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Author Tamagnone, P.; Comino, E.; Rosso, M. url  openurl
  Title (down) Rainwater harvesting techniques as an adaptation strategy for flood mitigation Type Journal Article
  Year 2020 Publication Journal of Hydrology Abbreviated Journal  
  Volume 586 Issue Pages 124880  
  Keywords Rainwater harvesting techniques, Extreme rainfall, Runoff, Hydraulic modelling, Flood mitigation, Arid and semi-arid climate  
  Abstract The development of adaptation and mitigation strategies to tackle anthropic and climate changes impacts is becoming a priority in drought-prone areas. This study examines the capabilities of indigenous rainwater harvesting techniques (RWHT) to be used as a viable solution for flood mitigation. The study analyses the hydraulic performance of the most used micro-catchment RWHT in sub-Saharan regions, in terms of flow peak reduction (FPR) and volume reduction (VR) at the field and basin scale. Parametrized hyetographs were built to replicate the extreme precipitations that strike Sahelian countries during rainy seasons. 2D hydrodynamic simulations showed that half-moons placed with a staggered configuration (S-HM) have the best performances in reducing runoff. At the field scale, S-HM showed a remarkable FPR of 77% and a VR of 70% in case of extreme rainfall. Instead at the basin scale, in which only 5% of the surface was treated, 13% and 8% respectively for FPR and VR were obtained. In addition, the reduction of the runoff coefficient (Rc) between the different configuration was analyzed. The study critically evaluates hydraulic performances of the different techniques and shows how pitting practices cannot guarantee high performance in case of extreme precipitations. These results will enrich the knowledge of the hydraulic behavior of RWHT; aspect marginally investigated in the scientific literature. Moreover, this study presents the first scientific application of HEC-RAS as a rainfall-runoff model. Despite some limitations, this model has the effective feature of using very high-resolution topography as input for hydraulic simulations. The results presented in this study should encourage stakeholders to upscale the use of RWHT in order to lessen the flood hazard and land degradation that oppresses arid and semi-arid areas.  
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  Series Volume Series Issue Edition  
  ISSN 0022-1694 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ Tamagnone2020124880 Serial 240  
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Author Hdeib, R.; Aouad, M. url  openurl
  Title (down) Rainwater harvesting systems: An urban flood risk mitigation measure in arid areas Type Journal Article
  Year 2023 Publication Water Science and Engineering Abbreviated Journal  
  Volume 16 Issue 3 Pages 219-225  
  Keywords Rainwater harvesting, Urban floods, Flood map, Hydrodynamic model, Built environment, Arid areas  
  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.  
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  Series Volume Series Issue Edition  
  ISSN 1674-2370 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ Hdeib2023219 Serial 242  
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Author Jamali, B.; Bach, P.M.; Deletic, A. url  openurl
  Title (down) Rainwater harvesting for urban flood management – An integrated modelling framework Type Journal Article
  Year 2020 Publication Water Research Abbreviated Journal  
  Volume 171 Issue Pages 115372  
  Keywords Rainwater harvesting tanks, Urban flood simulation, Rapid flood inundation model, Urban flood risk mitigation  
  Abstract It is well known that rainwater harvesting (RWH) can augment water supply and reduce stormwater pollutant discharges. Due to the lack of continuous 2D modelling of urban flood coverage and its associated damage, the ability of RWH to reduce urban flood risks has not been fully evaluated. Literature suggests that small distributed storage spaces using RWH tanks will reduce flood damage only during small to medium flooding events and therefore cumulative assessment of their benefits is needed. In this study we developed a new integrated modelling framework that implements a semi-continuous simulation approach to investigate flood prevention and water supply benefits of RWH tanks. The framework includes a continuous mass balance simulation model that considers antecedent rainfall conditions and water demand/usage of tanks and predicts the available storage prior to each storm event. To do so, this model couples a rainfall-runoff tank storage model with a detailed stochastic end-use water demand model. The available storage capacity of tanks is then used as a boundary condition for the novel rapid flood simulation model. This flood model was developed by coupling the U.S. EPA Storm Water Management Model (SWMM) to the Cellular-Automata Fast Flood Evaluation (CA-ffé) model to predict the inundation depth caused by surcharges over the capacity of the drainage network. The stage-depth damage curves method was used to calculate time series of flood damage, which are then directly used for flood risk and cost-benefit analysis. The model was tested through a case study in Melbourne, using a recorded rainfall time series of 85 years (after validating the flood model against 1D-2D MIKE-FLOOD). Results showed that extensive implementation of RWH tanks in the study area is economically feasible and can reduce expected annual damage in the catchment by up to approximately 30 percent. Availability of storage space and temporal distribution of rainfall within an event were important factors affecting tank performance for flood reduction.  
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  Series Volume Series Issue Edition  
  ISSN 0043-1354 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ Jamali2020115372 Serial 239  
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Author Botha, R.; Lindsay, R.; Newman, R.T.; Maleka, P.P.; Chimba, G. url  openurl
  Title (down) Radon in groundwater baseline study prior to unconventional shale gas development and hydraulic fracturing in the Karoo Basin (South Africa) Type Journal Article
  Year 2019 Publication Applied Radiation and Isotopes Abbreviated Journal  
  Volume 147 Issue Pages 7-13  
  Keywords  
  Abstract The prospect of unconventional shale gas development in the semi-arid Karoo Basin (South Africa) has created the prerequisite to temporally characterise the natural radioactivity in associated groundwater which is solely depended on for drinking and agriculture purposes. Radon (222Rn) was the primary natural radionuclide of interest in this study; however, supplementary radium (226Ra and 228Ra) in-water measurements were also conducted. A total of 53 aquifers spanning three provinces were studied during three separate measurement campaigns from 2014 to 2016. The Karoo Basin’s natural radon-in-water levels can be characterised by a minimum of 1 ± 1 Bq/L (consistent with zero or below LLD), a maximum of 183 ± 18 Bq/L and mean of 41 ± 5 Bq/L. The mean radon-in-water levels for shallow aquifers were systematically higher (55 ± 10 Bq/L) compared to deep (14 ± 3 Bq/L) or mixed aquifers (20 ± 6 Bq/L). Radon-in-water activity concentration fluctuations were predominantly observed from shallow aquifers compared to the generally steady levels of deep aquifers. A collective seasonal mean radon-in-water levels increase from the winter of 2014 (44 ± 8 Bq/L) to winter of 2016 (61 ± 16 Bq/L) was noticed which could be related to the extreme national drought experienced in 2015. Radium-in-water (228Ra and 226Ra) levels ranged from below detection level to a maximum of 0.008 Bq/L (226Ra) and 0.015 Bq/L (228Ra). The 228Ra/226Ra ratio was characterised by a minimum of 0.93, a maximum of 6.5 and a mean value of 3.3 ± 1.3. Developing and improving baseline naturally occurring radionuclide groundwater databases is vital to study potential radiological environmental impacts attributed to industrial processes such as hydraulic fracturing or mining.  
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  Series Volume Series Issue Edition  
  ISSN 0969-8043 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ botha_radon_2019 Serial 169  
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Author Mathuthu, M.; Uushona, V.; Indongo, V. url  openurl
  Title (down) Radiological safety of groundwater around a uranium mine in Namibia Type Journal Article
  Year 2021 Publication Physics and Chemistry of the Earth, Parts A/B/C Abbreviated Journal  
  Volume 122 Issue Pages 102915  
  Keywords Groundwater, ICP-MS, Radiological hazard, Uranium mining  
  Abstract Uranium mining activities produce the main element used in nuclear energy production. However, it can also negatively affect the environment including groundwater by release of residues or effluent containing radioactive elements. The study investigated the concentration and radiological hazard of uranium in groundwater and seepage water from the tailings of a uranium mine in Namibia. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to assess the concentration of uranium in the groundwater and seepage water and the radiological hazards were determined. The radiological hazard indices Radium equivalent activity (Raeq), Absorbed dose (D), Annual Effective Dose equivalent (AEDE), External hazard index (Hex) and Internal hazard index (Hin) were determined and compared to limits recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The calculated average value of D and Hin of groundwater is 108.11nGyh−1 and 1.26, respectively and are above the UNSCEAR values (55 nGyh−1 and 1). Further, the average values of Raeq, AEDE and Hex were below the recommended values. The isotopic ratio of uranium radionuclides in groundwater indicates that the uranium in the sampled groundwater is below 1 suggesting it is not natural uranium present but a possible contamination from the mine seepage. The radiological hazard parameters of the seepage water were above the recommended values and thus pose a radiation risk to human and environment.  
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  Series Volume Series Issue Edition  
  ISSN 1474-7065 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ mathuthu_radiological_2021 Serial 160  
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