HomeMy WebLinkAboutUNIVERSITY CENTER PUD (UNIVERSITY MALL REDEVELOPMENT) - FINAL - 2-96A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTM!
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APPENDIX A
MAPS AND FIGURES
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1' 6.2 Irrigation Ditches
The development of University Center PUD does not change the outfall into the Sherwood
Lateral. (See above for discussion.)
6.3 Ditch Company Approval
Because this is the existing outfall for the drainage from this area and the proposed drainage
plan does not impact the flows currently released into the Sherwood Lateral, ditch company
approval is not required.
6.4 Maintenance Agreements
The developer will be responsible for the maintenance of all temporary drainage structures.
7. REFERENCES
1. "Preliminary Drainage and Erosion Control Report - University Center P.U.D.",
prepared by JR Engineering, Ltd., Revised March 11, 1996.
2. City of Fort Collins, "Storm Drainage Design Criteria and Construction Standards",
(SDDCCS), dated May, 1984.
3. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria
Manual", Volumes 1 and 2, dated March, 1969, and Volume 3 dated September,
1992.
4. "Spring Creek Master Drainageway", prepared by Engineering Professionals, Inc.,
dated March, 1988.
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from his operations under these specifications on right-of-way or elsewhere.
' 5.6 Tracking Mud on City Streets
' It is unlawful to track or cause to be tracked mud or other debris onto city streets or rights -
of -way unless so ordered by the Director of Engineering in writing. Wherever construction
' vehicles access routes or intersect paved public roads, provisions must be made to minimize
the transport of sediment (mud) by runoff or vehicles tracking onto the paved surface.
Stabilized construction entrances are required per the detail shown on the Plan, with base
material consisting of 6" coarse aggregate. The contractor will be responsible for clearing
mud tracked onto city streets on a daily basis.
5.7 Maintenance
All temporary and permanent erosion and sediment control practices must be maintained and
repaired as needed to assure continued performance of their intended function. Straw bale
dikes will require periodic replacement. Sediment traps (behind hay bale barriers) shall be
cleaned when accumulated sediments equal about one-half of trap storage capacity.
Maintenance is the responsibility of the developer.
5.8 Permanent Stabilization
A vegetative cover shall be established within one and one-half years on disturbed areas and
soil stockpiles not otherwise permanently stabilized. Vegetation shall not be considered
established until a ground cover is achieved which is demonstrated to be mature enough to
control soil erosion to the satisfaction of the City Inspector and to survive severe weather
conditions.
6. MISCELLANEOUS
6.1 Variances
There are no variances requested with the development of the University Center PUD.
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5.3 Soil Description
In accordance with the Soil Conservation Service's (SCS) "Soil Survey of Fort Collins Area,
Colorado" (copy reproduced in Appendix), the soils on -site consist of the following:
Rainfall Wind Hydrologic
Soil Designation Erodibility Zone Erodibility Zone Soil Group
Nunn clay loam Slight to Moderate Slight to Moderate C
(See Section 1.3 for further discussion of soils found on this site.)
5.4 Erosion And Sediment Control Measures
Erosion and Sedimentation will be controlled on -site by the use of straw bale barriers and
inlet protection (gravel Filters). (See Appendix for Cost Estimate and the attached "Drainage
and Erosion Control Plan" for details.)
The measures are designed to limit the overall sediment yield increase due to construction as
required by the City of Fort Collins. A construction schedule is contained in the Appendix
and shown on the "Drainage and Erosion Control Plan" which shows the overall time frame
for construction activities.
Silt fence will be utilized in limited areas adjacent to any stockpiles that are•created during
grading, if required.
5.5 Dust Abatement
During the performance of the work required by these specifications or any operations
appurtenant thereto, whether on right-of-way provided by the City or elsewhere, the
contractor shall furnish all labor, equipment, materials, and means required. The Contractor
shall carry out proper efficient measures wherever and as necessary to reduce dust nuisance,
and to prevent dust nuisance, and to prevent dust which has originated from his operations
from damaging crops, orchards, cultivated fields, and dwellings, or causing a nuisance to
persons. The Contractor will be held liable for any damage resulting from dust originating
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Subbasins Q (100)
(CFS)
Without Detention
Existing Flows EEX24,E13-18 30.47
Developed Flows DEX1,D1-D6 45.38
Difference -14.91
With Proposed Parking Lot Detention
Existing Flows EEX2-4,E13-18 30.47
Developed Flows DEX1,D1-D6 29.25
Difference 1 1 1.22
5. EROSION CONTROL
5.1 Introduction
This section represents the Erosion Control Report for the University Center PUD and was
prepared to meet the regulatory requirements of the City of Fort Collins, Colorado. This
report was prepared following the guidelines and regulations within the SDDCCS Manual.
5.2 General Description
The total site is comprised of approximately 14.8 acres. The proposed improvements
comprise portions of the westerly and southwesterly portions of the site.
The general topography of this site consists primarily of existing asphalt parking lot, buildings,
and curb, gutter and sidewalk. The southwest comer and westerly portion of the site consist
of poorly to very poorly covered range type land. The slopes range from 0.5 to 3 percent.
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4.3
4.4
proposed retail building and the proposed addition to the south side of King Soopers.
In addition, the finished floor for the proposed retail building has been set two feet (2')
above the area inlet grate to allow for a maximum depth of one foot of ponding plus
one foot of freeboard. (See Appendix for calculations, Drainage Plan for additional
information, and below for further discussion.)
South Parking Detention Area
The South Parking Detention Area is located between the proposed retail building and
McDonalds. Flows are directed to this area from a portion of the proposed retail
building and the surrounding parking area. This detention area has a proposed sump
condition area inlet that acts as the outfall. The release from this pond will be
controlled by an orifice plate to be installed on the outfall pipe for said inlet. This area
has been graded to provide for detention with the maximum ponding depth of 1 foot
at the inlet location. In order to control this depth, the surrounding parking lot has
been graded to allow for the overflow (weir) to be released into the parking areas on
the north and south sides of the existing McDonalds. (See Appendix for calculations,
Drainage Plan for additional information, and below for further discussion.)
Flow Rates Released to College Avenue Outfall System - Existing and Developed
In order to meet the constraint for this site to release the flows into the College
Avenue outfall system at the 2-year historic (existing) rate for the currently un-
developed southwest portion of the site and the 100-year historic (existing) rates for
the remainder of the site, the total existing flows and the total developed flows have
been computed.
The following table summarizes these flows:
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4.2 Southwest Parking Detention Area
The Southwest Parking Detention Area is located in the parking area in the southwest
corner of this site. Flows are directed to this area from a small off -site area
(Burlington Northern), a portion of the proposed storage unit area, a portion of the
proposed retail building and the parking area in the southwest corner of this site. This
detention area has a proposed sump condition area inlet that acts as the outfall. The
release from this pond will be controlled by an orifice plate to be installed on the
outfall pipe for said inlet. This area has been graded to provide for detention with the
maximum ponding depth of I foot at the inlet location. In order to control this depth,
the parking lot has been graded to provide for an overflow (weir) between the
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' developed portions of the University Center PUD and the 2-year historic (existing) release
' rate from the currently undeveloped southwest corner of the site. (It was agreed that the
volume issue would not be considered with this system as there are really no alternatives
available. Note: The increase in flows to the system in College is in lieu of increasing the
flows to the rear of the site and into the Sherwood Lateral.) These two detention ponds are
„. located in the Southwest Parking Area and the South Parking Area.
In addition, the detention area proposed in the Preliminary Drainage Report for this site is no
longer required as the revised runoff rates and volume are less than the 100-year existing
values. (See Section 4.1 below for further discussion.)
4.1 West Parking Detention Area (Proposed in Preliminary Report but Not
Required)
In the Preliminary Report for this site, the developed runoff from the rear of this site
was greater than the existing. Therefore, preliminary calculations were prepared to
show that the routing of the flows from this area through the curb cuts between the
storage buildings (the access points from the parking area along the west side of the
mall) would actually provide adequate detention to reduce the flow rate to less than
historic. At the same time, the volume of flows released in this area was calculated
as less than historic.
As a result of some changes to the rear of the University Center PUD site, the final
configuration of the site has resulted in a smaller area of the developed site being
routed to the northwest comer of subject site.
The following tables summarize the information:
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4.
3.9 Storm Sewer Design
There are two (2) underground storm sewer systems proposed with the development of
University Center PUD. These storm sewer systems are located in the southwest portion of
the site. They will be connected to two separate parts of the existing underground storm
sewer system (College Avenue Collection System). (See Appendix for calculations.)
3.9.1 Southwest Parking Detention Area
This storm sewer system has been designed to carry the flows from the Southwest
Parking Detention Area to the existing storm sewer outfall system.
3.9.2 South Parking Detention Area
This storm sewer system has been designed to carry the flows from the South Parking
Detention Area to the existing storm sewer outfall system.
;111#M�"l Q STool,
PIPE
MINIMUM
DESIGN
REACH DESCRIPTION DIAMETER
SLOPE
DISCHARGE
inches
%
cfs
From Southwest Parking Detention Area
Area Inlet to Existing System
15
0.1
2.18
From South Parking Detention Area
Area Inlet to Existing Inlet
1 15
0.1
1.75
DETENTION PONDS (PARKING AREA)
There are two (2) detention ponds proposed with the development of the University Center
PUD. These detention ponds have been designed to limit the outfall into the existing College
Avenue system to the total of the 100-year historic (existing) release rate from the currently
10
TADL
......
14 AIti
A L
Tc (100) Q (2)
Q (100)
DESIGN
AREA
AREA
C10
C100
Tc (2)
POINT
DESIG.
(ACRES)
CFS)
(CFS)
DI
0.43
0.861
1.00
5.0
10.0
2.07
3.0
D2
0.58
0.781
0.98
5.0
10.0
2.53
4.0
D3
0.26
0.831
1.00
5.0
10.0
1.21
1.8
D4
1.26
0.901
1.00
5.0
10.0
6.30
8.9
DEXI
0.25
MO
0.63
5.0
10.0
0.70
1.11
D5
1.37
0.82
1.00
5.0
10.0
6.26
9.7
DEX1,D5
1.62
'0.77
0.96
7.5
10.0
6.17
11.0
D6
2.30
0.94
1.00
5.0
10.0
12.111
16.3
D7
0.74
0.95
.1.00
5.01
10.0
3.921
5.2
D8
2.45
0.95
1.00
5.01
10.0
12.991
17.4
D7,D8
3.19
0.95
1.00
5.0
10.0
16.92
22.71
D9
1.04
0.94
1.00
7.5
10.0
4.81
7.4
DEX2
0.36
0.50
0.63
5.0
10.0
1.00
1.6
D10
0.27
0.37
0.46
11.5
11.5
0.42
0.83
DEX2,D10
0.63
0.44
0.55
11.5
11.5
1.17
2.3
DEX2,D9,D10
1.67
0.75
0.94
11.5
11.5
5.27
10.53
DEX2,D7,D8,
4.83
0.88
1.00
11.5
11.5
18.02
32.6
D9,D10
D 11
0.04
0.95
1.00
5.0
10.0
0.21
0.2
D 12
0.03
0.95
1.00
5.0
10.0
0.16
0.21
3.7 Allowable Street Flow Capacities
The University Center PUD does not affect flows on any existing or proposed streets.
Therefore, calculations for allowable street capacities for the surrounding, existing streets are
not included.
3.8 Inlet Design
There are three (2) sump condition area inlets proposed with the University Center PUD.
These inlets (standard Type C) are located in the southwest and south-central portions of this
site. (See Section 4. Detention Ponds for discussions relating to these inlets.)
9
where Q is the flow in cfs, A is the total area of the basin in acres, Cf is the storm frequency
adjustment factor, C is the runoff coefficient, and I is the rainfall intensity in inches per hour.
The frequency adjustment factor, Cb is 1.0 for the initial 10-year storm and 1.25 for the major
100-year storm.
The appropriate rainfall intensity information was developed based on rainfall intensity
duration curves in the SDDCCS Manual.
In order to utilize the rainfall intensity curves, the time of concentration is required. The
following equation was used to determine the time of concentration:
t,=t,+tt
(2)
where t, is the time of concentration in minutes, t; is the initial or overland flow time in
minutes, and t, is the travel time in the ditch, channel, or gutter in minutes. The initial or
overland flow time is calculated with the SDDCCS Manual equation:
t, = [1.87(1.1 - CCf)L0.5]/(S)0.33
(3)
where L is the length of overland flow in feet (limited to a maximum of 500 feet), S is the
average slope of the basin in percent, and C and Cf are as defined previously.
All hydrologic calculations associated with the sub -basins are attached in the Appendix of this
report. Table 3.1 provides a summary of the design flows for all Subbasins and Design Points
(DP's) associated with this site.
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Runoff from Subbasin D8 is conveyed westerly to the proposed parking lot, diverted
to a proposed weir (curb cut) along the west side of said the parking area, conveyed
into the proposed storage unit area, diverted northerly and conveyed to the existing
swale along the rear of Montgomery Wards.
Runoff from Subbasin D9 is conveyed northerly in a swale through the center of the
proposed storage units and outfalls into the existing swale along the westerly side of
Montgomery Wards. Said swale outfalls into the Sherwood Lateral. (See above for
discussion.)
The runoff from Subbasin DEX2 is routed onto Subbasin D10 via overland flow.
Runoff from Subbasin D10 is conveyed northerly in a swale just east of the westerly
boundary of this site. This area is over an existing City of Fort Collins' Light and
Power electric duct bank and consists of a landscape strip along the westerly property
line and an all-weather surfaced (gravel) access road for said electric duct bank. Said
swale outfalls into the Sherwood Lateral. (See above for discussion.)
The runoff from the combination of Subbasins DEX2, and D7, D8, D9 and D10 is
routed to the existing swale along the west side of Montgomery Wards and outfalls
into the Sherwood Lateral (which is the existing outfall for this area) as stated in the
previous paragraphs. Because the Sherwood Lateral is the outfall for the westerly
portion of this site, the flows (release rate and volume) have been limited to equal or
less than the existing flows for this area.
3.6 Hydrologic Analysis of the Proposed Drainage Conditions
The Rational Method was used to determine both 10-year and 100-year peak runoff values
for each Subbasin. Runoff coefficients were assigned utilizing Table 3-2 of the SDDCCS
Manual.
As stated above, the Rational Method was used for all hydrologic analyses for the project site.
The Rational Method utilizes the SDDCCS equation:
Q = CrCIA
7
(1)
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Note: The drainage for the portion of this site between the existing mall and College Avenue
(north of McDonalds) does not change as a result of this project. Therefore, developed flows
were not calculated for these areas nor described below.
Runoff from Subbasin D1 is conveyed into three (3) existing sump condition area
inlets adjacent to the north side of McDonalds via sheet flow.
Runoff from Subbasin D2 is conveyed into an existing sump condition area inlet
adjacent to the south side of McDonalds via sheet flow.
Runoff from Subbasin D3 is conveyed into an existing sump condition area inlet in
the parking area south of McDonalds via sheet flow.
Runoff from Subbasin D4 is conveyed into a proposed sump condition area inlet to
be located east of the proposed building in the southwest portion of this site via sheet
flow.
The runoff from Subbasin DEX1 is routed onto Subbasin D5 via overland flow.
Runoff from Subbasin D5 is conveyed into a proposed sump condition area inlet to
be located west of the proposed building in the southwest portion of this site via sheet
flow.
The runoff from the combination of Subbasins DEXI and D5 are routed to the
proposed sump condition area inlet as previously stated.
Runoff from Subbasin D6 is conveyed to an existing sump condition inlet on the west
side of King Soopers.
Note: Said outfall system currently has some capacity problems. Therefore, the
runoff for these areas will be restricted. (The currently undeveloped area in the
southwest corner of this site will be restricted to the 2-year historic release rate. The
remainder of the site will be restricted to a release of equal to or less than the existing
100 year release rate.) See below for further discussion.
Runoff from Subbasin D7 is conveyed westerly to the proposed parking lot, diverted
to a proposed weir (curb cut) along the west side of the parking area, conveyed into
the proposed storage unit area, diverted northerly and conveyed to the existing swale
along the rear of Montgomery Wards.
3.2 Exterior Flows
Exterior flows enter this site from the west (the existing Burlington Northern Railroad). All
lands lying within these areas have been assigned land use characteristics reflecting their
current, developed conditions. These areas are identified on the attached "Drainage Plan" and
calculations are included in the Appendix of this report.
3.3 Onsite Flows
Flows within this site will take the form of overlot and swale flow. The existing drainage
patterns have been maintained where possible. All grading has been designed to carry flows
away from structures to the proposed drainage facilities.
3.4 General Flow Routing
The final drainage pattern for this area has been developed to provide a drainage system that
is compatible with the surrounding area. This has been accomplished by utilizing existing
drainage patterns to the extent possible and routing flows to limit the amount of required
drainage facilities.
The proposed drainage facilities for this site consist of existing area inlets and outfall pipes,
proposed inlets and pipe in the southwest comer of the site, and proposed parking lot
detention for the southerly and/or easterly portions of the site. (See below for further
discussion.)
The proposed drainage system meets the requirements for providing drainage relief by
reducing the impact of the flows generated by the re -development of portions of this site on
downstream areas (restricting -release rates to existing) and meets the criteria in the SDDCCS.
(See attached "Drainage Plan" for the location of all drainage facilities.)
3.5 Proposed Drainage Plan
A qualitative summarization of the drainage patterns within each sub -basin and at each design
point is provided in the following discussion paragraphs. Discussions of the detailed design
of drainage facilities identified in this section are included in Sections 3.7.
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3.
I
II
I I
11
'lE �113L1;+ .3
H.S ;E (j)E C X11S
AREA
AREA
CIO
C 100
Tc 10
Tc 100
Q 10
Q 100
DESIG.
ACRES)
(MIN)
(CFS
CFS
EX2
0.18
0.50
0.63
5.0
10.0
0.50
0.8
16
1.64
0.211
0.261
12.3
12.3
1.40
2.8
EX2,E16
1.82
0.241
0.301
12.3
12.3
1.771
3.5
EX3
0.23
0.501
0.631
5.0
10.0
0.641
1.0
17
1.39
0.721
0.90
6.1
10.0
5.27
8.8
EX3,E17
1.62
0.691
0.86
6.1
10.0
5.88
9.91
EX4
0.06
0.501
0.63
5.0
10.0
0.17
0.2
18
0.67
0.841
1.00
5.0
10.0
3.13
4.7
EX4,E18
0.73
0.81
1.001
5.0
10.0
3.301
5.2
EX2-4,
6.02
0.62
0.78
12.3
12.3
15.26
30.4
13-18
EX5
0.19
0.501
0.631
5.0
10.0
0.531
0.85
19
5.15
0.79
0.991
11.0
10.0
17.41
36.2
EX5,E19
5.34
0.78
0.97
15.0
11.9
15.56
34.4
DEVELOPED FLOWS
3.1 Method
The Rational Method was used to determine both the 10-year and 100-year flows for the sub -
basins indicated in this drainage report. A detailed description of the hydrologic analysis is
provided in Section 3.6 of this report.
The historic (e)dsting) flows for this site are included as part of this report. The resulting 10-
and 100-year runoff values were used to compute discharges at specific design points.
4
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Irear of the Montgomery Ward property. (To our knowledge, this swale is not contained in
an existing easement.) The flows then leave said swale and are conveyed in the low area
between the existing storage units and the railroad, and outfalls into the existing Sherwood
Lateral. With the re -development of portions of this site, the runoff directed to this outfall
point are limited to less than or equal to the existing release for both flow and volume.
The proposed re -development of portions of this site will not result in changes to the flows
and drainage structures on the east side of the this site, as the release rates will be limited to
' the existing 100-year release. (The basins were delineated and flows calculated for reference.)
(See below for further discussion.)
The runoff from the rear of the site (the existing outfall swale) has been calculated and the
developed flows will be limited to the existing 100-year runoff rate.
,1€Stll.;
AREA
AREA
C l 0
C 100-
Tc 10
Tc 100
Q 10
Q 100
DESIG.
ACRES
CFS
CFS
EX1
0.82
0.95
1.001
5.0
10.0
4.35
5.8
1
0.51
0.92
1.00
5.0
10.0
2.62
3.63
EX1,El
1.33
0.941
1.00
5.0
10.0
6.97
9.4
2
0.71
0.891
1.00
5.0
10.0
3.51
5.0
3
0.25
0.83
1.00
5.0
10.0
1.16
1.7
4
0.84
0.92
1.001
5.0
10.0
4.33
5.9
5
0.28
0.90
1.001
5.0
10.0
1.40
1.9
6
0.98
0.87
1.001
5.0
10.0
4.78
6.9
7
0.16
0.811.
1.00
5.0
10.0
0.72
L I
8
0.07
0.951
1.00
5.0
10.0
0.37
0.5
9
0.41
0.951
1.00
5.0
10.01
2.17
2.9
10
0.56
0.951
1.00
5.0
10.0
2.97
3.9
11
0.58
0.90
1.001
5.0
10.0
2.91
4.13
12
0.29
0.95
1.00
5.0
10.0
1.54
2.0
13
0.74
0.93
1.00
5.0
10.0
3.84
5.2
14
0.64
0.87
1.00
5.0
10.0
3.10
4.5
15
1 0.4710.741
0.93
9.1
10.0
1.61
3.11
3
PUD, including consideration of all on -site and tributary off -site runoff.
1.5 Design Criteria
This report was prepared to meet or exceed the submittal requirements established in the City
ofFort .Collins' "Storm Drainage Design Criteria and Construction Standards" (SDDCCS),
dated May 1984. Runoff computations were prepared for the 10-year minor and 100-year
major storm frequency utilizing the rational method.
Where applicable, the criteria established in the "Urban Storm Drainage Criteria Manual"
(UDFCD), 1984, developed by the Denver Regional Council of Governments, has been
utilized.
' 1.6 Master Drainage Basin
LThis site falls within the Spring Creek Major Drainage Basin and a report entitled "Spring
Creek Master Drainageway Plan"was prepared by Engineering Professionals, Inc. in March
' 1988. This report provides a detailed storm drainage planning analysis for Spring Creek
through the City of Fort Collins, but the University Mall Redevelopment will not have an
r impact on the Spring Creek Major Drainage Basin.
' 2. HISTORIC (EXISTING) DRAINAGE
' The historic flows for this site looked at with respect to the proposed development consist
of the currently existing drainage patterns.
In general, the existing drainage patterns for this site consist of the routing of flows to existing
' area inlets in the following areas: the east parking area of this site; the loading ramps at the
rear of King Soopers; the existing businesses on the north and south; and the existing dirt
area in the southwest comer of this site.
The drainage from the westerly portion of this site is conveyed northerly along the westerly
' edge of the existing asphalt parking area to an existing swale. Said swale, which starts at the
northwest comer of subject site within the existing railroad right-of-way, is defined along the
2
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1. INTRODUCTION
1.1 Project Location
University Center PUD is the proposed re -development of portions of the University Mall.
This project is located in the Southeast One -Quarter of Section 23, Township 7 North, Range
69 West of the Sixth Principal Meridian, in the City of Fort Collins, Larimer County,
Colorado. (See FIGURE 1 - VICINITY MAP.)
This project is bounded on the south by existing commercial development (McDonalds and
the K-Mart Plaza Expansion, on the west by the Burlington Northern Railroad, on the north
by Montgomery Wards, and on the east by College Avenue. More specifically, this site can
be found on the west side of College Avenue, north and south of Columbia Road.
1.2 Site Characteristics
The general topography of this site consists primarily of existing asphalt parking lot, buildings,
' and curb, gutter and sidewalk. The southwest corner and westerly portion of the site consists
of poorly to very poorly covered range type land. The slopes range from 0.5 to 3 percent.
1 1.3 Soils
The soils for this site are comprised of the Nunn clay loams (73,74). (See FIGURE 2 - SOIL
MAP.)
The Nunn clay loams complex consists of nearly level soils on high terraces and fans.
Pertinent characteristics of this soil include slow to medium runoff and a slight to moderate
hazard of wind and water erosion. Nunn clay loams are categorized in Hydrologic Group C.
The source for soil data is the "Soil Survey for Larimer County Area, Colorado", prepared
by the United States Department of Agriculture Soil Conservation Service.
1.4 Purpose and Scope of Report
This report defines the proposed final drainage and erosion control plan for University Center
II
5.8 Permanent Stabilization ..........................................
16
6. MISCELLANEOUS ..................................................16
6.1 Variances .....................................................16
6.2 Irrigation Ditches ...............................................
17
6.3 Ditch Company Approval .........................................
17
6.4 Maintenance Agreements .........................................
17
7. REFERENCES ......................................................17
APPENDIX A - MAPS AND FIGURES
APPENDIX B - HYDROLOGIC CALCULATIONS
APPENDIX C - HYDROLOGIC CALCULATIONS
APPENDIX D - DETENTION CALCULATIONS
APPENDIX E - DETENTION CALCULATIONS
APPENDIX F - EROSION CONTROL
iii
TABLE OF CONTENTS
PAGE
CERTIFICATIONS......................................................... i
TABLE OF CONTENTS ..................................................... ii
INTRODUCTION.....................................................I
1.1 Project Location .................................................
1
1.2 Site Characteristics...............................................
1
1.3 Soils..........................................................1
1.4 Purpose and Scope of Report .......................................
1
1.5 Design Criteria ..................................................
2
1.6 Master Drainage Basin ............................................
2
2. HISTORIC (EXISTING) DRAINAGE ..................................... 2
3. DEVELOPED FLOWS .................................................
4
3.1
Method.......................................................4
3.2
Exterior Flows..................................................5
3.3
Onsite Flows ...................................................
5
3.4
General Flow Routing ............................................
5
3.5
Proposed Drainage Plan ...........................................
5
3.6
Hydrologic Analysis of the Proposed Drainage Conditions .................
7
3.7
Allowable Street Flow Capacities ....................................
9
3.8
Inlet Design ....................................................
9
3.9
Storm Sewer Design ............................................
10
4. DETENTION PONDS (PARKING AREA) .................................
10
4.1
West Parking Detention Area ...............:......................
11
4.2
Southwest Parking Detention Area .................................
12
4.3
South Parking Detention Area .....................................
13
4.4
Flow Rates Released to College Avenue Outfall System ..................
13
5. EROSION CONTROL ................................................
14
5.1
Introduction...................................................14
5.2
General Description .............................................
14
5.3
Soil Description ................................................
15
5.4
Erosion And Sediment Control Measures .............................
15
5.5
Dust Abatement................................................15
5.6
Tracking Mud on City Streets ......................................
16
5.7
Maintenance...................................................16
ii
i
CERTIFICATIONS
OWNER
' ZTI Group hereby certifies that the drainage facilities for University Center PUD shall be constructed
according to the design presented in this report. I understand that the City of Fort Collins does not
and will not assume liability for the drainage facilities designed and/or certified by my engineer. I
' understand that the City of Fort Collins reviews drainage plans pursuant to Colorado Revised Statutes
Title 30, Article 28; but cannot, on behalf of ZTI Group, guarantee that final drainage design review
will absolve University Center PUD and/or their successors and/or assigns of future liability for
improper design. I finther understand that approval of the Final Plat and/or Final Development Plan
does not imply approval of my Engineer's drainage design.
ZTI Group
ENGINEER
I hereby certify that this report for the Final Drainage and Erosion Control Report for University
Center PUD was prepared by me or under my direct supervision in accordance with the provisions
of the City of Fort Collins STORM DRAINAGE DESIGN CRITERIA and CONSTRUCTION
STANDARDS for the owners thereof. I understand that the City of Fort Collins does not and will
not assume liability for drainage facilities designed by others.
Respectfully Submitted,
David W. Klockeman, P.E.
Colorado Professional Engineer No. 29110
For and On Behalf of JR Engineering, Ltd.
II
JREngineering, Ltd.
4812 South College Avenue
Fort Collins, Colorado 80525
(970) 282-4335 • FAX (970) 282-4340
May 20, 1996
Mr. Basil Hamdan
City of Fort Collins
Stormwater Utility
235 Mathews Street
Fort Collins, Colorado 80524
Re: Final Drainage and Erosion Control Report
University Town Center PUD
Fort Collins, Colorado
Dear Basil:
4935 North 30th Street
Colorado Springs, Colorado 80919
(719) 593-2593 • FAX (719) 528-6613
6110 Greenwood Plaza Blvd.
Englewood, Colorado 80111
(303) 740-9393 • FAX (303) 721-9019
JR Engineering, IAd. (JR) is pleased to submit the attached. Final Drainage and Erosion Control
Report for University Town. Center PUD for your review and.approval. This report includes
information from the "Preliminary Drainage and Erosion Control Report - University Center PUD"
prepared by JR, Revised March 11, 1996. The hydraulic and hydrologic evaluation of the site was
performed in accordance with the specifications set forth in the City of Fort Collins' "Storm
Drainage Design and Criteria Manual".
If you have any questions regarding the procedures, methodology, or results presented herein, please
do not hesitate to contact me at your convenience.
Sincerely,
JR Engineering, Ltd.
David W. Klockeman, P.E.
Project Manager
Attachment
01
dcJ
Recycled
FINAL DRAINAGE AND
EROSION CONTROL REPORT
UNIVERSITY CENTER PUD
Prepared for:
ZTI GROUP
1220 SOUTH COLLEGE AVENUE
FORT COLLINS, COLORADO 80524
Prepared by:
JR ENGINEERING, LTD.
4812 South College Avenue
Fort Collins, Colorado 80525
(970) 282-4335
May 20, 1996
Job Number 9059.00