Indicators

Core Indicator	Metrics	Status	Trends
Estuarine Waters
Hypoxia	Dissolved oxygen levels	Interannual variability due to weather and tides; follows N/S gradient; most severe in Providence-Seekonk River and Greenwich Bay; documented for Upper Bay and some embayments.	Ten years of data in Upper Bay and embayments; severity dependant on weather, tides and river flow.
Chlorophyll	Chlorophyll and macroalgae	Used as indicator of primary productivity. Highest levels in upper bay; also high in Greenwich Bay/Lower Taunton River.	Annual bloom has shifted from winter/spring to summer in mid/lower Bay.
Beach Closures	Enterococci	Dependent on rainfall levels and local stormwater impacts.	Closures tend to follow rain events; closures affected by local conditions and stormwater runoff.
Shellfish Restrictions & Closures	Fecal coliform bacteria	Reflects N/S gradient and local stormwater impacts; affected by weather/rainfall; operational changes allow some conditional openings.	Closure rates predicted to decrease as CSO abatement projects come online.
Fresh Waters
Fresh Waters Impaired by Bacteria	Enterococci and fecal coliform bacteria	Not all waters assessed. Of those assessed, 40% RI river miles and 52% MA river miles impaired; 4% RI lake acres and 0.2% MA lake acres impaired.	Dependent on rainfall and wildlife populations.
Fresh Waters Impaired by Dissolved Oxygen	Dissolved oxygen levels	Not all waters assessed. Of those assessed, 5% RI river miles and 57% MA river miles impaired; 10% RI lake acres and 5% MA lake acres impaired.	Affected by nonpoint source inputs and, on major rivers, by point sources; varies by location; temperature; physical conditions.
Fresh Waters Impaired by Nutrients	Nirogen and phosphorus	Not all waters assessed. Of those assessed, 4% RI river miles and 25% MA river miles impaired; 15% RI lake acres and 6% MA lake acres impaired. Neither state has numeric standards for nutrients in rivers.	Affected by nonpoint source inputs; varies by location; temperature; physical conditions.
Chloride in Lakes	Chloride (RI lakes data since 1988; not available for MA lakes)	No RI lakes violate criteria.	Concentrations in RI lakes increasing since 1993.
Low Flow	Water levels; changes in riverine fish communities	Several RI rivers exhibit extreme low flow conditions; some impacts to fish populations documented; affected by user demand/drought conditions; MA fisheries staff observed no flow conditions in sime Dighton brooks.	Existing data limited for many waters; large river stream gauge data show summer flow declines over time; Aug. flows in one Blackstone river basin declined 55% since 1979.