Environmental Engineering Reference
In-Depth Information
19.1
Introduction: How a Small Danish Lake Helped to
Advance the Development of Ecological Modelling
As new scientific options and approaches emerge, they are frequently tested and
applied in a reference case. One such case with a high impact on ecological
modelling was the development of the Lake Glumsø model. The lake is a small,
shallow, post-glacial lake in Denmark situated on the Danish island of Seeland,
78 km away from the capital, Copenhagen with 266,000 m
2
surface area and 2.4 m
maximum depth. This chapter will outline the importance of this lake to the
advancement of ecological modelling over a time span of more than 30 years. It
also presents an interesting illustration on how the results from a prototypic case
may inspire a wide range of other work and developments in application as well as
in establishing new techniques.
19.1.1 Why Studying Lake Glumsø?
There is nothing special about this lake. In Denmark, Sweden, Germany, Poland
and various other countries throughout the Northern temperate climate zone there
are similar post-glacial lakes. Therefore, results obtained for one of them can be
helpful to understand the situation of many others: it is a prototypic case. Lake
Glumsø, was selected as a case study because: (1) the hydrology was simple, (2) the
municipality had planned and decided to invest in waste water treatment to clean up
the lake, (3) the lake was highly eutrophic, which made it reasonable to expect a
significant improvement following the intended measure, (4) the retention time was
only 5 months allowing a fast response of the lake to validate model prognoses.
During development of the model for Lake Glumsø it was possible to provide a
robust model structure that was widely applicable to simulate dynamic processes
requiring minor or moderate adaptation to be used for other lakes, estuaries,
reservoirs and near coastal waters. The modifications required the parametrisation
of involved processes referring to, e.g., size, depth, and nutrient load. As a proto-
type, the Glumsø model contained the relevant variables, functions and parameters
in a clearly presented and well accessible form.
Starting in the 1970s, lake modelling had become important for several reasons.
As a result of an increased use of chemicals in households and diversion of more or
less untreated sewage into lakes, as well as an increased use of chemical fertiliser
inputs in agriculture, eutrophication of lakes and rivers had become widespread and
a major concern in environmental protection. As other works suggest (e.g. Scheffer
et al. 1993), specific concepts were required to understand the dynamics of the
involved processes, in particular to estimate potential outcomes of management
measures to anticipate effort and the achievable results. Important pioneer work in
these fields has been done using the Glumsø study site.
