Share

First State Geology Newsletter Signup

First State Geology has been the newsletter of DGS for over 25 years.

Click here to signup!

Site content related to keyword: "benchmarks"

DGS Cooperative and Joint-Funded Programs

The DGS is, by statute, the state agency responsible for entering into agreements with its counterpart federal agencies, including the U.S. Geological Survey, the USGS Office of Minerals Information (formerly the U.S. Bureau of Mines), and the Bureau of Ocean Energy Management, Regulation and Enforcement (formerly the U. S. Minerals Management Service), and for administering all cooperative programs of the State with these agencies. The DGS also works with many in-state and out-of-state partner agencies and organizations.

The Mason-Dixon Line, that land is your land

The Mason-Dixon Line, That Land Is Your Land

The Mason-Dixon Line wasn’t created to divide North and South, but to settle a dispute between Colonial landowners. The Mason-Dixon Line, the iconic dividing line between North and South, is an invisible line running across the backyard of many Delawareans. Charles Mason and Jeremiah Dixon’s milestone markers still dot the Maryland-Delaware-Pennsylvania border more than 240 years after they completed their survey.

OFR17 A Guide to Information on Benchmarks in Delaware

OFR17 A Guide to Information on Benchmarks in Delaware

To conduct an elevation survey, a surveyor needs a starting point for which the exact elevation above mean sea level is known. These starting points are called benchmarks. State and federal agencies install benchmarks throughout every State, creating a network of elevation points which covers the entire continental United States. These benchmarks are considered to be permanent, and usually consist of a brass, bronze, or aluminum disc about 4 inches in diameter mounted in a cement post or in a drill hole in a permanent foundation. Each benchmark also has the installing agency's name and an identification number stamped into it. In December of 1980 the Federal Emergency Management Agency (FEMA) allotted the State of Delaware funds to determine the number and condition of federal benchmarks and other elevation reference control points. The National Flood Insurance Program (NFIP), contained within FEMA, requires accurate flood surveys of property in flood-prone areas. An extensive and accurate benchmark network throughout the State is needed to help meet these needs.