Too much rain in the winter, too little in the summer: Potable island water is a limited resource, the quantity and quality of which increasingly are determined by the climate, hydrology and the growing population of year-round residents, retirees and work-at-home digital nomads. 

A top health concern in San Juan County and on Guemes and Lummi islands is seawater intrusion when wells are drawn down too much. The problem is exacerbated by summer water use when the island population blossoms with tourists and visitors.

Kyle Dodd, Environmental Health Manager for San Juan County, said there is a general concern for water availability.

“I don’t know exactly how climate change will affect that but we have had a concern for a couple of decades and have furthered several studies trying to gain additional knowledge of what we have for water availability in certain areas,” Dodd said.

In July, San Juan County’s Planning Commission incorporated the Water Resources Element to its Comprehensive Plan. Dodd said water availability is “very much part of that element and will be incorporated in the comprehensive plan.”

Climate change is just the latest additional challenge with water availability issues, Dodd said. In San Juan County, a United States Geological Survey (USGS) study is ongoing and expected to be completed by the end of 2022 or by the first quarter of 2023. 

Dodd said climate change is not specifically part of the study but thinks it will lay some groundwork for directions to seek additional data moving forward.

An island problem, under study

Dodd said the county is looking forward to an updated water balance study and groundwater recharge information.

“We’re a county of islands that is solely dependent on rainfall for our recharge and our surface water for drinking,” Dodd said. “What we’re expecting from [the water balance] is to give an idea of available water for drinking and other fish and wildlife uses.”

By calculating the rainfall that falls on the islands and subtracting what runs off into the Salish Sea, what is withdrawn from wells and lakes and consumed, Dodd said this study will give an idea of what remains and is available. 

“We can use that as a planning tool moving forward,” Dodd said.

Seawater on Guemes Island

Guemes Island is facing a problem of seawater intrusion in wells. Skagit County Commissioner Ron Wesen said as water use goes up, the chances of saltwater entering thinner areas of the freshwater aquafer increases.

“That’s the concern, and some of the wells that were located closer to the [shoreline] have had increased chloride level, or salt, and that definitely affects them,” Wesen said. “Anytime people draw water out of the aquifer, if it’s not being replenished, we have a chance of saltwater intrusion.”

This year, residents asked for the monitoring of saltwater intrusion on Guemes to be included on the county’s Comprehensive Plan docket but the county commissioners voted the proposal down. Wesen said the upcoming USGS survey for Guemes’ aquifer starting in September will allow Skagit County to address the concerns.

“With that information, we’ll be able to make some decisions, hard decisions, on how do we protect the people that are there now,” Wesen said.

Keeping an eye on saltwater intrusion

Dodd said there a couple of areas in San Juan County that have an increased risk of saltwater intrusion, such as the north end of Lopez Island, which is composed of sand, gravel and glacial outwash aquifers. 

“That is an area that we have an existing groundwater monitoring network to keep us informed on changes,” Dodd said. “We’ll be able to respond accordingly if we start seeing that seawater intrusion drastically change.”

Because these water quality and quantity issues can have serious impacts for communities on the islands, Wesen said there has to be awareness and public education on the issues at hand and residents need to know how sole source aquifer affects everybody.

Educating on aquifers and a finite resource

Mike Skehan, a retired water distribution specialist who has managed water systems on Lummi Island, has published articles alongside Isaac Colgan for a series called Water Watchers, and is working with the Lummi Island Heritage Trust to organize the Water Challenge in an effort to engage residents with the concerns over freshwater resources.

He said Lummi Island hasn’t had major issues with saltwater intrusion so far.

The Environmental Protection Agency (EPA) considers wells with chloride levels exceeding 250 parts per million to be unsafe for drinking.

The last study done on the island goes back to 2006 when 5 out of 40 wells studied showed those kinds of levels. Skehan said there are more than 400 wells on the island.

“It’s not a topic that is talked about on the island,” Skehan said. “I don’t know of any wells right now, off the top of my head, that had been abandoned because they went over that 250 threshold.”

The main concerns for Lummi Island relate to aquifer replenishment and possible resource exhaustion in the future.

According to Skehan, the island gets 34 to 35 inches of rainfall per year, but only about 6% of that actually makes it down into the aquifer. In fact, he said, twice as much water that replenishes the island’s freshwater aquifer comes from residents’ septic systems.

“Homeowners are really, really encouraged to protect what they put into the aquifer, when about twice as much water is recycled from their septic tank, and only about a third of it comes from the rain,” Skehan said

[Editor’s note: In a follow-up email, Skehan corrected his statement to clarify that, of the total amount of water that recharges the aquifer, 12% comes from septic systems.]

Skehan said the first solution that comes to mind for water resource concerns on islands would be conservation. 

“Meters are a great way to do that, “ he said. “People don’t like to have their water metered but usage fees are a way proven by the state of Washington to reduce demand,” Skehan said.

Increasing the island’s capacity to store rainfall rather than letting it run off would be another way to ensure aquifers are replenished. Skehan said forests and trees can increase storage capacity, too.

“They absorb the water, hold it and let it go back into the soil slowly and that’s a good reason on top of other reasons to keep our forest intact,” Skehan said.

Both Wesen and Dodd underlined the importance for islands residents to be aware of these issues and be educated on ways to limit water consumption and preserve the resource.

“Everybody should just be aware of the limited nature of our water,” said Dodd. “All of our water comes from rainfall and what doesn’t run off the landscape is available for use, but it is definitely finite.” 

Dodd said appreciating the limited nature of that and understanding the value and use of water efficiently can go a long way.

Development on the islands is being examined as communities and housing keeps growing. Skehan said the Growth Management Act passed in 1990 dictates that localities can’t outrun their resources, whether it be transportation or water or any other resource that the community relies on. 

“That’s the starting point and kind of the basis for any county planning efforts or subarea planning efforts,” Skehan said. “How much growth can you accept and still be within the mandates of the act? I think that’s a good a good number to know.” 

Growth room on Lummi

On Lummi island, Skehan said there are about 1,000 full time residents, a number that grows in the summer. 

“The current subarea plan estimates that we could absorb, with proper planning, proper controls and monitoring, up to 3,000 residents,” Skehan said. “We’ve got some room to grow, definitely, but we don’t want to grow unrestricted. It should be a methodical, well-thought out plan.”

When it comes to implementing solutions, Dodd said San Juan County is in a position of data collection to try and assess where water resources on the islands currently are. 

“I know that one solution in areas with limited groundwater or where seawater intrusion has become an issue, some of our local water systems have turned to desalinization systems,” Dodd said. “If a water system adjacent to marine water has the ability to install an intake and a treatment plant, then certainly that is an option for some of those areas in our county.”

Mostly, counties are asking island residents to use the limited water more efficiently to conserve available water.

“We just take it for granted because it’s so readily available in the Northwest,” Wesen said. “We need to understand that it’s a scarce resource.”

On Aug. 22, the Lummi Island Heritage Trust will host a Zoom meeting with Mike Skehan and Isaac Colgan, writers behind the Water Watchers series, accompanied by Washington State Department of Health hydrogeologist Sheryl Howe, to discuss “island aquifers and steps islanders can take to protect their private wells.”

— Reported by Clifford Heberden

See also:
“Have enough water? San Juan prepares to find out, with USGS study,” Salish Current, July 21, 2021
“Water supply on Guemes: an island paradise faces challenges,” Salish Current, July 27, 2021.

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