HomeMy WebLinkAboutDrainage Reports - 07/27/1995 (3)FO?�'' Ap_nrcrwed Report
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THIS FINAL STORM DRAINAGE STUDY AND REPORT FOR TIMBERLINE ROAD
STREET IMPROVEMENTS (RE —CONSTRUCTION AND WIDENING BETWEEN
MILESTONE DRIVE AND COUNTRYSIDE ANIMAL HOSPITAL) WAS PREPARED BY
LAND DEVELOPMENT SERVICES USING THE CITY OF FORT COLLINS STORM
DRAINAGE DESIGN CRITERIA, dated May, 1984.
The results of this drainage study are reported in the enclosed
text and supporting documents, and are shown in further detail on
the Utility Plans submitted concurrently with this report. This
report is a revision to the report previously submitted on
October 30, 1994.
Signed this 5th_day_Qf_January, 1995.
Dennis L. Donovan, P.E.
Land Development Services
309 W. Harmony Road
Fort Collins, Colorado 80526
Phone (303) 225-9244
FINAL STORM DRAINAGE REPORT FOR TIMBERLINE ROAD STREET IMPROVEMENTS
MILESTONE DRIVE TO COUNTRYSIDE ANIMAL HOSPITAL
I. GENERAL INFORMATION
The portion of Timberline Road that is the subject of this
report is a street re —construction and widening project between
Harmony Road and Horsetooth Road in southeast Fort Collins,
Colorado. A general Vicinity Map of the area is provided at the
end of this report.
The proposed street improvements extend from the future
intersection with Milestone Drive 500 feet north of Harmony Road
to the existing improvements at the south side of the Countryside
Animal Hospital 3,600 feet north of Harmony Road. The street
improvement construction plans for which this report is prepared
are based on centerline stationing to be 50+00 at Harmony Road
and lesser stationing to the north to Station 13+67 at the vet
clinic, or hospital.
This method of stationing was chosen to match a separate
widening and reconstruction project that extends from Milestone
south through the intersection with Harmony Road to about 4,000
feet south of Harmony Road.
All of the street plan and profile sheets, cross—section
information, detail sheets and traffic lane striping plans are
not included as exhibits to this report, but are on file with the
City. Sheet 9 of 10 is included as Exhibit A to the report,
which shows the storm drainage subbasin locations, hydrologic
characteristics, directions of flow, storm drainage facilities,
intersection locations, erosion control, etc.
Exhibit B is also included with this report. It is the
Master Drainage Basin Plan for Timberline Farm, P.U.D., updated
to show the final storm drainage conditions after development of
Sunstone Village 8th Filing and after construction of this street
improvement project.
Within the limits of this construction project are the
pending Milestone Drive and Summerstone Court intersections with
Timberline Road (which are to be built in their entirety), and
the existing Caribou Drive and Lowe Drive intersections (which
are to be partially reconstructed and partially matched into
existing intersection improvements).
The project includes a total reconstruction of the existing
3,100 feet of roadway. Additionally, the east side (only) of
Timberline Road in this project will be widened. This reach of
Timberline Road north of Harmony Road is designated in the City
of Fort Collins as a "Major Arterial Street". This project will
provide a functional interim street width until the arterial
street is constructed to its ultimate width and capacity, by
addi.tional widening in the future.
PA_6E 1
in
FINAL STORM DRAINAGE REPORT FOR TIMBERLINE ROAD STREET IMPROVEMENTS
MILESTONE DRIVE TO COUNTRYSIDE ANIMAL HOSPITAL
According to City plan, the west side and east side of this
street will both be further widened to at some point(s) in the
future to accommodate the ultimate traffic needs. The street
improvements included in this project have been designed to
facilitate any future widening activities.
The westerly side (one—half) of the street will not be
widened at this time, but the existing 20 feet of pavement south
of Caribou Drive and existing 33 feet north of Caribou will be
reconstructed (i.e. torn out and replaced). The easterly
one—half of the entire length of the existing street will be
reconstructed and it will also be widened to the normal arterial
street width of 35 feet from the centerline to the flowline of
the curb and gutter.
The Sunstone Village 8th Filing P.U.O. is a participant in
the improvements, and its developer has agreed to facilitate the
Timberline Road improvements with the cooperation of the City of
Fort Collins and other property owners on the east side of
Timberline adjacent to the project.
In addition to the Sunstone development and the City of Fort
Collins, Timberline Farm, Inc. and Caribou Joint Venture are
participants in the project. Easements are to be granted by
those owners to accomodate the construction and maintenance of
the resulting improvements.
Timberline Road lies north and south. The fall, or slope,
of the land across the adjacent properties is from west to east.
Most of the storm drainage facilities that will drain Timberline
Road and adjacent properties from west to east are already in
place. No additional storm drain crossings of the road will
occur with this project.
There are no active irrigation ditches crossing or within
the construction limits of this street construction project. No
surface runoff onto the street improvement area will occur from
off —site (either from the west or east).
Timberline Road and the adjacent properties are all located
within Reach 2 of the City designated Fox Meadows Drainage
Basin. Basin wide improvements are required for all of the:City
designated "Master" Storm Drainage Basins. Certain basin storm
drainage improvements are identified in each of the Drainage
Basin Utility Construction Plans. All of the Fox Meadows Basin
improvements in the vicinity of this project have already been
completed.
Drainage Basin Fees are collected in each City designated
basin to offset the anticipated cost of basin wide improvements.
Information regarding the City designated Fox Meadows Basin can
also be obtained in current form at the City Storm Water Utility
Department.
FINAL STORM DRAINAGE REPORT FOR TIMBERLINE ROAD STREET IMPROVEMENTS
MILESTONE DRIVE TO COUNTRYSIDE ANIMAL HOSPITAL
Existing storm drainage conditions for this section of
Timberline Road are as follows:
1. The existing street improvements from the Milestone Drive
alignment north to Caribou Drive have a crown in the center of
the road, 20 to 22 feet of pavement on each side, four foot wide
dirt shoulders, and cut or fill slopes from the shoulder to match
existing grade on either side. The existing condition only
accomodates one travel lane for vehicular traffic each way, and
has been a traffic flow constraint for some time.
The side slopes to existing grade from the shoulder vary in
steepness. For most of the length of the improvement project,
the adjacent land is lower than the street itself. Storm runoff
from the existing street will sheet flow east and west away from
the crown directly onto the lower adjacent properties, or into
shallow road side swales that intercept the sheet flow and direct
flows to the existing lower ground.
A ridge line (high point in the street profile) extends
across Timberline just north of the Summerstone Court alignment.
From the crest of the ridge, storm water runoff will flow away
from the existing high point in the street to the west and to the
east as follows:
A. Into a shallow road —side Swale flowing northerly onto vacant
land to the northwest and eventually into an existing storm
drainage system at Caribou Drive. B. Into a roadside ditch
flowing to the south, then westerly into an existing City owned
detention facility known as the Chandler Sump/Wetlands Area. C.
Into and southerly along a shallow roadside swale to another
existing detention pond south and east of the crest. D. To the
north in a roadside Swale and easterly onto lower ground south of
Caribou.
South of the Summerstone Court alignment is a low point, or
"sag vertical curve" in the street. The two existing detention
ponds are on either side of the low point, and storm water runoff
will sheet flow directly off of the street and into the ponds in
that stretch.
Further south from the sag, the street climbs at a very flat
slope to the Milestone Drive alignment. The adjacent properties
are lower than the street and storm water runoff will sheet flow
away from the street to the east and to the west. The flows to
the west then flow northerly into the Chandler Sump detention
facility, while flows off the street to the east continue
easterly across vacant land.
North of Caribou Drive, the street is fully widened (thru
and right turn lanes) on the west side, including curb, gutter,
sidewalk and storm sewer system. Storm water runoff will flow to
FAA 1� 3
FINAL STORM DRAINAGE REPORT FOR TIMBERLINE ROAD STREET IMPROVEMENTS
MILESTONE DRIVE TO COUNTRYSIDE ANIMAL HOSPITAL
the curb and gutter and to existing inlets. The existing storm
sewer system there will carry flows to the north beyond the limit
of this project.
On the east side — north of Caribou — is a wider pavement
section than the existing 22 feet south of Caribou. An asphalt
acceleration lane from Caribou north onto Timberline has been
installed, but no curb and gutter, sidewalk, or storm sewer
system exists. Storm runoff from Timberline in this reach will
sheet flow into a swale that flows northerly to a low point south
of the vet clinic — and then easterly across vacant land.
2. There is an existing 42 inch storm sewer that crosses
Timberline at about station 35+00. It is the storm drainage
outlet for the City owned Chandler Sump/Wetlands Detention Pond
on the west side of Timberline across from Sunstone 8th Filing.
The forty two inch Reinforced Concrete Pipe (RCP) culvert flows
from west to east from Chandler Sump to a storm drain manhole
about 45 feet east of the centerline of the street.
This outfall storm sewer is a "master basin improvement" for
Fox Meadows Basin. From the Timberline crossing it flows north
on the east side of the road beyond Caribou Drive and beyond the
limits (Station 13+67) of this project. Storm drain manholes
exist intermittently along the outfall sewer for access and
maintenance.
The Chandler Sump outfall terminates into an existing
culvert crossing under Timberline on the north side of the vet
clinic. The existing drainage swale, or channel, on the north
side of the clinic flows easterly to other culverts and detention
facilities east of Timberline. The Chandler Sump Outfall
alignment is shown on both the Street Plan and Profile sheets and
the Drainage and Erosion Control sheet of the construction
drawings.
3. The existing detention pond on the east side of Timberline
opposite the Chandler Sump was constructed as a part of the
infrastructure improvements for the Sunstone Village 8th Filing.
The Detention Pond has been partially built and is located within
Tract A, Sunstone 8th Filing. This pond is known as Detention
Pond No. 3 on the Timberline Farm Master Plan (see Exhibit B).
The pond has already been tied into the Chandler Sump
outfall storm sewer. A 15 inch storm drain pipe has been
extended from the bottom of the pond to the most southerly
manhole on the 42 inch outfall storm sewer system, as designed on
the Sunstone plans and supporting drainage study.
Once Timberline is widened adjacent to Sunstone, the final
grading of the pond will be completed. At that time, the other
pond improvements — such as concrete trickle pans, landscaping
improvements, completion of the storm drainage structures and
erosion control measures, etc will be able to be completed.
P,+6,e L -
FINAL STORM DRAINAGE REPORT FOR TIMBERLINE ROAD STREET IMPROVEMENTS
MILESTONE DRIVE TO COUNTRYSIDE ANIMAL HOSPITAL
Widening of Timberline adjacent to the pond will allow
completion of final grading and other improvements in the pond,
but the facility is functional at this time. Straw bales and a
lower area in the pond that acts as a sediment trap protect the
Chandler Sump from receiving significant siltation migration from
the Sunstone pond.
II. PROPOSED STORM DRAINAGE SYSTEM
The east side of Timberline in this reach will be totally
reconstructed and widened. However, the west side will not be
altered as to existing storm drainage conditions. South of
Caribou Drive, the existing pavement will be replaced and minor
modifications to matching existing grades at the westerly
right—of—way line will be made.
North of Caribou, a complete storm drainage system exists
on the west side of Timberline. The pavement reconstruction_
project will not create any changes to the existing system, as
all work will be in the paved area and not in the area of the
existing curb and gutter, sidewalk, inlets, culverts, swales, etc
west of the pavement — the new pavement will match what is there.
Since no changes in storm drainage are being made on the
west side of the street, no subbasins are identified west of the
centerline of Timberline. The proposed storm drainage conditions
for future widening on the west side of the street, including
subbasin characteristics, future curb and gutter flow amounts,
exact inlet location and size and design of the storm drain pipe
into Chandler Sump, grading for sidewalk and utilities, etc. will
be addressed with development plans for those properties west of
Timberline Road.
The following is a description of the storm drainage
conditions that will exist for Timberline Road as a result of
the completion of this street improvement project:
1. The crown of the new road at the new Milestone Drive
intersection will be 15 feet east of its current location. This
is because of the need for Timberline Road's centerline to be
offset by the same amount at Harmony Road — as indicated on the
improvement plans for`Timberline Road south of Milestone.
From Milestone Drive (at Station 45+00) northerly to Station
37+32, the crown transitions from 15 to one (1) foot east of the
current centerline. From that point north, the gutter is 35 feet
east, and the back of a seven foot sidewalk is aproximately 69
feet east of the new crown of the street.
FINAL STORM DRAINAGE REPORT FOR TIMBERLINE ROAD STREET IMPROVEMENTS
MILESTONE DRIVE TO COUNTRYSIDE ANIMAL HOSPITAL
2. Along the entire east side of the project, the area outside
of the new pavement will drain away (downward to the east) from
the back of curb at a slope of 2 percent — rather than a more
conventional 2 percent slope downward from the back of walk
toward the curb and gutter.
This alternate street cross section is being used to lessen
import requirements for fill along the existing low—lying areas
on the east side of the road. More importantly, when the east
side is ultimately widened another 18 feet as planned, the
sidewalk will still be at the proper elevation relative to the
new curb and gutter location.
3. A storm drainage inlet (5 foot Type R) and 50 feet of 24 inch
RCP culvert will be constructed on the east side at Station
35+90, which is the low point of the sag vertical curve. The
inlet and storm drain will collect surface runoff from a small
area of Harmony Road, all of the Timberline Road right—of—way
from Harmony to Milestone, and the paved portion of Timberline
from Milestone to the inlet — and discharge the storm water into
the existing detention pond in Sunstone 8th Filing.
4. From the ridgeline north of Summerstone northerly to Caribou,
storm water runoff from that segment of Timberline Road will
drain around the gutter return in the southeast corner of the
intersection and flow down the south gutter of Caribou to other
detention facilities existing to the east of Timberline.
Although not a part of this construction project, when the
vacant land at the southeast corner of the intersection developes
an additional detention pond will be constructed in accordance
with the Timberline Farm Master Drainage Plan. The pond will be
tied into the Chandler outfall at that time, with little or no
effect on the improvements in this project.
5. From Caribou north to the vet clinic, storm drainage
improvements include a storm drain inlet (5 foot Type R) at
Station 16+80, a storm drain manhole, and 300 feet of 15 inch
storm sewer will be constructed in this project. The new
improvements will carry storm water from this reach of Timberline
to an existing 15 inch storm sewer stubbed out between the
existing curb and sidewalk on south side of the vet clinic
frontage.
A new driveway access is to be provided at Station 18+30 for
the currently vacant Caribou Venture owned property at the
northeast corner of Caribou and Timberline. The driveway will be
falling away from the gutter in Timberline at two percent, so a
relatively small amount of storm runoff will be concentrated and
flow onto the property. Straw bales will be placed behind the
back of right of way to dissipate the small flows onto the
easterly sloping land.
FINAL STORM DRAINAGE REPORT FOR TIMBERLINE ROAD STREET IMPROVEMENTS
MILESTONE DRIVE TO COUNTRYSIDE ANIMAL HOSPITAL
Subbasins for the developed condition of Timberline Road as
a result of this project are identified on Exhibit A to this
report, which is Sheet 9 of 10 of the plans, titled TIMBERLINE
ROAD STORM DRAINAGE AND EROSION CONTROL PLAN. Timberline Road
Subbasins 1, 1-B, 2 and 2-A drain to the pond in Sunstone.
Subbasin 1-A sheet flows onto property belonging to Timberline
Farm, Inc. south of Sunstone 8th Filing.
Subbasins 2-B and 3-A sheet flow onto Timberline Farm,
Inc.'s other parcel north of Sunstone 8th. Subbasins 3 and 4
drain to Caribou and to the east in Caribou. Subbasins 5 and 6
drain to the new inlet on the east side south of the vet clinic.
Subbasins 5-A, 6-A and 7-A sheet flow onto Caribou Venture's
property, and Subbasin 7 flows north in the gutter to the
existing curb and gutter at the south side of the vet clinic.
The proposed drainage plan for Timberline Road has altered
from the anticipated Master Storm Drainage Plan for Timberline
Farm, P.U.D. reported by Engineering Professionals, Inc. When
this office prepared the Sunstone 8th filing drainage plan and
report, some of those modifications were addressed.
The design of this project has led to other minor
modifications to the anticipated storm drainage patterns, but
none that adversely affect existing improvements. Storm runoff
from Timberline Road at Harmony Road (including about 200 feet of
Harmony Road's west bound paved lanes) will not turn easterly at
Milestone as was anticipated at the time of Sunstone 8th plans.
Due to a need to keep the west edge of roadway low to
accomodate driveway acess grades to businesses and homes on that
side, the intersection can not be built up to force those flows
easterly in Milestone. Instead the flows will continue northerly
to the inlet and into the pond in Sunstone.
Also, the master plan had assummed the area east of the new
curb and gutter would flow to the curb and gutter from the
right-of-way line (i.e. back of sidewalk) rather than sheet flow
easterly onto the ajacent properties. Otherwise, the drainage
system is in substantial compliance with the master plan.
As was done for comparing the 8th filing final design
chacteristics versus the master plan, the final design
characteristics resulting from this project are indicated on the
master plan at Exhibit B.
The Hydrologic Characteristics for the sub -basins associated
with this street improvement project filing, as well as for the
combined sub basins at Design Point #'s I and II are included on
the following page as Table 1.
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FINAL STORM DRAINAGE REPORT FOR TIMBERLINE ROAD STREET IMPROVEMENTS
MILESTONE DRIVE TO COUNTRYSIDE ANIMAL HOSPITAL
The Time of Concentrations were determined using the
equation for overland flow in the City design manual, and then by
adding the time of concentrated gutter flow. The time of
concentrated flow was estimated using Figure 3-2 "Estimate of
Average Flow Velocity for Use with the Rational Formula" provided
in the "Urban Hydrology for Small Watersheds" Technical Release
No. 55, USDA, SCS January, 1975.
The formula for overland flow Time of Concentration is:
Tc = C1.87 (1.1 — CCf) D1/23 / S1/3
The subbasins in the Timberline reconstruction and widening
project are relatively small. The maximum time of concentration
for any of the subbasins is just over 16.7 minutes for Subbasin
I. A 10 minute minimum time of concentration was used for the
remaining subbasins, since combined overland and concentrated
flow times were at or less than 10 minutes.
The Time of Concentration for Subbasin 1 is estimated by
assumming minimal overland flow, with 1500 feet of flow
concentrated in the curb and gutter. The flow is estimated at
1.5 feet per second in the 0.4 to 1.0 percent slopes along the
gutter, which equates to a time of concentration of 16.7
minutes.
Time of Concentration for Combined subbasin flows at the two
Design Points is determined using the longest time of
concentration for any of the subbasins contributing at that
point. The longest time of concentration was 16.7 minutes at
Design Point I, which is at the inlet into the detention pond in
Sunstone 8th filing.
III. DESCRIPTION OF STREET FLOWS AND DRAINAGE IMPROVEMENTS
Due to the relatively small area of the subbasins that will
contribute storm runoff from the Timberline Road improvement
project, the concentration of discharges in the street gutters
will be somewhat minor.
The largest flow in a gutter will be from Subbasin 1 as it
approaches the inlet. There a 2 year "minor" design discharge of
3.3 cfs is estimated, and a 100 .year "major" design discharge of
11.2 cfs is estimated. The slope of the street at that location
is 0.4 percent.
According to Figure 4-1 of the design manual and using the
following criteria: Cross Slope of 2 %, so a Reciprocal (Z) of
50; a Roughness Coefficient (n) of 0.016 from Table 4-3, so a
factor of Z/n of 3,125; and an allowable depth of flow in the
gutter of 6 inches dur.ing a two year storm; the theoretical
gutter capacity is 19 cfs. Allowing for design purposes an
actual gutter capacity of fifty percent of theoretical (per
P,4cE
FINAL STORM DRAINAGE REPORT FOR TIMBERLINE ROAD STREET IMPROVEMENTS
MILESTONE DRIVE TO COUNTRYSIDE ANIMAL HOSPITAL
Figure 4-2 of the reference), the gutter will carry about 9.5 cfs
before exceeding City criteria for the two year, or Minor,
storm. 3.3 cfs actual, or 6.6 cfs design, will be 4 inches deep
in the gutter, or 2 inches below allowable.
The allowable capacity for the 100 year storm discharge at
Design Point 1 (the 100 year discharge of 11.2 cfs means that a
design amount of 22.4 cfs with 50 percent reduction factor should
be used) will pond at a depth of less than 7 inches — allowable
is 1.0 feet. Obviously, street gutter flows in Timberline Road
are well within City of Fort Collins criteria. Figures 4-1 and
4-2 for this worst case inlet ponding are shown immediately
following the Vicinity Map at the conclusion of the text.
Storm drainage facilities, or improvements, for Timberline
include cross pans at the intersections of Milestone Drive,
Summerstone Drive and the driveway into Caribou Ventures property
south of the vet clinic. Also they include the inlets and storm
sewers on the east side previously discussed.
The inlet at the low point in the Timberline curb and gutter
that drains into the Sunstone detention pond is to be a 5 foot
Type R inlet. Figure 5-2 of the City Drainage Criteria manual
shows a theoretical capacity to accept storm runoff of 1.2 cfs
per foot of length within the allowable 6 inch depth and 6 inch
heighth of opening for a 2 year storm. A Reduction Factor of 80
percent shows 0.96 cfs per foot actual capacity. The five (5)
foot inlet will accomodate 5 times 0.96, or 4.8 cfs.
This allowable capacity is more than the combined flows of
Subbasins 1 and 2. The 100 year storm discharge for Subbasins 1
and 2 is 14.8 at the inlet. Flows in excess of 7 or 8 inches in
depth during a 100 year storm will overtop the curb and gutter
and weir flow into the detention pond, so the City criteria for
depth of flow is not exceeded during a major event.
At the other 5 foot Type R inlet south of the vet clinic,
Subbasins 5 and 6 contribute a two year storm of 1.6 cfs and a
100 year storm of 5.8 cfs. The approach slope and other capacity
factors are the same, so the inlet is obviously adequate for the
two year storm. The 100 year storm will pond to a depth of only
7 to 8 inches while entering the inlet, which is well below the
15 inches allowed according to City Criteria.
In summary, the proposed storm drainage system and
improvements for the Timberline project is rather minor in scope,
generally consistent with the Master Plan (subject to the
modifications described above), and the resulting storm drainage
system should adequately protect life and property on the site.
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r>
•. TO D[T(AMrM[ DISCHARGI
IN COMPOSITE SECTION:-t
IOLLOW INSTRUCTION S
0
", .. =
ooI
TO OBTAIN DISCHARGE INI�N_-
E1Nj•
SECTION 0 AT ASSUMED
DEPTH > � OBTAIN O. FOR
SLOP( RATIO to AND DEPTH
>' THEN Or • OA .OA
Figure 4-1
NONOGRAPH FOR FLOW IN TRIANGULAR GUTTERS
(From U.S. Dept. of Commerce, Bureau of Public Roads, 1965)
.20 114-
Z
a-
I—
(n. .10
W
a .08
W
W .07
06
0 .0S
co
CC .04
D
V
.03
Q
S
I— a .02
W
IIf
MAY 1984
4-3
DESIGN CRITERIA
tL
I.(
7
O
0
s-06
F=
0.8
N
N
Fs
=0.5
0. 4 %
I
I
�F
=q;C
X
.5
CA
y
I
I
Fo
Z
yff
To
RM
I
I
BELOW
4LLOWABLE
STREET
MINIMUM
GRADE
I
2 4 6 8 10 12 14
SLOPE OF GUTTER (%)
Figure 4-2
REDUCTION FACTOR FOR ALLOWABLE GUTTER CAPACITY
Apply reduction factor for applicable slope to the theoretical gutter capacity to obtain
allowable gutter capacity.
(From: U.S. Dept. of Commerce, Bureau of Public Roads, 1965)
MAY 1984 4-4 DESIGN CRITERIA
THIS FINAL FINAL EROSION CONTROL PLAN REPORT FOR TIMBERLINE ROAD
STREET IMPROVEMENTS (RE —CONSTRUCTION AND WIDENING BETWEEN
MILESTONE DRIVE AND COUNTRYSIDE ANIMAL HOSPITAL) WAS PREPARED BY
BY LAND DEVELOPMENT SERVICES USING THE CITY OF FORT COLLINS
EROSION CONTROL REFERENCE MANUAL for Construction Sites, dated
January, 1991.
The results of this erosion control study are reported in the
enclosed text and supporting documents, and are shown in further
detail on the Utility Plans submitted concurrently with this
report. This report is an update from the original report that
was submitted on October 30, 1994.
Signed this 5th day of January, 1995.
Dennis L. Donovan, P.E.
Land Development Services
309 W. Harmony Road — Unit B
Fort Collins, Colorado 80526
Phone (303) 225-9244
FINAL EROSION CONTROL PLAN REPORT FOR TIMBERLINE ROAD
STREET WIDENING IMPROVEMENTS FROM MILESTONE TO COUNTRYSIDE
NOTE: NORMALLY, AN EROSION CONTROL COST ESTIMATE AND
ACCOMPANYING SECURITY IS REQUIRED. IN THIS CASE THE CITY OF FORT
COLLINS IS BY FAR THE PRIME PARTICIPANT AND BENEFACTOR OF THE
IMPROVEMENTS. SUNSTONE 8TH FILING ALREADY HAS AN ACTIVE SECURITY
DEPOSIT FOR $9,000 THAT WILL NOT BE RELEASED UNTIL THE TIMBERLINE
ROAD AND ASSOCIATED DETENTION POND IMPROVEMENTS ARE COMPLETED.
IN THIS INSTANCE, THE NEED FOR THE EROSION CONTROL COST ESTIMATE
AND ADDITIONAL SECURITY ARE NOT WARRANTED.
General Information:
The erosion control concepts and general design
considerations for the Timberline Road reconstruction project
are outlined in the following paragraphs and shown in further
detail on Exhibit A. The exhibit is the same as for the storm
drainage report, and is Sheet 7 of 10 of the Construction
Drawings titled DRAINAGE & EROSION CONTROL PLAN.
It was determined from the City provided reference manual
and Wind Erodibility Zone Map that the Erodibility Zone for both
Rainfall Erosion and Wind Erosion is moderate for the site.
Standard Form A — "RAINFALL PERFORMANCE STANDARD EVALUATION"
follows this text. It identifies the three areas of concern for
the erosion control plan and identifies their pertinent basin
characteristics.
Subbasins 1 and 2 will drain to the north into a storm drain
inlet on the east side of Timberline. Storm runoff from these
two sub basins will then discharge into the existing detention
facility on the west side of the 8th filing. Both subbasins
will be street pavement.
Subbasins 1—A, 1—B, 2—A and 2—B will sheet flow onto
properties adjacent to the east. The area is the 27 foot of
landscaping and 7 foot of detached side walk.
Subbasins 3, 4, 5, 6 & 7 will flow into the Caribou Drive
for Subbasins 3 and 4, into a new inlet approximated 300 south of
the clinic for 5 and 6, and 7 will flow into the existing curb
and gutter at the clinic. All of the subbasins wii be street
paving.
Subbasins 5—A, 6—A & 7—A will also sheet flow onto property
to the east, and will be the same 34 foot.wide with walk.
Table 5-1 indicates a required Performance Standard of 74.8
percent for the area comprising sub —basins 1 and 2; 78.7 for 3,
4, 5, 6 & 7; and 78.4 for all of 1—A thru 7—A.
Standard Form B "EFFECTIVENESS CALCULATIONS" follows Form A
and identifies the recommended erosion control measures and their
effect on the site.
P,# C,E I
FINAL EROSION CONTROL PLAN REPORT FOR TIMBERLINE ROAD
STREET WIDENING IMPROVEMENTS FROM MILESTONE TO COUNTRYSIDE
Subbasins 1 and 2 include 2.51 acres, of which 2.04 acres
will be hard surface, or concrete and paving. The remaining 0.47
acres will be seeded and mulched, or sodded, as the landscaped
area between the curb and the sidewalk south of Milestone Drive.
The effectiveness is 95 percent.
The area of Subbasins 3 through 7 will be paved and achieves
a performance standard of 98 percent. During construction the
contractor shouldinclude gravel filters for the inlet and provide
hay bales at the back of driveway into Caribou Joint Venture
property.
For subbasins 1—A through 7—A, the area of influence
includes 32.12 acres. Street hard surface (i.e. 7 foot sidewalk
account for 0.50 acres. The remainder of the area is right of
way landscaping and will be seeded and mulched or sodded. The
efficiency rating for this area and the erosion control measures
included is 98.0 percent.
All of the areas easily meet the performance requirements.
During construction, straw bales, silt fence, and sediment basins
shall be used as necessary to protect downstream properties from
sedimentation from storm runoff — in such locations and at such
times as necessary.
To minimize wind erosion from the construction site it is
recommended that the northwest perimeter of the site be provided
barriers of some type. Snow or silt fence, hay bales, windrows
perpendicular to the northwesterly winds would each be a helpful
improvement.
The construction schedule for the project is to begin
grading as soon as the plan approval and weather conditions allow
— say February, 1995. The project will probably be under
construction until June or July of 1994, depending on weather,
traffic and other conditions.
There is very little utility work associated with the
project, so the first work will be in the site preparation for
placement of curb and gutter and widened roadway portion. A lot
of imported material will be required.
The current schedule calls for concrete and paving to be
completed by June, and landscaping should follow quickly. During
construction, adequate watering of haul roads and areas being
graded during construction should also be provided.
Standard Form C Follows Form B to identify the Construction
Schedule and timing for installation of erosion control measures.
The form is included at the end of this report, and on Exhibit B.
The erosion control measures should be maintained by the
City of Fort Collins since it is entirely City owned right of
way.
l�l+G�
RAINFALL PERFORMANCE STANDARD EVALUATION
-=-------------------------------------------------------------------
PROJECT: T i1f BE-RL(NE ROAo lvo RTtt STANDARD FORM A
COMPLETED BY: DATE:
---------------------------------------------------------------------
�DEVELOPEDIERODIBILITY1 Asb I Lsb I Ssb
I Lb I Sb I PS
ISUBBASIN ZONE I (ac) I (ft) I (%) .l(feet) I (%) 1 (%)
2
-------------------------------------------------------I-------
� /l d 1 / 1
1 o er � 2,51 1 6.7 7 iM67-
7�g
NCI 57
79,L�
�77,1
I
3-A1 I l�vclPvafe /,Z�
54,O A+
$7' A i
1 )1356 .
5v
3-q)i i.1 i -7g,-7
�4-7. j I
I
Z, D i 5D 2,0
---------------------------------------------------------------------,
DI/SF-A: LB9
EFFECTIVENESS CALCULATIONS
----------------------------------------------------------------------
PROJECT: TMB£RLIDJZ= �o p li: AILEST6AJr- 2R,STANDARD FORM B
COMPLETED BY: //C_� DATE:
Erosion Control
C-Factor
.P-Factor
Method
Value
Value:....: Comment .
------------------------------------
Po �D.s/V�//}LI;s
D.Q/
-------- ------- =------
I, d
50poR MuLctt
0,06
. ),6
----------------------------------------------------------------------
MAJORI
PS
SUB:
AREA
BASINI
(%)
BASIN
(Ac)
CALCULATIONS
°i.x:z;6* '06X 0.Y1) Z.$l
wTo P = �.d ,' , EFr= 1,t�x 6,col
78:7
3'f�
I
:. F F
DI/SF-B:1989
I
I
i
9
C^::STRCCTICN SErcc!ICE
Tr�tgE,TLr-jc ROAp—%'iLF$TONf nA. r+�?rtl STA!IOARp fCRH C
'ro C- -tJTR� S,oE n1!•�TAL
Rj ONLY CC:I,LETED BY: OAIE: 10-10—S`f REV
in?irate by use cf a tar line or sy^;bols when erosion control measures will be installed.
t:ej^r r_.Iificaticns to an a,proved schedule may require submI tting a new schedule for
a^;r^o:al ty the City Engineer.
YEAR
H-- ----------------
07ERLGi GRADING
WI:lO 'cn-OSIO:I MIMI
5011 Roughing
Ceri,netsr Barrier
Additional Barriers
V•-etative Methods
Soil Sealant
Other
P.AINFALL E"OSION CDIITBOL
tTRUCTU^AL:
Sediment Trap/Basin
Inlet Filters
Straw Barriers
Silt Fence Barriers
Sand Baps
Bare Soil Preparation
G_ntcor Furrows
Terracing
As;!:alt/Concrete Pavir.o
Other
VEGETATIV7:
Permanent Seed Planting
Fivlching/Sealant
Temporary Seed Planting
Sol Installation
liettings/Hats/Blankets
Other
STRUCTURES: INSTALLED BY
VEGETA110:0-11JLCHING CONIUCTOR
4 5
Ccrl�!o.I Ptcl :9-Ax1 rreI IA<RIM4fI7�,!I-TuLIAo6I
- -- ---------------------------------------
MAINTAINED BY
DATE SU2MiTTED APPROVED BY CITY OF FORT CCLLINS CN
NO1/SF-C:1?G?
.. I� I • CARI®ou
i VENr✓RE - J I 1 i �BRI 011'1 t
� !rO swaLE)
I M
DRAINAGE
--� �,/� \\`/ TRACT 1
r werER P H A` \ 2.7 AC.t p
3 I .�suer�ee��e. a. `������
to
1 7
h `
LOTSt = 3� D.U./AC��\ I �\ •+ - ii
2
it TIMBE&L E - \� � / \♦ \� `\ l
I I � ♦ \ ' � 1, I •.,aa'
i r=.we•M,=N .
0.6 n Te7R L \
Or
\
n
�� Q�w•9
j I�•I 13deam
ecr
PHASEHA E
PHASE
J I
OTS± = D.U./AC
l
1�16 AC.f i�� V / �\ 6' a �' ant Fi uNG9 / I / \` `
I• iR 1 1 , C
I `II
1V t .T� SNNS7ouEg �ILING �- I Y� `-
'I-
I I Rer D Sus•skslAl \ \\ \\� � � 1 ! / � / —_�
pp
met Ill
((fVISED`� /.. 1
PARCEL PtROE�G < `�\
-- ~ 2.4 AC.f
oerE.. o•/
sa eePZ%R,,.•ncss
--T-----TiNetRuNE �e DRAINAGE'
ii I I FARM, Two aas ITRACT 2 --
PAR\L` 1.5 AC.t
I - -
i
j' PARCEL 'F' \ ��
L------ BUSINESS -
SERVICES z
HARMONY RG.
w
T GOR O -
)IMBERLINEI`oAD .w LEGEND - - -
' - - •V PAOPOSEPWATEF W/F.k .
•-�---- PROPOSED SA•N/TA" SEWER W/M.K.. -
TIMBERLINEFARM —"— � SMGWA"' —, — ElVET,NG vdN/TART SEIVER
e -- PRA,NAEE SASIN OESIENAT,ON -
V"W AREA
o AOVAOE a QN eauN°ARr AftjNAL. coNCEPT� �-y
MASTER DRAINAGE BOUNDARY /{EVl510 NS FOR FINAL _5 HBERLWE Roles. D4rs/cA!
AND - UTILITY PLAN
HARMONY ROAD
TIMBERLINE DRAINAGE & EROS!ON CONTROL PLAN
HYDROSFGIC CHARAauleRss
TIMMINS ROAD NIMING
Drainage arm c
main (ncise) Valuettilial
Tc3YR TC100YR LSYP
implyin br
LIOOYt
DSYR
0c"tor
5
a31gn
9olnt
1
1.96 0.60
16.7 16d 1.1
5.7
3.3
11.1
u
0.19 0.49
10.0 10.0 1.5
nl
ea
0.6
15
0.31 0.45
10.0 '10.0 1.5
9.1
0.3
1.3
3
0.55 0.95
IDA 10.0 1.5
7.3
1.3
4.0
3A
0.31 0.45
10.0 10.0 3.5
7.3
0.3
1.3
15
- 0.07 -0.e5
10.0 10.0 1.5
7.3
0.1
0.3
3
0.61 0.95
10.0 10.0 3.5
0.1
1.5
bt
3A
0.53 0.46
10.0 10.0 2.5
3.3
0.6
1.1
t
0.11 0.96
10.0 10.0 1.5
7.1
0.3
0.9
5
0.65 0.95
10.0 10.0 1.5
9.1
1.3
4.0
SA
0.49 0.45
10.0 10.0 1.9
3.3
0.6
1.0
5
0.13 0.9s
10.0 10.0 1.5
9.1
0.3
0.9
SA
0.11 0.45
10.0 10.0 1.3
3.1
0e
0.4
1
0.11 0.95
10.0 10.0 1.5
9.1
0.3
0.0
lA
0.11 0.43
10.0 10.0 1.5
3.1
0.1
0.3
C Lm"
flows
tal
1.11 0.83
16.7 16.0 1.1
5.1
Lt
14.5
1
Sae
0.35 0.95
10.0 10.0 3.5
3.1
1.6
5.0
11
MMn
YIWLII: TINfla A NoA0 ,/'/rlaf TeNf ON. 1/s,1n,1
$INYA IpF t
ZaVNTOf .
rl1
MAi
O9MR'L t0• It JE >\
90F 1m tr: VILP
Y.m )o_la_a2
Instant@ 9Y ni II I Lrt Ill or rmmb man mC1m ammal memre ell) M
install".
M30C e•11111•tl@q AN u 4Crn•s install my "Mass "YIRly
a w 14KIa 4r
wren at tM tits "loss
TIM
gf
Ww
Oy1 Nag5kihrq%W AWAnIMrISwITud
AMI
..........................
Yu0 I9•SIM CONTAIN.
Palms,,rummer
V yV
I@Jinenl
API.
Barriers
ve
•attm kA
In
MnMn•nt
MIN1µL EMSM cNIM.
31i
intent T'snaals
blot Filters
Stu SellarsInd
-�
Um S7119 .roam
costly, Twins
TCrt¢Iry
AA t/tmana 9nlry
�rI
at
VEGETATIVE:
Falumnt MN s1uthe
'"story 4el Ilutlq
SN Installation
bltlq✓Mts/lla
Oa•r
-------------
STMNIIE51 11151MLmIT
NIAWRSa
smnATIO A 10 WHIM
. .
Sam NM1nm
MMMm or nn m Im m INS M
M AF-Cum
Erosion control Notes:
1. All disturbed areas are to be seeded
and mulched with permanent grasses.
1. Straw barriers are to installed
at the end of the private driveway
at Station 16+20.
3. The grading operation is to be
monitored by the contractor during
construction for sediment transport
from the construction area.
Additional straw barriers, silt
fence or other measures should be
used as necessary.
Mow
SfA
1' an
60'
1 l
1 OMAOlIGE SISIN NOUHaaRY (lypIUILJ-------_........
nwna
1 II �l 1M
L1_1_Ir
r;
DEGEDGE@ ��,� aGREEMED aI M IMin IMIN It�oe4 -rM rAGGERS@�
son' - V_ y'_ ___--cam=v
r__._ -� I I -lei
is 77
IMIN@ I
\,..
MILESTONE DRIVE
IID1F' . ...
IALL COINTOURS slavlu ANE E31dMND. a. a»snvs/PaoPbssau STDxrn On41A
SEE PAN AND �PRO9EEB SUM Y/Yo>:s105 qHE $Nm:NN ON $✓NS-/Lr/c BTc
r� ` 2INTERSEOTION UE]AIT.b ARE �'"M0. qN0 CNgNOL4q 5✓MP GLANS S
1e y 0.61
sYowN oN x1-°GY 6 a t305T. S1Um1 GRAIN PPE (42"RCP)
r.
1�1 ,�I �1I�1 �A II3�1�1 A�19�A�1�195ai�A9�1 M1 MI ImI�I
,�, I�I�ia�•� �JYpmI)--�-T�_ _ _ �� alwr�l}I
Ii ESE259gM0®E�'IYPERMIET-_ypM�1N LLVlIKK_1- I
VIF
oil
______ .AZ S10I S
_- I"a I'WI I�f
�i �I� 1 / ) I ICI
�' Y
\ _ tor io�' .er p flIWE Pow.p a2t 2-9°'E�A 2 SUMMERSTONE COURT oo] aE2
LN 0.S6
SUNSTONE VILLAGE BTH SUBDIVISION
NO E
8 _ All. (VOK11DURTS EXISTING.
SEE PILAIN!
AND SHREDS fUM
PROPOSED ORIDINO
'►� �� __ OO �._____ __ a-_-
T _ _-=_
r AStrl�lltf•I IAA I�I�I� �•tl�l�l e.
rml�til M 44 IMI�y.=IIIIAIR �I�19�I yj7 �l�
01iSOUNOMY �'�•�Ler:L�i 51�-
aW..n'S4_Au.
1MVIM, �, fE�, a �I A I •♦1 Ate, imi Komi
r'i
II III
°'02 - s >•-A 4 0 CARIBOU DRIVE E-A
0.S1 0M 0.12 O!6 O.Q
LOWE STREET Nola
] NE cONfixts 9101U! ME FNSIOIO.
-- _ oat /'- PMOPOEm OMA0210 SfIFk15' iql
�>•= � -___ am
f
��Gr� '� m--.�. aes,Y llwiwl� �mMP.4 TRER MET fw • start.
y i
5
owI�A�t I I II�Ir �A ICI
1 �^ 1 Nit NM s1mM Iy1M1 I II II
e00 l a s 'f5-o- rs III
___ \�`/ of End of Twee.My I \` i •� aN3¢55asr. llr us slaw wow
%mil -` I
S-A 0 S M `\ \�-�J
EXHIBIT P
DRAINAGE 8 EROSION CONTROL PLAN SHEET NO. 9 OF 10 P-92-193Z
JUNE 20, 1994