Changes in groundwater recharge under projected climate in the upper Colorado River basin

Tillman, Fred D.; Gangopadhyay, Subhrendu; Pruitt, T.

doi:10.1002/2016gl069714

Cited by 33 publications

(26 citation statements)

References 35 publications

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“…Given that more efficient processing of carbon generally occurs under oxic conditions, the development of suboxic conditions in riverbed sediments are likely to have a significant impact on the extent of carbon utilization. Understanding such linkages is increasingly important given modeling predictions for the next 50 years in the UCRB, where warming temperatures and decreasing snowpack in the upper Colorado River basin will likely contribute to earlier snowmelt [ Adam et al , ; Painter et al , ] and decreases in Colorado River discharge [ Ficklin et al , ] with base flow occurring for longer periods of the year [ Christensen and Lettenmaier , ; Tillman et al , ]. The loss of strong seasonal behavior and longer base flow periods will likely drive greater persistence of groundwater‐dominated riverbed sediments.…”

Section: Discussionmentioning

confidence: 99%

Seasonal hyporheic dynamics control coupled microbiology and geochemistry in Colorado River sediments

et al. 2016

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Riverbed microbial communities play an oversized role in many watershed ecosystem functions, including the processing of organic carbon, cycling of nitrogen, and alterations to metal mobility. The structure and activity of microbial assemblages depend in part on geochemical conditions set by river‐groundwater exchange or hyporheic exchange. To assess how seasonal changes in river‐groundwater mixing affect these populations in a snowmelt‐dominated fluvial system, vertical sediment and pore water profiles were sampled at three time points at one location in the hyporheic zone of the Colorado River and analyzed by using geochemical measurements, 16S rRNA gene sequencing, and ecological modeling. Oxic river water penetrated deepest into the subsurface during peak river discharge, while under base flow conditions, anoxic groundwater dominated shallower depths. Over a 70 cm thick interval, riverbed sediments were therefore exposed to seasonally fluctuating redox conditions and hosted microbial populations statistically different from those at both shallower and deeper locations. Additionally, microbial populations within this zone were shown to be the most dynamic across sampling time points, underlining the critical role that hyporheic mixing plays in constraining microbial abundances. Given such mixing effects, we anticipate that future changes in river discharge in mountainous, semiarid western U.S. watersheds may affect microbial community structure and function in riverbed environments, with potential implications for biogeochemical processes in riparian regions.

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Section: Discussionmentioning

confidence: 99%

Seasonal hyporheic dynamics control coupled microbiology and geochemistry in Colorado River sediments

et al. 2016

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“…Stable to slight increases in UCRB‐wide groundwater recharge are projected through 2099 (Tillman et al ), but climate impacts on simulated recharge vary within the basin. Subregions at northernmost latitudes within the UCRB are projected to experience mainly increased recharge while southernmost basins are expected to see mainly decreased recharge.…”

Section: Discussionmentioning

confidence: 99%

“…These daily temperature and precipitation data for the UCRB study area were obtained from the downscaled climate and hydrology projections archive (http://gdo-dcp.ucllnl.org/downscaled_cmip_projections/dcpInterface.html; Bureau of Reclamation ). Owing to similarities in projected changes in UCRB recharge from separate and combined RCP simulations reported by Tillman et al (), recharge simulation results from all 97 ensemble members are grouped together for this study and not separated by emission scenario.…”

Section: Methods and Datamentioning

confidence: 99%

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Changes in Projected Spatial and Seasonal Groundwater Recharge in the Upper Colorado River Basin

Tillman¹,

Gangopadhyay

Pruitt

2017

Groundwater

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The Colorado River is an important source of water in the western United States, supplying the needs of more than 38 million people in the United States and Mexico. Groundwater discharge to streams has been shown to be a critical component of streamflow in the Upper Colorado River Basin (UCRB), particularly during low-flow periods. Understanding impacts on groundwater in the basin from projected climate change will assist water managers in the region in planning for potential changes in the river and groundwater system. A previous study on changes in basin-wide groundwater recharge in the UCRB under projected climate change found substantial increases in temperature, moderate increases in precipitation, and mostly periods of stable or slight increases in simulated groundwater recharge through 2099. This study quantifies projected spatial and seasonal changes in groundwater recharge within the UCRB from recent historical (1950 to 2015) through future (2016 to 2099) time periods, using a distributed-parameter groundwater recharge model with downscaled climate data from 97 Coupled Model Intercomparison Project Phase 5 (CMIP5) climate projections. Simulation results indicate that projected increases in basin-wide recharge of up to 15% are not distributed uniformly within the basin or throughout the year. Northernmost subregions within the UCRB are projected an increase in groundwater recharge, while recharge in other mainly southern subregions will decline. Seasonal changes in recharge also are projected within the UCRB, with decreases of 50% or more in summer months and increases of 50% or more in winter months for all subregions, and increases of 10% or more in spring months for many subregions.

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“…Groundwater recharge can be evaluated by using water budget with seepage meters [42,43], tracers [44,45], modelling [46,47], and groundwater level change [48]. To analyze the water budget and estimate the groundwater recharge in the MRB area, we used the soil-water balance (SWB) model, which has been applied in various studies to understand the impact of future climate change and anthropogenic effects on groundwater resources [49][50][51]. The SWB model integrates GIS-gridded datasets (land-use classification, soil properties, flow direction, and available soil-water capacity) with observed climate data (precipitation, air temperature, and evaporation).…”

Section: Spatial Variation Of Groundwatermentioning

confidence: 99%

Natural and Human-Induced Drivers of Groundwater Sustainability: A Case Study of the Mangyeong River Basin in Korea

2019

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The sustainability of rural areas depends on the availability of water resources. The Mangyeong River Basin (MRB) in Korea faces a water supply shortage for agriculture and industry. Based on 11-year (2005–2015) precipitation and groundwater monitoring data, groundwater sustainability was evaluated in terms of natural and man-made factors and their spatio-temporal variations. A precipitation time-series revealed a declining trend, but there were different seasonal trends between wet and dry periods, with declining and rising trends, respectively. Groundwater hydrographs from five national groundwater monitoring wells showed temporal variations. Groundwater wells located in downstream areas showed both recharge from upgradient areas and local man-made impacts (e.g. from pumping), resulting in an ambiguous relationship between precipitation and water levels. However, other monitoring wells in the upstream areas displayed water level responses to precipitation events, with a declining trend. Using the standardized precipitation index at a time scale of 12 months (SPI-12) and the standardized groundwater level anomaly, meteorological and groundwater drought conditions were compared to infer the relationship between precipitation deficit and groundwater shortage in the aquifer. The SPI results indicated severely dry to extremely dry conditions during 2008–2009 and 2015. However, the standardized groundwater level anomaly showed various drought conditions for groundwater, which were dependent on the site-specific hydrogeological characteristics. Finally, groundwater sustainability was assessed using water budget modelling and water quality data. Presently, if groundwater is used above 39.2% of the recharge value in the MRB, groundwater drought conditions occur throughout the basin. Considering water quality issues, with nitrate being elevated above the natural background, this critical abstraction value becomes 28.4%. Consequently, in the MRB, sustainable groundwater management should embrace both natural and human-induced factors to regulate over-exploitation and prevent contamination.

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Changes in groundwater recharge under projected climate in the upper Colorado River basin

Cited by 33 publications

References 35 publications

Seasonal hyporheic dynamics control coupled microbiology and geochemistry in Colorado River sediments

Seasonal hyporheic dynamics control coupled microbiology and geochemistry in Colorado River sediments

Changes in Projected Spatial and Seasonal Groundwater Recharge in the Upper Colorado River Basin

Natural and Human-Induced Drivers of Groundwater Sustainability: A Case Study of the Mangyeong River Basin in Korea

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