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Albuquerque Area Office

Water Operations Group

Operations Fact Sheet
Cochiti Lake

GENERAL

  • Purpose: Flood and sediment control, fish and wildlife enhancement, and recreation.
  • Owned by the U.S. Army Corps of Engineers.
  • Cochiti is the primary flood control structure for snowmelt runoff control on the mainstream of the Rio Grande.

STORAGE

  • Congress authorized the storage of San Juan-Chama (SJC) water in Cochiti in order to maintain a permanent pool for recreational purposes and for fish and wildlife. SJC water is stored in Cochiti each year to maintain a reservoir surface of 1,200 acres.
  • Cochiti frequently stores significant amounts of spring and early summer runoff that would cause flooding downstream. The dam is operated to release stored water as quickly as possible without causing downstream flooding.

RELEASES

  • General plan for operating is to bypass the entire natural inflow up to a channel capacity of 7,000 cfs at the Albuquerque gage. Releases from Cochiti Dam and Jemez Canyon Dam are kept below this flow rate.
  • Rate of release, whether increasing or decreasing in stage, is generally held to 0.50 feet at the downstream gage. The limitation on the increase in stage at the downstream gage is based on public safety. The limitation on the decrease in stage in the downstream gage is based on preventing bank sloughing.
  • Release changes are not made in less than one-hour intervals when possible.
  • Release rates are adjusted to evacuate flood storage within a short period of time, usually within a 24-hour period after the peak inflow of a thunderstorm event. Duration of the evacuation depends on the volume. Release rates are also adjusted based on tributary inflow below the dam from a thunderstorm event. These measures are taken to protect downstream structures from flood damage.
  • SJC water released from upstream reservoirs destined for Cochiti Lake (evaporation replacement water) is stored and all other SJC water is passed through.
  • SJC recreation pool serves to increase trap efficiency.
  • Public Law 86-645 After July 1st when the flow at the Otowi gaging station drops below 1,500 cfs, the Corps may not release flood waters stored in Abiquiu and Cochiti reservoirs. There is one exception to this criteria and that is when Cochiti has less than 212,000 acre-feet of summer space.

**** All data are provisional and subject to revision as final data are collected and analyzed. ****

Email comments/inquires to: rabeyta@uc.usbr.gov

 

Last updated: January 23, 2007