7884

• UCREFRP Catalog Number: 7884
• Author: Hydrosphere Resource Consultants.
• Title: Reconnaissance Evaluation of Yampa River Diversion Structures.
• USFW Year: 1995.
• USFW - Doc Type: Boulder, CO.
• Copyright Material: NO

Mitigation and Modification Alternatives '
Another variation on this diversion type is when the ditch headgate is located on a side
channel which requires a secondary gravel dam. The main channel gravel berm directs flow
toward an island (e.g. at the Deep Cut Ditch) at which point a second gravel berm directs flow
to a headgate or pump. Photographs of the Deep Cut, Cary and Marshall Roberts ditches are
provided in Appendix E.
Permanent Instream Structures ,
This diversion type consists of an instream rock fill dam entirely or almost entirely '
crossing the river. The use of larger rock typically results -in more permanent structures.
These structures may consist of: 1) small (<2 ft.) rock dams with a low section which carries
some low flow but where a large amount of low flow passes through the rock voids (e.g. the K. '
Diamond/Patrick Sweeney Ditch), 2) permanent large rock dams which are stable during high
flows but where the majority of low flow passes through the rock voids (e.g. the Maybell
Canal), or 3) a permanent rock and concrete structure which is stable during high flows and
controls lowflow (e.g. the Craig Water Diversion). Photographs of these structures are
provided in Appendix E.
STRUCTURE MODIFICATION ALTERNATIVES
General Considerations '
A full range of mitigation options exist to reduce or eliminate identified fish passage, ,
habitat disturbance, and watercraft navigation problems at diversion structures. While the
streambank type structures would require little or no modification or mitigation action, the
others might require considerable modification and mitigation. Modification and mitigation
options associated with these latter types fall into the following conceptual categories:
• Do nothing. '
• Convert diversion facilities to a streambank type structure.
• Institute irrigation practice modifications such as: '
a) Closely monitor fish movement activities to facilitate cooperative '
avoidance of impacts (i.e., re-build and maintain structures only when
they are least likely to be problematic);
b) Reduce water needs by changing crop types. '
• Eliminate the need for some or all water diversion by purchasing land and/or water
rights, making payments in lieu of water diversion, retiring land from irrigation,
etc.;
• Implement structural solutions such as: consolidation of diversions (as in the '
Sunbeam and Hayden areas); building permanent cut-off walls with lowflow bypasses
(as was done by the City of Craig); or fully redesigning the diversion arrangements.
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