7912

• UCREFRP Catalog Number: 7912
• Author: Tennant, D. L.
• Title: Instream Flow Regimens for Fish, Wildlife, Recreation and Related Environmental Resources.
• USFW Year: 1975.
• USFW - Doc Type: Billings, MT.
• Copyright Material: NO

(the additional increment necessary to provide 100 cfs). Planners
of water development projects may ask you to justify and apply cost/
benefit ratios for fish to the 100 cfs flow because this makes their
"project purpose" look more favorable on a comparable cost/benefit
basis.

1"

.

5. Stipulate that the downstream flow will not be less than the in-
flow to impmmdments, whenever opera tors of water development proj ects
cannot provide specific flow requirements. Make this an integral part of
every flow regimen recommendation, preferably part of the same sentence.

6. Reduced releases to a stream should not exceed a vertical drop of
6 inches in 6 hours (equal to 2 feet in 24 hours). Fluctuations greater
than this may significantly degrade aquatic resources.

7. Request that maxinn.un flows released from dams not exceed twice

the average flow. Prolonged releases of clear water greater than

this will cause severe bank erosion and degrade the downstream aquatic

envirorunent.

8. Use "undepleted" U.S.G.S. hydrology data for flow recorrmendations
that relate to the stream in its pristine conditions (e.g., before
dams, diversions, pumps,etc.). Otherwise, recorrmendations from the
Montana Method may relate to depleted stream conditions and result
in less than ideal flows.

9. Avoid recorrmending minimum instantaneous stream flow regimens less
than 10% of the average flow since they will result in catastrophic
degradation to fish and wildlife resources and harm both the aquatic

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