Contamination

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Modular neural networks to predict the nitrate distribution in ground water using the on-ground nitrogen loading and recharge data

Journal Title, Volume, Page: 
Environmental Modelling and Software (20): 851–871. doi:10.1016/j.envsoft.2004.05.001
Year of Publication: 
2005
Authors: 
Mohammad N. Almasri
Department of Civil and Environmental Engineering and Utah Water Research Laboratory, Utah State University, Logan, UT 84322-8200, USA
Current Affiliation: 
Department of Civil Engineering, College of Engineering, An-Najah National University, P. O. Box 7, Nablus, Palestine
Jagath J. Kaluarachchi
Department of Civil and Environmental Engineering and Utah Water Research Laboratory, Utah State University, Logan, UT 84322-8200, USA
Preferred Abstract (Original): 
Artificial neural networks have proven to be an attractive mathematical tool to represent complex relationships in many branches of hydrology. Due to this attractive feature, neural networks are increasingly being applied in subsurface modeling where intricate physical processes and lack of detailed field data prevail. In this paper, a methodology using modular neural networks (MNN) is proposed to simulate the nitrate concentrations in an agriculture-dominated aquifer. The methodology relies on geographic information system (GIS) tools in the preparation and processing of the MNN input–output data. The basic premise followed in developing the MNN input–output response patterns is to designate the optimal radius of a specified circular-buffered zone centered by the nitrate receptor so that the input parameters at the upgradient areas correlate with nitrate concentrations in ground water. A three-step approach that integrates the on-ground nitrogen loadings, soil nitrogen dynamics, and fate and transport in ground water is described and the critical parameters to predict nitrate concentration using MNN are selected. The sensitivity of MNN performance to different MNN architecture is assessed. The applicability of MNN is considered for the Sumas-Blaine aquifer of Washington State using two scenarios corresponding to current land use practices and a proposed protection alternative. The results of MNN are further analyzed and compared to those obtained from a physically-based fate and transport model to evaluate the overall applicability of MNN.
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Nitrate Contamination Of Groundwater: A Conceptual Management Framework

Journal Title, Volume, Page: 
Environmental Impact Assessment Review 27 (2007) 220–242
Year of Publication: 
2007
Authors: 
Mohammad N. Almasri
Water and Environmental Studies Institute, An-Najah National University, Nablus, Palestine
Current Affiliation: 
Department of Civil Engineering, An-Najah National University, Palestine
Preferred Abstract (Original): 
In many countries, public concern over the deterioration of groundwater quality from nitrate contamination has grown significantly in recent years. This concern has focused increasingly on anthropogenic sources as the potential cause of the problem. Evidence indicates that the nitrate (NO3) levels routinely exceed the maximum contaminant level (MCL) of 10 mg/l NO3-N in many aquifer systems that underlie agriculture-dominated watersheds. Degradation of groundwater quality due to nitrate pollution along with the increasing demand for potable water has motivated the adoption of restoration actions of the contaminated aquifers. Restoration efforts have intensified the dire need for developing protection alternatives and management options such that the ultimate nitrate concentrations at the critical receptors are below the MCL. This paper presents a general conceptual framework for the management of groundwater contamination from nitrate. The management framework utilizes models of nitrate fate and transport in the unsaturated and saturated zones to simulate nitrate concentration at the critical receptors. To study the impact of different management options considering both environmental and economic aspects, the proposed framework incorporates a component of a multi-criteria decision analysis. To enhance spatiality in model development along with the management options, the utilization of a land use map is depicted for the allocation and computation of on-ground nitrogen loadings from the different sources.
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Modeling nitrate contamination of groundwater in agricultural watersheds

Journal Title, Volume, Page: 
Journal of Hydrology (2007) 343, 211– 229
Year of Publication: 
2007
Authors: 
Mohammad N. Almasri
Water and Environmental Studies Institute, An-Najah National University, P.O. Box 7, Nablus, Palestine
Current Affiliation: 
Department of Civil Engineering, An-Najah National University, Palestine
Jagath J. Kaluarachchi
Department of Civil and Environmental Engineering, Utah Water Research Laboratory, Utah State University, Logan, Utah 84321-8200, USA
Preferred Abstract (Original): 
This paper presents and implements a framework for modeling the impact of land use practices and protection alternatives on nitrate pollution of groundwater in agricultural watersheds. The framework utilizes the national land cover database (NLCD) of the United State Geological Survey (USGS) grid and a geographic information system (GIS) to account for the spatial distribution of on-ground nitrogen sources and corresponding loadings. The framework employs a soil nitrogen dynamic model to estimate nitrate leaching to groundwater. These estimates were used in developing a groundwater nitrate fate and transport model. The framework considers both point and non-point sources of nitrogen across different land use classes. The methodology was applied for the Sumas–Blaine aquifer of Washington State, US, where heavy dairy industry and berry plantations are concentrated. Simulations were carried out using the developed framework to evaluate the overall impacts of current land use practices and the efficiency of proposed protection alternatives on nitrate pollution in the aquifer.
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Trends And Occurrences of Nitrate In The Groundwater of The West Bank, Palestine

Journal Title, Volume, Page: 
Applied Geography Volume 29, Issue 4, December 2009, Pages 588-601
Year of Publication: 
2009
Authors: 
Fathi M. Anayah
Utah Water Research Laboratory, Civil and Environmental Engineering, Utah State University, Logan, UT 84321, USA
Mohammad N. Almasri
College of Engineering, Department of Civil Engineering, An-Najah National University, P.O. Box 7, Nablus, West Bank, Palestine
Current Affiliation: 
Department of Civil Engineering, An-Najah National University, Palestine
Preferred Abstract (Original): 

Groundwater is the major source of water to the Palestinians. Efficient management of this resource requires a good understanding of its status. This understanding necessitates a characterization of the quality of the utilizable volumes. This paper focuses on the assessment of nitrate concentrations in the aquifers of the West Bank, Palestine. A preliminary statistical analysis is carried out for the spatial and temporal distributions of the nitrate concentrations. GIS is utilized to facilitate the analysis and to efficiently account for the spatiality of nitrate concentrations. The analysis was carried out at different spatial levels and key parameters including soil type, watersheds, depth, population, and rainfall. It is observed that elevated nitrate concentrations in the groundwater greatly coincide with increasing rainfall, particularly in the last few years. Results confirm that the annual mean nitrate concentration in the Western groundwater basin has an increasing trend over the period from 1982 to 2004 indicating its vulnerability to contamination. This result can be attributed to the agricultural activities along with the high groundwater recharge. However, leaking septic and sewer systems are considerably causing nitrate contamination of groundwater in populated areas. Overall, the recommendations call for an immediate intervention to manage the quality problems in the West Bank aquifers.

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Assessment Of Nitrate Contamination Of Groundwater Using Lumped-Parameter Models

Journal Title, Volume, Page: 
Environmental Modelling & Software 24 (2009) 1073–1087
Year of Publication: 
2009
Authors: 
Lubna Hajhamad
College of Engineering, Department of Civil Engineering, An-Najah National University, P.O. Box 7, Nablus, Palestine
Mohammad N. Almasri
College of Engineering, Department of Civil Engineering, An-Najah National University, P.O. Box 7, Nablus, Palestine
Current Affiliation: 
Department of Civil Engineering, An-Najah National University, Palestine
Preferred Abstract (Original): 

In this paper, lumped-parameter models (LPMs) were developed and utilized to simulate nitrate concentration in the groundwater of Gaza City and Jabalia Camp (GCJC) in the Gaza Coastal Aquifer (GCA) in Palestine. In the GCJC area, nitrate levels exceed the maximum contaminant level (MCL) of 10 mg/L NO3-N (45 mg/L NO3) in many wells. Elevated nitrate concentrations in the groundwater of GCJC area are due to the disposal of untreated wastewater, the existence of heavy agriculture in the surrounding areas, and the use of cesspits for wastewater disposal. The developed LPMs utilize monthly time steps and take into consideration all the sources and sinks of water and nitrate in the study area. The main outcomes of the LPMs are the average temporal water table elevation and nitrate concentration. In order to demonstrate LPMs usability, a set of management options to reduce nitrate concentration in the groundwater of the study area were proposed and evaluated using the developed LPMs. Four broad management options were considered where these options tackle the reduction of nitrate concentration in the lateral inflow, rehabilitation of the wastewater collection system, reduction in cesspit usage, and the restriction on the use of nitrogen-based fertilizers. In addition, management options that encompass different combinations of the single management options were taken into account. Different scenarios that correspond to the different management options were investigated. It was found based on the LPMs that individual management options were not effective in meeting the MCL of nitrate. However, the combination of the four single management options with full rehabilitation and coverage of the wastewater collection network along with at least 60% reduction in both nitrate concentration in the lateral inflow and the use of nitrogen-based fertilizers would meet the MCL constraint by the end of the management period.

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