Study of rainfall for the design of rainwater harvesting system

Abstract

The study was carried out in the “Tierra Brava” farm Credit and Service Cooperative (CCS) Niceto Pérez, located in the southern plain of Pinar del Río; with 22 ha of fruit trees and more than 90 domestic animals, affected by low availability of water resources. With the objective of defining parameters and criteria, according to the hydrological conditions of the region, for the design of a rainwater collection system. In the diagnosis made it was verified that permanent water sources are limited. However, the hydrological characterization over a period of 58 years; showed an average value of 1367 mm; and peaks above the average, with a return or recurrence period of 5 years. On average in one year of every 5 the annual rainfall will be greater than 1543 mm and in 4 years over than 974mm; which ensures available water to be captured. A good fit of the rainfall records was verified; to the Gumbel distribution function with a 95% K-S confidence and R2; of 0.97. As a result, are defined for the system design; nominal gutter´s diameter and downpipes of 100 mm 50 mm respectively; considering an area of 261 m2; what generates driving flows between 0.875 to 1,750 l /s and a volume of 237.4 m3. Store will guarantee water for domestic use to a family of 6 people and water supply for 282 animals, during dry months.