Irrigation ecology of schistosomiasis : environmental control options in Morocco

The concept of irrigation ecology is introduced to study the transmission and the control of urinary schistosomiasis in Moroccan irrigation systems. By distinguishing a biological, a human and an irrigation environment, crucial interactions are identified in the overlap of these three environments. In the semi-arid Haouz plain in Central Morocco, schistosomiasis was introduced after the construction of the Tessaout Amont irrigation system in the early 1970s. The typical design of this canal irrigation system, with elevated semi-circular conduits as secondary and tertiary canals, is based on upstream control and the water is distributed in rotation. Inverted siphons, consisting of two square boxes connected by an underground pipe, have been constructed to convey the water under roads or tracks. The boxes contain stagnant water and provide excellent breeding sites for Bulinus truncatus , the intermediate snail host of schistosomiasis.A cross-sectional survey showed that especially inverted siphons on tertiary canals harbour high densities of B.truncatus . A length profile study along one secondary canal and four of its tertiaries showed that conditions near the tail end of canals, especially in the downstream siphon boxes, are most favourable to the intermediate snail host. The transmission of schistosomiasis in Tessaout Amont is concentrated at these siphons as, in the absence of other sources, water from the boxes is used for all kinds of agricultural and domestic purposes, inducing frequent water contact.Three environmental control options have been studied. Regular emptying and cleaning of siphon boxes had a limited effect on densities of Bulinus truncatus snails and eggs. Creating a dark environment by covering siphon boxes with iron plates proved to be much more effective in reducing B.truncatus populations. Some of the covers were equipped with moveable lids to leave the water accessible to the villagers. The third control option concerned measures to increase the water flow velocity in siphons. Combining flow velocities with the duration of the flow results in a mean annual flow velocity. According to literature, above a critical value of 0.042 m/s, no B.truncatus snails are to be found in siphon boxes. In siphons with a lower mean annual flow velocity, this critical value can be obtained by reducing the inner dimensions of the siphon boxes, thus increasing the water flow velocity. However, in experiments with such smaller siphon boxes, the siphons were quickly repopulated with B.truncatus . Better results might be achieved by redefining the critical value. However, the small diameter siphons generate higher energy losses. Consequently, such siphons can only be applied in a layout where access to the fields is guaranteed through simple bridges over the drains, which significantly reduces the number of required siphons.</p

A review of the understanding of uncertainty in a flood forecasting system and the available methods of dealing with it

The increased availability and application of probabilistic weather forecasts in flood forecasting means that the uncertainty arising from the precipitation forecast can be assessed. This has led to a wider interest in how uncertainty is affecting flood forecast systems. In literature there are general techniques and principles available on how to deal with uncertainty. However, there are no of well-accepted guidelines on the implementation these principles and techniques. There is neither coherent terminology nor a systematic approach which means that it is difficult and perhaps even impossible to assess the characteristics and limitations of uncertainty quantification methods. Selecting the most appropriate method to match a specific flood forecasting system is therefore a challenge. The main findings of this review are that there are remaining mathematical and theoretical challenges in uncertainty quantification methods and that this leads to the use of assumptions which in turn could lead to a misrepresentation of the predictive uncertainty

Small multi-purpose reservoir ensemble planning

People living in arid areas with highly variable rainfall, experience droughts and floods and often have insecure livelihoods. Small multi-purpose reservoirs are a widely used form of infrastructure for the provision of water. They supply water for domestic use, livestock watering, small scale irrigation, and other beneficial uses. The reservoirs are hydrologically linked by the streams that have been dammed. Although reservoirs store a large quantity of water and have a significant effect on downstream flows, they have rarely been considered as systems, with synergies and tradeoffs resulting from the number and density of their structures. Often reservoirs were constructed in a series of projects funded by different agencies, at different times, with little or no coordination among the implementing partners. A significant number are functioning sub-optimally and/or are falling into disrepair. This indicates that there is room for improvement in the planning, operation, and maintenance of small reservoirs. The water management institutions in Volta, Limpopo, and Sao Francisco Basins are being revamped to better serve their constituencies. We have an opportunity to collaborate with government officials, stakeholders, and farmers who are actively looking for ways to improve the planning process. The Small Reservoir Project team developed a tool kit to support the planning, development, and management of small reservoir ensembles on the basin level and the use of small multi-purpose reservoirs that are properly located, well designed, operated and maintained in sustainable fashion, and economically viable on the local/community level. There are tools to improve intervention planning, storage estimation and the analysis of the hydrology, ecology and health of small reservoirs. There ara also tools for the analysis of institutional and economic aspects of the reservoirs. The toolkit not only includes the necessary analytical instruments, but also a set of process oriented tools for improved participatory decision making. The Tool Kit is meant to be a living “document” with additional tools and experiences to be added as they are developed

The role of human activities in the transmission of stomach flukes Paramphistomum microbothrium (Fishoeder, 1901) (Trematoda: Paramphistomatidae) in Tessaout amont irrigation scheme, Central Morocco

Une prospection menée au niveau des différentes structures du réseau d’irrigation dans la région de Tessaout Amont a montré l’existence de neuf espèces de mollusques d’eau douce appartenant à cinq familles. Les canaux d’irrigation traditionnels sont des sites de transmission de la schistosomose à Schistosoma haematobium à l'homme et de la distomatose à Fasciola hepatica chez les ovins et les caprins du Haouz. Plus récemment, la transmission de la paramphistomose a été également rapportée pour la première fois dans le Haouz au Maroc. La présente étude montre que l’infestation de Bulinus truncatus hôte intermédiaire de Paramphistomum microbotrium s’effectue dans des siphons inaccessibles au bétail qui en constitue l’hôte définitif. Il s’est avéré que les oeufs du parasite sont mis en contact du mollusque suite au rinçage des viscères de ruminants abattus par les bouchers et par les riverains dans l’eau des canaux et des siphons. Les implications de ce résultat sur les possibilités de lutte contre cette maladie sont discutées

Environmental, social, and WASH factors affecting the recurrence of cholera outbreaks in displacement camps in Northeast Nigeria: a rapid appraisal

In 2021, Nigeria witnessed a severe cholera outbreak that affected Borno state, in which more than 1,600,000 internally displaced persons (IDPs) resided at the time. This rapid appraisal explored factors that facilitate the recurrence of cholera outbreaks in sites hosting IDPs in Northeast Nigeria. Semi-structured interviews were conducted with water, sanitation, and hygiene (WASH), management, and healthcare personnel working in ten displacement camps in Borno state. The interviews were complemented by transect walks and field observations, measurements of free residual chlorine levels, and publicly available data published by the International Organization for Migration Displacement Tracking Matrix. The recurrence of cholera outbreaks appears to be facilitated by substantial interactions between IDPs and host communities, and suboptimal WASH services in camps. Of particular concern, IDP camps are exposed to extreme weather-related events that damage facilities and subsequently affect WASH practices. WASH services in camps may likewise be severely hindered by an influx of new arrivals. In conclusion, we emphasize the importance of expanding WASH activities to host communities and developing site-specific WASH interventions and chlorination targets. Practical recommendations are needed for the prevention and control of outbreaks following extreme weather-related events and population influxes

Operational decision support system for sustainable water resource management for Sungai Selangor

The Selangor River lies on the west coast of Peninsular Malaysia, 70 km north of Kuala Lumpur. The Selangor catchment area is approximately 2000 km2 and has two major dams located in the upstream part of the catchment: Sungai Selangor Dam and Sungai Tinggi Dam. Lembaga Urus Air Selangor (LUAS) is the Malaysian government agency responsible for water resources management of the Selangor catchment, their main challenge being to balance an increase in water demand, whilst trying to manage the catchment’s environmental state. Key to this is the amount of water that is being released from the two reservoirs. The current manual decision-making process (based on staff experience) does not provide LUAS with the efficiency and accuracy that is required in a catchment where sustainability is key and water resources are not always abundant. A solution was required to improve the management of the current resources, thus reducing the need for the costly and environmentally contentious development of new infrastructure. The operational Decision Support System (DSS) for sustainable water resources management of the Sungai Selangor catchment is a non-structural tool developed to support LUAS in optimising the reservoir releases and water abstractions in the catchment; it is also known as LUAS Intelligent Support System (LiSS). LiSS is a fully automated system that is driven by a combination of live, telemetered gauged data from various sources including the InfoBanjir telemetry database and Numerical Weather Prediction (NWP) rainfall forecasts from the Malaysian Meteorological Department (MMD). Simulations are carried out automatically on an hourly basis, to calculate and forecast whether flows at Bestari Jaya Barrage near the main abstraction location (SSP1) are being maintained at the required levels. If the required flows are not met, being either too high or too low, the model is re-run using an adjusted reservoir release time series. LiSS should also be able to help LUAS in future increase the sustainability of management of water resources in the Selangor catchment. This paper describes the approach developed to support LUAS meet this objective, in a manner that can be used in real-time, and which can be transferred to other catchments in future. The advantages and disadvantages of potentially expanding this system to use ensemble forecasts, data assimilation and optimisation algorithms are discussed, along with suggestions for further research

Biting the hand that feeds: anthropogenic drivers interactively make mosquitoes thrive

Anthropogenic stressors on the environment are increasing at unprecedented rates and include urbanization, nutrient pollution, water management, altered land use and climate change. Their effects on disease vectors are poorly understood. A series of full factorial experiments investigated how key human induced abiotic pressures, and interactions between these, affect population parameters of the cosmopolitan disease vector, Culex pipiens s.l. Selected pressures include eutrophication, salinity, mean temperature, and temperature fluctuation. Data were collected for each individual pressure and for potential interactions between eutrophication, salinization and temperature. All experiments assessed survival, time to pupation, time to emergence, sex-ratio and ovipositioning behavior. The results show that stressors affect vector survival, may speed up development and alter female to male ratio, although large differences between stressors exist to quite different extents. While positive effects of increasing levels of eutrophication on survival were consistent, negative effects of salinity on survival were only apparent at higher temperatures, thus indicating a strong interaction effect between salinization and temperature. Temperature had no independent effect on larval survival. Overall, increasing eutrophication and temperatures, and the fluctuations thereof, lowered development rate, time to pupation and time to emergence while increasing levels of salinity increased development time. Higher levels of eutrophication positively impacted egg-laying behavior; the reverse was found for salinity while no effects of temperature on egg-laying behavior were observed. Results suggest large and positive impacts of anthropogenically induced habitat alterations on mosquito population dynamics. Many of these effects are exacerbated by increasing temperatures and fluctuations therein. In a world where eutrophication and salinization are increasingly abundant, mosquitoes are likely important benefactors. Ultimately, this study illustrates the importance of including multiple and combined stressors in predictive models as well as in prevention and mitigation strategies, particularly because they resonate with possible, but yet underdeveloped action plans. NWONWA.1160.1S.210Environmental Biolog

Flood forecasting and warning for Muar River: non-structural measures for flood mitigation

The Muar River catchment has repeatedly suffered prolonged, significant flood events which have caused widespread disruption and impacts to residents, businesses and infrastructure; the impacts have been exacerbated by considerable rapid development over the past decade, which has modified the flow regimes and flooding mechanisms. To help prepare for, and mitigate, the effects of future floods, the Malaysian government is implementing a range of flood management projects, which will provide an integrated approach based on structural and non-structural measures. The integrated Flood Forecasting and River Monitoring system (iFFRM) for the river Muar is a key non-structural measure that has been recently implemented. The government’s Department of Irrigation and Drainage (DID) is responsible for providing a flood forecasting and warning service to the public; the iFFRM is a tool designed to enable effective decision support by DID. The iFFRM is a fully automated system that is driven by a combination of live, telemetered gauged data from DID’s own InfoBanjir database, spatial rainfall radar data, and Numerical Weather Prediction (NWP) rainfall forecasts from the Malaysian Meteorological Department. Hourly simulations are carried out automatically, to forecast water levels and flows in the river channels, and to map the flood inundation process within the flood plains. Simulation results are used to warn DID staff so that immediate action can be taken to provide an effective and proactive emergency response. Results are also passed to the project website, and dedicated smartphone application, enabling forecasts to be disseminated more widely. A parallel analytical modelling network can take over the forecasting role should the primary iFFRM system fail. Ongoing structural measures for flood mitigation are captured through a flexible modelling approach that can incorporate model updates to reflect real changes in the catchment, complementing the structural measures being implemented by DID and ensuring a sustainable solution

Mainstreaming biodiversity where it matters most

This report presents the result of applying the framework in five cases in or on the cross roads between agriculture, forestry and fisheries where considerable pressure on biodiversity is exerted. The cases were selected based on several criteria with the aim that they together cover as broad span as possible of: Relevance for biodiversity (from having very clear impacts to much more uncertain impacts) Governance levels (including both local, national, global levels) Governance context (type of actors, type of norms etc.) Regions (continents and eco‐climatic zones

How effective are on-farm conservation land management strategies for preserving ecosystem services in developing countries? A systematic map protocol

Background An extensive body of literature in the field of agro-ecology claims to show the positive effects that maintenance of ecosystem services can have on sustainably meeting future food demand, by making farms more productive and resilient, and contributing to better nutrition and livelihoods of farmers. In Africa alone, some research has estimated a two-fold yield increase if food producers capitalize on new and existing knowledge from science and technology. Site-specific strategies adopted with the aim of improving ecosystem services may incorporate principles of multifunctional agriculture, sustainable intensification and conservation agriculture. However, a coherent synthesis and review of the evidence of these claims is largely absent, and the quality of much of this literature is questionable. Moreover, inconsistent effects have commonly been reported, while empirical evidence to support assumed improvements is largely lacking. Objectives This systematic map is stimulated by an interest to (1) collate evidence on the effectiveness of on-farm conservation land management for preserving and enhancing ecosystem services in agricultural landscapes, by drawing together the currently fragmented and multidisciplinary literature base, and (2) geographically map what indicators have been used to assess on-farm conservation land management. For both questions, we will focus on 74 low-income and developing countries, where much of the world’s agricultural expansion is occurring, yet 80% of arable land is already used and croplands are yielding well below their potential. Methods/Design To this end, reviewers will systematically search bibliographic databases for peer-reviewed research from Web of Science, SCOPUS, AGRICOLA, AGRIS databases and CAB abstracts, and grey literature from Google Scholar, and 22 subject-specific or institutional websites. Boolean search operators will be used to create search strings where applicable. Ecosystem services included in the study are pollination services; pest-, carbon-, soil-, and water-regulation; nutrient cycling; medicinal and aromatic plants; fuel wood and cultural services. Outputs of the systematic map will include a database, technical report and an online interactive map, searchable by topic. The results of this map are expected to provide clarity about synergistic outcomes of conservation land management, which will help support local decision-making