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Augmenting water availability using water-harvesting structures is of importance in arid and semi-arid regions (ASARs). This paper provides an overview and examines challenges and prospects of the sand dam application in dry riverbeds of ASARs. The technology filters and protects water from contamination and evaporation with low to no maintenance cost. Sand dams improve the socio-economy of the community and help to cope with drought and climate change. However, success depends on the site selection, design, and construction. The ideal site for a sand dam is at a transition between mountains and plains, with no bend, intermediate slope, and impermeable riverbed in a catchment with a slope greater than 2°. The spillway dimensioning considers the flow velocity, sediment properties, and storage target, and the construction is in multi-stages. Recently, the failure of several sand dams because of incorrect siting, evaporation loss, and one-stage construction were reported. Revision of practitioners’ manuals by considering catchment scale hydrological and hydrogeological characteristics, spillway height, and sediment transport are recommended. Research shows that protected wells have better water quality than open wells and scoop holes. Therefore, the community should avoid open defecation, pit latrines, tethering of animals, and applying pesticides near the sand dam.
Bisrat Yifru; Min-Gyu Kim; Jeong-Woo Lee; Il-Hwan Kim; Sun-Woo Chang; Il-Moon Chung. Water Storage in Dry Riverbeds of Arid and Semi-Arid Regions: Overview, Challenges, and Prospects of Sand Dam Technology. Sustainability 2021, 13, 5905 .
AMA StyleBisrat Yifru, Min-Gyu Kim, Jeong-Woo Lee, Il-Hwan Kim, Sun-Woo Chang, Il-Moon Chung. Water Storage in Dry Riverbeds of Arid and Semi-Arid Regions: Overview, Challenges, and Prospects of Sand Dam Technology. Sustainability. 2021; 13 (11):5905.
Chicago/Turabian StyleBisrat Yifru; Min-Gyu Kim; Jeong-Woo Lee; Il-Hwan Kim; Sun-Woo Chang; Il-Moon Chung. 2021. "Water Storage in Dry Riverbeds of Arid and Semi-Arid Regions: Overview, Challenges, and Prospects of Sand Dam Technology." Sustainability 13, no. 11: 5905.
Numerical models are employed widely to evaluate the hydrological components of a watershed but, traditionally, watershed models simplify either surface or subsurface flow module. In this setup, as a bridge between groundwater and surface water regimes, aquifer recharge is the most affected segment of the water balance. Since the watershed processes are increasingly changed, the need for a comprehensive model with detailed conceptualizing capacity of both groundwater and surface water flow systems is growing. This work focuses on the spatiotemporal groundwater recharge assessment in gauged and ungauged agro-urban watersheds in South Korea using the updated SWAT-MODFLOW model, which integrates the Soil and Water Assessment Tool (SWAT2012) and Newton–Raphson formulation for Modular Finite Difference Groundwater Flow (MODFLOW-NWT) in a single executable code. Before coupling, the setup, calibration, and verification of each model were performed separately. After integration, irrigation pumps and drain cells mapping to SWAT auto-irrigation and subbasins were initiated. Automatic calibration techniques were used for SWAT and MODFLOW-NWT models, but a manual calibration was used for the integrated model. A physical similarity approach was applied to transfer parameters to the ungauged watershed. Statistical model performance indicators revealed that the low streamflow estimation was improved in SWAT-MODFLOW. The spatiotemporal aquifer recharge distribution from both the stream seepage and precipitation showed a substantial change, and most of the aquifer recharge occurs in July–September. The areal annual average recharge reaches about 18% of the precipitation. Low-lying areas receive higher recharge consistently throughout a year. Overall, SWAT-MODFLOW exhibited reasonable versatility in evaluating watershed processes and produced valuable results with reasonable accuracy. The results can be an important input for policymakers in the development of sustainable groundwater protection and abstraction strategies for the region.
Bisrat Yifru; Il-Moon Chung; Min-Gyu Kim; Sun Chang. Assessment of Groundwater Recharge in Agro-Urban Watersheds Using Integrated SWAT-MODFLOW Model. Sustainability 2020, 12, 6593 .
AMA StyleBisrat Yifru, Il-Moon Chung, Min-Gyu Kim, Sun Chang. Assessment of Groundwater Recharge in Agro-Urban Watersheds Using Integrated SWAT-MODFLOW Model. Sustainability. 2020; 12 (16):6593.
Chicago/Turabian StyleBisrat Yifru; Il-Moon Chung; Min-Gyu Kim; Sun Chang. 2020. "Assessment of Groundwater Recharge in Agro-Urban Watersheds Using Integrated SWAT-MODFLOW Model." Sustainability 12, no. 16: 6593.
Seawater intrusion (SWI) is a major environmental threat to groundwater resources in coastal regions. GALDIT is an index-based SWI vulnerability model that is increasingly being used in many parts of the world to identify regions that are vulnerable to various types of SWI based on six major parameters. In this study, we conducted a vulnerability assessment of Jeju Island to SWI based on several years of collected groundwater level data and hydrogeological values where the objectives of the study were to visualize the distribution of recent SWI, to increase the reliability of the GALDIT assessment method by improving current GALDIT techniques, and to respond effectively to diagnoses of SWI on Jeju. To improve the GALDIT assessment method to fit the Jeju model, the possibility of electrical conductivity was explored instead of standard GALDIT parameters that represented the existing impact of SWI. Improvements to the GALDIT vulnerability assessment method made it clear that groundwater became increasingly vulnerable to SWI in the existing high-vulnerability group. The results of this research may be used to develop a quantitative index for rational decision-making on policies and suggest the need for further improvements in groundwater management, with a stronger focus on easing groundwater use.
Sun Woo Chang; Il-Moon Chung; Min-Gyu Kim; Mesfin Tolera; Gi-Won Koh. Application of GALDIT in Assessing the Seawater Intrusion Vulnerability of Jeju Island, South Korea. Water 2019, 11, 1824 .
AMA StyleSun Woo Chang, Il-Moon Chung, Min-Gyu Kim, Mesfin Tolera, Gi-Won Koh. Application of GALDIT in Assessing the Seawater Intrusion Vulnerability of Jeju Island, South Korea. Water. 2019; 11 (9):1824.
Chicago/Turabian StyleSun Woo Chang; Il-Moon Chung; Min-Gyu Kim; Mesfin Tolera; Gi-Won Koh. 2019. "Application of GALDIT in Assessing the Seawater Intrusion Vulnerability of Jeju Island, South Korea." Water 11, no. 9: 1824.