**Exhibit 10a**

 

**INFORMATION ONMEMBERS OF THE SUPERVISORY BOARD, EXECUTIVE BOARD, STAFF DIRECTORS, AND OTHERMEMBERS OF THE SENIOR MANAGEMENT COMMITTEE**

 

**SUPERVISORY  BOARD**

 

**Professor Luck M. van Leeuwen Ph.D. (1933),Chairman**

Audit Committee, Selection andRemunera-tion Committee, Integrity Committee

Dutch nationality

Term 1991-2004

Current position: Professor atUniversity of Brabant

Previous positions:

Chairman Executive BoardAssurantieconcern Stad Rotterdam anno 1720 (1979-1994)

Member Netherlands Senate (1987-1999)

Non-executive board functions:

• Berenschot Holding N.V.

• Betonson Beheer N.V.

• International Advisory Board Fortis

• Colonnade N.V.

• Van Nieuwpoort Beheer N.V.

• Advisory Board Instituut voor Bedrijfskundigen (IBO)

• Arenthals Grant Thornton, Accountants and tax advisors

• Foundation Economic Cooperation Netherlands andEmerging Countries (SENO)

• Foundation Administration Office Shares Royal VolkerWessels Stevin N.V.

 

**Carlos Espinosa de Los Monteros (1944)**

Selection and RemunerationCommittee

Spanish nationality

Term 1998-2006

Current position: Chairman andCEO Mercedes Benz España S.A. and DaimlerChrysler España Holding

Previous positions:

Chairman IBERIA Airlines(1983-1985)

Non-executive board functions:

• Acciona S.A.

• Inditex S.A. (Zara)

• Gonzalez Byass S.A.

 

**André A. van derLouw (1933)**

Integrity Committee

Dutch nationality

Term 1986-2004

Previous positions:

Chairman Dutch NationalBroad-casting Corporation

Member Dutch Parliament(1970-1971) and (1982-1983)

Minister of Culture, Recreationand Social Work (1981-1982)

Mayor City of Rotterdam(1974-1981)

Non-executive board functions:

• Stadion Feijenoord

 

1

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**Jan Peelen M.Sc. (1940)**

Selection and RemunerationCommittee

Dutch nationality

Term 2000-2004

Previous positions:

Member Executive CommitteeUnilever

Several management positionswithin Unilever or subsidiary companies thereof

Non-executive board functions:

• Albron BV

• Friesland Coberco Dairy Foods

• Buhrmann NV

• VVAA Group BV

• Wageningen University and Research Centre

• National Regie-Orgaan Genomics

 

**Ross A. Webber Ph.D. (1934)**

Audit Committee

U.S. nationality

Term 1993-2006

Current position: EmeritusProfessor Wharton School of University of Pennsylvania.

Previous positions:

Vice President University ofPennsylvania (1981-1986)

Chairman Management DepartmentWharton School (1991-1995)

Non-executive Board functions:

• American Water Works Co., Inc.

• New Jersey-American Water Company

 

**Rijnhard W.F. van Tets (1947)**

Audit Committee

Dutch nationality

Term 2002-2006

Current position: Advisor tothe Executive Board of ABN AMRO Bank (2002)

Previous positions:

Banque Europeenne de Credit(Brussels) and Societe Generale (Paris) (1973-1975)

Sogon Swiss and First BostonCorporation (New York: 1975-1983)

Member of the Executive Boardof ABN AMRO Bank (1988-2002)

Non-executive Board functions:

• International Securities Market Association (Chairman)

• Foundation Holland Casino

• Reliant Energy Europe B.V.

• Wegener N.V. (Chairman)

• Foundation Company Pensionfund Building Industry(Chairman)

• Foundation Verenigd Bezit

• Foundation Kasteel de Haar

 

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**EXECUTIVE BOARD**

 

**Harrie L.J. Noy M.Eng. (1951), Chairman**

Dutch nationality

Current position: ChairmanExecutive Board since 2000

Previous positions:

Worked for ARCADIS in various(management) positions throughout his career, most recently as Member ExecutiveBoard

Non-executive board functions:

• Civieltechnisch Centrum Uitvoering Research en Regelgeving(CUR)

• Foundation Habiforum

• Executive Board VNO-NCW

• Advisory Board Euronext

• Dutch-German Chamber of Commerce

 

**Steven B. Blake M.Sc.Hydrology (1956)**

U.S. nationality

Current position: MemberExecutive Board since 1999

Previous positions:

Before joining ARCADIS, heldpositions at Spill & Tank Management and Engineering Enterprises

Non-executive board functions:

• Construction Industry Roundtable

• U.S. National Water Well Association

• Federal Relations Committee – CIRT

 

**C. Michiel Jaski M.Sc.Hydrology (1959)**

Dutch nationality

Current position: MemberExecutive Board since 2000

Previous positions:

Before joining ARCADIS, heldpositions at Shell and Philips

 

**Jan Zijlstra M.Eng. (1946)**

Dutch nationality

Current position: MemberExecutive Board since 1999

Previous positions:

Worked for ARCADIS in various(management) positions throughout his career, most recently as managingdirector ARCADIS Bouw/Infra

Non-executive board functions:

• ONRI – Organization for Consulting and EngineeringFirms

• Foundation Toekomstbeeld der Techniek

• Foundation P3&BI

• Railforum

• Foundation KNHM

 

**STAFF DIRECTORS**

 

**Hans van DordM.Eng. (1944)**

Dutch nationality

Director Corporate Developmentsince 2000

 

**Henk W.M.W. ten Cate RA (1953)**

Dutch nationality

Corporate Director Financesince 2001

 

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**Wim G.M. RupertM.Sc. (1945)**

Dutch nationality

Director Human Resources since1994

 

**Craig E. EisenM.Sc. (1951)**

U.S. nationality

Director Mergers andAcquisitions since 2002

 

**MEMBERS OF THE SENIOR MANAGEMENT COMMITTEE**

 

**Joe A. Hastey (1948)**

U.S. nationality

CEO ARCADIS G&M 1999

 

**Yann LeblaisM.Eng. (1952)**

French nationality

CEO ARCADIS FCI 2000

 

**Erhard Robold Dipl.-Ing.****(1956)**

German nationality

CEO ARCADIS Deutschland 1998

 

**Antonio Rocha (1941)**

Brazilian nationality

CEO ARCADIS Logos 1999

 

**Rein J. SirreM.Sc. (1942)**

Dutch nationality

Managing Director ARCADISNederland 2000

 

**Kees T.Slingerland M.Sc. (1960)**

Dutch nationality

Managing Director ARCADISNederland 2000

 

**Ludo Smans (1947)**

Belgian nationality

Managing Director ARCADISBelgium 1995

 

**Luis Valenzuela M.Sc. (1943)**

Chilean nationality

CEO ARCADIS Geotecnica 1989

 

**Luis Villarroya M.Sc. (1953)**

Spanish nationality

CEO Grupo EP 1999

 

**Simon P. Warmerdam M.Sc. (1950)**

Dutch nationality

Managing Director ARCADISEuroconsult 2000

 

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