How much water is released downstream from Lopez Dam?

  • The Lopez Project was designed to produce a long term annual average of 8,730 acre feet water per year (an acre-foot of water is 325,851 gallons). Of this 8,730 acre feet, 4,530 is contracted to municipal users in the five cities and Avila Beach area, the remaining 4,200 acre feet is for downstream uses. When the watershed produces more than 8,730 acre feet in a given year, the excess is stored in the lake and used in years when the watershed produces less than 8,730 acre feet. The rate at which water is released from the dam varies with the season. In winter months releases are reduced because downstream uses need less water, in summer releases increase to meet streamside and groundwater needs. In recent years, a typical winter release averages 3 cubic feet per second (1.9 million gallons or 5.95 acre feet per day), in the summer releases rise to as much 12 cubic feet per second (7.8 million gallons or 26 acre feet per day).
  • Most recently, in the 15 days between January 4, 2017 and January 19, 2017 the reservoir inflow was 3,192.25 acre feet. At 3 cubic feet per second, 89.25 acre feet was released downstream and 3,103 acre 2 feet were kept in storage. That is, 97.2% of the inflow was kept in the lake, and 2.8% was released downstream.

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1. Why is water being released from Lopez Dam?
2. How much water is released downstream from Lopez Dam?
3. Is there a plan to reduce releases if the water gets very low in the reservoir?
4. Do other reservoirs make similar releases?