In 2013, Hawaii’s statewide water usage was 449 million gallons per day (mgd). Using this figure as the baseline, coupled with projections for population increase, it is estimated that 100 mgd of additional fresh water capacity* is needed in order to meet Hawaii’s future water demands without extracting more valuable groundwater resources or resorting to high cost alternatives such as desalination. To achieve this ambitious goal, key stakeholders across the public, private, and philanthropic sectors must work together on conservation, reuse, and recharge initiatives.

* Fresh water capacity refers to the amount of water available for consumption, and can be defined as the total decrease in water demand combined with the increase in water supply.

CONSERVATION

164 GALLONS OF WATER A DAY PER PERSON

Water conservation is the most efficient and cost effective way to manage the demand on Hawaii’s limited fresh groundwater resources. Conservation can be achieved through improving the efficiency of residential and agricultural water use. Since a quarter of all water pumped statewide is used for agriculture (see Figure 1), Hawaii should focus on improving efficiency in agriculture water use by 15% by 2030.

Hawaii residents currently use 164 gallons of water per day per person (approximately 33 buckets full), which needs to be reduced to 130 gallons per day per person to achieve Hawaii’s 2030 goal.

Figure 1: Reported Water Use Data in Percent by Island and Sector 2016 (Not all water use data was reported, reporting compliance = 48%).

RECHARGE

7.5% RISE IN PAVED PARADISE

Water recharge delivers rainfall and surface water back into aquifers. Over time, developed areas and pavement has changed the way water naturally recharges by preventing water from being absorbed back into the earth. From 2005 – 2011 there was approximately a 7.5% increase in development and paved areas statewide (NOAA C-CAP). In addition, changes in upland forest have reduced the amount of direct water recharge. Recharge can be improved through increasing upland forested protection (Visit Watershed) and increasing green infrastructure. Metrics to measure green infrastructure are still being defined and will be tracked as new green infrastructure projects are completed.

REUSE

16.4% OF WASTEWATER BEING REUSED

Approximately 120 million gallons of wastewater from treatment plants are discharged daily. To divert wastewater to other fresh water uses, Hawaii should: 1) Ensure that the right quality water is matched with the right and safe end use and 2) Eliminate barriers to recapture and reuse. The cost to treat and reuse recycled water can be as much as twice that to produce potable water. To reduce costs, strategically placed small-scale water filter plants can divert wastewater for non-potable applications, including irrigation for parks, golf courses, and local agriculture. To reach the reuse target, the freshwater council set the aspirational target of reaching 40% reuse by 2030. Currently 16.4% of Hawaii’s wastewater is reused statewide.

Figure 2: State of Hawaii Wastewater Reuse

Source: Department of Health, Wastewater Branch

Fresh water targets were produced in collaboration with the Fresh Water Council, an innovative collaboration between federal, state, county, nonprofit, academic,and private sector stakeholders with expertise in water issues. For more detailed information on the Council and targets refer to A Blueprint for Action.

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