HomeMy WebLinkAboutLot Certifications - 05/24/1995 (3)117 RE,
MAR - 6 1995 � !
L II
Engineering Consultants
209 S. Meldrum
Fort Collins, Colorado 80521
303/482-5922
FAX: 303/482-6368
March 3, 1995
Mr. Glen Schlueter
City of Fort Collins
Utility Services Stormwater
235 Mathews Street
Fort Collins, Colorado 80522
RE: Centre for_Advanced_Technology-Sixteenth-F-l-i-ng P.U.D..
Drainage Certification
PROJECT NO.: 578-002
Dear Glen:
Attached is a blueline markup showing as -built spot elevations
obtained from RBD survey crews. Some of the spot elevations differ
from what the utility plans call for. The volume for the detention
pond has been recalculated using the as -built elevations and it has
been determined that the 100 year water surface elevation will
raise from the intended 49.13 to 49.21 to obtain the required
volmue of 1.51 ac-ft. The release rate through.the orifice plate
will be 1.93 cfs instead of the intended 1.91.cfs. The area and
curb inlets have been installed as intended as well as the riprap
at the pipe outlet. The orifice plate has been,installed on the
outlet structure as called for on the plans. The hay bales have
been. installed in the bottom of the pond. All paving has been
completed on the site, including the parking lot and Worthington
Circle. The temporary retention pond east of Worthington Circle has
been installed and the volume has been calculated to be 0.32 ac-ft,
which is more than the required volume of 0.26 ac-ft. The pond
areas are to be sodded when the weather allows this to be done, in
the meantime the owner is going to provide the City bond money. It
appears that the constructed improvements will function as
intended.
Thank you for your consideration of this Certification submittal.
Sincerely,
RBD Inc., Engineering Consultants
Tim J./ilev
Design Engineer
Kevin W. Gingery, P.E.
DenvWc5�sources Project Manager
DRAINAGE CERTIFICATION FORM
Please fill out all applicable items in this certification form
for single family, multi' -family and commercial.properties.
Write "OK" for items checked or actual number
checked in field.
Use "N/A" for items that are not applicable to
the property that
is.being certified.
A. Drainage facilities certification
1. Pond Certification
-volume verification
See aJ+-�e_%-eA
a. topographic records and volume
See �++o.e- -eJ
b. cross -sections and spot elevations
See. Q-i"Ee.clld�
-positive.fall to pan
N/A
-side slopes
-invert elevation
_
-spillway elevation
-placement and size -of riprap
O k
-side slopes
o K
-grading
O K
-orifice plate installation and size
6 k
-compaction of berm ye-6-rivoL
-structural integrity of pond
2. Swales
-location (are they within easement) MIA,
-dimensions and cross-section verification
-longitudinal slopes and side slopes N�
-spot elevations
-permanent erosion control measures
(drop structures, riprap, etc....)
-tie-in to pipes, pans, curbs, etc.... N
-weir size (elevations, size, opening, 'etc.-..)
-available freeboard
-landscaping infringement on swales T/-\
3. Pipes
-size and type
-slopes (as -built and comparison to minimum
0.4% slope) 01�
-pipe capacity calculations if slopes are
significantly altered 0 K
-invert elevations 0+�
-installation and backfill material Na 1- V�i-i
-cover k
-encasement and clearance from other utility
lines close by Na
-joints (Je} Vet'i�ed-
4. Concrete Pan Channels
-size
-slope
-super elevation
-cross-section
-thickness
-elevations
S. Inlets
-size and type O K
-size of opening (or name of standard used) Areo
i TV
e e-',r- ` s st+-ell
.-grate elevation
j invert elevation 6
-box size OIr
6. Cross vans
-size
-type Canyr�{e
-grade Olc
-elevation D K
-cross-sectional depth Vo-,r
-tie-in to curb and gutter 0 It-
7. Culverts
-size 15 "
-type _L P
-invert elevation �_39
-headwalls N.
8. Underdrains
-size T
-type
-cover, .
-backfill,,7
-geotextiles 7j�
9. Curb cuts
'iw�E'E cj�i✓`
-size 'Z u3erillr�'(.h
-.tie in to swale, pipe, etc.... k
B. Certification of Grade Elevations Adjacent to
Drainage Facilities:
-minimum opening elevations
-top of foundation elevations
-comparison to 100 year WSEL's
(Freeboard requirements and floodplain issues)
OK
D k
�26Ve WSEL
C. Certification of Erosion Control Measures: �� 1
1. Permanent Measures:
.-Permanent vegetation (6" bare spots and weeds
under control)
-riprap K
.-riprap bedding B1c
-drop sections_
-sediment basins/water quality ponds
-netting mats/blankets N a
-mulching,
2. Temoorary Measures:
-mulching
-inlet filter installation
-check bale dams .
-seeding and temporary vegetation
-silt fence
D. Site Cleanup After Construction
-construction clean up
-smoothing of ruts
-reseeding
E. Statement of Compliance
jn W6t4vkt� �v�-no� �h
O rc
To Le -
41t %
This certification is signed 'and stamped and by signing this
form the engineer(s) attests that to the best of his knowledge
the as -built conditions of the drainage facilities are as
described in the above form and.in the.redlintd plans.enclosed.'
Failure to properly disclose all known information could
result in the rejection of this.certification and prevent the
release of any Stormwater Utility holds on Building Permits
and/or Certificates of Occupancy.
F. Signature.and Stamp by a Colorado Registered Professional
Engineer.
Cinema Savers
014-047
Detention Pond Rating Curve
Cumulative
Elev
Area
Storage
(ft)
(ac)
(ac-ft)
42.4
0.000
0.000 V = d/3*(A+B+(AB)^0.5)
43.0
0.010
0.002
44.0
0.025
0.019
45.0
0.044
0.053
46.0
0.062
0.106
47.0
0.094
0.183
48.0
0.184
0.320
48.5
0.881
0.564
49.0
1.471
1.146
49.5
2.028
2.017
Area-caW.ay core.
0.1
0.08
g 0.06
E 0.04
0.02
0
42 43 44 45 48 47
FIRM
Am I G�
0
T:§D,NC
Engineering Consultants
CLIENT hB.. 5�--uei-S JOB NO. •�1
PROJECT GAT 16'--�- �/ // �{ CALCULATIONS FOR n� L51: c_. (,_U 1 �
MADEBY/tiS DATE��HECKED BY - DATE SHEET OF
Cinema Savers
Retention Pond Rating Curve
Cumulative
Elev
Area
Storage
(ft)
(ac)
(ac-ft)
46.1
0.084
0.000
47.0
0.114
0.089
48.0
0.136
0.214
49.0
0.166
0.364
578-002
V = d/3•(A+B+(AB)V.5)
Ue10 r% v IO�e�- P
= D. 31 G a-c--+
.4 SES '
i
ool
'f•.S _ -
d
TEMPORARY RETENTION HA�IN /I `
r
VOLUME PROVIDED -= 0.26 cc-ft I 1
WSEL = 48.15
AREA=0.15 AC. (d EL. 48.15
FREEBOARD 1.0' \"
y,1 51zz.--
4 AC
\
IEMF'' �� �. c. r. / - EXISTING BASIN LINE
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Z4 lowINLET /go
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