The Vamori Wash Levee Project was a flood control design project located in Pima County near the Tohono O’odham village of Vamori on the Tohono O’odham Nation.  This project was included in this SOQ to demonstrate the variety of capabilities which ConformaTech offers the County as well as an example of Key Team Member/subconsultant collaboration and completion of the project within cost estimates.

The Vamori Wash project has a 100-year flood event design flow volume approximately equivalent to the Rillito River in the Tucson area.  Multiple times, storm water flows have overflowed the main wash and caused significant flooding within the village of Vamori, approximately two miles west of the wash.  This project included a 2019 hydrology study of the flood plain and design of an earthen flood control levee.  The project has not yet gone under construction.

The proposed levee will be approximately 2,000 feet long and approximately nine feet in height. The design flood elevation is approximately three feet below the crest of the proposed levee.  The levee will be an earthen embankment, and we expect the crest will be approximately eight feet wide and the side slopes will have inclinations of approximately three to one (horizontal to vertical).  The levee will be constructed on the west side of the Vamori Wash just south of Indian Route 2.  The north (downstream) end of the levee will likely have some form of erosion protection (e.g. hand-placed riprap).

ConformaTech’s role on the project was as the geotechnical engineering subconsultant to the hydrology design firm, JE Fuller.  Our geotechnical work included evaluations of embankment stability, settlement and seepage and development of construction and materials specifications for levee construction.

Challenges posed by the project included confining the construction limits to an area outside the heavily vegetated main wash channel and limiting disturbance to the adjacent pasture lands between the wash and the village.  Much of the material proposed for levee construction is planned to be sourced from borrow areas from within the Tohono O’odham nation, and ConformaTech has been involved with follow-up work through 2020 in identifying potential suitable borrow sites.  The above considerations, as well as close communication with the design team and Tribe, resulted in design parameters which minimize cost and environmental/cultural impacts.  The fee of ConformaTech’s services for this project were proposed and completed within the lump sum fee of $9,600.00.