river canyons on Continental Slope, submerged about 12-15,000 years ago
Source: National Oceanagraphic and Atmospheric Administration (NOAA), Estuarine Bathymetric Data
When the first Virginian's arrived perhaps 11,500-15,000 years ago, sea levels were 300-400 feet lower because so much water was locked up in the glaciers and continental ice sheets. The Coastal Plain of Virginia extended much further to the east, where sloping hills and cliffs marked the edge of the land and ocean. The James and Susquehanna rivers carved separate valleys across the wide Coastal Plain to the salt water, and there was no Chesapeake Bay.
Much of the Coastal Plain has been drowned by the rising Atlantic Ocean since then, creating the Outer Continental Shelf between the Atlantic Ocean shoreline and the cliffs of the Continental Slope. The ancient river valleys of the Susquehanna and James rivers remain as underwater canyons. Those driving across the Chesapeake Bay Bridge-Tunnel dip underwater at two locations shaped by those rivers, in a tunnel under the James River channel (Thimble Shoals) and further north under the old path of the Susquehanna River (Chesapeake Channel).
By the time Europeans arrived in Virginia, the Atlantic Ocean coastline was marked by marshes and barrier islands on the Eastern Shore and wide sandy beaches south of the Chesapeake Bay. Sea level is still rising, but the outline of the Chesapeake Bay and the extent of the Outer Continental Shelf has changed only slightly in the last 500 years.
The development of submarines, starting in World War I, increased interest in mapping the topography of the seafloor. Developing the mineral resources below the ocean became technologically feasible in the middle of the 20th Century, greatly increasing interest in the continental shelf. Onshore oil fields extended offshore, and oil companies sought to build platforms for offshore oil wells. Starting in 1937 state/Federal governments debated what level of government was authorized to grant drilling permits and collect royalties. In 1947, the Supreme Court ruled that the Federal government could control development of offshore mineral resources. The decision established that soveriegn rights over the seabed and ocean were acquired by the national government when it replaced the power of the king/Parliament after the American Revolution, and not by the colonial governments through their original charters from the king.1
Congress passed the Submerged Lands Act in 1953, granting states control over the bottom of the ocean for three miles offshore (9 miles for Texas and the west coast of Florida). The law also confirmed state ownership of "all lands permanently or periodically covered by tidal waters up to but not above the line of mean high tide." The three miles offshore was measured from the "line of ordinary low water along that portion of the coast which is in direct contact with the open sea."2
More legal wrangling was required after 1953 to clarify the relative power of the states/Federal government over the Outer Continental Shelf. In United States v. Maine, Virginia claimed that its colonial charters granted the state exclusive jurisdiction of Atlantic Ocean resources for 100 miles beyond the coastline.3 The US Supreme Court rejected that claim in 1975.
Virginia law authorizes private landowners to control land down to the mean low-water mark.4 However, the Virginia Marine Resources Commission regulates filling of tidal wetlands from "low tide inland to a point 1.5 times the mean tide range."5
In 1953 Congress passed the Outer Continental Shelf Land Act, endorsing the national government's claim to the ocean resources issued originally by President Harry Truman. International claims of rights to control navigation, fishing, and economic development of mineral resources led to the United Nations Convention on the Law of the Sea. Congress has never ratified that treaty, in part due to potential international controls on deep sea mining of polymetallic (manganese) nodules in the Pacific Ocean.
Consistent with the treaty, the United States has claimed a Territorial Sea for 12 miles offshore, plus an Exclusive Economic Zone (EEZ) extending from 12-200 nautical miles offshore. Based on that claim, Federal agencies will determine if windmills and oil drilling platforms will be permitted on the Outer Continental Shelf, while state agencies will manage the inner continental shelf within three miles of the shoreline.
The United States is considering extending its claim beyond the 200 nautical mile limit, to encompass the entire Outer Continental Shelf. Article 76 of the United Nations Convention on the Law of the Sea would allow extending American claims from 200 nautical miles to as much as 350 nautical miles east of the shoreline, based on the location of the foot (bottom) of the Continental Slope. Most effort is focused now on defining the edge of the continental shelf in the Arctic Ocean, as the basis for clarifying boundaries between Russia, Canada, and the US, but the US government is exploring the potential for an extension of the EEZ in the Atlantic as well.
boundaries of the Outer Continental Shelf may not extend beyond "constraint lines" defined by the Convention on the Law of the Sea
Source: Extended Continental Shelf Project
Off the coast of Virginia, the state controls fishing and mining for three miles. To manage fishing within the three mile limit, 15 Atlantic Coast states have partnered to create the Mid-Atlantic Fishery Management Council. Between 3-200 miles, the Federal government is responsible. The National Marine Fisheries Service, part of National Oceanographic and Atmospheric Agency (NOAA), manages fishing limits and ensures compliance in the Exclusive Economic Zone (EEZ) outside of state waters.
Offshore oil and gas resources (including gas hydrates) in the Federal portion of the EEZ have generated great interest. The Bureau of Ocean Energy Management, Regulation, and Enforcement (called the Minerals Management Service - MMS until after the Gulf of Mexico oil spill in 2010) prepares a 5-year schedule of oil and gas lease sales.
A Federal moratorium on leasing off the Atlantic Coast was not renewed by Congress in 2009, and the Obama Administration scheduled the sale of an oil and gas lease off Virginia. However, that sale was cancelled after the BP well blowout in Gulf of Mexico.
In the long term, offshore sediments may be mined for heavy metals such as titanium. High percentages of ilmenite, a titanium-rich mineral, has been found in samples off the coast of Virginia. For the moment, however, the most valuable offshore mineral resource being utilized is sand. Beach replenishment projects for Sandbridge rely upon Federal offshore sand, mined from locations beyond the 3-mile boundary.
