Analysis on influencing factors and simulation of sediment release by density current: the case of Xiaolangdi Reservoir

Density current venting by bottom outlets is the main form of sediment release from large reservoirs during sediment retention periods. Taking Xiaolangdi Reservoir as a case study, this study analyzed influencing factors of sediment release by density currents and proposed a semi-empirical formula to simulate the density current release process. The results show that the amount of incoming water and sediment, length of backwater, and sedimentation volume upstream of backwater zones are the main factors influencing sediment discharge. However, the importance of influencing factors varies slightly for different sediment supply areas. The semi-empirical formula provides a good simulation of the actual sediment release process under a relatively stable water level, and thus, it can extend scientific and technical support necessary for reservoir operation

Variation on sandbar of tributary in Xiaolangdi Reservoir on Yellow River, China

Sandbar development would stop the water and sediment exchange between main river and tributary and even influence the normal reservoir opeartion. From the surveyed data of reservoir built many years ago, it shows that when there is a bar in tributary mouth, the tributary volume below the bar will become nullification during the period of flood control or water and sediment regulation of reservoir. There are more tributaries in Xiaolangdi reservoir than the others that it occupies 41.3% of the total initial volume of tributary volume. Obviously, the effective use of tributary volume has been important influenced by comprehensive utilization efficiency of reservoir scheduling, such as flood control, sedimentation reduction and comprehensive utilization. Results of Xiaolangdi Reservoir mobile-bed physical model experiments show that tributary is equivalent to lateral extension of river bed, the tributary intrusion deposition process have strongly relations with the factors, such as original topography, river bed deposition shape and its regime, process with input discharge and input sediment, and method of reservoir regulation. The variation trends of main river and tributary terrain forecasted by model test are basically in accordance with field surveyed data. The results could be used for research, design, and forecasting of reservoirs in sediment-laden river

Variation on sandbar of tributary in Xiaolangdi Reservoir on Yellow River, China

Sandbar development would stop the water and sediment exchange between main river and tributary and even influence the normal reservoir opeartion. From the surveyed data of reservoir built many years ago, it shows that when there is a bar in tributary mouth, the tributary volume below the bar will become nullification during the period of flood control or water and sediment regulation of reservoir. There are more tributaries in Xiaolangdi reservoir than the others that it occupies 41.3% of the total initial volume of tributary volume. Obviously, the effective use of tributary volume has been important influenced by comprehensive utilization efficiency of reservoir scheduling, such as flood control, sedimentation reduction and comprehensive utilization. Results of Xiaolangdi Reservoir mobile-bed physical model experiments show that tributary is equivalent to lateral extension of river bed, the tributary intrusion deposition process have strongly relations with the factors, such as original topography, river bed deposition shape and its regime, process with input discharge and input sediment, and method of reservoir regulation. The variation trends of main river and tributary terrain forecasted by model test are basically in accordance with field surveyed data. The results could be used for research, design, and forecasting of reservoirs in sediment-laden river

The New Buffer Salt-Protected Sodium Butyrate Promotes Growth Performance by Improving Intestinal Histomorphology, Barrier Function, Antioxidative Capacity, and Microbiota Community of Broilers

In this study, a commercial sodium butyrate protected by a new buffer salt solution (NSB) was tested to determine whether it can be used as an antibiotic alternative in broiler production. A total of 192 1-day-old broilers were randomly allocated to three dietary treatments: soybean meal diet (CON), antibiotic diet (ANT, basal diet + 100 mg/kg aureomycin), and NSB (basal diet + 800 mg/kg NSB). The growth performance, serum anti-inflammatory cytokines, intestinal morphology, gut barrier function, antioxidative parameters, SCFAs’ content, and cecal microbiota were analyzed. The result showed that NSB significantly improved ADFI and ADG (p p p p p p p p p p p p p p p p p > 0.05) in alpha and beta diversity among the groups. LEFSe analysis also indicated that Peptostreptococcaceae, Colidextribacter, Firmicutes, Oscillospira, and Erysipelatoclostridiaceae, which promote SCFA production (p Colidextribacter with ADFI, ADG, VH, claudin-1 (p unclassified_f__Peptostreptococcaceae with ADFI, IL-10, and ZO-1 were positively correlated (p p p < 0.05), showed a positive correlation. In conclusion, NSB enhanced the growth performance by improving jejunum and ileum morphology, and serum anti-inflammatory cytokines, and by regulating the intestinal barrier function and antioxidant capacity, SCFAs’ content, and cecum microbiota, showing its potential use as an alternative to antibiotics in poultry nutrition