Investigating the Available Water for Irrigation in the Tana Basin, Kenya

2019 ◽  
pp. 44-51
Author(s):  
Alfred Opere
Keyword(s):  
Flow Analysis ◽  
Analysis Data ◽  
Environmental Flow ◽  
Base Flow ◽  
Low Flow ◽  
Available Water ◽  
Natural Flow ◽  
The Difference ◽  
Probability Methods ◽  
Standard Probability

The objective of this research paper was to establish water resources availability for agricultural production in Tana Basin. Frequency analysis techniques are used here to determine flood and low flow magnitudes required in the design of hydraulic structures affected by high and low flows. Generally, 80% probability of exceedance is recommended so that there is sufficient water, 4 out of 5 years. The 80% probable or available flow for irrigation purposes (flow exceeded in 4 out of 5 years) was obtained from analysis of river flows for RGS 4G01 using standard probability methods. The base flow or 30% of Q95 probable flow (also referred to as the environmental flow) was also computed. The available flow for irrigation is calculated from Q80 (also called the natural flow, as it is exceeded 4 out of 5 times in a year) and the environmental flow (Q95). Values of Q80, Q90 and Q95 are shown in table 2 under section 4. The difference between the environmental and natural flow gives the available water for irrigation. Kenyan regulations require that 30% of the Q95 base flow be considered as the environmental flow. The available water for irrigation is therefore calculated from equation 15. This formula is also called the water balance calculation for irrigation. Low flow analysis data has been presented for exceedance probabilities of 80 and 90% (Q80 and Q95). The Q80 flow is normally considered as the reliable flow for irrigation purposes. For Tana at Garissa, 4G01, the reliable flow varies from 35.7 cumecs in March to 122.6 cumecs in November. The available water is maximum in April-May when the demand is lowest.

scholarly journals Determination of Tank Model Parameters with Four Series Structure in Rokan Watershed

2019 ◽  
Vol 5 (2) ◽  
pp. 85-92
Author(s):  
Manyuk Fauzi ◽  
Yohanna Lilis Handayani ◽  
Annisa Destiany
Keyword(s):  
Water Resources ◽  
Water Availability ◽  
Flow Analysis ◽  
Daily Rainfall ◽  
Surface Flow ◽  
Base Flow ◽  
Low Flow ◽  
Model Parameters ◽  
Tank Model ◽  
Discharge Data

Information about low flow and water availability is one of the important factors in the management of water resources. The Rokan River Basin as one of the water resources in Riau Province is very important to know the condition of its water availability. One conceptual hydrological model for low flow analysis is the Tank Model developed by Sugawara. Data input needed in this research is daily rainfall data at Pasar Tangun Station, climatology data at Rambah Utama station and discharge data at AWLR Pasir Pengaraian. Model parameter search in the calibration stage is by trial and error. Using a 90% confidence interval a range of parameter values for the tank model is obtained, which is special for production store are surface flow 150.81 mm ≤ H1 ≤ 204.75 mm, intermediate flow 156.74 mm ≤ H2 ≤ 194.37 mm, sub base flow 141.24 mm ≤ H3 ≤ 176, 54 mm and base flow 139.43 mm ≤ H4 ≤ 176.12 mm.

PENGAKUAN CALABAI: SEBUAH ANALISIS INTERTEKSTUAL NOVEL PASUNG JIWA KARYA OKKY MADASARI DAN NOVEL CALABAI KARYA PEPI AL-BAYQUNIE

Jurnal KATA ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 50
Author(s):  
Krisna Aji Kusuma ◽  
Herman J Waluyo ◽  
Nugraheni Eko Wardani
Keyword(s):  
Content Analysis ◽  
Analysis Data ◽  
Qualitative Approach ◽  
The Novel ◽  
Research Results ◽  
Self Actualization ◽  
Similarities And Differences ◽  
The Difference ◽  
Descriptive Qualitative

<p><em>This study aims to describe the intertextuality relationship between the novel Pasung Jiwa by Okky Madasari and Calabai by Pepi Al-Bayqunie. The type of research is descriptive qualitative approach using content analysis. Data are collected by inventorying events that are similarities and differences, specifications on the characters, settings, plots, and themes of both text. The research results indicate that there are similar themes on the two novels, the theme of self actualization in addition with the theme of family and friendship. The same characterization are also used by both author, masculine figures with feminine soul characters. The difference between the two novels lies on the plot and setting. Pasung Jiwa uses progressive plot and Calabai uses a flash-back plot.. Okky Madasari takes Java Island as the background in the novel Pasung Jiwa, while the novel Calabai, Pepi Al-Bayqunie using the setting of Sulawesi Island. The basis of the similarity of theme and characterization supported by the similirity of events in the story shows the existence of intertextual relationship between the two novels. As a previously published work, the novel Pasung Jiwa by Okky Madasari is a hipogram and novel Calabai by Pepi A-Bayqunie as a transformational text. On the theme and characterization, the transformation of Calabai forward the hypogram, while in the plot and setting deviates his hypogram, Pasung Jiwa.</em></p><p>Penelitian ini bertujuan untuk mendeskripsikan hubungan intertekstualitas antara novel Pasung Jiwa karya Okky Madasari dan novel Calabai karya Pepi Al-Bayqunie. Jenis penelitian ini adalah deskriptif kualitatif dengan pendekatan konten analisis. Data dikumpulkan dengan menginventariskan peristiwa yang merupakan persamaan dan perbedaan, spesifikasi pada tokoh, latar, alur, dan tema dari kedua teks. Hasil penelitian ini menunjukkan bahwa terdapat kesamaan tema pada kedua novel, yaitu tema aktualisasi diri, ditambah dengan tema keluarga dan persahabatan. Penokohan yang sama juga digunakan oleh kedua penulis, yaitu tokoh maskulin dengan karakter jiwa feminin. Perbedaan kedua novel terletak pada alur dan latar. Pasung Jiwa menggunakan alur maju dan Calabai menggunakan alur campuran. Latar dalam novel Pasung Jiwa, Okky Madasari mengambil latar Pulau Jawa, sedangkan novel Calabai, Pepi Al-Bayqunie menggunakan latar Pulau Sulawesi. Dasar kesamaan tema dan penokohan didukung kesamaan peristiwa-peristiwa dalam cerita menunjukkan adanya hubungan intertekstual antara kedua novel. Sebagai karya yang terbit terlebih dahulu menjadikan novel Pasung Jiwa karya Okky Madasari adalah hipogram dan novel Calabai karya Pepi Al-Bayqunie sebagai teks transformasi. Pada tema dan penokohan, transformasi Calabai meneruskan hipogram, sedangkan pada alur dan latar menyimpangi hipogramnya, Pasung Jiwa.</p>

scholarly journals Regional differences in mortality rates during the COVID-19 epidemic in Italy

2020 ◽  
pp. 1-22
Author(s):  
Danila Azzolina ◽  
Giulia Lorenzoni ◽  
Luciano Silvestri ◽  
Ilaria Prosepe ◽  
Paola Berchialla ◽  
...  
Keyword(s):  
Regional Differences ◽  
Southern Italy ◽  
Meta Analysis ◽  
Analysis Data ◽  
Mortality Rates ◽  
Northern Italy ◽  
Admission Rates ◽  
Considerable Impact ◽  
The Difference ◽  
Disease Diffusion

Abstract Objective The COVID-19 outbreak started in Italy on February 20th, 2020, and has resulted in many deaths and intensive care unit (ICU) admissions. This study aimed to illustrate the epidemic COVID-19 growth pattern in Italy by considering the regional differences in disease diffusion during the first three months of the epidemic. Study design and methods Official COVID-19 data were obtained from the Italian Civil Protection Department of the Council of Ministers Presidency. The mortality and ICU admission rates per 100 000 inhabitants were calculated at the regional level and summarized via a Bayesian multilevel meta-analysis. Data were retrieved until April 21st, 2020. Results The highest cumulative mortality rates per 100 000 inhabitants were observed in northern Italy, particularly in Lombardia (85.3, 95% credibility intervals [CI] 75.7–94.7). The difference in the mortality rates between northern and southern Italy increased over time, reaching a difference of 67.72 (95% CI = 66–67) cases on April 2nd. Conclusions Northern Italy showed higher and increasing mortality rates during the first three months of the epidemic. The uncontrolled virus circulation preceding the infection spreading in southern Italy had a considerable impact on system burnout. This experience demonstrates that preparedness against the pandemic is of crucial importance to contain its disruptive effects.

scholarly journals Estimation of recharge in mountain hard-rock aquifers based on discrete spring discharge monitoring during base-flow recession

2021 ◽  
Author(s):  
Stefano Segadelli ◽  
Maria Filippini ◽  
Anna Monti ◽  
Fulvio Celico ◽  
Alessandro Gargini
Keyword(s):  
Hard Rock ◽  
Monitoring Program ◽  
Base Flow ◽  
Low Flow ◽  
Reliable Estimate ◽  
Spring Discharge ◽  
Aquifer Recharge ◽  
Clear Cut ◽  
Groundwater Circulation ◽  
Hard Rock Aquifers

AbstractEstimation of aquifer recharge is key to effective groundwater management and protection. In mountain hard-rock aquifers, the average annual discharge of a spring generally reflects the vertical aquifer recharge over the spring catchment. However, the determination of average annual spring discharge requires expensive and challenging field monitoring. A power-law correlation was previously reported in the literature that would allow quantification of the average annual spring discharge starting from only a few discharge measurements in the low-flow season, in a dry summer climate. The correlation is based upon the Maillet model and was previously derived by a 10-year monitoring program of discharge from springs and streams in hard-rock aquifers composed of siliciclastic and calcareous turbidites that did not have well defined hydrogeologic boundaries. In this research, the same correlation was applied to two ophiolitic (peridotitic) hard-rock aquifers in the Northern Apennines (Northern Italy) with well-defined hydrogeologic boundaries and base-outflow springs. The correlation provided a reliable estimate of the average annual spring discharge thus confirming its effectiveness regardless of bedrock lithology. In the two aquifers studied, the measurable annual outputs (i.e. sum of average annual spring discharges) could be assumed equal to the annual inputs (i.e. vertical recharge) based on the clear-cut aquifer boundaries and a quick groundwater circulation inferable from spring water parameters. Thus, in such setting, the aforementioned correlation also provided an estimate of the annual aquifer recharge allowing the assessment of coefficients of infiltration (i.e. ratio between aquifer recharge and total precipitation) ranging between 10 and 20%.

Experimental and Computational Analyses of Pressure Differentials in Flexible Ducts With Different Bent Angles

2007 ◽  
Author(s):  
Ray R. Taghavi ◽  
Wonjin Jin ◽  
Mario A. Medina
Keyword(s):  
Pressure Drop ◽  
Static Pressure ◽  
Complex Geometry ◽  
Analysis Data ◽  
Secondary Flows ◽  
Low Flow ◽  
Pressure Drops ◽  
Pressure Distributions ◽  
Geometrical Effects ◽  
Cfd Analyses

A set of experimental analyses was conducted to determine static pressure drops inside non-metallic flexible, spiral wire helix core ducts, with different bent angles. In addition, Computational Fluid Dynamics (CFD) solutions were performed and verified by comparing them to the experimental data. The CFD computations were carried out to produce more systematic pressure drop information through these complex-geometry ducts. The experimental setup was constructed according to ASHRAE Standard 120-1999. Five different bent angles (0, 30, 45, 60, and 90 degrees) were tested at relatively low flow rates (11 to 89 CFM). Also, two different bent radii and duct lengths were tested to study flexible duct geometrical effects on static pressure drops. FLUENT 6.2, using RANS based two equations - RNG k-ε model, was used for the CFD analyses. The experimental and CFD results showed that larger bent angles produced larger static pressure drops in the flexible ducts. CFD analysis data were found to be in relatively good agreement with the experimental results for all bent angle cases. However, the deviations became slightly larger at higher velocity regimes and at the longer test sections. Overall, static pressure drop for longer length cases were approximately 0.01in.H2O higher when compared to shorter cases because of the increase in resistance to the flow. Also, the CFD simulations captured more pronounced static pressure drops that were produced along the sharper turns. The stronger secondary flows, which resulted from higher and lower static pressure distributions in the outer and inner surfaces, respectively, contributed to these higher pressure drops.

scholarly journals The European 2015 drought from a hydrological perspective

2017 ◽  
Vol 21 (6) ◽  
pp. 3001-3024 ◽  
Author(s):  
Gregor Laaha ◽  
Tobias Gauster ◽  
Lena M. Tallaksen ◽  
Jean-Philippe Vidal ◽  
Kerstin Stahl ◽  
...  
Keyword(s):  
Water Cycle ◽  
Hydrological Drought ◽  
Low Flow ◽  
Drought Indices ◽  
Climate Indices ◽  
Climate Data ◽  
Spatial And Temporal Scales ◽  
Space And Time ◽  
Dynamic Development ◽  
The Difference

Abstract. In 2015 large parts of Europe were affected by drought. In this paper, we analyze the hydrological footprint (dynamic development over space and time) of the drought of 2015 in terms of both severity (magnitude) and spatial extent and compare it to the extreme drought of 2003. Analyses are based on a range of low flow and hydrological drought indices derived for about 800 streamflow records across Europe, collected in a community effort based on a common protocol. We compare the hydrological footprints of both events with the meteorological footprints, in order to learn from similarities and differences of both perspectives and to draw conclusions for drought management. The region affected by hydrological drought in 2015 differed somewhat from the drought of 2003, with its center located more towards eastern Europe. In terms of low flow magnitude, a region surrounding the Czech Republic was the most affected, with summer low flows that exhibited return intervals of 100 years and more. In terms of deficit volumes, the geographical center of the event was in southern Germany, where the drought lasted a particularly long time. A detailed spatial and temporal assessment of the 2015 event showed that the particular behavior in these regions was partly a result of diverging wetness preconditions in the studied catchments. Extreme droughts emerged where preconditions were particularly dry. In regions with wet preconditions, low flow events developed later and tended to be less severe. For both the 2003 and 2015 events, the onset of the hydrological drought was well correlated with the lowest flow recorded during the event (low flow magnitude), pointing towards a potential for early warning of the severity of streamflow drought. Time series of monthly drought indices (both streamflow- and climate-based indices) showed that meteorological and hydrological events developed differently in space and time, both in terms of extent and severity (magnitude). These results emphasize that drought is a hazard which leaves different footprints on the various components of the water cycle at different spatial and temporal scales. The difference in the dynamic development of meteorological and hydrological drought also implies that impacts on various water-use sectors and river ecology cannot be informed by climate indices alone. Thus, an assessment of drought impacts on water resources requires hydrological data in addition to drought indices based solely on climate data. The transboundary scale of the event also suggests that additional efforts need to be undertaken to make timely pan-European hydrological assessments more operational in the future.

scholarly journals Dominant Fish and Macroinvertebrate Response to Flow Changes of the Geum River in Korea

Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 942 ◽  
Author(s):  
Hyeongsik Kang ◽  
Byungwoong Choi
Keyword(s):  
Flow Patterns ◽  
Base Flow ◽  
Physical Habitat ◽  
Aquatic Species ◽  
Morphology Change ◽  
Suitability Index ◽  
Natural Flow ◽  
Habitat Simulation ◽  
Target Fish ◽  
The Impact

This study presents the impact of natural flow patterns on downstream aquatic species habitats in a reach of the Geum River, Korea. The study reach is a 13.4 km long, located downstream of the Yongdam Dam. To assess such an impact, this study performed physical habitat simulations. The River2D model was used for the computation of the flow field and morphology, and the Habitat Suitability Index (HSI) model for the habitat simulation. Three habitat variables—flow depth, velocity, and substrate were used. The Zacco platypus and Baetis fuscatus were selected as the target fish and benthic macro-invertebrate, respectively. Using the building block approach (BBA), the scenarios for modifying dam operations were constructed in the study reach. Scenario 1, scenario 2, and scenario 3 were proposed by using the magnitude–duration concept, base flow allocation concept, and seasonally adjusted minimum flow allocation concept, respectively. Simulation results indicated that the scenarios’ effects significantly increased by about 14.3% for the weighted usable area (WUA). In addition, the morphology change with the restoration of flood events was investigated. It was revealed that the morphology change in the physical habitat simulations further increased by about 13% for the WUA. The change of dam operations through natural flow patterns is more advantageous to aquatic species.

Unruptured intracranial aneurysms and arteriovenous malformations: frequency of intracranial hemorrhage and relationship of lesions

1990 ◽  
Vol 73 (6) ◽  
pp. 859-863 ◽  
Author(s):  
Robert D. Brown ◽  
David O. Wiebers ◽  
Glenn S. Forbes
Keyword(s):  
Intracranial Hemorrhage ◽  
Arteriovenous Malformations ◽  
Low Flow ◽  
Content Type ◽  
Unruptured Intracranial Aneurysms ◽  
The Difference ◽  
Arterial Feeder ◽  
Relationship Of ◽  
The Relationship ◽  
Feeding Systems

✓ Among 91 patients with unruptured intracranial arteriovenous malformations (AVM's), 16 patients had 26 unruptured intracranial saccular aneurysms. An actuarial analysis showed the risk of intracranial hemorrhage among patients with coexisting aneurysm and AVM to be 7% per year at 5 years following diagnosis compared to 1.7% for patients with AVM alone. The difference in length of survival free of hemorrhage was significant (log-rank, p < 0.0007). Several angiographic and clinical parameters were investigated to better understand the relationship of these lesions. The aneurysms occurred in similar percentages in patients with small, medium, and large AVM's. Twenty-five aneurysms were on arteries feeding the malformation system, almost equally distributed proximally and distally. Eleven aneurysms were atypical in location, and all arose from primary or secondary branch feeders to the malformation; 24 were on enlarged feeding arteries. Eleven (16%) of the 67 patients with high-flow AVM's had associated aneurysms, compared with five (21%) of the 24 patients with low-flow AVM's. Four (16%) of 25 low-shunt malformations and 12 (18%) of 65 high-shunt malformations had associated aneurysms. All five aneurysms associated with low-shunt malformations were on a direct arterial feeder of the malformation. These data suggest that the intracranial AVM's predispose to aneurysm formation within AVM feeding systems and that the mechanism is not simply based upon the high blood flow or high arteriovenous shunt in these systems.

scholarly journals Estimating the Relative Uncertainties Sourced from GCMs and Hydrological Models in Modeling Climate Change Impact on Runoff

2012 ◽  
Vol 13 (1) ◽  
pp. 122-139 ◽  
Author(s):  
Jin Teng ◽  
Jai Vaze ◽  
Francis H. S. Chiew ◽  
Biao Wang ◽  
Jean-Michel Perraud
Keyword(s):  
Climate Change ◽  
Climate Change Impact ◽  
Daily Rainfall ◽  
Low Flow ◽  
Hydrological Models ◽  
Rainfall Runoff ◽  
Runoff Modeling ◽  
Change Impact ◽  
The Difference ◽  
Climate Series

Abstract This paper assesses the relative uncertainties from GCMs and from hydrological models in modeling climate change impact on runoff across southeast Australia. Five lumped conceptual daily rainfall–runoff models are used to model runoff using historical daily climate series and using future climate series obtained by empirically scaling the historical climate series informed by simulations from 15 GCMs. The majority of the GCMs project a drier future for this region, particularly in the southern parts, and this is amplified as a bigger reduction in the runoff. The results indicate that the uncertainty sourced from the GCMs is much larger than the uncertainty in the rainfall–runoff models. The variability in the climate change impact on runoff results for one rainfall–runoff model informed by 15 GCMs (an about 28%–35% difference between the minimum and maximum results for mean annual, mean seasonal, and high runoff) is considerably larger than the variability in the results between the five rainfall–runoff models informed by 1 GCM (a less than 7% difference between the minimum and maximum results). The difference between the rainfall–runoff modeling results is larger in the drier regions for scenarios of big declines in future rainfall and in the low-flow characteristics. The rainfall–runoff modeling here considers only the runoff sensitivity to changes in the input climate data (primarily daily rainfall), and the difference between the hydrological modeling results is likely to be greater if potential changes in the climate–runoff relationship in a warmer and higher CO2 environment are modeled.

scholarly journals Multiple causes of nonstationarity in the Weihe annual low-flow series

2018 ◽  
Vol 22 (2) ◽  
pp. 1525-1542 ◽  
Author(s):  
Bin Xiong ◽  
Lihua Xiong ◽  
Jie Chen ◽  
Chong-Yu Xu ◽  
Lingqi Li
Keyword(s):  
Frequency Analysis ◽  
Driving Forces ◽  
Potential Evapotranspiration ◽  
Aridity Index ◽  
Base Flow ◽  
Low Flow ◽  
Distribution Model ◽  
Flow Index ◽  
Explanatory Variables ◽  
Distribution Parameters

Abstract. Under the background of global climate change and local anthropogenic activities, multiple driving forces have introduced various nonstationary components into low-flow series. This has led to a high demand on low-flow frequency analysis that considers nonstationary conditions for modeling. In this study, through a nonstationary frequency analysis framework with the generalized linear model (GLM) to consider time-varying distribution parameters, the multiple explanatory variables were incorporated to explain the variation in low-flow distribution parameters. These variables are comprised of the three indices of human activities (HAs; i.e., population, POP; irrigation area, IAR; and gross domestic product, GDP) and the eight measuring indices of the climate and catchment conditions (i.e., total precipitation P, mean frequency of precipitation events λ, temperature T, potential evapotranspiration (EP), climate aridity index AIEP, base-flow index (BFI), recession constant K and the recession-related aridity index AIK). This framework was applied to model the annual minimum flow series of both Huaxian and Xianyang gauging stations in the Weihe River, China (also known as the Wei He River). The results from stepwise regression for the optimal explanatory variables show that the variables related to irrigation, recession, temperature and precipitation play an important role in modeling. Specifically, analysis of annual minimum 30-day flow in Huaxian shows that the nonstationary distribution model with any one of all explanatory variables is better than the one without explanatory variables, the nonstationary gamma distribution model with four optimal variables is the best model and AIK is of the highest relative importance among these four variables, followed by IAR, BFI and AIEP. We conclude that the incorporation of multiple indices related to low-flow generation permits tracing various driving forces. The established link in nonstationary analysis will be beneficial to analyze future occurrences of low-flow extremes in similar areas.

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