Expected Water Levels Research Articles

FFM: Flood Forecasting Model Using Federated Learning

Floods are one of the most common natural disasters that occur frequently causing massive damage to property, agriculture, economy and life. Flood prediction offers a huge challenge for researchers struggling to predict floods since long time. In this article, flood forecasting model using federated learning technique has been proposed. Federated Learning is the most advanced technique of machine learning (ML) that guarantees data privacy, ensures data availability, promises data security, and handles network latency trials inherent in prediction of floods by prohibiting data to be transferred over the network for model training. Federated Learning technique urges for onsite training of local data models, and focuses on transmission of these local models on the network instead of sending huge data set towards central server for local model aggregation and training of global data model at the central server. In this article, the proposed model integrates locally trained models of eighteen clients, investigates at which station flooding is about to happen and generates flood alert towards a specific client with five days lead time. A local feed forward neural network (FFNN) model is trained at the client station where the flood has been expected. Flood forecasting module of local FFNN model predicts the expected water level by taking multiple regional parameters as input. The dataset of five different rivers and barrages has been collected from 2015 to 2021 considering four aspects including snow melting, rainfall-runoff, flow routing and hydrodynamics. The proposed flood forecasting model has successfully predicted previous floods happened in the selected zone during 2010 to 2015 with 84 % accuracy.

Insights into Flood Risk Misperceptions of Homeowners in the Dutch River Delta.

Flooding is one of the most significant natural disasters worldwide. Nevertheless, voluntary take‐up of individual damage reduction measures is low. A potential explanation is that flood risk perceptions of individual homeowners are below objective estimates of flood risk, which may imply that they underestimate the flood risk and the damage that can be avoided by damage reduction measures. The aim of this article is to assess possible flood risk misperceptions of floodplain residents in the Netherlands, and to offer insights into factors that are related with under‐ or overestimation of perceived flood risk. We analyzed survey data of 1,848 homeowners in the Dutch river delta and examine how perceptions of flood probability and damage relate to objective risk assessments, such as safety standards of dikes, as well as heuristics, including the availability heuristic and the affect heuristic. Results show that many Dutch floodplain inhabitants significantly overestimate the probability, but underestimate the maximum expected water level of a flood. We further observe that many respondents apply the availability heuristic.

Flooding of Piazza San Marco (Venice): Physical Model Tests to Evaluate the Overtopping Discharge

This paper aims at evaluating the wave overtopping discharge over the pavement of “Piazza S. Marco” (Venice) in order to select the best option to mitigate the risk of flooding of the Piazza and to protect the monuments and historic buildings, e.g., the “Basilica S. Marco”. In fact, the MO.S.E. (MOdulo Sperimentale Elettromeccanico) system is designed to keep the water level below a certain value, for the safety of the lagoon, but it does not guarantee the defence of the Piazza, where flooding is still possible, being its pavement locally much lower than the maximum expected water level. To completely defend the Piazza, specific additional works are planned to prevent the back-flow through the natural drainage system (now the primary pathway) or by filtration or by overtopping. This paper investigates on the overtopping mechanism, under conditions compatible with a fully operational MO.S.E. system, through 2-D experiments. The pavement of the Piazza is gently sloping towards the masonry quay which, in some parts is formed by 5 descending steps, and in some other parts, is just a vertical wall. Close to the “Marciana” Library, a critical part is present, with a slightly lower crest freeboard. In total, three cross-sections were examined in the 36 m long wave flume of the Padova University. The test programme includes 10 irregular wave attacks and three different water levels. The test results differ considerably from the results of the available formulas, since the investigated cross-sections by far exceed their range of applicability. The presence of the steps affects only the reflection coefficient rather than the overtopping discharges. In general, if the waves incident to the Piazza are higher than 40 cm, which is a possible scenario, some other adaptation works must be considered, such as the pavement rise, temporary barriers or the reduction of the waves impacting the quay through, for instance, floating breakwaters.

Two Models Solutions for the Douro Estuary: Flood Risk Assessment and Breakwater Effects

Estuarine floods are one of the most harmful and complex extreme events occurring in coastal environments. To predict the associated effects, characterize areas of risk, and promote population safety, numerical modeling is essential. This work performs a comparison and a combination of two 2-dimensional depth-averaged estuarine models (based on openTELEMAC-MASCARET and Delft3D hydrodynamic software packages), to develop a two-model ensemble approach that will improve forecast robustness when compared to a one-model approach. The ensemble was applied to one of the main Portuguese estuaries, the Douro river estuary, to predict the expected water levels associated with extreme river discharges in the present-day configuration with the new breakwaters. This is a region that is periodically under heavy flooding, which entails economic losses and damage to protected landscape areas and hydraulic structures. Both models accurately simulated water levels and currents for tidal- and flood-dominated validation simulations, with correlation values close to 1, RMSE below 15%, and small Bias and Skill coefficient close to 1. The two-model ensemble results revealed that the present-day estuarine mouth configuration will produce harsher effects for the riverine populations in case identical historical river floods take place. This is mainly due to the increase in the area and volume of the estuary’s sand spit related to the construction of the new breakwaters.

In this issue of Weather

This issue includes a great variety of meteorological topics, including fog forecasting, the measurement of climatic changes as reflected in soil temperatures, the flooding from a thunderstorm, the need to conserve water in a desert region, the communicationnof uncertainty and the relationship of snow and ice with literature in both East and West. Fog forecasting remains difficult for forecasters: numerical models provide some guidance, but both empirical and numerical methods have significant deficiencies. To add to well-established empirical methods, we start with a revised treatment that should aid forecasts of radiation fog, as explained by Anne Barber and Matt Woods in ‘The adapted Middle Wallop technique: a new method of forecasting the fog point’ on p. 255. On p. 260 we move on to an examination of soil temperatures as markers of climate, as described by J Webb, Barbara Amon, Madhu Subedi and Michael Fullen in ‘Temporal changes in soil temperature at Wolverhampton, UK and Hohe Warte, Vienna, Austria 1976–2010’. Rising temperature is evident in their results, but to varying degrees. It will be interesting to see how these measurements continue to change – a marker that is insulated, at least to some extent, from short-period variation. M. Lickiss, K. J. Mulder, A. Black, A. J. Charlton-Perez, R. A. McCloy and R. Chandler look at how forecasters treat the complexity of their science and the associated uncertainty in ‘Developing a quick guide on presenting data and uncertainty’ on p. 266. Getting an appropriate balance, so that the customer knows what is meant, but weather is neither under-, nor over-forecast, remains a difficulty and this paper describees a suitable methodology. Ice and snow have featured in the literature of both East and West, often in an alegorical way. Hisami Nakamura and Julyan Cartwright have already described the early history of ice and snow described in literature in the first two parts of their series. On p. 272, ‘Hot ice and wondrous strange snow – a history of ice and snow – part 3’ they move on, concentrating on Twentieth Century poetry and novels. Just over 20 years ago, heavy thundery rain fell in West Dorset and parts of Devon, as described by Andrew Sibley in ‘Severe thunderstorm and flooding in East Devon on 7 August 1997’ on p. 276. Andrew presents the development of the storm and its effects clearly and the requirements – as well as possible limitations – are evident. On p. 280, we move on to ‘Methodology for the determination of trends for climatic and hydrometric parameters upstream of the Dez Dam’ by A. Adib, A. Navaseri and B. Shenasa. Iran – despite its mountainous interior – is a desert contry and the south of the nation sources much of its water from reservoirs. The expected water levels are strongly dependent on precipitation, so it is increasingly necessary to measure river flow and relate it to other meteorological measurements – especially in a time of changing climate.

RAPID RISK EVALUATION (ER2) USING MS EXCEL SPREADSHEET: A CASE STUDY OF FREDERICTON (NEW BRUNSWICK, CANADA)

Abstract. Conventional knowledge of the flood hazard alone (extent and frequency) is not sufficient for informed decision-making. The public safety community needs tools and guidance to adequately undertake flood hazard risk assessment in order to estimate respective damages and social and economic losses. While many complex computer models have been developed for flood risk assessment, they require highly trained personnel to prepare the necessary input (hazard, inventory of the built environment, and vulnerabilities) and analyze model outputs. As such, tools which utilize open-source software or are built within popular desktop software programs are appealing alternatives. The recently developed Rapid Risk Evaluation (ER2) application runs scenario based loss assessment analyses in a Microsoft Excel spreadsheet. User input is limited to a handful of intuitive drop-down menus utilized to describe the building type, age, occupancy and the expected water level. In anticipation of local depth damage curves and other needed vulnerability parameters, those from the U.S. FEMA’s Hazus-Flood software have been imported and temporarily accessed in conjunction with user input to display exposure and estimated economic losses related to the structure and the content of the building. Building types and occupancies representative of those most exposed to flooding in Fredericton (New Brunswick) were introduced and test flood scenarios were run. The algorithm was successfully validated against results from the Hazus-Flood model for the same building types and flood depths.

RAPID RISK EVALUATION (ER<sup>2</sup>) USING MS EXCEL SPREADSHEET: A CASE STUDY OF FREDERICTON (NEW BRUNSWICK, CANADA)

Conventional knowledge of the flood hazard alone (extent and frequency) is not sufficient for informed decision-making. The public safety community needs tools and guidance to adequately undertake flood hazard risk assessment in order to estimate respective damages and social and economic losses. While many complex computer models have been developed for flood risk assessment, they require highly trained personnel to prepare the necessary input (hazard, inventory of the built environment, and vulnerabilities) and analyze model outputs. As such, tools which utilize open-source software or are built within popular desktop software programs are appealing alternatives. The recently developed Rapid Risk Evaluation (ER<sup>2</sup>) application runs scenario based loss assessment analyses in a Microsoft Excel spreadsheet. User input is limited to a handful of intuitive drop-down menus utilized to describe the building type, age, occupancy and the expected water level. In anticipation of local depth damage curves and other needed vulnerability parameters, those from the U.S. FEMA’s Hazus-Flood software have been imported and temporarily accessed in conjunction with user input to display exposure and estimated economic losses related to the structure and the content of the building. Building types and occupancies representative of those most exposed to flooding in Fredericton (New Brunswick) were introduced and test flood scenarios were run. The algorithm was successfully validated against results from the Hazus-Flood model for the same building types and flood depths.

A simple model for the spatially-variable coastal response to hurricanes

The vulnerability of a beach to extreme coastal change during a hurricane can be estimated by comparing the relative elevations of storm-induced water levels to those of the dune or berm. A simple model that defines the coastal response based on these elevations was used to hindcast the potential impact regime along a 50-km stretch of the North Carolina coast to the landfalls of Hurricane Bonnie on August 27, 1998, and Hurricane Floyd on September 16, 1999. Maximum total water levels at the shoreline were calculated as the sum of modeled storm surge, astronomical tide, and wave runup, estimated from offshore wave conditions and the local beach slope using an empirical parameterization. Storm surge and wave runup each accounted for ∼ 48% of the signal (the remaining 4% is attributed to astronomical tides), indicating that wave-driven process are a significant contributor to hurricane-induced water levels. Expected water levels and lidar-derived measures of pre-storm dune and berm elevation were used to predict the spatially-varying storm-impact regime: swash, collision, or overwash. Predictions were compared to the observed response quantified using a lidar topography survey collected following hurricane landfall. The storm-averaged mean accuracy of the model in predicting the observed impact regime was 55.4%, a significant improvement over the 33.3% accuracy associated with random chance. Model sensitivity varied between regimes and was highest within the overwash regime where the accuracies were 84.2% and 89.7% for Hurricanes Bonnie and Floyd, respectively. The model not only allows for prediction of the general coastal response to storms, but also provides a framework for examining the longshore-variable magnitudes of observed coastal change. For Hurricane Bonnie, shoreline and beach volume changes within locations that experienced overwash or dune erosion were two times greater than locations where wave runup was confined to the foreshore (swash regime). During Hurricane Floyd, this pattern became more pronounced as magnitudes of change were four times greater within the overwash regime than in the swash regime. Comparisons of pre-storm topography to a calm weather survey collected one year after Hurricane Floyd's landfall show long-term beach volume loss at overwash locations. Here, the volume of sand eroded from the beach was balanced by the volume of overwash deposits, indicating that the majority of the sand removed from the beach was transported landward across the island rather than being transported offshore. In overwash locations, sand was removed from the nearshore system and unavailable for later beach recovery, resulting in a more permanent response than observed within the other regimes. These results support the predictive capabilities of the storm scaling model and illustrate that the impact regimes provide a framework for explaining the longshore-variable coastal response to hurricanes.

The New Port of New York and New Jersey Operational Forecast System

he real-time Port of New York and New Jersey Operational Forecast System (NYOFS) became operational on 10 February 2003 at NOAA’s National Ocean Service (NOS) in Silver Spring, Maryland. NYOFS generates hourly nowcasts and hourly forecast guidance out to 30 hours of currents and water levels for the Port region, including Raritan Bay, Newark Bay, and Upper Bay, the Kill Van Kull, Arthur Kill, the lower Hudson River, and the East River. NYOFS graphical products—including time series, maps, and animations of water levels and currents, nowcasts, and forecast guidance—are disseminated through an NOS Web site (http://co-ops.nos.noaa.gov/ NYOFS/nyofs.shtml). The model predictions are displayed as a graph of the water-level height and current velocity at measurement stations and other locations throughout the bay (Fig. 1). The system has been incorporated into NOS’s Physical Oceanographic Real-Time System (PORTS®), which provides an operational monitoring system (24 hours a day, 7 days a week) for quality assurance and control of the NYOFS inputs, operational procedures, and product dissemination. Historically, mariners navigating in New York Harbor have used NOAA’s tide and tidal current tables for the best estimate of expected water levels and currents. However, these tables cannot predict changes due to wind, atmospheric pressure, and river flow, which are often significant (Fig. 2). Furthermore, the tide water level and tidal current predictions are available at only a few locations. Although new technology, such as PORTS, at selected locations maintained by NOS provides near-real-time information to the users, there is still need for more information for assuring navigation safety. These include 1) near-real-time water level and current information at locations without gauges, 2) shortterm (1–2 days) water level and current forecast guidFig. 1. NYOFS nowcast/forecast guidance locations.

Surface flow model: inverse problems and predictions

The inverse problem to estimate the scaling coefficients for infiltration, rainfall, intensity, and roughness in a surface flow model is considered. A probability density function (pdf) is constructed from an observed hydrograph associated with a given rainfall event, the deterministic surface flow model, prior information on bounds on the scale coefficients, and prior information on the coefficients. From this pdf a basin pdf is obtained describing the likelihood of basin infiltration and roughness properties within a sample space of basin properties. With the occurrence of a new rainfall event, the basin pdf is utilized to describe the behavior of the basin in the presence of this event with a basin-event pdf. From this information predictions of flooding behavior may be obtained as well as the expected water levels along the stream. Numerical examples are presented that include different observational errors.

Extreme discharges of the Meuse in the Netherlands: 1993, 1995 and 2100 — Operational forecasting and long term expectations

The River Meuse is an important part of the water management system in the Netherlands. The river and river bed are used for many functions. Because of high discharges large areas were flooded in 1993 and 1995. During floods information about actual and expected water levels is very important as a basis for flood management. Water levels in the Meuse are predicted with the model FLOFOM, consisting of a statistical module, rainfall-runoff models and a hydrodynamic model. For the floods of 1993 and 1995 the forecasts were of good quality. The accuracy for the 12-hours forecast was in most cases within 10 cm. However, improvements like extending the lead-time, are possible and necessary. In relation to floods and river management, it is also important to look at the future. Climate might change with possibly more precipitation in the winter period. Some initial simulations with increased precipitation were carried out with the forecasting model FLOFOM for the floods of 1993 and 1995. Results show a strong increase in peak flow.

Use of synthetic inflow and evaporation sequences in the analysis of the expected water levels of closed basins

Use of synthetic inflow and evaporation sequences in the analysis of the expected water levels of closed basins