Streamflow Conditions in New England, Spring 2021

The animation demonstrates this variability.

Sources/Usage: Public Domain. View Media Details

In early March, conditions were considered to be mostly normal (based on a scale determined by USGS WaterWatch), but by mid-March, flows in southern New England were much below normal based on historical data for that time of year. On average, flows in mid-March tend to be higher than previous months because of snowmelt and spring rain. Above normal flows were observed in late March, but by mid-April conditions returned to below normal and to much below normal in widespread areas of Connecticut, Massachusetts, Rhode Island, Vermont, New Hampshire, and coastal Maine. Short rain events and periods of snowmelt brought intermittent relief from the below normal conditions through late April, but by mid-May, most of New England was again seeing much below normal conditions. Many sites recorded their lowest flows ever for those specific days.

The chart shows the variable conditions from April 1 to mid-June for 160 stations in New England with 30 (or more) years of record. The colors represent the same categories of normal from USGS WaterWatch. The scale on the left side of the chart indicates the percentage of the 160 stations within each of those categories. Conditions were dry in April, with nearly 85 percent of these stations in some category of below normal streamflow. In late May, the percentage of stations in the low, much below normal, and below normal conditions increased further. The chart also highlights the short-term relief from rain and snowmelt and the return of dry conditions when rainfall is inconsistent.