Cuadernos de Investigación Geográfica

Water Planning and Management in Spain in a Climate Change Context

2024-12-20T12:19:32+01:00

Water planning and management in Spain is being affected by the recorded effects of the current climate change process. The traditional paradigm based on a policy of continuous water supply no longer fits with the forecasts of decreasing water flows identified by climate and hydrological modelling. The guarantee of water security, a guiding principle of planning, as indicated by Spanish Climate Change Law (2021), requires the incorporation of new water resources that allow water management to be less dependent on rainfall. Effective demand management, the incorporation of regenerated water with a high level of purification, the inclusion of rainwater for urban and leisure uses and the use of desalinated water in coastal areas to be used mainly for urban water supply are presented as viable alternatives to the development of large public hydraulic works that prove ineffective in drought conditions. This paper presents an updated balance of water resources and demands and analyses the increasing difficulty of hydrological planning in our country within a complex political context that requires cooperation and governance actions in water matters. A series of recommendations are proposed, from a geographical perspective, for the necessary adaptation of hydrological planning to the effects of climate change in Spain.

The influence of climate variability on risk assessment of tropical cyclogenesis in the Gulf of Mexico

2024-12-20T12:19:52+01:00

Climate change and climate variability risk assessments are usually focus on tropical cyclones due to the potential hazard for human society, especially in urban coastal areas such as those along the Gulf of México. The frequency of this natural phenomenon depends on the confluence of different dynamic (wind divergence and relative vorticity) and thermodynamic (atmospheric water content and sea surface temperature) factors. Large scale atmospheric oscillations modulate these factors and influence tropical cyclone (TC) formation and development, producing important social and economic impacts. This work explores the Maden-Julian Oscillation (MJO) and El Niño-South ern Oscillation (ENSO) relationship in regard to the Gulf of México tropical cyclogenesis, using time series and synoptic case study analyses, in order to contribute to future risk assessments in these coastal zones. Results indicate MJO and ENSO frequencies are present in wind divergence and relative vorticity, atmospheric water vapor content, and sea surface temperature. Concurring cold phase ENSO and convective phase MJO conditions benefit TC formation, while warm phase ENSO conditions inhibit TC formation and affect the MJO cycle. Synoptic case study analyses show wind divergence and atmospheric water content anomalies dominate TC behavior.

Changes in the Climate Comfort of the Coast of Spain (1940-2022)

2024-12-20T12:19:47+01:00

The Spanish coastal regions register specific climatic conditions due to the combination of mild temperatures with little variation throughout the year, high relative humidity and the influence of maritime storms. In summer, the climatic comfort conditions are excessively hot, especially on the Mediterranean coast of Spain. Understanding these conditions and analysing the temporal evolution of recent decades, as well as regional differences, is fundamental for future summer tourism planning in the coming decades. This study analyses the principal 37 coastal tourist hubs of Spain grouped into 10 large regions (the Atlantic, Cantabrian, Mediterranean coasts, and the two archipelagos of the Balearic and Canary Islands). Daily data drawn from the ERA-5 (Copernicus) atmospheric reanalysis from 1940 to 2022 have been used (mean air temperature, mean relative humidity, and mean wind speed), with which the Climate Comfort Index has been calculated (CCI) by González (1998). The results show a significant reduction of the CCI in all the coastal areas analyzed, being more relevant in winter (-0.10 decade). The decrease in the index implies a decrease in cold thresholds and an expansion of comfort throughout the study area, especially in the central Mediterranean and Cantabrian Sea. For its part, in summer, the most important decreases (-0.07 and -0.08 / decade) show an increase in the most important climatic discomfort on the Cantabrian Coast – Euskal Kostaldea and on the Costa Brava-El Garraf, with a significant intensification and expansion temporary thermal sensation of heat. In other coastal sectors, in recent years, the climatic thresholds of heat and extreme heat have been reached for the first time.

How does climatic variability affect the Highland Lagoons of the venezuelan Andes?

2024-12-20T12:19:36+01:00

The influence of climate variability in the highland headwater lagoons of the Miguaguó watershed - Venezuela was evaluated from an initially defined time series of 46 years, climatologically classified by the Oceanic Niño Index (ONI). 18 climatologically different sample years were selected with the availability of Landsat imagery to evaluate the degree of surface water extent fluctuation using the Normalized Water Index (NDWI). The NDWI values were then statistically compared with the ONI and with local climate parameters, and the percentage deviations of the anomalies from the averaged neutral years were estimated. The results showed that the surface water extent of the lagoons is affected by the combination of ENSO, anti-ENSO anomalies and neutral years, although the effect is different depending on the location of the lagoons in the landscape, biophysical conditions and the intensity of the anomalies. Mapire, La Burra and Masiegal lagoons showed “severe” impact, with deviations from the surface water extent in neutral years ranging from 20 to 70%. On the other hand, the impact on the Miguaguo lagoon was mostly “slight”, with deviations ranging from 0 to 10%. Positive deviations derived from anti-ENSO events and neutral conditions were generally dominant, except for La Burra lagoon, where the opposite trend was observed. Although the results were clear and conclusive, they have a limited spatial and temporal scope due to the complexity of the processes involved. Therefore, additional research is needed to complete the understanding of the climatic and atmospheric relationships in the processes governing the highlands of the tropics.

Analysis of Flood Risk in the Lower Hydrographic Basin of the Río Negro (Argentina)

2024-12-20T12:19:45+01:00

The recurrent floods in the lower hydrographic basin of the Río Negro (RN), documented since 1899, have caused significant damage to the resident population settled in flood-prone areas, whose socioeconomic condition is unfavorable. The aim of this study was to analyze the risk associated with flood occurrences in this area by integrating the flood susceptibility level (hazard) of the study area and the vulnerability of the population. The risk analysis was derived from the algebraic overlay of hazard and vulnerability maps, developed according to criteria published by Renda et al. (2017). In the study area, floods are primarily caused by intense rainfall and winds, upstream water discharges from the Limay and Neuquén rivers, and interactions between increased upstream flow from the lower hydrographic basin of the RN and extreme meteorological events known as Sudestadas. Every certain period, such as every 2 years for winds exceeding 75 km/h and precipitation exceeding 37 mm in 24 hours, as well as every 100 years for flows exceeding 4,000 , the occurrence of floods in the lower basin of the RN is expected to be derived from these events. Based on terrain characteristics and topography, 41.7% of the lower RN basin area showed moderate to high susceptibility to flooding. INDEC data (2010) indicated that 51.0% of the population in the study area was vulnerable to floods due to unfavorable socioeconomic conditions. According to hazard and vulnerability analyses, 43.2% of residents in the lower RN basin lived in high-risk areas, with homes located near the riverbank and on the outskirts of the Viedma-Carmen de Patagones urban conglomerate, hence being the most vulnerable. The results obtained in this research showed the influence of the natural and anthropogenic factors on the occurrence of flood-related disasters in the lower hydrographic basin of the RN. In addition, they served as a preliminary study that will enable decision-makers to create better prevention and mitigation plans contributing to improving the quality of life of its inhabitants.

Study of land uses in the Sorocabuçu River watershed, Ibiúna-SP, (Brazil) for the evaluation of eligible areas in MDL projects

2024-12-20T12:19:49+01:00

The constant population growth along with the demand for natural resources put pressure on forests' capacity to capture CO₂, among other benefits, thus arising the need to implement monitoring and conservation measures. Considering the above, the objective of this study was to identify degraded areas eligible for the development of CDM projects in the Sorocabuçu River watershed, Brazil. To achieve this, land use was classified for the years 2000 and 2020 using Multi-layer Perceptron neural networks, which were evaluated using a confusion matrix and Kappa index. These classifications allowed the determination of transition potential using the LCM tool, which, along with NDVI calculation, enabled the identification of areas eligible for CDM project implementation through a Fuzzy system. In the land use classification, a loss of natural vegetation areas was identified, while the NDVI indicated the absence of areas with vegetation in the extremely healthy category. As for transition potential, it was determined that the study area mostly exhibits low potential; however, there are areas with high potential. Finally, it was found that the study area comprises 1.38% degraded areas with high eligibility for CDM project implementation.

An Integrated Methodological Approach for the Balance Between Conservation and Traditional Use in a Protected Area

2024-12-20T12:19:40+01:00

Protected Natural Areas often impose restrictions that require a delicate balance between conservation and the traditional uses upheld by local communities. This study presents a novel integrated methodological approach using anthropo-natural landscapes as the primary unit of analysis. The methodology evaluates natural suitability for various appropriate uses within the protected area, considering legal compatibility, environmental sustainability, socioeconomic benefits, and technical-financial feasibility. Our case study of the Pico Azul – La Escalera Environmental Protection Zone reveals that 59.2% of the territory is primarily suited for conservation activities, 38.3% for the rehabilitation of degraded areas, and only 2.5% for extensive livestock farming and rainfed agriculture. Additionally, 24% of the area, comprising mainly non-degraded sectors, is designed for the sustainable use of non-timber forest resources. Furthermore, alternative tourism is identified as a viable secondary use in 10.2% of the most preserved landscapes. This research underscores the importance of a comprehensive and balanced approach to managing protected areas, ensuring both conservation goals and the livelihoods of local communities are met.

Remote sensing of illegal dumps through supervised classification of satellite images: application in Oaxaca, Mexico

2024-12-20T12:19:43+01:00

Various economic, social, and cultural factors have contributed to the proliferation of illegal dumps, causing urban image degradation, population health impacts, and soil, air, and water contamination. Scientists developed remote sensing techniques to identify these red spots and thus contribute to their mitigation and control. They recently used these techniques to detect large areas of illegal waste dumping instead of using expensive field monitoring. Artificial intelligence algorithms have been used to process satellite images due to the availability of satellite images and the increase in the processing capacity of computer systems. This work presents the results of a satellite remote-sensing procedure to detect illegal dumps in one hydrographic subbasin in Oaxaca, Mexico, through a supervised land cover classification using a Random Forest classifier. Two hundred and fifty-six control polygons were used to train the classifier. The classification criteria were the twelve bands of the Sentinel 2A satellite images with a spatial resolution of 10x10 meters, the spectral indices NDVI, MNDWI, SAVI, NDBI, BSI, and the surface slope. Google Earth Engine platform was used to process satellite images. There were 288,100 hectares classified in this way: 65.4% classified as vegetation, 31.5% like bare soil, 2.7% was urban soil and the rest was classified as water or garbage. A confusion matrix calculated the accuracy of the model in 0.9517. The model was not able to accurately distinguish between urban soil, bare soil and garbage due to the similarity of their spectral fingerprints. NDVI and SAVI were the most important spectral indices for detecting litter, and those might contribute to building a spectral fingerprint of litter in the future. Poorly classified areas were discarded through photointerpretation work and post-processing. Finally, thirty-two probable illegal dumps were identified, twelve of which were confirmed on the territory.

Grazing in the Mediterranean Mid-Mountains to Mitigate Climate Change

2024-12-20T12:19:34+01:00

The livestock sector, especially in its intensive form, is considered highly relevant in the context of climate change due to its contribution to greenhouse gas emissions. However, livestock production is necessary to feed the population and to conserve ecosystems services and cultural landscapes. On the other hand, extensive livestock farming can help to mitigate climate change through grazing. This study analyses how the combination of shrub clearing and grazing contributes to reducing forest fires and increasing organic carbon (SOC) storage in the soil. The study was conducted in the Northwestern Iberian System (Spain), a sparsely populated Mediterranean mid-mountain region. In the landscape predominates shrubs in different stages of plant succession after rural abandonment, with extensive livestock farming being the main economic activity. Since 1986, the regional government has cleared approximately 30% of shrublands, reducing the amount of available combustible material. The burned area has decreased from an average of 1,060 ha/year in the period 1968-1986 to 222.6 ha/year between 1987 and 2023. It has also been found that pastures regenerated after clearing, as well as managed forest plantations (thinning and grazing), accumulate more SOC than the shrublands. In these marginalized mountains there are people who want to continue living off local resources. Extensive livestock farming can help retain the population, while also contributing to climate change mitigation and providing ecosystem services to society.