Rio Grande Compact Accounting
“The Rio Grande Compact contains a schedule for water that must be delivered by New Mexico to Elephant Butte Reservoir every year. This schedule is based on a relationship between the amount of water passing the Otowi flow gage in a year, the amount of water released from Elephant Butte Dam, and the change in storage in the reservoir that year (See Article IV of the Rio Grande Compact as modified in 1948).
It is not required that the exact amount of water specified in the Article IV schedule be delivered every year. The compact provides for a debit and credit system whereby deviations from the scheduled deliveries are tracked each year. A credit means more water was delivered than scheduled while a debit means the opposite. There is no limit on accrued credit; however, there are limits on accrued debit as described in Article VI of the Rio Grande Compact.
The engineer advisers to the Rio Grande Compact Commissioners meet during the month of February of each year to review flow records for the previous year, determine the scheduled and actual delivery of water that year, and produce an annual report to the Rio Grande Compact Commission. The U.S. Geological Survey assists the Commission by compiling flow records used in the annual compact accounting and by preparing provisional reports.”