FLOOD10420

• County: Adams
• County: Broomfield
• County: Weld
• Community: Broomfield, Westminster and Thornton
• Stream Name: Lower Big Dry Creek
• Title: Lower Big Dry Creek Hydrology Study
• Date: 6/1/2005
• Prepared For: Big Dry Creek Watershed Association
• Prepared By: Wright Water Engineers, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Lower Big Dry q;reek Hydrologic Study

Steep cutbanks up to 10 feet high were eJdent downstream of the bridge, with one actively
eroding area abutting a playground in the Thobton subdivision.

During the field visit, a Kerr McGee represJtative was checking the gas tank and indicated that
flood waters had flowed past the berm slounding the tame Access to the tank area was
restricted for about a week during the July flobds.

6.8 Weld County Bridges

Cameron Parrot, P.E., of the Weld County Public Works Project Management Group was
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interviewed by phone to determine whether bridge maintenance along Big Dry Creek had been
excessive. Mr. Parrot reported that three b~dges received maintenance during the summer of
2004 following the large storm events, prim1ari1y in the form of riprap placement along county
road bridge abutments. The county consiJers this type and frequency of maintenance to be
routine (Personal Communication with Came~on Parrot, 2005).

6.9 Oil and Gas Companies

Weld County is Colorado's largest oil producer, representing about 46 percent of annual
Colorado production, and the second highest natural gas producer, representing about 19 percent
of annual Colorado production. Drilling permits nearly doubled between 2000 and 2003 in this
area (Colorado Geological Survey 2003). I Due to the numerous oil and gas wells in the
watershed and their proximity to the creek, one call was made to an oil and gas company to
assess their experiences in the watershed. Halpen Kirkpatrick, excavation manager for Kerr
McGee, indicated that they had experienced many problems related to erosion and flooding along
Big Dry Creek. Mr. Kirkpatrick described Jother location on the Holten property west of 1 52nd
where a bridge had washed out and been reJlaced by Kerr McGee. He also recalled putting the
culverts in on the Chikuma property and inJtalling the bridge at the Rosenbrock property. Mr.
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Kirkpatrick also noted that the well west of Bob Green's property is being shut down, so fhture
repairs to that bridge would be unlikely (pJrsona1 Communication with Ha1pen Kirkpatrick of
Kerr McGee, 2005).

971-179.092
June 2005

W"ght wr' Englnee's, Inc.

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