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The Africa Infrastructure Country Diagnostic (AICD) has produced continent-wide analysis of many aspects of Africa's infrastructure challenge. The main findings were synthesized in a flagship report titled Africa's Infrastructure: a time for transformation, published in November 2009. Meant for policy makers, that report necessarily focused on the high-level conclusions. It attracted widespread media coverage feeding directly into discussions at the 2009 African Union Commission Heads of State Summit on Infrastructure. Although the flagship report served a valuable role in highlighting the main findings of the project, it could not do full justice to the richness of the data collected and technical analysis undertaken. There was clearly a need to make this more detailed material available to a wider audience of infrastructure practitioners. Hence the idea of producing four technical monographs, such as this one, to provide detailed results on each of the major infrastructure sectors, information and communication technologies (ICT), power, transport, and water, as companions to the flagship report. These technical volumes are intended as reference books on each of the infrastructure sectors. They cover all aspects of the AICD project relevant to each sector, including sector performance, gaps in financing and efficiency, and estimates of the need for additional spending on investment, operations, and maintenance. Each volume also comes with a detailed data appendix, providing easy access to all the relevant infrastructure indicators at the country level, which is a resource in and of itself.

Long-term droughts observed in southern Australia have changed relationships between annual rainfall and runoff and tested some of the assumptions implicit in rainfall–runoff models used in these areas. Predictive confidence across these periods is when low using the more commonly used rainfall–runoff models. Here we modified the GR4J model to better represent surface water–groundwater connection and its role in runoff generation. The modified model (GR7J) was tested in 137 catchments in south-east Australia. Models were calibrated during “wetter” periods and simulation across drought periods was assessed against observations. GR7J performed better than GR4J in evaluation during drought periods where bias was significantly lower and showed improved fit across the flow duration curve especially at low flows. The largest improvements in predictive performance were for catchments where there were larger changes in the annual rainfall–runoff relationship. The predictive performance of the GR7J model was more sensitive to objective function used than GR4J. The use of an objective function that combined daily and annual error produced a better goodness of fit when measured against 80, 50 and 20 percent excedance flow quantiles and reduced evaluation bias, especially for the GR7J model.

Ecosystems are increasingly managed to provide multiple benefits to humans, which often degrades their ecological integrity. This strongly applies to aquatic ecosystems, in which engineering can enhance flood protection, drinking water supply, fisheries and recreation. Although these activities typically increase ecosystem functionality to humans, they often impair key aspects of biodiversity and natural functioning. Classical restoration of such degrading freshwater ecosystems can lead to societal opposition, if returning to a former ecosystem state affects previously acquired ecosystem services. Innovative nature‐based solutions are therefore needed that enhance natural values in ecosystems, without affecting existing services. We present a large‐scale project aiming to increase the ecological integrity of a human‐modified freshwater lake while maintaining its services to humans. The freshwater lake Markermeer in the Netherlands was formed by closing off an estuary for flood protection. The ecological integrity of this lake diminished over time, likely because a declining primary productivity impaired biodiversity at higher trophic levels. This decline is associated with a lack of gradual land–water transitions, strong resuspension of fine sediments, low nutrient availability and lack of dynamics typically to be expected in a natural temperate freshwater lake. Restoring the lake to its former marine state would conflict with current ecosystem services. A nature‐based solution was initiated in 2016, consisting of constructing a five‐island archipelago from the lake's own soft‐sediments called the ‘Marker Wadden’. The project aims to increase the lake's primary production by creating gradual land–water transitions, more heterogeneity in water depths and decreasing turbidity by creating shelter and deep sinks reducing fine‐sediment resuspension by the wind – thus introducing currently missing elements that are typical for natural lakes. We present the underlying ecological framework and first scientific results of this innovative ongoing project. Within 4 years, the Marker Wadden project shows how forward‐looking sustainable development of lake ecosystems using a rewilding approach can enhance natural processes and attract birds and fish, without conflicting with existing ecosystem services. This inspires new directions for halting and reversing the degradation of other vital ecosystems worldwide. Samenvatting Economische ontwikkelingen gaan vaak ten koste van de ecologische integriteit van ecosystemen. Dit geldt zeker voor zoetwater‐ecosystemen die worden ingericht ten behoeve van de waterveiligheid, drinkwatervoorziening, commerciële bevissing of recreatie. Maar wat voor mensen mogelijk een verbetering van de functionaliteit van een rivier of meer betekent, gaat vaak ten koste van de biodiversiteit en ruimte voor natuurlijke processen. Herstel van beschadigde zoetwater‐ecosystemen op klassieke wijze, namelijk het terugkeren naar de situatie van voor het menselijk ingrijpen, kan maatschappelijke weerstand oproepen als dit ten koste gaat van die eerder verworven ecosysteem diensten. Het vergt innovatieve oplossingen gericht op natuurlijke processen om de natuurwaarden te verhogen en tegelijkertijd de functionaliteit voor de mens ervan te behouden. Deze nieuwe vorm van ecosysteemherstel is toegepast in een grootschalig project in het Nederlandse Markermeer. Het Markermeer is in 1975 kunstmatig ontstaan in het voormalig estuarium van De Zuiderzee door bedijking voor de waterveiligheid. De afgelopen decennia is de ecologische waarde van het Markermeer steeds verder achteruitgegaan, waarschijnlijk doordat de primaire productie afneemt, met consequenties voor het hele voedsel web. Deze afname van productiviteit wordt geassocieerd met een gebrek aan natuurlijke land‐water overgangen, slecht doorzicht door continue opwerveling van grote hoeveelheden fijn slib, lage beschikbaarheid van voedingsstoffen en een gebrek aan natuurlijke dynamiek die past bij een natuurlijk gevormd ondiep zoetwatermeer. Klassiek herstel van de ecologische integriteit van het Markermeer via terugkeer naar de voormalige Zuiderzee is inmiddels onmogelijk omdat dit in strijd is met de huidige ecosysteemfuncties. In 2016 is daarom begonnen met een innovatieve vorm van ecosysteemherstel: de bouw van een nieuwe archipel van vijf eilanden, de Marker Wadden. De eilanden hebben als doel de primaire productie van het Markermeer te stimuleren door het toevoegen van karakteristieke elementen van natuurlijke meren die op dit moment in het meer ontbreken. Dit zijn met name geleidelijke land‐waterovergangen, variatie in waterdieptes en luwten tussen de eilanden waar het door de wind opwervelende slib kan bezinken. Hier presenteren we de ecologische achtergrond en eerste wetenschappelijke bevindingen van dit unieke en innovatieve project. Binnen vier jaar laat het Marker Wadden‐project zien hoe natuurontwikkeling volgens een rewilding benadering een stimulans kan geven aan natuurlijke processen. Vogels en vissen blijken het nieuwe gebied direct in gebruik te nemen, terwijl de ecosysteemfuncties voor de mens behouden zijn gebleven. Dit project kan dienen als voorbeeld van een nieuwe vorm van ecosysteemherstel, wat hard nodig is om de huidige achteruitgang van belangrijke ecosystemen wereldwijd ten goede te keren. The Marker Wadden project shows how forward‐looking sustainable development of lake ecosystems using a rewilding approach can enhance natural processes and attract birds and fish, without conflicting with existing ecosystem services. This inspires new directions for halting and reversing the degradation of other vital ecosystems worldwide.

More than 1 billion people around the world live without access to safe, potable water, in part because of poor governance and corruption. Illegal connections and substantial losses caused by deferred maintenance have eroded the revenues of water utilities, leading to a downward spiral in performance. Embezzlement of funds, bribes for access to illegal water connections, manipulation of meter counters, and collusion in public contracts add to the litany of corrupt practices. 'Improving Transparency, Integrity, and Accountability in Water Supply and Sanitation' is a useful tool for diagnosing, analyzing, and remedying systemic corruption in the water supply and sanitation sectors. It will serve as a practical guide for governments; utility regulators, managers, and staff; civil society organizations; contractors; and citizens in their quest for a model of service provision that responds to the pressing needs of people in the developing world. The book aims to increase the involvement of civil society by engaging all stakeholders in setting priorities and monitoring performance; help water and sanitation delivery contribute to poverty reduction by increasing the service quality and coverage provided by service delivery organizations to poorer communities on an equitable basis; provide a tool that promotes the financial sustainability of service delivery organizations, thus building stakeholders' confidence in those institutions' ability to expand and improve service; and raise ethical standards among all stakeholders, especially service delivery organizations, thereby instilling a sense of public service in these organizations.

This study explores whether piped water connection improves people’s happiness. To answer this question, the survey on rural households’ piped water connection situation along with happiness questions was conducted in the rural areas of Cambodia, China, and the Philippines. In these countries, it is common to find areas where some households have access to piped water system while similar households in the same vicinity do not. This allows us to directly test the impact of piped water connection on happiness. The findings of this study firmly suggest that piped water generally increase happiness mainly through convenience and time saving. These benefits are more pronounced in areas with no close substitutes for the connection. Using instrumental ordered probit model to account for endogeneity of the household income variable in the happiness equation, this study estimates the value of piped water connection to be about 30% of annual household income. This study also found that recent experiences, especially bad one, would influence reported global happiness. This finding is consistent with many studies in behavioral economics, which found that people give more attention to changes occurring in loss domain than those occurring in domain of gain. Variables that capture impacts of recent experiences would therefore be necessary in the happiness equation to avoid omitted variables bias.

For the availability of drinking water, saline water treatment has become exceedingly necessary. The purpose of this research was to determine how efficient electrocoagulation (EC) with monopolar iron electrodes was for desalinating water from Iraq’s Sawa Lake. Absolute dissolved solids (TDS), chloride (Cl), bromine (Br), and sulfate (SO4) are some of the salty water forms that are being targeted. The impacts of five considerations on treatment efficiency were studied, including current (I), detention time (RT), pH, speed of mixing stirring (Mrpm), and inter-electrode distance (IED). I=0.8A, RT=80 minutes, pH=8, IED=1cm, and Mrpm=500 were found to be the best values. TDS, Cl, Br and SO4 removal efficiencies were 91 percent, 93 percent, 92 percent, and 90 percent, respectively, under ideal conditions. It can be inferred that the EC system used in this research was operative in removing salts from the water of Sawa lake.

This World Bank Study provides a basic diagnostic of access to safe water and sanitation in Uganda and their relationship with poverty. The analysis relies on a series of nationally representative household surveys for the period 2002–13, as well as on qualitative data collection. The study first relies on household surveys to analyze trends in access to safe water and some of the constraints faced by households for access. The issue of the cost of water for households without a connection to the piped water network is discussed. This includes a discussion of public stand pipes. Next, qualitative data are presented on the obstacles faced by households in accessing safe water. The next two chapters are devoted to sanitation. The focus is again first on analyzing household survey data about sanitation, including with respect to toilets, bathrooms, waste disposal, and hand washing, and next on an analysis of qualitative data from focus groups and key informants. Finally, the study reviews some of the policies and programs that have been implemented in order to improve access to safe water and sanitation for the poor as well as options going forward.

It is difficult to detect bridges in synthetic aperture radar (SAR) images due to the inherent speckle noise of SAR images, the interference generated by strong coastal scatterers, and the diversity of bridge and coastal terrain morphologies. In this paper, we present a two-step bridge detection method for polarimetric SAR imagery, in which the probability graph model of a Markov tree is used to build the water network, and bridges are detected by traversing the graph of the water network to determine all adjacent water branch pairs. In the step of the water network construction, candidate water branches are first extracted by using a region-based level set segmentation method. The water network is then built globally as a tree by connecting the extracted water branches based on the probabilistic graph model of a Markov tree, in which a node denotes a single branch and an edge denotes the connection of two adjacent branches. In the step of the bridge detection, all adjacent water branch pairs related to bridges are searched by traversing the constructed tree. Each bridge is finally detected by merging the two contours of the corresponding branch pair. Three polarimetric SAR data acquired by RADARSAT-2 covering Singapore and Lingshui, China, and by TerraSAR-X covering Singapore, are used for testing. The experimental results show that the detection rate, the false alarm rate, and the intersection over union (IoU) between the recognized bridge body and the ground truth are all improved by using the proposed method, compared to the method that constructs a water network based on water branches merging by contour distance.

This World Bank Study provides a basic diagnostic of residential piped water coverage and affordability in Uganda and its relationship with poverty using a series of nationally representative household surveys for the period 2002–13. The study fi rst analyzes trends in piped water coverage using both administrative and survey data. Demand-side and supply-side factors reducing the take-up of piped water service by households in areas where the service is available are estimated. The study also documents the extent to which piped water coverage enables households to shift time use away from domestic tasks toward market work, and the benefi cial effect that this may have on poverty. The targeting performance to the poor of water subsidies is estimated and results obtained for Uganda are compared with estimates for other countries. Finally, the study analyzes issues related to affordability—including the impact of the tariff increase of 2012 on household consumption, poverty, and piped water affordability—as well as the cost for households to connect to the piped water network.

Due to the high flow velocity and easy cavitation of high-head drainage tunnels, it is usually necessary to set up aeration facilities. In particular, when the bottom slope of the tunnel is mild, the aeration facilities often have problems such as difficulty with air intake, short cavity, and serious water accumulation, which aggravate the risk of cavitation damage. In this paper, based on the Rumei hydropower station and the Gushui hydropower station, a method combining theoretical analysis and model testing is used to solve the connection problem between the aeration facility and the 3% mild bottom slope of a tunnel body, and the aeration facility shape of “lifting ridge + flat (mild) slope + steep slope” is put forward. The research shows that the steep slope section can smoothly connect the water flow over the cantilever, reduce the jet impact angle, prevent the water from backtracking, and produce a long and stable cavity in the flat (mild) slope section. The aeration concentration along the bottom of the tunnel is higher than 3% at 140 m over the top of the dam. The aeration effect of this type is better, and it can provide effective long-distance protection for a drainage tunnel with high head and a mild bottom slope.