This category is used to specify how the storage account calculates the Initial Request in the water rights allocation. The methods in this category are valid only if the account has a water right as specified by the Priority Right method.

This method allows the user to specify that the appropriation of water to this account is the amount of water that it takes to fill the conservation pool. The total volume of paper water in all storage accounts on a reservoir contributes to the conservation pool volume, regardless of the ownership of the water in these accounts.

The amount of water required to fill the conservation pool is calculated as follows: At the beginning of each timestep, the reservoir object determines a value to place in its series slot Conservation Pool Initial Empty Space if that slot does not already have a value for the current timestep.

The value calculated is the amount of inflow needed to fill the conservation pool. This flow is computed by calling the reservoir’s utility function massBalanceSolveInflow, given zero outflow and the elevation of the top of the conservation pool, as defined by the slots Top of Conservation Pool, Operating Level Table, and Elevation Volume Table. The mass balance utility method takes into account all the method selections on the reservoir, including those for evaporation and precipitation, and the current Pool Elevation of the reservoir. The value in the Conservation Pool Initial Empty Space is based on data on the simulation object (that is, wet water) and does not take into consideration any data on the accounts (paper water).

When the water allocation solver computes the physical constraints applicable to a storage right and when it computes the appropriation request for a storage right that has the Fill Conservation Pool method selected, it starts with the current value of the Conservation Pool Initial Empty Space slot on the underlying Reservoir object. If this value is not defined, and the solver in use is SolveWaterRightsWithLags, the solver will force the reservoir to compute this value. From that value it subtracts inflows, slot inflows, and net transfers in (subtracts transfers in, adds transfers out) to all the storage accounts on the reservoir; the remainder is the inflow that will fill the conservation pool on the reservoir. If this value is less than zero, zero is used. This is the desired initial appropriation request. This initial appropriation request amount is subject to the optional Fill Factor; see Conservation Pool Fill Factor.

This method is similar to the Fill Conservation Pool method, but it allows more water to be requested in order to meet the Initial Requests of Diversion Accounts on Water Users that are directly supplied by this account and its sibling storage accounts. See Fill Conservation Pool for details.

The amount of water required to fill the conservation pool is calculated exactly as for the Fill Conservation Pool method. To this amount is added the sum of all the Initial Request values on all Diversion Accounts supplied by this storage account or by its sibling storage accounts. If this amount is less than zero, zero is used.

From this value it subtracts inflows, slot inflows, and transfers in to all the storage accounts on the reservoir; the remainder is the inflow that will fill the conservation pool on the reservoir and meet diversions. Again, if this value is less than zero, zero is used. This is the desired initial appropriation request. This initial appropriation request amount is subject to the optional Fill Factor; see Conservation Pool Fill Factor.

In this method, the user can specify the Initial Request via Input, DMI, or Rules. If one of the non-default methods is selected in the Operating Levels category on the reservoir, the filling the conservation pool will also limit the allocation. This method is then available to further limit the allocation.