Soil water program
Soil water from three soil profiles (called the S-transect) located 4,
12 and 22 m from the C2 stream have been monitored 5-12 times per year
since 1995 for water isotopes and water chemistry (Nyberg et al. 2001;
Bishop et al., 2004; Lidman et al. 2017, Blackburn et al. 2017). The
S-transect is aligned based on topography, following the lateral
flowpath of groundwater. Each profile consists of measurements at six
soil depths between 5 and 90 cm using ceramic suction lysimeters (P100).
Soil water content using Time-domain reflectometry (TDR) and soil
temperatures are measured at the same depths. A similar setup was
installed in one of the wetland soils upstream of C4 to monitor soil
water chemistry since 1997 using 12 nested wells extending to different
depths, ranging from 25 to 350 cm below the ground surface (Lidman et
al. 2013; Sponseller et al. 2018). ). In 2007, the Riparian Observatory
of Krycklan, a complementary set of transects to represent a range of
topographic situations was also established (Grabs et al., 2012).
Ten pairs of DRIP (Discrete Riparian Inflow Point) and non-DRIP well
transects were established in 2015 in riparian zones in central KCS
streams (Fig. 1d). Each pair is located adjacent to each other and
therefore experience comparable environmental conditions, except for in
the groundwater hydrology. DRIP sites are located on the receiving end
of converging groundwater flow paths, and are characterized by shallow
water tables, often reaching the soil surface before converging with
streams (see Leach et al. 2017). Non-DRIP sites are situated in more
elevated, drier riparian areas. Each transect is equipped with three
fully screened groundwater wells, situated in riparian (0-3 m distance
from the stream), transition (10 m distance from the stream), and upland
(20 m distance from the stream) areas (Ploum et al. 2020).