Analyzing the Impacts of Urbanization on Watershed Streamflow Characteristics

2020 ◽  
Author(s):  
Qining Shen ◽  
Zhentao Cong
Keyword(s):  
Growth Rate ◽  
San Antonio ◽  
Urban Expansion ◽  
High Flow ◽  
Rate Of Change ◽  
Metropolitan Region ◽  
Low Flow ◽  
Flow Volume ◽  
Discharge Data ◽  
Flow Frequency

<p>It is widely recognized that urbanization has a significant impact on streamflow characteristics. However, the influences of economic development, increasing population and positioning of urban development on streamflow regimes is still not fully understood. This study aims to clarify these influences by analyzing 134 catchments in China and 1064 catchments in the United State. Urbanization metrics were derived from gridded GDP dataset, gridded population dataset and land use/land cover datasets, while the streamflow characteristics were calculated using annual streamflow and mean daily discharge data. The statistical analysis indicated that the rate of change in rainfall-runoff ratio is positively related to the growth rate of GDP and urban area both in China and the U.S., but this relationship was not found in population growth rate. Increasing the extent of urbanized area increased high and low flow frequency in Kansas metropolitan region as well as San Antonio metropolitan region, while reduced low flow frequency in Atlanta metropolitan region. In addition, urban expansion also enhanced streamflow flashiness. Compared to down-stream development, up-stream development increased high flow volume in Atlanta metropolitan region and Kansas metropolitan region, while decreased high flow volume in San Antonio metropolitan region and low flow volume in all study metropolitan regions. The findings in this study provide a sight for future researches in hydrological variation due to urbanization.</p>

The Role of Intravascular Embolization Prior to Radiosurgery of Cerebral Arteriovenous Malformations

1999 ◽  
Vol 5 (1_suppl) ◽  
pp. 171-176 ◽  
Author(s):  
H.K. Inoue ◽  
Y. Nagaseki ◽  
I. Naitou ◽  
M. Negishi ◽  
M. Hirato ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Gamma Knife Radiosurgery ◽  
Latency Period ◽  
High Flow ◽  
Low Flow ◽  
Flow Volume ◽  
Cerebral Arteriovenous Malformations ◽  
Venous Obstruction ◽  
Risk Of Hemorrhage

The role of intravascular embolization prior to radiosurgery of cerebral arteriovenous malformations was evaluated based on the basis of the results of gamma knife radiosurgery in relation to hemorrhage and early obliteration after treatment. Nine of 213 patients experienced hemorrhage 4 to 42 months after radiosurgery. All AVMs in these patients had dilated feeding arteries, and the flow of the AVM was rapid and/or high. An intranidal aneurysm was seen in one patient. Drainage of all AVMs consisted of a single and/or deep draining veins, and venous obstruction was found in six. Sixty-three of 87 patients followed for more than four years after radiosurgery were examined angiographically, and total obliteration of AVM was observed in 52 of them (82.5%). Early obliteration was found in 19 of the 34 patients examined within 12 months. The obliteration rate was significantly higher in slow- and low-flow AVMs (73.9%) than in rapid- and/or high-flow AVMs (18.2%). It is concluded that the role of intravascular embolization prior to radiosurgery is not only decreasing the size of the AVM but decreasing the risk of hemorrhage and shortening the latency period by decreasing their flow rate and flow volume.

scholarly journals HYDROLOGICAL ASPECT OF BATANG ALAI WEIR WATERSHED DUE TO LAND USE CHANGES INTO MINING AREAS

CERUCUK ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 61
Author(s):  
Achmad Surian Nur ◽  
M. Azhari Noor
Keyword(s):  
Land Use ◽  
Hydrological Modeling ◽  
Mining Area ◽  
High Flow ◽  
Low Flow ◽  
Coefficient Of Determination ◽  
Design Flood ◽  
Discharge Data ◽  
Flood Discharge ◽  
Daily Discharge

The policy of the Ministry of Energy and Mineral Resources that provides permits for mining production activities for PT. MCM in the Batang Alai River area has an impact on the hydrology of the area. This study will discuss the changes in land use in the Batang Alai River area, Batang Alai Timur District, Hulu Sungai Tengah to the aspects of high flow and low flow hydrology.          The research method used is manual calculation with rational methods for high flow hydrology and calculations using the ArcSWAT 2012.10.1.18 for low flow hydrology. The data needed in the processing are rainfall data, DEM data, daily discharge data, climatology data, land use data, land use change data, and Batang Alai watershed data.          The results of the study were that the ratio of peak discharge of land use was changed to the mining area and land use was not converted into a mining area for high flow hydrology calculations. There is an increase in plan flood discharge in the Batang Alai River if there is a change in land use into a mining area, the design flood discharge always increases in each period. Whereas for low flow hydrology is the comparison between the daily use of land use converted into a mining area and land use is not converted into a mining area, then the daily discharge results are calculated for the availability of water. The results of low-flow hydrological modeling are categorized as good and have high influence based on the Nash-Sutcliffe efficiency value grouping and the coefficient of determination, and water availability decreases if land use is converted into a mining area.

scholarly journals Features of high flow access in the elderly

2019 ◽  
Vol 20 (1_suppl) ◽  
pp. 71-75
Author(s):  
Taro Kanno ◽  
Yutaka Kanno ◽  
Kazunari Shiroi ◽  
Nobuhiko Kobayashi ◽  
Natsumi Matsushita ◽  
...  
Keyword(s):  
Blood Flow ◽  
Elderly Patients ◽  
Young Patients ◽  
The Elderly ◽  
High Flow ◽  
Low Flow ◽  
Flow Volume ◽  
Middle Aged ◽  
Run Off ◽  
Elderly Hemodialysis Patients

Introduction: The number of elderly hemodialysis patients continues to grow. The aim of this study was to investigate differences in elderly high flow access patients compared with middle-aged and young patients. Methods: We performed a retrospective study to determine the characteristics of elderly patients (aged >60 years) following blood flow suppression procedures. Preoperative and postoperative data from 177 patients who underwent blood flow suppression procedures and 73 patients who underwent procedures for run-off vein ligation and subcutaneous fixation of the superficial artery were compared. Results: A high proportion of young (aged 20–40 years) and middle-aged (aged 41–60 years) patients met the criteria for blood flow suppression procedures (flow volume 1500 mL/min, flow volume/cardiac output 35%), whereas a high proportion of elderly patients did not. Moreover, heart strain could evidently be caused even with low flow volume. In elderly patients, a tricuspid regurgitation pressure gradient and right heart strain were observed more frequently. Conclusion: Elderly patients who underwent blood flow suppression procedures or subcutaneous fixation of the superficial artery exhibited lower flow volume, and the effects of high flow access in elderly patients depend on the nature of vascular changes. Ultimately, the underlying conditions and hemodynamics of each patient must be determined on an individual basis.

scholarly journals Effects of land use change on discharge of the Paraíba do Sul river

2021 ◽  
Vol 42 ◽  
pp. e53
Author(s):  
Caluan Rodrigues Capozzoli ◽  
Andrea De Oliveira Cardoso
Keyword(s):  
Land Use ◽  
Water Availability ◽  
Forest Cover ◽  
High Flow ◽  
Metropolitan Region ◽  
Low Flow ◽  
Annual Maximum ◽  
Daily Streamflow ◽  
Very High ◽  
Paraíba Do Sul River

The Paraíba do Sul river basin is located in the southeast region of Brazil and across São Paulo, Rio de Janeiro and Minas Gerais states. In addition to the urban and rural population in the basin, Paraíba do Sul River supplies about twelve million people in the Metropolitan Region of Rio de Janeiro, the third-largest metropolitan region in South America. Land-use in the basin is predominantly dairy farming, where inadequate soil management has affected the quality and quantity of water in the basin. In this work, a distributed hydrological model was performed to assess different surface coverage scenarios considering increments of forest cover along to the basin watercourses. The scenarios were compared with the current condition of the basin in terms of annual mean streamflow, annual maximum daily streamflow, and frequency of occurrence of very high and very low flow extremes. The simulations indicate a reduction in the annual mean streamflow rate due to the increase of the cover forest; reduction of annual maximum daily streamflow due to the increase in forest cover. Extreme frequency analysis indicates that increasing forest cover promotes a decrease in very high flow events and an increase in very low flow events during the rainy months of the basin (October to March), however, in the dry months (especially in August) the occurrence of very high flow events increases while very low flow events decrease. These results indicate that although on average and during the rainy season forest cover negatively affects surface water availability in the driest months, when water resources are scarcer, increased forest cover is beneficial for water availability in the basin.

scholarly journals Soil microbial inoculation during flood events shapes headwater stream microbial communities and diversity

2021 ◽  
Author(s):  
Florian Caillon ◽  
Katharina Besemer ◽  
Peter Peduzzi ◽  
Jakob Schelker
Keyword(s):  
Microbial Diversity ◽  
Bacterial Diversity ◽  
Soil Water ◽  
Headwater Streams ◽  
High Flow ◽  
Low Flow ◽  
Flood Events ◽  
Flow Conditions ◽  
Soil Microbial ◽  
Microbial Inoculation

AbstractFlood events are now recognized as potentially important occasions for the transfer of soil microbes to stream ecosystems. Yet, little is known about these “dynamic pulses of microbial life” for stream bacterial community composition (BCC) and diversity. In this study, we explored the potential alteration of stream BCC by soil inoculation during high flow events in six pre-alpine first order streams and the larger Oberer Seebach. During 1 year, we compared variations of BCC in soil water, stream water and in benthic biofilms at different flow conditions (low to intermediate flows versus high flow). Bacterial diversity was lowest in biofilms, followed by soils and highest in headwater streams and the Oberer Seebach. In headwater streams, bacterial diversity was significantly higher during high flow, as compared to low flow (Shannon diversity: 7.6 versus 7.9 at low versus high flow, respectively, p < 0.001). Approximately 70% of the bacterial operational taxonomic units (OTUs) from streams and stream biofilms were the same as in soil water, while in the latter one third of the OTUs were specific to high flow conditions. These soil high-flow OTUs were also found in streams and biofilms at other times of the year. These results demonstrate the relevance of floods in generating short and reoccurring inoculation events for flowing waters. Moreover, they show that soil microbial inoculation during high flow enhances microbial diversity and shapes fluvial BCC even during low flow. Hence, soil microbial inoculation during floods could act as a previously overlooked driver of microbial diversity in headwater streams.

Corrosion Rate Measurement by Hydrogen Effusion In Dynamic Aqueous Systems At Elevated Temperature and Pressure

CORROSION ◽  
1959 ◽  
Vol 15 (4) ◽  
pp. 29-32
Author(s):  
M. KRULFELD ◽  
M. C. BLOOM ◽  
R. E. SEEBOLD
Keyword(s):  
Elevated Temperature ◽  
Corrosion Rate ◽  
Flow Velocity ◽  
High Flow ◽  
Low Flow ◽  
Aqueous Systems ◽  
Effusion Rates ◽  
Temperature And Pressure ◽  
Effusion Method ◽  
Hydrogen Effusion

Abstract A method of applying the hydrogen effusion method to the measurement of corrosion rates in dynamic aqueous systems at elevated temperature and pressure is described. Data obtained in low carbon steel systems are presented, including (1) reproducibility obtained in measured hydrogen effusion rates at a flow velocity of 1 foot per second at a temperature of 600 F and 2000 psi, and (2) a quantitative comparison between the hydrogen effusion rates in static and in low flow velocity dynamic systems at this temperature and pressure. Some observations are included on corrosion rate measurements in a high flow velocity (30 feet per second) loop by the hydrogen effusion method. Implications of these measurements with regard to the comparison between high flow velocity corrosion and low flow velocity corrosion are mentioned and some data indicating high local sensitivity of the hydrogen effusion method are noted. Some possible difficulties involved in the method are pointed out. 2.3.4

Sign in / Sign up

Export Citation Format

Share Document