The index will draw on publicly available data regarding physical scarcity and water quality and overlay important factors including the regulatory regime and social and reputational issues that have not previously been incorporated into water risk measurement. The index measures four areas including: access to improved drinking water and sanitation, the availability of renewable water and the reliance on external supplies, the relationship between available water and supply demands, and the water dependency of each country’s economy. To date many modelling studies have simulated the impact of mitigation strategies on annual pollutant loss as opposed to pressures during seasonal ecological windows (Collins and McGonigle, 2008). Further development of these models to improve the targeting of policies, however, needs to pinpoint specific ecological windows of opportunity (e.g. salmon spawning season) as opposed to annual loadings and their abatement (Collins and McGonigle, 2008). Environmental Science and Policy, Vol. 115A, HELCOM, Helsinki, Finland.