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When pressed for time, outbreak investigators often use homogeneous mixing models to model infectious diseases in data-poor regions. But recent outbreaks such as the 2014 Ebola outbreak in West Africa have shown the limitations of this approach in an era of increasing urbanization and connectivity. Both outbreak detection and predictive modeling depend on realistic estimates of human and disease mobility, but these data are difficult to acquire in a timely manner. This is especially true when dealing with an emerging outbreak in an under-resourced nation. Weighted travel networks with realistic estimates for population flows are often proprietary, expensive, or nonexistent. Here we propose a method for rapidly generating a mobility model from open-source data. As an example, we use road and river network data, along with population estimates, to construct a realistic model of human movement between health zones in the Democratic Republic of the Congo (DRC). Using these mobility data, we then fit an epidemic model to real-world surveillance data from the recent Ebola outbreak in the Nord Kivu region of the DRC to illustrate a potential use of the generated mobility estimation. In addition to providing a way for rapid risk estimation, this approach brings together novel techniques to merge diverse GIS datasets that can then be used to address issues that pertain to public health and global health security.

In this work the major and trace elements pollution levels in groundwater of Tuticorin city of Tamil Nadu was investigated. This coastal city with numerous large and small scale industries has increasingly affected the water quality by dumping effluents. The mean major and trace elements levels in groundwater in descending order: Si > Sr > Zn > Fe > Rb > Se > Al > Mn > Cu > As > Cr > Ba > V > Ni > Pb > Mo > Co > Sb > Cd > Ag. The concentrations of As, Se, Pb, Ba, Al, Fe and V (0.084, 0.150, 0.057, 0.837, 0.357 and 0.052) in some of the groundwater samples exceed the standard value of world health organization (WHO, 2004). Interrelationship between the elements was done by correlation matrix and factor analysis which indicates the contribution from industrial and irrigation fields. Spatial interpolation of inverse distance method (IDW) maps of all the elements suggested that discharge of effluents from chemical factory (STERLITE, TAC, SPIC, HEAVY WATER PLANT, NILA SEA FOODS), municipal wastewater, fertilizers were added to the natural sources. Results of this research suggests that proper measures should be taken to protect the vital groundwater resources in the Tuticorin city. [ABSTRACT FROM AUTHOR]

We use electrical resistivity data arrayed in a 2715 km region with 30 locations to identify the saline water intrusion zone in part of Cauvery deltaic region, offshore Eastern India. From this dataset we are able to derive information on groundwater quality, thickness of aquifer zone, structural and stratigraphic conditions relevant to groundwater conditions, and permeability of aquifer systems. A total of 30 vertical electrode soundings (VES) were carried out by Schlumberger electrode arrangement to indicate complete lithology of this region using curve matching techniques. The electrical soundings exhibited that H and HK type curves were suitable for 16 shallow locations, and QH, KQ, K, KH, QQ, and HA curves were fit for other location. Low resistivity values suggested that saline water intrusion occurred in this region. According to final GIS map, most of the region was severely affected by seawater intrusion due to the use of over-exploitation of groundwater.The deteriorated groundwater resources in this coastal region should raise environmental and health concerns. [ABSTRACT FROM AUTHOR]

This research evaluated the groundwater quality of Thiruthuraipoondi city in the southern part of Tamil Nadu, India during summer and monsoon seasons in 2011. Eighteen groundwater samples were collected throughout Thiruthuraipoondi city and its surroundings. This case study represented that the combined analysis of ordinary kriging and CCME WQI in GIS was effective to evaluate the groundwater pollution sources, as well as for the spatial interpolation and assessment of groundwater quality. Groundwater samples evaluated by CCME WQI values belonged to good quality sectors in summer and monsoon, but to poor quality sectors at small patches of south and southeast directions in both seasons. Moreover, the higher concentration of Na and Cl was designated as irrigation waste and also seawater incursion. Based on the Piper plot, most of groundwater samples belong to Ca–Mg–Cl2type and followed by Ca–Cl2and Na–Cl types in summer season. In case of monsoon season, most of the groundwater samples dropped in Na–Cl type and followed by Ca–Mg–Cl2and Ca–Cl2water types. In Wilcox diagram, most of groundwater samples in both seasons occupied S2 and C4 categories of medium sodium hazard and very high salinity hazard, respectively. This research represented that higher concentration Na and Cl resulted from anthropogenic activities and seawater incursion due to overpumping of groundwater. An effective groundwater management plan of artificial recharge is necessary to conserve valuable groundwater resources in Thiruthuraipoondi city. [ABSTRACT FROM AUTHOR]

During the last three decades, remotely sensed data (both satellite images and aerial photographs) have been increasingly used in groundwater exploration and management exercises. An integrated approach has been adopted in the present study to delineate groundwater recharge potential zones using RS and GIS techniques. IRS-1C satellite imageries and Survey of India toposheets are used to prepare various thematic layers viz. geology, soil, land-use, slope, lineament and drainage. These layers were then transformed in to raster data using feature to raster converter tool in ArcGIS 9.3 software. The raster maps of these factors are allocated a fixed score and weight computed from Influencing Factor (IF) technique. The weights of factors contributing to the groundwater recharge are derived using aerial photos, geology maps, a land use database, and field verification. Subjective weights are assigned to the respective thematic layers and overlaid in GIS platform for the identification of potential groundwater recharge zones within the study area. Then these potential zones were categories as 'high', 'moderate', 'low', 'poor'. The resulted map shows that 19 % of the area has highest recharge potential, mainly confined to buried pediplain, agriculture land-use and river terraces (considerable amount of precipitated water percolates into subsurface), 28 % of the area has moderate groundwater recharge potentiality and rest of the area has low to poor recharge potentiality. The residual hills and linear ridges with steep slopes are not suitable for artificial recharge sites. Finally, 13 % of total average annual precipitated water (840 mm) percolates downward and ultimately contributes to recharge the aquifers in the Kovilpatti Municipality area. The paper is an attempt to suggest for maintaining the proper balance between the groundwater quantity and its exploitation. [ABSTRACT FROM AUTHOR]

This study evaluated groundwater quality of the coastal aquifer in Nagapattinam district with intensive agricultural activities in the southern part of India. Chemical components such as pH, EC, TDS, major cations and anions were used to identify seawater intrusion. Fifty-two groundwater samples were collected from dug and bore wells in this region during summer and monsoon seasons, 2011. EC, TDS, Na and Cl were higher in summer than in monsoon. The correlation and two-way-joining cluster analyses clearly show that groundwater quality is mainly controlled by seawater intrusion and other anthropogenic sources. Modified Hill-Piper exhibits that most of the samples belong to water contaminated with gypsum sector. The interpretation of Gibbs plot represents the groundwater samples that fall in evaporation and rock weathering zone, and other samples are affiliated to various anthropogenic activities. Based on Na %, SAR, chloride, hardness and Wilcox classification, the groundwater is moderately suitable for agriculture. This region is vulnerable to seawater intrusion during summer due to the severe pumping of groundwater. In groundwater quality maps produced by inverse distance weighting of ArcGIS, some good and medium patches could be used for agriculture to a certain extent. The northern, southern and central parts of the study area fell in poor quality regions because of seawater intrusion and infiltration of irrigation water contaminated with pesticides and fertilizers. [ABSTRACT FROM AUTHOR]