Regular Flooding Research Articles

Mobile outreach clinics for improving health care services accessibility in vulnerable populations of the Diffa Region in Niger: a descriptive study.

Niger is a large country with many distant locations that can be difficult to access because the Sahara Desert covers 80% of the country's land. In Niger, just 49% of residents have access to a health centre within 5km of their house. Health care may be difficult to access in the Diffa region of Niger, as non-state armed groups strike on a regular basis and floods cause a high rate of vulnerability. This study looked at how mobile clinics can improve healthcare accessibility for vulnerable populations in the Diffa region. This was a descriptive-comparative study conducted over the period from 15 August 2022 to 15 October 2022, using three months' mobile outreach clinic to improve health outcomes in five districts of the Diffa region, including Bosso, Diffa, Goudoumaria, Mainé Soroa, and N'guigmi. During the three months of mobile outreach clinic, 42,251 people were sensitized about mobile outreaches and 12,004 were treated. A total of 18,708 vaccine doses were delivered to children aged 0-11months, with Maine Soroa, Goudoumaria, Bosso, Diffa, and N'guigmi districts accounting for 29.24%, 24.62%, 18.54%, 18.05%, and 9.5%, respectively. In the same line, Goudoumaria, Bosso, and Maine Soroa districts recorded relatively high antenatal clinic (ANC) attendance percentages of 27.85%, 25.62%, and 21.89%, respectively. Furthermore, mobile clinic outreach provided a variety of healthcare treatments, both curative and preventative. Mobile Clinic 2 increased vaccine dose received among children aged 0-11months by 1.11% (95%CI: 0.15%-2.06%, P = 0.023) when compared to Mobile Clinic 1. In the same line, mobile clinic showed a statistically significant increase of ANC between the three clinical rotations (P = 0001), showing an increased ANC update over time. This study found that mobile outreach clinic can play an important role in improving healthcare access for vulnerable populations in the Diffa region. However, well-designed, and frequent mobile clinic outreach should be planned and included in the country's public health policy.

In-situ water retention monitoring system of an operational dike

The severe droughts in recent decades and the lack of regular flooding have caused considerable fissures to develop on clay embankments. Previous surveys in Hungary have identified the examined dike section as prone to desiccation cracks. It is essential to determine the possible extent of these desiccation cracks, as they degrade the dikes’ resistance against several failure mechanisms. A representative dike cross-section was equipped with a unique water retention monitoring system comprising 17 sensors, including 14 soil moisture and 3 water potential sensors. These devices were validated with laboratory measurements to obtain accurate results. The gravimetric water content (w) ranged from 8.3 % to 31.3 %, and the matric potential was recorded between 0.1 kPa and 2350.7 kPa over one and a half years. The study examined the differences in soil behaviour under pavement and turf cover, identifying common moisture content distribution patterns and areas of the cross-section prone to desiccation cracking. The uniqueness of the monitoring system lies in the fact that it was established in an operational embankment, which regulates the flow of a river. Furthermore, it was instrumented along the Tisza River, which is among Europe’s most significant watercourses. The results may help better understand the moisture content change in clay embankments and the role of the crest pavement in the moisture content distribution.

High δ 15N and δ 13C Values in Aurochs, Cattle and Sheep Bones from Salt Marshes in the North of The Netherlands

ABSTRACT 185 pairs of δ 13C and δ 15N values for aurochs, cattle and sheep bones from the northern Netherlands were studied to establish the influence of salt marsh grazing on bone δ 13C and δ 15N values. The observed values proved significantly increased compared to livestock that grazed inland. The δ 13C and δ 15N values of animals grazing former salt marshes were significantly less increased than those grazing the unembanked salt marsh. Absent regular salt marsh flooding may explain the reduced δ 13C increase in bones of animals grazing there. The δ 15N values of ruminants grazing the embanked salt marshes continued to be increased, presumably due to persisting saline water at shallow depths. The δ 13C values of the salt marsh grazing ruminants correspond with a δ 13C increase of 5‰ compared to eleven modern salt marsh plants from Schiermonnikoog studied in this paper. The δ 15N values of the eleven Schiermonnikoog salt marsh plants proved variable, on average too low to explain the observed 3.5‰ increase in δ 15N values. This suggests that vegetation δ 15N values cannot be the only cause of the high δ 15N values observed in salt marsh ruminants. Other processes may be responsible for the high δ 15N values of salt marsh grazing ruminants as well.

Flood sediments as a source of replenishment of alluvial soils with plant nutrition elements

Flood sedimentation in conditions of regular floodplain flooding is a key factor in the formation of alluvial soil. The nature of the passage of hollow waters and their composition affect the quantitative and qualitative characteristics of flood sediments, while having a significant impact on the agroecological state of the floodplain agricultural landscape. The aim of the research was to study the role of flood sediments in enriching the underlying alluvial soil with nutrients. The experiment was conducted on reclaimed arable lands of the Ryazan region in 2023. Determination of the sediment load level and sampling on the surface were carried out using plastic sedimentation samplers fixed on the soil surface, located at a distance of 200 m from each other. The installation was carried out on March 23, the duration of sediment collection was 42 days before the descent of the hollow waters. The average sediment load level of 15.4 t/ha was established, the agrochemical properties of flood sediments and underlying soil were studied, the structure of organic matter, macro– and microelements with flood sediments and their removal from the corn harvest to silage was analyzed. Together with sediments the soil received (kg/ha): total nitrogen – 107.80, total phosphorus – 43.10, total potassium – 104.70, organic matter – 2464,0, mobile phosphorus 15.20, exchangeable potassium 17.80; trace elements (g/ha): boron – 11.86, molybdenum – 1.54, zinc – 122.74, manganese – 1215.06, copper – 200.20, cobalt – 52.05. With a corn harvest for silage of 36.1 kg/ha, the takeaway was: N – 105 kg/ha, P2O5 – 33 kg/ha, K2O – 105 kg/ha. The conducted studies indicate the undoubted agronomic value of flood sediments, they can partially meet the need for fertilizers, therefore, it is necessary to take into account the mass of the substances used to carry out appropriate adjustments to the fertilizer application system. In 2023, the mass of incoming substances with flood sediments completely covered the need for nitrogen; for mobile phosphorus the need decreased to 17.8 kg/ha, for exchangeable potassium the need decreased to 87.2 kg/ha.

Small stream floodplains have high conservation value for riparian carabid beetles but less for ground‐dwelling spiders

Abstract Floodplains along rivers and streams are characterised by a high habitat heterogeneity and a large biodiversity. However, floodplains are highly threatened by anthropogenic activities such as channelisation and bank enforcement of watercourses. While floodplains along rivers are well known for their importance for riparian biodiversity, the conservation value of floodplains along small streams is less understood. We studied carabid beetles (Coleoptera: Carabidae) and ground‐dwelling spiders (Arachnida: Aranea) along forested small streams (~ up to 5 m width) in Rhineland‐Palatinate (Germany). We investigated 16 pairs of floodplains (natural stream sites with shallow bank and regular flooding events) and controls (deeply cut stream sites without regular flooding), where we sampled carabid beetles and spiders at different distances to the stream bank (0, 5 and 10 m). We found that floodplains along small streams had contrasting value for carabid beetles and ground‐dwelling spiders. For carabid beetles, we observed several typical floodplain species and distinct species assemblages and 2.7 times more individuals across species of conservation concern in floodplain sites. Moreover, species richness and total number of individuals of carabid beetles were highest directly at the stream bank (0 m distance) of floodplains compared with the more distant locations, while the opposite was found for the control stream sites. The spider composition also differed between floodplains and control steam sites, but only one typical floodplain species was detected. Species richness and number of individuals in ground‐dwelling spiders were lower in floodplains than in control stream sites. We conclude that the conservation value of floodplains of small streams is taxa‐dependent and that they appear less relevant for ground‐dwelling spiders but provide important habitats for riparian carabid beetles.

Investigating the Impact of Recent and Future Urbanization on Flooding in an Indian River Catchment

Socioeconomic growth in India has caused massive infrastructure development which has resulted in extensive damage to the natural environment. A consequence of this urbanization has been extensive monsoon flooding in many locations within the country. The impact of recent land use and land cover (LULC) change because of urbanization and a series of future LULC scenarios is assessed for the Meenachil river basin in central Kerala, India. This catchment flows into the Kuttanad administrative area, which has the country’s lowest elevation, an increasing population, and currently suffers from regular flooding. Hydrological modeling using SHETRAN and hydraulic modeling using HEC-RAS predicts that an extreme event will produce a 105% rise in flood depth in 2100 compared to 2005. A scenario that incorporates Nature-based Solutions suggests the rise in flood depth could be reduced by 44%. A catchment response for future development is needed but is hindered by different administrative boundaries within the river basins that flow into the Kuttanad administrative area, and so this study concludes by providing regional-scale planning recommendations that integrate hydrologic components.

Is it the people or the place? The remarkable 30-year period of integrative physiology research in the Carlson Gymnasium at the University of Colorado Boulder.

Historically, programs of physical education and sport were housed in gymnasium buildings on academic campuses. As physical education evolved to the more scientifically focused successor departments of exercise science and kinesiology, faculty specialization developed in the physiology of exercise. With time, some faculty broadened their research to study the integrative physiology of other biological states and stressors. Through this series of events, a small group of integrative physiologists was formed in the Carlson Gymnasium at the University of Colorado Boulder during the 1990s with the goal of conducting novel biomedical research. The challenges were daunting: no contemporary core laboratory facilities, lack of temperature control, piercing external noise, pests, regular flooding, electrical power outages, and lack of funds for renovation. Despite these obstacles, the group established an innovative program of translational physiological research ranging from high-throughput molecular analyses to cell models to rodent studies to clinical trials in humans. These investigators supported their work with grant awards from the National Institutes of Health (NIH), Department of Defense, National Aeronautics and Space Administration (NASA), American Heart Association, and private research foundations totaling ∼$80 M in direct costs from the late 1980s to 2020. Collectively, the faculty and their laboratory personnel published ∼950 articles in peer-reviewed scientific journals. Over that period, 379 undergraduate students, 340 graduate students, 84 postdoctoral fellows, and dozens of junior research faculty received scientific training in Carlson, supported by >$21 M in extramural funding. What was accomplished by this handful of integrative physiologists speaks to the importance of the qualities of the investigators rather than their research facilities in determining scientific success.

Estoque de Carbono em Marismas

Salt marshes are typical of temperate climate regions that border estuarine margins, covering intertidal areas subject to regular or irregular flooding. Among the many benefits they provide to the ecosystem, their remarkable ability to sequester carbon from the atmosphere and store it in their substrate for periods ranging from centuries to millennia is particularly noteworthy. This carbon, retained in the form of CO2 in coastal and estuarine environments by salt marshes, is known as "blue carbon." This study aimed to investigate the current state of knowledge about carbon stocks in salt marshes through a systematic bibliographic approach. Three databases were selected for the research: Springer, ScienceDirect, and Periódicos Capes. In each of them, the keywords "tidal salt marsh" and "carbon stock" were used, employing quotation marks around each term and the AND operator. It was observed that, given the urgency to develop actions to mitigate the effects of climate change, studies focusing on salt marshes have received increasing attention globally. However, this interest is recent, and knowledge on the subject is still limited, focusing on specific regions of the planet. The complexity of these habitats is a frequently neglected topic, although of great importance. Invasive plants have an impact on the dynamics of the carbon cycle in these areas. Additionally, the heterogeneity of salt marshes is a crucial factor to be considered in studies to avoid errors in carbon inventories. Salt marsh restoration activities are considered appropriate approaches to coastal management, potentially transforming degraded areas into carbon sinks.

Macroscale Modeling of Geochemistry Influence on Polymer and Low-Salinity Waterflooding in Carbonate Oil Reservoirs.

The enhancement of oil recovery (EOR) through low-salinity waterflooding (LSWF) and the emerging hybrid with a polymer (LSP) has proven to be effective at microscale investigations and cost-effective with ease of operation at field-scale tests. Their application in carbonate oil reservoirs, which typically occur oil-wet, presents a particularly essential capacity given that over half of the global oil reserves are hosted in carbonate formation. However, modeling the mechanisms involved to predict and evaluate the performance of low salinity-based EOR at a large scale is complex and requires the integration of geochemistry in reservoir simulation to upscale the interfacial interactions of crude oil, brine, and rock observed at the micrometer scale. This study presents an integrated approach that combines MRST's polymer model with PHREEQC geochemical modeling to simulate LSWF at the reservoir scale. Using single-phase and multiphase experimental flooding data for validation, the coupled model was shown to accurately predict effluent ionic and oil recovery profiles. The simulation of LSWF and LSP both exhibited additional tertiary oil recovery, with LSWF and LSP showing 3 and 2%, respectively, which are consistent with previously reported field and core flooding results. Furthermore, the sequential application of formation water (FW), LSWF, and LSP flooding in secondary mode showed a high increase in oil recovery, with oil recovery percentages of 61, 20, and 19%, respectively. However, the FW results were 50% lower compared to regular core flooding due to upscaling limitations. The modeling of vertical and anisotropic permeability heterogeneity effects showed a positive synergy with low-salinity floodings, resulting in a 4% drop and 3 and 1% increase in FW, LSWF, and LSP, respectively. These findings demonstrate the potential of the coupled MRST-PHREEQC model in accurately simulating hydrogeochemical interactions during LSWF/LSP at the reservoir scale, providing valuable insights for the optimization of low salinity-based EOR strategies in carbonate reservoirs.

Introducing the halophyte Salicornia europaea to investigate combined impact of salt and tidal submergence conditions.

Tolerance mechanisms to single abiotic stress events are being investigated in different plant species, but how plants deal with multiple stress factors occurring simultaneously is still poorly understood. Here, we introduce Salicornia europaea as a species with an extraordinary tolerance level to both flooding and high salt concentrations. Plants exposed to 0.5MNaCl (mimicking sea water concentrations) grew larger than plants not exposed to salt. Adding more salt reduced growth, but concentrations up to 2.5MNaCl were not lethal. Regular tidal flooding with salt water (0.5MNaCl) did not affect growth or chlorophyll fluorescence, whereas continuous flooding stopped growth while plants survived. Quantitative polymerase chain reaction (qPCR) analysis of plants exposed to 1% oxygen in air revealed induction of selected hypoxia responsive genes, but these genes were not induced during tidal flooding, suggesting that S. europaea did not experience hypoxic stress. Indeed, plants were able to transport oxygen into waterlogged soil. Interestingly, sequential exposure to salt and hypoxic air changed the expression of several but not all genes as compared to their expression upon hypoxia only, demonstrating the potential to use S . europaea to investigate signalling-crosstalk between tolerance reactions to multiple environmental perturbations.

Low Genetic Variability of the Tundra Vole in Lithuania.

The distribution and spread of the tundra vole (Alexandromys oeconomus) in Lithuania have been documented over the last 70 years, but the genetic diversity of the species has not been studied. In this study, we examined A. oeconomus trapped in three sites in northern and western Lithuania using mtDNA sequence analysis of the cytb and control region. The western and northern sites are separated by anthropogenic landscape barriers. The western site is subject to regular spring flooding. Phylogenetic analyses of the studied individuals placed them in the Central European phylogroup, suggesting that Lithuanian A. oeconomus originated from northeastern Poland. In Lithuania, the genetic diversity of A. oeconomus at both mtDNA loci was relatively low (Hd < 0.6, π < 0.002) compared to that found in other European samples (Hd = 0.833-0.958; π = 0.00402-0.01552). Individuals analyzed in Lithuania were genetically different from samples collected in Poland and Northern Europe (ΦST > 0.15, p < 0.05). The genetic divergence between the western and northern samples of A. oeconomus in Lithuania, together with the low genetic variability among the voles studied, provides new insights into the phylogeography of the species and the influence of barriers on the colonization of the country.

Living in the ‘Blue Zone’ of a sea-level rise inundation map: Community perceptions of coastal flooding in King Salmon, California

As sea-level rise (SLR) inundation maps proliferate, it is important to study their politics – both how they are created and how they act upon and shape various lives and places. This paper uses the example of King Salmon, CA – a rural, low-income residential area projected to be one of the most at risk to SLR on the US West Coast – to examine how a community responds to external projections showing SLR risk to their homes and businesses. Through interviews with 17 King Salmon community members and observation of a county-hosted ‘communities at risk’ workshop, we examined the community’s social context, their past experiences with flooding, and their reaction to SLR projection maps including what next steps they would like to see taken. Residents expressed a strong connection to the place, noting that it is one of the few affordable places to live on the coast in California. We found that residents already live with regular flooding during larger tides of the year and have taken steps to adapt. We observed a strong generational component in responses to projection maps with many older respondents believing or hoping that the worst effects from SLR would not come until after they passed away. Residents expressed a lack of faith in government to address flooding concerns both at present and into the future, noting that general maintenance issues have gone unaddressed for decades. Many residents interviewed and observed seemed open or at least resigned to the possibility of relocation at a future undetermined time. This work reveals the power dynamics inherent in climate projections like SLR maps, which, due to their technical nature and mobility, can leave communities out of conversations related to potential futures. Findings also have implications related to climate and SLR work – highlighting the importance of understanding community context; contributing to equity considerations about how wealth and other demographic factors shape how communities interact with SLR planning; and spotlighting the need for sustained learning, engagement, and co-production with communities in the ‘blue zones’ of SLR inundation maps.

Morpho-Physiological and Biochemical Responses of Plectranthus amboinicus to Varying Watering Regimes

Water stress is a detrimental event that adversely impacts crop productivity on a global scale. A study was carried out to examine the impact of fluctuating water stress conditions on Jamaican thyme (Plectranthus amboinicus) plant morpho-physiological and biochemical indices. The treatments were regular watering (RW), drought (DR), flooding (FL), and resumption of regular watering after flooding (DHFL) or after drought (RHDR). The DR and FL treatments significantly (p&lt;0.01) reduced plant fresh weight by 92% and 88%, respectively, compared to RW. The relative water content of DR plants showed a significant (p&lt;0.01) reduction by 60% compared to the RW plants. Net photosynthetic rate, transpiration rate, and stomatal conductance were significantly (p&lt;0.01) reduced in DR and FL plants; whereas sub-stomatal carbon dioxide was significantly (p&lt;0.01) high in DR plants. Chlorophyll a, b, and carotenoids were significantly (p&lt;0.05) reduced in the DR and FL plants compared to the RW plants. On the other hand, soluble sugar content in the DHFL plants was significantly (p&lt;0.05) increased compared to that of the RW plants. FL plants showed a significant (p&lt;0.05) increase in total 2,2-diphenyl-1-picrylhydrazyl scavenging effect by 156%, total flavonoids by 225%, total phenolics by 242%, and malondialdehyde by 94% compared to RW. In conclusion, this study highlighted the morpho-physiological and biochemical changes in Jamaican thyme plants under varied watering regimes. Jamaican thyme is an aroma medicinal plant and thus, further research should assess volatile organic compounds.

Assessment of Climate Risks, Vulnerability of Urban Health Systems, and Individual Adaptation Strategies in the City of N’Djaména (Chad)

Climate variability and change are already having a negative impact on the health of tens of millions of Africans through exposure to sub-optimal temperatures and extreme weather conditions as well as increasing the range and transmission of infectious diseases. This study aims to identify climate risks and the vulnerability of health systems as well as individual coping strategies in the city of N’Djaména. To achieve this, we adopted a methodology combining both quantitative and qualitative approaches. Meteorological data on wind, temperature, and rainfall were collected at daily and monthly intervals from the National Meteorological Agency in N’Djaména. Qualitative data were collected via focus group discussions with targets of the city’s health system and quantitative data were collected from the population on the basis of oriented questionnaires. The results show that rising temperatures with heat waves, regular flooding, and strong winds are the major climate risks identified. These have numerous impacts and effects on the city’s health system due to the following vulnerability factors most recognized by city dwellers: insufficient medical equipment in health facilities (IEME), the fragile nature of people’s physiological state in the face of climatic risks (CFEP), and the failure of city sanitation strategies and policies (DSPA). This study proposes a set of recommendations for transformational adaptation of the healthcare sector, which remains vulnerable to climate risks.

An integrated climate and water resource climate service prototype for long term water allocation in the Upper Yellow River region of China

Water Resourcing in China has historically been a complex issue requiring the ability to deal with regular floods, droughts and diverse water needs. Climate change represents another challenge to this sector, albeit one that is not traditionally considered by water managers. In this sector in China water management is predominantly based on historic, seasonal and annual forecast data while multi-annual and (multi-)decadal data are seldom used. In this paper, we present the co-development of a climate service prototype designed to provide water managers with insights into the impacts of climate change on the Upper Yellow River region for the next century. The paper is an outcome from our project that encouraged water resource planners and water resource managers to utilise long-term climate information to understand the uncertainties and the challenges our changing climate is likely to have in the region. Using an interdisciplinary team and adopting a user-centred, co-production approach, a prototype web-based data visualisation tool was developed. The development of the prototype was based on a design specification constructed from the findings of detailed interviews that allowed it to be developed and tested under SARS-CoV-2 pandemic restrictions that prevented the typical development process to be undertaken. The developed prototype presents climate information and communicates uncertainties regarding climate change in the remainder of the century through data sets that are typically used by the water sector in China in a simple, easy to understand style. Models that estimate river levels under different extraction scenarios and results about estimated river level and flow, and flood risk are also presented. The prototype was shown to be successful, as key messages relating to the impact of climate change and the challenges for water resource management could be effectively communicated through the tool interface. Practical implicationsUnderstanding the impacts of climate change on water resourcing is complicated and multifaceted. There is a need for better data about what water there is and how it is moving around between and within catchments. Estimates of past, present and future climate variables along with historical measurements of river flow can be used to help visualise some of the uncertainties and changes that may happen in the next 50 years. In addition, there is a need to understand changing water demands and water resource management practices. Current water resource management practices are based on historical conditions and assumptions that are less likely to hold true in a more variable and warmer climate. Communicating how future changes will impact future water resourcing is critical to water resources in a changing climate (Belcher et al. 2018).This research outlines the construction of a tool to visualise the impacts of climate change on water availability in part of China that is typically water scarce, using models developed using the Soil Water Assessment Toolkit (SWAT). A model of the Upper Yellow River (UYR) was developed to demonstrate the impact of climate change on river levels in the catchment based on climate variables. The rainfall-runoff model was based on climate predictions from the CMIP5 assessment HadGEM3-GC3.05 climate model and incorporated information about water resource allocations for different administrative regions of the catchment The general climate trend for the region is that it is expected to become significantly warmer. The total amount of precipitation is likely to be about the same, and yet it is expected that overall, the catchment will become significantly drier over time as winter shortens and summer lengthens. The outputs from the model reflect the changes in climate variables. The uncertainties were communicated via a Web based tool. Water resource managers in China helped to coproduce the tool by participating in workshops and providing feedback on prototypes. The workshops helped scientists and water resource managers to communicate about climate change impacts on water resources and water resource management.

Хорологія Spalax arenarius — ендемічного виду гризунів Нижньодніпровських пісків і Таврійського степу

The article analyses one of the most unique species of mammals in the fauna of Ukraine—the fossorial rodent Spalax arenarius. The sandy mole rat is an endemic of the Ukrainian Black Sea region, one of the two endemic species in the mammal fauna of Ukraine and also a species having the smallest geographic range among representatives of the East European mammal fauna. The specifics of the modern distribution of this species, its morphological features and differences from the neighbouring species, from which it can be considered a derivative, are analysed. Particular attention is paid to five aspects of the chorological analysis: 1) description of the current distribution with a detailed map of the species’ occurrence; 2) analysis of ancient Spalax specimens and the former distribution of this species based on actual data; 3) determination of the actual range boundaries, primarily along the land, i.e. in the east of its distribution, 4) analysis of the probable reasons for the range restriction from the west as a probably recent expansion to the region; and 5) construction of a model of the formation of the current range based on re-constructions of the distribution of Spalax in the Taurida Steppe. The latter was carried out considering the morphological features of Spalax arenarius, which are most similar to those of Spalax giganteus, whose modern range is limited to the Caspian Sea regions and, apparently, the North Caucasus. According to morphology and habitat reconstructions, the sandy mole rat is most likely a sister species to Spalax giganteus and one of the source forms for the western S. zemni (similar to the history of ground squirrels). The unique features of the Lower Dnipro population are presented, including the colouration of the feet and rhinaria and the structure of the skull. The history of the Lower Dnipro settlement is considered in view of the regular flooding of the region in historical times (including the flood of 2022). The hypothesis of a recent (possibly secondary) expansion of the species into the region and the specifics of its presence and absence in other neighbouring territories, in particular in the Crimea, Syvash, and the Molochnyi Estuary area, are formulated and considered. The sands zone is most likely the area of recent expansion of the species, which demonstrates a correspondence to the entire complex of Lower Dnipro isolates, including Microtus socialis, Sylvaemus witherbyi, and Scirtopoda telum.

Evaluation of the management potential of timber resources in clearwater floodplain forests in the Amazon using growth models

The Amazonian clearwater igapós are poorly studied floodplain ecosystems that are mainly covered by forests and are undergoing massive threats due to changes in land use and climate. Their hydrochemical characteristics and edaphic conditions fall between those of the eutrophic várzea floodplains on whitewater rivers and those of the oligotrophic igapós on blackwater rivers. Previous studies have indicated the management potential of timber species in the highly dynamic várzea floodplains due to the fast tree growth and high forest productivity. Timber resource management, however, is not recommended for the blackwater ecosystem because of its slow dynamics and high vulnerability to disturbances. For clearwater igapós, information on the potential for sustainable management of timber resources is lacking. In this study, we modeled the growth in diameter, height, and volume to derive species-specific minimum logging diameters (MLD) and felling cycles (FC) for eight merchantable species in the clearwater igapós of the Branco and Tapajós rivers in the northern and southern Amazon Basin, respectively. Diameter growth was modeled by analyzing the tree rings that are annually formed in the Amazonian floodplains as a consequence of the regular and predicable long-term flooding. Growth modeling followed the guidelines of the Growth-Oriented Logging (GOL) concept, with the adjustment of diameter growth improved by applying nonlinear mixed-effects regression. MLDs varied from 36 to 90 cm and FCs ranged from 6 to 21 years, which diverges from the standards of Brazilian logging regulations (MLD: 50 cm; FC: 25–35 years). This indicates the potential for timber resource management, which should be tested and introduced at small scales, integrated in protected areas to stepwise promote the sustainable management of these natural resources by traditional communities to increase their income and the conservation of this ecosystem.

Poetic foundations for watery terrain – three poems below Venice

The Venetian lagoon is a geographical extremity imperilled by extreme weather events. Increasingly regular flooding endangers the lives and livelihoods of Venetians, not to mention the built and natural environments around them. In response to the documentary film Saving Venice (Bulling, 2022), I have produced a short series of poems that address the existential threat that climate change poses to Venice. The first poem refers to the MOSE sea-gates project, a feat of engineering designed to prevent catastrophic flooding of the lagoon. The second takes up the motif of the foundations of Venice, specifically the use of wooden pylons that excise oxygen and moisture and prevent the city from sinking. The third poem deals with the effects of erosion caused by shipping. This poetic work builds upon my previous creative and critical output focussed on Venice as a liminal and literary space, notable for the in-between-ness that comes from being a city built on water (Venzo, 2015; Venzo 2019; Venzo 2022). Extending this scholarship on Venice as a city both real and imagined through writing, these poems represent this watery terrain as simultaneously poetic and ecological (Bryson, 2002). Using the technique of concrete poetry (Draper, 1971; Bray, 2012), each poem syncretises these hidden elements that speak to the effects of extremity, to address the “slipperiness” of this physical environment and construct new foundations in word and image.

Impacts of repeated coastal flooding on soil and groundwater following managed dike realignment

Coastal defense structures (e.g., dikes, seawalls) protect vulnerable communities along marine coastlines and estuaries from the physical and chemical influences of adjacent water bodies. These structures are susceptible to overtopping or breaching by tides and waves, with risks amplified by climate change-induced sea-level rise. Repeated inundation by saline water can contaminate freshwater resources and salinize soil, impacting land-use activities, including agricultural productivity. Managed ecosystem-based dike realignment and salt marsh restoration can provide alternatives to traditional coastal adaptation approaches. We assess the changes to soil salinity at a managed dike realignment project prior to the transformation from a diked terrestrial environment to an estuarine environment. Baseline data are compared to conditions following 8–10 months of intermittent flooding at spring tides.Results show that an increase in salinity occurred over the entire site in the shallow subsurface, with the most significant contamination occurring in low-lying areas. Bulk soil electrical conductivity (salinity proxy) measured from geophysical surveys increased from the previous freshwater condition of ∼300 μS/cm to over 6000 μS/cm following <20 flood events, while successive flooding resulted in increased soil moisture as infiltrated floodwater propagated to greater depths. Sediment deposition occurred at high rates, with up to 4 cm of sediment deposited per flood, converting much of the previously cultivated land into tidal mudflats. Deeper sediments and groundwater (i.e., >1.8 m depth) were not impacted over the time scale of this research. This study demonstrates that intermittent shallow flooding can rapidly increase moisture content and soil salinity in surficial sediments and, in turn, adversely impact conditions suitable for agricultural crop production. The realignment zone serves as an engineered analog of coastal flooding, presenting an opportunity to investigate how low-lying coastal environments may experience regular flooding in the future due to sea-level rise and intensifying coastal storms.

Soil salinity management practices in coastal area of Bangladesh: a review

Soil salinity is a significant threat to agriculture and livelihood, particularly in the Southern coastal areas of Bangladesh. Soil salinity is extended from 0.833 to 1.056 million hectares (about), with an increase of 26% between 1973 and 2009. Out of about 1.689 million hectares of coastal land, about 1.056 million hectares are affected by soil salinity of various degrees covering 49 Upazila (sub-district) of 19 districts. About 0.328, 0.274, 0.189, 0.161, and 0.101 million hectares of land are affected by very slight (S1), slight (S2), moderate (S3), strong (S4), and very strong salinity (S5), respectively. Data recorded by SRDI manifests new ingression of salinity in Narail (18.71 ha), Jashore (14.99 ha), Barishal (13.96 ha), Gopalgonj (6.27 ha), Jhalakati (4.69 ha), and Madaripur (0.72 ha) districts. Soil salinity also encroached a large area of Bhola (53.84 ha), Patuakhali (40.08 ha), Khulna (27.92 ha), and Bagerhat (23.14 ha), besides minor ingression in other districts. The salinity level is almost double (2.8-18.5 to 4.0-42.8 dS/m) from 1973 to 2009 in Sharankhola Upazila of Bagerhat district, Dumuria Upazila of Khulna district and Shyamnagar Upazila of Satkhira district (SRDI, 2010). Different causes are involved in increasing the water and soil salinity of the coastal area of Bangladesh, like withdrawal of fresh river water from upstream, irregular rainfall, faulty management of sluice gates and polders, regular tidal water flooding in an unprotected area, the capillary rise of soluble salts, decreased surface water availability, lowered ground water table, reduced soil moisture content, the introduction of unplanned shrimp cultivation, lack of drainage facilities. Some of the widespread soil and land management techniques adopted in the saline areas of Bangladesh to cope with the salinity are polder (123), farm-pond (khamar-pokor), sarjan procedure, usage of raised shrimp farm bund for year-round cropping, mulching (keeping land covered in winter and summer months), land leveling, pitcher (kolosh) irrigation to grow watermelon, dibbling method, the addition of organic matter, chemical fertilizers and cultivation of saline tolerant crop varieties, particularly rice. Vol. 10, No. 1, April 2023: 1-7