Recreational Use: levels and trends

Our recreational use statistics come directly from the National Park Service's "Monthly Public Use" (MPU) reports. We then performed "regressions" to analyze the "best fit" lines -- that is, to see if there is a trend over the years.

The MPU reports count various recreational activities in terms of days of use. We collated by month for the period 1989 through 1993 and summarize the data in Appendix C-2. We collated the MPU monthly count for fishing days, hunting days, hiking days, and canoe days. The "boating days" is a combination of canoe days, raft days, and johnboat days; we refer to those collectively in this report as "canoe days" for simplicity. We also collate by month the total number of overnight stays and the total number of recreational visits. The total visit count is not a sum of all the other days, because it counts visitors instead of counting days, and also counts mixed-purpose visits and so on. We have also collated the MPU data for visitor hours at the NPS visitor centers, and monthly precipitation, but we do not analyze those statistics further.

We use the "recreational visit" count as our basic measurement of recreational use of the BNR. Table 4.1 and Table 4.2 summarize the recreational visit totals graphically, and chapter 4.1 discusses the trends. Chapter 4.3 analyzes the correlation between the monthly recreational visits and various pollution levels. We use "canoe days" and "fishing days" as our measurement of water-based recreational activity. These data are also summarized in Table 4.3 and analyzed in chapter 4.3. We use "overnight stays," "hunting days," and "hiking days" as our measurement of land-based recreational activities. Pollution levels do not apply to these, because the pollutants under study are water-based, but these data are also summarized in Table 4.3 and discussed in chapter 4.1.

For our regression lines, all trends use eleven dummy variables for months (omitting January, the lowest visitation month, to avoid perfect multi-collinearity). Hence the trend lines indicate the yearly increase independent of the monthly use pattern. We omit the month dummy coefficients from all of our reported results.

Recreational Visitation, 1989 to 1992 Figure C-1

Annual Visitation = 924,000+ (Year - 1988) x 45,500 R2 = 95.4%

(-1.79) (1.86) Conf.= 93%

Overnight Stays, 1989 to 1992 Figure C-2

Annual overnights = 72,700+ (Year - 1988) x 18,900 R2 = 95.2%

(-4.81) (4.82) Conf. >99%

Boating Days, 1989 to 1992 Figure C-3

Annual boating = 105,600 - (Year - 1988) x 5,450 R2 = 89%

(1.02) (-1.015) Conf.= 69%

Fishing Days, 1989 to 1992 Figure C-4

Annual fishing = 23,200 - (Year - 1988) x 1,190 R2 = 79%

(1.18) (-1.15) Conf.= 75%

Hunting Days, 1989 to 1992 Figure C-5

Annual hunting = 13,200 - (Year - 1988) x 1,280 R2 = 93%

(2.40) (-2.29) Conf.= 97%

Hiking Days, 1989 to 1992 Figure C-6

Annual hiking = 17,600+ (Year - 1988) x 4,440 R2 = 60%

(-1.78) (1.82) Conf.= 92%