Arcadis NV — M&A Activity 2011

Nov 1, 2011

PRESS RELEASE

ARCADIS NV Gustav Mahlerplein 97-103 P.O. Box 7895 1008 AB Amsterdam The Netherlands Tel +31 20 2011 011 www.arcadis.com

EC HARRIS PARTNERS AGREE TO MERGE WITH ARCADIS

November 1, 2011 – ARCADIS (EURONEXT: ARCAD), the international design, consulting, engineering and management services company, today announced that the partners of EC Harris LLP, the international built asset consultancy headquartered in London, U.K., have voted essentially 100% in favor of the merger with ARCADIS. The formal closing of the transaction is expected to take place on November 4 or 7, 2011. This will include the transfer of 3.0 million ARCADIS shares and an undisclosed cash amount to the partners of EC Harris as part of the merger agreement. EC Harris is a provider of high-value consulting and management services for the realization and operation of buildings, manufacturing and processing plants and infrastructure facilities. ARCADIS and EC Harris first announced the merger on October 17, 2011.

Through this merger, ARCADIS grows to almost 19,000 professionals and € 2.3 billion revenues. ARCADIS and EC Harris together now hold a top five global position in strategic advisory and project delivery services for "Built Assets". The combined company has close to 6,000 staff in this segment, with leadership positions in Europe, the U.S. and Brazil. The merger also serves to strengthen ARCADIS' presence in Asia to a total of 700 people and in the Middle East to 400 people. Furthermore, ARCADIS now has well over 2,000 people in the U.K., bringing us in the top ten in this major market and allowing us to expand our relationships with multinational clients both inside and outside the U.K.

ARCADIS CEO Harrie Noy about the merger: "I am extremely pleased that the partners of EC Harris have acknowledged the great strategic benefits of this merger. I truly believe that the leadership position our combined firms have in project management and related consultancy services, offers genuine opportunities for expansion in key emerging markets, while at the same time giving us a strong base in the well-developed U.K. consultancy market, a position we have aspired to achieve for many years. We welcome the strength of the EC Harris brand and the leadership they bring to ARCADIS and are excited about the synergy opportunities."

Philip Youell, Chief Executive of EC Harris said: "I am delighted that our Partners have ratified the proposals and we can now proceed to merge with ARCADIS. Since announcing our plans we have had an overwhelmingly positive reaction from our partners, people, clients and the market. ARCADIS and EC Harris are a natural fit and there is genuine excitement about the opportunities that the merger presents. We will now begin the process of integrating our two firms, with EC Harris retaining its brand within the wider group. I am looking forward to working with our new colleagues at ARCADIS to meet our clients' needs."

For more information please contact Joost Slooten at +31 (0) 20 2011083, or outside office hours at +31 (0) 6 27061880 or joost.slooten@arcadis.com

For more information about EC Harris, contact Andy Rowlands at +44 (0) 20 7833 6662 or +44 (0) 7810 850 476 or andy.rowlands@echarris.com

About ARCADIS:

ARCADIS is an international company providing consultancy, design, engineering and management services in infrastructure, water, environment and buildings. We enhance mobility, sustainability and quality of life by creating balance in the built and natural environment. ARCADIS develops, designs, implements, maintains and operates projects for companies and governments. With 16,000 people and EUR 2.0 billion in revenues, the company has an extensive international network supported by strong local market positions. ARCADIS supports UN-HABITAT with knowledge and expertise to improve the quality of life in rapidly growing cities around the world. Please visit: www.arcadis.com

About EC Harris:

EC Harris is an international Built Asset Consultancy, advising clients in the planning and execution of strategies that deliver the best results from money spent on their built assets. The firm has 48 offices in 28 countries employing over 2,600 people worldwide. EC Harris revenue in 2010/11 was over £250 million. For further information visit www.echarris.com