Lustrum - Dispuut Watermanagement

Volume 20 | May 2010 

6 th 

Lustrum 

May 21 - May 30

2 

Colofon 

Colofon Dear 

Volume 20, Number 1, May 2010 

The ‘Druppel’ is a magazine of the student society 

of water management of the TU Delft. The magazine 

is published three times a year. 

Editors 

Philip Stive 

Mark de Koning 

Rostislav Peknice 

Franca Kramer 

Robbert Martens 

Shervan Gharari 

Jop Jansen 

Design 

Philip Stive 

The ‘Druppel’ is distributed to 

all members of the 

‘Dispuut Watermanagement’ 

Faculty of Civil Engineering 

and Geosciences 

Contact 

Dispuut Watermanagement 

Room 4.74 

Stevinweg 1 

2628 CN Delft 

015-2784284 

dispuut-wm-citg@tudelft.nl 

www.dispuutwatermanagement.nl 

reader, 

It has been 5 months since you had opened the last 

Druppel of the year 2009. We are very happy that we can 

provide you the first issue of the year 2010. It is the 20th 

volume of Druppel! The Druppel has changed through 

time and you may remember the improvements that we 

introduced last year. For example the ‘Special’ - the part 

of the Druppel that is focused on one particular subject 

of water management. Our first Special was about 

remote sensing and it was published in the September 

issue. And now the second special is presented. The topic 

of this special is about the lustrum, because it is coming 

up in a few weeks and a lot has happened in the last five 

years. 

What else? As usual you an article describing the challenges 

of a Msc. thesis, the third chapter of Prof. van der 

Graaf’s fairy tale and also a reaction by Prof. Wiggers’ 

with a horror tale. Let’s compare the experience of 

these two famous men of the water management department. 

You can also find articles about the live of our 

international students , a company case report, experiences 

from China and a lot of other topics. 

And what to expect in the next issue? There will an extensive 

report on the study trip to Japan, a look back at 

the Lustrum and the symposium and typical articles like 

experience of internships or M.Sc.theses. The rest will 

be a surprise! 

We very much like to thank all contributors, authors and, 

especially Prof. van der Graaf, Prof. Wiggers, and Prof. van 

de Giesen. Philip has put a lot of effort in a new design, 

to honor the lustrum and make good use the first ever 

full color issue! 

We hope you will all like the Druppel and we are looking 

forward to hear any feedback. Thank you very much for 

all kind of remarks and notes about your view on the 

Druppel. Your opinion is very important and relevant for 

us (positive or negative). We are very proud of this issue 

and hope you enjoy reading. 

Kind regards, 

On behalf of Druppel Committee, 

Rostislav Peknice 

Druppel - Volume 20 - May 2010

3 

Table of contents 

Tanja Euser and Mark Hegnauer 

4 

From the board 

The effects of large-scale 

8 

Green roofs in Singapore 

A story by one of our 

10 

International students 

Professor Wiggers’ 

12 

Horror tale 

Koen Hilgersom 

13 

Column 

Professor van der Graaf’s 

15 

Fairy tale 

Introduction to the Lustrum special 

16 

Introduction 

Take out center fold 

18 

Lustrum program 

Where do all the Dispuut members come from? 

A few anecdotes 

21 

22 

An international bunch 

Once upon a time... 

Table of contents 

Pictures from all boards of the past 5 years 

24 

Boards 

Global problems, local solutions 

26 

Symposium 2010 

Jop Jansen and Philip Stive in Nevada, USA 

28 

Surface heat flux 

Company case 

30 

Fugro 

Nick van de Giesen on 

32 

Climate change 

Saket Pande and Markus Hrachowitz 

34 

Interview 


4 


Tanja Euser and Mark Hegnauer 

Sunshine! 

After a long winter with lots of snow and dark days, 

spring has come. Everyone seems to wake up and is 

cheerful again. During this dark winter, our committees 

have been working hard, making preparations for a lot of 

nice activities the coming months. 

First of all the people of the Druppel committee: the last 

months were spent in collecting interesting articles and 

putting up a lustrum item. Besides the usual filling, a lot 

of time is spent on making a new lay-out and discussions 

about a new logo for the Dispuut. The result is in your 

hands. 

know the title of this year is ‘Global problems, local solutions: 

different views on water scarcity’. By now most 

the speakers are invited and most of them are willing 

to present their views on the subject. You can find more 

information about the symposium on page 26. 

After the lustrum week and the following exams, a group 

of 15 students will travel to Japan with the GVR. In February 

there was an interest drink, where the students 

who are interested could subscribe. In the last months, 

a lot is achieved with organizing projects. There will be a 

visit to the super levees and flood tunnels in Tokyo. 

About the new logo, as we are celebrating our 30th 

birthday already, we thought it time to professionalize 

the logo a bit: the ‘druppel’ (droplet) in it is important 

and as you can see, is still there. We like it and hope you 

do as well. 


As just mentioned we are going to celebrate our 30th 

birthday this year and the lustrum committee has planned 

a lot of nice activities. In the last month, mails have been 

sent to invite members, old members and employees of 

the department for all activities during the lustrum week 

in the last week of May. The first one will be a reunion 

with old members: a good opportunity to meet old (fellow) 

students and find out where they ended up. On the 

26th there will be a big birthday cake during the cookie 

break, so come all and enjoy! The 27th there will probably 

an afternoon guest lecture followed by a drink. The 

week will be closed with a weekend outdoors: sailing and 

camping on and near the Grevelingen. This is only a small 

numeration, but later in this Druppel a lot of information 

can be found about the lustrum. 

The day before the lustrum starts (20th of May), the annual 

symposium will take place. As you probably already 

Flood tunnel in Tokyo 

Also a visit to a land reclamation project at Isahaya bay 

to create extra agricultural space will be included in the 

trip. On top of this Mount Fuji will be visited. The program 

becomes pretty stuffed already! After the summer 

holidays we hope to present an interesting report about 

this study trip. 

This was a whole story about the work of all our committees, 

but we should not forget our most important 

task: education. Different things have happened in the 

educational world. In the previous Druppel we told you 

about the set up of a good water minor to give civil engineering 

students the opportunity to spend half a year 

of their bachelor on water subjects. In the meantime the 

format of this minor was completed and the minor is approved 

by the educational committee of civil engineering. 


5 

So now we hope to have 15 students who will subscribe 

for the minor, so it can start at September 1st. 

Other educational matters are the course evaluations. 

You have probably seen them pass during your exams. In 

the second period we evaluated the courses operational 

water management, wastewater treatment and computational 

modelling of flow and transport. Thanks for all 

the responses we received from you: we are discussing 

the results of the evaluations with the teachers. In the 

third period we evaluated fundamentals of urban drainage, 

polders and floodcontrol, irrigation and drainage and 

bogeomorphology. The results of these evaluations will 

be ready in a couple of weeks. 

new guys (Gea, Franca and Bart) are going to take the 

places of Jop, Mark and me. I wish the new board a lot of 

good luck and a lot of fun. And for everybody: enjoy the 

sun and the summer! 

In previous times you have maybe already read about 

the partner plan we have set up. The idea of this plan 

is to make contact with other study associations in the 

field of water management in order to exchange contacts 

and information and to get to know new people, 

which is always nice. Last year we already made contact 

with the student board of IHE and a few months ago we 

also made contact with the board of Pyrus from Wageningen 

(study soil, water and atmosphere). They were in 

the neighborhood and came to our faculty to meet us. 

We had a nice conversation and decided to firstly exchange 

information about large activities (like symposia) 

and special educational project, so that there maybe 

comes a possibility to make mixed groups for certain 

study projects. 

Also mentioned in the previous Druppel are the afternoon 

guest lectures: guest lectures from companies to 

give you an overview of the possible things you can do 

after you finished your studies. Since the last Druppel we 

had 2 afternoon guest lectures: one from HKV about the 

NHI (National Hydrological Instrument) and one from 

Vitens about the treatment and extracting of brackish 

groundwater for drinking water. 

The 47 th board climbing a tree 

F.l.t.r.: Soledad, Mark, Franca, Eelco, Bart and Gea 


Yesterday we had our yearly board change again. Three 


Water drijft ARCADIS 

Wat drijft jou? 

Ondernemen in een complexe 

omge ving maar met overzicht, 

betrokken heid en verstand van 

zaken. Resultaatgericht: iedereen 

zegt het, slechts enkelen maken 

het waar. ARCADIS: infrastructuur 

– milieu – gebouwen. Los van elkaar 

maar ook integraal. We geven de 

samen leving vorm door creatief te 

zijn in onze oplossingen en 

daadkrachtig in de uitvoering. 

Als medewerker van ARCADIS 

verlaat je gebaande paden. Je bent 

onder deel van een net werk van 

zakelijke profes sionals. Ingericht 

rondom klanten, zodat deze direct 

profiteren van onze kennis en 

ervaring. 

Wij brengen ideeën tot leven. 

Jij ook? 

Waterveiligheid, wateroverlast, watertekort, water - 

kwaliteit en vaarwater. Stuk voor stuk belangrijke onderwerpen 

die mee bepalen hoe we wonen en werken in ons 

laaggelegen land. ARCADIS werkt actief aan de meest 

relevante watervraagstukken in Nederland en daarbuiten. 

Van de Deltacommissie tot de Tweede Maasvlakte, van 

Water in de stad tot de stormvloed kering in New Orleans. 

Met veel plezier en vol energie pakken we die watertaken aan. 

We maken graag het verschil. Als water ook jouw drijfveer is, 

neem dan contact op met René Teiken, recruiter divisie Water 

tel. 06-5073 6710. Kijk voor mogelijkheden voor (afstudeer-) 

stages of vacatures op onze website: 

www.werkenbijarcadis.nl 

ARCADIS heeft haar kennis op het gebied van water gebundeld. 

De divisie Water adviseert en begeleidt opdrachtgevers 

en partners op het gebied van kusten & rivieren, havens & 

vaarwegen, regionaal & stedelijk water. Sterk in strategisch 

advies, technisch ontwerp, planvorming, inrichting, modelstudies, 

procesmanagement, uitvoering en besluitvorming. 

Gericht op het resultaat. Dát drijft ARCADIS. 

Imagine the result

verleg je grenzen bij Fugro 

investigating planet earth 

Fugro verzamelt en interpreteert gegevens over het 

aardoppervlak en de (zee)bodem. Hiermee adviseren 

we de olie- en gasindustrie, de mijnbouw en de bouw. 

Onze experts werken overal ter wereld met de meest 

geavanceerde technologieën en veelal zelfontwikkelde 

systemen. Op zee, op land en vanuit de lucht. 

Werken bij Fugro betekent een veelzijdige baan met 

ruimte voor eigen initiatief, in diverse functies korte 

of langere tijd werken in het buitenland en volop 

ontwikkelingsmogelijkheden. Fugro groeit en is op 

zoek naar mensen die mee willen groeien. In 

uitdagende technische functies en stages, voor 

HBOers en Academici. 

Check je mogelijkheden 

www.fugro.com/careers

8 

The effects of large-scale 

green roof implementation 

in Singapore 

Jim van Spengen 

Green roof implementation in Singapore 

During the course period of the water resources master, 

tempting presentation sheets and stories about water 

management research abroad are passing by on an almost 

daily basis. Who doesn’t remember the Jeep and rubber 

boat pictures with the smiling and young mr. Luxemburg 

and prof. Savenije, who performed hydrological fieldwork 

using the moving boat method in Africa? And who wasn’t 

jealous on these pictures? Right, everyone was. As a part 

of the Singapore-Delft Water Alliance (SDWA), Deltares 

offered me to do my thesis on analyzing the effects of 

green roof implementation in Singapore. A great opportunity 

to perform a water management research abroad. 

Now that I have spend three out of the four months in 

Singapore, I am ready to share the experiences of my 

research abroad in the Druppel! 

On the way to sustainable urban environment 

Like several other (mega)cities, the highly urbanized 

city country Singapore faces some major urban water 

management challenges. Singapore’s main water infrastructure 

can be split up in a stormwater drainage and 

sewerage system. Their traditional stormwater drainage 

system consists of a 7000km network of rivers, canals 

and drains. This system was designed to quickly and efficiently 

convey stormwater runoff to the sea or the nearest 

water body. Despite of the fact that this concrete 

drainage system is able to effectively serve the function 

of flood control, the waterways are mostly dry throughout 

the year, have short extreme downstream peaks during 

tropical thunderstorms and in generally do not provide 

a healthy urban ecosystem. In order to have a more 

regulated flow in the canals with smoothened peaks and 

cleaner inflow, Singapore’s Public Utility Board encourages 

the implementation of decentralized developments. 

Green roofs are one of the practices in this context that 

have been piloted. Next to the expected advantages on 

the hydrological regime, green roofs also help to reduce 

the heat build up on exposed concrete roofs (urban heat 

island), while introducing an aesthetically attractive living 

environment at the same time. 

Despite the fact that implementation of green roofs has 

been boosted by Singapore’s policy makers, scientific research 

on the hydrological aspects, especially in tropical 

countries, is lacking. One of the research teams within 

SDWA focuses on analyzing the water quality and water 

quantity effects of green roofs. The goal of my thesis is 

to analyze on the quantitative effects of large-scale green 

roof implementation on the rainfall-runoff in Singapore. 

Green roof experiment setups on the rooftop of one of the University buildings in Singapore 


9 

On the way to Singapore 

From the 1 st of November until 

the Christmas period in December, 

I worked at the Deltares office in 

Delft on my literature review. During 

this period I also prepared for 

the study period in Singapore, between 

the 5 th of January and the 

end of April 2010. Since Singapore 

and bureaucracy seem to get along 

pretty well, this took me a two 

digit number of forms and signatures. 

But, I must say it was worth 

while. Although I am still sweating 

everyday because of the constant 

high temperatures and humidity, 

Singapore is a great place to study 

and live. I can finally agree that 

tropical thunderstorms can make the hydrologists part 

of me smile, after newspapers reported Singapore’s driest 

month of February since rainfall records began in 

1869 (6.3mm instead of the normal 170mm). Next to 

the study related activities I am being spoiled as a crewmember 

of a local sailing team and a player in the official 

university staff soccer team. And the good thing is that 

after sports, food stalls offer the most delicious food of 

the world for almost nothing. The population of 4 million 

Singaporeans with Chinese, Malay, Indian and mixed 

roots are friendly, helpful, humoristic and have their own 

local language: Singlish. Can, can, can, lah! 

On the way to research results 

Since the summer of 2009, the rainfall-runoff from five 

1m 2 experimental setups have been monitored very 

precisely on the rooftop of a university campus building. 

Besides a reference roof, every setup is prepared with a 

different treatment, that must delay or retain the rainfall 

in a certain way. For the purpose of my thesis, I only focus 

on analyzing the difference in rainfall-runoff between 

a reference roof and two similar extensive green roof 

setups. The rainfall-runoff from every setup is conveyed 

to their individually logged tipping bucket, which have a 

volume of 1 litre per tip. 

Green roof experimental cross section 

Parallel to the runoff measurements, I am setting up a 

one-dimensional HYDRUS model for simulation of transient, 

vertical water flow in unsaturated media to predict 

the runoff for extensive green roofs in Singapore over 

a range of events that go beyond the available measurement 

data that I use for model calibration. Think of 

simulating the runoff performance of a green roof during 

a design storm or over a longer time interval…. These 

results can really be of interest to a water manager or a 

policymaker, because in the end one can conclude on the 

rate of return of a possible pilot or project investment. 

The final goal of my thesis is to provide more insight in 

the effects of large-scale implementation of green roofs 

in a 15ha urban catchment in Singapore. Therefore, I will 

do fieldwork to map the characteristics of this catchment, 

during the last month of my stay in Singapore. A 

coupled HYDRUS-SOBEK model is then the last step 

before graduation. When you are interested in the final 

results of my thesis, you are most welcome to attend my 

thesis presentation later on this year. 

Green roof implementation in Singapore 


How can I compete with 

international students who 

don’t have a life? 

Revekka Nikoli 

10 

International students 

This is a question posed by an American student of the 

Utah University of Biology when writing a similar article 

in their faculty’s magazine in 1998. The answer that he 

came up with was that he simply could not compete with 

them. Good for him. 

Foreign, non native or international students of TU Delft; 

no matter what you call them, they all share one similar 

characteristic: they count their daily time in minutes: 30 

minutes until the lectures, 20 minutes to finish this exercise, 

10 minutes to eat, 2 minutes to grab a coffee. If you 

are planning to compete with one of them make sure 

that you start counting your time like that. Then you will 

have time for everything. 

There are many people in TU Delft, coming from another 

continent, living on a restricted budget and running 

to finish their studies on time so that their scholarships 

don’t expire. These people do NOT have a life and 

this is not their choice. Just keep in mind that there are 

students here that attend 5, 6 or even 7 courses per 

quarter in order to be sure that 

they get their degree on time. 

There is no food to wait for 

them when they come home, 

no clean clothes and actually 

no one to help with 

anything. 

My best friend is an Iranian 

student of my faculty. Do you 

know why? He just lives 

next to me. I am the only 

person he can come to, 

talk about his day because 

it takes little 

time to walk to my 

place. We sometimes 

eat together in order to 

save time when someone is 

too busy to cook. I would 

say that our relationship 

is kind of ‘necesseary’, as I 

don’t know what we would 

do if no friends lived near by to say hello once and then. 

The adventurous picture of independence that takes 

shape in your mind before you leave your country for 

your master’s, turns into an Indiana Jones’ adventure 

when you start visiting TU Delft. 

“ 

Studying in Delft 

is an Indiana Jones adventure 

” 

My true story is that the first quarter I had lectures 

every day from 8:45 to 17:30 for only 4 courses and 

although Friday was free on the first week, they managed 

to squeeze some full-day experiments in the remaining 

ones. Thank God because people can get really spoiled 

otherwise! The weekend and the evenings were totally 

devoted to homework and exam-preparation. What we 

sometimes joke on with international friends is that as 

long as we survived the first quarter we can survive 

through anything. And this is because when we came 

here, no one really knew how to work or study and the 

time we had to learn (between classes) was too short. So 

where is the space for social life? 

For those who think that I am only presenting the dark 

side of the picture, here is the happy side: Delft is a wonderful, 

cute city; TU Delft is the best University that could 

teach us water issues and in Holland everyone speaks 

perfect English which makes you feel secure wherever 

you are. Living on your own and making friends from all 

over the world is exciting too! What I wanted to achieve 

with this text is just to make people aware of students 

who really have a hard time with gathering 27 credits in 

a quarter (yes, I know a few people like that). What you 

can do is propose them a break next time you see them 

running. Spring and summer will help you convince them. 


Water en veiligheid 

Vestiging Lelystad 

Botter 11-29 

8232 JN Lelystad 

Vestiging Delft 

Electronicaweg 12 

2628 XG Delft 

Zusteronderneming 

HKV HYDROKONTOR 

Dennewartstraße 25-27 

52068 Aachen (Duitsland) 

Correspondentiegegevens 

Postbus 2120 

8203 AC Lelystad 

Telefoon: 0320 294242 

Telefax: 0320 253901 

E-mail: info@hkv.nl 

Internet: www.hkv.nl 

HKV LIJN IN WATER doet onderzoek naar water 

en veiligheid en adviseert de Nederlandse 

overheid, provincies en waterschappen. 

Wij vinden het van belang dat besluiten over 

onze waterveiligheid worden gebaseerd op 

solide overwegingen en onderzoek en niet 

op dogma's of starre uitgangspunten. 

Dat onze aanpak aanslaat, blijkt uit de groei 

van ons bedrijf en onze tevreden opdrachtgevers. 

Die opdrachtgevers zitten niet alleen 

in Nederland, maar in toenemende mate ook 

in het buitenland, met name in Duitsland, 

Oost Europa en Zuid-Oost Azië. 

Wij zoeken studenten en nieuwe collega's die 

ook hun steentje willen bijdragen aan een 

veilige en zorgvuldig beheerde omgeving. 

Wij kunnen studenten volop mogelijkheden 

bieden voor: 

afstudeerprojecten 

promotiestudies 

grensverleggende onderzoeken

The horror tale of professor 

Wiggers 

Jan Wiggers 

12 

Horror tale of prof. Wiggers 

The survival of the section of sanitary engineering. 

One of the most rousing actions in my professional career 

was what professor van de Graaf in his article in 

Druppel Volume 19, September 2009 and Volume 19 November 

2009, has called the dismantling of the Laboratory 

of Sanitary Engineering. 

In the early nineties it was my task to reorganize the Section 

of Sanitary Engineering. Due to newly defined rules 

by the board of the university it became quite clear that 

the laboratory of the section was not able to generate 

the money it needed for its operations. The yearly deficit 

on the budget of the section caused by the laboratory 

was around one million guilders (Euro 450.000) which 

at the time was a significant amount of money. If nothing 

was done there was a real threat that the whole section 

could be erased from the programme of the faculty. 

In consultation with my colleges (professor van de Graaf 

and professor van Dijk) I decided to develop a two 

pronged approach. Firstly to reorganize the laboratory 

such that it could support the education of the students 

in a financial viable way and secondly to stop the research 

related activities of the laboratory. (Professor van 

de Graaf erroneously mentioned that the whole laboratory 

was dismantled.) The first task was the easy one. 

Together we quickly arrived at a sensible solution. The 

second task was horrific in its execution and in its implications. 

Several colleges had to be told that they could 

no longer be employed by the section. At that time it was 

the common opinion that having a government job was a 

job for life and suddenly this proved to be no longer true. 

It was a shock for most of them. I tried together with the 

former secretary of the faculty (he was of great help) 

to find other positions for the people involved. A few 

could be incorporated in the educational programme or 

offered an other position in the section, a few could be 

transferred to other laboratories, some were near the 

end of their career and could be prematurely pensioned 

but for some it was sadly dismissal. A few brought up 

their case to the court of labor. The sessions I had to attend 

were emotional and gripping. All but one lost their 

case and this was the person I knew the least about. So 

in consultation with the secretary of the faculty I decided 

to ask him what was the job he preferred. He told me 

his ambition was to start a business with a French fries 

mobile van!! By some “clever” maneuvering with budgets 

the university was able to purchase him one. Ironically it 

was the least costly solution. 

Fortunately some of the obsolete equipment I was able 

to sell to other laboratories. 

I never have been able to consider the reorganization of 

the laboratory as being a fairy tale! 

The section got of the black list of the faculty. Indeed, as 

professor van de Graaf mentioned, it opened the way to 

the re-deployment of the section. It proved that the focus 

on intense cooperation with the outside world was 

bearing fruits. Two years after the restructuring, the section 

was honored with four eights in the rating of the 

international commission that judged the performance 

of the various sections of the university. The section was 

rated to be excellent. I understand that this is still the 

case for which I congratulate my former colleges. 


Drinking to a new cooperation 

in the orient 


When you want to cooperate with another company or 

institute you have to come in contact and get to know 

each other. Whether you come from the east or from 

the west: this is always the case. But when it comes to 

the way in which people get to know each other, there is 

a large ocean of difference in between. 

Koen visiting a ‘hutong’ in a ‘riksjah’ 

At the end of March professor Van de Giesen, fellow PhD 

student Congli Dong and I visited China to look for possibilities 

to cooperate with an institute in China for our 

research on the monitoring and modelling of salt water 

intrusion in deltas. We want to use our methods in both 

the Rhine delta and the Yellow river. Especially for the latter 

their data of the river basin but also their experience 

with other monitoring techniques could be of great use 

to us. From our side we can deliver a new monitoring 

technique for groundwater seepage as model input and 

new techniques of future scenario assessment. 

After arrival at the airport we were awaited by a large 

Chinese delegation. We travelled by ‘middle large’ bus 

(larger than a van, but not yet a real bus) to a place for 

lunch. This is where the first large surprise came in. For 

just lunch we were taken to a hotel underway where a 

large dining room was ordered and several waitresses 

provided us with a lot of delicious Chinese food. With 

this eating also a lot of drinking was involved. During a 

Chinese dinner one can bring out a toast to one or more 

persons at the table and then drink together with these 

persons. The person who toasts may decide how much is 

drank, but in most of the cases this means that the total 

glass is emptied (as they explained it to us: ‘bottom-up’; 

as Dutch students know it: ‘adten’). During the lunch we 

just drank beer, but the concept of dinner I just explained 

applied to every dinner during the rest of the week and 

at dinner most of the times also wines with alcohol percentages 

up to 66% were served. You can imagine that 

after a view glasses people start to get really drunk. 

And that is exactly where the Chinese want to get acquainted. 

Getting to know each other in their eyes can 

be only done on the basis of many and good food and 

drinks, things that are also important to the Chinese in 

daily life. I have to say: this is just one of the many aspects 

of Chinese culture that is really different from the western 

culture but it is a striking one. I wonder how they 

will like the kroketten in the canteen on the 6th floor 

when they come to the Netherlands… 

Serious business in China 

13 

New cooperation in the orient 


Our passion for water knows no bounds 

The 1,700 people working at Vitens have a dream: we want everyone to have access to top-quality 

drinking water. Whoever you are, wherever you live. That is what drives us to work on innovations, 

sustainability and reliable operations. In the Netherlands and beyond. Vitens employees share their 

passion for water with people all over the world. And they make an active contribution to water 

supply projects in countries as far afield as Mozambique, Ghana, Vietnam and Mongolia. 

Are you looking for a job with real meaning? With a product that is literally of vital importance? 

Then Vitens is the company for you. You can find job vacancies on our website. 

www.vitens.nl

Fairy tales of professor 

van der Graaf (3) 

Jaap van der Graaf 

The future urban water cycle 

The previous contribution, on sustainability, ended with 

the question how the urban water cycle will look like in 

the future. Therefore we must combine the outcomes 

of the DTO-study, other investigations towards new 

technologies and practical engineering facts. With the 

last item I mean that the practical applicability of various 

new ideas or concepts have to be included in the further 

decision making. When, for example, some researchers 

promote small scale units above large scale treatment 

plants because with small scale units the “extremely high 

costs of sewerage systems’ are avoided, it is the task of 

a sanitary engineer to make designs and calculations in 

order to prove this argument is true or false! (by the 

way: it is false!). 

Coming back to the DTO-study, which was elaborated 

in 1994, the most important improvements in the urban 

water cycle were investigated and evaluated; this leads to 

following conclusions: 

• Improvements of parts of the water cycle, as the 

connection of remote discharges onto sewerage 

systems, the renovation of old sewerage systems 

and the optimization of water production and 

wastewater treatment, are still of great importance. 

• Reduction of emissions through sewer overflows 

and effluent discharges should be minimised. 

• The produced waste sludges should be handled as 

far as possible and eliminated. 

• The reduction of the water consumption is an useful 

tool but does not contribute much to the total 

sustainability. 

• Also eliminating surface runoff from entering the 

sewer is helpful. 

• Small scale solutions, do not contribute to the total 

sustainability mainly due to operation and maintenance 

problems. 

During the last 15 years this strategy still remained valid. 

Many developments and new techniques lead to a further 

closing of the water cycle and improvement of the 

removal of the various harmful constituents; furthermore 

during the last decade the concept of completely 

closing the water cycle has been adopted in many situations; 

re-use of effluent plays an important role in this 

concept. 

An example of this concept has been realised in Singapore! 

Singapore is probably the first city in the world 

that has developed and implemented an integrated approach 

for the urban water cycle. Thirty years ago the 

situation was very miserable: all the drinking water had 

to be imported from Malaysia, the rivers were heavily 

polluted, in rainy periods large parts of the city were 

flooded, the bucket-system for night-soil collection was 

running at its end; briefly, a sanitary and environmental 

chaos. 

During the last thirty years the situation has been 

changed drastically. For the production of drinking water 

four resources are available now: rainwater (runoff) that 

is collected locally, imported water, treated wastewater 

(NEWater) and desalinated seawater. All consumers have 

access to sufficient water. The used water is collected 

for 100 % through an extensive collection system and 

transported to centralised wastewater treatment facilities. 

After membrane filtration (ultra + reverse osmosis) 

this water is supplied to the industries or added to the 

fresh water storage basins. The rainwater is collected by 

a separate open system, which is not subject to discharges 

of garbage, and also transported to the fresh water 

basins. In total it is an almost completely closed system 

with maximum removal of pollutants at the right points. 

Because of the clearly managed organisational aspects 

the total costs of the urban water cycle are fairly reasonable 

and certainly not higher than in the Netherlands. 

Singapore claims to be an example for the future megacities 

all over the world; they are really making business 

from their water cycle! 

15 

Fairy tales of prof. van der Graaf 


Introduction 

30 years of Dispuut Watermanagement, time for our 6th lustrum! Many of you might still have one of the previous 

lustrum books covered in dust lying somewhere in a moist cardboard box on the attic together with your beloved 

Calculus. To save all of you some storage space we decided to do things a little different this time! Since our Druppel 

has become a brilliant looking glossy magazine and time nowadays is a sparse good for the modern 2010 student we 

took the opportunity of producing a beautyful special Lustrum Edition of our watermanagement magazine. In these 

extra 10 pages of joy and celebration you will find some history, memories, old boards and lots of pictures. Besides 

that we took the opportunity to create a take-out centerfold which hopefully will decorate every watermanagement 

house throughout the world. 

Time has flown by since the official start-up meeting on the 22 nd of May 1980 was held and Hans Waal was chosen to 

become the first chairman of “het Dispuut Gezondheidstechniek”. Over the years the name changed several times to 

become Dispuut Watermanagement as it is right now. With all these name and logo changes also activities changed. 

What started out with the still existing borrels, lunches, meetings and trips soon became an even more exciting busy 

schedule stuffed with BBQ’s, Afternoon Guest Lectures, Symposia, Master Introduction Days, Cookie Brakes etc etc… 

16 

During 30 years and 46 boards the Dispuut evolved from a group of super enthusiastic pioneers to a bunch of semiprofessional 

directors who try to make sure both students and staff-members keep their affinity with everything concerning 

water management at the TU-Delft. Whether through a beer, an interesting paper, lectures or freshly grilled 

chicken at the annual BBQ. 

Introduction 

Also members and old-members who left the university to explore horizons beyond that one of glowing greenhouses 

are offcourse not forgotten. From the 20 th of May until the 30 th of May there will be a period of activities for which 

you already received an invitation. The 10 days start out with a symposium and an unforgettable Reunion Party with 

BBQ. The week after there will be cake, cookie brakes and of course a drink! To finalize all the celebrations there will 

be a weekend full of sailing, bbq and “gezelligheid” on lake Grevelingen. 

We as a Lustrum committee hope you will all join and enjoy the activities and help to make this another unforgettable 

week in the Dispuut Watermanagement’s history. 

Jop Jansen 

on behalf of the Lustrum Committee 

6 th Lustrum Special

An international 

bunch 

After graduation everybody goes there own way to explore new horizons. Some stay in the Netherlands, some obviously 

go abroad. But where did everybody went to? In the figure below every orange country homes at least one 

watermanager related to the Dispuut. The majority obviously comes from the Netherlands. But especially the last 

couple of years there is a strong increase in the number of foreign students. Many guys and girls from China, Spain and 

Greece came to Delft to study at the TU-Delft and enjoy the Dutch life in Delft. 

As you already might have noticed on previous pages some more statistics about the Dispuut are plotted throughout 

this Druppel. How many people are or were active members, which gender had the upper hand, do board members 

stay more close to the Dispuut than non board members… Now you know! 

Statistics 

21 


Once upon 


In this Druppel, amongst other activities this year, we celebrate the Dispuut’s 

6 th lustrum. This means that the Dispuut already has 30 years of 

history. I think this is a history to be proud of. As one of the editors of the second Druppel of 2008 I had the chance to 

dive into this history. This brought forward nice stories from for example our honorary members as well as from our 

former board members. The nice thing is that these board members, but also other members actively involved, are the 

ones that have written this history. Many activities of the Dispuut as we know them today have once been introduced 

by these board members. One and a half years a go with the 43 rd board we introduced the weekly cookie break. The 

first time it was still exciting whether students and staff would find their way to this new activity. Now we know that 

this move was a success. Still, every week the cookie break is a social activity where staff and students meet each other. 

Following from these social activities but also the Dispuut’s task to watch the quality of education, the Dispuut is also 

one of the sources for a good future for those graduating at this department. Whether alumni are going to work at 

an engineering company or they will have a scientific career, in the Netherlands or abroad: part of the foundation of 

success lies in the education they got and the people they met. That’s the way the cookie crumbles… 

22 


Nikolaas van Balkom 

I remember it as the day before yesterday… The study tour 

along the Ebro River in Spain. It was Wednesday the 29 th of 

April, the day Manchester United played 1-0 against Arsenal in the semi-finals of the Champions League. That day, 

two very experienced hydrologists took us to river Ebro’s water source: the mountains of the Pyrenees. Our guides’ 

names were José and Carlos. José and Carlos are not 

only colleagues, they also are very good friends. Both 

already reached an age where normal people would 

retire. But they were not thinking about that. It was 

fantastic to see how the two friends where enjoying 

their work and were not thinking about when 

to stop. 

Later that evening, when we came home to our hostel 

in Zaragoza, the group was exhausted. We knew 

that the next day we had to wake up at 7 in the 

morning for an other excursion. Still some students 

decided to go to the city. Off course it became very 

sociable and before we knew it was 6 o’clock already! 

Then I understood why Jose and Carlos were 

still working, having a good time with friends makes 

you forget the time! 


a time... 

When I was asked to write a short piece about an activity of the 

Dispuut in the past few years and maybe add a nice anecdote I Cheryl Bertelkamp 

was thinking about the study trip to Argentina, company cases, active member’s day etc. There are of course many 

nice stories to tell but something I remembered very well was the daytrip to Belgium with the board (Leon, Evelyn, 

Joanne, Frederik, Ruben C and me) in 2007. Evelyn 

and Leon organized a nice tour with a picnic 

in the park and some sightseeing in Antwerp. 

After that we decided to sit by the canal to rest 

for a little bit. Everything was fine until Rubens 

shoe slipped off and fell in the canal, about 2 

meters down in the water. We had to ‘borrow’ 

a huge rod and made several attempts to catch 

the shoe. Eventually we caught it and it was easy 

for people to see where we went as Ruben was 

leaving a track with his wet shoe... 

Stijn de Jong 

In the summer of 2008 the GVR (the big far trip) to the country of Evita, Maradona, 

Tango and the finest steaks took place. Together with 20 enthusiastic persons in one 

bus and a number of nice activities the right ingredients for an unforgettable time. The moment I remember the most 

is an excursion to a rain water harvest system near Santiago del Estero. After a 30 minute drive over a dirt road we arrived 

at a few small farms 

where we experienced 

the hospitality of the 

Argentinean people. Although 

it was obvious that 

the families living there 

didn’t had much to spent, 

they prepared a barbeque 

wherefore they sacrificed 

a dozen goats. Together 

with the locals we enjoyed 

this great meal and 

a delicious ‘spekkoek’ for 

desert. Moments to never 

forget! 

23 



24 

Boards 37 through 41 

Boards from the 


past 5 years 

Boards 42 through 46 

25 


Surface heat flux in Reno 

Nevada, USA 

Jop Jansen & Philip Stive 

26 

Surface heat flux in Reno, Nevada, USA 

A few days before the start of the experiment... We wake 

up in our appartement in Reno, and have our Subway 

style breakfast as usual. Prepared to go to the campus 

in our monstrous ’92 Honda Accord we open the front 

door. The doorway is blocked by 2 feet of snow, so much 

for the perfect weather in Reno, which is “always dry and 

sunny; ideal for your soil heat flux experiment”... With 

the help of a snowblower and some well overpaid blokes 

willing to play with it, we eventually did our experiments. 

This article describes our academic findings during our 

2,5 months stay in ‘The States’. If you want to hear about 

our social findings, you probably know where to find us... 

Surface heat flux is an important component of the surface 

energy balance (SEB): 

Rn 

= G + LE + H 

Eq. [1] 

Where R n 

is the net radiation, G is the surface heat flux 

density and LE and H are the latent and sensible heat flux 

densities, respectively. 

Surface heat flux is often regarded as a very small and 

sometimes even neglected component of the energy 

balance, which can lead to large errors in models for instance. 

Another misconception, often in practice, not so 

much in theory, is the small spatial variability of surface 

heat flux. 

We performed research on a method to relatively easy 

determine G over time and a significant spatial range, 

with the use of passive Distributed Temperature Sensing 

(DTS). With the use of a self designed and constructed 

plow system, fiber-optic cables at three different depths 

(1, 6 and 11cm) were installed in January 2010 in Reno, 

Nevada. 

The method presented here uses DTS. This technique 

consists of a fiber-optic cable and a device that sends laser 

pulses through this cable. The specific technique used 

here is called Raman backscatter Distributed Temperature 

Sensing. Part of the laser pulse is being reflected 

back to the instrument and by measuring the return time 

the distance to the reflection point can be calculated. 

Most of the reflected light comes back with the same 

frequency, however part is coming back with a different 

frequency, the so called Raman frequency. It consists of 

a part with a lower frequency and one with a higher 

frequency, the Stokes and Anti-Stokes backscatter respectively. 

The amplitude of the Stokes backscatter is not 

temperature depended, however the amplitude of the 

Anti-Stokes is highly temperature depended. By calculating 

the ratio between the Stokes and the Anti-Stokes the 

temperature can thus be calculated. Eq. [2] shows the 

relationship between the Stokes and Anti-Stokes and the 

temperature. 

T ( z) 

= 

z 

∫ 

β + ∆ α( z ') dz ' + ln 

0 

γ 

+ 

I 

( − ) 

I 

Eq. [2] 

Gamma and beta are parameters specific for the used 

instrument and setup (e.g. depended on ambient temperature) 

and alpha is the attenuation, e.g. signal loss, that 

occurs along the fiber optic cable. 

If one wants to calculate heat flux from temperature 

measurements, thermal properties of the particular soil 

need to be known. These properties are related to the 

unkown moisture content. 

Since only temperature measurements are available a 

Matlab model, developed by Susan Steele-Dunne, is used 

to estimate diffusivity from the measured temperatures 

at three different depths. From this diffusivity, thermal 

conductivity, heat capacity and moisture content can be 

determined. 

The diffusivity can be calculated via the diffusion equation: 

∂T 

∂t 

= D 

( θ ) 

2 

∂ T 

2 

∂z 

Eq. [3] 

Druppel - Volume 20 - May 2010 

H2O

Thermal conductivity on its turn 

is dependent on moisture content. 

When the moisture content is unknown 

thermal conductivity has to 

be obtained from the relationship between 

thermal conductivity (K), diffusivity 

(D) and heat capacity (C). 

D 

( θ ) 

K 

= 

C 

( θ ) 

( θ ) 

Eq. [4] 

Surface Heat Flux [Wm−2] 

200 

150 

100 

50 

0 

Surface heat flux along cable 

Jan−30−10 00:15 

Jan−30−10 09:00 

Jan−30−10 11:30 

Jan−30−10 12:30 

Heat capacity is a simple linear function 

of soil moisture: 

−50 

0 10 20 30 40 50 60 70 80 

Distance along cable [m] 

Figure 1: Surface heat flux along the cable 

ρ ρ ρ 

C = n(1 − Sr ) 

aca + Srn wcw + (1 − n) 

scs 

Eq. [5] 

From lab experiments the McCumber-Pielke model for 

the relation between soil moisture and thermal conductivity 

best matches our soil. From these three relations 

soil moisture and thermal conductivity can be computed 

directly from temperature input only. 

With these parameters and the three temperature 

measurements along the cable, two layer-average heat 

fluxes can be calculated, one at 4,1 cm and one at 9,0 cm 

depth. This soil heat flux is proportional to the temperature 

change over the depth, according to Eq. [6]: 

G 

z 

T 

= −K( θ ) 

∂ 

∂z 

Eq. [6] 

Where K [W m -1 K -1 ] is the thermal conductivity for a 

unit area. These fluxes however do not accurately reflect 

the heat flux occurring at the surface, the so-called 

surface heat flux (G s 

). They need to be corrected to reflect 

the change in heat storage in the layer(s) between 

the surface and the depth of the calculated soil heat flux 

(G z 

). This relationship can be expressed as: 

G = G + S 

s 

z 

∂T 

S = C ∆z 

∂t 

where Eq. [7,8] 

C is the layer averaged heat capacity (J m -3 K -1 ), dT/dt is 

the average rate of temperature change of the layer (K 

s -1 ) and Dz is the thickness of the layer (m). 

The method we used in this research directly enables us 

to calculate this change in heat storage due to the presence 

of fiber-optic cables in the specific layers. 

The results show that with the use of high resolution 

temperature measurements, a good estimate in surface 

heat flux can be made. We have found spatial variability 

in surface heat flux of up to 100% within a 15 meter span 

(figure 1). What causes this spatial variation in surface 

heat flux can remain a point of discussion. Variations can 

be caused by differences in soil moisture, soil structure 

or cable depth. The latter is especially interesting in this 

case, since it is assumed to be negligible compared to the 

influences from the soil like moisture and structure (for 

a discussion see the paper in the near future, or come 

and talk to us.). 

The standard field technique to measure surface heat 

flux, using heat flux plates can cause large errors due to 

the existence of the large spatial variability shown here. 

This can lead to large errors in models, for example the 

use of heat flux plates in the calibration of remote sensing 

models with large grid sizes. 

In the near future we hope to present and publish a paper 

about this topic in cooperation with Prof. Nick van 

de Giesen, Dr. Susan Steele-Dunne and Prof. Scott W. 

Tyler from the University of Nevada, Reno. Comments 

and suggestions are more than welcome. 

27 

Surface heat flux in Reno, Nevada, USA 


Introduction 


This year the topic of the symposium will be water scarcity in all its forms: both 

problems and solutions. The aim of this symposium is to give, in the morning session, 

an overview of problems caused by water scarcity at different scales (World, Europe, developing countries) and how 

the scientific community is reacting to them. Then, in the afternoon session, separate workshops (two sessions) will 

take place in relation to solutions for specific issues. Different topics have been selected in the domains of Drinking 

Water, Water Resources and Wastewater. 

We are glad to announce that professor Jules van Lier will be the chairman of the day for this symposium. 

Practical information 

When Thursday May 20 th 2010, 9.30 – 17.00 

Where 

Faculty of Civil Engineering Room E, TU Delft 

Prices 

€ 7,50 Student members Dispuut Watermanagement 

€ 10,00 Other students 

€ 35,00 Old members Dispuut Watermanagement and members of the Water 

management department 

€ 70,00 Externals 

How to subscribe 

Send an email to dispuut-wm-citg@tudelft.nl 

28 

Water scarcity 

Experts and media are talking about problems and solutions around water 

scarcity, but do you know what water scarcity is and what it concerns? What 

are the causes, consequences and possibilities to deal with it? 

According to the Cambridge Advanced Learner’s Dictionary: 


Water noun - a clear liquid, without colour or taste, which falls from the sky as rain and is necessary for animal and 

plant life. 

Scarcity noun when something is not easy to find or get 

Asking a researcher would probably add the following questions: 

• When was the last time there was sufficient water with sufficient quality? 

• During which periods is there enough water? 

• What is the current quality of the water? 

And asking an engineer would possibly add the following questions: 

• What is the required quality for the water: waste water is not so scarce as drinking water. 

• What is the required quantity for the water: only drinking or complete irrigation? 

As you can see, there are a lot of different aspects in water scarcity. On the other hand, a lot of people associate 

water scarcity with problems: problems on different levels, but problems that must be solved. So the symposium is a 

nice opportunity to get an overview, by well known specialist, of all the different problems and possible ways to deal 

with them. 


Global problems, local solutions 

Preliminary day program 

09:00 - 09:30 Welcome 

09:30 - 10:00 Opening and introduction 

Prof. dr. ir. J.B. van Lier (TU Delft) 

10:00 - 10:45 General problems on water scarcity on a global scale 

10:45 - 11:00 Coffee break 

11:00 - 11:45 General problems on water scarcity focused on Europe 

Drs. A.E. Jansen (TNO) 

11:45 - 12:30 General problems on water scarcity focused on developing countries 

G. Rundberg (World Waternet) 

12:30 - 13:30 Lunch 

13:30 - 14:15 Workshops round 1 

Drinking water: Drinking by the wind 

C.A. Averink (Hatenboer – Water B.V.) 

Wastewater: 

Productive use of sanitary flows: technological challenges in wastewater treatment and 

sanitation 

Prof. dr. ir. J.B. van Lier (TU Delft) 

Water Resources: Remote Sensing for Water Accounting of Closed River Basins 

Prof. dr. ir. W. Bastiaanssen (Water Watch) 

14:15 - 14:30 Coffee + change 

14:30 - 15:15 Workshops round 2 

Drinking water: Removal of micro pollutants in Drinking Water 

Wastewater: 

Water Scarcity solutions in agriculture 

Dr. ir. F. Huibers (WUR) 

Water Resources: Policy arrangements for water scarcity in the Netherlands: effects for all water users 

J. ter Maat (Deltares) 

15:15 - 15:30 Coffee 

15:30 - 16:15 Final discussion 

16:15 - 17:30 Drinks 

More information can be found on www.dispuutwatermanagement.nl. 

29 



Company case Fugro 

December 11 th 

Eelco van der Pal 

On December 11 th a company case took place. This time 

Fugro organised it so we travelled to the head office in 

Leidschendam. With the 5 participants we planned to go 

by train, but unfortunately the train had a delay of 25 

minutes. After finally arriving at the destination we were 

welcomed and introduced to the program of the day. The 

intention was to vary between presentations about the 

company Fugro and to solve and discuss different soil 

related problems. 

30 

Fugro company case 

The first case was about the rebuilding of a city centre. 

Provided were soil characteristics which we could 

use for the design of the foundation. After a discussion 

and an explanation of the two supervisors a presentation 

was given about one of the different departments of 

Fugro. Fugro is an international oriented company which 

works with 13,600 employees in over 50 countries. Fugro 

works onshore and offshore in the fields of geotechnics, 

survey and geosciences. What most people don’t 

know is that Fugro also has a Water Services department 

which is very closely related to our study. 

The provided lunch was delicious. At lunch time also the 

managers of different departments were present so it 

was possible to have conversations about possible career 

options at Fugro. After lunch it was time for work 

again. The subject of the second case was the building 

of a new hospital. Now the group was split into two 

groups, one group was responsible for finding a solution 

for groundwater problems, the other group was responsible 

for the energy supply of the building. 

Working on the second case 

The hospital had to be located in an area with high 

groundwater tables so with provided soil and area characteristics 

a specific type of drainage system had to be 

designed. The energy supply had to be realised in a sustainable 

way so a thermal energy storage system had to 

be designed. 

After presenting the results to the other group the 

time had come for another nice part of the program: 

the drinks. When we were discussing the day together 

with the staff and the also present hydraulic engineering 

students we found out that it was actually a very instructive 

day. Not only the cases made us think about real life 

problems, also we found out Fugro is much more related 

to water management than we thought before. 

“ 

Fugro is much more related to 

watermanagement than we thought 

” 


PWN helpt. 

PWN Waterleidingbedrijf Noord-Holland heeft bijna 90 

jaar ervaring op het gebied van drinkwater maken en 

leveren. Die ervaring deelt PWN graag met anderen 

waar ook ter wereld. PWN gelooft in het overdragen 

van kennis. 

In Rwanda (Afrika) helpt PWN waterbedrijven die 

ernstig hebben geleden onder de oorlog. Ze worden 

gerenoveerd, waarbij de plaatselijke bevolking wordt 

ingezet. Zo snijdt het mes aan twee kanten: betrokkenheid 

en een beter bestaan. 

Daarnaast worden ook bestaande waterbedrijven 

gerenoveerd. 

De hulp van PWN is niet vrijblijvend. Elk betrokken 

bedrijf moet zelf ook hard aan het werk. Om dat te 

kunnen sturen neemt PWN van elk te renoveren 

waterbedrijf tijdelijk de helft van de aandelen over 

totdat ze weer optimaal draaien, water leveren en dus 

weer inkomsten krijgen. Zo komt het geïnvesteerde 

geld terug bij PWN en kan dit opnieuw worden ingezet 

voor een renovatieproject. 

In Indonesië helpt PWN o.a. waterbedrijven die door 

de tsunami zijn getroffen, met hun wederopbouw. 

Kijk voor meer informatie ook op www.pwn.nl/internationaal

Climate change and 

sabbatical leave 

Nick van de Giesen 

32 

Sabbatical leave and climate change 

According to the popular press, climate change is no 

longer an issue. That means I can relax and go on sabbatical. 

Actually, I have already left, and will be gone until 

mid-August. On 1 March, I started at the Ecole Polytechnique 

Fédérale de Lausanne (EPFL) in Switzerland, right 

on beautiful Lake Geneva. Many people interpret sabbatical 

leave as some kind of vacation so they ask you to 

do all kinds of other things. Perhaps that was also why 

Druppel asked me to write a short piece on my sabbatical 

experience and, if I wanted, to explain further my 

views on the recent climate change “scandal”. 

There is not too much I can say yet about the sabbatical 

feeling. During the first month, I spent time in Brussels 

and Princeton. I also visited Delft for two days, as I plan 

to do at the end of each month. 

“ 

We are certain that we don’t 

know anything 

” 

From Delft, I traveled to China where I am presently attending 

a workshop in the framework of a new NWO 

project. So during the first month, I spent exactly five 

working days in Lausanne. That means I have not yet 

reached that greater inner peace that will hopefully come 

to me before the summer is over. What I did notice during 

these few days was that one can actually get an awful 

lot done when you don’t spend eight hours per day in 

meetings. I even had some nice new thoughts, both about 

the bigger scheme of things and about some practical 

experimentation I hope to do during the coming months. 

If this small sample is indeed a sign of things to come, the 

coming few months will be very productive indeed. 

Now about “Climategate”. As far as I know, I am the only 

scientist at TU Delft who was a co-author on the last 

IPCC Assessment Report. The process of writing this 

report is a very careful one. There are drafts, reviewers, 

editors, etc. Every step along the way is documented 

and public. That does not mean that there will be no 

errors. One of my favorite expressions is that a camel 

is a horse designed by a committee, so the more people 

are involved, the better the chances that something may 

go wrong along the way. Still, the process follows the 

standards of peer review as is usual in the scientific community. 

When the whole “scandal” broke loose, I actually 

went to the IPCC website to see what my comments 

had been on one of the drafts and how these comments 

had been accommodated. To be honest, many of my central 

comments were not accommodated in a way that 

I had hoped for. What I was happy about was that my 

remarks concerning the almost complete uselessness of 

General Circulation Models (GCMs) where it comes to 

water resources was included and put at or near the top 

of conclusions. Unfortunately, when I picked up the final 

report, this text was almost at the bottom of the recommendations 

and had been severely cryptified: 

“[…] quantitative projections of changes in precipitation, 

river flows, and water levels at the river-basin scale 

remain uncertain (very high confidence)” (AR4, WG II, 

Ch.3) 

I had hoped for a statement like: “We are very certain 

that we don’t know anything.” I was disappointed, especially 

because this was a missed change for the water 

management community to put some pressure on the 

climate modelers. Climate modelers make temperature 

models and they don’t care what happens to the hydrological 

cycle. Just like we, until recently at least, built hydrological 

models that worried about the water balance 

but not about the temperature of the water. 

So does this make the IPCC report invalid? Does this 

mean we do no longer have to worry about anything? 

In my opinion, the main conclusions of the IPPC report 

stand. Temperatures have risen over the past century, as 

have CO2 levels. It is very likely that these two observations 

are related. If I remember correctly, the IPPC 

attached a “very high confidence” label to these statements, 

which mean they think that the likelihood is in the 

order of 95%. The reason for this high level of confidence 

is that scientists have not been able to build models or 

think of any physical process that could mimic a similar 

temperature rise without taking the increased levels of 

CO2 into account. So, yes, in my opinion, we should try 

very hard to reduce our CO2 output into the atmosphere. 

This opinion would probably not change much if 

the confidence were as low as 5%. If an airplane had a 5% 


chance of crashing, I would not get on, and, as they say, 

there is no Planet B. (I recently heard a very Swiss argument: 

Save the Earth, it is the only planet with chocolate!) 

A paleoclimatologist once explained to me that the 

“ 

last time the Earth’s atmosphere had a CO2 level as high 

as the present one, and was in thermal equilibrium, there 

was no ice on Greenland. So, although models may differ 

in the speed with which this warming would take place, 

the final state is relatively clear. Perhaps the most scary 

thing is that, in the past, there was always first a rise 

in temperature, followed by increased CO2 levels. This 

time, CO2 comes first so we really have no idea how 

fast things may actually go. Do we really want to push this 

complex Earth system to the limits? 

Do we really want to push this 

complex Earth system to the limits? 

” 

Or should we rather shoot for solar energy that will be 

too cheap to meter and obtain some political independence 

at the same time? These are not questions I have to 

think about for a long time, so I can spend all my energy 

on my sabbatical. 

33 

Wij zijn een adviesbureau met veertig 

hoogopgeleide medewerkers, afkomstig 

van verschillende universiteiten. We zijn al 

tien jaar actief voor overheden, 

bedrijfsleven en kennisinstituten. 

In samenwerking met onze klanten, zijn 

wij continue op zoek naar originele en 

creatieve oplossingen voor watervraagstukken. 

Sabbatical leave and climate change 

Heb jij kennis van water, een eigen 

mening en ben je op zoek naar een 

inspirerende stage of baan? Kijk dan op 

www.nelen-schuurmans.nl 

T o p a d v i s e u r s m e t e e n e i g e n m e n i n g 


Interview with 

Saket Pande and 

Markus Hrachowitz 

34 

Interview 

Since the first of April, the department has two new 

staff members: Saket Pande and Markus Hrachowitz. The 

Druppel send out Rostislav Peknice and Philip Stive to 

find out what they’re up to... 

QCan you tell us something general about yourself? 

Where are you from? What are you doing here? 

What is your background? Why are you in Delft? Or 

something else what you consider interesting for our 

readers? 

Markus Hrachowitz: I’m Markus, originally I’m from Vienna, 

Austria where I grew up and obtained my masters 

degree and also my Ph.D. in civil engineering. I worked 

there before I got a position as PostDoc at the University 

of British Colombia in Canada where I worked for 

three years and then we moved to Aberdeen in Scotland 

where we lived for another three years. During these 

years I developed my interest in hydrology (I started out 

as just a general general civil engineer) and developed 

general hydrologic models but also did lots of field experiments 

in Canada with bears and other wild animals. 

Now I’m here with my family and I hope I will develop 

my work and come up with new ideas for this group 

and make some nice contributions to hydrology. I am 

married and we’re living in the centre of Delft with our 

two year old daughter who likes singing, talking, running 

around the whole day and of course she keeps us very 

busy. 

“ 

” 

Saket Pande: I’m Saket I was born and raised in India. I lived 

in many cities in India because of frequent moving due to 

my father’s job. I have decent experience with many cities 

in the northern part of India. I did my bachelor between 

1996 and 2000 in civil engineering (minor in water and 

hydrology) at the Institute of Technology in Delhi. Then 

I moved to the United States of America where I did 

my Ph.D. in hydrology and water resources management 

between 2002 and 2005. My Ph.D. was about statistical 

theory in robust prediction and model building so it was 

more about system analysis and calibrating and building 

models. During my Ph.D. I also published in the Economics 

field. After finishing my Ph.D. I moved to Amsterdam 

where I joined a think-tank. This think-tank was financed 

by the Dutch ministry of external affairs. I was working 

with mathematical economists, resource economists and 

hydrologists for four and half years and during last year 

I attended several scientific conferences. I met people 

from the TU Delft water management department there 

and I was impressed by the work that is done here (especially 

Prof. Savenije’s and Prof. van de Giesen’s work). I 

started thinking that maybe I should focus more on one 

area (either hydrology or Economics) so I decided to 

apply at the water management department and luckily 

I was admitted as a researcher and lecturer in the water 

resources section. 

I have a family and recently I have a kid and I’m living in 

Amstelveen. 

QAnd you Markus, how did you became a part of 

the TU Delft? When did you start thinking about 

joining TU Delft? And can you talk a bit more about your 

work, project and research? 

M.H.: It was in December at a conference in San Francisco 

where I met Tom Bogaard and Professor Savenije. 

We had a nice chat and they told me they needed a 

Hydrology and water resources management 

are the only subfield where you can be 

very creative 

researcher and lecturer. Since my contract in Scotland 

was running out I decided to apply and finally I got this 

position. And what about my work? In the past I focused 

more on transit times of water in catchments and how 

long does it take for rainfall to end as runoff in the river. 

There was already extensive research on this topic so 

I tried to shift this knowledge to a wider framework 

and integrate it with real runoff modeling and pollutant 

transport. 


QAnd you, Saket, can you talk a bit more about your 

work? What part of hydrology have you decided 

to focus on? 

S.P.: Broadly, I worked in three disciplines: Hydrologic 

modeling, applied statistics and economics, and I like to 

be at the intersection of all these three. I am currently 

working on a couple of things like parsimonius modeling, 

modeling with only a few parameters. I am involved in 

research about complexity evaluation, complexity of hydrological 

models to quantify or give a number of different 

kinds of different models that we have and to give a 

number to what we think that hydrological model is. I try 

to give a number of complexity measurements from an 

abstract level to a more concrete and quantifiable level. 

The third field is economic modeling. I worked in mathematical 

economics and the research was about decision 

making, uncertainty, effect of uncertainty in hydrological 

modeling on decision making, or what are constraints 

of hydrology in the decision making process. Also decentralization 

of water allocation mechanism where in 

my focus so it was an intersection of mathematical, economical, 

hydrological modeling and applied statistics. 

QMaybe we missed that, did you study Economics, 

econometrics or something like that? 

S.P.: I got an opportunity to do my Ph.D. after my bachelor, 

in fact I didn’t do my master or to be more precise 

I didn’t have to do a master thesis but I had fulfill 

the course load of the master. After I had finished the 

course load of hydrology and water resources I was 

thinking what to do next. Because I still needed to do 

some courses I decide to take economic courses. It was 

very nice so to extend my Ph.D. I started publishing in 

mathematical economics. I dealt also with econometrics 

within the last three years via the think-tank I mentioned 

before. However, since it was a think-tank I kept contact 

with hydrology as well. So I was involved in these 

disciplines and to be more effective I decided to focus 

more on one of them and I choose hydrology and water 

resources management. 

M.H.: This is (in my opinion) the reason why we should 

cooperate and why we could make a good team because 

Saket is coming from the more theoretical side and I am 

from the practical side. 

S.P: I want to tell potential readers one more thing 

about why I chose hydrology and water resources management. 

Hydrology and water resources management 

are the only subfield where you can be very creative. In 

structural engineering you already have formulas, equations, 

etc. It is more deterministic. The field of hydrology 

is unique because it is more creative. 

M.H: In other words hydrology is a science which is not 

as well understood as other sciences yet. Hydrology and 

water resources management are a ‘young’ science compared 

to other sciences. 

QHow long are you supposed to stay here? 

M.H.: I have an initial two years contract and if 

everything is going quite well then I can get (hopefully) 

an extension. 

S.P.: Same for me. 

Q 

What do you expect for the coming two years? 

Do you have any specific goals? 

S.P.: There are many ideas that I would like to execute 

and then hopefully publish. So basically put the ideas together 

and start the “snowball effect”, getting more and 

more people excited about my ideas and inspire other 

people. 

M.H.: It’s difficult to say. There are always many ideas in 

research. Ideas are still being developed when other new 

ideas are already coming in… I have an ambitious goal 

to setting up the integrated watershed model in a way 

that it is able to take into account different fluxes in the 

watershed, at different scales, from slopes to very large 

catchments. 

35 

Interview 


Werken tussen wetenschap 

en praktijk 

Op 1 januari 2008 hebben WL | Delft Hydraulics, 

GeoDelft, de unit Bodem en Grondwater van TNO 

en delen van Rijkswaterstaat hun krachten in een 

onafhankelijk instituut voor deltatechnologie, 

Deltares gebundeld. 

Deltares biedt innovatieve oplossingen voor 

water- en ondergrondvraagstukken, die het leven 

in delta’s, kusten riviergebieden veilig, schoon en 

duurzaam maken. 

Door de koppeling met de kennis van WL | Delft 

Hydraulics op het gebied van watervraagstukken, 

die van GeoDelft op het gebied van dijken, wegen 

en ondergronds bouwen, die van TNO op het 

gebied van ondergrond en grondwater en die van 

RWS op het gebied van integraal waterbeheer, 

ruimtelijke ontwikkeling en bestuurlijke processen 

ontstaat een internationaal toonaangevend 

instituut op het gebied van deltatechnologie waar 

technologie én maatschappij centraal staan. 

Deltares is op zoek naar talentvolle mensen. Bij Deltares kom 

je terecht in een informele dynamische omgeving. Onze 

professionals doen praktijkgericht onderzoek en geven 

specialistisch advies in binnen- en buitenland aan 

opdrachtgevers die de allerlaatste kennisontwikkelingen 

toegepast willen zien. Ze adviseren de overheid en relaties bij 

het zoeken naar oplossingen die rekening houden met 

maatschappelijke ontwikkelingen. 

Projecten bevatten altijd nieuwe uitdagingen. Door kennis en 

ervaring te delen verleg je grenzen en breng je ideeën tot 

leven. Kennisontwikkeling doe je in-house of in samenwerking 

met collega’s uit het netwerk. 

Iedere medewerker - zowel in het primaire als in het 

secundaire proces - draagt bij aan onze innovatieve 

oplossingen. Je collega’s zijn divers: starters, bèta- en 

gamma-specialisten, economen, ecologen…. Nationale en 

internationale professionals zorgen voor een goede sfeer op 

de werkvloer en maken werken bij Deltares tot een wereldse 

ervaring. 

Bij Deltares kun je zelf je carrière uitstippelen. Of je nu 

projectleider wordt of expert op je vakgebied of een beetje van 

allebei, dat is je eigen keuze. Zoek je een functie bij een 

Nederlands topinstituut met een internationale reputatie? 

Kijk dan bij onze vacatures. Ook biedt Deltares jaarlijks plaats 

aan vele stagiairs. 

www.deltares.nl 

info@deltares.nl

Lustrum - Dispuut Watermanagement

Create successful ePaper yourself

Delete template?

Save as template?