FLOOD00835

• County: Statewide
• Community: State of Colorado
• Title: Comprehensive Flood Plain Studies Using Spatial Data Management Techniques - Corps - Technical Paper No 47
• Date: 1/1/2001
• Prepared For: State of Colorado
• Prepared By: Hydrologic Engineering Center
• Floodplain - Doc Type: Educational/Technical/Reference Information

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and developing similar data for categories without structures such as for the category
developed open space. The composite damage function for the agricultural category was
generalized to represent an agricultural enterprise in that the function considered a typical
mix of farm structures, crops, farm machinery, livestock, etc.

TABLE 3. HydIologic Data Summary, Trail Creek.

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I DO-YEAR PEAK FLOW AND ELEV ATlON

Index
Station

Existing Land Use
Flow (cCs) Elevation

1990 Land Use
Flow (cCs) Elevation

I
2
3
4
5

7600 627.1 9400 628.3
3450 656.4 3800 656.7
2600 711.9 2900 712.2
3900 650.3 5]00 651.2
1600 694.2 1650 694.3

FLOW-EXCEEDANCE INTERVAL DATA
(cfs)
Index Station
Exceedance I 2 3 4 5
In_aI (yr) Exist 1900 Exist 1990 Exist 1990 Exist 1990 Exist 1990
5 2000 2800 950 ]200 800 960 1100 1700 500 570
10 3000 3900 1350 1650 1100 1300 1600 2300 700 780
25 4400 5600 2000 2400 1600 1850 2300 3300 1000 1100
50 5800 7300 2650 3000 2100 2350 3000 4000 1250 1350
100 7600 9400 3400 3800 2700 3000 4000 5200 1600 1700

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The composite damage function data is prepared by land use category and the
DAMCAL program then accesses the grid data me and computes elevation-damage rela-
tions for the land use categories and damage reaches. The damage function aggregation
for future land use can be accomplished so that a1l designated new land use (change from
existing) will be placed no lower than a prescribed policy elevation, such as the existing
100-year flood level, and development control policy, such as flood proofing to the
ground floor will be accounted for. Alternative land use control policies can thus be
easily and quickly evaluated.
Table 4 summarizes selected expected arumal damage assessments for a range of condi-
tions and land use control policy sets for damage reaches within the Trail Creek watershed
that sustain significant damages.
The results are somewhat surprising and at first glance may be difficult to understand.
An initial reaction might be that evaluation condition CODE IV should be similar to

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