EcoEng Newsletter No. 11, October 2005

Building bridges between ecology and civil engineering

Content No. 11/05
Title page / Index
From the editors
Faces: H.v.Bohemen
Review: EE Book
Overview, Etnier
Kirk et al.
Composting (ch. 4)
Fecal composting
Policy Finl, Mattila
Desert infrastruct.
Writers' Fund
Ecosan Durban 05
Good bye T. Rohrer
Various issues:
Joe's Corner
Mailing list

Email-Interview with Dr. Hein van Bohemen, IEES board member

Lecturer Ecological Engineering,
University of Technology Delft (TUD),
Citg-section CM/DB,
POB 5048,
2600 GA Delft

By Andreas Schoenborn-Schaller, EcoEng-Newsletter

Dr. ing. Hein van Bohemen has been head of the Environmental Research Department of the Road and Hydraulic Engineering Institute of the Ministry of Transport, Public Works and Water Management in the Netherlands and is now working as lecturer on Ecological Engineering at the University of Technology in Delft, The Netherlands. He has special interest and received his education in horticulture, ecology, landscape ecology and ecological engineering in relation to civil engineering. Hein van Bohemen is one of the founding members of IEES (founded 1993).

New book: Ecological Engineering - Bridging between ecology and civil engineering, Edited by Dr. ing. Hein van Bohemen, Aeneas Technical Publishers, Delft, 2005
Review of this book

Andreas Schoenborn:

Hein, when I read through your book - one of the few existing textbooks on Ecological Engineering, by the way - I got stuck on the first page already where you wrote:

' In view of the changes that are currently occurring [...] the formulation of a (landscape) ecological and Ecological Engineering vision can contribute [...] to incorporate the interests of nature and the environment' .

What are these interests in your view? And how can we know them?

Hein van Bohemen:

In my view, the interests of nature and the environment are the interests of plants and animals, as well as the interests of humans, as we are biological entities. Since plants and animals have no real voice and no participation in human decision-making processes, we should give extra care towards their needs. Ecology and Ecological Engineering can contribute to the use of nature by humans as well as help safeguarding natural values.

This can be done in an integrated ecosystem approach. We need to keep in mind that the natural values are not really existent [outside of our perception] but are given by humans. Furthermore, I would like to mention that the main aim of my book is to provide some basic knowledge as well as many examples in order to stimulate a more integrated approach.

Fig. 1: A fauna passage in Banff national park, Canada: A mitigation measure designed to minimize the negative impact of the road on nature. (Photo: H. van Bohemen)


So, Ecological Engineering is basically a gentle ethical approach to do engineering and can be applied to any kind of engineering, am I right? Or do you see any limitations, such as fields where Ecological Engineering is not applicable?


In the field of civil engineering, Ecological Engineering can be applied in many cases. In wastewater treatment its application has become part of the everyday experience. But even in this field, more is possible, as demonstrated, for instance by the so-called "waterharmonica" model [see article by Classen & Kampf, Newsletter No.10, the editor], where the last step of the constructed wetlands is used to feed the spoonbill. Concerning design and construction of buildings or motorways, there are many possibilities to reduce the negative effects on the natural environment, and even ways to increase the ecological values.


I believe that our readers will be interested to get some more information here. This is one of the issues that separate the existing "schools" of Ecological Engineering from each other.

For example, our flagship journal "Ecological Engineering" has the subtitle "The journal of Ecosystem Restoration". A title that reflects the academic roots of this field, but not necessarily the whole scope of possible applications of this "new ecological paradigm", as Bill Mitsch called it once (Mitsch 1990).

So, can you tell us a bit more about the limitations of the Ecological Engineering approach, from your view? For example, have you encountered fields while writing your book where Ecological Engineering could not be applied?


Indeed there are limitations about the understanding of Ecological Engineering in the scientific field. In my view, besides

  1. restoration of ecosystems, and
  2. development of new sustainable ecosystems, the goals of Ecological Engineering should also include
  3. the integration of technosystems and ecosystems by using mitigation measures.

It means the design and incorporating of mitigation measures that are used to reduce negative effects on nature by all kinds of civil engineering constructions.

Facilitating and stimulating ecological patterns and ecological processes can do this. Examples of the last category are: vegetated ('green') roofs, roadside and railway verges, planted buffer zones, defragmentation measures (like fauna passages in the form of ecoducts, fauna tunnels, culverts adapted for fauna passage, ecopipes...). It includes also multifunctional noise barriers, concrete walls with holes for nests of the sand martin [a bird species, AS] or wood blocks with small holes for nesting of wild bees.

This third category is mostly fully omitted in Ecological Engineering textbooks. That was one of the reasons for writing the book 'Ecological Engineering: Bridging between ecology and civil engineering' in which Ecological Engineering is presented as a much wider approach.

Fig. 2: Innovative noise barrier at a resting site on a Dutch motorway, providing both noise protection and habitat. (Photo: H. van Bohemen)


If I follow your reasoning, Ecological Engineering would not be applicable in fields where ecosystems are not involved, right? Such as, e.g., in computer science, mechanical engineering and human psychology?

Let me drill down some more on this issue: There are some people who limit Ecological Engineering to basically wetlands and similar ecosystems, others who would even include city planning and any kind of systems thinking. Some people even use Ecological Engineering as one of the options for a more ecological crop production (without excluding e.g. genetic engineering or the use of pesticides).

I strongly feel that who ever defines a term will define the perception of it in the future. So understanding where we do not use the term Ecological Engineering, or where we think it can't be used, is crucial for its perception in the public.

Can for example a genetically engineered plant be part of an ecologically engineered system? If the system alone would be the focus, why not? If however, there is an ethical viewpoint involved, then excluding this approach would be the way.

In this light, I think you have not yet answered my question regarding the limits of the Ecological Engineering approach and I would be very interested to hear what you think about this.


My central concern is the way we can find a balance between satisfying human needs as well as allowing other species to meet their 'needs'. Are we able to share our options in areas with other species living in the same area? In all areas of decision making we need ethical judgements to find out which impacts human behaviour has on other species and ecosystems and how to prevent, mitigate or compensate these impacts.

So for me, coming to your question about genetic engineering, I think genetic engineering is not part of Ecological Engineering, but within an ethical framework of Ecological Engineering we may decide that specific proposals for genetic engineering are acceptable. Here we are touching basic questions about the borders of science. Can we include philosophy and ethical considerations in our way of doing science? I think we should say yes in the case of Ecological Engineering.


What was your motivation to start working with Ecological Engineering in the beginning? Was there a key experience for you?


Trained as a horticulturist and later as ecologist and landscape ecologist, I first practiced nature conservation and understood the mutual influence between cultural and natural processes. And I experienced the effect of not being able or even being allowed to think and to talk across the borders of my field of interest.

Later my strongest interest arose when confronted with human made infrastructures (roads, power lines, railways) within natural landscapes and [when I realized] that a lot of options exist and can be designed to reduce negative effects. For me, infrastructure means: human made infrastructure - water provisions, provisions for movement - as well as ecological infrastructure at all levels of scale. So, when you look at it that way, problems caused by separate action should become part of an integrated problem solution in which at the same time, on the same spot (integrity of 'place') several problems can be solved in a fully integrated manner.

My key experiences were visits at the constructed wetlands for waste water treatment in Arcata Marsh Wildlife Sanctuary (USA), the Stensund Centre (Sweden), the Living Machines (USA, Canada) and the "waterharmonica" model (Netherlands) which all bring the concept of real recycling of wastewater all together.


Let us take a closer look at the Netherlands: Is Ecological Engineering going to become "mainstream" in the next 10 years? How many people are promoting it? Can you name a few and give examples?


If you define 'Ecological Engineering' in a wider sense, interesting steps are taking place in civil engineering and in architecture. But Ecological Engineering as a mainstream issue is further away, as economics and politics are very slow in accepting the idea that "free resources" should have a real, real, real price.

In several fields of interest some people are promoting Ecological Engineering, but there is a need for more experience, showcases and real support for ecologically engineered solutions.

Good examples are: recycling of waste, constructed wetlands, mitigation measures for crossing fauna, rehabilitation of old buildings instead of destroying them and the "waterharmonica" model (feeding spoonbills on 'wastewater'). There are only two living machines existing in the Netherlands at the moment, a third is going to be implemented. A great deal of experience has been gathered in the field of coastal management, where natural dynamics are used for protecting sandy coast lines against storms. These are all well known applications of Ecological Engineering in the Netherlands.

Fig. 3: Green roof topping the library of Delft Technical University, the Netherlands. The green roof is providing habitat for plants and some animals, helping to reduce storm runoff and protects the roof construction from extremes in temperature.
(Photo: H. van Bohemen)


Do you have a favourite example for Ecological Engineering, one that inspires you most?


The concepts of the Living Machine, urine separation technology and constructed wetlands for wastewater treatment are highlights for me. Looking at dynamic coastal management and provisions for wildlife helped me realize the great possibilities of combining human needs and safeguarding wildlife at the same time and the same spot. This basic insight has been widened by learning about all the different options of Ecological Engineering through attending conferences about Ecological Engineering during the last decades.


Why and how did you get involved with IEES?


My involvement began during a course on Ecological Engineering organised by Johannes Heeb, Bill Mitsch and Jos Verhoeven at the University of Utrecht, which ended up in the founding meeting of IEES that I also attended. This course gave me the spirit to become active in trying to widen the scope of Ecological Engineering. It made me active in getting an overview of relevant case studies.

I believe that a network of case studies published on the web, which can be easily visited is one of the means to convince people as they give possibilities for viewing the area and exchange experiences right on the spot. The case studies are part of our IEES website and the website is still open for much more case studies. So are you involved in one, please open the IEES website [http://www.iees.ch/casestudies.html] and you will find a form which can be easily filled with information about your project.


What role could IEES play in the future to help develop Ecological Engineering?


IEES should play a more stimulating role in spreading the knowledge about the usefulness and effectiveness of Ecological Engineering to reach a more sustainable society. I think the next three aspects should be dealt with:

1. A strategic paper made by the IEES together with other ecological oriented organisations should be presented at high level as well as grassroots organisations to spread the message and to obtain funds to be able to carry out a professional communication program.

2. From a scientific point of view it should be relevant to stimulate more theory development. More testing of hypotheses in other to form a more coherent theoretical background of Ecological Engineering.

3. On the practical level, more case studies should be described, presented and made accessible to an interested audience, including a framework for setting up your own projects. The case study areas should have visiting possibilities to study the examples. It should be facilitated to provide more real data for designing Ecological Engineering options.


What in your view is the main obstacle for the further development of Ecological Engineering in your country?


The biggest challenge is the further integration of different scientific fields as well as to get enough interest in the society. More working together can help to formulate hypotheses and theories, which go across the boundaries of their respective scientific fields.

For instance we can look separately at ecosystem health, human health and mental health. But would it be possible to join the different fields all together? We should also look at the economic theories and practices. In principle, economy should not be the origin of deteriorating ecological values and destroying our natural support system, which it does up till now in many, many situations. 'Free goods' are suffering and the generations after us will pay the bill. Is this right?


I have a last question: Do you "live" Ecological Engineering in some way? (some of our board members have a composting toilet at home ...)


We use rainwater for our garden, recycle paper, and glass and organic waste in our compost. Locally we travel by foot and bike as much as possible and use the train for longer distances. And we are now in the process to install a 'green' roof on our carport.

When my parents died part of the heritage has been used to form a foundation with the name of our parents to prevent using the money for consumption. The goal of the fund is to stimulate peace projects among youth. I think this is also part of sustainability and should be more widely used. It will save money for future generations as well.

Recently I got my early retirement, but I will still work one day a week at the University of Technology in Delft as a lecturer in Ecological Engineering. I hope to have a chance to transform this temporary post into a more permanent one. The Board of Directors of the university has accepted that sustainability should be one of the pillars of the studies of technology. In the building and design faculties it is already fully integrated, but in other faculties there is still a need for a more fundamental basis in the curriculum, but this is now changing. Sustainable construction and recycling of building waste are courses that have been running for years at the Civil Engineering Department. The course I am responsible for is held in the Masters of Science of Civil Engineering program and students can get a sustainability annotation. If they wish they can call themselves engineer in sustainability.

I like to end this interview with some personal wishes...

Please feel free!

A more active approach of respecting the diversity of human cultures in their respective natural systems should be a general attitude for humans and institutions.

International trade should become more involved in reducing side effects like spreading of exotic species, which in a lot of cases has been harmful to local environments.

The WTO should be more active in stimulating real sustainability, not only in economical terms but also in social and ecological ways. A strategy for local production and selling of food and vegetables are ways to reduce impacts. WTO should defend more the integrity of natural bioregions. Organisations promoting eco-cities, eco-villages, eco-parks and eco-landscapes should work more together.

Basic in all understanding is the ethical role humans should fulfil: finding a balance between their needs as well as satisfying the 'needs' of other species using scientific methods and not by pursuing ideologies or other one sighted visions of our world. The main task will be to conserve the cultural and biological diversity of the Earth, in order to have a mutual relationship with other forms of life, by using local resources, by recycling, including use of waste as a resource and using renewable energy instead of fossil fuels as much as possible.

In all applied fields there should be more attention towards more ecological sound and sustainable living. In the field of architectural design and area planning more ecological design should be realized. There is a need of integration of good places for recycling, safe places for bicycles, separation of urine and faeces, composting in a fully integrated system.

When talking about safety I'd like to say that any civil engineered or human engineered project or object (houses, bridges, cars) should be safe for the public as well as safe for the environment. This means a harmonious integration of engineered projects or objects within ecosystems at all levels of scale. The construction and the use should be as ecologically embedded as possible. If impacts cannot be prevented, effects should be mitigated as much as possible and if this is not enough the rest should be compensated.

Thanks a lot for this interview, Hein.



W.J.Mitsch, Ecological engineering: The roots and rationale of a new ecological paradigm, in: Ecological Engineering for Wastewater Treatment, by C.Etnier & B. Guterstam, 1996. 2nd edition, 480 pages, ISBN:0873719905, Lewis Publishers

W.J. Mitsch and S.E. Jorgensen, Ecological Engineering and Ecosystem Restoration,

S. van der Ryn and S.Cowan, Ecological Design,

G.C.Daily, Nature's Services; Societal Dependance on Natural Ecosystems,

N.J. Todd and J. Todd, From Eco-Cities to Living Machines; Principles of Ecological Design.

© 2005, International Ecological Engineering Society, Wolhusen, Switzerland