Property:CSDMS meeting abstract
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Delivery of large blocks of rock from steepened hillslopes to incising river channels inhibits river incision and strongly influences the river longitudinal profile. We use a model of bedrock channel reach evolution to explore the implications of hillslope block delivery for erosion rate-slope scaling. We show that incorporating hillslope block delivery results in steeper channels at most erosion rates, but that blocks are ineffective at steepening channels with very high erosion rates because their residence time in the channel is too short. Our results indicate that the complex processes of block delivery, transport, degradation, and erosion inhibition may be parameterized in the simple shear stress/stream power framework with simple erosion-rate-dependent threshold rules. Finally, we investigate the effects of blocks on channel evolution for different scenarios of hydrologic variability, and compare and contrast our results with those of more common stochastic-threshold channel incision models. We show that hillslope-derived blocks have a different signature in erosion rate-slope space than the effects of constant erosion thresholds, and propose characteristic scaling that could be observed in the field to provide evidence for the influence of hillslope-channel coupling on landscape form. +
Delta environments, on which over half a billion people live worldwide, are sustained by sediment delivery. Factors such as subsidence and sea level rise cause deltas to sink relative to sea level if adequate sediment is not delivered to and retained on their surfaces, resulting in flooding, land degradation and loss, which endangers anthropogenic activities and populations. The future of fluvial sediment fluxes, a key mechanism for sediment delivery to deltas, is uncertain due to complex environmental changes which are predicted to occur during the coming decades. Fluvial sediment fluxes under environmental changes were investigated to assess the global sustainability of delta environments under potential future scenarios up to 2100. Climate change, reservoir construction, and population and GDP (as proxies for other anthropogenic influences) change datasets were used to drive the catchment numerical model WBMsed, which was used to investigate the effects of these environmental changes on fluvial sediment delivery. This method produced fluvial sediment fluxes under 12 scenarios of climate and socioeconomic change which are used to assess the future sustainability of 47 deltas, although the approach can be applied to deltas, rivers, and coastal systems worldwide. The results suggest that fluvial sediment delivery to most deltas will decrease throughout the 21st century, primarily due to anthropogenic activities. These deltas will likely become unsustainable environments, if they are not already, unless catchment management plans are drastically altered. +
Delta integrity is a function of adequate fluvial sediment supply since the form at the shoreline is the result interaction between fluvial and basinal processes. Globally, sediment supply to river deltas has been on the decline. Specifically, present sediment supply to the Niger Delta is less than what is required for a sustained growth. Anthropogenic intervention in the lower Niger Basin and within the delta is the main control of the decrease in sediment supply. Changes in shore form is a main consequence of shifting volume of sediment supply in the Niger Delta region. This study attempts a morphodynamic analysis of shoreline changes along the Niger Delta using recent high resolution remote sensing techniques within the Google Earth Engine Platform. Attempt will also be made to characterise the spatial or temporal variability in shoreline dynamics along the Niger Delta with a view to establish the drivers of change. The study will also attempt to model the future evolution of the Niger Delta given present forcing scenarios. The research is within the overall framework of ensuring a sustainable development within the Niger Delta coastal zone in order to preserve its huge economic and ecological potentials for future generation. +
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Delta morphology is traditionally explained by differences in fluvial energy and wave and tidal energy. However, deltas influenced by similar ratios of river to marine energy can display strikingly different morphologies. Other variables, such as grain size of the sediment load delivered to the delta, influence delta morphology, but these models are largely qualitative leaving many questions unanswered. To better understand how grain size modifies deltaic processes and morphologies we conducted 33 numerical modeling experiments using the morphodynamic physics-based model Delft3D and quantified the effects produced by different grain sizes. In these 33 runs we change the median (0.01 – 1 mm), standard deviation (0.1 – 3 φ), and skewness (-0.7 – 0.7) of the incoming grain-size distribution. The model setup includes a river carrying constant discharge entering a standing body of water devoid of tides, waves, and sea-level change. The results show that delta morphology undergoes a transition as median grain size and standard deviation increase while changing skewness has little effect. At low median grain size and standard deviation, deltas have elongate planform morphologies with sinuous shorelines characterized by shallow topset gradients ranging from 1 x 10<sup>-4</sup> to 3 x 10<sup>-4</sup>, and 1 - 8 stable active channels. At high median grain size and standard deviation, deltas transition to semi-circular planform morphologies with smooth shorelines characterized by steeper topset gradients ranging from 1 x 10<sup>-3</sup> to 2 x 10<sup>-3</sup>, and 14 - 16 mobile channels. The change in delta morphology can be morphodynamically linked to changes in grain size. As grain size increases delta morphology transitions from elongate to semi-circular because the average topset gradient increases. For a given set of flow conditions, larger grain sizes require a steeper topset gradient to mobilize and transport. The average topset gradient reaches a dynamic equilibrium through time. This requires that, per unit length of seaward progradation, deltas with steeper gradients have higher vertical sedimentation rates. Higher sedimentation rates, in turn, perch the channel above the surrounding floodplain (so-called ‘super-elevation’) resulting in unstable channels that frequently avulse and create periods of overbank flow. That overbank flow is more erosive because the steeper gradient causes higher shear stresses on the floodplain, which creates more channels. More channels reduce the average water and sediment discharge at a given channel mouth, which creates time scales for mouth bar formation in coarse-grained deltas that are longer than the avulsion time scale. This effectively suppresses the process of bifurcation around river mouth bars in coarse-grained deltas, which in turn creates semi-circular morphologies with smooth shorelines as channels avulse across the topset. On the other hand, finest-grained (i.e. mud) deltas have low topset gradients and fewer channels. The high water and sediment discharge per channel, coupled with the slow settling velocity of mud, advects the sediment far from channel mouths, which in turn creates mouth bar growth and avulsion time scales that are longer than the delta life. This creates an elongate delta as stable channels prograde basinward. Deltas with intermediate grain sizes have nearly equal avulsion and bifurcation time scales, creating roughly semi-circular shapes but with significant shoreline roughness where mouth bars form.
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Delta shoreline structure has long been hypothesized to encode information on the relative influence of fluvial, wave, and tidal processes on delta formation and evolution. However analyses and comparisons of deltaic shorelines have typically been qualitative or utilized relatively coarse quantitative metrics. We ask whether robust quantification of shoreline structure would enable mapping of deltas to a physically-based space in which the relative influence of the different processes could be compared, as has recently been done using a sediment flux budget approach. To explore this question, we analyze Landsat-derived shorelines from more than 50 deltas across the globe. Since the shorelines exhibit variability on scales ranging from tens of meters to tens of kilometers, we propose a multiscale characterization of shoreline structure by mapping the shorelines to a univariate series, through a macro-scale convexity-informed framework, and using localized multi-resolution analysis via wavelets to quantify shoreline variability across a range of spatial scales within and across deltas. Specifically, we focus on the relative energy contributed by meso-scale features (river mouths) and small-scale (less than 1 km scale features). We find that distinct classes of deltas naturally emerge in that metric space, which we attribute to the different processes driving the sources and sinks of sediment in these systems. The analysis suggests the potential towards a quantitative, process-based classification of delta morphology via multi-scale analysis of shoreline structure. +
Deltaic, estuarine, and barrier coasts are experiencing unprecedentedly fast rates of morphological changes, which constitute a threat to people, infrastructures, and economies. Predicting these changes in the future could help to develop cost-efficient mitigation and adaptation plans. Here I present recent progresses in simulating large scale and long term coastal evolution using a new morphodynamic-oriented model. Through opportune simplifications the model simulates tides, surges (hurricanes), wind waves, swells, sand/mud/organic sediment, stratigraphy, and vegetation in a numerically-efficient way. The model reproduces the self-organization of barrier islands and the formation of marshes in the backbarrier/estuarine region. The model emphasizes how mud supply is a major driver for the long-term retreat of marshes. The model also simulates how riverine inputs into backbarrier basins – for example through man-made river diversions – can reduce both marsh edge erosion and barrier island retreat. +
Deltas are home to approximately 7% of global population and play a crucial role in regional food security owing to the favorable conditions for agriculture. As a result, these areas are often heavily irrigated as humans strive to use the local water resource to maximise production. This study aims to incorporate irrigation practices into the LISFLOOD-FP hydrodynamic model to determine the impact of irrigation on the flood dynamics of the Mekong Delta, one of the most intensively irrigated deltas. Irrigation data is based on global databases of irrigation area, crop type and crop calendars, supplemented with local information allowing for this approach to be used across irrigated areas around the world. This study therefore builds upon the localized estimates of flood storage capacity of paddy fields through the region and generates a new estimate across a wider area that is subsequently used to assess the impact on the hydrodynamics and flood inundation pattern. It is envisaged this approach can be used for future analysis of the impact of the changing irrigation practices of the Mekong Delta. +
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Deltas are the important interface between continents and oceans, providing home to over half a billion people. The unique environment supports a wide variety of diverse ecosystems and is highly susceptible to a broad spectrum of interacting forces. Therefore it is critical to understand its current and future changes, especially against the background of climate change and human impact, something that could be explored by studying its historical evolution process. Delta evolution is mainly governed by: a) sediment load supply from its contributing river, and 2) ocean dynamics (e.g. waves, tides). Fluvial sediment supply to a delta fluctuates over time either e.g. due to shifts in climate or, on shorter time scales, due to human interference (e.g. deforestation which could increase sediment supply or the emplacement of dams and reservoirs that reduces the sediment supply). How does this affect the morphology of a delta? Waves interact on deltas by dispersing fluvial sediment, reshaping its shoreline, how will it be illustrated in delta’s shape and morphology?
To study this, we explored hypothetical delta evolution scenarios given the following boundary conditions: a medium size upstream drainage basin (~80,000km2) with, as base case, a typical Mediterranean climate. The analysis is done through coupling two numerical models, HydroTrend and CEM. HydroTrend, a climate-driven hydrological transport model, is applied to replicate freshwater and sediment flux to the delta, and subsequently a coastline evolution model (CEM) is applied to simulate the according changes in the delta’s coastline morphology. A component-modeling tool (CMT) developed by CSDMS, is used to couple the models for this study. Several scenarios are considered that take into account: 1) stepwise increasing fluvial sediment supply, to the delta and 2) the release time of these stepwise sediment increases by changing the storm intensity for periods of time.
Preliminary model experiments will be presented demonstrating: 1) the capability of the CMT to couple models that represent different process domains and were developed and designed independently (i.e. without the intentions of such coupling), 2) the impact of changes in fluvial sediment on deltas.
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Deltas are threatened not only by climate and environmental changes (sea level rise, soil salinization, water shortages and erosion), but also by socioeconomic factors (high population density, intensive land use). These processes threaten people’s livelihoods and wellbeing, and as a result, there is a growing concern that significant environmental change induced migration might occur from deltaic areas. Migration, however, is already happening for economic, education and other reasons (e.g. livelihood change, marriage, planned relocation, etc.). Migration has multiple, interlinked drivers and depending on the perspective, can be considered as a positive or negative phenomenon.
The DECCMA project (Deltas, Vulnerability & Climate Change: Migration & Adaptation) studies migration as part of a suite of adaptation options available to the coastal populations in the Ganges delta in Bangladesh, the Mahanadi delta in India and the Volta delta in Ghana. It aims to develop a holistic framework of analysis that assesses the impact of climate and environmental change, economics and governance on the migration patterns of these areas. The project will test plausible future scenarios and evaluate them by considering a range of perspectives.
The dynamic Bayesian Network integrated model of the DECCMA project formally brings together the project elements in fully coupled, quantitative assessment framework. The presentation introduces the overall integration concept and describes the household decision-making component in detail. This component is based on a detailed household survey from delta migrant sending and receiving areas. We describe the model structure, and contrast the model setup and sensitivities across the three study areas. In doing so we illustrate some key causal relationships between changes in the environment, livelihoods and migration decision. The outputs of the integrative modelling is used to objectively evaluate the simulated environmental, social and economic changes for decision makers including the benefits and disadvantages of migration as an adaptation option.
Deltas exhibit spatially and temporally variable subsidence due, in part, to faulting that lowers the land surface over time, thereby converting subaerial land to open water. In light of expected billion-dollar investments globally to redirect sediment via channel diversions and thus restore delta land, it is crucial to understand whether discrete faulting-induced subsidence events drive distributary channel networks to reorganize. Here, we take inspiration from examples from two deltas of faulting with documented surface expression and with distinct flux-to-shoreline symmetries: the symmetric-flux Selenga River delta (Russia) and the asymmetric-flux Mississippi River delta (Louisiana, USA). Using simulations with the DeltaRCM numerical model resembling these deltaic landscapes, we examine distributary network reorganization to faulting-induced subsidence over a range of surface area and slip displacement. Our findings indicate that in a symmetric-flux delta system, the duration of fault surface expression is strongly and non-linearly related to displacement, because slip above a threshold length-scale drives wholesale channel network reorganization, whereas smaller displacement does not. In contrast, displacement is only weakly related to network reorganization in the asymmetric-flux simulations. In this environment, faults located in areas of the delta not maintaining a surface-water connection to the main channel at the time of the subsidence event do not instigate network reorganization. Moreover, for the range of surface area and slip displacement we examined, areas of faulting also do not significantly influence the distributary network at later times. Nevertheless, all faulting events in simulated deltas, with both symmetric and asymmetric flux, create accommodation space and so inhibit the construction of subaerial land to some degree. +
Densely populated coastal deltas worldwide face cascading flood and salinization hazards associated with sea-level rise, storm surges, dwindling sediment supplies, and land subsidence. One of the greatest hurdles to hazard prediction stems from quantifying the land-subsidence component, which exhibits significant spatial and temporal variations across any given delta. Here, we present a delta-subsidence model capable of quantifying these variations. The model is built upon fundamental principles of effective stress, conservation of mass, and Darcy flow; as well as constitutive relations for porosity and edaphic factors (e.g. roots, burrows). For an input sediment column and deposition rate, we quantify the depth-profile of vertical land motion over time, allowing for direct comparison with field observations spanning various depths, timescales, and methods (e.g., GPS stations; Rod-surface-elevation tables; C14 and OSL ages). Preliminary results demonstrate the model can accurately resolve decadal-scale subsidence patterns on the Ganges-Brahmaputra delta, including subsidence hotspots associated with fine-grained lithologies, buried Pleistocene paleovalleys, and river embankments constructed in the 1950’s. This predictive subsidence model can improve assessments of coastal flood hazards on the Ganges-Brahmaputra and other deltas worldwide; and help inform ongoing billion-dollar restoration efforts facing crucial decisions as to where and when coastal barriers, sediment diversions, and settlement relocations will be implemented in the coming century. +
Deposition of sediment from upland sources has the potential to increase flood risk in downstream riverside communities by reducing the carrying capacity of rivers and causing overbank flow. However, the morphodynamic response of rivers to variable upstream sediment supply remains poorly understood, and operational flood models do not account for sediment in flood prediction.
We introduce a framework for integrating source-to-sink sediment dynamics using coupled hydrological, hydrodynamic and landscape evolution models to quantify and better predict flooding events. A Distributed Hydrology Soil Vegetation Model is used to simulate upland streamflow and land coverage over numerical grids of river networks. Modules from the Python toolkit, Landlab, generate and route sediment from mountain sources (i.e. landslides, exposed glacial till) in the same domain. Streamflow and sediment from these upland models are delivered to a Delft3D hydrodynamic, sediment transport and morphodynamic model to characterize the effects of sediment-routing on lowland, coastal floodplains and investigate the impact on flood risk. This modeling framework is tested for three Puget Sound, WA basins: the Nooksack River, Skagit River and Mt. Rainier drainage, where gage analysis performed on historic USGS indicates regional morphodynamic patterns, with potential implications on flood risk. To ensure accurate model-coupling, the model ensemble is tested in an idealized, Landlab-generated domain.
Funded by the National Science Foundation. +
Depressions are inwardly-draining regions of digital elevation models (DEMs). For modeling purposes, depressions are often removed to create a "hydrologically corrected" DEM. However, this compromises model realism and creates perfectly flat surfaces that must be handled in some other way. If depressions are not removed, the movement of water within them must be modeled. This is challenging because depressions are often deeply nested, one inside the other.
Here, we present a novel data structure – the depression hierarchy – which uses a forest of binary trees to capture and abstract the full topographic and the topologic complexity of depressions. The depression hierarchy can be used to quickly manipulate individual depressions or depression networks, as well as to accelerate dynamic models of hydrological flow, as shown in our Fill-Spill-Merge poster. While the algorithm is implemented in C++ for performance reasons, we have also developed a Python wrapper using the pybind11 library. This enables users to capitalize on the strengths of both languages. The Python wrapper also streamlines the process of integrating the depression hierarchy into the CSDMS model interfaces and Landlab.
Open source code is available on GitHub at https://github.com/r-barnes/Barnes2019-DepressionHierarchy and https://github.com/r-barnes/pydephier. +
Depressions—inwardly-draining regions—are common to many landscapes. When there is sufficient water availability, depressions take the form of lakes and wetlands; otherwise, they may be dry. Depressions can be hard to model, so hydrological flow models often eliminate them through filling or breaching, producing unrealistic results. However, models that retain depressions are often undesirably expensive to run. Our Depression Hierarchy poster shows how we began to address this by developing a data structure to capture the full topographic complexity of depressions in a region. Here, we present a Fill-Spill-Merge algorithm that utilizes depression hierarchies to rapidly process and distribute runoff. Runoff fills depressions, which then overflow and spill into their neighbors. If both a depression and its neighbor fill, they merge. In case studies, the algorithm runs 90–2,600× faster (with a 2,000–63,000× reduction in compute time) than commonly-used iterative methods and produces a more accurate output. Complete, well-commented, open-source code with 97% test coverage is available on Github and Zenodo. +
Depth averaged, adaptive, Cartesian grid models have been used effectively in the modeling of tsunamis, landslides, flooding, debris flows and other phenomena in which the computational domain can be reasonably approximated by a logically Cartesian mesh. One such code, GeoClaw (D. George, R. J. LeVeque, K. Mandli, M. Berger), is already part of the CSDMS model repository. A new code, ForestClaw, a parallel library based on adaptive quadtrees, has been extended with the GeoClaw library. This GeoClaw extension of ForestClaw gives GeoClaw users distributed parallelism and a C-interface for enhanced interoperability with other codes, while maintaining the core functionality of GeoClaw. We will describe the basic features of the ForestClaw code (www.forestclaw.org) and present results using the GeoClaw extension of ForestClaw to model the 1976 Teton Dam failure. If time permits, we will also describe on-going work to model dispersion and transport of volcanic ash using the Ash3d (H. Schweiger, R. Denlinger, L. Mastin, Cascade Volcanic Observatory, USGS) extension of ForestClaw. +
Despite the essential role sub-aerial reef islands on atolls play as home to terrestrial ecosystems and human infrastructure, the morphologic processes and environmental forcings responsible for their formation and maintenance remain poorly understood. Given that predicted sea-level rise by the end of this century is at least half a meter (Horton et al., 2014), it is important to understand how atolls and their reef islands will respond to accelerated sea-level rise for island nations where the highest elevation may be less than 5 meters (Webb and Kench, 2010). Atolls are oceanic reef systems consisting of a shallow reef platform encircling a lagoon containing multiple islets around the reef edge (Carter et al., 1994). Atolls come in a variety of shapes from circular to rectangular and size from 5 to 50 km width of the inner lagoon (Fig. 1a and 1b). I want to understand why atolls vary in their morphology and whether wave climate is the primary driver of atoll morphology. Previous work has highlighted the importance of wave energy on reef morphology and atoll morphology (Stoddart, 1965; Kench et al., 2006). Around a given atoll, the morphology of the reef islands may change significantly from small individual islets or larger continuous islets that are more suitable for human habitation (Fig. 1c and 1d). I will create a global dataset of atoll morphometrics to compare to external forcing, e.g. comparing reef width to the mean wave climate. Using Google Earth Engine, a cloud-based geospatial analysis platform to collate Landsat imagery, I can measure a range of morphometrics including atoll size and shape, reef flat width, reef island size and shape, and distribution of reef islands around an atoll. I will compare these morphometrics to global waves simulated by WaveWatch3. By compiling a global dataset of atoll morphometrics, I am able to better understand the impact of wave climate on atoll morphology and long-term evolution.
References:
Carter, R.W.G., Woodroffe, C.D.D., McLean, R.F., and Woodroffe, C.D.D., 1994, Coral Atolls, in Carter, R.W.G. and Woodroffe, C.D. eds., Coastal evolution: Late Quaternary shoreline morphodynamics, Cambridge University Press, Cambridge, p. 267–302.
Horton, B.P., Rahmstorf, S., Engelhart, S.E., and Kemp, A.C., 2014, Expert assessment of sea-level rise by AD 2100 and AD 2300: Quaternary Science Reviews, v. 84, p. 1–6, doi: 10.1016/j.quascirev.2013.11.002.
Kench, P.S., Brander, R.W., Parnell, K.E., and McLean, R.F., 2006, Wave energy gradients across a Maldivian atoll: Implications for island geomorphology: Geomorphology, v. 81.
Stoddart, D.R., 1965, The shape of atolls: Marine Geology, v. 3.
Webb, A.P., and Kench, P.S., 2010, The dynamic response of reef islands to sea-level rise: Evidence from multi-decadal analysis of island change in the Central Pacific: Global and Planetary Change, v. 72.
Distributed systems of reservoirs (DSR) provide an alternative to large dams and reservoirs for riverine flow regulation and flood management. A DSR consists of temporary, small-in-size reservoirs, or detention ponds, spatially distributed across a watershed. A DSR can be as effective as a single large reservoir in terms of water storage and flow regulation and has overall a limited environmental impact. The effectiveness of a DSR depends, among others, on the number of reservoirs and their locations, making this approach to flood management a geographic problem.
In this work I propose a framework for reservoir modeling and siting. The main research objective is to find the optimal spatial configuration for a DSR that overall maximizes water storage capacity and minimizes reservoir footprint extent and system cost. First, reservoir models are generated on numerous locations along a river network, especially on small streams and tributaries, based on local topography. Shape, geometry and capacity is defined for each candidate reservoir. Then heuristic search is used to find an optimal subset of reservoirs given some spatial and structural cost constraints.
Preliminary results for real watersheds in northeastern Iowa suggest that, costs being equal, DSRs with many reservoirs of small average size have a higher storage capacity than DSRs with fewer reservoirs with a larger average size. That represents the necessary first step for future research on the effect of different configurations of DSRs on flood wave magnitude and propagation, assessing the scale of their benefits and comparing benefits with costs and impacts. +
Drainage capture and divide migration are critical processes that shape tectonically quiescent landscapes. However, the frequency and magnitude of drainage captures, especially under varying lithologic conditions are still poorly understood. In this context, we present the RiverCaptureFinder, a function designed for Landlab that identifies drainage capture events and extracts geomorphic metrics upstream and downstream of the capture point. To explore river captures using this function, we simulate landscape evolution using the StreamPowerEroder function in Landlab. Starting with an equilibrium landscape, we tested several transient scenarios. For scenario 1, we varied the resistant rock layer width (in map view); for scenario 2, we modified the erodibility contrast; and for scenario 3, we explored different uplift rates. In each scenario, RiverCaptureFinder was used to track drainage capture events and compute geomorphic metrics (drainage area, local relief, mean elevation, slope, chi, and ksn). Our preliminary results show that a thinner resistant layer delays drainage capture, results in lower local relief, gentler slopes, and lower ksn values, and ultimately results in smaller captured areas. A thicker resistant layer leads to earlier and larger river captures, higher local relief, steeper slopes, and elevated ksn values for a longer period. Varying erodibility contrast yields similar results, with lower contrast having capture-related geomorphic characteristics similar to the previous scenario with thinner rocks. Conversely, higher contrasts produce geomorphic responses similar to the scenarios with a wider resistant rock. Lastly, even though less significant than the latter, lower uplift delays capture and leads to lower mean elevation, whereas higher uplift increases captured drainage area but reduces mean elevation, local relief, slope, and ksn. In conclusion, the RiverCaptureFinder analysis indicates that drainage captures are more sensitive to changes in rock-resistant thickness (in map-view) and erodibility contrast, which can affect how frequent and how big the captures will be over time in tectonically quiescent landscapes.
Due to its biodiversity, ecosystem services offered and deforestation experienced since the 16th century, there are several protected areas in Atlantic Forest, such as the Juréia-Itatins Mosaic of Protected Areas (MUCJI), state of São Paulo, Brazil. Illegal deforestation in the MUCJI and surroundings have been increasing, caused by urban and agricultural expansion, reducing Atlantic Forest naturalness. This work aimed to simulate scenarios of landscape naturalness of MUCJI and neighboring municipalities for 2050 year, considering the periods 1985-2002 and 2002-2019, which correspond, respectively, to the scenarios before and after the creation of the MUCJI and National System of Protected Areas (SNUC). The landscape naturalness was evaluated by generating Distance to Nature index (D2N) maps for years 1985, 2002 and 2019, which was used as input data in simulation. The forecasting of both scenarios was conducted using cellular automata, weights of evidence and Markov chain, in Dinamica EGO environmental modeling platform. Both forecasted projections suggested that there would be a slight decrease in landscape naturalness. However, the scenario without the MUCJI implementation would reach 165.15 ha of non-natural ecotope in the study area, while the scenario with MUCJI would reach 112.77 ha. The SNUC and the creation of the MUCJI would have been contributed to maintain the naturalness of the study area, reducing losses in landscape naturalness. However, municipal planning and the MUCJI management plans should consider urban and agricultural expansion and access roads as important drivers of loss of landscape naturalness, triggering deforestation and biodiversity damages.
Keywords: Atlantic Forest; Protected Areas; Modeling; Landscape Naturalness; Distance to Nature Index. +
During storms nutrients and contaminants are washed from landscapes into rivers in the form of fine particulate matter. Once in a river, fine particles are typically treated as if they pass through the environment as wash load without interacting with the stream bed. However, laboratory and field experiments have demonstrated that fine particles can be advected towards the bed where they participate in hyporheic exchange and eventual filtration within the river bed. Irreversibly filtered particles can only be remobilized through scour and bed erosion. Therefore, understanding fine particle transport, storage, and remobilization in rivers requires coupling fine particle dynamics and sediment morphodynamics.<br>Here we analyze the dynamics of solute tracers, fine suspended particles, and bed morphodynamics within a coastal stream during baseflow and an experimental flood. These field data represent a unique set of coupled surface and subsurface observations of solute and fine particle dynamics and simultaneous time-lapse photography of sandy bedform motion. From the time-lapse photography, we use novel image analysis techniques to extract time series of bedform wavelength and celerity. In tandem, we utilize existing databases of bedform topography from laboratory experiments to determine relations between the statistical distributions of bedform wavelength, height, and the maximum scour depths. The understanding gained from the high-resolution experimental dataset allows us to create time series of bedform height and scour depth to explore how changing bedform dynamics affects solute and fine particle residence times within the stream bed. +
