KANEOHE—Over the next decade, a variety of new water projects will take place in each ahupuaa across Oahu as recommended by a new statewide comprehensive water management plan.
The Honolulu Board of Water Supply (HBWS) is aiming to complete Koolaupoko’s 400-page stew of data and project recommendations by early next year. Similar plans for Waianae and Koolauloa are completed and can be viewed at the HBWS website.
As a stipulation of the 1987 State water code, the City and County of Honolulu is required to create an Oahu Water Management Plan. Since the late 1990s, the plan has been undergoing research, consultation, and reworking as its formulators at the HBWS discovered management inevitably requires an eye for conservation.
“Essentially the law mandates that this plan should be one of water use and development,” said Barry Usagawa, HBWS Water Resources Program Administrator. “When we tried to do this plan, the community was basically saying, “That’s only half the story. What about protecting the resource?” After a number of tries, we retooled the approach and called it the Watershed Management Plan, which takes a holistic view of water, balancing the protection with its use and development and conservation of resources.”
Usagawa explained that HBWS looked closely at incorporating a traditional Native Hawaiian model for water management.
“The model that we used was the ahupuaa model, which was suggested to us by a number of community leaders,” Usagawa said. “The ahupuaa concept is really about going back to how Native Hawaiians managed the water and had a balance between protecting the environment and utilizing the resource in an economic system of bartering between farmers and fishermen, for instance. Then they had social rules—you couldn’t pollute the water. Everyone had a responsibility to respect and use it wisely.”
What evolved was a City-implemented system that allowed for economic, social, and environmental values. And due to the variety of micro-climates and water systems on Oahu, the eight land use districts are each forming their own plans.
The consultation process has included landowners, community groups, and non-profits in community meetings.
At the meetings, Usugawa said, “Everything came out. They talked about diversions—for kalo, for agriculture, Waihole ditch. Other issues were polluted streams, flooding, not enough water for ag, the cost of water, the quality of water. What they suggested was they needed to have a balance between protection and use and we have some ideas about how to restore some resources.”
As a result, the objectives of the plan propose questions to finding a balance between protection and use: What action can be taken? How do we protect water quality and quantity? How do we protect Native Hawaiian rights? How do we involve and educate the community? How do we meet demand?
Some of the imperatives include the restoration of streams, removal of invasive species, replenishment of stream flow by removing concrete, and the balance of flood control. Itemized lists of specific projects in each ahupuaa are also included in the plans.
Koolaupoko’s watershed and water needs
In addition to creating a list of project recommendations and funding opportunities, the HBWS study also provides a much-needed inventory and outline of the Koolaupoko watershed and communities’ water demands.
The Windward side of Oahu does not generally ship water out, but rather imports about 7 million gallons per day (mgd) from Koolauloa. The annual total consumption for Koolaupoko is about 16.15 mgd. Currently the HBWS pumps about 14 mgd, well below the 40 mgd “sustainable yield” recommendation.
About 63 percent of water consumed is for residential use. Kailua has the largest demand for water on the Windward side and the largest groundwater sources are in Kahaluu. The U.S. Government is the second largest user at 13 percent, followed by commercial use at 11 percent, and agriculture use at just 5 percent.
Koolaupoko does have higher rainfall, up to 196 inches annually. However, in a drought, that number can sink to as low as 31 inches.
“You think Windward’s pretty wet,” Usagawa said. “But when there’s a drought, that place is the first place that feels the drought because the dike aquifers are smaller.”
Due to limited natural storage capacity, droughts hit Koolaupoko hard.
“So while Pearl Harbor can withstand droughts of two to three years,” Usagawa continued, “[for Windward Oahu], after a year or so ... it depends. In Windward I don’t need to water grass, but in a drought, everybody starts using more water because normally they rely on rainfall. ... This Koolaupoko plan is trying to keep the water in the ground as much as possible. If we can do that then we are promoting a sustainable watershed and enhancing and protecting water quality and quantity.”
In terms of development and potential water need, factors like the proportion of residential to agriculture usage, as well as what is being grown, must be taken into account.
“Koolaupoko is low-growth area for urban,” Usagawa said. “It’s pretty much a static in terms of the amount of people. On our data we showed a decrease in population over time, which amounts to less people per household. They’re stable communities. A lot of kids are moving out, but [there is] very little development.”
The Water Management Plan takes into account three projected scenarios—of low, middle, and high growth—for population growth based on the current 37,189 housing units per 118,763 people.
“The biggest factor for water in Koolaupoko would be the agricultural potential both in restoration and in diversified agriculture,” Usagawa said.
The prospect of expanded agricultural demands depends on how much land could potentially go under cultivation. Of Kaneohe’s 1,248 available ag lands, 399 remain available. Of Kailua’s 2,021, 586 are available. And of Waimanalo’s 2,167, 292 are available.
For kalo growth, 269 of Kaneohe’s 1,355 suitable acres are still available, 685 of Kailua’s 1,037 are available, and nine of Waimanalo’s 1,107 are available.
“Is there enough water to supply all the ag land in Koolaupoko?” Usagawa speculated. “No. Not enough water. Especially when you’re looking for huge amounts for kalo—100,000 to 300,000 mpg—that’s huge. With that kind of amount, you’re not going to see a whole lot of kalo.”
Agriculture, particularly kao, are the biggest water use factors being taken into consideration, Usagawa said. In addition to drought, the smaller dike sources present a big x-factor when it comes to planning.
While the urban areas in Kaneohe and Kailua are huge, they don’t rely on water sources from within Koolaupoko. Kaneohe and Kailua rely on imported water from Koolauloa and Kahaluu. The stream flow gets taken out of Kailua into Waimanalo from Maunawili, which points to strong potential for conservation in urban areas like Koolaupoko, Usagawa said.
Although the Windward side is relatively static in terms of residential development, development is still anticipated to occur in the future. The hope is that, in the formulation of the plan, the community can be engaged to better understand and appreciate their water systems, and enable the necessary conservation efforts.
Call to action
Funding is and will always be the crux of the plan’s implementation, although the fulfillment of a mandate to complete a comprehensive plan is in-and-of-itself a justification for funding.
“The main objection I’ve heard on this plan is, “How are you going to fund all these projects?’” Usagawa said. “It’s a huge undertaking. And that’s true. We don’t have all the funding. But the plan is basically to be used to justify the funding.”
The HBWS intends to access funding for projects that already have established “champions.”
“To implement, you need a champion,” Usagawa explained. “It’s not a capital improvement plan. It’s a long range plan over 20 years and it provides guidance to the City and the State and landowners and groups as to how they can use the resources.”
Usagawa described the process by neighborhood board district: “We wanted to identify a watershed in each area where we would focus our attention. Waihee for Kahaluu because we have an active partnership, we own land, we have a big source there, we have to protect it. We want to basically help the existing initiatives. The one in Kaneohe will probably the Heeia wetland. There’s lots of community involvement there. For Kailua it would be Kawainui—that whole watershed up to Maunawili. In Waimanalo, I don’t know yet. It’s primarily ag. Every summer the farmers run out of water. The State puts them on 20 to 30 percent cutbacks. We’ve got to find an additional source for them. They divert Manuwili ditch water that would otherwise flow to Kawainui Marsh. To restore Kawainui Marsh we have to get the state to take more water from farmers, but the farmers need more water.”
Channeling funds to community groups already on the ground is half of the equation. The other half lies with the HBWS infrastructure itself.
The HBWS has a 25-mile system of infrastructure serving Koolaupoko. Unfortunately, the water infrastructure itself is not watertight, leading to significant water supply loss just from transport. In Waimanalo, for example, just .4 mgd is received at the end of a system that initially inputs 1.5 mgd. Waihole ditch loses about 15 mgd.
“If we fix the leaks in the plumbing systems, develop rainbarrel catchments tied to house gutters, they can use that water to water their potted plants,” Usagawa said. “There’s recycled water in Waimanalo. All these strategies connection to the stream. If we use less, we pump less, indirectly then we’re restoring stream flow. We’re keeping our water levels up in our aquifers to mitigate drought. The point is these strategies all integrate together—not just trying to develop another well to meet demand, but instead let’s just use what we have now more efficiently so we don’t have to drill another well. How can you promote a sustainable watershed when you develop a well in that watershed? It doesn’t really match. Conserve water that’s being pumped.”
Ultimately, whatever shape the HBWS plan ends up taking, true water conservation on Oahu is going to require cooperation between the producers and consumers of water to enhance local resources. Another series of community meetings is upcoming, and the plan, once completed, must be ratified by all four neighborhood boards in Koolaupoko to be enacted.
“What this plan is doing is tying land use and water together, and developing watershed protection projects the partnership would start to work on,” Usagawa said.
For notes about individual ahupuaa, including a current and future predicted water use slideshow, visit http://www.boardofwatersupply.com/cssweb/display.cfm?sid=2127.