Hydraulic Performance Evaluation of Community-Managed Irrigation Scheme, North Shewa, Amhara, Ethiopia

Background: Irrigation scheme performance assessment is vital to evaluate the impacts of irrigation practices, to identify performance gaps and to improve system performances. However, irrigation performance assessment has not been carried out for Yelen irrigation scheme since its operation. Therefore, this study has been done with the purpose of identifying and understanding the current level of irrigation performance of Yelen irrigation scheme. The indicators of adequacy, efficiency, dependability, deficiency and equity were used to determine hydraulic performance. Primary data were collected through flow measurement using current meter and Parshall flume, transect walk, household surveys and group discussions, whereas Secondary data were collected from different sources. CROPWAT 8.0 model, SPSS, Microsoft excels and GIS software was used to analyze the data. Water delivery indicators were evaluated from the amounts of water which was actually applied and which should have been applied.Results: According to the results of the study, the value of adequacy, dependability, efficiency, deficiency and equity were found to be 0.84, 0.26, 0.93, 0.17and 0.34 respectively. Generally, the performance of the irrigation system is poor. It mainly resulted due to water scarcity, illegal water abstraction, sedimentation of canals and inadequate operation and maintenance provisions.Concussions: Therefore, adequate maintenance and suitable management approaches are required to improve the irrigation system performance. Under the water scarce situations, improving the performance of water delivery systems can offer an opportunity to realize field level water savings.

Rehabilitation of operation regimes in aged irrigation schemes based on hydraulic simulation

The selection and employment of proper methods in water distribution causes increasing in water productivity and the level of satisfaction of water users. It is faced with more difficulties in aged irrigation projects due to temporal changes such as changes in the crop patterns, development of the command area and destruction of canals and hydraulic structures. The plan of operation methods have some hydraulic and social complexities and therefore is usually simplified or implemented experimentally. This research investigates the best options for water distribution to the paddy fields in a subunit of Sefidroud irrigation scheme based on field survey, recording real data and hydraulic simulation with employing SOBEK hydrodynamic model. Different operation scenarios were defined and then simulated in the current physical state of the scheme through replacing the exhausted intake structures with sluice gates. Finally, the better operation scenarios during the irrigation season were suggested based on the distribution indices. The results show that in spite of the current situation, water loss could reach the minimum by employing modification scenarios and indices of adequacy and equity of water distribution improve.

Unpacking Negative Externalities of Social Capital in the Sustainability of Smallholder Rural Irrigation Farming: The Case of Rozva Irrigation Scheme in Bikita District, Zimbabwe

The article examines the negative externalities of social capital in the sustainability of smallholder irrigation farming. Smallholder irrigation farming has become one of the main sources of rural livelihood in Zimbabwe given the deficiencies in rainfall triggered by climate change among other factors. The establishment of smallholder irrigation schemes, refurbishment of irrigation infrastructure, introduction of new technology and the subsidization of farm inputs are several initiatives taken by the government of Zimbabwe, Non-Governmental organisations and the private sector to improving agricultural productivity among smallholder irrigation schemes. Despite these efforts, smallholder irrigation farming has remained unsustainable. Resultantly, most rural communities in Zimbabwe continue to face hunger and poverty, two overarching sustainable development goals (SDGs 1 & 2) one and two. This study examined the negative externalities of social capital on efforts to improve productivity and sustainability of Rozva smallholder irrigation scheme. The article argues that linking social capital, which includes partnerships between Rozva irrigation farmers and donor agencies, has created dependency syndrome that is inimical to the sustainability of the irrigation scheme. The article concludes some social connections detrimental to the sustainability of the scheme tend to create divisions among farmers. The article argues there is need for awareness on negative externalities of social capital and reduce these effects on the sustainability of the smallholder irrigation to realise social capital benefits among irrigation farming communities in Zimbabwe.

A Deterministic Analysis of the Effectiveness of Non-Clinical Approaches in the Control of Transimission of Schistosomiasis: Case Study of Mwea Irrigation Scheme, Kenya

Schistosomiasis commonly known as bilharzia is regarded by W.H.O as a neglected tropical disease. It affects the intestines and the urinary system preferentially, but can harm other systems in the body. The disease is a health concern among majority of the population in Mwea irrigation scheme in Kenya and indeed other tropical countries. This paper documents a deterministic analysis of the effectiveness of non-clinical approaches in the control of transmission of schistosomiasis in the region. A SIR based mathematical model that incorporates media campaigns as a control strategy of reducing transmission of the disease is used. The model considers behavior patterns of hosts as the main process of transmission of the disease. The dynamics of these processes is expressed in terms of ordinary differential equations deduced from the human behavior patterns that contribute to the spread of the disease. The reproduction number R0 and equilibrium points both DFE and EE are obtained. The stabilities of these equilibrium points are analyzed in reference to the reproduction number (R0). Secondary data is used in the mathematical model developed and in the prediction of the dynamics estimated in the model for a period of five years. Numerical simulation was carried out and results represented graphically. The results of the simulation show that the infection decreased from 75108 to about 35000 and the susceptible from 325142 to 50000 respectively in a period of five years. From the analysis, the DFE point is asymptotically stable when R_0<1.Sensitivity analysis of parameters was carried out using partial differentiation. The results show that the sensitivity index of most parameters are inversely proportional to R0 which will reduce schistosomiasis infection. From the results, incorporation of media campaigns as a control strategy significantly reduces transmission of the disease. The results will be useful to MOH to enhance media campaigns to prevent spread of schistosomiasis in Mwea Irrigation scheme and other endemic areas.

Statistical Model for Predicting Salinity of Water at Doho 1 Irrigation Scheme in Busia.

The concentration of salts in water or salt affects crop yields to a good extent. Irrigation salinity can be controlled by various methods including modelling. Therefore, this study aimed at designing a model for predicting the salinity of the water at the Doho Irrigation Scheme in Butaleja district, eastern Uganda for better rice growing. This study used the different water chemical parameters from the different sites of the scheme, where water samples were collected and measured in the laboratory. A multivariate regression method was used to model water salinity through the Electrical Conductivity as the dependent variable and other water chemical parameters like potassium (K), Sodium (Na), pH and Calcium (Ca) were used as independent variables. A non-linear statistical model was derived from the chemical results of the irrigation scheme, presented and validated by applying it on the water samples that were not used during the design of the model. The model measured salinity levels and can be used to determine which water chemical levels are good for rice growing in Doho and other similar situations. Hence, the model can be used to improve food quality and quantity as required in the food production goal

Optimizing a backscatter forward operator using Sentinel-1 data over irrigated land

Worldwide, the amount of water used for agricultural purposes is rising, and the quantification of irrigation is becoming a crucial topic. Because of the limited availability of in situ observations, an increasing number of studies is focusing on the synergistic use of models and satellite data to detect and quantify irrigation. The parameterization of irrigation in large-scale land surface models (LSMs) is improving, but it is still hampered by the lack of information about dynamic crop rotations, or the extent of irrigated areas, and the mostly unknown timing and amount of irrigation. On the other hand, remote sensing observations offer an opportunity to fill this gap as they are directly affected by, and hence potentially able to detect, irrigation. Therefore, combining LSMs and satellite information through data assimilation can offer the optimal way to quantify the water used for irrigation. This work represents the first and necessary step towards building a reliable LSM data assimilation system which, in future analysis, will investigate the potential of high-resolution radar backscatter observations from Sentinel-1 to improve irrigation quantification. Specifically, the aim of this study is to couple the Noah-MP LSM running within the NASA Land Information System (LIS), with a backscatter observation operator for simulating unbiased backscatter predictions over irrigated lands. In this context, we first tested how well modelled surface soil moisture (SSM) and vegetation estimates, with or without irrigation simulation, are able to capture the signal of aggregated 1 km Sentinel-1 backscatter observations over the Po Valley, an important agricultural area in northern Italy. Next, Sentinel-1 backscatter observations, together with simulated SSM and leaf area index (LAI), were used to optimize a Water Cloud Model (WCM), which will represent the observation operator in future data assimilation experiments. The WCM was calibrated with and without an irrigation scheme in Noah-MP and considering two different cost functions. Results demonstrate that using an irrigation scheme provides a better calibration of the WCM, even if the simulated irrigation estimates are inaccurate. The Bayesian optimization is shown to result in the best unbiased calibrated system, with minimal chances of having error cross-correlations between the model and observations. Our time series analysis further confirms that Sentinel-1 is able to track the impact of human activities on the water cycle, highlighting its potential to improve irrigation, soil moisture, and vegetation estimates via future data assimilation.