FLOOD01207

• Designation Number: 58
• County: Adams
• Community: Unincorporated Adams County
• Stream Name: Second Creek and Third Creek
• Title: Flood Hazard Area Delineation - Second Creek and Third Creek - Adams County
• Date: 2/1/1976
• Designation Date: 3/1/1976
• Floodplain - Doc Type: Floodplain Report/Masterplan

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5

June l5, 1965 - On June 16, 1965, the Brighton Blade
reported that ". . . blinding rain lashed across Adams
County. In Brighton more than one inch of rain fell
in less than two hours." Streams were reported to be
flowing over crop acreage and major irrigation ditches
were reported to be out of their banks. The Wagon
Wheel Roller Rink and other surrounding low lands in
the lower reach of Third Creek were reported to be
covered by 1 to 7 feet of water. In Adams County, no
lives were lost from the extreme flood event, but
property damage was estimated at the time to run in
the millions.

be collected at bridges and culverts and other manmade obstructions.

In addition to the vegetative obstructions, flood waters tend to

erode channel banks and carry the suspended soil material as

well as rocks and boulders further downstream, adding to the debris

and damage at the manmade obstructions. As these masses of debris

accumulate, the artificial barrier soon breaks loose and a wall

May 6-7, 1973 - On Sunday and Monday, floods hit the
Brighton area as a result of heavy spring rains.
Thousands of acres of lowland farm land were covered
with flood waters.

of water and debris surges further downstream to continue the

hazard and destruction.

Examples of the crossings on Second Creek and Third Creek are

No pictures of specific flood damage on Second or Third Creek

shown in Figures 5 through 14. The figures also show the vegeta-

are available. However, Figures land 2 are representative of

tion typical of the channels which tends to obstruct flood flows

flooding which is characteristic of the Second and Third Creek

through reduced channel capacity and structure blockage.

flood plains. The devastation resulting from unwise flood plain

use is shown in Figures 3 and 4.

In general, both natural and manmade obstructions exist which

tend to restrict flood flows and cause overbank or non-channel

- FACTORS AFFECTING FLOOD HAZARD -

flooding. These obstructions will ofttimes result in unpredict-

Factors Which Increase the Flood Hazard

able flood flow patterns. This is particularly true of irrigation

canals crossing natural drainageways. The obstructions also tend

Natural obstructions to flood flow include brush, trees, and

to become sources of debris and further obstruction when struc-

other lowland vegetation which naturally grow along stream banks

tural failure results. Also, manmade flood plain obstructions

and lowlands adjoining drainageways. During periods of high

tend to concentrate flood flows which in turn result in increased

flooding, these obstructions tend to slow the flood velocities

velocities and increased hazards in adjacent flooded areas.

and, as a result, cause greater depths and backwater conditions

that increase flood elevations. Ofttimes the natural vegetation

It is impossible to predict the degree of accumulation of debris

found within the flow area becomes dislodged from its normal

within flood waters and the resulting effect of such accumulation.

location and accumulates as debris within the flood waters to

This report assumed that existing structures within the flood