Leonard Orzol (Former Employee)
Science and Products
Klamath River Basin water-quality data
The Klamath River Basin stretches from the mountains and inland basins of south-central Oregon and northern California to the Pacific Ocean, spanning multiple climatic regions and encompassing a variety of ecosystems. Water quantity and water quality are important topics in the basin, because water is a critical resource for farming and municipal use, power generation, and for the support of wildl
Authors
Cassandra D. Smith, Stewart A. Rounds, Leonard L. Orzol
Ground water redox zonation near La Pine, Oregon: Relation to river position within the aquifer–riparian zone continuum
Increasing residential development since in the 1960s has lead to increases in nitrate concentrations in shallow ground water in parts of the 247 square mile study area near La Pine, Oregon. Denitrification is the dominant nitrate-removal process that occurs in suboxic ground water, and suboxic ground water serves as a barrier to transport of most nitrate in the aquifer. Oxic ground water, on the
Authors
Stephen R. Hinkle, David S. Morgan, Leonard L. Orzol, Danial J. Polette
Approach for delineation of contributing areas and zones of transport to selected public-supply wells using a regional ground-water flow model, Palm Beach County, Florida
Rapid urban development and population growth in Palm Beach County, Florida, have been accompanied with the need for additional freshwater withdrawals from the surficial aquifer system. To maintain water quality, County officials protect capture areas and determine zones of transport of municipal supply wells. A multistep process was used to help automate the delineation of wellhead protection are
Authors
R.A. Renken, R.D. Patterson, L.L. Orzol, Joann Dixon
Ground-water and water-chemistry data for the Willamette basin, Oregon
This report presents ground-water data collected and compiled as part of a study of the ground-water resources of the Willamette River Basin, Oregon. The report includes tabulated information and a location map for 1,234 field-located water wells and 6 springs, hydrographs showing water-level fluctuations during various time periods for 265 of the wells, borehole geophysical data for 16 wells, and
Authors
Leonard L. Orzol, Karl C. Wozniak, Tiffany R. Meissner, Douglas B. Lee
Evaluation of factors that influence estimated zones of transport for six municipal wells in Clark County, Washington
A ground-water flow model was used in conjunction with particle tracking to estimate zones of transport for six municipal well sites in Clark County, Washington. A zone of transport for a well is a three-dimensional volume within a ground-water system that contains all of the ground water that will discharge from that well within a specified time period. All of the zones of transport for a well co
Authors
L.L. Orzol, Margot Truini
Use of a ground-water flow model with particle tracking to evaluate ground-water vulnerability, Clark County, Washington
A ground-water flow model was used in conjunction with a particle-tracking program to demonstrate a method of evaluating ground-water vulnerability. The study area encompassed the part of the Portland Basin located in Clark County, Washington. A new computer program was developed that interfaces the particle-tracking program with a geographic information system (GIS). The GIS was used to display a
Authors
Daniel T. Snyder, James M. Wilkinson, Leonard L. Orzol
User's guide for MODTOOLS: Computer programs for translating data of MODFLOW and MODPATH into geographic information system files
MODTOOLS is a set of computer programs for translating data of the ground-water model, MODFLOW, and the particle-tracker, MODPATH, into a Geographic Information System (GIS). MODTOOLS translates data into a GIS software called ARC/INFO. MODFLOW is the recognized name for the U.S. Geological Survey Modular Three-Dimensional Finite-Difference Ground-Water Model. MODTOOLS uses the data arrays input t
Authors
Leonard L. Orzol
Use of a ground-water flow model with particle tracking to evaluate ground-water vulnerability, Clark County, Washington
A ground-water flow model was used in conjunction with particle tracking to evaluate ground-water vulnerability in Clark County, Washington. Using the particle-tracking program, particles were placed in every cell of the flow model (about 60,000 particles) and tracked backwards in time and space upgradient along flow paths to their recharge points. A new computer program was developed that interfa
Authors
D.T. Snyder, J.M. Wilkinson, L.L. Orzol
Modifications of the U.S. Geological Survey modular, finite-difference, ground-water flow model to read and write geographic information system files
This report documents modifications to the U.S. Geological Survey modular, three-dimensional, finite-difference, ground-water flow model, commonly called MODFLOW, so that it can read and write files used by a geographic information system (GIS). The modified model program is called MODFLOWARC.
Simulation programs such as MODFLOW generally require large amounts of input data and produce large amo
Authors
Leonard L. Orzol, Timothy S. McGrath
Flood hazards along the Toutle and Cowlitz rivers, Washington, from a hypothetical failure of Castle Lake blockage
A recent evaluation of groundwater and material in the blockage impounding Castle Lake shows that the blockage is potentially unstable against failure from piping due to heave and internal erosion when groundwater levels are seasonally high. There is also a remote possibility that a 6.8 or greater magnitude earthquake could occur in the Castle Lake area when groundwater levels are critically high.
Authors
Antonius Laenen, L.L. Orzol
Hydrologic hazards along Squaw Creek from a hypothetical failure of the glacial moraine impounding Carver Lake near Sisters, Oregon
A hydrologic hazard exists that could create a large-magnitude, but short-duration, flood in the Squaw Creek drainage and inundate areas in and around the community of Sisters, Oregon. There is a 1 to 5% probability that Carver Lake, located at elevation 7,800 ft above sea level on the east slope of South Sister mountain, Oregon, could catastrophically empty. At the U.S. Geological Survey gage (14
Authors
Antonius Laenen, K. M. Scott, J. E. Costa, L.L. Orzol
Science and Products
Klamath River Basin water-quality data
The Klamath River Basin stretches from the mountains and inland basins of south-central Oregon and northern California to the Pacific Ocean, spanning multiple climatic regions and encompassing a variety of ecosystems. Water quantity and water quality are important topics in the basin, because water is a critical resource for farming and municipal use, power generation, and for the support of wildl
Authors
Cassandra D. Smith, Stewart A. Rounds, Leonard L. Orzol
Ground water redox zonation near La Pine, Oregon: Relation to river position within the aquifer–riparian zone continuum
Increasing residential development since in the 1960s has lead to increases in nitrate concentrations in shallow ground water in parts of the 247 square mile study area near La Pine, Oregon. Denitrification is the dominant nitrate-removal process that occurs in suboxic ground water, and suboxic ground water serves as a barrier to transport of most nitrate in the aquifer. Oxic ground water, on the
Authors
Stephen R. Hinkle, David S. Morgan, Leonard L. Orzol, Danial J. Polette
Approach for delineation of contributing areas and zones of transport to selected public-supply wells using a regional ground-water flow model, Palm Beach County, Florida
Rapid urban development and population growth in Palm Beach County, Florida, have been accompanied with the need for additional freshwater withdrawals from the surficial aquifer system. To maintain water quality, County officials protect capture areas and determine zones of transport of municipal supply wells. A multistep process was used to help automate the delineation of wellhead protection are
Authors
R.A. Renken, R.D. Patterson, L.L. Orzol, Joann Dixon
Ground-water and water-chemistry data for the Willamette basin, Oregon
This report presents ground-water data collected and compiled as part of a study of the ground-water resources of the Willamette River Basin, Oregon. The report includes tabulated information and a location map for 1,234 field-located water wells and 6 springs, hydrographs showing water-level fluctuations during various time periods for 265 of the wells, borehole geophysical data for 16 wells, and
Authors
Leonard L. Orzol, Karl C. Wozniak, Tiffany R. Meissner, Douglas B. Lee
Evaluation of factors that influence estimated zones of transport for six municipal wells in Clark County, Washington
A ground-water flow model was used in conjunction with particle tracking to estimate zones of transport for six municipal well sites in Clark County, Washington. A zone of transport for a well is a three-dimensional volume within a ground-water system that contains all of the ground water that will discharge from that well within a specified time period. All of the zones of transport for a well co
Authors
L.L. Orzol, Margot Truini
Use of a ground-water flow model with particle tracking to evaluate ground-water vulnerability, Clark County, Washington
A ground-water flow model was used in conjunction with a particle-tracking program to demonstrate a method of evaluating ground-water vulnerability. The study area encompassed the part of the Portland Basin located in Clark County, Washington. A new computer program was developed that interfaces the particle-tracking program with a geographic information system (GIS). The GIS was used to display a
Authors
Daniel T. Snyder, James M. Wilkinson, Leonard L. Orzol
User's guide for MODTOOLS: Computer programs for translating data of MODFLOW and MODPATH into geographic information system files
MODTOOLS is a set of computer programs for translating data of the ground-water model, MODFLOW, and the particle-tracker, MODPATH, into a Geographic Information System (GIS). MODTOOLS translates data into a GIS software called ARC/INFO. MODFLOW is the recognized name for the U.S. Geological Survey Modular Three-Dimensional Finite-Difference Ground-Water Model. MODTOOLS uses the data arrays input t
Authors
Leonard L. Orzol
Use of a ground-water flow model with particle tracking to evaluate ground-water vulnerability, Clark County, Washington
A ground-water flow model was used in conjunction with particle tracking to evaluate ground-water vulnerability in Clark County, Washington. Using the particle-tracking program, particles were placed in every cell of the flow model (about 60,000 particles) and tracked backwards in time and space upgradient along flow paths to their recharge points. A new computer program was developed that interfa
Authors
D.T. Snyder, J.M. Wilkinson, L.L. Orzol
Modifications of the U.S. Geological Survey modular, finite-difference, ground-water flow model to read and write geographic information system files
This report documents modifications to the U.S. Geological Survey modular, three-dimensional, finite-difference, ground-water flow model, commonly called MODFLOW, so that it can read and write files used by a geographic information system (GIS). The modified model program is called MODFLOWARC.
Simulation programs such as MODFLOW generally require large amounts of input data and produce large amo
Authors
Leonard L. Orzol, Timothy S. McGrath
Flood hazards along the Toutle and Cowlitz rivers, Washington, from a hypothetical failure of Castle Lake blockage
A recent evaluation of groundwater and material in the blockage impounding Castle Lake shows that the blockage is potentially unstable against failure from piping due to heave and internal erosion when groundwater levels are seasonally high. There is also a remote possibility that a 6.8 or greater magnitude earthquake could occur in the Castle Lake area when groundwater levels are critically high.
Authors
Antonius Laenen, L.L. Orzol
Hydrologic hazards along Squaw Creek from a hypothetical failure of the glacial moraine impounding Carver Lake near Sisters, Oregon
A hydrologic hazard exists that could create a large-magnitude, but short-duration, flood in the Squaw Creek drainage and inundate areas in and around the community of Sisters, Oregon. There is a 1 to 5% probability that Carver Lake, located at elevation 7,800 ft above sea level on the east slope of South Sister mountain, Oregon, could catastrophically empty. At the U.S. Geological Survey gage (14
Authors
Antonius Laenen, K. M. Scott, J. E. Costa, L.L. Orzol