FLOOD10473

• County: Gunnison
• Stream Name: Crystal River
• Basin: Gunnison
• Title: Crystal River Study Correspondence
• Date: 6/25/2004
• Floodplain - Doc Type: Correspondence

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ENGINEERING, INC 5100 S Akron street, Suite 300, Englewood, CO 501lc. Phone (303) ccl-0502: II=al{ (303) c2:I.4019

Planning

June 26, 2003

Mr. Tom Browning
Colorado Water Conservation Board
1313 Sherman Street, Suite 721
Denver, CO 80203

RE: Proposal For Engineering Services - Crystal River Floodplain

1anagement Dear Tom:

Thank you for considering ICON Engineering for the above referenced project. We are
very interested in working with you and Gunnison County on completing this study. Our
proposal is based on your request for the proposal dated May 28, 2003, our subsequent
meeting on May 29, and a field reconnaissance completed on June 19, 2003. It is our
understanding that the study reach is along the mainstem of the Crystal River extending
from the confluence with Lost Trail Creek (upstream of the town of Marble) and
extending downstream to the Gunnison County Road 3 crossing near the US Forest
Service Boundary.

With your help, we obtained digital files of the base mapping from Kucera West, and
have loaded the data into our computer system. It appears that the mapping starts just
downstream of the confluence with Lost Trail Creek. Approximately 600 feet of ,
mapping will need to be extended upstream in order to catch the confluence area, or there
will have to be a revision to the study limits. In looking at the mapping, we have located
four bridges/culverts qrossing the study reach. It is apparent that much of the re:ach
within the Town of Marble is in marshes and wetlands. It appears that the Bear Lake is
off-channel, but in close proximity to the river. Based on our conversation, it was
decided that Bear Lake, will not have a significant impact on the flood hydrology and will
not be considered for d~tention storage in either the hydrologic or hydraulic evaluations.

We completed a brief:f;ield reconnaissance of the study area and found that the upstream-
most bridge crossing (near Bear Lake) is on private property that is protected by a locked
gate. In order to model the bridge, we will need access to that' area when we are
completing our field survey. At this time, we are assuming that the County or Town will
contact the property owner and arrange for us to gain access to the bridge.

In reviewing the information transmitted to us, we have not been able to locate the field
control used for developing the mapping. For the purposes of this proposal, we are
assuming that the CWCB will be able to provide us with this data, so we can complete