USE OF HYDROLOGIC SIMULATION MODEL TO EVALUATE AND GENERATE GUIDELINE´S IRRIGATION IN SURFACE IRRIGATION SYSTEMS IN NORTHERN MEXICO

The most important method of irrigation worldwide and in Mexico is surface irrigation, also is the most inefficient in water management, with an average Application Efficiency around of 60%. These values have different explanations, in instance that doesn´t exist some method to inflow water measurement into the field or irrigation event, or this is done only with empiric knowledge. In recent years, researchers, worldwide, taking care of this situation generating Surface Irrigation Simulation models, which allow, easily and with lower costs, evaluate designing and operation of irrigation systems. However, such technological advances remain in scientist circle and do not reach users who are making decisions about irrigation, like producers or irrigators. This work shows a methodology that was used to evaluate surface irrigation in 9 sites distributed in 4 counties of Durango State with corn (Zea mays), cotton (Gossypium hirsutum), sorghum (Sorghum vulgare), oat (Avena sativa) and alfalfa (Medicago sativa). The aim was to find actual values of Application Efficiency (Ea), Requirement Efficiency (Er) and Distribution Uniformity (UD) using SIRMOD II. For this purpose, surface irrigation design and operation parameters were determined using direct measurements in field and laboratory. Then the model was used to generate changes in irrigation parameters with the objective to find the unitary inflow (Qu) and Time of Irrigation (Triego) that maximices Ea, Er and UD to obtain an “Irrigation guidelines”. The results of evaluations show a 61% of Ea, with values from 84.14% in “18 de Julio” trail to 29.15% in “La Loma” trail of Ea, for average Er we found an average of 99.8% and average UD of 81.97%. And after doing several simulations we found some alternatives that may improve these irrigation systems, these include reducing Qu to values between 2 and 6 lps m-1 or reduce irrigation time, These actions can increase the general average of these trails in Ea=87.83% and UD= 86.559%, keeping Er=99.786%