Journal articles on the topic 'Semiarid rivers'
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Strauch, Ayron M. "Seasonal variability in faecal bacteria of semiarid rivers in the Serengeti National Park, Tanzania." Marine and Freshwater Research 62, no. 10 (2011): 1191. http://dx.doi.org/10.1071/mf11075.
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Humans and livestock are known contributors of faecal waste to surface water. However, little is known about natural fluctuations of faecal bacteria, especially where wildlife may contribute substantial amounts of waste. I tested the hypotheses that ecological factors, including seasonal animal impacts, rainfall and physiochemical water quality, influence the abundance of total coliform (TC) and Escherichia coli faecal bacteria in five rivers of the Serengeti National Park, Tanzania. TC and E. coli are indicators commonly used to assess water quality and their abundance can be determined quantitatively by using defined-substrate technology. Results demonstrated substantial variation in faecal bacteria across rivers and seasons. In the southern two rivers, faecal bacteria increased significantly during the wet season, compared with dry-season levels, whereas there were few seasonal differences in the northern rivers, suggesting that large populations of resident wildlife in the north dampen the seasonal influence of migratory wildlife. Faecal bacteria were positively related to rainfall and total ammonia/ammonium, and had a negative quadratic relationship with salinity. The present results demonstrated that wildlife in protected regions can be major contributors of faecal bacteria to surface waters, and as demand for water resources increases, pose a significant threat to human health.
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Wang, J., Y. S. Pei, K. J. Zhang, G. Gao, and Z. F. Yang. "Investigating the spatial–temporal variation of nitrogen cycling in an urban river in the North China Plain." Water Science and Technology 63, no. 11 (June 1, 2011): 2553–59. http://dx.doi.org/10.2166/wst.2011.537.
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Urban rivers are essential in retaining nutrients, but little is known about nitrogen cycling in these rivers in semiarid areas. We measured chemical and isotopic compositions of ammonium (NH4+-N) and nitrate (NO3−-N) to investigate spatial–temporal variation of nitrogen cycling in the Fuhe River in the North China Plain. Nitrogen pollution in the river was mainly induced by extra NH4+-N inputs which come from the discharges of urban sewage and effluents of wastewater treatment plants in upstream. NH4+-N obtained from decomposing organic matter of sediments can diffuse into the overlying water. Intense nitrification then occurs at the terrestrial–aquatic interface. Due to less vegetation in spring and autumn, loss of NH4+-N is mainly caused by nitrification. In contrast, significant NH4+-N is absorbed by plants in summer. NO3−-N generated from nitrification can be denitrified during the study period. The highest NO3−-N loss (about 86.3%) was observed in summer. The contribution of NO3−-N loss due to denitrification is 44.6%. The remaining 55.4% is due to plant uptake. The results suggested that nitrogen cycling in the river is related to temperature and dry–wet cycles. And vegetation restoration along the river could benefit the incremental improvements to the aquatic ecosystem.
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Oliveira, Regina Célia de, Anádria Stéphanie da Silva, André Rodolfo de Oliveira Ribeiro, José Erivaldo de Araújo, Odaci Fernandes de Oliveira, and Ramiro Gustavo Valera Camacho. "List of angiosperm species of the riparian vegetation of the Apodi-Mossoró River, Rio Grande do Norte, Brazil." Check List 9, no. 4 (August 1, 2013): 740. http://dx.doi.org/10.15560/9.4.740.
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This article describes the riparian vegetation of a river in the Rio Grande do Norte state for the first time. This is a seasonal river in the semiarid region of the Caatinga biome. The study is based on data from herbarium collections and new expeditions from July 2007 to October 2008. Two hundred and forty seven taxa were recorded and of these, 116 are herbs and three of which are epiphytes, 25 sub-shrubs, 77 shrubs or trees, 26 lianas, one parasite, and two palms. This list of species of riparian vegetation in the river Apodi-Mossoró was compared with only two available lists from rivers in the northeast with similar environmental characteristics and showed a low similarity. This study points to the need for preservation of the species and remnants of riparian vegetation of the river Apodi-Mossoró and to increase efforts in the study of this vegetation type.
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Millares, A., M. J. Polo, A. Moñino, J. Herrero, and M. A. Losada. "Bedload dynamics and associated snowmelt influence in mountainous and semiarid alluvial rivers." Geomorphology 206 (February 2014): 330–42. http://dx.doi.org/10.1016/j.geomorph.2013.09.038.
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Dong, Mingjia, Mingxiao Liu, Lina Yin, Jinjie Zhou, and Dongpo Sun. "Concept and Practices Involved in Comprehensive River Control Based on the Synergy among Flood Control, Ecological Restoration, and Urban Development: A Case Study on a Valley Reach of Luanhe River in a Semiarid Region in North China." Water 14, no. 9 (April 28, 2022): 1413. http://dx.doi.org/10.3390/w14091413.
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Many rivers in semiarid areas have ecological degradation and flood control problems that need to be addressed urgently. In order to maintain river health and to promote the sustainable development of cities near these rivers, a comprehensive river regulation project must be carried out. In this study, first, the factors influencing river health are discussed, and the principles and main restrictions involved in comprehensive regulations are studied. The scientific regulation mode is proposed, and new financing channels for water conservancy construction are also suggested. Second, a river reach adjacent to a city in the middle part of the Luanhe River in North China is used as a case study. The health status of the river is analyzed, and a comprehensive river regulation plan combined with urban development is put forward on this basis. The plan includes embankment construction, river regulations, multilevel rubber dam storage, ecological restoration, and artificial lake and riverside landscape construction. The influence of the engineering treatment on the river flood discharge capacity is examined, and the treatment effect is verified by a hydraulic scale model. After implementation of the comprehensive river regulations, the flood control safety of the city and river ecological environment are found to be significantly improved, with the hidden danger of dust storms eliminated. The treatment project incurs environmental, social, and economic benefits and preliminarily achieves the coordination and mutual promotion of river regulation and urban development.
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Sanz-Ronda, Bravo-Córdoba, Sánchez-Pérez, García-Vega, Valbuena-Castro, Fernandes-Celestino, Torralva, and Oliva-Paterna. "Passage Performance of Technical Pool-Type Fishways for Potamodromous Cyprinids: Novel Experiences in Semiarid Environments." Water 11, no. 11 (November 11, 2019): 2362. http://dx.doi.org/10.3390/w11112362.
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Endemic freshwater fish from semiarid environments are among the most threated species in the world due to water overexploitation and habitat fragmentation problems. Stepped or pool-type fishways are used worldwide to reestablish longitudinal connectivity and mitigate fish migration problems. Many of them are being installed or planned in rivers of semiarid environments, however, very few studies about fish passage performance through pool-type fishways has been carried out to date on these regions. The present work focuses on the passage performance of two potamodromous cyprinids endemic of these regions, with different ecological and swimming behavior: southern Iberian barbel (Luciobarbus sclateri) and Iberian straight-mouth nase (Pseudochondrostoma polylepis). These are assessed in two of the most common types of stepped fishways: vertical slot and submerged notch with bottom orifice fishways. Experiments were carried out during the spawning season in the Segura River (southeastern Spain), using a passive integrated transponder (PIT) tag and antenna system. Ascent success was greater than 80%, with a median transit time lower than 17 minutes per meter of height in all trials, and for both species and fishway types. Results show that both types of fishways, if correctly designed and constructed, provide interesting alternatives for the restoration of fish migration pathways in these regions.
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Warrick, Jonathan A., and John D. Milliman. "Hyperpycnal sediment discharge from semiarid southern California rivers: Implications for coastal sediment budgets." Geology 31, no. 9 (2003): 781. http://dx.doi.org/10.1130/g19671.1.
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St-Onge, Denis A., and Frans Gullentops. "Morphodynamics of Cold High Latitude Semiarid Regions: The Example of Ellef Ringnes Island, Nunavut*." Géographie physique et Quaternaire 59, no. 2-3 (April 4, 2007): 103–11. http://dx.doi.org/10.7202/014749ar.
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AbstractIn this paper we use the example of Ellef Ringnes Island, Nunavut, to examine active geomorphic processes in a high latitude semiarid region. The spectacular landscape of Ellef Ringnes Island is principally the result of fluvial erosion controlled by geological structure. The nival regime concentrates flow in a brief late-spring period which provides strong erosive capabilities for rivers in spite of low annual precipitation. Other processes related to the cold environment produce a variety of minor landforms such as patterned ground, mud flows associated with ground ice, and solifluction lobes.
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Jia, Xiaopeng, and Haibing Wang. "Element Geochemical Analysis of the Contribution of Aeolian Sand to Suspended Sediment in Desert Stream Flash Floods." Scientific World Journal 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/620610.
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The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.
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Zellman, Kristine L., Piret Plink-Björklund, and Henry C. Fricke. "Testing hypotheses on signatures of precipitation variability in the river and floodplain deposits of the Paleogene San Juan Basin, New Mexico, U.S.A." Journal of Sedimentary Research 90, no. 12 (February 18, 2021): 1770–801. http://dx.doi.org/10.2110/jsr.2020.75.
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ABSTRACTMuch progress has been made in recent years towards a set of recognition criteria for river discharge variability in river channel deposits, and thus sedimentary proxies for precipitation variability. Despite this progress, there is currently no consensus on how different styles of discharge variability are reflected in river sedimentary records, and whether variable-discharge river records from different climate types can be distinguished. Herein, river discharge and precipitation variability in the Paleogene is investigated using associations between river channel and floodplain deposits across the Paleocene–Eocene boundary from the Paleocene upper Nacimiento Formation and the early Eocene San Jose Formation in the San Juan Basin, New Mexico, USA.The succession is identified as deposits of variable-discharge river systems based on shared channel-deposit characteristics with modern and ancient variable-discharge river systems and the proposed facies models, in addition to alternations of poorly drained and well-drained floodplain deposits and/or slickensides indicating alternating wet–dry cycles. A long-term stratigraphic trend toward increasingly well-drained floodplain deposits is also observed and hypothesized to indicate successively more arid conditions from the Paleocene into the early Eocene. Comparisons with modern rivers from various climate zones suggest a long-term shift from a monsoonal climate in the Paleocene, to a fluctuating subhumid climate, ultimately leading to semiarid to arid conditions in the early Eocene. These observations suggest that floodplain deposits may be a better indicator of ambient climate, whereas channel deposits are records for frequency and magnitude of high-intensity precipitation events. Therefore, the existing facies models for variable-discharge rivers that consider only channel facies may not capture critical information needed to make accurate interpretations of paleoclimatic conditions. This study also adds to a growing body of evidence from geologic records of mid-latitude Paleogene river systems suggesting increases in the magnitude or variability of river discharge coinciding with established climate perturbations.
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Meixner, Thomas, Paul Brooks, James Hogan, Carlos Soto, and Scott Simpson. "Carbon and Nitrogen Export from Semiarid Uplands to Perennial Rivers: Connections and Missing Links, San Pedro River, Arizona, USA." Geography Compass 6, no. 9 (September 2012): 546–59. http://dx.doi.org/10.1111/j.1749-8198.2012.00510.x.
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Sarmento-Soares, Luisa Maria, and Ronaldo Fernando Martins-Pinheiro. "A fauna de peixes nas bacias do norte do Espírito Santo, Brasil." SITIENTIBUS série Ciências Biológicas 12, no. 1 (June 8, 2012): 27. http://dx.doi.org/10.13102/scb118.
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The hydrographic basins of northern Espírito Santo comprises the systems of Itaúnas and São Mateus rivers. The present work is part of a series of studies on the fish fauna along Espírito Santo’s river basins. Forty-nine geo-referred points in rivers and rivulets of the area were evaluated, 20 in the Itaúnas basin and 28 in São Mateus basin. The environment and the taxonomic composition of the fish fauna were documented at every point, reporting a total of 83 species, including 47 freshwater species and 36 marine, belonging to 35 families and 11 orders. Among the freshwater fish species, the Siluriformes predominated, with 20 species, followed by the Characiformes, with 17 species. The Atlantic forest of northern Espírito Santo, known as “floresta de tabuleiros”, was originally composed of ombrophylous forest as well as swamps, coastal sand dunes, and mangroves. With the suppression of native forests, the region has suffered from desertification, and environmental conditions are similar to the northeastern semiarid region, where the run-off waters are dispersed or intermittent. The loss of environmental quality along river valleys is associated with the need to reestablish riverine aquatic conditions. Exotic species and risks of introductions need further studies in these areas. Rare or endangered species whose distributional range has diminished in response to environmental changes may function as biological indicators. Potentially new species are identified, and regional endemism and distribution patterns for freshwater fishes are discussed.
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Abda, Zaki, Bilel Zerouali, Muwaffaq Alqurashi, Mohamed Chettih, Celso Augusto Guimarães Santos, and Enas E. Hussein. "Suspended Sediment Load Simulation during Flood Events Using Intelligent Systems: A Case Study on Semiarid Regions of Mediterranean Basin." Water 13, no. 24 (December 10, 2021): 3539. http://dx.doi.org/10.3390/w13243539.
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Sediment transport in rivers is a nonlinear natural phenomenon, which can harm the environment and hydraulic structures and is one of the main reasons for the dams’ siltation. In this paper, the following artificial intelligence approaches were used to simulate the suspended sediment load (SSL) during periods of flood events in the northeastern Algerian river basins: artificial neural network combined with particle swarm optimization (ANN-PSO), adaptive neuro-fuzzy inference system combined with particle swarm optimization (ANFIS-PSO), random forest (RF), and long short-term memory (LSTM). The comparison of the prediction accuracies of such different intelligent system approaches revealed that ANN-PSO, RF, and LSTM satisfactorily simulated the nonlinear process of SSL. Carefully comparing the results, the ANN-PSO model showed a slight superiority over the RF and LSTM models, with RMSE = 67.2990 kg/s in the Chemourah basin and RMSE = 55.8737 kg/s in the Gareat el tarf basin.
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Kerezsy, Adam, Stephen R. Balcombe, Angela H. Arthington, and Stuart E. Bunn. "Continuous recruitment underpins fish persistence in the arid rivers of far-western Queensland, Australia." Marine and Freshwater Research 62, no. 10 (2011): 1178. http://dx.doi.org/10.1071/mf11021.
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Fish living in highly variable and unpredictable environments need to possess life-history strategies that enable them to survive environmental extremes such as floods and drought. We used the length–frequency distributions of multiple fish species in multiple seasons and highly variable hydrological conditions to infer antecedent breeding behaviour in rivers of far-western Queensland, Australia. Hypotheses tested were as follows: (1) recruitment of some or all species of fish would occur within waterholes during no-flow periods; (2) there would be seasonal recruitment responses in some fish species; (3) recruitment of some species would be enhanced by channel flows and/or flooding. Hydrology and the incidence of flooding were highly variable across the study area during 2006–2008. Flood-influenced recruitment was evident for Hyrtl's tandan, Barcoo grunter and Welch's grunter. Silver tandan, golden goby, Cooper Creek catfish and Australian smelt showed evidence of seasonal recruitment unrelated to antecedent hydrology. However, most species demonstrated continual recruitment in isolated waterholes, irrespective of antecedent flow conditions and season. Continual and seasonal recruitment capabilities have obvious advantages over flood-pulse recruitment in rivers with highly unpredictable flood regimes and underpin the persistence of many fish species in arid and semiarid rivers.
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Albiero, Daniel, Marco Domingues da Silva, Rafaela Melo, Angel Pontin Garcia, Aline Castro Praciano, Francisco Belem Fernandes, Leonardo de Almeida Monteiro, Carlos Chioderoli, Alexsandro Oliveira da Silva, and José Delfino Barbosa Filho. "Economic Feasibility of Underwater Adduction of Rivers for Metropolises in Semiarid Coastal Environments: Case Studies." Water 10, no. 2 (February 16, 2018): 215. http://dx.doi.org/10.3390/w10020215.
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Higgisson, William, Dianne Gleeson, Linda Broadhurst, and Fiona Dyer. "Genetic diversity and gene flow patterns in two riverine plant species with contrasting life-history traits and distributions across a large inland floodplain." Australian Journal of Botany 68, no. 5 (2020): 384. http://dx.doi.org/10.1071/bt20074.
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Gene flow is a key evolutionary driver of spatial genetic structure, reflecting demographic processes and dispersal mechanisms. Understanding how genetic structure is maintained across a landscape can assist in setting conservation objectives. In Australia, floodplains naturally experience highly variable flooding regimes that structure the vegetation communities. Flooding plays an important role, connecting communities on floodplains and enabling dispersal via hydrochory. Water resource development has changed the lateral-connectivity of floodplain-river systems. One possible consequence of these changes is reduced physical and subsequent genetic connections. This study aimed to identify and compare the population structure and dispersal patterns of tangled lignum (Duma florulenta) and river cooba (Acacia stenophylla) across a large inland floodplain using a landscape genetics approach. Both species are widespread throughout flood prone areas of arid and semiarid Australia. Tangled lignum occurs on floodplains while river cooba occurs along rivers. Leaves were collected from 144 tangled lignum plants across 10 sites and 84 river cooba plants across 6 sites, on the floodplain of the lower and mid Lachlan River, and the Murrumbidgee River, NSW. DNA was extracted and genotyped using DArTseq platforms (double digest RADseq). Genetic diversity was compared with floodplain-river connection frequency, and genetic distance (FST) was compared with river distance, geographic distance and floodplain-river connection frequency between sites. Genetic similarity increased with increasing floodplain-river connection frequency in tangled lignum but not in river cooba. In tangled lignum, sites that experience more frequent flooding had greater genetic diversity and were more genetically homogenous. There was also an isolation by distance effect where increasing geographic distance correlated with increasing genetic differentiation in tangled lignum, but not in river cooba. The distribution of river cooba along rivers facilitates regular dispersal of seeds via hydrochory regardless of river level, while the dispersal of seeds of tangled lignum between patches is dependent on flooding events. The genetic impact of water resource development may be greater for species which occur on floodplains compared with species along river channels.
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Kotzian, Carla Bender, and Aline Monique Blank do Amaral. "Diversity and distribution of mollusks along the Contas River in a tropical semiarid region (Caatinga), Northeastern Brazil." Biota Neotropica 13, no. 4 (December 2013): 299–314. http://dx.doi.org/10.1590/s1676-06032013000400027.
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An inventory of macroinvertebrates conducted in the Contas River basin in Northeastern Brazil found 13 species of freshwater mollusks. Most of the community was represented by pulmonate gastropods, including Physa acuta, Drepanotrema anatinum, D. cimex, D. lucidum, Biomphalaria straminea?, Gundlachia radiata?, G. ticaga and Hebetancylus moricandi; the prosobranchs Pomacea archimedis?, Melanoides tuberculata and Littoridina sp. were also found. Bivalves were less diversified, represented only by Pisidium pulchellum? and Eupera simoni?. The taxonomic composition and the small size of many species reflect the intermittent condition of the basin. Additionally, the occurrence of shells of five terrestrial species (Helicina angulata, Gastrocopta pellucida hordeacella?, Beckianum beckianum, Succinea sp. and Systrophiidae gen. et sp. indet.) in the rivers reflects the occasional heavy rainfalls and floods in the region. The invasive gastropod M. tuberculata was the most abundant and widely distributed species. All 13 species were found in the lower course, in the Atlantic Forest region, and most, but not all, were recorded in the upper course, in the Caatinga region. The distribution and the occurrence of the bivalve species exclusively in the Atlantic Forest region indicate that the locally higher annual precipitation provides favorable conditions for the survival of these mollusks, such as a more stable hydroperiod.
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Henry, Mary C., John K. Maingi, and Jessica McCarty. "Fire on the Water Towers: Mapping Burn Scars on Mount Kenya Using Satellite Data to Reconstruct Recent Fire History." Remote Sensing 11, no. 2 (January 9, 2019): 104. http://dx.doi.org/10.3390/rs11020104.
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Mount Kenya is one of Kenya’s ‘water towers’, the headwaters for the country’s major rivers including the Tana River and Ewaso Nyiro River, which provide water and hydroelectric power to the semiarid region. Fires affect water downstream, but are difficult to monitor given limited resources of local land management agencies. Satellite-based remote sensing has the potential to provide long term coverage of large remote areas on Mount Kenya, especially using the free Landsat data archive and moderate resolution imaging spectroradiometer (MODIS) fire products. In this study, we mapped burn scars on Mount Kenya using 30 m Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI) derived dNBR (change in normalized burn ratio) and MODIS active fire detection and burned area data for fires occurring from 2004 to 2015. We also analyzed topographic position (elevation, slope, aspect) of these fires using an ASTER global digital elevation model (GDEM v2) satellite-derived 30 m digital elevation model (DEM). Results indicate that dNBR images calculated from data acquired about one year apart were able to identify large fires on Mount Kenya that match locations (and timing) of MODIS active fire points and burned areas from the same time period, but we were unable to detect smaller and/or older fires.
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Qiao, Shufeng, Rui Ma, Ziyong Sun, Mengyan Ge, Jianwei Bu, Junyou Wang, Zheng Wang, and Han Nie. "The Effect of Water Transfer during Non-growing Season on the Wetland Ecosystem via Surface and Groundwater Interactions in Arid Northwestern China." Remote Sensing 12, no. 16 (August 5, 2020): 2516. http://dx.doi.org/10.3390/rs12162516.
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The use of ecological water transfer to maintain the ecological environment in arid or semiarid regions has become an important means of human intervention to alleviate vegetation ecosystem degradation in arid and semiarid areas. The water transfer to downstream in a catchment is often carried out during the non-growing season, due to the competitive water use between the upper and middle reaches and lower reaches of rivers. However, the impacts and mechanism of artificial water transfer on vegetation and wetland ecosystem restoration have not been thoroughly investigated, especially in northwest China. Taking the Qingtu Lake wetland system in the lower reaches of the Shiyang River Catchment as the study area, this study analyzed the spatial and temporal distribution surface area of Qingtu Lake and the surrounding vegetation coverage before and after water transfer, by interpreting remote sensing data, the variation of water content in the vadose zone, and the groundwater level by obtaining field monitoring data, as well as the correlation between the water body area of Qingtu Lake and the highest vegetation coverage area in the following year. The conclusion is that there is a positive correlation between the water body area of Qingtu Lake in autumn and the vegetation coverage in each fractional vegetation coverage (FVC) interval in the next summer, especially in terms of the FVC of 30–50%. The groundwater level and soil water content increase after water transfer and remain relatively high for the following months, which suggests that transferred water from upstream can be stored as groundwater or soil water in the subsurface through surface water and subsurface water interaction. These water sources can provide water for the vegetation growth the next spring, or support plants in the summer.
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de Freitas Barros Neto, Luciano, Rafael Gomes Frigo, Simone Almeida Gavilan, Sérgio Adriane Bezerra de Moura, and Sergio Maia Queiroz Lima. "Barbel development associated to aquatic surface respiration in Triportheus signatus (Characiformes: Triportheidae) from the semiarid Caatinga rivers." Environmental Biology of Fishes 103, no. 1 (December 1, 2019): 89–98. http://dx.doi.org/10.1007/s10641-019-00935-x.
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Diehl, Rebecca M., Andrew C. Wilcox, and John C. Stella. "Evaluation of the integrated riparian ecosystem response to future flow regimes on semiarid rivers in Colorado, USA." Journal of Environmental Management 271 (October 2020): 111037. http://dx.doi.org/10.1016/j.jenvman.2020.111037.
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Li, Junxia, Xueping Bai, Yuting Jin, Fangbo Song, Zhenju Chen, Lixin Cai, Fenghua Zou, Mengzhu Jiang, Ruixin Yun, and Zhaoyang Lv. "Recent Intensified Runoff Variability in the Hailar River Basin during the Past Two Centuries." Journal of Hydrometeorology 21, no. 10 (October 1, 2020): 2257–73. http://dx.doi.org/10.1175/jhm-d-19-0274.1.
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AbstractUsing tree-ring data of Pinus sylvestris var. mongolica from the Hulun Buir region in northeast China, 12 annual runoff series of the Hailar River spanning the past 202–216 years were established for the first time; these included 11 branches and one for the entire basin. These reconstructions, which could explain 29.4%–52.7% of the total variance for the measured runoffs during 1956–2006, performed well in statistical verification tests. In the whole basin’s reconstruction of 212 years, 34 extreme drought years (16.0%) and 41 extreme pluvial years (19.3%) were identified; 4 of the 10 most extreme years occurred after 1980. The consistent cycle and correlation revealed that the Hailar runoff had a teleconnection with the El Niño–Southern Oscillation (ENSO). The sharply increasing variance at the end of the reconstruction, accompanied by the increasing intensity of short cycles (4–8 years), indicated that runoff variability in the Hailar River basin has enhanced in the late twentieth century. This is verified by the drastic fluctuations in water level and area of rivers and lakes, and the frequent shift of natural land cover types in the Hulun Buir area in recent decades. The intensified runoff variability can be connected with the concurrently enhanced ENSO activity. Our study is the first to identify the intensification of recent runoff variability in the semiarid to arid region in northeast China from a long-term perspective. With projected enhancement of ENSO activity, the Hailar River basin will face the increased risk of extreme hydrological events.
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Ferreira Paiva, Franciely, Dalescka Barbosa de Melo, Lucianna Marques Rocha Ferreira, and Joseline Molozzi. "RESPONSE OF TAXONOMIC AND FUNCTIONAL BENTHIC MACROFAUNA RICHNESS TO LAND USE AND LAND COVER AT BRAZILIAN RESERVOIRS DURING EXTREME DROUGHT." Environmental Smoke 5, no. 2 (August 31, 2022): 27. http://dx.doi.org/10.32435/envsmoke.20225227.
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Introduction: Reservoirs are artificial aquatic ecosystems created by damming rivers, and are influenced by different sorts of impacts. Anthropic land use and occupation are one of the main causes of the loss of environmental quality and biological diversity in aquatic ecosystems. The objective of this work was to evaluate the effects of land use and occupation on the taxonomic and functional richness of benthic macroinvertebrates in reservoirs in the Brazilian semiarid region during a period of extreme drought. Material and methods: The study was conducted in six reservoirs located in the semiarid region from Brazilian Northeast (Paraíba and Rio Grande do Norte states): Sabugí, Passagem das Traíras, Cruzeta, Cordeiro, Sumé and Poções. The collections of benthic macrofauna, physical and chemical variables of water and the mapping of land use and occupation were performed for the years 2014 and 2019, in June and September. The sampling period was characterized as the most severe drought in the last 50 years in this study area. The land use and occupation were verified through the semi-supervised classification method of images captured by the Landsat 8 satellite, within 100 meters of the reservoir margin. The diversity of benthic macrofauna was analyzed through the taxonomic richness and functional richness, according to five functional characteristics: feeding trophic groups, breathing mode, voltinism, body size and body protection. To check for significant differences in physical and chemical water variables and taxonomic and functional richness among land use and land cover categories we performed PERMANOVA test. Results and Discussion: Seven land use and land cover categories were found in the reservoirs studied in the years 2014 and 2019, these are: water, agriculture, pasture, exposed soil, human occupation, open vegetation (native and exotic species of small/medium size with continuous spacing) and tree/shrub vegetation (native and exotic species of medium/large size with associated herbaceous stratum and predominance of semi-continuous dorsel). In all reservoirs the prevalent-use was pasture. Physical and chemical variables of water varied significantly among land use and land cover types, they were soluble reactive phosphate (p=0.02), total phosphorus (p=0.002) and water volume (p=0.01). The highest concentrations of total phosphorus were associated with predominant human occupation and soluble reactive phosphate with agriculture. The highest percentage of water volume was associated with a predominant use of tree/shrub vegetation. In reservoirs of semiarid regions with low connectivity due to intermittent rivers and extreme drought periods, adjacent anthropic activities such as agriculture, pasture and human occupation are the main external sources of nutrients. The taxonomic and functional richness of benthic macrofauna was higher in areas of open vegetation, however, it did not vary significantly between land use and land cover categories. Conclusions: Our results show that the effects of anthropic use and occupation in reservoirs associated with water scarcity lead to the homogenization of the macrobenthic community, which can generate negative consequences in processes sustained by the community.
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Rizki, L. Muh Fathur, Nofrohu Retongga, Andika Gerardus Oratmangun, Abdurrahman Saputra, Atikah Zahidah, Diana Septiani Roos, Rohmad Bagus Abadi, and Oan Marcello Lukas Watania. "Studi Provenance Batupasir Karbonatan Formasi Kerek Dengan Metode Point Counting Di Daerah Kandangan Kabupaten Semarang." Jurnal Teknologi 14, no. 2 (December 19, 2021): 164–69. http://dx.doi.org/10.34151/jurtek.v14i2.3728.
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Carbonate sandstone in the study area was found around rivers and hills in the study area. Provenance of sandstones in the research area of interest to be examined, because not known provenance the sandstone rock formations karbonatan Kerek especially in the research area. The purpose of this study was to determine the provenance of Kerek carbonated sandstones in the study area using themethod point counting. The methodology used for the analysis of Provenance in the study area is using petrographic incisions. The results of the analysis of provenance on the five samples of carbonated sandstones of the Kerek Formation in the study area obtained data in the form of: rock types including lithic arenite (Pettijohn, 1975), the climate of the source area is semiarid (Nelson, 2007), the source rock type is plutonic rock (Tartosa, et al, 1991). ) and its tectonic setting is in the magmatic arc transitional arc sub-zone (Dickinson and Suczek, 1979).
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Lou, Sha, Wenrui Huang, Shuguang Liu, and Guihui Zhong. "Scarcity of Drinking Water in Taihu Lake Basin, China: A Case Study of Yixing City." Water 11, no. 2 (February 20, 2019): 362. http://dx.doi.org/10.3390/w11020362.
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: Water use has been growing globally at more than twice the rate of the population increase over the last century. Water scarcity is one of the main problems facing the world, especially the scarcity of clean and safe drinking water. Scarcity of drinking water is not only relevant in arid or semiarid regions, but also occurs in water-rich regions due to the decline in water quantity caused by pollution or salinity intrusion. As a part of Taihu Lake Basin, a famous water-rich region in China, Yixing City has a total area of 1996.6 km2, including 242.29 km2 from Taihu Lake, 215 rivers with an area of 130 km2, more than 20 ponds with an area of 0.05 km2, and 20 reservoirs with a total capacity of 126 million m3. There always has enough water in Yixing City. However, meteorological conditions and water quality both affect the available drinking water sources. Poor-quality water was used as a drinking water source in Yixing City during a drought event in 2011. Approximately 1.4 × 107 m3 of poor-quality water was used for drinking water in Yixing city, providing 37.13% of the total drinking water. It was a source of concern that the water quality was too poor to be used as drinking water and that the water treatment processes were expensive. The scarcity of drinking water has become a serious issue, not only in arid and semiarid regions but also in water towns such as Taihu Lake Basin, and this issue requires society’s attention. Many measures should be taken to relieve the drinking water shortage, such as seeking new drinking water sources, protecting the current water source areas, controlling pollution emissions, and implementing effective water resource management.
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Morgado, Fernando, Ruy M. A. L. Santos, Daniela Sampaio, Luiz Drude de Lacerda, Amadeu M. V. M. Soares, Hugo C. Vieira, and Sizenando Abreu. "Chronological Trends and Mercury Bioaccumulation in an Aquatic Semiarid Ecosystem under a Global Climate Change Scenario in the Northeastern Coast of Brazil." Animals 11, no. 8 (August 13, 2021): 2402. http://dx.doi.org/10.3390/ani11082402.
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Due to global warming, in the northeastern semiarid coastal regions of Brazil, regional and global drivers are responsible for decreasing continental runoff and increasing estuarine water residence time, which promotes a greater mobilization of bioavailable mercury (Hg) and allows increasing fluxes and/or bioavailability of this toxic trace element and an acceleration of biogeochemical transformation of Hg. In this work, an application of dendrochemistry analysis (annular tree rings analysis) was developed for the reconstruction of the historical pattern of mercury contamination in a contaminated area, quantifying chronological Hg contamination trends in a tropical semiarid ecosystem (Ceará River Estuary, northeastern coast of Brazil) through registration of mercury concentration on growth rings in specimens of Rhizophora mangle L. and using the assessment in sediments as a support for the comparison of profiles of contamination. The comparison with sediments from the same place lends credibility to this type of analysis, as well as the relationship to the historical profile of contamination in the region, when compared with local data about industries and ecological situation of sampling sites. In order to evaluate the consequences of the described increase in Hg bioavailability and bioaccumulation in aquatic biota, and to assess the biological significance of Hg concentrations in sediments to fish and wildlife, muscle and liver from a bioindicator fish species, S. testudineus, were also analyzed. The results of this work reinforce the indicators previously described in the semiarid NE region of Brazil, which showed that global climate change and some anthropogenic factors are key drivers of Hg exposure and biomagnification for wildlife and humans. Considering the Hg concentration present in the top layers of sediment (~20 cm around 15 to 20 years) with the outer layers in the tree ring cores and in the sediment’s cores from Pacoti estuary and the Ceará estuary, overall the data indicate an increase in mercury in recent years in the Hg surface sediments, especially associated with the fine sediment fraction, mainly due to the increased capacity of small particles to adsorb Hg. There was revealed a positive and significant correlation (p < 0.05) between Hg trends in sediments and Hg trends in annular tree rings. This shared Hg pattern reflects local environmental conditions. The Hg concentration values in S. testudineus from both study areas are not restrictive to human consumption, being below the legislated European limit for Hg in foodstuffs. The results from S. testudineus muscles analysis suggest a significant and linear increase in Hg burden with increasing fish length, indicating that the specimens are accumulating Hg as they grow. The results from both rivers show an increase in BSAF with fish growth. The [Hg] liver/[Hg] muscles ratio >1, which indicates that the S. testudineus from both study areas are experiencing an increase in Hg bioavailability. Possible climate-induced shifts in these aquatic systems processes are inducing a greater mobilization of bioavailable Hg, which could allow an acceleration of the biogeochemical transformation of Hg.
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Arendt, Robert, Christian Reinhardt-Imjela, Achim Schulte, Leona Faulstich, Tobias Ullmann, Lorenz Beck, Sandro Martinis, Petrina Johannes, and Joachim Lengricht. "Natural Pans as an Important Surface Water Resource in the Cuvelai Basin—Metrics for Storage Volume Calculations and Identification of Potential Augmentation Sites." Water 13, no. 2 (January 13, 2021): 177. http://dx.doi.org/10.3390/w13020177.
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Numerous ephemeral rivers and thousands of natural pans characterize the transboundary Iishana-System of the Cuvelai Basin between Namibia and Angola. After the rainy season, surface water stored in pans is often the only affordable water source for many people in rural areas. High inter- and intra-annual rainfall variations in this semiarid environment provoke years of extreme flood events and long periods of droughts. Thus, the issue of water availability is playing an increasingly important role in one of the most densely populated and fastest growing regions in southwestern Africa. Currently, there is no transnational approach to quantifying the potential storage and supply functions of the Iishana-System. To bridge these knowledge gaps and to increase the resilience of the local people’s livelihood, suitable pans for expansion as intermediate storage were identified and their metrics determined. Therefore, a modified Blue Spot Analysis was performed, based on the high-resolution TanDEM-X digital elevation model. Further, surface area–volume ratio calculations were accomplished for finding suitable augmentation sites in a first step. The potential water storage volume of more than 190,000 pans was calculated at 1.9 km3. Over 2200 pans were identified for potential expansion to facilitate increased water supply and flood protection in the future.
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Díaz Mendoza, Claudia. "Alternatives for erosion control by using conventional coverage, non-conventional coverage and revegetation." Ingeniería e Investigación 31, no. 3 (September 1, 2011): 80–90. http://dx.doi.org/10.15446/ing.investig.v31n3.26390.
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Humankind's unsustainable behaviour regarding land-use has negative effects on the environment, leading to loss of fertility and degradation and desertification; this has a direct impact on the decline and deterioration of water resources, soil erosion and thus changes in the weather leading to drier conditions. The foregoing are caused by the misuse of soil. The way soil resources have suffered gradual deterioration has become evident in Colombia during recent years; this has been produced by erosion and the removal of mass caused by various factors including physical and chemical erosion. All the above, together with negative events such as global climate change and the sedimentation of rivers, means a negative environmental impact. Soil erosion and desertification are major environmental issues regarding disturbances and threats affecting the arid, semiarid and dry sub-humid Mediterranean region's geo-ecosystems in the third millennium; additionally, economic global change may exacerbate such problems (Ingram et al., 1996; Williams et al., 1996). Regarding soil deterioration, soil vegetation cover and erosion control and mitigation measures should be introduced by using mechanisms which should be as natural as possible and do not induce fresh impacts on the environment. This literature review has thus documented the state of the art regarding several alternatives for erosion control currently involving bioengineering.
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Tapia, Javier, Jorge Bielsa, Yolanda Martínez, Sabine Sauvage, Roxelane Cakir, Mélanie Raimonet, Magali Gerino, and José Miguel Sánchez-Pérez. "Economic valuation of the natural service of nitrate regulation provided by rivers including dilution effects: Application to a semiarid region, the Ebro basin (Spain)." Ecological Indicators 117 (October 2020): 106608. http://dx.doi.org/10.1016/j.ecolind.2020.106608.
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Ruhoff, Anderson, Bruno Comini de Andrade, Leonardo Laipelt, Ayan Santos Fleischmann, Vinícius Alencar Siqueira, Adriana Aparecida Moreira, Rafael Barbedo, et al. "Global Evapotranspiration Datasets Assessment Using Water Balance in South America." Remote Sensing 14, no. 11 (May 25, 2022): 2526. http://dx.doi.org/10.3390/rs14112526.
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Evapotranspiration (ET) connects the land to the atmosphere, linking water, energy, and carbon cycles. ET is an essential climate variable with a fundamental importance, and accurate assessments of the spatiotemporal trends and variability in ET are needed from regional to continental scales. This study compared eight global actual ET datasets (ETgl) and the average actual ET ensemble (ETens) based on remote sensing, climate reanalysis, land-surface, and biophysical models to ET computed from basin-scale water balance (ETwb) in South America on monthly time scale. The 50 small-to-large basins covered major rivers and different biomes and climate types. We also examined the magnitude, seasonality, and interannual variability of ET, comparing ETgl and ETens with ETwb. Global ET datasets were evaluated between 2003 and 2014 from the following datasets: Breathing Earth System Simulator (BESS), ECMWF Reanalysis 5 (ERA5), Global Land Data Assimilation System (GLDAS), Global Land Evaporation Amsterdam Model (GLEAM), MOD16, Penman–Monteith–Leuning (PML), Operational Simplified Surface Energy Balance (SSEBop) and Terra Climate. By using ETwb as a basis for comparison, correlation coefficients ranged from 0.45 (SSEBop) to 0.60 (ETens), and RMSE ranged from 35.6 (ETens) to 40.5 mm·month−1 (MOD16). Overall, ETgl estimates ranged from 0 to 150 mm·month−1 in most basins in South America, while ETwb estimates showed maximum rates up to 250 mm·month−1. ETgl varied by hydroclimatic regions: (i) basins located in humid climates with low seasonality in precipitation, including the Amazon, Uruguay, and South Atlantic basins, yielded weak correlation coefficients between monthly ETgl and ETwb, and (ii) tropical and semiarid basins (areas where precipitation demonstrates a strong seasonality, as in the São Francisco, Northeast Atlantic, Paraná/Paraguay, and Tocantins basins) yielded moderate-to-strong correlation coefficients. An assessment of the interannual variability demonstrated a disagreement between ETgl and ETwb in the humid tropics (in the Amazon), with ETgl showing a wide range of interannual variability. However, in tropical, subtropical, and semiarid climates, including the Tocantins, São Francisco, Paraná, Paraguay, Uruguay, and Atlantic basins (Northeast, East, and South), we found a stronger agreement between ETgl and ETwb for interannual variability. Assessing ET datasets enables the understanding of land–atmosphere exchanges in South America, to improvement of ET estimation and monitoring for water management.
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Granados, Alfredo, Alvaro Sordo-Ward, Bolívar Paredes-Beltrán, and Luis Garrote. "Exploring the Role of Reservoir Storage in Enhancing Resilience to Climate Change in Southern Europe." Water 13, no. 1 (January 1, 2021): 85. http://dx.doi.org/10.3390/w13010085.
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Recent trends suggest that streamflow discharge is diminishing in many rivers of Southern Europe and that interannual variability is increasing. This threatens to aggravate water scarcity problems that periodically arise in this region, because both effects will deteriorate the performance of reservoirs, decreasing their reliable yield. Reservoir storage is the key infrastructure to overcome variability and to enhance water availability in semiarid climates. This paper presents an analysis of the role of reservoir storage in preserving water availability under climate change scenarios. The study is focused on 16 major Southern European basins. Potential water availability was calculated in these basins under current condition and for 35 different climatic projections for the period 2070–2100. The results show that the expected reduction of water availability is comparable to the decrease of the mean annual flow in basins with large storage capacity. For basins with small storage, the expected reduction of water availability is larger than the reduction of mean annual flow. Additionally, a sensitivity analysis was carried out by replicating the analysis assuming variable reservoir volumes from 25% to 175% of current storage. The results show that increasing storage capacity attenuates the reduction of water availability and reduces its uncertainty under climate change projections. This feature would allow water managers to develop suitable policies to mitigate the impacts of climate change, thus enhancing the resilience of the system.
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Vallejo, Mariana, M. Isabel Ramírez, Alejandro Reyes-González, Jairo López-Sánchez, and Alejandro Casas. "Agroforestry Systems of the Tehuacán-Cuicatlán Valley: Land Use for Biocultural Diversity Conservation." Land 8, no. 2 (January 23, 2019): 24. http://dx.doi.org/10.3390/land8020024.
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The Tehuacán-Cuicatlán Valley, Mexico, is the semiarid region with the richest biodiversity of North America and was recently recognized as a UNESCO's World Heritage site. Original agricultural practices remain to this day in agroforestry systems (AFS), which are expressions of high biocultural diversity. However, local people and researchers perceive a progressive decline both in natural ecosystems and AFS. To assess changes in location and extent of agricultural land use, we carried out a visual interpretation of very-high resolution imagery and field work, through which we identified AFS and conventional agricultural systems (CAS) from 1995 to 2003 and 2012. We analyzed five communities, representative of three main ecological and agricultural zones of the region. We assessed agricultural land use changes in relation to conspicuous landscape features (relief, rivers, roads, and human settlements). We found that natural ecosystems cover more than 85% of the territory in each community, and AFS represent 51% of all agricultural land. Establishment and permanence of agricultural lands were strongly influenced by gentle slopes and the existence of roads. Contrary to what we expected, we recorded agricultural areas being abandoned, thus favoring the regeneration of natural ecosystems, as well as a 9% increase of AFS over CAS. Agriculture is concentrated near human settlements. Most of the studied territories are meant to preserve natural ecosystems, and traditional AFS practices are being recovered for biocultural conservation.
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Zerhouni, Youssef, Saida Alikouss, Najib Saber, Samiha Nfissi, Ghalem Zahour, Zouhir Baroudi, and Mohamed Samir. "Caractérisation Des Boues De Sucrerie Et Des Argiles Pour La Neutralisation Des Résidus Miniers Acides De La Mine De Kettara (Jebilet Centrales, Maroc)." European Scientific Journal, ESJ 12, no. 15 (May 30, 2016): 321. http://dx.doi.org/10.19044/esj.2016.v12n15p321.
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The minerals in the tailings, subject to the action of water and atmospheric oxygen, can generate Acid Mine Drainage (AMD). The latter is considered the most important environmental issue facing the mining industry. Its environmental impacts include the destruction of the flora and fauna in infected rivers and contamination of groundwater. The abandoned mine site Kettara, located about 32 km northwest of Marrakech (Morocco), chosen as a pilot site for this study, more than 3 million tons of tailings stored at ground level without any concern for their environmental consequences. These solid residues, with high concentrations of heavy metals (As, Pb, Fe, Cu ...), produce leachate very acidic (pH <2.9) may contaminate the water resources of the region. To mitigate the DMA phenomenon in this mining site, different protocols have been proposed using candy sludge (Mud Pulp Sweets: MPS), rich in carbonates from the Moroccan Sugar Company Unit (COSUMAR) and red clays (Clays: CLY) of the city of Safi. Physicochemical characterization and mineralogical of these two materials was performed an provided promising results regarding the effectiveness of the use of alkaline materials in the stabilization of tailings Kettara. Indeed, these starting materials are provided with a net neutralizing power which is of the order of 878.5 kg CaCO3 / t for MPS and 299 kg CaCO3 / t for CLY. The valuation of MPS and CLY, as a main component of an alkaline amendment, is likely to significantly reduce the effects of DMA in this semiarid climate mine.
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Santos, Alexandre C. A., and Nuno Caiola. "Environmental typology of rivers from the Brazilian semiarid as a first step for the application of the index of biotic integrity: The case of the Chapada Diamantina." River Research and Applications 36, no. 7 (March 2, 2020): 1151–59. http://dx.doi.org/10.1002/rra.3613.
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Reinecke, Robert, Laura Foglia, Steffen Mehl, Tim Trautmann, Denise Cáceres, and Petra Döll. "Challenges in developing a global gradient-based groundwater model (G<sup>3</sup>M v1.0) for the integration into a global hydrological model." Geoscientific Model Development 12, no. 6 (June 18, 2019): 2401–18. http://dx.doi.org/10.5194/gmd-12-2401-2019.
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Abstract. In global hydrological models, groundwater (GW) is typically represented by a bucket-like linear groundwater reservoir. Reservoir models, however, (1) can only simulate GW discharge to surface water (SW) bodies but not recharge from SW to GW, (2) provide no information on the location of the GW table, and (3) assume that there is no GW flow among grid cells. This may lead, for example, to an underestimation of groundwater resources in semiarid areas where GW is often replenished by SW or to an underestimation of evapotranspiration where the GW table is close to the land surface. To overcome these limitations, it is necessary to replace the reservoir model in global hydrological models with a hydraulic head gradient-based GW flow model. We present G3M, a new global gradient-based GW model with a spatial resolution of 5′ (arcminutes), which is to be integrated into the 0.5∘ WaterGAP Global Hydrology Model (WGHM). The newly developed model framework enables in-memory coupling to WGHM while keeping overall runtime relatively low, which allows sensitivity analyses, calibration, and data assimilation. This paper presents the G3M concept and model design decisions that are specific to the large grid size required for a global-scale model. Model results under steady-state naturalized conditions, i.e., neglecting GW abstractions, are shown. Simulated hydraulic heads show better agreement to observations around the world compared to the model output of de Graaf et al. (2015). Locations of simulated SW recharge to GW are found, as is expected, in dry and mountainous regions but areal extent of SW recharge may be underestimated. Globally, GW discharge to rivers is by far the dominant flow component such that lateral GW flows only become a large fraction of total diffuse and focused recharge in the case of losing rivers, some mountainous areas, and some areas with very low GW recharge. A strong sensitivity of simulated hydraulic heads to the spatial resolution of the model and the related choice of the water table elevation of surface water bodies was found. We suggest to investigate how global-scale groundwater modeling at 5′ spatial resolution can benefit from more highly resolved land surface elevation data.
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Huang, Guanwen, Hai Zhu, Juqing Zhang, and Bohan Liu. "Analysis of the Characteristics of Climate Change in the Ecologically Vulnerable Area of the Mu Us Dune Field under the Background of Global Warming." Remote Sensing 13, no. 4 (February 9, 2021): 627. http://dx.doi.org/10.3390/rs13040627.
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The Mu Us dune field is one of China’s four major dune fields, which are ecologically vulnerable areas of northwest semiarid land across Shaanxi, Ningxia, and Inner Mongolia, also very sensitive to the global temperature rise and environmental changes. This paper uses data on the temperature, precipitation, and precipitable water vapor (PWV) in the Mu Us dune field and its surrounding areas to analyze and discuss the time series and spatial distribution characteristics of these three factors in this area. The results of the study show that, in recent years, the trend of temperature increase in the Mu Us dune field has been higher than the average level in China, but this trend has gradually subsided since 2000. The spatial distribution of temperature presents an obvious characteristic of gradual increase from north to south and is affected by latitude, altitude, and topography. The annual cumulative precipitation of the Mu Us dune field is lower than the average level in China. However, in recent years, the rate of the increase in precipitation in this area has been significantly higher than that of the average rate of increase in China. The eastern part of the dune field has the most precipitation, which gradually decreases to the west. The spatial distribution of precipitation is greatly affected by monsoon factors in the region and the distribution of rivers. In the research field, PWV has been rising in recent years, which is greatly related to the increase of vegetation coverage in this region. This demonstrates that the Mu Us dune field has experienced a “warmer and wetter” trend in recent years.
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Buraeva, E. A., O. S. Bezuglova, S. N. Gorbov, D. V. Ivankov, T. A. Mikhailova, E. A. Kashchayeva, N. V. Malomyzheva, D. A. Shvetsova, and A. A. Shiryaeva. "FEATURES OF RADIONUCLIDES DISTRIBUTION IN TERRESTRIAL ECOSYSTEMS OF THE CHESTNUT ZONE IN THE CONDITIONS OF THE ROSTOV REGION." UNIVERSITY NEWS. NORTH-CAUCASIAN REGION. NATURAL SCIENCES SERIES, no. 4 (212) (December 28, 2021): 34–44. http://dx.doi.org/10.18522/1026-2237-2021-4-34-44.
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The determination of the radioactivity of soils in settlements and natural territories is necessary to identify areas with an increased level of radionuclide content. The paper is devoted to studying the features of accumulation of natural radionuclides (226Ra, 232Th, 40K) and artificial 137Cs by plants in the conditions of semiarid steppes on the example of the chestnut zone of the Rostov region. Samples of soils and plants selected in the Tsimlyansky, Volgodonsky, Dubovsky and Orlovsky districts of the Rostov region during the 2014-2017 expeditions were used as objects of research. The activity concentration of radionuclides in soil and plants was measured by gamma spectrometric method of radionuclide analysis. It is shown that the distribution of artificial radionuclide 137Cs in the soil cover of the Rostov region, caused by the accident at the Chernobyl nuclear power plant, is extremely uneven and depends on the humus content. Biogenic element 40K accumulates in the surface horizon, also correlating with the humus content. The activity concentration of 137Cs content on 40K is most clearly displayed in the upper layer (0-10 cm). The lowest activity concentration of natural radionuclides is typical for alluvial-meadow soils and salt marshes of lightweight granulometric composition formed in floodplains of rivers and on coastal areas of lake Manych-Gudilo. In chestnut and dark-chestnut soils, the activity concentration of natural radionuclides is almost comparable, since variations in the activity concentration of these radionuclides in these soils are within the measurement error (10-15 %). The aggregated transfer factors from soil to plants for all radionuclides were generally less than 0.4 m2/kg. Variations in radionuclide aggregated transfer factors in the ecosystem are caused by climatic conditions during the selection period and, as a result, by mechanical contamination of soil particles and dust both during rains and during droughts, when the soil begins to dust.
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Yin, Jun, Denghua Yan, Zhiyong Yang, Zhe Yuan, Yong Yuan, Hao Wang, and Xiaoliang Shi. "Research on Historical and Future Spatial-Temporal Variability of Precipitation in China." Advances in Meteorology 2016 (2016): 1–14. http://dx.doi.org/10.1155/2016/9137201.
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Based on observed data and data simulated by climate models, temporal variation and spatial distribution of precipitation in China from 1961 to 2050 were investigated. The slope of annual precipitation and Mann-Kendall statistical test were applied to quantify the trend magnitude and detect the significant trend, respectively. Besides, decadal and interannual variations of different rain belts were analyzed to reveal the spatial changing pattern of precipitation. Results indicated the following. (1) During 1961–2011, annual precipitation in Haihe River Basin decreased significantly while the annual precipitation in river basins in the northwest increased significantly. Although the annual precipitation of Yangtze River Basin has an indistinctive decreasing trend, that in the middle and lower reaches has increased and that in the upper reaches has decreased. Arid zone and humid zone are shrinking while semiarid and semihumid zone are expanding. Transformation between semiarid and arid zones, humid and semihumid zones is frequent. During 2011–2050, annual precipitation will not change much (−6~12%) except river basins in the southwest (more than 40%) compared with the baseline. Besides, the area of arid zone will decrease and humid zone area will increase. Transformation area between semiarid and arid zone and humid and semihumid zone is small.
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Raimundo Mainar de Medeiros, Luciano Marcelo Fallé Saboya, Manoel Viera de França, Romildo Morant de Holanda, Victor Casimiro Piscoya, Alex de Sousa Moraes, Wagner Rodolfo de Araújo, and Moacyr Cunha Filho. "Methodological procedures, analysis of the aridity, desertification and semi-arid index for the municipality of Santa Filomena, Piauí, Brazil." International Journal of Science and Research Archive 7, no. 1 (October 30, 2022): 323–419. http://dx.doi.org/10.30574/ijsra.2022.7.1.0211.
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The municipality Santa Filomena that it was for is included in the Nucleus of Desertification of Gilbués, since all the other municipalities that are part of the same nucleus are. Data from the IBGE Demographic Census (2010) and the GDP of the municipalities published by IBGE (2009) were used. Social indicators of exclusion of education and income are sought. In addition to being reduced, GDP is far from ideal for a good quality of life. All the social indicators of the semiarid region are very bad. The evidence of the study allows us to conclude that, in fact, in this region, in relative terms, numbers are concentrated that allow the inclusion of these municipalities in the semi-arid area. In addition, the justifications for additional criteria because these municipalities belong to the Nucleus of Desertification of Gilbués, being the only one not yet contemplated with its inclusion in front of all the others already included, including those that belong to the other three nuclei existing in Brazil. The study of the aridity index and its tendency to desertification for the municipalities of Santa Filomena, Barreiras do Piauí, Gilbués and Monte Alegre do Piauí, Brazil was requested by a group of farmers, mayors and lawyers who intend to see the possibility of including these municipalities as a degraded area and its inclusions in the Brazilian semiarid region. The methodology used the calculations of aridity indexes by the water balance method developed by Thornthwaite and Mather (1948; 1955) with a field capacity (CAD) of 100 mm. The water balance graphs were used to demonstrate the variability of water surpluses and deficiencies, replacement and removal of water in the soil and visualization of interannual buoyancy. Electronic spreadsheets of evapotranspiration, evaporation, deficiency and annual water surplus were generated in order to understand their interannual fluctuations as an aid in erosive contributions and aridity indexes. The monthly rainfall for the period 1960-2017 was acquired from the climate bank of Superintendence for the development of the Northeast and from the Empresa de extensión Rural do Piauí where annual fluctuations, anomalies, moving averages, standard deviation, coefficient of variance, absolute maximums and minimums, in addition to studying the fluctuation of average temperatures and calculations of precipitation erosivity indices for the referred municipalities aiming at the objective of municipalities to be included in the semi-arid region and susceptible to desertification. The physiographic aspects, relief, fauna, flora and distance from the sea are evidenced and the edaphic contributions contribute to the incidence of aridity index and susceptibility to desertification in the studied area. The development of monoculture and improper planting techniques contributed to the increase in erosion rates and the tendency for changes in the semi-arid climate with very high risk of susceptibility. Areas identified as vulnerable to desertification, due to the lower aridity index, may not be located in the degraded area, and areas that present a higher aridity index and are not identified as vulnerability processes may be degraded to the point of being considered desertified areas. This variability may occur due to inappropriate use of the soil and environment. Temperature influences evapotranspiration, that is, the loss of water to the atmosphere, because the higher the temperature, the greater the evapotranspiration and, consequently, the lower the aridity index and, therefore, the greater the susceptibility to desertification. Possibly anthropic factors, the lack of afforestation in the beds of ponds, lakes, rivers, streams, streams, dams and water tables, the vertical construction and compaction of urban and rural soil plus transient meteorological systems and local factors may have contributed to periods ( months, years) with greater variability, however it is known that depending on the season, summer or winter, evapotranspiration and evaporation can really vary, as they are directly related to the seasons with higher and lower precipitation, variability in air temperature, air humidity between other variables such as solar radiation, cloud cover, wind speed and vapor saturation pressure, which can reduce the evaporative process.
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Silva, Viviane Farias, Dihego Souza Pessoa, Thalis Leandro Bezerra Lima, Ana Maria Ferreira Cosme, and Vera Lucia Antunes Lima. "Analysis of water quality in the watershed Brazilian semiarid." Ciência e Natura 40 (December 7, 2018): 69. http://dx.doi.org/10.5902/2179460x32055.
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Water is a renewable natural resource, important for maintenance of life on the entire planet. Even with this significance is a feature that has been degraded and reduced the quality to use. In the Brazilian semi-arid region water scarcity by influencing the quality of life of the population, directly affecting the socio-economic and development means. In this context, the present research was conducted aiming to evaluate the water quality in the watershed Brazilian semiarid. The survey was conducted in three watersheds (Capibaribe river, Ipojuca river and Igarassu river) in the State of Pernambuco, Brazil. Water Quality Index (WQI) and Biochemical Oxygen Demand (BOD) annual averages of the year 2006 to 2015. In Capibaribe river watershed the largest concentrations of BOD occurred in 213, 2014 and 2015, with average was 4.95 mg/L. By increasing the BOD value there is a reduction of WQI. The Igarassu river, it was verified that from 2006 to 2014 the hydrographic basin has water quality classified as good. The BOD in the waters of the Ipojuca river has little influence on the water quality index.There is a degradation on the quality of water of basins due mainly to anthropic pollution.
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Medeiros, AMA, JEL Barbosa, PR Medeiros, RM Rocha, and LF Silva. "Salinity and freshwater discharge determine rotifer distribution at the Mossoró River Estuary (Semiarid Region of Brazil)." Brazilian Journal of Biology 70, no. 3 (August 2010): 551–57. http://dx.doi.org/10.1590/s1519-69842010000300011.
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The present study aimed at evaluating differences in rotifer distribution in three estuarine zones in an inverse estuary located in the Semiarid Region of Brazil. Zones were chosen based on their proximity to the ocean and river border as a means of reflecting a horizontal salinity gradient. High freshwater discharge during the rainy season was the major determinant of rotifer composition. On the other hand, due to higher salinity values during the dry season, very low values of species richness and abundance were observed in all zones. Therefore, the study highlights the constraints of salinity and the positive influence of seasonality and river proximity on rotifer species in a semiarid estuarine environment.
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Leão, Raimundo A. de O., Antônio A. Soares, Adunias dos S. Teixeira, and Demetrius D. da Silva. "Georeferenced database generation with the purpose of hydrologic molding in reservoirs of the hydrographic basin of Jaguaribe river in the state of Ceará, Brazil." Engenharia Agrícola 33, no. 2 (April 2013): 388–401. http://dx.doi.org/10.1590/s0100-69162013000200017.
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The edafoclimatic conditions of the Brazilian semiarid region favor the water loss by surface runoff. The state of Ceará, almost completely covered by semiarid, has developed public policies for the construction of dams in order to attend the varied water demand. Several hydrological models were developed to support decisive processes in the complex management of reservoirs. This study aimed to establish a methodology for obtaining a georeferenced database suitable for use as input data in hydrological modeling in the semiarid of Ceará. It was used images of Landsat satellite and SRTM Mission, and soil maps of the state of Ceará. The Landsat images allowed the determination of the land cover and the SRTM Mission images, the automatic delineation of hydrographic basins. The soil type was obtained through the soil map. The database was obtained for Jaguaribe River hydrographic basin, in the state of Ceará, and is applicable to hydrological modeling based on the Curve Number method for estimating the surface runoff.
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Xu, Zhonglin, Zhaodong Feng, Chuanyan Zhao, Jianghua Zheng, Jianjun Yang, Fengxia Tian, Huanhua Peng, Chao Wang, Shouzhang Peng, and Hassan Sher. "The canopy rainfall interception in actual and potential distribution of Qinghai spruce (Picea crassifolia) forest." Journal of Hydrology and Hydromechanics 61, no. 1 (March 1, 2013): 64–72. http://dx.doi.org/10.2478/johh-2013-0008.
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Abstract Interception is one of the most underestimated processes in hydrological cycle in arid and semiarid regions. In Qilian Mountains of northwestern arid and semiarid China, the Qinghai spruce (Picea crassifolia) forest plays an important role in the hydrological cycle of the inland Heihe River basin. The historical disturbance of Qinghai spruce forest has resulted in various ecological problems. In order to realize the sustainable development of Heihe River basin, the Chinese government implemented restoration practices for Qinghai spruce in the past three decades. In this study, we estimated the rainfall interception in the actual and potential distribution of Qinghai spruce forest. Some of the important findings include: (1) The interception ratio of rainfall events ranged from 11-51% with a mean value of 27.02%; (2) Totally, 147 Mt of rainfall is intercepted by canopy of actual Qinghai spruce forest, in the projected potential distribution of the forest, totally 407 Mt of rainfall will be intercepted.
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Lira, Daniel Rodrigues de. "MUDANÇAS AMBIENTAIS QUATERNÁRIAS NA PORÇÃO SUBMÉDIA DA PLANÍCIE DO SÃO FRANCISCO: RECONSTRUÇÃO AMBIENTAL." CLIO – Arqueológica 32, no. 3 (September 5, 2017): 107. http://dx.doi.org/10.20891/clio.v32n3p107-134.
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A dinâmica dos acontecimentos geomorfológicos e sua evolução tornam-se necessárias para elucidar a história recente da paisagem. Nessa perspectiva a análise de depósitos superficiais permitiu a reconstrução das dinâmicas ambientais para a região com ênfase temporal/paleoambiental. Os Latossolos que integram a Planície do Rio São Francisco têm origem a partir do rebaixamento de suas águas e surgimento de barras arenosas retrabalhadas pelo vento em períodos de maior semiaridez formando campos de dunas; em períodos mais úmidos, mantos de areia, sendo estes retrabalhados em momentos de cheias, originando depósitos arenosos na planície fluvial. Os estudos indicam uma gênese climática controlada por fatores da circulação geral da atmosfera em nível global e regional, revelando tele conexões importantes desde o Último Máximo Glacial – UMG, transição Pleistoceno/Holoceno até o Holoceno Superior. QUATERNARY ENVIRONMENTAL CHANGES IN THE SUBMIDDLE REACH OF SÃO FRANCISCO RIVER FLOODPLAINS: AN ENVIRONMENTAL RECONSTRUCTION ABSTRACTThe analysis of superficial deposits allows the reconstruction the environmental dynamics of the study area within a given palaeo-environmental time frame. The Oxisols developed on the Sao Francisco floodplain deposits, originate from the lowering of water-table levels in the river banks and the subsequent emergence of sandy bars, some of which were reworked by wind erosion during periods of stronger semi-aridity, resulting in the accumulation of dune fields and sand mantles in wetter periods. Later on, some of these deposits were reworked by the floods of the São Francisco River. The results of this research point to a climatic genesis of landforms, driven by general circulation controls, thus revealing the role of important atmospheric teleconnection events in the area occurring since the Last Glacial Maximum – LGM, through the Pleistocene/Holocene transition until the Upper Holocene.Keywords: evolution of the landscape; superficial deposits; semiarid.
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Makunina, N. I. "Mountain forest-steppe of South-East Altai and South-West Tuva." Vegetation of Russia, no. 24 (2014): 86–100. http://dx.doi.org/10.31111/vegrus/2014.24.86.
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Some geobotanists, who studied arid mountain steppe landscapes in South-East Altai and South-West Tuva, mentioned the existing of small isolated larch forest areas at the height 2100–2400 m above sea level (Kuminova, 1960; Il’inskaya, 1980). We have made a special investigation of the vegetation of this rather peculiar forest-steppe. It can be called “high-mountain forest-steppe” by the altitudinal position and “cold forest-steppe” by the level of the heat. Such forest-steppe areas are found only in certain orographic conditions: they are confined to the slopes of rivers’ valleys. The foots of these slopes are situated at an altitude 1900–2000 m a. s. l. and the flat tops of the mountains – at 2400–2500 m a. s. l. Light slopes of the mountains are occupied by bunchgrass steppes, larch forests and meadow steppes are located on the shady slopes. Forest-steppe landscapesare confined to thealtitudinal rangeof the steppe belt, whichis divided intotwosubbelts: the lower with bunchgrass(moderately dry) steppes and theupper with cryophytic steppes. The boundaries betweensub-belts are at differentaltitudes in the SoutheastAltai andSouthwestTuva. In South-Eastern Altai bunchgrasssteppes are replaced by cryophytic ones at the height 2400–2500m a. s. l., so forest-steppes are completely included in bunchgrass steppe subbelt. In SouthwesternTuva this boundary is at 2200–2300 m a. s. l., so the lower parts of the light slopes are covered by bunchgrass steppes and the upper parts — by cryophytic steppes. The steppes in mountain forest-steppe of South-East Altai belong to alliance Helictotrichion schelliani, the Tuvinian ones — to alliance Festucion tschujensis. These two alliances are from order Helictotrichetalia shelliani, class Cleistogenetea squarrosae.Alliance Helictotrichion schelliani includes mountain steppes that mostly occur in semiarid bioclimatic regions of South Siberia and North Mongolia; forest-steppe plant communities of arid South-East Altai represent the “cold branch” of this alliance. The bunchgrass steppes belong to new association Potentillo sericeae–Agropyretum cristati,the meadow steppes — to new association Sileno repentis–Caricetum pediformis. In mountain forest-steppe of South-West Tuva 3 associations present alliance Festucion tschujensis which combines steppe communities with participation of cryopetrophytic species. Bunchgrass steppes are described as new association Oxytropido macrosemae–Agropyretum cristatae, cryophitic steppes – as new association Oxytropido eriocarpae–Poetum attenuatae, meadow steppes are included in association Artemisio phaeolepidis–Kobresietum myosuroidis. The larch forests belong to alliance Pachypleuro alpini–Laricion sibiricae (order Festuco ovinae–Laricetalia sibiricae, class Rhytidio rugosi–Laricetea sibiricae). Forests of association Swertio obtusae–Laricetum sibiricae are characteristic of South-East Altai, forests of association Artemisio rupestris–Laricetum sibiricae are common in South-West Tuva, forests of association Kobresio myosuroides–Laricetum sibiricae are recorded in both regions.
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Silva, Jhon Lennon Bezerra da, Geber Barbosa De Albuquerque Moura, Marcos Vinícios Da Silva, Roni Valter De Souza Guedes, Pabrício Marcos Oliveira Lopes, Ênio Farias de França e Silva, Rochele Sheila Vasconcelos, and Anna Hozana Francilino. "Inferência Exploratória de Dados Espaço-Temporal da Precipitação Pluviométrica no Nordeste Brasileiro." Revista Brasileira de Geografia Física 13, no. 5 (July 29, 2020): 2019. http://dx.doi.org/10.26848/rbgf.v13.5.p2019-2036.
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A gestão eficiente dos recursos hídricos no Nordeste brasileiro torna-se fundamental diante do regime hidrológico dos rios intermitentes, dos quais muitos são extremamente críticos. Todavia estes dependem de um regime pluviométrico irregular, tanto em escala de tempo mensal quanto anual. Objetivou-se determinar a variabilidade espaço-temporal da precipitação pluviométrica total anual, averiguando-se, também, as regiões com padrões de precipitação semelhantes por técnicas de análise multivariada (clusters e componentes principais) no Nordeste do Brasil. Foram analisados dados de precipitação pluviométrica total anual, entre os anos de 1995 e 2016, de 37 diferentes estações meteorológicas do INMET, estas situadas nos limites territoriais dos nove estados do Nordeste brasileiro. A análise de clusters verificou a formação de quatro grupos distintos, com padrões semelhantes de precipitação nas regiões dentro dos grupos, conforme também observado na análise de componentes principais. A padronização e/ou variabilidade espaço-temporal da precipitação pluviométrica dos municípios analisados mostrou-se está intimamente associada as condições das estações do ano e anomalias climatológicas, aos fatores de uso e ocupação do solo, condições de altitude e relevo, tais quais favorecem na formação e estabilidade de chuvas menores ou maiores no Nordeste brasileiro. A análise multivariada de cluster e componentes principal identificaram padrões e semelhanças pluviométricas de grupos, nos diferentes estados do Nordeste do Brasil entre os anos de 1995 e 2016. Exploratory Inference of Spatial-Temporal Data of Rainfall in the Brazilian Northeast ABSTRACTThe efficient management of water resources in the Northeast of Brazil is essential in view of the hydrological regime of intermittent rivers, of which many are extremely critical, as they depend on an irregular rainfall regime, both on a monthly and annual time scale. The objective of this study was to determine the spatial and temporal variability of the annual total rainfall, also investigating the regions with similar rainfall patterns by multivariate analysis techniques (clusters and principal components) in Brazilian Northeast. Data from total annual rainfall between the years 1995 and 2016, of 37 different INMET weather stations were analyzed, located within the territorial limit of the nine states of Brazilian Northeast. Cluster analysis verified the formation of four distinct groups, with similar precipitation patterns in the regions within the groups as also observed in the principal component analysis. The pattern and/or spatial-temporal variability of rainfall in the municipalities analyzed was shown to be intimately associated with the conditions of the year and climatic anomalies stations, and the factors of land use and occupation, altitude and relief conditions, such as favoring the formation and stability of minor or major rain in the Brazilian Northeast. Multivariate cluster and principal component analysis identified rainfall patterns and similarities of groups, in the different states of Northeastern Brazil between the years 1995 and 2016.Keywords: multivariate analysis, climate change, semiarid, regional climate patterns.
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Vieira, Priscila R., Fernando F. Pruski, and José R. C. Souza. "Dimensioning of reservoirs for semiarid regions using synthetic series." Revista Brasileira de Engenharia Agrícola e Ambiental 24, no. 9 (September 2020): 581–89. http://dx.doi.org/10.1590/1807-1929/agriambi.v24n9p581-589.
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ABSTRACT The lack of fluviometric data for hydrographic basins affects the estimates of capacity of regularization reservoirs, important to meet water seasonal demands. The objective of this study was to evaluate the performance of methodologies based on synthetic series (SS) of streamflow for the dimensioning of regularization reservoirs in the Jequitinhonha River Basin, Brazil. The reservoir capacity (RC) was estimated with and without the association to return period, using different long-term mean streamflow rates, SS from the observed data, and estimated data by the streamflow regionalization process developed by the Instituto Mineiro de Gestão das Águas. The results obtained were compared to the RC obtained in regionalization methods of the regularization curve and regionalization of reservoir capacity. The methods that include synthetic series associated to return period presented better performance, with 25% and 15% lower overestimate and underestimate means, respectively, and estimated values closer to those that considered the observed data series. Therefore, the use of methodologies to estimate RC, using SS was adequate for the locations without fluviometric monitoring in the Jequitinhonha River Basin.
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Silva, Camilo Vinícius Trindade, Eunice Maia de Andrade, Luis Cesar de Aquino Lemos Filho, Jacques Carvalho Ribeiro Filho, and Hermínio Sabino de Oliveira Júnior. "Temporal dynamics of soil susceptibility to erosion in semiarid watersheds." Acta Scientiarum. Agronomy 43 (March 18, 2021): e51378. http://dx.doi.org/10.4025/actasciagron.v43i1.51378.
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The intensification of anthropogenic activities on soils contributes to soil loss through erosion. Moreover, the pattern of soil loss in the Cobra River watershed, located in the semiarid region of Rio Grande do Norte, is related to the history of land use and occupation, mainly from agriculture and the red ceramic industry, as well as the climatic seasonality of the region. Thus, the objective of this work was to identify the pattern of soil loss from the Cobra River microbasin in the state of Rio Grande do Norte. For this, the following analyses were performed: a survey of land use class areas for the years 1987, 1997, 2007 and 2017 as part of the Mapbiomas project; estimation of basin soil loss for these years; and quantification of areas of erosion vulnerability classes for this period. QGIS software was used to treat georeferenced data. According to the results, the land cover classes in the rich Cobra River microbasin fluctuated over time. Potential soil loss from the watershed increased from 1987 to 2017, with an increase of approximately 20 million megagrams of potentially erodible soil. The study of soil loss in a microbasin located in the Brazilian semiarid region should consider the variation in land cover over time, climatic seasonality and anthropic activity. To this end, it is important to use geotechnology and geoprocessing techniques to conduct a more robust spatiotemporal analysis.
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Lu, Yuming, Bingfang Wu, Nana Yan, Weiwei Zhu, Hongwei Zeng, and Linjiang Wang. "Method for Environmental Flows Regulation and Early Warning with Remote Sensing and Land Cover Data." Land 10, no. 11 (November 10, 2021): 1216. http://dx.doi.org/10.3390/land10111216.
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Environmental flows play a vital role in ecosystem and water resource management. The regulation and management of environmental flows can improve the function and stability of river and lake ecosystems. However, current methods for assessing environmental flows mainly emphasize water management, and there is no complete set of regulations or early warning systems, especially in arid and semiarid basins. In this study, we proposed a method for environmental flows regulation and early warning with remote sensing and land cover data and carried out a case study in the Yongding River Basin, which is a basin typical of arid and semiarid areas. The results show that from 2001 to 2014 the mean precipitation was 17.90 × 109 m3, and the mean water consumption was 19.42 × 109 m3, indicating that the basin water budget was clearly unbalanced and that there was an overall deficiency. Notably, from 2005 to 2014 and in 2014, the available consumable water was less than the water consumption required for human activities, which both showed a trend of further reduction; therefore, long-term and annual early warnings should have been issued. The methods applied in this study and the study outcomes could help in the development of comprehensive management and ecological restoration plans, further improving the ecological environments of river basins.
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Jones, Erin Fleming, Rebecca J. Frei, Raymond M. Lee, Jordan D. Maxwell, Rhetta Shoemaker, Andrew P. Follett, Gabriella M. Lawson, et al. "Citizen science reveals unexpected solute patterns in semiarid river networks." PLOS ONE 16, no. 8 (August 19, 2021): e0255411. http://dx.doi.org/10.1371/journal.pone.0255411.
Full textAbstract:
Human modification of water and nutrient flows has resulted in widespread degradation of aquatic ecosystems. The resulting global water crisis causes millions of deaths and trillions of USD in economic damages annually. Semiarid regions have been disproportionately affected because of high relative water demand and pollution. Many proven water management strategies are not fully implemented, partially because of a lack of public engagement with freshwater ecosystems. In this context, we organized a large citizen science initiative to quantify nutrient status and cultivate connection in the semiarid watershed of Utah Lake (USA). Working with community members, we collected samples from ~200 locations throughout the 7,640 km2 watershed on a single day in the spring, summer, and fall of 2018. We calculated ecohydrological metrics for nutrients, major ions, and carbon. For most solutes, concentration and leverage (influence on flux) were highest in lowland reaches draining directly to the lake, coincident with urban and agricultural sources. Solute sources were relatively persistent through time for most parameters despite substantial hydrological variation. Carbon, nitrogen, and phosphorus species showed critical source area behavior, with 10–17% of the sites accounting for most of the flux. Unlike temperate watersheds, where spatial variability often decreases with watershed size, longitudinal variability showed an hourglass shape: high variability among headwaters, low variability in mid-order reaches, and high variability in tailwaters. This unexpected pattern was attributable to the distribution of human activity and hydrological complexity associated with return flows, losing river reaches, and diversions in the tailwaters. We conclude that participatory science has great potential to reveal ecohydrological patterns and rehabilitate individual and community relationships with local ecosystems. In this way, such projects represent an opportunity to both understand and improve water quality in diverse socioecological contexts.