Download Lecture 9

BIO410- Ecology and Environmental Engineering
FALL 2016
By Jasmin Šutković
5th Dec. 2016
Lecture 9: Soil Bioengineering
Outline
Book 2: Chapter 3 – follow the subtitles in this presentations
while reading the book. Page 96-116
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What is Soil Bioengineering
Erosion in nature?
Erosion control
Water erosion
Riprap
What is soil bioengineering?
• Soil bioengineering (SB) uses live plant materials to
provide erosion control, slope and stream bank
stabilization, landscape restoration, and wildlife
habitat.
• Soil bioengineering employs a partnership of the
professions of soil science, landscape architecture,
civil, hydrological, and geotechnical engineering,
and horticulture.
Additional links
• http://www.wsdot.wa.gov/Design/Roadside/SoilBio
engineering.htm
• http://www.thebeautifulgardens.it/eng/soilbioengineering.html
Main concept
• Soil bioengineering primarily involves plant-based
systems but also includes other natural materials
such as stone, wood, and plant fibers.
• The materials, both living and nonliving, must be
able to resist and absorb the impact of energies that
cause erosion.
Why Soil Bioengineering ?
1) they can be less expensive than conventional
alternatives and
2) they have many by-product values
• Although soil bioengineering systems are
multipurpose, in this chapter the focus is on erosion
control.
WHAT IS EROSION ?
• Erosion is a natural process that shapes and
reshapes the landscapes around us. No matter what
you do, erosion will happen. It's natural.
Why create for exp.
Artificial stream?
• Create a stream, that looks, behaves and functions
like natural channel stream!
• Put all features of water stream together in that way
that it becomes self sustainable.
• A properly functioning stream and riparian system supplies
clean water, supports a variety of aquatic and terrestrial life
forms and provides an efficient, stable method of controlling
flows and transporting water and sediment.
• Natural streams exhibit a dynamic equilibrium. While
continually changing, the forces of hydrology, geology and
topography create a natural stream alignment and gradient
EROSSION CONTROL
• Conventional approaches to erosion control involve
the design and construction of fixed engineering
structures.
• These include bulkheads, seawalls, breakwaters,
and revetments which are made of concrete, stone,
steel, timber, or gabions (stone-filled wire baskets).
Revetments
Seawalls
Breakwaters
• The most common and effective type of structure
for bank protection along shorelines or in stream
channels is a carefully placed layer of stones or
boulders known as riprap
• The rock provides an armor which absorbs the
erosive energies and thereby reduces soil loss.
• Rock fragments which make up a riprap revetment
must meet certain requirements of size, shape, and
specific gravity.
Combination with living plants
• Various kinds of vegetation are employed to control
erosion, depending on the environment.
• Woody plants such as willows (Saliaceae) are used
in stream environments and mangroves on tropical
coastlines; herbaceous wetland plants such as
cattails (Typha sp.) are used in freshwater an
cordgrass (Spartina sp.) in saltwater environments.
• Direct mechanisms of erosion control by living
plants include:
1. Intercepting raindrops and absorption of rainfall
energy
2. Reducing water flow velocity through increased
roughness
3. Mechanical reinforcement of the soil with roots.
• A “Bio-Structural” approach to erosion and slope
stability problems; i.e., incorporating planned
vegetational elements in engineering designs, can
be less expensive, more effective, and more
adaptable than purely structural solutions.
Vegetation should be used in conjunction with geotextiles and engineered structures whenever
appropriate and practical.
Soil erosion techniques
• https://www.pinterest.com/yangyilun2002/soilerosion-techniques/
Religions and
• All of the aspects of soil bioengineering design
described above: qualitative, intuitive, “organic,”
and, to a degree, reduced human control, suggest
possible connections with Eastern religions, which
share these qualities.
• Religions are philosophies that help humans decide
how to act and how to think.
Buddhism and Hinduism
• The Eastern religions of Hinduism and various forms
of Buddhism are a related of beliefs based on the
search for enlightenment.
• Correlation between man and the nature through
meditation
• Pirsig (1974) in a Book called : Zen and the Art of
Motorcycle Maintenance introduces Zen Buddhism
indirectly through a story about a cross-country
motorcycle trip. Connection Ecology and religion!!!
• The ways of NATURE exist, man must only adapt and
understand In order to get benefits from it.
• One particular example of possible application of
Eastern religion to ecological engineering is the
dualist notion of life situations represented by the
polar opposites yin and yang.
• This diagram is a symmetric arrangement of the dark yin and
the bright yang, but the symmetry is not static. It is a
rotational symmetry suggesting, very forcefully, a continuous
cyclic movement …
• The two dots in the diagram symbolize the idea that each
time one of the two forces reaches its extreme, it contains in
itself already the seed of its opposite.
Ecology and Ying –Yang relations
• Ecology, too, can be characterized by the interplay between
polar opposites such as primary production and respiration
from ecosystem energetics or in the growth (r) and
regulation (K) terms in the classic logistic equation from
population biology:
• In conclusion, the point of this section is to suggest
relationships between Eastern religions and design
in soil bioengineering and, to some extent, more
broadly in ecological engineering.
• Successful soil bioengineering often depends on
the ability of the designer to “read” a landscape and
arrive at a design through observation, intuition,
and experience.
Example of Zen water gardens