text: Chapter 7
  provided water and other supplies. While most islands are natural, formed by tectonic or volcanic action,
  manmade islands created for military and other purposes are also found within certain regions, such as the
  South China Sea. Maritime land masses include a variety of environmental conditions. Islands throughout
  Southeast Asia are predominantly jungle and savanna regions. Islands throughout the Baltic, Arctic, and sub-
  Arctic regions may experience prolonged periods of extreme cold weather. Mountainous terrain can be found
  on jungle, Arctic, and desert islands. Each island can contain unique environmental planning considerations
  that can affect the way Army forces are resourced and employed. (See ATP 3-90.97 for more information on
  cold weather environments. See ATP 3-90.98 for more information on operations in jungle environments.
  See ATP 3-90.99 for more information on operations in desert environments.)
  7-3. Currently, 22 nations in the world are recognized as archipelagic states, and these unique maritime
  nations can include several cultures, religions, languages, and geopolitical histories within their own
  territorial boundaries. Regional influences, littoral urbanization, external actors, regional geopolitical
  perspectives, and local economic conditions may change from island to island, even when those islands
  comprise a single country. Commanders and staffs must understand these complex factors to influence
  outcomes in the human and information dimensions of an operational environment. Corps, divisions, or even
  brigades may have an area of operations (AO) that spans several islands, each with a unique culture and
  history.
  7-4. In a predominantly maritime environment, any land that can be occupied to attain a physical position
  of relative advantage by friendly or enemy forces can become key terrain. The largely maritime domains
  challenge planners to account for operational reach and the impact of space and time on reinforcement of
  existing forward-stationed forces and allies. The distance between bases throughout the maritime regions
  hinders mutually supporting operations and sustainment from supporting echelons in the theater. Remoteness
  and distance increases vulnerability to amphibious raids by enemy special operations forces and attacks from
  long-range aircraft or missiles, and it increases the risk of physical isolation by air and naval forces.
  LITTORAL REGIONS
  7-5. Maritime environments include littoral regions, divided into two segments: seaward and landward.
  Seaward segments include the area from open ocean to the shore, which must be controlled to support
  operations ashore. Landward segments are those areas inland from the shore that can be supported and
  defended directly from the sea. Maritime littoral regions are divided into five categories:
  (cid:122) Enclosed and semi-enclosed seas—bodies of water surrounded by a landmass and connected to
  either an ocean or another enclosed sea by a connecting body of water, such as a strait.
  (cid:122) Islands—single land masses surrounded by a body of water.
  (cid:122) Archipelagoes—groups of islands.
  (cid:122) Open seas—unenclosed bodies of water, typically outside of territorial boundaries.
  (cid:122) Marginal seas—portions of open seas or oceans that bound land masses such as peninsulas,
  islands, and archipelagos.
  7-6. Operations in these environments require information concerning tides in the local area, average wave
  heights, and daily wind forecasts, as tides and winds may unexpectedly impact wave heights. Tidal flow and
  currents impact operations for small or shallow draft vessels. Tidal changes can also affect vehicle mobility
  when crossing unimproved beachheads or operations without causeways or engineer support. Extreme
  weather plus the corrosive effects of salt water can rapidly degrade the maintenance readiness of equipment
  already at the extent of long logistics lines of communications.
  ARCTIC REGION
  7-7. The Arctic region is significantly influenced by maritime considerations. The Artic encompasses part
  of the areas of responsibility of three different geographic combatant commands, eight countries, and all time
  zones. There are two primary transit routes through the Arctic: the Northwest Passage and the Northern Sea
  Route. The Arctic is a geopolitically competitive region and a potential area for armed conflict. There are
  various international partnerships and alliances within the region, with overlapping relationships complicated
  by international disputes about maritime boundaries. The Arctic presents a harsh and demanding maritime,
  land, and air environment for military operations. Extreme temperatures, long periods of darkness and