Canal Loss (Seepage) as an Augmentation Supply

StateMod allows canal loss (seepage) to be used as an augmentation plan supply and estimates the amount of this supply based on the amount of water carried to a demand, the efficiency of the canal, and the location and timing the canal loss (seepage) accrues to the river. The lagged canal loss is stored in a specific recharge plan and can then be “released from” (accounted at) the plan as a supply to offset an augmentation requirement. Canal loss used as an augmentation supply must be designated by an operating rule and therefore requires a carrier structure that diverts to meet a separate demand. Canal loss experienced by a diversion structure diverted based only on a diversion right cannot be stored in a recharge plan. As canal loss is reaching the river regardless if there is an augmentation requirement, the recharge plan only accounts for the loss as a supply in the given time-step the lagged canal loss accrues to the river and the plan does not need to be “spilled”.

1. Open the network (*.net) in StateDMI, navigate to the appropriate location, and right-click to Add an Upstream Location. Enter the appropriate location and structure information and designate the structure type as a plan.
   • It is recommended the plan ID reflect the augmentation plan ID it will supply along with a suffix indicating it will store canal loss (e.g. _PlC for the Plan Canal).
2. Recreate the river network file (*.rin) to reflect the additional structure.
3. In the plan file (*.pln), include the canal loss recharge plan as a Type 8 Plan and include the appropriate parameter information. See Section 4 for more discussion on the information in and format of this file.
4. Using a text editor, create the plan return (*.prf) file which includes return flow data used to route the canal loss back to the river. See Section 4 for more discussion on the information in and format of this file.
   • The return flow location and patterns in the plan return (*.prf) file should be similar to the return flow information for the carrier structure in the diversion station (*.dds) file.
   • Canal loss from the recharge plan may be routed to any number of stream locations using any number of unit response functions, however the unit response functions must be included in the delay table (*.dly or *.urm) file.
5. In the operating rule (*.opr) file, include a Carrier with Transit Loss (Type 45) operating rule from the carrier to the demand including the canal loss recharge plan in the rule (creuse field). The second line of the Type 45 operating rule indicates the percent of canal loss.
   • Note that in many cases, only the canal loss associated with specific water rights can be used as an augmentation supply. Include the canal loss recharge plan only with operating rules carrying water rights with their canal loss decreed as an augmentation supply.
   • Consider including a Release Limit Plan in the operating rule to limit the overall total of all recharge supplies, including canal loss recharge.
6. In the operating rule (*.opr) file, include a Plan/Reservoir Reuse to Plan by Direct or Exchange (Type 48 and 49) operating rule in order to apply the water stored in the canal loss recharge plan to offset augmentation requirement.
   • Note that the water stored in the plan is the lagged accretions to the river and will offset the lagged depletions in the augmentation plan in the same time step, if any.
   • The source in this rule is the canal loss recharge plan and the destination is the augmentation plan.
   • If no Type 48 or 49 rule is included, the canal loss will return to the system but is not considered as an augmentation supply, therefore a Plan Spill (Type 29) operating rule is not needed.
7. Review the plan summary (*.xpl) file for information on the total canal loss recharge plan supply and the portion of the augmentation requirement that was offset by the supply.

Example Plan Return (*.prf) File (see also the full-size image)

Example Operating Rule (*.opr) File (see also the full-size image)