Maui Nui stream flow conditions are shown here on March 3. According to the Hawai‘i Department of Land and Natural Resources, stream flows on Maui are at record lows and that’s a cause for concern going into what’s typically known as the dry season. Photo courtesy DLNR

According to hydrologists with the Hawai’i Commission on Water Resource Management, stream-flow measurements are extremely low for this time of year on Maui.

“This stream is flowing at record low flows for the last seven to nine months. Right now, we’re at about 20% of normal flow for this time of year, which does not bode well for the dry season,” Aryon Strauch, CWRM’s lead hydrologist, explained in a news release. “This is typically the wettest part of the year.”

Without significant rainfall between now and the start of the “normal” dry season, this winter’s drought conditions across much of Hawai’i are expected to worsen significantly.

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

Some streams are already completely dry and that’s affecting water availability for drinking water supplies, for traditional and customary practices, and for agriculture.

As a result, the state says water managers like Mike Faye of the Kekaha Agriculture Association will be faced with distributing a dwindling supply of water to ag users, and unless conditions improve, some can expect 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,” Faye said in a statement.

The association also operates two hydroelectric plants which it maintains, along with 30 miles of power lines and 30 miles of roads. If water flows continue to drop, the power they produce 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.

“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 added.

Maui County has already imposed various stages of water conservation to try to ease the current water shortage, but state officials warn that if dry conditions persist, some users could be left high and dry. Photo courtesy DLNR

Maui County has already imposed various stages of water conservation to try to ease the current water shortage, but state officials warn that if dry conditions persist, some users could be left high and dry. Photo courtesy DLNR

“For the last nine 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. The availability of water is just severely limited. Despite the water flowing in the stream, it’s just not flowing very much,” he said.

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

Using instruments and data from permanent stream flow measurement stations, the CWRM team monitors conditions of 80 waterways statewide. The outlook is particularly bleak in west Kaua’i and in East and West Maui.

“Honokōhau Stream, in West Maui, the medium flow for this time of year is about 20 cubic feet per second, or about 12 to 13 million gallons per day,” Strauch said.

Last week the stream was flowing at eight to nine CFS, or five and a half to six million gallons per day, which was, a third or 25% of normal flows. Recent rains have improved the Honokōhau Stream flow to 11.8 CFS.

Wailuku River in ʻĪao Valley saw improved stream flow over the past week, moving from 15 CFS to 22 CFS.

“Normal flow is about 25 and again, these flows are supplying water for drinking water supply,” Strauch said. “They’re supplying water for in-stream values, and it becomes a real challenge to manage water demand and water availability when we’re trying to protect a number of competing public trust uses.”

Rain-rich East Maui is experiencing the same record-breaking low stream flows. Maui County has already imposed various stages of water conservation because of the current water shortage and for what’s predicted across the summer and into the next wet season.

“Obviously this impacts people who are directly reliant on the streams. 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,” Strauch said.

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, he said.