The IVWA region is one of the most heavily irrigated areas in Illinois, accounting for over 30% of all of the irrigation water use in the state. To better account for water withdrawals, the USGS was contracted to develop an approach to estimating water use from center pivot irrigation. Using a formula based on power consumption, a method has been determined to estimate the amount of groundwater used by agricultural irrigation. Working together with the Menard Electric Cooperative, this approach provides an annual total of gallons pumped from the region. The variability in total gallons pumped from one year to the next reflect the differences in the amount and timing of rainfall in the area.
Eneo la IVWA ni moja ya maeneo yenye umwagiliaji mkubwa zaidi katika Illinois, na inawakilisha zaidi ya 30% ya matumizi yote ya maji ya umwagiliaji katika jimbo hilo. Ili kuelezea vizuri uondoaji wa maji, USGS ilikubaliana na kuendeleza mbinu ya kukadiria matumizi ya maji kutoka kwa umwagiliaji wa pivot ya katikati. Kwa kutumia fomula inayotegemea matumizi ya nishati, mbinu imeamuliwa kukadiria kiasi cha maji ya chini ya ardhi yanayotumiwa na umwagiliaji wa kilimo. Kufanya kazi pamoja na Menard Electric Cooperative, mbinu hii hutoa jumla ya kila mwaka ya galoni pumped kutoka mkoa. Tofauti katika jumla ya galoni zilizopigwa kutoka mwaka mmoja hadi mwingine huonyesha tofauti katika kiasi na wakati wa mvua katika eneo hilo.