### Abstract

A river bifurcation, can be found in, for instance, a river
delta, in braided or anabranching reaches, and in
manmade side channels in restored river reaches.
Depending on the partitioning of water and sediment
over the bifurcating branches, the bifurcation develops
toward (a) a stable state with two downstream branches
or (b) a state in which the water discharge in one of the
branches continues to increase at the expense of the
other branch (Wang et al., 1995). This may lead to
excessive deposition in the latter branch that eventually
silts up. For navigation, flood safety, and river
restoration purposes, it is important to assess and
develop tools to predict such long-term behavior of the
bifurcation.
A first and highly schematized one-dimensional model
describing (the development towards) the equilibrium
states of two bifurcating branches was developed by
Wang et al (1995). The use of a one-dimensional model
implies the need for a nodal point relation that describes
the partitioning of sediment over the bifurcating
branches. Wang et al (1995) introduce a nodal point
relation as a function of the partitioning of the water
discharge. They simplify their nodal point relation to the
following form: s*=q*k
, where s* denotes the ratio of
the sediment discharges per unit width in the bifurcating
branches, q* denotes the ratio of the water discharges
per unit width in the bifurcating branches, and k is a
constant. The Wang et al. (1995) model is limited to
conditions with unisize sediment and application of the
Engelund & Hansen (1967) sediment transport relation.
They assume the same constant base level for the two
bifurcating branches, and constant water and sediment
discharges in the upstream channel. A mathematical
stability analysis is conducted to predict the stability of
the equilibrium states. Depending on the exponent k they
find a stable equilibrium state with two downstream
branches or a stable state with one branch only (i.e. the
other branch has silted up). Here we extend the Wang et
al. (1995) model to conditions with gravel and sand and
study the stability of the equilibrium states.

Original language | English |
---|---|

Pages | 94-94 |

Number of pages | 1 |

Publication status | Published - 2017 |

Event | RCEM2017 Back to Italy: 10th Symposium on river coastal and estuarine morphodynamics - Trento-Padova, Italy Duration: 15 Sep 2017 → 22 Sep 2017 |

### Conference

Conference | RCEM2017 Back to Italy |
---|---|

Country | Italy |

City | Trento-Padova |

Period | 15/09/17 → 22/09/17 |

## Fingerprint Dive into the research topics of 'A gravel-sand bifurcation: a simple model and the stability of the equilibrium states'. Together they form a unique fingerprint.

## Cite this

Schielen, R. M. J., & Blom, A. (2017).

*A gravel-sand bifurcation: a simple model and the stability of the equilibrium states*. 94-94. Abstract from RCEM2017 Back to Italy, Trento-Padova, Italy.