This case study examined the use of Building with Nature (BwN) principles in coastal nourishment projects. Traditionally, small amounts of sand are periodically placed on shorelines when erosion threatens a reference line. However, this risks disturbing marine ecosystems every five years. The case study looked at depositing a large, 21.5 million m3 sand volume called a "sand engine" along an 18 km coastline near Delfland, Netherlands. The goal was for waves, currents and wind to naturally distribute the sand over decades, reducing erosion and ecosystem disruption compared to traditional small, frequent nourishments. Guidelines, tools and previous examples were needed to mainstream this BwN approach.

1. 1

2. SUSTAINABLE HYDRAULIC
ENGINEERING THROUGH
BUILDING WITH NATURE
PRESENTED BY: CHINJU SAJU
2012-02-017
GUIDED BY: Dr.ASHA JOSEPH
2
Seminar on:

3. CONTENTS
1. Introduction
2. What is sustainability?
3. Hydraulic engineering
4. Building with nature
5. Principles of BwN
6. Design steps for BwN
7. Spectrum of applicability
8. BwN solution for flat slope
3

4. Contd…
9. BwN solution for moderate slope
10. BwN solution for steep slope
11. BwN in riverine environment
12. BwN in sandy shores
13. BwN in lake shores
14. BwN in estuarine environment
15. BwN approach in dredging
16 .Advantages of BwN
17. Disadvantages of BwN
18. Case study
19. Conclusion
20. References
4

5. • Present day trends in society and in the
environment put ever higher demands on
engineering infrastructures.
• Mono-functional solutions designed without
due consideration of the surrounding are no
longer accepted.
• Sustainability, multi-functionality and
stakeholder involvement are required instead.
5

6. Contd…
• It would be better if we adopt pro-active
approach, minimizing and mitigating the impacts
of a set design, rather than a reactive approach.
• Hydraulic engineering infrastructures are of
concern to many people and are likely to interfere
with the environment.
• In times of rapid societal and environmental
change this implies that sustainability and
adaptability are considered most.
6

7. Contd…
• So it is essential to need a system starting from the
natural system and making use of nature’s
ecosystem services meeting society’s needs for
infrastructural functionality, and to create nature
development.
• Here is the need for sustainable hydraulic
engineering.
7

8. WHAT IS SUSTAINABILITY??
8

9. • In ecology, sustainability is the capacity to endure.
• It is how biological systems remain diverse and
productive indefinitely.
• In more general terms, sustainability is the
endurance of systems and processes.
• The organizing principle for sustainability
is sustainable development, which includes the four
interconnected domains: ecology, economics,
politics and culture.
9

10. HYDRAULIC ENGINEERING
• Hydraulic engineering as a sub-discipline of civil
engineering is concerned with the flow and
conveyance of fluids, principally water and sewage.
• One feature of these systems is the extensive use
of gravity as the motive force to cause the
movement of the fluids.
• Intimately related to the design of
bridges, dams, channels, canals, and levees, and to
both sanitary and environmental engineering.
10

11. Contd…
• Hydraulic engineering is the application of fluid
mechanics principles to problems dealing with
the collection, storage, control, transport,
regulation, measurement, and use of water.
• The hydraulic engineer is concerned with the
transport of sediment by the river, the interaction
of the water with its alluvial boundary, and the
occurrence of scour and deposition.
• This can be improved sustainably by adopting
building with nature.
11

12. • Building with Nature (BwN) is about meeting
society's infrastructural demands by starting from
the functioning of the natural and societal systems in
which this infrastructure is to be realized.
• It requires a different way of thinking, acting and
interacting.
12

13. Thinking
Acting
Interacting
13

14. THINKING
• Thinking start from a
certain design concept
focusing on the
primary function, the
natural system, its
dynamics, functions
and services, and from
the vested interests of
stakeholders
ACTING
• Post delivery
monitoring and
projections into the
future are an integral
part of the project.
This also creates
opportunities to learn
a lot more from these
projects than from
traditional ones.
INTERACTING
• This requires a
different attitude of
all parties involved
and different ways of
interaction, in
interdisciplinary
collaborative settings
14

15. DESIGN STEPS FOR BwN
1.Understand
the system
2.Identify
realistic
alternatives
3.Preselect an
integral
solution
4.Fine-tune an
integral
solution
5.Prepare the
solution for
implementation
15

16. SPECTRUM OF APPLICABILITY
•BwN solution may be applied in different
situation, be it coastal or riverine, sandy or
muddy or dominated by living components, is
governed by the ambient physical system.
• Four parameters considered during BwN
applications are:
a. Bed slope
b.Hydrodynamic energy
c.Salinity and
d. Geo- climatic region .
16

17. Where we can apply BwN?
It can be applied in different contexts such as
1. Flat slope
2. Moderate slope
3.Steep slope
4.Riverine environment
5.Sandy shore environment
6.Lake shore environment
7.Estuarine environment
8.During dredging
17

18. BwN SOLUTION FOR FLAT SLOPE
•In low-slope environments generic BwN solutions
can be completely sediment-based.
•High-energy tidal environments favour designs that
are wide and contain a large volume of sediment
• The low-energy sheltered environments allow soft
solutions with high biomass, lower width.
•This often results in a mix of sand and mud,
stabilized by vegetation cover.
18

19. BwN SOLUTION FOR MODERATE
SLOPE
•As the bed slope increases, the width available
for a soft foreshore in the wave impact zone is
reduced .
•To maintain safety against flooding, hybrid
solutions -‘stable sediment foreshore with hard
dike’ combination is required.
•The foreshores in these solutions can typically be
stabilized through vegetation and/or reef-
structures
19

20. BwN SOLUTION FOR STEEP SLOPE
•As the bed slope increases further, hard
solutions may eventually prevail as most
suitable solution.
•It is possible, however, to introduce
ecological enhancements on hard solutions,
in order to increase habitat diversity,
biodiversity or productivity of the structures
20

21. Fig. 1. Range of potential BwN applications along the
main axes of given bed slope and hydrodynamic
energy
21

22. BwN IN RIVERINE
ENVIRONMENT
22

23. •Main objective is to protect the rivers against floods
and natural rehabilitation.
•Done by reconnecting removed floodplain area to the
river, thus restoring the storage capacity
• Part of the returned floodplain area was made
available to nature development.
•The strategy is to solve the dilemma between flood
protection and nature rehabilitation .
23

24. General applicability of BwN in rivers
• Flood alleviation and nature restoration are not the
only river issues.
• Dam building, excessive water off take, sand mining
and normalisation are activities that profoundly
influence river behaviour and invoke a variety of
problems.
• Erosion and groundwater level drawdown are other
cases.
24

25. Contd…
• Water management has to be attended with
corresponding sediment management along with flood plain
management are done for solving the issues.
•Done in terms of flow discharge, sediment transport and
morphological behaviour.
• The river bed builds up far above the surrounding area,
leading to an increased flood risk.
•Solution is to flush the river from time to time by creating
so-called man-made floods.
•Through joint operation of three consecutive reservoirs,
they create a flood wave and at the same time release large
amounts of sediment from the reservoirs
25

26. Fig. 2. Man-made flood generation in the Yellow River at Xiaolangdi, China. The highly
sediment-laden flow scours the river channel over a long distance downstream
26

27. BwN IN SEA SHORES
27

28. •Sea nourishment is the principle which is a nature-
friendly and sustainable way of coastal maintenance,
even in times of sea level rise.
•Present day practice is reactive: whenever the coastline
threatens to withdraw behind a given reference line, a
relatively small amount of sand is placed on the beach or
the upper shore face.
•Drawback is every nourishment buries part of the
marine ecosystem.
28

29. Contd…
•Nourishing only the upper part of the shore face tends
to lead to over-steepening of the coastal profile.
•In the long run, frequent nourishment is required.
•This over-steepening leads to an increased
susceptibility to coastal erosion.
29

30. Contd…
•Nourishing a large amount at once is a better
solution.
•The idea is that in the coming decades the sand will
be distributed by waves, currents and wind feeding
the lower shore face, as well as the subaqueous and
sub-aerial beach and the dune area.
30

31. Contd…
Fig. 8. Upper panel: The Delfland Sand Engine shortly after placement (July 2011).
Lower panel: The Sand Engine has evolved into an almost symmetrical salient (October
2013).
31

32. BwN IN LAKE SHORE
ENVIRONMENTS
32

33. • Lakes in soft sediment environments like deltas tend
to expand in the direction of the prevailing winds.
• As this process continues, they become more
susceptible to wind-induced water level variations,
especially at the eroding end.
• Also, floods in adjacent rivers may cause flood
problems.
33

34. Contd…
• Conventional solution for this is dike building .
•The height of a traditional dike is determined by
a. Wave overtopping restrictions,
b. Geo-mechanical stability requirements
c. Seepage length to prevent piping
• As an alternative to dike raising, one may consider
designs that reduce the wave attack and increase the
stability and the seepage length.
34

35. Contd…
• Depending on the local situation, a shallow vegetated
foreshore may be such an alternative.
•Both the shallowness of the foreshore and the
vegetation on top of it attenuate incoming waves
before they reach the dike.
•It carry valuable ecosystems along with water
purification, living environment for a variety of species,
carbon sequestration and biomass production.
35

36. Fig. 13. Artist impression of a hallow foreshore in front of a traditional
dike; the dark brown material is clayey, in order to prevent seepage;
the light brown material is sandy, as a buffer against erosion .
36

37. BwN IN ESTUARINE
ENIRONMENT
37

38. • Bio-architects or ecosystem engineers are species
that modify their habitat, to their own benefit
and that of other species.
• The activities of bio-architects may have other
positive effects, such as sediment trapping and
coastal protection.
• Oysters and coral are examples, they build reefs
that provide habitat to a wide range of other
species.
38

39. Contd…
• To interrupt the sediment transport from the shoals
into the gullies can be done by creating oyster reefs
on the shoal edges.
• Since oyster shells are the perfect substrate to settle
on for juvenile oysters, gabions filled with oyster
shells were placed on the shoal edges at various
locations.
39

40. Fig. 15. Placement of gabions with oyster shells
40

41. Fig. 16. Successful oyster reef after one year .
41

42. BwN APPROACH IN
DREDGING
42

43. What is Dredging???
•Dredging is an excavation activity or operation usually
carried out at least partly underwater, in shallow seas
or fresh water areas.
•The purpose is gathering up bottom sediments and
disposing of them at a different location.
•This technique is often used to keep waterways
navigable.
43

44. BwN APPROACH
• Dredging leads to environmental concerns.
• It will create a turbulence in sea water which
adversely affect the aquatic life.
• BwN proposes to reverse the order, starting from
the ecosystem's vulnerability and working one's
way back to the dredger.
44

45. Contd…
• Optimization can be done by knowing the
environmental conditions.
• The maximum allowable sediment release at every
location and every point in time of a given ecosystem
and the hydro- dynamic and sediment conditions
in its surroundings could be work out using a
sediment dispersion model.
45

46. •Figure shows a screen
shot of a dredging support
tool in which this has been
implemented.
• The green dots indicate
locations where exposure
to turbidity is predicted to
remain below predefined
threshold levels.
•The tools supports
planning the dredging
operation such that this is
secured
46

47. ADVANTAGES OF BwN
47

48. • BwN instead of Building in Nature is an innovative
approach in ecosystem development. But
a different way of thinking, acting and interacting is
required.
• This program is to the integration of infrastructure,
nature and society in new forms of engineering
that meet and sustainable solutions.
• It involves disciplines from natural sciences,
technology and social sciences to successfully
operate in between nature, engineering and
society.
48

49. Contd…
• Via case studies and projects, it connects with
current problems in nature by interacting with
biotic and abiotic factors.
• This approach involves detailed analyses of
physical, ecological and social systems.
• The results of the cases, pilot projects and
scientific research are done by people actively
involved in hydraulic engineering and water and
ecosystem management.
49

50. DISADVANTAGES
OF BwN
50

51. • It requires a complete reworking of the material
into guide- lines for practical use, user-friendly
tools, tutorials, low- threshold access to data and
models, examples of earlier projects, ready-to-use
building blocks, etc.
• Mainstreaming the approach in practical hydraulic
engineering projects still meets several obstacles
such as conservatism, risk aversion, high cost.
51

52. CASE STUDY
52

53. CASE STUDY
• Eco system engineering and biodiversity in
coastal sediments: posing hypothesis
Done by:Tjeerd J. Bouma,Sergej Olenin,
Karsten Reise and Tom Ysebaert
Done at :Coastal research & Planning
Institute, Klaipeda University,
Klaipeda, Lithuania.
53

54. OBJECTIVES
• Studying BwN approach by nourishing the
upper shore-face using sand engine at a larger
extend whenever the coastline threatens to
withdraw behind a given reference line.
54

55. Conventional practice is….
• Whenever the coastline threatens to
withdraw behind a given reference line, a
relatively small amount of sand (up to a few
million m3) is placed on the beach or the
upper shore-face.
• Typical return period of this practice is five
years.
55

56. Disadvantages of traditional practices
are:
• Every nourishment buries part of the marine
ecosystem.
• Five-yearly nourishments tend to bring the
ecosystem into a permanent state of disturbance.
• Nourishing only the upper part of the shore face
tends to lead to over-steepening of the coastal
profile leads to soil erosion and, the necessity to
nourish ever more frequently.
56

57. Solution for this is…
• In 2011, the Province of Zuid-Holland and
Rijkswaterstaat started an experiment to find out
whether nourishing a large amount at once is a
better solution.
• Between February and July 2011, 21.5 million m3 of
sand was deposited on the shore face in front of the
Delfland coast, between The Hague and Rotterdam.
57

58. MATERIALS AND METHODS
• Complete reworking of the material into guidelines
for eco-friendly practical use, user friendly tools, low
threshold access to data & models, examples of
earlier projects, ready to use building blocks, etc. are
reqd.
• The idea of this mega nourishment using sand
engine is that the sand will be distributed by waves,
currents and wind over this 18 km long coastal reach,
thus feeding the lower shore face, as well as the
subaqueous and sub aerial beach and the dune area.
58

59. Advantages of this system are…
• Once the nourishment has been placed, the
ecosystem is expected to suffer less than in the
case of repeated small nourishments.
• Less harm done to or even new opportunities for
the ecosystem such as recreational opportunities
a wider dune area and a better adaptation of the
coastal defense system to sea level rise
59

60. RESULTS AND DISCUSSIONS
• Survey showed that in the two years since
construction about 2 million m3 of sand (i.e. some
10% of the total volume) have moved, of which 0.6
million m3 have stayed on the Sand Engine, 0.9
million m3 in its immediate vicinity and 0.5 million
m3 have been transported outside the survey area,
which agrees well with earlier model predictions
60

61. Contd…
• Yellow River Delta, where the sediment source
was first fixed in place by embanking the river,
and subsequently reduced by a dam-induced
change of the discharge regime , followed by a
coarsening of the bed, both of which bring
down the river sediment transport capacity.
61

62. Fig. 9. Evolution of the annual runoff and sediment discharge Lijin Hy-
drological Station, Lower Yellow River, China. The dashed lines represent the
linear trend through the available data points 62

63. Fig. 10. Coastal degradation between 2003 and 2013
near Demark, Indonesia .
Fig. 10 shows an example of the north coast of Java
near Demark, Indonesia, where heavy erosion started
after the fish ponds, which covered the entire coastal
zone, had been abandoned. Given the many ecosystem
services provided by mangrove forests, their restoration
seems attractive here.
63

64. Case study concludes as…
• The idea of mega nourishments is better than small
nourishments of sand in dune areas since the
ecosystem is expected to suffer less.
• In mega nourishment during two years of
construction, 30% stayed on the sand engine, 45%
moved to immediate vicinity, 25% have been
transported to outside area.
64

65. Contd…
• Ecologically speaking, the Sand Engine exhibits
interesting developments e.g., juvenile dune
formation and establishment of pilot vegetation,
including rare species.
• It also turns out to be a favourite resting area for
birds and seals, and the lagoon is full of juvenile fish.
• Initial investment is high, but in effectively less
regarding the overall sum.
65

66. Contd…
• The concept and the way of thinking underlying the
Sand Engine are generic for eroding sandy coasts, but
its design cannot simply be copied to other locations.
• The design should rather comply with the local
situation and the local dynamics.
• For the replanted system to survive it is crucial to
have the right combination of coastal morphology,
wave conditions, tidal motion, fresh groundwater
availability, sediment supply and plant species
66

67. CONCLUSION
• Sustainable hydraulic engineering BwN approach is
the need of the hour.
• The existing experiments, pilot projects and
showcases show that the BwN approach works,
provided that one thinks, acts and interacts
accordingly.
• Knows the natural biotic and abiotic environment in
which an infrastructural functionality is to be
realized.
67

68. Contd…
• Initiatives in different countries and international
organizations are merging into an international
movement, but still meets a number of obstacles.
• They need to be overcome in the next few years in
order to have this approach broadly implemented.
68

69. Contd…
• But from a longer-term and multi-functional
perspective, BwN may just as well be economically
attractive.
• BwN requires investing time and money into
knowing how the natural system including the
ecosystem- functions, an investment that pays off
later, but possibly not as directly as a traditional hard
engineering solution.
69

70. REFERENCES
Baptist, M.J., Penning, W.E., Duel, H., Smits, A.J.M., Geerling, G.W.,
Van der Lee, G.E.M., and Van Alphen, J.S.L. 2004. Assessment
the effects of cyclic floodplain rejuvenation on flood levels
and biodiversity along the Rhine river. River Res. Appl. 20 (3):
285-297.
Bouma, T.J., Olenin, S., Reise, and K., Ysebaert, T.2009. Ecosystem
engineering and biodiversity in coastal sediments: posing
hypotheses. Helgol. Mar. Res. 63 (1): 95-106.
De Vriend, H.J., Van Koningsveld, M. 2012. Building with Nature:
Thinking, Acting and Interacting Differently. In: EcoShape,
Building with Nature. Dordrecht, the Netherlands
70

71. Contd…
Bridges, T.S., Ells, S., Hayes, D., Mount, D., Nadeau, S.C., Palermo,
M.R., Patmont, C. and Schroeder, P. 2008. The Four Rs of
Environmental Dredging Resuspension, Release, Residual
and Risk. Technical Report. US Army Corps of Engineers.
Temmerman, S., Meire, P., Bouma, T., Herman, P., Ysebaert, T., and
De Vriend, H.J., 2013. Ecosystem-based coastal defense in
the face of global change. Nature. 504: 79-83.
71

72. Thank
you
72