Confined Aquifer Confined Aquifer: In the hydrogeology branch of geology, a confined aquifer is an aquifer that is overlain (and underlain) by a layer of low permeability, such as clay, shale, or silty clay. In fact, the two confining layers contain the storage and flow of groundwater, such that the aquifer maintains hydraulic pressure (or…

Design Methane Pressure (Soil Formation Pressure) Design Methane Pressure or Soil Formation Pressure: As per the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, Design Methane Pressure means the highest observed measurement of soil formation pressure during the methane testing process. In fact, a Design Methane Pressure measurement that is…

Perforated Horizontal Pipe in Methane Mitigation Perforated Horizontal Pipe: As per the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, a perforated horizontal pipe is a PVC or ABS pipe that contains a series of small holes or narrow openings placed equidistantly along the length of the pipe, and is…

De-Watering System in Methane Mitigation De-Watering: In accordance with the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, a de-watering system is a permanent water removal system in a methane mitigation system. In the mitigation process, a de-watering system consists of perforated horizontal pipes, gravel pockets, sump areas with pumps,…

Rotational Slide (Slump) Definition Rotational Slide (Slump):  A rotational slide is a type of landslide movement that occurs in a turning moment, about a pivot point that is above the center of gravity. This is typically due to an increased normal force on a slope, as well as a reduced cohesion factor of the soil…

Licensed Professional Geologist A “Licensed Professional Geologist” or a “Certified Professional Geologist” is a person who is certified by a State and/or Federal agency (such as the California Department of Consumer Affairs, Board for Professional Engineers, Geologists & Land Surveyors), and has proven be educated, formally trained and professionally competent per government standards, to practice…