Downhole flowmeter choice for ambient vertical flow

Has anyone run heat‑pulse flowmeters in 6‑inch PVC monitoring wells to quantify ambient vertical flow and hydraulic connectivity between layers? I’m working this fall in a semi‑confined alluvial–basalt system near Boise (30–80 m wells; seasonal head swing about 0.4–0.6 m) and I’m weighing heat‑pulse vs electromagnetic units, plus whether to pair with short‑interval packers and DTS/heat‑as‑tracer, to resolve cross‑formational leakage and set sustainable pumping limits that won’t rob stream baseflow. Would appreciate real‑world thresholds on detectable velocities/flow (e.g., <0.2 L/min), drift issues, and workflows that fed cleanly into MODFLOW 6 layer budgets.

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