Hubbard Brook Experimental Forest: Daily Streamflow by Watershed, 1956 - present

Streamflow at 9 watersheds within the Hubbard Brook Experimental
Forest has been measured continuously from as early as 1955. Streams
are gaged with V-notch weirs at the outlet of each watershed. Height
of water behind the weir increases with increased streamflow and is
recorded by means of a float attached mechanically to a pen on a
spring-wound strip-chart recorder. Gage height is converted to
streamflow rate by calibration factors and then integrated to generate
daily streamflow. Streamflow rate is measured as volume per unit
time(L/s) and is proportional to the watershed area.

Beginning January 1, 2013, instantaneous streamflow data (and derived
daily streamflow) are measured by electronic sensors, and data are
provisional as the transition from chart to digital data collection is
still under evaluation. Data may be updated before they are finalized.
Please contact the dataset creator prior to data use/publication.
Daily streamflow data are derived from the instantaneous streamflow
record, and additional information (quality control flagging and
gapfilling) can be found in that record
https://portal.lternet.edu/nis/mapbrowse?scope=knb-lter-hbr&identifier=1

In 2016, a new, more comprehensive gapfilling method was used, wherein
data removed by QC flagging are calculated with a regression ensemble,
using data from all remaining weirs that have data passing QC tests.
The median of the predicted 5-minute discharge rates based on
regression with the remaining weirs was used as the robust prediction
of discharge for a data gap. Additionally, the difference between the
prediction and the actual values at the beginning and end of a gap
were set to zero to “snap” the prediction to the adjacent measured
values.

These data were gathered as part of the Hubbard Brook Ecosystem Study
(HBES). The HBES is a collaborative effort at the Hubbard Brook
Experimental Forest, which is operated and maintained by the USDA
Forest Service, Northern Research Station.