A functional flows approach for developing environmental flow standards in California
Abstract
A California Environmental Flows Framework is being developed to support natural resource managers working to secure environmental flow protections in the state's rivers and streams. The framework relies on a functional flows approach, which focuses on managing elements of the natural flow regime known to support key physical and biological processes that sustain the ecological integrity of rivers. Functional flow components, such as winter floods and spring recession flows, can be quantified by functional flow metrics (FFMs) and predictively modeled to estimate expected natural conditions at gaged and ungaged locations. We describe the development of machine-learning models that use a combination of watershed physical features and time-varying weather data to predict FFMs at reference-quality gages. Model performance is assessed using a leave-one-out cross validation approach. In general, model performance was good for magnitude and timing FFMs, but was less reliable in predicting FFMs describing the frequency and duration of floods. We then describe how the models are used to predict the natural range of variation in FFMs at 140,000 stream segments in the state. Finally, we illustrate how the approach can guide development of environmental flow standards in both highly-altered and less-developed watersheds.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H23N2087G
- Keywords:
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- 0481 Restoration;
- BIOGEOSCIENCES;
- 0483 Riparian systems;
- BIOGEOSCIENCES;
- 1808 Dams;
- HYDROLOGY;
- 1860 Streamflow;
- HYDROLOGY