scholarly journals Spatial Estimation of Reference Evapotranspiration in Andalusia, Spain

2008 ◽  
Vol 9 (2) ◽  
pp. 242-255 ◽  
Author(s):  
Karl Vanderlinden ◽  
Juan Vicente Giráldez ◽  
Marc Van Meirvenne
Keyword(s):  
Water Resources ◽  
Meteorological Data ◽  
Temporal Distribution ◽  
Spatial Optimization ◽  
Data Availability ◽  
Fine Tuning ◽  
Irrigated Agriculture ◽  
Estimation Errors ◽  
Secondary Information ◽  
Regional Water

Abstract Knowledge of the spatial and temporal distribution of reference crop evapotranspiration (ET0) is of interest for regional water resources management, especially in areas of the world where fine-tuning of agricultural water demands over large areas is required. This study provides a strategy for mapping ET0 in regions with low meteorological data availability. For Andalusia, Spain, it involves estimating ET0 from temperature data using a locally calibrated version of the Hargreaves equation and the application of geostatistical interpolation techniques that take into account elevation as secondary information. Average annual ET0 at 191 observatories (with elevation between 0 and 1260 m) ranged from 954 to 1460 mm, with an average of 1283 mm, a standard deviation of 99 mm, and a correlation coefficient with elevation of −0.86. Simple kriging with varying local means (SKlm) and kriging with an external drift (KED)—two methods that take into account elevation as secondary information—increased spatial model efficiency by 30% as compared to ordinary kriging. SKlm was used for mapping ET0 since it better reproduced the descriptive statistics of the point data and yielded slightly smaller root-mean-squared estimation errors than KED. The spatial correlation of annual and monthly ET0 was well structured and anisotropic. Short-range variability, for separation distances up to 20–40 km, showed a strong linear increase with distance while long-range variability, up to 130–250 km, increased more gently with distance. The results of this structural analysis are relevant for the spatial optimization of a recently installed automated ET0 observation network, while obtained maps constitute a valuable tool for regional water resources evaluation, planning, and management and contribute to optimizing water use in local irrigated agriculture.

scholarly journals A remote sensing-based approach for water accounting in the East Rapti River Basin, Nepal

2011 ◽  
Vol 7 (9) ◽  
pp. 15-30 ◽  
Author(s):  
Rajendra Lal Shilpakar ◽  
Wim G.M. Bastiaanssen ◽  
David J. Molden
Keyword(s):  
Remote Sensing ◽  
Water Resources ◽  
River Basin ◽  
River Flow ◽  
Riparian Forest ◽  
Meteorological Data ◽  
Irrigated Agriculture ◽  
International Water Management Institute ◽  
Water Accounting ◽  
Mountainous River

Accurate estimates of evapotranspiration across different land uses are a major challenge in the process of understanding water availability and uses in a river basin. This study demonstrated a remote sensing-based procedure for accurately generating evaporative depletion and runoff in mountainous areas using Landsat ETM+ images combined with standard hydro-meteorological data. The data was used as a key input into the International Water Management Institute (IWMI)’s water accounting procedure to understand how water is now used, and opportunities for improvements in the future. We found a higher annual actual evapotranspiration from the riparian forest than from irrigated agriculture in the East Rapti River basin of Nepal. Another important finding of our study is that simple rainfall surplus can be a good predictor of river flow at an ungagged site of the East Rapti River basin. The water accounting analysis revealed that there is the potential for further development of water resources in the East Rapti River basin as only 59% of the total available water is depleted. A critical analysis of social and ecological flow requirements downstream is necessary before any development of water resources upstream. This study successfully demonstrated that the key inputs required for evaluating and monitoring the overall water resources conditions in a mountainous river basin can be computed from satellite data with a minimal support from ground information.DOI: http://dx.doi.org/10.3126/hjs.v7i9.5785 Himalayan Journal of Sciences Vol.7 Issue 9 2011 pp.15-30

scholarly journals A Review of SWAT Model Application in Africa

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1313
Author(s):  
George Akoko ◽  
Tu Hoang Le ◽  
Takashi Gomi ◽  
Tasuku Kato
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Water Resources ◽  
Hydrological Modeling ◽  
Assessment Tool ◽  
Swat Model ◽  
Data Availability ◽  
Mitigation Measures ◽  
Model Parameterization ◽  
Basin Scale

The soil and water assessment tool (SWAT) is a well-known hydrological modeling tool that has been applied in various hydrologic and environmental simulations. A total of 206 studies over a 15-year period (2005–2019) were identified from various peer-reviewed scientific journals listed on the SWAT website database, which is supported by the Centre for Agricultural and Rural Development (CARD). These studies were categorized into five areas, namely applications considering: water resources and streamflow, erosion and sedimentation, land-use management and agricultural-related contexts, climate-change contexts, and model parameterization and dataset inputs. Water resources studies were applied to understand hydrological processes and responses in various river basins. Land-use and agriculture-related context studies mainly analyzed impacts and mitigation measures on the environment and provided insights into better environmental management. Erosion and sedimentation studies using the SWAT model were done to quantify sediment yield and evaluate soil conservation measures. Climate-change context studies mainly demonstrated streamflow sensitivity to weather changes. The model parameterization studies highlighted parameter selection in streamflow analysis, model improvements, and basin scale calibrations. Dataset inputs mainly compared simulations with rain-gauge and global rainfall data sources. The challenges and advantages of the SWAT model’s applications, which range from data availability and prediction uncertainties to the model’s capability in various applications, are highlighted. Discussions on considerations for future simulations such as data sharing, and potential for better future analysis are also highlighted. Increased efforts in local data availability and a multidimensional approach in future simulations are recommended.

Self-organising map rainfall-runoff multivariate modelling for runoff reconstruction in inadequately gauged basins

2012 ◽  
Vol 43 (5) ◽  
pp. 603-617 ◽  
Author(s):  
Adebayo J. Adeloye ◽  
Rabee Rustum
Keyword(s):  
Water Resources ◽  
Meteorological Data ◽  
Rainfall Runoff ◽  
Main River ◽  
Multivariate Modelling ◽  
Southwest Nigeria ◽  
Management Schemes ◽  
Viable Approach ◽  
Self Organising Map ◽  
Gauged Basins

Water resources assessment activities in inadequately gauged basins are often significantly constrained due to the insufficiency or total lack of hydro-meteorological data, resulting in huge uncertainties and ineffectual performance of water management schemes. In this study, a new methodology of rainfall-runoff modelling using the powerful clustering capability of the self-organising map (SOM), unsupervised artificial neural networks, is proposed as a viable approach for harnessing the multivariate correlation between the typically long record rainfall and short record runoff in such basins. The methodology was applied to the inadequately gauged Osun basin in southwest Nigeria for the sole purpose of extending the available runoff records and, through that, reducing water resources planning uncertainty associated with the use of short runoff data records. The extended runoff records were then analysed to determine possible abstractions from the main river source at different exceedance probabilities. This study demonstrates the successful use of emerging tools to overcome practical problems in sparsely gauged basins.

Quantitative estimation on contribution of climate changes and watershed characteristic changes to decreasing streamflow in the Huangshui Basin, China

2021 ◽  
Author(s):  
Xizhi Lv ◽  
Shaopeng Li ◽  
Yongxin Ni ◽  
Qiufen Zhang ◽  
Li Ma
Keyword(s):  
Water Resources ◽  
Climate Changes ◽  
Yellow River ◽  
Potential Evapotranspiration ◽  
Quantitative Estimation ◽  
Meteorological Data ◽  
Characteristic Parameter ◽  
Research Area ◽  
Watershed Characteristic ◽  
Streamflow Change

<p>In the past 60 years, climate changes and underlying surface of the watershed have affected the structure and characteristics of water resources to a different degree It is of great significance to investigate main drivers of streamflow change for development, utilization and planning management of water resources in river basins. In this study, the Huangshui Basin, a typical tributary of the upper Yellow River, is used as the research area. Based on the Budyko hypothesis, streamflow and meteorological data from 1958-2017 are used to quantitatively assess the relative contributions of changes in climate and watershed characteristic to streamflow change in research area. The results show that: the streamflow of Huangshui Basin shows an insignificant decreasing trend; the sensitivity coefficients of streamflow to precipitation, potential evapotranspiration and watershed characteristic parameter are 0.5502, -0.1055, and 183.2007, respectively. That is, an increase in precipitation by 1 unit will induce an increase of 0.5502 units in streamflow, and an increase in potential evapotranspiration by 1 unit will induce a decrease of 0.1055 units in streamflow, and an increase in the watershed characteristic parameter by 1 unit will induce a decrease of 183.2007 units in streamflow. Compared with the reference period (1958-1993), the streamflow decreased by 20.48mm (13.59%) during the change period (1994-2017), which can be attribution to watershed characteristic changes (accounting for 73.64%) and climate change (accounting for 24.48%). Watershed characteristic changes exert a dominant influence upon the reduction of streamflow in the Huangshui Basin.</p>

Runoff Forecast and Analysis of the Probability of Dry and Wet Transition in the Hanjiang River Basin

2021 ◽  
Author(s):  
Haoyu Jin ◽  
Xiaohong Chen ◽  
Ruida Zhong
Keyword(s):  
Water Resources ◽  
River Basin ◽  
Transition Probability ◽  
Conversion Model ◽  
Drought And Flood ◽  
Runoff Prediction ◽  
Runoff Forecast ◽  
Hanjiang River ◽  
Basin Area ◽  
Regional Water

Abstract Runoff prediction has an important guiding role in the planning and management of regional water resources, flood prevention and drought resistance, and can effectively predict the risk of changes in regional water resources. This study used 12 runoff prediction methods to predict the runoff of four hydrological stations in the Hanjiang River Basin (HRB). Through the MCMC method, the HRB runoff probability conversion model from low to high (high to low) is constructed. The study found that the runoff of the HRB had a decreasing trend. In the mid-1980s, the runoff had a significant decreasing trend. The smoother the runoff changes, the easier it is to make accurate prediction. On the whole, the QS-MFM, MFM, MA-MFM, CES and DNN methods have strong generalization ability and can more accurately predict the runoff of the HRB. The Logistic model can accurately simulate the change of runoff status in the HRB. Among them, the HLT station has the fastest conversion rate of drought and flood, and the flow that generates floods is 6 times that of drought. The smaller the basin area, the larger the gap between drought and flood discharge. Overall, this research provides important technical support for the prediction of change in water resources and the transition probability from drought to flood in the HRB.

scholarly journals The water crisis and its implications in Brazilian agribusiness: A bibliographic review

2020 ◽  
Vol 13 (1) ◽  
pp. 42
Author(s):  
O. S. Fagundes ◽  
L. C. A. Oliveira ◽  
O. M. Yamashita ◽  
I. V. Silva ◽  
M. A. C. Carvalho ◽  
...  
Keyword(s):  
Water Resources ◽  
Agricultural Practices ◽  
Industrial Effluents ◽  
Water Shortage ◽  
Irrigated Agriculture ◽  
Water Crisis ◽  
Negative Effects ◽  
Economic Sectors ◽  
Basic Sanitation ◽  
Environmental Good

Water scarcity has become one of the main global problems, since of all the water of the terrestrial surface, only 2.5% represents fresh water, and of this, only 0.3% corresponds to the water of the rivers and lakes that are available to supply the demand for food production and other uses. The present work consisted in surveying the scenario related to the global water crisis and presenting evidence that even Brazil being abundant in the amount of water available, tends to face serious problems because of its scarcity, affecting two of the main economic pillars, agribusiness and industry. It was observed that the main negative effects on water resources occur due to urban occupation and agricultural practices in a disorderly way, causing destruction of natural resources through the discharge of domestic sewage, industrial effluents and agrochemicals. In general, the lack of control of the use of the water directed to the productive processes is one of the major generators of the water shortage, since 69% of the water derived from rivers, lakes and aquifers underground is turned to irrigated agriculture, using 70 times more water than for domestic purposes. Thus, it is necessary to adopt policies aimed at the conservation and efficient use of water resources, to value water as a social, social and environmental good, since their scarcity can generate instability in economic sectors such as agriculture, generating production insecurity in industry, as well as affecting the supply of drinking water, basic sanitation and public health.

Sign in / Sign up

Export Citation Format

Share Document