Description

The Yukon Flats Lowlands MLRA is an expansive basin characterized by numerous levels of flood plains and terraces that are separated by minimal breaks in elevation. This MLRA is in Interior Alaska and is adjacent to the middle reaches of the Yukon River. Numerous tributaries of the Yukon River are within the Yukon Flats Lowlands MLRA. The largest are Beaver Creek, Birch Creek, Black River, Chandalar River, Christian River, Dall River, Hadweenzic River, Hodzana River, Porcupine River, and Sheenjek River. The MLRA has two distinct regions—lowlands and marginal uplands. The lowlands have minimal local relief and are approximately 9,000 square miles in size (Williams 1962). Landforms associated with the lowlands are flood plains and stream terraces. The marginal uplands consist of rolling and dissected plains that are a transitional area between the lowlands and adjacent mountain systems. The marginal uplands are approximately 4,700 square miles in size (Williams 1962). This MLRA is bounded by the Yukon-Tanana Plateau to the south, Hodzana Highlands to the west, Porcupine Plateau to the east, and southern foothills of the Brooks Range to the north (Williams 1962). These surrounding hills and mountains partially isolate the Yukon Flats Lowlands MLRA from weather systems affecting other MLRAs of Interior Alaska. As a result, temperatures are generally warmer in summer and colder in winter than is characteristic in other areas at comparable latitude. There is a moisture and temperature gradient in which the lowlands region tends to be drier and colder and the surrounding marginal uplands region tends to be moister and warmer (PRISM Climate Group 2006). The Yukon Flats Lowlands MLRA is mostly undeveloped lands that are sparsely populated and not accessible by a road system. A number of villages, including Beaver, Birch Creek, Chalkyitsik, Circle, Fort Yukon, Stevens Village, and Venetie, are adjacent to the Yukon River or one of its major tributaries. The largest village is Fort Yukon, which according to the 2010 U.S. Census has 583 residents that are dominantly Gwich’in Alaska Natives.

Geographic subunits

Land Resource Unit 1. While Alaska has no officially recognized land resource units (USDA Agriculture Handbook 296), there appears to be two distinct regions in the Yukon Flats Lowlands MLRA. These distinct regions are thought to have differing climatic regimes, landforms, and soil types (STATSGO and Jorgensen and Meidinger 2015) and will be termed the lowlands LRU and the marginal uplands LRU. LRU 01 refers to the lowlands region.

Land Resource Unit 2. While Alaska has no officially recognized land resource units (USDA Agriculture Handbook 296), there appears to be two distinct regions in the Yukon Flats Lowlands MLRA. These distinct regions are thought to have differing climatic regimes, landforms, and soil types (STATSGO and Jorgensen and Meidinger 2015) and will be termed the lowlands LRU and the marginal uplands LRU. LRU 02 refers to the marginal uplands region.