Download Team 5 - HydroEurope

WEIR MANAGEMENT AS
STRUCTURAL MEASURES
FOR FLOOD REDUCTION
Contents
I.
Introduction
What is weir? Weir formulas?
II.
Approaches
Research Based Approach
Modelling Based Approach
III. Conclusion
Introduction
Weir Small overflow-type
dam generally used to
increase the level of a
river or stream.
Weir Formula (for Mike 11)
I. Villemonte (Villemonte, 1947) formula for sharp crested weirs
Weir Formula
II. Honma formula (we use this)
III. Extended Honma formula
Weir Formulas (for ISIS)
Dry Mode
Q=0
Free Flow (we use this for ISIS)
Drowned Flow
Round Nosed Broad Crested Weir (free flow)
Research Based Approach
1st Solution – Cut Off the Crest
High Overflow
Research Based Approach
2nd Solution – Adding Geotextile
High Overflow
Research Based Approach
3rd Solution – Automated Gate
Modelling approach
Define objectives

1.
2.



Reduce downstream flooding
Find optimal heights for sediment equilibrium
Calibrate MIKE11 against observed levels
Build same model in ISIS
Compare results using ‘multi-model
approach’
Multi-model approach

Model is the sum of the experience of the
person who wrote the code
Reduce downstream flooding
No changes

140
120
100
ISIS
measured
80
Bed Level
MIKE11
60
40
20
0
0
5000
10000
15000
20000
25000
30000
Reduce downstream flooding

Downstream weir removed
140
120
100
ISIS
measured
Bed Level
80
MIKE11
60
40
20
0
0
5000
10000
15000
20000
25000
30000
Reduce downstream flooding

Four downstream weirs removed (1, 4, 5, 6)
140
120
100
ISIS
measured
80
Bed Level
MIKE11
60
40
20
0
0
5000
10000
15000
20000
25000
30000
Reduce downstream flooding

Weirs removed and manning’s reduced
140
120
100
ISIS
measured
80
Bed Level
60
MIKE11
40
20
0
0
5000
10000
15000
20000
25000
30000
Sediment transport
Meyer-Peter formula
qs
related to q, s0, d50
steady-state model
• Mean flow depth
• Mean channel width
• Mean velocity
• Channel Slope
• Particle diameter d50
http://ponce.sdsu.edu/onlinemeyerpeter.php
Sediment transport

Results
qs (kg/sec/m)
Qs (kg/sec)
Weir No.
1.6
340
16
0.54
144
10
0
0
9
0
0
8
0.56
47
7
0.3
32.4
6
0
0
5
2.7
274
4
0.012
2.6
1
Conclusions
MIKE11 results more sensitive to weir
removal
Cannot conclude on effectiveness of weir
removal due to model disagreement
Reduction of channel roughness better
Proposals:




1.
2.
Vegetation clearance downstream
Alteration of weirs to improve sediment regime
Sean and Ahmed who
persistently work on
Mike 11 and ISIS
Kim - our hydrological
analysis expert
Alex – Partially involved
to Mike 11 and
Hydrological Analysis.
Our report maker.
Stephane – our GIS
expert
Fazlul is working on
Mike 11 and ISIS
Prima and Rajmund are
working on Mike SHE
report
Amandine – our
hydrological analysist
& web designer
Acknowledgment
Prof. Dr.-Ing. habil Klaus-Peter
Holz as team 5 supervisor and
his patience for assisting us
during Hydroeurope 2010
References



Wikipedia (2010). Weir. Wikipedia
Foundation, Inc.
http://en.wikipedia.org/wiki/Weir
White, Frank (2006). Fluid Mechanics.
Mcgraw-Hill Education
Villemonte, James R. 1947. Submerged-Weir
Discharge Studies, Engineering News. 1943.
Engineering News Record, pp. 118-120.
Record, pp. 54-57