Geology topics

Nicholas W. Stasulis

Publications and source records attributed to Nicholas W. Stasulis.

3 recordsLinked to original sources

USGS2019

Preliminary stage and streamflow data at selected U.S. Geological Survey streamgages in New England for the floods of April 2019

The combination of rainfall and snowmelt in northern New England and rainfall in southern New England resulted in minor to major flooding from April 15 to 24, 2019, according to stage and streamflow data collected at 63 selected U.S. Geological Survey (USGS) streamgages. A typical USGS streamgage measures and records stream stage and estimates streamflow based on a relation (rating curve) of discrete measurements of streamflow and the recorded stage. USGS hydrographers were deployed during and after these storms to measure the streamflow of the flooded rivers and confirm streamgage rating curves. Preliminary Data Indicate... The National Weather Service flood stage was reached at 36 USGS streamgages selected for monitoring; the minor flood stage category was reached at 30 streamgages, moderate flood stage category at 5 streamgages, and major flood stage category at 1 streamgage. Peak streamflows for the period of record occurred at three streamgages in Maine. Of these, the peak at the St. John River at Ninemile Bridge, Maine streamgage was the highest in its 67-year period of record. A total of 30 streamgages—15 streamgages in Maine, 9 in Vermont, 4 in New Hampshire, and 1 each in Connecticut and Massachusetts—recorded peak streamflows within the top 10 for their period of record. Two of these streamgages, the Clyde River at Newport, Vermont and the Saco River at Cornish, Maine, have periods of record greater than 100 years. In total, USGS hydrographers made more than 210 streamflow measurements during the April 15–24 floods in New England.

Maine, Vermont, New Hampshire, Massachusetts, Rhod↗

USGS2018

Preliminary stage and streamflow data at selected U.S. Geological Survey streamgages in Maine and New Hampshire for the flood of October 30–31, 2017

Rainfall from a storm on October 24–27, 2017, and Tropical Storm Philippe on October 29–30, created conditions that led to flooding across portions of New Hampshire and western Maine. On the basis of streamflow data collected at 30 selected U.S. Geological Survey (USGS) streamgages in the Androscoggin River, Connecticut River, Merrimack River, and Saco River Basins, the storms caused minor to moderate flooding in those basins on October 30–31, 2017. During the storms, the USGS deployed hydrographers to take discrete measurements of streamflow. The measurements were used to confirm the stage-to-streamflow relation (rating curve) at the selected USGS streamgages. Following the storms, hydrographers documented high-water marks in support of indirect measurements of streamflow. Seven streamgages with greater than 50 years of streamflow data recorded preliminary streamflow peaks within the top five for the periods of record. Twelve streamgages recorded preliminary peak streamflows greater than an estimate of the 100-year streamflow based on drainage area.

Maine, New Hampshire↗

USGS2012

Relations among water levels, specific conductance, and depths of bedrock fractures in four road-salt-contaminated wells in Maine, 2007–9

Data on groundwater-level, specific conductance (a surrogate for chloride), and temperature were collected continuously from 2007 through 2009 at four bedrock wells known to be affected by road salts in an effort to determine the effects of road salting and fractures in bedrock that intersect the well at a depth below the casing on the presence of chloride in groundwater. Dissolved-oxygen data collected periodically also were used to make inferences about the interaction of fractures and groundwater flow. Borehole geophysical tools were used to determine the depths of fractures in each well that were actively contributing flow to the well, under both static and pumped conditions; sample- and measurement-depths were selected to correspond to the depths of these active fractures. Samples of water from the wells, collected at depths corresponding to active bedrock fractures, were analyzed for chloride concentration and specific conductance; from these analyses, a linear relation between chloride concentration and specific conductance was established, and continuous and periodic measurements of specific conductance were assumed to represent chloride concentration of the well water at the depth of measurement. To varying degrees, specific conductance increased in at least two of the wells during winter and spring thaws; the shallowest well, which also was closest to the road receiving salt treatment during the winter, exhibited the largest changes in specific conductance during thaws. Recharge events during summer months, long after application of road salt had ceased for the year, also produced increases in specific conductance in some of the wells, indicating that chloride which had accumulated or sequestered in the overburden was transported to the wells throughout the year. Geophysical data and periodic profiles of water quality along the length of each well’s borehole indicated that the greatest changes in water quality were associated with active fractures; in one case, high concentration of dissolved oxygen at the bottom of the well indicated the presence of a highly transmissive fracture that was in good connection with a surficial feature (stream or atmosphere). Data indicated that fractures have a substantial influence on the transport of chlorides to the subsurface; that elevated specific conductance occurred throughout the year, not just when road salts were applied; and that chloride contamination, as indicated by elevated specific conductance, may persist for years.

Maine↗