Record rainfalls last year slowed recent progress on improving the health of the James River watershed, which covers about a quarter of Virginia’s land mass.

In a comprehensive assessment of its water quality, part of a biennial State of the James report, the James River Association gave the waterway an overall health grade of 60%, the Richmond Times-Dispatch reports. That figure, which the association deems equivalent to a grade of B-, is unchanged from 2017.

The report considers fish and wildlife populations, pollution levels, natural habitats and restoration efforts to arrive at its assessment.

“This is a positive sign for the resilience of the James, but it is a departure from the steady improvements that we have seen since we first issued the State of the James in 2007,” said William Street, CEO of the nonprofit river association.

Progress was slowed specifically by record rainfalls that led to an increase in dirty stormwater runoff and a decline in shad and oyster populations.