Failure of the Mtera-Kidatu reservoir system in the Early 1990s

Four possible causes for the failure of the Mtera-Kidatu Reservoir System within the Rufiji River Basin in Tanzania in the early 1990s were investigated. These were sudden decrease in inflows, sudden increase in losses, sudden increase in hydropower generation, and unnecessary spills; or a combination of these, and it was found out that unaccounted for and unnecessary spillage was the main cause. This paper proposes that consideration of the flows that are generated within the intervening catchment (i.e. catchment between Mtera and Kidatu) and the operational policy that maximum power is produced at Kidatu most of the time must be the core in the management of the reservoir system. If this was the case in the past then the Mtera Reservoir should not have gone dry in the 1991-1994 period. The validity of this assertion was tested with the TALSIM 2.0 model and an efficiency of 95% was achieved, indicating a very good correlation with the investigative techniques employed in this study

Modelling the Mtera-Kidatu reservoir system to improve integrated water resources management

Failure of the Mtera-Kidatu Reservoir System within the Rufiji River Basin in Tanzania in the early 1990s is investigated by considering four possible causes (i.e. sudden decrease in inflows, sudden increase in losses, sudden increase in hydropower generation or unnecessary spills; or a combination of these) and it was found out that unaccounted spillage seems to be the main cause. Consequently, the system’s simulation model has been proposed in this paper that takes into consideration the flows that are generated in the intervening catchment (i.e. catchment between Mtera and Kidatu) with the operational policy that maximum power is produced at Kidatu most of the time because Kidatu has higher head for greater power generation than at Mtera. The paper shows that if this proposed model had been in place then the Mtera Reservoir should not have gone dry in the 1991-1994 period. The validity of the proposed model is tested with the TALSIM 2.0 Model and the regression analysis of the water levels at Mtera Reservoir produced by the models had an efficiency of 95%, indicating a very good correlation. The proposed model operates the reservoir system in an integrated manner by considering the flows into the Mtera Reservoir as well as accounting for the flows generated by the intervening catchment

Modulation of GmFAD3 expression alters responses to abiotic stress in soybean

FAD3 play important roles in modulating membrane fluidity in response to various abiotic stresses. However, a comprehensive analysis of FAD3 in drought, salinity and heat stress tolerance is lacking in soybean. The present study assessed the functional role of fatty acid desaturase 3 to abiotic stress responses in soybean. We used Bean Pod Mottle Virus -based vector to alter expression of Glycine max omega-3 fatty acid desaturase . Higher levels of recombinant BPMV-GmFAD3 transcripts were detected in overexpressing soybean plants. Overexpression of GmFAD3 in soybean resulted in increased levels of jasmonic acid and higher expression of GmWRKY54 as compared to mock-inoculated, vector-infected and FAD3-silenced soybean plants under drought and salinity stress conditions. FAD3 overexpressing plants showed higher levels of chlorophyll content, leaf SPAD value, relative water content, chlorophyll fluorescence, transpiration rate, carbon assimilation rate, proline content and also cooler canopy under drought and salinity stress conditions as compared to mock-inoculated, vector-infected and FAD3-silenced soybean plants. Results from current study revealed that GmFAD3 overexpressing soybean plants exhibited drought and salinity stress tolerance although tolerance to heat stress was reduced. On the other hand, soybean plants silenced for GmFAD3 exhibited tolerance to heat stress, but were vulnerable to drought and salinity stres

A non-linear perturbation model considering catchment wetness and its application in river flow forecasting

A non-linear perturbation model for river flow forecasting is developed, based on consideration of catchment wetness using an antecedent precipitation index (API). Catchment seasonality, of the form accounted for in the linear perturbation model (the LPM), and non-linear behaviour both in the runoff generation mechanism and in the flow routing processes are represented by a constrained nan-linear model, the NLPM-API. A total of ten catchments, across a range of climatic conditions and catchment area magnitudes, located in China and in other countries, were selected for testing daily rainfall-runoff forecasting with this model. It was found that the NLPM-API model was significantly more efficient than the original linear perturbation model (the LPM). However, restric tion of explicit nan-linearity to the runoff generation process, in the simpler LPM-API form of the model, did not produce a significantly lower value of the efficiency in flood forecasting, in terms of the model efficiency index R-2. (C) 1997 Elsevier Science B.V

The relationship between basal and induced resistance in Arabidopsis

Plants are constantly exposed to potentially pathogenic micro-organisms. They possess an extensive array of passive and active defense mechanisms, and only a small proportion of micro-organisms are capable of infecting the plant and causing disease. Plant resistance can be broadly defined as the plant's ability to suppress or retard the damaging activity of a pathogen. The most common type of resistance is nonhost resistance. This type of resistance protects the plant entirely from infection by most potential pathogens, and is manifested as an inability of the pathogen to cause disease upon contact with any individual of a particular plant species. In such an interaction, the pathogen is nonpathogenic