This document is the first systematic discussion of the most important lessons of the APPJ Project of the European Union, which was implemented between the years 1993 and 2001. The project was prepared to respond to the emergency health situation of the cholera epidemic of 1991. The proposed project was to comment on building autonomous systems of drinking water in peri-urban areas not served by the SEDAPAL drinking water network. Lessons learned include: 1) It is not enough to build drinking water systems; 2) It is essential to ensure the existence of units that manage the system efficiently. 3) It is important to operate a monitoring program of the autonomous systems in Lima. This document has been divided into five chapters and three annexes. The first chapter presents the background of the project, the features of the proposal and phases their execution. The second deals with processes that led to major improvements in the construction of the autonomous systems of drinking water. The third chapter discusses the various aspects and factors influencing the sustainability of water systems. The fourth chapter discusses the role of institutional actors involved directly or indirectly in the sustainability of building water systems. Finally, the fifth chapter presents conclusions and lessons. The document ends with three annexes: the first is information on costs and volume of sales of systems visited; the second is a summary of the information status of systems visited, and the third is a list of NGOs who have participated in the implementation of the project.

This paper presents new experiences in the province of Andahuaylas, in the Andes of Peru, in a bid to help solve the problem of water supply in rural scattered areas. The central part of the document consists of a study that describes and analyzes the process by which 5 small areas in a scattered rural steeply sloping side of a mountain managed to acquire a sustainable water supply operated by gravity. The study includes 3 chapters. The first chapter examines the water issues in the communities, what solutions developed by the commoners to stock up on water, what are the drawbacks of the traditional system of their drinking water system. The second chapter describes technical aspects of the project, explaining how the technologies employed were the product of the physical and social environment. The third chapter describes the community participation during and after the project.

This document is the first systematic discussion of the most important lessons of the APPJ Project of the European Union, which was implemented between the years 1993 and 2001. The project was prepared to respond to the emergency health situation of the cholera epidemic of 1991. The proposed project was to comment on building autonomous systems of drinking water in peri-urban areas not served by the SEDAPAL drinking water network. Lessons learned include: 1) It is not enough to build drinking water systems; 2) It is essential to ensure the existence of units that manage the system efficiently. 3) It is important to operate a monitoring program of the autonomous systems in Lima. This document has been divided into five chapters and three annexes. The first chapter presents the background of the project, the features of the proposal and phases their execution. The second deals with processes that led to major improvements in the construction of the autonomous systems of drinking water. The third chapter discusses the various aspects and factors influencing the sustainability of water systems. The fourth chapter discusses the role of institutional actors involved directly or indirectly in the sustainability of building water systems. Finally, the fifth chapter presents conclusions and lessons. The document ends with three annexes: the first is information on costs and volume of sales of systems visited; the second is a summary of the information status of systems visited, and the third is a list of NGOs who have participated in the implementation of the project.

Groundwater is an extensive, concealed and inaccessible resource, and (in contrast to surface water) changes in quantity and quality are often very slow processes occurring below large land areas. These changes cannot be determined by simple one-off snapshot surveys alone, and require more elaborate monitoring networks and data interpretation. The primary goal of aquifer management is to control the impacts of groundwater abstraction and contaminant loads, and monitoring aquifer response and quality trends provide key inputs for this goal. The evaluation of groundwater issues and the implementation of management solutions require hydrogeological data that are in part baseline and in part time-variant in character-the collection of the time-variant component is what is usually considered groundwater monitoring. Groundwater monitoring thus comprises the collection, analysis and storage of a range of data on a regular basis according to specific circumstances and objectives.

The geochemical and isotopic composition of surface waters and groundwater in the Velenje Basin, Slovenia, was investigated seasonally to determine the relationship between major aquifers and surface waters, water–rock reactions, relative ages of groundwater, and biogeochemical processes. Groundwater in the Triassic aquifer is dominated by HCO₃–, Ca²⁺, Mg²⁺and δ¹³CDICindicating degradation of soil organic matter and dissolution of carbonate minerals, similar to surface waters. In addition, groundwater in the Triassic aquifer has δ¹⁸O and δD values that plot near surface waters on the local and global meteoric water lines, and detectable tritium, likely reflecting recent (<50 years) recharge. In contrast, groundwater in the Pliocene aquifers is enriched in Mg²⁺, Na⁺, Ca²⁺, K⁺, and Si, and has high alkalinity and δ¹³CDICvalues, with low SO₄²–and NO₃–concentrations. These waters have likely been influenced by sulfate reduction and microbial methanogenesis associated with coal seams and dissolution of feldspars and Mg-rich clay minerals. Pliocene aquifer waters are also depleted in¹⁸O and²H, and have³H concentrations near the detection limit, suggesting these waters are older, had a different recharge source, and have not mixed extensively with groundwater in the Triassic aquifer.

The study of the different biotic and abiotic processes involved in the current formation of Fe-stromatolites in rivers affected by acid mine drainage (AMD) is essential not only to understand this unique and extreme environment, but also to achieve a better understanding of the past iron formation on the Earth and on Mars. The Fe-stromatolites studied in the highly polluted AMD in Tharsis, SW Spain, revealed a unique mineral assemblage with jarosite and rostite as the most unexpected Fe and Al phases and goethite and schwertmannite as the main constituents. Seasonal variations in this region greatly affected the composition of the precipitates and the distribution of diatoms within the Fe-stromatolites. Drought and flood events were also recognized in the sedimentary textures and in the mineral assemblages observed of particular layers within the Fe-stromatolites. The characterization of the chemical and mineralogical composition of Fe-stromatolites in Tharsis as well as the different formation mechanisms proposed complement the existing literature on newly-formed Fe-stromatolites and provides new observations to increase our understanding of those extreme environments.

[ES] El silicio (Si) es el segundo elemento más abundante en la Tierra, y a pesar de no considerarse un nutriente mineral esencial, numerosas referencias bibliográficas proporcionan evidencias que respaldan sus efectos beneficiosos en las plantas, especialmente bajo condiciones de estrés, como la sequía. El Si es absorbido por las plantas en forma de ácido silícico Si(OH)4 y se deposita principalmente en la pared celular, donde componentes específicos desencadenan la precipitación de SiO2 en el apoplasto en forma sólida, como fitolitos, a través de un proceso llamado biosilicificación. Según la "hipótesis de obstrucción apoplástica" de Coskun et al. (2019), la biosilicificación en el apoplasto reduce las pérdidas de agua a través de la transpiración y, por lo tanto, mejora el rendimiento del cultivo bajo condiciones de estrés por sequía. Además, se ha documentado que la aplicación de silicio mejora el potencial hídrico de las hojas en presencia de condiciones de estrés hídrico (Matoh et al., 1991). Se propone que una doble capa compuesta de sílice y cutícula, formada en el tejido epidérmico de las hojas, es responsable del aumento del potencial hídrico observado, aunque aún no se ha comprendido completamente su mecanismo de acción. Mejorar la capacidad de las plantas para retener agua durante los períodos de sequía no solo podría aumentar la resiliencia de los cultivos, sino también mejorar la eficiencia en el uso del agua en la agricultura y avanzar hacia prácticas agrícolas más sostenibles. Esta tesis investiga el impacto de la fertilización con silicio en la capacidad de almacenamiento de agua en las hojas de trigo. El trigo de primavera (Triticum aestivum L. cv. Expectum) se cultiva hidropónicamente bajo seis tratamientos, combinando tres concentraciones de silicio con dos condiciones de estrés (sin estrés y sequía inducida por PEG). Los resultados del estudio contradicen las hipótesis iniciales, mostrando que el tratamiento con silicio no mejoró el crecimiento ni el contenido relativo de agua (RWC) en las plantas de trigo bajo estrés por sequía, y solo redujo parcialmente el potencial hídrico de las hojas. Además, fluctuaciones inesperadas en el pH de las soluciones tratadas con silicio podrían haber afectado los resultados. . | [EN] Silicon (Si) is the second most abundant element on Earth, and despite not being considered an essential mineral nutrient, an expanding body of literature provides mounting evidence substantiating its beneficial effects on plants, especially under stress conditions such as drought. Si is taken up by plants as silicic acid Si(OH)4 and it is deposited mostly in the cell wall where specific components trigger SiO2 precipitation in the apoplast in solid form, as phytoliths, through a process called biosilification. According to the apoplastic obstruction hypothesis by Coskun et al. (2019) the biosilification in the apoplast reduces water losses through transpiration and therefore improves the crop performance under drought stress conditions. Moreover, the application of silicon is documented to improve leaf water potential in the presence of water stress conditions (Matoh et al., 1991). It is proposed that a dual layer composed of silica and cuticle formed on the leaf epidermal tissue is accountable for the observed elevated water potential while an understanding of its mechanism of action has not been provided yet. Improving plants' ability to retain water during drought periods could not only increase crop resilience but also enhance water use efficiency in agriculture and move towards more sustainable agricultural practices. This thesis investigates the impact of silicon fertilization on the water storage capacity of wheat leaves. Spring wheat (Triticum aestivum L. cv. Expectum) is grown hydroponically under six treatments, combining three silicon concentrations with two stress conditions (no stress and PEG-induced drought). The study's findings contradict the initial hypotheses, showing that silicon treatment did not improve wheat growth or relative water content (RWC) under drought stress, and only partially reduced leaf water potential. Additionally, unexpected pH fluctuations in the silicon-treated solutions may have influenced the results. | Pérez Rodríguez, M. (2024). Can silicon enhance the ability of wheat (Triticum aestivum L.) leaves to retain water under drought conditions?. Universitat Politècnica de València. http://hdl.handle.net/10251/208873