Kolja Rotzoll
Kolja Rotzoll is a hydrologist with the Pacific Islands Water Science Center in Honolulu, Hawaiʻi.
Kolja Rotzoll is a hydrologist with a focus on combining coastal processes and hydrology. His expertise is in:
- numerical groundwater-flow and transport modeling of island aquifers (SUTRA, SEAWAT, MODFLOW with SWI2)
- soil-water balance modeling to estimate spatially distributed recharge (SWB2)
- time-series analysis of coastal groundwater levels to estimate hydraulic properties, impacts of sea-level rise, and other hydrological processes in Hawai‘i and Guam
- script-based approach to model-file generation, data analysis, and presentation (Python, MATLAB)
Education
PhD, Geology and Geophysics, University of Hawai‘i at Mānoa, 2007
MS, Coastal Geosciences and Engineering, University of Kiel, Germany, 2001
BS, Geography, University of Kiel, Germany, 1999
Professional Experience
Hydrologist, USGS Pacific Islands Water Science Center, Honolulu, Hawai‘i, 2019–present
Post-doctorate Researcher, Water Resources Research Center, University of Hawai‘i, 2008–2019
Research Assistant, Water Resources Research Center, University of Hawai‘i, 2002–2007
Research Assistant, Coastal Geology, University of Kiel, Germany, 2000–2001
Science and Products
MODFLOW-2005 and SWI2 models for assessing groundwater and surface-water interactions in the Heeia Watershed, Oahu, Hawaii
Resource managers and users seek information that can be used to balance the needs of competing uses of groundwater and streamflow in the Heeia watershed, Oahu. A previously constructed steady-state numerical groundwater-flow model for the island of Oahu, Hawaii (https://doi.org/10.3133/sir20205126) using MODFLOW-2005 with the Seawater Intrusion (SWI2) package was used to examine the effects of wi
MODFLOW-2005 and SWI2 models for assessing groundwater availability scenarios in volcanic aquifers on Kauai, Oahu, and Maui, Hawaii
Previously constructed steady-state numerical groundwater-flow models for the islands of Kauai, Oahu, and Maui, Hawaii (https://doi.org/10.3133/sir20205126) using MODFLOW-2005 with the Seawater Intrusion (SWI2) package, were used to examine the consequences of historical and plausible future withdrawals and changes in recharge. The volcanic aquifers of the Hawaiian Islands supply water to 1.46 mil
Mean annual water-budget components for Oahu, Hawaii, for future-climate conditions, CMIP5 RCP8.5 2041-70 scenario rainfall and 2010 land cover
This shapefile represents the spatial distribution of mean annual water-budget components, in inches, for the island of Oahu, Hawaii for a projected future-climate condition representative of phase 5 of the Coupled Model Intercomparison Project (CMIP5) Representative Concentration Pathway 8.5 (RCP8.5) 2041-70 scenario climate and 2010 land cover, as described in USGS Professional Paper (PP) 1876 b
SUTRA model used to evaluate long-term groundwater availability in the Waihee, Iao, and Waikapu aquifer systems, Maui, Hawaii
Groundwater levels have declined since the 1940s in the Wailuku area of central Maui, Hawaii,
on the eastern flank of West Maui volcano, mainly in response to increased groundwater
withdrawals. Available data since the 1980s also indicate a thinning of the freshwater lens and an
increase in chloride concentrations of pumped water from production wells. These trends,
combined with projected inc
MODFLOW-2005 and SWI2 models for assessing groundwater availability in the volcanic aquifers of Kauai, Oahu, and Maui, Hawaii
Steady-state numerical groundwater-flow models were constructed for the
islands of Kaua'i, O'ahu, and Maui, Hawai'i. Separate models were created
for each island using MODFLOW-2005 (Harbaugh, 2005) with the Seawater
Intrusion (SWI2) package (Bakker and others, 2013), which allows simulation
of freshwater and saltwater in ocean-island aquifers. The purpose of the models
is to enable quantifica
Filter Total Items: 19
Groundwater and surface-water interactions in the He‘eia watershed, O‘ahu, Hawai‘i—Insights from analysis of historical data and numerical groundwater-model simulations
He‘eia and ‘Ioleka‘a Streams in the He‘eia watershed on O‘ahu, Hawai‘i, receive substantial discharge from dike-impounded groundwater. Previous studies indicated that groundwater withdrawals from the watershed affect streamflow. Resource managers and users seek information that can be used to balance the needs of competing uses of groundwater and streamflow in the watershed.In this study, analyses
Authors
Scot K. Izuka, Heidi L. Kāne, Kolja Rotzoll
Availability of groundwater from the volcanic aquifers of the Hawaiian Islands
The islands of Hawaiʻi were built by basaltic shield volcanoes in the Pacific Ocean. These volcanoes formed aquifers that supply hundreds of millions of gallons of fresh water per day to the islands’ residents and diverse industries. Groundwater discharge from the volcanic aquifers to streams and the coast also supports traditional practices and ecosystems. The aquifers' capacity to yield fresh gr
Authors
Scot K. Izuka, Kolja Rotzoll
Volcanic aquifers of Hawaiʻi—Contributions to assessing groundwater availability on Kauaʻi, Oʻahu, and Maui
The volcanic aquifers of the Hawaiian Islands supply water to 1.46 million residents, diverse industries, and a large component of the U.S. military in the Pacific. Groundwater also supplies fresh water that supports ecosystems in streams and near the coast. Hawaii’s aquifers are remarkably productive given their small size, but the capacity of the islands to store fresh groundwater is limited bec
Authors
Scot K. Izuka, Kolja Rotzoll
Long-term groundwater availability in the Waihe‘e, ‘Īao, and Waikapū aquifer systems, Maui, Hawai‘i
Groundwater levels have declined since the 1940s in the Wailuku area of central Maui, Hawai‘i, on the eastern flank of West Maui volcano, mainly in response to increased groundwater withdrawals. Available data since the 1980s also indicate a thinning of the freshwater lens and an increase in chloride concentrations of pumped water from production wells. These trends, combined with projected increa
Authors
Kolja Rotzoll, Delwyn S. Oki, Adam G. Johnson, William R. Souza
The Hawai'i groundwater recharge tool
This article discusses the design and implementation of the Hawai’i Groundwater
Recharge Tool, an application for providing data and analyses of the impacts
of land-cover modifications and changes in precipitation on groundwater-recharge
rates for the island of O’ahu. This application uses simulation data based on a set of
29 land-cover types and 2 precipitation conditions to provide users with re
Authors
Jared H. McLean, Sean B. Cleveland, Kolja Rotzoll, Scot K. Izuka, Jason Leigh, Gwen A. Jacobs, Ryan Theriot
Volcanic Aquifers of Hawai‘i—Construction and calibration of numerical models for assessing groundwater availability on Kaua‘i, O‘ahu, and Maui
Steady-state numerical groundwater-flow models were constructed for the islands of Kaua‘i, O‘ahu, and Maui to enable quantification of the hydrologic consequences of withdrawals and other stresses that can place limits on groundwater availability. The volcanic aquifers of Hawai‘i supply nearly all drinking water for the islands’ residents, freshwater for diverse industries, and natural discharge t
Authors
Scot K. Izuka, Kolja Rotzoll, Tracy Nishikawa
Numerical simulation of groundwater availability in central Moloka‘i, Hawai‘i
Since the 1990s, increased chloride concentrations of water pumped from wells (much of which is used for drinking water) and the effects of withdrawals on groundwater-dependent ecosystems have led to concerns over groundwater availability on the island of Molokaʻi, Hawaiʻi. An improved understanding of the hydrologic effects of proposed groundwater withdrawals is needed to ensure effective managem
Authors
Delwyn S. Oki, John A. Engott, Kolja Rotzoll
The ‘Ike Wai Hawai‘i groundwater recharge tool
This paper discusses the design and implementation
of the ‘Ike Wai Hawai‘i Groundwater Recharge Tool, an
application for providing data and analyses of the impacts of
land-cover and climate modifications on groundwater-recharge
rates for the island of O‘ahu. This application uses simulation
data based on a set of 29 land-cover types and two rainfall
scenarios to provide users with real-time rechar
Authors
Jared H. McLean, Sean B. Cleaveland, Kolja Rotzoll, Scot K. Izuka, Jason Leigh, Gwen A. Jacobs, Ryan Theriot
Estimated groundwater recharge from a water-budget model incorporating selected climate projections, Island of Maui, Hawai‘i
Demand for freshwater on the Island of Maui is expected to increase by 45 percent between 2015 and 2035. Groundwater availability on Maui is affected by changes in climate and agricultural irrigation. To evaluate the availability of fresh groundwater under projected future climate conditions and changing agricultural irrigation practices, estimates of groundwater recharge are needed. A water-budge
Authors
Alan Mair, Adam G. Johnson, Kolja Rotzoll, Delwyn S. Oki
Enabling real-time user interaction for decision support: Experiences extending a local agave platform metadata service
The University of Hawai'i Information Technology Services Cyber-infrastructure team in partnership with the United States Geological Survey developed the Hawai'i groundwater recharge tool, a decision support tool, as part of the 'Ike Wai Gateway to support water sustainability research for the state of Hawai'i. To enable the development of the tool within the existing University of Hawai'i Agave p
Authors
Sean B. Cleveland, Jared H. McClean, Kolja Rotzoll, Scot K. Izuka, Gwen A. Jacobs
Hawai‘i Groundwater Recharge Tool
The Hawai‘i Groundwater Recharge Tool allows users to evaluate the potential effects of land-cover and climate changes on groundwater recharge. This website provides a baseline estimate of recharge representing recent conditions of precipitation (1978–2008 average) and land cover (2010). Users can change land cover and rainfall conditions to evaluate the effects on groundwater recharge. Results wi
Authors
Jared H. McLean, Kolja Rotzoll, Sean B. Cleaveland, Scot K. Izuka
Comparison of a simple hydrostatic and a data-intensive 3D numerical modeling method of simulating sea-level rise induced groundwater inundation for Honolulu, Hawai'i, USA
Groundwater inundation (GWI) is a particularly challenging consequence of sea-level rise (SLR), as it progressively inundates infrastructure located above and below the ground surface. Paths of flooding by GWI differ from other types of SLR flooding (i.e., wave overwash, storm-drain backflow) such that it is more difficult to mitigate, and thus requires a separate set of highly innovative adaptati
Authors
Shellie Habel, Charles H. Fletcher, Kolja Rotzoll, Aly I. El-Kadi, Delwyn S. Oki
Science and Products
MODFLOW-2005 and SWI2 models for assessing groundwater and surface-water interactions in the Heeia Watershed, Oahu, Hawaii
Resource managers and users seek information that can be used to balance the needs of competing uses of groundwater and streamflow in the Heeia watershed, Oahu. A previously constructed steady-state numerical groundwater-flow model for the island of Oahu, Hawaii (https://doi.org/10.3133/sir20205126) using MODFLOW-2005 with the Seawater Intrusion (SWI2) package was used to examine the effects of wi
MODFLOW-2005 and SWI2 models for assessing groundwater availability scenarios in volcanic aquifers on Kauai, Oahu, and Maui, Hawaii
Previously constructed steady-state numerical groundwater-flow models for the islands of Kauai, Oahu, and Maui, Hawaii (https://doi.org/10.3133/sir20205126) using MODFLOW-2005 with the Seawater Intrusion (SWI2) package, were used to examine the consequences of historical and plausible future withdrawals and changes in recharge. The volcanic aquifers of the Hawaiian Islands supply water to 1.46 mil
Mean annual water-budget components for Oahu, Hawaii, for future-climate conditions, CMIP5 RCP8.5 2041-70 scenario rainfall and 2010 land cover
This shapefile represents the spatial distribution of mean annual water-budget components, in inches, for the island of Oahu, Hawaii for a projected future-climate condition representative of phase 5 of the Coupled Model Intercomparison Project (CMIP5) Representative Concentration Pathway 8.5 (RCP8.5) 2041-70 scenario climate and 2010 land cover, as described in USGS Professional Paper (PP) 1876 b
SUTRA model used to evaluate long-term groundwater availability in the Waihee, Iao, and Waikapu aquifer systems, Maui, Hawaii
Groundwater levels have declined since the 1940s in the Wailuku area of central Maui, Hawaii,
on the eastern flank of West Maui volcano, mainly in response to increased groundwater
withdrawals. Available data since the 1980s also indicate a thinning of the freshwater lens and an
increase in chloride concentrations of pumped water from production wells. These trends,
combined with projected inc
MODFLOW-2005 and SWI2 models for assessing groundwater availability in the volcanic aquifers of Kauai, Oahu, and Maui, Hawaii
Steady-state numerical groundwater-flow models were constructed for the
islands of Kaua'i, O'ahu, and Maui, Hawai'i. Separate models were created
for each island using MODFLOW-2005 (Harbaugh, 2005) with the Seawater
Intrusion (SWI2) package (Bakker and others, 2013), which allows simulation
of freshwater and saltwater in ocean-island aquifers. The purpose of the models
is to enable quantifica
Filter Total Items: 19
Groundwater and surface-water interactions in the He‘eia watershed, O‘ahu, Hawai‘i—Insights from analysis of historical data and numerical groundwater-model simulations
He‘eia and ‘Ioleka‘a Streams in the He‘eia watershed on O‘ahu, Hawai‘i, receive substantial discharge from dike-impounded groundwater. Previous studies indicated that groundwater withdrawals from the watershed affect streamflow. Resource managers and users seek information that can be used to balance the needs of competing uses of groundwater and streamflow in the watershed.In this study, analyses
Authors
Scot K. Izuka, Heidi L. Kāne, Kolja Rotzoll
Availability of groundwater from the volcanic aquifers of the Hawaiian Islands
The islands of Hawaiʻi were built by basaltic shield volcanoes in the Pacific Ocean. These volcanoes formed aquifers that supply hundreds of millions of gallons of fresh water per day to the islands’ residents and diverse industries. Groundwater discharge from the volcanic aquifers to streams and the coast also supports traditional practices and ecosystems. The aquifers' capacity to yield fresh gr
Authors
Scot K. Izuka, Kolja Rotzoll
Volcanic aquifers of Hawaiʻi—Contributions to assessing groundwater availability on Kauaʻi, Oʻahu, and Maui
The volcanic aquifers of the Hawaiian Islands supply water to 1.46 million residents, diverse industries, and a large component of the U.S. military in the Pacific. Groundwater also supplies fresh water that supports ecosystems in streams and near the coast. Hawaii’s aquifers are remarkably productive given their small size, but the capacity of the islands to store fresh groundwater is limited bec
Authors
Scot K. Izuka, Kolja Rotzoll
Long-term groundwater availability in the Waihe‘e, ‘Īao, and Waikapū aquifer systems, Maui, Hawai‘i
Groundwater levels have declined since the 1940s in the Wailuku area of central Maui, Hawai‘i, on the eastern flank of West Maui volcano, mainly in response to increased groundwater withdrawals. Available data since the 1980s also indicate a thinning of the freshwater lens and an increase in chloride concentrations of pumped water from production wells. These trends, combined with projected increa
Authors
Kolja Rotzoll, Delwyn S. Oki, Adam G. Johnson, William R. Souza
The Hawai'i groundwater recharge tool
This article discusses the design and implementation of the Hawai’i Groundwater
Recharge Tool, an application for providing data and analyses of the impacts
of land-cover modifications and changes in precipitation on groundwater-recharge
rates for the island of O’ahu. This application uses simulation data based on a set of
29 land-cover types and 2 precipitation conditions to provide users with re
Authors
Jared H. McLean, Sean B. Cleveland, Kolja Rotzoll, Scot K. Izuka, Jason Leigh, Gwen A. Jacobs, Ryan Theriot
Volcanic Aquifers of Hawai‘i—Construction and calibration of numerical models for assessing groundwater availability on Kaua‘i, O‘ahu, and Maui
Steady-state numerical groundwater-flow models were constructed for the islands of Kaua‘i, O‘ahu, and Maui to enable quantification of the hydrologic consequences of withdrawals and other stresses that can place limits on groundwater availability. The volcanic aquifers of Hawai‘i supply nearly all drinking water for the islands’ residents, freshwater for diverse industries, and natural discharge t
Authors
Scot K. Izuka, Kolja Rotzoll, Tracy Nishikawa
Numerical simulation of groundwater availability in central Moloka‘i, Hawai‘i
Since the 1990s, increased chloride concentrations of water pumped from wells (much of which is used for drinking water) and the effects of withdrawals on groundwater-dependent ecosystems have led to concerns over groundwater availability on the island of Molokaʻi, Hawaiʻi. An improved understanding of the hydrologic effects of proposed groundwater withdrawals is needed to ensure effective managem
Authors
Delwyn S. Oki, John A. Engott, Kolja Rotzoll
The ‘Ike Wai Hawai‘i groundwater recharge tool
This paper discusses the design and implementation
of the ‘Ike Wai Hawai‘i Groundwater Recharge Tool, an
application for providing data and analyses of the impacts of
land-cover and climate modifications on groundwater-recharge
rates for the island of O‘ahu. This application uses simulation
data based on a set of 29 land-cover types and two rainfall
scenarios to provide users with real-time rechar
Authors
Jared H. McLean, Sean B. Cleaveland, Kolja Rotzoll, Scot K. Izuka, Jason Leigh, Gwen A. Jacobs, Ryan Theriot
Estimated groundwater recharge from a water-budget model incorporating selected climate projections, Island of Maui, Hawai‘i
Demand for freshwater on the Island of Maui is expected to increase by 45 percent between 2015 and 2035. Groundwater availability on Maui is affected by changes in climate and agricultural irrigation. To evaluate the availability of fresh groundwater under projected future climate conditions and changing agricultural irrigation practices, estimates of groundwater recharge are needed. A water-budge
Authors
Alan Mair, Adam G. Johnson, Kolja Rotzoll, Delwyn S. Oki
Enabling real-time user interaction for decision support: Experiences extending a local agave platform metadata service
The University of Hawai'i Information Technology Services Cyber-infrastructure team in partnership with the United States Geological Survey developed the Hawai'i groundwater recharge tool, a decision support tool, as part of the 'Ike Wai Gateway to support water sustainability research for the state of Hawai'i. To enable the development of the tool within the existing University of Hawai'i Agave p
Authors
Sean B. Cleveland, Jared H. McClean, Kolja Rotzoll, Scot K. Izuka, Gwen A. Jacobs
Hawai‘i Groundwater Recharge Tool
The Hawai‘i Groundwater Recharge Tool allows users to evaluate the potential effects of land-cover and climate changes on groundwater recharge. This website provides a baseline estimate of recharge representing recent conditions of precipitation (1978–2008 average) and land cover (2010). Users can change land cover and rainfall conditions to evaluate the effects on groundwater recharge. Results wi
Authors
Jared H. McLean, Kolja Rotzoll, Sean B. Cleaveland, Scot K. Izuka
Comparison of a simple hydrostatic and a data-intensive 3D numerical modeling method of simulating sea-level rise induced groundwater inundation for Honolulu, Hawai'i, USA
Groundwater inundation (GWI) is a particularly challenging consequence of sea-level rise (SLR), as it progressively inundates infrastructure located above and below the ground surface. Paths of flooding by GWI differ from other types of SLR flooding (i.e., wave overwash, storm-drain backflow) such that it is more difficult to mitigate, and thus requires a separate set of highly innovative adaptati
Authors
Shellie Habel, Charles H. Fletcher, Kolja Rotzoll, Aly I. El-Kadi, Delwyn S. Oki