NATIONAL PARK SERVICE Park and Recreation Structures

ALTHOUGH IT IS an inviolate principle with respect to national parks and monuments that artificial control of stream flow is to be rigidly avoided, the situation with respect to lesser parks is somewhat different. While it is felt that in some cases such artificial control has been exerted to the detriment of valuable natural conditions without creating adequate compensatory values, there are undoubtedly situations, such as that in which a serious regional shortage of facilities for water recreation exists, which justify this sort of modification of natural conditions. Those who feel that primary emphasis should be placed on preservation of really natural scenery and on historic and scientific values earnestly urge a careful weighing of all prospective losses and gains before any decision is made to create an artificial body of water in a park that is other than primarily for active recreation. Granting then the occasional wisdom of such undertakings, dams are considered with certain reservations to be within the scope of this compilation.

Because the large masonry or concrete dam is a complicated engineering problem, it will not be here discussed. Anything short of the most complete technical information might prove more misinforming than helpful. Furthermore, it has not so far proved very susceptible to coercive attempt to adapt its stubborn functionalism to a harmony with natural environment. It is true that large dams have been faced with stone to some softening of hard, rigid surfaces and lines. But always the failure of the undertaking to register anywhere near a perfect score in straining for harmony with environment has shown that the result has not justified the method. As with certain other facilities in parks, the large dam calls for a philosophical counting of its recreational blessings, and for a blindness to its incorrectible hostility to Nature. The recreational benefits of the made lake alone must be counted on to justify it, without reliance on its feeble efforts to appear a parklike "feature." This, in a development of any considerable size, it can never be.

Only dams that cleverly insinuate themselves into park settings by virtue of appearing to be waterfalls of natural origin, or lake-impounding topographic features having natural aspect in considerable degree, are considered to fall within the scope of this discussion. Herein, even in the case of such dams, concern is with appearance rather than with engineering principles. Readers whose interest goes deeper than the mere naturalizing of a minor impounding instrument will find A Manual for the Design of Low Dams, prepared for the Water Resources Committee of the National Resources Committee, authorative.

The small dam pretending to be a waterfall usually has a structural core wall against and over which the "naturalism" is applied as a veneer. Frequently the rock veneer follows too closely the regularity of the core wall, and betrays the fact that the dam is artificial. This can be avoided if the veneer strives for irregularity both in plan and in vertical section. The latter is accomplished, where ledge rock is native, by building out the lower courses in imitation of natural ledges. The surface treatment of the dam should acknowledge the geology of the area; in a gorge or glen in which rock stratifications are exposed, attempt should be made to bring to the face of the dam all the characteristics of the native ledge rock. The imitation of rocky ledges in a boulder-strewn setting would be sorely out of place—only a dam contrived by a massing of boulders would carry a suggestion of naturalness. Variety in size of the rocks will add much to the natural appearance of the dam. Likewise construction should insure such a distribution of water that all possible rock work of structural purport is screened by the flow. To have portions of the dam exposed during low water may unmask an otherwise well-contrived naturalism.

Pursuit of facts regarding the creation of this idyllic pool was deliberately sidestepped owing to a suspicion that man had little to do with. Suffice that it here represents the swimmin' hole of everyman's boyhood—as glorified in retrospect.

This delightful wading pool for youngsters in a metropolitan park is that very rare accomplishment—the spirit of great naturalness created without resort to a single detail truly imitative of Nature. This must be Art.

Swimming possibilities in parks and recreational areas can be classified broadly in two groups. Streams, rivers, and lakes comprise the one. The small pond created especially for swimming by the construction of a minor, and usually naturalistic, dam and the formal swimming pool make up the other. The first group is not a present concern; although it may involve the construction of dams, these are generally of such size that the attainment of park character is out of the question.

Only the second group claims our interest here and that largely for its inclusion of the naturalistic pool created by a dam that simulates a waterfall. It might be said that the aspect of the swimming pool and the relationship of the pool to the bathhouse are the points which engage our attention. The plates and illustrations which follow explore these points. There is no intent to treat in detail the construction of the swimming pool, which is an engineering and sanitation problem, so complex as to warrant thorough and detailed treatment if gone into at all. It is assumed that desired information bearing on the construction principles and details of swimming pools, being elsewhere available, will be elsewhere sought. These are ably set forth in Part 1100 Miscellaneous Structures of the Engineering Manual of the National Park Service.

To provide swimming in minor parks where active recreation is a strong demand and overcrowding seems unlikely, a plea is made for the return of the "old swimmin' hole" of fond recollection. The claims of hygiene make a strong case for the thoroughly modern, infection-controlled swimming pool and for the alternative of swimming in a large body of water which well dilutes, may it be said, the contagion risk of mass bathing. But there are areas primarily recreational serving small communities through which an uncontaminated stream may flow. The creation of a large artificial lake may be unwarranted for one or more of a number of reasons—limited area, lack of suitable site or sufficient funds for building a large dam, unreceptive topography, or perhaps only obstinate preference for Nature less modified. Here, if the flow of water is not seasonally stagnant, a swimming hole of "neighborhood" proportions, controlled against overcrowding and periodically checked for pollution, is certainly a logical project. A minor dam is the means by which this communal facility is brought into being, and, if it registers great naturalness, the swimming hole of boyhood's suitless swimming may be convincingly revived.

Pool, Prairie Creek State Park, California

Pursuit of facts regarding the creation of this idyllic pool was deliberately sidestepped owing to a suspicion that man had little to do with. Suffice that it here represents the swimmin' hole of everyman's boyhood—as glorified in retrospect.

Wading Pool, South Park, Pittsburgh, Pennsylvania

This delightful wading pool for youngsters in a metropolitan park is that very rare accomplishment—the spirit of great naturalness created without resort to a single detail truly imitative of Nature. This must be Art.

• Plate II G—1 — Plate II G—6