A wetland unit at Lower Klamath National Wildlife Refuge. When water doesn’t flow to these units during the summer, their water levels can get low enough for botulism outbreaks to form. This year, late summer water deliveries from the Klamath Project have prevented current outbreaks from worsening.

Editor’s note: This is the second of a two-part series on the Klamath Basin wildlife refuges’ botulism outbreak. Part 1, published August 23, details how botulism works and how the refuges are responding to the outbreak.

While the Klamath Basin National Wildlife Refuge Complex deals with one of its biggest botulism outbreaks in recent history, emergency water deliveries from the Klamath Project have prevented the situation from worsening.

The waterborne bacterial illness, which causes paralysis and often leads to death, has impacted more than 15 percent of the molting birds currently on Tule Lake’s main sump.

The bacteria thrive in exceptionally shallow, warm water, of which there was a particular abundance this summer: Lower Klamath and Tule Lake Refuges, which have depended on the Klamath Project for water for more than half a century, have felt the dry sting of drought alongside irrigators.

Normally, water deliveries to the refuges enter a maintenance status during the summer. Refuge wetlands need to grow food for the hundreds of thousands of birds that visit the basin throughout the year. The water comes from the Klamath River via the Ady Canal and Tule Lake via the D Plant.

But going into this summer, refuges had not received a significant inflow since last fall. Water levels in Tule Lake’s Sump 1A and Lower Klamath’s Units 2 and 3 — the three main areas of open water and permanent wetland between both refuges — were extremely low. Once temperatures peaked during mid-July, conditions were ripe for botulism.

Greg Austin, project manager for the Klamath Basin Refuge Complex, said an arrangement with the Bureau of Reclamation and the Klamath Project Drought Response Agency prevented the outbreak from getting even further out of control, but botulism wasn’t the initial reason for it.

Originally, water was needed to maintain habitat for breeding birds on Lower Klamath and suckers in Tule Lake. Austin said conversations about getting the refuges some project water during the summer had been occurring since February.

Reclamation began diverting 30 cubic feet per second of water into Lower Klamath Refuge on July 15, and began diverting 100 cfs into Tule Lake about two weeks ago.

Marc Staunton, chairman of the KPDRA, said that “excess” water was created by compensating farmers and ranchers for voluntarily idling their land or switching to groundwater irrigation this year. The project water they would have used to irrigate was then sent to the refuges.

“We have a common interest, and our water moves commonly together,” Staunton said. “I don’t think any farmer wants to see the refuges go dry and have botulism outbreaks that are catastrophic.”

Refuge biologist John Vradenburg said curbing a botulism outbreak (beyond removing affected bird corpses) means either adding cooler, fresher water onto a wetland or draining it entirely.

On Lower Klamath, when botulism began popping up in Unit 3 in mid-July and the refuge didn’t have any extra water to work with, the only option was to drain what was supposed to be a permanent wetland.

Unit 2 then became the only open-water bird habitat on the refuge — and an eventual convalescent home of sorts for botulism survivors from Unit 3 and Tule Lake. But it was in danger of experiencing its own outbreak, too.

The 30 cfs of fresh, cold water that has been flowing constantly into Unit 2 has infused the wetland with oxygen and prevented the bacteria from taking hold, effectively making it a safe haven in a refuge choked by waterborne illness.

Because the Caldwell Fire prevented refuge staff from responding to Tule Lake’s outbreak in time, the 100 cfs that has been flowing into Sump 1A for about two weeks has yet to curb the outbreak. But Vradenburg said it should keep the disease from worsening there until nighttime frost conditions begin to defeat the bacteria next month.

“If we didn’t get any water, we’d be dealing with a pretty large outbreak on all three units,” he said.

Austin said the Lower Klamath delivery is scheduled to continue through September while the Tule Lake delivery will go through August.

Refuge managers are grateful for the water, which has allowed them to avoid a truly catastrophic outbreak, but it’s currently not enough to refill Unit 3 and create the habitat necessary to sustain the upcoming fall bird migration.

Vradenburg said this summer illustrates the problem with the way water deliveries are currently set up. When refuge managers don’t know how much water they’ll get during a given year or even when they’ll get it, planning a response to potential outbreaks becomes difficult.

“It’d be better to get water earlier on and more consistently rather than throwing water at the problem,” he said. “If this is the trend on water deliveries, this is probably the future we’re going to be looking at every summer.”