Susan Graas Ir.


Susan Graas is a senior lecturer in Water Resources Management at IHE Delft in the Integrated Water Systems and Governance department. She holds an MSc degree in Hydrology from the Delft University of Technology, faculty of Civil Engineering.

Susan's research activities focus on the areas of modelling water resources systems, water allocation, environmental flows and estuaries. She has a special interest in developing and modelling alternative reservoir operating policies to improve the ecosystem and analysing the trade-offs.

Her educational activities include teaching water allocation models, the fieldwork and groupwork of the Water Management programme and the new online course environmental flows. She is an experienced project leader and has been engaged in curriculum development and accreditation processes of Master programmes in the Integrated Water Management domain.

Before joining IHE Delft, she worked as a consultant in the Netherlands and Mozambique advising water boards, city councils and river basin organisations how to manage their water system. Here she specialised in the development and application of water resources models.

Recent and on-going research projects

Hydropower-to-environment water transfers in the Zambezi basin (Power2Flow)

This project analyzes the reallocation of water from the hydropower sector to the environment in the hydropower dominated Zambezi basin. The research addresses two different aspects 1) improving the understanding of the complex response of ecosystems to flow regime, focusing on flow and bio-geomorphological interactions and their links to the ecosystem response and 2) the development of policy instruments, including reservoir operating policies and cost-sharing mechanisms, which balance water uses for the environment and for energy generation. (DUPC funded 2009-2013)

Recent and on-going capacity building projects

Strengthening Ethiopian Universities in Integrated River Basin Management

Aimed to improve the education in the water domain in Ethiopia and to forge strong links between Ethiopian water sector organizations and universities. The project is a co-operation between eight Ethiopian universities and a consortium of knowledge providers from The Netherlands. IHE Delft had the lead in the project. (Nuffic funded 2009-2012) see


Bucx, T., W. van Driel, H. de Boer, S. Graas, V.T. Langenberg, M. Marchand and C. van de Guchte, 2014. Comparative assessment of the vulnerability and resilience of deltas - extended version with 14 deltas - synthesis report. Delta Alliance report number 7. Delta Alliance International, Delft-Wageningen, The Netherlands.

Fanaian, S., S. Graas, Y. Jiang and P. van der Zaag, 2015. An ecological economic assessment of flow regimes in a hydropower dominated river basin: The case of the Lower Zambezi river, Mozambique, Science of the Total Environment, 505, 464-473. doi:10.1016/j.scitotenv.2014.10.033 

Nyatsanza, F.F., S. Graas and P. van der Zaag, 2015. The impact of dynamic environmental flow releases on hydropower production in the Zambezi river basin, Journal of American Water Resources Association (JAWRA), 51 (4), 1029-1042. doi: 10.1111/jawr.12280

Graas, S., H.H.G. Savenije, 2008. Salt intrusion in the Pungue estuary, Mozambique: effect of sand banks as a natural temporary salt intrusion barrier, Hydrology and Earth System Sciences Discussions, 5, 2523-2542. doi:10.5194/hessd-5-2523-2008

Graas, S., A. Bos, C. Figueres and T. Adegoke, 2007. Partnerships in the Water and Sanitation Sector. Thematic Overview Paper 18, IRC International Water and Sanitation Centre. [peer-reviewed].

Horrevoets, A.C., H.H.G. Savenije, J.N. Schuurman and S. Graas, 2004. The influence of river discharge on tidal damping in alluvial estuaries, Journal of Hydrology, 294, 213-228. doi: 10.1016/j.jhydrol.2004.02.012