Geology topics

Research about Grand Rapids, Minnesota

Source-linked reports with geographic coverage including Grand Rapids, Minnesota.

5 recordsLinked to original sources

USGS2005

Simulated effects of water-level changes in the Mississippi River and Pokegama Reservoir on ground-water levels, Grand Rapids area, Minnesota

The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, used an existing, three-dimensional, numerical ground-water flow model (referred to as the calibrated model) to assess the effects of water-level changes in the Mississippi River and Pokegama Reservoir on ground-water levels in adjacent glaciofluvial aquifers in the Grand Rapids area of north-central Minnesota. Pokegama Reservoir consists of Pokegama Lake, Little Jay Gould Lake, Jay Gould Lake, Cut-off Lake, and Blackwater Lake. Water levels in the Pokegama Reservoir are regulated at Pokegama Dam on the Mississippi River west of Grand Rapids. A steady-state model was used, and simulations represent “worse-case” scenarios for the effects of lowering or raising the river and lake water levels. The simulated ground-water levels represent levels that would result if the river and lake stages permanently declined or rose by the specified amounts. Eight hypothetical scenarios were simulated by varying water levels in the Mississippi River and Pokegama Reservoir from values used in the calibrated model. In the simulations, water levels for the Mississippi River, riverine wetlands of the Mississippi River, and lakes of the Pokegama Reservoir were raised and lowered uniformly by 0.50, 1.00, 2.00, and 3.00 feet from calibrated water levels. The extent of aquifer water-level changes resulting from these river, wetland, and lake water-level changes varied because of the complex hydrogeology of the study area. A 1.00-foot decline in reservoir/river water levels caused a maximum simulated ground-water-level decline in the middle aquifer near Jay Gould and Little Jay Gould Lakes of 1.09 feet and a maximum simulated ground-water-level decline of 1.00 foot in the lower aquifer near Cut-off and Blackwater Lakes. The amount and extent of ground-water-level changes in the middle and lower aquifers can be explained by the thickness, extent, and connectivity of the aquifers. Surface-water/ground-water interactions near wetlands and lakes with water levels unchanged from the calibrated model resulted in small water-table altitude differences among the simulations. Results of the ground-water modeling indicate that lowering of the reservoir and river water levels by 1.00 foot likely will not substantially affect water levels in the middle and lower aquifers.

Minnesota↗

USGS2004

Simulation of ground-water flow in glaciofluvial aquifers in the Grand Rapids area, Minnesota

A calibrated steady-state, finite-difference, ground-waterflow model was constructed to simulate ground-water flow in three glaciofluvial aquifers, defined in this report as the upper, middle, and lower aquifers, in an area of about 114 mi2 surrounding the city of Grand Rapids in north-central Minnesota. The calibrated model will be used by Minnesota Department of Health and communities in the Grand Rapids area in the development of wellhead protection plans for their water supplies. The model was calibrated through comparison of simulated ground-water levels to measured static water levels in 351 wells, and comparison of simulated base-flow rates to estimated base-flow rates for reaches of the Mississippi and Prairie Rivers. Model statistics indicate that the model tends to overestimate ground-water levels. The root mean square errors ranged from +12.83 ft in wells completed in the upper aquifer to +19.10 ft in wells completed in the middle aquifer. Mean absolute differences between simulated and measured water levels ranged from +4.43 ft for wells completed in the upper aquifer to +9.25 ft for wells completed in the middle aquifer. Mean algebraic differences ranged from +9.35 ft for wells completed in the upper aquifer to +14.44 ft for wells completed in the middle aquifer, with the positive differences indicating that the simulated water levels were higher than the measured water levels. Percentage errors between simulated and estimated base-flow rates for the three monitored reaches all were less than 10 percent, indicating good agreement. Simulated ground-water levels were most sensitive to changes in general-head boundary conductance, indicating that this characteristic is the predominant model input variable controlling steady-state water-level conditions. Simulated groundwater flow to stream reaches was most sensitive to changes in horizontal hydraulic conductivity, indicating that this characteristic is the predominant model input variable controlling steady-state flow conditions.

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USGS1990

Effects of winter undernutrition on body composition and physiological profiles of white-tailed deer

We examined the effects of undernutrition and recovery on body composition and blood and urinary profiles of 6 captive white-tailed deer ( Odocoileus virginianus ) between 18 December 1984 and 3 May 1985. Deer were weighed, and blood and urine were collected every 2 weeks from 10 January to 3 May. At Weeks 2, 8, and 14, body composition was estimated by the dilution of tritiated water technique and standard predictive equations. Feed intake decreased and cumulative mass loss increased during nutritional restriction. Baseline body composition included 62.1 ± 0.9 (SE)% water, 11.9 ± 1.0% fat, 20.5 ± 0.7% protein, and 4.5 ± 0.0% ash. Percent protein loss was linearly related (r 2 = 0.91, P < 0.001) to percent mass loss. Peak mass loss from the beginning of the study (12.8 ± 2.0%) occurred at Week 12; estimated protein loss was 12.5%. Fat reserves were 85% depleted from Week 2 to Week 14. Elevated packed cell volume (PCV), serum calcium (Ca), cholesterol, triglycerides, and cortisol; and diminished serum urea nitrogen, thyroxine (T4), urinary urea nitrogen: creatinine and potassium: creatinine were associated with reduced food intake, mass loss, and decreases in body water, fat, and protein. Altered values of most of these blood and urinary characteristics reflected initiation of nutritional recovery after nutrition improved. Sequential data collection and the use of a combination of indices in blood or urine will yield the most useful assessments of animal nutrition and condition.

Minnesota↗

USGS1987

Winter fasting and refeeding effects on urine characteristics in white-tailed deer

The effects of dietary protein, fasting, and refeeding on urinary characteristics of 9 captive, female white-tailed deer ( Odocoileus virginianus ) were studied from 23 February to 3 May 1984. Urinary sodium (na) and potassium (K) were diminished in fasted deer after 2 and 4 weeks. Renal excretion of Na and K were lower, whereas urinary phosphorus (P) was higher in fasted deer compared to deer fed high protein-high energy (HPHE) diets. Urinary P excretion of the fasted deer was also greater than in a low protein-high energy (LPHE)-fed group. Urinary area excretion of fasted deer was similar to that of deer fed low and high protein diets. One fasted deer died during the study and exhibited notably high excretion of urea, Na, K, and calcium (Ca). No effects of the 2 levels of dietary protein on urinary characteristics were detected. Urinary Na:C and K:C ratios wer significantly correlated with Na and K intake. Urinalysis has potential as a sensitive means of monitoring the nutritional status of white-tailed deer. Data are presented as reference values for interpretation of data from deer under less controlled circumstances.

Minnesota↗

USGS1987

Effects of winter fasting and refeeding on white-tailed deer blood profiles

This study examined the effects of dietary protein, fasting, and refeeding on blood characteristics of 9 nonpregnant, female white-tailed deer ( Odocoileus virginianus ) in captivity from 23 February to 3 May 1984. Percent weight loss was greater in fasted deer than in deer fed diets of 2 crude protein levels. Fasting effects were also observed for hemoglobin (Hb), red blood cell (RBC) counts, packed cell volume (PCV), cholesterol, triglycerides, serum urea nitrogen (SUN), potassium (K), glucose, phosphorus (P), insulin, thyroxine (T4), and total protein (TP). Refeeding influenced cholesterol, sodium (Na), and calcium (Ca). Hemoglobin, PCV, Ca, P, and albumin varied with time in fasted deer. Changes over time in the fed deer occurred for several hematological and serum characteristics. Data are presented to serve as reference values for better understanding of data collected from free-ranging deer under less known conditions.

Minnesota↗