scholarly journals Hydraulic Conductivity Estimation Using Low-Flow Purging Data Elaboration in Contaminated Sites

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 898
Author(s):  
Francesco Maria De Filippi ◽  
Silvia Iacurto ◽  
Flavia Ferranti ◽  
Giuseppe Sappa
Keyword(s):  
Hydraulic Conductivity ◽  
Unconfined Aquifer ◽  
Alluvial Aquifer ◽  
Water Levels ◽  
Low Flow ◽  
Contaminated Sites ◽  
Disposal Site ◽  
Large Area ◽  
Monitoring Wells ◽  
Groundwater Characterization

Hydrogeological characterization is required when investigating contaminated sites, and hydraulic conductivity is an important parameter that needs to be estimated. Before groundwater sampling, well water level values are measured during low-flow purging to check the correct driving of the activity. However, these data are generally considered only as an indicator of an adequate well purging. In this paper, water levels and purging flow rates were considered to estimate hydraulic conductivity values in an alluvial aquifer, and the obtained results were compared with traditional hydraulic conductivity test results carried on in the same area. To test the applicability of this method, data coming from 59 wells located in the alluvial aquifer of Malagrotta waste disposal site, a large area of 160 ha near Rome, were analyzed and processed. Hydraulic conductivity values were estimated by applying the Dupuit’s hypothesis for steady-state radial flow in an unconfined aquifer, as these are the hydraulic conditions in pumping wells for remediation purposes. This study aims to show that low-flow purging procedures in monitoring wells—carried out before sampling for groundwater characterization—represent an easy and inexpensive method for soil hydraulic conductivity estimation with good feasibility, if correctly carried on.

Using groundwater levels and Specific Yield to Estimate the Recharge, South of Erbil, Kurdistan Region, Iraq

2018 ◽  
Vol 7 (4) ◽  
pp. 191
Author(s):  
Sherwan Sh. Qurtas
Keyword(s):  
Unconfined Aquifer ◽  
Middle Part ◽  
Water Levels ◽  
Specific Yield ◽  
Aquifer System ◽  
Groundwater Levels ◽  
Monitoring Wells ◽  
Water Table Fluctuation Method ◽  
Recharge Estimation ◽  
Fluctuation Method

Recharge estimation accurately is crucial to proper groundwater resource management, for the groundwater is dynamic and replenished natural resource. Usually recharge estimation depends on the; the water balance, water levels, and precipitation. This paper is studying the south-middle part of Erbil basin, with the majority of Quaternary sediments, the unconfined aquifer system is dominant, and the unsaturated zone is ranging from 15 to 50 meters, which groundwater levels response is moderate. The purpose of this study is quantification the natural recharge from precipitation. The water table fluctuation method is applied; using groundwater levels data of selected monitoring wells, neighboring meteorological station of the wells, and the specific yield of the aquifers. This method is widely used for its simplicity, scientific, realistic, and direct measurement. The accuracy depends on the how much the determination of specific yield is accurate, accuracy of the data, and the extrapolations of recession of groundwater levels curves of no rain periods. The normal annual precipitation there is 420 mm, the average recharge is 89 mm, and the average specific yield is around 0.03. The data of one water year of 2009 and 2010 has taken for some technical and accuracy reasons.

scholarly journals Seismically induced changes in groundwater levels and temperatures following the ML5.8 (ML5.1) Gyeongju earthquake in South Korea

2021 ◽  
Author(s):  
Soo-Hyoung Lee ◽  
Jae Min Lee ◽  
Sang-Ho Moon ◽  
Kyoochul Ha ◽  
Yongcheol Kim ◽  
...  
Keyword(s):  
South Korea ◽  
Groundwater Level ◽  
Seismic Waves ◽  
Groundwater Resources ◽  
Fluid Pressure ◽  
Water Levels ◽  
Aquifer System ◽  
Groundwater Levels ◽  
Monitoring Wells ◽  
Gyeongju Earthquake

AbstractHydrogeological responses to earthquakes such as changes in groundwater level, temperature, and chemistry, have been observed for several decades. This study examines behavior associated with ML 5.8 and ML 5.1 earthquakes that occurred on 12 September 2016 near Gyeongju, a city located on the southeast coast of the Korean peninsula. The ML 5.8 event stands as the largest recorded earthquake in South Korea since the advent of modern recording systems. There was considerable damage associated with the earthquakes and many aftershocks. Records from monitoring wells located about 135 km west of the epicenter displayed various patterns of change in both water level and temperature. There were transient-type, step-like-type (up and down), and persistent-type (rise and fall) changes in water levels. The water temperature changes were of transient, shift-change, and tendency-change types. Transient changes in the groundwater level and temperature were particularly well developed in monitoring wells installed along a major boundary fault that bisected the study area. These changes were interpreted as representing an aquifer system deformed by seismic waves. The various patterns in groundwater level and temperature, therefore, suggested that seismic waves impacted the fractured units through the reactivation of fractures, joints, and microcracks, which resulted from a pulse in fluid pressure. This study points to the value of long-term monitoring efforts, which in this case were able to provide detailed information needed to manage the groundwater resources in areas potentially affected by further earthquakes.

Direct Push Technology and Application to Vertical Profiling of Hydraulic Conductivity in Unconsolidated Formations

2003 ◽  
Author(s):  
Wesley McCall ◽  
Thomas M. Christy ◽  
James J. Butler
Keyword(s):  
Hydraulic Conductivity ◽  
Test Data ◽  
Small Diameter ◽  
Cost Effective ◽  
Depth Interval ◽  
Contaminant Migration ◽  
Slug Tests ◽  
Monitoring Wells ◽  
Direct Push ◽  
Vertical Profiling

Direct push (DP) methods provide a cost-effective alternative to conventional rotary drilling for investigations in unconsolidated formations. DP methods are commonly used for sampling soil gas, soil and groundwater; installing small-diameter monitoring wells; electrical logging; cone penetration testing; and standard penetration tests. Most recently, DP methods and equipment for vertical profiling of formation hydraulic conductivity (K) have been developed. Knowledge of the vertical and lateral variations in K is integral to understanding contaminant migration and, therefore, essential to designing an adequate and effective remediation system. DP-installed groundwater sampling tools may be used to access discrete intervals of the formation to conduct pneumatic slug tests. A small-diameter (38mm OD) single tube protected screen device allows the investigator to access one depth interval per advancement. Alternatively, a larger diameter (54mm OD) dual-tube groundwater profiling system may be used to access the formation at multiple depths during a single advancement. Once the appropriate tool is installed and developed, a pneumatic manifold is installed on the top of the DP rod string. The manifold includes the valving, regulator, and pressure gauge needed for pneumatic slug testing. A small-diameter pressure transducer is inserted via an airtight fitting in the pneumatic manifold, and a data-acquisition device connected to a laptop computer enables the slug test data to be acquired, displayed, and saved for analysis. Conventional data analysis methods can then be used to calculate the K value from the test data. A simple correction for tube diameter has been developed for slug tests in highly permeable aquifers. The pneumatic slug testing technique combined with DP-installed tools provides a cost-effective method for vertical profiling of K. Field comparison of this method to slug tests in conventional monitoring wells verified that this approach provides accurate K values. Use of this new approach can provide data on three-dimensional variations in hydraulic conductivity at a level of detail that has not previously been available. This will improve understanding of contaminant migration and the efficiency and quality of remedial system design, and ultimately, should lead to significant cost reductions.

Relationship between Waterway Depth and Low-Flow Water Levels in Reaches below the Three Gorges Dam

2019 ◽  
Vol 145 (1) ◽  
pp. 04018032 ◽  
Author(s):  
Yunping Yang ◽  
Mingjin Zhang ◽  
Wanli Liu ◽  
Jianjun Wang ◽  
Xiaoxing Li
Keyword(s):  
Water Levels ◽  
Three Gorges Dam ◽  
Low Flow ◽  
Three Gorges ◽  
The Three Gorges ◽  
The Three Gorges Dam

Estimation of hydraulic conductivity of an unconfined aquifer using cokriging of GPR and hydrostratigraphic data

2001 ◽  
Vol 47 (2) ◽  
pp. 135-152 ◽  
Author(s):  
Erwan Gloaguen ◽  
Michel Chouteau ◽  
Denis Marcotte ◽  
Robert Chapuis
Keyword(s):  
Hydraulic Conductivity ◽  
Unconfined Aquifer

Rainfall and runoff characteristics in a karstic basin of China

2018 ◽  
Vol 10 (1) ◽  
pp. 117-129
Author(s):  
Chongxun Mo ◽  
Guiyan Mo ◽  
Junkai Qin ◽  
Ming Zhou ◽  
Qing Yang ◽  
...  
Keyword(s):  
Seasonal Pattern ◽  
Kendall Test ◽  
Water Levels ◽  
Low Flow ◽  
Vegetation Coverage ◽  
Annual Streamflow ◽  
Average Annual Change ◽  
Formation Conditions ◽  
Autumn And Winter ◽  
Opposite Tendency

Abstract This paper examines the rainfall and runoff characteristics in a karstic basin of China. The results indicated that the inner-annual distributions of rainfall and runoff were uneven and slightly different, as the concentration period of rainfall (from April to October) was earlier; there was a delay of about a month before the runoff (from May to September), and the concentrated volume accounted for 87% of annual precipitation or annual streamflow. Interannually, rainfall changed more significantly than runoff, the wet years lasted longer than the dry years (rainfall), while the high and low flow years were equal for runoff. In addition, judging from the value of the Mann-Kendall test, the average annual change of rainfall (−2.36) was more significant than that of runoff (−2.05), and the seasonal pattern of runoff maintained an opposite tendency in autumn and winter before 1990. The changes in runoff were mainly associated with rainfall and the formation conditions in the karstic area, and the reservoir in this basin should be operated with different flood limiting water levels, and the vegetation coverage should be improved.

Rapid morphological evolution during beach breaching and closure at a bar-built estuary

2021 ◽  
Author(s):  
Mara Orescanin ◽  
Tyonna McPherson ◽  
Paul Jessen
Keyword(s):  
Sediment Transport ◽  
River Discharge ◽  
Morphological Evolution ◽  
Water Levels ◽  
Low Flow ◽  
Long Term Stability ◽  
Erosion Rates ◽  
Discharge Rates ◽  
Elevation Changes ◽  
Elevated Water

<p>The Carmel River runs 58 km from the Santa Lucia Mountains through the Carmel Valley eventually entering a lagoon at Carmel River State Beach near Carmel, California, USA. During the dry summer months, the lagoon is closed, with no connection to the coastal ocean.  However, during the wet winter months, the river often breaches through the lagoon allowing water to freely flow between the river and Carmel Bay. Sediment transport, in part owing to river discharge and in part owing to ocean forcing (tides and waves), contributes heavily to whether the lagoon is open or closed: when there are low flow conditions, waves and tides can decrease flow rates in the breach, allowing sediment to settle. The sediment budget is expected to be a closed system, owing to the rocky headlands and long-term stability (no yearly regression or transgression) of the shoreline, despite managed attempts to control breach and closure timing. However, it is currently unknown 1) how velocity profiles evolve during breaching, and 2) how much sediment moves during such an event. The hypothesis is that the breach mouth can completely disappear and re-emerge over a single breach-closure cycle, leading to meter-scale daily accretion and erosion rates of berm height if berm elevation is significantly lower than the expected steady-state berm height. Furthermore, it is hypothesized that during active breaching, discharge rates through the breach channel are larger than upstream river discharge rates owing to elevated water levels within the back lagoon. This study uses a RiverSurveyor M9 Acoustic Doppler Profiler to measure outflow discharge and GPS topographic surveys to quantify elevation changes. A velocity profile can be built which will estimate the sediment transport potential within the breach. The information obtained will help identify and better understand the river discharge thresholds which contribute to frequent breaching as well as estimates of morphological evolution during breaching, which are currently unknown, and can assist in determining likelihood of successful managed breaching and closure events. </p>

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