A Review of Wetland Remote Sensing <s> Flooding/Inundation <s> Abstract A Landsat image of part of the flooded area of Cooper Creek, Queensland, Australia, in February 1974, shows large dark areas within the flooded valley. The dark areas are believed to be wet, but unflooded, areas of dark alluvial soil. These striking features, which have not previously been identified on Landsat images, must be properly interpreted so as not to confuse them with clear water. <s> BIB001 </s> A Review of Wetland Remote Sensing <s> Flooding/Inundation <s> This paper deals with the experimental activity carried out in the field of flood monitoring at the Civil Engineering Department of Florence University (Italy) in cooperation with EOSAT (USA) and Eurimage (Italy). The aim of the study is to research the possibilities of satellite data utilization to aid in modelling of the hydrological behaviour of a river basin and monitoring flood emergencies. The area selected for the study is the Fucecchio Marsh (Tuscany, Italy), in which flooding events are very frequent. This paper describes the results of the study, with particular reference to the use of Landsat TM data to estimate soil water content, and the use of ERS SAR data to analyse flash flood events. <s> BIB002 </s> A Review of Wetland Remote Sensing <s> Flooding/Inundation <s> The lower River Murray in South Australia is highly regulated through weirs and water extraction for irrigation. Management of the river for environmental purposes requires an understanding of the extent of floodplain inundation from various flows and weir manipulations. This study aimed to produce a floodplain inundation model for the 600 km long and 1–5 km wide portion of the River Murray in South Australia from the New South Wales border to Lake Alexandrina. The model was developed using a Geographical Information System (GIS), remote sensing and hydrological modelling. Flood inundation extents were monitored from Landsat satellite imagery for a range of flows, interpolated to model flood growth patterns and linked to a hydrological model of the river. The resulting model can be analysed for flows ranging from minimum flow to a 1-in-13-year flood event for any month and weir configuration and has been independently tested using aerial photography to an accuracy of approximately 15% underestimate. The results have proven the approach for determining flood inundation over a large area at approximately one-tenth of the cost of detailed elevation and hydrodynamic modelling. The GIS model allows prediction of impacts on infrastructure, wetlands and floodplain vegetation, allowing quantitative analysis of flood extent to be used as an input into the management decision process. Copyright © 2005 John Wiley & Sons, Ltd. <s> BIB003 </s> A Review of Wetland Remote Sensing <s> Flooding/Inundation <s> Many marsh areas in Southern Spain were dewatered during the 1950's for agricultural purposes. These actions were not ::: successful due to the high salinity trend exhibited in such soils, especially notable during the long dry summers in these ::: locations. Recently, many attempts to restore the marshes have been made to try to return the original flooding cycles to ::: the dewatered areas, and promote the development of spontaneous vegetation suitable to salty environments. This work ::: deals with the monitoring of the increase of the flooding area in the San Pedro River marshes (Cadiz) in Spain after the ::: demolition of a dam near the mouth, from the analysis of Landsat TM images with a linear mixture spectral model. ::: Three different components (vegetation, dry soil and wet soil) were quantified in the area over the two years following ::: the destruction of the dam and the increase in tidal entry to the marsh and compared to the results from a previous date. ::: The results were calibrated with field data measured directly on the terrain surface. The model used was capable of ::: discriminating such components with satisfactory accuracy, providing data on the evolution of the flooding area ::: throughout the year and the increase in vegetation distribution one year after the dam break. Differences in the tidal ::: advance along tidal creeks in the main reach of the river before and after the demolition were successfully identified. The ::: impact of the dam action on the development of vegetation was also quantified; the results showed the potential to ::: restore this degraded marsh land. <s> BIB004 </s> A Review of Wetland Remote Sensing <s> Flooding/Inundation <s> ABSTRACT Carle, M.V.; Sasser, C.E., and Roberts, H.H., 2015. Accretion and vegetation community change in the Wax Lake Delta following the historic 2011 Mississippi River flood. During the 2011 Mississippi River flood, discharge to the lower river exceeded that of the 1927 and 1937 floods and the lower river remained above flood stage for nearly 2 months. A combination of WorldView-2 and Land Satellite 5 Thematic Mapper (Landsat 5 TM) imagery was used to assess the impact of this flood event on the Wax Lake Delta, one of few areas where the river is building new land. Vegetation community change was mapped from 2010 to 2011 and related to elevation change using plant species elevation distributions calculated from light detection and ranging (LIDAR) data. Changes in the land area in the delta were also assessed by regressing land area against water level for a series of pre- and postflood Landsat 5 TM images. The results indicate a net growth of 6.5 km2 at mean water level and 4.90 km2 at mean sea level. ... <s> BIB005 </s> A Review of Wetland Remote Sensing <s> Flooding/Inundation <s> Summary Flood dependent aquatic ecosystems worldwide are in rapid decline with competing demands for water. In Australia, this is particularly evident in the floodplain wetlands of semi-arid regions (e.g. the Macquarie Marshes), which rely on highly variable flooding from river flows. Environmental flows mitigate the impacts of river regulation, inundating floodplains, thereby rehabilitating degraded habitats. Mapping flooding patterns is critical for environmental flow management but challenging in large heterogeneous floodplains with variable patterns of flooding and complex vegetation mosaics. We mapped inundation in the Macquarie Marshes, using Landsat 5 TM and Landsat 7 ETM+ images (1989–2010). We classified three inundation classes: water, mixed pixels (water, vegetation, soil) and vegetation (emergent macrophytes obscuring inundation), merged to map inundated areas from not-inundated areas (dry land). We used the Normalised Difference Water Index (NDWI B2/B5 ), masked by the sum of bands 4, 5, and 7 (sum457), to detect water and mixed pixels. Vegetation was classified using an unsupervised classification of a composite image comprising two dates representing vegetation senescence and green growth, transformed into two contrasting vegetation indices, NDVI and NDI B7/B4 . We assessed accuracy using geo-referenced oblique aerial photography, coincident with Landsat imagery for a small and large flood, producing respective overall accuracies of inundated area of 93% and 95%. Producer’s and user’s accuracies were also high (94–99%). Confusion among inundation classes existed but classes were spectrally distinct from one another and from dry land. Inundation class areas varied with flood size, demonstrating the variability. Inundation extent was highly variable (683–206,611 ha). Floods up to 50,000 ha were confined to the north and south wetland regions. Connectivity to the east region only occurred when flooding was greater than 51,000 ha. Understanding the spatiotemporal dynamics of inundation is critical for quantifying the environmental flow requirements across the suite of biota in the Ramsar-listed Macquarie Marshes. <s> BIB006 </s> A Review of Wetland Remote Sensing <s> Flooding/Inundation <s> Floods are the most expensive natural hazard experienced in many places in the world. The current study aimed at estimating the flooding extent at high return periods in the Cuvelai Basin, southern Angola, where no flow, rainfall or accurate topographic data are available. The flooding study thus relies on remote sensing information: archival optical satellite images, data retrieved from the global flood detection system (GFDS) and Tropical Rainfall Measurement Mission data to help characterize flooding events and determine their extents for high return periods, well beyond the available remote sensing record. Landsat and Earth Observing-1 Mission satellite images are used as optical images. The GFDS provides a monitoring of ongoing flood events everyday. Comparison revealed that the GFDS values in the wetland areas are always less than the other satellite flooding extent by about 25 km2. Frequency analysis was undertaken on the annual maxima flooded areas for monitored GFDS locations using Gumbel distribution. The frequency analysis shows that the potential inundation areas for the 100-year flood event increase by 25 % (±5 %) more than the 10-year event. The remote sensing for the 2009 Landsat image is used to get approximately the flooded areas for the 10-year return period for the whole basin. To assess flooding areas for higher return periods such as the 100-year event, the flooded areas are increased based on the frequency analysis ratio results to give the 100-year inundation extents. Interpolation is undertaken for areas where no data are available from the GFDS website. The Cuvelai Basin inundation areas are thus estimated for non-recorded flooding events. <s> BIB007 </s> A Review of Wetland Remote Sensing <s> Flooding/Inundation <s> The location and persistence of surface water (inland and coastal) is both affected by climate and human activity and affects climate, biological diversity and human wellbeing. Global data sets documenting surface water location and seasonality have been produced from inventories and national descriptions, statistical extrapolation of regional data and satellite imagery, but measuring long-term changes at high resolution remains a challenge. Here, using three million Landsat satellite images, we quantify changes in global surface water over the past 32 years at 30-metre resolution. We record the months and years when water was present, where occurrence changed and what form changes took in terms of seasonality and persistence. Between 1984 and 2015 permanent surface water has disappeared from an area of almost 90,000 square kilometres, roughly equivalent to that of Lake Superior, though new permanent bodies of surface water covering 184,000 square kilometres have formed elsewhere. All continental regions show a net increase in permanent water, except Oceania, which has a fractional (one per cent) net loss. Much of the increase is from reservoir filling, although climate change is also implicated. Loss is more geographically concentrated than gain. Over 70 per cent of global net permanent water loss occurred in the Middle East and Central Asia, linked to drought and human actions including river diversion or damming and unregulated withdrawal. Losses in Australia and the USA linked to long-term droughts are also evident. This globally consistent, validated data set shows that impacts of climate change and climate oscillations on surface water occurrence can be measured and that evidence can be gathered to show how surface water is altered by human activities. We anticipate that this freely available data will improve the modelling of surface forcing, provide evidence of state and change in wetland ecotones (the transition areas between biomes), and inform water-management decision-making. <s> BIB008 </s> A Review of Wetland Remote Sensing <s> Flooding/Inundation <s> The science and management of terrestrial ecosystems require accurate, high-resolution mapping of surface water. We produced a global, 30-m-resolution inland surface water dataset with an automated algorithm using Landsat-based surface reflectance estimates, multispectral water and vegetation indices, terrain metrics, and prior coarse-resolution water masks. The dataset identified 3,650,723 km2 of inland water globally – nearly three quarters of which was located in North America (40.65%) and Asia (32.77%), followed by Europe (9.64%), Africa (8.47%), South America (6.91%), and Oceania (1.57%). Boreal forests contained the largest portion of terrestrial surface water (25.03% of the global total), followed by the nominal ‘inland water’ biome (16.36%), tundra (15.67%), and temperate broadleaf and mixed forests (13.91%). Agreement with respect to the Moderate-resolution Imaging Spectroradiometer water mask and Landsat-based national land-cover datasets was very high, with commission errors <4% and omission errors <14% relative to each. Most of these were accounted for in the seasonality of water cover, snow and ice, and clouds – effects which were compounded by differences in image acquisition date relative to reference datasets. The Global Land Cover Facility (GLCF) inland surface water dataset is available for open access at the GLCF website (http://www.landcover.org). <s> BIB009 </s> A Review of Wetland Remote Sensing <s> Flooding/Inundation <s> Abstract Following extreme flooding in eastern Australia in 2011, the Australian Government established a programme to improve access to flood information across Australia. As part of this, a project was undertaken to map the extent of surface water across Australia using the multi-decadal archive of Landsat satellite imagery. A water detection algorithm was used based on a decision tree classifier, and a comparison methodology using a logistic regression. This approach provided an understanding of the confidence in the water observations. The results were used to map the presence of surface water across the entire continent from every observation of 27 years of satellite imagery. The Water Observation from Space (WOfS) product provides insight into the behaviour of surface water across Australia through time, demonstrating where water is persistent, such as in reservoirs, and where it is ephemeral, such as on floodplains during a flood. In addition the WOfS product is useful for studies of wetland extent, aquatic species behaviour, hydrological models, land surface process modelling and groundwater recharge. This paper describes the WOfS methodology and shows how similar time-series analyses of nationally significant environmental variables might be conducted at the continental scale. <s> BIB010
Floodplains are transitional zones of aquatic and terrestrial environments  . Wetlands are the water storages of flood plains  . The location and extent of inundation need to be understood to manage rivers or flood plains. Landsat data have been used for flood mapping or to build flood models in wetland flood studies  BIB006  BIB007 BIB004 BIB001 . Robinove BIB001 pioneered the use of Landsat images when mapping floods in Queensland, Australia. He proposed that the dark areas in the Landsat images are wet soil but not flooded regions. NDWI and sum of bands 4, 5, and 7 derived from Landsat TM and ETM+ images were used by Thomas et al. BIB006 to map the inundation in Macquarie Marshes in New South Wales. They checked the accuracy of the inundation map results using aerial photography and found that the overall accuracies reached 93%-95%. Based on Landsat TM and other land cover data, Todhunter and Rundquist  reported a 53% increase of the terminal lake area and 426% increase of the area of rural wetland ponds in Devils Lake Basin in North Dakota of the United States; the increased areas cause floods. Frazier and Page  used Landsat TM images before and after the flood to describe the relationship between flow regulation and inundation in floodplain wetlands. The results show that river regulation could reduce the duration and frequency of inundation. Polo and Gonzálezdugo BIB004 monitored the flooded area change and vegetation development after the dismantling of the dam near the mouth of San Pedro River Marsh in Spain using the Spectral Mixture Model (SMM). They concluded that Landsat data were suitable to characterize the two aspects mentioned above both with respect to spatial and temporal resolution. Using millions of Landsat images, Pekel et al. BIB008 quantified the global changes of surface water between 1984 and 2015 and found almost 90,000 km 2 permanent surface water disappeared and new 184,000 km 2 formed. They also analyzed the reasons of these changes in different regions and found that long-term droughts and human activities are the most important influence factors. Feng et al. BIB009 produced a global dataset of surface water at 30 m resolution based on 8756 Landsat data and found the inland water area is 3,650,723 km 2 . Overton BIB003 built an inundation model based on GIS, RS, and a hydrological model. Landsat TM images were used to monitor the extent of flood inundation. It was reported that the model identifies flood inundation at a large area and lower cost. Profeti and Macintosh BIB002 used Landsat TM and European Remote Sensing (ERS) Synthetic Aperture Radar (SAR) to model the hydrological behavior and flood; Landsat TM was used to estimate soil water content. Wang  proposed an efficient and economical approach to map the flooded area in a coastal floodplain. They used the reflectance features of water and land from Landsat images before and after the flood to monitor the extent of the flood and obtained satisfactory results. Carle et al. BIB005 used Landsat TM and other images to assess the impact of the 2011 Mississippi River flood on Wax Lake Delta. Their results indicated that the infrequent and large floods are important for the maintenance of river deltas. Using a time series of Landsat images, Mueller et al. BIB010 described a method to observe water in Australia. Decision trees and logistic regression were used in their research to distinguish persistent and ephemeral water.