Imperial Irrigation District Sets 2015 Water Apportionment Method

The Imperial Irrigation District (IID) has approved its 2015 water apportionment plan.  On September 23, the IID Board of Directors voted 4-0 (with one member voting absent) to adopt an Equitable Distribution Plan similar to the one used in 2014.  The EDP uses a hybrid formula to determine farmers’ allotments of irrigation water.  50% is determined by a straight-line method, which divides all available water equally on a per-acre basis.  The other half of the allocation is based on the field’s historical water use between 2003 and 2012, discounting the highest and lowest water use years.  If the Board had failed to act by October, apportionment would have reverted to the straight-line method alone, which is the default method.

According to IID, the hybrid method will result in apportionments of between 2.86 and 7.86 acre-feet/acre.  The IID Water Conservation Advisory Board had recommended using identical apportionments from 2014.  While the Board of Directors approved the identical methodology, Assistant Engineer Ben Brock cautioned that it was impossible to guarantee identical apportionment because IID’s total water allocation might be different.

One question mark hanging over the IID as the 2014 apportionment wraps up is whether it will exceed its approved allotment, which would lead the Bureau of Reclamation to reduce its 2015 allotment.  In August, Reclamation sent a letter to IID warning that it was at risk of exceeding its approved share by about 34,000 AF. IID’s water use fell sharply though the fall, putting it on track to consume less than its allotment.  Since November, though, Reclamation’s forecast has showed IID’s projected year-end total steadily increasing, and as of November 12, Reclamation estimated that IID would finish the year with a 1,300 AF overrun.

Written by Stratecon Staff