Water Flow on the Upper Millers

There are a few USACE gages that help indicate the flow on the Upper Millers:

Birch Hill Dam - out-flow fro the dam at the top of the run.
https://reservoircontrol.usace.army.mil/nae_ords/cwmsweb/cwms_realtime.ProjectPage?gagecode=BHD

South Royalston – gage at the put-in
https://reservoircontrol.usace.army.mil/nae_ords/cwmsweb/cwms_realtime.riverpage?gagecode=ROY

Tully Dam – additional flow from the Tully River
https://reservoircontrol.usace.army.mil/nae_ords/cwmsweb/cwms_realtime.ProjectPage?gagecode=TLD

Athol – flow below the take-out and the Tully River
https://reservoircontrol.usace.army.mil/nae_ords/cwmsweb/cwms_realtime.ProjectPage?gagecode=ATH

According to Kaz, you can deduct the flow from the Tully River from the flow in Athol to determine the approximate amount of water in the river between South Royalston and Athol. I usually just look at the outflow from Birch Hill Dam or the South Royalston gage.