Paso Basin Aerial Groundwater Mapping Pilot Study
Our community needs a more complete picture of our groundwater resources so that we can make better decisions about managing water into the future. The County of San Luis Obispo was fortunate enough to be among three agencies selected for a pilot study to collect groundwater data in a portion of the Paso Robles Basin (click for map of study area). This pilot study is using innovative technology that could change the way that California collects information about groundwater basins.
What would normally take the County years to survey will only take a few days thanks to new aerial groundwater mapping technology called Aerial Electromagnetic method (AEM).
Project Status Update
On November 7, 2019, the groundwater mapping survey over the Paso Basin was successfully completed. Draft survey reports will be added to the table below as they become available.
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Report
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Description
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Link
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Hydrogeologic Conceptual Model in Paso Robles, Traditional HCM Report
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This report was prepared to improve the understanding of the hydrology in the central portion of the Paso Robles Basin based on geophysical data collected in November 2019.
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Click here to view the report |
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October 2020: Draft Data Report SkyTEM Survey, Paso Robles Basin by SkyTEM Airborne Surveys Worldwide
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This report covers data acquisition, technical specifications, data processing and presentation of the SkyTEM312M survey flown in November 2019 in the Paso Robles Basin, CA.
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Click here to view the report
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| Multipoint Statistical Report: Application of a multipoint method to assess potential recharge areas in San Luis Obispo County, California, U.S.A. |
The MPS report discusses the application of a multipoint statistics method to assess potential recharge areas in Pilot Study area in the Paso Robles Basin. |
Click here to view this report |
DWR's Upcoming AEM Surveys
The California Department of Water Resources (DWR), together with Ramboll, GEI, Sinton Helicopters and SkyTEM, will conduct airborne electromagnetic (AEM) geophysical surveys in the Salinas Valley, Paso Robles, and Cuyama Valley groundwater basins, as well as limited portions of the Atascadero Basin and Adelaida Area. These surveys, which will begin in mid-July, will help improve understanding of groundwater resources and support local management efforts in their goals to implement the Sustainable Groundwater Management Act (SGMA).
Watch this short video (https://youtu.be/bT4jBVilTvU) to learn more about the AEM geophysical method, or visit DWR's AEM project webpage: https://bit.ly/36iM3Wo
Got questions? Please email DWR at [email protected]
Recent Informational Presentations
Paso Basin Cooperative Committee Meeting - April 28, 2021 @ 4:00 p.m.
Agenda item 7 - Receive presentation on Paso Basin Aerial Groundwater Mapping Pilot Study
- Click here to view the agenda, staff report, and instructions to participate in the virtual meeting
County Board of Supervisors Meeting - April 20, 2021 @ 9:00 a.m.
Agenda item 35 - Receive and file a presentation of the Paso Basin Aerial Groundwater Mapping Pilot Study
- Click here to view the staff report and supporting documents
- Click here to view the agenda and instructions to participate in the virtual meeting
Technology Flight Demonstration
The County recently held a question and answer session and flight demonstration for the public. To view local news coverage of the event, click here!
Pilot Study Goals
The goal of the pilot study is to acquire survey data to help us make better informed decisions about managing our groundwater resources. Survey data is collected using aerial groundwater mapping technology to characterize and map out the layers and extent of clays, silts, sands, and gravels to a depth of approximately 1000 to 1400 feet below the ground surface. Existing well data will be used to verify the survey results. This pilot study will enhance Sustainable Management Groundwater Act (SGMA) related groundwater modeling and provide a better picture of our groundwater system.
The video above provides an overview of AEM technology and demonstrates how this type of groundwater mapping technology is used. (Video: Stanford University)
Click on the link above to view archived news and study announcements.
Frequently Asked Questions
The Paso Basin Pilot Study will use aerial groundwater mapping technology to characterize the subsurface geology and better understand where groundwater occurs and flows, which is necessary for the refinement of the hydrogeologic model of the Paso Basin.
Instruments attached to a low flying helicopter (~100 feet above the ground surface) towing a large hoop will transmit a weak electromagnetic field. This field interacts with the ground, and the response from the ground is measured using a set of receiver coils attached to the hoop. The helicopter flies back and forth along regularly spaced lines and will cover a distance of of approximately 497 miles. The instrument can collect data to a depth of about 1400 feet below ground. Once combined and calibrated with well data and existing knowledge of the subsurface conditions, this dataset can be used to map out the layering of “course” materials (sand and gravel), “fine” materials (silts and clay) and bedrock to show the structure of the basin and groundwater system. This new knowledge will help guide placement of new monitoring wells or identification of recharge locations.
The map below shows the general area of the flight paths where data will be surveyed, approximately 497 line-miles (800 kilometers) over the Paso Basin. The study will take place in two areas of the Paso Robles Basin, on the east side of the valley, and the area near Highway 46 and Highway 229 by Creston and Whitley Gardens. The helicopter will fly in and out of the Paso Robles Municipal Airport for refueling between production flights.
Is it Safe?
This project does not pose a risk to health or safety. The very low level of magnetic exposure is about the same as standing one foot from a toaster, as shown on the Figure below [see note 1].
The AEM transmitter generates a magnetic field that is lower than 1/100th of the accepted general public exposure level across all frequencies [see note 2].
The same AEM surveys have been conducted in other location throughout California with no reported ill effects to humans or animals.
Notes:
[1] Long Island Power Authority: https://www.lipower.org/
[2] International Commission on Non-Ionizing Radiation Protection. "Guidelines for limiting exposure to time-varying electric and magnetic fields (1 Hz to 100 kHz)." Health physics 99.6 (2010): 818-836.
The State of California signed a landmark agreement to form a partnership with the Kingdom of Denmark to share the latest technology, research, and techniques for water resources management. This Pilot Study presents an opportunity for our community to benefit from this partnership by obtaining a better understanding of our groundwater system.
Project Leads:
- Stanford University
- California Department of Water Resources
- Kingdom of Denmark
Other Partners:
- San Luis Obispo County
- Butte County
- Indian Wells Valley County
Funding Sources:
- California Department of Water Resources
- State Water Resources Control Board
- Kingdom of Denmark
- Project Partners
In 2017, Stanford University Professor Rosemary Knight spearheaded a project to map underground freshwater resources and forecast the intrusion of saltwater into aquifers beneath the California coastal town of Marina. An overview of this project, which was a collaboration between Stanford, the Marina Coastal Water District, and Aqua Geo Frameworks, can be seen in the video at the top of this page.
Other California locations where AEM studies have been completed:
- Marina Coast Water District
- Tulare Irrigation District
- Kawaeh Sub-basin
- Santa Cruz Mid-County Groundwater Agency
- Butte County Indian
- Wells Valley
For questions or additional information, please contact:
Cathy Martin, Water Resources Engineer
County San Luis Obispo Department of Public Works
Email: [email protected]
Phone: (805) 781-5275
Mailing address:
County Government Center, Room 206
San Luis Obispo, CA 93408
Contact Public Works via web form, email, or call us at (805) 781-5252.