scholarly journals A review on the driving forces of water decline and its impacts on the environment in Poyang Lake, China

2020 ◽  
Author(s):  
Qiyue Li ◽  
Geying Lai ◽  
Adam Thomas Devlin
Keyword(s):  
Climate Change ◽  
Migratory Birds ◽  
Driving Forces ◽  
Poyang Lake ◽  
Ecological Impacts ◽  
Water Levels ◽  
Sand Mining ◽  
Potential Threat ◽  
Lake Ecosystems ◽  
Natural Lakes

Abstract The recession of water levels of natural lakes and their associated impacts on wetland ecosystems is a serious issue worldwide. Poyang Lake (the largest freshwater lake in China) has experienced a heightened and prolonged water decline since the year 2000, which causes concern for associated ecological impacts. In particular, climate change, operation of the Three Gorges Dam (TGD), and high magnitude sand mining appear to be well-correlated with the occurrence of water decline in Poyang Lake. Though the above factors have been analyzed in previous studies, a comprehensive summary has never been compiled. This paper provides a detailed literary review highlighting the driving forces and possible impacts of the consistent water decline in Poyang Lake. We conclude here that the operation of TGD is a fundamental cause for the lake water decline, aggravated by climate change and sand mining. The water decline has caused a deterioration of water quality, as well as having given rise to a potential threat to the habitat of migratory birds and Yangtze finless porpoises. The paper intends to offer constructive references that can be used in decision-making for effective protection of water resources and lake ecosystems.

scholarly journals Hydrological Characteristics of the Te Hapua Wetland Complex:The Potential Influence of Groundwater Level, Bore Abstraction and Climate Change on Wetland Surface Water Levels

2021 ◽  
Author(s):  
◽  
Craig Wayne Allen
Keyword(s):  
Climate Change ◽  
Surface Water ◽  
Groundwater Level ◽  
Hydrological Cycle ◽  
Shallow Groundwater ◽  
Water Levels ◽  
Groundwater Abstraction ◽  
Potential Threat ◽  
Through Flow ◽  
Future Viability

<p>Te Hapua is a complex of small, privately owned wetlands approximately 60 km northwest of Wellington. The wetlands represent a large portion of the region's remaining palustrine swamps, which have been reduced to just 1% of the pre-1900 expanse. Whilst many land owners have opted to protect wetlands on their land with covenants, questions have been raised regarding potential threats stemming from the wider region. Firstly, some regional groundwater level records have shown significant decline in the 10 to 25 years they have been monitored. The reason for this is unclear. Wetlands are commonly associated with groundwater discharge, so a decline in groundwater level could adversely affect wetland water input. Secondly, estimated groundwater resources are currently just 8% allocated, so there is potential for a 92% increase in groundwater abstraction from aquifers that underlie the wetlands. Finally, predictions of future climate change indicate changes in rainfall quantity and intensity. This would likely alter the hydrological cycle, impacting on rainfall dependant ecosystems such as wetlands as well as groundwater recharge. Whilst previous ecological surveys at Te Hapua provide valuable information on biodiversity and ecological threat, there has been no detailed study of the hydrology of the wetlands. An understanding of the relationship between the surface water of the wetlands and the aquifers that underlie the area is important when considering the future viability of the wetlands. This study aims to define the local hydrology and assess the potential threat of 'long term' groundwater level decline, increased groundwater abstraction and predicted climate change. Eleven months of water level data was supplied by Wellington Regional Council for three newly constructed Te Hapua wetland surface water and adjacent shallow groundwater monitoring sites. The data were analysed in terms of their relative water levels and response to rainfall. A basic water balance was calculated using the data from the monitoring sites and a GIS analysis of elevation data mapped the wetlands and their watersheds. A survey of 21 individual wetlands was carried out to gather water quality and water regime data to enable an assessment of wetland class. Historical groundwater level trends and geological records were analysed in the context of potential threat to the wetlands posed by a decline in groundwater level. Climate change predictions for the Kapiti Coast were reviewed and discussed in the context of possible changes to the hydrological cycle and to wetlands. Results from the wetland survey indicated that there are two distinct bands of wetlands at Te Hapua. Fens are found mostly in the eastern band and are more likely to be discharge wetlands, some of which are ephemeral. Swamps are found mostly in the western band and are more likely to be recharge wetlands. Dominant water input to fens is via local rainfall and local through-flow of shallow groundwater, especially from surrounding dunes. The eastern band of wetlands is typified by higher dunes and hence has greater input from shallow groundwater than wetlands in the western band. Dominant water input to swamps is via local rainfall, runoff, and through-flow from the immediate watershed and adjacent wetlands. Overall, the future viability of the Te Hapua wetland complex appears promising. Historical groundwater declines appear to be minimal and show signs of reversing. Abstraction from deep aquifers is not likely to impact on wetland water levels. Climate change is likely to have an impact on the hydrological cycle and may increase pressure on some areas, especially ephemeral wetlands. The effect of climate change on groundwater level is more difficult to forecast, but may lower water level in the long term.</p>

scholarly journals Study on the Causes of the Decline of the Low Water Levels of Poyang Lake, China

2019 ◽  
Vol 117 ◽  
pp. 00014
Author(s):  
Jian-Zhao Guan ◽  
Lei Zhang ◽  
Chun-Ming Fang ◽  
Jun Feng
Keyword(s):  
Water Level ◽  
Poyang Lake ◽  
Dominant Role ◽  
Water Environment ◽  
River Channel ◽  
Water Levels ◽  
Sand Mining ◽  
Channel Erosion ◽  
Main River Channel ◽  
Water Level Decline

The drastic decline in the water level of Poyang Lake during the dry season has close connection with the water environment and lake ecology. The drastic decline has attracted considerable attention, and has led to intense scientific discussions regarding its cause. However, the importance of the different causes of the low water level decline has not been clearly illustrated. To improve the understanding of the reasons for the decline of low water levels in the Poyang Lake Waterway, this paper investigated the contributions of river channel erosion and sand mining to the water level decline. The results show that sand mining mainly occurred on the beaches of the Waterway, and had a relatively small effect on the change in the shape of the main river channel. It was found that the contribution of sand mining to the decline in the low water level was no more than 30%, while the average contribution by natural erosion was about 85%. This indicates that natural channel erosion of the Waterway has been significant, and plays a dominant role in the declining water levels of the Waterway.

scholarly journals Hydrological Characteristics of the Te Hapua Wetland Complex:The Potential Influence of Groundwater Level, Bore Abstraction and Climate Change on Wetland Surface Water Levels

2021 ◽  
Author(s):  
◽  
Craig Wayne Allen
Keyword(s):  
Climate Change ◽  
Surface Water ◽  
Groundwater Level ◽  
Hydrological Cycle ◽  
Shallow Groundwater ◽  
Water Levels ◽  
Groundwater Abstraction ◽  
Potential Threat ◽  
Through Flow ◽  
Future Viability

<p>Te Hapua is a complex of small, privately owned wetlands approximately 60 km northwest of Wellington. The wetlands represent a large portion of the region's remaining palustrine swamps, which have been reduced to just 1% of the pre-1900 expanse. Whilst many land owners have opted to protect wetlands on their land with covenants, questions have been raised regarding potential threats stemming from the wider region. Firstly, some regional groundwater level records have shown significant decline in the 10 to 25 years they have been monitored. The reason for this is unclear. Wetlands are commonly associated with groundwater discharge, so a decline in groundwater level could adversely affect wetland water input. Secondly, estimated groundwater resources are currently just 8% allocated, so there is potential for a 92% increase in groundwater abstraction from aquifers that underlie the wetlands. Finally, predictions of future climate change indicate changes in rainfall quantity and intensity. This would likely alter the hydrological cycle, impacting on rainfall dependant ecosystems such as wetlands as well as groundwater recharge. Whilst previous ecological surveys at Te Hapua provide valuable information on biodiversity and ecological threat, there has been no detailed study of the hydrology of the wetlands. An understanding of the relationship between the surface water of the wetlands and the aquifers that underlie the area is important when considering the future viability of the wetlands. This study aims to define the local hydrology and assess the potential threat of 'long term' groundwater level decline, increased groundwater abstraction and predicted climate change. Eleven months of water level data was supplied by Wellington Regional Council for three newly constructed Te Hapua wetland surface water and adjacent shallow groundwater monitoring sites. The data were analysed in terms of their relative water levels and response to rainfall. A basic water balance was calculated using the data from the monitoring sites and a GIS analysis of elevation data mapped the wetlands and their watersheds. A survey of 21 individual wetlands was carried out to gather water quality and water regime data to enable an assessment of wetland class. Historical groundwater level trends and geological records were analysed in the context of potential threat to the wetlands posed by a decline in groundwater level. Climate change predictions for the Kapiti Coast were reviewed and discussed in the context of possible changes to the hydrological cycle and to wetlands. Results from the wetland survey indicated that there are two distinct bands of wetlands at Te Hapua. Fens are found mostly in the eastern band and are more likely to be discharge wetlands, some of which are ephemeral. Swamps are found mostly in the western band and are more likely to be recharge wetlands. Dominant water input to fens is via local rainfall and local through-flow of shallow groundwater, especially from surrounding dunes. The eastern band of wetlands is typified by higher dunes and hence has greater input from shallow groundwater than wetlands in the western band. Dominant water input to swamps is via local rainfall, runoff, and through-flow from the immediate watershed and adjacent wetlands. Overall, the future viability of the Te Hapua wetland complex appears promising. Historical groundwater declines appear to be minimal and show signs of reversing. Abstraction from deep aquifers is not likely to impact on wetland water levels. Climate change is likely to have an impact on the hydrological cycle and may increase pressure on some areas, especially ephemeral wetlands. The effect of climate change on groundwater level is more difficult to forecast, but may lower water level in the long term.</p>

scholarly journals Integrated model projections of climate change impacts on water-level dynamics in the large Poyang Lake (China)

2019 ◽  
Author(s):  
Yunliang Li ◽  
Qi Zhang ◽  
Hui Tao ◽  
Jing Yao
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Lake Water ◽  
Hydrological Model ◽  
Poyang Lake ◽  
Baseline Period ◽  
Global Climate Models ◽  
Water Levels ◽  
Future Climate Change ◽  
Increased Risk

Abstract This study outlines a framework for examining potential impacts of future climate change in Poyang Lake water levels using linked models. The catchment hydrological model (WATLAC) was used to simulate river runoffs from a baseline period (1986–2005) and near-future (2020–2035) climate scenarios based on eight global climate models (GCMs). Outputs from the hydrological model combined with the Yangtze River's effects were fed into a lake water-level model, developing in the back-propagation neural network. Model projections indicate that spring–summer water levels of Poyang Lake are expected to increase by 5–25%, and autumn–winter water levels are likely to be lower and decrease by 5–30%, relative to the baseline period. This amounts to higher lake water levels by as much as 2 m in flood seasons and lower water levels in dry seasons in the range of 0.1–1.3 m, indicating that the lake may be wet-get-wetter and dry-get-drier. The probability of occurrence for both the extreme high and low water levels may exhibit obviously increasing trends by up to 5% more than at present, indicating an increased risk in the severity of lake floods and droughts. Projected changes also include possible shifts in the timing and magnitude of the lake water levels.

scholarly journals Assessing Hydrological and Sedimentation Effects from Bottom Topography Change in a Complex River–Lake System of Poyang Lake, China

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1489 ◽  
Author(s):  
Xuchun Ye ◽  
Qiang Guo ◽  
Zengxin Zhang ◽  
Chongyu Xu
Keyword(s):  
Lake Water ◽  
Poyang Lake ◽  
Bottom Topography ◽  
Water Security ◽  
Water Levels ◽  
Lake Ecosystem ◽  
Mining Activities ◽  
Sand Mining ◽  
Lake Bottom ◽  
Outflow Channel

In recent years, a dramatic decline in Poyang Lake water levels and a shrinking water surface have raised concerns about water security and the wetland ecosystem. Changes in bottom topography due to sand mining activities in the lake was supposed to be one of the influencing factors of these changes. In response to this issue, the current study analyzed the change of lake bottom topography from observed digital elevation model (DEM) data, and quantitatively assessed the spatial and temporal responses of lake hydrology based on the framework of the neural network and the sediment effect was examined afterward. Results showed a total volume of 11.54 × 108 m3/year (about 0.96 × 108 m3/year or 1.58 × 108 t/year sediment) in net change of lake bottom topography in recent years, among which 97% was directly exported by commercial sand mining. During the study period, 2000–2011, intensive sand mining extended the central part of Poyang Lake and widened and deepened the outflow channel of the northern lake. This great change of lake bottom topography caused an average annual increase of 182.74 m3/s of lake outflow and a decline of 0.23 m–0.61 m in water levels across the lake. However, lake water levels are not consistent and show remarkable spatial and seasonal differences. The effects of changes in lake bottom topography on lake hydrological processes continue to grow as sand mining activities in the lake continue. More research on the environmental impacts is required for sustainable management of the lake ecosystem.

scholarly journals Economic damages from Hurricane Sandy attributable to sea level rise caused by anthropogenic climate change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Benjamin H. Strauss ◽  
Philip M. Orton ◽  
Klaus Bittermann ◽  
Maya K. Buchanan ◽  
Daniel M. Gilford ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
East Coast ◽  
The United States ◽  
Hurricane Sandy ◽  
Water Levels ◽  
Anthropogenic Climate Change ◽  
Economic Damage ◽  
Sea Levels

AbstractIn 2012, Hurricane Sandy hit the East Coast of the United States, creating widespread coastal flooding and over $60 billion in reported economic damage. The potential influence of climate change on the storm itself has been debated, but sea level rise driven by anthropogenic climate change more clearly contributed to damages. To quantify this effect, here we simulate water levels and damage both as they occurred and as they would have occurred across a range of lower sea levels corresponding to different estimates of attributable sea level rise. We find that approximately $8.1B ($4.7B–$14.0B, 5th–95th percentiles) of Sandy’s damages are attributable to climate-mediated anthropogenic sea level rise, as is extension of the flood area to affect 71 (40–131) thousand additional people. The same general approach demonstrated here may be applied to impact assessments for other past and future coastal storms.

scholarly journals Multiple climate change-driven tipping points for coastal systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Patrick L. Barnard ◽  
Jenifer E. Dugan ◽  
Henry M. Page ◽  
Nathan J. Wood ◽  
Juliette A. Finzi Hart ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Adaptation ◽  
Sandy Beaches ◽  
Local Economy ◽  
Water Levels ◽  
Tipping Points ◽  
Socioeconomic Impacts ◽  
Hazard Exposure ◽  
Coastal Systems ◽  
Projected Changes

AbstractAs the climate evolves over the next century, the interaction of accelerating sea level rise (SLR) and storms, combined with confining development and infrastructure, will place greater stresses on physical, ecological, and human systems along the ocean-land margin. Many of these valued coastal systems could reach “tipping points,” at which hazard exposure substantially increases and threatens the present-day form, function, and viability of communities, infrastructure, and ecosystems. Determining the timing and nature of these tipping points is essential for effective climate adaptation planning. Here we present a multidisciplinary case study from Santa Barbara, California (USA), to identify potential climate change-related tipping points for various coastal systems. This study integrates numerical and statistical models of the climate, ocean water levels, beach and cliff evolution, and two soft sediment ecosystems, sandy beaches and tidal wetlands. We find that tipping points for beaches and wetlands could be reached with just 0.25 m or less of SLR (~ 2050), with > 50% subsequent habitat loss that would degrade overall biodiversity and ecosystem function. In contrast, the largest projected changes in socioeconomic exposure to flooding for five communities in this region are not anticipated until SLR exceeds 0.75 m for daily flooding and 1.5 m for storm-driven flooding (~ 2100 or later). These changes are less acute relative to community totals and do not qualify as tipping points given the adaptive capacity of communities. Nonetheless, the natural and human built systems are interconnected such that the loss of natural system function could negatively impact the quality of life of residents and disrupt the local economy, resulting in indirect socioeconomic impacts long before built infrastructure is directly impacted by flooding.

scholarly journals The effects of ENSO, climate change and human activities on the water level of Lake Toba, Indonesia: a critical literature review

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hendri Irwandi ◽  
Mohammad Syamsu Rosid ◽  
Terry Mart
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Human Activities ◽  
Southern Oscillation ◽  
Climatic Conditions ◽  
Water Levels ◽  
Dominant Factor ◽  
Climate Projections ◽  
Continuous Increase ◽  
The Future

AbstractThis research quantitatively and qualitatively analyzes the factors responsible for the water level variations in Lake Toba, North Sumatra Province, Indonesia. According to several studies carried out from 1993 to 2020, changes in the water level were associated with climate variability, climate change, and human activities. Furthermore, these studies stated that reduced rainfall during the rainy season due to the El Niño Southern Oscillation (ENSO) and the continuous increase in the maximum and average temperatures were some of the effects of climate change in the Lake Toba catchment area. Additionally, human interventions such as industrial activities, population growth, and damage to the surrounding environment of the Lake Toba watershed had significant impacts in terms of decreasing the water level. However, these studies were unable to determine the factor that had the most significant effect, although studies on other lakes worldwide have shown these factors are the main causes of fluctuations or decreases in water levels. A simulation study of Lake Toba's water balance showed the possibility of having a water surplus until the mid-twenty-first century. The input discharge was predicted to be greater than the output; therefore, Lake Toba could be optimized without affecting the future water level. However, the climate projections depicted a different situation, with scenarios predicting the possibility of extreme climate anomalies, demonstrating drier climatic conditions in the future. This review concludes that it is necessary to conduct an in-depth, comprehensive, and systematic study to identify the most dominant factor among the three that is causing the decrease in the Lake Toba water level and to describe the future projected water level.

scholarly journals Breathing space: deoxygenation of aquatic environments can drive differential ecological impacts across biological invasion stages

2021 ◽  
Author(s):  
James W. E. Dickey ◽  
Neil E. Coughlan ◽  
Jaimie T. A. Dick ◽  
Vincent Médoc ◽  
Monica McCard ◽  
...  
Keyword(s):  
Climate Change ◽  
Oxygen Saturation ◽  
Ecological Impacts ◽  
Neogobius Melanostomus ◽  
Aquatic Environments ◽  
Relative Impact ◽  
Low Oxygen ◽  
Per Capita ◽  
The Impact ◽  
Prey Populations

AbstractThe influence of climate change on the ecological impacts of invasive alien species (IAS) remains understudied, with deoxygenation of aquatic environments often-overlooked as a consequence of climate change. Here, we therefore assessed how oxygen saturation affects the ecological impact of a predatory invasive fish, the Ponto-Caspian round goby (Neogobius melanostomus), relative to a co-occurring endangered European native analogue, the bullhead (Cottus gobio) experiencing decline in the presence of the IAS. In individual trials and mesocosms, we assessed the effect of high, medium and low (90%, 60% and 30%) oxygen saturation on: (1) functional responses (FRs) of the IAS and native, i.e. per capita feeding rates; (2) the impact on prey populations exerted; and (3) how combined impacts of both fishes change over invasion stages (Pre-invasion, Arrival, Replacement, Proliferation). Both species showed Type II potentially destabilising FRs, but at low oxygen saturation, the invader had a significantly higher feeding rate than the native. Relative Impact Potential, combining fish per capita effects and population abundances, revealed that low oxygen saturation exacerbates the high relative impact of the invader. The Relative Total Impact Potential (RTIP), modelling both consumer species’ impacts on prey populations in a system, was consistently higher at low oxygen saturation and especially high during invader Proliferation. In the mesocosm experiment, low oxygen lowered RTIP where both species were present, but again the IAS retained high relative impact during Replacement and Proliferation stages at low oxygen. We also found evidence of multiple predator effects, principally antagonism. We highlight the threat posed to native communities by IAS alongside climate-related stressors, but note that solutions may be available to remedy hypoxia and potentially mitigate impacts across invasion stages.

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