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larimer-weld regional planning commission
SFECIFICATIOUS FCR A CCST PRGPCSAL FCR THE CACHE LA FCUDRE RIVER
FLCOD PLAIN STUDY
Part I . General Description of the Proposed Study.
The Larimer-'geld Regional Planning Commission reouests a cost
proposal for a Flood Plain Study of the Cache La Foudre River from
La Port to the confluence of the South Platte River . The study will
define the 50, 75 and 100 year flood plain.
The study will be conducted in two phases . Phase I will con-
sist of field control , mapping and cross section tabulation con-
ducted by a firm or agency. Phase II will he composed of a flood
plain delineation done by the U. S. Army Corps of En.^:.nc3rs .
Herinafter, the bari_ner-Weld Regional Planning Corm .ssion
(which includes the counties, cities , and towns in Larmier and
Leld Counties) will he referred to as the "Cornission." . Also,
the firm or aeency which will be contracted to conduct Phase I
will be referred to as the "Contractor .
Fart II . Phase Field Investigation and '. apning by the Contractor .
A. Section Con:era7. Conditins
I . Scope of or.k : •
The Contractor shall perform all work and
POST OFFICE BOX 2137/ FORT COLLINS, COLORADO 80521 /484-13O3
710550
Flood Flain Specifications Page 2
1. Scope of Work : (Can' t) ,
f irnish all services, eouipment, supplies , per-
sonnel, plant, transporation, and all aerial
photo flights necessary to furnish the aerial
photography, topographic mapping, and cross sec-
tion tabulation specified herein.
The work specified herein shall be completed
by priority. Moreover, the work must meet with
the approval of the Commission before the Corn-
mission will consider that the terms of the
contract have been fulfilled .
2. Priorities :
a . FIRST: Canyon mouth to the confluence
of Spring Creek.
b . SECCMD : Sheep' s Draw to the confluence
of the Platte.
c . THIRD : The remainder of Lariner County
and Weld County to Sheep' s Draw.
3. I.iaterials to be furnished by the Ccrtractor .
to the Cc m scion :
a . Tflnonraohic ".anpino :
Co;ipcs4 e Film positive of the
topographic information on a photo-
graphic base with the following al-
ternates :
Flood Plain Specification Page 3
1 . ) Alternate #1: Priorities 1, 2
& C with a scale of 1" - 200' and a
contour interval of 4 feet. (If this
alternate is chosen by the Commission,
aerial photographs will be available
from the Corps at a scale of 1 : 12, 000) .
2. ) Alternate #2: Priorities 1, 2
with a scale of 1 - 100' and a con-
tour interval of 2 feet . Priority 3
with a scale of 1" - 200' and a con-
tour interval of it feet . (If this
alternative is chosen by the Com-
mission, aerial photos must be re-
flown) .
b. Cross-Section Information
The Contractor shall submit the cross
sectional information in tabular form
( approximately 200 cross-sections) .
c . Cross-Section Cverla
The Contractor will submit an (overlay
of the topographic map showing cross-section
location and alignment with location of
zero station for each cross-section.
4 . Licencs and Permits :
a . The Contractor will obtain all necessary
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Flood Plain Specification Page 4
4 . Licences and Permits : (Cont . )
permits and approvals from all local,
state and federal authorities .
• b . Should it become necessary in the
performance of the work for the Con-
• tractor to secure right of ingress or
egress to perform any of the work on
properties not owned or controlled by
the Commission, the Contractor shall,
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if practicable, secure the consent of
the owner, his representative or agent
prior to effecting entry on such property.
5. Responsibility:
The Contractor shall be responsible for
all damages to persons and property which occur
as a result of work performed by the Contractor
in the prosecution of the contract .
6. Safe Operation:
The Contractor shall conduct the .cork with
due 'reaard to safety and shall maintain safe
working conditions at the site of the work .
7 . Topooraphic Conditions .
The Contractor is charged with making his
own reconnaissance and estimate of the character
of the terrain with regard to difficulties in-
volved .
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Flood Plain Specification - Page 5
8 . Report of Progress .
The Contractor will be required to forward a
weekly report of progress to the Commission. The
report is to contain a listing of completed work
as well as a statement of work in progress and an
estimate on percentage basis of over-all completion.
B. Section 3: Special Conditions
1. Special Conditions by Alternates:
•
a . If Alernate 41 or Alternate 42 is selected :
1 . Contour Limits
The limits of the contours shall be
at an elevation of twenty (20) feet above
the surface of the river at the time of the
aerial flights regardless of the distance
necessary to attain that contour.
b . If Alternate ;tl is selected :
1 . Scale of F'h:otooraphv, (Scale of 1" - 200' )
The Cache La Poudre River shall have a
• scale of 1 : 12, 000.
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Flood Plain Specification Page 6
c. If Alternate # 2 is selected :
1 . Aerial. Photographs.
a . If Alternate 2 is selected , the aerial
photography shall be exposed with a calib-
rated precision Aerial Camera equipped with
a high resolution, distortion free lens .
b. The exposures shall cover the area stere-
copically and at the proper scales to provide
for the contour intervals and accuracies
specified herein .
c . Scale of 1" - 200'
The Cache La Poudre River shall have a
scale of 1 : 12,000.
d . All negatives and two (2) sets of contact
prints , on double-weight semi-matte paper,
of the River photography.
e. Photo Index: Furnish all negatives and
two (2) sets of contact prints of the Cache
La Poudre River photo indexes .
use of �.irfie_ 's : (If Alternate 2 is Selected ) .
The Contractor will be responsible for
making all arrangements fcr use of airports ,
airfields , or emergency landing fields . Such
arrangements by the Contractor will be made
without obligation on the part of the Com-
mission.
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Flood Plain Specification rage 7
2. Control.
a. Horizontal and Vertical Control Surveys .
1. The Control surveys required for all
mapping specified under this contract shall
be performed by the Contractor.
2. The density, location, and methods used
to establish control shall coincide with
the photogrammetric procedures, scale,
contour interval, and plotting instruments
used.
b. Accuracy of Surveys.
1. Horizontal. Basic horizontal instru-
mental surveys shall meet the requirements
for third order traverse; i . e. , the error
in closure before adjustment shall not exceed
one part in 5, 000.
2. Vertical. Basic vertical survey acc-
uracy shall meet the recuirments for third
order leveling.
3. Topographic Maps - Cache La roudre Area .
a. Scale. The final publication scale of the
mapping is described under Part II, Section A.
3. L.. ,
b. Contour Interval. The contour interval of
the mapping described under Part II, Section A.
3. C. .
Flood Plain Specification Fage
4 . Vertical and Horizontal Control Accuracy.
a . Horizontal Accuracy.
The horizontal accuracy is to be such that
not more than 10 percent of the points tested
Mg
shall be in error by more than ."1"744Q� an inch
measured on the publication scale. These limits
of accuracy shall apply in all cases to the
positions of well-defined points only. "Well-
defined" points are those that are easily
visible or recoverable on the ground , such as
the following : - monuments or markers as bench
marks, property boundary monuments, corners of
buildings or sturctures . In general, what is
"well-defined" will also be determined by
what is plottable on the scale of the map
within 1/100 of an inch.
b . Vertical Accuracy.
Vertical accuracy shall be such that not
more than 10 percent of the elevations tested
shall be in error more than one-:Zalf of the
contour interval. In checking elevations taken
from the map, the apparent vertical error may
be decreased by assuming a horizontal displace-
ment within the permissible horizontal error for
the map scale.
Flood Plain Specification Page 9
5. Monuments .
a . Vertical Position.
The elevations of the nonuments .shall be
run with third order accuracy, and the elevation
shall be with reference to :.,ean Sea Level .
C. Section C : Completion Deadlines :
These items shall be completed by the Contractor and
submitted to the Ccmi_ssion by the following dates :
1. Priority 1 - 29 February 1972
2. Priority 2 - 31 :. arch 1972
3. Priority 3 - 30 April 1972
Tart III . F tease IT : Flood Plain Delineation.
The Corps of Engineers in Crr.aha, Nebraska will delineate
the Cache La Poudre flood plain from data submitted by the
ontractor.
Part IV. Sii'rni ttal Procedure fn Cost Pron^sals.
a . Cc st estimates should be submitted to Edward S. :telly,
Actin° Director of Public .arks, City of Greeley.
b . Cnst proposals are issued this date and must ce submitted
no later than .1 F .1:, ;.'.ST, December 17 , 1971 .
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Flood Plain Specification Page 10
Issued By:
The Larimer-Weld Regional Flood Plain Study Selection
and Recommendation Committee.
• Members:
Mr. Roy A. Bingman, City Engineer, City of Fort Collins .
' Mr. Edward S. Kelly, Acting Director of Public Works,
City of Greeley.
Mr. Dwight Whitney, Planning Director, Larimer County.
December 6 , 1971
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