8283

• UCREFRP Catalog Number: 8283
• Author: Silk, N., J. McDonald and R. Wigington.
• Title: Turning Instream Flow Water Rights Upside Down.
• USFW Year: n.d.
• USFW - Doc Type: Boulder, CO\
• Copyright Material: YES

amount of instream flows to the extent that the reservation for water development can be
maximized or adjusted without exceeding the ecological thresholds of the river's
ecosystem that are supported by the remaining natural flows.

The judgments about the amount of instream flows that should be protected with
appropriative water rights may be no more uncertain than they are for other beneficial
water uses, like irrigation. The amount of an irrigation right is perceived and decreed or
permitted as definite and clearly needed, sometimes down to the hundredths of a cfs. The
connection between the precise increments of an irrigation right and the corresponding
increments of direct benefit to the farm enterprise, however, can be hard to document.
The relation between each increment of irrigation water and the indirect benefits to
society may be no more apparent than for each increment of flow left in the stream for
ecological purposes. Each reflects a societal judgment about the allocation of river flows,
rather than hard scientific or economic facts about the beneficial use of water under state
law. Upside-down instream flow water rights should not be faulted under state law
because the beneficial use of water cannot be documented with greater scientific or
economic certainty than irrigation water rights.

CONCLUSION

Upside-down instream flow water rights should be legally tenable, are just as
quantifiable as conventional instream flow water rights, and should be considered when
seeking to protect complex and not easily predictable natural flow patterns. We offer the
following qualifications to this conclusion based on our review of this kind of instream
flow protection:

. Upside-down instream flow water rights may be most applicable on relatively
undeveloped rivers that do not face severe development pressure. Where streams
are already heavily developed, upside-down instream flow water rights will not
offer protection for low flows during dry periods of the year, but they can protect
peak flows and the dynamics of the stream for the remainder of the year.

. An upside-down instream flow water right can be hedged by combining it with a
conventional instream flow water right. This combination can protect the
instream use of both the bottom and top of the hydro graph, but still leave room for
water development in the middle.

. Upside-down instream flow water rights may work best ifthey are adaptively
managed to err on the side of the river ecosystem. It may be prudent to start out
with a small reservation of water for development that is increased when the
scientific understanding of the natural system indicates that it can absorb more
water development and the need for additional development is certain.

. Upside-down instream flow water rights can only protect the natural environment
if the water reserved for development is not so large that it will undercut the

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