This paper reports on a Catchment Modelling Framework (CMF) designed to support an Australian pilot of an auction for multiple environmental outcomes - EcoTender. The CMF is used to estimate multiple environmental outcomes including carbon, terrestrial biodiversity, aquatic function (water quality and quantity) and saline land area. This information was previously unavailable for application to environmental markets. This is the first time a market-based policy has been fully integrated from desk to field with a Catchment Modelling Framework for the purchase of multiple outcomes. This framework solves the unknown information problem of linking paddock scale landuse and management to catchment-scale environmental outcomes. The framework provides the Victorian government with a replicable transparent evidence-based approach to the procurement of environment outcomes.