Table 1: Geographical information about the U.S. Virgin Islands. St. Croix
St. Thomas
St. John
U.S.V.I.
Land Area (sq. mi.)
84
32
20
136
Shoreline (miles)
70.3
52.8
49.7
172.8
Tidal/Subtidal Wetlands (sq. mi.)
2.5
2.4
1.1
5.9
Embayments (sq. mi.)
1.5
0.9
0.1
3 Source: U.S.VI.DPNR, 2005
The islands lie in the middle of a mainstream of ocean currents moving from an easterly to westerly direction. These currents have influenced navigation and shipping patterns since the early days of exploration. The North Equatorial current originating in the Canary Islands region turns into the Antilles current and flows northward towards the mainland United States. The South Equatorial current originating in the Gulf of Guinea flows northward from the northern shore of South America as the Guiana current and eventually meets up with the Antilles current to form the Gulf Stream (Dookhan, 1974). The currents have allowed easy access into and out of the West Indies, which, along with the prevailing Northeast Trade winds, allowed European sailing ships to establish trade routes that endured for centuries. The U.S. Virgin Islands occur on two separate insular shelf platforms separated by a 4,000-meter deep ocean trench. St. Thomas and St. John share the same shelf, while St. Croix occurs on a much narrower shelf to the south (CFMC, 2005). The islands of St. John and St. Thomas benefit from their wider and deeper shelf, which permits them to be a major hub for large ocean-going freight vessels and a popular destination for cruise ships. St. Thomas and St. John have very deep bays with narrow entrances, which make for good harbors since they protect vessels from rough seas and high winds (Dookhan, 1974). In contrast, St. Croix has wider bays that are open to rough weather. The U.S. Virgin Islands are located in the belt of the northeast trade winds, which affords them a mild and uniform subtropical climate. High temperatures generally reach 95°F in the summer months while low temperatures reach 67°F in the winter months, with mild seasonal variations. The rainy season runs from September to November. The average annual rainfall is 41 inches per year. Rainfall, unlike temperature, can vary significantly, raising water conservation concerns, particularly in drier years due to a lack of naturally occurring freshwater throughout the islands (Dookhan, 1974).
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