The Cambodian Mekong floodplain under the future development plans and climate change

Abstract. Water infrastructure development is crucial for driving economic growth in the developing countries of the Mekong. Yet it may also alter existing hydrological and flood conditions, with serious implications for water management, agricultural production and ecosystem services, especially in the floodplain regions. Our current understanding of the hydrological and flood pattern changes associated with infrastructural development still contain several knowledge gaps, such as the consideration of overlooked prospective drivers, and the interactions between multiple drivers. This research attempts to conduct a cumulative impact assessment of flood changes in the Cambodian part of the Mekong floodplains. The developmental activity of six central sectors (hydropower, irrigation, navigation, flood protection, agricultural land use and water use) as well as climate change were considered in our modelling analysis. Our results show that the monthly, sub-seasonal, and seasonal hydrological regimes will be subject to substantial alterations under the 2020 planned development scenario, and even larger alterations under the 2040 planned development scenario. The degree of hydrological alteration under the 2040 planned development is somewhat counteracted by the effect of climate change, as well as the removal of mainstream dams in the Lower Mekong Basin and hydropower mitigation investments. The likely impact of decreasing water discharge in the early wet season (up to −34 %) will pose a critical challenge to rice production, whereas the likely increase in water discharge in the mid-dry season (up to +54 %) indicates improved water availability for coping with drought stresses and sustaining environmental flow. At the same time, these changes would have drastic impacts on total flood extent, which is projected to decline up to −18 %, having potentially negative impacts on floodplain productivity whilst at the same time reducing the flood risk to the area. Our findings urge the timely establishment of adaptation and mitigation strategies to manage such future environmental alterations in a sustainable manner.

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Evidence of Phosphate Mining and Agriculture Influence on Concentrations, Forms, and Ratios of Nitrogen and Phosphorus in a Florida River

Water ◽

10.3390/w13081064 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1064

Author(s):

Shuiwang Duan ◽

Kamaljit Banger ◽

Gurpal S. Toor

Keyword(s):

Agricultural Land ◽

Water Discharge ◽

Mining Area ◽

Specific Conductance ◽

Organic N ◽

Wet Season ◽

Nitrogen And Phosphorus ◽

Total N ◽

Phosphate Mining ◽

Molar Ratios

Florida has a long history of phosphate-mining, but less is known about how mining affects nutrient exports to coastal waters. Here, we investigated the transport of inorganic and organic forms of nitrogen (N) and phosphorus (P) over 23 sampling events during a wet season (June–September) in primary tributaries and mainstem of Alafia River that drains into the Tampa Bay Estuary. Results showed that a tributary draining the largest phosphate-mining area (South Prong) had less flashy peaks, and nutrients were more evenly exported relative to an adjacent tributary (North Prong), highlighting the effectiveness of the mining reclamation on stream hydrology. Tributaries draining > 10% phosphate-mining area had significantly higher specific conductance (SC), pH, dissolved reactive P (DRP), and total P (TP) than tributaries without phosphate-mining. Further, mean SC, pH, and particulate reactive P were positively correlated with the percent phosphate-mining area. As phosphate-mining occurred in the upper part of the watershed, the SC, pH, DRP, and TP concentrations increased downstream along the mainstem. For example, the upper watershed contributed 91% of TP compared to 59% water discharge to the Alafia River. In contrast to P, the highest concentrations of total N (TN), especially nitrate + nitrite (NOx–N) occurred in agricultural tributaries, where the mean NOx–N was positively correlated with the percent agricultural land. Dissolved organic N was dominant in all streamwaters and showed minor variability across sites. As a result of N depletion and P enrichment, the phosphate-mining tributaries had significantly lower molar ratios of TN:TP and NOx–N:DRP than other tributaries. Bi-weekly monitoring data showed consistent increases in SC and DRP and a decrease in NOx–N at the South Prong tributary (highest phosphate-mining area) throughout the wet season, and different responses of dissolved inorganic nutrients (negative) and particulate nutrients (positive) to water discharge. We conclude that (1) watersheds with active and reclaimed phosphate-mining and agriculture lands are important sources of streamwater P and N, respectively, and (2) elevated P inputs from the phosphate-mining areas altered the N:P ratios in streamwaters of the Alafia River.

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KEBANGKITAN LADANG BERPINDAH DI NAGARI SILAYANG KECAMATAN MAPATTUNGGUL SELATAN KABUPATEN PASAMAN PROVINSI SUMATERA BARAT

SOCA: Jurnal Sosial Ekonomi Pertanian ◽

10.24843/soca.2020.v14.i01.p01 ◽

2020 ◽

Vol 14 (1) ◽

pp. 1

Author(s):

Juli Yusran ◽

Yonariza Yonariza ◽

Elfindri Elfindri ◽

Mahdi Mahdi

Keyword(s):

Natural Disasters ◽

Shifting Cultivation ◽

Agricultural Land ◽

Infrastructure Development ◽

Qualitative And Quantitative ◽

Forest Clearing ◽

Key Informant ◽

Negative Impacts ◽

Food Needs ◽

Impact On Biodiversity

Infrastructure development and ProRLK (deforested Land Rehabilitation Project) a Government of Indonesia collaboration prpject with The German Technical Coorperation Agency (GTZ) in 1992, has shifted the pattern of shifting cultivation to rubber farming in Nagari Silayang. Households engaged in shifting cultivation for food needs, stopped this entrenched practice, and focused on rubber plantations for food needs and financial means. But in recent years, the practice of shifting cultivation has been rife in Nagari Silayang. This phenomenon refutes the theory of agricultural transformastion in many previous studies, which concluded that shifting agricultural patterns lead to patterns that increasingly leave shifting cultivation. The purpose of this study, is to find the factors that cause farm households in Nagari Silayang to return to shifting cultivation, and find ways or strategies to stop forest clearing for swidden land. The research method used is descriptive qualitative and quantitative. Data collection uses observation, key informant interviews and household surveys. the results showed that the revival of shifting cultivation in Nagari Silayang was caused by the decline in global rubber prices, maintaining food security, and efforts to increase household income. This will have an impact on biodiversity damage and even natural disasters, because old forests are converted to agricultural land. This leads to negative impacts on biodiversity and can result in natural disasters, as old forests are converted to agricultural land.

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MANGROVE ECOSYSTEM AND CLIMATE CHANGE MITIGATION: A LITERATURE REVIEW

Jurnal Sains dan Teknologi Mitigasi Bencana ◽

10.29122/jstmb.v16i1.4979 ◽

2021 ◽

Vol 16 (1) ◽

pp. 1-8

Author(s):

Dian Nuraini Melati

Keyword(s):

Climate Change ◽

Agricultural Land ◽

Mangrove Ecosystem ◽

Infrastructure Development ◽

Mangrove Forests ◽

Adaptation To Climate Change ◽

High Productivity ◽

Deforestation Rates ◽

Port Construction ◽

Change Mitigation

Mangrove ecosystem has high productivity both ecologically and economically. Mangroveecosystems have the ability to store high carbon which is useful in supporting the reduction ofgreenhouse gas emissions. The results of previous studies have shown that mangroveecosystems are able to store carbon three to four times greater than terestrial forests. Most ofthe carbon are stored in the soil. Therefore, ecosystem mangroves have an important role tomitigate climate change. However, mangroves can be effective in supporting the mitigation ofcarbon dioxide emissions if mangrove deforestation rates are low. However, mangroves canstill contribute with great potential when conservation are maintained to increase future carbonstocks through restoration and prevent further emissions from deforestation. Existing data andprior research indicate that mangrove forests are threatened due to mangrove coveragereduction. This is caused by changes in land use. There are many conversions of mangrovesinto cultivation ponds, as well as conversions into agricultural land such as paddy fields andpastures, accompanied by an increase in demand for oil palm which causes land clearing. Inaddition, the population around the coastal area is increasing, resulting in the clearing ofmangrove land for infrastructure development such as road and port construction. In order toreduce the rate of mangrove deforestation, it is necessary to conserve and restore mangroves.By preserving mangrove forests, not only maintain carbon stocks for climate change mitigationbut also facilitate adaptation to climate change such as sea level rise.

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Threats to terrestrial biodiversity

The Ecology of Tropical East Asia ◽

10.1093/oso/9780198817017.003.0007 ◽

2019 ◽

pp. 177-212

Author(s):

Richard T. Corlett

Keyword(s):

Climate Change ◽

Human Population ◽

Human Impacts ◽

Emerging Infectious Diseases ◽

Forest Products ◽

Wildlife Trade ◽

Infrastructure Development ◽

Non Timber Forest Products ◽

Negative Impacts ◽

Terrestrial Biodiversity

More than a billion people inhabit Tropical East Asia today and negative impacts on ecosystems and wild species are pervasive. Historically, the ultimate driver has been human population growth, but while this is now slowing, there is no prospect of an early reduction in human impacts. Poverty, corruption, weak governance, and globalization are additional underlying drivers. The major proximal threats and their consequences—deforestation, habitat fragmentation, mining, urbanization and infrastructure development, logging and the collection of non-timber forest products, hunting and the wildlife trade, fires, invasive species, emerging infectious diseases, air pollution and nutrient enrichment, and anthropogenic climate change—are described in turn in this chapter. Finally, the problems of assessing and predicting extinctions are discussed.

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Climate Change Impact, Adaptation, and Mitigation in Temperate Grazing Systems: A Review

Sustainability ◽

10.3390/su11247224 ◽

2019 ◽

Vol 11 (24) ◽

pp. 7224 ◽

Cited By ~ 5

Author(s):

Afshin Ghahramani ◽

S. Mark Howden ◽

Agustin del Prado ◽

Dean T. Thomas ◽

Andrew D. Moore ◽

...

Keyword(s):

Climate Change ◽

Climate Change Impact ◽

Agricultural Land ◽

Ghg Emissions ◽

Mitigation Strategies ◽

Mitigation Measures ◽

Temperate Grasslands ◽

Elevated Atmospheric Co2 ◽

Change Impact ◽

Adaptation And Mitigation

Managed temperate grasslands occupy 25% of the world, which is 70% of global agricultural land. These lands are an important source of food for the global population. This review paper examines the impacts of climate change on managed temperate grasslands and grassland-based livestock and effectiveness of adaptation and mitigation options and their interactions. The paper clarifies that moderately elevated atmospheric CO2 (eCO2) enhances photosynthesis, however it may be restiricted by variations in rainfall and temperature, shifts in plant’s growing seasons, and nutrient availability. Different responses of plant functional types and their photosynthetic pathways to the combined effects of climatic change may result in compositional changes in plant communities, while more research is required to clarify the specific responses. We have also considered how other interacting factors, such as a progressive nitrogen limitation (PNL) of soils under eCO2, may affect interactions of the animal and the environment and the associated production. In addition to observed and modelled declines in grasslands productivity, changes in forage quality are expected. The health and productivity of grassland-based livestock are expected to decline through direct and indirect effects from climate change. Livestock enterprises are also significant cause of increased global greenhouse gas (GHG) emissions (about 14.5%), so climate risk-management is partly to develop and apply effective mitigation measures. Overall, our finding indicates complex impact that will vary by region, with more negative than positive impacts. This means that both wins and losses for grassland managers can be expected in different circumstances, thus the analysis of climate change impact required with potential adaptations and mitigation strategies to be developed at local and regional levels.

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The Distributional Impact of Tax and Social Security Reforms in the UK from 2010 to 2017

Social Policy and Society ◽

10.1017/s1474746420000093 ◽

2020 ◽

Vol 19 (3) ◽

pp. 470-486 ◽

Cited By ~ 1

Author(s):

Howard Reed

Keyword(s):

Social Security ◽

Low Income ◽

Net Income ◽

Cumulative Impact ◽

Number Of Children ◽

Cumulative Impact Assessment ◽

Social Security Reforms ◽

Households With Children ◽

Negative Impacts ◽

The Uk

This article presents the results from a cumulative impact assessment of the distribution of tax and social security reforms in the UK since the 2010 general election. The analysis covers the 2010-15 and 2015-17 parliaments plus measures announced in the Autumn 2017 Budget. The article finds that taken as a whole, reforms since 2010 have had a regressive impact across the household income distribution, with average losses of around 10 per cent of net income in the bottom fifth of the distribution, compared to roughly a zero impact in the top three deciles. I also analyse results by a number of Equality Act protected characteristics including ethnicity, disability, gender, single/couple status and the number of children in the household. Lone parent families lose out more than any other demographic group while Pakistani and Bangladeshi adults lose out more than any other ethnic group. The reforms also have particular negative impacts on disabled people, on low income women and on households with children.

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Hydrological responses of a watershed to historical land use evolution and future land use scenarios under climate change conditions

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-4-1337-2007 ◽

2007 ◽

Vol 4 (3) ◽

pp. 1337-1367 ◽

Cited By ~ 4

Author(s):

R. Quilbé ◽

A. N. Rousseau ◽

J.-S. Moquet ◽

S. Savary ◽

S. Ricard ◽

...

Keyword(s):

Climate Change ◽

Land Use ◽

Agricultural Land ◽

Water Discharge ◽

Hydrological Responses ◽

Land Use Scenario ◽

Land Use Scenarios ◽

Key Factor ◽

Agriculture Intensification ◽

In The Beginning

Abstract. Watershed runoff is closely related to land use, but this influence is difficult to quantify. This study focused on the Chaudière River watershed (Québec, Canada) and had two objectives: (i) to quantify the influence of historical agricultural land use evolution on watershed runoff; and (ii) to assess the effect of future land use evolution scenarios under climate change conditions (CC). To achieve this, we used the integrated modeling system GIBSI. Past land use evolution was constructed using satellite images that were integrated into GIBSI. The general trend was an increase of agricultural land in the 1980s, a slight decrease in the beginning of the 1990s and a steady state over the last ten years. Simulations based on thirty years of daily meteorological series showed strong correlations between land use evolution and water discharge at the watershed outlet, especially for summer and fall seasons. For the prospective approach, we first assessed the effect of CC and then defined two opposite land use evolution scenarios for the horizon 2025 based on two different trends: agriculture intensification or sustainable development. Simulation results showed that CC would induce an increase of water discharge during winter and a decrease the rest of the year, while land use scenarios would have a more drastic effect, agriculture intensification counterbalancing the effect of CC during summer and fall. Due to the large uncertainty linked to CC simulations, it is difficult to conclude that one land use scenario provides a better adaptation to CC than another, but this study shows that land use is a key factor that has to be taken into account when predicting potential future hydrological responses of a watershed.

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River Discharge and Water Level Changes in the Mekong River: Droughts in an Era of Mega-Dams

10.22541/au.161189206.60684509/v1 ◽

2021 ◽

Author(s):

XiXi Lu ◽

Samuel Chua

Keyword(s):

Water Level ◽

Water Discharge ◽

Dry Season ◽

Water Levels ◽

Mekong River ◽

Wet Season ◽

Discharge Data ◽

Mekong Basin ◽

Lower Mekong Basin ◽

Dry Conditions

While 1992 marked the first major dam – Manwan – on the main stem of the Mekong River, the post-2010 era has seen the construction and operationalisation of mega dams such as Xiaowan (started operations in 2010) and Nuozhadu (started operations in 2014) that were much larger than any dams built before. The scale of these projects implies that their operations will likely have significant ecological and hydrological impacts from the Upper Mekong Basin to the Vietnamese Delta and beyond. Historical water level and water discharge data from 1960 to 2020 were analysed to examine the changes to streamflow conditions across three time periods: 1960-1991 (pre-dam), 1992-2009 (growth) and 2010-2020 (mega-dam). At Chiang Saen, the nearest station to the China border, monthly water discharge in the mega-dam period has increased by up to 98% during the dry season and decreased up as much as -35% during the wet season when compared to pre-dam records. Similarly, monthly water levels also rose by up to +1.16m during the dry season and dropped by up to -1.55m during the wet season. This pattern of hydrological alterations is observed further downstream to at least Stung Treng (Cambodia) in our study, showing that Mekong streamflow characteristics have shifted substantially in the post-2010 era. In light of such changes, the 2019-2020 drought – the most severe one in the recent history in the Lower Mekong Basin – was a consequent of constructed dams reducing the amount of water during the wet season. This reduction of water was exacerbated by the decreased monsoon precipitation in 2019. Concurrently, the untimely operationalisation of the newly opened Xayaburi dam in Laos coincided with the peak of the 2019-2020 drought and could have aggravated the dry conditions downstream. Thus, the mega-dam era (post-2010) may signal the start of a new normal of wet-season droughts.

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Climate Change and Sugarcane Production: Potential Impact and Mitigation Strategies

International Journal of Agronomy ◽

10.1155/2015/547386 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 45

Author(s):

Duli Zhao ◽

Yang-Rui Li

Keyword(s):

Climate Change ◽

Adaptive Capacity ◽

Greenhouse Gas Emission ◽

Geographic Location ◽

Saccharum Officinarum ◽

Mitigation Strategies ◽

Extreme Weather Events ◽

Sugarcane Production ◽

Weather Events ◽

Negative Impacts

Sugarcane (Saccharum officinarumL.) is an important crop for sugar and bioenergy worldwide. The increasing greenhouse gas emission and global warming during climate change result in the increased frequency and intensity of extreme weather events. Climate change is expected to have important consequences for sugarcane production in the world, especially in the developing countries because of relatively low adaptive capacity, high vulnerability to natural hazards, and poor forecasting systems and mitigating strategies. Sugarcane production may have been negatively affected and will continue to be considerably affected by increases in the frequency and intensity of extreme environmental conditions due to climate change. The degree of climate change impact on sugarcane is associated with geographic location and adaptive capacity. In this paper, we briefly reviewed sugarcane response to climate change events, sugarcane production in several different countries, and challenges for sugarcane production in climate change in order for us to better understand effects of climate change on sugarcane production and to propose strategies for mitigating the negative impacts of climate change and improving sugarcane production sustainability and profitability.

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Hydrological responses of a watershed to historical land use evolution and future land use scenarios under climate change conditions

Hydrology and Earth System Sciences ◽

10.5194/hess-12-101-2008 ◽

2008 ◽

Vol 12 (1) ◽

pp. 101-110 ◽

Cited By ~ 50

Author(s):

R. Quilbé ◽

A. N. Rousseau ◽

J.-S. Moquet ◽

S. Savary ◽

S. Ricard ◽

...

Keyword(s):

Climate Change ◽

Land Use ◽

Agricultural Land ◽

Water Discharge ◽

Low Flow ◽

Hydrological Responses ◽

Land Use Scenario ◽

Wide Range ◽

Land Use Scenarios ◽

Key Factor

Abstract. Watershed runoff is closely related to land use but this influence is difficult to quantify. This study focused on the Chaudière River watershed (Québec, Canada) and had two objectives: (i) to quantify the influence of historical agricultural land use evolution on watershed runoff; and (ii) to assess the effect of future land use evolution scenarios under climate change conditions (CC). To achieve this, we used the integrated modeling system GIBSI. Past land use evolution was constructed using satellite images that were integrated into GIBSI. The general trend was an increase of agricultural land in the 80's, a slight decrease in the beginning of the 90's and a steady state over the last ten years. Simulations showed strong correlations between land use evolution and water discharge at the watershed outlet. For the prospective approach, we first assessed the effect of CC and then defined two opposite land use evolution scenarios for the horizon 2025 based on two different trends: agriculture intensification and sustainable development. Simulations led to a wide range of results depending on the climatologic models and gas emission scenarios considered, varying from a decrease to an increase of annual and monthly water discharge. In this context, the two land use scenarios induced opposite effects on water discharge and low flow sequences, especially during the growing season. However, due to the large uncertainty linked to CC simulations, it is difficult to conclude that one land use scenario provides a better adaptation to CC than another. Nevertheless, this study shows that land use is a key factor that has to be taken into account when predicting potential future hydrological responses of a watershed.

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