Third Pyramid of Seneferu

THIRD PYRAMID OF SENEFERU

2615 BCE

King Seneferu rebuilt and enlarged the step-pyramid complex of Huni at Meidum approximately fifteen years after it had been constructed. As part of the renovation, he transformed the step-pyramid into a smooth-sided (non-stepped), geometrically true pyramid. This was his third pyramid project.

     The ancient title of this pyramid complex is unknown, but it may have been the same title given to Seneferu’s nearby pyramid town called Djed  , which meant Endurance. It was similar to many other titles of the Old Kingdom pyramid complexes, including two of Seneferu’s, which were titled with a single hieroglyphic word (Glorious  ).

When Seneferu rebuilt the earlier step-pyramid, he filled in the steps and formed a smooth surface. Essentially, he covered the outer surface with a new layer of casing stones and gave it the appearance of a geometrically true pyramid. His engineers applied the casing stones over the earlier casing stones on Huni’s step-pyramid, which was a risky construction technique because the earlier casing stones were not a suitable underlay for the new casing stones (the core that is visible today is actually the finished exterior of the step-pyramid of Huni). The lower courses of the casing stones were not capable of supporting the casing stones above, and this eventually caused them to collapse. However, it is evident from the rubble around the base of the pyramid that the collapse was evenly distributed, so it appears that all of the sides fell during a single event, such as an earthquake. An observatory structure was uncovered in the rubble, and it was in excellent condition, so it may have been buried by the collapse before it could be used (the stele were never inscribed). Thus, it is possible that a collapse occurred during the renovation.

     The decision to alter the step-pyramid was based on the realization that rainwater would cascade down the pyramid’s sides more efficiently if there were no steps interfering with its descent. The builders stacked small stone blocks on the steps for support and then covered them with polished limestone casing stones that were mortared together. The new casing stones enlarged the original step-pyramid by about twenty percent to form a new base that was 475 feet square. The new height was 300 feet. The surface of the pyramid had a rain catchment potential of 225, 180 gallons of water per inch of rainfall.

Seneferu paved the bare bedrock that originally formed the floor of the basin with mudbrick and then plastered it. Apparently, he was trying to level out the old basin to help it drain properly. He did not pave the basin with stone blocks. He expanded the size of the original catchment basin and built a new enclosure wall made with large limestone blocks. The older fieldstone wall was removed. The basin was about 150 feet wide, from the pyramid’s base. This was much wider than later catchment basins around pyramids. The extreme width was ideal for harvesting a great amount of rainwater. However, it was inefficient because the water level would have been too shallow, which meant that it would drain very slowly to the aqueduct. This delay could allow some of the water to evaporate or leak. A wide basin was difficult to maintain because it had excessive surface area, which is probably why Seneferu paved it with plaster instead of stone blocks. The expansive basin would have required an enormous amount of stone blocks to create, and an incredible amount of mortar for the joints. Additionally, it would have required extensive  maintenance. It had a rain catchment potential of 84, 750 gallons per inch of rainfall. The width of later catchment basins was less than half the width of the one at this pyramid complex. Nearly all the catchments basins after Seneferu’s reign were paved with polished, fine-grained stone blocks.

     The gate to the aqueduct was located in the center of the eastern enclosure wall. Its remains indicate that it was a stop log water gate that contained wooden planks, which were lowered or raised to determine the speed of the flow of water as it was released to the aqueduct.

  

A small, rectangular structure (30 feet square and 10 feet high) was built against the east face of the pyramid (within the catchment basin). It was made of fine limestone blocks. A stone enclosure wall surrounded the structure on three sides, with the fourth side being formed by the face of the pyramid. It was entered through a stone portal that led to a zigzag hallway, which led to a small open-air courtyard at the foot of the pyramid. There was just enough room inside the courtyard for two large, upright rectangular slabs of fine limestone. They were never inscribed, and this may indicate that they were used as gnomons.

     When it rained on the pyramid, the water cascaded to the courtyard and flooded it. The water then drained through the zigzag corridor and spilled into the catchment basin. As the catchment basin filled with water, the structure was partly submerged. This did not affect the building because it was made entirely of stone. The structure may have functioned as an observatory for the purpose of calculating the seasons as well as determining the timetables for planting crops. It would have been possible to determine the solstice with two gnomons that faced eastward. The stones would have cast their shadows against the smooth surface of the pyramid and they could also be used to tell the time of day. A person could stand under the roof of the structure and make observations of the shadows on the pyramid. The zigzag corridor, which was behind the observer, prevented light from entering the chamber. This helped maintain a cool temperature within the structure. There is a very similar gnomon structure at the second pyramid complex of Seneferu, which was built just prior to this one.

King Huni constructed a satellite pyramid on the south side of the main pyramid prior to the Seneferu’s rebuilding phase. Seneferu incorporated the satellite into the new catchment basin when he redesigned the complex. It was approximately 90 feet square and 55 feet high. It’s purpose was to capture rainwater and store it below its base. The enclosure wall of the new complex was built around it. Presumably, the satellite continued to capture rainwater during light rainstorms.

     

The new aqueduct was one of the first ones constructed entirely out of stone blocks. It was 500 feet long and 10 feet wide. It coursed nearly due east on a channel that was carved directly into the bedrock. The interior channel was 4 feet wide. Its walls were 3 feet wide and 7 feet high. They were constructed with very large limestone blocks. The earlier aqueduct, which had mudbrick sidewalls, was the last one ever built with mudbrick elements (except for Shepseskaf’s) during the Old Kingdom. This is because the aqueduct walls had to be replaced and repaired too often. Stone walls endured much longer in a watery environment. The aqueduct did not contain a roof. When the aqueduct was first excavated, archaeologists discovered that the water channel was layered with mudbrick that had been placed over the stone pavement. This was probably done long after the RCS stopped functioning in order to provide a better surface for pedestrian traffic (when the memorial monument was visited during the New Kingdom). 

White limestone blocks and part of a granite doorway for the WCB were discovered near the banks of the ancient Nile River. Unfortunately, the structure lies below the water table so it cannot be excavated without considerable expense and technology. A long mudbrick wall was discovered near the end of the aqueduct, and this may be part of the enclosure wall of the WCB.  

 

SENEFERU • PLAN OF THIRD PYRAMID COMPLEX