Ecology and Environmental Protection [607692]

Ecology and Environmental Protection
 
 SEDIMENT TRANSPORT MODELING OF MACIOVITA RIVER, ROMANIA,
CARAS SEVERIN COUNTY

Lecturer Dr. Eng. Robert Beilicci1
PhD. Eng. Andrei Armas1
Lecturer Dr. Eng. Erika Beilicci1
1Politehnica University Timisoara, Civil Engineer ing Faculty, Department of Hydrotechnical
Engineering, Romania

ABSTRACT
Study case is situated in Caras Severin County. Every sediment transport model
application is different both in terms of time and space scale, study objectives, required
accuracy, allocated resources, background of the study team etc. For sediment transport
modelling, it is necessary to know the characteristics of the sediment in the river bed. Therefore, it is recommended to collect a number of bed sediment grap samples. These
samples should be analyzed in terms of grain size distribution. To solve theoretical
problems of movement of water in the river Maciovita, it requires modeling of water
flow in this case. Numerical modeling was performed using the program MIKE11.
Advanced computational modules are included for description of flow over hydraulic structures, including possibilities to descri be structure operation. MIKE 11 offers a
variety of options for modelling of sedime nt transport dynamics and morphological
changes in the river bed. Transport models are available for fine, cohesive sediments,
such as clay and silt, non-cohesive sediments, such as sand, gravel and boulders, as well
as mixed sediments. In a morphological model with dynamic feedback between the hydrodynamics, sediment transport and bed level and planform changes, the upstream
sediment transport boundary condition is important. The longer the simulation period is,
the more important the boundary condition is. Basically, two types of boundaries can be imposed: Bed levels or sediment transport rates at the boundary. The former is often
applied, if it can be assumed with good approximation, that the bed level remains the
same at the upstream boundary. The latter is applied, if specification of sediment
transport (e.g. a zero transport) can be done accurately.
Keywords: Hydraulic modeling, roughness of river bed, sediment transport

INTRODUCTION
The right tributary of the Timi ș River, the Maciovi ța brook has a torrential character on
the upstream side, with reduced time of conc entration of the floods, a situation that
favors the erosion of the banks but also the dangerous depth of the valley (Figure 1).
Upstream the base rock formed by hard rocks and marl comes to the surface, the banks
have heights of 3.00-5.00 m, there being the danger of collapse for the houses and the
annexes of the household in Maciova. The s hores are eroded along the entire length,
with the danger of collapsing the communal road on a length of 500 m.

18th International Multidisciplinary Sc ientific GeoConference SGEM 2018
 In the downstream sector, due to the low slope s and the transport of material loose from
the banks of the brook, the abundant vegetation that obstructs the drainage section, there
was a complete clogging of the brook, which favors frequent flooding of the area's households, as well as the devastation of the minor bed. Practically downstream to the
confluence with the Timi ș River, the Maciovi ța streambed changed its course after each
flood, destroying major agricultural land.

Figure 1 Plan view.
The Maciovi ța valley development works are necessary to avoid damages caused by
floods on the territory.
For the arrangement of the Maciovi ța Stream course on the studied sector, works are
foreseen including:
Reprofilation of L = 2000m for transiting the flow rate and stopping the trapezoidal bed
climbing with the base width of 5.00m in the downstream sector of the locality and up
to the confluence with the river Timi ș. The total height of the resulting section for the
level corresponding to the flow rate is h = 1.20m.
Consolidation of shore with gabion boxes L = 1165m- having the section 1.00×1.00x
3.00m, 1.00×1.50×3.0m and gabion mattress of 0.30×3.00×3.00m, made of OB37 Ø16mm steel frame, disposed at 1 , 00m distance and OB37 Ø10mm inside, welded at
0.50m away, mounted on galvanized mesh Ø3.8mm with 40x40mm mesh. The boxes
will be filled with broken stone. The stone will be seated manually in the form of dry masonry. The boxes will bind in all directions with OBØ6 at 0.20cm distance. It will be
applied on both sides of the creek to protect the road, the river construction, the completion of the existing works and the stopping of the material drive phenomenon.
The stone masonry parapet L = 145ml – applie s to the upstream sector in the area of
natural fall with the base rock at the surface and the banks with heights of 0.20-0.50m,
to ensure the height of the calculation.
The elevation of the 1.00 m parapet is made of stone masonry, with a width of 0.40 m
and the slope of the watered surface of 5: 1, and the one from the vertical enclosure. On
the sill coronation there is a 0,10m thick concrete ribbon. The ground foundation is
0.80m deep, the concrete foundation is C8 / 10 with a width of 1.50m. The slope of the
bed is stabilized upstream by means of 7 gabion falls.

Ecology and Environmental Protection
 
 Fall of gabion boxes h = 0.50m 6 pcs (L = 48m). In order to stabilize the talpe, reduce
the longitudinal slope of the course, reduce the drainage speeds and maintain the
allowances for the foundations of the proposed works, thresholds will be achieved with drops of gabion boxes. The section consists of a spill threshold from a gabion box
0.50×2.00×4.00m, with concrete beam block (0.50×1.00m), 7.00 m long energy
dissipator made of two gabions 0.50×3. 00×4.00. The boxes are trapped downstream
with the 0.80×1.50m concrete beam. Rizberma with a length of 5.00 m consists of
rockfills with g> 440kg / pcs.
Fall of gabion boxes h = 0.30m 1 piece (L = 8m). The section consists of a spill
threshold from a gabion box of 0.30×3.00×4.00m, with concrete beam block
(0.50×1.00m), a 7.00m long energy dissipater made of two gabion boxes
0.30×3.00×4.00, respectively 1.00×3.00×4.00m. The boxes are trapped downstream with
the concrete beam of 0.50×1.00m.
Basic preparatory works are required for the basic works: clearing the trees in the site
and scraping off the works.
The proposed adjustment works preserve the existing valley route, avoiding the
influence on the surrounding area.

MATERIAL AND METHODS
MIKE 11 is a professional engineering software package for simulation of one-
dimensional flows in estuaries, rivers, irrigation systems, channels and other water
bodies. MIKE 11 is a 1-dimensional river model. It was developed by DHI Water • Environment • Health, Denmark.
The Hydrodynamic Module (HD), which is the core component of the model, contains
an implicit finite-difference 6-point A bbott-Ionescu scheme for solving the Saint-
Venant’s equations. The formulation can be applied to branched and looped networks
and flood plains. HD module provides fully dynamic solution to the complete nonlinear 1-D Saint Venant equations, diffusive wave approximation and kinematic wave
approximation, Muskingum method and Muskingum-Cunge method for simplified
channel routing. It can automatically adapt to subcritical flow and supercritical flow. It
has ability to simulate standard hydraulic structures such as weirs, culverts, bridges,
pumps, energy loss and sluice gates.
The MIKE 11 is an implicit finite differe nce model for one dimensional unsteady flow
computation and can be applied to looped networks and quasi-two dimensional flow
simulation on floodplains. The model has been designed to perform detailed modeling
of rivers, including special treatment of floodplains, road overtopping, culverts, gate
openings and weirs. MIKE 11 is capable of using kinematic, diffusive or fully dynamic, vertically integrated mass and momentum equations.
Boundary types include Q-h relation, water le vel, discharge, wind field, dam break, and
resistance factor. The water level boundary must be applied to either the upstream or
downstream boundary condition in the model. The discharge boundary can be applied to
either the upstream or downstream boundary condition, and can also be applied to the
side tributary flow (lateral inflow). The late ral inflow is used to depict runoff. The Q-h
relation boundary can only be applied to the downstream boundary. MIKE 11 is a

18th International Multidisciplinary Sc ientific GeoConference SGEM 2018
 modeling package for the simulation of surface runoff, flow, sediment transport, and
water quality in rivers, channe ls, estuaries, and floodplains.
MIKE 11 has long been known as a software tool with advanced interface facilities.
Since the beginning MIKE11 was operated through an efficient interactive menu system
with systematic layouts and sequencing of menu s. It is within that framework where the
latest ‘Classic’ version of MIKE 11 – vers ion 3.20 was developed. The new generation
of MIKE 11 combines the features and experiences from the MIKE 11 ‘Classic’ period,
with the powerful Windows based user interface including graphical editing facilities and improved computational speed gained by the full utilization of 32-bit technology.
The computational core of MIKE 11 is hydrodynamic simulation engine, and this is
complemented by a wide range of additional modules and extensions covering almost
all conceivable aspects of river modeling.
MIKE 11 has been used in hundreds of application around the world. Its main
application areas are flood analysis and alleviation design, real-time flood forecasting,
dam break analysis, optimization of reser voir and canal gate/s tructure operations,
ecological and water quality a ssessments in rivers and wetlands, sediment transport and
river morphology studies, salinity intrusion in rivers and estuaries MIKE 11 offers a
variety of options for modelling of sedime nt transport dynamics and morphological
changes in the river bed.
Transport models are available for fine, cohesive sediments, such as clay and silt, non-
cohesive sediments, such as sand, gravel and boulders, as well as mixed sediments
[3,6,7].

RESULTS
Numerical modelling was performed with the program MIKE11. Site plan in this
situation is shown in Figure 2.

Figure 2 Plan view with the network model.
Cross sections through the channel as topogr aphical surveys are shown in Figure 3.

Ecology and Environmental Protection
 
 

Figure 3 Cross sections.
According to data entry or formulated bounda ry conditions, namely the upstream inflow
[1,6,7] at chainage 1694 are constant Q 46 mc/s [5] and in the downstream at chainage 1037 curve key for downstream section of the river [2].
After running the program MIKE11 was obtained through existing channel longitudinal
profile, presenting water levels along the channel (Figure 4).

18th International Multidisciplinary Sc ientific GeoConference SGEM 2018
 

Figure 4 Longitudinal profile.
In a morphological model with dynamic feedback between the hydrodynamics,
sediment transport and bed level and planform changes, the upstream sediment transport
boundary condition is important.
The longer the simulation period is, the more important the boundary condition is.
Basically, two types of boundaries can be imposed: Bed levels or sediment transport rates at the boundary.
The former is often applied, if it can be assumed with good approximation, that the bed
level remains the same at the upstream boundary.
The latter is applied, if specification of sedi ment transport (e.g. a zero transport) can be
done accurately.
According to data entry or formulated bound ary conditions, the upstream inflow [2] at
chainage 1694 and in the downstream at chainage 1037 sediment transport is 0 [4].
After running the program MIKE11 ST module was obtained through existing channel
sediment transport in longitudinal profile with min and max., presenting sediment
transport for all time period according with food discharge hydrograph along the
channel (Figure 5).

Ecology and Environmental Protection
 
 

Figure 5. Sediment transport in longitudinal profile.

CONCLUSION
This study presents the application of a 1-dimensional unsteady flow hydraulic model
used for the simulation of flow in rivers: the MIKE 11 model from the Danish
Hydraulic Institute (DHI).
Advantages of MIKE 11 (1D model) are: possi bility of accurate hydraulic description in
rivers/channels which are one-dimensional flow with many complex hydrotechnical
structures; short simulation time; easy to view analyses and extract results.
The MIKE 11 non-cohesive sediment trans port module (NST) permits the computation
of non-cohesive sediment transport capacity, morphological changes and alluvial resistance changes of a river system. Inpu t data concerning non-cohesive sediment
properties are defined in the ST Parameter Editor which contains the following tabs
(property pages):
– Sediment grain diameter
– Transport model
– Calibration factors
– Data for graded ST – Preset distribution of sediment in nodes
– Passive branches
– Non-Scouring Bed Level

18th International Multidisciplinary Sc ientific GeoConference SGEM 2018
 With its exceptional flexibility, speed and user friendly environment, MIKE 11 provides
a complete and effective design environment for engineering, water resources, water
quality management and planning applications. The Hydrodynamic (HD) module is the nucleus of the MIKE 11 modelling system and forms the basis for most modules
including Flood Forecasting, Advection-Disp ersion, Water Quality and Non-cohesive
sediment transport modules.

ACKNOWLEDGEMENT

This paper can be possible thanks to proj ect: Development of knowledge centers for
life-long learning by involving of specialists and decision makers in flood risk
management using advanced hydroinformatic tools, AGREEMENT NO LLP-LdV-ToI-
2011-RO-002/2011-1-RO1-LEO05-5329. This pr oject has been funded with support
from the European Commission. This publication [communication] reflects the views
only of the author, and the Commission cannot be held responsible for any use which
may be made of the information contained therein.

REFERENCES
[1] Henderson, F.M. (1966). Open Channel Flow. MacMillan Company, New York,
USA.
[2] David, I. Hydraulic I and II, Polytechnic Institute Traian Vuia Timisoara, Romania,
1984
[3] *** (2011), MIKE 11 – A modeling system for rivers and channels, Short
introduction and tutorial, DHI, Horsholm, Denmark.
[4] *** Archive ANIF, 2015, Data from various documents and studies.
[5] National Administration “Romanian Waters” (NARW), Banat, 1987-2015. Data
from various documents and studies.
[6] Z. Marossy, R. Beilicci, E. Beilicci, M. Visescu, Advance Hydraulic Modeling of
Irrigation Channel CP3, in Irrigation System Teba – Timisat, Romania, Timis County,
International Multidisciplinary Scientific GeoConference-SGEM, Bulgaria, vol I, pp 39-
46, 2016
[7] M. Visescu, E. Beilicci, R. Beilicci, Se diment Transport Modelling with Advanced
Hydroinformatic Tool Case study – Modelling On Bega Channel Sector, World
Multidisciplinary Civil Engineering-Architecture-Urban Planning Symposium
(WMCAUS), Czech Republic, vol. 161, pp. 1715-1721, 2016.