scholarly journals Development of streamflow projections under changing climate conditions over Colorado River Basin headwaters

2010 ◽  
Vol 7 (4) ◽  
pp. 5577-5619 ◽  
Author(s):  
W. P. Miller ◽  
T. C. Piechota ◽  
S. Gangopadhyay ◽  
T. Pruitt
Keyword(s):  
River Basin ◽  
Colorado River ◽  
Hydrologic Model ◽  
Colorado River Basin ◽  
San Juan ◽  
Climate Conditions ◽  
Average Decrease ◽  
Changing Climate ◽  
San Juan River ◽  
The Impact

Abstract. The current drought over the Colorado River Basin has raised concerns that the US Department of the Interior, Bureau of Reclamation (Reclamation) may impose water shortages over the lower portion of the basin for the first time in history. The guidelines that determine levels of shortage are affected by forecasts determined by the Colorado Basin River Forecast Center (CBRFC). While these forecasts by the CBRFC are useful, water managers within the basin are interested in long-term projections of streamflow, particularly under changing climate conditions. In this study, a bias-corrected, statistically downscaled dataset of projected climate is used to force a hydrologic model utilized by the CBRFC to derive projections of streamflow over the Green, Gunnison, and San Juan River headwater basins located within the Colorado River Basin. This study evaluates the impact of changing climate to evapotranspiration rates. The impact to evapotranspiration rates is taken into consideration and incorporated into the development of streamflow projections over Colorado River headwater basins in this study. Additionally, the CBRFC hydrologic model is modified to account for impacts to evapotranspiration due to changing temperature over the basin. Adjusting evapotranspiration demands over the Gunnison resulted in a 6% to 13% average decrease in runoff over the Gunnison River Basin when compared to static evapotranspiration rates. Streamflow projections derived using projections of future climate and the CBRFC's hydrologic model resulted in decreased runoff in 2 of the 3 basins considered. Over the Gunnison and San Juan River basins, a 10% to 15% average decrease in basin runoff is projected through the year 2099. However, over the Green River basin, a 5% to 8% increase in basin runoff is projected through 2099. Evidence of nonstationary behavior is apparent over the Gunnison and San Juan River basins.

scholarly journals Development of streamflow projections under changing climate conditions over Colorado River basin headwaters

2011 ◽  
Vol 15 (7) ◽  
pp. 2145-2164 ◽  
Author(s):  
W. P. Miller ◽  
T. C. Piechota ◽  
S. Gangopadhyay ◽  
T. Pruitt
Keyword(s):  
River Basin ◽  
Colorado River ◽  
Colorado River Basin ◽  
San Juan ◽  
Climate Conditions ◽  
Average Decrease ◽  
Changing Climate ◽  
San Juan River ◽  
Headwater Basins ◽  
The Impact

Abstract. The current drought over the Colorado River Basin has raised concerns that the US Department of the Interior, Bureau of Reclamation (Reclamation) may impose water shortages over the lower portion of the basin for the first time in history. The guidelines that determine levels of shortage are affected by relatively short-term (3 to 7 month) forecasts determined by the Colorado Basin River Forecast Center (CBRFC) using the National Weather Service (NWS) River Forecasting System (RFS) hydrologic model. While these forecasts by the CBRFC are useful, water managers within the basin are interested in long-term projections of streamflow, particularly under changing climate conditions. In this study, a bias-corrected, statistically downscaled dataset of projected climate is used to force the NWS RFS utilized by the CBRFC to derive projections of streamflow over the Green, Gunnison, and San Juan River headwater basins located within the Colorado River Basin. This study evaluates the impact of changing climate to evapotranspiration rates and contributes to a better understanding of how hydrologic processes change under varying climate conditions. The impact to evapotranspiration rates is taken into consideration and incorporated into the development of streamflow projections over Colorado River headwater basins in this study. Additionally, the NWS RFS is modified to account for impacts to evapotranspiration due to changing temperature over the basin. Adjusting evapotranspiration demands resulted in a 6 % to 13 % average decrease in runoff over the Gunnison River Basin when compared to static evapotranspiration rates. Streamflow projections derived using projections of future climate and the NWS RFS provided by the CBRFC resulted in decreased runoff in 2 of the 3 basins considered. Over the Gunnison and San Juan River basins, a 10 % to 15 % average decrease in basin runoff is projected through the year 2099. However, over the Green River basin, a 5 % to 8 % increase in basin runoff is projected through 2099. Evidence of nonstationary behavior is apparent over the Gunnison and San Juan River basins.

scholarly journals Climate-driven disturbances in the San Juan River sub-basin of the Colorado River

2018 ◽  
Vol 22 (1) ◽  
pp. 709-725 ◽  
Author(s):  
Katrina E. Bennett ◽  
Theodore J. Bohn ◽  
Kurt Solander ◽  
Nathan G. McDowell ◽  
Chonggang Xu ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Land Cover ◽  
River Basin ◽  
Colorado River ◽  
Hydrologic Model ◽  
San Juan ◽  
Forest Disturbances ◽  
San Juan River ◽  
The Impact

Abstract. Accelerated climate change and associated forest disturbances in the southwestern USA are anticipated to have substantial impacts on regional water resources. Few studies have quantified the impact of both climate change and land cover disturbances on water balances on the basin scale, and none on the regional scale. In this work, we evaluate the impacts of forest disturbances and climate change on a headwater basin to the Colorado River, the San Juan River watershed, using a robustly calibrated (Nash–Sutcliffe efficiency 0.76) hydrologic model run with updated formulations that improve estimates of evapotranspiration for semi-arid regions. Our results show that future disturbances will have a substantial impact on streamflow with implications for water resource management. Our findings are in contradiction with conventional thinking that forest disturbances reduce evapotranspiration and increase streamflow. In this study, annual average regional streamflow under the coupled climate–disturbance scenarios is at least 6–11 % lower than those scenarios accounting for climate change alone; for forested zones of the San Juan River basin, streamflow is 15–21 % lower. The monthly signals of altered streamflow point to an emergent streamflow pattern related to changes in forests of the disturbed systems. Exacerbated reductions of mean and low flows under disturbance scenarios indicate a high risk of low water availability for forested headwater systems of the Colorado River basin. These findings also indicate that explicit representation of land cover disturbances is required in modeling efforts that consider the impact of climate change on water resources.

scholarly journals Climate change and climate-driven disturbances in the San Juan River sub-basin of the Colorado River

2017 ◽  
Author(s):  
Katrina E. Bennett ◽  
Theodore Bohn ◽  
Kurt Solander ◽  
Nathan G. McDowell ◽  
Chonggang Xu ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Land Cover ◽  
River Basin ◽  
Colorado River ◽  
Hydrologic Model ◽  
San Juan ◽  
Forest Disturbances ◽  
San Juan River ◽  
The Impact

Abstract. Accelerated climate change and associated forest disturbances in the Southwestern USA are anticipated to have substantial impacts on regional water resources. Few studies have quantified the impact of both climate change and land cover disturbances on water balances at the basin scale, and none at the regional scale. In this work, we evaluate the impacts of forest disturbances and climate change for a headwater basin to the Colorado River, the San Juan River watershed, using a robustly-calibrated (Nash Sutcliff 0.80) hydrologic model run with updated formulations that improve estimates of evapotranspiration for semi-arid regions. Our results show that future disturbances will have a substantial impact on streamflow with implications for water resource management. Our findings are in contradiction with conventional thinking that forest disturbances reduce ET and increase streamflow. In this study, annual average regional streamflow under the coupled climate-disturbances scenarios is at least 6–11 % lower than those scenarios accounting for climate change alone, and for forested zones of the San Juan River basin streamflow is 15–21 % lower. The monthly signals of altered streamflow point to an emergent streamflow pattern related to changes in forests of the disturbed systems. Exacerbated reductions of mean and low flows under disturbance scenarios indicate a high risk of lower water availability for forested headwater systems to the Colorado River basin. These findings also indicate that explicit representation of land cover disturbances is required in modelling efforts that consider the impact of climate change on water resources.

scholarly journals Sensitivity Studies on the Impact of Dust and Aerosol Pollution Acting as Cloud Nucleating Aerosol on Orographic Precipitation in the Colorado River Basin

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Vandana Jha ◽  
William R. Cotton ◽  
Gustavo G. Carrió ◽  
Robert Walko
Keyword(s):  
River Basin ◽  
Colorado River ◽  
Cloud Condensation Nuclei ◽  
Winter Season ◽  
Colorado River Basin ◽  
Orographic Precipitation ◽  
Condensation Nuclei ◽  
Aerosol Pollution ◽  
Sensitivity Studies ◽  
The Impact

In this study, we examine the cumulative effect of pollution aerosol and dust acting as cloud nucleating aerosol;cloud condensation nuclei (CCN), giant cloud condensation nuclei, and ice nuclei (IN), on orographic precipitation in the Rocky Mountains. We analyze the results of sensitivity studies for specific cases in 2004-2005 winter season to analyze the relative impact of aerosol pollution and dust acting as CCN and IN on precipitation in the Colorado River Basin. Dust is varied from 3 to 10 times in the experiments, and the response is found to be nonmonotonic and depends on various environmental factors. The sensitivity studies show that adding dust in a wet system increases precipitation when IN effects are dominant. For a relatively dry system high concentrations of dust can result in overseeding the clouds and reductions in precipitation. However, when adding dust to a system with warmer cloud bases where drizzle formation is active, the response is nonmonotonic.

scholarly journals The implications of climate change scenario selection for future streamflow projection in the Upper Colorado River Basin

2012 ◽  
Vol 16 (11) ◽  
pp. 3989-4007 ◽  
Author(s):  
B. L. Harding ◽  
A. W. Wood ◽  
J. R. Prairie
Keyword(s):  
River Basin ◽  
Media Coverage ◽  
Colorado River ◽  
Global Climate Models ◽  
Colorado River Basin ◽  
Change Scenario ◽  
Climate Projections ◽  
Model Ensemble ◽  
Upper Colorado River Basin ◽  
The Impact

Abstract. The impact of projected 21st century climate conditions on streamflow in the Upper Colorado River Basin was estimated using a multi-model ensemble approach wherein the downscaled outputs of 112 future climate projections from 16 global climate models (GCMs) were used to drive a macroscale hydrology model. By the middle of the century, the impacts on streamflow range, over the entire ensemble, from a decrease of approximately 30% to an increase of approximately the same magnitude. Although prior studies and associated media coverage have focused heavily on the likelihood of a drier future for the Colorado River Basin, approximately 25 to 35% of the ensemble of runs, by 2099 and 2039, respectively, result in no change or increases in streamflow. The broad range of projected impacts is primarily the result of uncertainty in projections of future precipitation, and a relatively small part of the variability of precipitation across the projections can be attributed to the effect of emissions pathways. The simulated evolution of future temperature is strongly influenced by emissions, but temperature has a smaller influence than precipitation on flow. Period change statistics (i.e., the change in flow from one 30-yr period to another) vary as much within a model ensemble as between models and emissions pathways. Even by the end of the current century, the variability across the projections is much greater than changes in the ensemble mean. The relatively large ensemble analysis described herein provides perspective on earlier studies that have used fewer scenarios, and suggests that impact analyses relying on one or a few climate scenarios are unacceptably influenced by the choice of projections.

scholarly journals Impact of Irrigation over the California Central Valley on Regional Climate

2017 ◽  
Vol 18 (5) ◽  
pp. 1341-1357 ◽  
Author(s):  
Zhao Yang ◽  
Francina Dominguez ◽  
Xubin Zeng ◽  
Huancui Hu ◽  
Hoshin Gupta ◽  
...  
Keyword(s):  
Water Vapor ◽  
River Basin ◽  
Sierra Nevada ◽  
Colorado River ◽  
Regional Climate ◽  
Central Valley ◽  
Colorado River Basin ◽  
Windward Side ◽  
Irrigation Scheme ◽  
The Impact

Abstract Irrigation, while being an important anthropogenic factor affecting the local to regional water cycle, is not typically represented in regional climate models. An irrigation scheme is incorporated into the Noah land surface scheme of the Weather Research and Forecasting (WRF) Model that has a calibrated convective parameterization and a tracer package is used to tag and track water vapor. To assess the impact of irrigation over the California Central Valley (CCV) on the regional climate of the U.S. Southwest, simulations are run (for three dry and three wet years) both with and without the irrigation scheme. Incorporation of the irrigation scheme resulted in simulated surface air temperature and humidity that were closer to observations, decreased depth of the planetary boundary layer over the CCV, and increased convective available potential energy. The result was an overall increase in precipitation over the Sierra Nevada range and the Colorado River basin during the summer. Water vapor rising from the irrigated region mainly moved northeastward and contributed to precipitation in Nevada and Idaho. Specifically, the results indicate increased precipitation on the windward side of the Sierra Nevada and over the Colorado River basin. The former is possibly linked to a sea-breeze-type circulation near the CCV, while the latter is likely associated with a wave pattern related to latent heat release over the moisture transport belt.

scholarly journals Spatial and Temporal Analysis of Precipitation and Effective Rainfall Using Gauge Observations, Satellite, and Gridded Climate Data for Agricultural Water Management in the Upper Colorado River Basin

2018 ◽  
Vol 10 (12) ◽  
pp. 2058 ◽  
Author(s):  
Mahyar Aboutalebi ◽  
Alfonso Torres-Rua ◽  
Niel Allen
Keyword(s):  
River Basin ◽  
Wind Direction ◽  
Colorado River ◽  
Colorado River Basin ◽  
Effective Rainfall ◽  
Coverage Area ◽  
Farm Level ◽  
Upper Colorado River Basin ◽  
Gauge Station ◽  
The Impact

Accurate spatial and temporal precipitation estimates are important for hydrological studies of irrigation depletion, net irrigation requirement, natural recharge, and hydrological water balances in defined areas. This analysis supports the verification of water savings (reduced depletion) from deficit irrigation of pastures in the Upper Colorado River Basin. The study area has diverse topography with scattered fields and few precipitation gauges that are not representative of the basin. Gridded precipitation products from TRMM-3B42, PRISM, Daymet, and gauge observations were evaluated on two case studies located in Colorado and Wyoming during the 2014–2016 irrigation seasons. First, the resolution at the farm level is discussed. Next, bias occurrence at different time scales (daily to monthly) is evaluated and addressed. Then, the coverage area of the gauge station, along with the impact of the dominant wind direction on the shape of the coverage area, is evaluated. Ultimately, available actual ET maps derived from the METRIC model are used to estimate spatial effective rainfall. The results show that the spatial resolutions of TRMM and PRISM are not adequate at the farm level, while Daymet is a better fit but lacks the adequate latency versus TRMM and PRISM. When compared against local weather station records, all three spatial datasets were found to have a bias that decreases at coarser temporal intervals. However, the performance of Daymet and PRISM at the monthly time step is acceptable, and they can be used for water resource management at the farm level. The adequacy of an existing gauge station for a given farm location depends on the willingness to accept the risk of the bias associated with a non-persistent, non-symmetric gauge coverage area that is highly correlated with the dominant wind direction. Among all goodness of fit statistics considered in the study, the interpretation of the summation of error makes more sense for quantifying the rainfall bias and risk for the user. Finally, based on the USDA-SCS model and actual spatial ET, overall, seasonal effective rainfall tends to be less than 60% of total rainfall for agricultural lands.

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