The non-linear responses of environmental systems to changes imposed upon them is well known to scientists. Environmental managers rarely act accordingly, however, because of communication problems, a lack of imagination and various other constraints. Therefore, we illustrate such non-linear responses to demonstrate that gains in efficiency (benefit per money spent) can be made by integrating these characteristics into decision making. Identifying three measures that are currently the focus of large freshwater management budgets (waste-water treatment, riparian buffer strips and discharge allocations to regulated rivers), we relate the costs of these measures to the environmental improvements achievable in running waters. For each of these measures, the environmental improvement achieved per currency unit significantly decreases with an increase in total money spent. Traditional environmental management ignores this system behaviour because it invests important parts of budgest in a particular measur before focusing on the next amon other measures. We therefore advocate alternating investments in that measure which achieves the greatest envrionmental improvement in the next possible investment step. Compared with traditional management, this alternating decision-making strategy will achieve greater environmental improvements for a given total budget.