Flows and Transport in Rivers - Hydro-Environmental Analysis: Freshwater Environments - page 123

Acreman et al. (2003) write that DRIFT has four modules: (1) biophysical, (2) socioeconomic,
(3) scenario building, and (4) economics. Modules may be omitted according to the available com-
mon properties of scenarios. The biophysical component consists of irst analyzing low data to
develop hydrologic statistics, such as seasonal lows and the number of days in seasons; seasonal
low duration curves; the magnitude, volume, and duration of high lows; and other statistics. The
low characteristics are then linked to cross-sectional characteristics. Scenarios are developed and
incorporated into the database in the form of consequences due to additional possible low regimes
or subtle variations in the EFRs (King et al. 2008). For scenarios, the biotic and socioeconomic
responses are then compiled and incorporated so that each scenario includes a modiied low regime,
the resulting river condition, likely social and economic impacts, as well as the costs of mitigation
and/or compensation for negative impacts. The DRIFT database can then be used to set lows for
achieving speciic objectives by incorporating a DRIFT solver. The DRIFT solver creates scenarios
and an ultimate severity and integrity rating that describes the distribution of lows that would result
in the best condition of the river ecosystem (Acreman et al. 2003).

4.6.2.4.4 Nature Conservancy's Collaborative and Adaptive Process
for Developing Environmental Flow Recommendations
Another example of a method based on expert panel consensus is the Nature Conservancy's col-
laborative and adaptive process for developing environmental low recommendations (Richter et al.
2006). The process includes ive steps:

• An orientation meeting to inform and engage stakeholders.

• The selection of an institution or agency and the development of a literature review and

a summary report on existing knowledge about low-dependent biota and ecological pro-
cesses of concern in order to identify key aspects of low regimes important to the sustain-
able health of the system. Richter et al. (2006) deine key questions to be addressed in the
summary report.

• A workshop to develop ecological objectives and initial low recommendations, and to

identify key information gaps.

• The implementation of the low recommendations on a trial basis to test hypotheses and

reduce uncertainties.

• The monitoring of the system's response and conducting further research as warranted.

The last three steps are intended to be iterative and part of an adaptive management process.

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