Groundwater Monitoring System Research Articles

Geoinformation technologies and methods of mathematical modeling in hydrogeological research

In the article the application issues of geographic information technologies and methods of mathematical modeling of geofiltration and geomigration processes of hydrogeological systems were discussed, as well as for information support of the groundwater monitoring system. The object of research is the Akhangaran aquifer, which is a large industrial area with intensification of agriculture, as well as densely populated, where industrial reproduction of water resources is established by designing water intake facilities using groundwater, also having huge data on regime, geological and hydrogeological aspects. The main goal of these researches is to learn the methodology for assessing groundwater resources by modeling to the GIS basis, theoretical and applied methods of mathematical analyses. The features are considered and the boundary and initial conditions are justified. The results are a research technique has been developed to simulate geofiltration and geomigration processes, to determine the balance of groundwater, and the hydrogeological parameters of the aquifer have been calculated from it. The calculated values of the natural resources of groundwater by the parameters of their level mode in the Akhangaran pool allowed establish the permissible convergence of resource estimates according to the amplitudes of fluctuations in the level of groundwater and according to geoinformation modeling.

Geostatistical analysis and optimization of the state hydrogheological monitoring network within the Pripyat river basin (Ukraine)

Formulation of the problem. The State Hydrogeological Monitoring Network has to provide the necessary information to manage groundwater resources and prevent negative changes in the geological environment. Currently, there is a negative tendency to decrease the number of observation wells, loss of information about the space-time variability of the hydrogeological regime elements in Ukraine. In conditions of limited funding, an important task is to develop an effective strategy for reforming the hydrogeological monitoring system, taking into account international experience and based on modern geoinformation technologies. Particular attention has to be given to transboundary territories. One of them is the Pripyat River basin, which is characterized by the low level of the State Hydrogeological Monitoring Network representativeness, both in comparison with European Union standards and with the existing groundwater monitoring network of neighbouring Belarus. The purpose of the article is to evaluate the actual state of the hydrogeological observation wells network and optimize it within the territory of the Ukrainian part of the transboundary Pripyat watershed basin. Methodology and materials. The State Scientific and Production Enterprise "Geoinform of Ukraine" database of State Groundwater Monitoring System composition and functioning as well as zoning map under the conditions of water exchange formation in the upper water-bearing level were used for the study. For the studied territory of the water exchange basin of Pripyat, the analysis of density and uniformity of the observation points distribution as well as the variogram analysis of the spatial distribution of groundwater-level altitudes within the study area were carried. For the actual monitoring network, the expected error of the spatial modelling of the groundwater-surface was evaluated. Results. The obtained results of the geostatistical analysis made it possible to substantiate the project wells locations within the water exchange sub-basins to improve the quality of hydrogeological monitoring problem solutions. Scientific novelty. The method of the hydrogeological monitoring network optimization has been improved based on geoinformation and geostatistical approaches and implemented for the Ukrainian part of the Pripyat River basin, taking into account the hydrogeological conditions of the territory and the configuration of the existing network. Practical significance. Optimization and increment of the observation wells network, taking into account the obtained results, will provide the effective functioning of the hydrogeological monitoring system within the Ukrainian part of the Pripyat River basin and will have an economic effect, given that the cost of any measures to improve the groundwater quality and quantity is far more expensive than the monitoring system optimization.

Penentuan Jaringan Sumur Pantau Primer Dengan Metode Inverse Distance Weighting Di Cekungan Air Tanah Jakarta

The increasing demand of raw water in DKI Jakarta has caused excessive groundwater abstraction. It causes the groundwater level drop to certain level and has emerged cone of depression in some areas. Groundwater management as an effort to recover the groundwater level, requires an integrated groundwater monitoring system. Recently, there are approximately 161 groundwater monitoring wells in Jakarta groundwater basin. Those wells are generally categorized as secondary network, since determined by groundwater abstraction activity. Meanwhile, a representative primary network to monitor the natural condition of groundwater in each aquifer layer is not yet available completely. The method of Inverse Distance Weighting (IDW) spatial estimation is applied to determine the number and distribution of primary monitoring wells based on aquifer geometry using Groundwater Modeling System (GMS) software. Based on the aquifer geometry, it can be arranged monitoring zones and the number of monitoring wells in each zone. There are 9 monitoring zones in Jakarta groundwater basin consist of 1 zone with 1 monitoring well, 2 zones with 2 monitoring wells, 3 zones with 3 monitoring wells, and 3 zones with 4 monitoring wells, so that the total of primary monitoring wells for groundwater monitoring in Jakarta groundwater basin is 26 monitoring wells. This research is expected to be useful for stakeholders to optimize the representative monitoring wells network based on aquifer geometry in sustainable groundwater management.

Groundwater Quality Analyses along Kenyan Coastal Region, Case Study of Kilifi County

The Kenyan coast is a semi-arid region frequently faced with severe water scarcity especially during prolonged drought and a rapid population growth. Groundwater provides 50% of the water demand and most sources are poorly drilled, over-abstracted and abandoned. The aquifers occur in sedimentary formations of fluvial and lacustrine origin. There is a need to have a groundwater monitoring system in place; therefore this study analyses selected physico- chemical and microbial parameters using both laboratory and field methods. Arc-GIS 9.3, SURFER were used to generate thematic maps for some tested parameters. Results indicate pH values within acceptable range of 6.5 – 8.5, though shallow wells in Malindi were acidic, this atrributed to the heavy industries prevalent in the area. Electric conductivity (EC) was above the set standard of 1500µS/m indicating high dissolved ions present especially in Magarini where salt mining is done. Total dissolved solids (TDS) of up to 500mg/L suitable for drinking water was only found during the wet season. Turbidity of less than 5 NTU was established in most areas. Chlorides and salinity levels exceeded 250mg/L pointing to the saltwater intrusion problem that is a challenge along Kenyan coastal aquifers Boreholes and shallow wells had a total hardness ranging from 50mg/L -150mg/L indicating the water was ranging from being slightly hard to hard water. Escheriria coli was present in almost all the boreholes and shallow wells indicating the need to treat water before use. Water Quality index (WQI) calculation indicate that groundwater is unsuitable for human consumption in dry season.

Identifying hotspots and representative monitoring area of groundwater changes with time stability analysis

Groundwater is a most accessible freshwater resource for human beings, and it is increasingly important as an alternative to surface water under the threat of climate change. However, its complex spatio-temporal dynamic remains unattended from management perspective. Past studies on groundwater management were stalled by a relative dearth of high-quality data and a lack of synthetic analysis on both spatial and temporal information. Thanks to NASA's launch of Gravity Recovery and Climate Experiment (GRACE) satellite mission, our study has solved these two problems by innovatively applying time stability analysis to GRACE-based groundwater data. Taking the Yellow River Basin (YRB) as an example, we employed GRACE satellite data to obtain monthly changes of groundwater tables from Jan. 2003 to Dec. 2016 in 1.0-degree grid of spatial resolution. Then we identified hotspots (which indicated severe groundwater declines and fluctuations over time) and representative monitoring areas (which stably represented the spatial average over time) using time stability analysis. Time stability employs multiple coefficients to identify the spatial relations between local variables and global variables overtime, thus showing the overall effect of spatial-wise and temporal-wise factors but never used in groundwater studies before. Based on this innovative method, we further identified management categories across the YRB using multivariate cluster analysis. As a result, the YRB has been divided into five zones for different management strategies. We identified the hotspots in west-most and east-most areas of the YRB, where we suggest a strengthened groundwater protections and risk response system. The northern part of the middle reach in the YRB was also identified as the representative monitoring areas. With these knowledge, decision-makers can have a clearer regional plan for groundwater protection, monitoring, and risk response system. This new method enables a quick decision on the prioritized areas for different groundwater management strategies while not losing the scope of spatio-temporal heterogeneity.

Multilayer arsenic mobilization and multimetal co-enrichment in the alluvium (Brahmaputra) plains of India: A tale of redox domination along the depth

The study attempts to understand arsenic (As) mobilization in a shallow aquifer with depth variation while focusing on the potential co-occurrence of As with priority metals (zinc and lead), using a pilot scale multilevel groundwater monitoring system (MGWS). Groundwater samples (n = 72) were collected bi-weekly (every 15 days) from the multilevel sampler (4.6, 9.2 and 13.8 m depths), installed at Tezpur, Sonitpur district of Brahmaputra floodplain (BFP), Assam, India, for a period of 1 year (August 2013–July 2014). Both geogenic and anthropogenic influences were found to affect the studied unconfined aquifer. At 4.6 m, weathering dominated due to interaction with CO2 and infiltrating water. Prevalent high pH (7.9–8.6) at all three depths in association with strong oxidizing condition (at 4.6 m) during the drier months seem to play a crucial role in desorption based As release. Multivariate analyses revealed that redox potential (ORP) remains the primary controller of As release at all three depths. With depth, stronger anoxic conditions resulted in the dominance of reductive hydrolysis leading to a co-occurrence scenario of As (max 4.6 μgL−1) with Zn (max 2514 μgL−1) and Pb (max 740 μL−1) with influences of anthropogenic modes of activities like agriculture and dry deposition from a brick kiln. Multi-element enrichment is an emerging concern but the bigger picture would be to understand the peculiarities of individual aquifers, as a generalization can lead to missing a ton of information. In this regard, long-term multilevel monitoring can help in the predictive understanding of the vertical stratification and co-occurrences of multi-metals that can subsequently be applied for water production at the safer depths.

Review: Challenges and opportunities for sustainable groundwater management in Africa

Groundwater plays a fundamental yet often little appreciated role in supporting economic development and human well-being in both urban and rural environments, as well as supporting many aquatic ecosystems in Africa. Thus, groundwater has high relevance to the development and well-being of Africa, if adequately assessed and sustainably exploited. Whilst the potential for groundwater-resources development continues to be reported in the literature, a quantitative understanding of these issues remains poor. The objective of this paper is to highlight the main groundwater issues and problems in Africa and the current and expected opportunities for sustainable groundwater management. This will be done through the review of existing knowledge of groundwater resources and of ongoing and planned groundwater management programs and initiatives. Groundwater resources in Africa face increasing threat of pollution from urbanisation, industrial development, agricultural and mining activities, and from poor sanitation practices and over-exploitation due to increasing demand to meet human and agricultural needs. However, despite the existence of a number of groundwater management challenges, groundwater resources in Africa are still generally under-developed and can meet the various needs in a sustainable manner if better managed. Thus, strategies to ensure sustainable development and management of groundwater resources need to be put in place. These include establishment of groundwater monitoring systems, understanding of the groundwater–aquatic ecosystem relationships, management of transboundary aquifers, addressing climate-change impacts on groundwater, assessing the impact of increased pumping from various types of aquifers on sustainability of groundwater abstraction, and capacity building in groundwater management.

Suitability analysis of saline water intrusion monitoring wells near a waterway based on a numerical model and electric conductivity time series

A strategy to transport freshwater mixed with seawater in the Gyeongin-Ara Waterway was established to improve and maintain the water quality. Saline water in a canal can cause its spread into the surrounding aquifer and therefore a groundwater monitoring system is essential to detect this phenomenon. Thirty-four monitoring wells were proposed based on the distribution of the chloride concentration estimated with a numerical model, and 29 wells were finally constructed as close to the proposed sites as possible. Multi-depth monitoring sensors were installed at 11 wells to measure the vertical spread of saline water. Principal component analysis and a comparison of actual measurements and model-estimated values for electric conductivity showed that the locations of the monitoring wells were appropriate for detecting the salinity spreading in groundwater.

Colorado Water Watch: real-time groundwater monitoring for possible contamination from oil and gas activities

Currently, only a few states in the USA (e.g., Colorado and Ohio) require mandatory baseline groundwater sampling from nearby groundwater wells prior to drilling a new oil or gas well. Colorado is the first state to regulate groundwater testing before and after drilling, which requires one pre-drilling sample and two additional post-drilling samples within 6-12months and 5-6years of drilling. However, the monitoring method is limited to the state's regulatory agency and to ex situ sampling, which offers only a snapshot in time. To overcome the limitations and increase monitoring performance, a new groundwater monitoring system, Colorado Water Watch (CWW), was introduced as a decision-making tool to support the state's regulatory agency and also to provide real-time groundwater quality data to both the industry and the public. The CWW uses simple in situ water quality sensors based on the surrogate sensing technology that employs an event detection system to screen the incoming data in near real-time.

A spatiotemporal Bayesian maximum entropy-based methodology for dealing with sparse data in revising groundwater quality monitoring networks: the Tehran region experience

Data inadequacy is a common problem in designing or updating groundwater monitoring systems. The developed methodologies for the optimal design of groundwater monitoring systems usually assume that there is a complete set of data obtained from existing monitoring wells and provide a revised configuration for the system by analyzing the current data. These methodologies are not usually applicable when the current groundwater quantity and quality data are highly sparse. In this paper, a new simulation–optimization approach based on Bayesian maximum entropy theory (BME) is proposed for revising spatial and temporal monitoring frequencies in a sparsely monitored aquifer. The BME is used to simulate the spatial and spatiotemporal variations of groundwater indicators, incorporating the space/time uncertainties due to insufficient data. Comparing the obtained estimations with observations, the best BME model was selected to be linked with an optimization model. The main goal of optimization was to find out the spatial and temporal sampling characteristics of the monitoring stations using the concepts of Entropy theory and a groundwater vulnerability index. The results show the BME estimations are less biased and more accurate than Ordinary Kriging in both spatial and spatiotemporal analysis. The improvements in the BME estimates are mostly related to incorporating hard (accurate) and soft (uncertain) data in the estimation process. The applicability and efficiency of the proposed methodology have been evaluated by applying it to the Tehran aquifer in Iran which is suffering from high groundwater table fluctuations and nitrate pollution. Based on the results, in addition to the existing monitoring wells, seven new monitoring stations have been proposed. Few stations which potentially can be removed or combined with other stations have been identified and a monthly sampling frequency has been suggested.

Accidental infrastructure for groundwater monitoring in Africa

A data deficit in shallow groundwater monitoring in Africa exists despite one million handpumps being used by 200 million people every day. Recent advances with “smart handpumps” have provided accelerometry data sent automatically by SMS from transmitters inserted in handles to estimate hourly water usage. Exploiting the high-frequency “noise” in handpump accelerometry data, we model high-rate wave forms using robust machine learning techniques sensitive to the subtle interaction between pumping action and groundwater depth. We compare three methods for representing accelerometry data (wavelets, splines, Gaussian processes) with two systems for estimating groundwater depth (support vector regression, Gaussian process regression), and apply three systems to evaluate the results (held-out periods, held-out recordings, balanced datasets). Results indicate that the method using splines and support vector regression provides the lowest overall errors. We discuss further testing and the potential of using Africa's accidental infrastructure to harmonise groundwater monitoring systems with rural water-security goals.

Colorado Water Watch: Real-Time Groundwater Monitoring for Possible Contamination from Oil and Gas Activities

Currently, only a few states in the U.S. (e.g. Colorado and Ohio) require mandatory baseline groundwater sampling from nearby groundwater wells prior to drilling a new oil or gas well. Colorado is the first state to regulate groundwater testing before and after drilling, requiring one pre-drilling sample and two additional post-drilling samples within 6 - 12 months and 5 - 6 years of drilling, respectively. However, the monitoring method is limited to ex-situ sampling, which offers only a snapshot in time. To overcome the limitations and increase monitoring effectiveness, a new groundwater monitoring system, Colorado Water Watch (CWW), was introduced as a decision-making tool to support the state’s regulatory agency and also to provide real-time groundwater quality data to both industry and the public. The CWW uses simple in-situ water quality sensors based on surrogate sensing technology that employs an event detection system to screen the incoming data in near real-time. This objective of this study was to improve the understanding of groundwater quality in Wattenberg field and assess event detection methods. The data obtained from 5 sites (the earliest monitoring sites in the CWW network) for 3 years of the regional monitoring network in Wattenberg field is used to illustrate the background information about groundwater quality and its changing trend, and make comparisons between two outlier detection methods, CANARY and simple moving median.

Bucharest city urban groundwater monitoring system

Abstract Bucharest City is the capital of Romania and also the biggest city. Situated in an alluvial plane, the geological settings are represented by a series of overlaying Quaternary strata of aquifers and aquitards. Some of these aquifers are used for water supply (the deeper aquifers) and the shallow and medium ones are characterized by an intense interaction with the urban infrastructure. The paper presents the drivers and also the architecture of the urban groundwater monitoring systems developed in the last years in order to observe the urban impact upon the first two aquifers layers. The anatomy of the system is correlated with the urban infrastructure. Also the paper presents the future monitoring system that will be develop within a European JPI project.

Numerical study based on one-year monitoring data of groundwater-source heat pumps primarily for heating: a case in Tangshan, China

Thermal breakthrough is the main factor that affects the long-term efficiency of groundwater heat pump systems that predominantly for heating, particularly in northern China. A large water-source heat pump engineering project in Tangshan, China, is examined in this study. The project involves 18 pumping wells with a yield of 80 m3/h and 40 injection wells, covering a total planning area of 445,000 m2. In the third year, a groundwater monitoring system is installed in 23 wells to monitor the groundwater temperature. A hydrothermal coupling numerical model is established with the non-isothermal multiphase migration software TOUGH2. The model is analyzed by applying it to simulations. Simulation results are validated through a comparison with monitoring data. Results of the 10-year operation simulation show that the A3 and A4 well groups experience severe cold accumulation. Three optimization scenarios are thus presented to improve the groundwater temperature. Simulation results show that using the aquifer thermal energy storage method could fully meet the future requirements of heating during winter; however, the cost of this method is high. The optimization effect of alternating the pumping and the injection wells is insignificant. Adopting different pumping and injection layers can effectively control the water temperature decrease in the pumping wells; however, the breakthrough of cold plume should be prevented. The results of this study could provide a reference for the numerical prediction of large-scale water-source heat pump engineering projects in northern China.

Current Status of Groundwater Monitoring Networks in Korea

Korea has been operating groundwater monitoring systems since 1996 as the Groundwater Act enacted in 1994 enforces nationwide monitoring. Currently, there are six main groundwater monitoring networks operated by different government ministries with different purposes: National Groundwater Monitoring Network (NGMN), Groundwater Quality Monitoring Network (GQMN), Seawater Intrusion Monitoring Network (SIMN), Rural Groundwater Monitoring Network (RGMN), Subsidiary Groundwater Monitoring Network (SGMN), and Drinking Water Monitoring Network (DWMN). The Networks have a total of over 3500 monitoring wells and the majority of them are now equipped with automatic data loggers and remote terminal units. Most of the monitoring data are available to the public through internet websites. These Networks have provided scientific data for designing groundwater management plans and contributed to securing the groundwater resource particularly for recent prolonged drought seasons. Each Network, however, utilizes its own well-specifications, probes, and telecommunication protocols with minimal communication with other Networks, and thus duplicate installations of monitoring wells are not uncommon among different Networks. This mini-review introduces the current regulations and the Groundwater Monitoring Networks operated in Korea and provides some suggestions to improve the sustainability of the current groundwater monitoring system in Korea.

Post-closure care of engineered municipal solid waste landfills.

Post-closure care is divided into perpetual care (PPC) and long-term care (LTC). Guidelines for post-closure care and associated costs are important for engineered municipal solid waste (MSW) landfills. In many states in the USA, landfill owners are required to set aside funds for 30-40 years of LTC. Currently there are no guidelines for PPC, which is also required. We undertook a pilot study, using two landfills (note: average landfill capacity 2.5 million MT MSW waste) in Wisconsin, to establish an approach for estimating the LTC period using field data and PPC funding need. Statistical analysis of time versus concentration data of selected leachate parameters showed that the concentration of most parameters is expected to be at or below the preventive action limit of groundwater and leachate volume will be very low, within 40 years of the LTC period. The gas extraction system may need to be continued for more than 100 years. Due to lack of data no conclusion could be made regarding adequacy of the LTC period for the groundwater monitoring system. The final cover must be maintained for perpetuity. The pilot study shows that although technology is available, the financial liability of maintaining a 'Dry Tomb' design for landfills is significantly higher than commonly perceived. The paper will help landfill professionals to estimate realistic post-closure funding and to develop field-based policies for LTC and PPC of engineered MSW landfills.

Design and Implementation of the Power Watch Circuit of Groundwater Monitoring System

According to the characteristics of groundwater monitoring system,such as the field work unattended, replace the battery problem,the sampling time is short and standby time is long,the method is used to extend the power of life that using the watchcircuit control system under different power state automatic switching.Considering the characteristics of the system that parameter configuration commands are complex,field sampling is diverse and the communication time is not stable,thepaper puts forward the measuresthatmulti trigger source of hardware and status word of software collaborative work together to realize the system logic control.The overall power consumption of groundwater monitoring system which introduceswatch circuit is greatly reduced. Experimental results verify the feasibility of the watch circuit and show that the watch mode will become the development direction of field monitoring industry.

Remote Dynamic Monitoring System in Groundwater Engineering

In recent years, the exploitation and utilization of groundwater resources in the development of society plays a very important role. From the view of groundwater monitoring system, there are still a lot of problems, such as obsolete monitoring equipment, imperfect monitoring system. To solve these problems, by conducting studies of groundwater dynamic data acquisition and transfer of technology, research and development suited to China's national conditions groundwater monitoring series of instruments. Development of multi-level and multi-source remote management software base on network, build a set of groundwater dynamic data acquisition, storage, transmission, management, and remote control of the information service platform. It has been applied in a number of major projects for the construction and operation of the groundwater monitoring network in China to provide reliable monitoring equipment and management service software.

Study on the Present Situation and Development of Groundwater Monitoring Technology

In order to investigate the groundwater level and quality, and study the groundwater contaminant in vertical and the dynamics relation in different aquifers, the place of sampling and monitoring need to be installed in the relevant position of the aquifers to differentiate groundwater from different aquifers. In recent years, groundwater monitoring and sampling system has made great progress, this paper focuses on the current study and development of groundwater monitoring well technology, and analyses the development and the applied direction of monitoring well technology from single-well monitoring to multi-level monitoring, which would provide scientific references for domestic related and groundwater contaminant.

TFNM, ANN, ANFIS를 이용한 국가지하수관측망 지하수위 변동 예측 비교 연구

It is important to predict the groundwater level fluctuation for effective management of groundwater monitoring system and groundwater resources. In the present study, three different time series models for the prediction of groundwater level in response to rainfall were built, those are transfer function noise model (TFNM), artificial neural network (ANN), and adaptive neuro fuzzy interference system (ANFIS). The models were applied to time series data of Boen, Cheolsan, and Hongcheon stations in National Groundwater Monitoring Network. The result shows that the model performance of ANN and ANFIS was higher than that of TFNM for the present case study. As lead time increased, prediction accuracy decreased with underestimation of peak values. The performance of the three models at Boen station was worst especially for TFNM, where the correlation between rainfall and groundwater data was lowest and the groundwater extraction is expected on account of agricultural activities. The sensitivity analysis for the input structure showed that ANFIS was most sensitive to input data combinations. It is expected that the time series model approach and results of the present study are meaningful and useful for the effective management of monitoring stations and groundwater resources.