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Overview of Water Resources Planning and Management Dr. Alan F. Hamlet •JISAO/CSES Climate Impacts Group •Dept. of Civil and Environmental Engineering University of Washington Water Resources Management is an Ancient Human Activity •Nomadic behavior •Use of springs and wells in shallow ground water near settlements •By about 300 AD, Rome had nine aquaducts feeding the city, totaling more 400 km in length. There were substantial dams, and use of hydropower (water wheels) appears to have been common. •Starting around 600 AD, the flow in the Nile was measured as means to forecasting water supply and potential harvest. Roman Flour Mill at Barbégal (present day France) ~400 AD Schematic of Dijon Public Fountain (~1850) By the mid-19th century, extensive engineering works to provide water supply had been constructed in some cities. These systems were very similar in many ways to modern systems with the exception of the distribution and water treatment systems. A famous example in Europe is the Dijon water supply system developed by Henry Darcy. Darcy also estimated water demand (about 35 gallons per person per day for domestic use, street sanitation). From the late 19th century to the early 20th century, as populations increased, water resources development reached unprecedented levels in the developed world. In the United States alone, there are currently more than I 8100 n major dams. Hoover Dam Water Resources is Linked to a Huge Number of Important Management and Socioeconomic Issues •Water supply •Food security •Human health •Ecosystem health and sustainability •Economic development •Energy production and energy use •Transportation (navigation) •Flooding and storm water management •Recreation •Drought impacts •Social equity and social justice •Education •Interstate and international relations •Urban development and planning •Industrial development •Water quality •Fire prevention Since the mid 1970s in the U.S. the basic elements of water resources planning have extended dramatically. Evolution of Columbia Basin Integration Boundaries Altered hydrologic response Creation of Lake systems in upper basin Displacement of people Beginning of major salmon impacts US Endangered Species Listings for Salmon Kootenay sturgeon threatened Columbia Basin Trust 1995 Biological Opinion Proposals for dam removal Columbia R. Treaty Flood Control Hydro Climate variability and change Aboriginal concerns Additional US ESA listings Transboundary issues Privatization of hydro ~1965 ~1975 ~1990 ~2000 Some Challenges for Water Management in the 21st Century •Growing human populations •Degradation of watersheds due to urbanization, etc. •Linkages between groundwater and surface water •Limited opportunities for infrastructure expansion •Increasing need to address ecosystem impacts and water quality •Complexity of multi-objective systems •Outdated planning and management paradigms (build it and leave it) •Climate Change Understanding Planning as a Process The primary objective of water resources planning is to create functionally robust and beneficial water resources management systems Water resources planning takes many forms and has many variations, and is perhaps best viewed as a process rather than a set of specific outcomes, because the specifics will vary so widely from case to case. The US Army Corps of Engineers, in their nicely written overview of the water resources planning, describe the planning process as an iterative sequence framed by six steps: •Identify Problems and Opportunities •Take Inventory and Forecast Resources •Formulate Alternative Plans •Evaluate Alternative Plans •Compare Alternative Plans •Select Preferred Alternatives Planning is an Iterative Process: Information acquired in the later steps of the sequence may identify key missing pieces in earlier steps which need to be addressed. For example, in the process of forecasting current and future resources, additional problems or opportunities may emerge that were not originally identified. Although useful as an introduction, the framework in the USACE planning manual is very generic, and it is often necessary to use case studies to gain some insight into how these techniques would actually be applied. Some Extreme Examples in Current Events: New Orleans Atlanta Colorado River Basin Water Resources Planning Research Climatological Foundation of U.S. Water Resources Planning and Management: 1) Risks are stationary in time. 2) Observed streamflow records are the best estimate of future variability. 3) Systems and operational paradigms that are robust to past variability are robust to future variability. Schematic of a Typical Water Planning Framework Observed Streamflows Planning Models System Drivers Annual streamflow reconstructions at The Dalles, OR using tree ring growth indices derived from douglas-fir and limber pine from SE British Columbia - Kamloops to Banff/Jasper (1750-1964) 350000 Columbia Basin Planning Window 300000 Observed Annual Streamflow Observed 5 yr mean 200000 Reconstructed Annual Streamflow Linear (Reconstructed Annual Streamflow) 150000 100000 y = -22.831x + 214682 50000 1975 1950 1925 1900 1875 1850 1825 1800 1775 0 1750 Flow (cfs) 250000 16.4 MAF was considered a conservative estimate at the time of the Compact. However, the average annual flow over the 20th century has been only 15 MAF. Relative to the gage record today, flows in the early 20th century appear to be unusually high. How unusual is this period in a longer-term context? (Figure Courtesy Connie Woodhouse) Tree rings placed the gage record in a long-term context Colorado River flow, reconstructed by Stockton and Jacoby, 1976 Stockton and Jacoby 1976 “…the timing of the drafting of the Compact was an unfortunate event, in that it did not occur during a representative flow period.” “The general picture of a collision between water demand and supply in the UCRB in the not-toodistant future is all too apparent.” Stockton and Jacoby 1976 (Figure Courtesy Connie Woodhouse) What’s the Problem? Despite a general awareness of these issues in the water planning community, there is growing evidence that future climate variability will not look like the past and that current planning activities, which frequently use a limited observed streamflow record to represent climate variability, are in danger of repeating the same kind of mistakes made more than 80 years ago in forging the Colorado River Compact. Long-term planning and specific agreements influenced by this planning (such as long-term water allocation agreements) should be informed by the best and most complete climate information available, but frequently they are not. The Myth of Stationarity Meets the Death of Stationarity Muir Glacier in Alaska Aug, 13, 1941 Aug, 31, 2004 Image Credit: National Snow and Ice Data Center, W. O. Field, B. F. Molnia http://nsidc.org/data/glacier_photo/special_high_res.html Simulated Changes in Natural Runoff Timing in the Naches River Basin Associated with 2 C Warming 120 Simulated Basin Avg Runoff (mm) 100 80 Impacts: •Increased winter flow •Earlier and reduced peak flows •Reduced summer flow volume •Reduced late summer low flow 1950 60 plus2c 40 20 0 oct nov dec jan feb mar apr may jun jul aug sep 2000 1996 1992 1988 1984 1980 1976 1972 1968 1964 1960 1956 1952 1948 1944 1940 CRB 1936 CA 1932 1928 3 1924 1920 1916 Std Anomalies Relative to 1961-1990 Regionally Averaged Cool Season Precipitation Anomalies 4 PNW PRECIP GB 2 1 0 -1 -2 -3 Changes in Simulated April 1 Snowpack for the Canadian and U.S. portions of the Columbia River basin (% change relative to current climate) 20th Century Climate “2040s” (+1.7 C) -3.6% -21.4% April 1 SWE (mm) “2060s” (+ 2.25 C) -11.5% -34.8% Rebalancing Water Systems in Response to Climate Change Some Conflicting Objectives Likely to be Impacted by Climate Change: •Hydropower and water supply vs. flood control •Hydropower and water supply vs. instream flow and ecosystem services. •Interstate and international transboundary agreements 8000 7000 6000 5000 4000 3000 2000 1000 0 Sep Full 25000 20000 15000 : Current Climate Sep Aug Jul Jun May Apr Mar Feb Jan Dec Nov 10000 Oct Storage Jul Aug Jun Apr May Mar Feb Jan Dec Oct 30000 Nov Reservoir Inflow Flood Control vs. Refill Flood Control vs. Refill Streamflow timing shifts can reduce the reliability of reservoir refill 8000 + 2.25 oC 6000 5000 4000 3000 30000 Full 2000 1000 25000 20000 15000 : Current Climate Sep Aug Jul Jun May Apr Mar Feb Jan Dec 10000 Nov : + 2.25 oC No adaptation Oct Storage Sep Jul Aug Jun Apr May Mar Jan Feb Dec Oct 0 Nov Reservoir Inflow 7000 Flood Control vs. Refill Streamflow timing shifts can reduce the reliability of reservoir refill 8000 7000 + 2.25 oC 5000 4000 30000 3000 Full 2000 1000 : Current Climate Storage Aug 25000 Sep Jul Jun Apr May Mar Jan Feb Dec Oct 0 Nov 20000 : + 2.25 oC No adaption 15000 Sep Aug Jul Jun May Apr Mar Feb Jan Dec 10000 Nov : + 2.25 oC plus adaption Oct Reservoir Inflow 6000 Major U.S. Flood Control Checkpoints Bonners Ferry Columbia Falls The Dalles Optimization Reduces Storage Deficits without Jeopardizing Flood Protection 2,000 Storage Deficits 1,500 optimized 1,000 500 Duncan Libby Mica Hungry Horse Dworshak Climate change/no adaptation 600 Flood Risks Flow at The Dalles (kcfs) Grand Coulee 0 Arrow July 31 Average Storage Deficit (KAF) Climate change/no adaptation 500 400 300 optimized 200 100 -2 -1 0 1 2 3 Extreme Value Type I Distribution Reduced Variate, Y 4 5 Adaptation Strategies Overview of Water Resources Adaptation Challenges: •Hydroclimatology •Systems Engineering and Water Resources Engineering Design •Institutional Considerations •Politics Approaches to Adaptation and Planning •Anticipate changes. Accept that the future climate will be substantially different than the past. •Use scenario based planning to evaluate options rather than the historic record. •Expect surprises and plan for flexibility and robustness in the face of uncertain changes rather than counting on one approach. •Plan for the long haul. Where possible, make adaptive responses and agreements “self tending” to avoid repetitive costs of intervention as impacts increase over time. Schematic of Climate Change Water Planning Framework Observed Streamflows Planning Models Altered Streamflows Climate Change Scenarios System Drivers Example of a Flexible, Self-Tending Reservoir Operating System •Improved Streamflow Forecasts Incorporating Warming and Other Features of Altered Climate System •Dynamic Reservoir Operating Systems Using Optimization or Hybrid Optimization/Simulation Approaches to Rebalance the System. •Such systems are more flexible and adaptable because they do not require a “trigger” for a change in the operating policies, and arguably do not require as much intervention as the climate system gradually changes, because the system responds autonomously to improvements in forecasts (whether related to climate change or other scientific advances) •These ideas are not really new: Harvard Water Program ~1965