Groundwater response to stream
stage fluctuations in a regulated
stream, New Martinsville, WV
Madan Maharjan
Joe Donovan
West Virginia University
Research interest
• Regulated streams are also transportation
corridors for rail as well as industrial areas and
tend to be sites of groundwater contamination,
including some public water supplies.
• If the management of dams alters or controls
groundwater flow here, then we may benefit from
understanding how these controls work.
Background
b
a
Purpose
• To develop an analytical model that explains spatial and
temporal aspects of surface-and groundwater interaction
during an annual cycle of stream stage fluctuation;
• To estimate induced infiltration rate and bank storage
using this model; and
• To distinguish vertical (i.e. recharge) from lateral (i.e.
induced infiltration) stress.
Hypothesis
• Lateral (stream-induced) stress is more prominent
than vertical stress (recharge) during high flow
periods and vice-versa in low flow periods.
Approach
• A convolution-integral method was written in
MATLAB to simulate aquifer heads in response to
stream stage fluctuations (Hall and Moench,
1972).
Geology & A Conceptual Model
Assumptions
• Aquifer has a negligible head gradient towards a pumping well;
• Stream stage fluctuation was the main and only source of
aquifer head fluctuation;
• End of the baseflow recession was at steady state condition;
• Recharge from precipitation was uniformly distributed.
River stage and well heads across the dam
Negative correlation
High flow period
Low flow period
Observed and modeled well heads across dam
Vertical and
lateral infiltration
Lateral infiltration only
Vertical infiltration
Vertical infiltration and lateral groundwater flow from upper pool
Observed and modeled well heads in the lower pool
50 cm
182.15m
20 cm
181.7m
Bank storage and seepage rate in the upper pool
Inflow into aquifer
Outflow from aquifer
Bank storage and seepage rate in the lower pool
Storms
Outflow period
Low flow period
Inflow period
High flow period
Limitation of the model
• Estimated values could differ significantly from the
actual values, in settings where
• significant regional gradient and/or aquifer
heterogeneity are present; and
• the stream partially penetrates the aquifer.
Conclusions
1. Stream stage fluctuations exerted greater control over
groundwater levels than recharge especially during high
flow periods;
2. Anthropogenic activities could change groundwater flow
paths and velocity; and
3. This method could be a useful tool identifying potential
threats to water quality and planning future well field
expansion or management.
Thank you
Questions
Method
(1)
h(x,t)= ΔH* erfc (
(2)
h(x,t)=
(3)
V=
(4)
v= V*n
(5)
Q=
(6)
H=Stream stage
h= Aquifer head
D= Aquifer diffusivity
Erfc=Complimentary
error function
V=Unit-width saturated
aquifer volume
v=Bank storage
Q=Seepage rate
River Stage Across Hannibal Locks and Dam
Glen Dale PWS