Transcript Royal Haskoning PPT template

Building with Nature in practice:
Two examples on wetland restoration
Petra Dankers & Thomas Vijverberg
19 April 2011
Introduction
Wetland = areas of marsh, fen, peatland or water, natural
or artificial, permanent or temporary, water that is
static or flowing, fresh, brackish or salt.
Two examples of Building with Nature in practice

Creating new wetland
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Lake Marken marsh project
Wetland restoration
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Managed realignments
Perkpolder project
Creating new wetland – focus on lakes
Why?
degeneration of lake systems
creating stepping stone
creating habitat
nature compensation
Example: Case Markermeer
Lake Marken
- high turbidity
- no interesting ecosystem
While the lake would be suitable as
- stepping stone
- habitat for fresh water flora and fauna
- high quality recreation and living area
Example: case Lake Marken
NMIJ project – More natural Lake Marken and
Lake IJ
goal: developing measures to create a robust
ecosystem and climate proof water system
measure: enlarging habitat diversity by
creating a large fresh water marsh (wetland)
Task: give advice on building/creating new
wetland
BwN: allow natural processes to shape and
develop the wetland (no polder, no dikes
preventing water inflow, open boundaries)
Creating new wetland
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What is a large fresh water marsh?
Step 1: reference situations
Step 2: translate to Lake Marken situation
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How do you make it?
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Step 1: decide on species, size and material
Step 2: start building
What is a large fresh water marsh?
What is a large fresh water marsh?
What is a large fresh water marsh?
-
Shallow water, creeks, (10%)
Mud and sand flats (10 – 20 %)
Water and gently sloping shores with abundant water plants
(10 – 20%)
Sedges (biezen) and phragmytes (riet) in shallow water (up to
50%)
floodplains (5%)
Dynamic with pionier vegetation
Erosion and sedimentation
What is a large fresh water swamp?
How do you make it?
Which species?
Which size?
Which material?
Which species and size?

400 a 500 ha to have 75% of marsh birds
Building block plas dras
Which material
Material from Lake Marken
- top layer is holocene material (mud, clay, peat)
< 10-15 m is sand (building sand)
But how do you build with mud?
is it stable, does it stay in place?
does it set and how much?
how much does it consolidate?
when can things start growing?
when can you walk on it?
 PILOT LAKE MARKEN MARSH
Pilot Marsh
Ecology is leading but
engineering is tested
(because of time frame)
Laboratory in Lake Marken of a
few ha.
Testing consolidation,
construction, behaviour and
suitability for developing
marsh/swamp pioneer
vegetation
Result: in 2015 advice
on creating large
marsh in Lake Marken