DOI: 10.4236/gep.2019.73011 199 Journal of Geoscience and Environment Protection Since the annual precipitation in Shanxi Province is mainly concentrated in the flood season, the total precipitation in all flood seasons can generally reflect the drought and flood conditions in the current year. In order to understand the re- lationship between the short-term heavy rainfall in the flood season in Shanxi Province and the flood and drought characteristics in the flood season, Figure 8 shows the Shanxi Province. The average annual distribution of total precipita- tion during the flood season, and the correlation coefficient between the total precipitation of each station in each flood season and the number of short-term heavy precipitation in the same year. It can be seen from Figure 8(a) that the average total precipitation in the flood season in Shanxi Province is between 175 and 460 mm, showing a distribution of less south to north and less in east and west, similar to the distribution in Figure 7(f). The correlation coefficient be- tween the average total precipitation in the flood season in Shanxi Province and the average short-term heavy precipitation station in the 36 years was calculated to be 0.74, and the significance test was passed through 0.001. In Figure 8(b), the annual total precipitation in each station shows a good correlation with most of the short-term heavy precipitation stations in the same year. Only the northern
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Abstract. We explore the memory properties of catchments for predicting the likelihood of floods based on observa- tions of average flows in pre-flood seasons. Our approach assumes that flood formation is driven by the superimpo- sition of short- and long-term perturbations. The former is given by the short-term meteorological forcing leading to in- filtration and/or saturation excess, while the latter is origi- nated by higher-than-usual storage in the catchment. To ex- ploit the above sensitivity to long-term perturbations, a meta- Gaussian model and a data assimilation approach are im- plemented for updating the flood frequency distribution a season in advance. Accordingly, the peak flow in the flood season is predicted in probabilistic terms by exploiting its dependence on the average flow in the antecedent seasons. We focus on the Po River at Pontelagoscuro and the Danube River at Bratislava. We found that the shape of the flood fre- quency distribution is noticeably impacted by higher-than- usual flows occurring up to several months earlier. The pro- posed technique may allow one to reduce the uncertainty as- sociated with the estimation of flood frequency.
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This research was conducted in the upstream watershed of the Mae Yom Irrigation Project, which was located in the Upper Yom River Basin in Phrae Province, Thailand. The most common troub- lesome in this area is flood and drought and leads to poor water management by difficult river flow forecasting to an existing large weir without upstream dam. The Soil And Water Assessment Tool (SWAT) model was applied for the simulation of the hydrological system and predicting the daily river flow to the upstream weir during flood season in 2006 and 2011 as for simulating and comparing with observed data. The results were fitted to the observed data with Nash and Sut- cliffe efficiency (NSE) of −0.65, and root mean square error (RSME) of 228.0 whereas the mean in- flow discharge during wet season in both years was 173.3 cubic meters per second, respectively.
The Lanmucuo River is a typical meandering river covered by dense meadow. Although typically characterized by large bends in a flat valley, mid-channel gravel bar covered by herbs sometimes form at the apex of bends (Fig. 2 R3a). The meandering channel and bars are very stable because of low sediment supply in the flood season and good vegetation cov- erage. The tight root-soil complex on concave banks inhibits flow scour. When cantilevered bank failures do occur, slump blocks restrict further erosion of the bank. Grass develops on the point bars of convex banks. When the overbank flow sub- merges the point bar, the herbaceous vegetation can increase flow resistance and promote fine sand deposition (Fig. 9), thereby maintaining channel geometry with a relatively low migration rate. Growth of herbs on mid-channel bars (Fig. 2 R3a) helps to increase the flow resistance and trap fine sedi- ment, facilitating channel stability.
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Slight acidic pH in post flood season might be due to inputs in the form of organic acids, chemicals, fertilizers from punctual and non punctual sources (Rodriguez and Arauj, 2012). Higher dissolved oxygen can be attributed to low biological activity and water turbulence as supported by earlier workers (Vass et al., 1977; Qadri et al., 1981). Calcium and Magnesium concentrations showed trends similar to that of total hardness, their concentration increase downstream. Significant concentrations of calcium and magnesium might be due to their uptake by the plants in the formation of chlorophyll- prophyrin metal complexes and in enzymatic transformation (Wetzel, 1975). The increased values of chloride in post flood season depicted the anthropogenic influence on the river. The ionic composition of water varied in close relationship with the spatial characteristics in catchment area of river Jhelum. The increased electrical conductivity in the middle stream showed a close relationship with the anthropogenic pressure in urban stretch of the river (Reid, 1961). Decrease in temperature of water in post flood season may be due to meteorological change, decline in air temperature and erratic rainfall at higher altitudes of the state of Jammu and Kashmir (Azizullah et al., 2011; Baqir et al., 2012). In general, most of the physico- chemical parameters increased significantly in post flood season which can be clearly attributed to the phenomenon that flood water entered in open sources and flushed away everything from agricultural fields, settlements, commercial areas, domestic and industrial areas located around river Jhelum (Arnone et al., 2007; Biggs et al., 2011; Badruzzaman et al., 2012; Baqir et al., 2012).
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Abstract. With the increasing trend of water-related disasters such as floods and droughts resulting from climate change, the integrated management of water resources is gaining importance recently. Korea has worked towards preventing disasters caused by floods and droughts, managing water resources efficiently through the coordinated operation of river facilities such as dams, weirs, and agricultural reservoirs. This has been pursued to enable everyone to enjoy the benefits inherent to the utilization of water resources, by preserving functional rivers, improving their utility and reducing the degradation of water quality caused by floods and droughts. At the same time, coordinated activities are being conducted in multi-purpose dams, hydro-power dams, weirs, agricultural reservoirs and water use facilities (featuring a daily water intake of over 100 000 m 3 day −1 ) with the purpose of monitoring the management of such facilities. This is being done to ensure the protection of public interest without acting as an obstacle to sound water management practices. During Flood Season, each facilities contain flood control capacity by limited operating level which determined by the Regulation Council in advance. Dam flood discharge decisions are approved through the flood forecasting and management of Flood Control Office due to minimize flood damage for both upstream and downstream. The operational plan is implemented through the council’s predetermination while dry season for adequate quantity and distribution of water.
Each of these types of flood protection and other flood-exposed SSCs are associated with diverse types of failure modes. For example, passive flood protection features (exterior, incorporated, and temporary) may be subject to overtopping as well as structural failure modes as a result of hydrostatic and hydrodynamic loads (e.g., wind waves, currents) and debris. Moreover, certain types of barriers (e.g., external embankments) may be vulnerable to geotechnical failure modes such as slope instability and internal erosion. In addition to structural failure modes, active flood protection features may be subject to mechanical failures (e.g., failure to start or failure to run). Other flood-exposed SSCs may be subject to failure as a result of inundation or spray (usually, it is assumed that equipment submerged by the flood waters and not designed for submerged operation will not be able to perform its safety function, Ref. ) as well as many of the failure modes that are relevant for flood protection (e.g., a flood-exposed SSC may fail as a result of debris impacts). The large diversity of SSCs and the associated failure modes implies that multiple types and multiple levels of complexity will need to be addressed in fragility models developed to support external flooding PRAs.
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Flash floods are a common, but it is not easy to esti- mate its environmental features. A lack of accurate en- vironmental data creates much of the uncertainty associ- ated with flash flooding events. In addition to limiting the understanding of hydrological processes, human use and development in a region cause number of problems. Extreme events often exert a disproportionately large effect on the environment, for larger than that associated with the more commonplace typical events, and are those most associated with hazards to humans . A major concern with flash flooding is the development within a very short period of time. Human life and infra- structures are under a major threat of flash flooding. The lack of understanding sometimes compounds problems of flooding, with settlement, road and other structures inappropriately located and designed relative to the flood risk .
Flood, a volume of water enters a certain area and it cannot be discharged quickly enough through the river channels proper. As a consequences thereof, water level rises until bankful stage is reached, then bank overspill starts and flooding occurs. Throughout the world floods and flooding occurs as natural phenomena which, in most cases, not much appreciated by the people living in the affected areas. Consequently, flood management and flood control are introduced in many places to prevent the negative consequences of the flood. Sustainable development aims the sustained improvement in the living conditions of all citizens in an environment characterized by equity, security, and freedom of choice. This paper presents the study of sustainable flood management describing the interplay between floods and development process. It takes a look at traditional flood management practices, identifies the major challenges for managers and decision-makers dealing with sustainable development. GENERAL METHODOLOGY
Natural disasters are occurred at every part o f the world. Among the natural disasters, floods are causing enormous economic losses o f US $ 18 billion and about 6,000 people death annually for last 30 years. All this numbers are registered into The OFDA/CRED International Disaster Database. Similar problem occurs in Malaysia annually and also cause huge economic losses in which the average annual flood damage is as high as RM 100 million (US $ 33 million). This flood damage cost is acquired from The OFDA/CRED International Disaster Database. These flooding have caused considerable damage to highways, settlement, agriculture and livelihood. Generally, flood management approaches are used to reduce flood damage or prevent damage can be divided into structural and non-structural measures .
flooding. Although survey-based studies have examined links between public perceptions of hot weather and climate change beliefs, relatively little is known about people’s perceptions of changes in flood risks, the extent to which climate change is perceived to contribute to changes in flood risks, or how such perceptions vary by political affiliation. We discuss findings from a survey of long-time residents of Pittsburgh, Pennsylvania (US), a region that has experienced regular flooding. Our participants perceived local flood risks as having increased and expected further increase in the future; expected higher future flood risks if they believed more in the contribution of climate change; interpreted projections of future increases in flooding as evidence for climate change; and perceived similar increases in flood risks independent of their political affiliation despite disagreeing about climate change. Overall, these findings suggest that communications about climate change adaptation will be more effective if they focus more on protection against local flood risks, especially when targeting audiences of potential climate sceptics.
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The global environmental and social changes experienced in cities have made it necessary for policy-makers to reconsider and perhaps re-conceptualize the policy making process. Specific to this research, climate change has made it difficult to predict the extent of extreme future weather conditions. The gravity of the situation increases in delta and coastal cities that are vulnerable to floods. For a long time strategies used to mitigate against floods exclusively involved hard- engineering approaches such as building and fortification of dykes due to the stability of weather conditions, essentially precipitation and global temperatures. The times have now changed and interventions to mitigate floods increasingly have to be flexible to adapt to weather uncertainties. In addition policies need to incorporate varied socio-economic aspects, so as to be sustainable and resilient. (The history of this change in water governance from hard to soft is described in Chapter 3 of this thesis). Thus flood mitigation policy now has to incorporate varied sectors, levels of administration and temporal scale. Invariably, new policy is to be soft and flexible, hence adaptive (Walker, 2001).The vital role of adaptive policy development and implementation is introduced in the succeeding sections of this introductory chapter, and thereby establishing the rationale leading up to this research.
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Our research attempted to present an overview of the impacts of the “live with water” approach to flood management , which incentivizes local stakeholders to treat water as a resource instead of a threat  by creating income generating activities and support local flood management. Although the BRACED-LWW project was implemented in a very short period of time (a total of approximatively 14 months), some significant impacts could already be observed on urban flood resilience. By physically protecting households from floodwater, the drainage infrastructures led to a clear reduction of households’ flood exposure entailing an improvement of their resilience. These changes were most particularly visible on households’ absorption capacity, with improvements in housing infrastructures, health conditions, living conditions, mobility, and leisure periods. The LWW project has also had a visible influence on producing and diffusing information about flood risks and about the measures to be taken in order to anticipate disaster, with the dissemination of information through TV and newspapers being the most important components for improving anticipatory capacity at households’ level. These results clearly emphasize the importance of addressing smaller flood events in complement to other large scale and primary drainage infrastructures .
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Figure 8: Typical section of river bank and flood zones However, most urban rivers are modified in one way or another and the areas protected by flood defences may be shown on flood probability maps. Flood defences may be located at any position and at any elevation, but typically would be located at the edge of a channel, aflood plain or boundary between the high and medium probability flood zone as illustrated in Figure
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Chandran et.al, (2006), has used the Airborne Synthetic Aperture Radar (ASAR) images in mapping the flood inundation and causative factors of flood in the lower reaches of Baghmati river basin for the period July– October 2004. Integration of the flood inundation layer and land cover layer derived from LISS III data indicate that 62 percent of the agricultural area was inundated. Floodwater drained faster in the left bank, whereas it was slow in the right bank. The Digital Elevation Model of the area shows that the flood-prone right bank of the Baghmati River is a topographic low sandwiched between Kosi and BurhiGandak highs (mega fans). Area under flood inundation for various land cover classes has been shown comparative bar graph. Spatial maps such as fluvial geomorphology of the study area, drainage configuration of Baghmati river during pre-flood, flood and post-flood, Transverse spatial profiles across Kosi–Ganga transect, Bhirkhi–Ranka transect and Bharath– Bachhauta transect and, Longitudinal spatial profiles along (a) Chanhanadi and (b) under fit channel of Baghmati, and difference image (pre-post) showing flooding from tributaries and embankment failure has been prepared by them. In this study, they observed that the right bank of the Baghmati river undergoes frequent flooding due to topography, channel morphometry and discharge characters. The embankment constructed along the course (Baghmati and BurhiGantak) is found to impede therecession of floodwater.
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obtained from the USGS gaging station on the Neuse River near Fort Barnwell, NC (#02091814) (Table 4). The value from the DEM at Ft. Barnwell (1.770 m) was removed from the gage height values to account for removal of slope trend in the REM. In ArcMap, a constant planer raster layer was created (Spatial Analyst toolbox; ERSI, 2011) using the gage height value, then Cut Fill (3D Analyst toolbox; ERSI, 2011) was used to subtract the constant layer from the DEM. The Cut Fill tool is generally used to calculate soil removal or addition for construction, sediment deposition and erosion, or to study areas that become inundated during mudslides (ERSI, 2011). When used, the Cut Fill tool takes areas that need to be filled and makes the volume of that area positive, while areas that need to be cut will be negative for the volume. Here, it has been adapted to compute flood and wetland water volumes for use in flux
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practitioners was largely positive, affirming and constructive. The overriding feedback in four of the municipalities was that the research presented was important and potentially useful to them, though it contained minor flaws that could be fixed, in part, with local input. Practitioners from one municipality were critical of the research approach and felt that it was not applicable in their community. Many practitioners were excited to have an outside group of researchers address a topic that they felt was under-recognized in their community. One participant responded that “with all we’ve talked about with hazards and climate change adaptation, we haven’t talked about the people who are in the places we think are exposed” (City of Vancouver staff). Overall, there was a fairly high level of agreement with the variables selected to indicate social vulnerability to flood hazards. Some practitioners suggested other variables that had not been included in the index. When presented with the total score map, the most common critique received was similar to “these variables weighted the same doesn’t make sense” (District of North Vancouver staff). The idea that a variable like low income, for example, was weighted equally to a variable like having a university education was problematic for many practitioners. They suggested that the variables that are more indicative of social vulnerability should be weighted more heavily in the index than other, less important variables.
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Possessing many common natural features, the rivers of the considered basin differ in some local features, significantly and visually shown in their water regime. The surface water of the rivers of the basin is formed only during the thawing of snow cover. Thus, for example, the rivers of all three mentioned groups have the delivery prevail- ing snow framing the main phase of water regime – spring flood.
Flood is common problem at the zone around the water reservation. Nevertheless, at the watering zone always faced the lack of water supply during the drought season. Hopes by using the automatic control, this problem can be solved. The manual systems need the full experience person in charge to control the gate opening and closing because every earliest or late action taken will cause the large damage in critical cases. With this control system, the water reservation controlling is easier and more accurate.
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Figure 3-1. Location of sites within the flood plume water quality monitoring for the 2010-11 wet season. .................................................................................................................................................. 13 Figure 3-2: Plume sampling sites where passive samplers were deployed during a major flood event in the Fitzroy region. ............................................................................................................................. 14 Figure 3-3: MODIS satellite image (4 January 2011) of the Burdekin River flood plume, with the location of the three sampling transects overlain. The sampling site in the freshwater part of the Burdekin River at Inkerman is also shown. The white patches over water (adjacent to the coast) are clouds. Source: Bainbridge et al., (2012). ............................................................................................. 16 Figure 3-4.Location and geographical information for the water quality sites sampled in the Wet Tropics (Tully and Russell-Mulgrave Rivers) (2010-11). ........................................................................ 17 Figure 3-5: Process of calculating the WQI for each site sampled in the 2011 season. WQI can also be scaled up to be at the transect and regional level. ............................................................................... 19 Figure 4-1. Cyclone Yasi passage as it moved across the GBR and approached landfall on 2 February 2011. Source: Bureau of Meteorology (www.bom.gov.au). ................................................................. 22 Figure 4-2: Aerial imagery of the area affected by Cyclone Yasi,. (a) pre Cyclone yasi, (b) two days prior to Cyclone Yasi, (c) during Cyclone Yasi and (d) post Cyclone Yasi. Note the scouring and turbid conditions throughout the central GBR
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