Changes In Water Surface Area Research Articles

Detection of Changes in Water Surface Area in Limboto Lake Using Landsat Data From 1990 to 2020

Lake Limboto is included in the fifteen priority lakes due to its increasingly critical condition. Long-term observations of changes in the lake water surface area are carried out to understand the impact of changes better and protect the ecosystem of water resources. The use of remote sensing technology products in Landsat 4 TM, Landsat 5 TM, Landsat 7 ETM +, and Landsat 8 OLI satellite images and Google Earth Engine is a suitable combination to study the dynamics of Lake Limboto. The water index used are NDWI (Normalized Difference Water Index), MNDWI (Modified Normalized Difference Water Index), and AWEI (Automated Water Extraction Index). The water surface area of Lake Limboto changes every year, starting in 1990 with an area of 1,976 Ha, increasing in 2000 to 2,039 Ha, and the widest inundation of water surface in 2002 was 2,889 Ha, a decrease occurred in 2009 to 2,498 Ha, to become 1,843 Ha in 2020. The objects above the water surface also change yearly, from 6% in 1990-2000, increasing to 10% in 2009, reaching a 16% increase in 2014, and decreasing to 9% in 2020. This changing trend can be used as the basis for government policies in the management of Limboto Lake.

Temporal and Spatial Evolution of Eichmann Lake Wetland in Aksu River Basin and Its Response to Ecological Water Supply.

Timely understanding and quantitative analysis of the changing trend in natural ecosystems in arid and semi-arid areas and their response to the ecological water supply process are of great significance for maintaining the health of oasis ecosystems. Taking the Eichmann Lake wetland of the Aksu River Basin in Xinjiang as the research area, the temporal-spatial distribution characteristics of the lake and the response of ecological water in recent years were studied based on remote sensing images and monitoring data. The results show that: (1) The water surface area of Eichmann Lake is shrinking, from 61.57 km2 in 1996 to 27.76 km2 in 2020. The changes in water surface area have experienced three stages: rapid decline, slow decline, and slow recovery. After the ecological water supply, the water surface area has obvious seasonal changes with hysteresis; (2) In areas with a low average water level, the ecological water supply has a significant impact on the groundwater level. The higher the water supply is, the higher the groundwater level will be. There is a significant lag effect between the change in the groundwater level and the response of the ecological water supply, which is 1-2 months; (3) The response characteristics of different natural vegetation to the ecological water supply were different in interannual, seasonal, and spatial contexts. The response of Populus euphratica to the ecological water supply is obvious, and its growth is the best within the range of 100-500 m from the water supply outlet. This research can provide the basis for the rational allocation of the Aksu River Basin's water resources, and also act as a valuable reference for the restoration and reconstruction of surrounding vegetation in the Aksu River irrigation area.

Detectability of variation in river flood from satellite images

Floods are major natural disasters that have considerable consequences worldwide. As the frequency and magnitude of flooding are expected to be affected by ongoing climate change, understanding their past changes is important for developing adequate adaptation measures. However, the limited spatiotemporal coverage of flood gauges hinders detection of changes in flooding, particularly in poorly gauged regions. Here, we propose a method using surface water data of river floodplain inundation as a proxy of the magnitude and frequency of flooding. Surface water data − Aqua Monitor which represented the probability linear trend changes in land and water surface area based on 30-m Landsat images between 1984–2000 and 2000–2013 was used in this study. The changes in water surface area over the floodplain obtained from Aqua Monitor showed high correspondence with historical trends observed or simulated annual maximum daily discharge, indicating the potential to detect changes in frequency and magnitude of flood from satellite data. In regions where changes could be measured with sufficient satellite images, 29% showed an increase in water surface area in the flood plain, 41% showed a decrease, and 30% showed small or no changes.

Water, water, but not everywhere: analysis of shrinking water bodies using open access satellite data

ABSTRACT The importance of water cannot be overstated. Not only it is essential for life, it is a vital resource for sustainable development. Water resource management is pivotal to ensure water security and sustainability. Having such water monitoring resources is challenging, especially in less developed countries that have limited resources. With the advancement in technology and availability of open-access satellite data, there are opportunities to reinforce the abilities of researchers and decision-makers to monitor and identify changes in water resources. In this work, we describe an easy to implement workflow for estimation of surface area of waterbodies using open-access data from Sentinel-2 satellites. The method uses Normalized Difference Water Index (NDWI) for surface water detection that is used to estimate the surface area of the waterbody and analyse changes over a period of time. We develop four case studies based on waterbodies in Spain, Morocco, and India to highlight how satellite imaging can effectively help in estimating and visualizing the changes in water surface area. Temperature and rainfall data are analysed to understand the impact of climate change on water resources due to increase in temperature and changes in precipitation patterns. The proposed method is validated by testing it on four additional lakes and comparing the results with publicly available data. We show how open-access satellite data can potentially be used for regular monitoring of waterbodies as well as filling the knowledge gap to assist in decision making at both local and regional levels.

Google earth engine application for estimating changes in water surface area of Lake Toba

The change in the water surface area is essential to be studied as it can affect ecosystem health and function of lakes to meet human needs. The use of remote sensing techniques is to analyze such changes in the Lake Toba is considered effective and efficient ways in terms of time and cost, moreover the application of Google Earth Engine (GEE) as an internet-based data processing platform (cloud computing) that provides various kinds of free satellite image data can simplify the process. In this study, the author aims to estimate the rate of change in the surface water area of Lake Toba in four periods, that are the period of 1990 – 1997, 1998 – 2004, 2005 – 2012, and 2013 – 2018, by using Landsat 5 TM and 8 OLI/TIRS imagery. Cloud masking methods is used to obtain cloud-free images and then using CART method in making land cover maps. After that, calculating the accuracy of CART method by using the confusion matrix to determine the Cohen’s Kappa coefficient value. The results of this study show that the highest lake surface water area is in the period of 1990 - 1997 within the area of 1133.88 km2, and the lowest one is in the periode of 1998 - 2004 within the area of 1119.20 km2. The correlation of land cover classes with a surface water area of Lake Toba shows that the open land has high correlation value of -0.77.

Changes in Water Surface Area of the Lake in the Steppe Region of Mongolia: A Case Study of Ugii Nuur Lake, Central Mongolia

The Ugii Nuur Lake is not only one of the small hydrologically closed lakes located in the Orkhon River Basin in Central Mongolia but also the most vulnerable area for global climate change. Therefore, this study aims to investigate the impacts of recent global climate change on the water surface area. The data we analyzed were various measured hydro-meteorological variables of the lake basin and the lake surface area, which was estimated from Landsat series satellite data from 1986 to 2018. The methods we used were Mann-Kendall (MK), Innovative trend analysis method (ITAM), Sen’s slope estimator test, correlation, and regression analysis. The variation of lake water surface area has a strong positive correlation with the change of the lake water level (r = 0.95). The Mann-Kendall trend analysis has indicated that under a significant decrease in total annual precipitation ( Z = −0.902) and inflow river discharge ( Z = −5.392) and a considerable increase in total annual evaporation ( Z = 4.385) and annual average air temperature ( Z = 4.595), the surface area of the Ugii Nuur Lake has decreased sharply ( Z = −6.021). The total annual evaporation (r = −0.64) and inflow river discharge (r = 0.67) were the essential hydro-meteorological factors affecting the surface area of the Ugii Nuur Lake. The lake surface area decreased by 13.5% in 2018 compared with 1986. In the near future, it is vital to conduct scientific studies considering the volume of lake water, groundwater, and the anthropogenic impact.

Effect of water surface area on the remotely sensed water quality parameters of Baysh Dam Lake, Saudi Arabia

Abstract. Water quality parameters help to decide the further use of water based on its quality. Changes in water surface area in the lake shall affect the water quality. Chlorophyll a, Nitrate concentration and water turbidity were extracted from satellite images to record each variation on these parameters caused by the water amount in the lake changes. Each water quality measures have been recorded with its surface area reading to analyses the effects. Water quality parameters were estimated from Sentinel-2 sensor based on the satellite temporal resolution for the years 2017–2018. Data were pre-processed then processed to estimate the Maximum Chlorophyll Index (MCI), Green Normalized Difference Vegetation Index (GNDVI) and Normalized Difference Turbidity Index (NDTI). The Normalized Difference Water Index (NDWI), was used to calculate and record the changes in the water surface area in Baysh dam lake. Results showed different correlation coefficients between the lake surface area and the water quality parameters estimated Remote Sensing data. The response of the water quality parameters to surface water changes was expressed in four different surface water categories. MCI is more sensitive to surface water changes rather than GNDVI and NDTI. Neural network Analysis showed a resemblance between GNDVI and NDTI expressed in sigmoidal function while MCI showed a different behavior expressed in exponential behavior. Therefore, monitoring of the surface water area of the lack is essential in water quality monitoring.

Changes in Water Surface Area during 1989–2017 in the Huai River Basin using Landsat Data and Google Earth Engine

The dynamics of surface water play a crucial role in the hydrological cycle and are sensitive to climate change and anthropogenic activities, especially for the agricultural zone. As one of the most populous areas in China’s river basins, the surface water in the Huai River Basin has significant impacts on agricultural plants, ecological balance, and socioeconomic development. However, it is unclear how water areas responded to climate change and anthropogenic water exploitation in the past decades. To understand the changes in water surface areas in the Huai River Basin, this study used the available 16,760 scenes Landsat TM, ETM+, and OLI images in this region from 1989 to 2017 and processed the data on the Google Earth Engine (GEE) platform. The vegetation index and water index were used to quantify the spatiotemporal variability of the surface water area changes over the years. The major results include: (1) The maximum area, the average area, and the seasonal variation of surface water in the Huai River Basin showed a downward trend in the past 29 years, and the year-long surface water areas showed a slight upward trend; (2) the surface water area was positively correlated with precipitation (p < 0.05), but was negatively correlated with the temperature and evapotranspiration; (3) the changes of the total area of water bodies were mainly determined by the 216 larger water bodies (>10 km2). Understanding the variations in water body areas and the controlling factors could support the designation and implementation of sustainable water management practices in agricultural, industrial, and domestic usages.

Variations of the glacier mass balance and lake water storage in the Tarim Basin, northwest China, over the period of 2003–2009 estimated by the ICESat-GLAS data

Accurately estimating the changes in glacier mass balance and water storage in lakes and reservoirs is critical to studying the water cycle in the inland river basin in northwest China. We used high-resolution satellite images to analyze the changes in water surface area of lakes and reservoirs in Tarim Basin, and used the ICESat-GLAS altimeter data to estimate their water level changes and the glacier mass balance change, over the period 2003–2009. The results showed the average glacier thinning in the entire basin was at a rate of 0.34 ± 0.25 m w.e./year equivalent height of water, which means that the glacier mass balance occurred −6.8 ± 1.2 km3 water equivalent over the study period. However, the mean water level of nearby lakes decreased by 0.41 ± 0.2 m even with the influx of glacial melt water, indicating that the lake level declines were caused by the withdrawal of lake water for human activities.

Visualization of Lake Mead Surface Area Changes from 1972 to 2009

For most of the last decade, the south-western portion of the United States has experienced a severe and enduring drought. This has caused serious concerns about water supply and management in the region. In this research, 30 orthorectified Landsat satellite images from the United States Geological Service (USGS) Earth Explorer archive were analyzed for the 1972 to 2009 period. The images encompassed Lake Mead (a major reservoir in this region) and were examined for changes in water surface area. Decadal lake area minimums/maximums were achieved in 1972/1979, 1981/1988, 1991/1998, and 2009/2000. The minimum lake area extent occurred in 2009 (356.4 km2), while the maximum occurred in 1998 (590.6 km2). Variable trends in water level and lake area were observed throughout the analysis period, however progressively lower values were observed since 2000. The Landsat derived lake areas show a very strong relationship with actual measured water levels at the Hoover Dam. Yearly water level variations at the dam vary minimally from the satellite derived estimates. A complete (yearly) record of satellite images may have helped to reduce the slight deviations in the time series.

Evaluating water resource maintenance for lakes of the middle Doce river

The importance of water resources to mankind and the threat level these resources have withstood due to regional and worldwide human intervention are undeniable. In the middle stretch of the Doce river basin, there are close to 170 natural lakes, located between an environmental conservation area and monoculture eucalyptus plantations, with social, economic and biological importance. Our objective was to evaluate whether the water surface area in these lakes has remained constant in the last few decades, and make inferences on the result. To that end, we measured the water surface area of 16 lakes, from satellite images obtained between May and August in the years 1977, 1979, 1981, 2000 and 2005. Total water surface area was compared considering these dates the two different areas. We did not find any changes in water surface area for these lakes in the studied images. Likewise, we did not observe reductions in any single lake for any of the studied areas. These results indicate hydrological constancy of the system, as well as of the services this group of lakes provides to society and biodiversity in its vicinity, regardless of whether the environmental matrix consists of old-growth vegetation or eucalyptus plantations.

Biodiversity changes in the lakes of the Central Yangtze

The Central Yangtze ecoregion in China includes a number of lakes, but these have been greatly affected by human activities over the past several decades, resulting in severe loss of biodiversity. In this paper, we document the present distribution of the major lakes and the changes in size that have taken place over the past 50 years, using remote sensing data and historical observations of land cover in the region. We also provide an overview of the changes in species richness, community composition, population size and age structure, and individual body size of aquatic plants, fishes, and waterfowl in these lakes. The overall species richness of aquatic plants found in eight major lakes has decreased substantially during the study period. Community composition has also been greatly altered, as have population size and age and individual body size in some species. These changes are largely attributed to the integrated effects of lake degradation, the construction of large hydroelectric dams, the establishment of nature reserves, and lake restoration practices.