On July 20th, the State Water Resources Control Board California Environmental Protection Agency issued a draft Development of Flow Criteria for the Sacramento-San Joaquin Delta Ecosystem report. According to Mike Taugher of the Bay Area News Group, “The key finding is that of all the snowmelt and rain that falls into the Delta’s watershed, which covers 40 percent of California, about 75 percent of it should be allowed to flow through the Delta into San Francisco Bay.”
“Today, only about 50 percent of the flow passes through the Delta on average as nearly all of California taps into its rivers and the Delta itself.”
To browse through the entire 180 page report, click here. The report states:
“In order to preserve the attributes of a natural variable system to which native fish species are adapted, many of the criteria developed by the State Water Board are crafted as percentages of natural or unimpaired flows. These criteria include:
- 75% of unimpaired Delta outflow from January through June;
- 75% of unimpaired Sacramento River inflow from November through June; and
- 60% of unimpaired San Joaquin River inflow from February through June.
- approximately 30% in drier years to almost 100% of unimpaired flows in wetter years for Delta outflows;
- about 50% on average from April through June for Sacramento River inflows;
- approximately 20% in drier years to almost 50% in wetter years for San Joaquin River inflows.
In comparison, historic flows over the last 18 to 22 years have been:
The report is not surprising to Delta scientists or even residents of the Delta. It has been obvious for years that export levels have been the key cause of the Delta crisis. The Delta needs sufficient fresh water flowing through it to flush out pollutants, to provide fresh water for fish and stream wildlife, and to maintain the quality of the water for healthy use by humans (swimming and other recreation).
Now everyone is asking what the state is going to do about it. This is not the first time this information has been provided. When the federal pumps were first installed, environmentalists sent letters of concern to the then governor Jerry Brown worrying that turning on all five pumps would destroy the Delta. Some years later the 5th pump was turned on. And we all know the crisis the Delta is in now.
- Yubanet.com Delta Flows article.
- Calsport Press Release
- RestoreTheDelta.org – “Now we know how much water needs to flow” and “A purely theoretical exercise?”