scholarly journals Importance of including small-scale tile drain discharge in the calibration of a coupled groundwater-surface water catchment model

2013 ◽  
Vol 49 (1) ◽  
pp. 585-603 ◽  
Author(s):  
Anne Lausten Hansen ◽  
Jens Christian Refsgaard ◽  
Britt Stenhøj Baun Christensen ◽  
Karsten Høgh Jensen
Keyword(s):  
Surface Water ◽  
Small Scale ◽  
Water Catchment ◽  
Catchment Model

Managing the impacts of mining on Ghana’s water resources from a legal perspective

2018 ◽  
Vol 1 (3) ◽  
pp. 156-165 ◽  
Author(s):  
Nasirudeen Abdul Fatawu
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Environmental Protection Agency ◽  
Large Scale ◽  
Small Scale ◽  
Mining Activities ◽  
Protection Agency ◽  
Environmental Laws ◽  
Mining Areas ◽  
Legal Perspective

Recent floods in Ghana are largely blamed on mining activities. Not only are lives lost through these floods, farms andproperties are destroyed as a result. Water resources are diverted, polluted and impounded upon by both large-scale minersand small-scale miners. Although these activities are largely blamed on behavioural attitudes that need to be changed, thereare legal dimensions that should be addressed as well. Coincidentally, a great proportion of the water resources of Ghana arewithin these mining areas thus the continual pollution of these surface water sources is a serious threat to the environmentand the development of the country as a whole. The environmental laws need to be oriented properly with adequate sanctionsto tackle the impacts mining has on water resources. The Environmental Impact Assessment (EIA) procedure needs to bestreamlined and undertaken by the Environmental Protection Agency (EPA) and not the company itself.

scholarly journals Monitoring Lakes Surface Water Velocity with SAR: A Feasibility Study on Lake Garda, Italy

2021 ◽  
Vol 13 (12) ◽  
pp. 2293
Author(s):  
Marina Amadori ◽  
Virginia Zamparelli ◽  
Giacomo De Carolis ◽  
Gianfranco Fornaro ◽  
Marco Toffolon ◽  
...  
Keyword(s):  
Surface Water ◽  
Wind Waves ◽  
Test Site ◽  
Water Velocity ◽  
Surface Velocity ◽  
Medium Size ◽  
Small Scale ◽  
Lake Garda ◽  
Marine Applications

The SAR Doppler frequencies are directly related to the motion of the scatterers in the illuminated area and have already been used in marine applications to monitor moving water surfaces. Here we investigate the possibility of retrieving surface water velocity from SAR Doppler analysis in medium-size lakes. ENVISAT images of the test site (Lake Garda) are processed and the Doppler Centroid Anomaly technique is adopted. The resulting surface velocity maps are compared with the outputs of a hydrodynamic model specifically validated for the case study. Thermal images from MODIS Terra are used in support of the modeling results. The surface velocity retrieved from SAR is found to overestimate the numerical results and the existence of a bias is investigated. In marine applications, such bias is traditionally removed through Geophysical Model Functions (GMFs) by ascribing it to a fully developed wind waves spectrum. We found that such an assumption is not supported in our case study, due to the small-scale variations of topography and wind. The role of wind intensity and duration on the results from SAR is evaluated, and the inclusion of lake bathymetry and the SAR backscatter gradient is recommended for the future development of GMFs suitable for lake environments.

Effect of small-scale illegal mining on surface water and sediment quality in Ghana

2021 ◽  
pp. 1-26
Author(s):  
Humphrey Ferdinand Darko ◽  
Anthony Yaw Karikari ◽  
Anthony Appiah Duah ◽  
Bismark Awinbire Akurugu ◽  
Victor Mante ◽  
...  
Keyword(s):  
Surface Water ◽  
Sediment Quality ◽  
Small Scale ◽  
Illegal Mining ◽  
Water And Sediment ◽  
Water And Sediment Quality

scholarly journals Investigating patterns and controls of groundwater up-welling in a lowland river by combining Fibre-optic Distributed Temperature Sensing with observations of vertical hydraulic gradients

2012 ◽  
Vol 16 (6) ◽  
pp. 1775-1792 ◽  
Author(s):  
S. Krause ◽  
T. Blume ◽  
N. J. Cassidy
Keyword(s):  
Surface Water ◽  
Water Exchange ◽  
Structural Heterogeneity ◽  
Temperature Sensing ◽  
Small Scale ◽  
Lowland River ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Hydraulic Gradients ◽  
Cold Spots

Abstract. This paper investigates the patterns and controls of aquifer–river exchange in a fast-flowing lowland river by the conjunctive use of streambed temperature anomalies identified with Fibre-optic Distributed Temperature Sensing (FO-DTS) and observations of vertical hydraulic gradients (VHG). FO-DTS temperature traces along this lowland river reach reveal discrete patterns with "cold spots" indicating groundwater up-welling. In contrast to previous studies using FO-DTS for investigation of groundwater–surface water exchange, the fibre-optic cable in this study was buried in the streambed sediments, ensuring clear signals despite fast flow and high discharges. During the observed summer baseflow period, streambed temperatures in groundwater up-welling locations were found to be up to 1.5 °C lower than ambient streambed temperatures. Due to the high river flows, the cold spots were sharp and distinctly localized without measurable impact on down-stream surface water temperature. VHG patterns along the stream reach were highly variable in space, revealing strong differences even at small scales. VHG patterns alone are indicators of both, structural heterogeneity of the stream bed as well as of the spatial heterogeneity of the groundwater–surface water exchange fluxes and are thus not conclusive in their interpretation. However, in combination with the high spatial resolution FO-DTS data we were able to separate these two influences and clearly identify locations of enhanced exchange, while also obtaining information on the complex small-scale streambed transmissivity patterns responsible for the very discrete exchange patterns. The validation of the combined VHG and FO-DTS approach provides an effective strategy for analysing drivers and controls of groundwater–surface water exchange, with implications for the quantification of biogeochemical cycling and contaminant transport at aquifer–river interfaces.

Sensitivity Analysis of Hyporheic Exchange to Small Scale Changes In Gravel-Sand Flumebed Using A Coupled Groundwater-Surface Water Model

2020 ◽  
Author(s):  
Md Abdullah Al Mehedi ◽  
Nora Reichert ◽  
Frank Molkenthin
Keyword(s):  
Sensitivity Analysis ◽  
Surface Water ◽  
Reactive Transport ◽  
Time Integration ◽  
Longitudinal Direction ◽  
Numerical Approach ◽  
Hyporheic Exchange ◽  
Water Model ◽  
Small Scale ◽  
Flume Experiments

<p>Distribution of the hyporheic streamlines and residence time (HRT) is a crucial factor under streambed to understand the transport phenomena of environmental toxins, sediment metabolic rates in fluvial ecology as well as hydrological water budget. To quantify HRT, both the laboratory and numerical approach could serve as discerning tools. However, due to high heterogeneity in natural streambed sediment and topography, an efficient numerical model setup can prove to be pragmatic in comparison to tedious laboratory experiments for tracing streamlines. Moreover, repeatability of results, high amount of variation in the laboratory flumebed setup, greater insight into the 3D flow system and investigation possibilities with regard to individual streamlines or particular areas of HRT distribution cannot be well executed in laboratory. On the other hand, an automated generation of hyporheic streamlines with a range of various flumebed setups could propel a better understanding of the process and behavior of hyporheic streamlines and HRT distribution. Therefore, a robust numerical method could bestow to trace a large number of particles from various seeding locations at the flumebed. All of these facts enforce the necessity of numerical modeling of flume experiments to perceive the hyporheic exchange mechanisms at fieldwork and research, which are difficult to segregate under natural in-stream conditions. Keeping these issues in mind, we developed an automated numerical  method for quantifying the hyporheic exchange, where the surface water modeling software, HEC-RAS 5.0.5 and the subsurface flow and reactive transport code, MIN3P are coupled. A channel segment with a longitudinal dimension of 1 m and water surface elevation of 0.02 m is used for generating the hydraulic head distribution over the flumebed. A groundwater model domain of the dimensions of x:y:z = 1m:0.1m:0.1m is considered for the investigation of hyporheic exchange. A simple code for computing streamlines based on 4th order Runge-Kutta technique with the adaptive time integration method is developed using Matlab. Sensitivity analysis of streamline distribution and HRT to small scale changes (e.g. changes in dimension, distribution, and shape of the flumebed material) was performed, assuming a sand-gravel material mix. Various geometric shapes of gravel pieces (e.g. triangle, rectangle, trapezoid, and sphere) were used to vary the elevation of flumebed on a 1 mm scale. The results of the automated process show that the size, shape and distribution of trapezoidal gravel and sand portion in the streambed have a significant impact over hyporheic streamlines and HRT. High number and length of streamlines thus high HRT are found in case of the higher length of ridges created by the elevated portion of gravel pieces. In case of the increase of the length of gravel pieces along the longitudinal direction of flumebed, the length of streamlines and HRT decrease whereas the number of streamlines increase. Small scale hyporheic exchanges are found in case of increasing length of gravel pieces. Similar outcomes are also found for triangular and spherical gravel pieces. Both the number and length of streamlines are significantly reduced in case of the high number of gravel and sand portion on the streambed.</p>

Fourier and Wavelet Analysis of Water Quality Signals

2013 ◽  
Vol 765-767 ◽  
pp. 2848-2852
Author(s):  
Wei Zhang ◽  
Hong Li ◽  
Dan Feng Sun ◽  
Lian Di Zhou
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Wavelet Analysis ◽  
Temporal Pattern ◽  
Surface Water Quality ◽  
Small Scale ◽  
Analysis Method ◽  
Periodic Patterns ◽  
Quality Signals ◽  
Detailed Method

Taking the nitrogen monitoring data of two sites S1 and S2 in the period 1988-2003 in Baihe River lying Miyun reservoir stream watershed as a case, Fourier and Wavelet analysis were adopted to explore and compare the periodic patterns and temporal pattern characteristics of the two sites. The results showed that the periodic patterns of two sites were discovered using Fourier analysis. The site S1 had a period of two years, while the site S2 had no significant periodic patterns. The temporal pattern characteristics at different scales were obtained through wavelet analysis, which were at small scale for the site S1, while at moderate and small scales for the site S2. The Fourier and wavelet analysis method can both be used in the study of surface water quality temporal change pattern, the first is a coarse method and the latter is a more detailed method for analyzing surface water quality temporal pattern characteristics.

Validation Study of Road Surface Water Film Depth Prediction Model

2014 ◽  
Vol 1079-1080 ◽  
pp. 379-385 ◽  
Author(s):  
Jing Luo ◽  
Jian Bei Liu ◽  
Teng Feng Guo ◽  
Cheng Yu Hu
Keyword(s):  
Comparative Analysis ◽  
Surface Water ◽  
Film Thickness ◽  
Experimental Validation ◽  
Prediction Models ◽  
Water Film ◽  
Small Scale ◽  
Model Parameters ◽  
Water Film Thickness ◽  
Depth Prediction

Surface water film thickness is one of the main factors, which affect the vehicle safety on slippery roads. Water film depth is influenced by rainfall intensity, grades, cross slopes, drainage length and pavement texture. This paper reviews the research status and makes some comparative analysis of several pavement water film depth prediction models. An experimental validation has verified and calibrated the existing water film depth prediction models results. The experimental validation of the variable in the slope water flow model has been implemented by means of a small scale physical road model in a rainfall simulator, which is constructed in a laboratory. The results of comparative analysis have shown that in the existing water film depth prediction models, the regression models predict values are more closely than mathematical-physical models. Because under different experimental conditions, the regression model calibration parameters are different. In the case of specific road characteristics for prediction of water film thickness, the model parameters can be calibrated to further improve predicting accuracy.

Optimal extraction of small-scale surface water storage in Asia

1992 ◽  
Vol 28 (5) ◽  
pp. 1207-1219 ◽  
Author(s):  
S. Mahendrarajah ◽  
P. G. Warr ◽  
A. J. Jakeman
Keyword(s):  
Surface Water ◽  
Water Storage ◽  
Small Scale ◽  
Scale Surface ◽  
Surface Water Storage

scholarly journals Municipal management and geo-hydrological aspects of importance in the potable water supply of Lindley

2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Eric Nealer ◽  
W E Bertram
Keyword(s):  
Surface Water ◽  
South African ◽  
Potable Water ◽  
Service Providers ◽  
Municipal Government ◽  
Integrated Water Resources Management ◽  
Extensive Literature ◽  
Municipal Management ◽  
Potable Water Supply ◽  
Water Catchment

When the South African Government in 1998 re-demarcated its 283 municipalities so that they completely cover the country in a “wall-to-wall” manner, their main focus was on growing local economies and maintaining the provision of an increased number of diverse and more complex basic municipal services to new geographical areas consisting of millions of citizens who might previously had been neglected.In most of the instances the newly established and merged municipalities were demarcated according to geographical aspects inherited from the previous political dispensation, historical municipal areas and magisterial district farm names. The fact that these municipal government jurisdictions for the purpose of improving co-operative municipal- and integrated water resources management (IWRM), in most instances do not correspond with environmental and physical land features such as the demarcated surface water (rivers) drainage regions’ boundaries, could lead to the ineffective, inefficient and non-economic municipal management of water, sanitation and environmental services.The aforementioned is a case with reference to water services management in the Free State Province town of Lindley located in the Vals River catchment and the Nketoana Local Municipality’s area of jurisdiction.An extensive literature review, the use and study of geographic tools such as maps, ortho- photos and information data bases, as well as two field visits to the area, enabled the researchers to identify the essential geographical, geo-hydrological and municipal management aspects of importance for the potable water service providers and managers in the Lindley municipal area.The researchers argue that effective trans-boundary municipal management through simunye-type co-operative governance and IWRM must be facilitated in the Vals River surface water catchment between the respective local- and district municipalities for the benefit of the Lindley, Arlington, Steynsrus and Kroonstad communities.

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