Discussion of "SWAT-Based Evapotranspirative Water Conservation Analysis Performed on Irrigated Croplands to Determine Potential Regional Water

1. Under the subheading “Modeling Platform” on page 457, the author has mentioned about using Priestly-Taylor method for computation of potential evapotranspiration (PET). At the same time, the author stated about Penman-Monteith equation for data quality evaluation of evapotranspiration in the subheading “Regional Irrigation Deficit” on page 458. These statements seem to be contradictory. Clarification about the methodology considered in this study is required. 2. The method used to estimate potential evapotranspiration was either the Priestly-Taylor method or the Penman-Monteith equation, which is an empirical method. It is well known that use of this empirical method in different areas yields different results and these methods are fitted to specific regions due to climatic variables (Xu and Singh 2002). Therefore, the evapotranspiration equation needs more scrutiny to determine an empirical method that fits better in the San Miguel Creek watershed, Texas. To obtain accurate values of evapotranspiration, perhaps additional work such as use of lysimeters are needed. The comparison of results of evapotranspiration measured by lysimeters and results employing various empirical methods (including Penman-Monteith and Priestly-Taylor method, among others) are assisted by using the best possible method to estimate evapotranspiration. On the other hand, the estimated evapotranspiration equation which is closer to lysimeter measurements is the best equation. Moreover, author has not provided essential details of either PriestlyTaylor method/Penman-Monteith equation in this study. 3. The author stated “Typical San Miguel flows observed at Tilden, Texas (USGS gauge 08206700), ranged from 0.17 (December) to 8.7 (July) m 3 =s during the 10-year study” on page 457. It seems to discussers that only one gauge station