by Stephanie Smith
June 03, 2015
Several waterways on the Chesapeake Bay’s Eastern Shore saw improvements in water clarity over the past year, helping them earn higher grades in the Midshore Riverkeeper Conservancy’s fifth annual report card.
Of the sixteen rivers and streams tracked by the Midshore Riverkeeper Conservancy, grades for ten of the waterways improved from the previous year. This includes Tuckahoe Creek, a tributary of the Choptank and historically one of the area’s most polluted rivers, which was upgraded from a “D+” to a “C.” Increased water clarity and a rebound in underwater grass abundance helped the Choptank overall earn a “B-,” up from a “C” last year. Eastern Bay and the surrounding creeks showed modest improvement, all scoring “B” grades or higher.
Runoff from agriculture is the primary factor slowing the recovery of water quality in the area, according to the report. The Miles and Wye Rivers continue to struggle—earning “C” grades overall—due in part to increases in nitrogen pollution and low dissolved oxygen levels. Excess nutrients can fuel the growth of harmful algae blooms, blocking sunlight and creating low-oxygen “dead zones” that suffocate aquatic life.
Grades are based on data from more than 100 sampling sites, where volunteers test for water clarity, dissolved oxygen, nutrients and chloropyll a. The Midshore Riverkeeper Conservancy also tracks water temperature, pH, salinity and bacteria levels.
For more information on nutrient and sediment loads in the Bay’s major rivers— including the Choptank—see the Bay Program's latest pollution load indicators.