Implementing an Operational Framework to Develop a Streamflow Duration Assessment Method: A Case Study from the Arid...

Area of Science:

• Hydrology
• Ecology
• Geomorphology

Background:

• Streamflow data is essential for water management but often unavailable.
• Rapid Streamflow Duration Assessment Methods (SDAMs) offer a solution by classifying stream reaches using limited data.
• Developing accurate SDAMs is critical for regions with data scarcity, like the Arid West.

Purpose of the Study:

• To evaluate a framework for developing SDAMs.
• To develop a "beta" SDAM for the Arid West United States capable of classifying streamflow duration (perennial, intermittent, ephemeral).
• To identify and test indicators for streamflow duration assessment.

Main Methods:

• Conducted a literature review to identify 41 potential indicators.
• Evaluated indicators based on criteria like defensibility and consistency.
• Measured 21 selected indicators at 89 stream reaches with known flow durations.
• Used analysis of variance and random forest models to select metrics for the SDAM.

Main Results:

• A "beta" SDAM was developed using five biological indicators.
• The SDAM achieved 81% accuracy in distinguishing ephemeral from non-ephemeral reaches.
• Accuracy decreased to 56% when classifying three flow duration classes (ephemeral, intermittent, perennial).

Conclusions:

• The proposed framework is effective for developing SDAMs.
• The "beta" SDAM demonstrates potential for rapid streamflow assessment in the Arid West.
• Further data collection is required to finalize and improve the SDAM's accuracy for multiple classes.