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Sal Mangiafico, Rutgers Cooperative Extension
The New Jersey Water Supply Plan
The New Jersey Department of Environmental Protection is currently working on revising the statewide Water Supply Plan.
This plan aims to balance traditional uses of water like residential, commercial, industrial, and agricultural irrigation with ecological sustainability of streams and other waterbodies.
The last full revision was released in 2017. The full document can be found at NJDEP (2017) in the References (www.nj.gov/dep/watersupply/pdf/wsp.pdf).
A draft of the new plan is slated to be released in Spring of 2023. For more information, see NJDEP (2023) in the References (dep.nj.gov/water-supply-plan/).
With New Jersey being the most densely populated state, along with significant land devoted to agriculture and maintained landscapes, water conservation planning is critical for the state for sustainability of its population, industry, and environment.
Planning for sustainability
Planning for water availability and use on this scale is complex.
There are many water users to consider, from municipal water systems to large industrial sites to individual farms. Some parts of the state are more densely populated, while important users in other parts of the state may include farmland and irrigated landscapes.
The available water varies in different geographic regions, and the effects on smaller watersheds need to be considered.
Managing and predicting available water is also complicated by variation in weather. No one can predict the amount or timing of rainfall.
As a further complication, in places where significant water is used for the irrigation of crops and landscapes, water sources are likely to be further taxed when rainfall is low and irrigation amounts are higher. Streams and wetlands are likely to be stressed more during drought periods as well.
Considering the state’s population, the Metropolitan Planning Organization estimates an increase in New Jersey population of more than 8% from 2020 to 2050, giving New Jersey an estimated population of more than 10 million by 2050 (NJDEP, 2021). The largest increases are expected in urbanized counties, specifically Hudson, Bergen, Essex, Ocean, and Middlesex Counties.
The state relies on good planning to manage water sources, voluntary water conservation, and water use permitting to achieve its sustainability goals.
Looking at sources and uses
It’s estimated that New Jersey uses more than 1-and-a-half billion gallons of water per day.
Figure 1 shows a draft plot of water use in New Jersey by water source. In the state as a whole, surface water bodies—including drinking water reservoirs—are the largest source of water (about 70% in recent years). Unconfined aquifers—including the vast Kirkwood–Cohansey aquifer— are the next largest source (about 20% in recent years), followed by confined aquifers (about 10% in recent years).
Also notable in Figure 1, is the consistent decrease in water used overall across decades. But this trend may not be seen in all geographic areas or all business sectors.
Potable water use and landscape irrigation
Figure 2 shows a draft plot of water use in New Jersey by water use group.
Ignoring water used for power generation, Potable Use is the largest use of water in the state (about 70% in recent years). Potable use includes municipal water systems that feed homes and businesses.
It’s also notable that potable water use increases substantially in summer months. This is probably largely driven by lawn and landscape irrigation. As noted, this is also the time of the year when maintaining water sources is critical to sustain streams and wetlands. It’s likely that water conservation efforts focused on limiting lawn and landscape irrigation will be necessary for the state’s water conservation efforts.
Industrial and agricultural use
Commercial / Industrial use (about 9% in recent years) and Agricultural use (about 5% in recent years) are far smaller, though may be important in some locations.
More detailed information
More detailed data, including information on smaller geographic areas can be found in the 2017 plan, and likely in the upcoming 2023 plan.
Becoming involved
The state Water Supply Advisory Council typically meets monthly and advises the state on water supply planning from the point of view scientists, residents, agriculture, industry, and other stakeholders. Information on the Water Supply Advisory Council can be found at: dep.nj.gov/water-supply-plan/water-supply-advisory/.
References
Department of Environmental Protection [NJDEP]. 2017. New Jersey Water Supply Plan 2017-2022. www.nj.gov/dep/watersupply/pdf/wsp.pdf. For appendices see: www.state.nj.us/dep/watersupply/wsp.html.
New Jersey Department of Environmental Protection [NJDEP]. 2021. Water Availability and the Water Supply Plan. Water Supply Plan Stakeholder Advisory Group October 12, 2021. dep.nj.gov/wp-content/uploads/water-supply-plan/water-availability-water-supply-plan-20221012-stakeholder-mtg.pdf.
New Jersey Department of Environmental Protection [NJDEP]. 2023. New Jersey Statewide Water Supply Plan. dep.nj.gov/water-supply-plan/.
Figures
Figure 1. Water use by source in New Jersey. Image source: NJDEP (2021).
Figure 2. Water use by use group in New Jersey. Image source: NJDEP (2021).