Prediction of Wind Pump Water Discharges for Drip Irrigation at the Shores of Lake Victoria-Kenya

Full Text PDF PDF
Author(s) Kabok .P. Aguko | D.M. Nyaanga | J.O Onyando
Pages 273-284
Volume 3
Issue 5
Date May, 2014
Keywords Instantaneous Discharge Equations, Governing Equations, Resource Equations, Percent Wind Speed Availability, Irrigation duration.
Abstract

Wind pump discharge has traditionally been estimated from the manufacturer’s tables. However for wind pump drip irrigation (WPDI) system there is need to relate the discharge to hydraulics in the pipeline, emitter discharges and weather/soil. The relations in the form of governing equations comprise of the instantaneous discharge, pipe, emitter and resource equations (ETo, area and duration of irrigation). The objective was to predict from the wind speeds the expected discharge and relate it to the governing equations. The actual wind speed and wind pump discharge data from Rusinga was initially used to compare the performance of the existing instantaneous wind pump discharge equations. The Kisumu 10 m wind speeds assisted in developing the percent availability instantaneous wind pump discharge equation(Q=K(∑▒〖V_i R_i)〗which was used to estimate the irrigation depth and area by relating to known irrigation equations. The results showed that the irrigation duration could be predicted from the developed wind speed interval percent availability tables. The discharge equation (model) developed based on availability was in agreement with the results from the existing instantaneous wind pump discharge equations. The accuracy of the equations to predict discharge improved with the length of the hourly wind speed, short time step of measurements, the startup pump rotation speed and the measuring equipment. It was possible to estimate wind pump discharge from hourly wind speeds, wind strength limits thus irrigation area, depth and duration.

< Back to May Issue