Abstract
Understanding the spatial distribution of discharge
can be important for water quality and quantity modeling.
Non-steady flood waves can, particularly as a result of short
high intensity summer rainstorms, influence small headwater
streams significantly. The aim of this paper is to quantify the
spatial and temporal dynamics of stream flow in a headwater
stream during a summer rainstorm. These dynamics include
gains and losses of stream water, the effect of bypasses that
become active and hyporheic exchange fluxes that may vary
over time as a function of discharge. We use an advectiondispersion
model coupled with an energy balance model to
simulate in-stream water temperature, which we compare
with high resolution temperature observations obtained with
Distributed Temperature Sensing. This model was used as a
learning tool to stepwise unravel the complex puzzle of instream
processes subject to varying discharge. Hypotheses
were tested and rejected, which led to more insight in the
spatial and temporal dynamics in discharge and hyporheic
exchange processes. We showed that, for the studied stream
infiltration losses increase during a small rain event, while
gains of water remained constant over time. We conclude
that, eventually, part of the stream water bypassed the main
channel during peak discharge. It also seems that hyporheic
exchange varies with varying discharge in the first 250m of
the stream; while further downstream it remains constant.
Because we relied on solar radiation as the main energy input,
we were only able to apply this method during a small
summer storm and low flow conditions. However, when additional
(artificial) energy is available, the presented method
is also applicable in larger streams, during higher flow conditions
or longer storms.
can be important for water quality and quantity modeling.
Non-steady flood waves can, particularly as a result of short
high intensity summer rainstorms, influence small headwater
streams significantly. The aim of this paper is to quantify the
spatial and temporal dynamics of stream flow in a headwater
stream during a summer rainstorm. These dynamics include
gains and losses of stream water, the effect of bypasses that
become active and hyporheic exchange fluxes that may vary
over time as a function of discharge. We use an advectiondispersion
model coupled with an energy balance model to
simulate in-stream water temperature, which we compare
with high resolution temperature observations obtained with
Distributed Temperature Sensing. This model was used as a
learning tool to stepwise unravel the complex puzzle of instream
processes subject to varying discharge. Hypotheses
were tested and rejected, which led to more insight in the
spatial and temporal dynamics in discharge and hyporheic
exchange processes. We showed that, for the studied stream
infiltration losses increase during a small rain event, while
gains of water remained constant over time. We conclude
that, eventually, part of the stream water bypassed the main
channel during peak discharge. It also seems that hyporheic
exchange varies with varying discharge in the first 250m of
the stream; while further downstream it remains constant.
Because we relied on solar radiation as the main energy input,
we were only able to apply this method during a small
summer storm and low flow conditions. However, when additional
(artificial) energy is available, the presented method
is also applicable in larger streams, during higher flow conditions
or longer storms.
| Original language | English |
|---|---|
| Pages (from-to) | 1945-1957 |
| Journal | Hydrology and Earth System Sciences |
| Volume | 15 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2011 |
