Ryan Bailey

Assistant Professor

Department of Civil and Environmental Engineering
1372 Campus Delivery
Fort Collins, CO 80523
(970) 491-​5045

Dr. Bailey’s research objectives focus on assessing groundwater quantity and groundwater quality in watershed systems under various management schemes and climate scenarios. His research group performs field work and numerical model application and development to achieve these objectives. The interaction between groundwater and surface water often is essential in these applications. His research group’s projects include:

  • Impact of groundwater pumping on streamflow and groundwater-​surface water interactions
  • Mobilization, fate, and transport of selenium and uranium in semi-​arid irrigated stream-​aquifer systems
  • Fate, transport, and management of salinity in semi-​arid irrigated groundwater systems
  • Nitrogen and phosphorus transport in a highly managed coupled groundwater-​surface water watershed system

Sustaining groundwater supply in semi-​arid aquifer systems requires assessing production systems and on-​farm technology in terms of their effect on the regional groundwater system. Through the work of the Ogallala Water CAP, Dr. Bailey hopes to develop and apply regional-​scale hydrologic models that can determine the effect of production systems and a variable climate on groundwater supply in future decades.

Success for this project means identifying best management and irrigation practices that can conserve groundwater in the Ogallala Aquifer Region (OAR) for future generations. This will serve the growers, groundwater management districts, and communities of the OAR. 

Opportunities. I would like to apply hydrologic models to large river basins within the Ogallala Aquifer Region (OAR), particularly the Republican River Basin. Also, I would like to incorporate the DSSAT crop model into the hydrologic modeling framework to more accurately depict the near-​surface hydrologic cycle and irrigation practices. These opportunities will mitigate groundwater depletions in the OAR.


Ryan Bailey, Ph.D.

Selected Publications

Gates, T.K., Cody, B.M., Donnelly, J.P., Herting, A.W., Bailey, R.T., and Mueller.-Price, J. (2009), Assessing selenium contamination in the irrigated stream-​aquifer system of the Arkansas River, Colorado. Journal of Environmental Quality 38, 1-13.

Bailey, R.T. and Baù, D. (2010), Ensemble smoother assimilation of hydraulic head and return flow data to estimate hydraulic conductivity distribution, Water Resources Research, 46, W12543, doi:10.1029/2010WR009147.

Bailey, R.T. and Baù, D. (2011), Estimating spatially-​variable first-​order rate constants in groundwater reactive transport systems, Journal of Contaminant Hydrology, 122, 104-121.

Bailey, R.T., and Baù, D. (2012), Estimating geostatistical parameters and spatially-​variable hydraulic conductivity within a catchment system using an ensemble smoother. Hydrology and Earth System Sciences, 16, 287-304.

Bailey, R.T., Hunter, W.J., and Gates, T.K. (2012), The influence of nitrate on selenium in irrigated agricultural groundwater systems. Journal of Environmental Quality, 41, 783-792.

Bailey, R.T., Baù, D., and Gates, T.K. (2012), Estimating spatially-​variable rate constants of denitrification in an irrigated agricultural groundwater system using an Ensemble Smoother. Journal of Hydrology, 468-​469, 188-202. 

Morway, E.D., Niswonger, R., Langevin, C., Bailey, R.T., and Healy, R. (2013), Modeling variably saturated subsurface solute transport with MODFLOW-​UZF and MT3DMS. Groundwater, 51(2), 237-251.

Bailey, R.T., Gates, T.K., and Halvorson, A.D. (2013) Simulating variably-​saturated reactive transport of selenium and nitrogen in agricultural groundwater systems. Journal of Contaminant Hydrology, 149, 27-45. 

Bailey, R.T., Morway, E.D., Niswonger, R., and Gates, T.K. (2013), Modeling variably saturated multispecies reactive groundwater solute transport with MODFLOW-​UZF and RT3D. Groundwater, 51(5), 752-761.

Bailey, R.T. and M. Ahmadi (2014), Spatial and Temporal Variability of In-​Stream Water Quality Parameter Influence on Dissolved Oxygen and Nitrate within a Regional Stream Network. Ecological Modelling 277, 87-96. 

Bailey, R.T., Gates, T.K., and M. Ahmadi (2014), Simulating reactive transport of selenium coupled with nitrogen in a regional-​scale irrigated groundwater system. Journal of Hydrology515, 29-46. 

Yen, H., Bailey, R.T., Arabi, M., Ahmadi, M., White, M., and Arnold, J. (2014), The role of interior watershed processes in improving parameter estimating and performance of watershed models. Journal of Environmental Quality, doi:10.2134/jeq2013.03.0110.

Bailey, R.T., Romero, E.C., and T.K. Gates (2015), Assessing best management practices for remediation of selenium loading in groundwater to streams in an irrigated region. Journal of Hydrology. 521:341-359.

Foy, C., Arabi, M, Yen, H, Gironás, J., and R.T. Bailey (2015), Multisite assessment of hydrologic processes in snow-​dominated mountainous river basins in Colorado using a watershed model. Journal of Hydrologic Engineering. doi: 10.1061/(ASCE)HE.1943-5584.0001130.

Bailey, R.T., Gates, T.K., and E.C. Romero (2015), Assessing the effectiveness of land and water management practices on nonpoint source nitrate levels in an alluvial stream-​aquifer system. Journal of Contaminant Hydrology. 179, 102-115. 

Bailey, R.T., Ahmadi, M., Gates, T.K. and M. Arabi (2015), Spatially distributed influence of agro-​environmental factors governing nitrate fate and transport in an irrigated stream-​aquifer system. Hydrology and Earth System Sciences, 19, 4859-​4876. doi: 10.5194/hess-19-4859-2015.

Bailey, R.T., Wible, T.C., Arabi, M., Records, R.M., and J. Ditty (2016), Assessing regional-​scale spatio-​temporal patterns of groundwater-​surface water interactions using a coupled SWAT-​MODFLOW model. Hydrological Processes, doi: 10.1002/hyp.10933.

Sharp, M.D., Hoag, D.L.K., Bailey, R.T., Romero, E.C., and T.K. Gates(2016), Institutional Constraints on Cost-​Effective Water Management: Selenium Contamination in Colorado’s Lower Arkansas River Valley. Journal of the American Water Resources Association. Accepted for publication.

Bailey, R.T. (2016), Review: selenium contamination, fate, and reactive transport in groundwater in relation to human health. Hydrogeology Journal. Accepted for publication.

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