1. (a) For the purpose of establishing accounts in Amistad and Falcon Reservoirs, the two reservoirs are considered to constitute a single storage system. Accounts in the Lower and Middle Rio Grande are based upon a water right's annual authorization in acre-feet. Water rights for irrigation and mining purposes are considered as having irrigation priority rights and therefore are included in the irrigation accounting system.

2. (b) When there is adequate water to do so, the watermaster shall maintain the following accounts:

   1. (1) a reserve of 225,000 acre-feet of water for domestic, municipal and industrial uses;
   2. (2) an operating reserve which is to fluctuate between 380,000 acre-feet and 275, 000 acre-feet of water based on the monthly levels of the Amistad-Falcon Reservoir system;
   3. (3) the accounts for irrigation uses and all other uses.
3. (c) The operating reserve is to be calculated monthly by multiplying the percentage of total U.S. conservation storage capacity in the system times the maximum operating reserve of 380,000 acre-feet. The calculated reserve cannot be less than 275,000 acre-feet of water, except as provided by §303.22(e) of this title (relating to Allocations to Accounts). The operating reserve is necessary to provide for loss of water by seepage, evaporation, and conveyance; emergency requirements; and adjustments of amounts in storage as may be necessary by finalization of provisional computations by the International Boundary and Water Commission.

Source Note:The provisions of this §303.21 adopted to be effective July 2, 1986, 11 TexReg 2890.