FLOOD05761

• Designation Number: 211
• County: Larimer
• Community: Fort Collins
• Stream Name: West Vine Drainage Basin
• Basin: South Platte
• Title: Major Drainageway Planning - West Vine Drainage Basin
• Date: 12/1/1980
• Designation Date: 3/1/1983
• Floodplain - Doc Type: Floodplain Report/Masterplan

VI, DAMAGE ASSESSMENT

In gener~l, the assessment of flood damages in the West Vine
Basin followed the procedure outlined by Grigg, Botham,
Rice, Shoemaker" Tuckerf9l This procedure consists of the
following steps:
1. Policy deci5i.on establishing the baseline condition
2. Division of study area into appropriate reaches
3. Selection of likely damage categories
4, Procurement or development of depth-damage
relationships for these damage categories
5. Computation of the baseline annual damages
This section addresses these steps as they apply to this report.

VI,A,

Baseline Condition

The Technical committee has selected the hydrology of the
fully developed basin and the existing develooment of the
floodplain as the baseline condition against Which to calculate
potential damage reduction. In examining this condition,
any approved but undev~loped Hubdivi~ions located in the
floodplain were considered as existinq, This is the commonly
"ccepteJ b"seline condilion In dLe<<s or C:oloLddo that nave
effective floodplain regul"tions.

VI,B.

Reach Delineation

In the damage assessnent and eeoDomic analysis phases of the
study, the basin WilS div ided into elev"n r€o.ches. (See Figure 17,
Paqe 58) The reaches were delineated for damaGe Rssessmen~ b~spd ~n
one or more of the following reasons: 1) similar development densities
throughout reach; 2) similar effects resulting from major
drain<lgeway improvements; 3) similar unimproved flow character-
istics and/or 4) computational convenience. Since the basin
is divided for different re<lsons for damage assessment than
for hydra~lic computations, it is natural to expect the divi.sions
will be different. A reach or decision unit for damage calcu-
lations may consist of several hydraulic reaches, or may be

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only a portion of a hydraulic reach, The divisions used
for damage calculations are:
poudre River to the Colorado ~ Southern Railroad
The ColoradO & Southern Railroad to Vine Drive
Vine DriVE' to the Vine Drive Subdivision
The Vine DrivE' Subdivision, also referred to as
Frey to 8ry"n,
The undeveloped area in the northwest quarter of
Section 10 referred to as Frey to Taft
The south fork of the basin from Taft Hill to
LaPorte Avenue
poudre High School administration and maintenance
buildings
The reach from poudre High School irrigation pond
to Overland Trail
The north fork of the basin from Taft Hill to
the New Mercer Canal
10, Irish Green Subdivision
11. The reach from Irish Green Subdivision through
the natural detention pond west of Hollywood
Street refez;red to "'"s Hollywood to Sl.'nsct

1.
7,
3,
4 ,
5,
6,
7 ,
8,
,
9,

VI,C,

DamaGe Cateqories

The deter~ination of damage categories actually involved two
steps in one. First, a broad list of possible damage categories
was developed. Then the list was evaluated and unlikely
c:ltcgories discarded. Dal'lUges such as clean-up cost, loss of
rentals, missed work, inconvenience, and tenant relocation
costs were dealt with as indirect damages and estimated as a
percentage of direct damages as suggested by Grigg, Botham,
Rice, Shoemaker & Tucker!9) The full decision process involved
in this step is set out i.n Table 5 clnd cliscussc>d briefly below.

The two nKlst frequent causes of "'limination of categories were
the absence of :l specific land use from the flood~lain ~nd
sufficiently slow and shallOW flows as to cause insignificant
damages. Commercial land uses such as retail and whOlesale

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