检索结果-南通市图书馆

Comparison of water quality in two catchments with different forest types in the headwater region of the Hun River, Northeast China

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2019年第2期30卷 565-576页

作者： Jiao-jun Zhu Li-zhong Yu Tian-le Xu Xiaohua Wei Kai Yang CAS Key Laboratory of Forest Ecology and Management Institute of Applied Ecology Chinese Academy of Sciences Qingyuan Forest CERN Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Earth and Environmental Sciences University of British Columbia (Okanagan Campus)

In the headwater catchments of the Hun River,Northeast China, secondary forests(SF) have been replaced by plantations since the 1960 s. Concern has been growing over this loss and the decline in water quality caused by the plantations. To test the effects of plantations on water quality, we selected two separate catchments covered by SF and Pinus koraiensis plantations(KP) to monitor physical and chemical properties of various hydrological variables including throughfall, stemflow,through-litterfall and runoff(flowing out of outlets of the catchments). The physical properties of water declined after water flowed through the two catchments as compared with rainwater. The pH of runoff in both catchments also dramatically decreased. The concentrations of Cl^-, NO_3^- and NH_4^+ in the runoff from the two catchments were similar(concentrations of Cl-and NH_4^+ in both catchments were similar to those in rainwater). Total P concentration in runoff of the SF catchment was higher than that of the KP catchment(P concentrations in both catchments were also higher than in rainwater) because P concentrations in litter and soil of the SF catchment were higher than those in the KP catchment. In summary, the rainwater became acidic in both catchments, but the responses of most water quality variables were similar in the two catchments, suggesting that appropriate ratios of KP in SF are feasible for secondary forest recovery and for preserving water quality(KP did not cause a decline in quality) in the headstream regions in Northeast of China.

关键词： Forested catchments Secondary forests Plantations Water quality

Hydrological Processes of Storm Runoff from catchments of Different Land Uses

在线全文

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2007年第2期12卷 317-321页

作者： HONG Lin LI Minggang SONG Yuansheng State Key Laboratory of Water Resources and Hydropower Engineering Science/School of Water Resources and Hydropower Wuhan University Wuhan 430072 Hubei China

In this paper, a novel and efficient study on the hydrological processes of storm runoff from catchments of different land uses is conducted. The motivation is to precisely simulate the hydrological processes of storm runoff in the agricultural catchments with different patterns of land uses, i.e., forest, paddy, and upland, respectively. As it is discussed in this paper, different land use leads to different characteristics of storm runoff. In order to understand the changes in the hydrological processes of storm runoff from catchments of different land uses, the effects of rainfall intensity, initial soil moisture deficit, evapotranspiration rate, percolation rate, and retention capacity on hydrological processes of the catchments are taken into consideration. According to the principle of water balance, a general model to connect the separate hydrological processes is developed; then, the individual hydrological process is studied in detail： Firstly, the daily evaporation is calculated according to the relation between the actual evapotranspiration and the potential evapotranspiration rate; Secondly, the retention of storm runoff is plotted against the total rainfall, and the maximum storage is calculated; Thirdly, the percolation rate is calculated for each catchment.

关键词： storm runoff hydrological process catchments different land use

Episode Studies on catchments Chemistry at Tie Shan Ping,Chongqing

在线全文

学校读者我要写书评

暂无评论

工程科学（英文版） 2007年第3期5卷 42-50页

作者： Zhao Dawei(Chongqing Institute of Environmental Science and Monitoring,Chongqing 400020,China)

The Tie Shan Ping(TSP) catchments are acidified due to acid *** highest concentrations of SO2-4,NO-3,Ca2+,Mg2+ Al3+ and H+ occur in soil water and the maximum of molar ratio Ali/(Ca+Mg) during the Episode Studies is 1.27 in the bottom soil water in May *** Cluster Analysis for compartmental water chemistry in catchments shows stream water(SW) originates from the soil water *** event rain there may be 'pulse' of high concentration of chemical species in the *** organic carbon,organic bound aluminum,total phosphorus,total nitrogen,NO-3 in SW are controlled by quick(high) *** at new dam at TSP is from quick flow largely,including overland flow during wet ***3+,SO2-4 and H+ in SW are controlled by base flow during dry period and SW at old dam at TSP is from the base flow,*** are "alkaline pulse" and "acid pulse" in stream water during the event *** former may be caused by overland flow over the litterfall and topsoil horizons,and the latter by "piston flow" from soil water in deeper soil horizon largely.

关键词： air pollution acid deposition throughfall soil water catchments

Large Wood Volume and Longitudinal Distribution in Channel Segments Draining catchments with Different Land Use, Chile

在线全文

学校读者我要写书评

暂无评论

Open Journal of Modern Hydrology 2014年第2期4卷 57-66页

作者： A. Iroumé L. Mao H. Ulloa C. Ruz A. Andreoli Department of Ecosystems and Environments Pontificia Universidad Católica de Chile Santiago Chile Department of Forestry and Environmental Management Universidad de Concepción Concepción Chile Faculty of Engineering Sciences School of Civil Engineering Universidad Austral de Chile Valdivia Chile Faculty of Forest Sciences and Natural Resources Universidad Austral de Chile Graduate School Valdivia Chile Faculty of Forest Sciences and Natural Resources Universidad Austral de Chile Valdivia Chile

The storage, longitudinal distribution and recruitment processes of in-stream large wood (LW) were studied comparing channel segments draining four Chilean mountain catchments with different land use. The segments were divided into relatively uniform reaches of different lengths and surveyed for LW (piece dimensions, position in the channel, orientation to flow and aggregation) and stream morphology (slope and bank full channel width and depth) characterizations. LW volume stored in the Pichun, El Toro and Vuelta de Zorra study channels are within the range informed in international researches from streams draining catchments with similar forest covers. However, the 1057 m3/ha of LW stored in Tres Arroyos is extremely high and in the same order of magnitude than the reports from old-growth forests in the Pacific Northwest of USA. The size of the area that can potentially provide wood to streams depends on the wood supply mechanisms within any catchment, and the LW stored in the study segments increases as the size of this area increases. This study aims to contribute to the knowledge on the effects of LW in mountain channels, gathering new information and expanding investigations developed in Chile since 2008. This research was carried out within the framework of Project FONDECYT 11106209.

关键词： Large Wood Wood Storage LW Longitudinal Distribution Mountain catchments

Hydrological Controls on Nutrient Exportation from Old-Growth Evergreen Rainforests and <i>Eucalyptus nitens</i>Plantation in Headwater catchments at Southern Chile

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Modern Hydrology 2015年第2期5卷 19-31页

作者： Carlos E. Oyarzun Pedro Hervé-Fernández Dries Huygens Pascal Boeckx Niko E. C. Verhoest Instituto de Ciencias Ambientales y Evolutivas Facultad de Ciencias Universidad Austral de Chile Valdivia Chile Laboratory of Hydrology and Water Management Faculty Bioscience Engineering Ghent University Ghent Belgium Isotope Bioscience Laboratory (ISOFYS) Ghent University Ghent Belgium Institute of Agricultural Engineering and Soil Science Faculty of Agricultural Sciences Universidad Austral de Chile Valdivia Chile Instituto Multidisciplinario de Biología Vegetal (IMBIV) Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina Facultad de Ciencias Exactas Físicas y Naturales Universidad Nacional de Córdoba Córdoba Argentina

Soil cover disturbances have a direct effect on biogeochemistry, potentially enhancing nutrient loss, land degradation and associated changes in ecosystem services and livelihood support. The objective of this study was to assess how canopy affected throughfall chemistry and how hydrology affected stream nutrient load responses in two watersheds dominated by native old-growth evergreen rainforest (NF) and exotic plantation of Eucalyptus nitens (EP), located at the Coastal mountain range of southern Chile (40°S). We measured nitrogen (NO3-N, NH4-N, Organic-N, Total-N) and total phosphorus (Total-P) at catchment discharge, and δ18O in throughfall precipitation and stream discharge in both catchments, in order to separate throughfall (or new water) contributions during storm events. It was hypothesized that all nutrients showed an increase in concentration as discharge increased (or enhanced hydrological access), in EP;but not in NF. Our results indicated that Organic-N, Total-N and Total-P concentrations were positively related to discharge. However, NO3--N showed a negative correlation with catchment discharge. Organic-N and Total-P showed a flush during storm events;the opposite was observed for NO3--N. However, this behavior suggested that NO3--N was being retained by charged particles or soil micro biota, whether Organic-N was flushed as it was more concentrated in big pore water that was not tightly attached, compared with NO3--N.

关键词： Native Rainforests Exotic Plantations Nutrient Fluxes Hydrological Controls Headwater catchments

Assessing sediment connectivity and its spatial response on land use using two flow direction algorithms in the catchment on the Chinese Loess Plateau

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2022年第4期19卷 1119-1138页

作者： YAN Xi-qin JIAO Ju-ying TANG Bing-zhe LIANG Yue WANG Zhi-jie State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationChinese Academy of Sciences and Ministry of Water ResourcesYangling 712100China Institute of Soil and Water Conservation Northwest A&F UniversityYangling 712100China University of Chinese Academy of Sciences Beijing 100049China College of Life Sciences Guizhou UniversityGuiyang 550025China

Severe soil and water loss have led to widespread land degradation on the Loess Plateau in *** the relationship between land use and sediment connectivity can be beneficial to control soil *** this study,three catchments in the Yanhe River Basin on the Loess Plateau were selected to analyse the relationship between land use and sediment connectivity using grey correlation *** of connectivity(IC)was employed to quantify sediment connectivity,including two flow direction algorithms(D8 and D-infinity)and two final targets of sediment transport(outlet and main channel of catchment).Then,11 landscape metrics were used to evaluate the land use spatial patterns of *** comparing the IC value ranges,histograms and classes,and their relationship with remote sensing images of the two flow direction algorithms,we find that the D8 algorithm is more suitable for this study *** results showed that the three catchments are characterized by high sediment connectivity in the grassland and forest close to the *** addition,the roads and bare land close to the channel also have high or medium sediment *** correlation analysis showed that landscape division index(DIVISION),fractal dimension index(FRACMN),aggregation index(AI),total class area,patch cohesion index(COHESION),and largest patch index(LPI)indices were the main factors that affect sediment connectivity at the class *** the landscape scale,the landscape shape index(LSI),Shannon’s diversity index(SHDI),and gully density have an essential effect on sediment *** condition provides a way to control the sediment connectivity in the watershed by transforming land use type or changing its spatial pattern,but specific adjustment measures have to be further explored.

关键词： Sediment connectivity Land use Landscape metrics catchments Loess Plateau

Zonal aspects of the influence of forest cover change on runoff in northern river basins of Central Siberia

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2021年第3期8卷 602-614页

作者： A.Onuchin Т.Burenina А.Shvidenko D.Prysov A.Musokhranova V.N.Sukachev Institute of Forest Siberian Branch of the Russian Academy of Sciences 660036Academgorodok50/28Russia 31KrasnoyarskRussia International Institute for Applied Systems Analysis A-2361 LaxenburgAustria

Background:Assessment of the reasons for the ambiguous influence of forests on the structure of the water balance is the subject of heated debate among forest *** the components of total evaporation,forest vegetation makes a significant contribution to the process of runoff formation,but this process has specific features in different geographical *** issues of the influence of forest vegetation on river runoff in the zonal aspect have not been sufficiently ***:Based on the analysis of the dependence of river runoff on forest cover,using the example of nine catchments located in the forest-tundra,northern and middle taiga of Northern Eurasia,it is shown that the share of forest cover in the total catchment area(percentage of forest cover,FCP)has different effects on runoff *** experiments with the developed empirical models have shown that an increase in forest cover in the catchment area in northern latitudes contributes to an increase in runoff,while in the southern direction(in the middle taiga)extensive woody cover of catchments“works”to reduce *** effectiveness of geographical zonality in regards to the influence of forests on runoff is more pronounced in the forest-tundra zone than in the zones of northern and middle ***:The study of this problem allowed us to analyze various aspects of the hydrological role of forests,and to show that forest ecosystems,depending on environmental conditions and the spatial distribution of forest cover,can transform water regimes in different *** the fact that the process of river runoff formation is controlled by many factors,such as temperature conditions,precipitation regime,geomorphology and the presence of permafrost,the models obtained allow us to reveal general trends in the dependence of the annual river runoff on the percentage of forest cover,at the level of *** results obtained are consistent with the concept of geographic

关键词： River runoff catchments Forest cover Geographic zoning Central Siberia

Calibration of a Rainfall-Runoff Model to Estimate Monthly Stream Flow in an Ungauged Catchment

在线全文

学校读者我要写书评

暂无评论

Computational Water, Energy, and Environmental Engineering 2015年第4期4卷 57-66页

作者： Shahrbanou Firouzi Mohamad B. Sharifi Synthesis and Balance Department Northern Khorasan Regional Water Authority Bojnord Iran Faculty of Civil Engineering Ferdowsi University of Mashhad Mashhad Iran

Simulation of runoff in ungauged catchments has always been a challenging issue, receiving significant attention more importantly in practical applications. This study aims at calibration of an Artificial Neural Network (ANN) model which is capable to apply in an ungauged basin. The methodology is applied to two sub-catchments located in the Northern East of Iran. To examine the effect of physical characteristics of the catchment on the capability of the model generalization, it is attempted to synthesize effective parameters using empirical methods of runoff estimation. Firstly, the model was designed for a pilot sub-catchment and the statistical comparison between simulated runoff, and target depicted the capability of ANN to accurately estimate runoff over a catchment. Then, the calibrated model was generalized to another sub-catchment assumed as an ungauged basin while there are runoff data to compare the result. The result showed that the designed model is relatively capable to estimate monthly runoff for a homogenous ungauged catchment. The method presented in this study in addition to adding effective spatial parameters in simulation runoff and calibration of model by using empirical methods and the integration of any useful accessible data, examines the adaptability of model to an ungauged catchment.

关键词： Artificial Neural Network (ANN) Ungauged catchments Spatial Parameters