Performance Test for Selected Total Bed Material Load Equations with High Gradient River Data

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Flood Inundation Analysis Using HEC-6 And Arcview GIS 3.2a

An integration procedure namely AVHEC6.avx has been created between Arc View GIS 3.2a and HEC-6 hydraulic model to perform flood inundation analysis. The procedure was tested using hydraulic and hydrological data for Pari River channel and floodplain with the reach approximately 4 km long

Influential Parameters for Sediment Transport Prediction in Headwater Streams

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Sediment transport modeling and flood risk mapping in Geographic Information System (GIS)

Most computer models used in the flood risk analysis of rivers have inadequate functions in its spatial analytical capabilities and without sediment transport simulation capacity or suitable equations to represents correctly in-situ hydraulic processes (Sinnakaudan et al., 2001, Sinnakaudan, 2003). Further more, the consistent deficiencies of these models are their inability to connect the information describing the water profiles with their physical locations on the land surface. This is where a Geographic Information System (GIS) becomes a valuable tool in spatial modeling for engineers, planners and geoscientist (Burrough, 1998; Sinnakaudan et.al, 2003)

Integrating Structural and Non-structural Flood Management Measures for Greater Effectiveness in Flood Loss Reduction in the Kelantan River Basin, Malaysia

The state of Kelantan in Malaysia is a flood-prone state exposed to seasonal Monsoon rains that bring seasonal floods resulting in significantly losses. Flood management in the state is modelled after the country’s predominant government-centric top-down approach focused on flood-control technologies via structural measures such as multi-purpose dams, levees, embankments, tidal gates, diversion channels and others. These structural measures do not engage the public who fail to understand the measures leading to lack of confidence, misunderstanding and mistrust. This results in ineffectiveness of the measures leading to greater flood losses. In contrast, local communities are familiar with non-structural measures which they have long used to adapt to floods. These measures are also relatively simple, cost-effective and easily implementable over a short period of time. Both measures, however, must engage the public/victims in all phases of the flood disaster cycle. Balancing both types of flood management measures is the key to more effective management. A combination of structural and non-structural measures is the way forward for Kelantan State as it ensures that government structural measures are effectively supported by public-engaged non-structural measures

Performance of “reference” critical shields stress and bed-load formular using different particle size representative: a case study for coarse bedded streams

Surface bedform in the form of immobile clast is deduced to be presence at micro-scale. Immobile clast is believed to modify the flow field and provides sink and source for incoming sediment particles. The dynamics of bed load rate in the presence of immobile clast are always puzzling due to wide range of particle size and presence of roughness elements. Alterations to the bed compared to a non-organized state come largely from hydrodynamic hiding or sheltering effects and modification of grain pivot angles. These grain-scale arrangements and trapping or sourcing of sediment occurs at a very localized level and may dynamically change through the course of a flood event. This paper attempts to look at the performance of “reference” critical Shields stress and bed load formula using different particle size representative. The immobile clast provides hiding function and has been incorporated in the bed load derivation formula. In addition, presence of fine particle at the interstices of immobile clast offers wide ranges of particle size representatives; spanning from surface, subsurface and hybrid distribution. Existing “reference” critical Shields stress is tested against the bed load data using reference transport method and flow competence approach. It seems that the “reference” critical Shields stress using the reference transport approach is far better than the flow competence approach. The performance of Shields stress, however, is very much related to the accuracy of existing bed load prediction. Thus, existing bed load formula of Recking (2010) and Recking (2013) was tested using data at coarse bedded stream. The original 84% percent finer (d84), arithmetic mean size (da), geometric mean size (dg) and representative mean size (dσ) for surface, subsurface and hybrid distribution were used to test the existing bed load equation. It was found that surface distribution performed better than the rest and the use of representative mean size (dσ) can give better estimation than 4% percent finer (d84) in sediment transport calculation