Ground water well elevation for Niwot Ridge Saddle, 2012 - 2018.

Water level of Saddle Ground Water Wells.  Ground Water
Well locations, depths, and design were determined by Niwot Ridge LTER
lead researchers, Mark Williams and Nel Caine, to monitor
groundwater chemistry and water levels. Well locations were selected
based on proximity to the headwater region of the Saddle stream
channel. Ground Water Wells are located along an east-west transect at
the Saddle site, each pair consisting of a deep well to a depth
between 6.3 and 8.8 m, and a shallow well to a depth of 1.5 m. Ground
surface elevations at the Saddle wells range from about 3522 m at the
eastern wells to 3532 m at the western wells. The transect is roughly
170 m from east to west, has an average slope of 0.06, and is
perpendicular to the Saddle stream.  Saddle pair 3 was installed very
close to the channel. Saddle pairs 2 and 4 were installed on opposite
sides of the channel. Saddle pair 1 was installed furthest from the
channel (King, 2012). Ground water wells were installed in October 2005 by Bandimere
Geothermal Drilling Systems.  Wells are cased with 2-inch nominal pipe
size, Schedule 40 polyvinyl chloride (PVC), flush-threaded pipe. Well
screens were constructed from 0.020-inch continuous slot PVC and
installed in 5-ft (1.52 m) intervals. All of the wells have 1.52 m
screens at the bottom of the well. The bottoms of the wells were
capped with a PVC flush-threaded point cap. The annular space around
each screen and pipe was backfilled with #10-20 silica sand to act as
a filter (King, 2012).  The Niwot Ridge LTER monitoring of these Ground Water Wells has varied
over the years since the wells were installed.  Prior to 2014, all
wells were sampled weekly in summer and monthly in winter for
chemistry, and alternating wells were monitored for water level with
pressure transducers and a weighted tape measure. From 2015 through
present, Saddle Deep 3 (SD3) and Saddle Deep 4 (SD4)- those located
closest to the Saddle Stream headwaters- are being monitored for water
level, water temperature and chemistry. Depth to water and temperature
are recorded at 12 hour intervals by a Solonist Pressure Transducer.
 Additional water level measurements are taken weekly from snowmelt
through end of September, and monthly from October through snowmelt,
with a weighted tape measure and compared to pressure transduce
voltage to convert voltage to depth below surface.