Pre-Colombian Jamaica: Caribbean Archeology and Ethnohistory

48 / Chapter 4.
Figure 7. Twenty drainage basins as defined by the National Atlas of Jamaica (1971). Key.
1. Plantain Garden, 2. Morant River, 3. Yallahs, 4. Hope, 5. Rio Cobre, 6. Minho, 7. Gut
River, 8. Black River, 9. Cabarita River, 10. Orange River, 11. Great River, 12. Montego
River, 13. Spot Valley, 14. Martha Brae, 15. Rio Bueno, 16. White River, 17. Pagee River,
18. Wagwater, 19. Rio Grande, 20. Drivers River.
can be seen particularly well in the headwaters of the Rio Cobre. Elsewhere,
where the rivers pass through limestone, the pattern is quite different. The
karstified interior of the island in the center and west literally swallows the water,
which flows for long distances underground, leaving extensive areas on the
surface quite dry. The effect can be clearly seen in places. Thus the Cave River,
on the other side of the watershed north of the Rio Minho, flows east before
disappearing underground for 22 km, and then reappears as the Rio Bueno.
The Hectors River runs west, alternately sinking and rising, before it becomes
the Black River. Groundwater is present in these areas, but it is often at a great
depth, up to 600 m (2,000 ft) beneath the surface.
The Jamaican climate as a whole is described as tropical maritime, modified
by the prevailing NE trade winds and the daily pattern of land/ sea breezes.
Temperatures are high, but vary both diurnally and in accordance with elevation.
The average daily temperature ranges between 27°C (80°F) in the coastal
lowlands and 13°C (56°F) in the Blue Mountains. Detailed meteorological records
have been kept since 1870 (Brennan 1943; Grinsted 1953; Rogers and
Saunders 1963). Three broad zones in terms of precipitation can be discerned.
The region with the heaviest rainfall, > 2,540 mm (> 100 in) per year, is in the
northeast, on the windward slopes of the Blue Mountains, and in the west-