『Abstract
When describing the hydraulic relationship between rivers and
aquifers, the term disconnected is frequently misunderstood or
used in an incorrect way. The problem is compounded by the fact
that there is no definitive literature on the topic of disconnected
surface water and groundwater. We aim at closing this gap and
begin the discussion with a short introduction to the historical
background of the terminology. Even though a conceptual illustration
of a disconnected system was published by Meinzer(1923), it is
only within the last few years that the underlying physics of
the disconnection process has been described. The importance of
disconnected systems, however, is not widely appreciated. Although
rarely explicitly stated, many approaches for predicting the impacts
of groundwater development on surface water resources assume full
connection. Furthermore, management policies often suggest that
surface water and groundwater should only be managed jointly if
they are connected. However, although lowering the water table
beneath a disconnected section of a river will not change the
infiltration rate at that point, it can increase the length of
stream that is disconnected. Because knowing the state of connection
is of fundamental importance for sustainable water management,
robust field methods that allow the identification of the state
of connection are required. Currently, disconnection is identified
by showing that the infiltration rate from a stream to an underlying
aquifer is independent of the water table position or by identifying
an unsaturated zone under the stream. More field studies are required
to develop better methods for the identification of disconnection
and to quantify the implications of heterogeneity and clogging
processes in the streambed on disconnection.』
Introduction
Relationship between connection status and exchange flux
Relationship between connection status and water table position
Management implications of connection status
Terminology and historical background
Physics
Modeling approaches and identification in the field
Conclusions
Acknowledgments
References