Water level variation at a beaver pond significantly impacts net CO<sub>2</sub> uptake of a continental bog

Abstract. The carbon (C) dynamics of northern peatlands are sensitive to hydrological changes owing to ecohydrological feedback. We quantified and evaluated the impact of water level variations in a beaver pond (BP) on the CO2 flux dynamics of an adjacent, raised Sphagnum – shrub-dominated bog in southern Canada. We applied the CoupModel to the Mer Bleue bog, where the hydrological, energy and CO2 fluxes have been measured continuously for over 20 years. The lateral flow from the bog to the BP was estimated by the hydraulic gradient between the peatland and the BP's water level and the vertical profile of peat hydraulic conductivity. The model outputs were compared with the measured hydrological components, CO2 flux and energy flux data (1998–2019). CoupModel was able to reproduce the measured data well. The simulation shows that variation in the BP water level (naturally occurring or due to management) influenced the bog net ecosystem exchange of CO2 (NEE). Over 1998–2004, the BP water level was 0.75 to 1.0 m lower than during 2017–2019. Simulated net CO2 uptake was 55 g C m−2 yr−1 lower during 1998–2004 compared to 2017–2019 when there was no BP disturbance, which was similar to the differences in measured NEE between those periods. Peatland annual NEE was well correlated with water table depth within the bog, and NEE also shows a linear relation with the water level at the BP, with a slope of −120 g CO2-C m−2 yr−1 m−1. The current modelling predicts the bog may switch from CO2 sink to source when the BP water levels drop lower than ~ 1.7 m below the peat surface at the eddy covariance tower, 250 m from the BP. This study highlights the importance of natural and human disturbances to adjacent water bodies in regulating net CO2 uptake function of northern peatlands.

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Determining Extreme Still Water Levels for Design and Planning Purposes Incorporating Sea Level Rise: Sydney, Australia

Atmosphere ◽

10.3390/atmos13010095 ◽

2022 ◽

Vol 13 (1) ◽

pp. 95

Author(s):

Phil J. Watson

Keyword(s):

Sea Level Rise ◽

Water Level ◽

Sea Level ◽

Tide Gauge ◽

Water Levels ◽

Extreme Value Analysis ◽

Tide Gauge Record ◽

Value Analysis ◽

Mean Sea Level ◽

The Impact

This paper provides an Extreme Value Analysis (EVA) of the hourly water level record at Fort Denison dating back to 1915 to understand the statistical likelihood of the combination of high predicted tides and the more dynamic influences that can drive ocean water levels higher at the coast. The analysis is based on the Peaks-Over-Threshold (POT) method using a fitted Generalised Pareto Distribution (GPD) function to estimate extreme hourly heights above mean sea level. The analysis highlights the impact of the 1974 East Coast Low event and rarity of the associated measured water level above mean sea level at Sydney, with an estimated return period exceeding 1000 years. Extreme hourly predictions are integrated with future projections of sea level rise to provide estimates of relevant still water levels at 2050, 2070 and 2100 for a range of return periods (1 to 1000 years) for use in coastal zone management, design, and sea level rise adaptation planning along the NSW coastline. The analytical procedures described provide a step-by-step guide for practitioners on how to develop similar baseline information from any long tide gauge record and the associated limitations and key sensitivities that must be understood and appreciated in applying EVA.

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The impact of improved satellite retrievals on estimates of biospheric carbon balance

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-323-2020 ◽

2020 ◽

Vol 20 (1) ◽

pp. 323-331 ◽

Cited By ~ 2

Author(s):

Scot M. Miller ◽

Anna M. Michalak

Keyword(s):

Carbon Balance ◽

Near Infrared ◽

Co2 Flux ◽

Retrieval Algorithm ◽

Co2 Uptake ◽

Near Infrared Radiation ◽

Sources And Sinks ◽

Satellite Retrievals ◽

The Impact ◽

Insight Into

Abstract. The Orbiting Carbon Observatory 2 (OCO-2) is NASA's first satellite dedicated to monitoring CO2 from space and could provide novel insight into CO2 fluxes across the globe. However, one continuing challenge is the development of a robust retrieval algorithm: an estimate of atmospheric CO2 from satellite observations of near-infrared radiation. The OCO-2 retrievals have undergone multiple updates since the satellite's launch, and the retrieval algorithm is now on its ninth version. Some of these retrieval updates, particularly version 8, led to marked changes in the CO2 observations, changes of 0.5 ppm or more. In this study, we evaluate the extent to which current OCO-2 observations can constrain monthly CO2 sources and sinks from the biosphere, and we particularly focus on how this constraint has evolved with improvements to the OCO-2 retrieval algorithm. We find that improvements in the CO2 retrieval are having a potentially transformative effect on satellite-based estimates of the global biospheric carbon balance. The version 7 OCO-2 retrievals formed the basis of early inverse modeling studies using OCO-2 data; these observations are best equipped to constrain the biospheric carbon balance across only continental or hemispheric regions. By contrast, newer versions of the retrieval algorithm yield a far more detailed constraint, and we are able to constrain CO2 budgets for seven global biome-based regions, particularly during the Northern Hemisphere summer when biospheric CO2 uptake is greatest. Improvements to the OCO-2 observations have had the largest impact on glint-mode observations, and we also find the largest improvements in the terrestrial CO2 flux constraint when we include both nadir and glint data.

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The Role of Mean Sea Level Annual Cycle on Extreme Water Levels Along European Coastline

Remote Sensing ◽

10.3390/rs12203419 ◽

2020 ◽

Vol 12 (20) ◽

pp. 3419

Author(s):

Tomás Fernández-Montblanc ◽

Jesús Gómez-Enri ◽

Paolo Ciavola

Keyword(s):

Water Level ◽

Sea Level ◽

North Sea ◽

Extreme Events ◽

Annual Cycle ◽

Coastal Flooding ◽

Water Levels ◽

Total Water ◽

Mean Sea Level ◽

The Impact

The knowledge of extreme total water levels (ETWLs) and the derived impact, coastal flooding and erosion, is crucial to face the present and future challenges exacerbated in European densely populated coastal areas. Based on 24 years (1993–2016) of multimission radar altimetry, this paper investigates the contribution of each water level component: tide, surge and annual cycle of monthly mean sea level (MMSL) to the ETWLs. It focuses on the contribution of the annual variation of MMSL in the coastal flooding extreme events registered in a European database. In microtidal areas (Black, Baltic and Mediterranean Sea), the MMSL contribution is mostly larger than tide, and it can be at the same order of magnitude of the surge. In meso and macrotidal areas, the MMSL contribution is <20% of the total water level, but larger (>30%) in the North Sea. No correlation was observed between the average annual cycle of monthly mean sea level (AMMSL) and coastal flooding extreme events (CFEEs) along the European coastal line. Positive correlations of the component variance of MMSL with the relative frequency of CFEEs extend to the Central Mediterranean (r = 0.59), North Sea (r = 0.60) and Baltic Sea (r = 0.75). In the case of positive MMSL anomalies, the correlation expands to the Bay of Biscay and northern North Atlantic (at >90% of statistical significance). The understanding of the spatial and temporal patterns of a combination of all the components of the ETWLs shall improve the preparedness and coastal adaptation measures to reduce the impact of coastal flooding.

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Explicit Finite Element Study of Liquid Sloshing Behavior in Fluid-Structure Interaction Condition

Volume 7: Fluids Engineering ◽

10.1115/imece2017-70832 ◽

2017 ◽

Author(s):

Shuo Yang ◽

Raymond K. Yee

Keyword(s):

Finite Element ◽

Water Level ◽

Similarity Theory ◽

Fluid Structure Interaction ◽

Water Levels ◽

Tank Wall ◽

Fluid Structure ◽

Structure Interaction ◽

Sloshing Phenomenon ◽

The Impact

As a common phenomenon in liquid motions, sloshing usually happens in a partially filled liquid tank of moving vehicle or structure. The objectives of this paper are to study sloshing behavior in rigid tank and deformable tank, and to develop a better performance baffle design in the tank under seismic excitations. The tank is surged with a sinusoidal oscillation about horizontal x-direction. The hydro-elasticity effect of sloshing pressure on the tank wall was taken into consideration due to the fluid-structure interaction between impact pressures and tank structures. ABAQUS finite element program using Coupled Eulerian-Lagrangian (CEL) technique was employed to simulate fluid sloshing. The sloshing phenomenon was studied in rigid tank and deformable tank models with three different water levels, and the effect of wall thickness of the deformable tank on sloshing behavior was discussed. One way to minimize the effect of sloshing in a tank, baffles are used and installed in the middle of the tank, and then various heights and material types of baffle were evaluated. The simulation results show that higher water level case creates greater pressure impact on the tank wall than lower water level case, and the elasticity of the tank structure would reduce the impact pressure of the wall. For the simulation tank model with size of 1m (H) × 1m (W) × 0.2m (D), better performance baffle was found to be the one with the height of 0.35m and was made of acrylic material. Moreover, the conclusion of this study can be extrapolated to other dimensions of the model based on similarity theory. This paper also can serve as an aid in further studying sloshing phenomenon. The findings of this study can be applied to restrain or minimize sloshing motions inside a tank.

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Monitoring Temporal Change of River Islands in the Yangtze River by Remotely Sensed Data

Water ◽

10.3390/w10101484 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1484 ◽

Cited By ~ 1

Author(s):

Jinyan Sun ◽

Lei Ding ◽

Jiaze Li ◽

Haiming Qian ◽

Mengting Huang ◽

...

Keyword(s):

Water Level ◽

Yangtze River ◽

Temporal Change ◽

Flood Disaster ◽

Water Levels ◽

Sediment Supply ◽

The Yangtze River ◽

Flood Warning ◽

River Islands ◽

The Impact

The spatial extent and area of river islands are always changing due to the impact of hydrodynamic conditions, sediment supply and human activities. A catastrophic flood disaster was driven by sustained and heavy rainfall around the middle and lower Yangtze River in 18 June to 21 July 2016. The flood resulted in the most serious social-economic loss since 1954 and caused a larger-scale inundation for a short time. It is essential to continuously monitor the dynamics changes of river islands because this can avoid frequent field measurements in river islands before and after flood disasters, which are helpful for flood warning. This paper focuses on the temporal change of three river islands called Fenghuangzhou, Changshazhou, and one uninhabited island in the Yangtze River in 2016. In this study, GF-1 (GaoFen-1) WFV (wide field view) data was used for our study owing to its fine spatial and temporal resolution. A simple NDWI (Normalized Difference Water Index) method was used for the river island mapping. Human checking was then performed to ensure mapping accuracy. We estimated the relationship between the area of river islands and measured water levels using four models. Furthermore, we mapped the spatial pattern of inundation risk of river islands. The results indicate a good ability of the GF-1 WFV data with a 16-m spatial resolution to characterize the variation of river islands and to study the association between flood disaster and river islands. A significantly negative but nonlinear relationship between the water level and the area of the river island was observed. We also found that the cubic function fits best among three models (R2 > 0.8, P < 0.001). The maximum of the inundated area at the river island appeared in the rainy season on 8 July 2016 and the minimum occurred in the dry season on 28 December 2016, which is consistent with the water level measured by the hydrological station. Our results derived from GF-1 data can provide a useful reference for decision-making of flood warning, disaster assessment, and post-disaster reconstruction.

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From pristine to present state: hydrology evolution of Lake Saint-François, St. Lawrence River

Canadian Journal of Civil Engineering ◽

10.1139/l98-019 ◽

1998 ◽

Vol 25 (5) ◽

pp. 864-879 ◽

Cited By ~ 15

Author(s):

Jean Morin ◽

Michel Leclerc

Keyword(s):

Water Level ◽

Plant Biomass ◽

Seasonal Pattern ◽

Water Levels ◽

Ship Traffic ◽

Water Level Rise ◽

Hydropower Production ◽

Discharge Regulation ◽

The Impact ◽

St Lawrence River

Lake Saint-François is a relatively shallow fluvial lake of the St. Lawrence River with numerous deep channels. This complex system has been considerably altered from its pristine state 150 years ago. Currently, the water level is stabilized and the flow is regulated; important areas have been dredged and the major part of its outflow is diverted through the Beauharnois canal. The evolution of water levels shows a trend towards stabilization as required for ship traffic in the St. Lawrence Seaway and for hydropower production. With the construction of the Moses-Saunders dam in 1960, the flow of the river could be regulated; changes occur in the seasonal pattern of the flow. Ancient stage-discharge relationships were recreated to describe the impact of the 1849 damming and of the present level stabilization. Stabilization of the water level has favored the growth of submerged plants. Manning's friction coefficient was used to show that plant biomass has doubled since 1920; the onset of biomass increases corresponds to a water level stabilization event. The distribution of wetlands in the Lake Saint-François area was drastically modified by the water level rise caused by the 1849 damming. New wetlands were created and pre-1849 wetlands, located on what are currently shoals in the central part of the lake, have totally disappeared.Key words: Lake Saint-François, St. Lawrence River, impact of civil works, flow discharge regulation, water level regulation, wetland flooding cycle, submerged macrophyte, ecosystem reaction, civil work history.

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Hydrometeorological drivers of flood characteristics in the Brahmaputra river basin in Bangladesh

10.5194/hess-2021-97 ◽

2021 ◽

Author(s):

Sazzad Hossain ◽

Hannah L. Cloke ◽

Andrea Ficchì ◽

Andrew G. Turner ◽

Elisabeth M. Stephens

Keyword(s):

Water Level ◽

Morphological Changes ◽

High Water ◽

Water Levels ◽

Future Climate Change ◽

South Asian Summer Monsoon ◽

Large Variability ◽

Long Duration ◽

The Impact ◽

Flood Characteristics

Abstract. While flooding is an annual occurrence in the Brahmaputra basin during the South Asian summer monsoon, there is large variability in the flood characteristics that drive risk: flood duration, rate of water level rise and peak water level. The aim of this study is to understand the key hydrometeorological drivers influencing these flood characteristics. We analyse hydrometeorological time series of the last 33 years to understand flood dynamics focusing on three extraordinary floods in 1998 (long duration), 2017 (rapid rise) and 2019 (high water level). We find that long duration floods in the basin have been driven by basin-wide seasonal rainfall extremes associated with the development phase of strong La Niña events, whereas floods with a rapid rate of rise have been driven by more localized rainfall falling in a hydrological ‘sweet spot’ that leads to a concurrent contribution from the tributaries into the main stem of the river. We find that recent record high water levels are not coincident with extreme river flows, hinting that sedimentation and morphological changes are also important drivers of flood risk that should be further investigated. Understanding these drivers is essential for flood forecasting and early warning and also to study the impact of future climate change on flood.

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Water Level Fluctuations in the Turawa Reservoir in Relation to the Tourist Use of the Water Body

Miscellanea Geographica ◽

10.2478/mgrsd-2008-0013 ◽

2008 ◽

Vol 13 (1) ◽

pp. 133-144

Author(s):

Andrzej T. Jankowski ◽

Marek Ruman

Keyword(s):

Water Level ◽

Water Body ◽

High Water ◽

Ecological Condition ◽

Water Levels ◽

Water Level Fluctuations ◽

Natural Factors ◽

Odra River ◽

The Impact ◽

First Time

Abstract The aim of the paper is to assess the fluctuations of water levels in the Turawa Reservoir (50° 43’ N, 18° 08’ E) in relation to the tourist use of the water body. The reservoir is situated within the macroregion of the Silesian Lowland in the mesoregion of the Opole Plain. In administrative terms, the reservoir is situated in the pole Province within the borough of Turawa. In hydrological terms, in turn, it is situated in the catchment area of the Mała Panew river, which belongs to the basin of the Odra river. The Turawa Reservoir was opened for use in 1938, and in 1948 it was filled with water to its maximum for the first time. At present, the surface area of the reservoir, when it is filled with water to its maximum, is about 20.8 km2, its volume 99.5 mln m3, and its depth exceeds 13 meters. In the period of hydrological years 1976-2000 water levels in this reservoir were characterized by high, unnoticed in natural conditions, amplitudes of changes reaching 6.99 m. Anthropogenically stimulated fluctuations in the water level result in conflicts in terms of tasks and functions that the Turawa Reservoir was designed for. Changes in the level of the water surface in the Turawa Reservoir resulted from the impact of the natural factors (thaw and rainfall related high water levels), as well as anthropogenic ones (the need to improve sailing conditions, water supply for industrial and municipal needs). Decreasing the fluctuations of water levels in the Turawa Reservoir is necessary in order to maintain its tourist-recreational functions and keep the ecological condition of its waters at the appropriate level.

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Deformation and stability analyses of a near-dam rocky slope and its potential landslide-generated wave threats

Quarterly Journal of Engineering Geology and Hydrogeology ◽

10.1144/qjegh2021-018 ◽

2021 ◽

pp. qjegh2021-018

Author(s):

Ming-liang Chen ◽

Xing-guo Yang ◽

Shun-chao Qi ◽

Hai-bo Li ◽

Jia-wen Zhou

Keyword(s):

Water Level ◽

Rock Slope ◽

Limit Equilibrium ◽

Water Levels ◽

Reservoir Rock ◽

Water Diversion ◽

Reservoir Water ◽

Reservoir Water Level ◽

The Impact

Occurrence of a reservoir landslide and its potential secondary hazards near a dam can result in significant losses and casualties, such as those that resulted from the Vajont landslide. In this study, a cataclinal rock slope in the Maoergai reservoir was taken as a case to study the characteristics of the gravitational deformation process and to analyze the potential threat. The stability of rock slope is analyzed by the limit equilibrium method, and the potential landslide movement and subsequent waves are also simulated. Results indicate that lithology, geological structure, reservoir water level changes and artificial activities all play an important role for the large deformation of rock slope deformation, which is characterized by a combination of bending-toppling and principally shear-slip. Pre-calculations of potential threats indicated that the impact of a landslide wave would be greater at dead water levels than at the normal water level and could result in blockage of the inlet to the water diversion structure on the opposite right bank. These findings provide implication for the control of reservoir rock slopes: (i) serious attention should be paid to the influence of water on rock strength in early and (ii) infiltration must be prevented during water level rise.Thematic collection: This article is part of the Role of water in destabilizing slopes collection available at: https://www.lyellcollection.org/cc/Role-of-water-in-destabilizing-slopes

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Changing Water Levels in Lake Superior, MI (USA) Impact Periphytic Diatom Assemblages in the Keweenaw Peninsula

Water ◽

10.3390/w13030253 ◽

2021 ◽

Vol 13 (3) ◽

pp. 253

Author(s):

M. Megan Woller-Skar ◽

Alexandra Locher ◽

Ellen Audia ◽

Evan W. Thomas

Keyword(s):

Water Level ◽

Surface Area ◽

Lake Superior ◽

Water Levels ◽

Ecological Processes ◽

Periphyton Community ◽

Water Level Changes ◽

Community Assemblages ◽

Keweenaw Peninsula ◽

The Impact

Predicted climate-induced changes in the Great Lakes include increased variability in water levels, which may shift periphyton habitat. Our goal was to determine the impacts of water level changes in Lake Superior on the periphyton community assemblages in the Keweenaw Peninsula with different surface geology. At three sites, we identified periphyton assemblages as a function of depth, determined surface area of periphyton habitat using high resolution bathymetry, and estimated the impact of water level changes in Lake Superior on periphyton habitat. Our results suggest that substrate geology influences periphyton community assemblages in the Keweenaw Peninsula. Using predicted changes in water levels, we found that a decrease in levels of 0.63 m resulted in a loss of available surface area for periphyton habitat by 600 to 3000 m2 per 100 m of shoreline with slopes ranging 2 to 9°. If water levels rise, the surface area of substrate will increase by 150 to 370 m2 per 100 m of shoreline, as the slopes above the lake levels are steeper (8–20°). Since periphyton communities vary per site, changes in the surface area of the substrate will likely result in a shift in species composition, which could alter the structure of aquatic food webs and ecological processes.

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