FLOOD08945

• County: Larimer
• Community: Fort Collins
• Stream Name: Dry Creek
• Basin: South Platte
• Title: Hydrologic Analysis Major Drainageway Planning Dry Creek
• Date: 7/1/1979
• Prepared For: Larimer County
• Prepared By: Gingery Associates, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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residential development, and commercial development continues to ex-
pand along College Avenue. Residential development is also expected
in areas immediately north of U.S. Highway 287, extending as far as
six miles up the basin. Above this area, the basin should remain in
agricultural use in the foreseeable future.
As the basin develops, increased local drainage will lead to
larger and more frequent flows along the Dry Creek channel. This
will cause flooding problems in areas where the old Dry Creek channel
no longer exists, and will lead to increased prOblems of channel
maintenance.

Basin Flood History. Recent history has shown that no serious flooding
has occurred in the Dry Creek Basin below Eaton Ditch in the last 25 to
30 years. This absence of even minor flooding is generally attributed
to the network of irrigation canals that have some capacity for inter-
cepting Dry Creek flows.
Flood history prior to this time period is a little less clear.
Before substantial development occurred in the area, flows could
often be ignored or overlooked where little damage is incurred.
Flooding did occur in the Dry Creek basin in 1924 with flows several
feet deep at the present location of Jax Surplus; however, it is
unclear as to whether this was actually due to overflows from the
poudre River.
Presently, the impact of new development in the lower basin is
already being realized. New developers, who in the past had disposed
of drainage flows by discharging into irrigation canals, are being
denied by the irrigation companies. The irrigation companies realize
the impact of subdivision development on drainage and the impact on
their canal systems.

- STUDY RECONNAISSANCE -

Initial Meetings. The Dry Creek Basin is an extremely complex hydro-
logic drainage basin which required a more than normal amount of ini-
tial reconnaissance. The irrigation canals and reservoirs contribute
greatly to this complexity, and initial meetings were held with the
major irrigation companies to review operation of their systems.
Meetings were held separately with the Eaton Ditch Company, the
Water Supply and Storage Company, and the North Poudre Irrigation Com-
pany. All ditch companies showed an awareness of the impact of their

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