Flood Cycle Research Articles

Application of Fluvial-12 model for calculation of maximum deformation in cross sections of tidal rivers (the Karun River in Iran)

In tidal rivers design return period is multiplication of return periods of floods and tidal flows. This research considers the down stream of the Karun River in southwest of Iran as case study. For calibration of Fluvial-12 model, the deformations of river cross sections from 1996 to 2013 were measured by surveying. Using of the Ackers – White (1973) equation eventuates the best fitness between calculated deformations by Fluvial-12 model and observed deformations. This equation is an appropriate sediment transport equation for river beds and banks that their materials are silt or fine sand such as the most of tidal rivers in the world. For design return period N years, the highest erosion occurs at flood return period N years and tidal flow return period 1 year. At cross sections near the mouth of the river the highest sedimentation occurs at flood return period 1 year and tidal flow return period N years but at cross sections far from the mouth of the river the highest sedimentation occurs at flood return period N years and tidal flow return period 1 year. Because sedimentation occurs at flood cycle of tide at near the mouth of the river, tidal flow that its velocity is low causes sedimentation. On the other hand, erosion occurs at ebb cycle of tide and fluvial flow intensifies ebb velocity toward the mouth of the river therefore fluvial flow causes erosion at the whole length of the river.

Long-term persistence of summer annuals in soil seed banks of seasonally dewatered mudflats

In annually flooded and dewatered mudflats, does the big flush of germination following dewatering exhaust the seed bank, and if not, how long can seeds remain viable and nongerminated under annual flooding cycles? Soil samples from mudflats in Land Between the Lakes in western Kentucky and northwestern central Tennessee (USA) were collected in 1990, 1991, and 1992 and annually flooded in winter and kept moist during summer for 15, 14, and 13 years, respectively. Beginning in 1996, all samples were stirred when dewatered in June. Seedlings were counted and removed, thus preventing any input of new seeds. During the study, seeds of 37 species germinated, and there were 2 to 8588 seedlings m−2, depending on the species. Ten of the species germinated in only one set of samples (2–4 seedlings m−2) in 1 year, but the number of years before germination ranged from 1 to 9; one species germinated in two sets of samples (2–4 seedlings m−2) after 6 and 9 years. Eighteen species germinated in 2–12 of the years but not necessarily in consecutive years. Eight species germinated in 14 and/or 15 years. Regardless of seed bank size, seeds of many species lived in the samples for extended periods of time with 31 (83.8%) germinating after ≥ 5 years and 19 (48.6%) after ≥ 10 years. New species appeared in the 1990, 1991, and 1992 samples after 8, 9, and 11 years, respectively. Thus, if the seedling emergence method is used to study mudflat soil seed banks and monitoring is terminated after only a relative short period of time, the size and species richness of the seed bank may be greatly underestimated.

Temporal and spatial dynamics of competitive parapatry in chewing lice.

We synthesize observations from 1979 to 2016 of a contact zone involving two subspecies of pocket gophers (Thomomys bottae connectens and T. b. opulentus) and their respective chewing lice (Geomydoecus aurei and G. centralis) along the Río Grande Valley in New Mexico, U.S.A., to test predictions about the dynamics of the zone. Historically, the natural flood cycle of the Rio Grande prevented contact between the two subspecies of pocket gophers. Flood control measures completed in the 1930s permitted contact, thus establishing the hybrid zone between the pocket gophers and the contact zone between their lice (without hybridization). Since that time, the pocket gopher hybrid zone has stabilized, whereas the northern chewing louse species has replaced the southern louse species at a consistent rate of ~150 m/year. The 0.2–0.8 width of the replacement zone has remained constant, reflecting the constant rate of chewing louse species turnover on a single gopher and within a local pocket gopher population. In contrast, the full width of the replacement zone (northernmost G. centralis to southernmost G. aurei) has increased annually. By employing a variety of metrics of the species replacement zone, we are better able to understand the dynamics of interactions between and among the chewing lice and their pocket gopher hosts. This research provides an opportunity to observe active species replacement and resulting distributional shifts in a parasitic organism in its natural setting.

Is flash flood cycle? A preliminary climate study on Teunom fluvial system

The atmospheric dynamics in the Teunom region have caused flashflood several times in last decade, especially in the Krueng Tenom river basin. This problem has been speculated for many scientists who predicted that such flashflood were caused by either regional climate change or the uncontrolled land use in this area. However, it should also be understood the possibility that flash floods may be caused by regional atmospheric cycle. Therefore, this study aims to understand how the climate approach on temperature and rainfall as meteorology process as a way to comprehend whether the flashflood cycle. The result of the research shows that flashflood is actually cyclical, however, due to micro climate change that happened and it is predicted that land use change or land conversion and illegal mining accelerates flashflood cycle so that early warning system is difficult to be implemented.

CONE: A Connected Dominating Set-Based Flooding Protocol for Wireless Sensor Networks.

Wireless sensor networks (WSNs) play a significant role in a large number of applications, e.g., healthcare and industry. A WSN typically consists of a large number of sensor nodes which rely on limited power sources in many applications. Therefore, improving the energy efficiency of WSNs becomes a crucial topic in the research community. As a fundamental service in WSNs, network flooding offers the advantages that information can be distributed fast and reliably throughout an entire network. However, network flooding suffers from low energy efficiency due to the large number of redundant transmissions in the network. In this work, we exploit connected dominating sets (CDS) to enhance the energy efficiency of network flooding by reducing the number of transmissions. For this purpose, we propose a connected dominating set-based flooding protocol (CONE). CONE inhibits nodes that are not in the CDS from rebroadcasting packets during the flooding process. Furthermore, we evaluate the performance of CONE in both simulations and a real-world testbed, and then we compare CONE to a baseline protocol. Experimental results show that CONE improves the end-to-end reliability and reduces the duty cycle of network flooding in the simulations. Additionally, CONE reduces the average energy consumption in the FlockLab testbed by 15%.

Impact of Unsteady Flow Events on Bedload Transport: A Review of Laboratory Experiments

Recent advances in understanding bedload transport under unsteady flow conditions are presented, with a particular emphasis on laboratory experiments. The contribution of laboratory studies to the explanation of key processes of sediment transport observed in alluvial rivers, ephemeral streams, and river reaches below a dam is demonstrated, primarily focusing on bedload transport in gravel-bed streams. The state of current knowledge on the impact of flow properties (unsteady flow hydrograph shape and duration, flood cycles) and sediment attributes (bed structure, sediment availability, bed composition) on bedload are discussed, along with unsteady flow dynamics of the water-sediment system. Experiments published in recent years are summarized, the main findings are presented, and future directions of research are suggested.

Influential factors on gray brocket deer (Mazama gouazoubira) activity and movement in the Pantanal, Brazil

One of the major challenges in studies of activity and movement ecology is discovering how and why animals behave differently in certain environments. The gray brocket deer (Mazama gouazoubira) is widely distributed in the Neotropic region. In the Brazilian Pantanal wetland, gray brocket deer inhabit a unique landscape with varying ecotypes arranged in a mosaic, where seasonal flooding alters resource availability for the deer. Documenting animal activity and movement can be the key to understanding how a species interacts with its dynamic environment. We used data from accelerometers and characteristics of movement on six GPS-monitored gray brocket deer in the Pantanal wetland to investigate how habitat type, periods of the day, and cycles of flooding and drought affect activity, movement behavior, and displacement. Deer exhibited the lowest activity and encamped movement in closed habitat during diurnal and nocturnal periods, suggesting resting and foraging behaviors. The highest activity and exploratory movement occurred in open habitats, and potentially was related to deer searching for locations with greater resource availability. Individuals were displaced the most during floods, which was a response to access feeding sites that were free of water. Our results not only represent an unprecedented and refined view of the activity and movement behavior of brocket deer, but they also stress the importance of preserving multiple habitat types for species that express variable foraging strategies in heterogeneous landscapes.

Variations in Surface Albedo Arising from Flooding and Desiccation Cycles on the Bonneville Salt Flats, Utah

AbstractDesert playas, such as those in northern Utah, form a landscape often in stark contrast to surrounding mountain ranges due to their minimal topographic relief, lack of vegetation, and saline soils. Dry highly reflective halite surfaces, which make up many of the desert playas in northern Utah, are generally characterized by a surface albedo over 40%. However, their albedo can be reduced abruptly to less than 20% by flooding due to rainfall, runoff from surrounding higher terrain, or surface winds transporting shallow water across the playas. A weather station installed during September 2016 to study the Bonneville Salt Flats (BSF) in northern Utah provides estimates of surface albedo that can be related to cycles of flooding and desiccation of the halite surface. The normalized difference water index (NDWI) derived from the MODIS MOD09A1 land surface reflectance product estimates the fractional coverage of surface water over the BSF. NDWI values computed over 8-day periods from 2000 to 2018 highlight year-to-year and seasonal variations in playa flooding events over the BSF. Periods of playa flooding were observed with both ground-based observations and NDWI with sharp reductions in albedo when the surface is flooded.

From disaster to sustainability: breaking the cycle of floods in Houston

The consequences of growing urbanization can be perceived in multiple levels around the globe: overpopulated living conditions, water and air pollution, loss of open space, costly transportation infrastructure, food shortages, fires and floods. The Houston metropolitan area is an example of fast urban growth, with a population increase of more than sixteen percent in seven years, going from 5.8 million people in 2010 to 6.9 million in 2017. By 2045, the robust growth of the region is projected to lead to the addition of approximately five hundred square miles of developed area, including an estimated six million parking spaces, seven hundred eighty million square feet of non-residential uses, and three and a half billion square feet of residential use. The accelerated development, in addition to physical features, geomorphic processes and human activities in the region are believed to have caused Houston to suffer through over fifty devastating floods since its settlement, despite some successful flood damage reduction projects. The present study focused on the potential outcomes of an increased use of green infrastructure in comparable urban areas, and its effects on flooding volume. Results from the research revealed that not only these measures would likely improve the performance of existing urban drainage systems and attenuate flood incidence in the area, but would also promote connectivity between areas otherwise detached or only accessible by car, improving walkability and incentivizing engagement in outdoor activities.

Plasticity in life history traits of a cyprinid fish in an intermittent river

The extreme seasonal environmental variation of intermittent rivers has a profound effect on freshwater fish communities. Yet, few studies have examined the consequences of the seasonal cycles of flooding and drying to fish condition and reproduction in these ecosystems. In this study, we compared the body condition, reproduction and diet of two chub populations from two adjacent sites (a perennial and an intermittent site) on the main stem of a Mediterranean river (Evrotas River, S. Greece). The study was conducted in spring 2017, three months after flow resumption and before the onset of chub reproductive period. Condition (net weight adjusted for length) of fish did not differ significantly between the two sites, despite lower aquatic macroinvertebrate availability at the intermittent site. Fish at the intermittent site compensated for the lower aquatic prey availability by increasing their feeding intensity and by shifting to higher terrestrial prey consumption. In addition, chub liver weight (adjusted for length) and gonadal weight (adjusted for length) were significantly higher at the intermittent site, indicating higher somatic and reproductive investment. These results highlight the resilience of fish populations inhabiting streams with extreme variation in flow, due to natural and/or anthropogenic drought.

Significance of the connection between bedrock, alluvium and streams: A spatial and temporal hydrogeological and hydrogeochemical assessment from Queensland, Australia

Catchment-scale hydrological and hydrogeological investigations commonly conclude by finding that particular stream reaches are either gaining or losing; they also often assume that the influence of bedrock aquifers on catchment water balances and water quality is insignificant. However, in many cases, such broad findings are likely to oversimplify the spatial and temporal complexity of the connections between the different hydrological system components, particularly in regions dominated by cycles of droughts and flooding. From a modelling perspective, such oversimplifications can have serious implications on the process of identifying the magnitude and direction of the exchange fluxes between the surface and groundwater systems.In this study, we use 3D geological modelling and historic water chemistry and hydraulic records to identify the origins of groundwater at different locations in the alluvium and along the course of streams in the Lockyer Valley (Queensland, Australia), a catchment impacted by a severe drought (‘Millennium Drought’) from 1998 to 2009, followed by extensive flooding in 2011. We also demonstrate how discharge from the sub-alluvial regional-scale volcanic and sedimentary bedrock influences the water balance and water quality of the alluvium and streams. The investigation of aquifer geometry via development of a three-dimensional geological model combined with an assessment of hydraulic data provided important insights on groundwater flow paths and helped to identify areas where bedrock aquifers interact with shallow alluvial aquifers and streams. Multivariate statistical techniques were then applied as an additional line of evidence to groundwater and surface water hydrochemical data from large historical datasets. This confirmed that most sub-catchments within the Lockyer Valley have distinct water chemistry patterns, which result from mixing of different water sources, including discharge from the sub-alluvial bedrock. Importantly, in addition to the observed spatial variability, time-series hydrochemical groundwater and surface water data further demonstrated that the hydraulic connection between alluvial aquifers, streams and sub-alluvial bedrock aquifers is temporally dynamic with very significant changes occurring at the transition from normal to drought conditions and following flooding, affecting both catchment water quality and water balances.

Dam Effect on Soil Nutrients and Potentially Toxic Metals in a Reservoir Riparian Zone

The unique hydrological regime of Three Gorges Dam (TGD) has brought enormous challenges to the riparian zone (RRZ), which plays an important role in regulating sediment and nutrient transport into the Yangtze River. The soil in a RRZ is one of the key factors that affect the water quality. After 4 years of winter‐flooding, the concentration of soil nutrients and potentially toxic metals between the flooded reservoir RRZ and adjacent non‐flooded upland (Upland) are examined. There are two main results: First, soil organic carbon and soil available potassium concentration were significantly lower in RRZ than in Upland. Soil total nitrogen (TN) concentration showed the same trend, but with no significance. Soil available phosphorus concentration is significantly higher in RRZ. Second, the concentrations of all the tested potentially toxic metals (Cd, Cr, Cu, Pb, Zn), their geoaccumulation index (Igeo) values and potential ecological risk index (Ei) values are significantly higher in RRZ than in Upland. Cd had the highest Igeo and Ei values in RRZ. The present results indicated that the flood–dry–flood cycle caused by TGD has changed the soil nutrient concentrations and increased the potentially toxic metal concentrations. There is a cross‐contamination risk of the soil in RRZ, perhaps related to fertilization. As the last protective barrier for the Yangtze River, soil potentially toxic metals pollution control should deserve a considerable attention in the RRZ formed by TGD.

Changes in the Maximum Runoff Regime in the Ussuri River Basin: the Methodological Aspects of Forecasting Based on Dynamic-Stochastic Simulation

The paper discusses the phase of studying the influence of climatic changes on the rainflood runoff of the Ussuri River in the warm season. The algorithm and the methodology of dynamic-stochastic modeling of the river runoff are presented. The annual series of precipitation and runoff observations are analyzed, and the model parameters and the components of the water balance obtained as a result of computer simulation are tested for the presence of significant trends. Sensitivity of the modeling results to changes in the input data and in the parameters of the used Flood Cycle Model (FCM) are estimated. The impact of climatic changes has been found to be manifested as changes in the timelines of the transition seasons (spring and autumn) and in the runoff distribution within a year. The obtained estimates of the impact of different factors on the regime of the rainflood runoff will be used to substantiate the rationale for the scenarios of its long-term prediction.

Possibilities of Flood Forecasting in the West Caucasian Rivers Based on FCM Model

The West Caucasus is the only Russian region where disastrous floods cause a great number of victims regularly. Developing the automated monitoring networks in the Kuban River Basin and Krasnodar Krai has improved the quality of hydrological information over the last years; however, its use for flood forecasting has to be more effective. The paper presents methods of short-term flood forecasting for West Caucasian rivers with rain floods prevalence during the warm season. They are based on applying the Flood Cycle Model (FCM), which has been tested for the first time in the region (the case study of the Tuapse, Psekups, and Pshish rivers). The presented forecasting methods, whose quality completely conforms to the criteria of the Russian Hydrometeorological Service, can enhance the existing hydrological forecasting systems. To further develop the flood forecasting methods for the West Caucasian rivers using physically based models, it is critically important to increase the precipitation measuring network density within the mountain parts of watersheds.

Delta size and plant patchiness as controls on channel network organization in experimental deltas

AbstractUnderstanding the feedbacks between water, sediment, and vegetation in deltas is an important part of understanding deltas as ecomorphodynamic systems. We conducted a set of laboratory experiments using alfalfa (Medicago sativa) as a proxy for delta vegetation to investigate: (1) the effects of plants on delta growth and channel network formation; and (2) the timescales controlling delta evolution in the presence of plants. Experiments were conducted with fluctuating discharge (i.e. flood and base flow periods) and variable seeding densities. We found that when deltas were small, channels had no memory across flood cycles, as floods could completely fill the incised channel network. When deltas were large, the larger channel volume could remain underfilled to keep channel memory. Plant patches also helped to increase the number of channels and make a more distributive network. Patchiness increased over time to continually aid in bifurcation, but as vegetation cover and patch sizes increased, patches began to merge. Larger patches blocked the flow to enhance topset deposition and channel filling, even for the case of large deltas with a high channel volume. We conclude that both plant patchiness and delta size affect the development of the channel network, and we hypothesize that their influences are manifested through two competing timescales. The first timescale, Tv, defines the time when the delta is large enough for channels to have memory (i.e. remain underfilled), and the second, Tp, defines the time when vegetation patches merge, amplifying deposition and blocking channels. When run time is between these two timescales, the delta can develop a persistent distributary network of channels aided by bifurcation around plant patches, but once Tp is reached, the channel network can again be destroyed by vegetation. © 2018 John Wiley & Sons, Ltd.

Plant selection for rain gardens: Response to simulated cyclical flooding of 15 perennial species

Plant selection for rain gardens can be complicated, as cyclic flooding and a gradient of moisture level are expected in the depression structure of a rain garden. However, few studies to date have quantified how plant establishment is affected by rain garden moisture dynamics. This study investigated tolerance of 15 candidate perennial species, which experienced flooding cycles consisting of 1-day and 4-day inundation and draining phases. In this study, detection of species suitability using survival and growth measurements coupled with the stress indicator (i.e. chlorophyll fluorescence) provided a valid framework for wider use in plant selection for rain gardens. The methodology is also confident in predicting the possible placing in different plant moisture zones. All species survived the cyclic flooding treatments and grew to their maximum. Photosynthesis and physical growth in only a few candidate species (e.g. Amsonia tabernaemontana var. salicifolia, Gaura lindheimeri, Sanguisorba tenuifolia ‘Purpurea’ and Thalictrum aquilegifolium) tended to be inhibited by treatments adopting 4-day cyclic flooding, whilst tolerance to 1-day cyclic flooding was clearly demonstrated in most species. Analysis suggests that most species assumed to withstand infrequent to periodic inundation, such as Iris sibirica, Filipendula purpurea and Miscanthus sinensis, are resilient species and are sensible for use in a wider range of rain garden moisture conditions from damp depression bottom to dry margin. Species assumed to be intolerant of inundation such as Gaura lindheimeri may be successful in the rain garden environment, but they are recommended for the dryer zones.

Spatial modeling improves understanding patterns of invasive species defoliation by a biocontrol herbivore

Spatial modeling has proven to be useful in understanding the drivers of plant populations in the field of ecology, but has yet to be applied to understanding variation in biocontrol impact. In this study, we employ multi-scale analysis (Moran’s Eigenvector Maps) to better understand the variation in tree canopy exposed to defoliation by a biocontrol beetle (Diorhabda spp.). The control of the exotic tree Tamarix in riparian areas has long been a priority for land managers and ecologists in the American southwest. Diorhabda spp. was introduced as a bio-control agent beginning in 2001 and has since become an inseparable part of Tamarix-dominated river systems in the southwest. Between 2013 and 2016 tamarisk dieback was assessed at 79 sites across Grand County, Utah, arguably the epicenter of Diorhabda impact in the U.S. Canopy cover of Tamarix was between 73 and 81% at these sites, with the percent that was live cover fluctuating by year with a minimum of 42%. Using a traditional general linear model, we found that readily and commonly measured environmental factors could explain only up to 26% of the variation in Tamarix live canopy each year. The number of defoliations was correlated with an increase rather than a decrease in percent live canopy, suggesting compensatory growth. Spatial structure alone explained 22–40% of variation. We found fine scale spatial structure at less than 10 km and broad scale spatial structure from 10 to 30 km. Combining both traditional and novel spatial statistical methods we increased that percentage to 43–63%, depending on year. These results suggest that scientists and land managers must look beyond commonly measured environmental variables to explain non-random biocontrol impact in this system. In particular, this study points to the potential for biotic interactions and variation in flood cycles for further exploration of the identified spatial structure.

Tracking Groundwater Levels Using the Ambient Seismic Field

AbstractAquifers are vital groundwater reservoirs for residential, agricultural, and industrial activities worldwide. Tracking their state with high temporal and spatial resolution is critical for water resource management at the regional scale yet is rarely achieved from a single type of groundwater data. Here we show that variations in groundwater levels can be mapped using perturbations in seismic velocity (dv/v). We measure dv/v in the San Gabriel Valley, California, from cross correlation of the ambient seismic field. dv/v reproduces the groundwater level changes that are marked by the multiyear depletions and rapid recharges, typical of California's cycles of droughts and floods. dv/v correlates spatially with vertical surface displacements and deformation measured with the Global Positioning System (GPS). Our results successfully predict the volume of water lost in the San Gabriel Valley during the 2012–2016 drought and thus provide a new, complementary approach to monitor groundwater storage.

Effects of Flood Pulse Dynamics on Functional Diversity of Macrophyte Communities in the Pantanal Wetland

Environmental variations and plant traits can act as a filter in plant communities, selecting better-adapted species. In wetlands, macrophytes display physiological, morphological and life history plasticity that allows them to adapt to flood dynamics reflecting habitat filtering. Our aim was to evaluate if the functional diversity of macrophytic community varies between the flood phases, noting whether water factors influence the functional diversity and whether the traits that denote adaptation are associated with these phases. We evaluated 11 morphological traits of macrophytes. The floristic survey within and on the edge of twenty ponds was carried out on a monthly basis and the water parameters were measured for two years. The functional diversity was lower in the ‘drought’ and increased over the flood cycle reaching maximum values in the ‘water recession’ phase. ‘Drought’ acted as a filter by selecting only a few adapted species and the ‘water recession’ acted as a transition area combining favourable conditions for the species of both dry and flood. The trait that contributed most to differentiate the functional groups was the life form. We conclude that the environments under spatial and temporal changes support different communities with different functional characteristics.

Atributos de fertilidade dos solos as margens do Rio Paraguai, Pantanal de Cáceres/MT

A natureza do material de origem e os processos de deposição/sedimentação, decorrente do ciclo natural de inundação e seca, conferem aos solos do Pantanal características diferenciadas. O objetivo deste trabalho foi avaliar os atributos de fertilidade em áreas de vegetação nativa as margens do rio Paraguai, Pantanal de Cáceres – Mato Grosso. Foram coletadas amostras de solos deformadas na profundidade de 0,0 a 0,20 m para análises química e granulométrica, e amostras indeformadas na profundidade de 0,0 a 0,10 m para análise da densidade do solo (Ds), em doze áreas entre o município de Cáceres-MT e a Estação Ecológica de Taiamã, apresentando as seguintes classes de solo: Argissolo, Gleissolo, Neossolo e Planossolo. As análises químicas de fertilidade dos solos foram realizadas em todas as amostras coletadas, constando: pH em H2O, pH SMP, teores de P, K+, Ca2+, Mg2+, acidez trocável (Al3+), acidez potencial (H+Al) e matéria orgânica (M.O), sendo calculado a soma de bases (SB), a capacidade de troca de cátions (CTC pH 7,0 e CTC efetiva), a saturação por bases do solo (V) e a saturação por alumínio (m). Na análise física, foram determinadas a granulometria e a densidade do solo (Ds). Através da análise de regressão foram estabelecidas equações entre a acidez potencial (H+Al) determinada por acetato de cálcio tamponado a pH 7,0 e os valores do pH SMP visando obter uma equação que melhor descreva a relação entre essas duas variáveis, para estimar a acidez potencial. Entre as áreas amostradas, a área com presença de Neossolo apresentou as melhores características em relação a fertilidade natural do solo, entretanto a elevada acidez trocável foi verificada na maioria dos solos, pode causar restrições ao crescimento e desenvolvimento das plantas nas margens do rio Paraguai. A acidez potencial desses solos poderá ser estimada pelo método do pH SMP através da equação H + Al = 24,1861 - 3,3144 x pH SMP.