FLOOD01374

• Designation Number: 521
• County: Weld
• Community: Erie, Firestone, Dacono
• Stream Name: Tri-town drainageway, Godding Hollow Basin
• Title: South Weld I-25 Corridor Master Drainage Plan
• Date: 9/8/1999
• Prepared For: Weld County
• Prepared By: Anderson Consulting Engineers, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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All the quadrangles utilized the NAD29 Vertical Datum and incorporated a contour interval of 10
feet.

In addition to the USGS mapping, digital aerial photographic images (l998) were obtained
from Weld County and utilized to illustrate the location of all proposed improvements.
The survey data necessary to complete the project was provided by TST, Inc. of Fort
Collins', Colorado. ,

1.5 Previous Studies

Previous studies related to stormwater management within the Godding Hollow and Tri-
Town Basins were collected and reviewed during the completion of this project. No reports for
the Godding Hollow Basin were identified through the research effort; however, several reports
for the Tri- Town Basin were identified.
Reports documenting stormwater drainage conditions and improvements in the Tri-Town
Basin included:

(a) Preliminary Engineering Report Drainage Study Firestone-Frederick Area (Nelson,
Haley, Patterson and Quirk, Inc" September 1975);

(b) Master Drainage Study For the Tri-Area Basin, Including the Towns of Frederick,
Firestone and Unincorporated Evanston (Rocky Mountain Consultants, Inc"
September 1984);

(c) Report of Investigation for the Tri-Area Drainageway Improvements, Town of
Firestone (TST, Inc, , November 18, 1991); and

'(d) Conceptual Design Report For South Side Drainage Improvements, Town of
Frederick, Colorado (Rocky Mountain Consultants, Inc" April 1996).

Several other drainage studies associated with development within the basins were also collected
and reviewed, The information gathered from these reports, including the available design
drawings and specifications, were evaluated and utilized during the completion of this master
planning effort.
With respect to flood studies within the basins, the Federal Emergency Management
Agency (FEMA) has produced approximate flood information and mapping along the Saint Vrain
River and Godding Hollow. Furthermore, FEMA has documented flooding in the Tri-Town Basin
in the following documents:

T:IOPEMCoweldOl\cowe/.dOI jn1 rpt. wpd

1.5

September 8, 1999