FLOOD02803

• County: Weld
• Community: Windsor, Laku Landing
• Stream Name: Cache La Poudre River
• Basin: South Platte
• Title: HEC-2 Study of Laku Landing
• Date: 2/4/1992
• Prepared For: Laku Landing
• Prepared By: CWCB
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Summary of Results

15

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Figure L5. Construction Conditions at Cross Section 145760

construction conditions, Cross section #145760 (one cross section upstream of Laku Landing) and
cross section #148950 (three cross sections upstream of Laku) realized a drop in water levels of
0.3 feet and 0.1 feet, respectively. The water levels were not increased anywhere mostly because of
(a) more accurate topography information from field surveys and (b) an increased velocity of 0.2
feet per second at noss section #145760. The only other change to the reach of the study was the
velocity decreased at cross section #147200 by 0.1 feet per second.

Now that the hydraulic analysis has been discussed, we must address the pertinent FEMA and
Weld County regulations concerning flood plain and floodway development. In doing so we must
consider two different flood plain zones and the limitations of development within each zone:

1. Flood plain area inside of an adopted flood way. Any development within this zone must not
create any rise in the water surface level of a base flood discharge.

2. Flood plain area where there is no adopted flood way. Any development in this zone, when
considered with all planned future development, must not create a rise in the water surface
level of a base flood discharge of more than one foot.

The East half of Laku Landing falls into zone (1); flood plain area inside of an adopted flood way.
As shown in the hydraulic analysis of this document, the end project as well as any construction
conditions will not create a.ny rise in the water surface level of a base flood discharge.

The West half of Laku Landing falls into zone (2); flood plain area where there is no adopted
flood way. Although FEMA regulations allow for up to a one foot increase in the water surface of
a base flood discharge, and Weld County regulations have no such restriction, the effect of the end
project as well as any construction conditions at Laku Landing results in no increase of these water