“This Commission action is a first step in seeking balance and equity for these streams that have been diverted for over 100 years,” Kaleo Manuel, deputy director of the state Commission on Water Resource Management, said in a news release Thursday.

The decision on Tuesday came after four years of work by the commission’s staff, including hundreds of days of field work in the region to develop an improved understanding of the hydrology, ecology and community uses of the streams, according to the state Department of Land and Natural Resources. Commission staff also explored how modifications to the EMI system can better protect instream uses.

Each of the streams varies in length, flow levels, the type of wildlife found in the area and what they’re used for, including farming, household needs or recreation. Many will require modifications to diversions in the area — such as sealing up leaks, installing plates across grates or closing up and abandoning a diversion — to allow the streams to reach the flow that water commission staff are recommending.

Commission hydrologist Ayron Strauch explained to the commission on Tuesday how modifications to the EMI system would enhance downstream habitat and upstream connectivity for native stream biota by keeping about 40 percent of the water in the streams.

A waterfall is seen on Hoolawa Stream. The state water commission set interim in-stream flow standards for 12 Huelo streams and tributaries this week, returning water to some streams that have been diverted for more than a century. — Photo courtesy of Commission on Water Resource Management

“What’s very noteworthy in the Huelo region in particular is that there are a number of riparian uses or registered stream diversions that are not EMI diversions that draw water from the stream for small-scale agriculture and other uses,” he said.

The total amount of water available in the Huelo region ranges from about 25 million gallons per day at medium flows and about 5.5 mgd at extreme low flows, Strauch said. Each of the streams does gain some flow between the upper and lower ditches, but this depends on the groundwater recharge, and the less rain there is, the less groundwater contributes to streamflow.

The island has seen “substantial declines in rainfall over the last century,” particularly between 1983 to 2012, and even more recently during extreme drought conditions, all of which has resulted in drops in streamflow, Strauch said. The two U.S. Geological Survey stations in the area have seen declines ranging from 11 to 50 percent.

Strauch explained that setting interim instream flow standards will provide for registered riparian uses (for those living or located along the edge of the streams), recreational uses and improvements to the estuary and nearshore ecosystem.

On Tuesday, the Sierra Club applauded the decision to set streamflow standards “after more than a century of complete devastation for dozens of streams in East Maui.” However, the club said it believed more water should be returned to the streams.

“Both this Commission and the Division of Aquatic Resources have concluded that a minimum of 64 percent of each stream’s median base flow is necessary to provide suitable habitat conditions for recruitment, growth, and reproduction of native stream animals,” the club said in written testimony. “Yet, few, if any, of these streams are being restored to that level in their upper reaches. And three streams will continue to see all their water taken.”

However, Sierra Club attorney David Kimo Frankel said at the meeting that the organization supports revisiting the numbers in four years as the commission recommended “so that we will all have a chance to see how things are going and see if these numbers need to be adjusted.”

“We think more water’s going to need to be restored, but we understand the need to see how these measures work,” Frankel said.

Mahi Pono, which owns half of EMI along with Alexander & Baldwin, also said that it “strongly supports” the interim instream flow standards.

“The Commission Staff has spent years gathering and analyzing data related to stream flows in East Maui,” Grant Nakama, vice president of operations, wrote in testimony to the commission. “The Staff’s current proposal to amend and establish flow standards is representative of a practical and reasonable application of this analysis and the balancing test that is required by the IIFS process.”

The company also backed setting aside water for DHHL usage, which the commission also approved on Tuesday. DHHL is asking for nearly 11.2 mgd of nonpotable water from the East Maui system for its Pulehunui and Keokea-Waiohuli homesteads, and commission staff recommended setting aside 1.3 mgd from the Huelo region.

“We are pleased to support a balanced outcome that addresses two DHHL surface water reservations through the adoption of the Commission Staff’s data-driven stream flow recommendations,” Nakama said. “This dual-purpose solution is much more credible than any piecemeal alternative that would otherwise diminish the years of data gathered by the Commission’s Staff.”

The next step is for EMI to submit necessary permitting to construct modifications, some of which require that the company submit a timeline to implement the changes within 60 days.

Meredith Ching, who represented EMI and Mahi Pono at the meeting, said the 60-day request “could be tight” given that the winter months are coming up.

“I would just ask for some understanding on that, but we will do our best and push as hard as we can,” Ching said Tuesday. “There’s just a couple people who do this, who go in the field and figure out what needs to be done and then figuring out the permitting implications, whether that’s an SMA or needs federal review, etc.”

Helene Kau, director of the Maui County Department of Water Supply, also expressed the county’s support for stream restoration and setting instream flow standards.

“But we’re also uncertain if the remaining flow at the Wailoa Ditch, particularly during periods of extended drought, will hurt domestic needs for our Upcountry customers,” Kau said.

Commission staff plan to holding quarterly meetings to bring those affected by the EMI system together to discuss the implementation of the interim instream flow standards, and the water needs of Maui County’s Department of Water Supply, DHHL, Mahi Pono and the community at large.

* Colleen Uechi can be reached at cuechi@mauinews.com.