Laserfiche WebLink
Vallecito Reservoir Storage Right <br />Name Adjud. Date Approp. Date Admin. No. Amount <br />(ac-ft) <br />Vallecito Reservoir 03-07-1966 11-13-1935 31362.00000 129,674 <br />There is also a conditional water right for hydroelectric power generation through a penstock at <br />the base of the dam. This water right was adjudicated in December 1980 for 720 cfs and has an <br />appropriation date of June 1, 1979. <br />Monthly records of the historical inflows to Vallecito Reservoir, end of month (EOM) storage <br />contents and releases from the reservoir were obtained from the USBR through 1993. Under <br />current operation of the reservoir, the storage releases during the irrigation season are <br />determined by the Pine River Irrigation District based on the natural flows available for <br />diversion and anticipation of the following year's runoff. At the end of the irrigation season, the <br />reservoir is typically drawn down to approximately 77,000 acre-feet to prepare for the spring <br />runoff and to maintain a winter water surface elevation well below the spillway crest. Forecasts <br />for the anticipated snowmelt runoff into the reservoir are provided by the National Weather <br />Service on a twice monthly basis, beginning in January and continuing through July. During <br />January, February and March, the amount of storage capacity required for flood control is <br />determined using relations developed by the Corps of Engineers and releases are made as <br />necessary to make the flood control space available. During the peak runoff period, releases are <br />adjusted to maintain the flow in the Pine River to a rate less than 2,500 cfs. Peak snowmelt <br />runoff occurs during late May or early June. The reservoir usually reaches it peak storage <br />levels by July 1. The reservoir levels then decrease as the runoff subsides and irrigation water <br />is released. <br />During the winter season, the required release is equal to the reservoir inflow. However, in <br />order to minimize cavitation of the regulating gates, the releases through the outlet works have <br />been maintained at a minimum of 30 to 50 cfs. In addition, winter releases through the <br />hydropower penstock are typically about 20 cfs. <br />In the original USBR analysis of the project, the total irrigation requirement was based on the <br />assumption of 3.28 acre-feet of delivery per acre over the then anticipated 51,825 irrigable <br />acres, resulting in a prof ect demand of 169,986 acre-feet per year. This is considered to be a <br />full water supply. According to the water commissioner for District 31 and personnel at the <br />Pine River Irrigation District, the actual amount of reservoir storage water delivered to the <br />stockholders and the Indian facilities is typically less than the 125,000 acre-feet in the active <br />storage pool. Historically, there has always been sufficient storage water, when used in <br />conjunction with the adjudicated direct flow water rights, to satisfy all of the irrigation <br />demands. <br />Nearly all of the major irrigation structures that divert from the Pine River are entitled to <br />prof ect water from Vallecito Reservoir. These include the Indian owned irrigation ditches that <br />hold the No. 1 priority on the river (Pine River Priority P-1). The P-1 priority is attached to the <br />following ditches: <br />San Juan & Dolores River Basin Information 2-19 <br />