Influence of Water Level Drawdown on the Fish Populations of Cross Lake, Manitoba

1984 ◽  
Vol 41 (1) ◽  
pp. 118-125 ◽  
Author(s):  
M. N. Gaboury ◽  
J. W. Patalas
Keyword(s):  
Water Level ◽  
Hatching Success ◽  
Northern Pike ◽  
Water Levels ◽  
Coregonus Clupeaformis ◽  
Spawning Areas ◽  
Influence Of Water ◽  
Coregonus Artedii ◽  
Water Volumes ◽  
Coregonid Fishes

Regulated discharges into Cross Lake, Manitoba, resulted in average summer water volumes in 1980 and 1981 that were 49% lower than preregulated volumes. Water level drawdown in the summer reduces the amount of available habitat. Consequently, the standing crops of lake whitefish (Coregonus clupeaformis), walleye (Stizostedion vitreum vitreum), northern pike (Esox lucius), and Cisco (Coregonus artedii) are lower now than in preregulation and early postregulation years. Unusually early and rapid drawdown in March 1981 resulted in a severe winterkill, causing a substantial decrease in catches per unit of effort (CPUE) for most species from 1980 to 1981. The most affected species were whitefish and cisco, which showed a 50% reduction in CPUE from 1980 to 1981. The amount of fall to late spring drawdown and the year-class strengths of coregonid fishes were inversely related. A marked overwinter drawdown reduces whitefish and cisco hatching success apparently by dewatering their spawning areas and desiccating the eggs. Low water levels in spring prevented pike and walleye access to spawning areas.

Identification of Diphyllobothrium dendriticum and Diphyllobothrium latum from some freshwater fishes of central Canada

1985 ◽  
Vol 63 (1) ◽  
pp. 196-201 ◽  
Author(s):  
T. A. Dick ◽  
B. C. Poole
Keyword(s):  
Seminal Vesicle ◽  
Northern Pike ◽  
Larus Argentatus ◽  
Coregonus Clupeaformis ◽  
Neck Length ◽  
Herring Gulls ◽  
Diphyllobothrium Dendriticum ◽  
Central Canada ◽  
Coregonus Artedii ◽  
Diphyllobothrium Latum

Two species of Diphyllobothrium occurred in Quigly Lake, Manitoba: plerocercoids of D. dendriticum encapsulated on the viscera of shallow water cisco (Coregonus artedii) and lake whitefish (Coregonus clupeaformis) and plerocercoids of D. latum unencapsulated in the muscle of walleye (Stizostedion vitreum vitreum) and northern pike (Esox lucius). Adult D. dendriticum were obtained through experimental infections of both herring gulls (Larus argentatus) and hamsters (Mesocricetus auratus), but adult D. latum developed experimentally only in the latter. The scolex position of adult D. dendriticum was more anterior than D. latum in the small intestine of hamsters. Eggs were present in utero and in the faeces by days 10–11 postinfection (PI) for D. dendriticum in hamsters and gulls and by day 17 PI for D. latum in hamsters. Adult D. dendriticum grew longer and had more segments in gulls than in hamsters. The neck length of adult D. latum was at least five times greater than the neck length of adult D. dendriticum in hamsters by day 17 PI. Viewed laterally, the seminal vesicle in adult D. dendriticum was dorsal to the cirrus sac, while in D. latum, the seminal vesicle was dorsocaudal to the cirrus sac. A constriction between segments was noted for adult D. latum only.

scholarly journals Estimation of the influence of water exchange with the sea conditions on the water level and salinity variability in the Tyligulskyi Liman lagoon

2017 ◽  
pp. 232-241 ◽  
Author(s):  
Yu. S. Tuchkovenko ◽  
D. V. Kushnir ◽  
N. S. Loboda
Keyword(s):  
Water Level ◽  
Climatic Conditions ◽  
Water Levels ◽  
Water Salinity ◽  
Management Activity ◽  
Salinity Variability ◽  
Effective Option ◽  
Influence Of Water ◽  
Long Term Trend

The potentialities of averting a further salinization of the Tyligulskyi Liman lagoon were identified on the basis of the results of the hydrodynamic modelling, using the numerical model Delft3D-FLOW. The means to prevent the salinization in the lagoon include a reconstruction of the “lagoon-sea” interconnecting channel and the changing of its operational schedule, as well as the increasing of the river inflow considering the climatic conditions of the first half of the XXI century. The results of the verification of the hydrodynamic model are given. It is shown that for stabilizing water levels and reducing the rate of the water salinity in the lagoon the most effective option is the year-round operation of the deepened “lagoon-sea” connecting channel. This will be facilitated by a multi-directional exchange of water through the channel caused by wind-induced water level oscillations in the lagoon and in the sea. However, while maintaining the current level of the water management activity in the catchment area of the lagoon, a long-term trend of increasing water salinity in the lagoon still remains. Only the restoration of natural river discharge into the lagoon could reduce the tendency of growing water salinity to a minimum.

Water Level Regulations and Fisheries in Rainy Lake and the Namakan Reservoir

1993 ◽  
Vol 50 (9) ◽  
pp. 1934-1945 ◽  
Author(s):  
Yosef Cohen ◽  
Paul Radomski
Keyword(s):  
Water Level ◽  
Interspecific Interactions ◽  
Water Levels ◽  
Fish Populations ◽  
Coregonus Clupeaformis ◽  
Spawning Habitat ◽  
Emergent Macrophytes ◽  
Dry Spells ◽  
The Difference ◽  
Yearly Maximum

The difference between the yearly maximum and minimum water levels (YMXR) is an index of lake dynamics: shoals are exposed and inundated, nutrients are oxidized and reduced, and the diversity and density of the aquatic plant community are affected. Shoals and emergent macrophytes provide spawning habitat for fish. The 5-yr moving variance of YMXR fluctuates regularly with periods of about 11.2 yr (periodicity of sunspot cycles). This reflects the effects of within-year consecutive periods of storms and dry spells. Water level regulations resulted in changes in both amplitudes and frequencies of YMXR compared with natural fluctuations. We established links between fluctuations in YMXR and fluctuations in fish populations. Water level regulations, through their effects on YMXR, corresponded to changes in interspecific interactions on Rainy Lake and the Namakan Reservoir. In both, walleye's (Stizostedion vitreum) fluctuations were synchronized with both those of lake whitefish (Coregonus clupeaformis) and northern pike (Esox lucius) more than those of either species with the other two. On the Namakan Reservoir, YMXR fluctuations were accentuated by water level regulation; on Rainy Lake, they were dampened. Regulations should consider frequencies and amplitudes of changes in water level and their effect on fish populations.

AUTOMATIC WATER LEVEL MONITORING WITH IOT AND LPWAN

2019 ◽  
pp. 95-103
Author(s):  
Krum Videnov ◽  
Vanya Stoykova
Keyword(s):  
Water Level ◽  
Real Time ◽  
Early Warning ◽  
Water Sources ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Level Monitoring ◽  
Water Level Monitoring

Monitoring water levels of lakes, streams, rivers and other water basins is of essential importance and is a popular measurement for a number of different industries and organisations. Remote water level monitoring helps to provide an early warning feature by sending advance alerts when the water level is increased (reaches a certain threshold). The purpose of this report is to present an affordable solution for measuring water levels in water sources using IoT and LPWAN. The assembled system enables recording of water level fluctuations in real time and storing the collected data on a remote database through LoRaWAN for further processing and analysis.

Interaction between water pressure in the basal drainage system and discharge from an Alpine glacier before and during a rainfall-induced subglacial hydrological event

1997 ◽  
Vol 24 ◽  
pp. 288-292 ◽  
Author(s):  
Andrew P. Barrett ◽  
David N. Collins
Keyword(s):  
Water Level ◽  
Water Pressure ◽  
Drainage System ◽  
Water Levels ◽  
Drainage Network ◽  
Alpine Glacier ◽  
Hydraulic Conditions ◽  
Borehole Water ◽  
Progressive Growth ◽  
Resultant Increase

Combined measurements of meltwater discharge from the portal and of water level in a borehole drilled to the bed of Findelengletscher, Switzerland, were obtained during the later part of the 1993 ablation season. A severe storm, lasting from 22 through 24 September, produced at least 130 mm of precipitation over the glacier, largely as rain. The combined hydrological records indicate periods during which the basal drainage system became constricted and water storage in the glacier increased, as well as phases of channel growth. During the storm, water pressure generally increased as water backed up in the drainage network. Abrupt, temporary falls in borehole water level were accompanied by pulses in portal discharge. On 24 September, whilst borehole water level continued to rise, water started to escape under pressure with a resultant increase in discharge. As the drainage network expanded, a large amount of debris was flushed from a wide area of the bed. Progressive growth in channel capacity as discharge increased enabled stored water to drain and borehole water level to fall rapidly. Possible relationships between observed borehole water levels and water pressures in subglacial channels are influenced by hydraulic conditions at the base of the hole, distance between the hole and a channel, and the nature of the substrate.

scholarly journals Spatial distribution of water level impact to back-barrier bays

2018 ◽  
Author(s):  
Alfredo L. Aretxabaleta ◽  
Neil K. Ganju ◽  
Zafer Defne ◽  
Richard P. Signell
Keyword(s):  
Water Level ◽  
Sea Level ◽  
Water Levels ◽  
Analytical Models ◽  
Barnegat Bay ◽  
Sea Level Fluctuations ◽  
Flooding Hazard ◽  
Short Period ◽  
Inlet Geometry ◽  
Spatial Estimates

Abstract. Water level in semi-enclosed bays, landward of barrier islands, is mainly driven by offshore sea level fluctuations that are modulated by bay geometry and bathymetry, causing spatial variability in the ensuing response (transfer). Local wind setup can have a secondary role that depends on wind speed, fetch, and relative orientation of the wind direction and the bay. Inlet geometry and bathymetry primarily regulate the magnitude of the transfer between open ocean and bay. Tides and short-period offshore oscillations are more damped in the bays than longer-lasting offshore fluctuations, such as storm surge and sea level rise. We compare observed and modeled water levels at stations in a mid-Atlantic bay (Barnegat Bay) with offshore water level proxies. Observed water levels in Barnegat Bay are compared and combined with model results from the Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST) modeling system to evaluate the spatial structure of the water level transfer. Analytical models based on the dimensional characteristics of the bay are used to combine the observed data and the numerical model results in a physically consistent approach. Model water level transfers match observed values at locations inside the Bay in the storm frequency band (transfers ranging from 70–100 %) and tidal frequencies (10–55 %). The contribution of frequency-dependent local setup caused by wind acting along the bay is also considered. The approach provides transfer estimates for locations inside the Bay where observations were not available resulting in a complete spatial characterization. The approach allows for the study of the Bay response to alternative forcing scenarios (landscape changes, future storms, and rising sea level). Detailed spatial estimates of water level transfer can inform decisions on inlet management and contribute to the assessment of current and future flooding hazard in back-barrier bays and along mainland shorelines.

scholarly journals The effects of ENSO, climate change and human activities on the water level of Lake Toba, Indonesia: a critical literature review

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hendri Irwandi ◽  
Mohammad Syamsu Rosid ◽  
Terry Mart
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Human Activities ◽  
Southern Oscillation ◽  
Climatic Conditions ◽  
Water Levels ◽  
Dominant Factor ◽  
Climate Projections ◽  
Continuous Increase ◽  
The Future

AbstractThis research quantitatively and qualitatively analyzes the factors responsible for the water level variations in Lake Toba, North Sumatra Province, Indonesia. According to several studies carried out from 1993 to 2020, changes in the water level were associated with climate variability, climate change, and human activities. Furthermore, these studies stated that reduced rainfall during the rainy season due to the El Niño Southern Oscillation (ENSO) and the continuous increase in the maximum and average temperatures were some of the effects of climate change in the Lake Toba catchment area. Additionally, human interventions such as industrial activities, population growth, and damage to the surrounding environment of the Lake Toba watershed had significant impacts in terms of decreasing the water level. However, these studies were unable to determine the factor that had the most significant effect, although studies on other lakes worldwide have shown these factors are the main causes of fluctuations or decreases in water levels. A simulation study of Lake Toba's water balance showed the possibility of having a water surplus until the mid-twenty-first century. The input discharge was predicted to be greater than the output; therefore, Lake Toba could be optimized without affecting the future water level. However, the climate projections depicted a different situation, with scenarios predicting the possibility of extreme climate anomalies, demonstrating drier climatic conditions in the future. This review concludes that it is necessary to conduct an in-depth, comprehensive, and systematic study to identify the most dominant factor among the three that is causing the decrease in the Lake Toba water level and to describe the future projected water level.

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