(last updated November 2008)

Overview

''As our technological and research capacity increases, along with the footprint of human activity, we are faced with both the promise of understanding the environment and our relationship to it, and the responsibility of making wise decisions about the design and use of technology and about managing the complex relationships among people, ecosystems, and planetary processes.''
[Pfirman, S., and the AC-ERE, 2003, Complex Environmental Systems: Synthesis for Earth, Life, and Society in the 21st Century, A report summarizing a 10-year outlook in environmental research and education for the National Science Foundation, 68 pp.]

Surface and ground waters are an integral part of our environment. They significantly affect plant and animal ecology, provide resources for human use and consumption, and if mismanaged can pose serious hazards. Of course, the use and impacts of surface and ground water resources are affected not only by the quantity of water present, but also its quality. We face challenging questions regarding the development of our world's water resources; as outlined in the recent World Water Development Report (United Nations, 2003), today's priorities include providing clean water and sanitation, protecting ecosystems, and securing food, especially in developing parts of the world. An understanding of and ability to predict the movement of water and its constituents through the environment is essential to meeting these objectives.

I view my research as an opportunity to make manifest my commitment to the environment through continually acquiring engineering and analytical skills and applying them to new challenges. The overarching goal of my work is to improve understanding and representation of hydrologic processes to facilitate informed decision-making. Doing so requires the interpretation of measurements, the development of process understanding, and the creation of quantitative models. I am intrigued by the interactions between one's modeling goals and tolerance for uncertainty, one's characterization of the temporal and spatial variability of environmental parameters and representation of the physical processes, and the amount and quality of available information. While I anticipate undertaking many research projects with a variety of applications throughout the course of my career, I expect that these fundamental interests will motivate much of my work.

As a member of Smith College, I take on the additional commitment to introduce undergraduates to the excitement and challenge of engineering research. I seek to create experiences that integrate fundamental hydrologic questions with issues of human and ecosystem development and that provide rich learning opportunities for students. Beyond the immediate benefits to my scholarship and student development, these activities also contribute to the creation of a society informed of the value of engineering research.

Cloud Forest Hydrology

Tropical montane cloud forests (TMCFs) are ecosystems of extraordinary biological diversity whose existence depends on frequent immersion in clouds and mist. The interception of this cloud water strongly couples the ecology and hydrology of these forests. The occurrence of these forests in headwater regions makes them important recharge areas, especially during dry seasons when cloud-water interception may be a significant hydrologic input. Monteverde, Costa Rica harbors highland TMCFs that exemplify the delicate balances among climate, hydrology, habitat, and development. This region has received significant attention from the biological community and is undergoing rapid development as an ecotourist destination. To address the dual needs of development and conservation, the residents of Monteverde established the Monteverde Institute (MVI) in 1986 to blend research with educational opportunities for local Monteverde communities. However, despite the abundant biological research in Monteverde - and the recognition of the hydrologic cycle in sustaining TMCF ecology - the characterization and quantification of hydrologic fluxes, and of cloud-water interception in particular, remains a major future challenge. While it is generally accepted that the presence of forest vegetation enhances watershed recharge in these environments, the contribution of cloud-water interception to the regional water cycle and its temporal and spatial variability is poorly quantified. Basic questions to be answered include, How does precipitation vary in time and space along the Pacific slope? Does vegetation cover affect the hydrologic inputs to a watershed? What is the importance of cloud-water interception relative to rainfall? How does that importance vary with season? Do the travel histories and formation conditions of rain and fog lead to different isotopic signatures? Can geochemical methods be used to quantify cloud water added to the ecosystem? What is the impact of development on water quality and distribution? How does this impact affect the ecology of the region? To answer these questions, I am collaborating with Professor Amy Rhodes from the Geology Department, a teaming that combines my skills as a theoretical hydrologist with Amy's expertise in field work and aqueous geochemistry. Through novel combinations of physical and geochemical measurements, we seek to elucidate the distribution, availability, and quality of water in Monteverde, leading to better protection and management of the biologic and hydrologic resources in this valuable and sensitive environment.

Photos from recent trips.


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Meteorological Station

In June 2004, we installed a Campbell-Scientific Met Station on the roof of the Monteverde Institute (see photo). Monthly meteorological summaries are given below. We take care to ensure the accuracy of these data, but cannot offer any guarantees. If you use these data in a publication, please cite the appropriate meteorological reports (below) or contact me for further assistance. If you would like to use these data for educational purposes, you are welcome to do so.

This Readme file describes the data contained in the summaries.

2004 Meteorological Report (pdf)
Jun | Jul | Aug | Sep | Oct | Nov | Dec

2005 Meteorological Report (pdf)
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2006 Meteorological Report (pdf)
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2007 Meteorological Report (pdf)
In 2007, the recording tipping-bucket rain gauge was not working properly during three periods (1 March through 19 June, 18 September through 3 October, and 5 November through 31 December). The temperature and relative humidity probe was not working properly from 27 October through 22 November.
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |

2007 data from the manual rain gauge (collected by Marlene Campbell Leiton) are given here

Results Dissemination

Rhodes, A. L., A. J. Guswa, and S. E. Newell '04, in press. Using stable isotopes to identify orographic precipitation events in Monteverde, Costa Rica. In: Bruijnzeel, L. A., Juvik, J., Scatena, F. N., Hamilton, L. S., and Bubb, P. (eds.), Forests in the Mist: Science for Conservation and Management of Tropical Montane Cloud Forests, University of Hawaii Press.

Rhodes, A. L., A. J. Guswa, S. Dallas, E. M. Kim '02, S. Katchpole '02, and A. Pufall, in press. Water quality in a tropical montane cloud forest, Monteverde, Costa Rica. In: Bruijnzeel, L. A., Juvik, J., Scatena, F. N., Hamilton, L. S., and Bubb, P. (eds.), Forests in the Mist: Science for Conservation and Management of Tropical Montane Cloud Forests, University of Hawaii Press.

Guswa, Andrew J. and A. L. Rhodes, 2008. Meteorology of Monteverde, Costa Rica, 2007. Technical Report submitted to the Monteverde Institute, 29 pages. (pdf version)

Guswa, Andrew J., A. L. Rhodes, S. E. Newell '04, 2007. Importance of dry-season orographic precipitation to the water resources of Monteverde, Costa Rica, Advances in Water Resources, 30, 2098-2112, doi:10.1016/j.advwatres.2006.07.008. (pdf version)

Guswa, Andrew J. and A. L. Rhodes, 2007. Meteorology of Monteverde, Costa Rica 2006. Technical Report submitted to the Monteverde Institute, 33 pages. (pdf version)

Guswa, Andrew J. and A. L. Rhodes, 2007. Ecohydrology and Water Resources of Monteverde, Costa Rica: Implications of a Changing Climate, MA Water Resources Research Center, 4th Annual Conference, Sustainable Waters in a Changing World: Research to Practice, Proceedings, University of Massachusetts, Amherst, MA, 9 April.

June K. Yeung '07, A. J. Guswa, 2007. Rainfall-runoff modeling for a small headwater catchment in Monteverde, Costa Rica, MA Water Resources Research Center, 4th Annual Conference, Sustainable Waters in a Changing World: Research to Practice, Poster, University of Massachusetts, Amherst, MA, 9 April.

Rhodes, A. L., A. J. Guswa, and S. E. Newell '04, 2006. Seasonal variation in the stable isotopic composition of precipitation in the tropical montane forests of Monteverde, Costa Rica, Water Resources Research, 42, W11402, doi:10.1029/2005WR004535.

Yeung, June K. '07, A. J. Guswa, and A. L. Rhodes, 2006. Streamflow report for the Quebrada Cuecha in Monteverde, Costa Rica, June 2004 - April 2006. Technical report submitted to the Monteverde Institute.(pdf version)

Guswa, Andrew J. and A. L. Rhodes, 2006. Meteorology of Monteverde, Costa Rica 2005. Technical Report submitted to the Monteverde Institute, 34 pages. (pdf version)

Guswa, Andrew J. and A. L. Rhodes, 2005. Importance of dry-season precipitation to the water resources of Monteverde, Costa Rica, Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract H54C-03.

Rhodes, Amy L., A. J. Guswa, and S. E. Newell '04, 2005. Seasonal variation in the stable isotopic composition of precipitation in the tropical montane forests of Monteverde, Costa Rica, Eos Trans. AGU, 85(52), Fall Meet. Suppl., Abstract H43E-0533.

Guswa, Andrew J., 2005. Mountains in the mist: Characterization of hydrologic fluxes in Monteverde, Costa Rica. Proceedings of the 3rd CNR-Princeton Workshop on New Frontiers in Hydrology, Princeton, NJ, May 17-20, 2005.

Johnson, Ilona R. '06, A. J. Guswa, A. L. Rhodes, 2005. Meteorology of Monteverde, Costa Rica, November 2003-November 2004. Technical Report submitted to the Monteverde Institute, 23 pages. (pdf version)

Guswa, Andrew J., Rhodes, A. L., 2004. Wet-season throughfall in primary and secondary tropical montane cloud forests, Monteverde, Costa Rica, Eos Trans. AGU, 85(47), Fall Meeting Suppl., Abstract H54C-05. (pdf of presentation)

Rhodes, A. L., A. J. Guswa, and S. E. Newell '04, 2004. Using stable isotopes to trace orographic precipitation in a tropical montane cloud forest, Monteverde, Costa Rica. Eos Trans. AGU, 85(47), Fall Meeting Suppl., Abstract H54C-05.

Guswa, Andrew J. and A. L. Rhodes, 2004. Unique benefits of involving undergraduates in tropical montane cloud forest research: A case study from Smith College, Forests in the Mist: Science for Conservation and Management of Tropical Montane Cloud Forests, Hawaii, July 27 - August 2, 2004.

Rhodes, A. L., A. J. Guswa, S. Dallas, E. M. Kim '02, S. Katchpole '02, S. E. Newell '04, A. Pufall, 2004. Water quality of a tropical montane cloud forest watershed, Monteverde, Costa Rica, Eos Trans. AGU, 85(17), Joint Assembly Suppl., Abstract H23B-13.

Guswa, Andrew J., and A. L. Rhodes, 2003. Successful undergraduate research: Creating win-win-win, Eos Trans. AGU, 84(46), Fall Meeting Suppl., Abstract ED11B-0105.

Ecohydrologic Modeling

Ecohydrology is the investigation of the hydrologic mechanisms that underlie ecologic patterns and processes. This broad definition includes a variety of interactions among hydrologic processes and plant and animal communities. An important aspect is the quantitative prediction of the linkages among climate, soil-moisture dynamics, and vegetation in natural water-limited ecosystems. Vegetation health in such environments depends on a complex interplay among the timing and amount of precipitation and the dynamics of infiltration and evapotranspiration. Effective models of these interactions enable us to predict the responses of these sensitive ecosystems to a changing global environment. Exciting questions include, What levels of spatial and temporal resolution are required to represent plant vitality in these environments? How can the appropriate degree of model complexity be determined from environmental characteristics and study objectives? If one has limited information regarding soil moisture (such as what can be obtained from remote sensing satellites), how can it be used to infer a more complete understanding of soil-moisture dynamics? I look to answer these questions through theoretical analyses and modeling studies.
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Results Dissemination

Guswa, Andrew J., 2008. Effect of plant-uptake representation on the water-optimal root depth, Eos Trans. AGU, 89(53), Fall Meeting Suppl., Abstract H13E-0967.

Guswa, Andrew J., 2008. Response of root depth to climate: A hydrologist's view of the critical zone, Geological Society of America Annual Meeting, Abstracts with Programs, 40(6), 56-4.

Guswa, Andrew J., 2008. The effect of precipitation variability on root depth and the partitioning of hydrologic fluxes, MA Water Resources Research Center, 5th Annual Conference, Integrating Water Resources Management, Proceedings, University of Massachusetts, Amherst, MA, 8 April 2008.

Guswa, Andrew J., 2008. The influence of climate on root depth: A carbon cost-benefit analysis, Water Resources Research, 44, W02427, doi:10.1029/2007WR006384. (pdf version)

Guswa, Andrew J., 2006. The influence of climate on root depth, Eos Trans. AGU, 87(52), Fall Meet. Suppl., Abstract B41E-235. (MS PowerPoint poster)

Puma, M. J., I. Rodriguez-Iturbe, M. A. Celia, and A. J. Guswa, 2006. Implications of rainfall temporal resolution for soil-moisture and transpiration modeling, Transport in Porous Media.

Puma, Michael A., I. Rodriguez-Iturbe, M. A. Celia, J. M. Nordbotten, and A. J. Guswa, 2005. Effects of spatial heterogeneity in rainfall and vegetation on the space-time scaling of soil-moisture and evapotranspiration, Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract B33D-1056.

Celia, M. A., I. Rodriguez-Iturbe, A. J. Guswa, J. M. Nordbotten, M. J. Puma, 2005. Representation of soil moisture, evapotranspiration, and solute transport across different length and time scales, Eos Trans. AGU, 86(18), Joint Assembly Suppl., Abstract H42A-01.

Guswa, Andrew J., 2005. Soil-moisture limits on plant uptake: An upscaled relationship for water-limited ecosystems, Advances in Water Resources, 28(6), 543-552. (pdf version)

Puma, M. J., M. A. Celia, I. Rodriguez-Iturbe, and A. J. Guswa, 2005. Functional relationship to describe temporal statistics of soil moisture averaged over different depths, Advances in Water Resources, 28(6), 553-566.

Guswa, Andrew J., M. A. Celia, and I. Rodriguez-Iturbe, 2004. Effect of vertical resolution on predictions of transpiration in water-limited ecosystems, Advances in Water Resources, 27(5), 467-480. (pdf version)

Guswa, Andrew J., M. A. Celia, and I. Rodriguez-Iturbe, 2003. Effect of model resolution on predictions of vegetation health in water-limited ecosystems, Eos Trans. AGU, 84 (46), Fall Meeting Suppl., Abstract H42H-01.

Puma, Michael J., M. A. Celia, I. Rodriguez-Iturbe, A. J. Guswa, 2003. Functional relationship to describe temporal statistics of soil moisture averaged over different depths, Eos Trans. AGU, 84(46), Fall Meeting Suppl., Abstract H42H-02.

Guswa, Andrew J. Soil-moisture limits on plant water uptake: A multivalued upscaled relationship for water-limited ecosystems, Proceedings of the 2nd CNR-Princeton Workshop on New Frontiers in Hydrology, Capri, Italy, October 22-24, 2003.

Guswa, Andrew J., M. A. Celia, and I. Rodriguez-Iturbe, 2002. Models of soil-moisture dynamics in ecohydrology: A comparative study, Water Resources Research, 38(9). (pdf version)

Guswa, Andrew J., I. Rodriguez-Iturbe, and M. A. Celia, 2002. Soil-moisture dynamics and plant uptake in water-limited ecosystems: Process representation and model scale, Proceedings of the 1st CNR-Princeton Workshop on New Frontiers in Hydrology, Princeton University, October 23-25, 2002.

Celia, Michael A. and A. J. Guswa, 2002. Hysteresis and upscaling in two-phase flow through porous media, Contemporary Mathematics, 295, 93-104.

Guswa, Andrew J., Celia, M. A., and Rodriguez-Iturbe, I., 2001. Comparison of infiltration models for evaluating vegetation stress in water-controlled ecosystems, [Abstract], Eos Trans. American Geophysical Union, Vol 82, No 20.

Northeast Ecohydrology

Ecohydrology is the investigation of the hydrologic mechanisms that underlie ecologic patterns and processes. This broad definition includes a variety of interactions among hydrologic processes and plant and animal communities. To quantify these interactions, we are developing a field site in Whately, MA as part of Smith College's initiative to establish a Center for the Environment, Ecological Design, and Sustainability. This site is currently the location of an AirMAP monitoring station, and supports an eighty-foot tower that extends above the canopy. We intend to install precipitation gauges, soil-moisture and soil-temperature sensors, and instruments to measure sap flux in the near future.

Additionally, Prof. Amy Rhodes and I are conducting an investigation of the fate and transport of road salt through a calcareous fen in Stockbridge, Massachusetts. Salt applied to the Massachusetts Turnpike during the winter months is passes through this Area of Critical Environmental Concern, with some of the salt sorbing to the soils and peat. Questions of interest include, How much of the annual salt application is flushed through the wetland? What is the rate of accumulation of salt in the fen? Is the presence of salt facilitating an invasion by Phragmites australis? We seek to better understand the ecohydrology of this system through observations in the field, data analysis, and quantitative modeling.
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Results Dissemination

Rhodes, Amy L., A. J. Guswa, 2008. Geochemical response of a calcareous fen to road salt contamination during snow melt and precipitation events: Kampoosa Bog, Stockbridge, MA, Eos Trans. AGU, 89(53), Fall Meeting Suppl., Abstract H33F-1084.

Rhodes, Amy L. A. J. Guswa, A. Pufall, 2008. Hydrogeochemistry of Kampoosa Bog, Final Report to the Massachusetts Environmental Trust, 15 June 2008, 75 pages.

Rhodes, Amy L., A. J. Guswa, A. Pufall, 2008. Fate and transport of road salt during snowmelt through a calcareous fen: Kampoosa Bog, Stockbridge, Massachusetts, MA Water Resources Research Center, 5th Annual Conference, Integrating Water Resources Management, Proceedings, University of Massachusetts, Amherst, MA, 8 April 2008.

Alex Webster '08, A. J. Guswa, V. Hayssen, 2008. Effect of stand characteristics on throughfall in a New England forest, MA Water Resources Research Center, 5th Annual Conference, Integrating Water Resources Management, Proceedings, University of Massachusetts, Amherst, MA, 8 April 2008.

Rhodes, Amy L., A. J. Guswa, and A. Pufall, 2007. Fate and transport of road salt during snowmelt through a calcareous fen: Kampoosa Bog, Stockbridge, Massachusetts, Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract H21I-03.

Geologic Heterogeneity and Subsurface Contaminant Transport

Full description for the lay reader (pdf format)

Geologic spatial variability affects the fate and transport of solutes in the subsurface. When addressing problems of groundwater contamination, there are often specific questions. How long will it take to clean up a site? When will this contaminant reach a water supply well? The objective is not, therefore, to represent all of the complexity and variability of the subsurface, but rather to identify those aspects that have a significant impact on the goal at hand and to capture those effects efficiently and accurately. My work has focused on the effects of rate-limited mass transfer and heterogeneity on groundwater solute transport. I initially explored the differences in the behavior of solute tailing due to differences in the nature of transport through an isolated low-permeability inclusion (diffusion dominated versus advection dominated). I later extended this work and developed a parameter to indicate the need for a model beyond the advection-dispersion equation to account for extended solute tailing in environments with low-permeability lenses. Along these lines, I see avenues for future research in extending this work to more realistic geologic media. Through numerical experiments, I am interested in exploring these questions in order to more effectively describe and predict the extent of solute tailing in heterogeneous environments.
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Results Dissemination

Guswa, Andrew J., and D. L. Freyberg, 2002. On using the equivalent conductivity to describe solute spreading in geologic environments with low-permeability lenses, Water Resources Research, 38(8).

Guswa, Andrew J., and D.L. Freyberg, 2000. Evaluation of the Need for a Mass-Transfer Model to Describe Solute Tailing due to Low-Permeability Lenses, [Abstract], Eos Trans. American Geophysical Union, Vol. 81, No. 48, F435.

Guswa, Andrew J., and D. L. Freyberg, 2000. Slow advection and diffusion through low permeability inclusions, Journal of Contaminant Hydrology, 46 (3-4), 205-232.

Guswa, Andrew J., J.A. Cunningham, and D.L. Freyberg, 1999. A Two-Region Model to Account for Slow Advection through Low Permeability Lenses,” [Abstract], Eos Trans. American Geophysical Union, Vol. 80, No. 46, p. F389.

Guswa, Andrew J., and D.L. Freyberg, 1998. Transport Effects of Diffusion and Slow Advection Through a Low Permeability Inclusion, [Abstract], Eos Trans. American Geophysical Union, Vol. 79, No. 45, p. F392.

Guswa, Andrew J., D.L. Freyberg, and P.V. Roberts, 1997. Characterization of Regions of Low Peclet Number in Complex Geologic Environments, [Abstract], Eos Trans. American Geophysical Union, Vol. 78, No. 46, p. F293.

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