Abstract: Rainwater harvesting (RWH) systems have been developed to compensate for shortage in the water supply worldwide. Such systems are not very common in arid areas, particularly in the Gulf Region, due to the scarcity of rainfall and their reduced efficiency in covering water demand and reducing water consumption rates. In spite of this, RWH systems have the potential to reduce urban flood risks, particularly in densely populated areas. This study aimed to assess the potential use of RWH systems as urban flood mitigation measures in arid areas. Their utility in the retention of stormwater runoff and the reduction of water depth and extent were evaluated. The study was conducted in a residential area in Bahrain that experienced waterlogging after heavy rainfall events. The water demand patterns of housing units were analyzed, and the daily water balance for RWH tanks was evaluated. The effect of the implementation of RWH systems on the flood volume was evaluated with a two-dimensional hydrodynamic model. Flood simulations were conducted in several rainfall scenarios with different probabilities of occurrence. The results showed significant reductions in the flood depth and flood extent, but these effects were highly dependent on the rainfall intensity of the event. RWH systems are effective flood mitigation measures, particularly in urban arid regions short of proper stormwater control infrastructure, and they enhance the resilience of the built environment to urban floods.

Abstract: Abnormally high uranium (U) prevalence in groundwater is a neoteric subject of concern throughout the world because of its direct impact on human health and well-being. Groundwater is used as the most preferred choice for drinking because of its good quality and ease of availability in rural and urban parts of India, and also in different parts of the world. India is an agriculture-dominant country and its 50–80% irrigational requirement is met by groundwater, besides this nearly 90% of rural and 50% of urban water needs are fulfilled by groundwater. The uranium concentration in groundwater in different parts of India namely Punjab, Haryana, Rajasthan, Madhya Pradesh, Karnataka, etc. found to be varying from 0 mg/L to 1443 mg/L, and in different parts of the world, it is found up to 1400 mg/L in the countries like United States, Canada, Finland, Mongolia, Nigeria, South Korea, Pakistan, Burundi, China, Afghanistan, etc. Various natural factors such as geology, hydro-geochemistry, and prevailing conditions as well as anthropogenic factors including mining, nuclear activities, erratic use of fertilizers, and overexploitation of groundwater resources are responsible for adding uranium in groundwater. Groundwater is considered a primary source of uranium ingestion in human beings as it contributes 85% while food contributes 15%. Uranium affects living beings as a two-way sword, being a radioactive element, causing radiotoxicity, and on the other hand as a heavy metal, it causes chemotoxicity. The main target organs affected by the consumption of uranium-contaminated water are kidneys, bones, lungs, etc. It can cause renal failure, impair cell functioning and bone growth, and mutation in DNA. Although, its toxic effects, being a heavy metal, are more severe than its radiotoxicity. Various techniques are available for the efficient removal of uranium from the groundwater such as bioremediation, nanotechnology-enhanced remediation, adsorption, filtration, etc. This chapter entails a comprehensive investigation of uranium contamination in groundwater of rural and urban parts of India their probable sources, health impacts, treatment, and mitigation techniques available to manage groundwater resources.

Abstract: Since the coming into force of the European Council Directive 51/2013 EURATOM and its transposition into the Spanish legislation, the presence of radioactive substances in drinking waters must be kept under surveillance to ensure that the health protection requirements are met. Driven by this regulatory framework, in an attempt to know the starting point from which to design surveillance plans, the groundwaters intended for human consumption of Castilla y León (Spain) have been radiologically characterised by using both low-level γ-ray and α-particle spectrometry to determine the activity concentration of the natural radionuclides needed to account for the indicative dose estimation. This extensive research has comprised the radiological characterisation of more than 400 drinking water samples from one of the European Union’s largest regions. Furthermore, the gross α and gross β activities have been analysed. Results showed a high geographical variability that can be related to the hydrogeological formations where the groundwaters come from. The uranium isotopes, 234U and 238U, are the main radionuclides present in the analysed drinking waters reaching values up to 2000 mBq/L, in the southwestern and western of Castilla y León, where U-rich minerals are part of the host rock. High 210Pb and 226,228Ra occurrences are found in the low permeability igneous and metasedimentary hydrogeological formations of Salamanca province. From a public health protection point of view, 4.4% of the total drinking water samples from intakes exceeded the Indicative Dose parametric value of 0.1 mSv, which is a not negligible number of samples, being very likely related to granitic and metamorphosed host rock under specific local conditions. This fact highlights the need for research and consideration of special surveillance of the groundwaters from these areas.