Abstracts

The chloride mass balance method is then applied to data collected at three sites in southern
Alberta. All three sites are situated in the north-western fringe of the prairie belt
with two sites falling within the boundaries of the parkland ecoregion and third site being
situated in the grassland ecoregion The instruments deployed on the sites permitted to
quantify intensity of the lateral water fluxes. The chloride concentration data were obtained
from the till samples obtained during groundwater well installation in 2014. As
a result, chloride concentrations in the till coupled with information on the lateral water
fluxes allowed us to estimate recharge rate and to compare it with an apparent recharge rate
to demonstrate the magnitude of the bias in a real setting.
283 - Simulated mechanical compression of regenerated
Sphagnum moss potentially accelerates the return of hydrological
functionality in restored bogs
Colin McCarter & Jonathan Price
University of Waterloo, Waterloo, Ontario, Canada
Returning the ecohydrological function to harvested bog peatlands is critical to restoration;
however, after 10 years the current restoration approach does not achieve this milestone, due
to the capillary barrier formed between the regenerated Sphagnum moss and relatively dense
remnant cutover peat. A greater proportion of large pores was observed in the regenerated
Sphagnum that limited capillary draw from the remnant peat. Increasing the density of small
pores in the regenerated Sphagnum would increase its capillarity and allow greater connection
to the water table, which is situated within the remnant cutover peat. This paper aims to assess
the theoretical implications of compression through modelling increases in volumetric soil
moisture content (θ) and unsaturated hydraulic conductivity (K unsat
), representing an increase
in the abundance of smaller pores. Hydrus-1D, utilizing the van Geuchten-Mualem or Durner
dual porosity equation, was used to simulate the current vadose hydrology of regenerated
Sphagnum, along with an undisturbed analogue as reference simulations. Both K unsat
and θ
were increased by 50 % of the difference between the restored and undisturbed Sphagnum
(~1 order of magnitude in K unsat
and 2 – 5 % in θ) and the Sphagnum height decreased by
50 % to 10 cm to simulate compression. Unlike the undisturbed analogue, the regenerated
Sphagnum had highly non-linear soil water pressure distribution, resulting in limited upward
transfer of water to the surface and meeting the evaporative demand ~28 % of the time (~60 %
for undisturbed). Compression achieved linear soil water pressure distributions, similar to undisturbed,
and a large increase in its ability to meet the evaporative demand (57 %). A 2 order
of magnitude increase in average Sphagnum K unsat
(6.2·10 -5 to 1.8·10 -3 cm hr -1 ) was observed
between the regenerated and compressed models, but was still lower than the Sphagnum
K unsat
of the undisturbed (1.5·10 -1 cm hr -1 ). Furthermore, the simulated compression allowed
the water table (minimum -0.82 m bgs) to be influenced by the Sphagnum moss, unlike the
regenerated Sphagnum that had no influence on water table position. These results indicate
that it is possible to have direct connection from the water table to the surface by decreasing
the average pore size and increasing θ and K unsat
, even when the water table resides within the
remnant cutover peat. Mechanical compression of living Sphagnum moss may be a practical
remedial restoration measure to improve hydrological function.
IAH-CNC 2015 WATERLOO CONFERENCE
83