Presenter: Katharine Jacobs, Director of the Arizona Water Institute, University of Arizona
37 slide

Jacobs, Katharine

English

Colorado Law

University of Colorado Law School Colorado Law Scholarly Commons Western Water Law, Policy and Management: Ripples, Currents, and New Channels for Inquiry (Martz Summer Conference, June 3-5) 2009 6-3-2009 SLIDES: Groundwater Declines, Climate Change and Approaches to Adaptation Katharine Jacobs Follow this and additional works at: https://scholar.law.colorado.edu/western-water-law-policy-and-management  Part of the Administrative Law Commons, Agriculture Law Commons, Aquaculture and Fisheries Commons, Biodiversity Commons, Climate Commons, Energy and Utilities Law Commons, Energy Policy Commons, Environmental Health and Protection Commons, Environmental Law Commons, Environmental Policy Commons, Forest Management Commons, Hydraulic Engineering Commons, Hydrology Commons, Indian and Aboriginal Law Commons, Jurisdiction Commons, Land Use Law Commons, Litigation Commons, Natural Resource Economics Commons, Natural Resources and Conservation Commons, Natural Resources Law Commons, Natural Resources Management and Policy Commons, President/Executive Department Commons, Property Law and Real Estate Commons, Public Policy Commons, Risk Analysis Commons, Science and Technology Law Commons, State and Local Government Law Commons, Water Law Commons, and the Water Resource Management Commons Citation Information Jacobs, Katharine, "SLIDES: Groundwater Declines, Climate Change and Approaches to Adaptation" (2009). Western Water Law, Policy and Management: Ripples, Currents, and New Channels for Inquiry (Martz Summer Conference, June 3-5). https://scholar.law.colorado.edu/western-water-law-policy-and-management/18 Reproduced with permission of the Getches-Wilkinson Center for Natural Resources, Energy, and the Environment (formerly the Natural Resources Law Center) at the University of Colorado Law School. Groundwater Declines, Climate Change and Approaches to AdaptationKatharine Jacobs, DirectorArizona Water InstituteWestern Water Law, Policy and ManagementNatural Resources Law Center ConferenceBoulder, ColoradoJune 3, 2009Shearsensibility.blogspot.comWith thanks to Stan Leake, USGSThe role of groundwater in an age of increasing variability• Groundwater declines as a measure of existing stress• Implications of climate change for water supplies generally• Implications for groundwater specifically• Arizona case study• Adaptation options – a thought experimentGroundwater declinesSource: International Water Management Institute (IWMI)DETAIL 2: “...groundwater depletion is a phenomenon of the twentieth century, made possible by the availability of electricity and cheap pumps.”Groundwater depletion - USGS“Ground water is a valuable resource both in the United States and throughout the world. Where surface water, such as lakes and rivers, are scarce or inaccessible, ground water supplies many of the hydrologic needs of people everywhere. In the United States it is the source of drinking water for about half the total population and nearly all of the rural population, and it provides over 50 billion gallons per day for agricultural needs.”Groundwater declines in the OgallalaWater levels in the high plains have declined up to 170 feet (Ogallala Aquifer)USGS 2007-3029Groundwater declines in the SouthwestLeake et al., 2000 USGSMining groundwater leads to…• Lowering of the groundwater table• Higher pumping costs and well deepening• Impacts on surrounding wells• Poorer water quality• Impacts on riparian areas• Subsidence of the land surface• Economic concernsRadar interferogram 1997 to 2000News from the International Panel on CC• Warming is “unequivocal’• The Southwest is getting drier• The impacts are more visible• The mechanisms are better understood, especially in winterIncreased Climate Stress in Mid-latitudesGroundwater DeclinesSource: International Water Management Institute (IWMI)DETAIL 2: “...groundwater depletion is a phenomenon of the twentieth century, made possible by the availability of electricity and cheap pumps.”Impacts of Climate Change on Water SectorClimate change will affect• Snowpack, rain vs. snow• Timing and seasonality of surface water runoff• Groundwater-surface water interactions• Water temperature• Water quality• Extreme events• Rate of change; thresholdsClimate Change Impacts on WaterSaturation curve showing the relationshipbetween vapor pressure and temperature•Temperature is a hydrologic variable affecting both supply and demandThe impact of temperature on water supply is non-linear• Projected climate change impacts on flows in the Colorado are significant; possible 20% reduction in runoff by 2050 (XRISA Study).30% chance of empty reservoirs by 2050Climate Change Impacts on WaterCalifornia – Poster Child for Overlying StressesAQUAFORNIACalifornia case … the importance of contextDecreased snowpack, significant change in runoff patternsIncreased salinity in coastal aquifersDelta management issues, sea level rise, subsidence, failing dikes, etcEndangered speciesWainger decision: institutional and legal constraintsWhat about effects on Groundwater? There are a lot more questions than there are answers…but • We know more about temperature than precipitation, and • We know that reductions in surface flows are likely to reduce recharge… EPA.govWhat about effects on Groundwater?• We know that when surface water is scarce that groundwater pumping rates increase…What we don’t know:• Implications of changes in seasonality of runoff on recharge rates?• Temporal and spatial changes in demand and supply?• Increased recharge during flood events?• Decreased recharge during   drought?• Changes in availability                                       of alternative supplies                                    (e.g. surface water, effluent)? EPA.govWhat we don’t know:• How will increases in fire frequency and magnitude affect sedimentation and recharge rates?• Changes in water quality, egfire, dust, sediment:  gw quality                            implications not clear?• Role of changes in vegetation                      in hydrologic cycle at the                landscape scale?AZ DEQ• Effects of changes in energy supplies and costs?  Availability of hydropower? • Will surface water shortages result in more groundwater pumping at a time when energy costs are increasing?• How will cap and trade or carbon tax affect the economics of water supply?• Global economic trends egshifts in agricultural                                 production?What we don’t know:NOAAIncreased Salinity and Groundwater?Implications of overdraft, reuse and sea level riseSalt Water Intrusion in US Aquifers, Clean Beta• Established Active Management Areas (AMAs)• Set long-range water  management goals (Safe Yield)• Established GW rights systemArizona Case Study - The 1980 Groundwater Management ActAMAs: Groundwater rights and permitsWell metering, annual reports and feesMandatory conservation for large usersAssured/adequate water supply for subdivisionsNo new agricultureADWRAMA Groundwater Management Plans• Every 10 years, though 2025• Increasingly stringent requirements for municipal water providers, farmers, large industrial users (mines, golf courses, electric power, etc).• Long-range projections of supply/demandCourtesy ADWRDraft 2005TAMAWater BudgetWhat are the implications of climate change on the water budget of the Tucson AMA?Potential Climate Change Impacts on Arizona Water Management Programs• Well spacing and well impact regulations• General Industrial Use Permits• Recharge Permits• Assured Water Supply Program• Adequate Water Supply Program• Management Plan Development• Safe-yield analyses• Watershed management activities, eg San Pedro sustainability goalWhy is the Assured/Adequate Water Supply Program so Important?• It requires the fastest                                         growing sector to use                               renewable supplies• It focuses on the sector                                 with the greatest ability to pay• In AMAs, it protects groundwater for future use• Heavily dependent on modeling physical availability of groundwater• Changes in reliability of surface water supplies – more focus on the “continuous availability” criterion – and on back-up supplies and drought planning• Increases in rate of water level declines• Increased number of “drought declarations”in which allowable groundwater pumping increases; implications for safe-yield• Need to increase long-term storage credits to firm M&I and Indian suppliesPotential Climate Change Impacts on AWSImpacts likely to Vary by Basin• Pinal AMA natural recharge and natural discharge (ET)  insignificant parts of the water budget in most years• Santa Cruz AMA water budget changes dramatically based on precipitation and flooding events• San Pedro goal - sustainability of flows - means slight changes in seasonality could have big impactsTransmission of Climate Signals through Groundwater Systems (Leake)Changes in flow from climate change could be seen rapidly in surface runoff, but timing of changes in groundwater systems is highly dependent on factors including– Changes in near-surface evapotranspiration– Time for changes in recharge to move through the unsaturated zone– Propagation of changes through the saturated zone to areas of groundwater dischargeTransmission of Climate Signals through Groundwater System– San Pedro model (2006)– Recharge at periphery– Discharge occurs in riparian system– Test - increased recharge by 25 percent, tracked changes in outflow through time – Analysis considers only saturated GW transmission USGS0 200 400 600 800 1000 1200 1400 16000510152025TIME SINCE CHANGE IN RECHARGE, IN YEARSPERCENT CHANGE IN FLOWRECHARGE50 %80 %CHADISRGELag Effect in Transmission of Climate Signals through Groundwater—San Pedro ResultsUSGSHowever, additional groundwater pumping in the context of climate change  could have a much more immediate effect…Groundwater Adaptation OpportunitiesProtection for groundwater-dependent users and riparian areas• Conservation?• Well spacing• Pumping limitations in vulnerable areas• Land use planning integrated with water supply– Zoning and easements– Transferable development rights– Assured water supply– Water harvesting and reuse• Recharge (and recovery)• Environmental flow banks (in a                 groundwater context)Adaptation: Tools for Connecting Land Use and Water SupplySan Pedro Capture Map Stan Leake, Don Pool, and Jim LeenhoutslUSGSGroundwater Adaptation to Climate Change• Acknowledge– Buffer value increases with scarcity and extremes– GW-SW connections– Higher ET leads to lower recharge– Aquifer storage, optimizing conjunctive use are key tools (but rely on surplus supplies)• Establish– Enforceable GW rights systems– Monitoring for Adaptive Management• Re-evaluate– Hydrologic assumptions: the past is not an analogue for the future– Engineering assumptions re: changes in means and extremes, potential for non-linear changesAdaptation Approaches and Policy Issues• Managing existing and future risk• Dealing with uncertainty: Avoiding analysis paralysis, focusing on what we do know rather than what we don’t, managing expectations• Acknowledging – Complexity and interconnectedness of social and environmental systems, implications for biodiversity– The global context– The role of economic incentives (and disincentives)– Potential for unintended consequences– The potential for crossing thresholdsAdaptation: Research• Understanding changes in the hydrologic cycle• Modeling surface water-groundwater connections• Overcoming institutional barriers to good management• Identifying monitoring and prediction needs for non-stationarityAdaptation: Research• Building credible future scenarios• Understanding:– How much water is enough for the environment– Energy implications for groundwater– Water quality impacts of climate changeFour focused panels will be convened to study and write separate in-depth reports on these four questions:1. What can be done to limit the magnitude of future climate change?2. What can be done to adapt to the impacts of climate change?3. What can be done to better understand climate change and its interactions with human and ecological systems?4. What can be done to inform effective decisions and actions related to climate change?The “Main Committee” will provide recommendations that integrate the work of the four panels

SLIDES: Groundwater Declines, Climate Change and Approaches to Adaptation

https://scholar.law.colorado.edu/cgi/viewcontent.cgi?article=1013&context=western-water-law-policy-and-management

SLIDES: Groundwater Declines, Climate Change and Approaches to Adaptation

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