It has been convincingly argued that computer simulation modeling
differs from traditional science. If we understand simulation modeling
as a new way of doing science, the manner in which scientists learn
about the world through models must also be considered differently. This
article examines how researchers learn about environmental processes
through computer simulation modeling. Suggesting a conceptual framework
anchored in a performative philosophical approach, we examine two
modeling projects undertaken by research teams in England, both aiming
to inform flood risk management. One of the modeling teams operated in
the research wing of a consultancy firm, the other were university
scientists taking part in an interdisciplinary project experimenting
with public engagement. We found that in the first context the use of
standardized software was critical to the process of improvisation, the
obstacles emerging in the process concerned data and were resolved
through exploiting affordances for generating, organizing, and combining
scientific information in new ways. In the second context, an
environmental competency group, obstacles were related to the computer
program and affordances emerged in the combination of experience-based
knowledge with the scientists' skill enabling a reconfiguration of the
mathematical structure of the model, allowing the group to learn about
local flooding.