FLOOD02248

• County: Clear Creek
• Community: Georgetown
• Stream Name: Clear Creek
• Basin: South Platte
• Title: Flood Hazard Mitigation Report
• Date: 9/1/1998
• Prepared For: Georgetown
• Prepared By: Montgomery Watson
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

Often these residences have encroached into the historic channel with concrete, rock or wood
retaining- walls and the channel has, as a result, been confined to a narrow corridor through most
of town. This narrowing and straightening of the creek channel has reduced its flood carrying
capacity and exacerbated flooding problems. The number and proximity of low-lying homes has
created the possibility for significant property damage. Finally, the lack of existing right-of-way
and physical space for construction severely limits options for flood control.

An additional factor influencing the selection of flood control alternatives is the historic
character of the town. Established in 1868 on the strength of local mining activities, Georgetown
has been declared a Historic Landmark as part of the Georgetown-Silver Plume National Historic
Landmark District and contains nUmerous buildings on the National Historic Register. The
restored downtown area, centered on 6th Street, is a summer tourist attraction. Residents of the
town and other citizens with an interest in historic preservation will be especially sensitive to the
aesthetic qualities of proposed flood control projects. This fact has been taken into consideration
in the evaluation of alternatives.

TABLE 4-1
EXISTING HYDROLOGY AND HYDRAULICS
FOR GEORGETOWN FLOODING SOURCES
Existing Existing
10- Y r 25-Yr 50- Yr 100- Y r Limiting Protection
Flooding Source Reach Flow Flow Flow Flow Capacity Level
(cfs) (cfs) (cfs) (cfs) (cfs) (years)
Upper Clear Creek (I) 600 730 830 910 730 25
Lower Clear Creek (2) 980 1190 1330 1480 630 <10
South Clear Creek 420 520 580 640 275 <10

Of the 88 structures located in the 100-year floodplain, 69 are single family residences, 7 are
multi-family residences, and 12 are commercial buildings (restaurants, hotels) and public
buildings such as churches. No critical facilities such as police stations, fire stations, or schools
are located in the mapped 100-year floodplain. The portion of the Clear Creek floodplain
immediately upstream of Georgetown Lake is of interest to the Town as a future recreational trail
corridor connecting the Lake with the historic downtown area.

(I)
(2)

Upstream of South Clear Creek confluence
Downstream of South Clear Creek confluence

TABLE 4-2

4.5

PROBLEM STATEMENT

RECURRENCE INTERVAL OF RECENT FLOODING EVENTS
IN GEORGETOWN, COLORADO

a.

The 100-year flood on Clear Creek and South Clear Creek affects 76 homes and 12
commercial and public buildings in the Town of Georgetown. Many are historic
buildings built right on the channels.

Year of Flooding

Approximate Recurrence
Interval
(years)

b.

Repetitive flooding on South Clear Creek (four times in the past 30 years) threatens 17
homes with inundation, affects many other buildings with basement flooding, and results
in road closures. However, there are no repetitive loss structures, as identified by FEMA,
located in Georgetown.

1995

10

1984

<10

c.

. No critical facilities are located within the 100-year flood area.

1983

<10

d.

Traditional flood control solutions as well as many nonstructural alternatives are difficult
to apply in Georgetown due to the historic character of the affected properties.

1965

70

e. The Town does not currently own or control maintenance of channel banks where past
improvements (floodwalls and cribbing) have been constructed.

f. Many structures are impacted by high groundwater associated with heavy spring runoff.

4-3

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