The panel recognizes the body of scientific information available to support some actions within the BDCP. For example, the compilation of the Delta Regional Ecosystem Restoration Plan (DRERIP, see Appendix F in the draft BDCP) demonstrates that the community has invested considerable effort in establishing a scientific foundation for the numerous actions proposed in the draft BDCP. The participation of 50 analysts and scientists in the construction and scoring of the scientific evaluation worksheets indicates the large effort devoted to identifying ecologically founded actions. The massive DRERIP reflects the collective wisdom and insight of the region’s most knowledgeable and respected scientists.
However, it is not clear how the BDCP’s authors synthesized the foundation material and systematically incorporated it into the decision-making process that led to the suite of actions selected for implementation. As a unit, the draft BDCP combines a catalog of overwhelming detail with qualitative analyses of many separate actions that often appear disconnected and poorly integrated. Thus, although the biological descriptions and scenarios reflect a strong understanding of the scientific basis for many individual actions by the BDCP authors, there is no obvious distillation, synthesis and integration of the material into a cohesive decision-making process. The BDCP’s authors may have performed this critical exercise, but it is not described in the BDCP itself. The panel expects that the pending and critical effects analysis document could provide that convincing clarifying synthesis, relying on the DRERIP to provide the grist. Importantly, the participants who contributed to the DRERIP identified many uncertainties and deficiencies that need to be addressed by the community. Addressing these concerns presumably should happen before the plan is accepted as an ecologically sound path. The following excerpt from the DRERIP emphasizes these points:
“Collectively, the synthesis team concluded that a number of the conservation measures have the potential for additional synergistic effects that can raise or lower the value of some individual conservation measures when implemented concurrently with other actions. The complexity of various trade‐offs between expected positive and negative effects make it difficult to predict the biological responses to concurrent multiple measures. The Synthesis Team recommended that refinements could be made to the proposed modification of the Fremont Weir and Yolo Bypass inundation, North Delta diversions with bypass criteria, and Cache slough restoration to op
timize ecological benefits and water supply goals. They also identified the need for better information and modeling of the survival and growth of covered species and predators to establish baseline conditions against which benefits can be assessed…” (DRERIP, see Appendix F‐1 of the draft BDCP, p. 17).
This is just one example of the strong body of scientific information that is available to support specific actions within the plan. Nevertheless, there is a deficiency in the scientific synthesis that is needed to support the collective actions specified in the BDCP. Some examples of opportunities for demonstrating that scientific synthesis are described below.
The analyses for the Delta Risk Management Strategy (DRMS, 2009) have been performed to better understand the various risks to the integrity of levees and the local and statewide consequences of levee failure. Although there are limitations to this analysis, the results can offer guidance for prioritizing actions within the BDCP. For example, the DRMS study indicates that the benefits of the restorative conservation measures could be lost if levees failed and concludes that current levee management strategies in the Delta are unsustainable because of seismic risk, high water conditions, sea level rise and land subsidence. In addition to these broad conclusions, the report offers specific estimates of land impacts (e.g., economic costs of more than $15billion due to earthquake-derived levee failures and associated flooding of 20 islands)(DRMS, 2009).
California continues to invest in levee restoration, and additional restoration is included in the BDCP. However, levee repairs are not prioritized with regard to objectives such as habitat restoration, salinity management, drinking water protection, and preserving agriculture and historic Delta communities. Thus, any effects analysis should explicitly consider the interactions and tradeoffs between infrastructure and ecosystem goals. These interactions and tradeoffs may be considered in a risk-based framework, which could be complemented by analysis of the system reliability (the likelihood that a hydrosystem will fail to achieve some target), resilience (the ability of a system to accommodate, survive, and recover from unanticipated perturbation or disturbance), and vulnerability (the severity of the consequences of failure)(Fiering, 1982; Hashimoto, 1982; Moyle et al., 1986).
Furthermore, decision frameworks have recently been demonstrated in the Delta that highlight the economic tradeoffs of levee repair against the value of land and assets protected by those levees (Suddeth et al., 2010). The results suggest that, even with doubling of property values, repair of levees is not economically justifiable for most of the islands within the Delta's Primary Zone. Although decisions regarding levees, habitat, land use, and water alloca-
tions will certainly be based on more than economic motivations, the use of existing decision analysis tools, and development of new ones to address specific needs, may be invaluable in justifying prioritization of actions and geographical areas of emphasis within and outside of the Delta.
In developing such risk-based approaches, BDCP partners may also identify unacceptable outcomes and evaluate their likelihood, a task that would be valuable in comparing the ability of various management strategies to reduce the likelihood of hydrosystem deterioration, as has been suggested for climate change adaptation (NRC, 2010a). Therefore, the panel recommends that the BDCP partners select and apply a formal analytical framework to investigate the outcomes of proposed activities, including quantitative projections and existing science. Such an analysis―the effects analysis described in some detail above―should occur in advance of selecting the conservation and management actions, and should link specific restoration goals and undesirable system outcomes to the costs, benefits, and reliability of the proposed actions. To do so will require use of the extensive science developed in the basin, recognizing the limitations of its application and the implications of scientific uncertainty in prioritizing actions.
INTEGRATION OF CLIMATE CHANGE ANALYSIS
Climate change has been and will continue to be a major driver of hydrologic and landscape changes in the Delta. Projected changes in the primary drivers of climate change―namely rising temperatures, changing patterns of precipitation, and sea level rise―are expected to result in significant impacts to the ecosystems of both the Delta region and its tributary watersheds and will adversely impact the water supplies that are critical to both urban and agricultural users who depend on the Delta, the major reservoirs and the water conveyance systems (Chung et al., 2009). Therefore, climate change could pose significant threats to the success of the BDCP’s ecological goals and could increase the need for additional conservation measures such as construction of additional surface and aquifer storage facilities, demand management such as conservation programs and pricing, and changes in operating strategies (Lund et al., 2010), and it could affect economic factors and water operations (for example, Tanaka et al.,2008).
California’s climate change research has generated a wealth of information (Franco et al., 2008), which indicates potential impacts of climate change in the Delta region (e.g., Cayan et al., 2000; Climate Action Team, 2010; DWR, 2010; Field et al., 1999). The work to date has included a systems approach to understanding natural variability including (1) the potential global interconnections to the region’s climate (Gershunov et al., 2000; Redmond and Koch, 1991); (2) detection and attribution of historical change in climate (Bonfils et al., 2008); (3) quantification of potential changes in primary stressors of climate through analyses of general circulation model (GCM) predictions (Cayan et al., 2009) and
statistical downscaling (Hidalgo et al., 2008; Maurer and Hidalgo, 2008); (4) impacts of projected sea level rise (Knowles, 2008) and effects of rising temperatures on Delta water temperatures (Wagner et al., 2011); and (5) the sensitivity of the water resource system to climate change and sea level rise (USBR, 2008).
Although significant research on climate change vulnerabilities exists in the literature and in various reports produced by numerous agencies and institutions, the panel could not find evidence that such information has been used effectively in the development of the BDCP. Climate change analysis is legally required to obtain an incidental take permit, per NRDC vs. Kempthorne, 506 F.Supp.2d 322 (E.D. Cal. 2007). Yet the draft BDCP’s treatment of the topic of climate change, including warming and sea level rise, is fragmented: climate change is addressed only in the descriptions of existing biological conditions (Chapter 2), and sparsely in the Conservation Strategy section (Chapter 3). Furthermore, these discussions are limited to qualitative assessment of potential vulnerabilities and how the conservation strategy might be able to accommodate such impacts. The panel could not find a quantitative analysis of the specific hydrological and biological consequences of potential changes in the primary drivers and consequent changes in the tributary watersheds, aquifers, demands, risks of levee failure, and ecology of the BDCP plan area. Neither could the panel find a statement indicating that such analyses are not available or feasible at this scale. In spite of the brief quantitative summary of potential changes described in Section2.3.3.2 (pp. 2-36-2-37), there is no evidence that such estimates have been incorporated into the effects analysis and the design of conservation strategy elements. Chapter 5 of the draft BDCP (p. 5-3) says:
“The effects of climate change (e.g., sea level rise, temperature, and hydrology) were evaluated for early and late points in time of BDCP implementation based on climate change scenarios developed by the consultant team, technical staff from the lead agencies, and outside climate change experts (see Appendix K, Climate Change Evaluation Methods, for a discussion of this analysis),”
which appears to address some of the panel’s concerns. However, such information was not included in the draft BDCP that was provided.
In the presentation (“Incorporating Climate variability, Change, and Model Uncertainty in Scenarios for California Water Planning”) to the panel during its open session on December 8, 2010, Armin Munevar, a consultant from the firm CH2M HILL, did include the aforementioned analysis. A summary of this work appears in a December 2010 report entitled Climate Change Characterization and Analysis in California Water Resources Planning Studies (DWR, 2010, pp. 58-67). The climate change study of the BDCP is summarized in the above report and constitutes a reasonable approach for incorporating the current information regarding future climate projections, as predicted by the climate models, and the corresponding hydrologic impacts. Recognizing that precipitation projections are more uncertain (p. 2-36, draft BDCP) than temperature projections,
the BDCP’s approach includes five scenarios: (1) drier, less warming; (2) drier, more warming; (3) wetter, more warming; (4) wetter, less warming; and (5) a central tendency scenario, which aggregates the majority of model projections (DWR, 2010, p. 62). A further addition to this approach is the concept of the “nearest neighbor” method to select subgroups of models that represent the above five scenarios. Groups of GCM predictions and the corresponding down-scaled information demonstrate a significant spread in both precipitation and temperature, and the above approach of using five scenarios to select a set of model runs bracketing the potential changes in precipitation and temperature appears to be adequate until better methods become available.
The above scenarios for climate change and sea level rise have been combined with a variety of hydrologic, operational, and hydrodynamic models to investigate the performance of numerous BDCP scenarios with respect to such metrics as changes in the timing and magnitude of watershed run-off, reservoir storage, flows in the southern part of the Delta, and seasonal variations in the salinity gradient (the position of X2). This analysis appeared to address the hydrologic and hydrodynamic impacts of climate change, incorporating a sequence of linked models to propagate the effects throughout the system.
The panel did not see clear evidence of the use of these hydrologic and hydrodynamic effects to assess the corresponding impacts on ecological processes in the BDCP plan area. According to the DWR 2010 report, the operational simulations of the BDCP using DWR’s CALSIM II model have not been completed. Such an analysis is extremely important for investigating the feasibility of meeting future demands associated with the environmental, agricultural, and urban subsystems connected to the greater Bay Delta system. The panel could not find a clear discussion of the extent to which such demands may or may not be met under future climate change scenarios. In addition, there were no quantitative estimates of trade-offs between the co-equal goals of the plan under climate change scenarios, which is discussed below.
Incorporation of the following key elements would strengthen the BDCP’s treatment of climate change: (1) Provide a detailed documentation of the approach, analysis, and conclusions, with emphasis on uncertainties and their implications. The lack of discussion in the material provided to the panel of the plan’s approach to climate change makes it difficult to more definitively evaluate the scientific basis for climate change projections. (2) Continue efforts to select models with better skills, including models with the ability to reproduce ocean-atmosphere teleconnections, including regime shifts, in the California region (Brekke, 2008, 2009); (3) Quantify the impacts of warming, changes in watershed hydrology and sea level rise on the ecology of the Delta system though the use of ecological models (e.g., CASCaDE, 2010) and quantify the effects on the plan’s co-equal goals; and (4) clearly address the role of climate change in the adaptive management strategy. Considering the length of the planning horizon and the importance of climate change to the plan’s success, the panel concludes that the BDCP should include a separate chapter on this subject. In view of the importance of the climate change implications in the planning and
implementation of the BDCP, the panel recommends that this work be reviewed in detail by an independent expert panel assembled by the Delta Science Program or the Interagency Ecological Program.
A FRAMEWORK FOR LINKING DRIVERS AND EFFECTS
The comprehensive conceptual framework developed by the Interagency Ecological Program related to the drivers of pelagic organism decline in the Delta is an important example of supporting science (Mueller-Solger, 2010). This framework identifies and links, in the context of both ecosystem structure and functioning, the key stressors that help to explain the decline of pelagic organisms. The “drivers of change” (Figure 5) are quantifiable, “suitable for model evaluation” and directly linked to hydrologic, biogeochemical and biotic changes that accompany diversion of freshwater from the Delta and parallel increases in nutrient and other pollutants resulting from upstream anthropogenic activities. This is an example of how the individual components could be functionally and conceptually linked and of how climate-change modeling should be integrated into other aspects of the BDCP, including regime shifts.
FIGURE 5. Conceptual framework, providing example of supporting science for linking drivers of ecological change to fish community responses. This figure could be a starting point for establishing and rationalizing these linkages. SOURCE: Reprinted, with permission, from Interagency Ecological Program (2010) as modified from Sommer et al. (2007). Available online at: http://www.water.ca.gov/iep/docs/FinalPOD2010Workplan12610.pdf.
The types of stressors identified are integrative, reflecting co-occurring physical, chemical, and biotic changes. They also apply to multiple structural (food web structure, biodiversity) and functional (food transfer changes, biogeochemical cycling) changes taking place in the Delta. The framework and associated detail are both comprehensive and useful in terms of linking these drivers to changes taking place at multiple levels of the food web. This type of conceptual approach will also be useful for examining other drivers and impacts of ecological change, including observed changes in fish community structure and production; specifically, how these changes are affected and influenced by changes in physico-chemical factors (e.g., salinity, temperature, turbidity, nutrients/contaminants) and at lower trophic levels (phytoplankton, invertebrate grazers, and prey).
Such a conceptual framework is a necessary precursor to the more holistic integrated analyses for which this panel has identified a need. It may well be impossible to develop a single, integrated model that simultaneously addresses all sources of uncertainty. However, the panel identifies the need for clearer connections among the currently disparate analyses as part of a more synthetic BDCP.
SIGNIFICANT ENVIRONMENTAL FACTORS AFFECTING LISTED SPECIES
Much of the analysis of factors affecting the decline of smelt and salmonids in the Delta has focused on water operations, in particular, the pumping of water at the south end of the delta for export to other regions. This is in part because the pumping can be shown to kill some fish and in part because proposed changes in water operations were the focus of biological assessments and biological opinions developed by NOAA and USFWS (NRC, 2010b). However, many scientists and others in the region have recognized that other significant environmental factors (“other stressors”) have potentially large effects on the listed fishes (e.g., NRC, 2010b). Recent studies have suggested that some of these other factors might be of critical importance to fish (e.g., Baxter et al., 2010; Baxter, 2010; Glibert, 2010). In addition, there remain considerable uncertainties regarding the degree to which different aspects of flow management in the Delta, especially X2 management, affect the survival of the listed fishes (e.g., NRC, 2010b). Indeed, the significance and appropriate criteria for future environmental flow optimization have yet to be established, and are uncertain at best.
The panel supports the concept of a quantitative evaluation of the significance of stressors, ideally using life-cycle models, as part of the BDCP, but such a quantitative evaluation is not part of the draft of the BDCP. The panel concludes that in addition to being incomplete, the absence of a data-based, quantitative assessment and analysis of stressors, ideally using life-cycle models, that supports the effects analysis and adaptive management, is a significant scientific
flaw in the current version of the BDCP. A sound, data-supported, quantitative analysis of stressors should be one part of the planning process and should provide the foundation for the effects analysis, adaptive management, and ultimately the choice of conservation measures.
The panel finds the BDCP to be a long list of ecosystem management tactics or incomplete scientific efforts with no clear over-arching strategy to integrate the science, or implement the plan. Furthermore, the BDCP does not tie proposed actions together, in terms of addressing the co-equal goals in a unified way or in terms of ecosystem restoration. On the ecosystem side alone, the plan lists more than 100 restoration actions but provides no guidance on which actions are most important, which actions are more or less feasible, which species are more or less susceptible to extinction, which restoration efforts are most difficult, and which actions might be most easily and immediately addressed. In other words, there is a list but not a synthesized plan for the restoration activities. A systematic and comprehensive plan needs a clearly stated strategic view of what each major component of the plan is trying to accomplish, how it is going to do it, and why it is justified. Also, a systematic and comprehensive plan would show how the co-equal goals are coordinated and integrated into a single resource plan.
THE RELATIONSHIP OF THE BDCP TO OTHER SCIENTIFIC EFFORTS
A cohesive conservation plan should provide a clear picture of how the different efforts in the Delta fit together. Indeed, such a synthesis could be valuable not only to the BDCP but also to other conservation efforts in the region. As noted above, the BDCP does not provide adequate perspective on how it fits into, for example, the broader Delta Plan, or on how documents such as the Delta Risk Management Strategy fit into the BDCP. Also, aspects of the BDCP fundamental to understanding how and what science was applied are not yet developed. The inadequacies of ingredients such as the effects analysis, or the details of adaptive management or monitoring, lead the panel to ask, how will these tools be employed to assure effective implementation of the BDCP? How specifically will they be tied to the proposals for conservation and infrastructure change? Evidence of a coordinated conservation and water management strategy is the first step in establishing public trust that this is a scientifically credible effort.
Clarification of the volume of water to be diverted or mention of how it will be diverted is crucial to a scientific analysis. Moreover, it is unclear how the upper capacity limit of the isolated conveyance structure of 15,000 cfs (draft
BDCP Chapter 4.2.2.1.1 and Table 4-1) was established. The BDCP cannot be properly evaluated if it does not clearly specify the volume of water deliveries whose negative impacts are to be mitigated. The draft BDCP suggests that the water requirements are based on the amount of acreage and crops that contractors have grown, or on the maximum deliveries specified by the SWP contracts―up to 4.173 MAF/year by 2021 (draft BDCP, Chapters 4.3.1 and 5.1). There is no mention that quantities diverted may be constrained by various provisions of California water law, by possible changes in the extent of irrigated agriculture south of the Delta, and by potential changes in cropping patterns fueled by globalizing forces of supply and demand for food. The draft BDCP also fails to identify and integrate demand management actions with other proposed mitigation actions. A conservation plan should address issues of water use efficiency and should account for future trends in other variables that drive the demand for agricultural and urban water supplies. These issues are directly pertinent to the establishment of a water use strategy and they bear importantly on the costs of restoration actions intended to minimize adverse ecological effects. The BDCP’s lack of attention to these issues constitutes a significant omission, given the intensifying scarcity of water in California.
In short, synthesis at all levels is a key ingredient in converting a document into a plan. The lack of synthesis constitutes a systemic problem in the draft BDCP. The panel recognizes that the challenge of linking tactics and strategy with a problem this complex is great, but no plan is either complete or likely to point the way toward success without meeting that challenge.
