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The impact of urbanization on the quality of drinking water sources is a challenge in many developing countries. In this research, the main source of drinking water was quantified, quality baseline defined, and a thematic decision support management tool developed to protect the quality using Aba, Nigeria. Data from primary and secondary sources were obtained from desktop search, empirical instruments, satellite data, hydrogeological investigations and water quality assessment. Geoscientific and statistical tools were used to analyse the landform, characterize the land use, and create management tools to protect the water source.
The results revealed that groundwater is the main source of water for both domestic and industrial uses. An average water consumption per capita rate of 35.9 l/day was estimated, which is low compared to the WHO recommendation. The landform and land-use analyses revealed that the area is low-lying, poorly drained, and the urban land-use is the fastest-growing class growing averagely at 0.6% /annum between 1986 to 2017. Some of the urban land-use practices that harm the quality of the groundwater were identified and mapped in a contamination hotspot map.
The results of the twenty-one quality indicators in the groundwater showed that the pH was acidic (3.7-5.6), total dissolved solids (TDS) ranged between 6.5 mg/l-364 mg/l. The mean concentrations of the remaining indicators were within the WHO limits for drinking water quality. But, the EC, TDS, chloride and nitrate revealed significant differences when tube-wells between densely and sparse built-up areas are compared. Again, four dominant water types were identified in groundwater. The Na-HCO3 water type was dominant mostly in the sparse built-up area and it is assumed as the background groundwater facies in the area. Whereas Mg, Ca-Cl, Na-Cl and Ca-HCO3 water types were predominant in the densely built-up area. The bacteriological assessments of drinking water from natural and alternative (i.e. beverages and packaged water) sources revealed the presence of E. Coli and Coliform bacteria in some samples of the natural water.
The groundwater quality distribution and vulnerability assessment maps were developed based on water quality index, and DRASTIC methodologies, respectively. The quality distribution map showed that > 98% of the area has a “suitable“ rating. While the vulnerability assessment map found that the groundwater has a “medium” baseline vulnerability covering about 80%. The differences in the results were due to some observed poor urban land-use practices in the area. Finally, a thematic decision support tool that delineates priority monitoring zones and suggests possible source protected areas tailored for the area was developed. This tool is cost-effective in protecting the groundwater quality and can be applied to other developing urban areas with similar physiological conditions.
Despite the continuous effects of natural hazards on cultural heritage and growing body of research on disaster risk assessment, cultural heritage still suffers from the lack of integrated risk assessment methodologies. Within the context of natural hazards, earthquakes need to be differently considered mainly due to the sudden massive destruction without warning and the unpredictability of the exact occurrence time and place. So far, limited sources have been adequately dedicated to developing risk assessment methodologies for cultural heritage. The challenge is to integrate the principles and methods of risk assessment in heritage conservation on one side, and to incorporate particular characteristics of cultural heritage and World Cultural Heritage properties (e.g. the Outstanding Universal Values and associated conditions of authenticity and integrity) into the risk assessment procedure, on the other.
There are numerous cultural properties that have been extremely affected by seismic events, such as the historic city of Bam in Iran. The World Heritage site of ‘Bam and its Cultural Landscape’, as a unique example of a traditional human settlement, is investigated in this research. Because Bam and its Cultural Landscape is located in a high-probability earthquake region and appeared to be highly vulnerable to seismic events, an integrated risk assessment for the property needs to be developed in response to potential earthquakes.
Recognising the challenge, a Cultural Heritage Risk Index for Bam is performed to measure the level of risk by aggregating the risk components, which are ‘hazard’ (earthquakes), ‘exposure’ (significance of the site elements), and ‘vulnerability’ (susceptibility and coping capacity). According to the risk index, an earthquake risk map is generated by applying Geographic Information System (GIS) to demonstrate a common understanding of the level of potential impacts on the property. Furthermore, a multiple impact identification matrix supports determining the potential impacts of an earthquake as well as its related secondary hazards and human-induced threats that need to be addressed in a risk preparedness plan.
The findings of the research emphasis that in addition to the hazard itself, diverse factors associated with the heritage significance, structural susceptibility, and institutional capacity highly influence the level of risk. The outputs of the risk assessment allows determining site-specific risk reduction strategies, particularly seismic susceptibility reduction and coping capacity building. This provides specialists and practitioners from multiple sectors engaged in the protection of (World) cultural heritage with a practical tool to facilitate risk communication and appropriate risk management planning.