Evolution Of Water Levels Research Articles

Short-duration prediction of urban storm-water levels using the residual-error ensemble correction technique

ABSTRACT Predicting water levels in urban storm-water sewer systems is a critical study that could provide vital information to help reduce the risk of flooding. This study proposed a new ensemble model based on the integration of a meta-learner model, residual-error corrections, and a multiple-output framework. To achieve the meta-learner model, three multiple-output data-driven-based (MOD) sewer flooding models employing support vector regression (SVR), k-nearest neighbor regression (KNR), and categorical gradient boosting regression (CGBR) techniques were constructed and applied to predict the short-duration evolution of water levels at seven storm-water gauging sites in Taipei city, Taiwan, considering 10-min datasets spanning nearly 6 years (2016–2021). The Bayesian optimization algorithm was utilized in the training phases for all the models to avoid overfitting or underfitting. Enhancing the analysis of feature importance was also conducted to explore model interpretability based on the SHapley Additive exPlanation (SHAP) algorithm. The outputs of storm-water management model (SWMM) were used as benchmark solutions. For the model validation phase, the proposed integrated model improved the lead-time-averaged Nash–Sutcliffe efficiency of single KNR, SVR, and CGBR models by 174.5, 42.4, and 69.4%, respectively, showing that the proposed accurate model could be useful for urban flood warning systems.

Advanced monitoring and numerical modelling of the stability, safety and reliability indicators of the earthen dam of Songloulou (Cameroon).

For the determination of global stability after long term advanced monitoring, artificial intelligence have been used for the data analysis of water level and displacements of Songloulou earth dam at Cameroon. Measurements of safety and reliability indicators follow changes set by piezometric and pendulums measurements. The results obtained from the artificial intelligence on the base of many years recording data have confirmed the relevance and robustness of this model. The ANFIS model combining the concept of neural network and fuzzy logic was used to simulate the behaviour of piezometers and pendulums in the dam. This model has provided satisfactory results, given in the large amount of data to be processed. The water level evolution is modelled using the ANFIS function integrated in the MATLAB software and the result is compared to that obtained by the HST method. Afterwards, the state of stress on the structure and stability of the slope at shear have been assessed based on the hydro mechanical behaviour using the GEOSTUDIO Finite Element computation software. The input parameters are: the head of water recorded in the piezometers and geotechnical parameters of the dam. The modelling results in terms of displacement are accurately consistent with the displacement measurements. The horizontal displacement of pendulums obtained by GEOSTUDIO is 80 mm and those measured directly of the pendulums have 70 mm of average value. The safety factor for slope stability according to 530 m water level is 1.5.

Different hydrological controls causing variable rates of Holocene peat growth in a lowland valley system, north-eastern Netherlands; implications for valley peatland restoration

The Drentsche Aa valley system in the glacial sandy landscape of the north-eastern Netherlands, is one of the many regional drainage systems in the north-western to central European Lowlands. Following deep incision in the Weichselian, ca 7 m of eutrophic peat has accumulated in the lower to middle reaches of the valley system in the Holocene, completely filling the Weichselian incision. We reconstructed the rate of water-level rise controlling peat growth at three locations in the valley system (representing the upper, middle and lower reaches), using 14C peat dates from compaction-free sampling sites on the sloping valley margin where the peat directly overlies the sandy Pleistocene subsurface. The 14C dates enabled the construction of curves showing the water-level evolution at each location. Our results show variable rates of Holocene peat growth in the valley system in response to different drivers of hydrological change: a strong increase in annual precipitation (onset Holocene), a decrease in evapotranspiration (10,000–8000 cal. years BP) and relative sea-level rise (after ~4500 cal. years BP). Because the identified hydrological controls on peat growth are regional, they probably ruled Holocene peat growth in many peat-filled valley systems in the north-western to central European Lowlands. Currently, there is growing attention for these valley systems in the context of European nature restoration efforts and climate change adaptation and mitigation measures. The present study underscores that large-scale hydrological measures outside the valley system are needed for restoration of degraded valley peatlands.

Assessing climate change impacts on hydrology: application to Zacapu and Pastor Ortiz aquifers (Mexico)

Abstract The agricultural and urban water requirements in the Angulo River basin (Mexico) along with land-use change and deforestation have caused great pressure on the region's groundwater availability. The potential climate change impact on groundwater levels of the Zacapu and Pastor Ortiz aquifers is evaluated in this study, using the climate model CMIP5, the hydrological module EVALHID, and the groundwater module AQUIVAL. The regional outputs from three Representative Concentration Pathway (RCP) climate scenarios (RCP 4.5, 6.0, and 8.5), for near future (2015–2039) and distant future (2075–2099) projections, indicate that the average annual temperature is expected to increase while a decrease in precipitation is projected over the basin. The assessment of infiltration and water level evolution in these groundwater systems indicates an infiltration reduction between 1.5 and 23%, producing a static level drop between 20 and 30 m in both aquifers.

Predicting Water Availability in Water Bodies under the Influence of Precipitation and Water Management Actions Using VAR/VECM/LSTM

Recently, awareness about the significance of water management has risen as population growth and global warming increase, and economic activities and land use continue to stress our water resources. In addition, global water sustenance efforts are crippled by capital-intensive water treatments and water reclamation projects. In this paper, a study of water bodies to predict the amount of water in each water body using identifiable unique features and to assess the behavior of these features on others in the event of shock was undertaken. A comparative study, using a parametric model, was conducted among Vector Autoregression (VAR), the Vector Error Correction Model (VECM), and the Long Short-Term Memory (LSTM) model for determining the change in water level and water flow of water bodies. Besides, orthogonalized impulse responses (OIR) and forecast error variance decompositions (FEVD) explaining the evolution of water levels and flow rates, the study shows the significance of VAR/VECM models over LSTM. It was found that on some water bodies, the VAR model gave reliable results. In contrast, water bodies such as water springs gave mixed results of VAR/VECM.

Channel response to low water levels in the Pearl River Delta: A multi-decadal analysis

The Pearl River Delta is a composite delta with one of the densest channel networks in the world. To analyze the internal erosion/deposition characteristics of the net channel area, this paper studies the upstream evolution characteristics using Digital Elevation Model data from local channel sections. We attempt to establish the relationship between the changes in low water level and erosion rate by using the accumulated data for the main stream and hydrological stations over the past 50 years, including the distributions of flow and sediment at the top of the net channel area and the erosion/deposition data of a typical channel section. In fact, the net channel area has been in a forced-erosion state (Artificial sand excavation) for a long time, forcing the flow and sediment distributions at Makou and Sanshui stations to adjust from 1993 to the present. Although the incoming sedimentation is far less than the net erosion, and there are similarities and differences in the sources of the incoming flow and sediment from the main stream, the internal characteristics of the upper and lower reaches of the delta have not changed substantially; they have always been stable, slow deposition channels. The forced undercutting is concentrated within width-depth ratios of approximately 50–250, which still meets the evolution characteristics of the natural channel. Artificial sand excavation during the 1980s tended to enhance the characteristics. However, the sudden increase in the undercutting rate has forced chaotic changes in the low water level since 1990, and the sediment transport rate decreased sharply. The phenomena of salt tides retrogression and retrogressive erosion generally happen, the water level evolution in the net channel area is chaotic, and continuous undercutting is still occurring.

Modelling the water balance of Lake Victoria (East Africa) – Part 2: Future projections

Abstract. Lake Victoria, the second largest freshwater lake in the world, is one of the major sources of the Nile river. The outlet to the Nile is controlled by two hydropower dams of which the allowed discharge is dictated by the Agreed Curve, an equation relating outflow to lake level. Some regional climate models project a decrease in precipitation and an increase in evaporation over Lake Victoria, with potential important implications for its water balance and resulting level. Yet, little is known about the potential consequences of climate change for the water balance of Lake Victoria. In this second part of a two-paper series, we feed a new water balance model for Lake Victoria presented in the first part with climate simulations available through the COordinated Regional Climate Downscaling Experiment (CORDEX) Africa framework. Our results reveal that most regional climate models are not capable of giving a realistic representation of the water balance of Lake Victoria and therefore require bias correction. For two emission scenarios (RCPs 4.5 and 8.5), the decrease in precipitation over the lake and an increase in evaporation are compensated by an increase in basin precipitation leading to more inflow. The future lake level projections show that the dam management scenario and not the emission scenario is the main controlling factor of the future water level evolution. Moreover, inter-model uncertainties are larger than emission scenario uncertainties. The comparison of four idealized future management scenarios pursuing certain policy objectives (electricity generation, navigation reliability and environmental conservation) uncovers that the only sustainable management scenario is mimicking natural lake level fluctuations by regulating outflow according to the Agreed Curve. The associated outflow encompasses, however, ranges from 14 m3 day−1 (−85 %) to 200 m3 day−1 (+100 %) within this ensemble, highlighting that future hydropower generation and downstream water availability may strongly change in the next decades even if dam management adheres to he Agreed Curve. Our results overall underline that managing the dam according to the Agreed Curve is a key prerequisite for sustainable future lake levels, but that under this management scenario, climate change might potentially induce profound changes in lake level and outflow volume.

Time-lapse photography for monitoring reservoir leakages (Montejaque dam, Andalusia, southern Spain)

AbstractA methodology based on the use of time-lapse photographs is presented to evaluate the leakages over time of a reservoir (Montejaque dam, Málaga Province, Spain) that feeds a karstic aquifer. In particular, photographic control allows the evolution of water levels in the dam and the river that feeds it to be monitored. Through changes in water volume, which are calculated from the level differences, daily leakages are evaluated, and the relationship between leakages and the water level of the reservoir is established. The proposed method includes adjusting the hydric balance and the use of digital terrain model and climate data. The inputs (river flow and direct precipitation) and other outputs (direct evaporation) are also evaluated. Values between 4 m3/s and 0.35 m3/s are obtained for the reservoir infiltration, clearly superior to the values obtained at the time of the construction of the dam in the 1920s. Mobilisation of the filling of fractures and conduits in karstic massif and calcite dissolution are processes that can influence this behaviour. When the water level is very low, the obtained values are below the historical leakages due to deposition of clay sediments at the reservoir bottom.

New experimental dataset for partial dam-break floods over mobile beds

ABSTRACTAn experimental investigation is presented on partial dam-break floods over mobile beds, with different bed sediment compositions and initial upstream and downstream water levels. Detailed measurements were carried out, including water level evolution, final bed topography and bed surface sediment composition. Intense scour occurred immediately downstream from the dam, followed by significant deposition and small bed forms which were only observed in cases with non-uniform sediment. Also, final bed sediment surface showed a general coarsening trend in the intense scour and deposition areas and a coarse-fine-coarse structure in the remaining reach with small bed forms. The effects of the bed sediment composition and of the difference between initial upstream and downstream water levels on bed deformation are evaluated. This work facilitates new understanding of dam-break floods over mobile beds especially with non-uniform sediment, and provides a new experimental dataset which can be exploited to underpin the development of mathematical models.

Mapping groundwater level and aquifer storage variations from InSAR measurements in the Madrid aquifer, Central Spain

Groundwater resources are under stress in many regions of the world and the future water supply for many populations, particularly in the driest places on Earth, is threatened. Future climatic conditions and population growth are expected to intensify the problem. Understanding the factors that control groundwater storage variation is crucial to mitigate its adverse consequences. In this work, we apply satellite-based measurements of ground deformation over the Tertiary detritic aquifer of Madrid (TDAM), Central Spain, to infer the spatio-temporal evolution of water levels and estimate groundwater storage variations. Specifically, we use Persistent Scatterer Interferometry (PSI) data during the period 1992–2010 and piezometric time series on 19 well sites covering the period 1997–2010 to build groundwater level maps and quantify groundwater storage variations. Our results reveal that groundwater storage loss occurred in two different periods, 1992–1999 and 2005–2010 and was mainly concentrated in a region of ∼200km2. The presence of more compressible materials in that region combined with a long continuous water extraction can explain this volumetric deficit. This study illustrates how the combination of PSI and piezometric data can be used to detect small aquifers affected by groundwater storage loss helping to improve their sustainable management.

Hydrological regime and modeling of three ponds of the Mediterranean area (south of Córdoba, Spain)

In this investigation, hydrological time series of three ponds located in the province of Cordoba (southern Spain) at a daily scale has been analyzed. For the first time, a detailed evolution of the water level of Jarales, Conde, and Amarga ponds has been acquired by means of the installation of level loggers in the deepest point of each of the ponds. We have modeled the water level evolution using a simple one-dimensional model. Calibration of the model was very satisfactory in two of the ponds. The model was then setup and simulated for two future Scenarios: A (IPCC climate change scenario) and B (climate change + groundwater withdrawal within the basin). Two ponds were classified as discharge ponds, which are the hydrological regime of the majority of southern Spain’s continental ponds. One was classified as a recharge pond. With regard to the results obtained in the simulations for Scenarios A and B, our results showed that IPCC scenario will reduce hydroperiod significantly in the three ponds, with a reduction of approximately 500 cm in the water level. With respect to groundwater withdrawal within the basins, results show a very high impact in the hydroperiod in Amarga and Conde ponds.

Analysis of Wetland Ecosystem Response of Poyang Lake with Water Level Evolution Base on TM Images

The response of wetland ecosystem of Poyang Lake influenced by hydrological process changes was addressed. The spatial distribution and area of water, water-land transition zone and exposed grass continent were obtained by classification and extraction of wetland based on Landsat-TM images and analysis of observed hydrologic data. The results indicated that wetland ecological system of Poyang Lake was characteristic of complexity,sensitivity,mutability and fragility, and the optimum water level of wetland in Poyang Lake was 10-14m.

Investigation of Dam-Break Flow Over Abruptly Contracting Channel With Trapezoidal-Shaped Lateral Obstacles

The present paper aims to investigate the dam-break flow over dry channel with an abrupt contracting part in certain downstream section. A new experiment was carried out in a smooth-prismatic channel with rectangular cross section and horizontal bed. A digital imaging technique was adopted for flow measurement and thus flood wave propagation was sensitively obtained. Synchronous filmed images of the dam-break flow were nonintrusively acquired with three cameras, through glass sidewalls of the channel. Free surface profiles and time evolution of water levels were derived directly from the recorded video images using virtual wave probe without disturbing the flow. Furthermore, the present study highlights the formation and propagation of the negative bore due to abruptly contracting channel. The measured results were compared with the numerical solution of Reynolds averaged Navier–Stokes (RANS) equations with k-ε turbulence model and good agreement was achieved. New experimental data can be useful for scientific community to validate numerical models.

Dam-break flows over mobile beds: experiments and benchmark tests for numerical models

In this paper, the results of a benchmark test launched within the framework of the NSF–PIRE project “Modelling of Flood Hazards and Geomorphic Impacts of Levee Breach and Dam Failure” are presented. Experiments of two-dimensional dam-break flows over a sand bed were conducted at Université catholique de Louvain, Belgium. The water level evolution at eight gauging points was measured as well as the final bed topography. Intense scour occurred close to the failed dam, while significant deposition was observed further downstream. From these experiments, a benchmark was proposed to the scientific community, consisting of blind test simulations, that is, without any prior knowledge of the measurements. Twelve different teams of modellers from eight countries participated in the study. Here, the numerical models used in this test are briefly presented. The results are commented upon, in view of evaluating the modelling capabilities and identifying the challenges that may open pathways for further research.

Changes in water level, land use, and hydrological budget in a semi-permanent playa lake, Southwest Spain

Medina playa lake, a Ramsar site in western Andalusia, is a brackish lowland lake of 120 ha with an average depth of 1 m. Water flows into Medina from its 1,748-ha watershed, but the hydrology of the lake has not previously been studied. This paper describes the application of a water budget model on a monthly scale over a 6-year period, based on a conceptual hydrological model, and considers different future scenarios after calibration to improve the understanding of the lake's hydrological functioning. Climatic variables from a nearby weather station and observational data (water-level evolution) were used to develop the model. Comparison of measured and predicted values demonstrated that each model component provided a reasonable output with a realistic interaction among the components. The model was then used to explore the potential consequences of land-use changes. Irrigation of olive groves would significantly reduce both the hydroperiod (becoming dry 15% of the time) and the average depth of the lake (water level <0.5 m 40% of the time). On the other hand, removal of an artificial overflow would double the average flooded surface area during high-water periods. The simulated water balance demonstrates that the catchment outputs are dominated by lake evaporation and surface outflow from the lake system to a creek. Discrepancies between predicted and observed water levels identify key areas of uncertainty for future empirical research. The study provides an improved basis for future hydrological management of the catchment and demonstrates the wider utility of this methodology in simulating this kind of system. This methodology provides a realistic appraisal of potential land-use management practices on a catchment-wide scale and allows predictions of the consequences of climate change.

Research on the model of Nam Co lake water level evolution based on GIS

Abstract The earth is warming in recent decade, most glaciers in western China have retreated. The Qinghai-Tibet Plateau is a closed lake basin, so glacier changes will directly affect the water balance and hydrological cycle of basin. According to principles of river basin water balance, considering the lakes, glaciers, streams of basin as a whole, based on Baingoin, Nakqu, Xainza, Damxung four weather stations data in nearly a decade of date, we build the Nam Co basin water balance model aiming with GIS technology to simulate changes of Nam Co Lake in recent years, and the results uses the expression of three-dimensional dynamic image to show the evolution of the Nam Co lake water level.

Experimental study of dam-break flow against an isolated obstacle

During a dam-break flow, the whole valley is involved, which implies that roads, bridges and urban buildings become obstacles to the flow. The purpose of this paper is to provide data about the influence of such an obstacle on a dam-break wave, the obstacle being an idealised representation of a single building. The experimental set-up consists in a channel with a rectangular shaped obstacle, representing a building, placed immediately downstream from the dam. The building is neither centred in the channel, nor aligned with the flow direction. Flow observation shows that after the violent impact of the wave on the building, the flow is forced to change its direction to pass the building. This implies the formation of hydraulic jumps with the consequence that the water level may rise locally higher than without building. Behind the building, a wake zone is observed. Then, further downstream, the flow slowly recovers the structure it would have had without the building. Several measurement devices were used to characterise the flow. At five different locations, the water level evolution was measured by means of water level gauges while the velocity was measured by means of an acoustic Doppler velocimeter. Then, the surface velocity field was obtained using digital imaging techniques.

A groundwater-based, objective-heuristic parameter optimisation method for a precipitation-runoff model and its application to a semi-arid basin

A hydrologic model calibration methodology that is based on groundwater data is developed and implemented using the US Geological Survey's precipitation-runoff modelling system (PRMS) and the modular modelling system (MMS), which performs automatic calibration of parameters. The developed methodology was tested in the Akrotiri basin, Cyprus. The necessity for the groundwater-based model calibration, rather than a typical runoff-based one, arose from the very intermittent character of the runoff in the Akrotiri basin, a case often met in semi-arid regions. Introducing a datum and converting groundwater storage to head made the observable groundwater level the calibration indicator. The modelling of the Akrotiri basin leads us to conclude that groundwater level is a useful indicator for hydrological model calibration that can be potentially used in other similar situations in the absence of river flow measurements. However, the option of an automatic calibration of the complex hydrologic model PRMS by MMS did not ensure a good outcome. On the other hand, automatic optimisation, combined with heuristic expert intervention, enabled achievement of good calibration and constitutes a valuable means for saving effort and improving modelling performance. To this end, results must be scrutinised, melding the viewpoint of physical sense with mathematical efficiency criteria. Thus optimised, PRMS achieved a low simulation error, good reproduction of the historic trend of the aquifer water level evolution and reasonable physical behaviour (good hydrologic balance, Reasonable match of aquifer level evolution, good estimation of mean natural recharge rate).

Artificial neural network approach to flood forecasting in the River Arno

The basin of the River Arno is a flood-prone area where flooding events have caused damage valued at more than 100 billion euro in the last 40 years. At present, the occurrence of an event similar to the 1966 flood of Firenze (Florence) would result in damage costing over 15.5 billion euro. Therefore, the use of flood forecasting and early warning systems is mandatory to reduce the economic losses and the risk for people. In this work, a flood forecasting model is presented that exploits the real-time information available for the basin (rainfall data, hydrometric data and information on dam operation) to predict the water-level evolution. The model is based on artificial neural networks, which were successfully used in previous works to predict floods in an unregulated basin and to predict water-level evolution in the Arno basin under low flow conditions. Accurate predictions are obtained using a two-year data set and a special treatment of input data; which allows a balance to be found between the spatial and temporal resolution of rainfall information and the model complexity. The prediction of water-level evolution remains accurate within a forecast time ahead of 6 h, which is the minimum time lag for the river to respond to dam releases under saturated conditions of the basin. The predicted flow rate percentage error ranges from 7 to 15% from the 1-h ahead to 6-h ahead predictions, and the accuracy of prediction increases for each time ahead of prediction, as the flow rate increases, suggesting that the model is particularly suited for flood forecasting purposes.

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