Our city/county in Missouri has established a set of criteria for assessing the environmental sensitivity of watersheds. We have grouped the watersheds into categories 1, 2 and 3 (most sensitive to least sensitive) based on their environmental sensitivity. We propose to apply impervious surface limits of 10% in Category 1, 20% in Category 2 and 30% in Category 3. Increases could be earned by a developer through implementation of certain BMP's. I am looking for examples of similar regulations and the positive and negative impacts that have resulted.