From which years did the Phase I regulations occur?

The Phase I regulations, specifically relating to the National Pollutant Discharge Elimination System (NPDES) for stormwater discharges, were established through a set of rules that began to take shape in the late 1980s. The Phase I rules, which targeted discharges from large construction sites and certain industrial activities, were developed under the Clean Water Act.

The correct range of years, 1987 to 1992, reflects the period when these regulations were drafted and implemented. During this time, the U.S. Environmental Protection Agency (EPA) finalized the Phase I stormwater regulations in 1990, and they formally took effect, marking a significant step in managing water pollution from urban runoff and construction activities.

This timeline is critical because it provides context for how regulatory frameworks were formed to address specific environmental concerns related to stormwater discharges, emphasizing the need for better management practices to protect water quality.