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Robert W. Dudley

Publications and source records attributed to Robert W. Dudley.

83 records · Page 5Linked to original sources
USGS2003

Historical Dates of Ice-Affected Flows for 18 Rivers in New England

Historical dates of ice-affected flows for 18 rivers in New England were compiled and are presented in this report. The length of this record for the rivers ranges from 48 to 71 years, with an average of 62 years. The minimum number of days of ice-affected flow in a water year (October 1 to September 30) ranged from zero on three rivers in south-coastal Maine and coastal New Hampshire to 110 on the Allagash River in northern Maine. The maximum number of days of ice-affected flow in a water year ranged from 106 on the Royal River in south-coastal Maine to 171 on the Allagash River in northern Maine. Six streamflow-< gaging stations in Maine, New Hampshire, and Vermont had their latest days of ice-affected flow in the spring of 1939.

Open-File Report↗
USGS2002

Trends in Streamflow, River Ice, and Snowpack for Coastal River Basins in Maine During the 20th Century

Trends over the 20th Century were examined in streamflow, river ice, and snowpack for coastal river basins in Maine. Trends over time were tested in the timing and magnitude of seasonal river flows, the occurrence and duration of river ice, and changes in snowpack depth, equivalent water content, and density. Significant trends toward earlier spring peak flow and earlier center-of-volume runoff dates were found in the extended streamflow record spanning 1906-21 and 1929-2000. Only one of the six coastal rivers in the study analyzed for trends in cumulative runoff had a significant change in total annual runoff volume. Last spring river-ice-off dates at most coastal streamflow-gaging stations examined are trending to earlier dates. Trends in later fall initial onset of ice also are evident, although these trends are significant at fewer stations than that observed for ice-off dates. Later ice-on dates in the fall and (or) earlier ice-off dates in the spring contribute to a statistically significant decrease over time in the total number of days of ice occurrence at most gaging stations on coastal rivers in Maine. The longest, most complete snow records in coastal Maine indicate an increase in snow density for the March 1 snow-survey date during the last 60 years. The historical trends in streamflow, ice, and snow are all consistent with an earlier onset of hydrologic spring conditions in coastal Maine.

Water-Resources Investigations Report↗
USGS2002

Historical trend in ice thickness on the Piscataquis River in central Maine.

We analyzed a long-term record of ice thickness on the Piscataquis River in central Maine to determine whether there were temporal trends that were associated with climate warming. Trends in ice thickness were compared and correlated with regional time series of winter air temperature, heating degree days (HDD) , date of river ice-out, seasonal center-of-volume date (SCVD) (date on which half of the stream runoff volume during the period 1 Jan and 31 May has occurred), water temperature, and lake ice-out date. All of these variables except lake ice-out date showed significant temporal trends during the 20 th century. Average ice thickness around 28 Feb. decreased by about 23 cm from 1912 to 2001. Over the period 1900 to 1999, winter air temperature increased by 1.7 ˚C and HDD decreased by about 7.5%. Final ice-out date on the Piscataquis River occurred earlier (advanced), by 0.23 days yr –1 over the period 1931 to 2002. The SCVD advanced by 0.11 days yr –1 over the period 1903 to 2001. Ice thickness was significantly correlated with winter air temperature, HDD, river ice-out, and SCVD (P-value < 0.01). These systematic temporal trends in multiple hydrologic indicator variables indicate a coherent response to climate forcing.

Maine↗
USGS2001

Borehole geophysical data from Eastland Woolen Mill Superfund site, Corinna, Maine, March 1999

Borehole-geophysical data were collected in cooperation with the U.S. Environmental Protection Agency in seven bedrock wells at the Eastland Woolen Mill Superfund site, Penobscot County, Corinna, Maine, in March, 1999. The data were collected as part of a reconnaissance investigation to provide information needed to address concerns about the distribution and fate of contaminants in ground-water at the site. The borehole geophysical data were also needed to guide subsequent data collection associated with the development of a remediation workplan. The borehole geophysical logs collected included: natural gamma, caliper, fluid temperature, fluid conductivity, electromagnetic conductivity, electromagnetic resistivity, spontaneous potential, and single-point resistivity.

Maine↗
USGS2001

Simulated Ground-Water-Flow Responses to Geohydrologic Characteristics, Corinna, Maine

Ground-water-flow simulations of an idealization of surficial and bedrock aquifers of the East Branch Sebasticook River Valley, in Corinna, Maine, were done to test the effects of known or hypothesized geohydrologic characteristics on the local and regional ground-water-flow system. The purpose of the simulations was to develop a better understanding of the aquifer system to aid in planning for the eventual removal of contaminants. The effects of eight individual geohydrologic characteristics on simulated ground-water flow were compared with a base simulation. The eight geohydrologic characteristics simulated were (1) a northeast-southwest transmissive bedding- plane fracture system, (2) a northwest-southeast valley floor transmissive fracture zone, (3) an upper weathered bedrock transmissive zone, (4) river- and pond-stage changes, (5) river- and pondbottom conductivity changes, (6) multiple withdrawals, (7) a combination of some of these characteristics, and (8) relocation of a pond-outlet stream. The effects of many of the analyzed characteristics are slight or relatively minor with respect to a simulated bedrock aquifer. The simulated ground-water flow through the bedrock aquifer is a small percentage (about 1 percent) of the total flow to the system; therefore, the effects of most geohydrologic characteristics simulated are minimal in the aquifer. Some characteristics, for example, anisotropy imparted on the bedrock system by a northeast-southwest transmissive bedding-plane fracture system, strongly affect flow patterns in the bedrock aquifer but not in the surficial aquifer. Individually, most of the geohydrologic characteristics evaluated only slightly affect the groundwater flow in the bedrock; however, in combination, these characteristics significantly affected the entire simulated ground-water-flow system. Domestic or remedial withdrawal wells generally had little effect on the regional ground-water-flow system but did affect the local ground-water-flow patterns, which could affect the extent and movement of contaminants.

Water-Resources Investigations Report↗
USGS2001

Evaluation of the Effects of Development on Peak-Flow Hydrographs for Collyer Brook, Maine

The development of former agricultural or forested lands creates more impervious areas and drainage improvements that can increase the volume of runoff and decrease infiltration and ground-water recharge in a watershed. Drainage improvements also can improve the conveyance of runoff, decreasing the time of rise to peak flow between the start of a rainfall event and the peak surface-water runoff, and likewise decreasing the duration of the peak-flow event. The watershed of Collyer Brook in southern Maine was studied to evaluate the effect of land-use changes on peakflow hydrographs because of the known development in the area during the past 35 years and the availability of aerial photos and streamflow data for this time period. Although aerial photography indicates that suburban development has increased in the watershed between 1964 and 1999, the overall effect of suburbanization on rainfall-runoff processes in the watershed did not produce a statistically detectable change in the peak-flow hydrographs for Collyer Brook.

Water-Resources Investigations Report↗
USGS2001

Composition and Distribution of Streambed Sediments in the Penobscot River, Maine, May 1999

Sediment samples were collected and geophysical surveys were run along 50 miles of the Penobscot River, Maine, in the spring of 1999 to produce maps that describe the composition and distribution of streambed sediments for selected areas in the river channel. The objective of the sediment survey was to locate areas along the river where fine-grained, easily transportable sediment types were deposited between Old Town and Medway, Maine. These data can be used to design future sediment-sampling programs to assess the quality of streambed sediments and evaluate the health of the Penobscot River. This report describes the results of the sediment survey and the methods used to collect, analyze, and interpret the data used to create maps of streambed-sediment types in the study area. Deposits of fine-grained sediments (mud and sand) are scattered along the shorelines of the mainland and the islands and at the downstream ends of islands and at the mouths of brooks and streams. The most extensive depositional areas were found in the Mattaseunk Dam impoundment near Medway. The main areas of the river channel consist primarily of gravel, sand, and rock.

Water-Resources Investigations Report↗
USGS2001

Water budget for Sebago Lake, Maine, 1996-99

Annual water budgets were developed for Sebago Lake in southwestern Maine. The inflow components of the water budget are direct precipitation to the surface of the lake and surface-water inflow. Mean annual inflow to Sebago Lake during water years 1996-99 was 35,100 million cubic feet. The outflow components of the water budget are evaporation from the surface of the lake, municipal water-supply withdrawals by the Portland Water District, and surface-water outflow. Mean annual outflow during water years 1996-99 was 28,200 million cubic feet. The two largest components of the water budgets are the surface-water components - surface-water inflow was 84.0 percent of the mean annual inflow budget and surface-water outflow was 87.3 percent of the mean annual outflow budget. Changes in lake storage also were included in the water budgets. The sum of inflow minus outflow volumes, adjusted for changes in lake storage, do not balance for each water year. This remainder volume is the residual in the water budget calculation. The mean annual residual for the 4 years is 5,860 million cubic feet and is relatively consistent in magnitude and sign (positive) each water year, indicating either a systematic overestimation of inflows to or underestimation of outflows from Sebago Lake. The residual also could be partially composed of ground-water flow, a budget component not accounted for in this study. Errors associated with budgeting precipitation, evaporation, and net changes in storage are relatively small. The largest potential errors in calculating the water budget for Sebago Lake are those associated with surface-water inflow and outflow, because they are the two largest elements of the budget, and ground-water flow (net in or out) because it was not computed.

Maine↗
USGS2000

Streamflow Statistics for the Narraguagus River at Cherryfield, Maine

Streamflow data have been collected for the Narraguagus River from 1948 to the present (2000) at the U.S. Geological Survey (USGS) streamgaging station at Cherryfield, Maine. This report describes a study done by the USGS to determine streamflow statistics using the streamflow record at the Narraguagus River station for use in total water use management plans implemented by State and Federal agencies. Because the effect of changes in irrigation practices from 1993 to the present on streamflow in the Narraguagus basin is unknown and potentially significant, streamflow data after December 1992 were not used in the determination of the streamflow statistics. For the period 1948- 92, monthly median streamflows range from 93.0 ft3/s (August) to 1,000 ft3/s (April). The median streamflow for the selected period of record for all days (1948-92) is 302 ft3/s.

Open-File Report↗
USGS1999

Riverbed-sediment mapping in the Edwards Dam Impoundment on the Kennebec River, Maine by use of geophysical techniques

In July 1997, the Federal Energy Regulatory Commission (FERC) issued a Final Environmental Impact Statement recommending that the 162-year-old Edwards Dam on the Kennebec River in Augusta, Maine, be removed. The impoundment formed by Edwards Dam extends about 15 mi to the city of Waterville, near the confluence of the Sebasticook River with the Kennebec River. The impoundment has a surface area of 1,143 acres, a gross storage of approximately 740 million ft 3 , and a usable storage of about 184 million ft 3 (Stone and Webster, 1995a). According to FERC, removal of the 917-ft-long, 24-ft-high timber crib and concrete structure would restore 15 mi of riverine habitat, improve passage of ocean-migrating fish species native to the Kennebec River, and result in substantial recreational enhancements (Federal Energy Regulatory Commission, 1997). Because the removal of Edwards Dam would change the hydraulic characteristics of the river in the present-day impoundment, the potential transport of erodible, fine-grained sediment currently in the impoundment is a concern. Of particular concern is the erosion and transport of this sediment to areas downstream from the dam, a process that could introduce possible bacterial and chemical contamination and could impede river navigation as a result of sediment deposition. In an effort to build upon available information on the composition of the riverbed, the U.S. Geological Survey (USGS), in cooperation with the Maine State Planning Office, classified riverbed sediment types and mapped their areal extents in the lower (southern) half of the Edwards Dam impoundment. This report describes the methods used to collect and analyze the data used to create a map of sediment types in the Edwards Dam impoundment. The map is included with this report. Data used to map riverbed sediment types were also used to estimate the volume of observed mud and mud-containing sediment in the study area.

Maine↗