Crater Lake Research

Limnology

The park's limnological monitoring program ensures the health and preservation of Crater Lake. Through monitoring and research efforts, the program serves as a platform to develop and communicate a better understanding of biological, physical, geochemical, and climatological processes that affect the lake.

Limnological studies of Crater Lake occurred as early as 1886. Studies conducted from 1978 to 1981 suggested that water quality might have deteriorated compared to observations made years earlier. A review of existing lake data by the NPS and a panel of limnologists in 1982 concluded that the existing data was insufficient to determine if the lake had actually changed and recommended monitoring to document the basic characteristics of the lake. In the fall of 1982, Congress passed Public Law 97-250 that directed the Secretary of the Interior to conduct a 10-year study on Crater Lake to examine the lake for possible deterioration of water quality.

Long-term Lake Monitoring Program

The long-term limnological monitoring program (LTLMP) at Crater Lake began in 1983 and included four major goals:

1. Develop a reliable database for the lake to be used for comparisons of future conditions.
2. Develop a better understanding of physical, chemical, and biological processes occurring in the lake.
3. Investigate the possibility of short- and long-term changes in the lake.
4. And if changes are found, and human-caused (e.g., pollution), recommend mitigation techniques.

The results from the mandated 10-year program concluded that the lake had not declined in water quality or clarity, within the limits of the methods used and the period of time studied. Additional funding has permitted the LTLMP to continue and expand the scope of monitoring efforts. To date, the LTLMP has spanned 37 years (1983-2020) and has amassed more than 25 datasets that help us understand and preserve the unique system of Crater Lake.

State of the Lake Report

The State of the Lake Report presents updated data related to the long-term health of the lake, and a current and evolving understanding of how the lake functions. Each year the report's content changes to reflect the current lake status. It summarizes recent projects that focus on important, emerging issues. It may include overall trend-analyses, which are updated on approximately five-year intervals. This report is primarily intended to inform park management and the general public about Crater Lake. It is not an exhaustive review of all pertinent limnological literature but does present examples from other lakes and research studies where appropriate.

State of the Lake Report: 2020
State of the Lake Report: 2018