Trend Analysis of Reference Evapotranspiration in the São Francisco River Basin, Brazil

An important requisite in any water resources management program is the knowledge of the natural processes that regulate the hydrological cycle, especially for spatial and temporal analyses of these processes. This work aimed to explore spatial and temporal trends of reference evapotranspiration (ETo), evaluate ETo variation dynamics and quantify the contribution of each one of the meteorological variables in ETo calculation in the São Francisco River basin. Daily data of maximum and minimum air temperature, mean relative air humidity, wind speed and net radiation from 101 weather stations, for the period from 1961 to 2015, were used and are part of the network of the National Institute of Meteorology (INMET). Climate trend analysis was performed using the non-parametric Mann-Kendall statistical test and the sensitivity analysis for the Penman-Monteith equation was carried out based on partial derivatives as a function of the key meteorological variables of ETo (air temperature, net radiation, wind speed and actual water vapor pressure). A significant increase (p<0.01) in vapor pressure deficit (VPD) associated with the increase in mean air temperature contributed to increments in ETo along the studied period. The scenario in the entire São Francisco River basin is of increase in the values of the climatic variables, particularly evapotranspiration (85% of basin area with increments) and rainfall (52% of basin area with decrements). Results indicate an increase in ETo variation rates of approximately 2.424 mm year-2, on average, in the entire basin. The energy term represents higher weight in ETo calculation in 81% of the basin territory.

The Use of the Wheel in the Production of Pithoi: Preliminary Results and Lessons Learnt from Experimental Sessions

Large earthenware storage vessels, known as pithoi, were very widespread in the Mediterranean Basin area, both in domestic and non-domestic contexts, throughout the entire Bronze Age. From a technological point of view, due to their large dimensions, the production of pithoi is very demanding and requires highly skilled and expert artisans. However, despite their large diffusion and their prominent role in resource management, pithoi have received less attention in terms of research in comparison to other types of vessels; technological studies, in particular, stand out for their relative rarity. Indeed, experimental approaches are scant, thus preventing a comprehensive understanding of the manufacturing process of pithoi. This paper presents the preliminary results of two experimental sessions dedicated to the examination of the use of the wheel in the manufacture of these large clay containers. Experimental vessels have been analysed by way of the naked eye and through X-ray analysis.

Identifikasi dan Pencegahan Daerah Rawan Bencana Kebakaran Hutan dan Lahan Gambut Di Kalimantan Barat

Kalimantan Barat memiliki potensi bencana kebakaran hutan dan lahan gambut yang tinggi karena banyaknya titik api dan jenis lahan gambut yang mudah terbakar pada musim kemarau. Tujuan dari penelitian ini adalah untuk memetakan dan menentukan kecenderungan titik pamas dan mengidentifikasi dan mencegah kawasan rawan kebakaran hutan dan lahan gambut dengan data hotspot, peta curah hujan, peta tutupan lahan, peta kesatuan hidrologis gambut, dan peta cekungan air tanah menggunakan Sistem Informasi Geografis atau SIG. Metode overlap digunakan untuk menganalisis kecenderungan titik panas sedangkan Overlay dan Scoring digunakan untuk mengidentifikasi kawasan rawan kebakaran hutan dan lahan. Setelah dilakukan analisis titik panas, terdapat kecenderungan curah hujan pada kelas curah hujan 1.500-3.000 mm/tahun dengan 2.192 kejadian. Perubahan tutupan lahan di kawasan hutan mengalami penurunan sebesar 7,96%. Peningkatan tutupan lahan di kawasan non-hutan sebesar 11,26%, mempengaruhi potensi dan kecenderungan titik api dan bencana kebakaran hutan dan lahan. Kubu Raya memiliki tingkat kerawanan bencana kebakaran pada kelas sangat rawan dengan luasan 0,26%, dan Kapuas Hulu memiliki tingkat kerawanan bencana kebakaran pada kelas tidak rawan dengan luas 0,19%. Kabupaten Ketapang merupakan daerah dengan tingkat pencegahan tertinggi, dengan luas cekungan airtanah sebesar 26,46%.ABSTRACTWest Kalimantan has a high potential for forest and peatland fire disasters due to the high number of hotspots and the type of peatland which burns easily during the dry season. The purpose of this research is to map and determine the trend of hotspots and areas prone to forest and peatland fires and prevent them with hotspot data, rainfall maps, land cover maps, maps of peat hydrological units, and maps of groundwater basins using Geographic Information Systems or GIS. The overlap method is used to analyze the trend of hotspots; meanwhile, Overlay and Scoring are used to identify areas prone to forest and land fires in this research. After analyzing the hotspots, there is a tendency for rainfall with a class of 1,500-3,000mm/year with 2,192 events. Land cover change in forested areas decreased by 7.96%. It increased land cover in non-forest areas by 11.26%, affecting the potential and tendency of hotspots and forest and land fire disasters. Kubu Raya has a fire disaster vulnerability level in the very vulnerable class with an area of 0.26%, and Kapuas Hulu has a fire disaster vulnerability level in the non-prone class with an area of 0.19%. Ketapang Regency is the area with the highest prevention rate, with a groundwater basin area of 26.46%.

Damming Induced Natural Attenuation of Hydrothermal Waters by Runoff Freshwater Dilution and Sediment Biogeochemical Transformations (Sochagota Lake, Colombia)

The volcanic area of the Paipa system (Boyacá, Colombia) contains a magmatic heat source and deep fractures that help the flow of hot and highly mineralized waters, which are further combined with cold superficial inputs. This mixed water recharges the Salitre River and downstream feeding Sochagota Lake. The incoming water can contribute to substantial increases in hydrothermal SO42−-Na water in the water of the Salitre River basin area, raising the salinity. An additional hydrogeochemical process occurs in the mix with cold Fe-rich water from alluvial and surficial aquifers. This salinized Fe-rich water feeds the Sochagota Lake, although the impact of freshwaters from rain on the hydrochemistry of the Sochagota Lake is significant. A series of hydrogeochemical, biogeochemical, and mineralogical processes occur inside the lake. The aim of this work was to study the influence of damming in the Sochagota Lake, which acts as a natural attenuation of contaminants such as high concentrations of metals and salty elements coming from the Salitre River. Damming in the Sochagota Lake is considered to be an effective strategy for attenuating highly mineralized waters. The concentrations of dissolved elements were attenuated significantly. Dilution by rainfall runoff and precipitation of iron sulfides mediated by sulfate-reducing bacteria in deposits rich in organic material were the main processes involved in the attenuation of concentrations of SO42−, Fe, As Cu, and Co in the lake water. Furthermore, the K-consuming illitization processes occurring in the sediments could favor the decrease in K and Al.

Groundwater Resources Estimation in the Middle of Randublatung Groundwater Basin Based on Geoelectrical Investigation

The high groundwater use in the Randublatung Groundwater Basin area relates to groundwater abstraction for agriculture. Therefore, a question arises on how much groundwater resources in this area may support agricultural groundwater usage. This research has the objective to quantify the groundwater resources in this area. This research conducts a geoelectrical investigation to identify the aquifer’s lithology and observe the groundwater level. The research reveals that resistivity values of subsurface rock layers in the research area range from 0.13 to 124.86 Ωm. The aquifer layer consisted of two aquifer systems, with the hydraulic conductivity varies of the aquifer layer is 0.0001 cm/s until 0.01 cm/s. The aquifer layers estimated to be found at depths vary 5 – 90 m from the ground with thickness range from 10 to 70 m. Meanwhile, the aquiclude layers consisted of clay, silty clay, and sandy clay was estimated to be found at depths varies 0 – 50 m from the ground with thickness varies from 5 to 65 m. by combining those data with a hydraulic gradient of groundwater flow, the dynamic groundwater resources in the research area is estimated between 50 m3/day and 4,691 m3/day.

Comprehensive evaluation of the water environment carrying capacity of a river basin: a case study of the Weihe River Basin in China

By combining the analytic hierarchy process (AHP) and system dynamics (SD) models, a compound index system is established for simulating and evaluating the water environment carrying capacity (WECC) of the Weihe River Basin. The development tendencies of the population, economy, water resource demand and supply, water environment, water pollution, and water management were obtained from 2005 to 2040 by applying the five scenarios designed in this study. The results indicate that the comprehensive solution scenario was the optimal scenario, and the WECC would upgrade from a ‘general’ status to a ‘good’ status. Moreover, the blind pursuit of rapid economic growth is inadvisable, and it will compromise the sustainability of the river basin area. The river basin area should divert local development modes toward increased sustainability, emphasizing the coordinated development of society, the economy, and the environment.