Improving and Testing the Prairie Hydrological Model at Smith Creek Research Basin
Date
2014
Authors
Pomeroy, John W.
Shook, Kevin
Fang, Xing
Dumanski, Stacey
Westbrook, Cherie
Brown, Tom
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Centre for Hydrology, University of Saskatchewan, Saskatoon, Saskatchewan
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Technical Report
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Abstract
The 2010 Prairie Hydrological Model configuration of the Cold Regions Hydrological Model was
developed to include improved snowmelt and evaporation physics and a hysteretic relationship
between wetland storage and runoff contributing area. The revised model was used to
simulate the snow regimes on and the streamflow runoff from the five sub-basins and main
basin of Smith Creek, Saskatchewan for six years (2007-2013) with good performance when
compared to field observations. Smith Creek measured streamflows over this period included
the highest annual flow volume on record (2011) and high flows from heavy summer rains in
2012. Smith Creek basin has undergone substantial drainage from 1958 when it contained 96
km2 of wetlands covering 24% of the basin area to the existing (2008 measurement) 43 km2
covering 11% of the basin. The Prairie Hydrological Model was run over the 2007-2013 period
for various wetland extent scenarios that included the 1958 historical maximum, measured
extents in 2000 and 2008, a minimum extent that excluded drainage of conservation lands and
an extreme minimum extent involving complete drainage of all wetlands in Smith Creek basin.
Overall, Smith Creek total flow volumes over six years increase 55% due to drainage of wetlands
from the current (2008) state, and decrease 26% with restoration to the 1958 state. This
sensitivity in flow volume to wetland change is crucially important for the water balance of
downstream water bodies such as Lake Winnipeg. Whilst the greatest proportional impacts on
the peak daily flows are for dry years, substantial impacts on the peak daily discharge of record
(2011) from wetland drainage (+78%) or restoration (-32%) are notable and important for
infrastructure in and downstream of Smith Creek. For the flood of record (2011), the annual
flow volume and the peak daily discharge are estimated to increase from 57,317 to 81,227
dam3 and from 19.5 to 27.5 m3
/s, respectively, due to wetland drainage that has already
occurred in Smith Creek. Although Smith Creek is already heavily drained and its streamflows
have been impacted, the annual flow volumes and peak daily discharge for the flood of record
can still be strongly increased by complete drainage from the 2008 wetland state, rising to
103,669 dam3 and 49 m3
/s respectively. This model simulation exercise shows that wetland
drainage can increase annual and peak daily flows substantially, and that notable increases to
estimates of the annual volume and peak daily flow of the flood of record have derived from
wetland drainage and will proceed with further wetland drainage.
Description
Keywords
Wetland drainage, Prairies, Cold Regions Hydrological Model, Hydrological modelling, Runoff, Land use change, Streamflow, Smith Creek, Saskatchewan
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Centre for Hydrology Report #14