Trench Dam: Per the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, a trench dam is part of a methane mitigation system. A trench dam is essentially a subsurface barrier that exists within a furrow or ditch, that is adjacent to the foundation of a building in a methane zone or methane buffer zone. And the purpose of a trench dam is to prevent the migration of methane soil gas through any permeations of a building foundation.
Plat Map Definition Plat Map: A plat map provides the metes and bounds of a parcel in a large tract (to scale), as well as the legal land-use rights and limitations. Additionally, it demonstrates locations of streets and public utility easements, as well as ingress and egress easements. And sometimes plat maps provide information about…
Troposphere Troposphere: The troposphere of a terrestrial planet is the lowest member of the atmosphere. On Earth, the troposphere starts atop the ground surface and terminates roughly 10 kilometers above mean sea level. In fact, geologists understand that most of the Earth’s water vapor (clouds) exists in the troposphere. And the next member of the…
Sedimentary Rock Definition In geology, the term “Sedimentary Rock” refers to the classification of rock that is the result of the gradual consolidation and deposition of loose particles of other rock classifications (igneous or metamorphic). Alternatively, sedimentary rocks can also form by the accumulation and precipitation of other natural chemical solutions in a depositional environment….
Mafic Definition In geology, “mafic” is a term that describes an igneous rock that has an abundance of darker color minerals.
Degree of Saturation (SR) “Degree of Saturation” (SR) is an engineering geology term and refers to the ratio of the volume of water to the total volume of void space. The Degree of Saturation or SR-value ranges from 0% to 100% (0% being completely dry, and 100% being fully saturated). Degree of Saturation Formula Degree…
Gravel Blanket in Methane Mitigation A gravel blanket is a 2-inch or 4-inch thick layer of gravel, sand, or approved material that transmits methane soil gas to the horizontal sub-slab perforated pipes and verticle vent riser of a passive methane mitigation system.
