The art of cleaning dams

13 March 2015

Artistic drawings of gargantuan portions have been gracing dam walls across Germany, Japan and Korea. Suzanne Pritchard takes a closer look at one of the most creative developments the industry has witnessed in recent years.

We all know about the multipurpose nature of dam projects but I bet there is one function you've overlooked: using dams as a projection screen for monumental works of art. Yet an innovative German collaboration, between cleaning equipment manufacturer Karcher and artist Klaus Dauven, has won artistic acclaim for the dams industry on a scale never witnessed before.

Utilising its cleaning expertise, Karcher has been engaged in the preservation of historic monuments and buildings on an honorary basis for more than 30 years. The company believes that its international cleaning projects, from the Statute of Christ in Rio de Janeiro to the Brandenburg Gate in Berlin, provide true evidence of how its equipment can perform. Having helped to preserve more than 100 historic monuments as part of its cultural sponsorship programme, Karcher has provided equipment free of charge along with the practical assistance of its cleaning specialists.

"Our co-operation with the artist Klaus Dauven started in 2005," says David Wickel-Bajak, Manager of Corporate Communications at Karcher. "We were talking about another dam project that was taking place at the same time. For this project our input was to clean the dam with high pressure washers as the artist Pierre Mettraux needed a clean wall before he could start painting. Then Klaus came up with the idea of doing it the other way round."

Dauven invented the process of drawing by cleaning (known as reverse graffiti) in 1997. He first worked with a vacuum cleaner on a large sheet of paper covered with charcoal, so that when vacuumed the nozzle left bright traces. Two years later he progressed to working on larger canvases and used a wire brush on a concrete wall outside of his art studio. He was literally turning cleaning into an art form. Then in 2003 he had the ingenious idea of utilising a high pressure cleaner as a drawing utensil. He produced numerous temporary drawings on underpasses and bridge supports in public spaces but did not change these permanently in the way that graffiti artists usually do. Gradually his work became more intricate and more ambitious in scale.

Realising that gravity dam walls could offer the largest projection surfaces, Dauven partnered up with cleaning equipment manufacturer Karcher. The first project undertaken to showcase this remarkable combination of high pressure cleaning and art, materialised at Oleftal Valley dam in Germany in 2007.

After studying the soiled surfaces of the dam carefully, Dauven used the widely variable pressure and water flow of a high pressure jet, not to preserve art, but to create it. Cut outs and contrasts and the juxtaposition of cleaned and untreated surface areas gave rise to monumental and intricate drawings.


Oleftal Dam in Eifel National Park is operated by the Eifel-Rur water utility and was built between 1955-9. One of just two columnar buttress dams in Germany, it comprises a chain of sixteen hollow columns linked by sealing elements. It supplies power and drinking water to the district of Euskirchen and the Aachen metropolitan area.

Jets of water were used to etch out animal motifs from the build-up of fouling on the valley side of the 282m long and 59m high dam. Native forest animals, birds and fish were drawn on untreated surrounding areas of the dam wall to form the appropriately named "Wild-Wechsel" (Game Pass).

To enable Dauven's design to be transferred to the dam wall, Munich-based surveyors Geosys digitised the image and projected it on to the wall using laser technology. Cleaning was carried out using a Karcher SPP 60 submersible pressure pump which supplied water to three Karcher HD 10/25 cold water pressure washers placed on top of the wall. With the support of GSAR mbH, a company specialising in rope access technology, climbing ropes and a travelling platform were used to access all parts of the wall to remove the soiling, which consisted almost entirely of organic matter. The end result was considered to be the world's largest drawing with a surface area of more than 8000m2.

"The general public saw how creatively our pressure washers could be deployed," said Hartmut Jenner, CEO and Chairman of the Management Board at Karcher. "The animal motif that Dauven created here caused quite a stir, especially across state frontiers."

Sensational project

Following on from the success of this project, Karcher and Dauven partnered up again in 2008 to mark the 20th anniversary of Karcher's Japanese subsidiary. This time five delicate blossoms were drawn on the Matsudagawa dam near Ashikaga City in Japan.
Surveyors digitised the image before cleaning commenced and used laser technology to transfer it on to the 228m long and 56m high dam wall. To ensure the accurate transfer of intricate features such as the stamens of the flowers, more than 750 points were marked with modelling clay by industrial climbers. The pressure washers were used to join these up on a 'painting by numbers' principle and thus the drawing was in the exact proportions as Dauven had envisaged.

Four Karcher HD 1050B cold water pressure washers were used, which are capable of pumping up to 930 litres of water per hour and can reach operating pressures of up to 230 bar. As the Matsudagawa dam has a comparatively small angle of incline it had to be rinsed twice to ensure that loosened dirt was removed completely.

The dirt on the dam consisted mainly of moss, algae and lichen that could be cleaned off without using chemicals, in compliance with the ecological requirements of this water protection area. Fan-jet nozzles were used to produce an even spray pattern which was ideal for drawing and highlighting the contrast between cleaned and dirty parts of the dam as clearly as possible.

"This sensational project was an extraordinary challenge," says Hartmut Jenner from Karcher. "Our German-Japanese team mastered it most professionally."

Eibenstock dam

The next dam to become a canvas for Dauven was the 308m long and 57m high Eibenstock dam in Germany. Built in 1982, it provides flood protection and hydropower, and is the largest drinking water reservoir in Saxony with a capacity of 64Mm3.
In August 2012 two river trout, entitled Fisch-Reich, were depicted on the dam. More than 1000 measurement points were used and marked with modelling clay to transform the artist's A3 landscape format onto the structure. Dauven worked from a façade lift and was supported by industrial climbers who abseiled from the top of the dam. Three HP 13/18-4S cold water high pressure cleaners were used; capable of pumping up to 1300 litres of water an hour up to a pressure of 200 bar.

Sympathetic art

Chungju dam is located 100km southeast of Seoul and is South Korea's biggest dam. Standing at 98m high, 447m long and with a reservoir capacity of 2.7Bm3, it has been providing water supply for the region since 1985. Chungju also generates power and provides important flood protection. In October 2012 the dam carried out another function - a giant canvas for Dauven's artistic talent.

A tiger called Horang-ee was drawn onto the structure utilising 1300 measurement points. The cleaning work was carried out by HD 10/25-4 S high pressure cleaners. Different challenges had to be overcome at this dam. A large number of recessed installations in the wall made it a comparatively irregular work surface, while differing levels of dirt meant that the art work had to be positioned precisely.

"Works of art using high pressure cleaners are transitory," says Hartmut Jenner. "Unlike graffiti, these drawings fade away of their own violation. After only a few years it is no longer possible to discern the difference between the areas that were cleaned and those left dirty. This sympathetic art form does not impose in any way on the host structure," he added.

Costs for the dam art varies from five to six digit Euros. Each project took about two weeks to complete with six to eight people working on them. Depending on the climate and the direction the dam wall faces, the art work can last about five years in Germany and up to three years in Japan.

"The reaction in Japan and Korea was even better than in Germany," Dauven says upon reflection. "Newspapers and TV stations showed the dam drawings and people were very interested in them. Some of the walls even became tourist attractions. It helped to change the dams' public image."

Indeed Dauven believes that to elevate a dam into a work of art, distracting from its actual function for a while, is an interesting possibility. It offers an amazing perspective in terms of artistic medium, local history and the use of public spaces. Dams are seen as one of the ultimate structures which harness natural power. Dauven believes that his work acts as a reminder of the humbling scale of human endeavours and that, however impressive these achievements are, everything will eventually return to nature.

"Over recent decades," Hartmut Jenner says, "Karcher has made a name for itself by executing cleaning projects on historic monuments and buildings of note the world over. By working in co-operation with Klaus Dauven we have had the opportunity to be involved in a cultural heritage programme of quite a different type. This sympathetic art form is fully in keeping with our cordial and highly successful long term co-operation with Dauven. I look forward with eager anticipation to our on-going exchange of ideas and future joint projects."

"This is a really nice project we've been running with Klaus," David Wickel-Bajak added. "It is a very personal way to support cultural heritage. And we are always looking for new projects."

Klaus Dauven can be contacted at

Pressure pumps Karcher used its range of submersible pressure pumps and high pressure cleaners on these projects.
Eibenstock 2 Eibenstock Dam in Saxony, South East Germany. Pressure washers were used to carve out an image of two native trout from a layer of fouling that was up to 30 years old.
Climbers Industrial climbers abseil from the top of the dam to support Dauven’s work
Partners The partnership between Karcher and Klaus Dauven started with the Oleftal dam in 2007 when this animal motif created quite a stir.
Digitised The artist’s original image was digitised and projected onto the dam wall using laser technology.
High pressure Dauven worked using high pressure cleaners to remove dirt and create art.
Tiger South Korea’s biggest dam, Ghungju, showcased this impressive tiger in 2012.
Eibenstock Eibenstock Dam in Saxony, South East Germany. Pressure washers were used to carve out an image of two native trout from a layer of fouling that was up to 30 years old.
Complete It took about two weeks to complete each work of dam art using reverse graffiti.
Blossoms Five delicate blossoms were drawn on Japan’s Matsudagawa dam in 2008.
Tiger 2 South Korea’s biggest dam, Ghungju, showcased this impressive tiger in 2012.
A3 The artist’s A3 landscape format was transformed onto the dam wall with the use of laser technology.

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