Evaluation of Water Supply Stability According to Changes in Instream Flow

The Daap intake plant located downstream of the Seomjin River was relocated in 2005, and the amount of intake increased. Accordingly, it significantly influenced the change in the flow rate downstream of the Seomjin River. After relocating the Daap intake plant, the production of Corbicula in the downstream of the Seomjin River decreased; there is a demand for investigation into the damage to the downstream fishermen and preparation of countermeasures. An increase in instream flow to increase the production of Corbicula downstream of the Seomjin River may cause difficulties in the stable water supply of the Seomjin River basin; therefore, a preliminary review is necessary. In this study, the supply stability was evaluated through water budget analysis after setting several instream flow at the downstream of the Seomjin River in Gurye-gun (Songjeong-ri). In addition, the supply stability of the water resource system in the Seomjin River according to the instream flow rate was evaluated. It was intended to suggest an alternative to the supply of instream flow. If the instream flow is set large to increase the production of Corbicula, it may cause difficulties in supplying instream flow and problems in supplying water necessary for human activities; therefore, related information must be provided through various analyses.

Hydrological time series prediction by extreme machine learning and sparrow search algorithm

In general, accurate hydrological time series prediction information is of great significance for the rational planning and management of water resource system. Extreme learning machine (ELM) is an effective tool proposed for the single-layer feedforward neural network in the regression and classification problems. However, the standard ELM model falls into local minimum with a high probability in hydrological prediction problems since the randomly assigned parameters (like input-hidden weights and hidden biases) often remain unchanged at the learning process. For effectively improving the prediction accuracy, this paper develops a hybrid hydrological forecasting model where the emerging sparrow search algorithm (SSA) is firstly used to determine the satisfying parameter combinations of the ELM model, and then the Moore-Penrose generalized inverse method is chosen to analytically obtain the weight matrix between the hidden layer and output layer. The proposed method is used to forecast the long-term daily runoff series collected from three real-world hydrological stations in China. Based on several performance evaluation indexes, the results show that the proposed method outperforms several ELM variants optimized by other evolutionary algorithms in both training and testing phases. Hence, an effective evolutionary machine learning tool is developed for accurate hydrological time series forecasting. HIGHLIGHT Hydrologic forecasting, sparrow search algorithm, extreme machine learning.

Integrated framework for rapid climate stress testing on a monthly timestep

“Bottom-up” methods are increasingly used to assess the vulnerability of water systems to climate change. Central to these methods is the climate “stress test”, where the system is subjected to various climatic changes to test for unacceptable outcomes. We present a framework for climate stress testing on a monthly timestep, suitable for systems whose dominant dynamic is seasonal or longer (eg. water resource systems with carry-over storage). The framework integrates multi-site stochastic climate generation with perturbation methods and in-built rainfall runoff modelling. The stochastic generation includes a low frequency component suitable for representing multi-annual fluctuations. Multiple perturbation options are provided, ranging from simple delta change through to altered seasonality and low frequency dynamics. The framework runs rapidly, supporting comprehensive multi-dimensional stress testing without recourse to supercomputing facilities. We demonstrate the framework on a large water resource system in southern Australia. The Matlab/Octave framework is freely available for download from https://doi.org/10.5281/zenodo.5617008.

Evolution of China’s Interprovincial Water Flow Network

Traditionally, water governance focuses on water only. The emergence of virtual water breaks this limitation and integrates economic and social systems with the water resource system. This paper establishes an interprovincial complex network of virtual water flows in China, based on the theory on complex network, which has rarely been adopted to study the virtual water transfer network. Then, the authors analyzed the pattern and evolutionary features of China’s interprovincial virtual water flow network. In this way, the complex network theory was successfully applied to explore the virtual water flows across provinces in China.

Simulation Of Reservoir Operation In A Multi Reservoir System

The present study aims to apply simulation software MIKE Basin for the operation of reservoirs of Mahanadi Reservoir Project (MRP) Complex. MRP complex is a multipurpose multi reservoir system. Simulation is a technique by which we emulate the behavior of a system. Simulation is a very powerful technique in analyzing most complex water resource system in detail for performance evaluation. Reservoir operation study has been done for data of 34 years. The results extracted from the study indicated that the performance of simulation model MIKE Basin is satisfactory.

Ecological network analysis of watershed meta-ecosystems: A new perspective on quantifying the integrated watershed ecosystem

A watershed is an integrated ecosystem. In different disciplines, a watershed has been described as a geomorphic unit, a hydrological unit, an ecological unit, or a socio-economic unit and has been quantitatively described using different indicator systems. Until now, no general indicator system has existed that could quantitatively describe the geomorphic features, hydrologic features, ecological features and socio-economic features of an integrated watershed ecosystem (IWE) simultaneously. Here, we proposed a quantitative descriptive framework for an IWE (QDFIWE). This QDFIWE involved three steps: (1) constructing a watershed meta-ecosystem (WME) based on the hierarchical system of the watershed; (2) constructing flow networks based on the WME; and (3) identifying the holistic properties (such as spatial throughput, spatial organization and spatial resilience) of the WME through analyzing its flow networks based on ecological network analysis (ENA). Then, we applied this method to study the geomorphic topological structure, geomorphic spatial structure, natural water resource system and integrated water resource system of the Yangtze River basin. The results suggested that based on the QDFIWE, (1) one could construct different WMEs and corresponding flow networks for different requirements; (2) one could obtain time series of the holistic properties of an IWE to analyze its evolution; (3) one could compare, classify and cluster any number of IWEs through identifying their holistic properties according to similar strategies; and (4) one could determine or create more indicators, which could provide additional information, based on the holistic properties of an IWE. This study demonstrates that the QDFIWE is a general method of quantifying the holistic properties of all subsystems of an IWE simultaneously. Thus, the method can improve the understanding of the IWE.

Assessment of Falaj Water Quality

Aflaj forms a significant water resource system in the Sultanate of Oman of which 92% is used for irrigation purposes while the rest is used for domestic works. Continous human interventions in this system are causing adverse effects on the natural flowing water quality before it can reach the end users. This research work assesses the quality of the Aflaj water system in the Wilayat of Samail, Sultanate of Oman. Also, various physical, chemical and biological parameters have been evaluated. It is concluded that the water quality is contaminated with biological content and needs proper disinfection to avoid adverse health issues in living beings.