Quantitative Comparison of 

Some Aesthetic Factors 

Among Rivers 

Quantitative Comparison of 

Some Aesthetic Factors 

Among Rivers 

By l~na B. leopold 

GEOLOGICAL SURVEY CIRCULAR 620 

Washington 1969 
United States Department of the Interior 

ROGERS C. B. MORTON, Secretary 

Geological Survey 

V. E. McKelvey, Director 

First printing 1969 

Second printing 1 970 

Third p~inting 1973 

Free on application to the U.S. Geological Survey, National Center, Reston, Va. 22'192 
CONTENTS 

Page 

The problem --------------------------------------------------------------- 1 

Factors in comparing landscapes __ ----------------------------------------------- 1 

Universe within which comparison is made ------------------------------------ 3 

Ranking schemes ________ ---------------------------------------------------- 5 

Comparison of all surveyed sites ---------------------------- __ __________________ 6 

Factors selected for particular comparisons ------------------------------------ 7 

Hells Canyon compared with other United States river sites -------------------- 10 

Conclusion ____ -------------------- ______________________ --~-- _ ____________ ___ 12 

Description of sites --------------------------------------------------------- 13 

ILLUSTRATIONS 

Pagr 

FIGURE 1. Map showing location of sample sites -------------------------------- 4 

2-6. Graphs showing: 

2. Relation among uniqueness ratios of three groups of factors for 

surveyed sites ----------------------------------------- 8 

3. Analysis of valley character -------------------------------- 9 

4. Analysis of river character --------------------------- _______ 11 

5. Relation of valley to river character for surveyed sites in 

Idaho ------------------------------------------------- 12 

6. Relation of valley to river character for selected rivers in national 

parks and for Hells Canyon ----------------------------- 12 

TABLES 

Paga 

TABLE 1. Field evaluation of aesthetic factors at selected sites, Hells Canyon area, 

Idaho-evaluation numbers for descriptive categories ______________ 2 

2. Category assignment for aesthetic factors at the 12 localities on Idaho 

rivers -------------------------------------------------------- 5 

3. Uniqueness ratios for aesthetic factors at the Hells Canyon sites________ 6 

4. Summary-totals of uniqueness ratios of aesthetic factor values, Hells 

Canyon region ------------------------------------------------ 7 

5. Sites in order of uniqueness ratio _______ --------------------------------- 7 

III 

QUANTITATIVE COMPARISON OF SOME AESTHETIC FACTORS 

AMONG RIVERS 

By LUNA B. LEOPOLD 

It is difficult to evaluate the factors contributing to aesthetic or nonmonetary aspects of a 

landscape. In contrast, aspects which lend 

themselves to cost-benefit comparisons are now 

treated in a routine way. As a result, nonmonetary values are described either in 

emotion-loaded words or else are mentioned 

and thence forgotten. 

The present report is a preliminary attempt 

to quantify some elements of aesthetic appeal 

while eliminating, insofar as possible, value 

judgments or personal preferences. If methods 

of recording such factors can be developed, the 

results promise to be a useful, new kind of basic 

data needed in many planning and decisionmaking circumstances. Such data would be 

especially useful when choices must be made 

among alternative courses of action. Such data 

would tend to provide a more prominent consideration of the nonmonetary aspects of a landscape. 

Assignment of quantitative estimates to 

aesthetic factors leads not so much to ratios of 

value as to relative rank positions. In fact, 

value itself tends to carry a connotation of 

preference, whereas ranking can more easily 

be used for categorization without attribution 

of preference and thus it tends to a void the 

introduction at too early a stage of differences 

in preference. 

Because the Federal Power Commission has 

been studying an application for a permit to 

construct one or more additional hydropower 

dams in the vicinity of Hells Canyon of the 

Snake River, the localities studied for the 

p·resent discussion are in that region of Idaho. 

1 

Hopefully, the data collected will provi~e some 

useful information on factors related to nonmonetary values in the region. 

The present discussion has been kept. free o~ 

the preference judgments of the writer, and 

throughout the discussions observations are 

treated as facts. 

THE PROBLEM 

It is assumed that there is some benefit to 

society from the existence of some lardscapes 

in the United States that are unchanged by 

development. Interest in this benefit is evidenced by the passage of the Wilderr·~ss Act 

and by recent congressional action on the N ationa! Scenic Rivers bill. In light of this interest, 

it becomes relevant to consider ( 1) What 

criteria can be used to judge a given piece of 

landscape? (2) What other landscapes or ·features can it be compared with? and (3) How 

can any set of landscapes be ranked by priority 

if some, but not all, can be preserved free of 

development? The present discussion deals with 

all three of these questions in a tentative and 

incomplete way. Even an approach to the questions may contribute toward a gradual improvement in techniques of evaluation. Trus, one 

purpose of the present essay is to suggest some 

possible methodology as well as to present some 

facts collected in the field. 

FACTORS IN COMPARING LANDSCAPES 

If criteria are sought for comparisor of different landscapes or landscape featur~~s, it is 

necessary to list certain factors which cc nstitute 

the relevant features of a landscape. T11e relevant features, in the present discussion, are 
those which influence aesthetic impression and 

human interest in the area. These factors are 

relevant apart from the present or future intensity of use. The value to society may, from 

one standpoint, be increased in proportion to 

increased use by the public. On the other hand, 

increase of use is usually associated with decrease in the quality of the experience as use 

density passes some threshold value. 

The factors considered in the p1·a.sent analysis are of three types: physical features, biologic features, and human interest factors. They 

are listed in table 1 and compriP~ a total of 

46 items. Experience has shoWIJ that these 

factors are not equally sensitive or informative 

but it is hoped that experience would lead to 

improvement in the choice of factor~ considered. 

The widely used visitor-day method of measuring value to society suffers the grave disadvantage of failure to reflect the decrease in 

quality of experience as use density becomes 

large. Therefore, in preparing a list of factors 

relevant to aesthetic impression and human interest, intensity of use may be very misleading 

and is not considered in the following analysis. 

Instead, access provision-presence of roads 

and trails-presently extant is listed as a basic 

fact but with the recognition that this may be 

changed with time. 

Some of the factors, such as wif)th of river, 

are subject to direct measurement. Others must 

be estimated. Nonetheless, even those that are 

estimated can be assigned numerin.al positions 

on a comparative scale. Table 1 is a tabulation 

of definitions for it shows the range or position 

assigned to varying degrees of the presence 

or absence of each factor. All factors were 

assumed to range through a span of five degrees or categories. The physical factors which 

could be measured were divided by a geometric 

scale into the five categories. 

TABLE 1.-Field evaluation of aesthetic factors at selected sites, Hells Canyon are~ .. ' 

Idaho-evaluation numbers for descriptive categories 

Factor No. 

1 __________ _ 

2 __________ _ 3 __________ _ 4 __________ _ 5 __________ _ 

6 __________ _ 7 __________ _ 

8 _____ ------

9 __________ _ 

10 _________ _ 11 _________ _ 12 _________ _ 13 _________ _ 

14.---------

15_---------

1il _________ _ 17 _________ _ 18 _________ _ 

19 _________ _ 20 _________ _ 

21 _________ _ 22 _________ _ 

23 _________ _ 24 _________ _ 

25.---------

26 _________ _ 

Descriptive categories 

Physical factors: 

River width at low ft._ <3 

flow. 

Depth at low flow ______ ft__ <.5 

Velocity at low flow _____ ft__ <.5 

Bankfull de~th _________ ft__ <.1 

Flow variability____________ Little variation 

River pattern______________ Torrent Ratio of valley height to !5:;1 

width. 

Bed material _________ mm__ Clay or silt 

Bed. slope. _______ ft perf~-- <.0005 Basm area __________ sq mL. <1 

Stream order______________ ;:::2 

Erosion of banks._ _ _ _ _ _ _ _ _ _ Stable 

Deposition________________ Stable 

Width of valley flat _____ ft_ _ <100 

Biologic and water quality: Water color_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Clear and colorless. Turbidity ___________ mg/L. <25 

Floating material__________ None 

Water condition ___________ Poor 

Algae: Amount_______________ Absent 

Type ___ ----- ____ --___ Green on rocks 

Larger plants: Amount _______ ---_____ Absent 

Kind.________________ None 

River fauna _______________ None 

Pollution evidence__________ None 

Land flora: 

Valley________________ Opea 

Hillslope __ -------- _ __ _ Open 

27 __ - _ ----- _ Diversity_____________ Small 

28.--------- Condition _______ ---___ Good Human use and interest: 

Number of occurences of 

trash and litter per 100 ft 

of river: 

29---------- Metal________________ <2 

Evaluation numbers of descriptive categories 

2 

3 to 10 

.5 to 1 • 5 to 1 

.1 to 2 

Little variation 

Pool and riffle 

2 to 5 

Sand 

.0005 to .001 

1 to 10 

3 

----------------

----------------

100 to 300 

----------------

25 to 150 

Vegetation 

----------------

Open with grass 

and trees. Open with grass 

and trees. 

3 

10 to 30 

1 to 2 

1 to 2 

2 to 4 

Normal 

Without riffles 

5 to 10 

Mixture of sand 

and gravel. 

.001 to .005 

10 to 100 

4 

Slumping 

----------------

300 to 500 

Green tints 

150 to 1,000 

Foamy 

Good 

nii&i<>;n---- -----

E"1~Cieia &~d.-duck: 

weed. 

B "UBhy 

Brushy 

2 to 5 5 to 10 

2 

4 

30 to 100 

2 to 5 

3 to 5 

4 to 8 

E£hemeral or arge variation. 

Meander 

11 to 14 

Gravel 

.005 to .01 

100 to 1,000 

5 

----------------

----------------

500 to 1,000 

----------------

1,000 to 5,000 

Oily 

----------------

Wooded 

Wooded 

10 to 50 

5 

>100. 

>5. 

>5 . >8. 

Ephemeral or 

B~~~:J.ariation. 

~15. 

Cobbles or larger. 

>.01. 

>1,000. 

~6. 

Eroding. 

Large-scale deposition. 

>1,000. 

Brown. 

>5,000. 

Variety. 

Excellent. 

Infested. 

None. 

Infested. 

Cattail. 

Trees and brush. 

Trees and brush. 

Great. 

Overused. 

>50. 
TABLE 1.-Field evaluation of aesthetic factors at selected sites, Hells Canyon area, 

Idaho-evalttation numbers for descriptit•e categories-Continued 

Evaluation numbers of descriptive categories 

Factor No. Descriptive categories 

2 3 5 

so _________ _ 31 _________ _ ~~~=~ ~~~~ == = = = = = = = = = = = 

<2 

<2 2 to 5 2 to 5 

5 to 10 5 to 10 

10 to 50 

10 to 50 

>50. 

>50. 

32 __ -------- Material removable _______ _ sa _________ _ Artificial controls _________ _ 

84 _________ _ Ac~3~~~~al ____ ________ _ 

85 _________ _ Maaa uae _____________ _ 

86 _________ _ Local scene _______________ _ 

87 _________ _ Vistas _____________ - - - - - - -

88_--------- View confinement_------ __ _ 

Easily removed 

Free and natural 

Wilderness 

Wilderness 

Diverse views and scenes. Vistas of far 

places. 

Open or no obstructions. 

D!Jfirolt. 

Cont:-olled. 

Urba'l or paved 

at'cesa. 

Urba"' or paved acC'ellll. 

ClOSE'd or with- out diversity. Cl()SE'<{ or no vis•.as. 

ClOSE'd by hills, 

cliffs, or trees. sg ___ ------- Land use _________________ _ Wilderness Grazed Lumbering Forest and mixed 

recreation. 

Urbs"'ized. 

40 _________ _ Utilities __________________ _ 

41 _________ _ Degree of change __________ _ 

42 _________ _ Recovery potentiaL _______ _ 

43 _________ _ Urbanization _____________ _ 

"---------- 45 _________ _ 

46_--- ------

Scene unobstructed by 

c~;~r or electric 

Original. 

Natural recovery 

No buildings 

None 

None 

None 

UNIVERSE WITHIN WHICH COMPARISON 

IS MADE 

A central problem is the choice of area or 

universe within which landscape sites or types 

will be sampled. This universe might be the 

whole United States, for example. This would be 

justified by a desire to compare Hells Canyon 

with all the most spectacular landscape types 

which exist in the country. Such a choice would 

have the disadvantage of including environments so different that comparison is difficult. 

Another alternative would be to include only 

undeveloped hydropower sites because this is 

one of the characteristics of Hells Canyon at 

issue. Such a choice would, however, give more 

than needed emphasis to the economics of power 

development and perhaps insufficient emphasis 

to aesthetic values. The requisite basic data 

would be difficult to obtain. 

Another alternative would be to restrict the 

universe to the general region within which 

Hells Canyon lies on the grounds that the issue 

at hand concerns alternative choices of use 

within this region. 

It was decided that more than one universe 

should be used and thus the comparisons dis3 

Scene obstructed 

by utilities. 

MatE-rially alt.,.red. 

Natural change un1ikely. 

Man:v houses 

and buildings. Unmual interest. 

Man;". 

Many. 

cussed here involve the first and third alternatives mentioned above. 

In August of 1968 I toured central Idaho and 

chose 12 localities on Idaho rivers to represent 

a cross section of river valleys in th2 t region 

(fig. 1). At each site the 46 check-list factors 

were observed and assigned an evaluatjon number according to the five categories in table i. 

Category assignment for each factor at each site 

is shown in table 2. More sites could have been 

evaluated had time permited, and the ranking 

scheme would allow additional sites to be included whenever the data were obtained. But 

the 12 sites are sufficient to indicate the range 

of differences which exist in central Idaho for 

each of the landscape factors. 

Each site chosen has some possibility for 

power development. No attempt was made to 

estimate even roughly the power-generating 

capability of the rivers involved nor the economy of development. But the inclusion only 

of sites where some power development is at 

least physically possible gave the selected sites 

some commonness and excluded dese:~t landscapes and other scenic environments of different character. A photograph of eacl' site is 

shown at the end of this report. 
30' + + 

+ 

A 

0 Warm Lake 

+ + + 

River 

+ + 

0 10 20 40 MILES 

FIGURE 1.-Location of sample sites. 

4 
TABLE 2.-Category assignment for aesthetic factors at the 1! localitieB on Idaho rivers 

[Category number entered for each site is the nu~ber from 1 to 5 indicating range within which the measured or estimated quantlty falls] 

Descriptive categories 

Physical factors: River width at low flow ________________________ _ 

~:C!~t;ta\oio!o&w: :::::::::::::::::::: =:: :::: Bankfull depth _______________________________ _ 

Flow variability----- __________________________ _ River pattern _________________________________ _ Ratio of valley height to width _________________ _ Bed material _________________________________ _ 

Stream l::i:~: order ~= _________________________________ = = = = = = == = = :::::: = = == = = = =: = == = === = _ Erosion of banks ________ ---- __________________ _ Deposition ___________________________________ _ 

Width of valley flat ______ • ___________________ ._ 

Biol'l!!t~~~J!rt~~ -~~~~:- ________________________ _ 

~!~!1~t~di~~~~= ::::::::::::::::::::::::::::: 

Algae: Amount _______________________________ ----

Type_------------------------------------ Larger plants: Amount __________________________ ------.-_ Kind._----- ___________________________ --- River fauna ___________________________ ---_---- Pollution evidence ________________________ ---- __ 

Land flora: 

Valley------------------------------------

8l:i:-~ ~::::::::::::::::::::::::::::::: Human use and interest: 

Trash and litter: 

Metal ____________________________ --------

~~re~======= === ==== ::::::: = = ::::: = =: == :::: Material-removable. _______________ ---_-------- Artificial controls. _________________ ---_--------

Ac~~~![~------ -------- ___ ·-------- _ ---- __ Mass use ______________ ----- ____ -_--------- Local scene ________________ ----- ____ --_--------

Vistas._---- __ -------------------------------- View confinement.------ ____________ ----------- Land use _______ ---------- ___ ----- _______ ------ Utilities ________ --------_---- _______________ ---

~~J~~~~~== ::::::::::::::::::::::::::: fli:~c1!a~e;:: ::::::::::::::::::::::::::::: 

Misfits ______ -------_--------------------------

RANKING SCHEMES 

4 

2 

5 

8 

8 

2 

1 

5 

5 

4 

4 

1 

1 

8 

1 

1 

1 

8 

2 

1 

1 

1 

5 

1 

2 

2 

4 

1 

2 

2 

1 

1 

1 

8 

3 

8 

3 

3 

4 

4 

2 

2 

3 

1 

2 

1 

2 

4 

8 

4 

8 

8 

2 

1 

5 

4 

4 

4 

1 

1 

5 

3 

1 

1 

8 

2 

1 

1 

1 

5 

1 

1 

1 

2 

8 

1 

1 

1 

1 

1 

8 

3 

8 

3 

1 

2 

8 

2 

3 

4 

2 

1 

2 

Many schemes for comparison might be devised but each of them would have to be based 

on some philosophical framework. The philosophy underlying the scheme here is the following: Landscape which is unique-that is, different from others or uncommon-has more significance to society than that which is common. 

The unique qualities which enhance its value 

to society are those which have some aesthetic, 

scenic, or human interest connotation. Some 

unique qualities may present a human interest 

connotation for a reason of a different sort-it 

may be uniquely bad. But the principle remains 

the same. Human concern attaches to both. 

The ranking scheme consists of two parts 

which separately determine ( 1) the relative 

3 

4 

4 

4 

4 

3 

1 

2 

5 

5 

4 

5 

1 

1 

1 

2 

1 

1 

5 

2 

1 

1 

1 

5 

1 

4 

4 

2 

1 

2 

8 

8 

1 

3 

2 

2 

3 

8 

4 

4 

1 

2 

5 

2 

8 

1 

2 

5 

Category assigned to factors at indicated sites 

' 2 

8 

8 

8 

2 

1 

' 8 

8 

' 1 

1 

2 

4 

1 

1 

8 

1 

5 

1 

1 

5 

1 

' ' 1 

8 

2 

8 

2 

1 

1 

3 

8 

4 

5 

5 

4 

8 

3 

8 

2 

1 

1 

1 

5 

5 

5 

' 5 

5 

2 

' 5 

' 5 

5 

1 

1 

1 

8 

2 

1 

2 

8 

' 1 

1 

8 

2 

1 

1 

1 

8 

1 

1 

1 

1 

5 

2 

1 

1 

2 

1 

2 

1 

1 

5 

1 

5 

8 

1 

6 

8 

2 

8 

8 

4 

2 

1 

5 

5 

2 

8 

1 

1 

2 

5 

1 

1 

2 

8 

8 

1 

1 

4 

8 

4 

4 

2 

8 

1 

2 

1 

1 

1 

8 

3 

4 

5 

5 

4 

2 

3 

8 

3 

1 

1 

1 

7 

8 

2 

1 

8 

8 

4 

1 

1 

1 

4 

4 

8 

2 

4 

5 

8 

2 

1 

' 4 

5 

3 

2 

4 

2 

2 

4 

2 

1 

1 

1 

1 

8 

4 

4 

2 

4 

3 

2 

3 

8 

8 

8 

8 

1 

1 

8 

' 2 

4 

' ' 2 

1 

5 

' ' 5 

2 

1 

8 

8 

2 

1 

8 

8 

8 

1 

1 

' 2 

3 

4 

4 

2 

8 

8 

2 

1 

1 

4 

' 8 

4 

' 4 

2 

3 

4 

8 

3 

1 

2 

9 

5 

5 

4 

5 

' 2 

' 5 

8 

5 

5 

1 

1 

8 

3 

2 

1 

3 

2 

1 

1 

1 

' 1 

2 

1 

2 

8 

1 

1 

1 

1 

1 

4 

4 

2 

3 

4 

2 

2 

2 

3 

2 

4 

1 

2 

10 

5 

5 

' 5 

4 

2 

' 5 

' 5 

5 

1 

2 

2 

2 

2 

1 

5 

2 

8 

1 

1 

5 

1 

2 

2 

8 

1 

1 

1 

1 

1 

1 

1 

1 

1 

2 

3 

1 

1 

1 

1 

2 

' 2 

1 

11 

' 2 

' 8 

' 1 

8 

5 

5 

8 

' 1 

1 

2 

1 

1 

1 

5 

2 

1 

1 

1 

5 

1 

5 

' 2 

2 

2 

2 

1 

1 

1 

2 

2 

5 

5 

5 

1 

1 

2 

2 

2 

2 

1 

1 

12 

4 

' 4 

4 

4 

2 

2 

5 

5 

4 

5 

1 

1 

2 

3 

3 

1 

2 

2 

1 

1 

1 

3 

3 

5 

4 

2 

1 

2 

1 

1 

1 

8 

3 

8 

4 

5 

' 4 

8 

3 

8 

8 

2 

1 

1 

uniqueness whether the unique qualities have 

aesthetic, scenic, or human interest connotation 

or not, and (2) the relative uniqueness when 

the unique qualities are arranged in hiel~archical 

order of aesthetic interest or are chosen to do so. 

The first part is accomplished by the following procedure. If a site factor is, for example, 

one among 12 of the same category, the site 

shares this characteristic with 11 others. It is 

unique in the ratio of 1 to 12 or its uniqueness 

ratio is 1 : 12 (.08). If no other site s'hares the 

same category position, then the site has a 

uniqueness ratio of 1 : 1 ( 1.0). The uniqueness 

is thus defined on a scale of 0 to 1.0. 

In the present data, which include 12 sites, 

the minimum uniqueness ratio is 1 : 12 or .08. 

The uniqueness ratios for each of the 4~ factors 
TABLE a.-Uniqueness ratios for aesthetic factors at the Hells Canyon sites 

Categories and 

factor No. 

Phyaieal: 

2 3 5 

Site No. 

6 7 8 9 10 11 12 

~_ ____________________ 0.14 0.14 0.14 0.14 0.33 0.50 0.50 0.14 0.33 0.33 0.14 0.14 

2--------------------- .17 1.00 .50 .17 .33 .17 .17 .17 .33 .33 .17 .50 3 _____________________ 1.00 .12 .12 .5o .12 .50 t.oo .12 .12 .12 .12 .12 

4.-------------------- .17 . 17 . 33 . 17 . 33 . 17 .17 . 33 . 33 . 33 .17 . 33 

5--------------------- .11 .11 .50 .11 .11 .11 1.00 .11 .11 .11 .50 .11 

6--------------------- .17 .17 .50 .17 .33 .17 .17 .17 .33 .33 1.00 .50 7 _____________________ .10 .10 .10 1.00 .10 .10 1.00 .10 .10 .10 .10 .10 

8 _____________________ .10 .10 .10 1.00 .10 .10 1.00 .10 .10 .10 .10 .10 

9--------------------- .20 .25 .20 .50 .25 .20 1.00 .25 .50 .25 .20 .20 

10-------------------- .17 .11 .n .33 .33 .sa .17 .17 .33 .33 .33 .11 

11-------------------- .20 .20 .17 .20 .17 1.00 .20 .17 .17 .17 .20 .17 

12-------------------- .10 .10 .10 .10 .10 .10 1.00 1.00 .10 .10 .10 .10 13 ____________________ .10 .10 .10 .10 .10 .10 .50 .10 .10 .50 .10 .10 

14-------------------- .33 1.00 .50 .20 .50 .20 1.00 .38 .33 .20 .20 .20 

SubtotaL ____ • ______ --3 .-0-6 --3-.-73--3-.-53--4-.6-9--3-.2-0--3-.7-5--8-.8-8--3-.2-6--3-.-28--3-.3-0--3-.4-3--2-.84-

Biologic: 

15-------------------- .50 .20 .50 1.00 .20 .50 .50 .20 .20 .50 

16-------------------- .17 .17 .17 .17 .25 .17 .50 .25 .25 .25 11-------------------- .09 .09 .09 .09 .09 .09 1.00 .09 .09 .09 

18-------------------- .20 .20 .33 .20 .33 .33 1.00 .20 .20 .33 

19-------------------- .14 .14 .14 1.00 .33 .33 1.00 .33 .14 .14 

20-------------------- .17 .17 .17 1.00 .50 .33 .50 .33 .17 .33 

21-------------------- .09 .09 .09 .09 .09 .09 1.00 .09 .09 .09 22-------------------- .09 .09 .09 .09 .09 .09 1.00 .09 .09 .09 23____________________ .17 .17 .17 .17 .50 .33 1.00 .33 .33 .17 

24 ____________________ .14 .14 .14 .14 .50 .50 1.00 .50 .14 .14 

25____________________ .25 .50 .33 .33 .50 .33 .25 1.00 .25 .25 

26 ____________________ .33 .33 .17 .17 .33 .17 .33 .17 .33 .33 

27 ____________________ .33 .17 .17 .50 .50 .17 .33 .33 .17 1.00 

28____________________ .25 .20 .25 .20 .20 .20 .33 .33 .20 .25 

.50 

.17 

.09 

.38 

.14 

.17 

.09 

.09 

.17 

.14 

.50 

.17 

.17 

.88 

----------------------------------------- Subtotal ____________ 2.92 2.66 2.81 5.15 4.41 3.67 9.74 4.24 2.65 3.96 3.06 

.20 

.50 

.09 

.88 

.14 

.17 

.09 

.09 

.50 

.50 

.50 

.17 

.17 

.25 

8.70 

Human interest: 

29-------------------- .20 .17 .20 .20 .17 .17 .17 l.ob .17 .17 .20 .20 so ____________________ .33 .17 .ss .ss .17 .ss .17 .stl .17 .17 .33 .17 

81____________________ .11 .11 1.00 .50 .11 .11 .11 .50 .11 .11 .11 .11 

32-------------------- .08 .08 .08 .08 .08 .08 .08 .08 .08 .08 .08 .08 33 ____________________ .12 .12 .33 .12 1.00 .12 .ss .12 .12 .12 .12 .33 

34____________________ .20 .20 .33 .20 .33 .20 .33 .33 .33 1.00 .83 .20 

35____________________ .20 .20 .50 .20 .50 .20 .33 .33 .33 .50 .50 .20 

36____________________ .25 .25 .25 .33 .50 .33 .50 .25 .50 .50 1.00 .33 

37 _______ ------------- .25 .25 .25 .25 . 50 . 25 . 50 . 50 .25 . 50 . 25 .25 

38. ___________________ .33 .50 .25 .33 .50 .33 .33 .25 .25 .33 .83 .25 

39 ____________________ .17 .25 .17 .17 .25 .17 .25 .17 .25 .50 .50 .17 

40 ____________________ 1.00 .25 .25 .25 .25 .33 .25 .33 .33 .25 .25 .25 

41-------------------- .20 .20 .20 .20 .50 .20 .20 .20 .20 .50 .20 .20 

42-------------------- .50 .17 .50 .17 .50 .17 .17 1.00 .17 1.00 .50 .17 "-------------------- .20 1.00 .20 .20 1.00 .20 .20 .20 .20 .20 .20 .20 

44-------------------- .33 .33 .33 .33 1.00 .33 .38 .38 .50 .50 .33 .88 

45____________________ .50 .11 .11 .11 1.00 .11 .11 .11 .11 .50 .11 .11 

46-------------------- .12 .25 .25 .12 .12 .12 .12 .25 .25 .12 .12 .12 

--------------------------------------------------------- SubtotaL___________ 5.09 4.61 5. 53 4.09 8.48 3. 75 4.48 6.28 4.32 7.05 5.46 3.67 

==================================================================== Total_______________ 11.07 11.~ 11.87 13.93 16.09 11.17 23.10 13.78 10.25 14.31 11.95 10.21 

and for the 12 sites appear in table 3, which also 

contains the sum of uniqueness ratios. Subtotals 

for the three groups of factors, physical, biological, and human interest, as well as the sums 

of all three, are summarized in table 4. 

COMPARISON OF 'ALL SURVEYED SITES 

It will be understood that any group of riverside sites selected in central Idaho will display 

mountain scenery of high distinction, for the 

region is rugged, forested, and has many clear 

mountain rivers. Therefore the sample includes, 

nearly without exception, country of high 

aesthetic quality. It must be expected then that 

variance among sites is less than if other landscapes that are not so appealing were included. 

6 

Moreover, because the sites are in the same 

region and have the same type of forest, in 

many respects they are very similar. 

Uniqueness ratios for each site, presented in 

table 4, have been arranged in order of rank and 

are listed separately in table 5 for the three 

main categories and for the total -r1alues. 

Site 7 is the most unique for i~. ranks first 

in physical, biologic, and total uniqueness. Site 

7, Little Salmon River, near N e'~v Meadows, 

is the only site which has a sluggish, algae infested, murky stream of small gradient that is 

evidently nutrient-enriched frcm agricultural 

use and, to a lesser extent, from urt'ln wastes. 
TABLE 4.-Summary-totals of uniqueness ratios of 

aesthetic factor values, Hells Canyon region 

Site Aesthetic factors 

Physical Bioiogfe Human 

1----------------------- 8.06 ~----------------------- 8. 78 ~----------------------- 8.68 

&_______________________ 4----------------------- 8.10 4.69 

8_______________________ 8.75 ?_______________________ 8.88 

8----------------------- 8.18 9_______________________ 8.18 

10______________________ 8.80 

11---------------------- 8.48 11 ______ -- __ --_ __ _ _ _ _ _ _ _ I. 84 

1.92 

2.68 

1.81 

5.15 

4.41 

8.67 

9.74 

4.24 

2.65 

8.96 

8.06 

8.70 

interest 

5.09 

4.61 

5.68 

4.09 

8.48 

8.75 

4.48 

6.28 

4.82 

7.05 

5.46 

8.67 

Total 

11.07 

11.00 

11.87 

18.98 

16.09 

11.17 

28.10 

18.78 

10.25 

14.8t 

11.95 

10.21 

TABLE 5.-Sites in order of uniqueness ratio 

Rank Aesthetic factors 

Physical 

1------------------------ 7 

4 6 4------------------------ 2 5------------------------ 8 

8------------------------ 11 1------------------------ s__ _ _ _ _ ___ _ _ __ _ _ _ ___ ___ __ 10 9 

9------------------------ 8 

10----------------------- 5 11----------------------- 1 

12 __ --------------------- 12 

Biologic 

7 

4 

6 

8 

10 

12 

6 

11 

1 

8 

2 

9 

Human 

interest 

5 

10 

8 

8 

11 

1 

2 

7 

9 

4 

6 

12 

Total 

7 

5 

10 

4 

8 

11 

6 

8 

12 

1 

2 

9 

Site 5, the Snake River in Hells Canyon, has 

the second largest total uniqueness ratio. It has 

a high total score because it ranks first in human interest and third in biologic factors. Surprisingly, it ranks 1Oth (or not unique among 

the -sites) in physical factors. Site 10, Salmon 

River at Carey Falls, is third in total uniqueness 

because it is second in human interest and fifth 

in biologic factors. Again, its position is seventh 

in physical factors. 

A visual picture of the position of various 

sites in the uniqueness scale can be obtained in 

figure 2, in which the values of human interest 

and biologic uniqueness are, respectively, the 

ordinate and abscissa, and physical uniqueness 

is written in next to each plotted point. 

In figure 2, site 7 stands alone because of its 

high position on the biologic scale. It is the only 

enriched (polluted) river among the sites surveyed. Sites 5, 10, and 8 stand more or less 

alone because of low positions on the biologic 

scale and high positions on the human interest 

.scale. All other sites form a bunch of approximately equal characteristics. 

7 

FACTORS SELECTED FOR P ARTICUI.AR 

COMPARISONS 

The data allow site comparisons for groups 

factors selected to represent particular aspects 

of the landscapes. Although selection of factors 

involves judgment as to which facto!"s appropriately describe certain landscape char~eteristic, grouping of selected factors need not involve assignment of preference. Facto:-:- selection can then be merely a subdivision of objective basic data. 

Landscape scale is a way of expressing one 

aspect of bigness or grandeur. The Tetor Range 

in Wyoming is often called the Alps of North 

America. Its spectacular character com~s, to a 

great extent, from the proximity of t1' ~ high 

peaks to the adjacent valley floor of ~T ackson 

Hole. 

One way to define this relationship is the 

height of adjacent mountains compared to the 

width of the valley floor. Where high mountains exist next to narrow valleys, the scenery 

is generally of large scale. In contrast, low hills 

adjacent to wide valleys lack the grandeur of 

large landscape scale. 

To describe this, the bottom graph of figure 

3 is a plot of height in feet of mountainr ( ordinate) and width in feet of the floor of the adjacent valley (abscissa). On this plot, sites 5 

and 10 fall in a zone of large-scale landscapes 

and other sites fall in a more subdued scale. 

To reduce the combination of height of hills 

and width of valley to a single parameter, here 

called landscape scale, the projection of the 

position of each plotted point on a 45 o diagonal 

line was carried out. This projection is in1icated 

by the dashed lines leading from each :t: "lint at 

a 45° angle upward to the right in th~ lower 

graph. 

The projection could have been made on to 

a line having some other slope. The choice of a 

45 o line is an assignment of equal weight to 

ordinate and to abscissa value. 

Thus, the position of each point proje~~ted on 

to the diagonal line is a quantitative ass~ssment 

of position on th~ yardstick of landscap~ scale, 

which can be used for construction of a new 

graph as has been done in the central portion 

of figure 3. 
9~-----~~----~~------~~------~~-------,~-----,~----~,~~-----------------, 

V) 

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c( 

LL. 

1--

V) 

LLJ 

0::: 

LLJ 

1--

:z 

V) 

V) 

LLJ 

:z 

LLJ 

8-

7f6f--

g. 3r-

-:z 

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LL. 

0 

....1 2 f- c( 

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1--

1r2 

63.53 

3 

3.20 

56 

63.30 

JO 

L.\3.26 

8 

3.06 3.43 

J6 6JJ 

I::J.3.73 

I::J.3.28 

9 

3.75 

6 6 6 2.84 

J2 

-

EXPLANATION 

Uniqueness 

3 43 of physical · -factors 

ft-site 

number 

I I 

Totals of uniqueness ratios of sHveyed sites 

-

-

-

-

-

-

-

o~----~'~----~'------~'------~~------~~------~'------~'----~'------~1----~ 1 2 3 4 5 6 7 8 9 10 

TOTAL UNIQUENESS RATIO FOR BIOLOGIC FACTORS 

FIGURE 2.-Relation among uniqueness ra~ios of three groups of factors for surveyec;1 sites. 

Using the position along the diagonal as a 

measure of landscape scale, the middle graph 

of figure 3 plots landscape scale against the 

degree of view confinement. Where distant 

vistas are available in large-scale landscape, 

one has the impression of spectacular scenery. 

In contrast, confinement of view by heavy cover 

or where views are blocked by adjacent hills, 

especially when combined with subdued landscape, the result is aesthetically ordinary from 

the scenic point of view. 

In the center diagram, the position of each 

point can again be projected to a 45° line providing a new yardstick of landscape scale com8 

bined with availability of sceni~ outlooks or 

vistas, the two factors being giver equal weight. 

The result is a measure of what is called landscape interest and it varies from spectacular to 

ordinary. 

One of the considerations in croosing among 

alternative areas to protect fron1 development 

is the degree of wildness or the freedom from 

the usual encroachments of civilization. One 

factor in the checklist of surveyed characteristics is the degree of urbanizaticn, which was 

defined as the totality of buildings, houses, 

roads, utilities, and other earmarks of change 

by man's use. As before, using the position of 
tLJ..J 

~ 5000 t-----....,....,.._ 

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....... 

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....J 

....J 

....... 

:c 

>- 1000 t------------';~~----;--------1----,.'---~ 

cc 

0::: 

c:t: 

LJ..J 

z: SOOt---~~~~~----;-~~-~-~ 

L1.. 

0 

t-

:c 

(.!:' 

....... 

LJ..J 

:c 

100~-----~--~----------~--~ 

100 500 1000 5000 10 ()()() 

WIDTH OF VALLEY, IN FEET 

FIGURE 3.-Analysis of valley character. 

9 

Note: Site number 

is labeled beside 

each plotted point. 
each site on the diagonal line which is a yardstick of landscape interest as an abscissa, an 

ordinate representing urbanization is used to 

construct the upper diagram. The combination 

of spectacular scenery and low urbanization 

falls in the left lower zone of the upper graph, 

and the ordinary and urban conditions fall in 

the upper right. The combination of landscape 

interest and urbanization, each given equal 

weight, is represented by projection onto a 45 o 

diagonal in the upper graph, and this yields a 

scale of valley character. 

These considerations show clearly that sites 

5 and 10, Snake River at Hells Canyon and the 

wild reach of Salmon River at Carey Falls, are 

unique to a high degree. All other sites studied 

are in a cluster of points to the right and upper 

part of the upper graph. 

A comparable analysis can be made of river 

characteristics. Experience indicates that the 

grandeur or majesty of a river is dependent on a 

combination of size and apparent speed. Small 

rivers tumbling over a succession of falls are 

more impressive or are more aesthetically appealing than a large river which appears sluggish. The latter characteristic is not so much 

dependent on velocity, which is usually poorly 

estimated by the untrained eye, as it is on 

appearance of speed judged mostly by the 

waves and surface ripples caused by rapids or 

falls. 

As a measure of scale, the lower graph of 

figure 4 is a plot of river width as a function of 

water depth. Deep and wide rivers appear in 

the upper right area of the graph. 

The relative position of each point with respect to the lower left or upper right zones, is 

indicated by the projection of the position on 

to a 45 o line which becomes the abscissa for 

the center graph. The ordinate is a measure of 

the occurrence or absence of riffles, rapids, and 

falls. Thus, sites which fall in the upper part of 

the diagram are large and rapid and those in 

the lower zone are small and placid. 

The combination of river size and prevalence 

of rapids is, as before, obtained by projecting 

the points on to a 45 o line in figure 4 which is 

a yardstick of river character. 

10 

Now the character of valley can be put together with the character of river which is 

done in figure 5. The ordinate is taken from 

the position of each site on the s~ale of valley 

character, figure 3. The spectaer lar and wild 

is high on the ordinate scale and the urban 

and ordinary is low on the scale. The abscissa 

is taken from the scale of river character, 

figure 4. It is a measure of the character of 

the river; lefthand positions are f"'lall and placid rivers, and righthand positions are large 

and rapid. 

These graphs add information over and above 

the uniqueness ratios because they show associations among relevant characteristics. The 

efficacy of the analysis is indicated by the fact 

that these associations give a wider ~pread between sites than do uniqueness ratios alone, 

but at the same time they do rr:»t contradict 

relations shown by those ratios. 

Hells Canyon, site 5, appears in a category 

of its own with respect to character of valley 

and river, a fact already showr by the uniqueness ratios. The nearest to it in these respects is site 10, Salmon River at Carey Falls 

which indeed is, from subjective impression, 

more like Hells Canyon than any other site. 

Site 7, the only nutrient-enriched site, becomes 

a part of the preponderance of points, usual or 

ordinary in its river and valley character. 

HELLS CANYON COMPARED W~TH OTHER 

UNITED STATES RIVER ftlTES 

As stated earlier, the choice of a universe 

within which to choose sites for comparison 

poses some problems. For this reason, two universes were used. The first consists of the 12 

sites in the same region of Idaho; the second 

will now be discussed. 

The purpose of the present analysis is to provide some quantitative information bearing on 

the social importance of Hells Canyon preserved 

in its present undeveloped condit~'ln. Such preservation would imply that it rarks among the 

best in American river scenery. It is logical 

then to compare Hells Canyon with some of 

the American landscapes acknowledged to be 

of high aesthetic quality. Accordir~ly, four sites 

in national parks are used for c.omparison on 

the assumption that national pa:rk status is a 
-c... 

~ 

l.&.J 

~ 

c:: ~<( 

L1..J -J5 

1-

u 

c:t: 

~ 

c:t: 5 4 

~ 

L1..J 

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.......... 

~ 3 

LL.. 

0 

L1..J 

....J 

5 c2 V>t; 

<( 

_J 

c... 

C) 

~1 

z 

.......... 

... 

Note: Site number 

is labeled teside 

each plotte~ point. 

~0 5 

~100r-----~~~~~~--~~----~----+----------­

o 

.......... 

3: 

~ 50r---------~~~r~----------~----~--------~ L1..J 

> 

.......... 

~ 

10~--------~~--~--------~----L---------~ 0.5 1 5 10 50 

RIVER DEPTH, IN FEET 

FIGURE 4.-Analysis of river character. 

formal recognition of exceptional aesthetic 

quality. 

Within these four national parks, sites were 

chosen in a manner comparable to the Idaho 

sites already discussed, in that the factors to 

be rated are those observed at rivers edge. The 

four rivers chosen are: site 13, Merced Ri~er in 

Yosemite National Park; site 14, Grand Canyon 

of the Colorado River; site 15, Yellowstone 

River near Yellowstone Falls; and site 16, 

11 

Snake River in Grand Teton Nationa] Park, 

below Jenny Lake. 

For eacn site visualized, the same factors 

were evaluated or measured as were needed to 

construct figures 3, 4, and 5; specifically, these 

were valley width, height of mountains bounding valley, availability of vistas, urbanization, 

river width, river depth, and occurrence of 

riffles and rapids. 

The quantities assigned to the four national 
7 I I I I I lo.s 

6t- o• -

0: 

Lt.J 

t;sr- o' o3 -

~ c( 

::I: o" 

u4t- -

>- 4 Lt.J o' o ....J 

....J o• c( o1 06 >3t- o,2 -

LL. o2 0 

Lt.J 

~2- -

u 

V) 

1- -

l l I I I I 0 1 2 3 4 5 6 7 

SCALE OF RIVER CHARACTER 

FIGURE 5.-Relation of valley to river character for 

surveyed sites in Idaho. 

park sites utilized the same scales and definitions as had previously been used. Graphs comparable to figures 3 and 4 were constructed as 

described earlier and from them a graph comparable to figure 5 was made which appears 

here as figure 6. 

In this comparison it can be seen that combining river and valley characteristics, which 

obviously excluded many other noteworthy aspects of the respective parks, only Grand Canyon of the Colorado appears in the same 

category as Hells Canyon. The Merced River 

in Yosemite National Park is in a spectacular 

valley but is not an unusual river. It therefore 

plots in a lower left position not unlike most of 

the Idaho river sites. Yellowstone River and 

the Snake River in Grand Teton National Park 

are intermediate in position. 

12 

7 

~ 6r 

~5 :I: 

u 

>-

LLJ 

j4 

c::( 

> 

LL. 

03 

LLJ 

......J 

c::( 

u (/)2 

0 

Colorado River in 

Grand Canyon 0 

® J4 

Hells Canyon 5 

Yellowstone River 

in Yellowstone National Park 0 15 

Snake River in o16 

Grand Teton 

National Park 

Merced River in 013 

Yosemite National Park 

2 3 4 5 6 

SCALE OF RIVER CHARAr.TER 

7 

FIGURE 6.-Relation of valley to river character for 

selected rivers in national parks and for Hells Canyon. 

CONCLUSION 

Quantitative evaluation of river and valley 

characteristics was made on 12 sites in Idaho. 

These were analyzed without introduction of 

any personal preference or bias. Hells Canyon 

of the Snake River was shown to b~ unique, and 

its evaluated rank or position was approximated 

only by the main Salmon River in its wilderness reaches. 

A further comparison of a few selected river 

and valley characteristics was mac~ with rivers 

in four well-known national parks. Hells Canyon was clearly unique and compz.rable only to 

Grand Canyon of the Colorado River in these 

features. 
DESCRIPTION OF SITES 

SITE 1.-Wood River, 6 miles above Ketchum, Idaho, 

at Forest Camp in Sawtooth National Forest on U.S. 

Highway 93. A broad river valley closely forested 

with spruce and fir is set in rolling open hills, patched 

with timbered areas and interspersed with open 

grasslands. The stream is clear and gentle in gradient 

and is easily accessible along most of its length 

from the paved highway which goes up the valley. 

Several forest campgrounds exist and a considerable 

length of the valley is within the National Forest. 

SITE 3.-Middle Fork Salmon River at Dagger Falls, 

Idaho, in Challis National Forest, at end of a side 

road off the road between Cape Horn and Warm 

Lake. In a gorgelike valley bottom, a large clear 

river courses between rock outcrops and tumbles 

over gravel or bedrock riffles or falls. Though the enclosing mountains are many hundreds of feet high, 

the views are confined by heavy spruce and fir timber 

and are restricted mostly to view of nearby hilltops 

only. The gravel forest road dead ends at the river 

site, where there is a forest campground. At some 

seasons of the year, salmon can be observed leaping 

the falls in migration. The site is a launching place 

for river boat expeditions. 

13 

SITE 2.-Salmon River, a quarter of a mile above 

Stanley, Idaho, on U.S. Highway 93. A broad nearly 

treeless valley, surrounded by low hills, is traversed 

by a large clear stream of very uniform gravel bed. 

The stream is nearly straight and is lined in some 

places by willow brush. Some low forest-covered 

hills can be seen in the distance. The valley contains 

some ranches and sporadic settlements. Access to the 

river is extant for some miles from the paved highway which goes along the valley. 
SITE 5.-Hells Canyon of the Snake River, below Hells 

Canyon Dam. In broad green smooth pools alternating 

with sharp rapids, the very large river flows between 

rocky spurs which nearly everywhere reach to the 

water's very edge. The rough and bare spurs rise 

in cliffs and steps upward at a steep angle from 

the river to what seems immense heights. On bends 

in the canyon and where one can look up steep 

tributary valleys, far vistas of still higher cliffs and 

mountain tops are visible. The immense river is 

nearly dwarfed by the imposing rock palisades, 

colored in the dark tones of basalt and reddish 

metamorphic rock. Clusters of trees and open patches 

of grass hang on steep scarps or on local level ramparts. Access through much of the distance is by 

trail cut in the steep hillside rock and by obscure 

roads leading to a few widely scattered ranches. 

SITE 4.-South Fork Salmon River, near Warm Lake, 

Idaho, at campground. In a broad open valley, a 

nearly clear stream flows between borders of willow, 

alder, and fir woods and is incised about 8 feet 

below the general valley floor. Distant forested hills 

are visible. Except for its incised position below the 

grasscovered terrace, the river is accessible from the 

road which follows the valley. 

SITE 6.-Weiser River at Evergreen Forest Camp on 

U.S. Highway 95, south of Pine Ridge, Idaho. A small 

boulder stream of cloudy water flows in a narrow, 

brush-enclosed notch surrounded by low hilltops completely forested in cutover and second growth fir 

and spruce. A well-traveled, paved highway goes 

along the valley cut into the hillside. Views are 

absent owing to confining adjacent hills and heavy 

timber. 
SITE 7.-Little Salmon River, 6 miles north of New 

Meadows, Idaho, on U.S. Highway 95. A shallow, 

turbid, and algae-infested stream curves in a meandering and partly braided course through a wide, 

flat valley floor. Vegetation on the nearby low hills 

is mixed between pine and grass and there are open 

views of more distant hillsides of low mountains 

covered by scattered timber. 

SITE 9.-Salmon River, 2 miles below Riggins, Idaho, 

near U.S. Highway 95. A broad, deep, nearly clear 

river of deep green flows smoothly between rugged 

cliffs and rock slopes pitching sharply down to the 

water's edge with only occasional gravel beach. The 

cliffs rise tier on tier in treeless giant steps. Small 

narrow valleys notching the rock slopes hold ribl:lons 

of pine and fir. The valley, despite its steep sides, 

is wide enough to provide long vistas to distant and 

even higher mountain tops. The paved highway goes 

down the valley on a terrace some 40 feet above the 

river. 

SITE 8.-Little Salmon River, below Boulder Creek, 4 

miles south of Pollock, Idaho. A nearly clear river 

alternates between bouldery pools and sharp rapids 

in a shallow but narrow valley bounded by completely forested hillslopes. Access is available for 

long distances through the paved · highway which 

follows the valley. 

15 
SITE 11.-French Creek, 1 mile above mouth where it 

joins main Salmon River and at place where the road 

up French Creek leaves the valley and enters the 

switchback zone up the mountainside. A narrow, 

steep-sided, forested valley hides a rushing torrent. 

Near the stream no concept of the depth of valley 

or height of mountains can be gained for there are 

no lookout openings. An unpaved road steeply follows up the valley and then turns into narrow and 

precipitous switchbacks up the mountain, where the 

road is labeled "single lane, no turnouts." 

16 

SITE 10.-Salmon River at Carey Falls, 20 miles abo •. _ 

Riggins, Idaho. A large clear green-hued river tumbles over big rapids alternating with fast pools. 

A mixed fir and open grass parkland rises steeply 

from the water's edge and broad V -shaped valleys 

open long vistas to forested peaks in the far high 

horizon. So steep and high are the sides of the main 

valley that the nearby mountain tops are hidden, but 

long vistas in several directions display ever more 

distant mountain crests in receding waves of horizons. 

An unpaved road winds dangerously along a cut in 

the steep mountainside and narrows to a single track 

which ends at Carey Falls. 

SITE 12.-North Fork Payette River, near Smiths 

Ferry, on State Highway 15. In a forested, broadly 

open valley a swift, somewhat murky river of high 

gradient tumbles in a nearly continuous rapid. A 

railroad, powerline, and paved highway follow the 

river closely. No distant mountains are visible 

despite the broad openness of the valley. 

-1< U.s. GOVERNMENT PRINTING OFFICE, 1973 0-543-57~