DWR_3603743 - Laserfiche WebLink

c. On stream reservoirs are required to show the evaporative loss from the reservoir in order to administer the release of an equivalent volume of water to the river as required by C.R.S. 37-84-117(5). All reservoirs should account for evaporative loss. d. The sum of ALL accounts in storage must equal the volume associated with the daily gauge rod reading. No account, including the "owe the river" account is allowed to carry a negative balance. e. At a minimum, the accounting must include the following calculations: Daily change in storage. Yesterday's storage amount subtracted from today's storage amount will yield yesterday's change in storage. Computed Inflow. Computed Inflow is the volume of inflow to the reservoir for the purposes of administration (computed inflow = change in storage + evaporation + controlled release). Computed Inflow minus the volume that can be stored in priority by the reservoir equals the daily exchange potential to the reservoir (computed inflow — in -priority storage = exchange potential). III. Unauthorized Inflow. Unauthorized Inflow is the portion of the Computed Inflow that exceeds the in -priority storage and authorized exchange diversions (unauthorized inflow = computed inflow — in - priority storage - authorized exchanges). The Unauthorized Inflow is the amount of water that was required to have passed through the reservoir. IV. Owe the River (OTR) storage. OTR storage is the aggregated volume of Unauthorized Inflow that is not released by the reservoir. It must be calculated daily and tracked in a separate storage account. OTR must be released as soon as practical, but within 72 hours, unless a different timeframe is approved in writing by the Water Commissioner or Division Engineer. Multiple Accounts 4. Prior to storing more than one type of water in a reservoir, accounting forms for such storage must be approved, in writing, by the Division Engineer. Examples of storing more than one type of water include: a. Free river water stored for a new use within a reservoir. b. Using accounts to track priority filling in order to allow a reservoir to avoid having all the water count as senior storage at the start of a new twelve- month storage period. The "Owe The River" or "Admin Account" is used in most on channel reservoirs to track any out of priority inflows. This accounting can fluctuate daily but the balance will remain positive or zero. The balance of the OTR should not exceed 1 % of the volume stored in the reservoir, unless a different volume is approved in writing by the Water Commissioner or Division Engineer. If there is a day when the reservoir experiences a loss and the OTR account is zero, then the reservoir loss must be November 14, 2018 Page 2