Assessing Environmental Quality Dynamics and its Response to Vegetation Change in the Upper Minjiang River Watershed by Modis and Spot Products

Author(s):  
Enxu Yu ◽  
Mingfang Zhang ◽  
Yiping Hou ◽  
Zhiwei Jiang ◽  
Lihao Deng ◽  
...  
2018 ◽  
Vol 28 (55) ◽  
pp. 898-917
Author(s):  
Lucas Pereira Soares ◽  
Ernane Cortez Lima

O presente trabalho tem como objetivo apresentar uma caracterização climática e hidrológica das nascentes do alto curso do Rio Acaraú, localizado no Maciço Residual Serra das Matas, região centro-oeste do estado do Ceará, compreendendo uma área de 142,63Km2. Neste estudo, procurou-se contextualizar a área da pesquisa, através da análise dos atributos climáticos, tais como dinâmica e elementos do clima, sendo temperatura e precipitação, com ênfase no balanço hídrico e sua relação com os recursos hídricos disponíveis à área, sendo elaborado mapas e gráficos temáticos, caracterizando as informações climatológicas. A análise foi desenvolvida através do cruzamento das informações climáticas, e demais informações geoambientais, visando identificar as peculiaridades no que tange a tipologia climática semiárida, a fim de conceber as limitações e potencialidades dos recursos naturais dessa área, com destaque aos recursos hídricos. Finalmente, após a integração desses dados são apresentados resultados no que tange a tipologia semiárida, em integração aos recursos hídricos da região, com objetivo de subsidiar o desenvolvimento do Projeto de Revitalização das Nascentes do Rio Acaraú, desenvolvido pelo Comitê de Bacia Hidrográfica do Rio Acaraú, para que as medidas corretamente aplicadas possam contribuir para a preservação da qualidade ambiental no alto curso do Rio Acaraú-CE. Palavras–chave: balanço hídrico, recursos hídricos, semiárido.AbstractThe aim of this work is to present a climatic and hydrological characterization of the water springs of the upper course of the Acaraú River, located in the Residual Mass Serra das Matas, Central-West region of the state of Ceará, comprising an area of 142, 63Km2. In this study, we sought to contextualize the area of research, through the analysis of the climatic attributes, such as dynamics and elements of the climate, being temperature and rainfall, with emphasis on the hydric assessment and its relation with the hydric resources available to area, being elaborated maps and thematic charts, featuring the climatological information. The analysis was developed through the intersection of climate information, and other geoenvironmental information, aiming at identifying the peculiarities of the semi-arid climatic typology, in order to devise the limitations and potentialities of the resources Of this area, with emphasis on hydric resources. Finally, after the integration of these data are presented results with regard to the semi-arid typology, in integration with the region hydric resources , with the objective of subsidizing the development of the project of revitalization of the water springs of the Acaraú River, Developed by the Acaraú River Watershed Committee, so that properly applied measures can contribute to the preservation of environmental quality in the upper course of the Acaraú-CE River.Key words: hydric assessment, hydric resources, semi-arid.


Author(s):  
Jadson Rocha ◽  
Neylor Rego ◽  
José Santos ◽  
Raquel Maria Oliveira ◽  
Max Menezes

2012 ◽  
Vol 16 (11) ◽  
pp. 4279-4290 ◽  
Author(s):  
X. Cui ◽  
S. Liu ◽  
X. Wei

Abstract. Quantifying the effects of forest changes on hydrology in large watersheds is important for designing forest or land management and adaptation strategies for watershed ecosystem sustainability. Minjiang River watershed, located in the upper reach of the Yangtze River basin, plays a strategic role in the environmental protection and economic and social well-being for both the watershed and the entire Yangtze River basin. The watershed lies in the transition zone from Sichuan Basin to Qinghai-Tibet Plateau with a size of 24 000 km2. Due to its strategic significance, severe historic deforestation and high sensitivity to climate change, the watershed has long been recognized as one of the highest priority watersheds in China for scientific research and resource management. The purpose of this review paper is to provide a state-of-the-art summary on what we have learned from several recently completed research programs (one of them known as "973 of the China National Major Fundamental Science" from 2002 to 2008). This summary paper focused on how land cover or forest change affected hydrology at both forest stand and watershed scales in this large watershed. Inclusion of two different spatial scales is useful, because the results from a small spatial scale (e.g. forest stand level) can help interpret the findings on a large spatial scale. Our review suggests that historic forest harvesting or land cover change has caused significant water yield increase due to reduction of forest canopy interception and evapotranspiration caused by removal of forest vegetation on both spatial scales. The impact magnitude caused by forest harvesting indicates that the hydrological effects of forest or land cover changes can be as important as those caused by climate change, while the opposite impact directions suggest their offsetting effects on water yield in the Minjiang River watershed. In addition, different types of forests have different magnitudes of evapotranspiration (ET), with the lowest in old-growth natural coniferous forests (Abies faxoniana Rehd. et Wils.) and the highest in coniferous plantations (e.g. Picea asperata Mast.) among major forest types in the study watershed. This suggests that selection of different types of forests can have an important role in ET and consequently water yield. Our synthesis indicates that future reforestation and climate change would likely produce the hydrological effects in the same direction and thus place double the pressure on water resource as both key drivers may lead to water yield reduction. The findings can support designing management strategies for protection of watershed ecological functions in the context of future land cover and climate changes.


2021 ◽  
Author(s):  
Xin Jin ◽  
Yanxiang Jin

Abstract Vegetation change in arid areas may lead to the redistribution of regional water resources, which can intensify the competition between ecosystems and humans for water resources. Thus, it is necessary to understand the impact of vegetation change on hydrological processes in arid areas. We aimed to accurately model the impact of vegetation change on hydrological processes in an arid endorheic river watershed undergoing revegetation. The middle and lower reaches of the Bayin River basin, China were investigated because this is an area of frequent surface water–groundwater interactions and evident revegetation. A LU-SWAT-MODFLOW model was developed by integrating dynamic hydrological response units with a coupled SWAT-MODFLOW model, which can reflect actual land cover changes in the basin. The results showed that the LU-SWAT-MODFLOW model outperformed the original SWAT-MODFLOW model in simulating human activity impact as well as the leaf area index, evapotranspiration, and groundwater table depth. After regional revegetation, evapotranspiration in different sub-basins increased by 1.5 mm per month and by 6 mm per year. The groundwater recharge increased by 1.27 mm on average per month and 14.02 mm on average per year. Irrigation for the recovered vegetation strongly affected the groundwater recharge. In addition, the direction and amount of surface water–groundwater exchange considerably changed in areas where revegetation involved converting low-coverage grassland and bare land to forestland. In areas where revegetation involved converting farmland to forestland, the transition had a weak effect on the direction and amount of surface water–groundwater exchange.


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