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
Filter Total Items: 21
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
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
Authors
Scot K. Izuka, John A. Engott, Kolja Rotzoll, Maoya Bassiouni, Adam G. Johnson, Lisa D. Miller, Alan Mair
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
Authors
Adam G. Johnson, John A. Engott, Maoya Bassiouni, Kolja Rotzoll
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
Authors
John A. Engott, Adam G. Johnson, Maoya Bassiouni, Scot K. Izuka, Kolja Rotzoll
Estimating hydraulic properties from tidal attenuation in the Northern Guam Lens Aquifer, territory of Guam, USA
Tidal-signal attenuations are analyzed to compute hydraulic diffusivities and estimate regional hydraulic conductivities of the Northern Guam Lens Aquifer, Territory of Guam (Pacific Ocean), USA. The results indicate a significant tidal-damping effect at the coastal boundary. Hydraulic diffusivities computed using a simple analytical solution for well responses to tidal forcings near the periphery
Authors
Kolja Rotzoll, Stephen B. Gingerich, John W. Jenson, Aly I. El-Kadi
Numerical simulation of flow in deep open boreholes in a coastal freshwater lens, Pearl Harbor Aquifer, O‘ahu, Hawai‘i
The Pearl Harbor aquifer in southern O‘ahu is one of the most important sources of freshwater in Hawai‘i. A thick freshwater lens overlays brackish and saltwater in this coastal aquifer. Salinity profiles collected from uncased deep monitor wells (DMWs) commonly are used to monitor freshwater-lens thickness. However, vertical flow in DMWs can cause the measured salinity to differ from salinity in
Authors
Kolja Rotzoll
Effects of groundwater withdrawal on borehole flow and salinity measured in deep monitor wells in Hawai'i: implications for groundwater management
Water-resource managers in Hawai`i rely heavily on salinity profiles from deep monitor wells to estimate the thickness of freshwater and the depth to the midpoint of the transition zone between freshwater and saltwater in freshwater-lens systems. The deep monitor wells are typically open boreholes below the water table and extend hundreds of feet below sea level. Because of possible borehole-flow
Authors
Kolja Rotzoll
Changes of freshwater-lens thickness in basaltic island aquifers overlain by thick coastal sediments
Freshwater-lens thickness and long-term changes in freshwater volume in coastal aquifers are commonly assessed through repeated measurement of salinity profiles from monitor wells that penetrate into underlying salt water. In Hawaii, the thickest measured freshwater lens is currently 262 m in dike-free, volcanic-rock aquifers that are overlain by thick coastal sediments. The midpoint depth (depth
Authors
Kolja Rotzoll, Delwyn S. Oki, Aly I. El-Kadi
Science and Products
Filter Total Items: 21
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
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
Authors
Scot K. Izuka, John A. Engott, Kolja Rotzoll, Maoya Bassiouni, Adam G. Johnson, Lisa D. Miller, Alan Mair
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
Authors
Adam G. Johnson, John A. Engott, Maoya Bassiouni, Kolja Rotzoll
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
Authors
John A. Engott, Adam G. Johnson, Maoya Bassiouni, Scot K. Izuka, Kolja Rotzoll
Estimating hydraulic properties from tidal attenuation in the Northern Guam Lens Aquifer, territory of Guam, USA
Tidal-signal attenuations are analyzed to compute hydraulic diffusivities and estimate regional hydraulic conductivities of the Northern Guam Lens Aquifer, Territory of Guam (Pacific Ocean), USA. The results indicate a significant tidal-damping effect at the coastal boundary. Hydraulic diffusivities computed using a simple analytical solution for well responses to tidal forcings near the periphery
Authors
Kolja Rotzoll, Stephen B. Gingerich, John W. Jenson, Aly I. El-Kadi
Numerical simulation of flow in deep open boreholes in a coastal freshwater lens, Pearl Harbor Aquifer, O‘ahu, Hawai‘i
The Pearl Harbor aquifer in southern O‘ahu is one of the most important sources of freshwater in Hawai‘i. A thick freshwater lens overlays brackish and saltwater in this coastal aquifer. Salinity profiles collected from uncased deep monitor wells (DMWs) commonly are used to monitor freshwater-lens thickness. However, vertical flow in DMWs can cause the measured salinity to differ from salinity in
Authors
Kolja Rotzoll
Effects of groundwater withdrawal on borehole flow and salinity measured in deep monitor wells in Hawai'i: implications for groundwater management
Water-resource managers in Hawai`i rely heavily on salinity profiles from deep monitor wells to estimate the thickness of freshwater and the depth to the midpoint of the transition zone between freshwater and saltwater in freshwater-lens systems. The deep monitor wells are typically open boreholes below the water table and extend hundreds of feet below sea level. Because of possible borehole-flow
Authors
Kolja Rotzoll
Changes of freshwater-lens thickness in basaltic island aquifers overlain by thick coastal sediments
Freshwater-lens thickness and long-term changes in freshwater volume in coastal aquifers are commonly assessed through repeated measurement of salinity profiles from monitor wells that penetrate into underlying salt water. In Hawaii, the thickest measured freshwater lens is currently 262 m in dike-free, volcanic-rock aquifers that are overlain by thick coastal sediments. The midpoint depth (depth
Authors
Kolja Rotzoll, Delwyn S. Oki, Aly I. El-Kadi