Estimating Actual Evapotranspiration Using the Metric Model and Comparing it to In-Situ Hydrological Measurements in an Irrigated Catchment

DOI

10.2991/978-94-6239-666-1_15How to use a DOI?

Keywords

Actual Evapotranspiration; METRIC-ETa; Remote Sensing; Water Balance

Abstract

Accurate estimation of actual evapotranspiration (ETa) is crucial for enhancing water use efficiency in large-scale irrigation networks. Furthermore, quantifying elements of the basin-scale water budget is crucial for assessing variations in water components and identifying potential deficits or surpluses. This study examines the results of hydrological research acquired during the 2023 water year in the Akarsu irrigation scheme, which covers 9,495 hectares in the Lower Seyhan Plain (LSP) of the Eastern Mediterranean Region of Türkiye. The objectives were to: (1) measure water inflows and outflows at key points in order to calculate the components of the basin-scale water balance; (2) estimate ETa using the METRIC model and comparing it with crop evapotranspiration (ETc) derived from the two-step crop coefficient (Kc) method; and (3) assess water balance closure errors using ETa and ETc estimates. To estimate ETa at a spatial resolution of 30 × 30 metres, a total of 20 Landsat images (from Landsat 7, 8, and 9) were used, along with meteorological data from two local stations. Daily measurements of net irrigation inflow and drainage outflow were collected throughout the study period. The total ETa was estimated to be 914.1 mm in the 2023 water year, with a net irrigation input (Inet) of 1,852.3 mm, a precipitation (P) input of 543.6 mm, and a net drainage outflow (Qnet) of 840.6 mm. These inputs resulted in a net water storage change (ΔW) of +642.2 mm. Using ETa in water balance calculations yielded minor closure errors compared to those based on ETc estimates. These findings demonstrate that satellite-derived ETa provides a more accurate representation of actual water consumption, thereby improving the precision of hydrological assessments. Consequently, integrating remote sensing into irrigation water management practices has great potential to support precision agriculture at the basin scale.

Copyright

© 2026 The Author(s)

Open Access

Open Access This chapter is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

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TY  - CONF
AU  - Mahmut Cetin
AU  - Halil Karahan
AU  - Muhammet Said Golpinar
AU  - Omar Alsenjar
AU  - Muge Erkan Can
PY  - 2026
DA  - 2026/05/07
TI  - Estimating Actual Evapotranspiration Using the Metric Model and Comparing it to In-Situ Hydrological Measurements in an Irrigated Catchment
BT  - Proceedings of the 5th International Conference on Research of Agricultural and Food Technologies (I-CRAFT 2025)
PB  - Atlantis Press
SP  - 153
EP  - 163
SN  - 3005-155X
UR  - https://doi.org/10.2991/978-94-6239-666-1_15
DO  - 10.2991/978-94-6239-666-1_15
ID  - Cetin2026
ER  -