How are good, fair and poor defined in the report?
Thresholds for good, fair and poor (or high, moderate, low) were defined in two ways for the NLA report, depending on the specific indicator. The first type of threshold used in the NLA is the fixed threshold. The values for indicators such as dissolved oxygen are based on longstanding, accepted values from the literature. They are well-established and frequently used. For example, all lakes were compared to the following dissolved oxygen thresholds: ≥5 mg/L (high), >3 to <5 mg/L (moderate) and ≤3 mg/L (low). The second type of threshold is based on reference condition. In order to assess the condition of the nation’s lakes, findings for a number of indicators including biological condition, nutrients, habitat condition, etc were compared to conditions in a suite of reference lakes. For these indicators, a lake was classified as either "good", "fair" or "poor" condition relative to conditions found in reference lakes. Good denotes an indicator value similar to reference condition while
