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1.
J Environ Manage ; 278(Pt 1): 111524, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33126187

RESUMO

Human-induced changes in land and water resources adversely affect global hydrological regimes. Hydrological alteration of the natural flow regime is considered to have a significant damaging and widespread impact on river ecosystems and livelihoods. Therefore, understanding the hydrological alteration of rivers and the potential driving factors affecting such alterations are crucial to effective water resources management. This study analyses the impact of changes in land use, climate, and hydropower development on the hydrological regime of the Srepok River Basin in the Lower Mekong Region. The Lower Mekong Basin (LMB) in Southeast Asia is known for its agriculture, forests, fisheries, wildlife, and diverse natural ecosystems. Historical land use and climate change are quantified (utilising European Space Agency land cover and observed meteorological data) and correlated with the hydrological indicators using the Indicators of Hydrologic Alteration (IHA) software. Moreover, pre and post impacts on the hydrological regime by hydropower development are quantified using the Range of Variability Approach (RAV) in IHA software. The results reveal that land use, rainfall, and temperature affect different aspects of the hydrological regime, with corroborating evidence to support variation among the most correlated IHA and environmental flow component (EFC) parameters with the three drivers. The highest and lowest correlations among the IHA and EFC parameters under each driver are against land use (0.85, -0.83), rainfall (0.78, -0.54), and minimum and max temperatures (0.42, -0.47). Among the parameters, the fall rate has the most significant effect on hydrological alteration of all drivers. Hydropower development in the basin mostly affects the fall rate and reversal. Identifying the connection between these multiple drivers and hydrological alteration could help decision-makers to design more efficient and sustainable water management policies.


Assuntos
Ecossistema , Rios , Ásia Sudeste , Hidrologia , Movimentos da Água
2.
Environ Res ; 186: 109544, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32361258

RESUMO

Among many factors the hydrology of a watershed is mainly influenced by climate and land use change. This study examined the impacts of climate change on water resources and extreme events in the Bang Pakong-Prachin Buri River Basin, Thailand using three different Regional Climate Models (RCMs) ACCESS1-CSIRO-CCAM, CNRM-CM5-CSIRO-CCAM, and MPI-ESM-LR-CSIRO-CCAM under RCP4.5 and RCP8.5 emission scenarios. Soil and Water Assessment Tool (SWAT) was used to simulate the future streamflow and Extreme Value Type I distribution (EVI) was used to analyze the extreme events under projected climate conditions. The result of this study showed an increase in maximum (1.9 °C/3.6 °C) and minimum (1.6 °C/3.3 °C) temperatures under RCP4.5/8.5 at the end of the 21st century. In addition, projected rainfall is expected to decrease up to 6.8% (8.5%) in 2050s and then increase slowly such that the decrement remains 4.2% (11.0%) under RCP4.5 (RCP8.5) at the end of the century. The rainfall pattern is projected to considerably fluctuate, in particular, a shift in long term average annual peak event from September to August is predicted in 2080s under emission scenario RCP4.5 (RCP8.5). On the other hand, the average annual discharge is expected to increase up to 13.5% (2020s) and 7.6% (2050s) under RCP4.5 and RCP8.5 respectively with decreasing trend in low flows and increasing trend in high flows. Further analysis on extreme events; strengthened the results from hydrological modeling with an increase in flow volume for the same return period under changed climate conditions. This raises water resources management issues in the Bang Pakong-Prachin Buri River Basin regarding the frequency of flood and drought events in the future calling for proper policy formulation and implementation.


Assuntos
Hidrologia , Rios , Mudança Climática , Inundações , Tailândia
3.
Environ Res ; 185: 109440, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32247909

RESUMO

Ho Chi Minh City (HCMC), Vietnam has undergone tremendous transformation in land-use practices in the past few decades. The groundwater-related issues have also been a major concern in the fast-growing southern city of Vietnam. Quantitative prediction of the impact on groundwater recharge due to changes in the land-use pattern of a watershed is crucial in developing sound groundwater management schemes. This study aims to evaluate the impacts of change in land-use patterns on the quantity of groundwater recharge in HCMC. An empirical land-use projection model (Conversion of Land-use and its Effects, Dyna-CLUE) and a hydrological model (Soil and Water Assessment Tool, SWAT) was used for the study. Three future land-use scenarios of Low Urbanization Scenario (LU), Medium Urbanization Scenario (MU) and High Urbanization Scenario (HU) were developed in Dyna-CLUE focusing on the increase of built-up area to generate land-use maps of HCMC until the year 2100. The land-use maps for all three scenarios were then used in the calibrated hydrological model SWAT to get the future recharge in the near future (2016-2045), mid future (2046-2075) and far future (2076-2100). The recharge was observed to increase in the far future of LU by 10% while reduction of 30% and 52% in annual average recharge was observed in far future of MU and HU respectively. It was, thus, observed that change in built-up area has a significant effect on the groundwater recharge in HCMC.


Assuntos
Água Subterrânea , Cidades , Hidrologia , Urbanização , Vietnã
4.
Environ Res ; 183: 109149, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32000001

RESUMO

Groundwater resources of Kathmandu Valley in Nepal are under immense pressure from multiple stresses, including climate change. Due to over-extraction, groundwater resources are depleting, leading to social, environmental and economic problems. Climate change might add additional pressure by altering groundwater recharge rates and availability of groundwater. Mapping groundwater resilience to climate change can aid in understanding the dynamics of groundwater systems, facilitating the development of strategies for sustainable groundwater management. Therefore, this study aims to analyse the impact of climate change on groundwater resources and mapping the groundwater resiliency of Kathmandu Valley under different climate change scenarios. The future climate projected using the climate data of RCM's namely ACCESS-CSIRO-CCAM, CNRM-CM5-CSIRO-CCAM and MPI-ESM-LR-CSIRO-CCAM for three future periods: near future (2010-2039), mid future (2040-2069) and far future (2070-2099) under RCP 4.5 and RCP 8.5 scenarios were bias corrected and fed into the Soil and Water Assessment Tool (SWAT), a hydrological model, to estimate future groundwater recharge. The results showed a decrease in groundwater recharge in future ranging from 3.3 to 50.7 mm/yr under RCP 4.5 and 19-102.1 mm/yr under RCP 8.5 scenario. The GMS-MODFLOW model was employed to estimate the future groundwater level of Kathmandu Valley. The model revealed that the groundwater level is expected to decrease in future. Based on the results, a groundwater resiliency map of Kathmandu Valley was developed. The results suggest that groundwater in the northern and southern area of the valley are highly resilient to climate change compared to the central area. The results will be very useful in the formulation and implementation of adaptation strategies to offset the negative impacts of climate change on the groundwater resources of Kathmandu Valley.


Assuntos
Mudança Climática , Água Subterrânea , Monitoramento Ambiental , Hidrologia , Nepal
5.
Diabet Med ; 37(5): 885-892, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31691356

RESUMO

AIM: India contributes towards a large part of the worldwide epidemic of diabetes and its associated complications. However, there are limited longitudinal studies available in India to understand the occurrence of diabetes complications over time. This pan-India longitudinal study was initiated to assess the real-world outcomes of diabetes across the country. METHODS: The LANDMARC study is the first prospective, multicentre, longitudinal, observational study investigating a large cohort of people with type 2 diabetes mellitus across India over a period of 3 years. The primary objective of this ongoing study is to determine the proportion of people developing macrovascular diabetes complications over the duration of the study (36 months ± 45 days) distributed over seven visits; the secondary objective is to evaluate microvascular diabetes complications, glycaemic control and time-to-treatment adaptation or intensification. Overall, 6300 participants (aged 25-60 years) diagnosed with type 2 diabetes for at least 2 years will be included from 450 centres across India. Data will be recorded for baseline demographics, comorbidities, glycaemic measurements, use of anti-hyperglycaemic medications and any cardiovascular or other diabetes-related events occurring during the observational study period. CONCLUSIONS: The LANDMARC study is expected to reveal the trends in complications associated with diabetes, treatment strategies used by physicians, and correlation among treatment, control and complications of diabetes within the Indian context. The findings of this study will help to identify the disease burden, emergence of early-onset complications and dose titration patterns, and eventually develop person-centred care and facilitate public health agencies to invest appropriate resources in the management of diabetes. (Trial Registration No: CTRI/2017/05/008452).

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