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We examined different water management strategies for Taiqu Saltpan, which is part of the Qigu Saltpan Wetland complex in Tainan, Taiwan. The Taiqu saltpans are surrounded by artificial dikes, lack a water management plan, have insufficient water input during the dry season, and have little to no natural hydrologic connectivity to other wetlands in the Qigu Saltpan Wetland complex. Water is an important requirement for habitat and life. The need for a water management plan is crucial to enhance the existing ecosystem services. Besides the need to manage water, a robust stakeholder engagement plan was needed to better understand past practices and events and to develop a future saltpan management plan. Our aim was to bridge local stakeholder knowledge and scientific evidence into management strategies that could be used to improve waterflow between wetlands in the Qigu Saltpan Wetland complex with some soft modification of the existing infrastructure such as removing culverts, dikes, and dredging, and adapting the existing rules for gate operation without increasing the risk of flooding to the surround communities. Data were generated by merging field surveys (water gauge, velocity meter, and bird surveys) and aerial images to identify the saltpan hydrological dynamics before and after water gate operations in March and April 2020, respectively. Physical-inundation drainage modelling was used to calibrate, verify, and simulate four different management scenarios. Most of the water birds that use the Qigu Saltpan Wetland complex are from the Charadriidae and Scolopacidae families. Scenarios II and IV, which produced water depths that were suitable for members of the Charadriidae and Scolopacidae, are recommended. Implementation of water gate operations and stakeholder engagement would help in making decisions regarding future saltpan use in the face of uncertain challenges such as climate change. [ABSTRACT FROM AUTHOR]

The drainage gates have been controlled for desalination under normal conditions and flood defense in Saemangeum basin, Korea. Recently, it became an issue that the gates have been opened not to deteriorate water quality in the lake. It is, thus, necessary to precisely estimate the changes of water quality characteristics, especially DO, phosphate and nitrate, in the lake according to various gate operations. In this study, Semi-implicit Cross-scale Hydroscience Integrated System Model and Carbon, Silicate, Nitrogen Ecosystem model (SCHISM-CoSiNE) which is cable to simulate dynamic exchange such as gate operation conditions was utilized to obtain reliable and reasonable results including hydrodyanamic and environmental variables. For the verification, the measured data at 6 locations in Saemangeum basin was used to compare incluidng temperatue and salintiy from 2016 and each relative error became small enough to show high accurary. Also, under various scenarios by changing the designated water surface elevation on flood seasons, this model has been applied to present the best designated water surface elevation in terms of both water quality and water supply in the Saemangeum basin. It becomes possbile to show reliable guidance for dynamic operations and environmental changes with this model as requested in near future.

It has been widely known that crop cultivation in tidal lowland areas in the second crop (March-April) is not conducted by farmers in a maximum way. Thus, this research aims at investigating the dynamics of groundwater and its nutrient status condition for the purpose of supporting plant cultivation in the second crop after rice planting. The study was conducted in Banyu Urip Village, Tanjung Lago Telang II, Banyuasin. The plant used in this activity was paddy, with the treatment of a ratoon cultivation system. The ratoon system is paddy cultivation by using the first paddy planting season shoots. A urea treatment was given with a dose of 0 kg/ha (control) and a dose of 150 kg/ha. The results of soil analysis showed that, although not significant, there was an increase in the nutrient status of the soil condition. Therefore, it can be concluded that fertilizing was considered ineffective for the system of ratoon cultivation. The study of groundwater dynamics showed that at the early phase, a groundwater table was dropped above 30 cm (critical) but it could increase by the rain and water retention in the canal. The average of the groundwater table during the ratoon period was at the depth of 5-30 cm below the soil surface, allowing it to be suitable for plant growth. The plant growth at B treatment was better and its production was 2.8 ton/ha. This 2.8 ton/ha plant production was classified as a high category for paddy with the ratoon cultivation system. There is no effect of the fertilizer treatment on the nutrient status in the soil. Moreover, the application of fertilizer did not give a significant result on the production of rice.

The technology for closing port entrances using movable gates as a tsunami countermeasure has recently garnered increasing attention in Japan. However, it is not possible to mechanically operate the gates if power is lost because of a disaster. Accordingly, this study proposes a self-powered movable seawall system that utilizes microtidal energy generated by port closure for operating the gates. As tidal ranges in Japan are not favorable for power generation, the feasibility of the proposed system was assessed at 56 ports throughout Japan. The self-powered system was found feasible at nine ports during both spring and neap tide and at 14 ports during spring tide, whereas the tidal range was too small to operate the system at the other 33 ports. Moreover, 20 feasible ports were located such that tsunamis are predicted to occur in the scenario of a megathrust earthquake, which has a 90 % occurrence probability in the next 40 years. Surplus electricity is expected to be generated on-site with the proposed system, even if a power outage occurs, which is especially valuable for urgent disaster response and business continuity in industrial areas. Our findings outline a synergistic system between disaster prevention and the use of renewable energy. [ABSTRACT FROM AUTHOR]

In order to cover the crop water requirements, flow control structures such as gates and weirs are used to transfer the desired amount of water from the canals to the field canals. This paper examines the impact of gate operation and the selection of gates on the deposition of non-cohesive sediment. The Delft3D model is used to simulate the effects of different scenarios regarding gate operation and the location of the gate that is opened. The model results showed that the gate selection affects not only hydraulic parameters but also morphological parameters. It was found that opening the gates closer to the offtake resulted in less sediment deposition at the entrance of the branch canal when compared to opening the gates further away. Gate selection can be used as a tool in sediment management. By alternating the opening of different gates sediments that are already deposited after opening one gate can be eroded when another gate is operated, thus minimizing the additional cost of sediment removal. The use of Delft3D proved beneficial as the selection of different gates leads to asymmetric sediment deposition patterns which would be missed when using a 1D model.

This study examines an innovative Coastal Reservoir (CR) technique as a feasible solution for flood adaptation and mitigation in the Brisbane River Estuary (BRE), Australia, which is vulnerable to coastal flooding. The study analysed the operation of a CR by using the MIKE 21 hydrodynamic modelling package. The 2D hydrodynamic model was calibrated and validated for the 2013 and 2011 flood events respectively, with a Nash-Sutcliffe coefficient (Ens) between 0.87 to 0.97 at all gauges. River right branch widening and dredging produced a 0.16 m reduction in water level at the Brisbane city gauge. The results show that by suitable gate operation of CR, the 2011 flood normal observed level of 4.46 m, with reference to the Australian Height Datum (AHD) at Brisbane city, could have been reduced to 3.88 m AHD, while under the improved management operation of the Wivenhoe Dam, the flood level could be lowered to 4 m AHD at Brisbane city, which could have been reduced with CR to 2.87 m AHD with an overall water level reduction below the maximum flood level. The results demonstrated that the innovative use of a CR could considerably decrease the overall flood peak and lessen flood severity in the coastal city of Brisbane.

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Pump stations prevent backwater effects from urban streams and safely drain rainwater in urban areas. Urbanization has increased the required capacity of centralized reservoirs and drainage pumps; yet, their respective designs are based on the runoff of the target watershed at the time of design. In Korea, additional pump stations are constructed to supplement the insufficient capacity of centralized reservoirs and drainage pumps. Two pump stations in the same drainage area share centralized reservoirs, and there are gates between them. Operation of the gates and drainage pumps is based on the water level in the connected centralized reservoirs. The convertible operation is based on changes in flow between two pump stations with different effluent streams in shared centralized reservoirs. Efficient distribution of inflow to both pump stations provides additional storage capacity in centralized reservoirs and rapid drainage. For a rainfall event in 2010, flooding volumes for current and convertible operations were 58,750 and 7507 m³, respectively. For an event in 2011, the corresponding figures were 3697 and 471 m³. This shows that resilience increased by 0.10829 and 0.00756, respectively, for the two events. Accordingly, a new technique to operate multiple pump stations for reducing urban inundation is proposed. [ABSTRACT FROM AUTHOR]

During the flooding events, the operation of Chao Phraya Dam to control downstream water discharge is one of the causes of the inundation occuring over the upstream area. The purposes of this research are to study the effects of the operation of Chao Phraya Dam upon the upstream flood inundation and to find out the new measures of the flood mitigation in the upstream areas of Chao Phraya Dam by using a hydrodynamic model. The results show that Manning's n in the Chao Phraya River and its tributaries is 0.030-0.035 in the main channels and 0.050-0.070 in the flood plain areas. The backwater due to the operation of the Chao Praya dam affects as far as 110 kilometers upstream. New methods of water diversion can mitigate the flood inundation without the effect on the floating rice fields. The construction of reservoirs in the Upper Sakaekang River Basin and the Upper Yom River Basin will mitigate the flood not only in their own basins but also in the Lower Chao Phraya River Basin. The coordinated operation of the Chao Phraya Dam, the regulators and the upper basin reservoirs will efficiently mitigate the flood inundation.

Construction of river diversion barrages produces a shallow reservoir, called the pond, which is used more often for flow balancing between the inflows of the river and the outflows of the off-taking canal. However, deposition of sediment in the pond due to the relatively low velocities reduces the pond capacity. The current study investigates the effectiveness of gate operation and variations of other parameters in flushing out these sediment mounds, or shoals, from the barrage pond. Data from laboratory experiments on a scaled model of a prototype barrage is used to train and test different Artificial Neural Network (ANN) models of the system. The models map the relationship between flushing efficiency of a sediment shoal from the upstream of a barrage, and the parameters river discharge, barrage pond depth and area of gate opening, position of the sediment shoal with respect to the barrage. The ANN models are then used to study the effect of different parameters on the sediment flushing efficiency. Apart from river discharge and net area of gate opening, upstream pond depth is also found to have a significant effect on flushing efficiency, with a general trend of decrease in efficiency with increase in pond depth becoming apparent. Efficacy of different gate opening pattern is also tested, with the 'inverted arch' gate opening pattern proving to be the most efficient when compared with 'arch' and 'uniform' gate opening. [ABSTRACT FROM AUTHOR]

The Seonakdong River is an impound stream whose flowrate is controlled by the Daejeo and Noksan gates. Therefore, constant natural flow of the Seonakdong River does not occur. In contrast, pollutant loadings occur constantly occurring as water flows into the river from the watershed. The Daejeo gate is located at the upstream head and the Noksan gate is at the downstream end of the Seonakdong River. The Seonakdong River is an estuarine tributary of the Nakdong River. It is a reservoir-like river used for agricultural irrigation, with the Noksan gate at the river mouth serving to prevent the intrusion of saline water. In this study, a steadystate model, QUAL2E, and an unsteady-state model, CE-QUAL-RIV1, were chosen for comparative simulations. The results of the simulations of river water quality changes were verified with respect to short-term variations of water quality due to the increasing water flow from the Daejeo gate and the discharging flow from the Noksan gate. Field measurements were performed to monitor the flowrate and water quality during the operation of the Daejeo and Noksan gates in the Seonakdong River. The general trend observed is that the water quality worsens after the opening of the gates. The reduction in water quality ranges from 3% to 38%. These results show that the gate operators should carefully select the most appropriate operating plan to obtain better water quality in the Seonakdong River. The numerical simulation shows that a discharge of 300 CMS, which is a peak inflow from the Daejeo water gate to the river, can make it possible to achieve the target water quality of the Seonakdong River if the Daejeo water gate can remain open in connection with the Noksan water gate operation. [ABSTRACT FROM AUTHOR]

Abstract: This Letter proposes a theoretical scheme for scalable quantum computing with charge-phase qubits inside a common cavity. Individually addressing the applied gate pulses, we obtain the switchable interqubit couplings mediated by the cavity mode, from which a universal set of logic gates can be constructed. In our scheme the interqubit couplings are completely feasible to perform conditional gates, and the classical microwaves cause negligible leakage errors. [Copyright &y& Elsevier]

In this paper the measure of increased river base flow is developed and evaluated. Aim is the temporal increase of flow in manmade low flow stretches for sufficient dilution of downstream acute pollution introduced by combined sewer overflows (CSOs). The increase of flow is done by operating upstream located retaining structures such as hydropower intakes. For implementation both energy producers and municipalities are required to cooperate. Thus the measure fits into a core aim of the Water Framework Directive of having basin wide approaches for improvements. Technically the focus of the measure is clearly on the mitigation of acute pollution, not addressing delayed or accumulate pollutants. The framework and implications are discussed for having an appropriate real time control (RTC) concept based on model based predictive control (MBPC). A specially development algorithm for the operation is presented and subsequently tested off-line with a semi-virtual catchment. The boundary conditions of the catchment are varied with regard to the connected catchment size, the river connected and the pollutant concentration originating from the catchment. Based on these scenarios and a review on uncertainties in rain forecasts, limits for the measure are derived. Costs for the measure were estimated as equivalent cost due to losses in energy production. It is shown that not only the costs for annual spilled water are to be considered but as well peak flows generated in the river system. The increase of CSO volume as an alternative measure was not found to be a suitable measure, leading to unrealistic high volumes and consequently to exorbitant costs. [ABSTRACT FROM AUTHOR]

In river stretches being subjected to flow regulation, usually for the purpose of energy production (e.g. Hydropower) or flood protection (river barrage), a special measure can be taken against the effect of combined sewer overflows (CSOs). The basic idea is the temporal increase of the river base flow (during storm weather) as an in-stream measure for mitigation of CSO spilling. The focus is the mitigation of the negative effect of acute pollution of substances. The measure developed can be seen as an application of the classic real time control (RTC) concept onto the river system. Upstream gate operation is to be based on real time monitoring and forecasting of precipitation. The main objective is the development of a model based predictive control system for the gate operation, by modelling of the overall wastewater system (incl. the receiving water). The main emphasis is put on the operational strategy and the appropriate short-term forecast of spilling events. The potential of the measure is tested for the application of the operational strategy and its ecological and economic feasibility. The implementation of such an in-stream measure into the hydropower's operational scheme is unique. Advantages are (a) the additional in-stream dilution of acute pollutants entering the receiving water and (b) the resulting minimization of the required CSO storage volume. [ABSTRACT FROM AUTHOR]

All-optical switching characteristics of waveguide devices having a nonlinear distributed feedback structure are reported theoretically and experimentally. These devices were composed of a strip-loaded GaInAsP-InP waveguide and a Bragg reflector, which were suitable for optical integrated circuit. In the experiments, all-optical and gate operation and set-reset operation for two output ports were successfully demonstrated [ABSTRACT FROM PUBLISHER]

Yoo, H.J.; Kim, D.H.; Park, M.H., and Lee, S.O., 2021. Economic sediment transport control with sediment flushing curves for sea dike gate operation: Case study in Saemangeum Basin, Korea. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 161–165. Coconut Creek (Florida), ISSN 0749-0208. As the major reclamation works in Korea, the sea dikes have been installed for preventing the saltwater intrusion in Saemangeum Basin connected with Mangyeonggang and Dongjingang River, Korea since 2010. Recently, the sedimentation issues near the gates due to change of flow velocity might induce serious problems such as water pollution, local scour, stability of hydraulic structures linked with dike. We focused that the gate operation rule was changed to alleviate the sediment transport problem by altering the management water surface elevation in this study. The 3D numerical model, SCHISM, was used to simulate the sediment transport under the gate operation rule which was embedded after modifying the hydraulics structure module in SCHISM. The numerical model was verified by comparing with the measured data in the literature. It was found that the phenomenon induced by gate operation was accurately simulated to compare with the field measurements from Korea Rural Community Corporation (KRCC). Based on the results of SCHISM, the Best Management Practices on gate operation were examined and suggested the optimal solution in terms of structural stability and water use including water quality. [ABSTRACT FROM AUTHOR]

In order to cover the crop water requirements, flow control structures such as gates and weirs are used to transfer the desired amount of water from the canals to the field canals. This paper examines the impact of gate operation and the selection of gates on the deposition of non-cohesive sediment. The Delft3D model is used to simulate the effects of different scenarios regarding gate operation and the location of the gate that is opened. The model results showed that the gate selection affects not only hydraulic parameters but also morphological parameters. It was found that opening the gates closer to the offtake resulted in less sediment deposition at the entrance of the branch canal when compared to opening the gates further away. Gate selection can be used as a tool in sediment management. By alternating the opening of different gates sediments that are already deposited after opening one gate can be eroded when another gate is operated, thus minimizing the additional cost of sediment removal. The use of Delft3D proved beneficial as the selection of different gates leads to asymmetric sediment deposition patterns which would be missed when using a 1D model. [ABSTRACT FROM AUTHOR]

This study examines an innovative Coastal Reservoir (CR) technique as a feasible solution for flood adaptation and mitigation in the Brisbane River Estuary (BRE), Australia, which is vulnerable to coastal flooding. The study analysed the operation of a CR by using the MIKE 21 hydrodynamic modelling package. The 2D hydrodynamic model was calibrated and validated for the 2013 and 2011 flood events respectively, with a Nash-Sutcliffe coefficient (Ens) between 0.87 to 0.97 at all gauges. River right branch widening and dredging produced a 0.16 m reduction in water level at the Brisbane city gauge. The results show that by suitable gate operation of CR, the 2011 flood normal observed level of 4.46 m, with reference to the Australian Height Datum (AHD) at Brisbane city, could have been reduced to 3.88 m AHD, while under the improved management operation of the Wivenhoe Dam, the flood level could be lowered to 4 m AHD at Brisbane city, which could have been reduced with CR to 2.87 m AHD with an overall water level reduction below the maximum flood level. The results demonstrated that the innovative use of a CR could considerably decrease the overall flood peak and lessen flood severity in the coastal city of Brisbane. [ABSTRACT FROM AUTHOR]

Commercial salt pans around the world act as important habitats for waterbirds due to their unique trophic and physical attributes. Today, most commercial salt pans in Taiwan have been decommissioned and many have been designated as protected wetland habitats. Due to the dike and water gate systems controlling water flow in the salt pan wetlands, water management plans are important for habitat maintenance. Despite this, creation and implementation of habitat-oriented water management plans in protected salt pan wetlands is not common practice, especially in areas where flooding is a concern. In order to understand the potential for implementing water management plans for habitat creation in salt pan wetlands located in flood prone regions, this study designed and conducted three water management experiments for Budai Salt Pan Wetland, a wetland of national importance along the southwestern coast of Taiwan. The three experiments were designed to better understand the impacts of allowing water into the wetland during both the end and the beginning of the dry season in Taiwan. The design of each water gate operation was unique, based on the initial hydrologic conditions, and needs of the experiment in order to inform the design of future water management plans for the wetland. The consequent influence of gate operations on water depth, salinity, and immediate bird use of the wetland were analyzed. The experiments show that the water management techniques adopted in the study can allow for the creation of habitat types with varying water depths and salinity while not increasing flood risk to surrounding communities. Because the gate operation experiments were short term, a complete understanding of bird responses was limited. Even so, the responses of waterbird communities to these depth manipulations did indicate the potential of water management to increase foraging opportunities. The methods and findings of this research can inform wetland management and policy throughout Taiwan and the rest of the world. • Water gate operations can improve habitat for waterbirds in salt pan wetlands. • Depth manipulations give positive responses to increasing foraging opportunities for waterbids. • Gate operations should consider tide, flow, habitat needs, and flooding risk. [ABSTRACT FROM AUTHOR]

Sediments cause serious problems in irrigation systems, adversely affecting canal performance, driving up maintenance costs and, in extreme cases, threatening system sustainability. Multiple studies were done on the deposition of non-cohesive sediment and implications for canal design, the use of canal operation in handling sedimentation problems is relatively under-studied, particularly for cohesive sediments. In this manuscript, several scenarios regarding weirs and gate operation were tested, using the Delft3D model, applied to a case study from the Gezira scheme in Sudan. Findings show that weirs play a modest role in sedimentation patterns, where their location influences their effectiveness. On the contrary, gate operation plays a significant role in sedimentation patterns. Reduced gate openings may cause canal blockage while intermittently fully opening and closing of gates can reduce sediment deposition in the canal by 54% even under conditions of heavy sediment load. Proper location of weirs and proper adjusting of the branch canal's gate can substantially reduce sedimentation problems while ensuring sufficient water delivery to crops. The use of 2D/3D models provides useful insights into spatial and temporal patterns of deposition and erosion but has challenges related to running time imposing a rather coarse modelling resolution to keep running times acceptable. [ABSTRACT FROM AUTHOR]