scholarly journals Variabilities and Trends of Rainfall, Temperature, and River Flow in Sipi Sub-Catchment on the Slopes of Mt. Elgon, Uganda

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1834
Author(s):  
Justine Kilama Luwa ◽  
Jackson-Gilbert Mwanjalolo Majaliwa ◽  
Yazidhi Bamutaze ◽  
Isa Kabenge ◽  
Petter Pilesjo ◽  
...  
Keyword(s):  
Land Use ◽  
Trend Analysis ◽  
Coefficient Of Variation ◽  
River Flow ◽  
Land Use Changes ◽  
Standardized Precipitation Index ◽  
Daily Rainfall ◽  
Annual Rainfall ◽  
Slope Estimator ◽  
The Standardized Precipitation Index

The variabilities in rainfall and temperature in a catchment affect water availability and sustainability. This study assessed the variabilities in rainfall and temperature (1981–2015) and river flow (1998–2015) in the Sipi sub-catchment on annual and seasonal scales. Observed daily rainfall and temperature data for Buginyanya and Kapchorwa weather stations were obtained from the Uganda National Meteorological Authority (UNMA), while the daily river-flow data for Sipi were obtained from the Ministry of Water and Environment (MWE). The study used descriptive statistics, the Standardized Precipitation Index (SPI), Mann–Kendall trend analysis, and Sen’s slope estimator. Results indicate a high coefficient of variation (CV) (CV > 30) for August, September, October, and November (ASON) seasonal rainfall, while annual rainfall had a moderate coefficient of variation (20 ˂ CV ˂ 30). The trend analysis shows that ASON minimum and mean temperatures increased at α = 0.001 and α = 0.05 levels of significance respectively in both stations and over the entire catchment. Furthermore, annual and March, April, and May (MAM) river flows increased at an α = 0.05 level of significance. A total of 14 extremely wet and dry events occurred in the sub-catchment during the post-2000 period, as compared to five in the pre-2000. The significant increased trend of river flow could be attributed to the impacts of climate and land-use changes. Therefore, future studies may need to quantify the impacts of future climate and land-use changes on water resources in the sub-catchment.

scholarly journals Rainfall Trend Analysis in Tehsils of Palghar District, Maharashtra State, India

2021 ◽  
Vol 9 (11) ◽  
pp. 238-253
Author(s):  
Dr. Sumit M. Dhak
Keyword(s):  
Trend Analysis ◽  
Linear Trend ◽  
Daily Rainfall ◽  
Kendall Test ◽  
Rainfall Data ◽  
Annual Rainfall ◽  
Rainfall Trend ◽  
Department Of Agriculture ◽  
Increasing Trend ◽  
Slope Estimator

Abstract: A detailed trend analysis of monthly and annual rainfall for Tehsils of Palghar district were carried out using 22 years (1998-2019) daily rainfall data taken from Department of Agriculture, Maharashtra State. In this study, to analyse the trend, the non-parametric test (Mann-Kendall test) and Sen’s slope estimator were used. For developing a functional relationship between variables, a linear trend of rainfall data for the studied area evaluated using the linear regression. The results showed that the trend analysis of monthly rainfall has a varied trend of rainfall in the rainy months in tehsil of Palghar District. The month of July significant increasing trend was observed at Jawhar (42.91 mm/year), Vikramgad (29.90 mm/year), Wada (24.06 mm/year), Talasari (31.36 mm/year), Palghar (25.299 mm/year), Mokhada (29.96 mm/year) and Dahanu (38.14 mm/year), whereas non-significant increasing trend 2.76 mm/year was observed at Vasai tehsil of Palghar District during 1998-2019. The month of June, August, September and October rainfall did not show any significant trend in tehsil of Palghar District and non significant decreasing as well as non significant increasing trend was observed in tehsil of Palghar District during 1998 – 2019. The result concluded that annual rainfall trend was increased in Jawhar, Vikramgad, Wada, Talasari, Palghar, Mokhada and Dahanu; whereas Vasai tehsil rainfall trend was decreased in tehsil of Palghar District during 1998 -2019. Keywords: Rainfall, Trend Analysis, Mann Kendall’s Test, Sen Slopes, Regression

scholarly journals Standardized Precipitation Index Comparison along the Limbe-Bamenda Axis of the Cameroon Gulf of Guinea

2021 ◽  
Vol 3 (1) ◽  
pp. 1-1
Author(s):  
Suiven John Paul Tume ◽  
Keyword(s):  
Coefficient Of Variation ◽  
Rainfall Variability ◽  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Annual Rainfall ◽  
Environment Interaction ◽  
Ecological Zones ◽  
Mean Annual Rainfall ◽  
The Mean ◽  
The Standardized Precipitation Index

Mean monthly rainfall decline with continentality is a commonplace phenomenon that has been used in this study to compare its trend in Bamenda in the Western Highlands and Limbe on the Atlantic lowland coast. This study attempts to bridge some of the methodological gaps in the previous studies on rainfall variability in Cameroon that had emphasized only the inter-annual variability and coefficient of variation without focusing on the specific indices and contrasts between different ecological zones. In this study, a comparative analysis has been done of the standardized precipitation index (SPI) for Bamenda and Limbe, using data from 1985–2015. The analysis involved the mean annual rainfall (176.88 mm and 419.9 mm), its standard deviation (SD) (22.98 and 102.42), and the coefficient of variation (CV) (12.99% and 24.41%) for Bamenda and Limbe, respectively. The results show that the mean annual rainfall for Bamenda is decreasing, whereas that of Limbe is increasing. The mean SPI is –0.01 (mild dryness) and 0.02 (mild wetness) for Bamenda and Limbe, respectively. These results have far-reaching implications for the development of agriculture, water resources management, and other man-environment interaction variants.

Changes in discharge rise and fall rates applied to impact assessment of catchment land use

2009 ◽  
Vol 41 (1) ◽  
pp. 13-26 ◽  
Author(s):  
D. R. Archer ◽  
D. Climent-Soler ◽  
I. P. Holman
Keyword(s):  
Land Use ◽  
River Flow ◽  
Land Use Changes ◽  
Daily Rainfall ◽  
Short Term ◽  
Rates Of Change ◽  
Fall Rates ◽  
Potential Basis ◽  
Management Policies ◽  
Land Use And Management

Despite substantial evidence that land use and management can enhance flood runoff at a local scale, evidence of increased flood risk based on peak discharges is lacking in catchments greater than 10 km2. This analysis is instead based on assessing changes in short-term rates of change in discharge. The influence of land use is demonstrated first on the small Coalburn catchment where changes in rates of rise are closely related to drainage and afforestation. For the larger Axe catchment (288 km2), changes in rates of rise are investigated by comparing annual maximum and peaks over a threshold flows for different periods, by comparing rates of rise associated with given daily rainfall and by adapting the method of flow variability analysis for use of rates of change rather than flow itself. All these methods demonstrate significant changes in river flow dynamics which seem to be in parallel with land use changes even when the influence of climate variability from year to year has been taken into account. Rates of change in discharge appear to respond to land use changes and thus provide a potential basis for application to land use management policies.

scholarly journals A Model-Based Tool for Assessing the Impact of Land Use Change Scenarios on Flood Risk in Small-Scale River Systems—Part 1: Pre-Processing of Scenario Based Flood Characteristics for the Current State of Land Use

Hydrology ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 102
Author(s):  
Frauke Kachholz ◽  
Jens Tränckner
Keyword(s):  
Land Use ◽  
River Flow ◽  
Land Use Changes ◽  
Small Rivers ◽  
Small Scale ◽  
Model Parameters ◽  
Ungauged Catchments ◽  
Model Based ◽  
Current State ◽  
The Impact

Land use changes influence the water balance and often increase surface runoff. The resulting impacts on river flow, water level, and flood should be identified beforehand in the phase of spatial planning. In two consecutive papers, we develop a model-based decision support system for quantifying the hydrological and stream hydraulic impacts of land use changes. Part 1 presents the semi-automatic set-up of physically based hydrological and hydraulic models on the basis of geodata analysis for the current state. Appropriate hydrological model parameters for ungauged catchments are derived by a transfer from a calibrated model. In the regarded lowland river basins, parameters of surface and groundwater inflow turned out to be particularly important. While the calibration delivers very good to good model results for flow (Evol =2.4%, R = 0.84, NSE = 0.84), the model performance is good to satisfactory (Evol = −9.6%, R = 0.88, NSE = 0.59) in a different river system parametrized with the transfer procedure. After transferring the concept to a larger area with various small rivers, the current state is analyzed by running simulations based on statistical rainfall scenarios. Results include watercourse section-specific capacities and excess volumes in case of flooding. The developed approach can relatively quickly generate physically reliable and spatially high-resolution results. Part 2 builds on the data generated in part 1 and presents the subsequent approach to assess hydrologic/hydrodynamic impacts of potential land use changes.

scholarly journals Modelling monthly runoff generation processes following land use changes: groundwater–surface runoff interactions

2004 ◽  
Vol 8 (5) ◽  
pp. 903-922 ◽  
Author(s):  
M. Bari ◽  
K. R. J. Smettem
Keyword(s):  
Land Use ◽  
Water Balance ◽  
Surface Runoff ◽  
Land Use Changes ◽  
Annual Rainfall ◽  
Rainfall Runoff ◽  
Runoff Generation ◽  
Mean Annual Rainfall ◽  
Monthly Runoff ◽  
Stream Bed

Abstract. A conceptual water balance model is presented to represent changes in monthly water balance following land use changes. Monthly rainfall–runoff, groundwater and soil moisture data from four experimental catchments in Western Australia have been analysed. Two of these catchments, "Ernies" (control, fully forested) and "Lemon" (54% cleared) are in a zone of mean annual rainfall of 725 mm, while "Salmon" (control, fully forested) and "Wights" (100% cleared) are in a zone with mean annual rainfall of 1125 mm. At the Salmon forested control catchment, streamflow comprises surface runoff, base flow and interflow components. In the Wights catchment, cleared of native forest for pasture development, all three components increased, groundwater levels rose significantly and stream zone saturated area increased from 1% to 15% of the catchment area. It took seven years after clearing for the rainfall–runoff generation process to stabilise in 1984. At the Ernies forested control catchment, the permanent groundwater system is 20 m below the stream bed and so does not contribute to streamflow. Following partial clearing of forest in the Lemon catchment, groundwater rose steadily and reached the stream bed by 1987. The streamflow increased in two phases: (i) immediately after clearing due to reduced evapotranspiration, and (ii) through an increase in the groundwater-induced stream zone saturated area after 1987. After analysing all the data available, a conceptual monthly model was created, comprising four inter-connecting stores: (i) an upper zone unsaturated store, (ii) a transient stream zone store, (ii) a lower zone unsaturated store and (iv) a saturated groundwater store. Data such as rooting depth, Leaf Area Index, soil porosity, profile thickness, depth to groundwater, stream length and surface slope were incorporated into the model as a priori defined attributes. The catchment average values for different stores were determined through matching observed and predicted monthly hydrographs. The observed and predicted monthly runoff for all catchments matched well with coefficients of determination (R2) ranging from 0.68 to 0.87. Predictions were relatively poor for: (i) the Ernies catchment (lowest rainfall, forested), and (ii) months with very high flows. Overall, the predicted mean annual streamflow was within ±8% of the observed values. Keywords: monthly streamflow, land use change, conceptual model, data-based approach, groundwater

scholarly journals ARAHAN PENGGUNAAN LAHAN DAN PERENCANAAN KONSERVASI TANAH DAN AIR DI DAS YEH EMPAS, TABANAN, BALI

2015 ◽  
Vol 9 (1) ◽  
pp. 54
Author(s):  
I Gusti Agung Lanang Widyantara ◽  
I Nyoman Merit ◽  
I Wayan Sandi Adnyana
Keyword(s):  
Land Use ◽  
Land Use Planning ◽  
Land Use Changes ◽  
Daily Rainfall ◽  
Research Area ◽  
High Density ◽  
Scoring Method ◽  
Management Actions ◽  
Erosion Prediction ◽  
Slope Factor

Damage to forest resources has caused the environmental balance of watersheds (DAS) becomes damaged. It often causes the result of high levels of erosion. One of the land use changes that are currently happening is in Yeh Empas watershed. With this research can be known the proposed land use and appropriate land use planning on Yeh Empas watershed. Erosion prediction using the USLE (Universal Soil Loss Equation) method is to estimate how much the rate of erosion is happening and also to get an idea how good land management actions for the region. The proposed land use determination is using the scoring method by combining the slope factor of the field, the soil sensitivity of erosion, and the intensity of daily rainfall. Soil sampling was done by taking soil samples from a total of 11 samples of soil from the land unit. This research conducted to estimate the rate of erosion, to determines how much erosion can be tolerated in Yeh Empas watershed, and its relationship with the factors that influence it, as well as to determine the proposed of land use. The results of erosion prediction on each unit of land in the research area ranged from 1.75 to 1,254.96 tons/ha/year and has a grade level of erosion from slight to very severe. The result of tolerated erosion ranged from 15.06 to 24.32 tons/ha/year. The value of erosion prediction that exceeded from tolerated erosion value occurs on land units 7, 8, and 9. On that land units required proposed of land use and soil conservation techniques so that the value of erosion prediction could be below from tolerated erosion value. The analysis results of the proposed land use in Yeh Empas watershed, for areas inside the forest is proposed to protected forest (land units 1, 2, 3, 4, 5, and 6) and the management is by planting plants that are adapted to the contour lines of slope. In the areas outside the forest is proposed for annual crop cultivation area (land units 7, 8, and 9)the management with the farming plantation development, high density growing crops and terracing and also for crops cultivation area (land units 10 and 11) management by mulching, cover soil with high density and terracing.

scholarly journals LOW COST POTENTIAL INFILTRATION ESTIMATION FOR WET TROPICAL WATERSHEDS FOR TERRITORIAL PLANNING SUPPORT

2017 ◽  
Vol 10 (2) ◽  
pp. 233-241
Author(s):  
Franciane Mendonça Dos Santos ◽  
José Augusto Lollo
Keyword(s):  
Land Use ◽  
Soil Conservation ◽  
Low Cost ◽  
Land Use Changes ◽  
Mass Movement ◽  
Curve Number ◽  
Annual Rainfall ◽  
Soil Conservation Service ◽  
Local Conditions ◽  
Territorial Planning

This study was developed at Caçula stream watershed of Ilha Solteira (Brazil) for potential infiltration estimation based on digital cartography. These methods aim at low-cost and quick analysis processes in order to support the territorial planning. The preliminary potential infiltration chart was produced using ArcHydro and pedological information of the study area. The curve-number method (Soil Conservation Service) was used to determine the potential infiltration combining information related to land-use and soil types in the watershed. We also used a methodology that assumes being possible to evaluate potential infiltration of a watershed combining average annual rainfall, land-use and watershed natural attributes (geomorphology, geology and pedology). Results show that ArcHydro is efficient for a preliminary characterization because it shows flow accumulation areas, allowing higher potential of degradation areas in terms of floods, mass movement and erosion. As land-use classes have significant weight in Soil Conservation Service method assessing potential infiltration, this method allow us to evaluate how land-use changes affect water dynamic in the watershed. The propose based on natural environment attributes enables to determine the homologous infiltration areas based on a higher number of natural characteristics of the area, and thereby obtain a result that is closer to the local conditions and, consequently for degradation surface processes identification.

Land use changes and hydrological trend analysis in a Brazilian Cerrado basin

2021 ◽  
Author(s):  
L. L. Ferraz ◽  
L. F. de Sousa ◽  
L. S. da Silva ◽  
R. M. de Jesus ◽  
C. A. S. Santos ◽  
...  
Keyword(s):  
Land Use ◽  
Trend Analysis ◽  
Land Use Changes ◽  
Brazilian Cerrado

scholarly journals Impacts of groundwater over exploitation on the renewal and hydrodynamic behavior of the alluvial aquifer of Sidi Bel Abbes (Algerian NW)

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Abdelkader Otmane ◽  
Kamila Baba-Hamed ◽  
Abderrazak Bouanani ◽  
Radia Gherissi
Keyword(s):  
Water Potential ◽  
Agricultural Sector ◽  
Standardized Precipitation Index ◽  
Alluvial Aquifer ◽  
Annual Rainfall ◽  
Drainage Flows ◽  
Large Water ◽  
Over Exploitation ◽  
The Standardized Precipitation Index ◽  
Hydrodynamic Data

AbstractSidi Bel Abbes plain, in Western Algeria, covers an area of 813 km2 and holds an important groundwater reservoir, providing the region with a large water potential. It displays characteristics of a peri-urban aquifer, with a large agricultural sector. The climatic variations that affected this region, the development of industrial and agricultural activities along with the over-exploitation of the groundwater resource negatively impact the aquifer's hydrodynamic balance. This work is structured around a multiapproach process based mainly on geophysical data to determine the reservoir bathymetry, rainfall data, humidity data using the standardized precipitation index (SPI), piezometric maps, hydrodynamic data, and groundwater extraction rate. Results revealed a significant decrease in humidity values over time. This negatively influences the water potential of the alluvial aquifer and induces a lateral recharge from adjacent aquifers (overfilling). Indeed, the rainfall contribution to the recharge appears low compared to that of the surrounding aquifers. However, total annual rainfall above 500 mm/year may reduce the input of the adjacent aquifers. Besides, our study indicates a well-defined hydrodynamic pattern in the alluvial aquifer, due to the bowl-shaped bedrock of the aquifer and the excessive overexploitation, especially downstream (the region of Sidi Bel Abbes). Thus, this aquifer adapted to such exploitation, through continuous and systematic recharge of drainage flows by the upstream groundwater (regions characterized by a wall uplift). The aquifer’s pluviometric dependence occurs clearly in its south-western part. A 50% humidity value implies a 0–10 m increase in the water table.

scholarly journals Trend Analysis of Annual and Monthly Rainfall in Erbil City, Kurdistan Region, Iraq

2019 ◽  
Vol 9 (2) ◽  
pp. 30-36 ◽  
Author(s):  
Saud A. Hussien ◽  
Basil Y. Mustafa ◽  
Farzand K. Medhat
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Trend Analysis ◽  
Linear Regression Analysis ◽  
Monthly Rainfall ◽  
Annual Rainfall ◽  
Sen’S Slope Estimator ◽  
Sen’S Slope ◽  
Slope Estimator ◽  
Non Parametric

The objective of this study is to identify the trend for the annual and monthly rainfall time series data from 1963–1964 to 2018–2019 for Erbil city rainfall gauging station. The trend analysis was conducted for only rainy months (from October to May) using the non-parametric Mann-Kendall test, whereas a non-parametric Sen’s slope estimator was used to determine the magnitude of the trend. A functional relationship has been developed between variables using linear regression analysis to determine a linear trend of rainfall for the study area. The annual trend analysis revealed negative (decreasing) trend because the Kendall’s tau (Z) value and the Sen’s slope estimator magnitude were both negative and found to be −0.093 and −1.37, respectively, and the slope of the linear regression analysis was also negative and equal to −0.9148 mm/year, which represents the rate of yearly annual rainfall decreasing trend. Considering the result of monthly rainfall, the trend analysis of rainfall has suggested that there is a trend variation of rainfall in the rainy months. Further, the analysis revealed a negative (decreasing) trend for months November, January, February, March, April, and May and positive (increasing) trend for months October and December. This study is important as it greatly contributes in water resources system planning and management in this region. Furthermore, the results obtained in this work are promising and might help hydraulic civil and water resource engineers in the design of hydraulic structures.

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