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,is on flow , t aled to Z tive judg- 'd by Hull for paired -. ler scenic I; Buhyoff rovide an ~ two ob- ere multi- similar in lTe caUed ry ~eriments es at any n vegeta- weather, within all as scenic reases as : from the tbe eight : range in lei, but a evident. hat more which is Ie paired- ; showing ,m USGS by visual listed in :'e scenes or of the nnel, and indepen- leir judg- for these of 0.9t. : the four ror the :D, Table he scene :t lowest accuracy Ie. essed by ::present- Because ,eauty to terms in ncluded, luced for jed both esis [hat low and imum at BROWN AJJ gAQIa.~~NDSCAPE AESTHETICS OF RIPARIAN ENVIRONMENTS TABLE 2. Variables Name De scription Dependent SBE scenic beauty estimate (by-stimulus version [Brown el ai" 1990aJ) Independent- FLOW SOIL flow in cubic feet per second (cfs) percent of scene showing sailor sand (brownish color) percent of scene in deciduous or coniferous arboreal vegetation percent of scene in rock outside of river channel percent of scene in sky percent of scene in water percent of scene showing exposed nver bed (sand and rocks) five. point rating of distance to farthest nonsky feature in scene (I = near. 5 = distant) five-point rating of water sound (I = bearly perceptible, 5 = loud) five-point rating of wind noise picked up in audio (I = none, 5 = loud) five-point rating of width of stream channel (I = narrow. 5 = wide) five-point rating of color of water (I = white, 5 = deep blue) three-point rating of lighting (I = sunny, obvious shadows, 3 = cloudy, no shadows) five-point rating of photographic lighting accuracy (I = 100 dark. 5 = too bright) five-point rating of photographic color trueness (I = good. 5 = bad) horizontal distance in feet from edge of water surface to camera (0 when photo is taken from a bridge above the water) verticaJ distance in feet from water surface to camera VEG ROCK SKY WATER BED VIEW SOUND WIND WIDTH WCOLOR LIGHT PHOTOL PHOTOC HOIST VDIST . All independent variables bul FLOW estimaled from video sequences, 1092 cfs (30.92 mJ/s) in the Tucson case and at 1285 cfs (36.39 mJ/s) in the Fort Collins case, while peE reached a maximum at 1485 cfs (42.05 mJ/s) (Table 3). Given mean values ofthe non Row independent variables, the relationship of flow to scenic beauty was nearly identical across the rating experiment (SSE) models (Figure I). The rating experiments showed scenic beauty dropping, at a flow of about 2000 cfs (57 mJ/s), to the level it was at 100 cfs (2.8 mJ/s), while the paired-comparison experiment showed sce- nic beauty not reaching its 100 cfs (2.8 mJ/s) level until flow reached atmost 3000 cfs (85 m J Is). All 3 models were significant (P < 0.001). with standard errors ranging from 13 to 20% of the range in the scenic beauty metric. Analysis of residuals indicated in each case that the models did not violate the normality. linearity, and equality of variance assumptions of the regression proce- dure. These preferred flows typically occur during two short periods each year. In an average year. flows appro:lCimate the preferred levels in early June and mid-July (Figure 2). In between these two periods, flows are considerably higher (close to 2000 cfs (57 mJ/s)). During the rest of the year, flows are much below preferred levels. Small upstream reservoirs offer limited opportunities to alter flow and al- ready emphasize increasing late summer flows. Daubert and YOling's [19811 economic study found that 1791 shoreline recreationists' willingness to pay peaked at about 750 cfs (2:1.2 m)/s), somewhat lower than the scenic beauty results obtained here for persons who typically engage in similar actiVities. However, the difference is not necessarily simply due to the difference in dependent variable. Other important differences between the studies include the dif- ferent photographic media (still versus video) and the fact that Dauben and Young's photos were limited to flow levels below t 100 cfs (31 mJ/s), while this study included photos of flow levels of over 2600 cfs (74 m 3/s) (see Brown and Daniel [1987] on the effect of scene mixture on scenic beauty judgments). Different non Row variables entered the stepwise regres- sions of the different experiments (Table 3). Amounts of sky and bare soil or brownish hillside lowered SSE in both of the rating-based models_ The apparent importance of sky may be misleading, however, since percent in sky was signifi- cantly negatively correlated with percent rock and percent in trees and may enter the models more as a surrogate for the lack of rock and trees than because of a dislike for sky in the scenes. Also associated with increases in scenic beauty was percent of the scene in trees; decreases in scenic beauty were associaled with the percents of the scene in grass and exposed river bed. Grass was typically found at the lower elevations where arboreal vegetation was more sparse. Ex- posed river bed was associated with low flow levels. The remaining independent variables entering the models were related 10 view perspective, weather, and photographic quality. Distance of view, deeper water color, and general photog~aphic color trueness were associated with higher scenic beauty, while lack of sunlight (i.e., cloudiness) low~ ered scenic beauty. In addition to flow, only the lighting variable entered the more flow-focused paired-comparison model, but this sparsity may reflect the small degrees of freedom of the model. Stepwise regressions for the rating experiments were also performed for subsets of the cases (views) that depicted certain topographic and channel characteristics (e.g., rocky slopes, vegetated slopes, wide channel, narrow channel). Although the nonflow variables entering the models differed among the subsets, the relationship of flow to scenic beauty remained very similar to that found for the full set of cases. In other stepwise regressions, variables expressing the interaction of flow with other scene features were made available along with the simple terms. Resulting models tended to include some of these interaction terms, along with most of the independent variables included in the earlier (Table 3) models. but in all cases the coefficients for FLOW and FLOW' were hardly affected. ASSESSMENT FORMAT AND IMPORTANCE OF FLOW RATE We hypothesized that the importance of flow to scenic beauty would depend on the assessment formal and used two formats to obtain scenic beauty judgments. Emphasis on flow was purposefully avoided with the rating fonnat by including a wide selection of views to be rated that varied more dramatically in topography, channel morphology I depth of view, and vegetation than in flow volume and by not mentioning flow or any other specific scene feature in the instructions to respondents. The paired-comparison format tended to focus respondents' attention on flow by having about 60% of the scene pairs show the same view at different