Assessing groundwater usage for irrigation based on statistics of meter readings

Abstract

【Objectives】 Irrigation for agricultural production in most regions of the world relies on groundwater. Understanding groundwater extracted for irrigation in a region is hence important for water resource management but challenging at regional and catchment scales. In this paper we propose a method to estimate groundwater usage for irrigation. 【Method】 We take Tangshan in Northern China as an example. Based on the number and distribution of boreholes, field investigation in selected areas, planting structures, precipitation, as well as statistical yearbook, we established the relationship between precipitation and irrigation amount, and evaluated the actual groundwater usage for irrigation in 2010 in the studied region. 【Result】 ①The relationship between irrigation amount (y) and precipitation (x) in irrigated croplands and paddy fields was y=1.167×107x-1.277 3 and y=378 796x-0.636 6, respectively, with R2 of the former and the latter being 0.899 0 and 0.883 3. ②The irrigation amount for paddy fields in 2010 varied from 5 763 to 7 649 m3/hm2, larger than the irrigation amount for greenhouses (4 950 m3/hm2) and the irrigated cropland which varied from 2 633 to 4 647 m3/hm2. ③The estimated groundwater extracted for irrigation in 2010 was 1.308 billion m3, differing by 9.42% from that reported in the water resources bulletin. 【Conclusion】 The irrigation amount for paddy fields is larger than that for greenhouse and irrigated cropland. Statistics yearbook can be used with other data to estimate groundwater extraction for irrigation; our analysis showed that the results estimated using this method agree reasonably well with measured data.

Keywords

• agricultural water consumption
• groundwater volume assessment
• irrigation quota
• precipitation
• relationship curve between precipitation and irrigation quota