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Volumetric and Mid-Section Discharge Measurement data, Summer through Fall 2020, H.J. Andrews Experimental Forest, Lookout Creek Basin, Oregon

March 16, 2022

Discrete volumetric and mid-section stream discharge measurements were conducted from July through October 2020 in H.J. Andrews Experimental Forest near Blue River, OR. The measured streams are part of the Lookout Creek basin, draining into Blue River and subsequently the McKenzie River on the west slope of the Cascade Range. ORWSC Streamflow measurements supplemented an eco-drought low-flow modeling project in partnership with the Forest and Rangeland Ecosystem Science Center (FRESC) and the USGS Water Mission Area (WMA). Measurements were collected at 25 selected sites with co-located HOBO data loggers and 7 miscellaneous (MISC) sites with no data loggers present. HOBO logger data were collected and processed by FRESC team members. Volumetric measurements were collected by placing a modified weir into the stream and directing the entire streamflow over the weir, easing the collection of water into a bucket. Collections of water were timed to the hundredth of a second using a stopwatch, and volumes were measured with a graduated cylinder in 20 ml increments. Mid-section measurements were conducted following USGS protocol, wading in streams using SonTek FlowTracker-2 handheld acoustic Doppler velocimeters. Sites were measured during two field runs occurring July 6th through 10th 2020 and August 10th through 14th 2020. Two of the sites were measured a third time on October 26th and 27th, 2020, to compare midsection measurements with volumetric measurements. In the streams with HOBO dataloggers, the volumetric measurements achieved satisfactory channeling of the streams with the weir method and are considered more accurate with less uncertainty than the mid-section measurements. Steep channel conditions, large boulders and cobbles through the channel cross-section, large stream velocity angles, non-standard stream velocity profiles, and the channelization of flows created unideal conditions for midsection measurements. The MISC streamflow measurements were conducted at adequate channel cross-sections detailed by USGS protocols.