Signs posted on trees along the watershed’s boundary threaten would-be trespassers with prosecution. Among the few who are allowed on this land, owned by the City of Seattle, are 60 workers with Seattle Public Utilities. They oversee the operations that protect the water and assure its delivery to 1.4 million Seattle area residents. That water is pushed by gravity through over 20 miles of pipeline and into their homes. When it arrives, it does so unfiltered; the watershed is one of only five sources in the country so clean they do not require expensive filtration systems to strain out sediment and other impurities.

While most of the region’s residents may only enjoy the watershed from a distance, the borders are slightly more porous for enrolled members of the Muckleshoot Indian Tribe. As part of a hard-fought settlement agreement between the tribe and the city in 2006, members are allowed limited access for traditional purposes — the gathering of firewood and other resources, as well as some hunting and fishing. This was their right, after all, guaranteed in treaties from the mid-1800s, and entrance was reaffirmed as part of a broader package of reparations in 2006.

But 12 years after signing on to the agreement — seen at the time as historic in its focus and scope — the city and the tribe have still never fully defined the rights of entry for the Muckleshoot tribe. The issue was tabled until 2014 when the tribe made what seemed like a simple request to the city: to camp.

The continued negotiations that followed and still continue today have exposed a conflict between the city’s desire to respect the tribe’s cultural practices and its obligation to protect a coveted municipal water supply. What is for the tribe a fairly logical extension of their long-held treaty rights is to the city an ask that must be vetted through many layers of bureaucracy. If it is not, officials fear, the result could be an end to the city’s right to provide unfiltered water and a subsequent $500 million piece of capital infrastructure.

At issue for the tribe is a list of specific requests issued to the city years ago, requesting camping access and use by family members. The tribe would like family members who are not tribal members — which can include husbands, wives, children — to join enrolled members when entering the watershed. Members of the Muckleshoot Tribal Council have also requested camping privileges there and to have occasional campfires “for cultural and ceremonial practices.”

But what are to tribal members minor adjustments to the settlement have been so far interpreted by city officials as a threat to the watershed’s delicate ecosystem and not in accordance with the deal. And so balancing how much access is appropriate remains unresolved.

The discussion is now before Jenny Durkan, the sixth Seattle mayor to handle the massive 2006 settlement since the agreement was originally signed. As a onetime lawyer for the tribe, she’s recused herself from the discussions. But that ends next month, a year after she took office.

Questions about access to the Cedar River Watershed are rooted in the signing of the treaties of Medicine Creek in 1854 and Point Elliot in 1855, land deals between local tribes and the settlers who were arriving from the east. In accordance with that treaty, native people of the greater Puget Sound region ceded territory to white settlers in exchange for the promise of reservation land and the freedom to hunt, fish and gather resources in ancestral lands off reservation, including the Cedar River Watershed.

“The treaties did more than provide lands for non-Indian settlers,” said Anita Mitchell, Vice Chair of Muckleshoot Tribal Council. “They cemented into federal law the preexisting right of tribes to hunt, fish and gather in the same manner as before the treaties were signed.”