scholarly journals Evaluation of Hydraulic Performance On Lower Areb Small Scale Irrigation Scheme Amhara, Ethiopia

2021 ◽  
Author(s):  
Gashaw Sintayehu Angualie ◽  
Alemshet Belayneh ◽  
Kibru Gedam Berhanu ◽  
Tirunesh Muluken Munye ◽  
Kefale Ejigu ◽  
...  
Keyword(s):  
Physical Performance ◽  
Performance Indicators ◽  
Water Surface ◽  
Hydraulic Performance ◽  
Water Infiltration ◽  
Surface Elevation ◽  
Small Scale ◽  
Irrigation Scheme ◽  
Water Surface Elevation ◽  
Small Scale Irrigation

Abstract This study was conducted in the Lower Areb small-scale irrigation scheme for one crop season from March to May 2018 to evaluate the hydraulic performance of the scheme by estimating the hydraulic performance indicators, physical performance indicators, and maintenance performance indicators. The primary data including water flow rate, soil physical properties, and water infiltration were collected. The secondary data collected were climatic, crop data, and data from different reports and design documents including the irrigation water users' interviews. The hydraulic performance of the irrigation scheme was evaluated by estimating adequacy, efficiency, dependability, and equity indicators at nine selected offtakes; three each at the head, middle, and tail reaches of the scheme. The physical performance and maintenance indicators were determined using the irrigation ratio, the sustainability of the irrigated area, the effectiveness of infrastructure, and the water surface elevation ratio. The data were analyzed by using CROPWAT 8.0, ARC GIS 10.1 software, and Microsoft Excel 2013. The overall average values of adequacy, efficiency, dependability, and equity were found to be 0.89. 0.91, 0.096 and 0.07 respectively. Therefore, dependability, equity, and efficiency were under good condition and adequacy was under fair condition. The irrigation ratio and sustainability of irrigated areas were 54% and 123% respectively. The effectiveness of infrastructure and water surface elevation ratios were 73.33% and 94% respectively.

scholarly journals Hydraulic Performance Assessment of Mychew Small Scale Irrigation Scheme, North Ethiopia

2019 ◽  
pp. 549-561
Author(s):  
Efriem Tariku Kassa ◽  
Mekonen Ayana
Keyword(s):  
Water Management ◽  
Focus Group ◽  
Irrigation Water ◽  
Hydraulic Performance ◽  
Small Scale ◽  
Irrigation Scheme ◽  
Focus Group Discussions ◽  
Group Discussions ◽  
Cause And Effect ◽  
Small Scale Irrigation

Performances assessment of irrigation schemes network is very essential in taking different water management strategies. However, the performance of Mychew irrigation scheme was not assessed and hence, this research was undertaken to assess the hydraulic performance of Mychew small scale irrigation scheme. Moreover, identification of the cause and effect for mal-functionality of irrigation structures was also another objective of this study. Hence, comprehensive field observations, measurements and focus group discussions were held to investigate hydraulic performance, cause and effect of failed hydraulic structures. Simple descriptive statistics was employed for analysis of the data collected from focus group discussions and observations. Eight performance indicators were used to assess the performance of this irrigation scheme. Several factors such as sedimentation, design problem, damage of sluice gates, abstraction of irrigation water by unwanted plants has been identified for mal-functionality of different structures. There were problems in irrigation adequacy (0.75) and equity (0.28) of irrigation water was categorized as poor, while good and fair for dependability (0.08) and irrigation efficiency (0.79), respectively. The average water surface elevation ratio, delivery performance ratio, and delivery duration ratio of the main canal during the monitoring period was less than one, greater than 5% and 150%, respectively. The highest sediment accumulation was observed at head and middle reaches of the irrigation scheme than the tail reaches. Generally, there were a number of irrigation structures which was mal-functioned in this irrigation scheme. Now it needs sustainable solution to improve the performance of the irrigation scheme. Therefore, it was recommended that water should be fairly distributed spatially and temporally. Additionally, capacity building and awareness creation to concerned bodies holds the key to bring a difference in irrigation water management in this irrigation scheme.

scholarly journals The FLOod Probability Interpolation Tool (FLOPIT): A Simple Tool to Improve Spatial Flood Probability Quantification and Communication

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 666
Author(s):  
Mahkameh Zarekarizi ◽  
K. Joel Roop-Eckart ◽  
Sanjib Sharma ◽  
Klaus Keller
Keyword(s):  
Flood Risk ◽  
Water Surface ◽  
The United States ◽  
Surface Elevation ◽  
Exceedance Probability ◽  
Water Surface Elevation ◽  
Inundation Maps ◽  
Probability Maps ◽  
Flood Probability ◽  
Floodplain Development

Understanding flood probabilities is essential to making sound decisions about flood-risk management. Many people rely on flood probability maps to inform decisions about purchasing flood insurance, buying or selling real-estate, flood-proofing a house, or managing floodplain development. Current flood probability maps typically use flood zones (for example the 1 in 100 or 1 in 500-year flood zones) to communicate flooding probabilities. However, this choice of communication format can miss important details and lead to biased risk assessments. Here we develop, test, and demonstrate the FLOod Probability Interpolation Tool (FLOPIT). FLOPIT interpolates flood probabilities between water surface elevation to produce continuous flood-probability maps. FLOPIT uses water surface elevation inundation maps for at least two return periods and creates Annual Exceedance Probability (AEP) as well as inundation maps for new return levels. Potential advantages of FLOPIT include being open-source, relatively easy to implement, capable of creating inundation maps from agencies other than FEMA, and applicable to locations where FEMA published flood inundation maps but not flood probability. Using publicly available data from the Federal Emergency Management Agency (FEMA) flood risk databases as well as state and national datasets, we produce continuous flood-probability maps at three example locations in the United States: Houston (TX), Muncy (PA), and Selinsgrove (PA). We find that the discrete flood zones generally communicate substantially lower flood probabilities than the continuous estimates.

scholarly journals Integrating Participatory Data Acquisition and Modelling of Irrigation Strategies to Enhance Water Productivity in a Small‐Scale Irrigation Scheme in Tigray, Ethiopia

2020 ◽  
Vol 69 (S1) ◽  
pp. 23-37
Author(s):  
Solomon Habtu ◽  
Teklu Erkossa ◽  
Jochen Froebrich ◽  
Filmon Tquabo ◽  
Degol Fissehaye ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Water Productivity ◽  
Small Scale ◽  
Irrigation Scheme ◽  
Small Scale Irrigation

Morphodynamic stability and characteristic length scales of bifurcations and confluences loops

2021 ◽  
Author(s):  
Niccolò Ragno ◽  
Marco Redolfi ◽  
Marco Tubino
Keyword(s):  
Froude Number ◽  
Water Surface ◽  
Characteristic Length ◽  
Coupled Model ◽  
Surface Elevation ◽  
Momentum Balance ◽  
Water Surface Elevation ◽  
Control Volumes ◽  
Almost All ◽  
Fluvial Environments

<p>The morphodynamics of multi-thread fluvial environments like braided and anastomosing rivers is fundamentally driven by the continuous concatenation of channel bifurcations and confluences, which govern the distribution of flow and sediment among the different branches that are reconnecting further downstream. Almost all studies performed to date consider the two processes separately, although they frequently appear as closely interconnected. In this work, we tackle the problem of analyzing the coupled morphodynamics of such bifurcation-confluence systems by studying the equilibrium and stability conditions of a channel loop, where flow splits into two secondary anabranches that rejoin after a prescribed distance. Through the formulation of a novel theoretical model for erodible bed confluences based on the momentum balance on two distinct control volumes, we show that the dominating anabranch (i.e. that carrying more water and sediment) is subject to an increase of the water surface elevation that is proportional to the square of the Froude number. This increase in water surface elevation tends to reduce the slope of the dominating branch, which produces a negative feedback that tends to stabilize the bifurcation-confluence system. A linear analysis of the coupled model reveals that the stabilizing effect of the confluence depends on the ratio between the length of the connecting channels and the average water depth, independently of the channel slope and Froude number. Furthermore, the effect of the confluence is potentially able to stabilize the channel loop in conditions where the classic stabilizing mechanism at the bifurcation (i.e. the topographical effect related to the gravitational pull on the sediment transport) is very weak, as expected when most of the sediment is transported in suspension. The identification of a characteristic length scale that produces a coupling between the confluences and bifurcations opens intriguing possibilities for interpreting the self-adjustment of the planform scale of natural multi-thread rivers.</p>

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