The rapid and destructive erosion of the earthen roof covering must have early stimulated the pueblo architect to devise means for promptly distributing where it would do the least harm, the water which came upon his house. This necessity must have led to the early use of roof drains, for in no other way could the ancient builders have provided for the effectual removal of the water from the roofs and at the same time have preserved intact the masonry of the walls. Unfortunately we have no examples of such features in the ruined pueblos, for in the destruction or decay of the houses they are among the first details to be lost. The roof drain in the modern architecture becomes a very prominent feature, particularly at Zuñi.

Fig.39.Single stone roof drains.
Fig.40.Trough roof drains of stone.
Fig.41.Wooden roof drains.

These drains are formed by piercing an opening through the thickness of the coping wall, at a point where the drainage from the roof would collect, the opening being made with a decided pitch and furnished with a spout or device of some kind to insure the discharge of the water beyond the face of the wall. These spouts assume a variety of forms. Perhaps the most common is that of a single long, narrow slab of stone, set at a suitable angle and of sufficient projection to throw the discharge clear of the wall. Fig. 39 illustrates drains of this type, No. 1 being a Tusayan example and No. 2 from Zuñi. It will be noted that the surrounding masonry of the former, as well as the stone itself, are much ruder than the Zuñi example. Another type of drain, not differing greatly from the preceding, is illustrated in Fig. 40. This form is a slight improvement on the single stone drain, as it is provided with side pieces which convert the device into a trough-like spout, and more effectually direct the discharge. No. 1 is a Tusayan spout and No. 2 a Zuñi example. Wooden spouts are also commonly used for this purpose. Fig. 41 illustrates an example from each province of this form of drain. These are usually made from small tree trunks, not exceeding 3 or 4 inches in diameter, and are gouged out from one side. No tubular specimens of wooden spouts were seen. At Tusayan the builders have utilized stone of a concretionary formation for roof drains. The workers in stone could not wish for material more suitably fashioned for the purpose than these specimens. Two of these curious stone channels are illustrated in Fig. 42. Two more examples of Tusayan roof drains are illustrated in Fig. 43. The first of the latter shows the use of a discarded metate, or mealing stone, and the second of a gourd that has been walled into the coping.

Fig.42.Curved roof drains of stone in Tusayan.
Fig.43.Tusayan roof drains; a discarded metate and a gourd.

It is said that tubes of clay were used at Awatubi in olden times for roof drains, but there remains no positive evidence of this. Three forms of this device are attributed to the people of that village. Some are said to have been made of wood, others of stone, and some again of sun-dried clay. The native explanation of the use in this connection of sun-dried clay, instead of the more durable baked product, was that the application of fire to any object that water passes through would be likely to dry up the rains. It was stated in this connection that at the present day the cobs of the corn used for planting are not burned until rain has fallen on the crop. If the clay spout described really existed among the people at Awatubi, it was likely to have been an innovation introduced by the Spanish missionaries. Among the potsherds picked up at this ruin was a small piece of coarsely made clay tube, which seemed to be too large and too roughly modeled to have been the handle of a ladle, which it roughly resembled, or to have belonged to any other known form of domestic pottery. As a roof drain its use would not accord with the restrictions referred to in the native account, as the piece had been burnt.

In some cases in Zuñi where drains discharge from the roofs of upper terraces directly upon those below, the lower roofs and also the adjoining vertical walls are protected by thin tablets of stone, as shown in Fig. 44. It will be seen that one of these is placed upon the lower roof in such a position that the drainage falls directly upon it. Where the adobe roof covering is left unprotected its destruction by the rain is very rapid, as the showers of the rainy season in these regions, though usually of short duration, are often extremely violent. The force of the torrents is illustrated in the neighboring country. Here small ruts in the surface of the ground are rapidly converted into large arroyos. Frequently ordinary wagon tracks along a bit of valley slope serve as an initial channel to the rapidly accumulating waters and are eaten away in a few weeks so that the road becomes wholly impassable, and must be abandoned for a new one alongside.

Fig. 44. Zuñi roof drain, with splash stones on roof below.

The shiftlessness of the native builders in the use of the more convenient material brings its own penalty during this season in a necessity for constant watchfulness and frequent repairs to keep the houses habitable. One can often see in Zuñi where an inefficient drain or a broken coping has given the water free access to the face of a plastered wall, carrying away all its covering and exposing in a vertical space the jagged stones of the underlying masonry. It is noticeable that much more attention has been paid to protective devices at Zuñi than at Tusayan. This is undoubtedly due to the prevalent use of adobe in the former. This friable material must be protected at all vulnerable points with slabs of stone in order quickly to divert the water and preserve the roofs and walls from destruction.