Kaua‘i streams flowing at record low levels

Without significant rainfall between now and the start of the “normal” dry season, state hydrologists say drought conditions throughout much of Hawaiʻi will significantly worsen, exacerbating already extremely low water levels of island streams.

Especially on Kauaʻi.

The water level in Kawaikōī Stream in West Kaua‘i, which drains a portion of the Garden Isle’s vast Alaka‘i Plateau, probably looks fine to the untrained eye. But stream flow data gathered by the Hawai’i Commission on Water Resource Management tell a far — and alarmingly — different story.

“This stream is flowing at record low flows for the last 7 to 9 months,” said the commission’s lead hydrologist Aryon Strauch. “Right now, we’re at about 20% of normal flow for this time of year, which does not bode well for the dry season. This is typically the wettest part of the year.”

The U.S. Geological Survey National Water Dashboard showed flow at 12:20 p.m. Thursday at Kawaikōī Stream was at 9.15 cubic feet per second, below normal for this time of year but steady.

Some streams on Kauaʻi and other places throughout the state are already completely dry.

“We are seeing record low flows in terms of the entire period of record on Kawaikōī, that’s about 109 years. In some of the East Maui streams, 105 years,” said Strauch. “But we’ve not seen low flows like this across the state to this extent ever before.”

That’s affecting water availability for drinking water supplies, for traditional and customary practices, and for agriculture.

The U.S. Drought Monitor shows that most of Kaua‘i County, or 86.93%, is experiencing moderate drought as of March 11, with 5.65% under severe drought conditions and the remaining 7.42% being abnormally dry.

A total of 62,111 people in the county, or 92.6%, are affected by drought right now.

The state Commission on Water Resource Management team uses sophisticated instruments and data from permanent stream flow measurement stations to regularly monitor the conditions of 80 waterways statewide.

The outlook is particularly bleak in west Kaua‘i and east and west Maui.

Water managers such as Mike Faye with the Kekaha Agriculture Association will be faced with distributing a dwindling supply of water to ag users and — unless conditions improve — expect some to be left high and dry.

“Our role is to take care of the infrastructure, which consists of two ditch systems that come out of the mountains in Kōkeʻe — the Kekaha ditch and the in Kōkeʻe ditch,” said Faye.

The association also operates two hydroelectric plants it maintains, along with 30 miles of power lines and 30 miles of roads.

If water flows continue to drop, the power it produces could cease along with water delivery to the nine leasees on mauka lands above Kekaha and the Mānā Plain.

That is 13,000 acres in total, which formerly supported Kauaʻi’s plantation-era sugar industry. The agriculture tenants are licensed through the state’s Agribusiness Development Corporation.

While water from the Kōkeʻe ditch continues to spill into Pu‘u Lua Reservoir, even without measurements, Strauch and his team can tell the volume is quite low.

With the data they are collecting, they can show it to people who might otherwise not be noticing.

“One of the benefits of having long-term data sets is being able to talk about the severity of the drought conditions being observed relative to 100 years of record, and by explaining that these are unprecedented flows,” Strauch said.

The shoreline expands every day as water levels in the popular trout-fishing spot continue to drop.

“For the last 9 months, we’ve only had maybe 12 days of peak flow conditions, which is very unusual, and we can compare that to a normal year, where we might have 60 days of peak flow conditions,” Strauch said. “The availability of water is just severely limited. Despite the water flowing in the stream, it’s just not flowing very much.”

He hopes late winter rains will continue to improve the water situation statewide, but in case that doesn’t happen, water conservation will be key.

“Obviously, this impacts people who are directly reliant on the streams,” Strauch said. “But long-term agriculture and other off-stream uses that may not be the priority of the public trust uses of water, they’re going to suffer because we just don’t have enough water right now to meet the demands.”