USDA Forest Service

Pacific Southwest Research Station
Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
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Research Topics

Recreation: Behaviors and Conflict

Boating Capacity at Shasta and Trinity Lakes

Dr. Alan Graefe, Penn State University, and Jim Absher have completed a carrying capacity report for the Shasta-Trinity National Forest. Concerns over crowding and user conflicts led to a study of boating capacity at Shasta and Trinity Lakes in northern California. Objectives of the study included: developing a profile of recreation users; measuring recreation use patterns at the lakes; measuring visitor expectations, perceptions of existing conditions, and satisfaction; and examining visitor opinions about lake management.

The study provides a comprehensive model for looking at recreational carrying capacity. In this case, boating use patterns were measured through aerial and ground counts. Visitor data were collected through a series of on-site and mail surveys of key user groups. This multiple measurement and approach facilitated a comprehensive evaluation of the relationships between use levels and the quality of visitor experiences.

During the 2002 boating season 789 on-site visitor interviews were completed. A follow-up mail survey (254 respondents) and information from three key user groups (1,236 houseboat, moorage, and rental customers) added to the database.

Results showed striking differences in use levels and visitor perceptions between Shasta and Trinity Lakes. Shasta Lake receives heavier boating use, accompanied by higher levels of perceived crowding and related impacts. A geographic information system (GIS) was used to analyze lake use patterns and identify favorite and most used locations, along with areas that were avoided or considered unsafe.

Integration of the spatial and attitudinal data revealed the reasons underlying site choices and responses to varying conditions. Avoided locations were classified into social (e.g. crowding) and environmental reasons (e.g. windy conditions or debris). To assist management, an analysis of boater travel routes by access points showed the zone of influence of each developed area.

Perceived crowding was slightly higher on Shasta Lake and reached its peak on both lakes over the July 4th weekend. Crowding levels and related impacts such as user conflicts and displacement were relatively consistent over the rest of the boating season. The majority of boaters encountered use levels that they expected and accepted. Satisfaction levels were high among all user groups and were not strongly tied to use levels. Lake users reported various ways in which they have modified their boating participation due to crowded conditions such as avoiding holiday weekends, coming earlier or later in the year, or going to different locations on the lake.

The most popular management alternatives among all user groups included aggressive law enforcement, establishing "off-limits" zones for sensitive areas, and restricting personal watercraft (PWC) use to designated areas. Responses to some options varied markedly between user groups. For example, boat ramp users were far more likely than moorage houseboat users to favor development of more public access points. No user group favored limiting the number of boats on the water. All of them, however, also tended to oppose increasing the allocation of private or commercial houseboat permits on either lake.

Overall, study results suggest that boating on Shasta and Trinity Lakes has not reached problematic levels but may be near capacity at this time. The results have helped managers on the Shasta-Trinity National Forest to revise their lake management plan. Proposed actions will emphasize small incremental changes to protect the quality of the visitor experience while allowing more lake access for the public.

Research conducted by:
Last Modified: Aug 29, 2016 11:05:14 AM