Journal Article Summary
In their journal article titled
“Controls of Groundwater Floodwave Propagation in Gravelly Floodplain, Cloutier
et al. (2014) are interested in the relationship between the surface water and
groundwater in the floodplain of the Matane River, which is located in eastern
Canada and which drains a 1678 square kilometer basin. As described in the
article, the mean annual discharge of the stream, collected from the Matane
gauging station, is 39 m3 per second, with the highest discharge in
May. In the research study, the author proposed two feasible scenarios of
driving mechanisms of the rise of groundwater which ultimately causes flood to
occur, and these two scenarios are: (1) complete saturation of subsurface
strata due to precipitation over a long period of time and (2) river stage
fluctuation. Each scenario was analyzed, and the result showed that river stage
fluctuation had stronger effect on the rising of groundwater level.
For data collection, eleven
piezometers were installed at the study site for 173 days in the summer and
fall of 2011 (from 21 June to 12 December 2011) in order to examine the
hydraulic heads of the floodplain, the ground water flows, and stream outflows
where there is an occurrence of groundwater exfiltration. The authors also
mention that there are evidences of the success of using the arrays of
piezometers for documenting the interactions between surface water and
groundwater. For the first 79 days, from
21 June to 7 September, eight of the eleven piezometers were used accompanied
by transducers (Hobo U20-001) to automatically record the water level at every
15 minutes. Then, starting from September 7 onwards, three more pressure
transducers were added to the rest of piezometers, D139, D21, and D 196 (Cloutier
et al., 2014). At upstream and downstream of the experimental site, two river
stage gauges were installed on the river bed with an intent to monitor water
levels in the river at every 15 minutes for the whole of the study period. Magellan ProMak III differential GPS was used
to measure the locations of piezometers, a LIDAR survey to obtain a topographic
map, and a tipping bucket pluviometer to measure the rainfall data (Cloutier et
al., 2014).
At the piezometer stations and
river station gauge upstream (RSGup), the water levels and river stages were
higher than those of stations, and hence there is no problem with time series
dat. However, at the river station gauge downstream (RCGdn), the rivers stages
occasionally dropped below the data logger, resulting in discontinuous time
series. To deal with this, the authors decided to use the RSGdn time series
only from 5 to 12 September. Alternatively, cross-correlation analyses,
performed with the PAST software, were adopted to determine the time lags between
time series of the river stages and the water level at the piezometers
(Cloutier et al., 2014). In addition, this method was also used to obtain the
information concerning the strength of the input-output relationships as well
as the time lags between the processes. Owing to the small distance between the
two river gauges, no significant lag between RSGup and RSGdn was account for.
The results from the study show
that the relationships between the water level in the river and ground water is
much stronger than that between precipitation and groundwater due to the fact
that the input from precipitation has been hugely reduced by the unsaturated
zone which are able to store a large amount of water. It is also interpreted
that the amplitude of groundwater fluctuation is disproportional to the
distance from the river (Cloutier et al. 2014), meaning that the further the
distance from the river, the lower the amplitude of the groundwater
fluctuations. In addition, the result also suggests that “fluctuations of
hydraulic head correspond to the propagation of groundwater floodwave
throughout the floodplain” (Cloutier et al., 2014).
The aforementioned research study,
I believe, is essential for later study about surface water-groundwater
interaction, especially in the state of Florida where ground water is known to
be the indispensable source of drinking water and other usage, and in which
there is a strong connection between surface water and groundwater. According
to Florida Department of Environmental Protection (2013), in the state of
Florida, 90 percent of its population depends on groundwater for drinking
water. In their article, Winter et al. (1998) wrote that almost all, if not
all, of surface-water features such as streams, lakes, reservoirs, wetlands,
estuaries, and the like has interactions with underground water, and often
times surface-water bodies gain water from the groundwater and vice versa,
which implies that they are closely related to each other and if one is
polluted or affected, the other will also be affected. Therefore, I think that
the study by Clotier et al. (2014) is useful and can be used as a case study in
Florida where a strong connection between surface and groundwater is present. More
importantly, understanding the surface water-groundwater interaction helps
water engineers, hydraulic engineers, water resource managers, as well as other
stakeholders in water-related policy forming effectively manage the local water
resource and protect the water resource.
References
Cloutier, A. C., Bélanger, B. T, and Larocque, M. (2014). “Controls
of groundwater floodwave propagation in a gravelly floodplain.” Journal of hydrology.
511(2014) 423-431. Retrieved on 03/16/2014 from http://www.sciencedirect.com/science/article/pii/S0022169414001115
Florida Department of
Environmental Protection (2014). Retrieved on 03/16/2014 from http://www.dep.state.fl.us/water/groundwater/whatis.htm
Winter, C. T., Harvey. W. J., Franke, L. O., and
Alley, William, M. W. (1998). Groundwater and surface Water A Single Resource.
U.S. Geological Survey Circular 1139. Denver, Colorado. Retrieved on 03/16/2014
from http://pubs.usgs.gov/circ/circ1139/pdf/circ1139.pdf
