basins that
enter this site.
nnsite Basins
Sub -basin A- This sub -basin consists of the northern 0.30-acre basin that drains onto
Canby Way. The basin proposed land use consists of one multi -family
building and a portion of one garage with the remainder being landscaped.
Sub -basin B- This sub -basin consists of the central 1.45-acre portion of the site that
drains to the proposed Type R Inlet located near the southeast corner of the
site. The basin proposed land use consists of several multi -family buildings
and garages, asphalt driveways and parking, with the remainder being
landscaped.
Sub -basin C- This sub -basin consists of the northeastern 0.13-acre portion of the site that
drains to a proposed area drain. The basin proposed land use consists of a
portion of a multi -family building and garage with the remainder being
landscaped.
Sub -basin D- This sub -basin consists of the eastern 0.31-acre portion of the site that
drains to a proposed area drain. The basin proposed land use consists of a
portion of a multi -family building and garage with the remainder being
either landscaped or the Clubhouse/Pool.
Sub -basin E- This sub -basin consists of the southeastern 0.27-acre portion of the site that
drains to a proposed area drain. The basin proposed land use consists of a
portion of several multi -family buildings and a garage with the remainder
being landscaped.
Sub -basin F- This sub -basin consists of the southwest 0.77-acre portion of the site that
drains to Des Moines Drive. The basin proposed land use consists of
several multi -family buildings and garages, asphalt driveways and parking,
with the remainder being landscaped.
OFFSITE RUNOFF
There is no offsite runoff that enters this site.
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FINAL DRAINAGE STUDY
FOR
PARKSIDE EAST AT RIGDEN FARM
Introduction
Parkside East at Rigden Farm is a proposed multi -family residential subdivision in the
City of Fort Collins, Colorado. The site is generally located on the South side of East
Drake Road midway between Timberline Road and County Road 9. The entire Rigden
Farm development consists of the majority of the North ''/z of Section 29, T7N, R68W,
Sixth Principal Meridian, Larimer County, Colorado. Parkside East at Rigden Farm
consists of approximately 3.24 acres located east of Rigden Parkway between Canby
Way and Des Moines Drive.
The purpose of this Final Drainage Study is to evaluate and present the drainage impacts
from Parkside East at Rigden Farm. In the evaluation, a site description of the project and
its relationship to the Rigden Farm. development will be presented. This Final Drainage
Study presents the changes to the developed flow condition and proposed improvements
to resolve the impact of the developed flow condition. This Final Drainage Report
demonstrates compliance with the approved final "Drainage and Erosion Control Report
for Rigden Farm Filing One, P.D.P," dated September 30, 1999, by JR Engineering.
Existin¢ Condition Descriotion
Currently the ground is gently sloping and covered with native grass. The site is bound by
Rigden Parkway on the West, Canby Way on the North, Des Moines Drive on the South
and Rigden Farm Filing One on the East.
In the present state, the site slopes from the West to the East at approximately 4..0%. The
current runoff drains East and South into a storm water quality pond that was built by the
developers of Rigden Farm Filing 1.
An area drain has been constructed at the southeast corner of the site with a 24-inch RCP
storm sewer to convey the runoff from the central portion of this site to Rigden Farm
Filing One's storm system. The developed runoff from this site has been accounted for in
the "Drainage and Erosion Control Report for Rigden Farm Filing One, P.D.P," dated
September 30, 1999, by JR Engineering. Please refer to attached excerpts from their
study that is located in Appendix A.
Drainage Impact
Proposed Site Conditions
Parkside East at Rigden Farm consists of 7 buildings with 6 dwelling units each, for a
total of 42 residential units. In addition to the 7 residential buildings, there are 8 garage
Table of Contents
Introduction................................................................................page 1
Existing Condition.........................................................................page 1
Drainage Impact...........................................................................page 1
Proposed Site Conditions
Major Drainage Basins
Offsite Basins
Onsite Basins
OffsiteRunoff............................................................................page 2
OnsiteRunoff..............................................................................page 3
Conclusion.................................................................................page 4
Erosion and Sediment Control ..........................................................page 4
APPENDIX A
Final Drainage Study
57ma ems, eo 80527
(970) 493-2808
57,4"X (970) 495- 9735
December 12, 2000
Project No. 0048
Mr. Donnie Dustin
City of Fort Collins
Stormwater Utility Department
700 Wood Street
Fort Collins, CO 80522
Dear Mr. Dustin:
On behalf of our client we are submitting the attached Final Drainage Study for
Parkside East at Rigden Farm. The purpose of this report is to evaluate and present the
drainage impacts from the proposed Construction of Parkside East at Rigden Farm. The
drainage report will present the developed flow conditions and proposed improvements.
The Final Drainage Study for Parkside East at Rigden Farm was prepared in
accordance with the provisions of the City of Fort Collins Storm Drainage Criteria —
revised January 1997.
Loonan and Associates, Inc.
James R. Loonan, P.E.
Registered Professional Engineer
Colorado P.E. 19195
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Prepared For
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Parkside Homes
u 1501 Academy Co rt
Snite 203
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Fort Collins, .CO 80524 •
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(970) 4Q7 9551.
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Date: December 12, 2000
P roject No 0048
Consulting Engineer:
Loonan and Associates, Inc.
1630 South College Ave
P.O. Box 270852
Fort Collins; CO : 80527