Identifying and mitigating systematic biases in fish habitat simulation modeling: Implications for estimating minimum instream flows

Author(s):  
Jordan S. Rosenfeld ◽  
Sean M. Naman
2018 ◽  
Vol 10 (11) ◽  
pp. 4032 ◽  
Author(s):  
Kidoo Park ◽  
Kil Lee ◽  
Young-Oh Kim

Drought flow as the minimum flow rate required for restoration of the Mokgamcheon stream was calculated by the Storm Water Management Model (SWMM) V.5.0. The adequacy of drought flow to guarantee the minimum ecological environment was assessed using suitable low-flows not exceeding the maximum pollution concentration of the ecosystem calculated by Design FLOWs (DFLOW) V.4.1. Fish flows, which provide proper ecological habitat for fish, were calculated using Physical HABitat SIMulation (PHABSIM) V.1.5.2 to provide proper ecological habitat for target fishes such as Carassius auratus and Zacco platypus. The monthly expected instream flows were determined as the largest value between drought flow and fish flow. In most cases, instream flows were determined by drought flows exceeding fish flows that satisfy the condition of species habitat, but in the case of Carassius auratus, drought flows were less than fish flows in April, September, and October. Thus, structural measures for the supply of additional discharge were required. Instead, when natural environment-friendly instream structures, such as stepping stones were used, affordable ecological restoration that met the preferred conditions for discharge and depth of Carassius auratus was possible. The stepping stones were assessed using River2D V.0.95a to measure their effectiveness compared to other structural measures that would be costly and time-consuming to secure shortage of fish flow. Finally, the stability of the habitat was assessed through flood analysis; in case of a flood discharge of 5.2 m3/s obtained from time-series analysis, it was evaluated that the stability of habitats could be reasonable.


2007 ◽  
Vol 34 (1) ◽  
pp. 66-74 ◽  
Author(s):  
Daniel Caissie ◽  
Nassir El-Jabi ◽  
Cindie Hébert

The protection of fish habitat against the impact of water extraction in rivers is a recurring problem in water resources management. As such, a wide range of methodologies is available for the calculation of instream flows. This study focuses on historical streamflow methods that rely solely on hydrometric data for instream flow evaluation. The objectives of the study are to compare different historical streamflow methods and use a jackknife resampling technique to assess the variability of instream flow estimates. Results showed that methods based on a percentage of mean annual flow (MAF) generated higher levels of instream flow protection and showed low spatial and sample size variability. Low spatial variability makes the MAF methods more suitable for calculations of instream flows for ungauged basins. The Q50 method provided relatively high levels of instream flow protection; however, spatial and sample size variability were higher than those for the MAF methods. Lastly, the results showed that some methods generated low instream flow protection (namely, the Q90, 7Q2, and 7Q10 methods), especially for small streams, and thus are not recommended for use.Key words: instream flow, aquatic habitat, water withdrawal, impact assessment.


Hydrology ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 95
Author(s):  
Susan R. Bresney ◽  
Laura Forni ◽  
Marina R. L. Mautner ◽  
Annette Huber-Lee ◽  
Manish Shrestha ◽  
...  

The interlinkages between water for irrigation and for fish habitat are complex. This is particularly true in the Stung Chinit, a tributary to one of the most robust fisheries in the world, where livelihoods rely heavily on rice production and fishing and there is pressure to increase rice production with increased irrigation. This study assesses the tradeoffs between various management options and irrigation strategies in the Stung Chinit watershed under multiple projections of climate change. Due to the relative demands for instream flows and rice, if dry season rice is widely promoted, flows will be severely impacted. However, implementing a flow requirement protects these flows, while only causing minor shortages to rice when planted once or twice per year. These shortages may be alleviated with improved cooperation, management and shifting rice irrigation practices. While climate change will lead to warming temperatures and potentially higher demands for irrigation, the larger threat to rice and ecosystems appears to be water management (or lack thereof). This study suggests that there is sufficient water in the system to expand the irrigated area by 10%, grow rice twice per year and protect downstream flows under climate change; however, well-coordinated management is required to achieve this.


2021 ◽  
Vol 267 ◽  
pp. 01022
Author(s):  
Wenxiu Shang ◽  
Dengming Yan ◽  
Shaoming Peng

The accuracy of the habitat simulation method is often questioned due to limited simulated elements and indicator species. This study established an environmental flow assessment method by coupling fish habitat simulation with hydrological reference system. The environmental flow obtained through the habitat simulation method was corrected by the statistical characteristics of natural flow regime. The environmental flow of the Huayuankou section in the Lower Yellow River was assessed. The results show that the environmental flow demand of the Huayuankou section is 7.9 - 15.4 billion m3/y without consideration of sediment transport. An environmental baseflow of 220 - 400 m3/s is required throughout the year. One to two high flow pulses are needed in the rising-water season to trigger spawning, followed by flow events of 350 - 500 m3/s with more than 1 week duration to create the spawning grounds.


2020 ◽  
Vol 17 (5) ◽  
pp. 34-47
Author(s):  
V. M. Polyakov ◽  
Z. S. Agalarov

The article offers a method for assessing the environmental risk in the territories adjacent to the planning zone of emergency protection measures around the NPP. The method is based on simulation modeling of territory pollution, which is formed at the late stage of a radiation accident and zoning of territories by risk, taking into account the characteristics of the population’s life in a potentially dangerous territory. A vector criterion of environmental risk is proposed that allows zoning these territories according to the degree of danger to the population.


2020 ◽  
Vol 17 (1) ◽  
pp. 58-67
Author(s):  
N. A. Kabanova ◽  
I. K. Alekseeva

The article is devoted to the assessment of potential investment risks of the pharmaceutical company “R-Pharm” JSC with the aim of identifying the highest priority risks and developing methods for minimizing them. The relevance of the study is determined by the fact that the pharmaceutical business is characterized by a high degree of social orientation and annually invests $ 140 billion in the development of production and research, which determines the need for a risk-based approach to ensure the return on investment. The subject of this article is the investment risks of pharmaceutical companies, and the subject of research is the domestic pharmaceutical company “R-Pharm”. In order to assess the potential investment risks of “R-Pharm” JSC, the authors used elements of simulation modeling and system analysis. The proposed methods to minimize key investment risks are aimed at improving the efficiency of investment activities and is recommended as an element of the strategic planning of the company.


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