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
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: 16
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
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
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
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
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
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
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
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
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
Volcanic aquifers of Hawai‘i—Hydrogeology, water budgets, and conceptual models
Hawai‘i’s aquifers have limited capacity to store fresh groundwater because each island is small and surrounded by saltwater. Saltwater also underlies much of the fresh groundwater. Fresh groundwater resources are, therefore, particularly vulnerable to human activity, short-term climate cycles, and long-term climate change. Availability of fresh groundwater for human use is constrained by the degr
Spatially distributed groundwater recharge estimated using a water-budget model for the Island of Maui, Hawai`i, 1978–2007
Demand for freshwater on the Island of Maui is expected to grow. To evaluate the availability of fresh groundwater, estimates of groundwater recharge are needed. A water-budget model with a daily computation interval was developed and used to estimate the spatial distribution of recharge on Maui for average climate conditions (1978–2007 rainfall and 2010 land cover) and for drought conditions (199
Spatially distributed groundwater recharge for 2010 land cover estimated using a water-budget model for the Island of O‘ahu, Hawai‘i
Owing mainly to projected population growth, demand for freshwater on the Island of Oʻahu is expected to increase by about 26 percent between 2010 and 2030, according to the City and County of Honolulu. Estimates of groundwater recharge are needed to evaluate the availability of fresh groundwater. For this study, a water-budget model with a daily computation interval was developed and used to esti
Science and Products
- Data
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 incMODFLOW-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 - Publications
Filter Total Items: 16
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 increaThe 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 reVolcanic 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 tNumerical 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 managemThe ‘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 recharEstimated 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-budgeEnabling 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 pHawai‘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 wiComparison 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 adaptatiVolcanic aquifers of Hawai‘i—Hydrogeology, water budgets, and conceptual models
Hawai‘i’s aquifers have limited capacity to store fresh groundwater because each island is small and surrounded by saltwater. Saltwater also underlies much of the fresh groundwater. Fresh groundwater resources are, therefore, particularly vulnerable to human activity, short-term climate cycles, and long-term climate change. Availability of fresh groundwater for human use is constrained by the degrSpatially distributed groundwater recharge estimated using a water-budget model for the Island of Maui, Hawai`i, 1978–2007
Demand for freshwater on the Island of Maui is expected to grow. To evaluate the availability of fresh groundwater, estimates of groundwater recharge are needed. A water-budget model with a daily computation interval was developed and used to estimate the spatial distribution of recharge on Maui for average climate conditions (1978–2007 rainfall and 2010 land cover) and for drought conditions (199Spatially distributed groundwater recharge for 2010 land cover estimated using a water-budget model for the Island of O‘ahu, Hawai‘i
Owing mainly to projected population growth, demand for freshwater on the Island of Oʻahu is expected to increase by about 26 percent between 2010 and 2030, according to the City and County of Honolulu. Estimates of groundwater recharge are needed to evaluate the availability of fresh groundwater. For this study, a water-budget model with a daily computation interval was developed and used to esti