Friday, December 24, 2021
Humboldt County via email
Re: Comments on Draft Groundwater Sustainability Plan
Dear Hank and Groundwater Team:
Thank you for the informative presentation on the draft GSP last Friday. The following brief notes and comments may help to improve the final plan.
At this writing, several technical memos remain outstanding. We may comment on them when they are posted.
The draft GSP taught me Townsend’s big-eared bats drink water.
The final GSP should note that Northern California summer steelhead were listed by the California Fish and Game Commission this summer as Endangered under the California Endangered Species Act.
As we noted Friday, one of our key concerns is the way the sustainable management criteria for depletion of interconnected surface water is stated. Any action that “… threatens the viability of a special-status species…” would, for species like Chinook salmon and steelhead listed under the federal Endangered Species Act, be an action that jeopardize those species. The threshold for impacts to listed species should be lower than jeopardy or, for that matter, take.
If the threshold for impacts to listed species were take, then the county would need to be prepared to immediately curtail pumping that could affect surface flows. Instead, the rest of the Significant and Unreasonable use statement says “… and reasonable reductions or limitations in groundwater pumping could avoid these effects without jeopardizing other beneficial uses of groundwater.” That looks like a rule that says groundwater pumpers never have to stop pumping if they don’t want to.
We would suggest that the undesirable result that should trigger analysis is depletion of surface flows such that beneficial uses are impaired. If restricting groundwater extraction could help diminish impacts to public trust resources, the county has a duty to consider how such restrictions can be imposed.
The draft GSP estimates evapotranspiration from natural vegetation and from irrigated agriculture, but then presents those results as part of the same category. What proportion of evapotranspiration is from irrigated agriculture alone?
In its analysis of salt intrusion and sea level rise, the draft GSP uses a figure of 0.5 feet of sea level rise by 2030 and 1.48 by 2070. These estimates seem improbably conservative. How would the analysis change if you doubled those figures? Note for example that recent reports suggest the Thwaites Ice Shelf is likely to collapse in the next three to five years, entraining several feet of sea level rise from the resulting speedup in the Thwaites Glacier behind the ice shelf:
The failure of the shelf would not immediately accelerate global sea level rise. The shelf already floats on the ocean surface, taking up the same amount of space whether it is solid or liquid.
But when the shelf fails, the eastern third of Thwaites Glacier will triple in speed, spitting formerly landlocked ice into the sea. Total collapse of Thwaites could result in several feet of sea level rise, scientists say, endangering millions of people in coastal areas. (See Washington Post, December 13, 2021.)
Similar reports from Greenland suggest Humboldt is likely to see at least three feet of sea level rise well before 2070. The GSP should note that the lower Eel and Humboldt Bay is now seeing sea level rise at the highest rate in coastal California, because the land at the coastal margin is sinking due to tectonic forces at about the same rate that saltwater is presently rising.
The draft GSP notes in several areas the relative proportion of wells in various categories without ever revealing the actual numbers behind those proportions, e.g. agricultural uses account for 86.4% of groundwater use. How many agricultural wells are we talking about? What are their capacities? Where are they located? How much water have they been pumping? The county has that information or has the power to require that information be disclosed.
It would be much easier to understand the economics and impacts of groundwater pumping if we had a clearer picture of who is using how much water, when, and why. Maps showing densities of wells per square mile are harder to prepare than maps of the actual wells. Why obscure the details of water use in the lower Eel? How has pumped groundwater been used, ie at what rates on what crops? Similarly, the final GSP should detail the history of well drilling in the lower Eel over the last several decades, or at a minimum the last 10 years. How many new wells have been drilled, where, and to what depths?
The draft GSP notes that CASGEM well readings are ‘generally stable.’ Please report the outlier numbers as well as the broader trends. The draft GSP notes that the flows of the Eel River are key to maintaining groundwater levels in the Lower Eel. At what point would diminishing flows in the Eel begin to reduce groundwater levels in the basin?
With respect to the county’s well permitting process, the draft GSP is not clear how or by what standards the county evaluates proposed wells. How does the county ensure that wells are not improperly sited, for example not sunk in areas where they would tap subsurface flows? And how does the county consider the potential effects, including cumulative effects, of approving well permits and operations?
The Water Year Type chart on page 72 of the draft GSP presents the last 30 years of water year data at Ferndale as a color-coded bar chart, with annual precipitation varying from a low of just over 20 inches in 2014 to a high of about 65 inches in 1998 and 2017. Five of the first fifteen years were below average water years. Ten of the second fifteen years were below average. This trend shows that even on the coast we are not immune from the effects of climate change, including the collapse of the assumptions of hydrological stationarity that have been the premise of water management over the last century.
Of course, given the relationship between flows in the Eel River and the lower Eel groundwater basin documented in the draft GSP, precipitation in Ferndale should be considered together with related data, including the even steeper decline in precipitation and increase in temperatures in the inland portions of the Eel River basin. As well, given the increase in groundwater demand associated with higher temperatures, the GSP should present data regarding temperature changes both in the lower Eel basin and the interior which affect not only crop demands but snowmelt, vegetation uptake and transpiration, and impacts on salmonid populations.
We are heading into a future where the lack of precipitation alone is likely to continue to create hostile conditions in our rivers and streams for native fish. As the draft GSP documents on page 24, groundwater diversions are higher in drier and warmer years. Those are of course the years in which potential impacts to fisheries and other beneficial uses of surface water can be critical, not to mention significant.
The draft GSP explains that parts of Humboldt county and indeed parts of the lower Eel Groundwater basin are disadvantaged communities such that the California Department of Water Resources judged it appropriate to grant the county funds to support this planning effort without a cost-matching requirement. It would be difficult to support that argument on the basis that the people who own the land and run the irrigation pumps are disadvantaged.
It seems clear the draft GSP is written to ensure the irrigating community is in no way inconvenienced by any requirement that it change, or even report, its groundwater use. Treating the uses of the lower Eel River valley’s land and water that have become entrenched over the last century as entitlements does not make them sustainable. Practices that ensure native species can continue to thrive are those which can be sustained.
Thank you for all of your work on this plan and the technical material supporting it.