Upstream Tech presents statewide reach-scale daily historical flow datasets to CEF work group

Upstream Tech presented new statewide reach-scale daily flow datasets to the California Environmental Flows Work Group during a virtual meeting, describing two products: daily unimpaired-flow predictions and daily actual-flow predictions covering about 20 years at reach scale on NHDPlus flow-lines.

The datasets — one intended to represent natural (unimpaired) flows and one representing observed/managed (actual) flows — were trained using machine-learning approaches and validated against held-out gauges in California, presenters said. Mustafa Alkurdy, a machine-learning modeling engineer at Upstream Tech, said the project produced reach-scale predictions on thousands of NHD flow-line segments and that the team downscaled subbasin predictions to reach-level outputs.

Why it matters: Managers, researchers and practitioners told the group the new products should help fill observational gaps where gauges are missing, support applications such as functional-flow calculations and inform planning for restoration, reservoir operations and water-allocation studies.

How the datasets were produced and validated Upstream Tech described a multi-step approach: (1) train base models on many gauged sites to learn basic hydrologic behavior; (2) route predictions through subbasins tuned to local…