Maintaining water quality in large reservoirs is crucial to ensure continued delivery of high-quality water to consumers for municipal and agricultural needs. Lake Mead, a large reservoir in the desert southwest, USA, is projected to be affected by both loss of volume and rising air temperatures through the end of the 21st century. In this study, reductions in lake volume, coupled with downscaled climate projections for rising air temperatures through the end of the 21st century, are incorporated into the 3D hydrodynamic and water quality model for Lake Mead. If current management practices continue in the future, simulations indicate water temperatures will increase in all scenarios and could increase by as much 2℃ under the most pessimistic scenarios, but nutrient loads would not increase to concerning levels. Releases from the dam to downstream users are projected to be much warmer, and warmer water temperatures and significant dissolved oxygen in the water column are expected to cause challenges for ecosystem and recreation in the future. Surprisingly, during the Winter and Autumn, retention of heat in Lake Mead is more pronounced at higher surface elevations than the lower elevations as expected. The effects of these projections on the lake water quality and consequently, lake management decisions, are discussed.
References
[1]
Allan, M., Hamilton, D., & Muraoka, K. (2017). A Coupled Hydrodynamic-Ecological Model to Test Management Options for Restoration of Lakes Onoke and Wairarapa. University of Waikato.
[2]
Amadori, M., Giovannini, L., Toffolon, M., Piccolroaz, S., Zardi, D., Brescani, M. et al. (2021). Multi-Scale Evaluation of a 3D Lake Model Forced by an Atmospheric Model. Environmental Modelling and Software, 139, Article ID: 105017. https://doi.org/10.1016/j.envsoft.2021.105017
[3]
Butcher, J., Nover, D., Johnson, T., & Clark, C. (2015). Sensitivity of Lake Thermal and Mixing Dynamics to Climate Change. Climate Change, 129, 295-305. https://doi.org/10.1007/s10584-015-1326-1
[4]
Casamitjana, X., Serra, T., Colomer, J., Beserba, C., & Perez-Losada, J. (2003). Effects of the Water Withdrawal in the Stratification Patterns of a Reservoir. Hydrobiologia, 504, 21-28. https://doi.org/10.1023/B:HYDR.0000008504.61773.77
[5]
Chao, S., Lyra, A., Mourao, C., Dereczynski, C., Pilotto, I., Gomes, J. et al. (2014). Assessment of Climate Change in South America under RCP 4.5 and 8.5 Downscaling Scenarios. American Journal of Climate Change, 3, 512-525. https://doi.org/10.4236/ajcc.2014.35043
[6]
Chung, S., Hipsey, M., & Imberger, J. (2009). Modelling the Propagation of Turbid Density Inflows into a Stratified Lake: Daecheong Reservoir, Korea. Environmental Modelling & Software, 24, 1467-1482. https://doi.org/10.1016/j.envsoft.2009.05.016
[7]
Chung, S., Imberger, J., Hipsey, M., & Lee, H. (2014). The Influence of Physical and Physiological Processes on the Spatial Heterogeneity of a Microcystis Bloom in a Stratified Reservoir. Ecological Modelling, 289, 133-149. https://doi.org/10.1016/j.ecolmodel.2014.07.010
[8]
Colorado River Water Users Association (2021). Bureau of Reclamation. https://www.crwua.org/bor.html
[9]
Ding, L., Hannoun, I., List, E., & Tietjen, T. (2014). Development of a Phosphorus Budget for Lake Mead. Lake and Reservoir Management, 30, 143-156. https://doi.org/10.1080/10402381.2014.899656
[10]
Gao, Q., He, G., Fang, H., Bai, S., & Huang, L. (2018). Numerical Simulation of Water Age and Its Potential Effects on the Water Quality in Xiangxi Bay of Three Gorges Reservoir. Journal of Hydrology, 566, 484-499. https://doi.org/10.1016/j.jhydrol.2018.09.033
[11]
Gibbons, J., & Chakraborti, S. (2011). Nonparametric Statistical Inference. In M. Lovric (Ed.), International Encyclopedia of Statistical Science (pp. 977-979). CRC Press. https://doi.org/10.1007/978-3-642-04898-2_420
[12]
Hannoun, D., Tietjen, T., & Brooks, K. (2021). The Potential Effects of Drawdown on a Newly Constructed Drinking Water Intake: Study Case in Las Vegas, NV. Water Utility Journal, 27, 1-13.
[13]
Hodges, B., & Dallimore, C. (2013). Estuary, Lake, and Coastal Ocean Model: ELCOM v2.2 Science Manual. University of Western Australia.
[14]
Hodges, B., & Dallimore, C. (2019). Aquatic Ecosystem Model: AEM3D v1.0 User Manual. University of Western Australia.
[15]
Horne, A., & Goldman, C. (1994). Limnology. McGraw-Hill.
[16]
Kalansky, J., Sheffield, S., Cayan, D., & Pierce, D. (2018). Climate Conditions in Clark County, NV: An Evaluation of Historic and Projected Future Climate Change Using Global Climate Models. Water Utility Climate Alliance.
[17]
Kim, H., Lee, D., Park, C., & Kil, S. (2015). Evaluating Landslide Hazards Using RCP 4.5 and 8.5 Scenarios. Environmental Earth Science, 73, 1385-1400. https://doi.org/10.1007/s12665-014-3775-7
[18]
LaBounty, J., & Burns, N. (2005). Characterization of Boulder Basin, Lake Mead, Nevada-Arizona, USA—Based on Analysis of 34 Limnological Parameters. Lake and Reservoir Management, 21, 277-307. https://doi.org/10.1080/07438140509354435
Milly, P., & Dunne, K. (2020). Colorado River Flow Dwindles as Warming-Driven Loss of Reflective Snow Energizes Evaporation. Science, 367, 1252-1255. https://doi.org/10.1126/science.aay9187
[21]
Nevada Division of Environmental Protection (2003). Evaluation of Total Maximum Daily Loads and Associated Water Quality Standards Attainment for the Las Vegas Wash, Las Vegas Bay and Lake Mead. https://ndep.nv.gov/uploads/water-tmdl-docs/las_vegas_tmdl.pdf
[22]
NOAA (2019). National Centers for Environmental Information: Daily Summaries Station Details: McCarran International Airport, NV, US. https://www.ncdc.noaa.gov/cdo-web/datasets/GHCND/stations/GHCND:USW00023169/detail
[23]
NOAA (2022, May 11). Comparative Climactic Data (CCD). https://www.ncei.noaa.gov/products/land-based-station/comparative-climatic-data
[24]
NREL (2020). Measurement and Instrumentation Data Center. https://midcdmz.nrel.gov/apps/sitehome.pl?site=UNLV
[25]
Pierce, D., Cayan, D., & Thrasher, B. (2014). Statistical Downscaling Using Localized Constructed Analogs (LOCA). Journal of Hydrometeorology, 15, 2558-2585. https://doi.org/10.1175/JHM-D-14-0082.1
[26]
Preston, A., Hannoun, I., List, E., Rackley, I., & Tietjen, T. (2014). Three-Dimensional Management Model for Lake Mead, Nevada, Part 1: Model Calibration and Validation. Lake and Reservoir Management, 30, 285-302. https://doi.org/10.1080/10402381.2014.927941
[27]
Saber, A., James, D., & Hannoun, I. (2020). Effects of Lake Water Level Fluctuation Due to Drought and Extreme Winter Precipitation on Winter Mixing and Water Quality on an Alpine Lake, Case Study: Lake Arrowhead, California. Science of the Total Environment, 714, Article ID: 136762. https://doi.org/10.1016/j.scitotenv.2020.136762
[28]
Sahoo, G., Forrest, A., Schladow, S., Reuter, J., Coats, E., & Dettinger, M. (2016). Climate Change Impacts on Lake Thermal Dynamics and Ecosystem Vulnerabilities. Limnology Oceanography, 61, 496-507. https://doi.org/10.1002/lno.10228
[29]
Saltelli, A., Tarantola, S., & Campolongo, F. (2000). Sensitivity Analysis as an Ingredient of Modeling. Statistical Science, 15, 377-395.
[30]
Southern Nevada Water Authority (2021). Lower Colorado River Database. https://exapps.lvvwd.com/WaterQuality/login.aspx?action=&uuid
[31]
Southern Nevada Water Authority (2022). Water Resource Plan.
[32]
Tennessee Valley Authority. (1972). Heat and Mass Transfer between a Water Surface and the Atmosphere. Water Resources Research Laboratory Report 14, Report No. 0-6803.
[33]
Tietjen, T. (2015). Drought and Water Quality in Lake Mead. Lakeline, 34-38.
[34]
Udall, B., & Overpeck, J. (2017). The Twenty-First Century Colorado River Hot Drought and Implications for the Future. Water Resources Research, 53, 2404-2418. https://doi.org/10.1002/2016WR019638
[35]
United States Bureau of Reclamation (2008). 2001 Lake Mead Sedimentation Survey. U.S. Department of the Interior.
[36]
United States Bureau of Reclamation (2020b, December 21). Reclamation Announces 2020 Colorado River Operating Conditions. https://www.usbr.gov/newsroom/newsroomold/newsrelease/detail.cfm?RecordID=67383
[37]
United States Bureau of Reclamation. (2020a). Lower Colorado Region: Archives of Daily Reservoir & River Conditions. https://www.usbr.gov/lc/region/g4000/levels_archive.html
[38]
USGS (2020a). National Water Information System: Diamond Creek near Peachtree Springs, AZ. https://waterdata.usgs.gov/nwis/uv?site_no=09404208
[39]
USGS (2020b). National Water Information System: Las Vegas Wash at Pabco Rd, Henderson, NV. https://waterdata.usgs.gov/nwis/uv?site_no=09419700
[40]
USGS (2020c). National Water Information System: Muddy River at Moapa, NV. https://waterdata.usgs.gov/nwis/uv?site_no=09416000
[41]
USGS (2020d). National Water Information System: Virgin River at Littlefield, AZ. https://waterdata.usgs.gov/usa/nwis/uv?09415000
[42]
Woolway, R., Kraemer, B., Lenters, J. M., O’Reilly, C., & Sharma, S. (2020). Global Lake Responses to Climate Change. Nature Reviews Earth & Environment, 1, 388-403. https://doi.org/10.1038/s43017-020-0067-5
[43]
Woolway, R., Sharma, S., Wyhenmeyer, G., Debolskiy, A., Golub, M., & Mercado-Bettin, D. (2021). Phenological Shifts in Lake Stratification under Climate Change. Nature Communications, 12, Article No. 2318. https://doi.org/10.1038/s41467-021-22657-4
[44]
Zamani, B., Koch, M., & Hodges, B. (2020). Effects of Morphology in Controlling Propagation Density Currents in a Reservoir Using Uncalibrated Three-Dimensional Hydrodynamic Modeling. Journal of Limnology, 79. https://doi.org/10.4081/jlimnol.2020.1942
