5 research outputs found
Mathematical modelling as a tool for the assessment of impact of thermodynamics on the algal growth in dam reservoirs – case study of the Goczalkowice Reservoir
Depending on climate conditions, bathymetry, basin morphology, management practices and other factors, some
reservoirs are more or less prone to stratification, which can strongly affect both chemical and biological status
of water. In the Goczalkowice Reservoir (the biggest dam reservoir in the south of Poland), water quality parameters,
such as chlorophyll a concentration, change very dynamically. In the presented study, the Estuary, Lake and
Coastal Ocean Model (ELCOM) was applied to simulate water thermodynamics in a period of summer and autumn
when the highest concentrations of chlorophyll a were observed, based on the continuous water monitoring in
the ZiZOZap project (Łaszczyca et al., 2011). The purpose of the application of ELCOM was to simulate the thermal
stratification in the reservoir and to prepare a basis for analyses of the relationship between water thermodynamics
and quality. Simulations allowed the identification of several short water mixing events in summer and the final
mixing event at the end of summer. The study also included the first application of model results to analyse the
relation of changes in water temperature with observed concentration of chlorophyll a (ChlA). Analysis confirmed
that each water mixing event was followed by a significant increase in ChlA concentration
Phytoplankton production in relation to simulated hydro- and thermodynamics during a hydrological wet year – Goczałkowice reservoir (Poland) case study
Phytoplankton is one of the crucial components of water body ecosystems. Its presence and development depend
on biological, physical and chemical factors and in consequence it is an important indicator of ecosystem condition.
Monitoring of phytoplankton production, measured as chlorophyll a concentration, is a useful tool for
assessing the status of dam reservoirs. Modeled chlorophyll a concentrations are used as water quality indicators
in locations not included in monitoring systems, in situations when the temporal resolution of the monitoring is
not enough, and in assessments of the impacts of future activities. Therefore, the aim of this study was to find
correlations between hydro- and thermodynamics and the chlorophyll a concentration for possible application in
reservoir monitoring and management, using an ELCOM-CAEDYM model. The analysis included summer and fall
which are most prone to algal blooms, and four phytoplankton groups identified as dominant in the reservoir
based on periodic observations.
Comparisons of simulated water temperature and both observed and simulated chlorophyll a concentrations
confirmed that these variables are significantly correlated (correlation of hourly chlorophyll a and water temperature
was 0.70, ranging from 0.55 to 0.81 in the bottom and surface water layers, respectively, while for daily
outputs it was 0.74, ranging from 0.60 to 0.83). This relation was stronger than that of chlorophyll a to nutrient
(N, P and Si) concentrations. What is more, the method used allowed the assessment of a much more detailed
spatial and temporal distribution of phytoplankton groups compared with conventional monitoring techniques.
The study indicated that the phytoplankton community was dominated by Chlorophytes and Diatoms with a
larger share of Chlorophytes in shallow parts of the reservoir. This domination was weaker after short water
mixing events in summer and especially after the fall turnover. The increase in phytoplankton diversity was
estimated to occur mainly near the surface and in shallow parts of the reservoir. Most of the observed concentrations
of individual phytoplankton groups differed from simulation results by less than 25% and the model
reflected accurately 74% of observed trends in concentrations. Calculated chlorophyll a concentration was well
matched to hourly monitoring data (mean squared error = 5.6, Nash–Sutcliffe model efficiency coefficient =
0.51, Pearson correlation coefficient = 0.72 and p-value = 0.0007).
High compatibility of the model to the values measured in the reservoir make it a promising tool for the
prediction and planning of actions aimed at maintaining good functioning of the reservoir
Mathematical modelling as a tool for the assessment of impact of thermodynamics on the algal growth in dam reservoirs – case study of the Goczalkowice Reservoir
Depending on climate conditions, bathymetry, basin morphology, management practices and other factors, some reservoirs are more or less prone to stratification, which can strongly affect both chemical and biological status of water. In the Goczalkowice Reservoir (the biggest dam reservoir in the south of Poland), water quality parameters, such as chlorophyll a concentration, change very dynamically. In the presented study, the Estuary, Lake and Coastal Ocean Model (ELCOM) was applied to simulate water thermodynamics in a period of summer and autumn when the highest concentrations of chlorophyll a were observed, based on the continuous water monitoring in the ZiZOZap project (Łaszczyca et al., 2011). The purpose of the application of ELCOM was to simulate the thermal stratification in the reservoir and to prepare a basis for analyses of the relationship between water thermodynamics and quality. Simulations allowed the identification of several short water mixing events in summer and the final mixing event at the end of summer. The study also included the first application of model results to analyse the relation of changes in water temperature with observed concentration of chlorophyll a (ChlA). Analysis confirmed that each water mixing event was followed by a significant increase in ChlA concentration