scholarly journals Long-term changes of river discharge regime in Latvia

2008 ◽  
Vol 39 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Maris Klavins ◽  
Valery Rodinov
Keyword(s):  
Climate Variability ◽  
River Discharge ◽  
Water Resource Management ◽  
Regional Climate ◽  
Hydrological Regime ◽  
High Water ◽  
Regime Changes ◽  
Long Term Changes ◽  
Discharge Regime

The study of changes in river discharge is important for regional climate variability characterization and for development of an efficient water resource management system. The hydrological regime of rivers and their long-term changes in Latvia were investigated. Four major types of river hydrological regimes, which depend on climatic and physicogeographic factors, were characterized. These factors are linked to the changes observed in river discharge. Periodic oscillations of discharge, and low- and high-water flow years are common for the major rivers in Latvia. A main frequency of river discharge regime changes of about 20 and 13 years was estimated for the studied rivers. A significant impact of climate variability on the river discharge regime has been found.

scholarly journals Future Changes in Wave Conditions at the German Baltic Sea Coast Based on a Hybrid Approach Using an Ensemble of Regional Climate Change Projections

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 167
Author(s):  
Norman Dreier ◽  
Edgar Nehlsen ◽  
Peter Fröhle ◽  
Diana Rechid ◽  
Laurens M. Bouwer ◽  
...  
Keyword(s):  
21St Century ◽  
Wind Wave ◽  
Regional Climate ◽  
Hybrid Approach ◽  
Wave Modelling ◽  
Long Term Changes ◽  
Mean Wave Period ◽  
Wave Conditions ◽  
Sea Coast

In this study, the projected future long-term changes of the local wave conditions at the German Baltic Sea coast over the course of the 21st century are analyzed and assessed with special focus on model agreement, statistical significance and ranges/spread of the results. An ensemble of new regional climate model (RCM) simulations with the RCM REMO for three RCP forcing scenarios was used as input data. The outstanding feature of the simulations is that the data are available with a high horizontal resolution and at hourly timesteps which is a high temporal resolution and beneficial for the wind–wave modelling. A new data interface between RCM output data and wind–wave modelling has been developed. Suitable spatial aggregation methods of the RCM wind data have been tested and used to generate input for the calculation of waves at quasi deep-water conditions and at a mean water level with a hybrid approach that enables the fast compilation of future long-term time series of significant wave height, mean wave period and direction for an ensemble of RCM data. Changes of the average wind and wave conditions have been found, with a majority of the changes occurring for the RCP8.5 forcing scenario and at the end of the 21st century. At westerly wind-exposed locations mainly increasing values of the wind speed, significant wave height and mean wave period have been noted. In contrast, at easterly wind-exposed locations, decreasing values are predominant. Regarding the changes of the mean wind and wave directions, westerly directions becoming more frequent. Additional research is needed regarding the long-term changes of extreme wave events, e.g., the choice of a best-fit extreme value distribution function and the spatial aggregation method of the wind data.

scholarly journals Development and Verification of the Available Number of Water Intake Days in Ungauged Local Water Source Using the SWAT Model and Flow Recession Curves

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1511
Author(s):  
Jung-Ryel Choi ◽  
Il-Moon Chung ◽  
Se-Jin Jeung ◽  
Kyung-Su Choo ◽  
Cheong-Hyeon Oh ◽  
...  
Keyword(s):  
Water Supply ◽  
Water Intake ◽  
Water Resource Management ◽  
Assessment Tool ◽  
Swat Model ◽  
High Water ◽  
Coefficient Of Determination ◽  
Severe Drought ◽  
Regional Government

Climate change significantly affects water supply availability due to changes in the magnitude and seasonality of runoff and severe drought events. In the case of Korea, despite high water supply ratio, more populations have continued to suffer from restricted regional water supplies. Though Korea enacted the Long-Term Comprehensive Water Resources Plan, a field survey revealed that the regional government organizations limitedly utilized their drought-related data. These limitations present a need for a system that provides a more intuitive drought review, enabling a more prompt response. Thus, this study presents a rating curve for the available number of water intake days per flow, and reviews and calibrates the Soil and Water Assessment Tool (SWAT) model mediators, and found that the coefficient of determination, Nash–Sutcliffe efficiency (NSE), and percent bias (PBIAS) from 2007 to 2011 were at 0.92, 0.84, and 7.2%, respectively, which were “very good” levels. The flow recession curve was proposed after calculating the daily long-term flow and extracted the flow recession trends during days without precipitation. In addition, the SWAT model’s flow data enables the quantitative evaluations of the number of available water intake days without precipitation because of the high hit rate when comparing the available number of water intake days with the limited water supply period near the study watershed. Thus, this study can improve drought response and water resource management plans.

Long-term changes in the benthic communities of the Sea of Azov related to the sedimentation and hydrological regime

Oceanology ◽  
2008 ◽  
Vol 48 (3) ◽  
pp. 390-400 ◽  
Author(s):  
G. G. Matishov ◽  
I. V. Shokhin ◽  
M. V. Nabozhenko ◽  
V. V. Pol’shin
Keyword(s):  
Benthic Communities ◽  
Hydrological Regime ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
Long Term Changes

scholarly journals Climate Change Impacts on Groundwater Recharge in Cold and Humid Climates: Controlling Processes and Thresholds

Climate ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 6
Author(s):  
Emmanuel Dubois ◽  
Marie Larocque ◽  
Sylvain Gagné ◽  
Marco Braun
Keyword(s):  
Climate Change ◽  
Groundwater Recharge ◽  
Water Resource Management ◽  
Global Climate Models ◽  
Future Climate Change ◽  
Temperature Changes ◽  
Wide Range ◽  
Long Term Changes ◽  
Precipitation And Temperature

Long-term changes in precipitation and temperature indirectly impact aquifers through groundwater recharge (GWR). Although estimates of future GWR are needed for water resource management, they are uncertain in cold and humid climates due to the wide range in possible future climatic conditions. This work aims to (1) simulate the impacts of climate change on regional GWR for a cold and humid climate and (2) identify precipitation and temperature changes leading to significant long-term changes in GWR. Spatially distributed GWR is simulated in a case study for the southern Province of Quebec (Canada, 36,000 km2) using a water budget model. Climate scenarios from global climate models indicate warming temperatures and wetter conditions (RCP4.5 and RCP8.5; 1951–2100). The results show that annual precipitation increases of >+150 mm/yr or winter precipitation increases of >+25 mm will lead to significantly higher GWR. GWR is expected to decrease if the precipitation changes are lower than these thresholds. Significant GWR changes are produced only when the temperature change exceeds +2 °C. Temperature changes of >+4.5 °C limit the GWR increase to +30 mm/yr. This work provides useful insights into the regional assessment of future GWR in cold and humid climates, thus helping in planning decisions as climate change unfolds. The results are expected to be comparable to those in other regions with similar climates in post-glacial geological environments and future climate change conditions.

scholarly journals Assessing the Rate of Shoreline Changes of Rameswaram Island, Tamilnadu, India, using MATLAB Component Runtime Utility & Digital Shoreline Analysis System

2020 ◽  
Vol 9 (3) ◽  
pp. 3318-3321
Keyword(s):  
High Water ◽  
Field Investigation ◽  
Rate Of Change ◽  
Physical Parameters ◽  
Geospatial Technology ◽  
Water Line ◽  
Digital Shoreline Analysis System ◽  
Long Term Changes ◽  
Analysis System

The Present study highlights the changes in the coastal tract of Rameswaram island located between the geometric location, latitude 9° 10' to 9° 20' N and the longitude 79° 12' to 79° 30' E. Using Geospatial Technology, Long-term changes have noticed from digitized shorelines taken from Landsat imageries and SOI toposheet for the years 1968, 1978, 1988, 1999, 2009 and 2018. Digital Shoreline Analysis System (DSAS) an extension provided by USGS for ArcGIS used to cast transects perpendicular from the baseline, towards the shorelines. High water Line (HTL) has taken as shoreline in this study. The distance between the shorelines has taken from the cast transects plotted from the baseline. For the rate of change calculation, MATLAB component runtime utility for ArcGIS has used. Based on the Linear Regression Rate (LRR) the shore has classified into High Erosion, Low Erosion, Stable and Low Accretion, High Accretion zones. The island has a shoreline length of 78.4 km, and the studies found that 27.83 km (35.41%) of shoreline is accreting nature, 37.90 km (48.21%) of shoreline is stable, and 12.86 km (16.36 %) of shoreline tends to erode. During the field investigation identified that High amount of erosion occurred in the locations near Pamban, Tharavaithopu and Dhanushkodi. Also, Accretion identified over the locations Ayyanthopu, Natarajapuram and Arichumanai tip. Wind action is one of the physical parameters that induced the erosion in some location of this study area.

scholarly journals Long-Term Changes of Aquatic Invasive Plants and Implications for Future Distribution: A Case Study Using a Tank Cascade System in Sri Lanka

Climate ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 31
Author(s):  
Champika S. Kariyawasam ◽  
Lalit Kumar ◽  
Benjamin Kipkemboi Kogo ◽  
Sujith S. Ratnayake
Keyword(s):  
Sri Lanka ◽  
Climate Variability ◽  
Annual Rainfall ◽  
Trend Test ◽  
P Value ◽  
Positive Trend ◽  
Cascade System ◽  
Landsat Images ◽  
Long Term Changes

Climate variability can influence the dynamics of aquatic invasive alien plants (AIAPs) that exert tremendous pressure on aquatic systems, leading to loss of biodiversity, agricultural wealth, and ecosystem services. However, the magnitude of these impacts remains poorly known. The current study aims to analyse the long-term changes in the spatio-temporal distribution of AIAPs under the influence of climate variability in a heavily infested tank cascade system (TCS) in Sri Lanka. The changes in coverage of various features in the TCS were analysed using the supervised maximum likelihood classification of ten Landsat images over a 27-year period, from 1992 to 2019 using ENVI remote sensing software. The non-parametric Mann–Kendall trend test and Sen’s slope estimate were used to analyse the trend of annual rainfall and temperature. We observed a positive trend of temperature that was statistically significant (p value < 0.05) and a positive trend of rainfall that was not statistically significant (p values > 0.05) over the time period. Our results showed fluctuations in the distribution of AIAPs in the short term; however, the coverage of AIAPs showed an increasing trend in the study area over the longer term. Thus, this study suggests that the AIAPs are likely to increase under climate variability in the study area.

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