Water Level Changes Research Articles

Monitoring spatiotemporal changes of urban surface water based on satellite imagery and Google Earth Engine platform in Dhaka City from 1990 to 2021

BackgroundThis study focuses on Dhaka City and its impact on urban surface water. Cities, ecosystems, and agriculture need surface water. It is crucial for water resource planning and environmental preservation. The primary aim is to study how urbanization has affected surface water in Dhaka City over 30 years using satellite imagery.MethodsThe study analyzed three decades of urban surface water shifts using Landsat 5 TM and Landsat 8 OLI/TIRS satellite imagery and Google Earth Engine (GEE) with JavaScript code for water ratio index detection. To investigate water level changes, field observation surveys and secondary data analysis were conducted. This integrated methodology simplified surface water data extraction and analysis, making remote sensing easier and allowing cloud-based satellite data processing.ResultsThe study demonstrates that the amount of surface water in cities is going down, from 36.23 km2 in 1990 to 5.83 km2 in 2021, which is an enormous decrease. This means that about 20 square kilometers, or 45 percent of the water's surface, have been lost in the last 30 years. The main reasons for the drop are unplanned expansion of cities, accelerated real estate development, and more trade and economic activities in the study area.ConclusionsThe GEE algorithms provide useful insights into surface water's maximum and minimum extent, enabling appropriate planning and management. These findings aid Dhaka City's water resource management and environmental protection.

Prediction of Storm Surge Water Level Based on Machine Learning Methods

Storm surge disasters result in severe casualties and economic losses. Accurate prediction of storm surge water level is crucial for disaster assessment, early warning, and effective disaster management. Machine learning methods are relatively more efficient and straightforward compared to numerical simulation approaches. However, most of the current research on storm surge water level prediction based on machine learning methods is primarily focused on point predictions. In this study, we explore the feasibility of spatial water level prediction using the ConvLSTM model. We focus on the coastal area of Guangdong Province and employ MIKE21(2019) software to simulate historical typhoons that have made landfall in the region from 1991 to 2018. We construct two datasets: one for direct water level prediction and the other for indirect water level prediction based on water level changes. Utilizing the ConvLSTM network, we employ it to forecast storm surges on both datasets, effectively capturing both temporal and spatial characteristics and thus ensuring the production of dependable results. When directly predicting water levels, we achieve an MAE (mean absolute error) of 0.026 m and an MSE (mean squared error) of 0.0038 m2. In contrast, the indirect prediction approach yields even more promising results, with an MAE of 0.014 m and an MSE of 0.0007 m2. Compared to traditional numerical simulation methods, the ConvLSTM-based approach is simpler, faster, and able to predict water levels accurately without boundary conditions or topographies. Furthermore, we consider worst-case scenarios by predicting the maximum water increase value using the random forest model. Our results indicate that the random forest model can serve as a valuable reference for forecasting the maximum water increase value of typhoon storm surges, supporting effective emergency responses to disasters.

Ecological and photosynthetic characteristics of Carex schmidtii with respect to hydrological fluctuations

Hydrological fluctuations are key abiotic stresses that influence plant growth and photosynthetic processes of wetland plants. However, the response mechanism of the plant characteristics and photosynthesis of Carex schmidtii, with respect to hydrological fluctuations, are still unclear. Comparative studies of plant size parameters, biomass parameters, and photosynthesis parameters of C. schmidtii under the interactive influence of initial water depth (WD), water-level amplitude (WA), and duration time, were performed. The coupling relationship between any two factors of the plant characteristics of C. schmidtii was also examined. Generally, the results showed that the WD and WA treatments, and the duration time, significantly affected plant size, biomass, and photosynthesis of C. schmidtii. The exception was the effect by the WA on the biomass and the NPQ. Furthermore, the biomass and photosynthesis of C. schmidtii were significantly affected by the interactive effects by WD and WA. The plant size, biomass, and photosynthesis parameters of C. schmidtii first increased and then decreased over time. Larger values of plant size, biomass, and photosynthesis parameters (except for qL and NPQ) were found for the treatment with an initial water depth of 0 cm. As was the situation with WD, the largest values of plant height, chlorophyll content, Fv/Fm, and ΔFv/Fm’ were obtained for a water-level amplitude of 0 cm. Furthermore, the chlorophyll content was positively related to the plant size parameters, Fv/Fm, ΔFv/Fm’, and qL. Except for qL, ΔFv/Fm’ had a significant relationship with all plant factors. Lower water levels and smaller water level changes are more conducive to the growth and photosynthese of C. schmidtii. Plant size, biomass accumulation and photosynthesis of C. schmidtii collectively coped with hydrological fluctuations. The findings have improved understanding of the response of C. schmidtii to hydrological fluctuations. They have thereby provided invaluable information for the restoration, management and conservation of tussock wetlands.

Hydrodynamic response to bathymetric changes in Tampa Bay, Florida

Bathymetric changes within estuarine and coastal waters can alter the hydrodynamic evolution of sea level and currents, which in turn can influence the ecosystem by altering material property distributions. Here we apply the Tampa Bay Coastal Ocean Model (TBCOM), with an unstructured, high-resolution grid to investigate the hydrodynamic response to bathymetric changes at the periphery of the Tampa Bay mouth over a relatively small area when compared to the whole model domain. Two separate numerical experiments are conducted with the same forcing, one using the original bathymetry and the other employing a revised synthetic bathymetry. The simulated sea level, amplitude and phase of the M2 tide, and associated currents are compared for the two experiments. Significant changes in water level (up to+/-10 cm) and current velocities (up to 20 cm/s) are found in the shallow peripheral area with the two different bathymetric data sets. These bathymetric influences are not limited to the locations where the bathymetric changes occur; they also extend to remote areas of the bay. Since Tampa Bay bathymetry varies with storm-induced sediment redistributions and human actives such as shipping channel dredging and beach nourishment, these findings emphasize the need for accurate and updated bathymetry for coastal ocean modeling and applications.

Origin and post‐glacial evolution of surface cracks: A case study from the area of the Last Glaciation, north‐eastern Poland

AbstractThe analysis of LiDAR‐based digital elevation models revealed the existence of groups of longitudinal fractures in the ground in northern Poland at the limit of the ice sheet's extent during its last maximum. Our research on the closed elongated depressions (CEDs) of the Jedwabno test field (Szuć site, north‐east Poland) focuses on explaining their origins and their post‐glacial history. This region was covered by an ice sheet and glacitectonically active during the Vistulian, and at least some surface fractures are possible witnesses to this activity. Using geomorphological mapping, sedimentological and geophysical research, we assumed it was related that the origin of these features here is associated with groundwater migration at the end of the Vistulian glaciation or later when groundwater flow intensified due to a rapid climate warming that caused permafrost to melt. The thawing of permafrost caused to transition from continuous permafrost to discontinuous, which in turn created groundwater flow that was probably responsible for the development of the surface cracks (fractures). Radiocarbon, palaeobiological (pollen, Cladocera) and geochemical studies allowed for an estimation of the formation time of these unique surface cracks in the Older Dryas. Prevailing conditions were also reconstructed for the later dynamic changes of the end of the Late Vistulian glaciation and in the Late Holocene until the Subatlantic Period (Megalayan stage). The surface cracks with steep slopes, despite their small area, are extraordinary sedimentation traps that have, in a special way, retained an almost complete record of the environmental and climate changes of the Late Glacial. There are sedimentological gaps in the Holocene, especially after the Preboreal (old part of the Greenlandian Stage), caused by changes in water levels, aeolian processes and human activity.

Satellite Derived Bathymetry and Water Level Change in Beysehir Lake

Abstract Several factors, including water level, depth, water quality, biodiversity, and tourist activities, play a crucial role in the sustainability of lakes, and therefore require constant monitoring. This study aimed to examine the water level changes of Lake Beysehir between 2015 and 2020 and determine whether there was a difference in bathymetry as the lake water level changed. To achieve this, lake water level data was first obtained from Copernicus Global Land Service, which uses satellite altimetry data to determine water level changes in Beysehir Lake. Sentinel-2 multispectral high-resolution satellite images obtained from Sentinel-Hub were then used to determine the depth of the lake. Finally, these high-resolution satellite images were processed using the open-source SNAP software developed by the European Space Agency. A decreasing trend of -9.8 ± 0.8 cm/yr in the lake water level between 2015 and 2020 was revealed by the analysis. The Empirical Satellite-Derived Bathymetry map was produced, and the maximum and average depth of the lake was determined after the required corrections were applied to the Sentinel-2 satellite images. The average depth, which was 8.44 meters in 2015, was found to have decreased to 4.06 meters in 2020. Additionally, a 0.92 correlation was found between the decrease in the lake water level and the average depth change.

Groundwater Level Analysis of Sathyamangalam Region, Tamil Nadu, India Using GIS

The Morphometric and groundwater analysis (water level and flow direction) of Sathyamangalam, having total area of 2.24 lakhs hectares was carried out using geographical information system (GIS). The Watershed characteristics such as slope, size, shape and Morphological Analysis such as linear aspects namely Stream order, Bifurcation ratio, Stream length, Length ratio and Areal aspects in particular Drainage density are analysed using ArcGIS software. And also, groundwater level for four years (2008, 2011, 2014 and 2017) and groundwater flow directions using Piezometric well data were also analyzed. In Watershed characteristics, the size of the study area is 2.24 Lakh ha and designated as sub- catchment watershed. The shape is circular i.e. Fan shape. The total length of contour line is about 11055.86 km and the average slope was 24.68% for 50m interval contour. In Morphological analysis, totally 6487 streams were observed and the total length of stream was 3758.2 km. The study location has bifurcation ratio ranging from 1.56 to 3.62 and length ratio of stream was calculated as 1.678 km/km2. In Piezometric analysis, the major water level changes occur in Northwest of Sathyamangalam. Here, the depth of water from the earth surface decreases from 12.67 m in the year of 2008 to 3.95 m in the year of 2017.

Determination of Replacement Material Thickness in the Case of Expansive Soil in Dams

One simple solution to reduce the impact of damage caused by swelling on expansive soil is to replace it with soil that has better properties. Unlike replacing expansive soil material in the subgrade or foundation layer, replacing expansive material in a constructed dam requires special consideration, as fluctuating reservoir water levels and rainfall cycles affect the active zone of expansive soil, which will affect the stability of the dam. Therefore, this study was conducted to determine the thickness of the replacement layer, which is also the active zone of expansive soil in the dam, by modeling the stability of the dam against changes in reservoir water levels and rainfall cycles with parent analysis using finite element and limit equilibrium method programs. One example of dam damage caused by expansive soil was used as a case study. The study results show that changes in the wet-dry active zone can be used as a basis for determining the thickness of the replacement material in cases of expansive soil in dams.

Geomorphic Response of a Coastal Berm to Storm Surge and the Importance of Sheet Flow Dynamics

AbstractDuring a storm, as the beach profile is impacted by increased wave forcing and rapidly changing water levels, sand berms may help mitigate erosion of the backshore. However, the mechanics of berm morphodynamics have not been fully described. In this study, 26 trials were conducted in a large wave flume to explore the response of a near‐prototype berm to scaled storm conditions. Sensors were used to quantify hydrodynamics, sheet flow dynamics, and berm evolution. Results indicate that berm overtopping and offshore sediment transport were key processes causing berm erosion. During the morphological evolution of the beach profile, two sand bars were formed offshore that attenuated subsequent wave energy. The landward extent of that energy was confined to the seaward foreshore, inhibiting inundation of the backshore. Net offshore‐directed transport was dominant when infragravity motions increased in the swash zone. Conversely, the influence of incident‐band motions on sediment transport was relatively greater in the inner‐surf zone. Near‐bed flow velocities and sheet flow layer thicknesses were larger in the swash zone than in the inner‐surf zone. This paper also provides a valuable analysis between morphology‐estimated total sediment transport rates and rates derived from in situ measurements. Sheet flow dynamics dominated foreshore cross‐shore sediment processes, constituting the largest portion of the total sediment transport load throughout the berm erosion.

Estimation of Coastal Area and Lake Water Level Changes Using High-Resolution Altimetry

Radar satellite altimeters are widely used in offshore areas, whereas they are underutilized in coastal areas due to a number of interference factors. Altimeter satellite data can be used to summarize elevation information at 1 Hz for offshore areas, but for areas close to land, it is more effective to utilize imagery with a resolution of 20 Hz to provide a more detailed representation. The use of highresolution satellite altimeter data is expected to increase the amount of data available for hydrological data such as complex coastlines and small lakes. Therefore, in this study, we investigated the applicability of 20 Hz altimeter data in the Korean Peninsula. First, the accuracy was analyzed by comparing the 20 Hz altimeter data from the Jason-3 satellite with the Ulleungdo tide data. Second, we compared the 20 Hz altimeter data from the Sentinel-3A satellite with the water level data of Soyang Lake to see if it can be applied to land areas. In the case of inland lakes, the water level is estimated to be affected by the discharge volume due to heavy rainfall in summer, and it was determined that the satellite altimeter data can be utilized. Therefore, utilizing the data from this study is expected to improve the accuracy of hydrological analysis in coastal and lake environments.

Climate change impact on the compound flood risk in a coastal city

Compound flooding caused by a combination of rainfall and water level may occur in coastal cities. Under the influence of climate change, compound flooding is likely to be intensified. In this paper, using the main urban area of Haikou City as an example, we developed an event-based statistical-numerical hybrid framework to investigate the effects of sea level rise (SLR) and future rainfall changes on compound flood risk. Future rainfall was predicted by using five global climate models (GCMs) in CMIP5. A combination of GCMs and IPCC AR5 was used to predict the future SLR. The copula was then used to calculate the probabilistic risk of compound flooding (OR joint probability and failure probability) for historical and future scenarios, and the numerical model was utilized to evaluate the risk of inundation under historical and future scenarios. The probabilistic risk results show that both the probability and the failure probability of compound flooding will increase in the future. Output from GCMs indicate that when the OR event of the 5-year event (the compound flooding when at least one of the 5-year rainfall and the 5-year water level happens) occurs, the joint probability of future compound flooding will likely increase to 37.5%. The numerical model results indicate that the flood extent, flood depth and flood duration will increase under the influence of future rainfall and SLR. Under the impact of climate change, the flood depth in the FS5 case will increase by 22.85% and the flood extent in the FS5 case will increase by 41.42% compared to HS5. By controlling for variables, we also find that the combined impact of future changes in rainfall and water level on the magnitude of flooding is greater than the sum of their individual impacts. Finally, we find that water storage facilities and tide gates could be set up to mitigate compound flooding under climate change.

Changing water levels and sandy barrier morphodynamics, eastern lake Ontario

Changing water levels and sandy barrier morphodynamics, eastern lake Ontario

Monitoring Lake Level Changes in Bosten Lake from 2003-2021 based on Multi-source Satellite Altimetry Data

The investigation of freshwater lake water resource changes in arid regions is crucial for understanding the evolution of regional lake dynamics under climate change, given their value and limited availability. This study aims to overcome the limitations of traditional water level monitoring methods and address the practical need for monitoring water level changes in Lake Bosten, located in the arid and semi-arid regions of China. To this end, we employed ICESat, ICESat-2, and CryoSat-2 altimetry data, as well as Landsat 8-OLI optical remote sensing data, to obtain the water level information for Bosten Lake from 2003 to 2022. We analyzed the temporal variation of the lake level and discussed the response of the lake level to climate and human activities in the context of temperature, precipitation data, and human water use. The water level of Lake Bosten exhibited a decreasing and then increasing trend, with three rising and three falling intervals, respectively. The intra-year variation of the lake water level exhibited bimodal characteristics, and the fluctuation range of water level during abundant water periods was greater than that during dry periods. Finally, we correlated the extracted lake water level with the measured water level at the hydrological station and found a significant positive linear correlation between the observed water level of Bosten Lake based on satellite altimetry and the measured water level at the hydrological station, with an overall correlation coefficient of 0.896 and 0.934 (P < 0.01), indicating high accuracy of the water level results obtained in this study. The dynamics of Lake Bosten are influenced by a combination of climate change, hydrological elements, and human activities, with a relatively weak relationship between climate change and lake volume and a strong influence of human activities. Multi-source altimetry satellites provide a powerful tool for monitoring lake water levels over a long time scale, which is critical for studying lake water level changes and their response to climate and the environment.

Synoptic results on the potential impacts of the Lake Maggiore water management strategy on freshwater littoral ecosystems and invertebrate biocoenosis (NW, Italy)

The first results of the application of the integrated multidisciplinary protocol to study the effects of water level management on the Lake Maggiore littoral habitats and biocoenosis are presented. The "Parchi Verbano Ticino" project (2019-2021, ID: 481668) was the driving force to fine-tune the monitoring and management system of multidisciplinary information (chemistry, hydro-morphology, macro- and meio-fauna monitoring). The study reveals that water level fluctuations in Lake Maggiore, sometimes characterized by measurable changes in water levels, have remarkable effects on littoral habitats and on the structure and function of macro- and meiofaunal assemblages living there. Overall, this study provides insights into the potential impacts of Lake Maggiore water management strategy on freshwater littoral ecosystems during late spring-early summer, and emphasizes the need for a comprehensive understanding of the lake ecosystem dynamics. Thanks to the results achieved, publicly endorsed water management rules will be stated, for the late spring-early summer period, considering frequency and amplitude of water level fluctuations as crucial factors in management plans to mitigate their impacts. The endorsed rules turn out to be a negotiated compromise between the maintenance of ecosystem services and the protection of littoral life below water.

Climate change variables modify microbial community structure and soil enzymes involved in nitrogen and phosphorus metabolism

Anthropogenic activities have threatened soil biodiversity which has a direct link with agricultural sustainability and ecosystem functionality. This study is aimed at investigating the changes in soil microbial biomass and enzyme activity in response to variations of primary climatic variables such as temperature and water regimes. Rhizosphere and non-rhizosphere soil samples were collected from an agricultural field of a rainfed area and transported to the laboratory for physicochemical analysis. These soil samples were preserved at 4 °C to be used for studying microbial biomass and enzymatic activities at varying soil temperatures (22, 33, and 44 °C) and water levels (30, 45, and 60% water holding capacity (WHC)). Urease and phosphatase activity showed a significant increase with increasing temperature. The urease and phosphatase values at a temperature of 44 °C after six weeks showed an increase of 19% and 67%, respectively, compared to the values before incubation. The microbial biomass carbon and the microbial biomass nitrogen decreased with increasing temperature and increasing time intervals. Under different temperatures, the diversity analyses of field samples showed maximum dominance of phylum proteobacteria with 70% relative abundance. With increasing water content, a relative decrease in the abundance of proteobacteria was observed. Water variability had non-significant effects on enzyme activity except at 30% WHC where a significant decrease (up to 14%) in urease activity was observed. The results showed a positive correlation between urease (r = 0.81) and phosphatase activity (r = 0.84) vs. an increase in temperature from 22 to 44 °C in soil. Based on these findings, it is concluded that changes in temperature and water levels modify microbial biomass, microbial community structure, and soil enzymatic activities involved in nitrogen and phosphorus metabolism.

Dam Surface Deformation Monitoring and Analysis Based on PS-InSAR Technology: A Case Study of Xiaolangdi Reservoir Dam in China

The Xiaolangdi Dam is a key project for the control and development of the Yellow River. It bears the functions of flood control, controlling water and sediment in the lower reaches, ice prevention, industrial and agricultural water supply, power generation, and so on. Its safety is related to people’s life and property safety and local economic and social development. It is of great significance to carry out comprehensive and regular deformation monitoring for dams since the deformation is an important evaluation index for dam safety. Interferometric Synthetic Aperture Radar (InSAR) technology has been a rapidly evolving technology in the field of space geodesy in recent years. It offers advantages such as high monitoring precision, extensive coverage, and high monitoring point density, making it a powerful tool for monitoring deformations in hydraulic engineering projects. Based on Sentinel-1 data covering the Xiaolangdi Dam from September 2020 to November 2022, the PS-InSAR technique was used to obtain the surface deformation of the Xiaolangdi Dam, and reservoir water level data on image acquisition dates were obtained for joint analysis. The results show that there is a large deformation in the center of the dam crest of the Xiaolangdi Dam, while both sides of the slope and downstream dam foot are relatively stable. The time series deformation of the dam body is closely related to the reservoir water level change. When the water level increases, the dam body tends to deform downstream; when the water level decreases, the dam body tends to deform upstream. The deformation and water level of the Xiaolangdi Dam exhibit a clear negative correlation. There is no significant cumulative deformation on the dam slopes or at the base of the dam. However, cumulative deformation occurs over time in the central area of the dam’s crest. The deformation process at the central area of the dam’s crest follows a continuous and non-disruptive pattern, which is consistent with the typical deformation behavior of the Xiaolangdi earth–rock dam structure. Therefore, it is judged that the current deformation of the Xiaolangdi Dam does not impact the safe operation of the dam. InSAR technology enables the rapid acquisition of high-precision, high-density deformation information on the surfaces of reservoir dams. With an increasing number of radar satellites in various frequency bands, such as Sentinel-1 and TerraSAR-X, there is now an ample supply of available data sources for InSAR applications. Consequently, InSAR technology can be extended to routine monitoring applications for reservoir dam deformations, especially for small and medium-sized reservoirs that may not be equipped with ground measurement tools like GNSS. This holds significant importance and potential for enhancing the safety monitoring of such reservoirs.

Inversion analysis of rock mass permeability coefficient of dam engineering based on particle swarm optimization and support vector machine: A case study

In order to efficiently and reasonably determine the permeability coefficient of engineering rock mass, the two key problems of complex seepage field simulation and objective function solution in permeability coefficient inversion are studied and improved. Firstly, a 3D refined seepage numerical model is established considering the main fault fracture zones and dam seepage control system. Secondly, combined with the support vector machine (SVM) algorithm, the complex mapping relationship between permeability coefficient of each rock layer and impervious structure and piezometer head is constructed. Finally, the particle swarm optimization (PSO) algorithm is introduced, and then the efficient optimization of permeability coefficient inversion of engineering rock mass and impervious structure is realized based on PSO-SVM. The case study of LJH arch dam shows that the inversion calculation framework based on PSO-SVM not only completes the rapid proxy calculation of the numerical model of complex seepage field, but also realizes the accurate optimization of the inversion objective function. The simulation results under the final inversion parameters reproduce the variation characteristics of the piezometric tube water level of each typical measuring point under the change of reservoir water level. In addition, with the correlation analysis between the permeability coefficient and the measured value of the corresponding piezometer, the parameter inversion method is endowed with new application value. This study is of great significance for clarifying the seepage characteristics of complex rock mass and improving the inversion efficiency of dam seepage monitoring data.

Factors affecting changes in water level and quality in a rural farmstead well

Factors affecting changes in water level and quality in a rural farmstead well

Relationship between pollination syndromes, pollen morphology and plant ecology in Quaternary deposits of the Cerrado

This study presents morphological descriptions and ecological information for 58 terrestrial pollen taxa and seven water-related pollen taxa from the Brazilian Cerrado, obtained from two sediment cores, Lake Feia (LFB1) and Getulio Swamp (VGE-17), encompassing the last 5000 and 15,000 cal yr BP, respectively. The relationships between the ecological and morphological traits (pollination syndrome, vegetation stratum and grain size) within each of the two depositional environments were investigated. In the LFB1 core, the pollen assemblages were dominated by arboreal pollen from closed physiognomies and lower storey trees (<10 m in height), while a combination of closed and open physiognomies was observed in the pollen assemblages from the VGE-17 core. The vast majority of the pollen taxa exhibited the entomophilous pollination syndrome, and a higher influx of entomophilous pollen was observed in both cores. Anemophilous and anemophilous/entomophilous syndromes were less well represented. Small and medium pollen grain classes were the most abundant, while the large pollen grain class was rare. The influx of small pollen grains was slightly more abundant in the lake record, while in the swamp record medium pollen grains were more abundant. Our results show that swamps and lakes differ in their representation of local versus regional pollen and in their sensitivity and responses to water-level changes. Landscape physiognomy also influences pollen dispersion: a closed physiognomy increases the local pollen signal, while a more open physiognomy results in better representation of local and regional signals.

Deformation warning index for reinforced concrete dam based on structural health monitoring data and numerical simulation

The material mechanical parameters of the dam body and foundation will change when a dam is reinforced during the aging process. This causes significant changes in the structural state of the project and makes it difficult to ensure its structural safety. In this study, a new deformation warning index for reinforced concrete dams was developed according to the prototype monitoring data, statistical models, three-dimensional finite element model (FEM) numerical simulation, and the critical conditions of the dam structure. A statistical model was established to separate the water pressure component. Then, a three-dimensional FEM of the reinforced concrete dam was constructed to simulate the water pressure component. Furthermore, the deformation components that affected the mechanical parameters of the dam under the same amount of reservoir water level change were separated and quantified accurately. In addition, the method for inversion of comprehensive mechanical parameters after dam reinforcement was used. The influence mechanisms of the deformation behavior of concrete dams under the reservoir water level and temperature changes were investigated. A new deformation warning index was developed by combining the forward-simulated critical water pressure component and temperature component in the period of extreme temperature decrease with the aging component separated by the statistical model. The new deformation warning index considers the structural state of the dam before and after reinforcement and links the structural strength criterion and the deformation evolution mechanisms. It provides a theoretical foundation and decision support for long-term service and operation management of reinforced dams.