Utilitarian Drains Theory

America’s Stonehenge has 37 carved grooves, carved basins, ditches, understructure drains, and stone covered drains. (A complete list of these features with photographs and descriptions can be found on the Drains & Basins webpage.) What were their purpose? One possible explanation for these various features is they were for handling rain water during stormy weather. This explanation is a collective consensus which has emerged amongst researchers and writers who have described the site (rather than a formerly proposed theory.) The specifics of the hypothesis are difficult to establish beyond the general thought process that these features were storm water drains. In some cases this interpretation refers to the larger covered and understructures drains while in other cases it is a generalization applied to a larger group of these features. The basic principle of storm water drains has not changed and therefore this analysis will focus on these principles.

Analysis

Storm water drains are designed to collect rain water or melting snow and channel it to a discharge point where the water will not interfere with roads, structures, farm fields, etc. This function is achieved through either intercepting the flow of water prior to it reaching a road or structure, or by draining away water which has pooled or flooded a particular area. These drains need to be sized to handle a large flow of water in a short time period, especially during a summer thunder storm.

Upon initial review only 11 drains meet the basic expectations for storm water drains in terms of size, location, and design. These are all either stone covered or ditch drains. The remaining twenty-six (70%) features are clearly too small to be considered storm water drains. Field observations of the grooved drains during rain storms determined they collected and channeled very little water. Over 99% of the water flows over the surface bedrock unimpeded by any of the grooved drains and basin features. All of the basin features are too small to hold any significant amount of water.

Ditch Drains

Drain feature D29 is an earthen ditch which channels overflow water from an upper wetlands pool to a lower wetlands area. The physical appearance and the zigzag course of the ditch suggest it was a man-made feature rather than a naturally occurring overflow channel. The ditch effectively keeps the water level approximately 6 inches lower than the pool’s embankment.

What is the purpose of this drain? The wetlands pool is located below the summit of the hill and its associated structures. The only structure which could be potentially impacted by the pool flooding is a nearby stone lined open well. Currently, the area around the well is a raised earthen platform with a stone retaining wall. The well is above the flood stage of the pool even without the ditch overflow drain. Therefore there is little to no risk of surface water contamination of the well. The drain serves no discernible practical utilitarian function.

A second earthen ditch drain D27 was dug into accumulated soil on the bedrock. It is located on a level area on the summit of the hill. It has no inlet or outlet. Its location at the summit and in a roughly level area prevents it from collecting water. A storm water drain interpretation can be safely rejected for this feature.

A third earthen ditch feature D31 is located on the southern side of the summit on a gentle slope. This ditch drain cuts across the slope. The quartz stone slab retaining wall is on the uphill slope and rises above the ground level. This creates a barrier to any water moving down slope towards the ditch. This barrier raises serious doubts as to creditability of storm water drain interpretation for this feature.

Stone Covered Drains

The ramp drain D24 is a subterranean stone covered drain extending from the base of the ramp to an exit on the northeastern corner of the ramp’s retaining wall. Its location and size suggest it could be a storm water drain. The drain entrance is currently filled with accumulated humus and it is not operational. Field observations during and after rain storms and winter snow melt have failed to note any pooling of water at the beginning of the ramp despite the clogged drain entrance. The lack of pooling water seems to be the result of the topography of this area. The exposed bedrock in this area is fairly level and therefore does not provide a large surface area for water to be collected and channeled to the drain. Although the ramp is angled downward towards the drain entrance, much of the water is absorbed by the soils of the ramp therefore limiting any runoff reaching the drain.

Stone covered drain D23 is down slope of the ramp drain D24 and is connected to it by a channel in the bedrock. It receives all of its water from the D24 exit and therefore is essentially an extension of it. The D24 analysis is applicable to this drain as well.

The U shaped enclosure structure known as the Pulpit was built on exposed bedrock. The bedrock floor slopes downward towards the interior of the enclosure. The most logical place for a storm water drain would be under the structure’s wall at the lowest point of the slope where rain water would pool. However, the stone covered drain D10 does not drain the interior of the structure. Instead its entry point is half ways down the exterior of the north wall. Water in the drain is directed under the structure and exits at the northeast corner. This serves no practical purpose and fails to drain off water accumulating inside the structure.

Drain D15 is a stone covered drain which is an extension of a large bedrock grooved drain D14. Both drains are in operational condition. Field observations have noted very little water collecting or flowing in this drain system during rain events. This drain system collects surface water from about 400 square feet of bedrock up slope a rather small surface area. This accounts for the lack of significant water flow in the drain.

Drain D17 is a subterranean stone covered drain with adjacent paved walkway. It ends at a stone line sump pit. The drain entrance is inside a sunken enclosure generally referred to as the Sunken Courtyard. Archaeological excavations by Frank Glynn suggest the drain and paved walkway predate the sunken courtyard, chamber, and terraforming in this area.

Researchers are in general agreement that the enclosure’s walls of the sunken courtyard were utilized by Jonathan Pattee for his house foundation (1825-1849) and that a non-interconnecting stone wall was added in the center of the enclosure for additional support of the house. This has raised the question as to whether the drain was related to the house foundation.

With a house foundation there are two approaches to storm water management. The first and most effective option is divert the water away from the foundation. The second less efficient approach is to drain away any water which accumulates inside the foundation. There is no evidence of any exterior diversionary drainage (with the possible exception of D14 & D15 drains up slope) leaving only the second option to analyze. The drain entrance is located at the lower (but not lowest) end of the sloping bedrock. It is located on the side rather than the middle. It would drain some but not all of the water from the cellar. A certain amount of water would pass to the right of the drain and pool in lowest section at the eastern end of the enclosure. The non-interconnected wall in the center of the enclosure creates a barrier to water flowing down slope and there are no drain holes at the base of the wall. Water would eventually seep through the dry mason wall but it ran the risk of water pooling behind the wall during significant rainfall.

This drain ends at one of the two sump pits features found at the site. Sump pits in drain systems are used either to precipitate out sands and other debris from the storm water or designed to allow the water to absorb into the ground. The two sump pits at this site could only hold at best a few gallons of water. Both pits would have been overwhelmed within minutes during a typical summer storm. Neither of the pits were designed to handle a large amount of water at any given time.

If this drain was intended as a storm water drain, it was poorly designed. The foundation was not designed for rapid removal of water and the drain was not properly situated to drain off all the water. The presence of a carefully constructed paved walkway along the length of the lower section is out of character with a storm drain. Finally, the low volume capacity of the sump pit is evidence this drain served a significantly different function.

In the interior of the east wing of the Oracle Chamber is the entrance to a stone covered drain D22. The drain extends down slope with several angle changes in its course and ends at a stone lined sump pit. The drain entrance is located at the lowest point of the chamber which is a logical place for a storm water drain. The bedrock floor inside the east wing has a constantly damp surface most likely from condensation. This dampness has necessitated the installation of a wooden slatted floor to prevent visitors from slipping. Several years of observations of the interior of the chamber during & after rain storms and during spring snow melt have failed to observe any real increase of water on the floor. (In heavy rain events some rain comes in through a small roof opening which is left open year round, the louver stones having been removed.) Although the floor is damp, there is no observable flow of water. The drain does nothing to alleviate the problem of dampness. The observations indicate there is no need for a storm water drain at this location.  The atypical multi-angled course of the drain and the small low volume sump pit raise additional objections to a storm water drain interpretation.

Drain D21 which is a stone covered drain situated in the alcove of the Oracle Chamber is the only drain on site which meets all of the expected criteria for a storm water drain. It is situated at the lowest slope of the bedrock in the alcove and would in theory drain off any water before it flooded into the chamber.

Conclusion

This analysis has found only one of the eleven stone covered and ditch drains at the site meets the expected criteria for the design and placement of storm water drains. With the other ten stone covered and ditch drains there is physical evidence and/or observational data which is contrary to the expectations for storm water drains. The other twenty-six features are simply too small to even be considered storm water drains. A storm water drain hypothesis is not supported by the evidence.