Zeitschriften und Ausgaben

Volumen 21 (2021): Heft 4 (December 2021)

Volumen 21 (2021): Heft 3 (September 2021)

Volumen 21 (2021): Heft 2 (June 2021)

Volumen 21 (2021): Heft 1 (March 2021)

Volumen 20 (2020): Heft 4 (December 2020)

Volumen 20 (2020): Heft 3 (September 2020)

Volumen 20 (2020): Heft 2 (June 2020)

Volumen 20 (2020): Heft 1 (March 2020)

Volumen 19 (2019): Heft 4 (December 2019)

Volumen 19 (2019): Heft 3 (September 2019)

Volumen 19 (2019): Heft 2 (June 2019)

Volumen 19 (2019): Heft 1 (March 2019)

Volumen 18 (2018): Heft 4 (December 2018)

Volumen 18 (2018): Heft 3 (September 2018)

Volumen 18 (2018): Heft 2 (June 2018)

Volumen 18 (2018): Heft 1 (March 2018)

Volumen 17 (2017): Heft 4 (December 2017)

Volumen 17 (2017): Heft 3 (September 2017)

Volumen 17 (2017): Heft 2 (June 2017)

Volumen 17 (2017): Heft 1 (March 2017)

Volumen 16 (2016): Heft 4 (December 2016)

Volumen 16 (2016): Heft 3 (September 2016)

Volumen 16 (2016): Heft 2 (June 2016)

Volumen 16 (2016): Heft 1 (March 2016)

Volumen 15 (2015): Heft 4 (December 2015)

Volumen 15 (2015): Heft 3 (September 2015)

Volumen 15 (2015): Heft 2 (June 2015)

Volumen 15 (2015): Heft 1 (March 2015)

Volumen 14 (2014): Heft 4 (December 2014)

Volumen 14 (2014): Heft 3 (September 2014)

Volumen 14 (2014): Heft 2 (June 2014)

Volumen 14 (2014): Heft 1 (March 2014)

Volumen 13 (2013): Heft 4 (December 2013)

Volumen 13 (2013): Heft 3 (September 2013)

Volumen 13 (2013): Heft 2 (June 2013)

Volumen 13 (2013): Heft 1 (March 2013)

Volumen 12 (2012): Heft 4 (December 2012)

Volumen 12 (2012): Heft 3 (September 2012)

Volumen 12 (2012): Heft 2 (June 2012)

Volumen 12 (2012): Heft 1 (March 2012)

Volumen 11 (2011): Heft 4 (December 2011)

Volumen 11 (2011): Heft 3 (September 2011)

Volumen 11 (2011): Heft 2 (June 2011)

Volumen 11 (2011): Heft 1 (March 2011)

Volumen 10 (2010): Heft 3-4 (December 2010)

Volumen 10 (2010): Heft 2 (June 2010)

Volumen 10 (2010): Heft 1 (March 2010)

Zeitschriftendaten
Format
Zeitschrift
eISSN
2300-7575
Erstveröffentlichung
17 Mar 2011
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

Volumen 14 (2014): Heft 1 (March 2014)

Zeitschriftendaten
Format
Zeitschrift
eISSN
2300-7575
Erstveröffentlichung
17 Mar 2011
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

6 Artikel
Uneingeschränkter Zugang

A new water energy dissipater for efficient energy dissipation and enriching the flow with dissolved oxygen content

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 3 - 11

Zusammenfassung

Abstract

One of the most important problems Egypt is facing nowadays is saving and controlling the limited available quantity of water and its quality for irrigation and other purposes. Such goals may be achieved through different types of diversion head structures across the river and in the entrance of other carrying canals. The construction of diversion head structures, which usually causes many technical problems, should have the objective of solving and overcoming to protect the structure from failure. The main problem occurs downstream. Such structures have the harmful effect of converting the potential energy gained in the upstream side to a kinetic energy in the downstream side. This energy must be dissipated shortly and safely as near as possible to the head structure to avoid its destructive effect. The hydraulic jump is the most effective tool for the dissipation of water energy, accelerating the forming of the hydraulic jump downstream such structures became essential for achieving our main goal. Using energy dissipaters on the soled apron in the downstream side of the structures was the main technique for accelerating the hydraulic jump formation and dissipating great amount of the residual harmful kinetic energy occurring downstream head structures. So early, many researchers investigated different types, shapes, and arrangements of such dissipaters to evaluate its efficiency in dissipating the water energy and accelerating the forming of the hydraulic jump. In fact, in our present study we will try to investigate some other shapes of energy dissipaters, which have not been studied enough, by evaluating its positive technical impact on: (i) percentage value of dissipating kinetic water energy; (ii) percentage value of increasing the dissolved oxygen (DO) content in the irrigation water, and improving its quality. The study is proposed to be held in the irrigation and hydraulic laboratory of the Civil department, Faculty of Engineering, Assiut University, using a movable bed tilting channel 20 m long, 30 cm wide, and 50 cm high, using fourteen types of curved dissipaters with different arrangements as shown in Table 2. It is worth mentioning that, in this first part of our paper, we will introduce a comparative analysis for the efficiency of different types of energy dissipaters available in the literature review. The most effective types of the previously studied dissipaters will be put in a comparison with our new dissipaters from the two above mentioned points of view, and the results will be presented in the second part of this paper later.

Keywords

  • energy dissipation
  • hydraulic jump
  • curved sill dissipater
  • water quality
  • dissolved oxygen
Uneingeschränkter Zugang

Phases and interruptions in postglacial development of humic lake margin (Lake Suchar Wielki, NE Poland)

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 13 - 20

Zusammenfassung

Abstract

Our study concerns the development of marginal zone of Lake Suchar Wielki (Wigry National Park). This humic lake is characterised by mire occurrence in its marginal zone, covered with a floating mat spreading on water surface. Biogenic sediments (peat archive) present in lakeside allow recognising the thousands years’ development pattern of lake surrounded by mire. The wetland records were analysed for plant macroremains, degree of peat decomposition, sediment geochemical features along with age assessment. Morphological characteristics of the catchment were integrated with the wetland records. Our research showed that after the lake origin in the Allerod, accumulation in its marginal zone was interrupted, which was probably connected with high precipitation in the past. Slope processes could be possible. Stabilisation of environmental conditions took place in the younger Holocene. Despite these perturbations marginal zone of the lake was permanently terrestrial in character, as indicated by values of atomic C:N ratio.

Keywords

  • humic lake
  • peat archive
  • hiatus
  • marginal zone of lake
  • C:N ratio
Uneingeschränkter Zugang

The structure and spatial heterogeneity of zooplankton in small lake river Wel (Poland)

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 21 - 31

Zusammenfassung

Abstract

The aim of the study was to determine changes in potamoplankton structure caused by lakes in the fluvial system of the small River Wel. The river flows through 10 lakes. The study was conducted in 2007 and 2008. The selection of sites enabled the assessment of the impact exerted by hydrological conditions of the river on zooplankton, as well as the determination of the effect of lakes situated within the river course on the analysed assemblage of organisms. In total 95 species were determined with an average abundance 1026 ind. 10 dm-3. Rotifers dominated qualitatively and quantitatively and among crustaceans - Copepods. Lakes seem to be the main source of zooplankton in the fluvial system of the Wel River. The lakes disturb the river continuum, but their impact on the structure of zooplankton is short-lived. Due to the presence of flow-through lakes along the river, species richness of zooplankton in the Wel River is similar to that in large rivers.

Schlüsselwörter

  • fluvial system
  • river continuum
  • potamoplankton
  • Rotifers
  • Cladocera
  • Copepoda
Uneingeschränkter Zugang

Changing the geometry of basins and water resources of Lakes Gopło and Ostrowskie under the influence of anthropopressure

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 33 - 43

Zusammenfassung

Abstract

The paper presents the changes that have occurred in the morphometry of Lakes Gopło and Ostrowskie, which are located in central Poland. The analysis covered the period characterised by increased human interference into the water cycle, which has been taking place continually since the mid-eighteenth century. On the basis of available cartographic materials (aerial photographs, topographic maps, bathymetric charts of the lakes) and the authors’ own field measurements digital terrain models were developed for the immediate environment of the surveyed lakes. These models, in turn, were used for measuring basic parameters characterising the external dimensions of the lakes (surface area, length and maximum width, shoreline length) and their underwater relief (volume, maximum and average depth). In addition, the selected indicators of the shape and form of the lake basins were determined. The results showed a drastic reduction of water resources of the two lakes. The basin of Lake Gopło covers only the deepest parts of the former reservoir, accounting for only 23.3% of the lake before 1772, and 32.5% of its former volume. In the case of Lake Ostrowskie the surface area and volume decreased, respectively, by 23.5% (74.9 ha) and 21.3% (6 695 000 m3). Such large changes in surface area and volume of both lakes have contributed to significant changes in other morphometric parameters and indicators. In particular, significant changes were observed in relation to such morphometric characteristics as length and maximum width, as well as average and maximum depth.

Keywords

  • cartographic analysis
  • transformation of the water cycle
  • disappearance of lakes
  • lake morphometry
  • water resources
Uneingeschränkter Zugang

Restoration and assessment of water resources of drained lakes. Example of Chełmno Lakeland (Poland)

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 45 - 50

Zusammenfassung

Abstract

Based on cartographic materials, three lakes drained in the previous centuries have been reconstructed. It was found that by restoring them to their original state their total surface area would rise by 140 ha. Knowing the water surface level, determined on the basis of the range of peat soils and contour lines, the author reconstructed the bathymetric plans of the lakes. This, in turn, allowed a determination of the volume of water stored in their basins. It amounted to ca. 2.5 million m3. The approach adopted in the paper draws attention to an important element, i.e. to lakes which no longer exist in Poland and which have disappeared as a result of hydrotechnical works. Their restoration to their original state could become an important link in water retention and delaying the land phase of the water cycle. Activities aimed at retaining water in reception basins are carried out in Poland, among others, through the small retention program. Within this project, facilities such as artificial storage reservoirs are being built. In the light of the foregoing, before making a decision to build such a reservoir, it is worth considering the possibility to restore the natural components of the environment, which is more justifiable, both from the point of view of subsequent functioning of the environment and economic factors.

Schlüsselwörter

  • water resources
  • lake retention
  • drained lakes
  • Chełmo Lakeland
Uneingeschränkter Zugang

Response of cyanobacteria to the fountain-based water aeration system in Jeziorak Mały urban lake

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 51 - 60

Zusammenfassung

Abstract

This study of cyanobacteria phytoplankton was conducted from May to August in 2002, 2003 and 2005 during fountain-based water aeration in the pelagial of the Jeziorak Mały urban lake in Poland. Additional water mixing by this installation’s activity changed the cyanobacterial growth conditions. Although less of their proportion was noted in total phytoplankton abundance, higher mean abundance and biomass were recorded at the fountain than at the lake centre. Higher water temperature in the surface layer favoured cyanobacterial growth at the fountain, while higher iron concentration stimulated their development in the lake’s centre. This was supported by positive correlations between their abundance and these water parameters. Moreover, the fountain’s activity contributed to the cyanobacteria sinking in the water column. The higher abundance of cyanobacteria was found at 1m depth in May, July and August than in the fountain surface layer. Additional water mixing during fountain activity caused also a shift in their abundance maximum (C - June and F - August) and contributed to intensive organic matter decomposition. These conditions promoted cyanobacterial nutrient uptake from the water at the fountain, and this is supported by the negative correlation between their abundance and orthophosphate and total nitrogen concentrations. Generally, water mixing during the fountain’s activity does not inhibit the growth of cyanobacteria. This phenomenon disturbed abundance dynamics of the cyanobacteria in summer months but didn’t contribute to their abundance decrease. It is important for these results to be considered in future management of shallow urban lakes.

Keywords

  • lake
  • restoration
  • fountain
  • cyanobacteria
  • nutrients
6 Artikel
Uneingeschränkter Zugang

A new water energy dissipater for efficient energy dissipation and enriching the flow with dissolved oxygen content

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 3 - 11

Zusammenfassung

Abstract

One of the most important problems Egypt is facing nowadays is saving and controlling the limited available quantity of water and its quality for irrigation and other purposes. Such goals may be achieved through different types of diversion head structures across the river and in the entrance of other carrying canals. The construction of diversion head structures, which usually causes many technical problems, should have the objective of solving and overcoming to protect the structure from failure. The main problem occurs downstream. Such structures have the harmful effect of converting the potential energy gained in the upstream side to a kinetic energy in the downstream side. This energy must be dissipated shortly and safely as near as possible to the head structure to avoid its destructive effect. The hydraulic jump is the most effective tool for the dissipation of water energy, accelerating the forming of the hydraulic jump downstream such structures became essential for achieving our main goal. Using energy dissipaters on the soled apron in the downstream side of the structures was the main technique for accelerating the hydraulic jump formation and dissipating great amount of the residual harmful kinetic energy occurring downstream head structures. So early, many researchers investigated different types, shapes, and arrangements of such dissipaters to evaluate its efficiency in dissipating the water energy and accelerating the forming of the hydraulic jump. In fact, in our present study we will try to investigate some other shapes of energy dissipaters, which have not been studied enough, by evaluating its positive technical impact on: (i) percentage value of dissipating kinetic water energy; (ii) percentage value of increasing the dissolved oxygen (DO) content in the irrigation water, and improving its quality. The study is proposed to be held in the irrigation and hydraulic laboratory of the Civil department, Faculty of Engineering, Assiut University, using a movable bed tilting channel 20 m long, 30 cm wide, and 50 cm high, using fourteen types of curved dissipaters with different arrangements as shown in Table 2. It is worth mentioning that, in this first part of our paper, we will introduce a comparative analysis for the efficiency of different types of energy dissipaters available in the literature review. The most effective types of the previously studied dissipaters will be put in a comparison with our new dissipaters from the two above mentioned points of view, and the results will be presented in the second part of this paper later.

Keywords

  • energy dissipation
  • hydraulic jump
  • curved sill dissipater
  • water quality
  • dissolved oxygen
Uneingeschränkter Zugang

Phases and interruptions in postglacial development of humic lake margin (Lake Suchar Wielki, NE Poland)

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 13 - 20

Zusammenfassung

Abstract

Our study concerns the development of marginal zone of Lake Suchar Wielki (Wigry National Park). This humic lake is characterised by mire occurrence in its marginal zone, covered with a floating mat spreading on water surface. Biogenic sediments (peat archive) present in lakeside allow recognising the thousands years’ development pattern of lake surrounded by mire. The wetland records were analysed for plant macroremains, degree of peat decomposition, sediment geochemical features along with age assessment. Morphological characteristics of the catchment were integrated with the wetland records. Our research showed that after the lake origin in the Allerod, accumulation in its marginal zone was interrupted, which was probably connected with high precipitation in the past. Slope processes could be possible. Stabilisation of environmental conditions took place in the younger Holocene. Despite these perturbations marginal zone of the lake was permanently terrestrial in character, as indicated by values of atomic C:N ratio.

Keywords

  • humic lake
  • peat archive
  • hiatus
  • marginal zone of lake
  • C:N ratio
Uneingeschränkter Zugang

The structure and spatial heterogeneity of zooplankton in small lake river Wel (Poland)

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 21 - 31

Zusammenfassung

Abstract

The aim of the study was to determine changes in potamoplankton structure caused by lakes in the fluvial system of the small River Wel. The river flows through 10 lakes. The study was conducted in 2007 and 2008. The selection of sites enabled the assessment of the impact exerted by hydrological conditions of the river on zooplankton, as well as the determination of the effect of lakes situated within the river course on the analysed assemblage of organisms. In total 95 species were determined with an average abundance 1026 ind. 10 dm-3. Rotifers dominated qualitatively and quantitatively and among crustaceans - Copepods. Lakes seem to be the main source of zooplankton in the fluvial system of the Wel River. The lakes disturb the river continuum, but their impact on the structure of zooplankton is short-lived. Due to the presence of flow-through lakes along the river, species richness of zooplankton in the Wel River is similar to that in large rivers.

Schlüsselwörter

  • fluvial system
  • river continuum
  • potamoplankton
  • Rotifers
  • Cladocera
  • Copepoda
Uneingeschränkter Zugang

Changing the geometry of basins and water resources of Lakes Gopło and Ostrowskie under the influence of anthropopressure

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 33 - 43

Zusammenfassung

Abstract

The paper presents the changes that have occurred in the morphometry of Lakes Gopło and Ostrowskie, which are located in central Poland. The analysis covered the period characterised by increased human interference into the water cycle, which has been taking place continually since the mid-eighteenth century. On the basis of available cartographic materials (aerial photographs, topographic maps, bathymetric charts of the lakes) and the authors’ own field measurements digital terrain models were developed for the immediate environment of the surveyed lakes. These models, in turn, were used for measuring basic parameters characterising the external dimensions of the lakes (surface area, length and maximum width, shoreline length) and their underwater relief (volume, maximum and average depth). In addition, the selected indicators of the shape and form of the lake basins were determined. The results showed a drastic reduction of water resources of the two lakes. The basin of Lake Gopło covers only the deepest parts of the former reservoir, accounting for only 23.3% of the lake before 1772, and 32.5% of its former volume. In the case of Lake Ostrowskie the surface area and volume decreased, respectively, by 23.5% (74.9 ha) and 21.3% (6 695 000 m3). Such large changes in surface area and volume of both lakes have contributed to significant changes in other morphometric parameters and indicators. In particular, significant changes were observed in relation to such morphometric characteristics as length and maximum width, as well as average and maximum depth.

Keywords

  • cartographic analysis
  • transformation of the water cycle
  • disappearance of lakes
  • lake morphometry
  • water resources
Uneingeschränkter Zugang

Restoration and assessment of water resources of drained lakes. Example of Chełmno Lakeland (Poland)

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 45 - 50

Zusammenfassung

Abstract

Based on cartographic materials, three lakes drained in the previous centuries have been reconstructed. It was found that by restoring them to their original state their total surface area would rise by 140 ha. Knowing the water surface level, determined on the basis of the range of peat soils and contour lines, the author reconstructed the bathymetric plans of the lakes. This, in turn, allowed a determination of the volume of water stored in their basins. It amounted to ca. 2.5 million m3. The approach adopted in the paper draws attention to an important element, i.e. to lakes which no longer exist in Poland and which have disappeared as a result of hydrotechnical works. Their restoration to their original state could become an important link in water retention and delaying the land phase of the water cycle. Activities aimed at retaining water in reception basins are carried out in Poland, among others, through the small retention program. Within this project, facilities such as artificial storage reservoirs are being built. In the light of the foregoing, before making a decision to build such a reservoir, it is worth considering the possibility to restore the natural components of the environment, which is more justifiable, both from the point of view of subsequent functioning of the environment and economic factors.

Schlüsselwörter

  • water resources
  • lake retention
  • drained lakes
  • Chełmo Lakeland
Uneingeschränkter Zugang

Response of cyanobacteria to the fountain-based water aeration system in Jeziorak Mały urban lake

Online veröffentlicht: 12 Sep 2014
Seitenbereich: 51 - 60

Zusammenfassung

Abstract

This study of cyanobacteria phytoplankton was conducted from May to August in 2002, 2003 and 2005 during fountain-based water aeration in the pelagial of the Jeziorak Mały urban lake in Poland. Additional water mixing by this installation’s activity changed the cyanobacterial growth conditions. Although less of their proportion was noted in total phytoplankton abundance, higher mean abundance and biomass were recorded at the fountain than at the lake centre. Higher water temperature in the surface layer favoured cyanobacterial growth at the fountain, while higher iron concentration stimulated their development in the lake’s centre. This was supported by positive correlations between their abundance and these water parameters. Moreover, the fountain’s activity contributed to the cyanobacteria sinking in the water column. The higher abundance of cyanobacteria was found at 1m depth in May, July and August than in the fountain surface layer. Additional water mixing during fountain activity caused also a shift in their abundance maximum (C - June and F - August) and contributed to intensive organic matter decomposition. These conditions promoted cyanobacterial nutrient uptake from the water at the fountain, and this is supported by the negative correlation between their abundance and orthophosphate and total nitrogen concentrations. Generally, water mixing during the fountain’s activity does not inhibit the growth of cyanobacteria. This phenomenon disturbed abundance dynamics of the cyanobacteria in summer months but didn’t contribute to their abundance decrease. It is important for these results to be considered in future management of shallow urban lakes.

Keywords

  • lake
  • restoration
  • fountain
  • cyanobacteria
  • nutrients

Planen Sie Ihre Fernkonferenz mit Scienceendo