Elevated Water Levels Research Articles

Hydraulic response of fibre-reinforced sand subject to seepage

A series of upward seepage tests on unreinforced and reinforced sand specimens was conducted to investigate the influence of soil density and fibre parameters (i.e. fibre contents and lengths) on the piping failure mode, hydraulic conductivity k, and critical hydraulic gradient icr of fibre-reinforced soil (FRS). Direct shear tests were also performed to establish the relationships between soil shear strength and icr of FRS. A dataset of seepage tests on FRS was compiled from a literature review to assess the overall variation of k and icr with fibre content. The test results revealed that k decreases and icr increases as the fibre content increases. The fibre is more effective in dense specimens than in loose specimens. The test results also indicate the icr of FRS is strongly correlated to its soil shear strength. Finally, two case examples, unreinforced and reinforced embankments subject to flood-induced elevated water level, were analysed numerically. The numerical results demonstrated that the embankment backfilled with FRS possessed the combined merits of soil improvement in both mechanical and hydraulic performance. The use of FRS as backfill can effectively delay the advance of seepage, reduce soil piping potential, and improve system slope stability against seepage.

Sediment Transport Analysis of Sesayap River, Malinau District, North Kalimantan

River could have a very important role in improving the economy of a country when it is correctly and properly utilized. Nevertheless, rivers in Indonesia also have various problems, i.e. erosion and sedimentation which occur in many Indonesian rivers, one of it being the Sesayap River. Because of these problems, it is very important to do analysis on bed load transport, in order to find its amount in the existing river, so that optimal handling on the occurring erosion and sedimentation problems could be performed. This research aimed to obtain the amount of bed load transport in Sesayap River, and then compare it to the field condition. The approaches used in this bed load transport analysis were Einstein approach and Frijlink approach, with data required for the analysis, which was water level elevation, topography data, and sediment gradation data. Based on the result of conducted bed load transport analysis, the bed load transport analysis result in Seluwing area was higher than in the Port area. Therefore, sediment deposition or sedimentation would occur in the river segment on between both locations. Qualitatively or tendentiously, the above results showed consistency with what actually happened, or observed, in the field. If it assumed that the equivalent diameter of bed load is 8 mm, the total of bed load transport on Seluwing area and Port area with Einstein approach are 1,582,263 m3 and 1,219,181 m3. Therefore, the sedimentary deposit per day could be calculated by calculating difference of bed load transport volume divided with total of the calculation day; which resulted sedimentary deposit per day of 2,859 m3. Whereas by using the Frijlink approach, the total of bed load transport on Seluwing area and Port area were of 1,391,940 m3 and 1,080,200 m3, and sedimentary deposit per day of 2,455m3. Based on the results, in order to normalize the Sesayap River, the dredging needed is 2,859m3/day based on Einstein approach and 2,455m3/day based on Frijlink approach.

Water Level Measurement Altitude Trainer Integrated With Human Machine Interface

This research aims to design a trainer simulator wake height of the water level measurement using microcontroller arduino mega integrated with Human Machine Interface (HMI). This tool is designed to describe a working system of water level elevation measurements as a learning medium HMI. By using a microcontroller arduino mega, all processes in both input and output can be integrated to the HMI using a 7-inch LCD screen.

Key Parameters of Water Level Fluctuations Determining the Distribution of Carex in Shallow Lakes

Identifying critical hydrologic parameters that structuring biological communities is crucial for the conservation and restoration of wetland ecosystems. The present study determined the key parameters of water level fluctuations (WLFs) influencing the distribution of a typical wetland plant, Carex, in shallow lakes along the middle and lower reaches of the Yangtze River. The plant community and environmental variables in 13 shallow lakes with different WLFs were investigated during 2011–2015. A total of 14 parameters included in three components of WLFs were identified, and their effects on the distribution of Carex were analyzed. The results showed that distribution of Carex in the studied lakes differed obviously in time and space. WLFs were the critical factors influencing the taxa distribution, whereas soil organic matter, human disturbance, substrate type, and soil moisture were of little importance. Rate of water level change and elevation above water were the main parameters determining the coverage and biomass of Carex during the spring growing season. In the autumn growing season, rate of water level change, elevation above water, and emergence timing were important. These results provide important insights into the conservation and restoration of Carex and other hygrophytes in shallow lakes in this region.

Elevated Water Level from Wind along the Gulf of Thailand

Prediction of the water level during extreme events is crucial for coastal management. When the wind blows, the seawater level becomes elevated. Underestimation of the seawater level during a storm can lead to unacceptable outcomes such as coastal inundation, ineffective coastal planning, and failure of coastal structures. This research derived 11 local relationships between the wind speed and elevated water levels along The Gulf of Thailand. Data during 2001–2014 on recorded water level, predicted water level, and corresponding wind speed were gathered from the responsible governmental departments. The differences between the predicted and the measured water levels were coupled with the wind speed recorded at the same time. Four types of relationship were investigated: linear, logarithmic, exponential, and quadratic. The relationship with the highest value of the coefficient of determination was selected for each site. It was found that, for all stations, the relationships between the wind speed and the elevated water level were quadratic. The best-fitting equation and the 95% upper prediction interval were derived for each station to use as a tool for coastal management and design objectives.

Assessment of complex water pollution with heavy metals and Pyrethroid pesticides on transcript levels of metallothionein and immune related genes

Alteration of immunological function of an aquatic organism can be used as an indicator for evaluating the direct effect of exposure to pollutants. The aim of this work is to assess the impact of complex water pollution with special reference to Pyrethroid pesticides and heavy metals on mRNA transcript levels of Metallothionine and some immune related genes of Nile tilapia (Oreochromas Niloticus). Residues of six heavy metals and six Pyrethroid were assessed in water as well as fish tissues at three different sites of Lake Burullus, located at Northern Egypt. Variations of water physicochemical properties associated with different levels of heavy metals at the three different sections were recorded. Tissue residues of Fe, Mn and Zn, Cu, Ni exceed water levels in contrast to elevated water level of Pb. All assessed Pyrethroids are detected in fish tissue samples with higher concentration (3–42 folds) than that found in water samples especially Cypermethrin. Significant down-regulation of expression levels of metallothionein (MT) at the three sections of the lake was observed. The expression of immune related genes (IgM) and inflammatory cytokines (TNF, IL.8 and IL.1) were affected. IgM and TNF were significantly down-regulated at eastern and western section of the lake; meanwhile the expression of IL8 is down regulated at the three sections of the lack. IL1 was significantly up-regulated at eastern and middle sections.We conclude that, variable gene expression of MT and immune-related genes at the three sections of the lack impose different response to complex water pollution in relation to variable aquatic environment.

Groundwater Engineering in an Environmentally Sensitive Urban Area: Assessment, Landuse Change/Infrastructure Impacts and Mitigation Measures

A rise in the shallow unconfined groundwater at a site in Australia is causing water logging of the underground facility in the affected area. Realizing this problem, a study was conducted to identify the source of water that is causing the rise and to develop an implementation and operation plan of the mitigation (dewatering system). Modelling was undertaken using MODFLOW-SURFACT code, within the framework of Visual MODFLOW, to assess the spatial and temporal groundwater level at the site. The study undertaken incorporates compilation and assessment of available data, including a list of factual information reviewed, development of a conceptual groundwater model for the site and modelling of the pre and post development conditions. The outcomes of the assessment indicate water level rises due to the construction of the embankment are likely less than 0.12 m and changes in land, such as affected area burial, may change aquifer characteristics more significantly than the embankment. It is concluded that the elevated groundwater levels in the affected area are most likely a result of above average rainfall since 2007 and long term cumulative land use changes. The embankment construction is just one of many land use changes that have occurred both within and surrounding the affected area and likely only a minor contributor to the elevated water levels. Greater contribution may be attributed to re-direction of the natural flow paths the railway culvert weir reducing the overland flow gradient and ongoing changes (burial) within the affected area and including the embankment. The model findings gives answers on what factors may be/are causing/contributing to, the higher than usual groundwater levels in the study area. A combination of drainage and/or pumping (dewatering system) is suggested as a solution to overcome the problem of rising groundwater levels at the site. Further, the model output can aid in assessing mitigation options, including horizontal drainage networks and pumping to control for the rising water table conditions in the area, depending on the level of treatment and pathogenic criteria.

Coastal resilience and vulnerability: storm impacts, extreme weather and regional variability in the UK, winter 2013–14

ABSTRACTThe winter of 2013–14 brought extreme storminess to the UK. Monthly rainfall was over 200% of the 1981–2010 average. The damage was considerable, affecting landforms, habitats, societies and infrastructure. Over that winter there were several high-magnitude storms, occurring at very closely spaced time intervals, which were particularly devastating in the west and south-west of the UK. Conversely, in the east a single extreme storm, which occurred on 5 December 2013, did most of the damage. This article highlights how new technologies are being used to quantify some of the key coastal impacts of such events. The data collected support the unevenness of the impact of the storms on the shorelines at different locations around the UK. Storms had a far-reaching and devastating impact along south-west coastlines because these coasts are wave-dominated and every storm included high magnitude waves. However, the east coast shorelines, in particular in East Anglia, are tide-dominated and take a special combination of circumstances to generate the largest impacts. The storm on 5 December 2013 generated elevated water levels in the sea, reaching even greater elevations than the notorious storm of 31 January 1953, where lives were lost. With large waves adding to the impact of high water levels, effects were felt around the whole of the coast of East Anglia. Enhanced forecasting capability and strengthened coastal defences meant that no lives were lost. However, future sea level rise and changing storm tracks may bring even greater coastal devastation; therefore, we need to be prepared to develop new strategies for forecasting, early warning and evacuation planning.

DEVELOPMENT OF A FLOOD RISK ASSESSMENT MODEL FOR A BRAIDED RIVER SYSTEM

The aim of this study is to construct a modeling system that will assist flood risk management strategies in a coastal plain braided river system. The model configuration consists of a hydrodynamic model (ADCIRC) of the river basin that receives tidal forcing at the open boundary and river discharge forcing at upstream flux boundary. An unstructured mesh model resolving the Pearl River channels at higher resolution from the coastline to approximately 75km inland to upstream reaches of the river has been constructed. The modeling system produces water levels and currents throughout the Lower Pearl River Basin. Initial sensitivity analysis efforts on the channel model include consideration of low-flow, average-flow, and high-flow scenarios. Model results were found to be slightly sensitive to slope of river channels and bottom friction to control stability in predictions. The model results were shown to be highly sensitive to the bathymetry of the model that controls the discharge capacity of the narrow river channels and the channel model resulted in elevated currents and water levels under high flow conditions. A channel discharge capacity analysis was conducted and the results showed the need to construct a floodplain mesh around the channel model with more realistic bathymetry and topography so that the flooding scenarios could be modeled with wetting and drying capability of ADCIRC. An initial attempt to develop such a floodplain mesh has been made with preliminary results and more comprehensive validation of the developed floodplain modeling system will extend to reproducing events associated with the historical Hurricane Isaac that impacted the region in 2012. This modeling system will provide an important tool to decision makers that could be used in future flood risk management and mitigation efforts.

Role of continental shelf on non-linear interaction of storm surges, tides and wind waves: An idealized study representing the west coast of India

The study reports role and dependence of continental shelf geometry on the non-linear interaction of storm surges, tides, and wind waves. As a case study, the shelf geometry representing the west coast of India is considered and numerical simulations are executed using the standard representation of a tropical cyclone. The idealized experiments assume the west coast of India as a straight coastline with varying continental shelf width ranging from 35 km in the south to 330 km in the north. For the experiments, ADCIRC model in standalone mode and coupled ADCIRC+SWAN are used by considering 13 idealized cyclone tracks covering the study domain. It is noticed that an amplification of peak storm surge of ∼12 cm for every 10 km increase in the shelf width. During different phases of the tide, the surge-wave interaction modifies the water level elevation and its occurrence as the tidal range increases towards north. The interaction of tides on surges and wind waves is observed maximum at low-tide and minimum at flood tide over the wide shelf regions. In general, the non-linear interaction is found to be 15%–20% for any cyclone track or tidal phase. The wave setup caused by wind waves is marginally varies with change of amplitude and phase of the tide, however, its profile is significantly modified, particularly over the wider shelf widths.

Barrier Island Morphological Change by Bay-Side Storm Surge

AbstractBarrier island overwash and breaching are caused by inundation from ocean storm surge and waves or from elevated levels of bay water. According to numerical simulations, a developed barrier...

Doubling of coastal flooding frequency within decades due to sea-level rise

Global climate change drives sea-level rise, increasing the frequency of coastal flooding. In most coastal regions, the amount of sea-level rise occurring over years to decades is significantly smaller than normal ocean-level fluctuations caused by tides, waves, and storm surge. However, even gradual sea-level rise can rapidly increase the frequency and severity of coastal flooding. So far, global-scale estimates of increased coastal flooding due to sea-level rise have not considered elevated water levels due to waves, and thus underestimate the potential impact. Here we use extreme value theory to combine sea-level projections with wave, tide, and storm surge models to estimate increases in coastal flooding on a continuous global scale. We find that regions with limited water-level variability, i.e., short-tailed flood-level distributions, located mainly in the Tropics, will experience the largest increases in flooding frequency. The 10 to 20 cm of sea-level rise expected no later than 2050 will more than double the frequency of extreme water-level events in the Tropics, impairing the developing economies of equatorial coastal cities and the habitability of low-lying Pacific island nations.

Comparing water-level policies in a boreal reservoir: How wave and ice energy can help maintain walleye spawning habitat

ABSTRACTPapenfuss JT, Cross T, Venturelli PA. 2017. Comparing water-level policies in a boreal reservoir: how wave and ice energy can help maintain walleye spawning habitat. Lake Reserve Manage. 00:00–00.Water levels in reservoirs affect the timing and depth of wave and ice forces that help maintain walleye (Sander vitreus) spawning habitat. We studied how changes in a water-level management policy (“rule curve”) in 2000 affected these forces on 3 lakes of the Namakan Reservoir, a large boreal reservoir on the border of Canada and the United States. The 2000 rule curve increased mean water levels (0.1 m) during open-water seasons and caused a significant increase in the amount of time each year that wave energy over suitable spawning substrates suspended <0.2 mm sediments at known spawning locations (6–18%, P < 0.01). Conversely, a decrease in the mean range (0.7 m) of water-level elevations during winter seasons caused an 11% decrease (P < 0.01) in the interaction of ice with spawning substrates at known spawning locations. However, ice scour still affected those substrate elevations that were used frequently by walleye during typical spawning seasons. Our findings suggest that water-level management is important for maintaining suitable walleye spawning habitats, and that policies can be designed to optimize those habitat conditions.

Evaluation of XBeach performance for the erosion of a laboratory sand dune

A new set of laboratory data is used to investigate the bathymetry change of a steep sand dune exposed to waves and high water levels, and subsequently compared to the results of numerical simulations using XBeach. Bichromatic wave boundary conditions are used to simulate a combined short-wave and long-wave field for two water level elevations corresponding to collision with the dune face, and overwashing of the dune crest. In the collision regime case, episodic slumping due to the undercutting of the dune results in sudden erosional events followed by long periods of wave-driven reshaping at the dune toe. In the overwash regime case, morphological changes are faster and sediment transport rates are higher.The XBeach model was used to simulate wave-driven erosion of the dune at the two water levels observed in the laboratory. The model was not able to precisely recreate the cross-shore spatial variability of significant wave height observed in the experiments, however near-bed wave-orbital and mean current velocities were in good agreement with observations. Following rapid initial adjustment, the model results were in agreement with measured dune morphology at successive times. XBeach was sensitive to several parameters that control the rate of erosion including the critical avalanching slope under water, the threshold water depth and the sediment transport formulation, and performed well after careful selection of the best combination of these parameters. Overall, the model predictions were in better agreement with laboratory observations for dune erosion in the overwash regime case than the collision regime case.

Observations of waves and currents during barrier island inundation

AbstractOverwash and inundation on barrier islands can transport sediment onshore, leading to vertical accretion. These processes could ensure barrier island growth in times of sea‐level rise, but wave and current fields during overwash and inundation are not well understood. Field data of water levels, waves, and currents were collected on a barrier island in the Netherlands to investigate the hydrodynamics during island inundation. Observations show that even in shallow water depths (&lt;0.5 m) wave energy was not completely dissipated as waves propagated from the North Sea onshore. Additionally, locally generated wind waves entered the field area from the Wadden Sea and propagated offshore. Infragravity waves were an important part of the wave field, particularly onshore of the beach crest. They were observed to be onshore progressive and displayed a bore‐like shape when water depths were shallow. Wave breaking was the dominant dissipation mechanism for high‐frequency waves as well as for infragravity waves, which is in agreement with prior research on infragravity wave energy dissipation on mild sloping (closed‐boundary) beaches. A large‐scale offshore directed water‐level gradient between the Wadden Sea and the North Sea side, caused by elevated water levels in the Wadden Sea during the storms, frequently drove an offshore flow if it was large enough to exceed the cross‐shore gradient due to wave setup. In addition, elevated water levels in the Wadden Sea decreased current velocities due to a decrease in water‐level gradients. This study highlights the influence of back‐barrier processes on the hydrodynamics during inundation.

Tidal propagation and its non-linear characteristics in the Head Bay of Bengal

The Head Bay of Bengal is highly vulnerable to flooding events caused due to monsoons, cyclones and sea-level rise, owing to its funnel-like shape, high tidal range, presence of numerous river drainage systems, low-lying topography, and shallow bathymetry. Tides dominate the hydrodynamic behaviour and coastal processes in this region and its propagation is quite distinct. The present study uses ADCIRC hydrodynamic model customized for the Head Bay of Bengal, discretized using unstructured finite elements and validated against limited available observations in this data sparse region. The water-level elevations derived from ADCIRC simulation was used to understand the pattern of non-linear tidal propagation with respect to complex coastal geomorphology prevalent in this region. The study finds a marginal amplification of diurnal tide, nearly double amplification of semi-diurnal components, and existence of a degenerate amphidromic point near Meghna delta consistent with previous studies. The spatial and temporal variability of tidal spectral components were examined by applying the techniques of wavelet, harmonic, and time-series analysis at various locations. Maximum amplification of tides occurs at the head of the bay, along a zone enclosing the mouth of tidal inlets; and for regions northward, the tides decay with progressively increasing phase lags. The study signifies dominance of a forced fortnightly tide and tidal asymmetry leading to flood-dominance in the rivers Hooghly, Meghna, and Tetulia. The non-linear properties of tides have been elucidated, and their origin and spatio-temporal variability in these riverine systems were further investigated. Shallow depth and sharp depth gradients were discerned to be the important conditions for the origin of non-linear components. It has been deduced that non-linear tides are generated in regions where propagating tides are accumulated, and amplified in regions where they are funneled. A study of tidal energetics show that maximum rate of tidal energy dissipation is deep inside the rivers at head of the bay. The spatial variability analysis of tidal form factor shows an overall semi-diurnal dominance in the Head Bay.

Rapid attribution of the August 2016 flood-inducing extreme precipitation in south Louisiana to climate change

Abstract. A stationary low pressure system and elevated levels of precipitable water provided a nearly continuous source of precipitation over Louisiana, United States (US), starting around 10 August 2016. Precipitation was heaviest in the region broadly encompassing the city of Baton Rouge, with a 3-day maximum found at a station in Livingston, LA (east of Baton Rouge), from 12 to 14 August 2016 (648.3 mm, 25.5 inches). The intense precipitation was followed by inland flash flooding and river flooding and in subsequent days produced additional backwater flooding. On 16 August, Louisiana officials reported that 30 000 people had been rescued, nearly 10 600 people had slept in shelters on the night of 14 August and at least 60 600 homes had been impacted to varying degrees. As of 17 August, the floods were reported to have killed at least 13 people. As the disaster was unfolding, the Red Cross called the flooding the worst natural disaster in the US since Super Storm Sandy made landfall in New Jersey on 24 October 2012. Before the floodwaters had receded, the media began questioning whether this extreme event was caused by anthropogenic climate change. To provide the necessary analysis to understand the potential role of anthropogenic climate change, a rapid attribution analysis was launched in real time using the best readily available observational data and high-resolution global climate model simulations. The objective of this study is to show the possibility of performing rapid attribution studies when both observational and model data and analysis methods are readily available upon the start. It is the authors' aspiration that the results be used to guide further studies of the devastating precipitation and flooding event. Here, we present a first estimate of how anthropogenic climate change has affected the likelihood of a comparable extreme precipitation event in the central US Gulf Coast. While the flooding event of interest triggering this study occurred in south Louisiana, for the purposes of our analysis, we have defined an extreme precipitation event by taking the spatial maximum of annual 3-day inland maximum precipitation over the region of 29–31° N, 85–95° W, which we refer to as the central US Gulf Coast. Using observational data, we find that the observed local return time of the 12–14 August precipitation event in 2016 is about 550 years (95 % confidence interval (CI): 450–1450). The probability for an event like this to happen anywhere in the region is presently 1 in 30 years (CI 11–110). We estimate that these probabilities and the intensity of extreme precipitation events of this return time have increased since 1900. A central US Gulf Coast extreme precipitation event has effectively become more likely in 2016 than it was in 1900. The global climate models tell a similar story; in the most accurate analyses, the regional probability of 3-day extreme precipitation increases by more than a factor of 1.4 due to anthropogenic climate change. The magnitude of the shift in probabilities is greater in the 25 km (higher-resolution) climate model than in the 50 km model. The evidence for a relation to El Niño half a year earlier is equivocal, with some analyses showing a positive connection and others none.

Application of the TDR technique for the detection of changes in the internal structure of an earthen flood levee

Failures of earthen flood protection structures cause enormous material loss. Despite this, in the majority these are structures that were built decades ago. As an example, in Poland, the time of operation of approximately three quarters of existing levees and embankments is over 40 years. A similar situation exists in many other European countries. In the period 1998–2009 the economic losses caused by floods amounted to over 60 thousand million Euro. This accounts for approximately one third of the total losses caused by environmental factors. Ruptures of embankments or levees occur as a result of long-lasting elevated water levels in rivers, and such events are always preceded by changes in their internal structure. Such changes cannot be detected from the outside. This paper presents a new method, never used before, for the determination of changes in the internal structure of the body of a levee. The dynamics of the displacements is described by means of new mathematical formulae. The input data necessary for their application include the dynamics of changes in the value of volumetric moisture that is measured with a freely selected short time step by means of the time-domain-reflectrometry technique. The formulae were created on the basis of hitherto unnoticed and uninterpreted drops in moisture a moment before and a moment after the saturation of inner spaces of the levee body. The results obtained from calculations were compared with data from measurements on a physical model of a levee. The settlement values calculated using the method proposed are convergent with those of the true settlement. The maximum relative error was as low as 19%. The method proposed permits the location of changes in the internal structure of a levee before its rupture. Its application is the main component of a system of early warning against floods.

Underkeel Clearance Reliability Model for Dredged Navigation Channels

This paper presents a reliability measure for selecting marine navigation channel maintenance depth. Resource constraints have resulted in dredging requirements outpacing the funds available to the U.S. Army Corps of Engineers to perform navigation channel maintenance dredging, but navigation managers lack a method to objectively select maintenance depth alternatives to authorized project depths. The reliability of a navigation channel can be determined as the probability that a vessel's net underkeel clearance is greater than or equal to 0. Net underkeel clearance was hindcast from underkeel clearance contributors that include sailing draft, water level, bathymetric elevation, vessel squat, and wave response. This method was tested in Charleston Harbor, South Carolina, with an authorized depth of 45 ft (13.7 m). The harbor includes two-way container, tanker, roll on–roll off, and passenger traffic with maximum drafts exceeding design depth. Vessel squat in transit is calculated on the basis of vessel speed, obtained from Automatic Identification System (AIS) data and a representative block coefficient based on vessel size and type. This study used archival AIS data, bathymetric surveys, observed water level elevations, and information collected by vessel pilots to calculate net underkeel clearance of vessel transits through each dredged location within the harbor in 2011. It was determined that channel reliability ranged from 98.7% to 100%. Channels with 100% reliability had minimum net underkeel clearance between 1.0 ft (0.3 m) and 8.3 ft (2.5 m). The approach provides a potential method to select maintenance depth alternatives to authorized channel depths that may result in maintenance cost savings that arise from avoided dredging and associated material management costs.

Analysis and Application of River Surface Line in Hilly Area based on Hec-ras Model

For example—Cixian Fuyang River Regulation Project. Due to the character that Fuyang River is located in hilly areas of Cixian, we use the Hex-ras software to calculate the status of the river water surface line for the goal of determining the final treatment plan. We maintain the present situation of the river channel design as principle, select the most appropriate pushed water level and roughnessas the basic, and we combine the classification calculation of crossing structures of backwater and the encryption calculation section to get the more accurate result. We compare the water level elevation and the calculation of cross strait, analyze the design parameters, calculate repeated the water line section, analyze the rationality of the design plan, and then finally determine the applicability of Hex-rac software in the large continuous variation of cross section of embankment of river river surface line.