Influence of morphometric parameters and meteorological conditions on ephemeral pool hydrology in the Canadian Shield forest 

2021 ◽  
Author(s):  
Marjolaine Roux ◽  
Marie Larocque ◽  
Philippe Nolet ◽  
Sylvain Gagné
Keyword(s):  
Surface Water ◽  
Water Level ◽  
Meteorological Conditions ◽  
Canadian Shield ◽  
Water Levels ◽  
Forest Biodiversity ◽  
Rainfall Events ◽  
Ephemeral Pools ◽  
Water Level Variations ◽  
Dry Out

<p>Ephemeral pools are geographically isolated wetlands commonly found in temperate forests of northeastern North America. These wetlands are usually hydrologically isolated from the surface water network but in some conditions can be connected to local groundwater flow. They fill at maximal capacity following spring snowmelt and dry out during summer. They contribute to forest biodiversity by providing breeding habitats for amphibians during their spring and early summer period of hydrological activity. However, ephemeral pools are poorly understood and rarely studied because of their small dimensions and temporary hydrology. This work presents the final results of a five-year study aimed to acquire new knowledge on ephemeral pool hydrology to go beyond the anecdotical pool and to understand the conditions and processes that driving their hydrology. A large number of pools (39) located in the Canadian Shield forest were instrumented to monitor hourly water level variations in the pool and in the neighboring and underlying fractured bedrock aquifer. They were also described in extensive details for their geomorphological features and water levels over a period from one to five years (April 2016 to July 2020). The first rather surprising result from this work is that, although the pools are all located in bedrock depressions, they cover a wide range of morphologies. Their maximum sizes vary from 29 to 1866 m<sup>2</sup> and their maximal volumes vary from 4 to 654 m<sup>3</sup>. Their maximum water depths are also highly contrasted, ranging from 0.14 m to 2.03 m. The pool depressions are overlain by mineral sediments (silt to fine sand with occurrences of coarse sand and gravel) of contrasted thicknesses (0 m to 1.70 m). An organic matter layer of highly varying thickness (0.12 m to 1.24 m) was observed at all sites above the mineral sediments. Despite these varied morphological conditions, all the pools have similar hydrological patterns throughout the year and these patterns are highly resilient to meteorological conditions. They dry out between the end of May and the end of July, rapid temporary refilling during important summer rainfall events, and partially refilling in autumn following more frequent rainfall events and lower evapotranspiration. The results show that surface water levels are maintained when the underlying sediments are saturated. Otherwise, the ephemeral pools lose water by infiltration to the underlying aquifer. Water level variations within the pools are positively and significantly correlated with net precipitation (P – PET). Hydroperiods vary between 28 days (2020) and 86 days (2017), reflecting the year-to-year meteorological variability. The mean hydroperiod is significantly correlated to spring rainfall (April to June), but also to the volume of water stored in the pool, and to the pool surface area. This study provides a unique and original dataset that contribute to better understand the hydrodynamics and resilience to anthropogenic (forestry) and natural (climate change) impacts of a wetland type that is rarely studied but provide crucial habitats for forest biodiversity.</p>

scholarly journals Analysis of water level variations in the Huangzhuang reach (Hanjiang River, China) during recent years

2020 ◽  
Vol 383 ◽  
pp. 25-30
Author(s):  
Xiao Xiao ◽  
Beiping Mao ◽  
Bao Qian
Keyword(s):  
Surface Water ◽  
Water Level ◽  
Flood Control ◽  
Discharge Rate ◽  
Water Levels ◽  
Bridge Engineering ◽  
High Discharge ◽  
Water Level Variations ◽  
River Deposits ◽  
Hanjiang River

Abstract. The 2017 Hanjiang autumn flood appeared to have higher surface water levels at the same discharge rate than previously at the Huangzhuang gauging station. It is seriously impacted the flood control. This paper analyses the 2000–2017 data from the Huangzhuang reach in the Hanjiang River, including surface water levels, the surface water fall, erosion-deposition variation and the engineering activities. A comparison of the 2016–2017 data with the 2000–2015 data in the Huangzhuang reach, revealed that the surface water levels were about 1.47 and 0.13 m higher in the high and intermediate discharge ranges, respectively. In the low discharge range, the 2016–2017 and 2010–2015 surface water levels were similar. However, a comparison of the 2016–2017 with the 2000–2009 data in the low discharge range, shows that the surface water levels were 0.28–0.4 m lower. The surface water fall in the Zhuandouwan–Huangzhuang's reach decreased in 2016–2017 for discharges above 5000 m3 s−1, whereas in the Huangzhuang–Datong reach the opposite was found. For other time periods and discharge ranges the fall decreased. In the Datong-Shayang reach the fall reduced in 2014–2015 relative to other periods in 2000–2017 in the discharge range above 5000 m3 s−1. The erosion-silting analysis for the Huangzhuang reach showed scouring of local river deposits due to bridge engineering. However, near the bridge the substantial silting was found. The collated surface water level and scouring-silting data suggest that reduced surface water levels during low discharge are mainly due to the overall river erosion. The increased surface levels in the high discharge range are due to local river siltation, especially because of the increased water resistance as response to bridge engineering.

scholarly journals Dynamics of fortnightly water level variations along a tide-dominated estuary with negligible river discharge

2021 ◽  
Author(s):  
Erwan Garel ◽  
Ping Zhang ◽  
Huayang Cai
Keyword(s):  
Water Level ◽  
Phase Difference ◽  
River Discharge ◽  
Water Levels ◽  
Level Increase ◽  
Upstream Direction ◽  
Water Level Variations ◽  
Mean Water Level ◽  
The Mean ◽  
Guadiana Estuary

Abstract. Observations indicate that the fortnightly fluctuations in mean water level increase in amplitude along the lower half of a tide-dominated estuary (The Guadiana estuary) with negligible river discharge but remain constant upstream. Analytical solutions reproducing the semi-diurnal wave propagation shows that this pattern results from reflection effects at the estuary head. The phase difference between velocity and elevation increases from the mouth to the head (where the wave has a standing nature) as the high and low water levels get progressively closer to slack water. Thus, the tidal (flood-ebb) asymmetry in discharge is reduced in the upstream direction. It becomes negligible along the upper estuary half, as the mean sea level remains constant despite increased friction due to wave shoaling. Observations of a flat mean water level along a significant portion of an upper estuary, easier to obtain than the phase difference, can therefore indicate significant reflection of the propagating semi-diurnal wave at the head. Details of the analytical model shows that changes in the mean depth or length of semi-arid estuaries, in particular for macrotidal locations, affect the fortnightly tide amplitude, and thus the upstream mass transport and inundation regime. This has significant potential impacts on the estuarine environment.

scholarly journals Feedback Mechanism in Bifurcating River Systems: the Effect on Water-Level Sensitivity

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1915
Author(s):  
Matthijs R.A. Gensen ◽  
Jord J. Warmink ◽  
Fredrik Huthoff ◽  
Suzanne J.M.H. Hulscher
Keyword(s):  
Water Level ◽  
Flood Risk ◽  
River System ◽  
Feedback Mechanism ◽  
Water Levels ◽  
River Systems ◽  
Water Level Variations ◽  
System Water ◽  
Discharge Distribution ◽  
Single Branch

Accurate and reliable estimates of water levels are essential to assess flood risk in river systems. In current practice, uncertainties involved and the sensitivity of water levels to these uncertainties are studied in single-branch rivers, while many rivers in deltas consist of multiple distributaries. In a bifurcating river, a feedback mechanism exists between the downstream water levels and the discharge distribution at the bifurcation. This paper aims to quantify the sensitivity of water levels to main channel roughness in a bifurcating river system. Water levels are modelled for various roughness scenarios under a wide range of discharge conditions using a one-dimensional hydraulic model. The results show that the feedback mechanism reduces the sensitivity of water levels to local changes of roughness in comparison to the single-branch river. However, in the smaller branches of the system, water-level variations induced by the changes in discharge distribution can exceed the water-level variations of the single-branch river. Therefore, water levels throughout the entire system are dominated by the conditions in the largest branch. As the feedback mechanism is important, the river system should be considered as one interconnected system in river maintenance of rivers, flood-risk analyses, and future planning of river engineering works.

scholarly journals Daily water-level variations of supraglacial lakes in the southern Inylchek Glacier, Central Asia

2020 ◽  
Author(s):  
Naoki Sakurai ◽  
Chiyuki Narama ◽  
Mirlan Daiyrov ◽  
Muhammed Esenamanov ◽  
Zarylbek Usekov ◽  
...  
Keyword(s):  
Water Level ◽  
Drainage Water ◽  
Water Levels ◽  
Supraglacial Lakes ◽  
Surface Models ◽  
Increase Rate ◽  
Aerial Vehicle ◽  
Water Level Variations ◽  
Daily Water ◽  
Lake Drainage

Abstract. To better understand the storage in and drainage through supraglacial lakes and englacial conduits, we investigated the daily water-level variations of supraglacial lakes on the southern Inylchek Glacier in Kyrgyzstan. To examine these variations, we used daily aerial digital images over three years (22 July–15 August 2017, 8–29 July 2018, and 12–19 July 2019) from an unmanned aerial vehicle (UAV) that were converted to digital surface models (DSMs) and ortho-images. Our main results are as follows. 1) When one lake drained, the water levels of other lakes might simultaneously increase, indicating that drainage water is shared with several lakes through a main englacial conduit. In one drainage event, a branch englacial conduit clearly connected to a main englacial conduit. 2) Sometimes, several lakes discharged simultaneously, indicating that several lakes had connected to a main englacial conduit that had opened. Such a case can cause larger-scale drainage than that from the opening of a branch englacial conduit. 3) Several lakes discharged twice in the same year, each time through a different conduit, indicating that the main englacial conduit can be abandoned and reused. 4) In some lakes, the water level gradually increased with nearly the same increase rate just before drainage. Such an increase may be an indicator of imminent lake drainage.

scholarly journals Comparison of random forests and other statistical methods for the prediction of lake water level: a case study of the Poyang Lake in China

2016 ◽  
Vol 47 (S1) ◽  
pp. 69-83 ◽  
Author(s):  
Bing Li ◽  
Guishan Yang ◽  
Rongrong Wan ◽  
Xue Dai ◽  
Yanhui Zhang
Keyword(s):  
Water Level ◽  
Random Forests ◽  
Lake Water ◽  
Poyang Lake ◽  
Time Lag ◽  
Water Levels ◽  
Support Vector ◽  
Lake Water Level ◽  
Water Level Variations

Modeling of hydrological time series is essential for sustainable development and management of lake water resources. This study aims to develop an efficient model for forecasting lake water level variations, exemplified by the Poyang Lake (China) case study. A random forests (RF) model was first applied and compared with artificial neural networks, support vector regression, and a linear model. Three scenarios were adopted to investigate the effect of time lag and previous water levels as model inputs for real-time forecasting. Variable importance was then analyzed to evaluate the influence of each predictor for water level variations. Results indicated that the RF model exhibits the best performance for daily forecasting in terms of root mean square error (RMSE) and coefficient of determination (R2). Moreover, the highest accuracy was achieved using discharge series at 4-day-ahead and the average water level over the previous week as model inputs, with an average RMSE of 0.25 m for five stations within the lake. In addition, the previous water level was the most efficient predictor for water level forecasting, followed by discharge from the Yangtze River. Based on the performance of the soft computing methods, RF can be calibrated to provide information or simulation scenarios for water management and decision-making.

scholarly journals Borehole water-level variations and implications for the subglacial hydraulics of South Cascade Glacier, Washington State, U.S.A.

1994 ◽  
Vol 40 (135) ◽  
pp. 293-304 ◽  
Author(s):  
Andrew G. Fountain
Keyword(s):  
Hydraulic Conductivity ◽  
Water Level ◽  
Water Flow ◽  
Washington State ◽  
Diurnal Variations ◽  
Water Levels ◽  
Seasonal Evolution ◽  
Borehole Water ◽  
Water Level Variations

AbstractBoreholes were drilled in South Cascade Glacier to investigate the hydraulics of subglacial water flow. Results indicate that subglacial water pressures are generally close to local ice-overburden pressures and that a subglacial debris layer probably exists. Calculations indicate that the range of hydraulic conductivity of this layer is 10−7-10−4m−1. The borehole water levels generally increased during the ablation season and may be caused by a seasonal evolution in the permeability of the debris layer. Water in the debris layer drains to a subglacial conduit, the existence of which is inferred by large diurnal variations in the water level of one borehole. These levels commonly reached the bottom of the glacier, indicating near-atmospheric pressures in the conduit.

scholarly journals Simultaneous drainage events from supraglacial lakes on the southern Inylchek Glacier, Central Asia

2021 ◽  
pp. 1-12
Author(s):  
Naoki Sakurai ◽  
Chiyuki Narama ◽  
Mirlan Daiyrov ◽  
Muhammed Esenamanov ◽  
Zarylbek Usekov ◽  
...  
Keyword(s):  
Water Level ◽  
Drainage Water ◽  
Water Levels ◽  
Aerial Images ◽  
Supraglacial Lakes ◽  
Surface Models ◽  
Increase Rate ◽  
Aerial Vehicle ◽  
Water Level Variations ◽  
Gradient Line

Abstract To understand the mechanism of simultaneous drainage event related to supraglacial lakes on a debris-covered glacier, we investigated water-level variations of supraglacial lakes on the southern Inylchek Glacier in Kyrgyzstan. To examine these variations, we used daily aerial images for 2017–2019 from an uncrewed aerial vehicle that were converted to 15 cm-digital surface models and ortho-images. Our main results are as follows: (1) When one lake drained, the water levels of other lakes simultaneously increased, indicating that drainage water is shared with several lakes through a main englacial conduit. In one drainage event, a branched off englacial conduit clearly connected to a main englacial conduit. (2) Sometimes several lakes discharged simultaneously, indicating that several lakes had connected to a main englacial conduit that had opened. Such cases can cause larger-scale drainage than that from the opening of a branched off englacial conduit. (3) Simultaneous drainage occurred twice in the same year, each time through a different conduit, indicating that the main englacial conduit can be abandoned and reused. (4) In some lakes, the water level on the hydraulic gradient line increased gradually with nearly the same increase rate just before drainage. Such an increase may be an indicator of a possible simultaneous drainage event.

scholarly journals The Influence of Hydrometeorological Conditions on Changes in Littoral and Riparian Vegetation of a Meromictic Lake in the Last Half-Century

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2651 ◽  
Author(s):  
Bogumił Nowak ◽  
Agnieszka E. Lawniczak-Malińska
Keyword(s):  
Water Level ◽  
Riparian Vegetation ◽  
Field Studies ◽  
Meteorological Conditions ◽  
Water Levels ◽  
Meromictic Lake ◽  
Low Flow ◽  
Coastal Zones ◽  
Half Century ◽  
Hydrometeorological Conditions

Changes in water levels in lakes play an important role in the development of their coastal zones and water trophy. The aim of this study was to assess the role of changes in hydrometeorological conditions in the development of littoral and riparian vegetation of a meromictic lake during the last half-century. The study was carried out in Lake Powidzkie, one of the largest water reservoirs located in central Poland. Water level and meteorological conditions were analyzed in the period 1961–2015. Modifications in the range of plant communities were analyzed on the basis of cartographic materials and field studies. Meteorological conditions, especially precipitation and evaporation, were found to strongly affect the lake's water retention, whilst they had less of an effect on water levels. A significant effect of the lowering of the water level in Lake Powidzkie on the development of the littoral zone, whose area more than doubled over the last half-century, from 41.5 to 118.8 ha, was noted. The most dynamic development of the littoral was observed in the last quarter of the century, in which three of several years of low-flow were recorded. The occurrence of periods with an increased amount of precipitation, after dry periods, did not contribute to the reduction of the size of the rush zone and limitation of the development of woody vegetation.

scholarly journals EFFECTS OF WATER LEVEL VARIATIONS ON THE STABILITY OF ROCK ARMOURED SLOPES

2018 ◽  
pp. 44 ◽  
Author(s):  
Marcel R.A. Van Gent ◽  
Suzanna A.A. Zwanenburg ◽  
Jan Kramer
Keyword(s):  
Water Level ◽  
Physical Model ◽  
Model Tests ◽  
Water Levels ◽  
Level Variation ◽  
Water Level Variation ◽  
Stepwise Approach ◽  
Physical Model Tests ◽  
Water Level Variations ◽  
The Stability

Physical model tests on the stability of rock armoured slopes have been performed to demonstrate the importance of water level variations during a storm, due to a tide or a storm surge. For the stability of rock armoured slopes also the importance of the sequence of storms at various water levels has been studied. The test results indicate that a smooth sinusoidal water level variation leads to an increase in damage compared to the same wave conditions at a constant water level. Furthermore, a stepwise approach of the sinusoidal water level elevation leads to other results than the approach with a continuous water level variation, whereas the continuous water level variation resembles the peak of a storm or the tidal water level variation better than a stepwise approach. If storms with different water levels attack the armour layer, the damage is generally smaller than if all storms attack the armour layer at the same water level. Furthermore, the results have been discussed based on earlier analyses where the statistics of rock armoured slopes have been addressed and the importance of the length effect has been illustrated using a method to apply results from physical model tests to real structures.

scholarly journals Groundwater–surface water relations in regulated lowland catchments; hydrological and hydrochemical effects of a major change in surface water level management

2018 ◽  
Author(s):  
Joachim Rozemeijer ◽  
Janneke Klein ◽  
Dimmie Hendriks ◽  
Wiebe Borren ◽  
Maarten Ouboter ◽  
...  
Keyword(s):  
Land Use ◽  
Surface Water ◽  
Water Level ◽  
Water Exchange ◽  
Overland Flow ◽  
Water Levels ◽  
Pumping Stations ◽  
Level Regime ◽  
Solute Fluxes ◽  
Water Level Management

Abstract. In lowland deltas with intensive land use such as The Netherlands, surface water levels are tightly controlled by inlet of diverted river water during dry periods and discharge via large-scale pumping stations during wet periods. The conventional water level regime in these polder catchments is either a fixed water level year-round or an unnatural regime with a lower winter level and a higher summer level in order to optimize hydrological conditions for agricultural land use. The objective of this study was to assess the hydrological and hydrochemical effects of changing the water level management from a conventional fixed water level regime to a flexible, more natural regime with low levels in summer and high levels in winter between predefined minimum and maximum levels. Ten study catchments were hydrologically isolated and equipped with controlled inlet and outlet weirs or pumping stations. The water level management was converted into a flexible regime. We used water and solute balance modeling for catchment-scale assessments of changes in water and solute fluxes. Our model results show relevant changes in the water exchange fluxes between the polder catchment and the regional water system and between the groundwater, surface water, and field surface storage domains within the catchment. Compared to the reference water level regime, the flexible water level regime water balance scenario showed increased surface water residence times, reduced inlet and outlet fluxes, reduced groundwater-surface water exchange, and in some catchments increased overland flow. The solute balance results show a general reduction of chloride concentrations and a general increase in N-tot concentrations. The total phosphorus (P-tot) and sulfate (SO4) concentration responses varied and depended on catchment-specific characteristics. For our study catchments, our analyses provided a quantification of the water flux changes after converting towards flexible water level management. Regarding the water quality effects, this study identified the risks of increased overland flow in former agricultural fields with nutrient enriched top soils and of increased seepage of deep groundwater which can deliver extra nutrients to surface water. At a global scale, catchments in low-lying and subsiding deltas are increasingly being managed in a similar way as the Dutch polders. Applying our water and solute balance approach to these areas may prevent unexpected consequences of the implemented water level regimes.

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