My biggest complaint about the California Water Blog is that it left out the crucially important detail that they modeled a tunnel that is significantly smaller than the BDCP proposal while including a large diagram of conveyance clipped from the BDCP to suggest that they did.
And then the BDCP blog, written by DWR staff, falsely titles their blog post "Salinity Effect of BDCP on Delta Farming Minimal, Researchers Say."
However, I revisited the California Water Blog this morning to clip a quote, and I am happy to report that they recently added the following paragraph to the body of their original post and deleted the BDCP diagram. (confirmed in the Google cache version dated 11/20).
The study did not consider the specific changes in the state’s proposed Bay Delta Conservation Plan, which includes the governor’s “preferred alternative” to tunnel exported water under the Delta. The modeled tunnel operated under 1981—2000 water conditions with a capacity of 7,500 cubic feet per second – enough to transport up to 59 percent of average annual exports (4.9 million acre-feet), with the remainder continuing to be pulled through Delta channels to the export pumps.
The fact that the diagram was included and this paragraph was omitted from the original blog post does not absolve DWR and the BDCP blog for misreporting this information. The description of the small tunnel scenario is clearly stated on page 35 of the full report which was released 10 months ago. If BDCP is really about science and facts, shouldn't we expect them to read and accurately describe the reports they cite rather than reinterpret them through a political lens.
The edits do not totally let the UC-Davis researchers off the hook either for what a colleague of mine describes as "feeding the animals." They left this important detail out of the summary of the original report as well. That summary discusses current policy proposals without explaining the differences between their scenario and the proposals. And while the BDCP is now moving towards reducing the capacity of the intakes and lower levels of water delivery (details to be released soon), at the time the PPIC report was released and the research was done, the leading BDCP proposal was clearly for a 15,000 cfs facility and 5.9 maf of average exports, and had been for several years. I complained about it in a post on this blog the day after the report was released in January.
Before anyone reads the summary of the new PPIC report and concludes that Delta residents don't have much to fear in the BDCP or the Delta Plan, they should understand exactly what the PPIC has modeled. When it comes to the big issues of water quality and habitat, it looks more like the recommendations of the Delta Protection Commission's Economic Sustainability Plan than the BDCP.Finally, the California Water Blog post states that the DPC Economic Sustainability Plan and an earlier PPIC report had much higher estimates of losses (the 2008 PPIC report actually estimated hundreds of millions of dollars in losses). However, the peripheral canal endorsed by the PPIC in their 2008 report was an isolated conveyance facility (not dual conveyance) that diverted 6 maf of water from the north Delta; double the quantity conveyed around the Delta through a facility in this latest report. And the DPC Economic Sustainability Plan report that I led looked at the actual BDCP proposal at that time, the 15,000 cfs tunnels with 5.9 maf of average exports. The differences in approach between our report and PPIC are much more than this though, but I will save that for a future post that explains the differences, and the advantages of our approach.
1. They assume water exports through a dual conveyance system will average 4.9 maf per year (see page 36 and 40) matching the 1980-2000 period. This is barely any increase over the constraints on through Delta pumping under the Biop. So, yes, under those operating assumptions dual conveyance would have a relatively small impact on Delta water quality. But does anyone really think that exporters will pay billions for conveyance that delivers 4.9 maf? My understanding is exporters have made it pretty clear that they won't, and draft BDCP documents and the superficial discussions of finance suggest substantially higher exports of 6 maf or possibly more. On page 40 they do note that some exporters are seeking 6 maf, but that is not what they modeled in their report...
If the BDCP doesn't actually significantly affect Delta salinity, these differences in economic modeling are irrelevant. The surprising discovery in the PPIC report results from the suprising result of their hydro-dynamic modeling, not any advanced economics. No change in salinity obviously means no economic impact from salinity changes, this is clearly stated in the DPC Economic Sustainability Plan.
Thus, I wish the PPIC would write some blogs explaining their hydro-dynamic results in plain English since this is their most important and surprising result. While I have no reason to doubt the results, I would like to better understand how it is possible to take 3 maf out of the Sacramento River without a larger impact, and I would be interested how their results change if more were diverted through the tunnels, if the results depend on or assume any change in upstream operations and flows, etc.
While they are at it, they should allow comments on their blog, so they can be conveniently alerted to parts that confuse people or even the occasional error or omission. In this case, there is a good chance that some simple blog comments would have prevented Ms. Vogel at the BDCP Blog from making her mistake. And how can they be the California Water Blog without the validation of a Mike Wade comment?
[Note: Original post edited to mention the BDCP diagram.]