scholarly journals Hydrological performance of lined permeable pavements in Norway

2021 ◽  
Author(s):  
Elhadi Mohsen Hassan Abdalla ◽  
Ingrid Selseth ◽  
Tone Merete Muthanna ◽  
Herman Helness ◽  
Knut Alfredsen ◽  
...  
Keyword(s):  
Initial Conditions ◽  
Shallow Groundwater ◽  
Design Tool ◽  
Reservoir Model ◽  
Peak Reduction ◽  
Infiltration Capacity ◽  
Groundwater Levels ◽  
Permeable Pavements ◽  
Flow Duration Curves ◽  
Generalized Likelihood Uncertainty Estimation

Abstract Lined permeable pavements (LPPs) are types of sustainable urban stormwater systems (SUDs) that are suitable for locations with low infiltration capacity or shallow groundwater levels. This study evaluated the hydrological performance of an LPP system in Norway using common detention indicators and flow duration curves (FDCs). Two hydrological models, the Storm Water Management Model (SWMM)-LID module and a reservoir model, were applied to simulate continuous outflows from the LPP system to plot the FDCs. The sensitivity of the parameters of the SWMM-LID module was assessed using the generalized likelihood uncertainty estimation methodology. The LPP system was found to detain the flow effectively based on the median values of the detention indicators (peak reduction = 89%, peak delay = 40 min, centroid delay = 45 min, T50-delay = 86 min). However, these indicators are found to be sensitive to the amount of precipitation and initial conditions. The reservoir model developed in this study was found to yield more accurate simulations (higher NSE) than the SWMM-LID module, and it can be considered a suitable design tool for LPP systems. The FDC offers an informative method to demonstrate the hydrological performance of LPP systems for stormwater engineers and decision-makers.

scholarly journals Shallow groundwater in sub-Saharan Africa: neglected opportunity for sustainable intensification of small-scale agriculture?

2016 ◽  
Author(s):  
John Gowing ◽  
Geoff Parkin ◽  
Nathan Forsythe ◽  
David Walker ◽  
Alemseged Tamiru Haile ◽  
...  
Keyword(s):  
Groundwater Resources ◽  
Climatic Variability ◽  
Shallow Groundwater ◽  
Sustainable Intensification ◽  
Sub Saharan Africa ◽  
Small Scale ◽  
Groundwater Levels ◽  
Sub Saharan ◽  
Small Scale Irrigation

Abstract. There is a need for an evidence-based approach to identify how best to support development of groundwater for small scale irrigation in sub-Saharan Africa (SSA). We argue that it is important to focus this effort on shallow groundwater resources which are most likely to be used by poor rural communities in SSA. However, it is important to consider constraints, since shallow groundwater resources are likely to be vulnerable to over-exploitation and climatic variability. We examine here the opportunities and constraints and draw upon evidence from Ethiopia. We present a methodology for assessing and interpreting available shallow groundwater resources and argue that participatory monitoring of local water resources is desirable and feasible. We consider possib le models for developing distributed small-scale irrigation and assess its technical feasibility. Because of power limits on water lifting and also because of available technology for well construction, groundwater at depths of 50 m or 60 m cannot be regarded as easily accessible for small-scale irrigation. We therefore adopt a working definition of shallow groundwater as < 20 m depth. This detailed case study in the Dangila woreda in Ethiopia explores the feasibility of exploiting shallow groundwater for small-scale irrigation over a range of rainfall conditions. Variability of rainfall over the study period (9 % to 96 % probability of non-exceedance) does not translate into equivalent variability in groundwater levels and river baseflow. Groundwater levels, monitored by local communities, persist into the dry season to at least the end of December in most shallow wells, indicating that groundwater is available for irrigation use after the cessation of the wet season. Arguments historically put forward against the promotion of groundwater use for agriculture in SSA on the basis that aquifers are unproductive and irrigation will have unacceptable impacts on wetlands and other groundwater-dependent ecosystems appear exaggerated. It would be unwise to generalise from this case study to the whole of SSA, but useful insights into the wider issues are revealed by the case study approach. We believe there is a case for arguing that shallow groundwater in sub-Saharan Africa represents a neglected opportunity for sustainable intensification of small-scale agriculture.

scholarly journals Groundwater recharge processes in an Asian mega-delta: hydrometric evidence from Bangladesh

2020 ◽  
Vol 28 (8) ◽  
pp. 2917-2932
Author(s):  
Sara Nowreen ◽  
R. G. Taylor ◽  
M. Shamsudduha ◽  
M. Salehin ◽  
A. Zahid ◽  
...  
Keyword(s):  
Groundwater Recharge ◽  
Conceptual Models ◽  
Shallow Groundwater ◽  
Depositional Environments ◽  
Series Data ◽  
Groundwater Depletion ◽  
Bengal Basin ◽  
River Channels ◽  
Groundwater Levels ◽  
Pleistocene Aquifer

AbstractGroundwater is used intensively in Asian mega-deltas yet the processes by which groundwater is replenished in these deltaic systems remain inadequately understood. Drawing insight from hourly monitoring of groundwater levels and rainfall in two contrasting settings, comprising permeable surficial deposits of Holocene age and Plio-Pleistocene terrace deposits, together with longer-term, lower-frequency records of groundwater levels, river stage, and rainfall from the Bengal Basin, conceptual models of recharge processes in these two depositional environments are developed. The representivity of these conceptual models across the Bengal Basin in Bangladesh is explored by way of statistical cluster analysis of groundwater-level time series data. Observational records reveal that both diffuse and focused recharge processes occur in Holocene deposits, whereas recharge in Plio-Pleistocene deposits is dominated by indirect leakage from river channels where incision has enabled a direct hydraulic connection between river channels and the Plio-Pleistocene aquifer underlying surficial clays. Seasonal cycles of recharge and discharge including the onset of dry-season groundwater-fed irrigation are well characterised by compiled observational records. Groundwater depletion, evident from declining groundwater levels with a diminished seasonality, is pronounced in Plio-Pleistocene environments where direct recharge is inhibited by the surficial clays. In contrast, intensive shallow groundwater abstraction in Holocene environments can enhance direct and indirect recharge via a more permeable surface geology. The vital contributions of indirect recharge of shallow groundwater identified in both depositional settings in the Bengal Basin highlight the critical limitation of using models that exclude this process in the estimation of groundwater recharge in Asian mega-deltas.

scholarly journals Spatial variability of shallow groundwater level in the Northern Kathmandu Valley

2018 ◽  
Vol 55 (1) ◽  
pp. 45-54
Author(s):  
Manish Shrestha ◽  
Naresh Kazi Tamrakar
Keyword(s):  
Groundwater Level ◽  
Shallow Groundwater ◽  
Soil Surface ◽  
Northern Region ◽  
Dry Season ◽  
Kathmandu Valley ◽  
Wet Season ◽  
Geological Material ◽  
Groundwater Levels ◽  
Shallow Groundwater Level

Groundwater is the water which is present in pore spaces and in the fractures of the geological materials beneath earth surface. Water is incompressible substance and presence of small amount of water in geological material modifies the behavior of geological material under stresses. Determination of engineering behavior of the geological material is almost impossible skipping the role of water. The objective of this study was to map and evaluate shallow groundwater level of the northern Kathmandu Valley covering main rivers such as the Bagmati River, Bishnumati River, Dhobi Khola and the Manahara Khola. These rivers flow from the North to the South across the sand rich sediment zone. Static groundwater levels of 239 wells were measured from different locations of the study area in April/March 2017 (Dry Season) and in August 2017 (Wet Season). Shallow groundwater level was measured from soil surface to water level using well water depth logger (Qin and Li, 1998). The result showed that groundwater level ranged from 0.6 m to 12.5 m in dry season and 0.1 m to 13 m in wet season. The groundwater level increased by average of 34.68% (n = 235) as compared to that in dry season. Increase in the groundwater level suggests recharge of groundwater in wet season of the study area. The flow pattern of groundwater levels from the study shows flow of shallow groundwater towards the major rivers of that particular river watershed. As a consequence, seepage flow and piping erosion is likely along the riverbank slopes. Increase in recharge of groundwater during wet season exhibits that the northern region of the Kathmandu Valley is potential for groundwater recharge and can be used to manage water for the dry period.

Modelling the response of shallow groundwater levels to combined climate and water-diversion scenarios in Beijing-Tianjin-Hebei Plain, China

2017 ◽  
Vol 25 (6) ◽  
pp. 1733-1744 ◽  
Author(s):  
Xue Li ◽  
Si-Yuan Ye ◽  
Ai-Hua Wei ◽  
Peng-Peng Zhou ◽  
Li-Heng Wang
Keyword(s):  
Shallow Groundwater ◽  
Water Diversion ◽  
Groundwater Levels ◽  
Hebei Plain

Shallow groundwater dynamics in smectite dominated clay on the Liverpool Plains of New South Wales

Soil Research ◽  
2001 ◽  
Vol 39 (2) ◽  
pp. 203 ◽  
Author(s):  
W. Timms ◽  
R. I. Acworth ◽  
D. Berhane
Keyword(s):  
New South ◽  
Regional Scale ◽  
New South Wales ◽  
Shallow Groundwater ◽  
Important Indicator ◽  
Groundwater Levels ◽  
South Wales ◽  
Aquifer Systems ◽  
North Eastern ◽  
Shallow Groundwater System

Dynamic shallow (<5 m) groundwater levels are an important indicator of water and salt fluxes in smectite-dominated clay on the Liverpool Plains in north-eastern New South Wales. Previous hydrogeological assessments of shallow groundwater related salinity risk have focused on regional scale distribution and interaction with rising pressure levels in confined aquifer systems. In this study, groundwater levels over a 7-year period for the saline Yarramanbah subcatchment are presented, along with data from 60 new and existing shallow piezometers and precise elevation surveying and intensive automated monitoring at selected sites. The shallow groundwater system is shown to respond to recharge; however, over the medium-term it is in hydrologic balance, with no evidence of increased water storage. A proportion of recharge is lost by discharge into deeply incised surface channels. Groundwater salinity in the banks of Warrah Creek indicate that flushing of salts from clay is related to increased flux of fresh water. Concern exists that there may be increased salt export from the catchment. If this is in fact occurring while the plains are in hydrologic equilibrium, then increased salt fluxes must be related to factors other than rising groundwater levels.

Evaluation of the saturated–unsaturated groundwater conditions of a thickened tailings deposit

1993 ◽  
Vol 30 (6) ◽  
pp. 935-946 ◽  
Author(s):  
S. Lee Barbour ◽  
G. Ward Wilson ◽  
L.C. St-Arnaud
Keyword(s):  
Atmospheric Oxygen ◽  
Shallow Groundwater ◽  
Groundwater Levels ◽  
Acid Generation ◽  
Zinc Mine ◽  
Retention Characteristics ◽  
Copper Zinc ◽  
Rate Of Evaporation ◽  
Thickened Tailings

The method of thickened tailings disposal has been in use at an active copper–zinc mine near Timmins, Ontario, for approximately 25 years. The thickened tailings deposit that has been formed was investigated. Field and laboratory tests were conducted to determine particle-size distribution at various horizontal locations, in situ values of hydraulic conductivity, moisture-retention characteristics, groundwater levels, and in situ water contents. The results of the investigation show that the thickened tailings deposit is relatively homogeneous. Shallow groundwater levels were also observed to follow the gently sloping topography of the tailings surface. Upward-seepage analyses were conducted for various steady-state evaporative fluxes. The analyses showed the tailings tend to maintain saturated conditions for the highest potential rate of evaporation observed. The ability of the tailings to maintain saturation is attributed to the shallow groundwater levels and the high air-entry value of the tailings. The tendency to saturated conditions at the tailings surface is a positive result. Saturated conditions in the tailings minimize the diffusion of atmospheric oxygen into the tailings. This aids in the prevention of acid generation in these tailings, which have the potential to oxidize and produce acid drainage. Key words : tailings, saturation, evaporation, acid generation.

scholarly journals Characterization of Infiltration Capacity of Permeable Pavements with Porous Asphalt Surface Using Cantabrian Fixed Infiltrometer

2012 ◽  
Vol 17 (5) ◽  
pp. 597-603 ◽  
Author(s):  
Jorge Rodriguez-Hernandez ◽  
Daniel Castro-Fresno ◽  
Andrés H. Fernández-Barrera ◽  
Ángel Vega-Zamanillo
Keyword(s):  
Infiltration Capacity ◽  
Porous Asphalt ◽  
Permeable Pavements

Seasonal variation in the microbial quality of shallow groundwater in the Kathmandu Valley, Nepal

2013 ◽  
Vol 14 (3) ◽  
pp. 390-397 ◽  
Author(s):  
Sadhana Shrestha ◽  
Takashi Nakamura ◽  
Rabin Malla ◽  
Kei Nishida
Keyword(s):  
Groundwater Level ◽  
Seasonal Variations ◽  
Shallow Groundwater ◽  
Dry Season ◽  
Kathmandu Valley ◽  
Microbial Quality ◽  
Wet Season ◽  
Groundwater Levels ◽  
E Coli

To develop effective groundwater pollution control strategies for the Kathmandu Valley, Nepal, seasonal variations in microbial quality and their underlying mechanisms must be understood. However, to date, there are no studies that address these topics. In this study, groundwater samples from dug wells were collected during the dry and wet seasons from 2009 to 2012, and Escherichia coli (E. coli) and total coliforms were analysed. Three wells were monitored each month for a year. Microbial concentrations in shallow groundwater were significantly higher during the wet season than during the dry season. Analyses of rainfall and E. coli concentrations in different seasons indicated that a high level of faecal material infiltration during the rainy season may have caused the seasonal variations in microbial quality. A moderate to strong relationship between E. coli concentrations and groundwater level suggested that the rise in groundwater levels during the wet season may be another reason for this variation. This long time-scale survey detected a significant decline in the microbial quality of shallow groundwater during the wet season as compared with the dry season. We propose that the infiltration of contaminants and change in groundwater level are the two probable mechanisms for the observed seasonal differences.

scholarly journals Modelling single- and tandem-bubble dynamics between two parallel plates for biomedical applications

2013 ◽  
Vol 716 ◽  
pp. 137-170 ◽  
Author(s):  
C.-T. Hsiao ◽  
J.-K. Choi ◽  
S. Singh ◽  
G. L. Chahine ◽  
T. A. Hay ◽  
...  
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Bubble Dynamics ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Design Tool ◽  
Parallel Plates ◽  
Jet Formation ◽  
Viscous Boundary Layer ◽  
Element Method

AbstractCarefully timed tandem microbubbles have been shown to produce directional and targeted membrane poration of individual cells in microfluidic systems, which could be of use in ultrasound-mediated drug and gene delivery. This study aims at contributing to the understanding of the mechanisms at play in such an interaction. The dynamics of single and tandem microbubbles between two parallel plates is studied numerically and analytically. Comparisons are then made between the numerical results and the available experimental results. Numerically, assuming a potential flow, a three-dimensional boundary element method (BEM) is used to describe complex bubble deformations, jet formation, and bubble splitting. Analytically, compressibility and viscous boundary layer effects along the channel walls, neglected in the BEM model, are considered while shape of the bubble is not considered. Comparisons show that energy losses modify the bubble dynamics when the two approaches use identical initial conditions. The initial conditions in the boundary element method can be adjusted to recover the bubble period and maximum bubble volume when in an infinite medium. Using the same conditions enables the method to recover the full dynamics of single and tandem bubbles, including large deformations and fast re-entering jet formation. This method can be used as a design tool for future tandem-bubble sonoporation experiments.

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