Naturally occurring long-term mean annual recharge to ground water in Nebraska was estimated by a novel water-balance approach. This approach uses geographic information systems (GIS) layers of land cover, elevation of land and ground water surfaces, base recharge, and the recharge potential in combination with monthly climatic data. Long-term mean recharge > 140 mm per year was estimated in ea...

The Utah sucker (Catostomus ardens) is endemic to the Bonneville Basin and the upper Snake River drainage in western North America, and is thought to hybridize with the federally endangered June sucker (Chasmistes liorus mictus) in Utah Lake (Bonneville Basin). Here we describe the discovery of a major subdivision in Utah suckers (4.5% mitochondrial sequence divergence) between the ancient Snak...

Glacial mapping combined with cosmogenic exposure dating provides the first detailed assessment of the late Pleistocene glacial history in the northeastern Brooks Range, Alaska. Former ice limits were identified in the Okpilak, Jago, Aichillik, Egaksrak, and Kongakut River valleys. Relative-weathering data support our correlations with the wellstudied glacial sequence of the central Brooks Rang...

In unconfined parts of the Chalk aquifer in southeast England, permeability generally varies laterally with the lowest permeabilities occurring beneath interfluve areas, and the highest beneath river valleys and dry valleys. Furthermore, the Chalk in the river valleys is normally in excellent hydraulic continuity with the overlying highly permeable Quaternary gravels. However, recent field inve...

a r t i c l e i n f o Railroads and roads are ubiquitous features in the river corridors of the United States. However, their impact on hydrologic, geomorphic, and ecological processes in fluvial and riparian landscapes has not been systematically explored at regional or continental extents. This study documents the geographic distribution of roads and railroads in the alluvial floodplains of t...