The FINAL report for this joint U.S. Geological Survey, University of Hawaii, University of Guam, University of Texas, and East-West Center study has been released to the public. The completion of this report involved a lot of effort and collaboration between team members from a variety of disciplines, over a period of several years. Publications and findings from this research can be found in the resources section below. For an executive summary of the findings for a natural resources manager or decision maker, please see our freshwater resources and climate change handouts (below).
Guam receives 94 to 116 inches of rain a year, two-thirds of which has historically fallen during the rainy season. An average of three tropical storms and one typhoon pass within 80 nautical miles of Guam each year, generally during the rainy season. Both flooding and drought can impact freshwater supply management and the associated infrastructure. Department of Defense (DoD) installations on Guam share freshwater resources with non-military populations, which will be impacted by changes in demographics, demand, and climate.
Projected changes in annual average (a) temperature (°F) and (b) rainfall (% change) in 2080–2099 using warming scenario RCP8.5 (“business-asusual”), as compared to the 1990–2009 baseline.
The goal of this joint U.S. Geological Survey, University of Hawaii, University of Guam, University of Texas, and East-West Center study was to: (1) provide basic understanding and specific information about water resources for U.S. Department of Defense installations on Guam, and, (2) assess the resulting impact of sea-level rise and a changing climate on freshwater availability, based on historic information, sea-level rise predictions, and global climate model temperature and precipitation output. Downscaled regional climate models, informed by a multi-model ensemble of global climate models provided projections of future climate conditions for Guam. These projected climate conditions provided input to surface-water and groundwater models developed for Guam’s hydrology.
Guam’s water resources in a future climate condition (2080–2099) are projected to diminish relative to the current climate condition. Future average temperature increases and average rainfall decreases will lead to reduced streamflow in southern Guam and reduced groundwater recharge to the NGLA. In the projected future climate, average temperatures in southern Guam will increase about 3.2°C (5.8°F), overall rainfall will decrease about 7%, and, streamflow will consequently decrease 18% in the 12 modeled regions. Similarly, across the NGLA, future groundwater recharge will be 19% less than current estimated recharge. Reduced future streamflow will decrease water availability from the Fena Valley Reservoir; however, the reservoir is expected to be able to supply water at current demand rates without lowering the reservoir level to the elevation of the water-supply intakes throughout the simulated period with a future climate. A twelve-year simulation indicates that the reservoir can supply about twice the current demand without lowering the reservoir level to the intakes.
FINAL REPORT
Gingerich, S.B., Johnson, A.G., Rosa, S.N., Marineau, M.D., Wright, S.A., Hay, L.E., Widlansky, M.J., Jenson, J.W., Wong, C.I., Banner, J.L., Keener, V.W., and Finucane, M.L., 2019, Water resources on Guam—Potential impacts of and adaptive response to climate change: U.S. Geological Survey Scientific Investigations Report 2019–5095, 55 p., https://doi.org/10.3133/sir20195095
Climate Trends and Projections for Guam – EWC and USGS Flier
Marineau, M.D., and Wright, S.A., 2015, Storage capacity of the Fena Valley Reservoir, Guam, Mariana Islands, 2014: U.S. Geological Survey Scientific Investigations Report 2015-5128, 31 p., http://dx.doi.org/10.3133/sir20155128.
Rosa, S.N., and Hay, L.E., 2017, Fena Valley Reservoir watershed and water-balance model updates and expansion of watershed modeling to southern Guam: U.S. Geological Survey Scientific Investigations Report 2017–5093, 64 p., https://doi.org/10.3133/sir20175093.
PAPERS
Beal, L.K., Wong, C.I., Bautista, K.K., Jenson, J.W., Banner, J.L., Lander, M.A., Gingerich, S.B., Partin, J.W., Hardt, B., and van Oort, N.H., 2019, Isotopic and geochemical assessment of the sensitivity of groundwater resources of Guam, Mariana Islands, to intra- and inter-annual variations in hydroclimate: Journal of Hydrology, v. 568, p. 174–183, accessed at https://doi.org/10.1016/j.jhydrol.2018.10.049.
Marineau M.D., and Wright S.A., 2017, Daily reservoir sedimentation model: Case study from the Fena Valley Reservoir, Guam: Journal of Hydraulic Engineering, v. 143, no. 9, accessed at https://doi.org/10.1061/(ASCE)HY.1943-7900.0001344.
Widlansky, M.J, Annamalai, H., Gingerich S.B., Storlazzi C.D., Marra, J.J., Hodges, K.J., Choy, B., and Kitoh, A., 2018, Tropical cyclone projections: Changing climate threats for Pacific Island defense installations: Weather, Climate and Society, DOI: https://doi.org/10.1175/WCAS-D-17-0112.1
Chunxi Zhang and Yuqing Wang, 2017, Projected Future Changes of Tropical Cyclone Activity over the western North and South Pacific in a 20-km-Mesh Regional Climate Model: Journal of Climate, DOI: http://dx.doi.org/10.1175/JCLI-D-16-0597.1
THESES
Bautista, K.K., 2017, Vadose hydrology at Jinapsan Cave, Northern Guam: University of Guam Master’s Thesis, Mangilao, Guam, 169 p. plus appendices.
Shalilian, I., 2017, Hydrogeology of the Finegayan Basin, Northern Guam Lens Aquifer: University of Guam Master’s Thesis, Mangilao, Guam, 92 p. plus appendices.
CONFERENCE ABSTRACTS
Gingerich, S.B., 2015, Water Resources on Guam: Potential Impacts and Adaptive Response to Climate Change for Department of Defense Installations, 2015 Island Sustainability Conference, University of Guam, April 15-16, 2015, Tumon, Guam.
Keener, V.W., 2015, Communicating Uncertain Impacts of Future Climate on Water Resources to Diverse Decision Makers, 2015 Island Sustainability Conference, University of Guam, April 15-16, 2015, Tumon, Guam.
Rosa, S.N., 2015, Southern Guam Watershed Model: Current and Potential Applications, The Second Conference on Water Resource Sustainability Issues on Tropical Islands, December 1-3, 2015, Honolulu, Hawaii.
Widlansky, M.J., 2015, Typhoons in future climate change, 2015 Island Sustainability Conference, University of Guam, April 15-16, 2015, Tumon, Guam.
Finucane, M.L., and Keener, V.W., 2016, Understanding Use of Information about Climate and Water Resources in Guam, 2016 Island Sustainability Conference, University of Guam, April 13, 2016, Tumon, Guam.
Keener, V.W., 2016, Guam Future Climate Downscaling Results, 2016 Island Sustainability Conference, University of Guam, April 13, 2016, Tumon, Guam.
DATA RELEASES
Fena Valley Reservoir sediment data: U.S. Geological Survey, 2017, USGS Water Data: U.S. Geological Survey National Water Information System Web page, accessed November 28, 2017, at http://dx.doi.org/10.5066/F7P55KJN.
Gingerich, S.B., 2019, SUTRA model used to evaluate the freshwater flow system for a future (2080-2099) climate on Guam, U.S. Geological Survey Data Release, https://doi.org/10.5066/P9U34ACT.
Johnson, A.G., 2019, Mean annual water-budget components for Guam for historic (1990–2009) and future (2080–2099) climate conditions, Data Release. U.S. Geological Survey Data Release accessed at https://doi.org/10.5066/P9A64801.
Rosa S.N., 2019, Southern Guam watershed model and Fena Valley Reservoir water-balance model input files for historic (1990‒2009) and future (2080‒2099) climate conditions: U.S. Geological Survey Data Release, accessed at https://doi.org/10.5066/P90S1CSX
Rosa, S.N. and Hay, L.E., 2017b, Supporting data for Fena Valley Reservoir watershed and water-balance model, southern Guam: U.S. Geological Survey data release, accessed at https://doi.org/10.5066/F7HH6HV4.
Resilient and sustainable Pacific Island communities using climate information to manage risks and support practical decision-making about climate variability and change.
Guam SERDP Project Resources
Water Resources on Guam: Potential Impacts and Adaptive Response to Climate Change for Department of Defense Installations
The FINAL report for this joint U.S. Geological Survey, University of Hawaii, University of Guam, University of Texas, and East-West Center study has been released to the public. The completion of this report involved a lot of effort and collaboration between team members from a variety of disciplines, over a period of several years. Publications and findings from this research can be found in the resources section below. For an executive summary of the findings for a natural resources manager or decision maker, please see our freshwater resources and climate change handouts (below).
Guam receives 94 to 116 inches of rain a year, two-thirds of which has historically fallen during the rainy season. An average of three tropical storms and one typhoon pass within 80 nautical miles of Guam each year, generally during the rainy season. Both flooding and drought can impact freshwater supply management and the associated infrastructure. Department of Defense (DoD) installations on Guam share freshwater resources with non-military populations, which will be impacted by changes in demographics, demand, and climate.
(% change) in 2080–2099 using warming scenario RCP8.5 (“business-asusual”),
as compared to the 1990–2009 baseline.
The goal of this joint U.S. Geological Survey, University of Hawaii, University of Guam, University of Texas, and East-West Center study was to: (1) provide basic understanding and specific information about water resources for U.S. Department of Defense installations on Guam, and, (2) assess the resulting impact of sea-level rise and a changing climate on freshwater availability, based on historic information, sea-level rise predictions, and global climate model temperature and precipitation output. Downscaled regional climate models, informed by a multi-model ensemble of global climate models provided projections of future climate conditions for Guam. These projected climate conditions provided input to surface-water and groundwater models developed for Guam’s hydrology.
Guam’s water resources in a future climate condition (2080–2099) are projected to diminish relative to the current climate condition. Future average temperature increases and average rainfall decreases will lead to reduced streamflow in southern Guam and reduced groundwater recharge to the NGLA. In the projected future climate, average temperatures in southern Guam will increase about 3.2°C (5.8°F), overall rainfall will decrease about 7%, and, streamflow will consequently decrease 18% in the 12 modeled regions. Similarly, across the NGLA, future groundwater recharge will be 19% less than current estimated recharge. Reduced future streamflow will decrease water availability from the Fena Valley Reservoir; however, the reservoir is expected to be able to supply water at current demand rates without lowering the reservoir level to the elevation of the water-supply intakes throughout the simulated period with a future climate. A twelve-year simulation indicates that the reservoir can supply about twice the current demand without lowering the reservoir level to the intakes.
FINAL REPORT
Gingerich, S.B., Johnson, A.G., Rosa, S.N., Marineau, M.D., Wright, S.A., Hay, L.E., Widlansky, M.J., Jenson, J.W., Wong, C.I., Banner, J.L., Keener, V.W., and Finucane, M.L., 2019, Water resources on Guam—Potential impacts of and adaptive response to climate change: U.S. Geological Survey Scientific Investigations Report 2019–5095, 55 p., https://doi.org/10.3133/sir20195095
REPORTS
Gingerich, S.B., Keener, V., and Finucane, M.L., 2015, Climate trends and projections for Guam, East-West Center, Honolulu, Hawaii, 2 p. IP-064724, 4/7/15.
Gingerich, S.B., Keener, V.W., and Finucane, M.L., 2019a, Guam’s water resources, East-West Center, Honolulu, Hawaiʻi, 2 p.
Gingerich, S.B., Keener, V.W., and Finucane, M.L., 2019b, Freshwater availability in Guam with projected changes in climate, East-West Center, Honolulu, Hawaii, East-West Center, 4 p.
Marineau, M.D., and Wright, S.A., 2015, Storage capacity of the Fena Valley Reservoir, Guam, Mariana Islands, 2014: U.S. Geological Survey Scientific Investigations Report 2015-5128, 31 p., http://dx.doi.org/10.3133/sir20155128.
Rosa, S.N., and Hay, L.E., 2017, Fena Valley Reservoir watershed and water-balance model updates and expansion of watershed modeling to southern Guam: U.S. Geological Survey Scientific Investigations Report 2017–5093, 64 p., https://doi.org/10.3133/sir20175093.
PAPERS
Beal, L.K., Wong, C.I., Bautista, K.K., Jenson, J.W., Banner, J.L., Lander, M.A., Gingerich, S.B., Partin, J.W., Hardt, B., and van Oort, N.H., 2019, Isotopic and geochemical assessment of the sensitivity of groundwater resources of Guam, Mariana Islands, to intra- and inter-annual variations in hydroclimate: Journal of Hydrology, v. 568, p. 174–183, accessed at https://doi.org/10.1016/j.jhydrol.2018.10.049.
Marineau M.D., and Wright S.A., 2017, Daily reservoir sedimentation model: Case study from the Fena Valley Reservoir, Guam: Journal of Hydraulic Engineering, v. 143, no. 9, accessed at https://doi.org/10.1061/(ASCE)HY.1943-7900.0001344.
Widlansky, M.J, Annamalai, H., Gingerich S.B., Storlazzi C.D., Marra, J.J., Hodges, K.J., Choy, B., and Kitoh, A., 2018, Tropical cyclone projections: Changing climate threats for Pacific Island defense installations: Weather, Climate and Society, DOI: https://doi.org/10.1175/WCAS-D-17-0112.1
Chunxi Zhang and Yuqing Wang, 2017, Projected Future Changes of Tropical Cyclone Activity over the western North and South Pacific in a 20-km-Mesh Regional Climate Model: Journal of Climate, DOI: http://dx.doi.org/10.1175/JCLI-D-16-0597.1
THESES
Bautista, K.K., 2017, Vadose hydrology at Jinapsan Cave, Northern Guam: University of Guam Master’s Thesis, Mangilao, Guam, 169 p. plus appendices.
Shalilian, I., 2017, Hydrogeology of the Finegayan Basin, Northern Guam Lens Aquifer: University of Guam Master’s Thesis, Mangilao, Guam, 92 p. plus appendices.
CONFERENCE ABSTRACTS
Gingerich, S.B., 2015, Water Resources on Guam: Potential Impacts and Adaptive Response to Climate Change for Department of Defense Installations, 2015 Island Sustainability Conference, University of Guam, April 15-16, 2015, Tumon, Guam.
Keener, V.W., 2015, Communicating Uncertain Impacts of Future Climate on Water Resources to Diverse Decision Makers, 2015 Island Sustainability Conference, University of Guam, April 15-16, 2015, Tumon, Guam.
Rosa, S.N., 2015, Southern Guam Watershed Model: Current and Potential Applications, The Second Conference on Water Resource Sustainability Issues on Tropical Islands, December 1-3, 2015, Honolulu, Hawaii.
Widlansky, M.J., 2015, Typhoons in future climate change, 2015 Island Sustainability Conference, University of Guam, April 15-16, 2015, Tumon, Guam.
Finucane, M.L., and Keener, V.W., 2016, Understanding Use of Information about Climate and Water Resources in Guam, 2016 Island Sustainability Conference, University of Guam, April 13, 2016, Tumon, Guam.
Keener, V.W., 2016, Guam Future Climate Downscaling Results, 2016 Island Sustainability Conference, University of Guam, April 13, 2016, Tumon, Guam.
DATA RELEASES
Fena Valley Reservoir sediment data: U.S. Geological Survey, 2017, USGS Water Data: U.S. Geological Survey National Water Information System Web page, accessed November 28, 2017, at http://dx.doi.org/10.5066/F7P55KJN.
Gingerich, S.B., 2019, SUTRA model used to evaluate the freshwater flow system for a future (2080-2099) climate on Guam, U.S. Geological Survey Data Release, https://doi.org/10.5066/P9U34ACT.
Johnson, A.G., 2019, Mean annual water-budget components for Guam for historic (1990–2009) and future (2080–2099) climate conditions, Data Release. U.S. Geological Survey Data Release accessed at https://doi.org/10.5066/P9A64801.
Rosa S.N., 2019, Southern Guam watershed model and Fena Valley Reservoir water-balance model input files for historic (1990‒2009) and future (2080‒2099) climate conditions: U.S. Geological Survey Data Release, accessed at https://doi.org/10.5066/P90S1CSX
Rosa, S.N. and Hay, L.E., 2017b, Supporting data for Fena Valley Reservoir watershed and water-balance model, southern Guam: U.S. Geological Survey data release, accessed at https://doi.org/10.5066/F7HH6HV4.
Zhang, 2016, Dynamical Downscaled and Projected Climate for the Pacific Islands/Guam: https://cida.usgs.gov/thredds/catalog.html?dataset=cida.usgs.gov/guam
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Resilient and sustainable Pacific Island communities using climate information to manage risks and support practical decision-making about climate variability and change.
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