scholarly journals Quantitative Impacts of Climate Change and Human Activities on Water-Surface Area Variations from the 1990s to 2013 in Honghu Lake, China

Water ◽  
2015 ◽  
Vol 7 (12) ◽  
pp. 2881-2899 ◽  
Author(s):  
Bianrong Chang ◽  
Rendong Li ◽  
Chuandong Zhu ◽  
Kequn Liu
Keyword(s):  
Climate Change ◽  
Surface Area ◽  
Human Activities ◽  
Water Surface ◽  
Water Surface Area ◽  
Honghu Lake ◽  
Impacts Of Climate Change

scholarly journals Impacts of Rapid Changes of Land Cover and Intensive Human Activities on Avarga Toson Lake Area, Mongolia

2020 ◽  
Vol 12 (15) ◽  
pp. 6070
Author(s):  
Urtnasan Mandakh ◽  
Danzanchadav Ganbat ◽  
Bayartungalag Batsaikhan ◽  
Sainbayar Dalantai ◽  
Zolzaya Adiya ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Surface Area ◽  
Human Activities ◽  
Water Surface ◽  
Land Development ◽  
Water Area ◽  
Lake Area ◽  
Surrounding Area ◽  
Water Surface Area

Avarga Toson Lake and its surrounding area are very important for people, wildlife, and animals in Delgerkhaan Soum of Khentii Province in Eastern Mongolia. Some research has been conducted so as to explore the medical nature and characteristics of the lake and its surrounding area. However, the adverse effects of land use have neither been studied nor reported. The fact that the water catchment area is shrinking evidences clearly that findings of various real-time studies must be used effectively in the long-term by the local government and relevant authorities in order to take immediate remedial measures. Our study focused on land cover changes occurring as a result of human activities in the area, using a Landsat imageries and water indices approach to estimate the changes of land use and land cover. The aims of this study were to assess the land use and cover change that occurred between 1989 and 2018 and to define the impacting factors on the changes of water surface area in Avarga Toson Lake area, Mongolia. Findings revealed that the water surface area has decreased by 34.1% in the past 30 years. The lake water area had the weakest, positive correlation with temperature and precipitation. We did not find any indicators suggesting a relationship between lake area and climate variables. In contrast, the area was slightly correlated with socio-economic variables, such as Toson Lake area with the number of visitors (R2 = 0.89) and Burd Lake area the with number of livestocks (R2 = 0.75), respectively. Therefore, the main conclusion of this paper is that socioeconomic factors driven by land use change, policy, and institutional failure together with the existing pressure on the lake may amplify their effect of the water surface area decreasing. Additionally, even if policy adoption is relatively sufficient in the country, the public institutional capacity to implement a successful sustainable land management model regarding land access, land development, land resources protection, land market, and investments in infrastructure remains very limited.

scholarly journals Monitoring the Seasonal Hydrology of Alpine Wetlands in Response to Snow Cover Dynamics and Summer Climate: A Novel Approach with Sentinel-2

2020 ◽  
Vol 12 (12) ◽  
pp. 1959
Author(s):  
Bradley Z. Carlson ◽  
Marie Hébert ◽  
Colin Van Reeth ◽  
Marjorie Bison ◽  
Idaline Laigle ◽  
...  
Keyword(s):  
Climate Change ◽  
Snow Cover ◽  
Surface Area ◽  
Water Surface ◽  
Alpine Wetland ◽  
Summer Climate ◽  
Water Surface Area ◽  
Summer Heat ◽  
Snow Cover Duration ◽  
Sentinel 2

Climate change in the European Alps during recent years has led to decreased snow cover duration as well as increases in the frequency and intensity of summer heat waves. The risk of drought for alpine wetlands and temporary pools, which rely on water from snowmelt and provide habitat for specialist plant and amphibian biodiversity, is largely unknown and understudied in this context. Here, we test and validate a novel application of Sentinel-2 imagery aimed at quantifying seasonal variation in water surface area in the context of 95 small (median surface area <100 m2) and shallow (median depth of 20 cm) alpine wetlands in the French Alps, using a linear spectral unmixing approach. For three study years (2016–2018), we used path-analysis to correlate mid-summer water surface area to annual metrics of snowpack (depth and duration) and spring and summer climate (temperature and precipitation). We further sought to evaluate potential biotic responses to drought for study years by monitoring the survival of common frog (Rana temporaria) tadpoles and wetland plant biomass production quantified using peak Normalized Difference Vegetation Index (NDVI). We found strong agreement between citizen science-based observations of water surface area and Sentinel-2 based estimates (R2 = 0.8–0.9). Mid-summer watershed snow cover duration and summer temperatures emerged as the most important factors regulating alpine wetland hydrology, while the effects of summer precipitation, and local and watershed snow melt-out timing were not significant. We found that a lack of summer snowfields in 2017 combined with a summer heat wave resulted in a significant decrease in mid-summer water surface area, and led to the drying up of certain wetlands as well as the observed mortality of tadpoles. We did not observe a negative effect of the 2017 summer on the biomass production of wetland vegetation, suggesting that wetlands that maintain soil moisture may act as favorable microhabitats for above treeline vegetation during dry years. Our work introduces a remote sensing-based protocol for monitoring the surface hydrology of alpine wetland habitats at the regional scale. Given that climate models predict continued reduction of snow cover in the Alps during the coming years, as well as particularly intense warming during the summer months, our conclusions underscore the vulnerability of alpine wetlands in the face of ongoing climate change.

scholarly journals Human Activities and Climate Variability Affecting Inland Water Surface Area in a High Latitude River Basin

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 382 ◽  
Author(s):  
Liwen Chen ◽  
Guangxin Zhang ◽  
Y. Jun Xu ◽  
Shengbo Chen ◽  
Yanfeng Wu ◽  
...  
Keyword(s):  
Surface Area ◽  
River Basin ◽  
High Latitude ◽  
Human Activities ◽  
Water Surface ◽  
Water Bodies ◽  
Total Water ◽  
Inland Water ◽  
Water Surface Area ◽  
Inland Water Bodies

Spatiotemporal changes in the surface area of inland water bodies have important implications in regional water resources, flood control, and drought hazard prediction. Although inland water bodies have been investigated intensively, few studies have looked at the effect of human activities and climate variability on surface area of inland waters at a larger scale over time and space. In this study, we used MODIS (MOD13Q1) images to determine water surface area extent at 250 m spatial resolution. We then applied this algorithm with MOD13Q1 images taken at 16-day intervals from 2000 to 2018 to a large river basin in China’s northeast high latitude region with dense stream network and abundant wetlands to investigate spatiotemporal distribution and dynamics of inland water bodies. The study identified 209 ponds, lakes, and reservoirs with an average total surface area of 2080 km2 in the past 19 years. The total water surface area fluctuated largely from 942 km2 to 5169 km2, corresponding to rainfall intensity and flood. We found that the total water surface area in this high latitude river basin showed an increasing trend during the study period, while the annual precipitation amount in the river basin also had an increasing trend concurrently. Precipitation and irrigation significantly contributed to the monthly change of water surface area, which reached the highest during June and August. The increase of water surface area was significant in the lower basin floodplain region, where agricultural irrigation using groundwater for rice production has progressed. Four nationally important wetland preserves (Zhalong, Xianghai, Momoge, and Chagan Lake) in the river basin made up nearly 50% of the basin’s total water surface area, of which Zhalong, Xianghai, and Momoge are designated by The Ramsar Convention as wetland sites of international importance. Seasonally, these water bodies reached their maximal surface area in August, when both the monsoon weather and agricultural discharge prevailed. This study demonstrates that water surface area in a high latitude river basin is affected by both human activities and climate variation, implying that high latitude regions will likely experience more changes in surface water distribution as global climate change continues and agriculture becomes intensified.

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