Flood Control board approves revised drilling plan, raising USGS monitoring‑well contract to $952,763.50

The Mohave County Flood Control District board approved July 21 a revised proposal from Yellow Jacket Well Drilling Services that increases the US Geological Survey monitoring wells project from the originally bid amount to $952,763.50 — an increase of $288,041.50 — to reflect design clarifications. Director Tara Acton told the board the change is necessary because the contractor’s bid assumed smaller‑diameter wells would be inserted inside pre‑drilled larger holes; the actual design requires drilling separate holes near each site location, meaning additional drilling events.

Acton said the USGS will supply equipment for the monitoring installations while the county covers construction costs and site work; the county expects to place fences and security at the well sites. A Stantec engineer on the meeting’s video call said proposed boreholes will be about 1,100 feet deep with a piezometer installed in the same borehole (a shallower monitoring point is also planned inside the larger borehole). The board approved the revised contract and the use of a City of Tucson cooperative contract vehicle for the procurement.

Funding will come from flood control district budgeted funds. Staff said the change was caught before drilling began and the revision preserves the project’s objectives — installing robust, deeper monitoring points to support long‑term aquifer analysis with higher‑frequency USGS instrumentation.