return flows
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2022 ◽  
Vol 34 (3) ◽  
pp. 0-0

Based on rural population return management, governance theory, and information technology theory, this paper analyzes the specific performance of rural areas in managing population return, and describes the overview, quantity, life status, and demographic characteristics of rural population return, as well as the current situation of rural population return management. A method of managing rural population return based on a rural population return management model constructed by a machine learning algorithm is designed. The empirical results show that the method designed in this paper is low-cost, fast, and highly accurate, and is well suited for improving and expanding the system for managing rural return flows. The research in this paper provides a reference for further promoting the transformation strategy of rural governance in the context of new urbanization.


Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1366
Author(s):  
Glen R. Walker ◽  
Avril C. Horne ◽  
Quan J. Wang ◽  
Rob Rendell

Improving irrigation efficiency (IE) is an approach used globally to help meet competing demands for water and facilitate reallocation of water between sectors. In the Murray–Darling Basin in Australia, the Australian government has invested heavily in IE projects to recover water for the environment. However, this approach has been seriously questioned, out of concerns that improved IE would reduce irrigation return flows to rivers and therefore offset water recovery. In this study, we use a water balance model to assess the impact of the IE projects on return flows and highlight sensitivities and uncertainties. The model enables the impact on return flows to be assessed on specific IE projects and regional characteristics. Overall, reductions in return flows are estimated to be less than 20% of the total proposed IE savings. The history of IE in the southern MDB has meant that most of the current reductions are in ground return flows. Our estimate is much lower than two previous studies, mainly due to different assumptions being used on groundwater connectivity between irrigation areas and major streams. While the IE projects significantly reduce seepage to groundwater (with off-farm and on-farm projects reducing seepage by 19% and 53% of total savings respectively), not all seepage reductions will translate to a reduction in ground return flows to rivers. A lower estimate is consistent with existing monitoring and groundwater modeling studies. In this paper, the study results are discussed in a broader context of impacts of IE projects on volumes and salinity of streams and groundwater resources.


2021 ◽  
Vol 12 ◽  
Author(s):  
Robert S. Dungan ◽  
David L. Bjorneberg

Irrigation return flows (IRFs) collect surface runoff and subsurface drainage, causing them to have elevated contaminant and bacterial levels, and making them a potential source of pollutants. The purpose of this study was to determine antimicrobial susceptibility among Escherichia coli and enterococcal isolates that were collected from IRFs in a south-central Idaho watershed. Environmental isolates can be a potentially important source of antimicrobial resistance (AMR) and IRFs may be one way resistance genes are transported out of agroecosystems. Water samples were collected from nine IRFs and one background site (canal water from Snake River) on a biweekly basis during 2018. Escherichia coli and enterococci were enumerated via a most probable number (MPN) technique, then subsamples were plated on selective media to obtain isolates. Isolates of E. coli (187) or enterococci (185) were tested for antimicrobial susceptibility using Sensititre broth microdilution plates. For E. coli, 13% (25/187) of isolates were resistant to tetracycline, with fewer numbers being resistant to 13 other antimicrobials, with none resistant to gentamicin. While 75% (141/187) of the E. coli isolates were pan-susceptible, 12 multidrug resistance (MDR) patterns with 17 isolates exhibiting resistance to up to seven drug classes (10 antimicrobials). For the enterococcal species, only 9% (16/185) of isolates were pan-susceptible and the single highest resistance was to lincomycin (138/185; 75%) followed by nitrofurantoin (56/185; 30%) and quinupristin/dalfopristin (34/185; 18%). In addition, 13 enterococcal isolates belonging to Enterococcus faecalis, Enterococcus faecium, Enterococcus casseliflavus, and Enterococcus thailandicus, were determined to be MDR to up to six different antimicrobial drug classes. None of the enterococcal isolates were resistant to gentamycin, linezolid, tigecycline, and vancomycin.


2021 ◽  
Vol 4 (198) ◽  
pp. 24-31
Author(s):  
R.M. Beysenbaev ◽  

The current market environment of retail trade enterprises indicates the need for accounting and management of reverse logistics, regardless of the size of the retailer. In 2020, only in the United States, retailers' losses from product returns amounted to about 400 billion dollars. More liberal return policies and a growing online sales market lead to more returned products and an increase in the volume of losses from returns, and it seems possible to believe that these trends will continue in the coming years, which indicates the need for retailers to have a way to assess the economical effectiveness of their systematic interaction with return flows in order to make management decisions on an objective and reliable information basis.


Author(s):  
Arash Ebadi ◽  
Omid Raja ◽  
Hamed Ebrahimian ◽  
Mohammad Reza Yazdani ◽  
Vahid Rezaverdinejad

One of the common irrigation systems in the paddy fields is field-to-field irrigation. The management of these irrigation systems is difficult and essential because of the water scarcity. Estimating the parameters affecting the water balance in paddy fields is necessary by considering the irrigation requirements of downstream fields. The objective of this study is to develop a computational model for calculating the water balance components including the irrigation return flows in paddy fields. The irrigation return flow is considered the main factor of water supply in downstream fields. The developed model is able to calculate the crop evapotranspiration, deep percolation, surface water storage, soil moisture, irrigation return flow, and irrigation efficiency. Field data including the outflow discharge and ponding water depth from the paddy fields during the growing season was used to evaluate the model. Five fields were investigated, which the upstream field was being irrigated continuously, and the return flows were transferred into the downstream fields. The model’s water balance error was about 0.5 %. The Root Mean Square Error (RMSE), Nash-Sutcliffe Efficiency (NSE), and coefficient of determination (R2) for simulation of outflow discharge were 0.124 L/s, 0.827, and 0.893, respectively. These indices were 9.6 mm, 0.884, and 0.909 for simulation of ponding water depth on paddy fields, respectively. The results showed that the model performed well to simulate outflow discharge and ponding water depth. Hence, the management of the water balance components in paddy fields would be much easier through the modelling water flow to increase the irrigation efficiency.


Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 201
Author(s):  
Dan Wang ◽  
Klaus Hubacek ◽  
Yuli Shan ◽  
Winnie Gerbens-Leenes ◽  
Junguo Liu

Production and consumption activities deplete freshwater, generate water pollution and may further lead to water stress. The accurate measurement of water stress is a precondition for sustainable water management. This paper reviews the literature on physical water stress induced by blue and green water use and by water pollution. Specifically, we clarify several key concepts (i.e., water stress, scarcity, availability, withdrawal, consumption and the water footprint) for water stress evaluation, and review physical water stress indicators in terms of quantity and quality. Furthermore, we identify research gaps in physical water stress assessment, related to environmental flow requirements, return flows, outsourcing of water pollution and standardization of terminology and approaches. These research gaps can serve as venues for further research dealing with the evaluation and reduction of water stress.


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