Groundwater Basin Mapping Technology

Paso Basin Aerial Groundwater Mapping Pilot Study Using Aerial Electromagnetic Measuring Technique to Map Local Aquifer System

Author: Public Works
Date: 10/31/2019 10:57:09 AM

Paso Robles Basin, October 31, 2019 – The County of San Luis Obispo will conduct the Paso Basin Aerial Groundwater Mapping Study to survey our local aquifer system starting in early to mid-November 2019 for 3 to 5 days.

The study will take place in three areas of the Paso Robles Basin, including areas by Highway 46 near Whitley Gardens, Highway 229 near Creston, and Highway 41 near Shandon. Please see map for specific locations.

Our community overlying the Paso Robles Basin needs a more complete picture of the groundwater basin so better decisions can be made about our water in the future.  In November, residents of Creston, Shandon, and Whitely Gardens may see a low-flying helicopter towing a large hexagonal frame. This technology, called an aerial electromagnetic measuring technique, will map subsurface aquifers in the area in order to improve our understanding of the available groundwater resources. 

During the survey, instruments mounted on a large hexagonal frame will be hanging beneath the helicopter at 100 feet above the ground to collect subsurface data down to 1,500 feet below the land surface. These instruments send a weak electromagnetic signal that interacts with the ground, which in turn sends a signal back to receivers on the frame. Data are continually acquired while the helicopter flies approximately 500-line miles at about 50 miles per hour. The County will use information from the survey in combination with well data to develop a more thorough understanding of the local groundwater system.

This project does not pose a risk to health or safety. The weak magnetic field from the equipment is about the same as if you stood one foot away from a toaster. The helicopter will be avoiding urban areas.

The helicopter will fly in and out of the Paso Robles Municipal Airport for refueling between flights. Experienced pilots, who are specially trained for low-level flying, will be operating the helicopter and following Federal Aviation Administration regulations to ensure flights are in accordance with U.S. law.

For up-to-date project information, including flight dates and mailing list information, please visit: