• International conference on construction engineering and project management
• /
• 2011.02a
• /
• pp.364-367
• /
• 2011

The levels of unemployment and poverty are extremely high and two of South Africa's most pressing problems. There is also a widely acknowledged need for housing and municipal infrastructure (water supply, sewerage, streets, storm water drainage, and electricity, refuse collection). From a theoretical perspective supported by experience elsewhere in Africa, there are reasons for considering that properly formulated employment creation programmes based on the use of labour-intensive methods could be established to construct and maintain the required physical infrastructure, thus creating employment, skills and institutional capacities. Over the past 30 years several projects have been initiated in South Africa to counter unemployment and poverty. Given the socio-economic conditions and political objectives (regarding development, employment creation and alleviation of poverty), it is anticipated that future large-scale construction projects will be proposed by the public sector (National, Provincial and Local Government). The paper will first examine the main tenets of the implementation of development projects through the use of labour-intensive construction and a description of progress elsewhere in Africa and their potential contribution which public works programmes could make to alleviate the poverty and unemployment problems. The research will then analyse the successes and challenges that have been experienced in South Africa in relation to the implementation of development projects over the past 30 years. The paper closes with recommendations and lessons for the future.

• Ecology and Resilient Infrastructure
• /
• v.6 no.2
• /
• pp.79-88
• /
• 2019

In order to study the water quality status and its causal environmental factors, the water quality variables of chemical oxygen demand (COD), chlorophyll a (Chl a), Total phosphorus (TP), and total nitrogen (TN), the hydrogeomorphologic variables of water level fluctuation, total water storage, dam elevation, watershed area, and shoreline development index, and the land cover variables of forest, agricultural area, and urbanized area in the watershed were investigated in total 73 reservoirs with various operational purposes, water level fluctuation and geographical distribution in South Korea. The water quality was more eutrophic in the reservoirs of the more urbanized and agricultural area in the watershed, the low altitude, the narrow water level fluctuation, the narrowed watershed area, and the more circular shape. In terms of the purposes of reservoir operation, the reservoirs for agricultural irrigation were more eutrophic than the reservoirs for flood control. The results of the variable selection and path analysis showed that COD determined by Chl a and TP was directly affected by water level fluctuation and the shoreline development of the reservoirs. TP was directly affected by the urbanized area of the watershed which was related to the elevation of the reservoir. TP was also influenced by the water level fluctuation and the shoreline development. In conclusion, the eutrophication of the reservoirs in Korea would be influenced by the land use of the watershed, hydrological and geographical characteristics of the reservoir, water level fluctuation by the anthropogenic management according to the reservoir operation purpose, and the location of the reservoirs.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.4
• /
• pp.332-337
• /
• 2023

Korea is not only surrounded by the sea on three sides, but also has national and local rivers extending 26,843 km, so it has a geographical feature in which abundant sea and inland water surface coexist. As the number of ships operating in the inland waters is continuously increasing due to the improvement of national income, the risk of ship accidents and human casualties in the inland waters is also increasing. In this study, a macroscopic plan for the safety management of inland water ships was presented through investigation of inland water related laws and operation status analysis. As an improvement plan, as a hardware infrastructure it is proposed to secure sufficient inland water fire-boats to secure the golden time for early response to accidents and lifesaving, and to operate an institution specializing in the prevention of inland water ships accidents. And as a software infrastructure, establish departure control standards for inland water ships and the safety diagnosis system currently applied only to sea going ships, the introduction of a system tailored to the characteristics of inland water ships. The proposed inland water safety management policy is expected to contribute to the preparation of prompt and systematic countermeasures in the event of an inland water ship accident, and it is hoped that it will serve as an opportunity to continue to pay attention to safety-related research on inland water ships, which was briefly activated after the sinking of M/V Sewol.

• Ecology and Resilient Infrastructure
• /
• v.4 no.1
• /
• pp.24-33
• /
• 2017

This study investigates the flow characteristics and bed changes with discharge using a two-dimensional numerical model, Nays2DH. The water depth at the outer part of curved channel is formed deeper from the narrow part after passing through the curved part. The point bar is developed in the wide section and water depth is shallow in the inside of the curved section. The flow is concentrated in the outer pater of the meandering section, which leads to the deep water. In the downstream section where the straight line formed, the flow is concentrated at the center of the bed. Alternating deep water and shallow places are generated due to the continuous formation of meandering. These characteristics are formed by the influence of strong two-stream flow in meandering stream. The dimensionless tractive force is also large in the region where the flow velocity is concentrated. However, in the narrow and sharp meandering river reaches, the pattern of bed changes and the spatial distribution patterns of flow velocity and dimensionless tractive force are inconsistent in the narrow and sharp meandered reaches due to the strong secondary flow.

• Ecology and Resilient Infrastructure
• /
• v.4 no.4
• /
• pp.216-225
• /
• 2017

We assessed the microhabitat conditions of three fish species (black shinner Pseudopungtungia nigra, striped shinner Pungtungia herzi, Korean shinner Coreoleuciscus splendidus) considering various stream order in the Geumgang River Basin. A total of 1,275 individuals were collected from 19 sites. And the microhabitat condition was assessed measuring flow velocity, water depth and substrate size at each site. The highest relative frequencies for P. herzi, C. splendidus and P. nigra were calculated 100% (n = 310), 78.9% (n = 784) and 47.3% (n = 181) respectively. P. herzi appeared in all streams, irrespective of their stream order; however, appearance in streams with the $2^{nd}$ order or lower was found to be scarcer than in the ones with the $3^{rd}$ order or higher. On the other hand, P. nigra and C. splendidus didn't appear in streams with the $2^{nd}$ order or lower. When it comes to P. nigra, the ones with 7 to 8 cm in length most frequently appeared. They inhabited streams, mainly, with 0.2 to $0.4m\;s^{-1}$ and 0.5 m in velocity and water depth, respectively. The three species all preferred runs as types of habitats with lots of coarse gravels-cobbles. P. herzi, the ones with 5 cm or shorter in length most frequently appeared. They inhabited streams, mainly, with 0 to $0.3m\;s^{-1}$ and 0.4 m in velocity and water depth, respectively. C. splendidus with 7 to 8 cm in length occupied the majority of them. They appeared in streams, mainly, with $0.9m\;s^{-1}$or higher and 0.3 m in velocity and water depth.

• Ecology and Resilient Infrastructure
• /
• v.6 no.1
• /
• pp.69-76
• /
• 2019

Ecosystem services are contributing to human welfare by enabling us to maintain our survival and quality of life. A metod of quantifying ecological functions is needed. We discussed the introduction and applications of ecosystem services to applied ecological engineering. The concept and assessment system of ecosystem services were applied to the economic valuation of river, the construction of blue-green-white network in urban area, ecological restoration, and integrated water management in Korea. The conceptual framework and assessment of ecosystem services can be used to promote value of ecological protection and restoration, helping stakeholders understand the benefits of ecosystems and increasing applications of the applied ecological engineering.

• Water Engineering Research
• /
• v.5 no.1
• /
• pp.17-36
• /
• 2004

This paper evaluated the water resources aspect of the operating results of the Daecheong Multipurpose Dam for the last 21 years. The elements that were evaluated included the amount of water supply from the dam. volume of outflow from the regulating dam, changes in the runoff volume at the dam site and downstream, and variations in the water supply capacity of the Daecheong Multipurpose Dam and the Geum River Barrage Dam situated in the estuary. The rainfall-runoff model was used to evaluate the changes in the runoff volume, and the water balance analysis system was used to evaluate the variations in the dams'water supply capacities. The volume of domestic and industrial water supply from the Daecheong Multipurpose Dam increased to 6.1 times for the last 21 years from 61${\times}$$10^6$$m^3$ in 1981 to 375${\times}$$10^6$$m^3$in 2001. The rate of outflow to inflow of the Daecheong Dam was analyzed 1.30 times in dry season, 1.12 times in semi-dry season, and 0.90 times in rainy season. The volume of inflow to the Geum River Barrage Dam down- stream after the dam's construction increased to 1.25 times in dry season and 1.02 times in semi-dry season and decreased to 0.94 times in rainy season. The water supply capacity of the estuary barrage dam almost did not change in cases with or without the Daecheong Multipurpose Dam, but storages were largely affected by the outflows of the Daecheong Multipurpose Dam.

• Environmental Engineering Research
• /
• v.22 no.1
• /
• pp.125-130
• /
• 2017

The Korean Ministry of Environment and Daegu Metropolitan City are establishing the Korea Water Cluster, which will focus on promoting and escalating Korean water industries. The water industry, a future-oriented and promising business sector, is continuously growing each year worldwide, so the project is very timely. In reality, however, challenges still need to be addressed, such as accessibility, logistics systems, social infrastructures, and attracting good companies. For the Korea Water Cluster to be successful, those issues should be solved, but it is difficult to untangle the matters only with efforts of the Korean Ministry of Environment and Daegu Metropolitan City since some issues will require a great deal of both money and time. Therefore, it is important for the Korean federal government to administer support and finances for certain parts of the project, and for the Korean Ministry of Environment and Daegu Metropolitan City to take on other issues to ensure the Korea Water Cluster is successful long-term. The success of the Korea Water Cluster project will result in the Korea Water Cluster becoming a global hub for the future water industries.

• Journal of Korean Society of Water and Wastewater
• /
• v.34 no.5
• /
• pp.357-371
• /
• 2020

Microplastics have become a rising issue in due to its detection in oceans, rivers, and tap water. Although a large number of studies have been conducted on the detection and quantification in various water bodies, the number of research conducted on the removal and treatment of microplastics are still comparatively low. In the current research, the inflow and removal of microplastics were investigated for various drinking water treatment plants around the world. Addition to the investigation of filed research, a survey was also conducted on the current research trend on microplastic removal for different treatment processes in the drinking water treatment plants. This includes the researches conducted on coagulation/flocculation, sedimentation, dissolved air flotation, sand filtration and disinfection processes. The survey indicated mechanisms of microplastic removal in each process followed by the removal characteristics under various conditions. Limitations of current researches were also mentioned, regarding the gap between the laboratory experimental conditions and field conditions of drinking water treatment plants. We hope that the current review will aid in the understanding of current research needs in the field of microplastic removal in drinking water treatment.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.162-162
• /
• 2019

Water Distribution Network (WDN) is a critical infrastructure to be maintained ensuring proper water supply to wide-spread consumers. The WDN consists of pipes, valves, pumps and tanks, and these elements interact each other to provide adequate system performance. If elements fail by internal or external interruptions, it may result in adverse impact to water service with different degree depending on the failed element. To determine an appropriate maintenance priority, the critical elements need to be identified and mapped in the network. In order to identify and prioritize the critical elements in WDN, an element-based simulation approach is proposed, in which all the elements composing the WDN are reviewed one at a time. The element-based criticality is measured using several resilience indexes that are newly developed in this study. The proposed resilience indexes are used to quantify the impacts of element failure to water service degradation. Here, three resilience indexes are developed, such as User Demand Severity, Economic Value Loss and Water Age Degradation, each of which intends to measure different aspects of consequences, such as social, economic, and water quality, respectively. For demonstration, the proposed approach is applied to a benchmark water network to identify and prioritize the critical elements.