Available Water Resources Research Articles

Evaluasi Dampak Peningkatan Populasi Terhadap Ketersediaan Air Tanah pada Perumahan CitraGrand Kota Semarang

Indonesia experiences an increase in population every year, which has an impact on the need for clean water. The increasing demand for clean water will certainly lead to the exploitation of water resources such as groundwater. Groundwater if used for a long period of time can potentially have a negative impact on both the environment and all living things and can affect the availability of water resources. One of the housing estates that still uses groundwater to meet the main needs of clean water is CitraGrand housing located on Jalan Kompol R. Soekanto, Tembalang District, Semarang City. This research was conducted in the CitraGrand residential area of Semarang City because this housing still uses groundwater along with the increasing population, so this research aims to analyze the distribution range and the amount of groundwater availability. Furthermore, the final results show that in 2033 the groundwater availability capacity in CitraGrand Semarang residential area has reached -3,936.9 million m3. This may indicate that the availability of groundwater can no longer be utilized as the main need for clean water. Therefore, the analysis results of this study can be used as a reference for developers related to strategies in sustainable water resources management.

Analyzing river disruption factors and ecological flow in China's Liu River Basin amid environmental changes.

Water resources variability and availability in a basin affect river flows and sustain river ecosystems. Climate change and human activities disrupt runoff sequences, causing water environmental issues like river channel interruptions. Therefore, determining ecological flow in changing environments is challenging in hydrological research. Based on an analysis of long-term changes in hydrological and meteorological variables and interruption conditions in the semi-arid Liu River Basin (LRB), this study summarizes the controlling factors of river interruption at different temporal and spatial scales and proposes a framework to determine ecological flow under changing environments. Hydrological model and the monthly optimal probability distribution were used to determine the optimal ecological runoff of LRB. The results showed that from 1956 to 2017, precipitation and potential evapotranspiration in the basin showed no significant decreasing trend, but the streamflow significantly decreased, and the downstream interruption worsened, with an average annual interruption duration of 194days at Xinmin Station from 1988 to 2017. The controlling factors of river interruption are as follows: (1) soil and water conservation measures in the upstream significantly reduce the runoff capacity; (2) the operation mode of the controlling reservoir in the middle reaches changes from "all-year discharge" to "winter storage and spring release" to "combined storage and supply," severing the hydraulic connection between upstream and downstream; and (3) siltation in the downstream river channel coupled with over-extraction of groundwater increases the seepage capacity of the river. The monthly ecological flow of Naodehai Reservoir was determined by considering the monthly seepage losses after reconstructing the natural runoff using the SWAT model and determining the optimal probability distribution function for monthly runoff. The findings are important for downstream LRB ecological restoration and for determining the ecological flow of other river basins in changing environments.

Hydrological dynamics and water resource availability in the Rift Valley Lakes Basin (Ethiopia), using a WEAP model

Abstract This study aims to assess hydrologic dynamics and the water resource potential of the Rift Valley Lake Basin (RVLB) in Ethiopia using the Water Evaluation and Planning System (WEAP) model. The surface water of the RVLB comprises streamflow and an open water system. The model was configured with 13 catchments and a monthly time series of approximately 43 years (1981–2022) to address the spatial variability of rainfall-runoff interaction. Statistical performance indicators were used to evaluate the accuracy of the model in simulating streamflows, and the results showed that the coefficient of determination (R2) ranges from 0.82–0.93, Nash-Sutcliffe coefficient of efficiency (NSE) ranges from 0.68–0.86, percentage of bias (PBIAS) ranges from –9.45 to –1.85, standard deviation ratio (RSR) ranges from 0.35 to 0.59 and index of agreement (IA) ranges from 0.62 to 0.84. The available surface water for abstraction is estimated to be 358 million cubic meters (MCM) available as lake water abstraction, and 6,534 MCM as streamflow water, making it a total surface water flow of 6,892 MCM. Considering the temporal distribution of the surface water sources, 67.5% is available in the rainy season, June–October, and 32.5% during the dry period, November–May, in the basin.

A new approach for upgrading Biogas produced at a local wastewater treatment plant

<p>Biogas is globally recognized as a crucial source of renewable energy. After undergoing proper treatment, the purified form of biogas, known as "biomethane", has the potential to be injected into existing natural gas infrastructure or compressed for use as a vehicle fuel. The principal pollutants which cause a reduction in the energy density of biogas and impede its utilization, specifically in engines, are carbon dioxide, hydrogen sulfide, and siloxanes. Furthermore, the presence of carbon dioxide in biogas has a significant impact on global warming. In this study, the water scrubbing method, which is the most used method in biogas upgrading processes, was utilized due to its low operating cost. With the decreasing availability of clean water resources around the world and the challenges of utilizing them, the reuse of treated wastewater has become increasingly important. Therefore, in this study, treated wastewater was used as scrubbing water for biogas instead of clean water. In addition, the biogas used in the study is the gas produced in the wastewater treatment plant of a local municipality, thus contributing to the uniqueness of the study. Prior to upgrading, the biogas content produced in the plant had CH4 and CO2 values of 62% and 37%, respectively. However, after the implementation of upgraded technology, these values increased to 96% (CH4) and 3% (CO2). These results clearly demonstrate the success of the new method.</p>

Assessing the impact of missing data on water quality index estimation: a machine learning approach

Despite the regulations and controls implemented worldwide by governments and institutions to ensure the availability and quality of water resources, many water sources remain susceptible to contamination. This contamination poses significant risks to human health and can lead to substantial economic losses. One of the challenges in this context is the presence of missing or incomplete data, which can arise from various factors such as the methodology used or the expertise of personnel involved in sample collection and analysis. The existence of such data gaps hampers the accurate analysis that can be conducted. To address this issue and estimate a water quality index from the available samples, it is crucial to handle missing information appropriately to avoid biased calculations. This study focuses on the application of machine learning methods for imputing missing data in water samples. Furthermore, it quantifies the performance of different models based on the distribution of the obtained data. By applying 10 distinct methods to a sample of water quality data, the most effective approaches, namely Bayesian Ridge, Gradient Boosting, Ridge, Support Vector Machine, and Theil-Sen regressors, were identified. The selection of these models was based on the evaluation of two estimation error metrics: average percent bias (PBIAS) and Kling-Gupta Efficiency statistic (KGEss). The respective metric values for the aforementioned methods are as follows: ⟨PBIAS⟩0.5=14.665,19.555,14.300,15.380,15.920\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\langle \\hbox {PBIAS}\\rangle _{0.5}=14.665, 19.555, 14.300, 15.380, 15.920$$\\end{document} and ⟨KGEss⟩0.5=0.670,0.585,0.655,0.620,0.595\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\langle \\hbox {KGEss}\\rangle _{0.5}=0.670, 0.585, 0.655, 0.620, 0.595$$\\end{document}. The results obtained from these models have been utilized to establish unbiased relationships among physical, chemical, and biological parameters based on the information retrieved through the applied imputation methods.

Water resources availability in the Mefou basin, Cameroon: under current and future climate, and land use and land cover

Water resources availability in the Mefou basin, Cameroon: under current and future climate, and land use and land cover

EVALUATION OF VEGETATION COVER DYNAMICS IN A SUB-TROPICAL CLIMATE USING HIGH-RESOLUTION MULTISPECTRAL DATA FROM UAVS

The study of vegetation status is of great importance as it reveals environmental factors and their relationship with the availability of water resources, components that are relevant in the planning, drafting and execution of numerous civil engineering projects. Detecting changes in vegetation cover often requires data from space-based platforms, which may have limitations in terms of spatial or temporal resolution and high costs for acquiring high-resolution data. For relatively small areas, the use of Unmanned Aerial Vehicles (UAVs) provides a solution. These devices facilitate the acquisition of land cover information with high spatial and temporal resolution through the use of photographic cameras or specialized sensors. This research analyzes the vegetation status within a study area characterized by distinct climatic seasons (dry and humid) within a warm sub-tropical climate. The primary focus lies in detecting changes in vegetation cover and evaluating the overall state of the vegetation. To accomplish this objective, a multirotor UAV equipped with a multispectral camera that captures RED and NIR bands is deployed. Various vegetation indices based on distance and slope are applied to access the vegetation’s condition. The analysis of the results indicates that it is possible to evaluate the vegetation cover dynamics using the very high-resolution data obtained with the VANT approach (10 cm per pixel). Notably, the distance-based vegetation indices demonstrate superior efficacy in delineating the vegetation status and the stress induced by the scarcity of water resources during the transition between dry and humid seasons.

Changing agricultural practices as a result of variable water resource availability in a hilly area of An Giang province, Vietnam

Abstract Located in the Southwest of the Mekong Delta in Vietnam, An Giang province is an important center of agricultural production, especially rice cultivation. Climate change impacts are one of several man-made factors affecting water resource availability for agriculture in the province. It is recognized that new solutions are crucial to adapt to the present and future conditions of a scarcer water supply. This paper explores climate factors affecting water resource availability in agriculture and some recent adaptations being adopted by farmers in one district of An Giang province. Hydro-meteorological data was collected together with in-depth interviews as a tool to point to proximate changes in water status and availability and to evaluate local inhabitants’ awareness of climate risks and adaptive strategies. The results noted that climate factors (temperature, humidity, annual rainfall) have altered over time, causing decreased availability of water supplies for agriculture. Recognizing this situation, both structural adaptation and non-structural solutions may occur simultaneously to maintain agricultural production efficiency. The types of crops, tolerant varieties, and irrigation projects suitable for various geographical areas were considered for more adaptive agriculture production locally. To address some of the problems that farmers face, water-saving technologies are an essential part of a range of potential solutions to maintain agricultural production and protect the environment in the future.

Variable drivers trigger future change in water yield capacity of terrestrial ecosystems in Africa: An intensification of reduction and unevenness

Predicting the water-related services of terrestrial ecosystems in a changing climate is of great significance for managing rich ecosystems in water-scarce areas. Water yield capacity (WYC), which characterizes water resource availability, was thrown into sharp focus of this study. The spatiotemporal trends of WYC and their dynamics by potential climate shifts were evaluated based on calculative WYC and climate zones for historical period (2001–2018) and future scenarios (both 2050 and 2100 under SSP1-2.6 or SSP5-8.5 scenarios). The multiple factors affecting WYC in the recent past were identified as the basis for explaining the future tendency in WYC. All analyses were conducted from the perspective of holistic continental scale and specific basin scale so as to explore the contrast between various scales. The results showed that the total WYC both in whole Africa and the four major basins (the Congo, the Nile, the Niger and the Zambezi) are projected to decrease in 2050 and 2100 compared with that in 2018, under both SSP1-2.6 or SSP5-8.5 scenarios describing future pathways with low or high greenhouse gas emissions, respectively. The areas producing WYC will be more concentrated, suggesting that the proportion of areas contributing to the top 50% of this function across Africa will drop from current 10.5% to 4.94% in 2100 under SSP5-8.5 scenario. As climate zones are likely to shift in the future, the WYC will reduce most in the areas experiencing the conversion between tropical monsoon and tropical rainforest climates. In addition, WYC was driven by precipitation, temperature, net primary productivity (NPP) and landscape pattern (connectivity and diversity), which had spatial scale effect. The results add evidence for unstable availability of water resources provided by terrestrial ecosystems in a multi-scale manner.

Multicriteria Decision Making in Site Selection for Nuclear Power Plants

Nuclear energy is an important alternative energy source. However, construction of nuclear power plants (NPPs) requires the consideration of environmental, economic, socioeconomic, health, and safety factors since using such an energy source involves some risks during the operation lifetime of a NPP. Accordingly, the selection of the most suitable site for a NPP yields a multicriteria decision making (MCDM) problem. Natural hazards, health hazards, environmental conditions, population density, and the availability of water resources are among the main factors that should be considered. To demonstrate the application of the proposed methodology, two previously identified NPP sites in Turkey, specifically, Mersin-Akkuyu and Sinop-Abalı, are compared utilizing the multicriteria utility functions. In the comparison of these two sites, seismic hazard, tsunami hazard; extreme wind hazard; distance to facilities; population density; proximity to the city center; existence of forests, natural parks, nature conservation areas, and natural monuments; biodiversity; and immovable cultural heritage have been identified as the most important critical criteria and are evaluated concerning the utility functions developed for each criterion. The optimal site is selected within the framework of the MCDM rules, and is recommended as the output of the study.

Aquifers and Groundwater: Challenges and Opportunities in Water Resource Management in Colombia

Water is essential for life on Earth, playing fundamental roles in climate regulation, ecosystem maintenance, and domestic, agricultural, and industrial processes. A total of 70% of the planet is covered by water. However, only 2.5% is fresh water, and much of it is inaccessible. Groundwater is the main source of the planet’s available water resources. For that reason, groundwater is a critically important resource, and is increasingly vulnerable due to the climate crisis and contamination. These challenges threaten the availability of clean and safe water, necessitating an understanding of effective and sustainable management. This review presents an overview of the concepts of aquifers and groundwater. Also, it reflects on the importance of these resources in developing countries such as Colombia (South America). In addition, it considers the characteristics of mineral waters, their uses, and associated risks, as well as their exploration and control policies. Colombia is a country with immense water and biological wealth and is crucial to maintaining the climate and availability of global water resources. Nevertheless, managing Colombia’s aquifers is a challenge, as many have not yet been fully explored. In order to achieve this, it is necessary to study hydrogeochemistry through the application of advanced technologies to analyze the dynamics, distribution, and quality of groundwater, as well as its vulnerability to pollution and climate change. On the other hand, the consumption of mineral groundwater can have health benefits, such as positive cardiovascular and gastrointestinal effects. But geogenic, biogenic, or anthropogenic elements such as heavy metals and microplastics can pose a risk to human health. The need for proper management of water resources to prevent risks to human health and the environment is emphasized. Therefore, an integrated approach to water resource management will ensure conservation and sustainable use, secure a continuous supply of freshwater, and facilitate adaptation to climate change.

Availability of the current and future water resources in Equatorial Central Africa: case of the Nyong forest catchment in Cameroon.

To anticipate disasters (drought, floods, etc.) caused by environmental forcing and reduce their impacts on its fragile economy, sub-Saharan Africa needs a good knowledge of the availability of current water resources and reliable hydroclimatic forecasts. This study has an objective to quantify the availability of water resources in the Nyong basin and predict its future evolution (2024-2050). For this, the SWAT (Soil and Water Assessment Tool) model was used. The performance of this model is satisfactory in calibration (2001-2005) and validation (2006-2010), with R2, NSE, and KGE greater than 0.64. Biases of - 11.8% and - 13.9% in calibration and validation also attest to this good performance. In the investigated basin, infiltration (GW_RCH), evapotranspiration (ETP), surface runoff (SURQ), and water yield (WYLD) are greater in the East, probably due to more abundant rainfall in this part. The flows and sediment load (SED) are greater in the middle zone and in the Southwest of the basin, certainly because of the flat topography of this part, which corresponds to the valley floor. Two climate models (CCCma and REMO) predict a decline in water resources in this basin, and two others (HIRHAM5 and RCA4) are the opposite. However, based on a statistical study carried out over the historical period (2001-2005), the CCCma model seems the most reliable. It forecasts a drop in precipitation and runoff, which do not exceed - 19% and - 18%, respectively, whatever the emission scenario (RCP4.5 or RCP8.5). Climate variability (CV) is the only forcing whose impact is visible in the dynamics of current and future flows, due to the modest current (increase of + 102 km2 in builds and roads) and future (increase of + 114 km2 in builds and roads) changes observed in the evolution of land use and land cover (LULC). The results of this study could contribute to improving water resource management in the basin studied and the region.

Research on Key Technologies for Optimization of Water Systems and Efficient Utilization of Regenerated Water in Thermal Power Plants

Water is the source of life, an essential element in production, and the foundation of ecosystems. In the natural hydrological cycle, water that can be utilized by humans is referred to as water resources. Water resources form the basis for human survival and development, intimately connected to daily life, and concurrently represent a controlling factor in the ecological environment. It is well-known that the thermal power generation industry has consistently been a major consumer of water in the industrial sector, with substantial demands for water resources. Throughout the process of thermal power generation, water resources are extensively utilized for cooling, steam generation, waste heat discharge, and other processes. This large-scale utilization of water resources not only imposes pressure on local water resources but also leads to pollution of water environments and disruption of ecosystems.To address the challenges posed by the limited availability of water resources and environmental pollution, this paper explores the key technologies for optimizing water systems in thermal power plants. Through in-depth analyses of 3S water source optimization technology, ABFT biological treatment processes, recycled water utilization technology in the circulating cooling system, reclaimed water reuse technology, and the coal-fired "flue gas desulfurization" process, coupled with empirical studies of typical cases, the aim is to propose viable optimization solutions for water systems.

Between Anthropogenic Influence and Resource Management: Impacts of Risks and Preservation Strategies in the Ikopa Watershed, Madagascar

The impacts of anthropogenic risks on water resource management underscore the necessity for a careful and adaptable approach to ensure long-term sustainability. In the Ikopa Watershed in Madagascar, numerous human activities present significant challenges. Water quality is impacted by pollution resulting from agricultural practices. Uncontrolled deforestation intensifies watershed degradation, jeopardizing the availability of water resources. Rapid urbanization and escalating human activities further contribute to the deterioration of water quality. The hypothesis posits that responsible exploitation of natural resources contributes to the preservation and sustainability of water resources in the Ikopa Watershed. This study concentrates on investigating potential anthropogenic risks that influence resource degradation and the perception of mitigation measures. The main objective of this section is to assess the anthropogenic risk factors contributing to water resource degradation in the watershed. The study employs change detection studies through remote sensing and GIS approaches, complemented by social analysis. This methodology aims to identify potential anthropogenic risks affecting responsible water resource management, along with an exploration of local mitigation strategies. The results underscored potential risks faced by the local population in the watershed, including challenges associated with agriculture, urbanization, inadequate drainage network management, and high population density. Binary logistic regression analysis reveals significant connections between anthropogenic risks and the mitigation strategies adopted by local communities in the Ikopa Watershed. The findings indicate that specific characteristics of degradation or local interventions can either positively or negatively influence the adoption of these strategies.

Tata kelola sumber daya air berkelanjutan-berkeadilan : Bagaimana Indonesia memperkuat poros maritim?

Water resources are an important aspect of human survival. However, population growth, urbanization, climate change, agricultural expansion, and industrialization have led to a rapid decline in the quality and availability of water resources. It is estimated that by 2050, the global population will reach 9.7 billion, which will increase the need for water resources. Currently, approximately 2.3 billion people live in water-critical areas, and two-thirds of the global population experiences critical water shortages for at least one month of the year. The United Nations has established Sustainable Development Goals, with a focus on clean water and sanitation. Indonesia, with more than 17,000 islands, has rich water resources but is vulnerable due to urbanization, pollution, and climate change. To overcome these challenges, sustainable water governance is necessary. Indonesia is already experiencing water shortages, and it is estimated that 67% of economic activity will be in areas experiencing water scarcity by 2045. In addition, Indonesia is among the ten largest groundwater-consuming countries, drawing groundwater mainly for domestic use. To overcome this challenge, the government has implemented water governance reforms through regulatory policies and infrastructure improvements. In this context, this research aims to provide an overview of the progress of sustainable water governance in Indonesia and strategies for facing challenges as a maritime axis in sustainable water governance. This study uses a systematic literature review methodology to analyze 69 articles on current water governance practices, sustainable water governance challenges, and strategies for overcoming these challenges. By adopting sustainable water governance, Indonesia can ensure fair and equitable access to water, reduce water-related conflicts, increase access to clean water and sanitation, and strengthen the country's overall environmental and economic resilience.

Water Resources Conservation in Bali: A Non-cooperative Game Theory Approach

Entering the 21st century, the world faces a global water crisis threat, due to increasing competition for freshwater which is an implication of economic growth, population growth, and climate change. Therefore, institutions that can secure the availability of water resources sustainably are urgently needed. In contrast to the tendency of research in the last two decades, which was dominated by experimental methods, this research studies local institutions in Bali called Subak using game theory as a reasoning method. Water management was analyzed using three economic frameworks namely, institutions, transaction costs, and contracts, to reveal how water institutions in Bali are managed. This study found that there are strong social norms that can maintain trust, act as a coordinating medium, eliminate transaction costs, and enforce contracts. Furthermore, the study also discusses the failure possibility of the current government intervention system because the capitalist production function alienates the value of water from its production system. Empirical research through experiments is very important, however, economics has a set of theories that can be used to predict or develop incentive mechanisms within an institution. The social norms that were found in this study can be used as a basis for the design of clean water management institutions at the village or community level with public participation.

Future potable water supply demand projection under climate change and socioeconomic scenarios: A case of Gshba subbasin, Northern Ethiopia

This paper aims to quantify the subbasin’s potable water supply demand forecast from 2023 to 2050 under various scenarios of climate change and socioeconomic development. The variability of the climate and the resulting problems with urbanization threaten the availability of water resources, especially in less developed countries like Ethiopia. Thus, the main objective of this study is showing the necessary to determine the amount of water needed in advance, in order to comply with the availability of water resources within a specified future period under different scenarios. Our indicator-based approach used a multicriteria decision-making technique. Accordingly, several important variables were considered, including climatological, anthropological, demographic, socioeconomic, and economic variables, in addition to water engineering-related factors (e.g. Water losses). The method also considered a number of factors, such as unexpected and extreme temperature changes, and forecasting factors studied by the Ethiopian Ministry of Water and Energy. The projected population in the subbasin is estimated at 2.52 million, so the total projected water supply demand i.e., for domestic, non-domestic, industrial, commercial, public, and institutional is approximately 126.53 MCM/yr by 2050. Our results revealed how changes in both climatic and socioeconomic factors strongly influence future water resource system performance, and this will help the water services provider better prioritize the refurbishment of existing infrastructure and investment in new infrastructure, and more importantly, manage the subbasin effectively by introducing resilient adaptation options.

A wise irrigation to contribute to integrated water resource management

Irrigated agriculture accounts for about 20% of cultivated lands worldwide while currently generating an estimated 40% of crop production, and two-thirds of future gains in crop production are expected to come from irrigated lands. Therefore, irrigation is strategic to ensure food for the world’s increasing population and slow down the pace of deforestation. Irrigated agriculture also accounts for more than 70% of global water withdrawals, and the way agriculture uses freshwater is crucial for ensuring availability for other activities and preserving water-related ecosystems. To give an agri-environmental interpretation of the water fluxes involved in irrigation, the total amount of water withdrawn from a source is called white water (W) and subdivided as follows: gold water (G) is the amount that is actually used by the crops. This fraction represents the ultimate goal of irrigation, which is to increase crop productivity and food availability. We can also consider this amount as the irrigation water for crops. The gold color means an income for the farm; emerald water (E) is the amount of water withdrawn for irrigation that does not reach the crops but provides ecosystem services, i.e., the benefits that people get from ecosystems. This amount of water is useful for the community and can be identified as irrigation of the territory; red water (R) is losses, i.e., the fraction of water that has to be reduced as much as possible if not eliminated. It is an economic, social and environmental cost; the red color is associated with the red traffic light that means STOP! The quantification of W has to be preceded by a careful evaluation of the benefits achievable with irrigation in relation to the environmental characteristics of the cultivation area. Strategic issues at this stage are the choice between full or deficit irrigation and the individuation of opportunities to exploration of opportunities to increase the availability of water resources by using non-conventional sources. The quantification of G and E fluxes is necessary to reduce losses, while strategies/techniques useful to reduce irrigation needs at the field level are key factors to allocate irrigation water within the framework of an integrated and sustainable management of water aimed at turning user conflicts into synergies. This implies multiple subjects and actors in a multi-disciplinary approach.

Assessing Future Precipitation Patterns, Extremes and Variability in Major Nile Basin Cities: An Ensemble Approach with CORDEX CORE Regional Climate Models

Understanding long-term variations in precipitation is crucial for identifying the effects of climate change and addressing hydrological and water management issues. This study examined the trends of the mean and four extreme precipitation indices, which are the max 1-day precipitation amount, the max 5-day precipitation amount, the consecutive wet days, and the consecutive dry days, for historical observations (1971–2000) and two future periods (2041–2060/2081–2100) under RCP2.6 and RCP8.5 emission scenarios over the Nile River Basin (NRB) at 11 major stations. Firstly, the empirical quantile mapping procedure significantly improved the performance of all RCMs, particularly those with lower performance, decreasing inter-model variability and enhanced seasonal precipitation variability. The Mann–Kendall test was used to detect the trends in climate extreme indices. This study reveals that precipitation changes vary across stations, scenarios, and time periods. Addis Ababa and Kigali anticipated a significant increase in precipitation across all periods and scenarios, ranging between 8–15% and 13–27%, respectively, while Cairo and Kinshasa exhibited a significant decrease in precipitation at around 90% and 38%, respectively. Wet (dry) spells were expected to significantly decrease (increase) over most parts of the NRB, especially during the second period (2081–2100). Thereby, the increase (decrease) in dry (wet) spells could have a direct impact on water resource availability in the NRB. This study also highlights that increased greenhouse gas emissions have a greater impact on precipitation patterns. This study’s findings might be useful to decision makers as they create NRB-wide mitigation and adaptation strategies to deal with the effects of climate change.

Thermodynamic and hydrological drivers of the soil and bedrock thermal regimes in central Spain

Abstract. An assessment of the soil and bedrock thermal structure of the Sierra de Guadarrama, in central Spain, is provided using subsurface and ground surface temperature data coming from four deep (20 m) monitoring profiles belonging to the Guadarrama Monitoring Network (GuMNet) and two shallow profiles (1 m) from the Spanish Meteorology Service (Agencia Estatal de Meteorología, AEMET) covering the time spans of 2015–2021 and 1989–2018, respectively. An evaluation of air and ground surface temperature coupling showed that soil insulation due to snow cover is the main source of seasonal decoupling, being especially relevant in winter at high-altitude sites. Temperature propagation in the subsurface was characterized by assuming a heat conductive regime by considering apparent thermal diffusivity values derived from the amplitude attenuation and phase shift of the annual cycle with depth. This methodology was further extended to consider the attenuation of all harmonics in the spectral domain, which allowed for analysis of thermal diffusivity from high-frequency changes in the soil near the surface at short timescales. For the deep profiles, the apparent thermal diffusivity ranges from 1 to 1.3×10-6 m2 s−1, which is consistent with values for gneiss and granite, the major bedrock components in the Sierra de Guadarrama. However, thermal diffusivity is lower and more heterogeneous in the soil layers close to the surface (0.4–0.8×10-6 m2 s−1). An increase in diffusivity with depth was observed that was generally larger in the soil–bedrock transition at 4–8 m depth. The outcomes are relevant for the understanding of soil thermodynamics in relation to other soil properties. Results with the spectral method suggest that changes in near-surface thermal diffusivity are related to changes in soil moisture content, which makes it a potential tool to gain information about soil drought and water resource availability from soil temperature data.