Flood Mitigation in the Valley

History has shown that no other threat to the Valley of the Queens is more devastating than flash flooding. Although infrequent, a single episode of torrential rains in the valley watershed, such as in November 1994, produces runoff in the magnitude of tens of thousands of cubic meters and transports tons of mud and rock debris from the slopes into unprotected tombs, impacting ancient features and site infrastructure.

Assessment of the flood threat provided the basis for protecting tombs, historic site elements, and modern infrastructure from flash flood. Factors considered were precipitation records and patterns; evidence and records of past flooding; site topography and the rainfall catchment area, subcatchments, and their drainage characteristics; geology, petrology, and susceptibility of the rock to damage as a result of floods; and the location of individual tombs and their flood risk.

Flood control measures must remove water, rock fragments, and sediment rapidly and completely from the site and engineer its safe disposal. It is not sufficient to protect only decorated tombs from entry of water, but shaft tombs, if inundated, act as sumps for the migration of water laterally through the rock joints and fissures into adjacent tombs. Thus, all tombs also require local protection at their entrances as a defense against the intrusion of water.

Detailed planning for flood control was undertaken based on the new topographic map of the valley and a hydrologic study. The map defines the subcatchments and the total catchment area and provides essential information for drainage channels and lines around the tombs. Hydrological modeling for a two-hundred-year flood event predicts the impact of a flood under the current situation and after mitigation measures.

Plans developed for the flood control involve:

• deepening the existing main drainage channel to provide greater capacity for water runoff and sediment flow
• extending the main drainage channel to transport water runoff and debris away from the site and east of the parking area
• diverting upslope runoff away from at-risk tombs on the north and south sides of the valley and into the main drainage channel
• protecting tomb entrances to keep water and sediment out
• protecting the ruins of the Coptic monastery of Deir er-Rumi from upslope runoff