Study on the impact of water delivery velocity of aqueduct on water temperature

2021 ◽  
Author(s):  
YouWen Xu ◽  
Weiyou Wang ◽  
Richen Ji
Keyword(s):  
Water Temperature ◽  
Water Delivery ◽  
The Impact

scholarly journals Extreme Meteorological Events in a Coastal Lagoon Ecosystem: The Ria de Aveiro Lagoon (Portugal) Case Study

2021 ◽  
Vol 9 (7) ◽  
pp. 727
Author(s):  
José Fortes Lopes ◽  
Carina Lurdes Lopes ◽  
João Miguel Dias
Keyword(s):  
Water Temperature ◽  
Coastal Lagoon ◽  
Early Summer ◽  
Extreme Weather Events ◽  
Climate Change Scenarios ◽  
State Variables ◽  
Ria De Aveiro ◽  
Physical Conditions ◽  
Weather Events ◽  
The Impact

Extreme weather events (EWEs) represent meteorological hazards for coastal lagoon hydrodynamics, of which intensity and frequency are increasing over the last decades as a consequence of climate changes. The imbalances they generated should affect primarily vulnerable low-lying areas while potentially disturbing the physical balances (salt and water temperature) and, therefore, the ecosystem equilibrium. This study arises from the need to assess the impact of EWEs on the Ria de Aveiro, a lagoon situated in the Portuguese coastal area. Furthermore, it was considered that those events occur under the frame of a future sea-level rise, as predicted by several climate change scenarios. Two EWEs scenarios, a dry and an extremely wet early summer reflecting past situations and likely to occur in the future, were considered to assess the departure from the system baseline functioning. It was used as a biogeochemistry model that simulates the hydrodynamics, as well as the baseline physical and biogeochemistry state variables. The dry summer scenario, corresponding to a significant reduction in the river’s inflow, evidences a shift of the system to a situation under oceanic dominance characterized by colder and saltier water (~18 °C; 34 PSU) than the baseline while lowering the concentration of the nutrients and reducing the phytoplankton population to a low-level limit. Under a wet summer scenario, the lagoon shifted to a brackish and warmer situation (~21 °C, <15 PSU) in a time scale of some tidal periods, driven by the combining effect of the tidal transport and the river’s inflow. Phytoplankton patterns respond to variability on local and short-term scales that reflect physical conditions within the lagoon, inducing nutrient-supported growth. Overall, the results indicate that EWEs generate local and transient changes in physical conditions (namely salinity and water temperature) in response to the characteristic variability of the lagoon’s hydrodynamics associated with a tidal-dominated system. Therefore, in addition to the potential impact of changing physical conditions on the ecosystem, saline intrusion along the lagoon or the transfer of brackish water to the mouth of the system are the main consequences of EWEs, while the main biogeochemistry changes tend to remain moderate.

scholarly journals Longitudinal sampling of external mucosae in farmed European seabass reveals the impact of water temperature on bacterial dynamics

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Daniela Rosado ◽  
Raquel Xavier ◽  
Jo Cable ◽  
Ricardo Severino ◽  
Pedro Tarroso ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Microbial Diversity ◽  
Water Temperature ◽  
Abiotic Factors ◽  
Seasonal Effect ◽  
Microbial Composition ◽  
Surrounding Water ◽  
European Seabass ◽  
And Function ◽  
The Impact

AbstractFish microbiota are intrinsically linked to health and fitness, but they are highly variable and influenced by both biotic and abiotic factors. Water temperature particularly limits bacterial adhesion and growth, impacting microbial diversity and bacterial infections on the skin and gills. Aquaculture is heavily affected by infectious diseases, especially in warmer months, and industry practices often promote stress and microbial dysbiosis, leading to an increased abundance of potentially pathogenic bacteria. In this regard, fish mucosa health is extremely important because it provides a primary barrier against pathogens. We used 16 rRNA V4 metataxonomics to characterize the skin and gill microbiota of the European seabass, Dicentrarchus labrax, and the surrounding water over 12 months, assessing the impact of water temperature on microbial diversity and function. We show that the microbiota of external mucosae are highly dynamic with consistent longitudinal trends in taxon diversity. Several potentially pathogenic genera (Aliivibrio, Photobacterium, Pseudomonas, and Vibrio) were highly abundant, showing complex interactions with other bacterial genera, some of which with recognized probiotic activity, and were also significantly impacted by changes in temperature. The surrounding water temperature influenced fish microbial composition, structure and function over time (days and months). Additionally, dysbiosis was more frequent in warmer months and during transitions between cold/warm months. We also detected a strong seasonal effect in the fish microbiota, which is likely to result from the compound action of several unmeasured environmental factors (e.g., pH, nutrient availability) beyond temperature. Our results highlight the importance of performing longitudinal studies to assess the impact of environmental factors on fish microbiotas.

scholarly journals Environmental Change Threatens Freshwater Insect Communities in Northwest Africa: A Meta-Analysis

2021 ◽  
Vol 9 ◽  
Author(s):  
Nils Kaczmarek ◽  
Ralf B. Schäfer ◽  
Elisabeth Berger
Keyword(s):  
Climate Change ◽  
Water Temperature ◽  
Negative Binomial ◽  
Small Body ◽  
Future Research ◽  
Insect Communities ◽  
Data Set ◽  
Temperature Conductivity ◽  
Northwest Africa ◽  
The Impact

A climatic shift from temperate to arid conditions is predicted for Northwest Africa. Water temperature, salinity, and river intermittency are likely to increase, which may impact freshwater communities, ecosystem functioning, and related ecosystem services. Quantitative data and information on the impact of climate change on insect communities (e.g., richness, taxonomic and trait composition) are still scarce for Northwest Africa. In this study, we extracted information on freshwater insect occurrence and environmental variables in Northwest Africa from the results of a literature search to study potential consequences of changing climatic conditions for these communities. Our data set covered 96 families in 165 sites in Morocco and Algeria. We quantified the impact of several explanatoryvariables (climate, altitude, water temperature, conductivity, intermittency, flow, aridity, dams, and land cover) on richness, taxonomic and functional trait composition using negative binomial regression models and constrained ordination. Family richness in arid sites was on average 37 % lower than in temperate sites in association with flow, river regulation, cropland extent, conductivity, altitude, and water temperature. With 36 % of the studied temperate sites predicted to turn arid by the end of the century, a loss of insect families can be predicted for Northwest Africa, mainly affecting species adapted to temperate environments. Resistance and resilience traits such as small body size, aerial dispersal, and air breathing promote survival in arid climates. Future research should report insect occurrences on species level to allow for better predictions on climate change effects.

Transferring irrigation management to farmer's associations: Evidence from the Philippines

Water Policy ◽  
2009 ◽  
Vol 12 (3) ◽  
pp. 444-460 ◽  
Author(s):  
Sushenjit Bandyopadhyay ◽  
Priya Shyamsundar ◽  
Mei Xie
Keyword(s):  
Irrigation Management ◽  
The Philippines ◽  
Farm Households ◽  
Water Delivery ◽  
Irrigation Management Transfer ◽  
Rice Farmers ◽  
Rice Yields ◽  
Canal Maintenance ◽  
The Impact ◽  
Irrigation Infrastructure

Irrigation management transfer (IMT) is an important strategy among donors and governments that aims to strengthen farmer control over water and irrigation infrastructure. In this study, we use data from a survey of 68 irrigator associations (IAs) and 1020 farm households in the Philippines to examine the impact of IMT on irrigation association performance and on rice yields. We find that the presence of IMT is associated with an increase in maintenance activities undertaken by irrigation associations. While associations with and without IMT contracts undertake canal maintenance, the frequency of maintenance in IMT IAs is higher. IMT presence is also associated with an increase in farm yields by about 6%; rice production in IMT areas is higher even after we control for various differences amongst rice farmers in IMT and non-IMT areas. Finally, IMT may even give poorer farmers a small boost in terms of rice yields. We speculate that this boost may be a result of improved water delivery and better resolution of conflicts related to illegal use.

scholarly journals Climate Change Impact in the Ria de Aveiro Lagoon Ecosystem: A Case Study

2019 ◽  
Vol 7 (10) ◽  
pp. 352 ◽  
Author(s):  
Lopes ◽  
Lopes ◽  
Dias
Keyword(s):  
Climate Change ◽  
Water Temperature ◽  
Sea Level Rise ◽  
Sea Level ◽  
Inorganic Nitrogen ◽  
Nitrogen Concentration ◽  
Ria De Aveiro ◽  
Global Sea Level ◽  
The Impact ◽  
Aveiro Lagoon

Climate change and global sea-level rise are major issues of the 21st century. The main goal of this study is to assess the physical and biogeochemical status of the Ria de Aveiro lagoon (Portugal) under future climate scenarios, using a coupled physical/ eutrophication model. The impact on the lagoon ecosystem status of the mean sea level rise (MSLR), the amplitude rise of the M2 tidal constituent (M2R), the changes in the river discharge, and the rising of the air temperature was investigated. Under MSLR and M2R, the results point to an overall salinity increase and water temperature decrease, revealing ocean water dominance. The main lagoon areas presented salinity values close to those of the ocean waters (~34 PSU), while a high range of salinity was presented for the river and the far end areas (20–34 PSU). The water temperature showed a decrease of approximately 0.5–1.5 °C. The responses of the biogeochemical variables reflect the increase of the oceanic inflow (transparent and nutrient-poor water) or the reduction of the river flows (nutrient-rich waters). The results evidenced, under the scenarios, an overall decreasing of the inorganic nitrogen concentration and the carbon phytoplankton concentrations. A warm climate, although increasing the water temperature, does not seem to affect the lagoon’s main status, at least in the frame of the model used in the study.

scholarly journals Comparison of Methods to Estimate Lake-Surface-Water Temperature Using Landsat 7 ETM+ and MODIS Imagery: Case Study of a Large Shallow Subtropical Lake in Southern Brazil

Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 168 ◽  
Author(s):  
Matheus Tavares ◽  
Augusto Cunha ◽  
David Motta-Marques ◽  
Anderson Ruhoff ◽  
J. Cavalcanti ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Temperature ◽  
Single Channel ◽  
Atmospheric Correction ◽  
Ecological Status ◽  
Surface Water Temperature ◽  
Lake Surface ◽  
Subtropical Lake ◽  
Landsat 7 ◽  
The Impact

Water temperature regulates many processes in lakes; therefore, evaluating it is essential to understand its ecological status and functioning, and to comprehend the impact of climate change. Although few studies assessed the accuracy of individual sensors in estimating lake-surface-water temperature (LSWT), comparative analysis considering different sensors is still needed. This study evaluated the performance of two thermal sensors, MODIS and Landsat 7 ETM+, and used Landsat methods to estimate the SWT of a large subtropical lake. MODIS products MOD11 LST and MOD28 SST were used for comparison. For the Landsat images, the radiative transfer equation (RTE), using NASA’s Atmospheric Correction Parameter Calculator (AtmCorr) parameters, was compared with the single-channel algorithm in different approaches. Our results showed that MOD11 obtained the highest accuracy (RMSE of 1.05 ° C), and is the recommended product for LSWT studies. For Landsat-derived SWT, AtmCorr obtained the highest accuracy (RMSE of 1.07 ° C) and is the recommended method for small lakes. Sensitivity analysis showed that Landsat-derived LSWT using the RTE is very sensitive to atmospheric parameters and emissivity. A discussion of the main error sources was conducted. We recommend that similar tests be applied for Landsat imagery on different lakes, further studies on algorithms to correct the cool-skin effect in inland waters, and tests of different emissivity values to verify if it can compensate for this effect, in an effort to improve the accuracy of these estimates.

Study on the Impact of Water Environmental Factors on Dominant Species of Phytoplankton around the Power Plant in Xiangshan Bay

2012 ◽  
Vol 610-613 ◽  
pp. 3371-3374 ◽  
Author(s):  
Hong Yang ◽  
Ying Zhao ◽  
Hui Rong Zhang ◽  
Gui Xiang Dai ◽  
Jun Ding ◽  
...  
Keyword(s):  
Power Plant ◽  
Environmental Factors ◽  
Statistical Model ◽  
Water Temperature ◽  
Temperature Increase ◽  
Dominant Species ◽  
Thermal Discharge ◽  
Xiangshan Bay ◽  
The Impact ◽  
Growth And Reproduction

The SPSS19.0 software was used to analyse the data of enclosure experiments last for 7 days in summer of 2011. Water temperature increase as a factor to establish the statistical model, and the response relation of thermal discharge warming and Coscinodiscus Jonesianus biomass was analyzed quantitatively. The results showed that, it would promote Coscinodiscus Jonesianus growth and reproduction with the water warming at 0.2°C to 0.79°C , which would be restrained at the water warming at 0.8°C to 2.0°C. When the water temperature increase 0.1°C, 0.4°C and 0.7°Cwill respectively result in Coscinodiscus Jonesianus biomass grow 216.12%, 72.87% and 15.05%. While the water temperature increase 1.0°C, 1.5°C and 2.0°C will respectively result in Coscinodiscus Jonesianus biomass reduce 6.38%, 17.95% and 26.17%.

A regional analysis of the impact of dams on water temperature in medium-size rivers in eastern Canada

2016 ◽  
Vol 73 (12) ◽  
pp. 1885-1897 ◽  
Author(s):  
Audrey Maheu ◽  
André St-Hilaire ◽  
Daniel Caissie ◽  
Nassir El-Jabi ◽  
Guillaume Bourque ◽  
...  
Keyword(s):  
Water Temperature ◽  
Thermal Regime ◽  
Regional Scale ◽  
Regional Analysis ◽  
Annual Runoff ◽  
Rate Of Change ◽  
Medium Size ◽  
Regulated Rivers ◽  
Eastern Canada ◽  
The Impact

Various studies have helped gain a better understanding of the thermal impacts of dams on a site-specific basis, but very few studies have compared the thermal impacts of varying types of dams within the same region. In this study, we conducted a regional-scale assessment of the impacts of dams on the thermal regime of 13 medium-size rivers in eastern Canada. The objectives of this study were to identify features of the thermal regime of rivers that are predominantly impacted by dams and to compare the impacts associated with different types of regulation (run-of-river, storage, peaking). The thermal regime of regulated and unregulated rivers was characterized using 15 metrics that described the magnitude, frequency, duration, timing, and rate of change of water temperature. Results indicate that storage and peaking dams impounding at least 10% of the median annual runoff generally (i) reduced the magnitude of water temperature variation at seasonal, daily, and subdaily timescales and (ii) increased the monthly mean water temperature in September. This regional assessment offers important insight regarding a generalized pattern of thermal alteration by dams, and this information could be used to guide biological monitoring efforts in regulated rivers.

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