Land Inundation Research Articles

Regional Flood Forecasting using SWMM for Urban Catchment

Urban flooding is the inundation of land or property in a designed atmosphere, significantly in additional densely inhabited areas, caused by precipitation overwhelming the capability of drain systems, like storm sewers. Due to expeditious increment and improper urban designing the probabilities of creek, localized or flash urban floods have drastically multiplied. This study explores the application of Storm Water Management Model (SWMM) to densely populated area of Vijayawada city, which is fragmented into 58 sub-catchments. The study area is delineated in SWMM by the assistance of blueprint AutoCAD maps showing drainage network and Reference Level details. From this elaborated elevation data of drain networks, the flow direction has been evaluated to create the descriptive view of the area in SWMM. In this study area 2016, 2017 and 2018 extreme rainfall events of 24 hrs interval is considered for runoff analysis. The focus of the current wok is to model runoff conditions by applying Dynamic wave equation for routing floods and Green-Ampt equation for infiltration in SWMM. The model outputs guided in visualizing the runoff from extreme precipitation events and to analyze the accuracy of the storm water network system.

Global characterization factors for terrestrial biodiversity impacts of future land inundation in Life Cycle Assessment

Life Cycle Assessment (LCA) is a tool for analyzing and comparing environmental impacts of products throughout their life cycles, facilitating shifts towards more environmentally friendly products. However, LCA does currently not address terrestrial biodiversity impacts related to the conversion of terrestrial habitat into aquatic habitat. This conversion can occur because of sea level rise, establishment of new land-based aquaculture, as well as reservoir expansion or creation. Here, we focus on land occupation and terrestrial biodiversity impacts, while transformation impacts, and habitat gain for aquatic species were beyond the scope of the study. To be able to estimate the regional and global terrestrial biodiversity impacts of future land occupation from terrestrial to aquatic habitat in LCA, we developed new characterization factors (CFs) for 781 terrestrial ecoregions, 5 land cover/use types, and 4 taxonomic groups. The basis for the development of the proposed CFs is the model concept of the currently recommended method for quantifying land use impacts on biodiversity in LCA by the Life Cycle Initiative hosted by United Nations Environmental Program. The global CFs vary between 7.44 E−20 PDF/m2 and 6.25 E−09 PDF/m2, showing that a highly variable terrestrial biodiversity impact of land inundation between land cover/use types, taxonomic groups and ecoregions exists.

Monitoring Coastline Dynamics of Alakol Lake in Kazakhstan Using Remote Sensing Data

Alakol Lake is one of the largest hydrologically closed lake located in Balkash-Alakol River Basin in southeast Kazakhstan. Having a coastline approximately at 490 km, Alakol Lake has faced multiple threats due to both natural and anthropogenic factors as a result of tectonic movements, geology, wind-wave conditions, growing tourism activities, fishing, and transport, etc. The present study aims to investigate the historical trends in coastline changes along Alakol Lake in Kazakhstan and estimate its change rate by using remote sensing data in particular scale-space images Landsat-5 TM, 7 ETM+, 8 OLI, and Sentinel-2A. Based on Landsat and Sentinel data, the modified normalized difference water index was calculated to demonstrate the coastline changes along Alakol Lake between 1990 and 2018. Moreover, the monitoring and analysis of coastline dynamics is based on the main morphometric characteristics of Alakol Lake including water surface area, coastline length, geomorphology of the coast, etc. Our results reveal that there is a continuous coastline retreat, depending on the coast types. For example, in the case of the denudation coasts, a land inundation was from 120 to 270 m between 1990 and 2018. In the case of the accumulative coast (mainly northeast, north, and northwest coasts) a land inundation was from 200 to 900 m. A vast area of agricultural land around Alakol Lake become flooded and lost. This study demonstrates the importance of monitoring coastline dynamics because it provides essential information for understanding the coastal response to contemporary nature and anthropogenic impacts.

Changes in salinity of a clay soil after a short-term salt water flood event

The effects and subsequent recovery from a short-term salt water flood event were studied on a clay soil. Sea inundation of agricultural land caused marine salt water to pond on the soil surface for up to 144 h. The salinity of the soil, how deeply the salt water penetrated into the soil and how quickly salts washed out of the soil were assessed. Elevated salt content was seen most strongly in the top layer (0–2 cm) of the soil and salt concentrations increased with the length of inundation. Maize crops died if inundated for 24 h or more, while ryegrass pasture died after an inundation period of 36 h or more. Flushing of soil particles with fresh rainwater proved effective at lowering the salt content in the top 2 cm of soil. The salt content was considerably lower after one rainfall event of 35 mm and decreased only slightly more after another 165 mm of rain. The combined effect of sea level rise and land subsidence may enhance saltwater contamination and soil salinisation with potential serious environmental and socio-economic impacts, e.g. compromising agriculture. Using salt tolerant grasses as pasture species in these low-lying areas should be further investigated.

Numerical study of tsunami wave run-up and land inundation on coastal vegetated beaches

Vegetation exerts a significant damping effect on tsunami wave run-up on coastal beaches, thus effectively mitigating the tsunami hazard. A depth-integrated two-dimensional numerical model (HydroSed2D, Liu et al., 2008; Liu et al., 2010) is developed to investigate tsunami wave run-up and land inundation on coastal beaches covered with Pandanus odoratissimus (P. odoratissimus). The present model is based on a finite volume Roe-type scheme, that solves the non-linear shallow water equations with the capacity of treating the wet or dry boundary at the wave front. The momentum equations in this model are modified by adding a drag force term, thus considering the resistance effects of vegetation on tsunami waves. The accuracy of the numerical scheme and the vegetation drag force are validated by three experimental cases of dam-break flow propagation in a dry channel, solitary wave propagation in a vegetated flume, and tsunami run-up over an uneven bed. Subsequently, a numerical model is applied to simulate tsunami run-up and land inundation on actual-scale vegetated beaches and a series of sensitive analyses are conducted by comparing numerical results. The obtained numerical results suggest that P. odoratissimus can effectively attenuate tsunami run-up and land inundation distance on coastal beaches, and a higher attenuation rate for tsunami wave can be achieved by increasing both vegetation width and vegetation density. The tsunami wave height is also an important factor that impacts the tsunami wave run-up and land inundation on vegetated beaches.

Human risk assessment of Panchet Dam in India using TOPSIS and WASPAS Multi-Criteria Decision-Making (MCDM) methods

Every river dam activity has definite beneficial effects but cannot circumvent its negative impact in the long run. The Panchet dam has been commissioned as a multipurpose river valley project under the authority of Damodar Valley Corporation (DVC) across the river Damodar at the border of West Bengal and Jharkhand states of India in 1959 to overcome some problems like flood control, supply of irrigation, domestic and industrial water, hydroelectric power generation etc. But it has now become a threat to the surrounding people, due to rapid sedimentation and reduction in its water holding capacity. Human risk assessment of the dam thus claims importance and such an effort is executed in this work using Delphi Questionnaire and two Multi-Criteria Decision-Making (MCDM) methods viz. Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and Weighted Aggregated Sum Product Assessment (WASPAS). At first 9 human risk alternatives (A1-A9) of the dam are identified using Delphi Questionnaire and rated them in order to prioritize using TOPSIS and WASPAS methods. Risk prioritization results of TOPSIS and WASPAS show somewhat differences. The integrated ‘Mean-Rank’ method is applied to provide final priority ranking of the risk alternatives and the result is: A3 > A9 > A8 > A4, A6 > A1 > A7 > A5 > A2 (when WASPAS parameter λ = 0); A3 > A9 > A4, A8 > A2 > A6 > A1 > A5, A7 (when WASPAS parameter λ = 1); A3 > A9 > A8 > A4, A6 > A1 > A2 > A5 > A7 (when WASPAS parameter λ = 0.5). In all cases, A3 (Population Displacement) alternative ranks first and is identified as the top most risk prone alternative among all. The risk of displacement of people due to further inundation of land is rising gradually. This has motivated us for assessment of other human risks of the dam in the work.

Utilizing Landsat Satellite Data (1990-2018) to Detect Water Inundation for the Management of Human Settlements in Coastal Zones

Objective: This study investigates waterinundation in Semarang and Demak and Kendalregencies in Java, Indonesia, utilizingLandsat 5, 7 and 8 satellite imagery, in combination withthe Seamless Digital Elevation Model and National Bathymetry (DEMNAS) data for 50, 100 and 150 year projections. Methods: Water inundation detection using optical methods (passive sensors) such as Landsat is an effective tool, more so when combined with the Normalized Difference Water Index (NDWI) method in Green Near Infrared (NIR) bands. Combining imagery from these remote sensing sources with DEMNAS land elevation data may strengthen future water inundation predictions and gauge land loss or degradation in regions subject to land inundation and sea level rise. Findings/Application: Semarang is currently subjected to coastal water inundation associated with losses of coastal infrastructure, resulting in the relocation of human settlements to more elevated areas. Sayung is a sub-distric, the most severely affected sub-district has previously expierienced an increase of water inundationfrom 1434.7ha (1990), 3489.1ha (2002) to4923.8ha (2002), an approximate 1.5 % of land loss annually. This average water inundation increase equivalent to 32 cm annually is based on DEMNAS data from 1990 to 2018, which may be due to coastal infrastructure which supports inundationin surrounding coastal areas such as Sayung, Demak regency. Keywords: Coastal Management, Land Inundation, Landsat, Normalized Difference Water Index (NDWI), Water Detection

Land inundation and cropping intensity influences on organic carbon in the agricultural soils of Bangladesh

Land inundation is a common occurrence in Bangladesh, mainly due to the presence of two major river systems – the Brahmaputra and the Ganges. Inundation influences land use and cropping intensity. However, there is little information on the influences of the extent of flooding and cropping intensity has on soil organic carbon (SOC), particularly at the landscape level. To investigate these influences, we collected 268 surface (0–30 cm) soil samples from 4 large sites within the two alluviums deposits (the Brahmaputra river and the Ganges river), on a regular grid (1600 m). The findings show that SOC levels are generally low, reflecting the intensity of agriculture and land management practices. SOC variability was higher across the medium high land (MHL) and medium low land (MLL) sites than in the high land (HL) and low land (LL) sites. The relatively low SOC levels and variability in the HL sites indicate soils here might have reached to equilibrium levels due to higher land use intensity. Topographically higher lands (HL and MHL), due to less of inundation, had higher cropping intensities and lower SOC's than lower lands (MLL and LL), which had lower cropping intensities, as they remain inundated for longer periods of time. The findings clearly demonstrate the intrinsic influence of land inundation in driving cropping intensity, land management practices and SOC levels.

New York City Panel on Climate Change 2019 Report Chapter 5: Mapping Climate Risk

New York City Panel on Climate Change 2019 Report Chapter 5: Mapping Climate Risk

The Tsunami Threat to Sydney Harbour, Australia: Modelling potential and historic events

Tsunami modelling of potential and historic events in Australia’s Sydney Harbour quantifies the potentially damaging impacts of an earthquake generated tsunami. As a drowned river valley estuary exposed to distant source zones, these impacts are predominantly high current speeds (>2 m/s), wave amplification and rapid changes in water level. Significant land inundation only occurs for scenarios modelled with the largest waves (9.0 MW source). The degree of exposure to the open ocean and the geomorphology of locations within the Harbour determine the relative level of these impacts. Narrow, shallow channels, even those sheltered from the open ocean, create a bottleneck effect and experience the highest relative current speeds as well as elevated water levels. The largest maximum water levels (>8 m) occur in exposed, funnel-shaped bays and wave amplification is greatest at locations exposed to the open ocean: >7 times deep water wave heights for 9.0 MW source waves. Upstream attenuation rates of runup and maximum water level show a linear correlation with wave height parameters at the 100 m depth contour and may provide some predictive capabilities for potential tsunami impacts at analogous locations. In the event of a tsunami in Sydney Harbour, impacts may threaten marine traffic and infrastructure.

An assessment of the potential impact of climate change on rice farmers and markets in Bangladesh

Bangladesh, the sixth largest rice producer in the world, has been identified as high risk from the effects of climate change. Many of the adverse impacts of climate change such as land inundation and changes in weather patterns and CO2 levels will impact the agricultural sector. This study develops a partial-equilibrium multi-regional farm household model of Bangladesh rice and non-rice agricultural markets to quantify the impacts of climate change on consumption, production, prices, and farmers’ welfare. The model is calibrated to the Bangladesh rice market using Household Income and Expenditure Survey data. The model is simulated to analyze the impact of land reduction and productivity decline resulting from climate change. The results show that the decline in production in the coastal and northern regions offsets the production increase in the central and eastern regions, and the simulation predicts that total rice production for Bangladesh falls by about 2%. As total rice consumption falls and imports rise, the net effect leads to a rise in the rice price by 5.71% and a decline in farmers’ welfare. Sensitivity analysis shows that more- (less-) effective abatement technology could play a key role in mitigating (exacerbating) the price and welfare effects. The model predicts that many farmers in regions directly impacted by climate change could leave farming in search of off-farm work. Thus, the government can ease this transition by promoting urban development to provide more job options and technical training for farmers.

Simulation-based assessment of the impact of fertiliser and herbicide application on freshwater ecosystems at the Three Gorges Reservoir in China

Dams have profound impacts on river ecosystems, amongst them inundation of land, altered dynamics of the water body or uprising reservoir backwaters influencing tributary or upstream river sections. Along the outstandingly ecologically important Yangtze River in China, the Three Gorges Reservoir (TGR) is the largest project, covering an area of 1080 km2. From the beginning, the dam-project came in for criticism on increasing environmental risks due to sub-merging former industrial and urban areas.We simulated dynamics of biotic and abiotic components of the TGR ecosystem (trophic guilds of aquatic organisms, hydrodynamics, nutrients), as well as the behaviour of the herbicidal substance propanil and its metabolites 3,4-Dichloroaniline (DCA) and 3,3′,4,4′-tetrachloroazoxybenzene (TCAB). A modelling environment, provided by the AQUATOX software, was adapted to the specific situation at a tributary reach to the Yangtze river ‘Daning River’. As the simulated food web contained several interconnected trophic levels, a significant biomagnification of metabolites was demonstrated by our simulation studies. In particular, newly emerging stagnant downstream sections of tributaries exhibited high probabilities due to accumulating pesticides from upstream sources.The common problem of algal blooms in the TGR-region was addressed by dose-response simulation experiments with essential nutrients. Impacts on structure and abundance of populations of aquatic organisms were shown. However, even high nutrient loads resulted in only slight changes of densities of organisms of all trophic levels. Nevertheless, the probabilities for large-scale algal blooms affecting drinking water quality were considered low because of high flow velocities and discharge rates towards the Yangtze River.We see high potential of simulation-based assessments that provide information for risk managers dealing with whole catchment areas. They are put in the position to differentiate the magnitude of impacts of various factors and decide about the most effective remediation measures.

Adequacy of the daily TMPA 3B42 high-resolution satellite precipitation product for monitoring hydrometeorological hazards in the Southeast Sahel of Africa

ABSTRACTRural hamlets in the Southeast Sahel, because of their pastoral setting and dependence on local agricultural production, are particularly vulnerable to flash flooding, loss of soil and the inundation of arable land caused by sudden storm events. High resolution satellite precipitation estimates (SPEs) could prove essential for detecting, monitoring, predicting and mitigating the effects of such hydrometeorological extremes. The focus of this report is on assessing – in the context of the needs of the local community − the effectiveness of what has become the gold standard for such applications in Africa and elsewhere since 1998: Tropical Rainfall Monitoring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) program’s 0.25° × 0.25°, daily 3B42 Version 7 satellite-gauge merged product. The scientific community now has almost 20 years of TMPA data that will likely play a significant role well into the future for retrospective studies in conjunction with the next generation (post-2014) Global Precipitation Mission (GPM) products. To assess the 3B42 product for the purposes of this report, we employ a pixel-to-point comparison of 3B42 daily time series with synchronous gauge data at four well-separated gauge sites. While others have found notable agreement between 3B42 and gauge observations aggregated over large areas and seasonal to annual time periods, it is a different matter downscaling to daily values at local sites, where we find a disturbing number of ‘false alarms’ and ‘missed events’. More than 90% of the total annual rainfall estimated by the 3B42 is contributed by daily events that are misaligned in time or intensity with gauge events. This largely concurs with the findings of our prior reports based on CPC-RFE2 0.1° × 0.1° daily values. Thus, users might be cautious in using the TMPA 3B42, CPC-RFE2 or, by inference, any SPE, as deterministic metrics for detecting and monitoring short term (i.e. ≤ 1 day), extreme storm events in this area of the Sahel.

Mapping of Flood Risk Zones in Ala River Basin Akure, Nigeria

Floods are water induced disasters that lead to temporary inundation of dry land and cause serious damages in the affected location such as loss of lives and properties and destruction of infrastructures. Nigeria has experienced a lot of flood incidences and the impact of flood has also increased due to population growth coupled with uncontrolled developmental practices. The result of this is pressure and congestion in urban land areas. This in turn forces a considerable number of people to settle in unsafe areas with inherent risk to flood which is the case in Ala river basin, Akure, Ondo state. The aim of this research study to make an assessment of flood risk vulnerability in Ala river basin area. Multicriteria Evaluation methods were used to analyse flood vulnerable areas. The causative factors of flood within the basin taken into consideration includes slope, distance to drainage, drainage density, soil type and land use. Geographical information system was integrated with Fuzzy Logic to classify the various causative criteria. Fuzzy overlay was used to generate the flood risk map in Ala river basin identifying low, medium and high flood risk zones which would be made available to policy and decision makers as a decision support system in tackling flood.

Land use changes resulting from construction of Deduru oya reservoir and its’ impacts on livelihood

Construction of a large dam is one of the major economic and development activities that change the existing land use patterns in an area. The major visible impact of dam construction is the inundation of important land uses/ land cover in the reservoir area. This study was conducted to assess the land use/ land cover changes as the result of DeduruOya reservoir construction. Multi temporal satellite images acquired through Google earth were used to identify the land use/ land cover of the reservoir area before and after dam construction. In addition, land use/ land cover changes in a 100 m buffer zone from the reservoir were also evaluated. A total of approximately 1178 ha land was inundated by water which included 40% of paddy, 30% of coconutand 27% of forest lands. The loss of paddy production per year due to this inundation was 5,144kg per displaced family according to the analysis creating Rs. 19.81 million of net income loss annually to the country. The economic loss from coconut land was Rs. 64.60 million per year. The economic loss per family as a result of paddy and coconut production foregone is, therefore Rs.144,240/year. Since their food security and income seemed to have been affected severely due to the reservoir construction, the authorities are required to address the livelihood changes of resettled population and make remedial measures as early as possible.The study suggests a comprehensive assessment of the impacts on people due to physical and livelihood displacement.

Vulnerability of coastal Connecticut to sea level rise: land inundation and impacts to residential property

ABSTRACTVulnerability indices at the global or national scales require considerable data aggregation where local economic and social impacts remain unnoticed. The goal of this study was to analyze the extent of inundated land from sea level rise and its economic impacts to residential property in coastal communities. Geographic data were integrated with economic and social data at parcel level resolution through GIS. Cumulative land inundation in seven coastal municipalities was calculated as 15 and 25 km2, while direct economic costs to residential property was estimated to be $1.3 billion and $2.2 billion for 1 and 2 m sea level rise, respectively. Normalised results were $14 million/km coastline and $4 million/km combined coastline and rivers for 1 m sea level rise. Results indicate that while impacts will mainly occur along the coastline, inland parcels as far as 3 km from the coastline situated along rivers are equally at risk of flooding. While results of the study can be used to estimate economic impacts for other locations that share similar geographic characteristics and development patterns, land use types, proximity to water bodies, and property values are some factors that may lead to differences when these numbers are extrapolated elsewhere.

Climate Change and Urban Flooding: Implications for Nigeria’s Built Environment

Climate change which is the result of global warming relates to seasonal changes occurring in a given geographical area over a long period of time Issues of climate change have in recent times dominated discussions in many local and international fora in view of its perceived devastating consequences affecting rainfall patterns storms and droughts growing seasons humidity and sea levels The inundation of land due to changes in local climate can pose a serious challenge This paper therefore looks at urban flooding as one of the environmental problems associated with extreme weather events arising from climate change and discusses its impact on the built environment It highlights appropriate risk management initiatives that can be implemented to mitigate the general impacts of flooding in Nigeria rsquo s built environment

A GIS based model of rolling easement policies in Pinellas County and Sarasota County, Florida

Florida is the fourth most vulnerable coastal state in the USA to sea level rise (SLR). Studies predict that a 1.20 m rise translates into the displacement of almost five million people and destroys about 2.6 million homes. The only solution to reducing the vulnerability of Florida's coastline is the creation and implementation of coastal policies, including a reduction in armoring and the adoption of policies such as rolling easements. This paper advances a SLR inundation computer model that estimates the costs of applying rolling easement policy through three outcomes: property value loss, property area loss and conservation easement payments to home owners. The GIS computer model is modular which allows new policy components, datasets, or ArcGIS tools to easily be added to the model. The results show that property land inundation and real property losses are primarily linear while rolling easement compensation payments are substantial during the first three scenarios then are largely stable for the remaining SLR steps.

Effects of future sea-level rise on tidal processes on the Patagonian Shelf

The response of tidally driven processes on the Patagonian Shelf to sea-level rise (SLR) is revisited using large but realistic levels of change in a numerical tidal model. The results relate to previous studies through significant differences in the impact, depending on how SLR is implemented. This is true for how the boundary at the coastline is treated, i.e., if we allow for inundation of land or assume flood defences along the coast, but also for how the sea-level change itself is implemented. Simulations with uniform SLR provide a different, and slightly larger, response than do runs where SLR is based on observed trends. In all cases, the effect on the tidal amplitudes is patchy, with alternating increases and decreases in amplitude along the shelf. Furthermore, simulations with a realistic future change in vertical stratification, thus affecting tidal conversion rates, imply that there may be a small but significant decrease in the amplitudes along the coast. Associated processes, e.g., the location of mixing fronts and potential impacts on biogeochemical cycles on the shelf are also discussed.

An Environmental Impact Assessment of the underground operations at the designed Petrikov potash mine, Belarus

Abstract The Petrikov deposits of potash salt is situated in Gomel oblast of Belarus in the south-east of Pripyat Trough, and have Northern and Southern prospects. Underground mining of potash salt will start at the Northern prospect with an area of 166 km2. It is expected that mining will last for between 50-80 years. An Environmental Impact Assessment (EIA) was carried out at the design stage of the Petrikov mining and processing plant. The standard EIA procedure included a set of investigations, including assessments of surface subsidence, changes in groundwater level, changes in productivity of forest phytocoenoses and crops, and assessment of groundwater pollution due to production of potash fertilizers. Maximum values of possible surface subsidence (up to 2.3 m) will occur within the area, where the surface will be affected by the mining of potash layers 1, 2, and 3 of the productive horizon IV-Π, using a long-pillar mining system. Surface subsidence will influence surface topography, surface and groundwater, landscape structure and land resources. The result of surface subsidence will lead to inundation and swamping of land, as well as to an increase in the areas affected by annual floods in the valleys of the Pripyat and Bobrik rivers. Surface subsidence will affect the whole area of the prospect within the limits of planned mining fields, except the areas above safety pillars. In the result of raised groundwater levels the area with groundwater depth of more than 2 m will decrease from 69.1% to 17.8%, and the areas with groundwater depth from 3 to 5 m will disappear. The area with a groundwater depth less than 1 m will increase from 0.1% to 34.0%. In 19.5% of the area the groundwater level will raise above the surface level (the area of inundation). Surface subsidence and change in groundwater level will cause certain decreases in yields of timber and crops, and 2564 ha of forest, 68 ha of arable land and 324 ha of meadows will be inundated. In order to prevent inundation within certain areas protective engineering facilities have been designed, and an arrangement of groundwater monitoring wells has been proposed.