The Long-term Context of River Restoration: Social and Environmental

1. The Long-term Context of River Restoration: Social and Environmental Tom Dunne Spring 2010

2. Conceptual model of the California Bay-Delta Restoration Program

3. Conceptual model of the California Bay-Delta Restoration Progam

4. Historical socio-economic context of river restoration • >$1 billion/yr being spent in US • Plus ~$1-2 billion for Kissimmee R., Glen Canyon Dam, San Francisco Bay, and Missouri R. restoration. CALFED? • Context of recent national wealth and restoration ethic • Right-skewed distribution of projects and opportunities • A few ~ 10yr, >100 million/yr, 10s-100s km • Most < 1km long, Average cost/project $384,000; median cost per goal $45,000 • Skewed geographical distribution • 88% of projects in PNW, California, and Chesapeake Bay w/s • Natural resource opportunities (different) • National visibility • Regional wealth and interest • Also small dam removals ~50/yr (out of ~77,000 in the country) but potentially high payoff in terms of habitat if we get to large ones Bernhardt et al, Science (2005)

5. Scientists comment on the Proposed National Objectives, Principles and Standards for Water and Related Resources Implementation Studies required by Section 2031 of the Water Resources Development Act of 2007 (WRDA 2007). • The new OP&S provide a critical opportunity to ensure that the nation’s water projects meet clear standards of environmental sustainability even as they continue to advance the nation’s economic development • The National Objective must shift from a policy of no net loss of ecosystem function to one of improvement in ecosystem function. The operation of existing projects, such as federal dams, should be evaluated for opportunities to improve ecosystem health and function. • Project selection should not be driven solely by benefit-cost ratios, which discount non-market ecosystem services and will largely eliminate projects focused on restoring degraded ecosystems. Rather, projects should be selected based on their ability to meet national policy criteria and their overall cost-effectiveness. • All projects should be required to demonstrate their adaptive capacity. This includes substantial, sustained investments in scientific infrastructure and adaptive management.

6. Long-term trends in water availability for rivers • Other examples are • Climatic/hydrologic persistence • Secular reductions in runoff due to regional re-forestation • Climatic changes? 2000

7. Environmental Context In addition to the obvious, local, fast-reacting processes expected to affect a river restoration project (flow restoration, re-vegetation, sediment supply, etc. that we have covered) , be aware of subtle, slow, landscape-scale processes

8. Yakima River channel avulsion undermines new I-82 freeway, for which gravel had been mined from deep pits in the Yakima floodplain.Led to plan for stabilization of the river and development of a regional park, designed by Jones & Jones, Landscape Architects and River Planners, Seattle, WA

10. Aerial photo of southern Yakima River floodplain next to the city of Yakima, WA before development

11. Channel mobility map, Yakima R. Geologic map of Yakima R. valley

12. Puget Sound Lowland, WA:River management in a recently de-glaciated region near active volcanoes

14. Incision of White R gorge through 6,000 yr-old Osceola mudflow deposit

15. Continuing incision and aggradation along White R.Data from channel cross sections surveyed for flood routing calculations, 15 years apart Upstream Downstream

16. Evidence of continuing channel bed aggradation in lower river --- requiring continued channel dredging and diking to protect communities --- sediment accumulation lowers quality of salmon habitat from USGS current-meter records [9207 forms] of gauge height at low flow

17. Message: Subtle landscape-level processes operate at rates that are relevant for a restoration program Example provided by Prof. Jeff Mount, Geology Department, UC Davis, July 2005

18. Subsidence, Seismicity and Sea Level Rise: The Dynamic Future of the Delta* Jeffrey Mount Watershed Center UC Davis * The information in this talk is currently under review by the CalFed Independent Science Board

19. Old News Revisited as a Hypothesis • The Delta is a dynamic landscape undergoing significant change at multiple scales • Change will be considerable in the future due to continued subsidence and sea level rise • There is a high probability that abrupt change will take place in the next 50 years • There is no institutional capacity to respond to dynamic Delta landscapes

20. Delta Landscape Processes • Subsidence • Sea Level • Seismicity • Sedimentation • Climate Change • Hydrology • Land Use

21. Natural delta wetland construction;accumulation of peat keeps pace with rising sea level and levees Accumulation of largely organic debris from tule marsh plantss Silt and clay settle from suspension along edge of channels and build up a levee as sea level rises after Last Glacial Maximum

22. Reduction of marsh surface by oxidation of organic material after drainage and burning Need for artificial levee building

23. Nature, v 432, 2004

24. Blocking drainage to restore burned, drained land Nature, v 432, p. 144, 2004

26. Mount Calculated Two Indices of the Change • Anthropogenic accommodation space as a proxy for the subsidence • Levee hydrostatic force as a proxy for the potential for levee failure

27. Accommodation Space Index ASI = (As + Aa)/Aa Where: As = Anthropogenic Accommodation Space Aa = Subaqueous Accommodation Space b Levee Force Index LFI = Ft/F1900 Where: Fl = (hydrostatic pressure) x (depth x width) = Force/unit levee length Ft = Fl x Levee Length since Fl= (.5rgH)(H • b), then Ft is proportional to H2

28. Prediction of Past and Future of these Two Indices: Data Sources • Shuttle Radar Topography Mission (SRTM), Feb. 2000 • CDWR Island data, peat distribution and thickness • Deverel publications

29. Methods: Historic Change • Zonal statistics to estimate Aa in 2000 • Bathymetric data to estimate As • Estimated average annual accommodation space change for 1900-2000 • Calculated hydrostatic force on each levee segment based on island elevation relative to MSL

30. Methods: Simulations • Regressed 1920-1980 and post-1950 data (Deverel data) • Estimate decline in subsidence rates on peat soils (conservative) • Factored in IPCC sea level rise by 2050 (conservative) • Assume business-as-usual conditions, simulated stepwise lowering of islands until base of peat layer encountered

33. 2.5 Hydraulic Mining Eras worth of current space (Gilbert, 1917) • 1500 years to restore existing space with current sediment loads (Schoellhamer, USGS), but • Sea level rise alone creates almost twice the annual space that sediment is capable of filling • Average daily increase of more than 27,000 m3

36. Gradual Change: Tendencies and Trajectories • Potential for and consequence of island flooding • Backlog of $1B just to achieve PL-84 standards for current conditions • Single-island failures cost $50-100M • Unknown impacts on water supply, ecosystems J. Punia

37. Consequence of increasing accommodation space and increasing hydraulic forces on levees is to increase the probability of levee failure and “island” inundation Loss of rich agricultural land and housing

38. Consequence of increasing accommodation space and increasing hydraulic forces on levees is to increase the probability of levee failure and “island” inundation Instantaneous influx of saline water to waterways from which Southern California’s water supply is pumped, requiring shutdown of the supply

39. Abrupt Landscape Change • Potential for significant island flooding during major floods or seismic events of >100-year recurrence interval (.01 exceedance probability) • Widespread flooding of Delta islands will be a multi-year, multi-billion dollar disruption • Abrupt change likely to result in permanent changes in Delta hydrology, water quality and ecosystems: a “new” Delta Torres et al. (2000)

40. J. Punia

41. Abrupt Change in 50 Years: Remote or Real? Some Probabilities • 100-year earthquake = .40 • 100-year flood event = .40 • 100-year earthquake AND flood = .16 • 100-year earthquake OR flood = .64 There is a 2-in-3 probability that abrupt change will occur in the Delta in the next 50 years Torres et al. (2000)

42. Conclusions • Gradual change a certainty; abrupt change highly likely • Estimates here are conservative and do not reflect cascade effects or embedded thresholds • Left out impacts of regional climate change, including higher temps and larger floods J. Punia

43. Conclusions (July 2005) • Increasing levee failures, with significant but unknown impact • No economically feasible method to restore elevations • CALFED and other management/restoration program planning remains predicated on a fixed, rather than dynamic landscape • State scrambling madly since Hurricane Katrina, August 2005 J. Punia J. Punia

44. Message • While taking advantage of the socio-economic opportunity for river restoration, don’t ignore “predictable surprises” arising from subtle, long-term landscape changes • They are bigger than you are!