AEG Sacto March Meeting: Jim Bailey 

Migrating Mud Pot - Emergency Responses to Protect Critical Transportation Infrastructure

Jim Bailey, L.Hg (WA, ID)

 Shannon & Wilson

jsb@shanwil.com

Abstract

The Salton Sea located in southern California, is the southern terminus for the San Andreas fault and a locale for sediment hosted, low temperature geothermal features.  Commonly known as mud pots, these features are believed to form in this area by decarbonation reactions involving sedimentary carbonate that generate carbon dioxide (CO₂) gas.  As the gas rises through various water bearing sediments, likely along existing fault lineaments, they pull sediment and water toward the surface. 

In early 2018 one of these mud pots began migrating toward a critical Union Pacific rail line, a fuel pipeline and California Highway 111 paralleling the east side of the Salton Sea.  This was the first time a mud pot had been observed migrating.  The mud pot produces a sediment slurry at approximately 30 to 40 gallons per minute, eroding soils in the direction of the railroad tracks.  As the mud pot got closer to the tracks the railroad took actions to stop or redirect the migration.

Initial actions included multi-method geophysical surveys, dewatering of the mud pot caldera, and installation of a sheet pile wall.  After Imperial County declared an emergency, three deep borings/wells were drilled to depths up to 800 feet deep.  The borings were used to determine the feasibility of depressurizing one or more aquifers that might be contributing to the flow.  Drilling conditions were challenging due to high concentrations of CO₂, H2S, daytime temperatures up to 115⁰ F, and occurrence of high-pressure gas and water. 

In late September of 2018 the mud pot breached the sheet pile wall and UPRR was forced to construct two temporary tracks.  The fuel pipeline was re-routed in early 2019.  The California Department of Transportation took defensive measures in 2019 in anticipation of the Mud pot impacting Highway 111.  As of February 2020, mud pot movement has slowed but still moving in a westerly direction.

Speaker Bio

Jim Bailey has more than 36 years of water supply development and ground water management experience.  His water resource work has focused on municipal water supply including water rights, well design/construction, and evaluation of well performance issues.  He is a nationally recognized expert in the area of well development and rehabilitation, and a frequent speaker at workshops on well performance and rehabilitation throughout the U.S. and Canada.