| Dam-affected hydrologic time series give rise to uncertainties when they are
used for calibrating large-scale hydrologic models or for analysing runoff
records. It is therefore necessary to identify and to quantify the impact of
impoundments on runoff time series. Two different approaches were employed.
The first, classic approach compares the volume of the dams that are located
upstream from a station with the annual discharge. The catchment areas of
the stations are calculated and then related to geo-referenced dam
attributes. The paper introduces a data set of geo-referenced dams linked
with 677 gauging stations in Europe.
Second, the intensity of the impoundment impact on runoff times series can
be quantified more exactly and directly when long-term runoff records are
available. Dams cause a change in the variability of flow regimes. This
effect can be measured using the model of linear single storage. The
dam-caused storage change ΔS can be assessed through the volume of
the emptying process between two flow regimes. As an example, the storage
change ΔS is calculated for regulated long-term series of the
Luleälven in northern Sweden. |