Interdisciplinary research is capable of investigating questions that no single or independent collection of disciplines can address. This  interdisciplinary approach was used to investigate why nonpoint source pollution to a lake had not changed even though the often cited social drivers of this situation had changed significantly. The concept of disproportionality was adapted to examine social and biophysical interactions at different spatial and temporal scales to address this situation. Rather than using social and biophysical variable as contextual or additive relative to each other, we examined their interactive or multiplicative effects at coarse and fine spatial and temporal scales. Limited occurrence of inappropriate behaviors in vulnerable biophysical settings resulted in disproportionate environmental impacts. The concept of disproportionality implies that the environmental meaning placed on any social behavior requires accounting for where and when it occurs in a biophysical setting, and that a few outliers can determine system performance and outcomes.