Xavier Casamitjana

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The change in the stratification pattern in Boadella Reservoir (Catalonia, Spain) due to the switch in water withdrawal was investigated for a 6-month period in the year 2000. A numerical one-dimensional model (DLM) was used to predict the thermal structure of the reservoir during the period of maximum water demand. The model was found to satisfactorily(More)
We collected data and samples, from June to November of 1999 and 2000, to in situ quantify the abundance of phytoplankton in Boadella reservoir. Samples were taken at different stations along the reservoir and diatoms were persistent in the epilimnion and were the main phytoplankton component, with a peak of abundance up to ∼5 105 particles ml−1. The diatom(More)
The local response of the phytoplankton community to river inflow processes was investigated with modeling and field analyses in a long and narrow, stratified reservoir in mid-summer. The river water had high concentrations of phosphorus and nitrogen (ammonium and nitrate) and temperature had large variations at diurnal scales. As a consequence of the large(More)
Because of the difference in morphometry and in the underground heating of the two lobes of Lake Banyoles there is a differential cooling that causes a density current — the denser water of the shallower lobe plunging into the deepest lobe forming a bottom current — which redistributes water between the lobes and replaces that of the northern lobe about(More)
A great challenge in water reuse is the reduction of suspended particle concentration in wastewater. In particular the reduction of the presence of small particles in suspension which cause a cloudy appearance in the water and, which also make disinfection difficult. The present study evaluates the filtering capacity of a population of Cladodera (Daphnia(More)
Water withdrawal from Mediterranean reservoirs in summer is usually very high. Because of this, stratification is often continuous and far from the typical two-layered structure, favoring the excitation of higher vertical modes. The analysis of wind, temperature, and current data from Sau reservoir (Spain) shows that the third vertical mode of the internal(More)
The dynamics of the particle boundary layer in the Boadella reservoir was studied using an in situ laser optical particle-sizing instrument. This layer was found at the bottom of the reservoir from summer until the end of the year, when the reservoir was fully mixed. Most of the particles in this layer are remnants of the summer algae bloom and are trapped(More)
The annual limnological dynamics of two meromictic basins of Lake Banyoles (C-III and C-IV) have been studied and compared on the basis of their physical, chemical and biological characters. Stability values calculated for both basins gave 865 g cm cm−2 and 495 g cm cm−2 for C-III and C-IV respectively. These values are in agreement with the fact that C-IV(More)
In this paper, the suspension of sediments induced by groundwater jets in two basins of a karst lake (basin I and II of lake Banyoles, Catalonia) is studied. Field experiments were carried out during the period 1989-1994 to investigate the sediment dynamics within the basins. During this period, the sediment in basin I (B1) was found to be permanently in(More)
An experimental study was carried out to investigate the resuspension of particles by a momentum jet discharging from below into a conical basin. The work was motivated by its relevance to Lake Banyoles, where sediments are suspended in different conical basins by bottom jets fed by a groundwater karstic system. Two different flow regimes were identified: a(More)