Govert D. Geldof
Geldof c.s., Tzum, The Netherlands
19th International River Symposium
New Delhi, 12 - 14 September 2016
Mathematics,
World of Ideas
statistics, …
Real Knowledge
Plato 427 - 347 BC
Opinions
Ignorance
Plato 427 - 347 BC
The weather
outside is
wrong
I think it is
raining
I am getting
wet
Real Knowledge
Opinions
Ignorance
Explicit
knowledge
This presentation
Implicit
knowledge
(tacit)
Dikes (levees)
 2,600 km primary dikes
 14,000 km regional dikes
 Locks, pumping stations,
harbours, …
 Historical value (water
boards from 11th Century)
 Law based standards
 National High Water
Protection Programme
(HWBP)
Piping
 Problem in areas with
sandy soils
 Model: the Sellmeijer
formula (assessment)
 Probabilistic approach
 Embedded in “the world
of ideas”
Zwarte Water
• Ten kilometres primary dike close to Zwolle;
• One of the oldest polder areas with historical value
and many dike houses;
• First assessment (model based): piping is a huge
problem;
• As a consequence: we have to add it to the High
Water Protection Programme;
• Estimated costs: € 1 million per kilometre
Practitioners did not agree to conclusions …
Tendency modern approach
Man
Model
Measurement
“where order meets chaos”
People with different models, data, opinions
and ignorance
Three propositions
1. The complexity of water
projects increases
2. For coping with complexity
tacit knowledge is crucial
3. Tacit knowledge decreases
YES
YES
YES
+
Problem
Five Spheres
The Governance
& Politics Sphere
“Push the costs to
central government”
“We do not have
enough people”
Management &
Control Sphere
“We need more data,
to calibrate the
model”
The Connecting
Sphere
“They do not
understand us”
“We have to interact
with stakeholders”
The Shadow
The Rationalising
Sphere
The Rooted
Sphere
“This dike is OK”
Tacit Knowledge
The Governance
& Politics Sphere
 You will find tacit
knowledge in all five
Spheres
 The Spheres are drifting
apart… people are not
talking each others’
language
 As a result, tacit
knowledge is getting
isolated in the Spheres
(there is no flow
anymore)
Management &
Control Sphere
The Connecting
Sphere
The Shadow
The Rationalising
Sphere
The Rooted
Sphere
Conceptual models
are not effective when
there is no flow of
tacit knowledge
Workstead
 Focussing on a small, local





and concrete issue
(complex);
8 – 10 people, all Spheres
included;
At the project’s location;
Narrative approach:
bringing tacit knowledge
into play;
Not avoiding “moments of
despair”
Base for Guilds 2.0
(apprentice, journeyman
and master).
B&B Tea Garden
Workstead “Zwarte Water”
Entrance at ditch
pipe
Based on this model: the dike has a serious piping problem
The model reduces the problem’s complexity
Workstead “Zwarte Water”
Entrance at ditch
Entrance at river
Wind effect
Infiltration resistance
pipe
Due to tacit knowledge flow the problem is reduced significantly
Result
 Assessment, design and
maintenance are handled in
relation to each other;
 There are only minor problems:
we can save 95% of € 10 million;
 A learning effect for all people
involved (also board member,
manager): there has been a real
tacit knowledge flow;
 A new man, model and
measurement balance has
emerged.
To summarise:
Adapt…
Let’s make an integral
model, so we can
optimise the system
Complex
Issue
issue
The more complex an issue is, the closer
you have to act to practice
Thanks for your attention