HYDROGRAPHY OF ALASKA'S NATIONAL PARKS IN THE CONTEXT OF ANILCA AND NAVIGABILITY

The United States Congress passed Alaska National Interest Land Conservation Act (ANILCA) in 1980, protecting millions of acres of land throughout Alaska. ANILCA is the largest expansion of protected lands in history. Conservation of such vast amounts of land has unique complications, notably protecting rights of Alaska’s Indigenous Peoples and other rural subsistence users. Existing private, native, and state-owned land within the newly-formed conservation areas were considered when creating ANILCA, leading to provisions that prevent their regulation as federal lands.

In 2019, the Supreme Court unanimously ruled on Sturgeon v Frost. This case was about river usage within the Yukon-Charley National Rivers Preserve. The Court relied on the navigability determination of the Nation River. Navigability is a legal determination of land ownership of submerged lands. The Court concluded that because the Nation River is navigable, the submerged land beneath it is State land, and the National Park Service (NPS) cannot enforce their regulations given ANLICA. The wake of that ruling has created an uncertainty of who has authority over waterbodies within the National Parks in Alaska.

This has facilitated the need to examine the navigability of the Alaska’s National Parks Rivers. Although the Bureau of Land Management (BLM) is delegated the authority to make navigability determinations, these are time-intensive and may be subject to litigation. Concurrently, the NPS is creating a geomorphic map of rivers throughout the Alaska region to inform managers about the characteristics likely to affect transportation over the waters. ArcMap was used to examine the hydrography of National Parks in Alaska. Here, I present new mapping of Alaska’s river network using the most recent 5m statewide digital elevation model. Stream order calculated by the Strahler method and slope are used to classify and weight river segments by relative potential for transportation. Using these river properties, land ownership, and existing BLM determinations, the NPS will be able to create a hydrographical map of park lands in the Alaska region showing areas of likely federal management authority and areas that require further evaluation based on other factors.