The US EPA Lake Erie indicators monitoring program 1983 – 2002: Trends in phosphorus, silica and chlorophyll a in the central basin
April 5, 2005
During the past 20 years, Lake Erie has exhibited a series of complex chemical changes resulting from changing anthropogenic influences and introductions of exotic species. Since 1990, some apparent trends in nutrient concentrations have been inconsistent with the predictions of models originally used to guide Lake Erie water quality management. We performed time trend analysis on total phosphorus (TP), chlorophyll a Chl a), and dissolved reactive silica (DRS) measurements collected during spring and summer in the central basin of Lake Erie between 1983 and 2001.
April 5, 2005
The Rotorua district in New Zealand contains 12 nationally important lakes. Environment Bay of Plenty (EBOP), which has the responsibility of managing the quality of these lakes, set a routine monitoring program for these lakes and adopted the method of Burns et al. (1999, 2000) to analyse the data and calculate a numeric Trophic Level Index (TLI) value for each. In 1994, the district community indicated a goal to maintain the present condition for most of the lakes and to improve the remainder. As a result, nu- meric baseline TLI values were written into the Proposed Regional Water and Land Plan as the Rotorua District lake-water quality objectives.