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Re-distribute Reservoir Contents

Certain reservoirs do not allow carry-over of storage water in users’ accounts from one year to the next; they have provisions that require they re-distribute the total reservoir content pro-rata to each account prior to beginning the next “release season”. For these reservoirs, bookover operating rules are used to simulate these operations by re-distributing the reservoir contents in a specific month.

  • In the reservoir station file (*.res), create an additional “bookover” account in the reservoir that is equal to the sum of the accounts’ capacities that will be re-distributed; often this is the full capacity of the reservoir. Set evaporation for the bookover account to zero.
  • In the reservoir right file (*.rer), set the storage rights to only fill the active accounts in the reservoir, not the bookover account.
  • Include bookover operating rules (Type 6) in the operating rule file (*.opr) that individually book the active accounts into the bookover account. Use monthly switches and appropriate priorities to control when the bookover occurs.
  • At a priority just junior to the step above, include a “re-distribution” bookover operating rule (Type 6) that distributes the contents of the bookover account back to the individual user accounts based on the ratio of the account capacity compared to the full capacity.
  • To prevent StateMod from re-operating the bookover in a single time step, which causes inflated bookover amounts in model output, include the “re-distribution” Type 6 operating rule ID in the initial bookover operating rules to stop the re-operation once the “re-distribution” operating rule triggers. See additional discussion on this functionality using the ciopso(2) and OprLimit flags in the Type 6 operating rule in Section 4.13.6.
  • Re-distribution can also be used to reflect a specific order in which the accounts should be filled. To do so, first fill a larger bookover account with the reservoir rights and use Type 6 operating rules to bookover the stored water into smaller accounts using appropriate priorities to control the order accounts are filled.
  • The amount that is booked over in these operations is reported in the operating rule summary (*.xop) file and in the reservoir summary output (*.xre) file. Note that the reservoir summary for each account reflects the bookover amount coming into or going out of the account. The bookover amount is double-counted in the reservoir summary for the total reservoir (Account 0), because it is reflecting the sum of the bookover amounts for all the accounts, which includes the smaller accounts and the larger “bookover” account. It is recommended the user refer to the individual account summaries in the reservoir summary file (*.xre) or the operating rule summary file (*.xop) for the amount booked over from one account to another.