Section 3: Past Inventory, Monitoring, and Research Activities in the Klamath Network Park Units

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Crater Lake National Park (CRLA)

FIGURE 3: Aquatic Resources and Watershed Boundaries of Crater Lake National Park, Oregon, NPS Klamath Network

General Summary of Past Activities: Crater Lake National Park has focused primarily on monitoring the water quality of Crater Lake. A long-term lake monitoring program has been active since 1983. Less comprehensive water quality inventories have been completed for ponds/lakes and streams located outside of the Mt. Mazama caldera. A Sun Creek bull trout restoration project and a survey of amphibians in the Whitehorse Ponds have also been initiated and/or completed.

Crater Lake National Park (Figure 3) was established by Presidential Proclamation on May 22, 1902. The 74,140 ha (182,304 ac) park is located at the southern end of the Cascade Mountains in south-central Oregon. The park is dominated by a large natural caldera lake formed after the eruption of Mt. Mazama, approximately 7700 years ago (Ramsey et al. 2003; accessed June 6, 2005 at http://geopubs.wr.usgs.gov/imap/i2790/i2790.pdf). The lake that is now in existence usually fluctuates seasonally between 1881 and 1882 m (573 – 574 ft) in surface elevation. However, fluctuations of up to five meters have been recorded (Redmond 1990). Crater Lake is the clearest and seventh deepest lake (592 m, 1942 ft) in the world, and has a strikingly deep blue color. Secchi disk clarity readings have been recorded as deep as 40 m (131 ft).

The water quality of Crater Lake and other freshwater resources in Crater Lake National Park has been an important management focus for over 100 years. Water quality monitoring of Crater Lake began in 1892 when Diller and Patton initiated the recording of Crater Lake water level (Larson 1987). Numerous inventory, monitoring, and research projects and programs have been completed or are being conducted within the caldera and focused on Crater Lake, or at sites located outside of the caldera.

Intra-Caldera Monitoring and Research

Monitoring and research activities from 1892-1984 that were designed to document the physical, chemical, and biological characteristics of Crater Lake are listed in Table 8. Most of these activities were of short duration and limited in scope (Larson 1987). A long-term Crater Lake water quality monitoring program, that is now 22 years old, was initiated in June 1983. Sampling has been most often conducted during July, August, and September, however, sampling also has been conducted in January, March, April, May, June, and October. Samples for the determination of lake water quality have been collected at predetermined depths from 0–550 m, and from intra-caldera springs (Larson 1987, 1990, 1996). Initially, up to 41 springs were sampled, but this number was reduced to five springs beginning in 1990. Water quality variables monitored as part of the longterm monitoring program (1983-present) are listed in Table 9. Introduced rainbow trout (Oncorhynchus mykiss) and kokanee salmon (Oncorhynchus nerka) have also been studied as part of the monitoring program. Detailed information concerning the long-term water quality monitoring program is available in Larson 1987, 1990, and 1996.

TABLE 8: Highlights of Crater Lake Monitoring and Research Activities, 1892-1984 (from Larson 1987)

TABLE 9: Crater Lake and Intracaldera Springs Water Quality Variables Monitored as Part of the Crater Lake Long-Term Monitoring Program (1983-Present)

Extra-Caldera Monitoring and Research

The first observations documenting aquatic resources outside of the Crater Lake caldera were published in 1929 and 1935 in the park’s Crater Lake Nature Notes publication. These articles identified and described, respectively, several mineral springs in the Annie Creek Canyon and six waterfalls that occurred at several locations in the park. Numerous articles in Crater Lake Nature Notes, survey reports, and articles published in peerreviewed scientific journals have, since the publication of those two early articles, documented the diverse types of aquatic resources present in the park. The first survey of park streams was completed in 1947 (Wallis 1948). This survey, focused primarily on trout distribution, included 41 stations on 19 streams where water temperature, average station width and depth, and velocity were measured and stream habitat was described. A more extensive survey of park streams and springs was conducted in 1967-1968 (Frank and Harris 1969). These surveys recorded 106 flow measurements for 46 streams and 21 springs, and collected 45 water samples from a subsample of 17 streams and 21 springs. Eight samples were analyzed for a complete suite of water quality variables, and 37 samples were analyzed for a subset of variables. In 1981–1985, approximately 10 springs were sampled for water chemistry analysis (Thompson et al. 1987). The Whitehorse Ponds, a complex of 15 ponds located on Whitehorse Bluff, were inventoried and sampled in 1992 and 1993 to document their physical, chemical, and biological characteristics (Salinas et al. 1994). Additional activities have included: (1) incidental observations and projects designed to survey and investigate the distributions and life history characteristics of amphibian species in Crater Lake and at freshwater sites outside of the caldera (e.g., Farner 1947, Farner and Kezer 1953, Kezer and Farner 1955, Bergmann 1997); and (2) a project to eradicate brook trout (Salvelinus fontinalis) from and restore native bull trout (Salvelinus confluentus) in Sun Creek. The bull trout restoration project was initiated in 1992 in response to the precipitous decline within the park of this genetically distinct Pacific Northwest population due to encroachment of introduced nonnative brook trout. Fish surveys of all Klamath River basin tributaries within the park have also been conducted.

Horizon Report

No report is presently available.

Resource Management Water Quality Concern

1) Long-term clarity of Crater Lake and health of the lake ecosystem

See Attachment I for CRLA water quality, fisheries and streams inventory, monitoring, and research study references.