Abstract In the upper basin of the Medellín River (Colombia) a hydrologic study was carried out to analyze the rainfall-runoff relationships in an event-scale, for the estimation of the maximum streamflow regime associated with different return periods in the basin and its tributary sub-basins, through hydrological modeling that considers the existence of climate change. This study is composed of the characterization of the basin of the study area, as well as the hydrological characterization, which includes the analysis of measured data with high temporal resolution of precipitation and the river levels. Different methods were considered to obtain the necessary information for the execution of a semi-distributed hydrological modeling activities, using the HEC-HMS. The model was calibrated by the simulation of 5 maximum streamflow events of the year 2021 and then it was run with different configurations of the antecedent moisture condition, rainfall-runoff models and stationary and non-stationary conditions (in rainfall), the latter to assess potential effects of the climate change. According to the results, the relative differences between the modeling cases with stationary and non-stationary conditions are, on average, negligible, with values between 3 and 5% in the considered cases, with the non-stationary cases having higher magnitudes of streamflow.

Resumen En la cuenca alta del río Medellín (Colombia) se realizó un estudio hidrológico con el fin de analizar las relaciones lluvia-escorrentía a escala de eventos en esta zona, para la estimación del régimen de caudales máximos asociados a diferentes períodos de retorno en la cuenca del río y subcuencas tributarias, mediante modelación hidrológica considerando cambio climático. Este estudio está compuesto por la caracterización de la cuenca de la zona de estudio, así como la caracterización hidrológica, la cual abarca el análisis de datos medidos con alta resolución temporal de precipitación y niveles del río. Se tienen en cuenta también diferentes métodos para la obtención de la información necesaria para la correcta ejecución de actividades de modelación hidrológica semidistribuida, utilizando el software HEC-HMS. El modelo fue calibrado simulando 5 eventos máximos de caudal del año 2021, y luego ejecutado con distintas configuraciones de condición de humedad antecedente, modelos lluvia-escorrentía y la consideración de condiciones estacionarias y no estacionarias (en la precipitación), estas últimas con el fin de evaluar potenciales efectos debido al cambio climático. Según los resultados obtenidos, las diferencias relativas entre los caudales máximos obtenidos simulando las curvas IDF estacionarias y no estacionarias (estos últimos siendo usados como proxy para condiciones de cambio climático) no presentan diferencias significativas y oscilan entre 3-5%,obteniéndose las mayores magnitudes en los casos no estacionarios.

Abstract Introduction The lama-bordo systems (LBS) are built in natural watercourses and favor retention of sediment and runoff moisture for the development of agricultural activity. Objective To obtain a model for predicting the volume of soil permanently captured by LBS, based on the morphometric and hydrological characteristics of the micro-watersheds where they have prevailed in the Mixteca Alta of Oaxaca, Mexico Materials and methods The study was carried out in 27 sites where morphometric parameters and hydrological indexes were determined to obtain the volume prediction model by multiple linear regression (backward elimination technique). Results and discussion The systems studied were found in micro-watersheds under conditions that favor sediment transport: elongated shape, areas smaller than 2 km2 with 1st and 2nd order streams, at altitudes above 2 000 m and slopes greater than 10 %. Twelve morphometric parameters and three hydrological indexes characterize these micro-watersheds and explain the physical conditions that allow their establishment, but only four (micro-watershed area, average slope of the mainstream, topographic wetness index and sediment transport index) explain the cumulative sediment volume (R2 = 0.85, P < 0.001). Conclusions The model evaluated for volume estimation is reliable for application at sites under similar conditions.

Resumen Introducción Los sistemas lama-bordo (SLB) se construyen en cauces naturales y favorecen la retención de sedimentos y humedad del escurrimiento para el desarrollo de la actividad agrícola. Objetivo Obtener un modelo de predicción de volumen de suelo captado por los SLB en forma permanente, a partir de las características morfométricas e hidrológicas de las microcuencas donde estos han prevalecido en la Mixteca Alta de Oaxaca, México. Materiales y métodos El estudio se hizo en 27 sitios donde se determinaron parámetros morfométricos e índices hidrológicos que permitieron obtener el modelo de predicción de volumen mediante regresión lineal múltiple tipo backward stepwise. Resultados y discusión Los sistemas estudiados se encontraron en microcuencas bajo condiciones que favorecen el transporte de sedimentos: forma alargada, áreas menores de 2 km2 con corrientes de 1° y 2° orden, en altitudes superiores a los 2 000 m y pendientes mayores de 10 %. Doce parámetros morfométricos y tres índices hidrológicos caracterizan dichas microcuencas y explican las condiciones físicas que permiten su establecimiento, pero solo cuatro (área de la microcuenca, pendiente media de la corriente principal, índice topográfico de humedad e índice de transporte de sedimentos) explican el volumen de sedimento acumulado (R2 = 0.85, P < 0.001). Conclusiones El modelo evaluado para la estimación de volumen es confiable para su aplicación en sitios bajo condiciones similares.

Resumo O estudo fundamenta-se em uma análise geral das geociências do colapso nos campos de cultivo de Santa María Zacatepec, na cidade de Juan C. Bonilla, México. A técnica de sensoriamento remoto é aplicada no desenvolvimento, permitindo a interpretação de combinações de bandas e a determinação da geometria, geologia, geomorfologia e cartografia do local. É apresentada uma análise resumida do trabalho realizado, além de modelos de simulação do gasto hidrológico e da aceleração da água nos taludes estruturais de escoamento. Esses dados foram utilizados para o mapeamento final e a modelagem gráfica. Foi realizado um estudo geomorfológico, geológico e topográfico do local, utilizando técnicas telemétricas aéreas e de satélite. Também foi utilizado um software especializado para levantamentos geodésicos e mapeamento em modelos 2D e 3D da área de análise. Os levantamentos do local foram realizados com o objetivo de conhecer o formato da estrutura e identificar áreas de risco potencial para a população próxima ao colapso. Foram obtidas ortofotos para calcular e determinar a inclinação por distância-elevação, aceleração-altura, fluxo de água e força, o que serviu para concluir as possíveis causas que levaram ao colapso e para ter dados técnicos suficientes que foram compartilhados com as autoridades de proteção civil.

Abstract This paper presents a general analysis from the geosciences of structural collapses. The analysis was conducted in the crop fields of Santa María Zacatepec, in the city of Juan C. Bonilla, Mexico. The analysis implemented the Remote Sensing technique, facilitating the interpretation of band combinations and determining the geometry, geology, geomorphology and cartography of the site under study. A summary analysis of the work performed is presented, in addition to showing simulation models of the hydrological outflow and water acceleration in the runoff structural slopes, data that were used for the final mapping and graphic modeling. A geomorphological, geological, and topographical study of the site was conducted, using satellite and aerial telemetric techniques. Specialized software was also used for geodetic surveys, mapping in 2D and 3D models of the analysis area. Surveys of the site were carried out to determine the shape of the structure and identify potentially risk areas for the population near the collapse events. Orthophotos were obtained to calculate and determine the slope by distance-elevation, acceleration-height, water flow and force, which served to conclude the possible causes that led to the collapses and have sufficient technical data that were shared with the civil protection authorities.

Resumen El trabajo se basa en un análisis general desde las geociencias del colapso en los campos de cultivo de Santa María Zacatepec, de la ciudad Juan C. Bonilla. En el desarrollo se aplica la técnica de Percepción Remota, permitiendo interpretar combinaciones de bandas y determinar la geometría, geología, geomorfología y cartografía del sitio. Se presenta un análisis resumido del trabajo que se realizó, además de mostrar modelos de simulación del gasto hidrológico y la aceleración del agua en las pendientes estructurales de escorrentía, datos que se usaron para la cartografía y modelado gráfico finales. Se realizó un estudio geomorfológico, geológico y topográfico del lugar, con técnicas telemétricas satelitales y aéreas; también se utilizó software especializado que se aplicó para levantamientos geodésicos, realizando cartografía en modelos 2D y 3D del área de análisis. Las prospecciones del lugar se realizaron con el objetivo de conocer la forma de la estructura e identificar áreas potencialmente riesgosas para la población cercana al colapso. Se obtuvieron ortofotos para calcular y determinar la pendiente por distanciaelevación, la aceleración-altura, el gasto y la fuerza del agua; que sirvió para concluir las posibles causas que ocasionaron el colapso, y contar con datos técnicos suficientes que se compartieron con las autoridades de protección civil.

Abstract In recent years, Unmanned Aerial Vehicles (UAVs) have presented a variety of applications. Recent studies show their advantages when quantifying areas for storm runoff estimation. However, there are uncertainties about their actual range. Therefore, the objective of this study was to estimate the volume of rainfall captured by roofs using UAVs. The methodology consisted of selecting a study area composed of a variety of canopies, in which the areas were digitally measured, the latter by processing images captured by UAV. For the calculation of runoff volume, the average monthly precipitation data of the last 11 years were taken, and the Runoff Coefficients (Ce) reported in the literature were considered. Then, the mean monthly runoff volume was calculated for each canopy. The results show that the roofs studied (Coliseum - Library) have the capacity to capture an annual volume of 2237.75 m3. With an average volume of 406.74 m3 during the rainy season (November to March) and 29.15 m3 during the dry season (April to October). Although the use of UAV allows determining one of the values within the runoff volume calculation, in order to achieve a more accurate result, it is necessary to analyze and evaluate the other variables (Ce and precipitation).

Resumen En los últimos años, los Vehículos Aéreos No Tripulados (VANT) han presentado una variedad de aplicaciones. Estudios recientes demuestran sus ventajas al momento de cuantificar áreas para la estimación de escorrentía pluvial. Sin embargo, existen incertidumbres sobre su alcance real. Ante ello, el objetivo del estudio es estimar el volumen pluvial captado por cubiertas mediante VANT. La metodología consistió en seleccionar una zona de estudio compuesta por una variedad de cubiertas, en el que las áreas fueron medidas digitalmente, esta última por medio del procesamiento de imágenes captadas por VANT. Para el cálculo de volumen de escurrimiento, se tomaron los datos de precipitación media mensual de los últimos 11 años, y se consideraron los Coeficientes de Escorrentía (Ce) reportados en la literatura. A continuación, se calculó el volumen de escurrimiento medio mensual para cada cubierta. Los resultados muestran que las cubiertas estudiadas (Coliseo - Biblioteca), tienen la capacidad de captar un volumen anual de 2237.75 m3. Con un volumen promedio de 406.74 m3 durante la época lluviosa (noviembre a marzo) y 29.15 m3 en la época seca (abril a octubre). Aunque el uso de VANT permite determinar uno de los valores dentro del cálculo de volumen de escorrentía, para lograr un resultado más exacto, es preciso analizar y evaluar las otras variables (Ce y precipitación).

Abstract: The study was conducted at the Jalpan de Serra dam, Querétaro, Mexico. In a mountain watershed with a history of artisanal mining activity in the upper part, runoff feeds the reservoir, transporting mining tailings. The Jalpan dam has been used for drinking water supply, agricultural irrigation activities and recreational purposes as a Ramsar site. The reason for the study has been the relevance and social impact of the reservoir sediments as a source of diffuse pollution. The objective was to determine the concentration of arsenic, cadmium and lead in the sediment and to evaluate the level of risk to human health and the environment. The methodology consists of the analysis by atomic absorption carried out in three sites sampled in the superficial layer of 10 cm depth, samples obtained with a PVC tube of 7 cm diameter, identified, preserved for transfer and digested with nitric acid. The results show mean arsenic concentrations of 4.278 mg/kg, cadmium 0.323 mg/kg and lead 4.873 mg/kg. In conclusion, the sediment analyzed does not represent a risk to human health or the environment of the reservoir according to NOM-147-SEMARNAT/SSA1-2004. This investigation demonstrates the lack of a policy or standard that establishes permissible limits for heavy metals in sediment.

Resumen: El estudio ha sido realizado en la presa Jalpan de Serra, Querétaro, México. En una cuenca de montaña con antecedentes de actividad minera artesanal en la parte alta, la escorrentía alimenta el embalse, transportando relaves mineros. La presa Jalpan se ha empleado para abastecimiento de agua de consumo humano, actividades de riego agrícola y fines recreativos como sitio Ramsar. El motivo de estudio ha sido la relevancia e impacto social que tienen los sedimentos del embalse como fuente de contaminación difusa. El objetivo ha sido conocer la concentración de arsénico, cadmio y plomo en el sedimento y evaluar el nivel de riesgo para la salud humana y del ambiente. La metodología consiste en el análisis por absorción atómica realizada en tres sitios muestreados en la capa superficial de 10 cm de profundidad, muestras obtenidas con un tubo de PVC de 7 cm de diámetro, identificadas, conservadas para su traslado y digeridas con ácido nítrico. Los resultados muestran concentraciones medias en arsénico de 4.278 mg/kg, cadmio 0.323 mg/kg y plomo 4.873 mg/kg. En conclusión, el sedimento analizado no representa riesgo para la salud humana o entorno del embalse según la norma NOM-147-SEMARNAT/SSA1-2004. Esta investigación evidencia la falta de una política o norma que establezca los límites permisibles de metales pesados en sedimentos.

Abstract Urban trees play an important role within cities due to the environmental services they provide and their contribution to mitigating the current climate crisis. In this context, the objective of this study was to evaluate the tree vegetation of five public parks in the Texcoco de Mora municipality in order to estimate the environmental services they provide. A census was carried out per park and the data were processed through the i-Tree® Eco v6 software. 1 325 individuals from 23 families and 37 genera were recorded with a richness of 55 species in the five parks, an average density of 157 trees ha-1 and a total of 242.6 megagrams of carbon storage with a carbon capture of 10.5 Mg year-1. The avoided rain runoff was 481 m3 year-1 and the value represented by these environmental services is MXN $894 514.93 for carbon storage, MXN $38 650 annually for carbon capture, and MXN $481.93 for runoff. The replacement value of the trees reaches MXN $24 408 534. A tree cover of 30 485 m2 was estimated, which represents a factor of 0.86 m2 inhabitant-1. It is concluded that Texcoco is below the recommended factor of trees per inhabitant proposed by the UN. It is necessary to study the green areas, medians, alignment trees and community parks, to achieve a more complete panorama of the municipality.

Resumen El arbolado urbano desempeña un papel importante dentro de las ciudades por los servicios ambientales que provee y por su contribución a la mitigación de la actual crisis climática. En ese contexto, el objetivo del presente estudio consistió en evaluar la vegetación arbórea de cinco parques públicos del municipio Texcoco de Mora a fin de estimar los servicios ambientales que proporcionan. Se realizó un censo por parque y se procesaron los datos a través del software i-Tree ® Eco V6. Se registraron 1 325 individuos de 23 familias y 37 géneros con una riqueza de 55 especies en los cinco parques, una densidad promedio de 157 árboles ha-1 y un total de 242.6 megagramos de almacenamiento de carbono con una captura de 10.5 Mg año-1. El escurrimiento de lluvia evitado fue de 481 m3 año-1 y el valor que representan estos servicios ambientales en pesos es de MXN $894 514.93 para el almacenamiento de carbono, MXN $38 650 anuales para la captura del mismo y MXN $481.93 para el escurrimiento. El valor de sustitución del arbolado es de MXN $24 408 534.00. Se estimó una cobertura arbórea de 30 485 m2, lo cual representa un factor de 0.86 m2 habitante-1. Se concluye que Texcoco está por debajo del factor recomendado de arbolado por habitante propuesto por la ONU. Es necesario estudiar las áreas verdes, camellones, árboles de alineamiento y parques comunitarios para tener un panorama del municipio más completo.

The demand for macadamia nut production worldwide has led to increased use of pesticides and chemicals for pest and disease control. Reservoirs in these macadamia farming sectors are at risk, since these chemicals can enter and contaminate the water through direct application, runoff, and atmospheric deposition, subsequently negatively affecting aquatic organisms. The current study investigated macroinvertebrate colonisation and succession associated with two macadamia orchards and two communal area reservoirs. The potential effects of stressors from these land uses was tested for and compared using stone substrates over a 6-week period. Stone substrates from both reservoir types were abundantly colonised over time and the total macroinvertebrate taxa and abundance showed an increasing trend across the sampled weeks, with macadamia orchards having the highest number of macroinvertebrate taxa. Strong ecological succession was observed across reservoirs, with the initial succession of early colonisers - i.e., Chironominae (collector-gatherers), Ostracoda (collector-filterers) and Anax sp. (predator) within communal area reservoirs, and Chironominae, Ostracoda and Radix natalensis (scrapers) in macadamia orchard reservoirs - followed by predatory colonisers such as Gyrinidae larvae, Trithemis sp. (macadamia orchard reservoirs), and Ranatra sp. (communal area reservoirs). Macroinvertebrate community structure differed significantly across sites and weeks, with no similarity being observed for communities across the different reservoirs. Redundancy analyses further highlighted 11 sediment chemistry variables (i.e., pH, resistivity, P, K, Na, Ca, Mg, Cu, B, Fe and S) which were significantly related to macroinvertebrate community structure. Thus, sediment variables were found to be better predictors of macroinvertebrate community structure in macadamia orchard reservoirs than communal area reservoirs. Consequently, we concluded that differences in colonisation ability among taxa and environmental stressors were important factors driving succession. These results add to the understanding of the macroinvertebrate colonisation processes and environmental stressors within agricultural landscapes, which can aid in the development of conservation management of freshwater ecosystems.

Resumen: Los nutrientes, como el nitrógeno y el fósforo generan, entre otros impactos, la eutrofización en los cuerpos de agua. Estos impactos son principalmente causados por actividades agrícolas como la ganadería, debido a la aplicación de fertilizantes y/o al estiércol de las vacas. Los nutrientes transportados por la escorrentía llegan a los cuerpos de agua y generan contaminación. Esta problemática ha sido abordada desde la década de los 60, no obstante, se ha logrado poco avance en este tema. Los avances están relacionados con la estimación del aporte de nutrientes de forma teórica y a través de simulaciones, debido a los altos costos que implica tomar datos en el campo. También se han realizado esfuerzos en la implementación de Buenas Prácticas de Gestión para el manejo de las fuentes no puntuales, pero existe poca evidencia de la eficiencia de cada una de estas prácticas. Por otro lado, pese a la falta de información científica necesaria para formular políticas, se ha demostrado que la vía normativa puede ser el mejor mecanismo para controlar la contaminación por fuentes no puntuales. En este artículo, se presenta una revisión de estos tres componentes luego del análisis bibliométrico, estableciendo lo que se conoce actualmente y las brechas de información. Primero, se abordan los avances en la estimación del aporte de las fuentes no puntuales, segundo se presentan las Buenas Prácticas de Gestión, y tercero, se exponen los avances en materia de políticas para el control de la contaminación no puntual.

Abstract: Nutrients, like nitrogen and phosphorus generate, among other impacts, eutrophication in water bodies. These impacts are mainly caused by agricultural activities such as livestock farming, due to the application of fertilizers and/or cow manure. The nutrients transported by runoff reach water bodies and generate pollution. This issue has been addressed since the 1960s; however, little progress has been made in this area. The progress is related to estimating nutrient contributions theoretically and through simulations, due to the high costs of collecting field data. Efforts have also been made to implement Good Management Practices for the management of non-point sources, but significant efficiency for each of these practices has not been demonstrated. On the other hand, despite the lack of necessary scientific information to formulate policies, it has been shown that the regulatory route can be the best mechanism for controlling non-point source pollution. This article presents a review of these three components after a bibliometric analysis, establishing what is currently known and the information gaps. First, advances in estimating the contributions of non-point sources are addressed, second Good Management Practices are presented, and third advances in policies for controlling non-point source pollution are discussed.

Resumen: El tránsito de avenidas por lo general es usado en el análisis y evaluación de inundaciones, sin embargo, ha sido poco estudiado en la extensión y determinación de caudales. Por ello, esta investigación tuvo por objetivo generar caudales aplicando un método simple de tránsito de avenidas conocido como Muskingum a nivel mensual, en la cuenca La Leche de Perú. Se escogió la cuenca en mención, pues en los últimos 40 años ha sufrido grandes inundaciones, viéndose afectada gran parte de la población, terrenos de cultivo e infraestructura local, por lo que se requiere abordar su estudio. La metodología fue del tipo aplicada y de diseño no experimental comparativo. Debido a que el tránsito de avenidas emplea los parámetros de proporcionalidad de volumen y ponderación del tránsito en intervalos de tiempo definido, se creyó conveniente usar indicadores estadísticos para optimizar la comparación de los caudales registrados en las estaciones hidrométricas y los hidrogramas de la simulación de un modelo hidrológico tipo precipitación-escorrentía para diferentes períodos de retorno, obteniéndose significativos resultados en cada caso, según la correlación de Pearson, el criterio de Schultz, el criterio de Nash-Sutcliffe, el error de balance de masas y la prueba t para dos muestras suponiendo varianzas iguales. Finalmente, se concluye que se pueden establecer caudales empleando el tránsito de avenidas con el método Muskingum en la cuenca La Leche, además pueden utilizarse en descargas simuladas donde se disponga de información meteorológica e hidrométrica.

Abstract: The flood routing is generally used in the analysis and evaluation of floods; however, it has been scarcely explored in the extent and determination of flows. Therefore, this research aimed to generate flows applying a simple method of flood routing known as Muskingum to monthly level, in the La Leche basin of Peru. The basin in question was chosen, since in the last 40 years it has suffered major floods, affecting a large part of the population, farmland and local infrastructure, which is why it is necessary to address its study. The methodology was of applied type and comparative non-experimental design. Due to the fact that the flood routing uses the parameters of proportionality of volume and weighting of routing in defined intervals of time, it was considered convenient to use statistical indicators to optimize the comparison of the flows registered in the hydrometric stations and the hydrographs of the simulation of a hydrological model rainfall-runoff type for different return periods, obtaining significant results in each case, according to the Pearson correlation, the Schultz criterion, the Nash-Sutcliffe criterion, the mass balance error and the t-test for two samples assuming equal variances. Finally, it is concluded that flows can be established using the flood routing with the Muskingum method in the La Leche basin, and can also be used in simulated discharges where meteorological and hydrometric information is available.

Abstract The sustainability of water use in agriculture is very important, and to achieve this, proper management of surface water resources is required, which, in small basins, depends on good measurement of flow rate data. This work analyzes the hydraulic performance of three proposed modified long-throated flumes with a 10% slope supercritical channel by using the WinFlume® v.1.06 software for a maximum flow of 50 L s-1, for clean water and in conditions in which the cross section of the inlet was modified by sediments. Hydraulic simulations were performed for triangular, rectangular, and trapezoidal cross sections in the throat and the supercritical channel by using the Iber® v.2.5.2 software to compare the pattern of the WinFlume® gauging curve with the results of Iber®; the difference between both gauging curves was a maximum error of 3% in the three cross-sectional areas. For hydraulic simulation in the supercritical modified cross-sectional area for clean flow water and sediment flow water, data located at half the total length of the supercritical channel were taken. Variations in flow depth assuming sedimentation were negligible, and it was found that the water profile in the supercritical channel was not affected, so it can be used as an indicator. In addition, it was observed that the best cross-sectional area for the channel was the rectangular one with a maximum of 0.9997 R2 for the flow rate curve (Q-h).

Resumen La sostenibilidad del uso del agua en la agricultura es muy importante, y para lograrlo se requiere de una gestión adecuada de los recursos hídricos superficiales, que en cuencas pequeñas depende de una buena medición de los datos de caudales. Este trabajo analiza el desempeño hidráulico de tres aforadores modificados de garganta larga propuestos con un canal supercrítico de pendiente de 10%, utilizando el software WinFlume® v.1.06 para un flujo máximo de 50 L s-1, para agua limpia y en condiciones en las que la sección transversal de la entrada fue modificada por sedimentos. Se realizaron simulaciones hidráulicas para secciones transversales triangulares, rectangulares y trapeciales en la garganta y el canal supercrítico, empleando el software Iber® v.2.5.2, para comparar el patrón de la curva de aforo de WinFlume® con los resultados de Iber®, la diferencia entre ambas curvas de aforo fue de un error máximo de 3% en las tres áreas transversales. Para la simulación hidráulica en el área de sección transversal modificada supercrítica para agua de flujo limpio y agua de flujo con sedimentos, se tomaron datos situados a la mitad del largo total del canal supercrítico. Las variaciones de la profundidad del flujo suponiendo sedimentación fueron insignificantes, y se encontró que el perfil del agua en el canal supercrítico no se vio afectado, por lo que puede usarse como indicador. Además, se observó que la mejor área de sección transversal para el canal fue la rectangular con un máximo de 0.9997 R2 para la curva de caudal (Q-h).

Abstract Soil moisture content can be used to predict drought impact on agricultural yield better than precipitation. Remote sensing is viable source of soil moisture data in instrument-scarce areas. However, space-based soil moisture estimates lack suitability for daily and high-resolution agricultural, hydrological, and environmental applications. This study aimed to assess the potential of the random forest machine learning technique to enhance the spatial resolution of remote soil moisture products from the SMAP satellite. Models were built using random forest for spatial downscaling of SMAP-L3-E, then visually and statistically evaluated for disaggregation quality. The impact of topography, soil properties, and precipitation on the downscaled soil moisture was examined. The relationship between downscaled soil moisture and in-situ soil moisture was analyzed. The results indicate that the proposed method demonstrated spatial and hydrological coherence, along with a satisfactory downscaling quality. Statistical validation indicated suitable generalization error for scientific and practical use (RMSE < 0.05 cm3 cm-3). Random forest effectively achieved spatial downscaling of SMAP-L3-E in the study area. Principal component and spatial analysis revealed dependence of downscaled soil moisture on elevation, soil organic carbon content, clay content, and saturated hydraulic conductivity, mainly under near-saturation conditions. Regarding validation against in-situ data, downscaled soil moisture explained in-situ soil moisture well under low soil water content (ρ = 0.624). Downscaling performance deteriorates for water contents between 0.40 to 0.50 cm3 cm-3, suggesting inadequacy under near saturation conditions at a daily temporal frequency. However, coarser temporal aggregations (7 to 10 days) yielded an average 0.98 correlation coefficient, regardless of saturation conditions. These results could potentially be applied in irrigation planning, soil physics studies and hydrology monitoring, to forecasting the occurrence of droughts, leaching of contaminants, surface runoff modeling, carbon cycle studies, soil's capacity to store and provide nutrients. Our results could mainly be applied to understanding the impact of droughts on crop yield.

Non-perennial rivers (NPRs) have three hydrological states; each state has its importance, function and implication for water resource management. The dynamics of these states have been inadequately assessed and understood. Hence, this study sought to determine the spatiotemporal variations in the hydrological :onditions of NPRs, focusing on the Touws River-Karoo drylands and Molototsi River within the semi-arid region of the Limpopo Province of South Africa. Additionally, the study aimed to delineate and characterize the primary areas contributing to runoff in these two river systems. Sentinel-1 and Sentinel-2 satellite data sources were employed in this study. Specifically, the modified normalized difference water index (MNDWI) derived from Sentinel-2 was utilized to delineate water surface areas along the two rivers. Subsequently, these derived datasets were utilized to assess the hydrological states over a 32-month period (2019-2022,. Based on the presence of water, the river's state was classified as flowing, pooled, or dry. The results showed that remote sensing can be used to determine the hydrological state of the two river systems with -90% overall accuracy. However, there is about a 30% chance that a flow event can be missed using Sentinel-2 due to clouds and temporal resolution. Some of these gaps can be filled using synthetic aperture radar (SAR) data (Sentinel-1), as demonstrated with the Molototsi River. In the Molototsi catchment, the upper catchment contributes the majority of flows. For theTouws River, the southwestern part of the catchment was determined as the major contributing area for the observed flows. This suggests that the chosen observation site might riot be representative of upper catchment dynamics; therefore, a monitoring site in the upper catchment is equired. This study provided hydrological information and an approach that can be used to monitor the hydrological states for better understanding and management of NPRs and catchments.

Event-based estimates of the design flood in ungauged catchments are normally based on a single catchment response time parameter expressed as either the time of concentration (Tc), lag time (T L) and/or time to peak (Γρ). In small, gauged catchments, a simplified convolution process between a single observed hyetograph and hydrograph is generally used to estimate these time parameters. In medium to large heterogeneous, gauged catchments, such a simplification is neither practical nor applicable, given that the variable antecedent soil noisture status resulting from previous rainfall events and spatially non-uniform rainfall hyetographs can result in multi-peaked hydrographs. In ungauged catchments, time parameters are estimated using eithei empirical or hydraulic methods. In South Africa (SA), unfortunately, the majority of the empirical methods recommended for general use were developed and verified in catchments < 0.45 km² without using any local data. This paper presents the further development and verification of the streamflow-based approach developed by Gericke (2016) to estimate observed Tp values and to derive a regional empirical Tp equation in Primary Drainage Region X, SA. A semi-automated hydrograph analysis tool was developed to extract and analyse complete hydrographs for time parameter estimation using primary streamflow data from 51 flow-gauging sites. The observed T P values were estimated using three methods: (i) duration of total net rise of a multi-peaked hydrograph, (ii) triangular-shaped direct runoff hydrograph approximations, and (iii) linear catchment response functions.The combined use of these methods incorporated the high variability of event-based time parameters, and Method (iii), in conjunction with an ensemble-event approach sampled from the time parameter distributions, should replace the event-based approaches to enable the improved calibration of empirical time parameter equations. The conceptual approach used to derive the regional empirical Tp equation should also be adopted when regional equations need to be derived at a national scale in SA.

ABSTRACT Coastal wetlands adjacent to urban areas, such as the Pantanos de Villa in the city of Lima, Peru, are subject to constant changes in land use due to anthropogenic interaction. This has led to the reduction of dense vegetation areas, giving way to built-up areas. Therefore, this article addresses the issue of the physical changes experienced in urban areas adjacent to the wetland, such as the environmental management units, in this case the Zone of Protection of Outcrop and Surface Runoff (ZPAES), and the Zone of Landscape Protection of Edge (ZPB), as well as the Pantanos de Villa Wildlife Refuge (RVSPV), as a result of rapid urban expansion. Therefore, the objective of this research is to analyze the spatial and temporal evolution of the Pantanos de Villa environment and urbanization within the Environmental Management Units ZPB, ZPAES, and RVSPV. To achieve this, the Google Earth Engine (GEE) platform was used, and satellite images from Landsat 5 TM and Sentinel 2 MSI sensors were processed. These images were worked on in the GEE interface and analyzed using spectral indices, NDVI and NDBI, through map algebra codes and pixel masking. For cartographic representation, a Geographic Information System (GIS) was used. The results show a 291.12% increase in built-up area and a 26% reduction in vegetated area over the last 35 years, for the Environmental Management Units ZPB and ZPAES, and the RVSPV. The identified reduction is directly related to unplanned expansion of urban areas and anthropogenic activities.

RESUMEN Los humedales costeros adyacentes a zonas urbanas, como los Pantanos de Villa en la ciudad de Lima, Perú, están sujetos a cambios constantes en el uso del suelo debido a la interacción antropogénica. Esto ha llevado a la reducción de áreas de vegetación densa, dando paso a zonas edificadas. Por esta razón, el presente artículo aborda la problemática de los cambios físicos experimentados en las zonas urbanas adyacentes al humedal, como las unidades de ordenamiento ambiental, en este caso la Zona de Protección de Afloramiento y Escorrentía Superficial (ZPAES y la Zona de Protección Paisajística de Borde (ZPB), así como el Refugio de Vida Silvestre Pantanos de Villa (RVSPV), como consecuencia de la rápida expansión urbana. Por ello, el objetivo de esta investigación es analizar la evolución espacial y temporal del entorno de los Pantanos de Villa y la urbanización dentro de las Unidades de Ordenamiento Ambiental ZPB, ZPAES y el RVSPV. Para ello, se utilizó la plataforma de Google Earth Engine (GEE) y se procesaron imágenes satelitales de los sensores Landsat 5 TM y Sentinel 2 MSI. Estas imágenes se trabajaron en la interfaz de GEE y se analizaron utilizando índices espectrales, NDVI y NDBI, mediante códigos de álgebra de mapas y el enmascaramiento de píxeles. Para la representación cartográfica, se empleó un Sistema de Información Geográfica (SIG). Los resultados muestran un aumento del 291.12% en la superficie edificada y una reducción del 26% en la superficie vegetal en los últimos 35 años, para las Unidades de Ordenamiento Ambiental ZPB y ZPAES, y el RVSPV. La reducción identificada se relaciona directamente con la expansión no planificada de la superficie urbana y las actividades antropogénicas.

Abstract The current level of anthropogenic impact on open water sources shows a decrease in the quality of surface runoff, a constantly growing volume of water withdrawal for economic purposes, exerting the greatest significant impact and damage on the hydrobiological resources of water sources. The processes of interaction between subjects of hydro-biocenosis force us to study the mechanisms of interaction between fish, water flow, and hydraulic structure (channel), including the optimization of elements of hydraulic structures that affect the environmental safety of a water source as a whole. We noted the main formation patterns of the structure of a turbulent flow and its interaction with a hydraulic structure (channel), such as the pulsating nature of the aquatic environment, heterogeneous structure, gradient nature, and vortex structure. We analyzed the advantages and features of the effect of three-dimensional flow-forming elements on the behavior of fish. We developed the design and method of designing a bottom flow-forming element for controlling the behavior of fish in a river flow, substantiated geometrical parameters, created an optimal layout of bottom flow-forming elements in artificial channels. We provided an assessment of the use of technical solutions for flow-forming elements of existing and reconstructed fish protection facilities. runoff purposes hydrobiocenosis hydro biocenosis channel, channel , (channel) whole environment threedimensional three dimensional flowforming forming parameters channels facilities (channel

Resumo O nível atual de impacto antropogênico em mananciais abertos indica uma diminuição na qualidade do escoamento superficial, um volume cada vez maior de captação de água para fins econômicos, exercendo o maior impacto e danos significativos sobre os recursos hidrobiológicos dos mananciais. Os processos de interação entre sujeitos da biocenose aquática nos obrigam a estudar os mecanismos de interação entre peixes, fluxo de água e estrutura hidráulica (canal), incluindo a otimização de elementos de estruturas hidráulicas que afetam a segurança ambiental de fontes de água como todo. Observamos os principais padrões de formação da estrutura de um escoamento turbulento e sua interação com uma estrutura hidráulica (canal), como a natureza pulsante do ambiente aquático, sua estrutura heterogênea, natureza gradiente e formação de vórtices. Analisamos as vantagens e características do efeito de elementos tridimensionais formadores de fluxo no comportamento dos peixes. Desenvolvemos o projeto e o método de projeto para um elemento formador de fluxo de fundo visando controlar o comportamento de peixes em um fluxo de rio, substanciamos parâmetros geométricos, criamos um layout otimizado para elementos formadores de fluxo de fundo em canais artificiais. Fornecemos uma avaliação do uso de soluções técnicas para elementos formadores de fluxo em instalações existentes e reconstruídas para a proteção de peixes. superficial econômicos canal, canal , (canal) todo aquático heterogênea vórtices rio geométricos artificiais (canal