Mitigation of flash floods in arid regions using adjoint sensitivity analysis

This paper presents an analysis of the sensitivities of flood wave propagation to variations in certain control variables and boundary conditions by means of the adjoint method. This uses a variational technique to find the relationships between changes in predicted flood water levels and changes in control variables such as the inflow hydrograph, bed roughness, and bed elevation. The sensitivities can be used for optimal control of hydraulic structures, for data assimilation, for decision makers' procedures, for the analysis of the effects of uncertainties in control variables on the predictions of floods water levels, and for investigating both the sensitivities of model flood forecasts to model parameters, boundary and initial conditions. Example of the last application of the sensitivity analysis is presented and discussed These methods are developed and implemented through a numerical hydraulic model of channel flow based on the Shallow Water Equations (SWEs) and the corresponding adjoint model. The equations are integrated using finite difference methods and a new modified method of characteristics is used to define the open boundaries. Results of validation tests on both the forward hydraulic model and on the adjoint model are presented

Modelling uncertainty for flash floods in coastal plains using adjoint methods

This paper shows the application of adjoint sensitivity analysis to flash flood wave propagation in a river channel. The adjoint sensitivity analysis is used to assess flood hazard in a coastal area caused by river discharge. The numerical model determines the sensitivities of predicted water levels to uncertainties in key controls such as inflow hydrograph, channel topography, frictional resistance and infiltration rate. Sensitivities are calculated using the adjoint equations and are specified in terms of water levels being greater than certain safe threshold levels along the channel. The flood propagation model is based on the St. Venant equations while the propagation of sensitivity information is based on the corresponding adjoint equations. This analysis is achieved using a numerical model that integrates The St. Venant equations forward in time using a staggered finite difference scheme. An enhanced method of characteristics at the downstream boundary provides open boundary conditions and overcomes the problem of reflections from the boundaries. Then, the adjoint model is integrated backwards in time to trace the sensitivity information back through the model domain towards the inflow control boundary. The adjoint model has been verified by means of an identical twin experiment

The effect of water stage on the infiltration rate for initially dry channels

Several hydrological models that are used for simulating the water flow in rivers and channels are based on the shallow water equations as in Copeland and El-Hanafy, (2006) or Saint Venant equations (El-Hanafy and Copeland, 2007a). Both the shallow water equations and the Saint Venant equations form a system of partial differential equations which presents mass and momentum conservation along the channel and include source terms for the bed slope and bed friction. This paper presents a staggered finite difference scheme for the channel routing based upon Saint Venant equations and the well know method of characteristics after modifying it to suit the case of a shallow water depth initially followed by a flood event (El-Hanafy and Copeland, 2007b). The modified method of characteristics is implemented to achieve a transparent down stream boundary. The relation between the water depth and the infiltration rate have been derived for Saint Venant equations and it is concluded that the effect of water stage have a positive effect on the infiltration rate as it was expected

Computer modelling of channel flow using an inverse method

We may not be able to command the water to stop but we can take steps to predict when and where it will invade and attack our lives, and provide solutions to deal with the problem. The research project reported in this paper is concerned with a study of unsteady free surface water flow, a hydrograph, resulting from a watershed just after the outlet station. The quality of flood predictions by numerical models depends on the accuracy of the inflow hydrograph, other control variables such as bed roughness, infiltration rate, and channel topography. However, none of these are well known, the values of each are uncertain. This research examines what effect these uncertainties have on the flood prediction. That is we find out how the uncertainties in control values propagate through the model. This is achieved by calculating the sensitivities of the flood predictions to changes (uncertainties) in control variables. The adjoint method is used to study the sensitivity of the flow to changes in the boundary and initial conditions. To achieve this aim we constructed a numerical hydraulic model to simulate the flow of water in the main stream based on the shallow water equation (SWE). The sensitivities are determined using the adjoint method which uses a variational technique to find the relationships between changes in channel flow conditions and changes in control variables such as the inflow hydrograph. This could be done at significant computational expense using multiple runs and ensemble techniques however the adjoint method presented here determines these sensitivities analytically in one run of the model

Flash floods simulation using Saint Venant equations

Flash floods prediction is considered one of the important environmental issues worldwide. In order to predict when and where the flood wave will invade and attack our lives, and provide solutions to deal with this problem it is essential to develop a reliable model that simulates accurately this physical phenomena. The research project reported in this paper is concerned with a study of unsteady free surface water flow, a hydrograph, resulting from a watershed just after the outlet station. To achieve this aim a numerical hydraulic model has been constructed to simulate the flow of water in the main stream based on the Saint Venant equations (SVES) using a staggered finite difference scheme to evaluate the discharge, the water stage, and the cross section area within the domain. While the Method Of Characteristics (MOC) is applied to achieve open boundary downstream and overcome the problem of reflections there. The developed model had passed a series of tests which indicated that this model is capable of simulating different cases of water flow that contain both steady and unsteady flow. Once the flood had been predicted it could be used as a stepping stone for different purposes including parameter identification (Ding et al. 2004), evaluating the sensitivity of the flood to some control variables (Copeland and Elhanafy 2006), Flood risk assessment (Elhanafy and Copeland 2007) ,uncertainty in the predicted flood (Elhanafy and Copeland 2007) and (Elhanafy et al. 2007)

The Role of Environmental Payments in Sustaining Farm Incomes: A Four Year Study of Farm Businesses in an Upland Area of the UK

A representative sample of both participant and non-participant case study farms was examined over a three-year period in the Shropshire Hills Environmentally Sensitive Area of the UK from 1997 to 2000. The effects on farm business viability were monitored and results compared with two relevant sub samples of Farm Business Survey recorded farms. The study showed that farming profitability declined sharply over the study period but that participant case study farm profitability exceeded that of non-participants by an average of £4024 per year. This was attributable to a combination of factors which included larger average farm size, the ESA premium and more intensive farming operations. Subsidies received by both types of farms were almost totally on the "per head" basis and averaged £270 per hectare. Without these both classes of farms would have been highly unprofitable. The status of the ESA premium compared with these figures was an average of 4.5 percent of business turnover or £2358 per farm, well below that of headage based subsidies. Return on capital invested in land was consistently low, suggesting that even with these levels of subsidies the long-term future of these farms could be uncertain. The results achieved were consistent with those obtained from the Farm Business Survey data provided for the two relevant sub-samples.Farm Management,

"Citizenship Matters": Lessons from the Irish Citizenship Referendum

In 2004, by constitutional referendum, Ireland revoked the automatic right to citizenship by territorial birth (jus soli). This event is of great significance in Europe, where consequently there is no longer a single nation that grants unrestricted territorial birthright citizenship to people born within its borders, and also represents a trend toward the revocation of jus soli within nations governed by the common law tradition. But the Irish Citizenship Referendum also invites comparative analysis with the United States, where jus soli is protected by the Fourteenth Amendment, due both to the historical and contemporary links between the two nations and the presence of contemporary pressures to undermine jus soli in the United States that are similar to those that resulted in the Irish Citizenship Referendum. In this article, we discuss both the importance of U.S. practice for the normative discussions surrounding the removal of jus soli as an automatic qualification for citizenship in Ireland, and the importance of the Irish debates as an example for the historical and normative investigation of the foundations of citizenship in the United States, especially in the field of American studies. In particular, we propose that the Irish Citizenship Referendum illuminates the need to reconsider the relationship between restrictionism in immigration and in citizenship, often cast in American Studies as a direct relationship. The Irish case shows that a successful campaign for limits on access to citizenship was made in the absence of policies limiting immigration. One of the purposes and effects of citizenship restriction in a context of increased immigration, we propose, is the creation of a dual and unequal workforce. For this reason, we argue that the elimination of jus soli as a basis for citizenship was unjustified in the Irish case, despite the popular pressures on Irish politicians, and that the pressure being placed on U.S. politicians to undermine jus soli should be consciously resisted

"Citizenship Matters": Lessons from the Irish Citizenship Referendum

In 2004, by constitutional referendum, Ireland revoked the automatic right to citizenship by territorial birth (jus soli). This event is of great significance in Europe, where consequently there is no longer a single nation that grants unrestricted territorial birthright citizenship to people born within its borders, and also represents a trend toward the revocation of jus soli within nations governed by the common law tradition. But the Irish Citizenship Referendum also invites comparative analysis with the United States, where jus soli is protected by the Fourteenth Amendment, due both to the historical and contemporary links between the two nations and the presence of contemporary pressures to undermine jus soli in the United States that are similar to those that resulted in the Irish Citizenship Referendum. In this article, we discuss both the importance of U.S. practice for the normative discussions surrounding the removal of jus soli as an automatic qualification for citizenship in Ireland, and the importance of the Irish debates as an example for the historical and normative investigation of the foundations of citizenship in the United States, especially in the field of American studies. In particular, we propose that the Irish Citizenship Referendum illuminates the need to reconsider the relationship between restrictionism in immigration and in citizenship, often cast in American Studies as a direct relationship. The Irish case shows that a successful campaign for limits on access to citizenship was made in the absence of policies limiting immigration. One of the purposes and effects of citizenship restriction in a context of increased immigration, we propose, is the creation of a dual and unequal workforce. For this reason, we argue that the elimination of jus soli as a basis for citizenship was unjustified in the Irish case, despite the popular pressures on Irish politicians, and that the pressure being placed on U.S. politicians to undermine jus soli should be consciously resisted

Automated design analysis, assembly planning and motion study analysis using immersive virtual reality

Previous research work at Heriot-Watt University using immersive virtual reality (VR) for cable harness design showed that VR provided substantial productivity gains over traditional computer-aided design (CAD) systems. This follow-on work was aimed at understanding the degree to which aspects of this technology were contributed to these benefits and to determine if engineering design and planning processes could be analysed in detail by nonintrusively monitoring and logging engineering tasks. This involved using a CAD-equivalent VR system for cable harness routing design, harness assembly and installation planning that can be functionally evaluated using a set of creative design-tasks to measure the system and users' performance. A novel design task categorisation scheme was created and formalised which broke down the cable harness design process and associated activities. The system was also used to demonstrate the automatic generation of usable bulkhead connector, cable harness assembly and cable harness installation plans from non-intrusive user logging. Finally, the data generated from the user-logging allowed the automated activity categorisation of the user actions, automated generation of process flow diagrams and chronocyclegraphs

Microarray analyses demonstrate the involvement of type i interferons in psoriasiform pathology development in D6-deficient mice

The inflammatory response is normally limited by mechanisms regulating its resolution. In the absence of resolution, inflammatory pathologies can emerge, resulting in substantial morbidity and mortality. We have been studying the D6 chemokine scavenging receptor, which played an indispensable role in the resolution phase of inflammatory responses and does so by facilitating removal of inflammatory CC chemokines. In D6-deficient mice, otherwise innocuous cutaneous inflammatory stimuli induce a grossly exaggerated inflammatory response that bears many similarities to human psoriasis. In the present study, we have used transcriptomic approaches to define the molecular make up of this response. The data presented highlight potential roles for a number of cytokines in initiating and maintaining the psoriasis-like pathology. Most compellingly, we provide data indicating a key role for the type I interferon pathway in the emergence of this pathology. Neutralizing antibodies to type I interferons are able to ameliorate the psoriasis-like pathology, confirming a role in its development. Comparison of transcriptional data generated from this mouse model with equivalent data obtained from human psoriasis further demonstrates the strong similarities between the experimental and clinical systems. As such, the transcriptional data obtained in this preclinical model provide insights into the cytokine network active in exaggerated inflammatory responses and offer an excellent tool to evaluate the efficacy of compounds designed to therapeutically interfere with inflammatory processes