2007 Ground Water Summit

Wednesday, May 2, 2007 : 2:20 p.m.

Impacts of Climate Change on Mountain-Front Recharge: Implications for Water Manangement

Karen MacClune, Ph.D.1, Dagmar Llewellyn2 and Jungyill Choi1, (1)SS Papadopulos & Associates Inc., (2)SS Papadopulos and Associates Inc.

Climate change has the potential to reduce mountain-front groundwater recharge via:

·        increased temperatures causing a greater percentage of annual precipitation to fall as rain rather than snow, resulting in faster runoff and less infiltration;

·        changes in precipitation intensity resulting in a shift in the runoff to infiltration ratio;

·        changes in the quantity of received precipitation, and,

·        increased temperatures resulting in increased evaporation and evapotranspiration.

 

This paper evaluates the potential impacts of these changes on recharge rates in the Upper Klamath Basin in Oregon, using several readily available modeling tools.  The selected methodologies have the advantages of ease of application, requiring materials readily available for the conterminous United States, to secure an initial evaluation of the potential impacts of various climate change scenarios to groundwater resources within a basin.

 

A simple model was developed to evaluate the potential effect of increases in temperature on groundwater recharge for a test site in the Upper Klamath River Basin.  Gridded maximum, minimum, and mean temperature data was used in conjunction with a digital elevation model to calculate potential ET for the basin.  A matrix of PRISM annual average precipitation data was then used to calculate net groundwater recharge taking into account potential ET and basin outflow.  Results indicate significant reductions in groundwater recharge resulting from relatively small increases in temperature.  The potential effects of changes in the type (snow or rain) and intensity of precipitation are being evaluated through application of components of the EPA’s BASINS modeling framework (HSPF and the associated Climate Assessment Tool).  Used together these tools allow us to evaluate the relative significance of these potential drivers to overall infiltration rates.

 

 

Karen MacClune, Ph.D., SS Papadopulos & Associates Inc. Dr. MacClune has been involved in basin-scale hydrologic assessment and modeling for over 12 years. Since joining SSPA, Dr. MacClune has been involved in: conjunctive groundwater/surface-water water budget quantification; groundwater modeling and groundwater supply analysis; assessment of impacts to water resources resulting from conversion from surface to groundwater irrigation; assembly of a comprehensive water quality database for use in litigation; work with regional water planners to develop hydrologically realistic water planning options and to assess basin-wide impact of proposed water planning alternatives; and, application of past and projected future climatic data to questions of water availability and demand. Prior to her time with SSP&A, Dr. MacClune was a member of the National Science Foundation Long Term Ecological Research Project in the McMurdo Dry Valleys, Antarctica, where she was responsible for quantifying the effects of climate and climate change on surface water flows within the valley. Dr. MacClune’s work uniquely qualifies her for basin-wide water resource assessment and development of water management alternatives to maximize supply for multiple stakeholder, taking into account projected climate change impacts on water supply, water demand, and land use.

Dagmar Llewellyn, SS Papadopulos and Associates Inc. In her over 20 years of experience as a consulting hydrologist, Ms. Llewellyn has managed numerous large projects involving field investigation, analysis and numerical modeling of hydrologic conditions. Based in Albuquerque, New Mexico over the past five years, Ms. Llewellyn has served as on-site coordinator for SSPA’s work in New Mexico. Ms. Llewellyn has represented the New Mexico Attorney General’s office in the Middle Rio Grande ESA Collaborative Program Water Acquisition and Management Committee, chairing that committee for a year and a half. She recently served as Project Manager for numerous hydrologic investigations of the Rio Grande, including an investigation of irrigation efficiency within the conservancy district in the Middle Rio Grande, support for an environmental impact statement on river and reservoir operations, extensive field studies of river, irrigation canal, and drain seepage losses, and application of these data to surface-water/groundwater modeling. Ms. Llewellyn manages a program of river monitoring to assist with river system operations to maintain flows for the endangered Silvery Minnow, and provides technical support to the Interstate Stream Commission related to Minnow litigation.


The 2007 Ground Water Summit