HomeMy WebLinkAboutLot Certifications - 08/12/2002 (2)STMART$,ASSOCIATES
Consulting Engineers and Surveyors
January 23, 2002
Mr. Jay Barber
Fort Collins Utilities
P.O. Box 580
Dear Jay,
Please find enclosed the redlined "AS BUILT" survey of the grading for Tract A and Lot 1 at
Larks Nest P.D.P
The grading is in substantial compliance with -the flow directions of the approved grading plan
approved by Storm Water Utility on May loth, 2001. The finished floor of the residences is 5073.9. The
garage floor of the residences is 72.4.
Additionally enclosed please find a worksheet with the "AS BUILT" pond contour areas and a
calculated High Water Line required to capture the 100-year flood. The spillway elevation is 5068.65
will fully capture the required detention volume. The restriction plate has been place on the outlet pipe in
a manner that allows for release at the 2-year storm flow rate. The elevation of the grate is 5064.50. The
High Water Line for the required detention plus extended detention storage is within the freeboard of the
pond, whose top is 5069.2 The Water Quality restriction plate has been omitted per my permission. The
pond will function as an extended detention pond and the Water Quality Control Volume will be allowed
to infiltrate and evaporate instead of the restriction plate controlled 40-hour release. All geo-fabric
membranes have been placed in accordance with said grading plan.
All storm water pipes, curb inlets, and area inlets have been placed in accordance with said
grading plan. Please find the invert elevations on the enclosed redlined "AS BUILT" survey. The invert
of the area inlet in the Northeast comer of the project is currently covered with straw bales and dirt and
will be found at a later date.
The grading for Lots 2-6 has not been completed as the buildings are not ready for final grading,
however, the streets and finished floors have been surveyed and are also in substantial compliance with
said grading plan. An additional "AS BUILT" survey of the grading for these lots will be completed at a
later date.
The final grading for Lot 1 and the landscaping for both Lot 1 and Tract A will be completed in
the spring.
If you have any questions regarding this certification, please call.
S RECEIVED R
James H. Stewart and Associates, Inc.
103 S. Meldrum Street • P.O. Box 429 • Ft. Collins, CO 80522
970/482-9331 Fax 970/482-9382 (i� rOZtC2�
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DETENTION POND HIGH WATER LINE
AS BUILT TOTAL REQUIRED DETENTION FOR LARKS NEST PDP
DETENTION: POND HIGH WATER LINE
AS BUILT REQUIRED DETENTION FOR LARKS NEST EXCLUDING EXTENDED DETENTION
VOL. = 1/3 (AREA ABOVE) (DIFFERENCE IN COUNTOUR ELEV.)
2. FOR THE REMAIMDER OF THE VOLUMES BETWEEN CONTOURS (SECTION 9.2)
VOL. = DEPTH/3 (A +(AB) ^.5 + B) FOR: Uniform Sides sec. (9.2)
3. HWL=(VOL.REO.—VOL.LOW CUML)*3/(AREA LOW+AREA HIGH+(Iow area*high area) ^.5)
�� ////77 LEGEND
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2. RELEASE RAZE FROM POND am CFS = TWO YFAR HISTOR/C
3. REQUIRED DETENTION STO210E- 15,226 CF
4. REQUIRED EXTENDED DETENTION - 2, 195 CF
5. TOTAL POND CAPACITY TO ELEVATION 68.50 - 17.423 CF
6. R/M OF AREA INLET ELEVATION - 64.50
7. BORON OF POND ELEVAV0.4 = 63 50
8. RESTRICTION PULE OPENING SIDE - 3.55" x 355" SOLWtE
9. DRILL 1- 5/e INCH HOLE THROUGH SITE- PULE AT ELEI,IOk S
6350; 6382: 64.17, 64.40 FOR 40 NOUR RELEASE RATE
10. 15 FOOT GRASS SPILLWAY ALOW SOUM SIDE OF POND
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S RECE VED R
AUG 0 5 2002
January 23, 2002
Mr. Jay Barber
Fort Collins Utilities
P.O. Box 580
Dear Jay,
Please find enclosed the redlined "AS BUILT" survey of the grading for Tract A and Lot 1 at
Larks Nest P.D.P.
The grading is in substantial compliance with the flow directions of the approved grading plan
approved by Storm Water Utility on May loth, 2001. The finished floor of the residences is 5073.9. The
garage floor of the residences is 72.4.
Additionally enclosed please find a worksheet with the "AS BUILT" pond contour areas and a
calculated High Water Line required to capture the 100-year flood. The spillway elevation is 5068.65
will fully capture the required detention volume. The restriction plate has been place on the outlet pipe in
a manner that allows for release at the 2-year storm flow rate. The elevation of the grate is 5064.50. The
High Water Line for the required detention plus extended detention storage is within the freeboard of the
pond, whose top is 5069.2 The Water Quality restriction plate has been omitted per my permission. The
pond will function as an extended detention pond and the Water Quality Control Volume will be allowed
to infiltrate and evaporate instead of the restriction plate controlled 40-hour release. All geo-fabric
membranes have been placed in accordance with said grading plan.
All storm water pipes, curb inlets, and area inlets have been placed in accordance with said
grading plan. Please find the invert elevations on the enclosed redlined "AS BUILT" survey. The invert
of the area inlet in the Northeast corner of the project is currently covered with straw bales and dirt and
will be found at a later date.
The grading for Lots 2-6 has not been completed as the buildings are not ready for final grading,
however, the streets and finished floors have been surveyed and are also in substantial compliance with
said grading plan. An additional "AS BUILT" survey of the grading for these lots will be completed at a
later date.
The final grading for Lot 1 and the landscaping for both Lot I and Tract A will be completed in
the spring.
If you have any questions regarding this certification, please call.
Sincerely,
Franklin D. Blake, P.E. & L.S.
FDB/mgr
emk
March 18, 2002
Mr. Jay Barber
Fort Collins Utilities
P.O. Box 580
Dear Jay,
Please find enclosed the redlined "AS BUILT" survey of the grading for Lot 2 at Larks Nest
P.D.P.
The grading is in substantial compliance with the flow directions of the approved grading plan
approved by Storm Water Utility on May loth, 2001. The finished floor of the residences is 5073.9. The
garage floors of the residences are 72.3.
The 13' — 8" ads pipe under the sidewalk off the northwest comer of building 2 has been not been
placed according to the original planned and staked grades. The east end is 0.1' low causing the swale
from that end to the 2' curb cut to the east to have a 0.75% grade instead of the planned 1.0%. The west
end of the pipe is 0.4' high, which does not allow adequate drainage to that pipe along swales coming in
from the north and south. If the grades from the south are adjusted to match the existing grades on the
pipe, adequate drainage away from the building is lost at the high point that separates flow to the 13' pipe
in question and flow to the street south of building 2.
If you have any questions regarding this certification, please call.
Sincerely,
Franklin D. Blake, P.E. & L.S.
FDB/mgr
-77 LEGEND
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Z. RELEASE RATE FROM POND 0 90 CFS � TWO YEAR HISTORIC
3 REWIRED DETENTION STORAOE - 15,228 6
' 4 REWNND UIENOEO OETENTIOH = 2.495 CF
5. TOW POND WACKY TO ELEVATION 68.50 - 17.41J CF
6. RIM OF AREA INLET E AMN r 64'10
7. BOTTOM OF PWD ELPMA a 63.W
Sr RESTRICRON P"TE OPENING WE - J.55" N J.55' SIX E
9. GRILL 1- 5/8 WH ROLE THROUGH STEEL Po TN ELEYANONS
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