scholarly journals Water Appropriation on the Agricultural Frontier in Western Bahia and Its Contribution to Streamflow Reduction: Revisiting the Debate in the Brazilian Cerrado

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1054
Author(s):  
Andréa Leme da Silva ◽  
Saulo Aires de Souza ◽  
Osmar Coelho Filho ◽  
Ludivine Eloy ◽  
Yuri Botelho Salmona ◽  
...  
Keyword(s):  
Time Series ◽  
River Basin ◽  
Hydrological Cycle ◽  
Land Use Changes ◽  
Interdisciplinary Approach ◽  
Fold Increase ◽  
Kendall Test ◽  
Annual Data ◽  
Precipitation Time Series ◽  
Agricultural Frontier

Over the last three decades, almost half of the Brazilian tropical savanna (Cerrado biome) has been converted into cropland and planted pastures. This study aims to understand the implications of the expansion of the agricultural frontier for water resources in western Bahia state. We use an interdisciplinary approach that combines quantitative and qualitative data (spatial and hydrological analysis, interviews) to tie together land use changes in the Corrente basin, the streamflow and precipitation time series in the Pratudão River sub-basin (part of the Corrente basin), and the perceptions of soybean farmers and smallholder communities about the transformations of the hydrological cycle over the last few years. We observed an almost 10-fold increase in agricultural surface area in the Corrente River basin over the last three decades (1986–2018), going on from 57,090 ha to 565,084 ha, while center-pivot irrigated areas increased from 240 ha to 43,631 ha. Over this period, the streamflow has reduced by 38% in the Pratudão River. Our hydrological analyses, based on the Mann-Kendall test, of seven fluviometric stations and 14 pluviometry stations showed a statistically significant streamflow trend in the Pratudão River sub-basin for both minimum and mean streamflow series (p ≤0.05). Surface runoff coefficient, which relates streamflow and precipitation annual data coefficient, decreased from around 0.4 in the late 1990s to less than 0.2 in 2015. In addition, most precipitation time series analysis (number of annual rainy days) showed no statistically significant trend (p > 0.05). Our results indicate that agricultural changes rather than climate change may be the main driver of downward streamflow trends in the Pratudão River sub-basin that is part of Corrente River basin.

scholarly journals Assessment of the impact of climate change on the freshwater availability of Kaduna River basin, Nigeria

2018 ◽  
Vol 38 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Gloria C. Okafor ◽  
Kingsley N. Ogbu
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Water Availability ◽  
Hydrological Cycle ◽  
Temporal Trends ◽  
Kendall Test ◽  
Well Being ◽  
Trend Test ◽  
Climate Indices ◽  
The Impact

AbstractChanges in runoff trends have caused severe water shortages and ecological problems in agriculture and human well-being in Nigeria. Understanding the long-term (inter-annual to decadal) variations of water availability in river basins is paramount for water resources management and climate change adaptation. Climate change in Northern Nigeria could lead to change of the hydrological cycle and water availability. Moreover, the linkage between climatic changes and streamflow fluctuations is poorly documented in this area. Therefore, this study examined temporal trends in rainfall, temperature and runoff records of Kaduna River basin. Using appropriate statistical tools and participatory survey, trends in streamflow and their linkages with the climate indices were explored to determine their amplifying impacts on water availability and impacts on livelihoods downstream the basin. Analysis indicate variable rainfall trend with significant wet and dry periods. Unlike rainfall, temperature showed annual and seasonal scale statistically increasing trend. Runoff exhibit increasing tendency but only statistically significant on annual scale as investigated with Mann–Kendall trend test. Sen’s estimator values stood in agreement with Mann–Kendall test for all variables. Kendall tau and partial correlation results revealed the influence of climatic variables on runoff. Based on the survey, some of the hydrological implications and current water stress conditions of these fluctuations for the downstream inhabitants were itemized. With increasing risk of climate change and demand for water, we therefore recommend developing adaptive measures in seasonal regime of water availability and future work on modelling of the diverse hydrological characteristics of the entire basin.

Precipitation Trend Analysis by Mann-Kendall Test: A Case of Tianchang County Anhui Province, China

2013 ◽  
Vol 864-867 ◽  
pp. 2218-2223 ◽  
Author(s):  
Elsie Akwei ◽  
Bao Hong Lu ◽  
Han Wen Zhang
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Trend Analysis ◽  
Null Hypothesis ◽  
Kendall Test ◽  
Anhui Province ◽  
Significant Trend ◽  
Precipitation Data ◽  
Precipitation Time Series ◽  
Mann Kendall Test

The purpose of this research is to study the temporal variability of precipitation time series of Tianchang County in Anhui Province, China to aid in the understanding of the state of the hydrology of the catchment. Trend analysis of one of the main component of the water balance of a catchment and a climate variable, precipitation was conducted with the aim of detecting a possible trend in the precipitation time series of Tianchang County, the non-parametric Mann-Kendall test was applied to precipitation series from 1951-2010 of Tianchang County. It was performed using Trend (version 1.0.2) to identify the significant positive or negative trends in the precipitation data if any. The 59 years period of precipitation data for the different towns in whole area showed, on the whole, some significant trend at an alpha level of 0.01 and 0.05 when grouped into the four seasons present in the area. The trend analysis revealed an overall upward and significant trend in five towns namely Datong, Xinjie, Shiliang, Qinlan and Tongcheng with downward statistically non-significant trend in the other ten areas .Using hypothesis testing, the null hypothesis states that there is no trend and alternative state there is a trend. From the results we reject the null hypothesis within the level of confidence 0.05 and 0.01. The rising rate of precipitation in some months and decreasing in others signifies an overall random pattern in the time series. This result is a part contribution to the effect of Climate change on hydrology and indicates that there is still room for research on the impact of climate change to ensure sustainable development in future.

Evaluation of changes in streamflow and the underlying causes: a perspective of an upstream catchment in Haihe River basin, China

2018 ◽  
Vol 11 (1) ◽  
pp. 241-257 ◽  
Author(s):  
Sicheng Wan ◽  
Jianyun Zhang ◽  
Guoqing Wang ◽  
Lu Zhang ◽  
Lei Cheng ◽  
...  
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Human Activities ◽  
Hydrological Cycle ◽  
Kendall Test ◽  
Haihe River Basin ◽  
Changing Environment ◽  
Haihe River ◽  
Hydrological Simulation

Abstract Investigating long-term streamflow changes pattern and its response to climate and human factors is of crucial significance to understand the hydrological cycle under a changing environment. Caijiazhuang catchment located within Haihe River basin, north China was selected as the study area. To detect the trend and changes in streamflow, Mann–Kendall test was used. Elasticity and hydrological simulation methods were applied to assess the relative contribution of climate change and human activities on streamflow variability under three periods (baseline (1958–1977), impact I (1978–1997), and impact II (1998–2012)). The long-term hydro-climatic variables experienced substantial changes during the whole study period, and 1977 was the breaking year of streamflow change. Attribution analysis using the two methods showed consistent results: for impact I, climate change impacts explained 65% and 68% of streamflow reduction; however for impact II, it only represented 49% and 56% of streamflow reduction. This result indicated that human activities were intensifying over time. Various types of human activities presented significant effects on streamflow regimes including volumes and hydrographs. The findings of this paper could provide better insights of hydrological evolution and would thus assist water managers in sustainably managing and providing water use strategies under a changing environment.

scholarly journals Flow distribution and trends in the Das Velhas River Basin

2019 ◽  
Vol 14 (3) ◽  
pp. 1
Author(s):  
Larissa Silva Melo ◽  
João Carlos Ferreira Borges Júnior ◽  
Ana Paula Coelho Madeira Silva
Keyword(s):  
Time Series ◽  
River Basin ◽  
Water Availability ◽  
Probability Distributions ◽  
River Mouth ◽  
Flow Distribution ◽  
Kendall Test ◽  
Daily Average ◽  
Quality Of Fit

In the management of water resources, it is necessary to balance the demands of multiple uses of water and water availability, while enabling use in an environmentally sustainable way. Probability distributions of flow rates are essential tools for assessing water availability. The objectives of this work were to analyze the best probability distribution that conforms to the annual minimum daily average discharge for periods of seven consecutive days (Q7) for 14 stream gauging stations in the Das Velhas River Basin and to identify possible trends in Q7 time series and in bi monthly and annual sets of daily discharges in three key stream gauging stations. The quality of fit was verified by the Anderson-Darling test (A-D). The selection of the models that presented the best fit was done according to the Bayesian Information Criterion (BIC). The Mann-Kendall test was used to verify trends in time series of discharge. In general, better measures of quality of fit were obtained for the probability distributions Gumbel and Rayleigh. Negative trends in discharge distributions were verified in the three stations. For the Várzea da Palma station, the closest to the river mouth, negative and significant trends were found for the Q7 data and daily average discharge for every bimester except the first.

scholarly journals Variability of Soil Erosion Intensity Due to Vegetation Cover Changes: Case Study of Orahovacka Rijeka, Montenegro

2018 ◽  
Vol 47 (1) ◽  
pp. 237-248 ◽  
Author(s):  
Gojko NIKOLIC ◽  
Velibor SPALEVIC ◽  
Milic CUROVIC ◽  
Abdulvahed KHALEDI DARVISHAN ◽  
Goran SKATARIC ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
River Basin ◽  
Vegetation Cover ◽  
Hydrological Cycle ◽  
Land Use Changes ◽  
National Level ◽  
River Basins ◽  
Surface Erosion ◽  
Erosion Intensity

Vegetation cover change in all the river basins leads to the changes of hydrologic response, soil erosion and sediment dynamics characteristics. Those changes are often viewed as main cause of anthropogenic and accelerated erosion rates in short term and one of the main reasons of climate change in long term. The effects of vegetation cover changes on various parts of water balance and hydrological cycle has to be deeply studied because of its important role on mankind future. The aim of present research was therefore to simulate the responses of soil erosion processes by using a process-oriented soil erosion model IntErO, with the different settings of land use for the years 1977, 1987, 1997, 2006 (2007) and 2016 (2017) in Orahovacka Rijeka watershed; a pilot river basin of the Polimlje Region for the northeastern part of Montenegro. For the current state of land use, calculated peak discharge for the Orahovacka Rijeka was 174-175 m3 s-1 (the incidence of 100 years) and there is a possibility for large flood waves to appear in the studied basin. Real soil losses, Gyear, were calculated on 2614-2921 m3 year-1, specific 229-256 m3 km-2 year-1 (1977-2017). The value of Z coefficient range from 0.444 to 0.478 and indicates that the river basin belongs to III destruction category. The strength of the erosion process is medium, and according to the erosion type, it is surface erosion. According to our analysis the land use changes in the last 40 years influenced the increase of the soil erosion intensity for 11% in the study watershed. Further studies should be focused on the detailed analysis of the land use changes trends with the other river basins at the national level, closely following responses of soil erosion to the changed land use structure. The results and approach also should be used by policymakers in all national natural resources organizations to highlight the role of management.

DEVELOPMENT OF STREAMFLOW DROUGHT INDICES IN THE MORAVA RIVER BASIN

2020 ◽  
Author(s):  
Ondrej Ledvinka ◽  
◽  
Pavel Coufal ◽  
Keyword(s):  
Time Series ◽  
Kendall Test ◽  
Drought Indices ◽  
Drought Period ◽  
Left Hand ◽  
Low Flows ◽  
Current Period ◽  
Catchment Size ◽  
Morava River ◽  
The Stability

The territory of Czechia currently suffers from a long-lasting drought period which has been a subject of many studies, including the hydrological ones. Previous works indicated that the basin of the Morava River, a left-hand tributary of the Danube, is very prone to the occurrence of dry spells. It also applies to the development of various hydrological time series that often show decreases in the amount of available water. The purpose of this contribution is to extend the results of studies performed earlier and, using the most updated daily time series of discharge, to look at the situation of the so-called streamflow drought within the basin. 46 water-gauging stations representing the rivers of diverse catchment size were selected where no or a very weak anthropogenic influences are expected and the stability and sensitivity of profiles allow for the proper measurement of low flows. The selected series had to cover the most current period 1981-2018 but they could be much longer, which was considered beneficial for the next determination of the development direction. Various series of drought indices were derived from the original discharge series. Specifically, 7-, 15- and 30-day low flows together with deficit volumes and their durations were tested for trends using the modifications of the Mann– Kendall test that account for short-term and long-term persistence. In order to better reflect the drivers of streamflow drought, the indices were considered for summer and winter seasons separately as well. The places with the situation critical to the future water resources management were highlighted where substantial changes in river regime occur probably due to climate factors. Finally, the current drought episode that started in 2014 was put into a wider context, making use of the information obtained by the analyses.

River-Basin Planning for Control of Nitrate Pollution

1982 ◽  
Vol 14 (4-5) ◽  
pp. 245-252 ◽  
Author(s):  
C S Sinnott ◽  
D G Jamieson
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
River Basin ◽  
Water Resource ◽  
Potable Water ◽  
Potential Problem ◽  
Nitrate Pollution ◽  
Optimal Mix ◽  
Regional Basis ◽  
The Impact

The combination of increasing nitrate concentrations in the River Thames and the recent EEC Directive on the acceptable level in potable water is posing a potential problem. In assessing the impact of nitrates on water-resource systems, extensive use has been made of time-series analysis and simulation. These techniques are being used to define the optimal mix of alternatives for overcoming the problem on a regional basis.

scholarly journals Superiority of Hybrid Soft Computing Models in Daily Suspended Sediment Estimation in Highly Dynamic Rivers

2021 ◽  
Vol 13 (2) ◽  
pp. 542
Author(s):  
Tarate Suryakant Bajirao ◽  
Pravendra Kumar ◽  
Manish Kumar ◽  
Ahmed Elbeltagi ◽  
Alban Kuriqi
Keyword(s):  
Time Series ◽  
Wavelet Transform ◽  
Suspended Sediment ◽  
River Basin ◽  
Time Series Data ◽  
Series Data ◽  
Discrete Wavelet ◽  
Original Time Series ◽  
Inference System ◽  
Original Time

Estimating sediment flow rate from a drainage area plays an essential role in better watershed planning and management. In this study, the validity of simple and wavelet-coupled Artificial Intelligence (AI) models was analyzed for daily Suspended Sediment (SSC) estimation of highly dynamic Koyna River basin of India. Simple AI models such as the Artificial Neural Network (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) were developed by supplying the original time series data as an input without pre-processing through a Wavelet (W) transform. The hybrid wavelet-coupled W-ANN and W-ANFIS models were developed by supplying the decomposed time series sub-signals using Discrete Wavelet Transform (DWT). In total, three mother wavelets, namely Haar, Daubechies, and Coiflets were employed to decompose original time series data into different multi-frequency sub-signals at an appropriate decomposition level. Quantitative and qualitative performance evaluation criteria were used to select the best model for daily SSC estimation. The reliability of the developed models was also assessed using uncertainty analysis. Finally, it was revealed that the data pre-processing using wavelet transform improves the model’s predictive efficiency and reliability significantly. In this study, it was observed that the performance of the Coiflet wavelet-coupled ANFIS model is superior to other models and can be applied for daily SSC estimation of the highly dynamic rivers. As per sensitivity analysis, previous one-day SSC (St-1) is the most crucial input variable for daily SSC estimation of the Koyna River basin.

Sign in / Sign up

Export Citation Format

Share Document