Water Use Estimates Differ Within Park Rezone EIR

A site plan for a Southern Humboldt Community Park hydrologic study. The bulk of the water that would be used for the proposed athletic fields during the dry portion of the year would be drawn from "Water Source #1, the Eel River infiltration gallery." (Brad Job, Pacific Watershed Associates)

A site plan for a Southern Humboldt Community Park hydrologic study. The bulk of the water that would be used for the proposed athletic fields during the dry portion of the year would be drawn from "Water Source #1, the Eel River infiltration gallery." (Brad Job, Pacific Watershed Associates)

Everyone agrees that rezoning the Southern Humboldt Community Park to allow for athletic fields is going to significantly increase the amount of water the park draws from the South Fork of the Eel River for irrigation.

The question is how much.

An 852-page Draft Environmental Impact Report that came out in April evaluates a number of proposed land-use designation changes at the 405-acre park — including one that would allow for the staging of public festivals. But the massive document has not settled the irrigation issue. Instead, it has added a new layer of complexity.

The reason is that the EIR — which the public has until June 29 to submit comments on that will be responded to — contains two different sets of estimates provided by two different consultants.

The “water demand” projections that appear in the main body of the EIR were provided by GHD, Inc., an engineering firm with an office in Eureka. Those numbers, based on a study done in 2014, are considerably higher than those in an 18-page report released this past January by Pacific Watershed Associates, a McKinleyville outfit.

Since the latest educated guesses appear not in the EIR proper but in an appendix, one might think they carry less weight. But that’s not the case, according to Michael Richardson, acting supervising planner at the Humboldt County Planning Department.

“Both could be viewed as valid,” Richardson said this past Friday.

The potential for sizeable irrigation withdrawals has been a simmering issue for some time, not least because of opposition, or at least concern, from nearby landowners. Adding to the issue’s high profile is the fact that the water intakes for the Garberville Sanitary District and the Redway Community Services district are both located downstream of where the park draws water from the Eel.

Richardson made clear that the first phase of the improvement project, which calls for the installation of restrooms at Tooby Memorial Park along with other “low-level” construction efforts, would not dramatically change the community park’s water usage from what it is now.

It’s not until phase two, which commences three years into the project, that the water draws go up substantially.

“It’s fairly simple,” Richardson commented. “It has to do with the installation of the ballfields. That’s where the water use ramps up.”

“When they irrigate the grass fields, they’ll pull out way more water than they are currently using,” he added.

While there is more than one water source at the community park — such as a well at Tooby and a spring — it is the park’s infiltration gallery along the Eel that will supply the vast majority of the water for irrigation.

While the gallery is inundated during the rainy season and becomes part of the river, during the annual summer drought it is located approximately 150 feet from the river.

Richardson said that in August the draw from the gallery during the project’s first phase would be 23,000 gallons. In phase two, the draw to irrigate 10 acres of ballfields — the acreage analyzed in the EIR — soars to 2.1 million gallons.

A similar jump is projected in terms of annual use, from 152,000 gallons taken from the Eel during phase one to 10.9 million gallons during phase two.

The water needed for irrigation coincides, of course, with the onset of the annual dry season. While no water at all is needed for irrigation from November through March, the projected irrigation demand in April is 467,000 gallons. In May, it’s 1.4 million gallons, or a million gallons more.

“The water use really ramps up in May,” Richardson remarked.

The peak comes in July, when the forecast is 2.3 million gallons. In October, it’s back down to 837,000 gallons.

The numbers cited by Richardson are the numbers found in the EIR — in other words, the numbers produced by the GHD study. The numbers in the Pacific Watershed Associates report, as has been indicated, differ markedly in a downward direction.

For example, instead of 2.1 million gallons in August, the draw from the Eel in that month is predicted to be 1.2 million gallons, or 900,000 gallons less.  And instead of 10.8 million gallons, the annual irrigation demand is likely to be 6.1 million gallons — close to 5 million gallons less.

The reason for such differences is a little on the technical side.  In fact, it boils down, at least in part, to that four-letter word, math.

“The water demand model used by GHD is based [on an] equation [that] is not necessarily the best or most suitable approximation of sports turf. [It] estimates the amount of water needed to maximize grass regardless of climate conditions,” the Pacific Watershed report asserts.

“While this approach is technically acceptable, it overstates the projected irrigation water demand, especially for the sports field,” the report adds.

Among other things, the two studies differ over the likely amount of water loss from the sports fields via evaporation. The Pacific Watershed estimates also give greater weight to water conservation techniques.

Richardson, when asked, didn’t offer an opinion about the discrepancies between the two reports — other than to say that consultants, when doing such studies, typically “toss numbers at [something] and make the case.”

Southern Humboldt Community Park executive director Kathryn Lobato said the park chose to commission a second study after the first study’s shortcomings became clear. “When GHD did the study, its analysis was [based on] what a standard ballfield would use. Their numbers were based on typical engineering guidelines,” she explained.

“We wanted numbers to be included that were based on water conservation” and other mitigating measures, she added.

“It didn’t take into account things we might do” to reduce impacts, such as planting drought-tolerant grasses, she said, referring to the GHD study.

Nonetheless, Lobato stopped short of dismissing the GHD study altogether. “Consultants like to be conservative. When you’re doing an EIR, you have to reveal possible effects. So we felt it was proper to do the GHD study.”

The Pacific Watershed report recommended that if the river’s flow falls below 30 cubic feet per second — it stood at 17 cubic feet per second when personnel from the firm conducted a site visit last July — using the infiltration gallery as a source of irrigation water should be halted altogether.

“We suggest 30 cubic feet per second as an interim threshold, beyond which the sports field can only be irrigated with stored or recycled water,” was the way the report put it.

Brad Job, the Pacific Watershed Associates civil engineer who headed up the study, pointed out that at present the community park can legally withdraw water from the river when flows are as little as 2.6 cubic feet per second.

“We’re saying 30 cubic feet per second. So that’s an order of magnitude more protective,” Job commented.

Lobato indicated that the park would be willing to abide by such a restriction. “If the river gets to a specific level, we’ll stop taking water. We’ll develop alternative water storage to get through those times.”

“Letting fields go brown is something we plan to do,” she added.

To date, Lobato said the community park has spent “upwards of $250,000” on a total of roughly 15 consultant studies for the EIR.

While she said the result has been a thorough review of the proposed improvement project’s potential impacts — traffic is another issue that consultants have looked at, along with wildlife impacts and impacts to cultural resources — she made clear that she has some misgivings about the EIR process in general, which is required by the California Environmental Quality Act.

“It’s outrageously expensive for a small non-profit,” Lobato said. “The thing that breaks my heart is that all that money couldn’t have been spent on ballfields or better paths and trails, on something that would provide an actual benefit to the community.”

Lobato said the park has been able to undertake the project thanks to grants from entities such as the Humboldt Area Foundation and the McLean Foundation and because of support from the community.

“Community members stepped to the plate and gave us donations,” she explained.

As for what comes next, Richardson said that after the public comment period comes to a close at the end of this month, the Planning Department would “assemble” all the input and “make coherent recommendations” — first to the Planning Commission, and then, if the commission gives the project its imprimatur, to the Board of Supervisors, the ultimate decision-maker.

Lobato said she’s hoping for a final decision by August. Richardson was a little vaguer, saying that the matter would likely be decided before the end of the year.