ABSTRACT
The demand for irrigation water is determined generally by the distribution and level of rainfall relative to the location of agricultural land. Other variables besides rainfall, which affect the need for irrigation, are temperature, gradient, elevation, the kind of plants and soil characteristics. There is great variability among each of these factors across Ecuador and consequently a large number of agro-ecologic zones. This suggests that the need for irrigation varies considerably from zone to zone. Rainfall in the Sierra generally is equatorial with a bimodal distribution, peaking in April and again in November. The rainy season starts in October and continues through May with reduced precipitation during July through September. In contrast, the Central and Southern Costa have a tropical pattern of rainfall characterized by a single peak, usually in March. Rainfall begins in December, increases through March and falls off sharply in May.
