scholarly journals A modeling study of heterogeneity and surface water-groundwater interactions in the Thomas Brook catchment, Annapolis Valley (Nova Scotia, Canada)

2009 ◽  
Vol 6 (2) ◽  
pp. 2751-2793 ◽  
Author(s):  
M. J. Gauthier ◽  
M. Camporese ◽  
C. Rivard ◽  
C. Paniconi ◽  
M. Larocque
Keyword(s):  
Surface Water ◽  
Snow Accumulation ◽  
Return Flow ◽  
Eastern Canada ◽  
Groundwater Levels ◽  
The North ◽  
Spatio Temporal ◽  
Geological Complexity ◽  
Annapolis Valley ◽  
Response Variables

Abstract. A modelling study of the impacts of subsurface heterogeneity on the hydrologic response of an 8 km2 catchment in the Annapolis Valley (Eastern Canada) is reported. The study is focused in particular on the hydraulic connection and interactions between surface water and groundwater. A coupled (1-D surface/3-D subsurface) numerical model is used to investigate, for a range of scenarios, the spatio-temporal patterns of response variables such as return flow, recharge, groundwater levels, surface saturation, and streamflow. Eight scenarios of increasing geological complexity are simulated, introducing at each step more realistic representations of the geological strata and corresponding hydraulic properties. In a ninth scenario the effects of snow accumulation and snowmelt are also considered. The results show that response variables and significant features of the catchment (e.g., springs) can be adequately reproduced using a representation of the geology and model parameter values that are based on targeted fieldwork and existing databases, and that reflect to a sufficient degree the geological and hydrological complexity of the study area. The hydraulic conductivity values of the thin surficial sediment cover (especially till) and of the North Mountain basalts emerge as key elements of the basin's heterogeneity for properly capturing the overall catchment response.

scholarly journals A modeling study of heterogeneity and surface water-groundwater interactions in the Thomas Brook catchment, Annapolis Valley (Nova Scotia, Canada)

2009 ◽  
Vol 13 (9) ◽  
pp. 1583-1596 ◽  
Author(s):  
M. J. Gauthier ◽  
M. Camporese ◽  
C. Rivard ◽  
C. Paniconi ◽  
M. Larocque
Keyword(s):  
Surface Water ◽  
Snow Accumulation ◽  
Return Flow ◽  
Eastern Canada ◽  
Small Catchment ◽  
Groundwater Levels ◽  
Spatio Temporal ◽  
Geological Complexity ◽  
Annapolis Valley ◽  
Response Variables

Abstract. A modelling study of the impacts of subsurface heterogeneity on the hydrologic response of a small catchment is reported. The study is focused in particular on the hydraulic connection and interactions between surface water and groundwater. A coupled (1-D surface/3-D subsurface) numerical model is used to investigate, for a range of scenarios, the spatio-temporal patterns of response variables such as return flow, recharge, groundwater levels, surface saturation, and streamflow. Eight scenarios of increasing geological complexity are simulated for an 8 km2 catchment in the Annapolis Valley (eastern Canada), introducing at each step more realistic representations of the geological strata and corresponding hydraulic properties. In a ninth scenario the effects of snow accumulation and snowmelt are also considered. The results show that response variables and significant features of the catchment (e.g. springs) can be adequately reproduced using a representation of the geology and model parameter values that are based on targeted fieldwork and existing databases, and that reflect to a sufficient degree the geological and hydrological complexity of the study area. The hydraulic conductivity values of the thin surficial sediment cover (especially till) and of the basalts in the upstream reaches emerge as key elements of the basin's heterogeneity for properly capturing the overall catchment response.

Isotopic Characterization of groundwater in semi-arid Western India: Insights into Hydrogeological Processes

2021 ◽  
Author(s):  
Amit Pandey ◽  
Virendra Padhya ◽  
Rajendrakumar Dattatraya Deshpande
Keyword(s):  
Surface Water ◽  
Anthropogenic Sources ◽  
Return Flow ◽  
Western India ◽  
Clear Understanding ◽  
Post Monsoon ◽  
Recharge Sources ◽  
Isotopic Characterization ◽  
Spatio Temporal ◽  
Semi Arid

<p>The study area located in the semi-arid western India is the tenth most populous Indian state with an estimated population of 60.3 million (~5% of Indian population) and population density of 308 persons/km<sup>2</sup>. About 42.6% of the population lives in the urban area and 57.4% in rural areas.<strong> </strong>Surface water paucity, seasonal availability and a varying amount of rainfall in this region make groundwater an important and most preferred source to fulfil the demand for drinking water, agricultural, industrial and sustain an important native terrestrial ecosystem. The over-dependency on groundwater leads to various problems related to quality and quantity of groundwater like a rapid decline of the water table, mining of static groundwater, seawater intrusion and groundwater contamination by geogenic and anthropogenic sources. Sustainable water management across the state must be underpinned by the clear understanding of groundwater recharge characteristics, relationship between recharge sources and groundwater, factors controlling the interaction between surface water and groundwater, deletion of the areas not receiving a freshwater influx. Shallow groundwater samples were collected during IWIN nation programme (2008 to 2013)  for the year 2009 to measure the stable isotopes of oxygen and hydrogen in groundwater from 205 locations during post-monsoon (November ) season and 207 locations in pre-monsoon season ( May-June) to understand the factors governing Spatio-temporal variation in isotopic composition and obtain insights about the spatially variable recharge characteristics and possible controlling factors. The oxygen and hydrogen isotopic values and their spatio-temporal variations in the study area demonstrate that (1) d<sup>18</sup>O depletion in post-monsoon GW compare to pre-monsoon infer the seasonal recharge of GW (2) d<sup>18</sup>O of post-monsoon GW ( -2.3‰) lie in between the d<sup>18</sup>O of pre-monsoon GW ( -1.9‰) and d<sup>18</sup>O of southwest monsoon rainfall (-4.1‰) indicates post-monsoon GW is the mixture of these two components (3) Seasonal variation in d<sup>18</sup>O deduce that 56% ( ~109773 km2) of the total land area (~ 196773 km2) shows seasonal GW recharge while 32% (62727 km2) is not receiving any freshwater influx (4) 36% of post-monsoon samples while 40% of the pre-monsoon samples have negative d-excess values and shows a decreasing trend with d<sup>18</sup>O infer evaporation of sub-surface water prior to recharge (5) Alluvial aquifer of north Gujarat has depleted d<sup>18</sup>O compare to adjacent high elevated hard rock aquifer indicates irrigation return flow of deep static water.</p>

Nanofiltration of colored surface water: Quebec's experience

2003 ◽  
Vol 3 (5-6) ◽  
pp. 15-22
Author(s):  
P. Kouadio ◽  
M. Tétrault
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Membrane Fouling ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Quebec City ◽  
Water Regulation ◽  
Eastern Canada

Three colored surface water nanofiltration pilot-scale projects were conducted in the province of Quebec (eastern Canada), between November 2000 and March 2002, by the company H2O Innovation (2000) inc., for the municipalities of Lac Bouchette, Latulipe-et-Gaboury and Charlesbourg (now part of Quebec City). Results indicated that nanofiltration permeate quality has an advance on present drinking water regulation standard in Quebec, but important membrane fouling occurred. Fouling can be controlled by pretreatment and optimization of the operating conditions.

scholarly journals Modelling local patterns of child mortality risk: a Bayesian Spatio-temporal analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Alejandro Lome-Hurtado ◽  
Jacques Lartigue-Mendoza ◽  
Juan C. Trujillo
Keyword(s):  
High Risk ◽  
Mexico City ◽  
Child Mortality ◽  
Mortality Risk ◽  
Temporal Analysis ◽  
Health Concern ◽  
The North ◽  
Greater Mexico ◽  
Spatio Temporal ◽  
Child Mortality Rate

Abstract Background Globally, child mortality rate has remained high over the years, but the figure can be reduced through proper implementation of spatially-targeted public health policies. Due to its alarming rate in comparison to North American standards, child mortality is particularly a health concern in Mexico. Despite this fact, there remains a dearth of studies that address its spatio-temporal identification in the country. The aims of this study are i) to model the evolution of child mortality risk at the municipality level in Greater Mexico City, (ii) to identify municipalities with high, medium, and low risk over time, and (iii) using municipality trends, to ascertain potential high-risk municipalities. Methods In order to control for the space-time patterns of data, the study performs a Bayesian spatio-temporal analysis. This methodology permits the modelling of the geographical variation of child mortality risk across municipalities, within the studied time span. Results The analysis shows that most of the high-risk municipalities were in the east, along with a few in the north and west areas of Greater Mexico City. In some of them, it is possible to distinguish an increasing trend in child mortality risk. The outcomes highlight municipalities currently presenting a medium risk but liable to become high risk, given their trend, after the studied period. Finally, the likelihood of child mortality risk illustrates an overall decreasing tendency throughout the 7-year studied period. Conclusions The identification of high-risk municipalities and risk trends may provide a useful input for policymakers seeking to reduce the incidence of child mortality. The results provide evidence that supports the use of geographical targeting in policy interventions.

scholarly journals Spatio-Temporal Patterns of Mass Changes in Himalayan Glaciated Region from EOF Analyses of GRACE Data

2021 ◽  
Vol 13 (2) ◽  
pp. 265
Author(s):  
Harika Munagapati ◽  
Virendra M. Tiwari
Keyword(s):  
Temperature Anomaly ◽  
Mass Gain ◽  
Snow Accumulation ◽  
Empirical Orthogonal Functions ◽  
Total Water ◽  
Orthogonal Functions ◽  
Grace Data ◽  
Grace Satellite ◽  
Spatio Temporal ◽  
Gravity Recovery

The nature of hydrological seasonality over the Himalayan Glaciated Region (HGR) is complex due to varied precipitation patterns. The present study attempts to exemplify the spatio-temporal variation of hydrological mass over the HGR using time-variable gravity from the Gravity Recovery and Climate Experiment (GRACE) satellite for the period of 2002–2016 on seasonal and interannual timescales. The mass signal derived from GRACE data is decomposed using empirical orthogonal functions (EOFs), allowing us to identify the three broad divisions of HGR, i.e., western, central, and eastern, based on the seasonal mass gain or loss that corresponds to prevailing climatic changes. Further, causative relationships between climatic variables and the EOF decomposed signals are explored using the Granger causality algorithm. It appears that a causal relationship exists between total precipitation and total water storage from GRACE. EOF modes also indicate certain regional anomalies such as the Karakoram mass gain, which represents ongoing snow accumulation. Our causality result suggests that the excessive snowfall in 2005–2008 has initiated this mass gain. However, as our results indicate, despite the dampening of snowfall rates after 2008, mass has been steadily increasing in the Karakorum, which is attributed to the flattening of the temperature anomaly curve and subsequent lower melting after 2008.

scholarly journals Spatio-Temporal Variations in Phytoplankton Communities in Sediment and Surface Water as Reservoir Drawdown—A Case Study of Pengxi River in Three Gorges Reservoir, China

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 340
Author(s):  
Wenjuan Ouyang ◽  
Zhe Li ◽  
Jixiang Yang ◽  
Lunhui Lu ◽  
Jinsong Guo
Keyword(s):  
Surface Water ◽  
Algal Blooms ◽  
Maximum Flow ◽  
Total Carbon ◽  
Hydrodynamic Conditions ◽  
Reservoir Drawdown ◽  
River Reservoir ◽  
Reservoir Systems ◽  
Spatio Temporal ◽  
Maximum Flow Velocity

The resting stages of phytoplankton are usually regarded as the seed bank and source of harmful algal blooms because of the recruitment of phytoplankton from sediment to the water column under suitable environmental conditions. Information about resting stages of phytoplankton is abundant in shallow lakes and littoral sea; yet, studies on river–reservoir systems are rare. The river–reservoir continuum shows a unique structuring of longitudinal gradients of hydrological and hydrodynamic conditions. We hypothesized that the seed bank and algal blooms in reservoirs are influenced by the hydrodynamic conditions of each reservoir. We used Illumina Miseq sequencing to examine the spatio-temporal variation in the phytoplankton community in the sediment as reservoir drawdown and in surface water during algal blooms in Pengxi River, a tributary of China’s Three Gorges Reservoir. The results show that the cyanobacteria community in sediment is significantly influenced by temperature, total carbon, maximum flow velocity, and total phosphorous, the eukaryotic phytoplankton community in sediment is significantly influenced by total phosphorous, temperature, total carbon, maximum flow velocity, and total nitrogen. Additionally, the dominant species in sediment is significantly different from that in surface water during algal blooms. Our results suggest that the dominant species in surface water during algal blooms is more influenced by the environmental factors and hydrodynamic conditions in the water column than the seeds in the sediment. These findings are fundamental for further research on the influence of hydrodynamic conditions on algal blooms in artificially regulated river-reservoir systems.

scholarly journals Spatio-Temporal Characteristics and Obstacle Factors of the Urban-Rural Integration of China’s Shrinking Cities in the Context of Sustainable Development

2021 ◽  
Vol 13 (8) ◽  
pp. 4203
Author(s):  
Bin Du ◽  
Ying Wang ◽  
Jiaxin He ◽  
Wai Li ◽  
Xiaohong Chen
Keyword(s):  
Sustainable Development ◽  
Economic Efficiency ◽  
Formation Mechanisms ◽  
Shrinking Cities ◽  
The Sustainable Development ◽  
Factors Affecting ◽  
Temporal Characteristics ◽  
The North ◽  
Urban Rural ◽  
Spatio Temporal

Based on the fundamental concept of sustainable development, this study empirically analyzes the spatio-temporal characteristics, formation mechanisms and obstacle factors of the urban-rural integration of shrinking cities in China, from 2008 to 2018. The conclusions are as follows: the overall level of the urban-rural integration of shrinking cities in China is low; the internal differences of urban-rural integration are also small, and the changes are slow. Next, the space difference is high in the east and low in the west, high in the south and low in the north. Moreover, differences exist among different levels of urban agglomerations. Urban economic efficiency, urban resources and environment, urban social equity and rural economic efficiency are the main factors affecting the urban-rural integration of shrinking cities in China. Urban and rural economic efficiency are the two most prominent shortcomings that restrict the urban-rural integration of shrinking cities. The spatial resistance mode of each city is more than the two-system resistance; the main resistance of shrinking cities with a higher level of urban-rural integration also comes from the non-economic field. This study expands the research scope that up till now has ignored the discussion of urban-rural issues in the research of shrinking cities at home and abroad, and provides practical guidance for the sustainable development of shrinking cities in China.

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