HomeMy WebLinkAboutRFP - 7394 N COLLEGE IMPROVEMENTS PROJECT - CONIFER TO WILLOX (2)ADDENDUM No. 1
SPECIFICATIONS AND CONTRACT DOCUMENTS
Description of BID 7394: N College Improvements Project - Conifer to Willox
OPENING DATE: 3:00 PM (Our Clock) June 6, 202012
To all prospective bidders under the specifications and contract documents described
above, the following changes/additions are hereby made and detailed as follows:
1. Revisions to the RFP:
Please replace the first sentence at the top of Page 13 with the following:
All applicable documents as determined during the NEPA process shall be
prepared in CDOT format and shall be presented to CDOT for review and
submittal to the FHWA.
2. Pre-Proposal Clarifications:
A. Can the final drainage report for the North College Improvements Project –
Vine to Conifer be made available as part of this Request for Proposals?
Please reference the City of Fort Collins website for the Final Drainage
Report for the North College Improvements Project – Vine to Conifer.
B. Do the water quality ponds currently being constructed as part of the North
College Improvements Project – Vine to Conifer have capacity for flows from
the planned project?
During the design phase of the North College Improvements Project – Vine to
Conifer, a stormsewer system and water quality ponds were designed that
could accommodate the project flows along with additional capacity for offsite
flows. Flows from the section of North College between Conifer Street and
Willox Lane were considered at a conceptual level resulting in additional
capacity for the stormsystem and water quality ponds. A detailed drainage
analysis should be included within your proposed scope to confirm
conclusions of the conceptual level evaluation. Per this detailed analysis, the
new stormsystem, along with any water quality elements, will need to be
designed appropriately and in accordance with City and CDOT design criteria.
Financial Services
Purchasing Division
215 N. Mason St. 2nd Floor
PO Box 580
Fort Collins, CO 80522
970.221.6775
970.221.6707
fcgov.com/purchasing
3. Additional Information
Exhibit 1 – Drainage & Erosion Control Report
Please contact John Stephen, CPPO, LEED AP, Senior Buyer at (970) 221-6777 with
any questions regarding this addendum.
RECEIPT OF THIS ADDENDUM MUST BE ACKNOWLEDGED BY A WRITTEN
STATEMENT ENCLOSED WITH THE BID/QUOTE STATING THAT THIS ADDENDUM
HAS BEEN RECEIVED.
NORTH COLLEGE IMPROVEMENTS
PROJECT – PHASE II
Vine Drive to Conifer/Hickory Intersections
Drainage and Erosion Control Report
Prepared for
City of Fort Collins
250 North Mason Street
Fort Collins, Colorado 80522
EXHIBIT 1
NORTH COLLEGE IMPROVEMENTS
PROJECT – PHASE II
Vine Drive to Conifer/Hickory Intersections
Drainage and Erosion Control Report
Prepared for
City of Fort Collins
250 North Mason Street
Fort Collins, Colorado 80522
P.O. Box 270460
Fort Collins, Colorado 80527
(970) 223-5556, FAX (970) 223-5578
Ayres Project No. 32-1415.02
NC-VINE7.DOC
July 2010
i Ayres Associates
TABLE OF CONTENTS
1. Introduction .................................................................................................................. 1.1
1.1 Project Description and Location .......................................................................... 1.1
1.2 Land Use............................................................................................................... 1.3
1.3 Local Drainage Ways............................................................................................ 1.4
1.4 Existing Street Layout ........................................................................................... 1.4
1.5 Proposed Street Layout ........................................................................................ 1.4
2. Existing Drainage Systems .......................................................................................... 2.1
2.1 Existing Drainage Concept ................................................................................... 2.1
2.1.1 West Side of North College Avenue .............................................................. 2.1
2.1.2 East Side of North College Avenue ............................................................... 2.1
2.2 Storm Sewer Criteria and Constraints .................................................................. 2.5
3. Hydrology..................................................................................................................... 3.1
3.1 Rainfall.................................................................................................................. 3.1
3.2 Drainage Basin Parameters.................................................................................. 3.1
3.3 Existing Drainage Basins...................................................................................... 3.3
3.3.1 West Side of North College Avenue .............................................................. 3.3
3.3.2 East Side of North College Avenue ............................................................... 3.4
3.3.3 Existing Flow Summary ................................................................................. 3.4
3.4 Proposed Drainage Basins ................................................................................... 3.5
3.4.1 West Side of North College Avenue .............................................................. 3.9
3.4.2 East Side of North College Avenue ............................................................... 3.9
3.4.3 Proposed Flow Summary .............................................................................. 3.9
4. Hydraulic Design.......................................................................................................... 4.1
4.1 Proposed Storm Sewer General Design Concept ................................................ 4.1
4.2 Proposed Storm Sewer System............................................................................ 4.1
4.3 Inlet Sizing ............................................................................................................ 4.2
4.4 Water Quality Pond Analysis ................................................................................ 4.3
4.5 Siphon Under Lake Canal..................................................................................... 4.5
4.6 Josh Aimes/Lake Canal Flows.............................................................................. 4.5
4.7 Existing System Near Vine Drive.......................................................................... 4.6
4.8 Utilities .................................................................................................................. 4.6
4.9 Master Plan Drainage (NCDID and NECCO) ....................................................... 4.9
5. Poudre River Floodplain and Floodway ....................................................................... 5.1
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6. Pedestrian Bridge ........................................................................................................ 6.1
6.1 Location ................................................................................................................ 6.1
6.2 Hydrology.............................................................................................................. 6.1
6.3 Existing Conditions Model..................................................................................... 6.2
6.4 Modeling Approach and Assumptions .................................................................. 6.2
6.5 Rise in Water Surface Elevation ........................................................................... 6.2
6.6 Freeboard ............................................................................................................. 6.4
6.7 Preventing Failure Due to Scour........................................................................... 6.4
6.7.1 Contraction Scour.......................................................................................... 6.5
6.7.2 Abutment Scour............................................................................................. 6.5
6.8 Scour Results........................................................................................................ 6.5
7. Erosion Control ............................................................................................................ 7.1
7.1 Existing Soil Data.................................................................................................. 7.1
7.2 Existing Vegetation, Including Percent Cover....................................................... 7.1
7.3 Temporary Sediment/Erosion Control Methods.................................................... 7.1
7.4 Sediment/Erosion Control Methods ...................................................................... 7.2
7.5 Materials Handling and Spill Prevention ............................................................... 7.5
7.6 Inspection and Maintenance................................................................................. 7.6
8. References................................................................................................................... 8.1
APPENDIX A – Street Capacity Calculations.........................................................................--
APPENDIX B – Existing Drainage..........................................................................................--
APPENDIX C – Proposed Drainage.......................................................................................--
APPENDIX D – Existing Utilities ............................................................................................--
APPENDIX E – Pedestrian Bridge Analysis...........................................................................--
APPENDIX F – Erosion Control .............................................................................................--
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LIST OF FIGURES
Figure 1.1. Vicinity Map...................................................................................................... 1.2
Figure 1.2. Typical cross section of proposed North College Avenue................................ 1.5
Figure 3.1. Proposed drainage basins. .............................................................................. 3.6
Figure 4.1. North College Avenue Improvements Overall Storm Plan. .............................. 4.2
Figure 5.1. Floodplain Exhibit............................................................................................. 5.2
Figure 6.1. HEC-RAS Cross Section Layout...................................................................... 6.3
Figure 6.2. Freeboard for bridge on continuous grade (CDOT 2004). ............................... 6.4
LIST OF TABLES
Table 2.1. CDOT and COFC Criteria. ................................................................................ 2.5
Table 3.1. Street Capacity vs. Existing Stormwater Flows................................................. 3.1
Table 3.2. Total Rainfall Depths......................................................................................... 3.1
Table 3.3. City of Fort Collins Hyetographs........................................................................ 3.2
Table 3.4. Existing Flow Summary..................................................................................... 3.5
Table 3.5. Proposed Basin Flows. ................................................................................... 3.10
Table 4.1. Values for Exit and Entrance Losses. ............................................................... 4.3
Table 4.2. Values for Entrance Losses. ............................................................................. 4.3
Table 4.3. Inlet Summary. .................................................................................................. 4.4
Table 4.4. Water Quality Pond Summary........................................................................... 4.5
Table 4.5. Existing System Near Vine Drive Capacity During 100-Year Event.................. 4.7
Table 4.6. Existing Utility Information................................................................................. 4.7
Table 6.1. Pedestrian Bridge Hydrology............................................................................. 6.1
Table 6.2. Effects of Pedestrian Bridge.............................................................................. 6.2
Table 6.3. Freeboard Summary. ........................................................................................ 6.4
1.1 Ayres Associates
1. INTRODUCTION
1.1 Project Description and Location
North College Avenue, also US Highway 287 and Colorado State Highway 14 (north of
Jefferson Street), is a major north-south route through the City of Fort Collins which provides
the northern entryway into the City. The arterial provides both local and regional connectivity
and carries a large volume of interstate truck traffic. Over time, citizens have expressed
concern about the corridor's physical condition, as well as associated challenges to
economic prosperity. Through previous planning efforts, the City identified needs to create a
gateway into the City, to improve mobility for the traveling public, including bicyclists and
pedestrians, and to establish a strong connection to downtown and the Poudre River.
In 2005, Fort Collins voters approved the Building on Basics (BOB) 1/4 cent sales tax to fund
capital projects, including improvements on the North College Avenue between Vine Drive
and Conifer Street. In addition, the City has secured State and Federal funding for
construction of improvements between Vine Drive and the Conifer/Hickory intersections.
Project costs are anticipated to exceed appropriated funds.
The project area encompasses approximately 1/2 mile of North College Avenue between
Vine Drive and Hickory Street. The roadway is a four-lane, urban highway with a two-way
left turn lane throughout most of the corridor. The highway is generally shouldered with
open, uncontrolled access, and limited storm drainage facilities. Corridor users include
automobiles, heavy truck traffic, bicyclists, and pedestrians. Designated facilities for
bicyclists and pedestrians are not continuously available. In general, land use along the
project corridor is commercial and light industrial. Partial right-of-way acquisition of multiple
properties is anticipated as part of the project due to additional width needed for proposed
improvements. A portion of the project lies within the Poudre River floodway. Construction
of improvements in the floodway is limited for public safety reasons.
As stated previously, College Avenue is a major north-south arterial route through the City of
Fort Collins. It provides the northern entryway into the City and is a primary route to access
downtown. Currently, one transit route utilizes North College Avenue in the southbound
direction. The City plans to expand transit service in the area, utilizing North College Avenue
south of Conifer Street as an enhanced travel corridor for the area north of downtown. Also,
functioning as US Highway 287 (US 287) and Colorado State Highway 14 (SH 14) (north of
Jefferson Street), North College Avenue provides both local and regional connectivity linking
Colorado and Wyoming, as well as providing a link to Interstate 25 via SH 14. Designated as
the Cache La Poudre - North Park Scenic Byways route, North College Avenue is a gateway
to the mountains and to recreational lands in northwestern Colorado and Wyoming
(see Figure 1.1 for a vicinity map of the project area).
According to the City of Fort Collins website, www.fcgov.com, the North College
Improvements Project is located in the City of Fort Collins Dry Creek Basins. Dry Creek is a
tributary of the Cache la Poudre River. The Dry Creek basin, which begins near the
Wyoming border, has a drainage area of about 62 square miles with a series of irrigation
canals and reservoirs dominating the upper basin. Due to agriculture and development, only
a fraction of the original drainage channel remains. Dry Creek enters Fort Collins near Willox
Lane and College Avenue and meanders through small remnants of ditches and channels
until it joins the Cache la Poudre River near Mulberry Street and Timberline Road.
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Figure 1.1. Vicinity Map.
1.3 Ayres Associates
Although local newspapers reported numerous floods over the last 100 years that affected
different areas in and around Fort Collins, many floods in Dry Creek probably went unnoticed
due to the sparse population in the upper basin. A local resident documented that in 1924
there was flooding that was "belly deep to a horse" in the area that is now JAX Surplus.
In the flood in August 1951, the Coloradoan reported two breaks in the Eaton Ditch (Larimer
and Weld Canal) which spilled over into Dry Creek and "flooded tourist camps, stores and
houses on the west side of N. College Avenue north of the City limits." In the same storm,
another 20 houses flooded in the Goering Addition, west of the old speedway track at the
northwest corner of Willox Lane and College Avenue. In 1977, another storm brought 4.28
inches of rain in 24 hours, flooding basements north of town, most likely in the Dry Creek
basin.
In spite of the small number of reported floods in the Dry Creek basin, it contains a very large
drainage area - significant flooding could occur at any time.
The proposed project is also within the Poudre River floodplain. According to the City of Fort
Collins website, www.fcgov.com, the location of the City of Fort Collins is where it is today
because of flooding on the Poudre River. The first military post, Camp Collins, was originally
established near the present day town of LaPorte. It was destroyed in 1864 when the
Poudre River flooded. Camp Collins was relocated to higher ground near present day Old
Town in Fort Collins.
There are several well-documented large floods on the Poudre River around the turn of the
century. A flood in 1891 was due to a dam break on Chambers Lake. The most notable
flood was in 1904. This storm was greater than a 100-year event and resulted in the death of
Fort Collins resident Robert Strauss. The Buckingham, Alta Vista, and Andersonville
neighborhoods were severely damaged by the 1904 flood. The most recent flood on the
Poudre River was a relatively small one in the spring of 1999. It was caused by rain and
snow runoff during a warm period in April. The flood lasted only a few days, but resulted in a
great deal of bank erosion and threatened many properties. The Poudre River behind the
Mulberry Water Reclamation Facility had flows of almost 4,000 cubic feet per second (cfs).
Normal river flow at this location is 100 cfs.
Although the Poudre River has not flooded in recent years, we know from the past that large
floods on the Poudre River can happen. Only the future will tell how flooding on the Poudre
River could change the history of Fort Collins again.
1.2 Land Use
In general, land use along the project corridor is commercial and light industrial with several
auto-related businesses. The adjacent properties are predominantly small and individually
owned. This situation creates potential opportunity for redevelopment to occur in the short-
term. A majority of the area is zoned Service Commercial District with a small segment near
the south end of the corridor zoned Community Commercial – Poudre River District.
Redevelopment in the area is anticipated as largely commercial and mixed-use. At the
southern end of the project, just north of the Poudre River is a small piece of land that is
currently undeveloped land in the floodway. This land will be used for a water quality pond.
1.4 Ayres Associates
1.3 Local Drainage Ways
The local drainage ways of the area include the Poudre River, Lake Canal, and Josh Aimes
Ditch. North College Avenue crosses over the Poudre River and Lake Canal, just south and
north of Vine Drive, respectively. The 500-year Poudre River floodplain extends to a location
between Lake Canal and Alpine Street along North College Avenue and as far north as
Pinon Street for adjacent properties. The 1/2-foot Poudre River floodway ends
approximately 100-150 ft south of Lake Canal, influencing the types of project improvements
that can be implemented south of the canal.
1.4 Existing Street Layout
The horizontal alignment of North College Avenue is straight, generally following the section
line from Vine Drive to Conifer Street. The profile of the roadway is nearly flat and slopes
south toward the Poudre River. A normal (2%) cross-slope generally exists. The street
slopes range from 0.14% to 0.8%.
1.5 Proposed Street Layout
The proposed design includes the following:
12 ft through lane width (exclusive of the curb and gutter)
11 ft auxiliary lane width (exclusive of the curb and gutter)
15 ft raised, landscaped median – 4 ft median with 11 ft left turn lane
8 ft detached shared use path
7.5 ft landscape buffer (inclusive of 0.5 ft curb head)
6 ft on-street bike lane (inclusive of 2 ft gutter)
110 ft ROW width
Gateway Entry between Poudre River and Lake Canal compatible with floodway
requirements
Pedestrian bridge crossings at Lake Canal
Figure 1.2 is a typical cross sectional view of the proposed North College Avenue.
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Figure 1.2. Typical cross section of proposed North College Avenue.
2.1 Ayres Associates
2. EXISTING DRAINAGE SYSTEMS
2.1 Existing Drainage Concept
The high center line of North College Avenue creates a natural drainage divide between the
east and west sides of North College Avenue. Due to the high centerline, the existing
drainage patterns along North College Avenue can be broken out into the west side of
College and the east side of College.
2.1.1 West Side of North College Avenue
The west side of North College Avenue generally slopes from north to south. The drainage
area for the west half of North College Avenue is bound by the Larimer and Weld to the north
and by the Lake Canal to the south. The drainage area is bound by the railroad tracks to the
west and North College Avenue to the east. Approximately 100 to 200 feet west of North
College Avenue is a low spot that travels the length of the drainage area. This low spot acts
as the main drainage path for the west half of College. The drainage path collects flows from
the adjacent developments. The majority of the adjacent developments along the west half
of College do not detain the storm runoff from their developments.
Currently, there are two storm sewer systems along the west side of North College Avenue.
One system starts at the intersection of Willox Street and North College Avenue. The storm
sewer runs along the west side of College and consists of roadside ditches and small
diameter storm sewer. The storm sewer crosses under North College Avenue at the
intersection of Hickory and North College Avenue and runs east where it ultimately outlets
into Dry Creek.
A second storm sewer system starts south of the intersection of Hickory and North College
Avenue. This system runs south along the west side of North College Avenue with inlets and
laterals picking up local stormwater from North College Avenue, surrounding side streets and
adjacent development. This system runs south and discharges into the Josh Aimes Ditch
which ultimately discharges into the Lake Canal irrigation ditch.
Both existing storm sewer systems are undersized, are filled with sediment and debris, and
do not meet either the City of Fort Collins or CDOT stormwater criteria for encroachment
(spread) or allowable depth of ponding (see Section 2.2 for storm criteria). Figure 2.1
depicts the existing drainage basins for the project area.
2.1.2 East Side of North College Avenue
The east side of North College Avenue generally slopes from west to east. Because there is
no curb and gutter along North College Avenue the stormwater discharges off of North
College Avenue and onto the adjacent properties. Ultimately the majority of the runoff from
the east half of North College Avenue is collected in Dry Creek or the Lake Canal irrigation
ditch. With the improvements to North College Avenue and the addition of curb and gutter
the storm runoff can not continue to discharge onto the adjacent properties. An adequately
sized storm sewer system in combination with the street capacity must be designed to meet
both the City of Fort Collins and CDOT criteria for encroachment and depth of ponding (see
Section 2.2 for storm criteria). Exhibit 2.1 depicts the existing drainage basins for the project
area.
2.5 Ayres Associates
2.2 Storm Sewer Criteria and Constraints
Table 2.1 lists storm drainage design criteria for both CDOT and the City of Fort Collins.
Table 2.1. CDOT and COFC Criteria.
Agency 10-year 100-year
Spread FL Depth Spread FL Depth CL Depth
COFC Leave one
lane free of
water
6 in
Leave one
lane free of
water
6 in None
CDOT Shoulder +3ft --- --- 18 in 6 in
3.1 Ayres Associates
3. HYDROLOGY
Based on CDOT and the City of Fort Collins storm drainage criteria the capacity of North
College Avenue ranges from approximately 0.5 to 2 cfs for the 10-year event and
approximately 34 to 140 cfs for the 100-year event. The capacity is based on the street
cross slope and gutter slope. Table 3.1 compares the existing capacity of North College
Avenue to the accumulated storm runoff at the downstream end of the project area for the
west and east sides of North College Avenue.
Table 3.1. Street Capacity vs. Existing Stormwater Flows
for North College Avenue.
10-year 100-year
Street Capacity 0.5-2 cfs 34-140 cfs
Total Cumulated Flow +/- 45 cfs +/- 70 cfs
While the 100-year flow does not exceed the current street capacity for the majority of the
project site, the 10-year flow greatly exceeds the current street capacity. Therefore, the
controlling flow for the design of the storm drainage system is the 10-year event (refer to
Appendix A for Street Capacity Calculations).
3.1 Rainfall
The standard 2-hour rainfall hyetographs used throughout the City of Fort Collins were used
for the hydrologic modeling efforts. These hyetographs can be found in the City of Fort
Collins Drainage Criteria Manual. The system was designed to meet both the major (100-
year) and minor (10-year) events. Table 3.2 is a summary of the total rainfall depths
associated with each of the three return period storms. Table 3.3 gives the actual rainfall
hyetographs defined for the three storm events.
Table 3.2. Total Rainfall Depths.
Rainfall Period 2-year 10-year 100-year
Rainfall Depth (in) 0.98 1.71 3.67
3.2 Drainage Basin Parameters
Drainage basins were delineated for both the east and west sides of North College Avenue.
Offsite basins were delineated along the west side of North College Avenue to account for
the offsite flows that contribute to the existing storm sewer system. The following parameters
were determined for each of the delineated basins:
Basin Area: Current runoff patterns and development conditions within the project site were
defined beginning with a detailed sub basin evaluation and delineation. The basins along
North College Avenue were delineated using surveyed topographic information that was
obtained for this project. Offsite basins were delineated using 1-foot aerial topographic
information that was obtained with the North College Drainage Improvements Design
(NCDID) project.
3.2 Ayres Associates
Table 3.3. City of Fort Collins Hyetographs.
Time (min) 2-year 10-year 100-year
5 0.29 0.49 1.00
10 0.33 0.56 1.14
15 0.38 0.65 1.33
20 0.64 1.09 2.23
25 0.81 1.39 2.84
30 1.57 2.69 5.49
35 2.85 4.87 9.95
40 1.18 2.02 4.12
45 0.71 1.21 2.48
50 0.42 0.71 1.46
55 0.35 0.60 1.22
60 0.30 0.52 1.06
65 0.20 0.39 1.00
70 0.19 0.37 0.95
75 0.18 0.35 0.91
80 0.17 0.34 0.87
85 0.17 0.32 0.84
90 0.16 0.31 0.81
95 0.15 0.30 0.78
100 0.15 0.29 0.75
105 0.14 0.28 0.73
110 0.14 0.27 0.71
115 0.13 0.26 0.69
120 0.13 0.25 0.67
Basin Width: The basin width was computed by dividing the overland flow length into the
basin area. The overland flow length was estimated for each basin by averaging the
distances associated with several representative flow paths as defined using the topographic
mapping.
Percent Impervious: The percentage of area within each basin that was impervious was
estimated based on recent aerial photography. The aerial photography was verified with field
visits.
Basin Slope: The basin slope was estimated based on the topographic information that was
available for this project.
Additional Parameters: Additional parameters, including overland roughness values,
surface storage, and infiltration rates were defined using standard values currently specified
by the City of Fort Collins Utilities.
Overland roughness coefficient (impervious areas): 0.016
Overland roughness coefficient (pervious areas): 0.250
Surface storage (impervious area): 0.1 inches
Surface storage (pervious area): 0.3 inches
Initial Infiltration Rate: 0.51 in/hr
Final infiltration rate: 0.50 in/hr
Decay rate coefficient: 0.0018 sec-1
3.3 Ayres Associates
Once the above parameters were obtained, EPA SWMM version 5.0.0018 was used to
determine the 10- and 100-year flows. During the design phase, inlets were added and the
corresponding basins were adjusted to insure that the 10-year street capacity was not
exceeded (refer to Section 3.0 for North College Avenue street capacity and COFC and
CDOT requirements).
3.3 Existing Drainage Basins
There are 24 existing drainage basins. Basins EX1 through EX12 are offsite basins that
drain to the existing storm sewer system or the main drainage path along North College
Avenue. Basins EX13 through EX20 make up the west half of North College Avenue while
basins EX21 through EX24 make up the east half of North College Avenue. Basins S1
through S4 were created to verify the capacity of the existing storm sewer near Vine Drive
(refer to Appendix B for Existing Drainage Basin Calculations).
3.3.1 West Side of North College Avenue
The majority of the drainage along the west half of North College Avenue drains to a low spot
that is approximately 100 to 200 ft west of North College Avenue. This low spot acts as the
main drainage path for the west half of North College Avenue. The drainage path begins
south of Willox and continues south to the Josh Aimes Ditch and Lake Canal.
Drainage along the west side of North College Avenue starts with basin EX12, north of
Willox. The basin is currently developed (residential and commercial) and flows to a low spot
on Willox. The storm flows overtop Willox and continue south, via overland flow, ultimately to
the low spot in Hickory.
Basins EX11, EX9, EX6, and EX4 also drain to the low spot in Hickory via overland flow.
The basins consist of a mix between undeveloped land, commercial development, residential
subdivisions, and a mobile home park.
Basins EX8 and EX7, commercial developments, drain south to the existing storm sewer
system along North College Avenue. The storm sewer system consists of small diameter
storm sewer and roadside drainage ditches. The existing storm sewer system starts south of
Willox and continues to the Hickory and North College Avenue intersection. At this
intersection the storm sewer crosses under North College Avenue and discharged in Dry
Creek. This system is undersized and filled with sediment and debris. When the capacity of
the storm sewer system is exceeded, the storm runoff overflows to the low spot in Hickory.
Basin EX10 is a subdivision that drains to Dry Creek. Basin EX5 is Dry Creek. Dry Creek
drains to an existing 30" clogged storm sewer which connects into the storm sewer system
along North College Avenue. The flows from Dry Creek overtop and flow south to the low
spot in Hickory.
The Hickory low spot, design point DP1, is approximately 3 ft lower than the intersection of
North College Avenue and Hickory and is drained by an existing storm sewer. The existing
storm sewer connects into the existing storm sewer system along North College Avenue.
Once the storm sewer capacity has been met, the storm flows overtop Hickory and travel
south continuing in the main drainage path along the west side of North College Avenue.
3.4 Ayres Associates
The overtopping flows, along with runoff from basins EX2 and EX3, travel south in the main
flow path to a low spot at Hemlock, design point DP2. These basins are a combination of
undeveloped land and commercial development. The low spot at Hemlock is drained by a
small storm sewer which connects into an existing storm sewer system in North College
Avenue. This existing system starts just north of Hemlock and continues south where it
discharges into the Josh Aimes Ditch. The Josh Aimes ditch crosses under North College
Avenue and outlets into Lake Canal. Once the storm sewer capacity is met, the flows
overtop Hemlock and head south.
The flows overtopping Hemlock, along with the runoff from basin EX1, drain into the Josh
Aimes Ditch, design point DP3, via overland flow. Basin EX1 mainly consists of residential
development.
Josh Aimes ditch travels under North College Avenue in a 2x6 RCBC. Once across North
College Avenue the storm sewer is connected into an 30" RCP. The 30" RCP outlets into
the Lake Canal. The 30" RCP has capacity of approximately 30 cfs. During a 100-year
event there is approximately 265 cfs that drains to the Josh Aimes ditch, DP3. According to
existing contours and weir calculations, the flow will overtop Josh Aimes ditch and head
south to the Lake Canal and east to North College Avenue. The majority of the flows that get
to North College Avenue will flow back to the west and ultimately back into the Lake Canal.
A portion of the flows will cross over North College Avenue and into the Lake Canal.
Basins EX14 to EX20 consist of the west half of North College Avenue along with the
commercial developments that drain directly onto North College Avenue. These basins drain
to the existing storm sewer system along North College Avenue. Once capacity of the
existing storm sewer is met, the storm flows will overtop the storm sewer and travel south
along North College Avenue to the Josh Aimes ditch and the Lake Canal.
3.3.2 East Side of North College Avenue
The east side of North College Avenue generally slopes from west to east. Because there is
no curb and gutter along North College Avenue the stormwater discharges off of North
College Avenue and onto the adjacent properties. Ultimately the majority of the runoff from
the east half of North College Avenue is collected in Dry Creek or the Lake Canal irrigation
ditch. Basins EX21 to EX24 consist of the east half of North College Avenue. These basins
drain directly offsite to the surrounding developments.
Basins S1 to S4 consist of North College Avenue. These basins drain to an existing storm
sewer system near the proposed water quality ponds. The existing system discharges into
the Poudre River, design point DP4. These basins were created to verify the capacity of the
existing storm sewer.
3.3.3 Existing Flow Summary
Table 3.4 summarizes the existing basin flows for this project.
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Table 3.4. Existing Flow Summary
Basin/Design Point 10-year Flow (cfs) 100-year Flow (cfs)
West Side
EX01 37.53 91.98
EX02 43.78 108.17
EX03 11.69 33.51
EX04 97.83 252.10
EX05 5.23 25.71
EX06 14.88 39.34
EX07 6.29 13.28
EX08 20.02 42.30
EX09 74.64 189.82
EX10 37.28 82.27
EX11 32.04 85.68
EX12 64.51 164.02
EX13 0.80 3.73
EX14 2.09 4.37
EX15 1.33 2.78
EX16 2.42 5.06
EX17 8.55 17.86
EX18 0.81 1.69
EX19 4.51 9.43
EX20 7.36 15.38
East Side
EX21 1.14 2.38
EX22 5.42 11.31
EX23 6.79 14.19
EX24 4.32 9.03
Southern Existing Basins
S1 --- 4.03
S2 --- 2.17
S3 --- 3.35
S4 --- 4.63
3.4 Proposed Drainage Basins
There are 48 proposed drainage basins. Basins OS1 through OS12 are offsite basins that
drain to the existing storm sewer system along North College Avenue. The proposed system
will pick up the existing storm sewer system. Basins W01 through W18 make up the west
half of North College Avenue while basins E01 through E13 make up the east half of North
College Avenue.
Figure 3.1 shows the proposed drainage basins (refer to Appendix C for Proposed
Drainage Calculations).
3.9 Ayres Associates
3.4.1 West Side of North College Avenue
The flow along the west half of North College Avenue continues along the same path as
described in the sections above. The offsite basins are the same as the existing basins; the
nomenclature has just been changed for the proposed basin discussion. The "EX" in front of
the existing basins was changed to "OS." For a detailed discussion in basins OS1 to OS12,
refer to the previous sections (referencing EX1 to EX12). The offsite basins were analyzed
because they contribute to the existing storm sewer system, and are accounted for in the
proposed storm sewer design.
The offsite basins flow to the Josh Aimes ditch, approximately 265 cfs. With the design of
the North College Avenue storm sewer system, the flow to the Josh Aimes ditch is not
reduced. The flow is controlled by the surrounding developments and not by the flow on
North College Avenue. With the project a low spot will be added in Woodlawn Drive and the
Lake Canal will be siphoned. The storm flows will overtop Woodlawn Drive and continue
south, over the Lake Canal siphon and to the water quality pond, design point DP5. The
flows will proceed through the water quality ponds where they will eventually spill into the
Poudre River through the spillway located at the south end of the pond.
Basins W1 to W18 consist of the west half of North College Avenue along with the
commercial developments that drain directly onto North College Avenue. These basins drain
to the proposed storm sewer system along North College Avenue and ultimately to the water
quality ponds, design point DP4. The basins were broken out in order to model each inlet.
3.4.2 East Side of North College Avenue
The east side of North College Avenue generally slopes from west to east. With the addition
of curb and gutter, the flows do not travel offsite as in existing conditions.
Basins E1 to E13 consist of the east half of North College Avenue. These basins drain to
the proposed storm sewer system along North College Avenue and ultimately to the water
quality ponds, design point DP5. Basins E2, E3, E10, E12, and E13 will continue to travel
offsite as in existing conditions. These basins are in areas where it is difficult to collect all
the site runoff. The offsite flows are reduced from existing conditions and do not adversely
affect the existing developments.
3.4.3 Proposed Flow Summary
Table 3.5 summarizes proposed basin flows for this project.
3.10 Ayres Associates
Table 3.5. Proposed Basin Flows.
Basin/Design Point 10-year Flow (cfs) 100-year Flow (cfs)
Off Site Basins
OS1 37.53 108.17
OS2 43.78 33.23
OS3 11.59 252.20
OS4 97.87 25.71
OS5 5.23 39.34
OS6 14.88 13.28
OS7 0.00 0.00
OS8 20.02 189.82
OS9 74.64 82.27
OS10 37.28 85.68
OS11 32.04 164.02
OS12 64.51 3.01
West Side
W01 1.37 1.27
W02 0.58 3.61
W03 1.64 1.37
W04 0.62 3.31
W05 1.51 5.87
W06 2.54 4.23
W07 1.84 4.60
W08 2.10 1.67
W09 0.79 5.20
W10 2.46 2.64
W11 1.21 5.03
W12 2.32 6.53
W13 3.03 5.96
W14 2.68 3.42
W18 0.00 0.00
East Side
E01 0.71 1.56
E02 0.58 1.27
E03 0.31 0.68
E04 1.78 3.91
E05 1.07 2.34
E06 2.36 5.18
E07 1.79 3.92
E08 1.31 2.85
E09 2.70 5.83
E10 3.24 7.01
E12 0.23 0.49
E13 37.53 91.98
4.1 Ayres Associates
4. HYDRAULIC DESIGN
4.1 Proposed Storm Sewer General Design Concept
A traditional storm sewer system is proposed to collect project stormwater flows. The design
includes a main trunk line on the west side of North College Avenue with laterals connecting
proposed inlets from the east and west side of North College Avenue. In addition, the
existing storm sewer along the west side of North College Avenue and at Hickory will be tied
into the new trunk line. Proposed inlets will be added where needed due to limited street
capacity. The inlets and storm sewer are sized to convey the 10-year event. Once
constructed, the system will meet City of Fort Collins and CDOT storm drainage criteria for
encroachment and depth of flow for both the 10- and 100-year events (see section 3 for
North College Avenue street capacity calculation results).
Storm flows will be treated in a water quality pond before discharge into the Poudre River.
Water quality ponds will be located between the Lake Canal and Poudre River on parcels
currently owned by the City of Fort Collins Stormwater Department. The Stormwater
Department has approved use of this property for purposes of water quality treatment. In
addition, the ponds will be incorporated into the proposed gateway as described in Section 5.
The Lake Canal will be siphoned under the proposed storm sewer. A siphon can not be
avoided due to the flowline elevation of the Lake Canal compared to the discharge location in
the Poudre River. Siphoning the storm sewer under the Lake Canal was analyzed, but after
a detailed investigation the COFC and CDOT preferred the Lake Canal siphon to the storm
sewer siphon. Further discussion on the siphon can be found in Section 4.5.
Figure 4.1 shows the proposed storm sewer system.
4.2 Proposed Storm Sewer System
In order to accurately size the proposed storm sewer system a hydraulic model of the project
was created. EPA SWMM version 5.0.0018 was used to analyze the proposed storm sewer
system including the proposed water quality pond and siphon. EPA SWMM was chosen
because of its ability to model various hydraulic flow regimes including backwater,
surcharging, reverse flow, and surface ponding.
EPA SWMM uses a series of links, nodes and ponds to represent the components of the
storm sewer system. Inlets were modeled with a node. The invert assigned to the inlet is the
proposed outlet pipe invert. The actual size of the inlet was determined using UDInlet. The
UDInlet calculations can be found in Appendix C.
The proposed storm sewer connects into the existing storm sewer system. In order to
account for the flows from the existing system, portions of the existing system were added to
the EPA SWMM model. The existing system overflows, thereby affecting downstream inlets.
This was modeled using overflow links and nodes at the existing inlets. The overflow link is
set at the grate flowline of the inlet. When the storm runoff exceeds the capacity of the
exiting pipe, the inlet overtops and travels downstream. Overflow links were also added for
the proposed inlets to model any overtopping that may occur during the 100-year event. No
overtopping of the proposed inlets occurs during the 10-year event.
NORTH COLLEGE AVENUE IMPROVEMENTS
OVERALL STORM PLAN
J. MICHAELSEN
J. MICHAELSEN
STORM EXHIBIT 4.1
1" = 60' 1" = 120'
W W W W W W W
W W W W W
W W W W W W W
W
W
W W
G G G G G
G G
G G
W
G G G G G G G G G G G G
G
G
G G
W W W
W W
W W W W W
W W
W W W W W W W W
W W W
W W W W W W W
W W W W W W W
W W
E E E
E E E E E
E E E
E E E E E E E
E
FO FO FO
FO FO
FO
FO
FO FO FO
FO FO FO
FO
FO
FO FO FO
FO FO FO
FO
FO FO FO FO FO FO FO
FO FO FO
FO FO
FO FO FO
FO
FO
FO
FO
FO FO
FO
FO FO FO FO
FO FO
FO
FO FO
FO
4.3 Ayres Associates
Exit and entrance losses were assigned to each pipe according to documentation from the
UDSewer program developed by Urban Drainage. Both EPA SWMM and UDSewer
calculate friction losses through the pipe and through the structures (i.e., manholes, inlets
etc.) with the same equations. Because EPA SWMM does not provide any documentation
on loss values, the values documented in UDSewer were used. Table 4.1 shows the values
used for exit and entrance losses.
Table 4.1. Values for Exit and Entrance Losses.
Angle in
Degree
Bend Loss Coefficient for
Curved Deflector Manhole
Bend Loss Coefficient for
Non-shaping Manhole
Straight Through 0.05 0.05
22.5 0.08 0.1
45 0.28 0.4
60 0.46 0.64
90 1.01 1.32
A Snout oil-water debris separator is to be installed on the manhole just upstream of the
water quality pond. The purpose of the Snout is to trap oil, sediment and trash within a
deepened inlet or manhole section until it can be removed with a vac truck by City of Fort
Collins maintenance personnel. The Snout is a relatively new water quality BMP. The Snout
will ultimately minimize the amount of oil, sediment and trash that would have otherwise
entered the water quality pond in the Gateway area.
Entrance losses for the manhole which will incorporate the snout is based on documentation
from the Snout manufacturer; Best Management Products, Inc. According to the
manufacturer, the losses caused by the snouts are based on modeling efforts by PennDOT.
The losses associated with the Snouts are dependent on the size of the outlet pipe and size
of the Snout (refer to Appendix C for a detailed table of the losses associated with the
Snouts). Table 4.2 lists the losses associated with the Snouts used for the CIPO project.
Table 4.2. Values for Entrance Losses.
Diameter of Exit Pipe Size of Snout Specified Entrance Loss Coefficient
48" 72FTB 2.4
The proposed storm sewer has minimal cover due to unavoidable existing utility conflicts.
Pre-Cast Concepts (concrete pipe manufacturer) analyzed the strength of the pipe with
respect to the shallow depth of the pipe and the traffic loading that North College Avenue will
be expected to experience. It was determined that Class III RCP will be adequate
throughout the length of the design (refer to Appendix C for documentation on the suggested
class of RCP to be used for the project).
4.3 Inlet Sizing
Inlets were sized using UDInlet. The UDInlet calculations can be found in Appendix C. Inlets
were sized to insure that the EGL was under the grate flowline elevation of the proposed inlet
during the 10-year event. During the 100-year, the EGL will be above the grate flowline
elevation for the majority of the inlets. The majority of the inlets are at grade inlets. The
overflow from the inlets on the west side of North College Avenue will remain in North
College Avenue where it will ultimately flow into the water quality ponds. On the east side of
North College Avenue inlets G2 and E1 were increased to collect the flow that can not be
collected in the upstream inlets. Table 4.3 summarizes the proposed inlet hydraulics for the
10- and 100-year events.
4.4 Ayres Associates
Table 4.3. Inlet Summary.
Inlet 10-year 100-year
Tributary
Basin
Inlet Grate
Elevation Flow HGL EGL Flow HGL EGL
INLET-A1 W02 4964.43 0.58 4962.54 4962.80 13.29 4964.84 4965.32
INLET-A2 W03 4965.1 3.79 4962.90 4963.46 3.61 4965.18 4965.76
INLET-A3 W06 4966.83 2.54 4963.58 4963.67 6.13 4966.93 4967.13
INLET-A4 W07 4967.85 1.84 4964.65 4964.72 4.31 4967.90 4968.14
INLET-A5 W08 4968.83 2.10 4965.64 4965.71 4.74 4968.84 4969.07
INLET-A6 W11 4969.54 1.21 4966.58 4966.67 2.64 4969.57 4970.03
INLET-A7 W12 4970.15 2.32 4966.81 4966.88 5.03 4970.17 4970.59
INLET-A8 W13 4971.19 3.03 4967.56 4967.72 6.53 4971.21 4972.02
INLET-A9 W14 4973.22 2.68 4968.82 4968.97 5.96 4971.74 4972.26
INLET-D E01 4963.77 1.06 4961.26 4961.41 1.55 4963.34 4963.86
INLET-E E04 4964.51 1.78 4962.66 4962.83 11.71 4964.73 4964.91
INLET-F1 W04 4965.95 0.62 4963.09 4963.12 2.22 4965.96 4965.99
INLET-H1 W05 4966.06 1.51 4963.11 4963.16 4.24 4966.16 4966.23
INLET-G1 E05 4966.02 1.07 4963.20 4963.29 6.70 4966.23 4966.33
INLET-G2 E06 4966.85 2.36 4964.21 4964.34 5.35 4966.99 4967.15
INLET-G3 E07 4967.88 1.79 4965.15 4965.25 3.92 4967.93 4968.08
INLET-G4 E08 4969.32 1.30 4966.77 4966.80 2.85 4969.37 4969.50
INLET-G5 E09 4970.53 2.69 4967.74 4967.88 5.83 4970.57 4970.77
INLET-J1 0S1 4961.83 17.41 4962.50 4962.70 25.61 4964.78 4965.20
4.4 Water Quality Pond Analysis
With the addition of curb and gutter, stormwater flows are concentrated and redirected. This
change in flow patterns triggers the need for storm drainage improvements which provide for
the safe passage of vehicles during significant storms. Also, water quality treatment is
required by Federal Law for projects larger than 1 acre to protect surface waters from
pollution. North College Avenue drains to the Poudre River and must be treated prior to
discharging into the River.
The storm flows will be treated in a water quality pond before being discharged into the
Poudre River. The water quality pond will be located just south of the Lake Canal and north
of the Poudre River. The land is currently owned by the City of Fort Collins Stormwater
Department. The required volume for the water quality pond was determined using the
Urban Drainage Flood Control District (UDFCD) method. The total volume required for the
project area is 0.50 ac-ft. The water quality pond will be designed to have a 40-hour drain
time and will therefore meet CDOTs MS4 permit requirements of 80% TSS removal.
The outlet structure for the water quality pond will be the structure recommended by Urban
Drainage. The structure will have an orifice plate sized to provide a 40-hour drain time for
water quality purposes. A Type D and a Type C inlet grate will be set at the water quality
volume elevation. Once the pond fills up and achieves the required volume for water quality
purposes the storm flows will begin to overtop the outlet structure and flow into the grated
inlets. Once through the inlet, the flow will discharge into the Poudre River through a 48-inch
RCP. Eventually the pond will fill up and begin to spill south over a proposed 44 ft long
spillway. The spillway will safely direct flows to the Poudre River.
4.5 Ayres Associates
The runoff volume treated in a water quality pond is typically referred to as the first-flush
volume. This initial flush of runoff is known to carry the most significant non-point pollutant
loads. By restricting the flow out of a water quality pond, water is stored for up to 40 hrs
following a storm thus providing an opportunity for urban pollutants carried by the flow to
settle out. Water quality ponds generally have the following pollutant removal efficiency:
Suspended Sediment: 80-100%
Total Phosphorus: 60-80%
Total Nitrogen: 40-60%
Oxygen Demand: 40-60%
Trace Metals: 60-80%
In general, water quality ponds are considered to have a high overall removal capability.
The outlet of the pond will discharge into a terrace along the south (left) bank of the Poudre
River. The outlet will be protected with Scour Stop transition mats. Scour Stop is a
replacement for hard armor, such as riprap, used to prevent scour and erosion at the outlets
of storm culverts. The channel will be lined with a turf reinforcement mat past the hydraulic
transition point in order to protect the terrace from erosion.
The spillway will be lined with a turf reinforcement mat. This mat will extend from the top of
the spillway and into the terrace along the north (left) bank of the Poudre River. In order to
install the mat the bank and terrace will need to be cleared of most vegetation. This can be
done by hand to minimize the impacts that large equipment would have on the banks of the
river as well as to the roots of the existing plants. Native soil, approximately 0.6 inch thick,
will be placed on top of the cleared land. This soil will be graded with an excavator at the top
of the bank. The soil will be graded so as to create a smooth and solid surface for the TRM
to be installed on top of. The smooth surface is required so that the voids between the TRM
and surface of the soil will be minimized. Voids allow water to travel between the TRM and
the soil, thus creating erosion and negating the effects of the TRM. The TRM will not extend
above exiting grade.
The water quality outlet structure in the water quality pond was modeled in EPA SWMM as
an orifice, a weir and an overflow spillway. The orifice is set at the invert of the pond and
models the total opening of the orifice plate. The weir models the overflow grates of the
outlet structure and is set at the water quality water surface elevation. The grates were
modeled as a weir based on off line calculations. The overflow spillway models the overflow
spillway. Offline calculations were performed to size the orifice plate, overflow inlet and the
overflow spillway. Table 4.4 summarizes the hydraulics of the water quality pond.
Table 4.4. Water Quality Pond Summary
Description Elevation Pond Volume(ac-ft) Pond Depth (ft)
Pond invert 4955.66 0.000 0.00
Outlet Pipe Invert 4955.66 0.000 0.00
Orifice Plate Elevation 4955.66 0.000 0.00
Overflow Grate Elevation 4959.6 0.505 3.96
Overflow Spillway Elevation 4962.5 1.919 6.84
2-year WSEL 4960.73 0.914 5.07
10-year WSEL 4961.24 1.153 5.58
100-year WSEL 4963.34 2.701 7.68
WQ WSEL 4959.6 0.505 3.96
4.6 Ayres Associates
All of the storm sewer and water quality calculations for the final design are included in the
Appendix C.
The spillway will be set at elevation 4962.50. It should be noted that in order to achieve this
elevation, the bank of the Poudre River will be lowered in this area by several feet. The
spillway is set at the proposed elevation in order to spill the overtopping flows from the pond
south to the Poudre River without creating ponding in the low spot along North College
Avenue. The existing low spot in North College Avenue, just east of the water quality ponds,
is set at an elevation of 4963.4. Per direction of City of Fort Collins staff, ponding in North
College Avenue was not acceptable during a 100-year flooding event within the North
College Avenue basins.
According to the FEMA published water surface elevations, the 10-year event along the
Poudre River will be contained within the Poudre River. The 50-year flows will overtop the
spillway and fill up the water quality pond. Minimal ponding on North College Avenue will
occur. It should be noted, that the Poudre River overtops west of the ponds and water will
eventually fill up the ponds regardless of the elevation of the spillway. During a 100-year
event, the water surface in the Poudre River is several feet higher than the spillway and of
North College Avenue. Water overtops the banks of the Poudre River regardless of the
elevation of the spillway. The following information is the FEMA published water surface
elevations at the water quality pond outlet:
10-year WESL: 4961.62 ft
50-year WSEL: 4964.13 ft
100-year WSEL: 4965.04 ft
In order to prevent backflow of the Poudre River into the water quality pond outlet and into
the proposed ponds, a Tide Flex Check Mate Valve will be installed at the end of the outlet
pipe. The Check Mate Valve fits into the storm sewer and has a maximum head loss of 2 ft.
4.5 Siphon Under Lake Canal
The siphon of the Lake Canal was modeled using HEC-22. Bend losses were applied to the
manholes upstream and downstream of the Lake Canal due to the extreme change in pipe
slope. The manholes associated with the siphon will contain a grated manhole lid. The
grated manhole lids will help prevent the buildup of pressure in the siphon. The siphon will
contain trash racks at either end to help deter people from entering the siphon.
4.6 Josh Aimes/Lake Canal Flows
Approximately 265 cfs of runoff from existing developments (from Willox to Josh Aimes Ditch)
flows to the Josh Aimes Ditch during a 100-year event. The Josh Aimes ditch travels under
North College Avenue in a 2x6 RCBC. Once across North College Avenue the storm sewer
is connected into a 30" RCP. The 30" RCP outlets into the Lake Canal. The 30" RCP has
capacity of approximately 30 cfs. According to existing contours and weir calculations, the
flow will overtop Josh Aimes ditch and head south to the Lake Canal and east to North
College Avenue. The majority of the flows that get to North College Avenue will flow back to
the west and ultimately back into the Lake Canal. A portion of the flow will cross over North
College Avenue and into the Lake Canal on the east side of North College Avenue.
4.7 Ayres Associates
With the design of the North College Avenue storm sewer system, the flow to the Josh Aimes
ditch is not reduced. The flow is controlled by the surrounding developments and not by the
flow on North College Avenue. With the project a low spot will be added in Woodlawn Drive
and the Lake Canal will be siphoned. The storm flows will overtop Woodlawn Drive and
continue south, over the Lake Canal siphon and to the water quality pond. The flows will
proceed through the water quality ponds where they will eventually spill into the Poudre River
through the spillway located at the south end of the pond.
4.7 Existing System Near Vine Drive
Basins S1 through S4 were created to verify the capacity of the existing storm sewer near
Vine Drive. The existing system was modeled in EPA SWMM. The existing system can
handle the 100-year event and therefore no changes were made to the system. Table 4.5
summarizes the 100-year hydraulics for this system:
Table 4.5. Existing System Near Vine Drive Capacity During 100-Year Event.
Node Rim (ft) Flow (cfs) HGL (ft) EGL (ft)
2-MANHOLE 4967.57 14.37 4963.09 4963.486
3-INLET 4965.59 13.26 4959.34 4959.705
4-INLET 4965.92 10.3 4959.34 4959.591
5-INLET 4963.81 6.52 4959.76 4959.975
6-INLET 4963.71 4.59 4959.95 4960.152
4.8 Utilities
There are a large number of existing utilities within the project corridor, most of which effect
the design in some way. Many of the utilities have been potholed in order to locate all
existing utilities that may conflict with the proposed design. The utility locates were
surveyed, multiple site visits were taken and the existing utility companies were contacted to
help verify the location of the utilities within the project corridor. Table 4.6 provides a list of
the type of utility and contact information for those utilities within the project corridor.
Table 4.6. Existing Utility Information.
Owner
Utility
Contact Person
Contact Number
Utility in
Project Area
City of Fort Collins Light & Power Bruce Vogel (970) 221-6700,
224-6157
Yes
City of Fort Collins Utilities/Stormwater Glen Schlueter (970) 224-6065 Yes
City of Fort Collins Water/Wastewater Roger Buffington (970) 221-6700,
221-6854
Yes
ELCO Water District Water Mike Scheid (970) 493-2044 Yes
Comcast Fiber optic Don Kapperman (970) 567-0245 Yes
Xcel Gas Len Hildebrandt (970) 225-7848 Yes
Qwest Communication and
duct bank
Terry Speer (970) 377-6405 Yes
Greeley Water Dan Moore (970) 350-9814 Yes
The Lake Canal
Company
Lake Canal Don Magnuson (970) 352-0222, cell:
(970) 381-5444
Yes
4.8 Ayres Associates
Based on the utility information collected, the following are the major utilities in the area:
Light and Power:
Light and Power has several electric lines that run parallel to the east side of North
College Avenue. These lines will need to be relocated at several locations throughout
the project site.
Existing street lights, vaults, and meters will be impacted by the proposed roadway
improvements. Removal and replacement of street lights throughout the project corridor
will be necessary. Street lights will be located along the edges of the roadway on both
sides and at intersections. City Light and Power will be responsible for design and
maintenance of the street lights.
Comcast:
Comcast has a direct bury line that runs along the west side of the project area. This line
is shallow in depth and will be in conflict with the road section and excavation and will
need to be relocated.
Comcast has a Fiber optic duct bank that crosses the Hickory/Conifer/North College
Avenue Intersection. This line will not be crossed with new storm sewer. The existing
storm sewer at this intersection will be utilized.
ELCO:
ELCO has three water lines in the project area:
- An existing 24 inch ductile water line on the south side of Conifer that will be difficult
to lower. This line will not be crossed with new storm sewer.
- An existing 14 inch steel water line at the south end of the water quality pond. The
line has been potholed and is in conflict with the pond outlet pipe. This line will need
to be lowered.
- ELCO is also proposing a 48-inch water line at the intersection of Pinon and North
College Avenue. This line has a 60-inch casing pipe. The proposed storm sewer will
have over one foot of clearance over the casing of the pipe.
City Of Fort Collins Water and Wastewater:
The City of Fort Collins has an existing and very old sanitary sewer line which crosses
under North College Avenue at the Lake Canal. However, this line has been abandoned
and no longer creates a problem.
The COFC also has a sanitary sewer crossing under North College Avenue to the north
of Alpine Street. This sanitary is in good shape. Because this line is a gravity system the
actual location is important and therefore has been determined through survey and
potholes. The crown of this line is near the invert of the proposed storm sewer and
therefore a conflict manhole is being proposed at the crossing of the two systems. The
sanitary sewer will be lined with Class IV structural liner. The lining will begin at the
manhole west of North College Avenue and terminate at the manhole along the east side
of North College Avenue.
4.9 Ayres Associates
There are a number of water valves that will need to be adjusted to grade.
There are a number of fire hydrants that will need to be relocated with this project.
Waterline lowerings are required under some of the proposed storm laterals in order to
provide 18-inches of clearance between the water and storm sewer. There are a few
locations where the proposed storm sewer crosses over the existing water lines and 18-
inches of clearance is not met. The clearance was approved by the City of Fort Collins; it
was preferred to not lower the waterlines.
City of Greeley:
The City of Greeley has a 60-inch water line at the intersection of Pinon and North
College Avenue. This water line has a 79-inch casing and creates one of the major
constraints of the project. The proposed storm sewer will have minimal clearance over
the casing pipe. A reinforced concrete slab will be constructed between the pipes to help
disipate the load of the storm sewer.
Qwest:
There is a large Qwest duct bank running north-south along the west side of North
College Avenue. This duct bank can not be moved and due to the location and inverts of
the bank, is difficult to cross with large storm sewer. The laterals will cross the duct bank
with minimal clearance.
There are several Qwest manholes that will need to be adjusted to grade with this project
as well.
A direct bury line travels the length of the project. This line will need to be relocated as it
will be in conflict with the pavement section of North College Avenue.
Xcel:
Xcel has a 4-inch steel gas line that runs along the west side of the street. This line is
located where the proposed storm sewer will be and shall be relocated under the
proposed sidewalk.
Lake Canal:
A single span concrete slab bridge structure currently crosses Lake Canal (CDOT
Structure B-16-AD). A pedestrian bridge on the east side of the Lake Canal Bridge is
proposed to provide safe pedestrian crossings, as well as to enhance the gateway to the
North College District. This bridge is compatible with the vision originally identified in the
North College Corridor Plan and will offer opportunities to highlight the Outdoors/Natural
character of the corridor. The location and type of bridge has been coordinated with the
North Poudre Irrigation Company.
Refer to the utility sheets in Appendix D for more information on each utility.
4.10 Ayres Associates
4.9 Master Plan Drainage (NCDID and NECCO)
The NCDID is the master drainage plan in the North College area. It identifies storm
drainage solutions for each side of North College Avenue maintaining the natural drainage
division created by the high center line of North College Avenue. The North East College
Corridor Outfall (NECCO) project is the final design for the NCDID solution for the east side
of North College Avenue. The NECCO design is predicated on a realigned Vine Drive. The
outfall for the west side of College in the NCDID is along the future Mason Street corridor,
discharging into the Poudre River. Initially, the North College Corridor Improvements Phase
II project investigated the feasibility of implementing recommendations from NCDID and
placing the outfall along the Mason Street Corridor; however, due to funding limitations, it
was quickly determined that these improvements could not be incorporated into the project
without additional sources of funding. The storm drainage improvements have been
designed to accommodate project flows while maintaining compatibility with the NCDID and
NECCO projects. The design does not preclude any of the NCDID or NECCO
improvements, but reduces the flows that will need to be accommodated by these future
outfall systems.
5.1 Ayres Associates
5. POUDRE RIVER FLOODPLAIN AND FLOODWAY
The southern end of the project lies within the Poudre River 500- and 100-year floodplain
and 1- and 1/2-foot floodway. While construction can occur within the floodplains as long as
floodplain development criteria are met, construction within the floodways is much more
complex. The 100-year floodplain represents the area that gets inundated during a 100-year
storm. The floodway refers to the channel of a river or other watercourse and the adjacent
land areas that must be reserved in order to discharge the base flood without cumulatively
increasing the water surface elevation more than a designated height. The Poudre River 1-
foot and 1/2-foot floodway are "no-rise" areas regulated by the City of Fort Collins Floodplain
Administrator. For the Poudre River the City administrates to a half foot floodway. If any fill
is placed within the designated floodway as part of the project then it necessitates the
Conditional Letter of Map Revision/Letter of Map Revision (CLOMR/LOMR) process. This is
required to evaluate the effect of the fill on flood hazards and to create a design that protects
public health, safety, and welfare.
The goal of this project is to design the proposed improvements without any fill within the
floodway. Figure 5.1 shows the existing FEMA floodplain and floodway limits as well as the
City of Fort Collins Poudre River half foot floodway. The FEMA floodplain and floodway can
be found on FEMA FIRM Panel 08069C0977G. No improvements are proposed along the
current effective FEMA cross sections for the Poudre River (as seen in Figure FP-03) and
therefore a hydraulic model update will not be required for FEMA.
The proposed grading within the floodway will be at or below the existing ground surface.
The water quality pond will be broken into two ponds in order to obtain the required volume.
The northern water quality pond will be located completely within the Poudre River 0.5 ft
floodway boundary while the southern pond will be located completely within the Poudre
River 1.0 ft floodway boundary. The ponds must be located within the boundaries to insure
that the existing floodway boundary will not encroach onto land where it does not currently
exist after the project is built. The pond grading will not change the floodway boundaries.
The proposed water surface elevations for the water quality, 2- and 10-year events are below
the existing ground surface.
The proposed water quality pond and pedestrian trail lie within the floodway. The City of Fort
Collins floodplain Administrator informed the design team that the proposed improvements
can be constructed within the floodway as long as all proposed grading is at or below the
existing ground. The pedestrian trail and water quality pond were designed to ensure that all
grading was below existing ground. Exhibits in Appendix C show the extents of the proposed
grading, spot elevations and cross sections through the water quality ponds spaced at 50 ft.
The outlet to the water quality pond will be into the Poudre River. Scour stop is proposed at
the end of the outlet in the Poudre River. The Scour Stop will not extend above the existing
ground.
Vegetation and plantings will be added to the area in such a way as to not restrict Poudre
River Flows, increase the water surface elevation, or increase the existing condition
roughness coefficient. Native grasses and plantings will be used that will lie down during a
flood event.
17+00 18+00 19+00 20+00 22+00 24+00 25+00 26+00
28+00 29+00 30+00 31+00 32+00 34+00 35+00 36+00
21+00 23+00 27+00 33+00
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There will be a pedestrian bridge over the Lake Canal. The bridge will be anchored or the
footings will extend to the calculated scour depth. Any benches added to the area will be
anchored so as not to float during a storm event. If art is to be placed within the floodway, it
will be designed in such a way as to not obstruct flows and will also be anchored. If fences
are added to prevent people from entering the water quality pond, they will not block
conveyance of flood water and will be designed as break-away fences.
In future phases the City of Fort Collins staff will determine who is to maintain the water
quality pond. A floodplain use permit will be completed prior to construction of any kind in
the floodway and floodplain.
6.1 Ayres Associates
6. PEDESTRIAN BRIDGE
A pedestrian bridge is proposed over the Lake Canal. This section describes hydraulic scour
analysis of the proposed structures.
6.1 Location
The pedestrian bridge is located across the Lake Canal in the 100-year Poudre River
Floodplain. This bridge is not within the boundaries of the floodway. The bridge will be
located 30 ft downstream of North College.
6.2 Hydrology
There are a number of different flows that could be used to calculate the potential scour on
the proposed pedestrian bridge.
Decreed Flow
Bank Full Flow
FEMA Poudre River 500-year Floodplain overbank flows
FEMA Poudre River 100-year Floodplain overbank flows
FEMA Poudre River 50-year Floodplain overbank flows
FEMA Poudre River 10-year Floodplain overbank flows
Bank Overtopping
The pedestrian bridge hydraulic model was developed with FEMA cross section CD as the
downstream cross section and FEMA cross section CF as the upstream cross section. The
100-year flow was determined by adjusting the flow in the model until the WSEL at the FEMA
cross sections were within half foot of the WSEL provided in the FIS study for the Poudre
River. The 500-, 50-, and 10-year flows were calculated by obtaining a percent of 100-year
flow in the Poudre River to actual flow in the Lake Canal. The percentage was applied to the
10- and 50-year flows provided in the FEMA FIS Study. The bank full was obtained by
adjusting the flow until it started to overtop the banks of the Lake Canal at any of the cross
sections. Table 6.1 summarizes the flows that were developed for the scour analysis:
Table 6.1. Pedestrian Bridge Hydrology.
Description Flow
Decreed Flow 156 cfs
Bank Full 300 cfs
FEMA 100-year 1,500 cfs (Poudre River = 13,300 cfs)
FEMA 500-year 2,718 cfs (Poudre River = 24,100 cfs)
FEMA 50-year 1,150 cfs (Poudre River = 10,200 cfs)
FEMA 10-year 606 cfs (Poudre River = 5,370 cfs)
Brink Overtopping of North College 950 cfs
Bank overtopping is the maximum amount of flow that goes through the bridge opening.
Flows greater than this will start to spill over the banks of the Lake Canal
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6.3 Existing Conditions Model
An existing conditions model was created of the Lake Canal to determine the effects of the
Pedestrian Bridges during the 100-year event. Hydraulic simulations of existing conditions
were made using version 3.1.4 of HEC-RAS, the Corps of Engineers' current modeling
software for 1-dimensional analysis (HEC 2004). A plan view of the HEC-RAS model
schematic is provided in Appendix E.
6.4 Modeling Approach and Assumptions
The HEC-RAS model extends approximately 225 ft upstream and 533 ft downstream of the
North College Avenue bridge. The model includes eleven cross sections that were
developed from field survey and aerial topography. The model was extended upstream and
downstream of the existing bridge to account for the flow contraction and expansion into and
out of the bridge. The existing bridge structure under North College Avenue was modeled
using the HEC-RAS bridge routines. Figure 6.1 shows the HEC-RAS cross section layout
for this analysis.
The HEC-RAS ineffective flow option was used to account for flow contraction and expansion
into and out of the bridge. The downstream starting water-surface elevation was the FEMA
100-year WSEL at cross section CD of 4962.6.
Manning's "n" values of 0.035 for the main channel, 0.045 to 0.12 for the overbanks were
used in the model based upon field observation in conjunction with standard references
(Chow 1959, Barnes 1967). Manning's "n" varies from cross section to cross section based
on land types. The undeveloped land contains a value of 0.045 while the commercial
development contains a value of 0.12. A main channel value of 0.035 was used based on
Chow. The bottom of the canal can be described as "stoney bottom and weedy banks,"
which correlates to a normal value of 0.035.
6.5 Rise in Water Surface Elevation
The normal expectation for bridge replacements in approximate floodplain reaches is that the
replacement will cause no more than 12 inches of rise in base flood elevations as compared
to existing conditions. Table 6.2 shows the effects of the pedestrian bridge the 100-year
WSEL's in the Lake Canal.
Table 6.2. Effects of Pedestrian Bridges.
Description
River Station Existing WSEL (ft) Bridge WSEL (ft) Difference WSEL (ft)
1086 4965.43 4965.43 0
1043 4965.21 4965.22 0.01
900 4965.21 4965.22 0.01
875 4965.16 4965.17 0.01
861 4965.09 4965.11 0.02
North College Avenue 824 0
774 4964.41 4964.49 0.08
Ped Bridge 767
761 4963.78 4963.78 0
740 4963.76 4963.76 0
644 4963.14 4963.14 0
493 4962.65 4962.65 0
241 4962.6 4962.6 0
The maximum rise in water surface elevation is 0.08 ft. This is less than the allowed rise in a
FEMA floodplain.
1086
1043
900
861
740
875
761
CF
644
493
241 CD
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6.6 Freeboard
Based upon Equation 6.1 and Figure 6.2 (taken from the CDOT drainage design manual
criteria), the required freeboard for the proposed bridge is summarized in Table 6.3 below.
Freeboard 0 . 1 Q 0 . 3 0 . 008 V 2 (6.1)
Figure 6.2. Freeboard for bridge on continuous grade (CDOT 2004).
Table 6.3. Freeboard Summary.
Event
Low Chord
WSEL
Required
Freeboard
Actual
Freeboard
100-year 4964.49 1.31 -0.49
50-year 4962.96 1.53 1.04
10-year 4962.46 0.92 1.54
Decree 4959.71 0.53 4.29
Bank Full
4964.00
4961.02 0.67 2.98
Providing adequate freeboard for the 100-year flood is not possible given the site constraints.
The bridge meets the required freeboard for the 10-year event. The bridge will have footings
that extend to the maximum calculated scour depth.
6.7 Preventing Failure Due to Scour
To determine the scour potential at the proposed pedestrian bridge over Lake Canal, a HEC-
RAS model was created to simulate the hydraulic conditions during various flood events.
The model includes the pedestrian bridge on the east side of North College Avenue as well
as the North College Avenue bridge. The pedestrian bridge is a single-span bridge, thus it
does not have piers and therefore won't have any pier scour. However, the bridges needed
to be evaluated for both contraction scour, as well as abutment scour. The scour evaluation
was performed in accordance with FHWA publication HEC-18 "Evaluating Scour at Bridges"
(Richardson and Davis 2001). Due to the configuration of the bridges, pressure scour was
not calculated and is considered to be minimal. Once the bridge starts to experience
pressure conditions, the banks of the Lake Canal are overtopped and relief is provided by
overtopping the bridge.
6.5 Ayres Associates
6.7.1 Contraction Scour
In this situation the pedestrian bridge has a greater span (50 ft) than the North College
Avenue bridge (24 ft). Therefore the contraction scour at the existing bridge will be greater
than at the pedestrian bridge. Also, the pedestrian bridge is at grade with the sidewalks,
which don't have an embankment associated with them. Once flow leaves the banks of the
Lake Canal, it will not be forced back into the channel at the pedestrian bridge. There is,
however, an embankment associated with the North College Avenue bridge. Due to the
above two conditions, the scour at North College Avenue will be greater than the scour seen
at either of the pedestrian bridges. For this scour analysis, the scour depth was calculated
for the North College Avenue bridge and then assigned to the pedestrian bridge.
Contraction scour calculations were performed in accordance with the HEC-18 (Richardson
et al. 2001). Contraction scour can be either live-bed in which bed sediment is flowing into
the bridge waterway from upstream, or clear-water in which the water entering the bridge
waterway is not transporting sediment.
The contraction scour calculations were made assuming that the cobble armor layer was
disturbed, exposing the finer gravel and sand beneath the armor. This is a live-bed scenario
because the brink overtopping average channel velocities upstream of the bridge are
adequate to entrain the majority of this gravel and sand. Even with this somewhat
conservative assumption, the computed contraction scour is zero for both bridges.
Computing the contraction scour, using the live bed equations, results in a negative value,
which indicates that contraction scour is negligible.
6.7.2 Abutment Scour
According to HEC-18 (Evaluating Scour at Bridges) 4th Edition, there are two equations that
can be used to calculate abutment scour; the Froelich's scour equation or the HIRE scour
equation. The HIRE method should be used when the ratio of the length of embankment
projected normal to flow over the depth of flow at the abutment is greater than 25. In the
brink overtopping model the ratio was 410 ft/1.84 ft = 223. Therefore, the HIRE equation was
used. The abutment scour was found to be 7.6 ft on the north abutment and 6.8 on the south
abutment. The footings shall be designed to a depth of 8 ft to prevent failure of the bridges
due to abutment scour.
6.8 Scour Results
A nominal degradation depth of 8.0 ft is assumed at the abutments. Abutment scour can be
negligible if riprap is placed around the abutments as abutment scour countermeasures.
Contraction scour was calculated to be negligible. Appendix E contains the scour calculation
worksheets.
7.1 Ayres Associates
7. EROSION CONTROL
Construction of the proposed project will require implementation of erosion control BMPs to
minimize the amount of sediment carried by wind and water (refer to Appendix F).
7.1 Existing Soil Data
Subsurface conditions encountered in borings consisted of approximately 6 to 7 ft of silty
sand and sandy clay fill over gravelly sand and sandy gravel underlain by sandstone and
clay stone bedrock. Sandstone bedrock was encountered below the sand and gravel at
depths ranging from 14 to 17.5 ft. Clay stone was encountered at depths of 30 to 32.5 ft.
The sand and gravel encountered were dense to very dense and the bedrock was very hard.
Groundwater levels were measured at depths ranging from 6.5 to 10 ft below the existing
ground surface.
The materials found can be excavated using conventional heavy-duty excavation equipment.
Excavations into the gravelly sands will likely encounter caving conditions. Excavations
should be sloped or shored to meet local, State and Federal safety regulations. The clay
solids classify as type B soils and the sands as type C soils.
7.2 Existing Vegetation, Including Percent Cover
The majority of the site is currently developed with the ground surface being a paved surface
such as asphalt or concrete. The location where the water quality pond is to be constructed
mainly consists of tall grasses, weeds and trees. The percent impervious for the existing
water quality pond land is approximately 5%, the rest of the project is approximately 95%.
7.3 Temporary Sediment/Erosion Control Methods
The erosion control methods to be implemented during the construction of the proposed
storm sewer can be seen on the Erosion Control Sheets in the construction plans and the
SWMP.
Erosion control BMPs for the proposed project will include wattle dikes set across all flow
paths determined by the general grading plan. The wattle dikes are placed in the flow paths
for each 2 ft of vertical drop to slow the conveyance of water and prevent significant erosion
before vegetation is installed. Gutter protection is to be placed at a 45 degree angle toward
flow in the street flowline, anywhere that the stormwater runoff and sediment may exit the
site via curb and gutter. Silt fencing will be installed around the construction site as
necessary to prevent sediment from leaving the site during construction. Silt fence will also
be placed around the soil stockpiles. Drop inlet wattle protection will be installed around
each existing and proposed inlet, grated manhole lid, and pond outlet structure to prevent
sediment from leaving the project site and entering the Poudre River or downstream
stormwater facilities. Straw mulch will be applied after seeding to prevent erosion from runoff
and help establish plant cover. A vehicle-tracking pad is to be installed at the water quality
pond to prevent mud from being carried off site on vehicle tires. Vehicle tracking pads must
also be provided at any other access locations to the worksite.
Existing vegetation shall be preserved where possible. All disturbed areas not in the
roadway or greenbelt shall have temporary vegetation seed applied within 30 days of initial
disturbance. After seeding, hay or straw mulch shall be applied over the seed at a rate of 1.5
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ton/ac minimum, and the mulch shall be adequately anchored, tacked, or crimped into the
soil. Those roads that are to be paved as part of the project must have a 1-inch layer of
gravel mulch applied at a rate of at least 135 ton/ac immediately after grading is completed.
The placement structure shall be applied within 30 days after the utilities have been installed.
If the disturbed areas will not be constructed upon within one growing season, a permanent
seed shall be applied. After seeding, a hay or straw mulch shall be applied over the seed at
a minimum rate of 1.5ton/ac, and the mulch shall be adequately anchored, tacked or crimped
into the soil.
The above structural practices are temporary and must be installed prior to any grading or
construction on the project site. Temporary sediment control measures shall be checked
regularly and after storms for silt buildup. Silt fence shall be properly installed and
maintained including checking for undermining. Curb inlet protection shall be checked for
openings and silt buildup, if necessary clean or replace gravel to maintain a protective barrier
around all inlets which may receive stormwater. Erosion and sediment control measures
must be replaced or repaired as needed during regular inspections. The temporary
structures must be maintained until the site has uniform cover equivalent to 70% of existing
site conditions. Cover may include vegetation in the interim condition.
7.4 Sediment/Erosion Control Methods
BMPs must be installed prior to any grading or construction on the project site. Temporary
sediment control measures shall be checked regularly and after storms for silt buildup. Silt
fences shall be properly installed and maintained including checking for undermining. Inlet
protection shall be checked for silt buildup, if necessary clean or replace gravel to maintain a
protective barrier around all inlets which may receive stormwater. Erosion and sediment
control measures must be replaced or repaired as needed during regular inspections. The
temporary structures must be maintained until the site has uniform cover equivalent to 70%
of existing site conditions. Cover may include vegetation in the interim condition (see the
erosion control details, plans and specs).
Following site construction the goal is to achieve a stabilized cover condition to provide long
term stormwater protection. Stabilization is quantified by achieving uniform cover equal to
70% of the pre-disturbance condition. Final stabilization shall be achieved by installation of
the permanent erosion control methods. Immediately after the storm sewer improvements
have been constructed, permanent erosion control practices are to be installed and
maintained. Temporary erosion and sediment control measures can be removed after
establishment of permanent stable vegetation to the satisfaction of the City of Fort Collins
inspector.
1. Paving: All existing streets shall be repaved prior to the completion of the project. The
post-construction condition for approximately 20% of the project site will be re-surfaced
with concrete walkways, concrete curbs, gutters and asphalt pavement.
2. Surface Roughening/Grading Techniques/Embankment Protector: Any disturbed
slopes adjacent to the Poudre River shall be protected with redundant BMPs. BMPs
shall be dependant on the time of year and phase of construction. Toes of temporary
slopes shall be protected by BMP (i.e., silt fence). Slopes still being worked on shall be
left in a roughened condition at the end of the day or temporary mulch shall be applied. If
drainage from roadway is directed towards new, incomplete slopes, toes of slopes shall
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be protected by placing a berm at the end of the day or other BMPs as directed.
Temporary seeding and mulch shall be used on the graded slopes of the Poudre River
and the water quality pond to stabilize grades prior to when permanent seeding is in
place.
3. Seeding Permanent: All un-paved disturbed areas shall be reseeded to match native
ground cover, unless otherwise specified on the landscape plans, soon after construction
or grading as weather permits. This provides the opportunity for pollutants to settle out of
the stormwater runoff.
Seeding is used to control runoff and erosion on disturbed areas. Drill seeding shall
occur on slopes flatter than 2:1 and shall occur on the contour of the slope. Completed
areas (any portion of a slope that is at final grade) shall be seeded within 48 hours during
seeding seasons. Seeded areas shall be inspected frequently for areas of failure.
When Engineer approves the top portion of the slope (approximately 15 ft) can remain
unseeded for paving operations to occur. Once paving operations are completed in an
area, shouldering shall occur immediately. Seeding per section 9 of the SWMP shall
then take place within 48 hours. Slopes that had been previously seeded and were
disturbed by paving/shouldering operations shall be reseeded at no additional cost to the
project.
4. Seeding Temporary: Temporary seeding shall be used to stabilize slopes until final
grades are reached or until permanent seeding can be applied.
5. Soil Retention Blanket (SRB) (also called out as a Turf Reinforcement Mat on the
plans): SRB is a permanent erosion control feature that is to be placed at the spillway
in-between water quality ponds as well as at the spillway into the Poudre River. SRB
shall also be installed at the end of the curb and gutter at the north end of the water
quality pond. The local storm runoff will exit the curb and gutter and sheet flow to the
water quality pond, SRB is required to prevent erosion.
Soils shall be properly prepared prior to placing blanket. On Slopes when seeding
cannot occur due to seasonal constraints, a temporary berm, erosion log or other BMP
shall be placed at the top of slope to prevent stormwater from flowing onto the slope and
causing erosion. In addition flexible growth medium or mulch/mulch tactifier shall be
applied on the slopes. If erosion occurs on slope, flexible growth medium or mulch/mulch
tackifier shall be replaced by a blanket as a temporary measure. Once seeding can
occur blanket shall be removed and disposed of and a new soil retention blanket shall be
used.
Vegetation along the Poudre River shall be protected where possible. Minimal
disturbance will be required during the construction of the water quality outlet pipe. A soil
retention blanket shall be placed on the bank of the Poudre River. The blanket shall be
installed according to details and specs. Existing Vegetation shall be cut back and a 4-
inch thick layer of soil shall be applied. This will give the existing vegetation a greater
chance of survival. The soil shall be smoothened prior to construction of the blanket/mat
to ensure close contact to the soil. The mat shall be applied around the existing trees.
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6. Protection of trees and mature vegetation: Existing vegetation shall be preserved
where possible. Where existing land is disturbed, temporary seeding is to be initiated
until permanent seeding is established.
7. Silt Fences: Silt fences shall be used to capture sediment laden runoff from disturbed
areas during construction. It shall be placed on the contour; ends shall be j-hooked to
prevent water from running around the ends of the fence. A maximum drainage area of
1/4 acre per 100 ft of silt fence; maximum slope length behind the barrier is 100 ft;
maximum gradient behind the barrier is 2:1.
Silt fences shall be installed along the Poudre River and Lake Canal. The fence shall be
installed to minimize the stormwater runoff and sediment into the river and irrigation
channel.
8. Erosion Log Ditch: These are to be placed in the proposed Water Quality pond in the
flowline of the pond. The purpose of the log ditch is to prevent the sediment that from the
slopes of the water quality pond to enter to Poudre River. They are also to be placed in
the Lake Canal during construction of the storm sewer under Lake Canal. The
construction will occur when the canal is dry and therefore can be used.
9. Permanent Sediment Trap/Basin: The water quality pond is considered a permanent
basin. The pond shall be constructed early in the project prior to the construction of the
proposed storm sewer. The pond shall be cleaned as needed during construction.
Cleaning shall be paid for as Sediment Removal and Disposal.
10. Inlet Protection:
a. Storm Drain Inlet Protection: The purpose of the storm drain inlet protections are
to protect the existing and proposed inlets and prevent stormwater and sediment from
entering the existing storm drainage system or receiving bodies of water. Inlet
protections are to be placed at all existing and proposed inlets. If the existing inlets
are to be removed, they require protection until they are removed. Inlets consist of
street inlets as well as pond outlet structures.
b. Erosion Inlet Bale Filter: The purpose of the bale filter is to prevent stormwater and
sediment from entering the existing storm drainage system and the Poudre River.
Bale filters are to be placed on the proposed area inlets (Inlet F-1) as well as the
inlets making up the water quality pond outlet structure.
11. Storm Drain Gutter Protection: Gutter protection is placed along the gutter flowline to
prevent stormwater runoff and sediment from leaving the site via the curb and gutter.
North College slopes from North to South and shall be placed along the entire stretch of
improved roadway. Gutter protection shall also be placed at the corners of all
intersections.
12. Outlet Protection: Scour stop is a permanent erosion control feature and shall be
placed at the end of the proposed storm sewer prior to discharge into the water quality
pond or Poudre River.
7.5 Ayres Associates
13. Stabilized Construction Entrance: A vehicle tracking pad shall be placed at the
entrance into the water quality pond to prevent the spreading of sediment offsite. Mud
and debris should not be tracked along roadways and allowed to enter any non-protected
drainage. Off-site soil tracking shall be controlled by at least monthly removal of
accumulated sediment in the street. More frequent removal of sediment shall occur when
significant buildup is evident.
14. Other (Snout): Snout Oil-Water Debris Separator shall be installed in a manhole
upstream of the water quality pond to prevent the accumulation of trash and sediment in
the water quality pond. A snout will also be installed in the water quality outlet structure
to help eliminate the trash and sediment entering the Poudre River.
15. Other (Water Quality outlet Structure): A water quality outlet structure designed using
Urban Drainage Criteria Manual shall be installed at the water quality pond. The purpose
of the structure is to provide water quality and remove sediment prior to discharging into
the Poudre River.
16. Cleaning of Construction Site: Drainage ditches, pans, and culverts must be cleaned of
debris and sediment.
7.5 Materials Handling and Spill Prevention
A project staging area shall be located in the temporary construction easement. The exact
location of the staging area will be determined by the contractor.
Measures should be undertaken to control building materials, waste and disposal of excess
asphalt and concrete to ensure these materials do not leave the site and enter the water
quality pond or Poudre River. Asphalt, concrete, building materials, waste and cleanup by-
products should not be discharged into the on-site curb inlets and storm sewer systems nor
should they be allowed to enter the water quality pond, Poudre River or Lake Canal.
Measures should be undertaken to remove excess waste products from the site and dispose
of these waste materials off-site in an appropriate manner.
A temporary concrete washout area as well as a separate designated loading/unloading area
shall be located in the project staging area. The exact location of the washout area will be
determined by the contractor. It is the contractor's responsibility to ensure that the concrete
is handled in the appropriate manner so as not to contaminate the water quality pond,
Poudre River, Lake Canal or surrounding areas. Upon completion of the project the concrete
in the concrete washout area shall be exposed of in an acceptable waste site. The concrete
wash-out area and designated loading/unloading areas shall be re-vegetated to existing or
better conditions.
The heavy equipment contractor shall be responsible for protecting the soil from
Contamination due to any hydrocarbon or other hazardous spills associated with his
contractual obligations. All chemicals used in maintenance (oil, antifreeze, hydraulic fluid,
etc.) are to be stored offsite.
Fertilizers are to be stored in the contractor staging area. The contractor shall be
responsible for preventing contamination in the water quality pond, Poudre River, Lake Canal
and surrounding areas.
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Any periodic refueling of earthmoving equipment on site shall be carefully controlled to
ensure these materials are not spilled on the site and will not enter the water quality pond,
Poudre River or Lake Canal. It shall be the responsibility of the heavy equipment contractor
to designate a fueling area and take appropriate actions to ensure pollution of stormwater
does not occur. The fueling area shall be located within the contractor staging area. The
fueling area shall be at least 100 ft from drainage channels and/or storm sewer systems and
be enclosed by a minimum 12-inch high compacted berm capable of retaining potential spills.
In the event of a spill from the site into an on-site curb inlet or storm sewer system
appropriate measures should be undertaken immediately to contain spilled pollutants and
properly remove the spilled materials along with all contaminated soils and prevent future
spills from occurring. In addition, measures should be undertaken to limit off-site soil tracking
of mud and debris spillage from vehicles leaving the site. Mud and debris should not be
tracked along roadways and allowed to enter any non-protected drainage path.
Several measures are suggested to protect stormwater quality and prevent contaminates
from migrating off-site.
Washing of vehicles or equipment into the storm drainage system is prohibited
Refueling operations should be done in the designated fueling area during dry weather
conditions and on level ground
Potential flow paths for spills should be assessed prior to any fuel or hazardous
substance transfer
Ample absorbent material and containment should be available to contain a spill
Any storm drain conveyance within a containment area should be protected with berms
or plugs
Hazardous materials such as fuel, solvent or fertilizer used on site should be in a secure
covered area
No dedicated concrete or asphalt batch plants shall exist on the site
7.6 Inspection and Maintenance
The erosion control measures will be inspected daily during construction. The inspection
must include observation of the construction site perimeter and discharge points (including
into a storm sewer system), all disturbed areas, any areas used for material storage that are
exposed to precipitation, any area used for washing of machinery, the vehicle tracking
control pads, and any other erosion and sediment control measures. Silt fence and other
barriers will be checked for undermining and bypass and repaired or expanded as needed.
The temporary vegetation of bare soils will be checked regularly and areas where it is lost or
damaged will be reseeded. Hazardous materials such as fuel, solvent or fertilizer used on
site should be in a secure covered area.
At a minimum the inspections shall occur for all BMPs every 14 days and after significant
precipitation events (i.e., rainfall, snowmelt, etc.). Installations and modifications as required
by the City of Fort Collins or authorized personnel will be implemented immediately or within
48 hours of notification. Mitigation measures shall be inspected for at least the following.
7.7 Ayres Associates
Accumulation of excess sediment and determination of whether or not the effectiveness
of each structure is significantly reduced. Removal of accumulated sediment shall occur
once a 50% reduction of the design storage capacity becomes evident.
Damage to structures that need repairing to ensure their effectiveness. Addition or
elimination of sediment and/or erosion control measures that are designed to control the
movement of soil particles in a practical and effective manner.
Immediate repair and/or replacement of necessary mitigation measures when total
failures are found.
A site log should be kept up to date to record inspections, repairs and maintenance.
Additionally any spills should be fully documented. Include what the spill material was,
reason for spill, date, time of start and finish of spill, quantity, location, weather conditions,
who was contacted, how the spill was cleaned, impact to environment, and method of
disposal of cleanup materials.
All construction activities must also comply with the State of Colorado permitting process for
Stormwater Discharges Associated with Construction Activity. A Colorado Department of
Public Health and Environment CDPHE Construction Permit will be required before any
construction or grading activity can begin.
8.1 Ayres Associates
8. REFERENCES
Adopted by Larimer County, City of Loveland, City of Fort Collins, Larimer County Urban
Area Street Standards, Repealed and Reenacted April 1, 2007.
Adopted by The Transportation Commission of Colorado, State Highway Access Code,
Volume 2, Code of Colorado Regulations 601-1, August 31, 1998.
American Association of State Highway and Transportation Officials, 2004. Geometric
Design of Highways and Streets 2004, Fifth Edition.
Ayres Associates Inc, 2005. North College Drainage Improvements Design (NCDID)
Alternative Analysis Report.
Ayres Associates Inc, 2008. New Vine Drive Realignment Conceptual Plan.
Ayres Associates Inc, 2009. Northeast College Corridor Outfall (NECCO) Final Design
Report, February.
City of Fort Collins Utilities Department Stormwater Division, 1997. Storm Drainage Design
Criteria and Construction Standards.
Colorado Department of Transportation, 2004. Drainage Design Manual.
Colorado Department of Transportation Safety and Traffic Engineering Branch Safety
Engineering and Analysis Group, 2009. Safety Assessment (SH 287C Traffic Safety
Corridor Review Region 4 SH 287C (MP 347.25 to MP 348.54), June 4, 2009.
PBS&J, LSA Associates, 2004. Coley/Forrest, Intermountain Corporate Affairs, Fort Collins
Transportation Master Plan 2004, February.
Urban Drainage and Flood Control District, 2004. Drainage Design Manual.
LINE TABLE
LINE LENGTH BEARING BEGIN
NORTHING
BEGIN
EASTING
END
NORTHING
END
EASTING
BEGIN
ELEV
END
ELEV
1" = 20' 1" = 40'
L1
L2
L3
L4
L5
L6
L7
L8
L9
L10
L11
L12
L13
L14
3.7
12.9
9.6
11.2
65.5
73.0
100.9
24.6
18.6
7.7
13.9
17.8
22.8
47.6
S00°00'00"W
S37°24'17"E
S04°03'32"E
S41°01'46"E
S10°09'33"E
S09°21'23"W
S08°14'47"E
S06°34'09"W
S22°42'02"W
S00°37'20"W
S19°18'32"E
S21°31'47"W
S08°45'10"E
S54°46'10"W
134101
134082
134058
134043
1" = 20' 1" = 40'
NORTH COLLEGE AVENUE IMPROVEMENTS
POND GRADING AND CROSS SECTION MAP
WQ-02 of 5
J. MICHAELSEN
J. MICHAELSEN
WTR QUALITY
A A A A A
A A
A A A
PL PL PL
PL PL
PL PL
PL
PL PL
PL
PL PL
PL PL
1" = 20' 1" = 40'
NORTH COLLEGE AVENUE IMPROVEMENTS
POND GRADING AND CROSS SECTION MAP
WQ-03 of 5
J. MICHAELSEN
J. MICHAELSEN
WTR QUALITY
PL
PL
PL
PL
PL
PL
PL
PL
PL
PL
PL PL PL PL PL
PL PL PL PL PL
PL
1" = 20' 1" = 40'
NORTH COLLEGE AVENUE IMPROVEMENTS
WQ POND TYPICAL CROSS SECTION
WQ-04 of 5
J. MICHAELSEN
J. MICHAELSEN
WTR QUALITY
NORTH COLLEGE AVENUE IMPROVEMENTS
FLOODPLAIN/FLOODWAY
WQ-05 of 5
J. MICHAELSEN
J. MICHAELSEN
STORM
LINE TABLE
LINE LENGTH BEARING BEGIN
NORTHING
BEGIN
EASTING
END
NORTHING
END
EASTING
L1 39.8 S80°06'56"E 134703 194681 134696 194720
L2 62.2 S75°17'14"E 134696 194720 134680 194780
L3 35.4 S76°39'33"E 134680 194780 134672 194815
L4 44.4 S85°30'50"E 134672 194815 134668 194859
L5 22.9 S82°30'43"E 134668 194859 134665 194882
L6 18.5 S76°48'25"E 134665 194882 134661 194900
L7 19.2 S65°29'12"E 134661 194900 134653 194917
L8 15.8 S69°06'17"E 134653 194917 134648 194932
1" = 100' 1" = 200'
L8
L7
L6
L5
L4
L3
L2
L1
17+00 18+00 19+00 20+00 22+00 24+00 25+00 26+00
28+00 29+00 30+00 31+00 32+00 34+00 35+00 36+00
21+00 23+00 27+00 33+00
1086
1043
900
861
740
875
761
CF
644
493
241 CD
LEGEND
W
G
FO
E
T
N/A N/A
CONTACTS NOTES
OWNER UTILITY CONTACT PERSON CONTACT NUMBER
OHE
PL
NORTH COLLEGE AVENUE IMPROVEMENTS
GENERAL UTILITY PLAN
UT-01 of 7
J. MICHAELSEN
J. MICHAELSEN
UTILITIES
E
T
T
W
FO
T
G
W
FIRE HYDRANT NOTES
E
PLAN DESCRIPTION AND CORRESPONDING PAY ITEM
1" = 20' 1" = 40'
NORTH COLLEGE AVENUE IMPROVEMENTS
GENERAL UTILITY PLAN
UT-02 of 7
J. MICHAELSEN
J. MICHAELSEN
UTILITIES
A A A
A A
A A A
PL
A A A A A
A A
A A A A
A
PL PL
PL PL PL
PL PL
PL PL
PL
PL PL
PL
PL PL
PL PL
PL
PL
PL
PL
PL
PL
PL
PL
PL
17+00 18+00 19+00
W W W W
W W W W W
W W W W W W W
W
W
W W
G G
W W W
W W
W
W W
W W W W W W W W W W
W W W
W W W
FO
FO
FO
FO FO
FO
FO FO FO FO
FO FO
FO
FO FO
FO
FO FO FO
FO
1" = 20' 1" = 40'
NORTH COLLEGE AVENUE IMPROVEMENTS
GENERAL UTILITY PLAN
UT-03 of 7
J. MICHAELSEN
J. MICHAELSEN
UTILITIES
PL PL
PL PL PL
PL PL PL
PL PL
PL PL
PL PL PL
PL
PL
PL
PL PL PL PL
PL PL PL PL PL
PL PL PL PL
20+00 21+00 22+00 23+00 24+00 25+00
W
W W W W
W W
E E E
E E E E E E E E
E E E E E
E
FO
FO
FO FO FO
FO FO FO
FO
FO FO FO FO
FO FO FO
FO
FO FO FO FO FO
FO
O
FO FO
G G
G G
G G
G
G
G G
G G
G
G G
G
G G G G
G G G G G G
G G G G G G
G
G
G
G
E E E
E
E
E E E E E
1" = 20' 1" = 40'
NORTH COLLEGE AVENUE IMPROVEMENTS
GENERAL UTILITY PLAN
UT-04 of 7
J. MICHAELSEN
J. MICHAELSEN
UTILITIES
PL PL PL PL
PL PL PL
PL PL
PL PL
PL PL
PL PL
PL PL
25+00 26+00 27+00 28+00 29+00 30+00 31+00
W
W W W W
G G G G G
G G
G G G G G G G
W W W W W W W W W W
W
W W W
W W W W
W W W W W W W W W W W
G G G G G G G G G G G G G
G G
G G G G G
G
G
G
W
W
W
W
W W
W W
E E E E
E E
E E
E E E E
FO FO
FO FO FO
FO FO FO
FO FO FO FO
FO FO FO FO
FO FO FO
FO
FO FO FO FO
G
G
G G
G G
G G
G
G G G G G
G
G
G
E
1" = 20' 1" = 40'
NORTH COLLEGE AVENUE IMPROVEMENTS
GENERAL UTILITY PLAN
UT-05 of 7
J. MICHAELSEN
J. MICHAELSEN
UTILITIES
PL PL PL PL PL
PL PL
PL PL
PL PL PL
PL PL
PL PL PL PL
PL PL
PL PL
31+00 32+00 33+00 34+00 35+00 36+00
G G G G
G G G G
G
G
G G
G G
G G
G G G
G
G
G G G G
G
G
G G
G
G G
G
E
E E E
FO FO
FO FO FO FO FO
FO
FO FO FO FO
FO FO FO FO FO
FO FO FO FO
FO FO FO FO
G G
G G G
G G
G G
G G G
G
G
E E
E E E E E E
E E E
E
E E E
E E E E
E E E E
E E E E E
E
E E
E
1" = 20' 1" = 40'
NORTH COLLEGE AVENUE IMPROVEMENTS
GENERAL UTILITY PLAN
UT-06 of 7
J. MICHAELSEN
J. MICHAELSEN
UTILITIES
PL PL PL PL
PL PL PL
PL PL PL PL
PL PL PL PL
PL PL PL PL
37+00 38+00 39+00 40+00 41+00 42+00
W
W W W W W
W W W W W
W
W W W W
T T T T T T T T
T T T
T
FO FO FO FO FO FO
FO
FO FO
FO FO FO FO FO
G
G G G G
G
G G G
G G G
W W
W
E E
E
E E
FO FO FO FO
FO FO
FO FO FO FO
FO FO FO FO FO FO
FO FO FO
FO FO FO FO FO
FO FO FO
FO FO
FO
FO FO
G G G G
G G G G
G G G G
G
G G G G
G G G G G
G G G G G
G G G
E
E E E
E
E E
E
E
E
1" = 20' 1" = 40'
NORTH COLLEGE AVENUE IMPROVEMENTS
GENERAL UTILITY PLAN
UT-07 of 7
J. MICHAELSEN
J. MICHAELSEN
UTILITIES
PL PL PL PL
PL PL PL PL
PL PL PL PL
42+00 43+00 44+00 45+00 46+00 47+00
W W W W W W W W W
W W
W W W
T T
FO FO FO FO
FO FO FO FO FO
T T T T T
T T
G G G G G
FO FO FO FO FO FO FO
FO FO FO FO FO FO FO
FO FO FO FO FO FO
FO FO FO
FO FO
FO FO FO FO
G G G
G G G
G G G
G G G
G
G
G G G
G
G G G G G G
G G G G
G G G
G G G
G G
G G G G
G
G G
E
E E
E
E
E E E
W W W
W
W W W W W
W W W
W W
W W W
W
W W
W W W
W
W W W
W W W W W
W W W
NORTH COLLEGE AVENUE IMPROVEMENTS
EROSION CONTROL PLAN
EC-01 of 6
J. MICHAELSEN
J. MICHAELSEN
EROSION
1" = 20' 1" = 40'
SF
NOTES LEGEND
20:1
A A A A A A A
A A
A A A
A A
A A A A
A
PL PL PL
PL PL
PL PL
PL
PL PL
PL
PL PL
PL PL
PL
PL
PL
PL
PL
17+00 18+00
SF
SF
SF SF SF
SF
NORTH COLLEGE AVENUE IMPROVEMENTS
EROSION CONTROL PLAN
EC-02 of 6
J. MICHAELSEN
J. MICHAELSEN
EROSION
1" = 20' 1" = 40'
NOTES
LEGEND
SF
20:1
PL
PL PL
PL PL
PL
PL
PL PL
PL
PL PL
PL
PL
PL
PL
PL PL PL PL PL
PL PL PL PL
PL
PL PL PL PL PL
19+00 20+00 21+00 22+00 23+00 24+00
SF
SF
SF SF
SF
NORTH COLLEGE AVENUE IMPROVEMENTS
EROSION CONTROL PLAN
EC-03 of 6
J. MICHAELSEN
J. MICHAELSEN
EROSION
1" = 20' 1" = 40'
SF
NOTES LEGEND
20:1
PL PL PL PL
PL PL
PL PL
PL
PL
PL PL
PL
PL PL PL PL
24+00 25+00 26+00 27+00 28+00 29+00
S
F
NORTH COLLEGE AVENUE IMPROVEMENTS
EROSION CONTROL PLAN
EC-04 of 6
J. MICHAELSEN
J. MICHAELSEN
EROSION
1" = 20' 1" = 40'
SF
NOTES LEGEND
20:1
PL PL PL
PL
PL
PL
PL PL
PL PL
PL PL
PL PL PL
PL PL
30+00 31+00 32+00 33+00 34+00 35+00
SF SF SF
SF
NORTH COLLEGE AVENUE IMPROVEMENTS
EROSION CONTROL PLAN
EC-05 of 6
J. MICHAELSEN
J. MICHAELSEN
EROSION
1" = 20' 1" = 40'
SF
NOTES LEGEND
20:1
P
L PL PL
PL
PL PL
PL PL PL
PL PL
PL PL PL
PL PL PL
PL PL
35+00 36+00 37+00 38+00 39+00 40+00 41+00
20:1
NORTH COLLEGE AVENUE IMPROVEMENTS
EROSION CONTROL PLAN
EC-06 of 6
J. MICHAELSEN
J. MICHAELSEN
EROSION
1" = 20' 1" = 40'
SF
NOTES LEGEND
20:1
PL PL
PL PL
PL PL
PL PL PL PL
41+00 42+00 43+00 44+00 45+00 46+00
20:1
20:1
20:1
20:1
NORTH COLLEGE AVENUE IMPROVEMENTS
SWMP
SW-01 of 4
J. MICHAELSEN
J. MICHAELSEN
SWMP
1. Site Description
Additional information for permitted projects. For information only to fulfill the CDPS-SCP (Colorado Discharge
Permit – Stormwater Construction Permit)
A. Project Site Description: North College Avenue, also US Highway 287 and Colorado State Highway 14 (north of
Jefferson Street), is a major north-south route through the City of Fort Collins which provides the northern
entryway into the City. The arterial provides both local and regional connectivity and carries a large volume
of interstate truck traffic. The project area encompasses approximately 1/2 mile of North College Avenue
between Vine Drive and Hickory Street. The roadway is a four-lane, urban highway with a two-way left turn
lane through most of the corridor. The highway is generally shouldered with open, uncontrolled access, and
limited storm drainage facilities.
This project will entail widening North College, adding curb and gutter and sidewalk and improving the
inadequate existing storm sewer system.
The construction activities on the site will include, but are not limited to: installation of storm sewer,
relocation of existing gas and electric, waterline lowerings, paving, excavation and grading of North College,
landscape in the parkway along the corridor and in the projects’ gateway.
B. Proposed Sequencing For Major Activities: The construction will follow the following general construction
sequence:
1. Relocation of existing utilities along the corridor (gas, electric, waterlines)
2. Siphon of Lake Canal – work in the ditch can only be completed from October 15th to April 15th.
3. Pedestrian Bridge across Lake Canal – work in the ditch can only be completed from October 15th to April
15th.
4. Installation of the water quality pond outfall pipe to the Poudre River
5. Grading of the water quality pond near the Poudre River
6. Installation of the storm sewer from the water quality pond to Lake Canal
7. Installation of the storm sewer and laterals on the west half of the street. Existing storm sewer is to
be connected into the proposed storm sewer as encountered along the corridor.
8. Road grading and widening of North College Avenue to follow the storm sewer installation on the west
half of the street
9. Installation of the storm sewer laterals on the east side of the street
10. Road grading and widening of North College Avenue to follow the storm sewer installation of the east
half of the street.
C. Acres Of Disturbance:
Total area of construction site: +/- 11 acres
Total area of disturbance: +/- 11 acres
Acreage of seeding: +/- 2 acres
Earth disturbance outside the limits of disturbance shown on the plans will be the responsibility of the
Contractor.
D. Existing Soil Data: Subsurface conditions encountered in borings consisted of approximately 6 to 7 feet of
silty sand and sandy clay fill over gravelly sand and sandy gravel underlain by sandstone and clay stone
bedrock. Sandstone bedrock was encountered below the sand and gravel at depths ranging from 14 to 17.5 ft.
Clay stone was encountered at depths of 30 to 32.5 ft. The sand and gravel encountered were dense to very
dense and the bedrock was very hard. Groundwater levels were measured at depths ranging from 6.5 ft to 10 ft
below the existing ground surface.
The materials found can be excavated using conventional heavy-duty excavation equipment. Excavations into the
gravelly sands will likely encounter caving conditions. Excavations should be sloped or shored to meet local,
State and Federal safety regulations. The clay solids classify as type B soils and the sands as type C soils.
E. Existing Vegetation, Including Percent Cover: The majority of the site is currently developed with the ground
surface being a paved surface such as asphalt or concrete. The location where the water quality pond is to be
constructed mainly consists of tall grasses, weeds and trees. The percent impervious for the existing water
quality pond land is approximately 5%, the rest of the project is approximately 95%.
Date of survey: March 2009
F. Potential Pollutants Sources: See First Construction Activities under Potential Pollutant Sources. The ECS
shall prepare a list of all potential pollutants and their locations in accordance with subsection 107.25.
G. Receiving Water:
NORTH COLLEGE AVENUE IMPROVEMENTS
SWMP
SW-02 of 4
J. MICHAELSEN
J. MICHAELSEN
SWMP
4. Stormwater Management Controls First Construction Activities
The Contractor Shall Perform The Following:
A. Obtain Required Permits: Prior to the start of construction, the Contractor shall obtain the required
stormwater permit (SWMP)
B. Designate A SWMP Administrator/Erosion Control Supervisor: (To be filled out at time of construction; designate
the individual(s) responsible for implementing, maintaining and revising SWMP, including the title and contact
information. The activities and responsibilities of the administrator shall address all aspects of the
projects SWMP.)
C. Potential Pollutant Sources: Evaluate, identify and describe all potential sources of pollutants at the site in
accordance with subsection 107.25 and place in the SWMP notebook. All BMPs related to potential pollutants
shall be shown on the SWMP site map by the contractor’s ECS.
D. Contact the COFC, at a minimum, 24 hours prior to start of construction:
D.A. Black, Environmental Regulatory Specialist
Email: Dblack @fcgov.com Office: 970-224-6015 Cell: 970-218-3011 Fax: 970-221-6619
E. Best Management Practices (BMPs) For Stormwater Pollution Prevention
Phased BMP Implementation
During design: fields are marked when used in the SWMP.
During construction: the ECS shall update the checked boxes to match site conditions. Clearly describe the
relationship between the phases of construction and the implementation of BMP controls. Add a narrative to the
table or to the site map describing why the BMPs are being used in specific locations
NON-Structural BMP practices for erosion and sediment control; practices may include, but are not limited to:
BMP Type Of
Control
BMP As
Designed
In Use
On Site
First
Construction
Activities
During
Construction
Interim/Final
Stabilization
Surface Roughening/Grading
Techniques Erosion x X
Seeding Permanent Erosion x X
Seeding Temporary Erosion x X
Mulch/Mulch Tackifier Erosion x X X
Soil Binder Erosion X
Soil Retention Blanket Erosion x X X
Vegetative Buffer Strips Erosion X X X
Protection Of Trees Erosion x X X
Preservation Of Mature
Vegetation
Erosion x X X X
Other
Structural BMP practices for erosion and sediment control; practices may include, but are not limited to:
BMP
TYPE OF
CONTROL
BMP as
Designed
In
NORTH COLLEGE AVENUE IMPROVEMENTS
SWMP
SW-03 of 4
J. MICHAELSEN
J. MICHAELSEN
SWMP
Seeding Permanent:
Seeding is used to control runoff and erosion on disturbed areas. Drill seeding shall occur on slopes flatter than 2:1
and shall occur on the contour of the slope. Completed areas (any portion of a slope that is at final grade) shall be
seeded within 48 hours during seeding seasons. Seeded areas shall be inspected frequently for areas of failure.
When Engineer approves the top portion of the slope (approx 15ft) can remain unseeded for paving operations to occur.
Once paving operations are completed in an area, shouldering shall occur immediately. Seeding per section 9 of the
SWMP shall then take place within 48 hours. Slopes that had been previously seeded and were disturbed by
paving/shouldering operations shall be reseeded at no additional cost to the project.
Seeding Temporary:
Temporary seeding shall be used to stabilize slopes until final grades are reached or until permanent seeding can be
applied.
SEE LANDSCAPE PLANS FOR TEMPORARY SEED MIX
Mulch and Mulch Tracker:
In accordance with subsection 213.03 (a)
Soil Retention Blanket (SRB) (also called out as a Turf Reinforcement Mat on the plans):
SRB is a permanent erosion control feature that is to be placed at the spillway in-between water quality ponds, from
Lake Canal to the water quality pond, as well as at the spillway into the Poudre River. A permanent SRB shall also be
installed at the end of the curb and gutter at the north end of the water quality pond. The local storm runoff will
exit the curb and gutter and sheet flow to the water quality pond, SRB is required to prevent erosion.
If temporary blankets are required because failure of slope where flexible growth medium or mulch is applied on
temporary slopes, the blanket must be 100% biodegradable.
Soils shall be properly prepared prior to placing blanket. On Slopes when seeding cannot occur due to seasonal
constraints, a temporary berm, erosion log or other BMP shall be placed at the top of slope to prevent stormwater from
flowing onto the slope and causing erosion. In addition flexible growth medium or mulch/mulch tactifier shall be
applied on the slopes. If erosion occurs on slope, flexible growth medium or mulch/mulch tackifier shall be replaced
by a blanket as a temporary measure. Once seeding can occur blanket shall be removed and disposed of and a new soil
retention blanket shall be used.
Vegetation along the Poudre River shall be protected where possible. Minimal disturbance will be required during the
construction of the water quality outlet pipe. A soil retention blanket shall be placed on the bank of the Poudre
River. The blanket shall be installed occurring to details and specs. Existing Vegetation shall be cut back and a 4”
thick layer of soil shall be applied. This will give the existing vegetation a greater chance of survival. The soil
shall be smoothened prior to construction of the blanket/mat to ensure close contact to the soil. The mat shall be
applied around the existing trees.
Protection of trees and mature vegetation:
Existing vegetation shall be preserved where possible. Where existing land is disturbed, temporary seeding is to be
initiated until permanent seeding is established.
Silt Fences:
Silt fences shall be used to capture sediment laden runoff from disturbed areas during construction. It shall be
placed on the contour; ends shall be j-hooked to prevent water from running around the ends of the fence. A maximum
drainage area of ¼ acre per 100-ft of silt fence; maximum slope length behind the barrier is 100 ft; maximum gradient
behind the barrier is 2:1.
Silt fences shall be installed along the Poudre River and Lake Canal. The fence shall be installed to minimize the
stormwater runoff and sediment into the river and irrigation channel.
Erosion Bales:
These are to be placed in the proposed Water Quality pond in the flowline of the pond. The purpose of the log ditch is
to prevent the sediment that from the slopes of the water quality pond to enter to Poudre River. They are also to be
placed in the Lake Canal during construction of the storm sewer under Lake Canal. The construction will occur when the
canal is dry and therefore can be used.
Permanent Sediment Trap/Basin:
The water quality pond is considered a permanent basin. The pond shall be constructed early in the project prior to
the construction of the proposed storm sewer. The pond shall be cleaned as needed during construction. Cleaning shall
be paid for as Sediment Removal and Disposal.
Inlet Protection:
Storm Drain Inlet Protection:
NORTH COLLEGE AVENUE IMPROVEMENTS
SWMP
SW-04 of 4
J. MICHAELSEN
J. MICHAELSEN
SWMP
5. During Construction
Responsibilities of the SWMP administrator/erosion control supervisor during construction.
The SWMP should be considered a “living document” that is continuously reviewed and modified. During construction, the
following items shall be added, updated, or amended as needed by the SWMP Administrator/Erosion Control Supervisor (ECS)
in accordance with section 208.
A. Materials Handling And Spill Prevention – see spill prevention control section of the SWMP notebook
B. Stockpile Management - topsoil stockpiles shall be stabilized by spraying a flexible growth medium on the
soil immediately upon stockpile completion. Toes of stockpiles shall be protected immediately with a berm, silt
fence, etc. as directed by the Erosion Control Supervisor with the Engineers approval. Stockpiles and BMPs
shall be marked on the same site map.
Other erodible stockpile (including spoils piles) shall be protected immediately with gravel bags, berms,
erosion logs, etc. as directed. BMP shall be indicated on the site map. When piles need to be accessed during
the day, BMP may be removed for short periods of time for access to the pile. BMP shall be back in place at
the end of the day.
C. Grading And Slope Stabilization – shall be roughened at the end of each day
D. Surface Roughening – see above sections
E. Vehicle Tracking – see above sections
F. Temporary Stabilization – see above sections
G. Concrete Washout
1. Concrete washout water or waste from field laboratories and paving equipment shall be contained in accordance
with subsection 208.05.
H. Saw Cutting – Saw cutting will be vacuumed at the time of cutting. Refer to CDOT spec 208.04G for saw
cutting. The Erosion Control Supervisor shall develop a plan for saw cutting containment to be approved by the
Engineer.
I. New Inlet/Culvert Protection – see above sections
J. Street Cleaning – CDOT nor the CDPS-SCP allow for any accumulation of sediment on paved surfaces or
offsite. Offsite tracking shall be controlled in accordance to section 208.04F.
6. Inspections
A. Inspections shall be in accordance with subsection 208.03 (c).
7. BMP Maintenance
A. Maintenance shall be in accordance with subsection 208.04 (e).
8. Record Keeping
A. Records shall be in accordance with subsection 208.03 (c).
9. Interim And Final Stabilization
A. Seeding Plan: Soil preparation, soil conditioning or topsoil, seeding (native), mulching (weed free), and mulch
tackifier will be required for an estimated 2 acres of disturbed area within the right-of-way limits which are
not surfaced. For the types and rates that shall be used with this project, refer to the Landscape Plans.
B. Seeding Application: Drill seed 0.25 inch to 0.5 inch into the soil. In small areas not accessible to a drill,
hand broadcast at double the rate and rake 0.25 inch to 0.5 inch into soil.
C. Mulching Application: Apply 1 ½ tons of certified weed free hay per acre mechanically crimped into the soil in
combination with an organic mulch tackifier and in accordance to the spec.
D. Special Requirements: Due to high failure rates, hydromulching and/or hydroseeding will not be allowed.
E. Soil Conditioning And Fertilizer Requirements:
1. Fertilizer will not be required on the project.
2. Soil conditioner, organic amendment shall be applied to all seeded areas at 3 cy/1000 sf.
F. Blanket Application: On slopes and ditches requiring a blanket, the blanket shall be placed in lieu of mulch and
mulch tackifier. See SWMP for blanket locations.
G. Reseeding Operations/Corrective Stabilization
Prior To Final Acceptance.
1. Seeded areas shall be reviewed during the 14 day inspections by the Erosion Control Supervisor for bare
soils caused by surface or wind erosion. Bare areas caused by surface or gully erosion, blown away
mulch, etc., shall be re-graded, seeded, mulched and have mulch tackifier (or blanket) applied as
necessary.
2. Areas where seed has not germinated after one season shall be evaluated by the Engineer and CDOT
Landscape Architect. Areas that have not germinated shall have seed, mulch and mulch tackifier (or
blanket) applied. Work shall be done at the expense of the Contractor.
3. The Contractor shall maintain seeding/mulch/tackifier, mow to control weeds or apply herbicide to control
weeds in the seeded areas until final acceptance.
10.Prior To Final Acceptance
A. Final acceptance shall be in accordance with subsection 208.061.
11. Tabulation Of Stormwater Quantities
Pay Item Description Unit Quantity
207 Topsoil Cy 3250
207 Stockpile Topsoil Cy 3250
208 Erosion Log (12 Inch) LF 30
208 Erosion Bales (Weed Free) EA 17
208 Silt Fence (Reinforced) LF 361
208 Concrete Washout Structure Each 1
208 Storm Drain Inlet Protection Each 23
208 Storm Gutter Protection Each 27
208 Stabilized Construction Entrance Each 1
208 Sediment Removal And Disposal LS 1
208 Erosion Control Supervisor LS 1
208 Erosion Bale Inlet Filter Each 10
212 Seeding (Native) Acre 2
212 Seeding (Temporary) Acre 2
213 Mulching (Weed Free Straw) Acre 2
420 TRM Class I Sy 295
420 TRM Class II Sy 1110
420 TRM Class III Sy 1110
420 Transition Mats SF 1305
601 Concrete Class B (Trickle Channel) Cy 40
1. BMP maintenance shall be paid for as: Section 208, Sediment Reomval and Disposal (Lump Sum)
2. It is estimated that 3 concrete washout structures will be required on the project. One concrete washout
structure shall be used for the field laboratories.
3. It is estimated that 1 stabilized construction entrance(s) will be required as directed to minimize
vehicle tracking control. Locate BMP on the SWMP map.
4. Maintenance of seeded areas shall be paid for as: [FA Erosion Control, 212 Seeding (native), 214
Landscape Maintenance Lump Sum, 203 Labor Hours, or included in the price of the work]
The purpose of the storm drain inlet protections are to protect the existing and proposed inlets and prevent storm water
and sediment from entering the existing storm drainage system or receiving bodies of water. Inlet protections are to be
placed at all existing and proposed inlets. If the existing inlets are to be removed, they require protection until they
are removed. Inlets consist of street inlets as well as pond outlet structures.
Erosion Bales Filter:
The purpose of the bale filter is to prevent storm water and sediment from entering the existing storm drainage system
and the Poudre River. Bale filters are to be placed on the proposed area inlets as well as the inlets making up the
water quality pond outlet structure.
Storm Gutter Protection:
Gutter protection is placed along the gutter flowline to prevent storm water runoff and sediment from leaving the site
via the curb and gutter. North College slopes from North to South and shall be placed along the entire stretch of
improved roadway. Gutter protection shall also be placed at the corners of all intersections.
Outlet Protection:
Transition Mats are a permanent erosion control feature and shall be placed at the end of the proposed storm sewer prior
to discharge into the water quality pond or Poudre River.
Stabilized Construction Entrance:
A vehicle tracking pad shall be placed at the entrance into the water quality pond to prevent the spreading of sediment
offsite and shall be installed in accordance to CDOT Spec 208.04. Mud and debris should not be tracked along roadways
and allowed to enter any non-protected drainage. Off-site soil tracking shall be controlled in the street. At a minimum
of Daily removal of sediment shall occur when significant buildup is evident so there is no offsite sediment accumulation
and in accordance to section 208.04F. CDOT nor the CDPS-SCP allow for any accumulation of sediment on paved surfaces or
offsite.
Other:
An Oil-Water-Debris Separator shall be installed in a manhole upstream of the water quality pond to prevent the
accumulation of trash and sediment in the water quality pond.
Other (Water Quality outlet Structure):
A water quality outlet structure designed using Urban Drainage Criteria Manual shall be installed at the water quality
pond. The purpose of the structure is to provide water quality and remove sediment prior to discharging into the Poudre
River.
Dewatering:
Dewatering shall be done in such as manner as to prevent potential pollutants from entering state waters.
F. Offsite Drainage (Run On Water)
1. Describe and record BMPs on the SWMP site map that have been implemented to address run-on water in
accordance with subsection 208.03.
G. Stabilized Construction Entrance/Vehicle Tracking Control
1. BMPs shall be implemented in accordance with subsection 208.04.
H. Perimeter Control
1. Perimeter control shall be established as the first item on the SWMP to prevent the potential for
pollutants leaving the construction site boundaries, entering the stormwater drainage system, or
discharging to state waters.
2. Perimeter control may consist of vegetation buffers, berms, silt fence, erosion logs, existing
landforms, or other BMPs as approved.
3. Perimeter control shall be in accordance with subsection 208.04.
use on
site
FIRST
CONSTRUCTION
ACTIVITIES
DURING
CONSTRUCTION
INTERIM/FINAL
STABILIZATION
Earth Berm/Diversion erosion x x
Check Dams sediment x x
Silt Fence sediment x x x
Erosion Logs sediment x x x
Temporary Sediment
Trap/Basin
sediment x x
Permanent Sediment
Trap/Basin sediment x x x
Embankment Protector erosion x x x
Inlet Protection erosion x x x
Outlet Protection erosion x x
Concrete Washouts construction x x
Stabilized
Construction Entrance
construction x x x
Dewatering sediment x x
Temporary Stream
Crossing
erosion x x
Other: Snout and WQ
Outlet Structure Sediment X x
x Erosion control devices are used to limit the amount of erosion on
site.
x Sediment control devices are designed to capture sediment on the
project site,
x Construction control are BMPs related to construction access and
staging.
x BMP locations are indicated on the site map.
x BMP installation details and general narratives are in the SWMP
notebook.
BMPs must be installed prior to any grading or construction on the project site. Temporary sediment control measures
shall be checked regularly and after storms for silt buildup. Site inspections must occur, at a minimum, every 14 days
and after storm events according to spec 208.03 and the CDPS-SCP. Silt fences shall be properly installed and maintained
including checking for undermining. Inlet protection shall be checked for silt buildup, if necessary clean or replace
gravel to maintain a protective barrier around all inlets which may receive storm water. Erosion and sediment control
measures must be replaced or repaired as needed during regular inspections. The temporary structures must be maintained
until the site has uniform cover equivalent to 70% of existing site conditions. Cover may include vegetation in the
interim condition. Please see the erosion control details, plans and specs.
Following site construction the goal is to achieve a stabilized cover condition to provide long term storm water
protection. Stabilization is quantified by achieving uniform cover equal to 70% of the pre-disturbance condition. Final
stabilization shall be achieved by installation of the permanent erosion control methods. Immediately after the storm
sewer improvements have been constructed, permanent erosion control practices are to be installed and maintained.
Temporary erosion and sediment control measures can be removed after establishment of permanent stable vegetation to the
satisfaction of the City of Fort Collins inspector.
Surface Roughening/Grading Techniques/Embankment Protector:
Any disturbed slopes adjacent to the Poudre River shall be protected with redundant BMPs. BMPs shall be dependant on the
time of year and phase of construction. Toes of temporary slopes shall be protected by BMP (ie: silt fence). Slopes
still being worked on shall be left in a roughened condition at the end of the day or temporary mulch shall be applied.
If drainage from roadway is directed towards new, incomplete slopes, toes of slopes shall be protected by placing a berm
at the end of the day or other BMPs as directed. Temporary seeding and mulch shall be used on the graded slopes of the
Poudre River and the water quality pond to stabilize grades prior to when permanent seeding is in place.
1. Outfall locations: A proposed 36” RCP (at STA 19+45) will outlet the proposed water quality pond and into
the Poudre River. The existing City of Fort Collins storm sewer along North College Avenue from Lake
Canal to the intersection of Hickory and North College shall be picked up in the proposed storm sewer.
There are three ditches in the vicinity of the project site: Josh Aimes Ditch, Lake Canal and Dry Creek.
All of these ditches ultimately flow into the Poudre River.
2. Names of receiving water(s) on site and the ultimate receiving water: The Poudre River
3. Distance ultimate receiving water is from project: The water quality pond discharges into the Poudre
River, therefore it is immediately south of the project site. From the road construction it is
approximately 600ft south.
4. Does the receiving water have an approved TMDL: Yes. The Contractor shall coordinate with the Colorado
Department of Public Health and Environment Water Quality Control Division (the Division) to ensure
appropriate BMPs are incorporated into the plans.
H. Allowable Non-Stormwater Discharges: It is anticipated that the Contractor shall obtain a dewatering permit
from the Colorado Department of Public Health and Environment. Prior to the start of construction the
contractor shall fill out a groundwater discharge permit stating how the groundwater will be handled
during construction and the suggested point of discharge. Landscape irrigation return flows can be
discharged into the proposed storm sewer as long as the water quality pond has been constructed with the
design water quality outlet structure.
5. Groundwater and stormwater dewatering: Discharge to the ground of water from construction dewatering
activities may be authorized provided that:
a. The source is groundwater and/or groundwater combined with stormwater that does not contain pollutants.
b. The source and BMPs are identified in the SWMP.
c. Discharges do not leave the site as surface runoff or to surface waters.
6. If discharges do not meet the above criteria a separate permit from the Department of Health will be
required. Contaminated groundwater requiring coverage under a separate permit may include groundwater
contaminated with pollutants from a landfill, mining activities, industrial pollutant plumes, underground
storage tank, etc.
I. Environmental Impacts:
1. Wetland Impacts: yes, 997 sf of temporary disturbance, 360 sf of permanent disturbance
2. Stream Impacts: yes (Poudre River)
3. Possible Threatened and Endangered Species: none
2. Site Map Components
Pre-construction
A. Construction Site Boundaries Shown in the Erosion Control Plans
B. All Areas Of Ground Surface Disturbance: Shown in the Erosion Control Plans
C. Areas Of Cut And Fill Proposed Contours are shown in the Erosion Control
Plans
D. Location Of All Structural BMPs Identified In The SWMP Shown in the Erosion Control Plans
E. Location Of Non-Structural BMPs As Applicable In The SWMP Shown in the Erosion Control Plans
F. Springs, Stream, Wetlands And Other Surface Water Shown in the Erosion Control Plans
G. Protection Of Trees, Shrubs, Cultural Resources And Mature Vegetation Protected trees are labeled in
the Erosion Control Plans
3. SWMP Administrator For Design: Professional Engineer with ECRUS
W W W W W
W W W W
W W
W W W W
W W W
W
W
W
W
T T
T T T T T T T T T T T T T
T T T T T
T T T T T T T T
T T T T T T T
T
T T T T T
T T T T T T T T
T T T T T T T
T T T
T T T T T T T T T T
T
T T T T T T T
T
T T T T T
T T T T T T T T
T T T T T T T T T T
T
T T T T T T T T T T
OHE OHE
OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE
OHE OHE OHE OHE OHE OHE OHE
T T T T
T T T T
T T T
42+00 43+00 44+00 45+00 46+00 47+00
E
E
E
E
E E E
E
E E E
E
E E
E E E E E
E
E
E
E E E E E E E
E E
E
E
E E E
E
E E E E E E E E E E E
E
E E E
E E E E
E
T T T
T T T
T
W W W
W W
W W W
W W W
W W W
W
W W W W W
W W W W W W W
W W W
W W
W W
W
W
W W W W
W W
W W W W W
W W W W
T T
T T T T T T
T T T T T T T T T T T T T T
T T T T
T T
T T T T T
T T T T T
T T
T T T T T T T T
T T T T T T T T T T T T T T
T T T T
T T T T
T T T
T T T T T
T T
OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE
T T T T T T
T T T T T T
T
T T T T T
T T T T T T
T
T
T
T T
T T T T
T T
37+00 38+00 39+00 40+00 41+00 42+00
S
C
E E E E
E E E E E E E E E E E
E E E E
E
E E E E
E
E
E
E
E E E E
E
W
W
W
W W W
W W W W W W W W
W W
W W W
W W W
W W W W W
W W W W W
W W W W
W W W
W W
E E
T T T T T T T T T T T
T T T T T T
T T T T T T T T T T T T
T T T T T T T T T T T
T T T T T T
T
T T T T T T T T T T T
T T
T T T T T T T
T
T T
T T T T T T T
T
W W W W W W
W W W W
W W W W
OHE OHE OHE
E OHE OHE OHE OHE
E
T T T T T T
T T T
T T T T T T T T T T T
T T T T T T
T T T T T
T T T
31+00 32+00 33+00 34+00 35+00 36+00
E E
E E E E
E E E E E E E
E E E E E E
E
E E E E E E E
E
E E E E E E
E E E E
E
E E E E
E
E E E
E
E E E
E
W
W W
W
W
W
W
W W W W W
W W
W W W W W W
W W W W W W
W
W W W W W W
W W W
W W
W W W W
W W W
W W W
E E E
W W W W
E E E E E E E
E E E E
T
T T T T T T T T
T T
T T T T T T
T
T T T T T T T
T T T T T T T T T
T T T T T T T T T
T
T T T T
T T T T
T T
T T T T T T
T
T T T T T T T
T T T T T T T T T
T T T T T T T T T
W W W W
OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE
W
T T T T
T T T
T T T T T T T T
T
T T T T
T
T T T T T T
T T T T T T T T
25+00 26+00 28+00 29+00 30+00
27+00 31+00
E E
E E
E E E E E
E
E E E E E
E
W
W W
W W
W
W
W W W
W W
W W
W W W
W W W W
W W
W W W
W
W W W W W W
W
W
W W W W
W W W W W W
T
T T T
T T T T T
T T T
T T
T
T T T
T
G
W W W
W
W W
E
E E E E E
E E E
E E
E
E
E E
E E
E E E E E E E E E
E E E E E
G
G G
G G
E E E
E
T T T T T T
T T T T T T
T T T T T T T T T
T T T
T T T T T T T
T T
T T T
T T
T T T
T
T T T T T T T T T T T
T
T T T T T T T T T
T T T
T T T T T T T
T T
T T T
T T
T T T
T
T
T T
T T
T
E E
E E E
T T T T T T T T
T T
T T T T T T T T T
20+00 21+00 22+00 23+00 24+00 25+00
FO FO
FO
FO
FO
G
G
G G G G G G G G G
G
G G
G
G
G G G G G
G G G G
G G G
G G G G G G
G
E
E E E
E
E E
E
E
E E
E E E
E E
E
E
E
E
E E
E
E
E
E E E E
E E E
W
W
W W W
W W W W W
W W W W
T T T T
T T T T
T T T T
T T T T T
T T
E E
E E
E E E
E E
E E E E
E
E
T
T T T T
T T T
T T
T
T
T T T T T T
T T T
T
T
T
T
T T
T T T T T
T T T T T
T
T T T T T T T T
T T
T T T T T
T T T T T
T
T T T T T T T
T
E E E E E E E
E E E E E
E E
G
W
17+00 18+00 19+00
134488
134407
134320
134207
134169
134663
134647
134599
134574
134701
194736
194741
194754
194757
194747
194759
194747
194761
194755
194740
194742
194746
194738
194806
134097
134071
134048
134034
134424
134335
134220
134182
134152
134655
134633
134582
134552
134673
194736
194749
194755
194764
194759
194747
194761
194759
194748
194740
194746
194739
194742
194767
CURVE TABLE
CURVE LENGTH RADIUS DELTA TANGENT CHORD BEARING
C1 16.3 25.0 37°24'17" S18°42'08"E
C2 14.5 25.0 33°20'45" N20°43'54"W
C3 6.5 10.0 36°58'14" S22°32'39"E
C4 17.0 50.0 19°30'56" N00°24'05"W
C5 15.4 50.0 17°36'10" S00°33'18"W
C6 12.9 50.0 14°48'56" N00°50'19"W
C7 14.1 50.0 16°07'53" N14°38'06"E
C8 8.7 25.0 19°55'52" S09°20'36"E
C9 35.6 50.0 40°50'19" N01°06'38"E
C10 7.9 15.0 30°16'57" S06°23'19"W
8.5 16.0
7.5 14.3
3.3 6.3
8.6 16.9
7.7 15.3
6.5 12.9
7.1 14.0
4.4 8.7
18.6 34.9
4.1 7.8
NORTH COLLEGE AVENUE IMPROVEMENTS
WATER QUALITY POND
WQ-01 of 5
J. MICHAELSEN
J. MICHAELSEN
WTR QUALITY
4955.52
4955.43
4955.36
4955.31
4956.46
4956.19
4955.84
4955.73
4955.64
4957.14
4957.07
4956.91
4956.82
4962.00
4955.53
4955.47
4955.39
4955.34
4956.66
4956.41
4956.14
4955.81
4955.69
4957.16
4957.11
4956.97
4956.89
4964.06
L20 21.4 S67°43'20"E 194726 194726 134124 194745
L21 22.9 S78°33'15"E 194745 194745 134120 194768
L22 44.7 N85°28'36"E 194730 194730 134539 194775
LINE TABLE
LINE LENGTH BEARING BEGIN
NORTHING
BEGIN
EASTING
END
NORTHING
END
EASTING
BEGIN
ELEV
END
ELEV
4962.20 4962.20
4962.20 4962.20
4962.50 4962.50
W W W W
W W W
W W W W W W W W W W
G
E E
E
E E E
E E
E
T T
T
T
T
T
T
T
T
T T T T T T T T
T
T T T T T T T T
1
6008
4964.36
LOCWLN
E E E E E E E
E E E E E
E E
G
W
PL PL PL
PL PL
PL PL
PL
PL PL
PL
PL PL
PL PL
PL
PL
COLLEGE AVENUE
E E
E
G G
T T T T T
T T T T
T T T T
T T T T T
T T T
T
T T T T
T T T
T T T
T T T
T
G
E E
E E
E E E E
E E E E E
E E E
E E
E
E
E
E E
G
G G
G G
T T T
T T T T T T T
T T
T T T
T
T
T T T
T T T T T
T T T T T
T
T T T
T T T T T T T
T T
T T T
T T
T T T
T T T T T
T T T T T
T
T
T T
T T
T
E E
E E E
T
PL
PL
PL PL
PL
PL
PL
PL
PL PL PL PL
PL PL PL PL
FO FO FO
FO
FO FO
FO
FO
FO
G
G
G G G G G G G G G G G G
G
G G
G
G
G G G G G
G
G
G G
G
G
G G
G G G G
G G G
G G G G G G
G
G
G G
G G
G
G G G
G
G G G
G G G G G G
G G G G G G
G G G G G
G
G
G
G
G
G
E
E E E
E
E E E
E
E E
E
E E
E E E
E
E
E
E
E
E E
E
E
E
E E E E
E E E
E
E E E E E
E
E
E E
E E E E E
E
E E E E E
E E E E E E E
E
E E E E E E
E E
E E
E
E E E
W
W W
W
W W
WW
W
W
W
W W W
W W W
W W
W W W W
W
W
W W W
W W
W W
W W W
W W W W
W W
W W W
W
W W W W W W
W
W W W W
W W
W W W W W W
W W W W W W
W
W
W
W
W W W W
W W W
W W W
W W W W W W
W W W W W W
T T
T T T
T T T T
T T T T
T T T T T
T
T T
T T T T T
T T T
T T T
T
T T
T
G
W W W W
W W W
W
W W
E E E
E E
E E E
E E
E E E E
E E E E
E
E E E
E E
E
E
E
E E
E E
E E E E E E E E E
E
E E E E E E E E E
E E E E
G
G G
G G
E E
E
T T T T T T T
T T T
T
T
T
T
T T T T T T T
T T T
T
T
T
T
T T
T
T
T T T T T T T
T T T T T T T T T
T T T T T T T T T T T T T T T T T T
T
T T T T T T T T
T T
T
T T T T T T T
T T
T T T
T T
T T T
T T T T T
T T
T T T
T
T T T T T T T T
T T T
T
T T T T T T T
T T T T T T T T T
T T
T T T T T T T T T T T T T T T T
T T T T T T
T T T
T T T
T T T T T T T
T T
T T T
T
T
T T T
T T T T T
T T
T T T
T
T T T T T T T T
T
T T
T T
T
W W W W
E E E E E E E
E E E E E
E
E
G
E E
E E E
OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE
W
W
T
T T T T T T T T T
T T T T T T T T T T T
T T
T
T T T T T T T T
T T T T T
T
T T T
17+00 18+00 19+00 20+00 22+00 24+00 25+00 26+00
21+00 23+00 27+00 28+00 29+00
W
W W W W W W W W W W W
W W W W W W
W W W W
W W W W W
W W W
G G G G G G
G G
T T
W W W W W W W W W W
W
W W W W W W W
W W W W W
W W W
W W W W W W W W W W W W W
FO FO FO FO FO FO FO FO
FO
FO FO
FO FO FO FO FO FO FO
FO FO FO FO FO FO FO FO FO FO FO
T T T T T
T
T
G G G G
G G
G G G G G G G G
G G G G
G
G
G G
G G
G G
G G G
G
G
G G G G
G G G G
G
G
G G
G
G G
G G G
G G G
G
G
W
W
W
W W
W W
W W
W
G G G G G G
FO FO FO FO
FO FO FO FO FO FO FO
FO FO FO FO FO FO FO
FO FO FO FO FO
FO
FO FO FO
FO FO FO FO
FO FO
FO FO FO
FO FO
FO FO FO FO
FO FO
FO FO FO FO
FO FO FO FO FO
FO FO FO FO
FO FO FO FO FO FO FO FO FO
FO FO FO
FO FO FO
FO FO
FO FO FO
FO FO
FO
FO FO
FO
FO FO FO FO
G G
G G
G G
G G G
G G
G G
G G G
G
G G G
G G G G
G G G
G G G
G G G G
G
G G G G
G G G G G
G G
G G G
G G G G G
G G
G G G
G
G G G G G G
G G G G
G G G
G G G
G G
G
G
E
E
E E
E
E E
E
E
E
E
E E E
E E
E
E
E E
E E E E E E
E
E E E E
E
E E
E
E
E E E
E E E
E
E E E
E E E E
E E E E
E E E E E
E
E E
E
E
E
E E E E
E
E E E E E E
E
E
E E E E E E E
E E
E
E
E E
E
E
E E E E E E
T T T
T T T
T
W
W
W
W
W W W
W W W
W W
W W W
W W W
W
W W
W
W W W W W W
W W W
W W
W W W
W
W W
W W W
W
W
W
W W W W W W
W W W
W W W W W W W W
W
W
W W W W W W
W W W W W
W W W W
W
W W W W W W
W
W W W W W
W W W W W W W
W W W
W W
W W
W
W
W W W W
W W W W W
W W W
W W W W W
W W W
W
W W
W W W W
W W
W
W W W W W W
W W W
W W W
W W W W
T T T T T T T T T
T T T T T T
T T T T
T
W W W W
T T T T T
T T T
T T T T T
T T T T T
T T T T T
T T T T T T T T T T
T T T T
T T
T T T T T T T
T T T T T T T
T T
T T
T T T T T T T
T T T
T T
T T T T T T T T T T T T
T T T T T T
T T T T T T T T
T T T T
T T T T T
T T T T T
T T T
T T T T T T T
T T T
T T T T T T T T T T T T T T T T
T T
T T T T T T T T T
T T T
T T T T
T T T T
T T T
T T T T T
T T T T T T T T T T T T
T T T T T T
T T T
T T T T T T T T T
T T
T T T T T T T
T T T
T T T T T
T T
T T T
T T T
T
T T
T T T T T T T
T T T
T T T T T
T T
T T T
T T T
T
W W W W W
W W W W W
OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE
OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE
OHE OHE OHE OHE OHE OHE OHE OHE OHE
OHE OHE OHE OHE OHE OHE OHE
OHE OHE
OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE OHE
W
E
T
T T T T T
T T T T T T T T T T T T T
T T T
T T
T T T T T T T T T
T
T T T T T
T T T T T
T T T
T T T T
T T T T T T
T T
T T T T
T T T T T T
T
T
T
T
T
T T T T
T T T T T T
T T
T T T
29+00 30+00 31+00 32+00 34+00 35+00 36+00 37+00
33+00 38+00 40+00 41+00 42+00 43+00 44+00 46+00
39+00 45+00