Geology Reports⌕ Search

Geology topics

D. Rosenberry

Publications and source records attributed to D. Rosenberry.

5 recordsLinked to original sources
USGS2007

Hydrologic response of the Crow Wing Watershed, Minnesota, to mid-Holocene climate change

In this study, we have integrated a suite of Holocene paleoclimatic proxies with mathematical modeling in an attempt to obtain a comprehensive picture of how watersheds respond to past climate change. A three-dimensional surface-water-groundwater model was developed to assess the effects of mid-Holocene climate change on water resources within the Crow Wing Watershed, Upper Mississippi Basin in north central Minnesota. The model was first calibrated to a 50 yr historical record of average annual surface-water discharge, monthly groundwater levels, and lake-level fluctuations. The model was able to reproduce reasonably well long-term historical records (1949-1999) of water-table and lake-level fluctuations across the watershed as well as stream discharge near the watershed outlet. The calibrated model was then used to reproduce paleogroundwater and lake levels using climate reconstructions based on pollen-transfer functions from Williams Lake just outside the watershed. Computed declines in mid-Holocene lake levels for two lakes at opposite ends of the watershed were between 6 and 18 m. Simulated streamflow near the outlet of the watershed decreased to 70% of modern average annual discharge after ???200 yr. The area covered by wetlands for the entire watershed was reduced by ???16%. The mid-Holocene hydrologic changes indicated by these model results and corroborated by several lake-core records across the Crow Wing Watershed may serve as a useful proxy of the hydrologic response to future warm, dry climatic forecasts (ca. 2050) made by some atmospheric general-circulation models for the glaciated Midwestern United States. ?? 2007 Geological Society of America.

Geological Society of America Bulletin↗
USGS2006

Flow path oscillations in transient ground-water simulations of large peatland systems

Transient numerical simulations of the Glacial Lake Agassiz Peatland near the Red Lakes in Northern Minnesota were constructed to evaluate observed reversals in vertical ground-water flow. Seasonal weather changes were introduced to a ground-water flow model by varying evapotranspiration and recharge over time. Vertical hydraulic reversals, driven by changes in recharge and evapotranspiration were produced in the simulated peat layer. These simulations indicate that the high specific storage associated with the peat is an important control on hydraulic reversals. Seasonally driven vertical flow is on the order of centimeters in the deep peat, suggesting that seasonal vertical advective fluxes are not significant and that ground-water flow into the deep peat likely occurs on decadal or longer time scales. Particles tracked within the ground-water flow model oscillate over time, suggesting that seasonal flow reversals will enhance vertical mixing in the peat column. The amplitude of flow path oscillations increased with increasing peat storativity, with amplitudes of about 5 cm occurring when peat specific storativity was set to about 0.05 m-1. ?? 2005 Elsevier B.V. All rights reserved.

Journal of Hydrology↗
USGS2005

Comparison of wetlands in different hydrogeological settings under conditions of extreme climate variability

Wetlands in the Cottonwood Lake area in North Dakota, USA, are underlain by poorly permeable till and have little groundwater input. Lakes and wetlands in the Shingobee River headwaters in Minnesota are underlain by permeable sand and have substantial groundwater input. Hydrological, chemical, and biological characteristics of these ecosystems have been monitored since 1977. Both sites experienced the second worst drought of the 20th century followed by the wettest period in more than a century. At Cottonwood Lake, plants that invaded the dry wetlands during the drought were flooded during the wet period and became a food source for animals. This resulted in successive substantial population increases and declines of plankton, invertebrates, amphibians and waterfowl. Substantial groundwater input buffered the lakes and wetlands in the Shingobee area against the changing water conditions. Only subtle changes in water chemistry and plankton populations were observed during the transition from drought to deluge.

IAHS-AISH Publication↗
USGS1996

Changes in atmospheric circulation patterns affect midcontinent wetlands sensitive to climate

Twenty-seven years of data from midcontinent wetlands indicate that the response of these wetlands to extremes in precipitation-drought and deluge-persists beyond the extreme events. Chemical changes transcend such simple relations as increased salinity during dry periods because drought provides mechanisms for removal of salt by deflation and seepage to groundwater. Inundation of vegetation zones including rooted or floating mats of cattail (Typha glauca) can stimulate sulfate reduction and shift the anion balance from sulfate to bicarbonate dominance. Disruptions in the circulation of moisture-laden air masses over the midcontinent, as in the drought of 1988 and the deluge of 1993, have a major effect on these wetlands, which are representatives of the primary waterfowl breeding habitat of the continent.

Limnology and Oceanography↗