Sea Level Rise and Policy Change

Policy Studies Journal, Vol. 19,No. 2, Spring 1991 183-92)

Sea Level Rise and Policy Change: Land Use Management in the Sacramento-San Joaquinand Mississippi River Deltas Mark Meo The threat of global climate change caused by fossil fuel use and industrial activities is both unique and ubiquitous. Characterizedby uncertainty, irreversibility, and pervasiveness, an atmospheric warming of several degrees over the next century presents a substantial public policy challenge to craft effective and timely responses to an array of potential environmentalimpacts, of which one of the most serious is accelerated sea level rise (National Research Council, 1983; Schneider, 1989). Yet how well society can cope with changing climate and a rising Ocean is unclear. No historical precedent of a world undergoing change as rapidly or as dramatically exists, let alone one which can provide some reference for policy analysis or planning (Schelling, 1983; Lave, 1988). Societal responses to an unparalleled rise in sea level of up to a meter in the next century may take a variety of forms. Depending upon the timing and speed with which the Ocean rises, affected coastal communities may opt to defend their shoreline with structural and nonstructural measures or relocate landward at a pace that enables socioeconomic activities sufficient time to adapt to rising waters (National Research Council, 1987). Other less developed or less affluent regions may have to be abandoned. Developing acceptable policies for mitigating the risks associatedwith sea level rise requires crediblepredictions, an assessment of the specific climate change impacts likely to accrue,and a knowledge of actions that could be taken to reduce or minimize potential impacts. In support of such efforts, information about the way in which sea level rise impacts affect, and in turn are affected by, social institutionscan help gauge the feasibility of individual strategies.

Sea level Rise and its Attendant Effects Although a variety of geophysical factors can influence the level of the sea at any given place (e.g. glacio-isostaticrebound, tectonic uplift, subsidence), global warming is expected to alter sea level primarily by glacial melting and the expansion of surface waters. Due to uncertainty about the magnitude of future warming, however, the eventual increase in sea level is expected to vary between .5 m to 1.5 m over the next century with a mean rise of about .67 m (Oerlemans, 1989). This increase is striking in comparison to the 12 to 15 cm rise experienced in the last century (Hekstra, 1989). A more severe warming could increase sea level above 5 m, but this is believed likely only if the West Antarctic Ice Sheet melts and slips into the sea.

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Coastal encroachment by the sea is likely to induce a variety of environmental impacts. Low-lyingunprotected coastal regions are especially vulnerable (Bardach, 1989; Vellinga & Leatherman, 1989). Inundation of low-relief areas would lead to loss or retreat of coastal landforms including wetlands and other features such as coral reefs. Coastal erosion would also increaseconsiderablyand subject developed areas to greater storm damage and flooding. The Atlantic and Gulf coast regions would be particularly hard hit due to the loss or landward regression of coastal barriers, beaches, and wetland habitats. Upstream movement of saline water would threaten coastal aquifersand invadeestuarineenvironments. With the penetration of marine waters, increased river discharge would be necessary to protect vulnerable wildlife nursery habitat and drinking water supplies. The combined effect of related climate changes could exacerbate the impact of sea level rise and further imperil coastal regions. With atmospheric warming, the frequency and intensity of destructivestorms such as hurricanes and monsoons could increase markedly and contribute to higher storm surge, coastal barrier overwash, and flooding (Bardach, 1989; Emmanuel, 1987). In addition, should precipitation and seasonal temperature regimes change, major drainage basins may suffer effects of more frequent droughts or altered or reduced water budgets that could curtail downstream flow (Jacoby, 1990; Williams, 1989). As a result, increased occurrence of acute and long term risks to society and vulnerable ecosystems would necessitate effective anticipatory or adaptive actions. The cost to society to mitigate or lessen the impact of accelerated sea level rise is likely to be high. A recent EPA study of the U.S. coast found that adaptive measures such as elevating houses and roadways against a 1-m sea level rise by 2100 could cost between $50 and $75 billion. More costly mitigation measures such as bulkhead construction and sand pumping could add up to $100 billion (Smith & Tirpak, 1988). Estimates made in other parts of the developed world are comparable. In RijkswaterstaatNetherlands, the cost of new defense measures will be about twice the current cost of coastal defense maintenance. Strengtheningdikes, dunes, beaches, and shore faces for a 1-m sea level rise over the next century will cost about $3 billion. In Rotterdam, the cost of inland adaptations, revised operations, and modifications to harbors, locks, and bridges could total $5 to $6 billion over the next 50 years (Hekstra, 1989). For less developed countries where expensive technical solutions are not feasible (e.g. Bangladesh, Maldive Islands) the losses to sea level rise could be catastrophic. Because of the uncertain nature of climate change, studies of land use management in low relief coastal river deltas can aid understanding of how responsesto accelerated sea level rise might evolve. As depositionalenvironments produced by the interaction of riverine and marine influences, estuarine deltas are inherently dynamic and thus responsiveto changes in water and sedimentsupply, salinity intrusion, and sea level rise (Wright, 1978). In the Sacramento-San Joaquin and Mississippi River deltas, purposive reconfiguration of the land resource over several decades, designed for social benefits from navigation, flood

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control, agricultural production, or oil and gas extraction, has led to chronic subsidence and increased risk of inundation by levee failure or accelerated land loss to the sea. Although land subsidence is not geophysically equivalent to climateinduced sea level rise, the net result experiencedby society-encroachment by the sea-is the same. Moreover,the management history associated with subsidence and erosion problems also illustratesthe influenceof othernegative environmental effects and the policy issues that compete for limited public resources. Though each delta’s management history may lack congruence with projected sea level rise scenarios in a physical sense, they can serve a role as analogues through the elucidation of constraintsor incentives by which adaptiveclimatechange policies may be shaped.

Sacramento-San Joaquin Delta The inland delta which lies at the confluence of the Sacramento and San Joaquin Rivers in California’s Central Valley covers approximately 1,100 square miles and is comprised of over 60 individual islands. Approximately two-thirds of the Delta is in lowlands which lie below the five-foot mean-sea level contour. Since global warming could influence California’shydrologic regime as well as elevatesealevel, theDeltacouldsuffer from thecombinedeffectsof marine water intrusion and diminished downstream flow (Gleick, 1988). Williams (1988) estimates that a 1 meter rise in sea level could easily inundate the entire Delta and triple the areal extent of San Francisco Bay. Land use in the Delta, initially driven by an imperative to reclaim wetlands for agriculture, soon became influenced by the overlapping tasks of serving the water quality and supply needs of multiple local and nonlocal interests while beset by risks of chronic levee failure and continued subsidence. As understanding of the wider societal implications of subsidence grew, policies were adopted that sought to protect the Delta by structuring cooperation among resourceplanning and management institutions. Risks from subsidence,however, still remain acute and costly to resolve. Extensive reclamation activities commenced in the Delta shortly after 1850 when marshy land was diked and drained for farming. Active reclamation of the Delta islands continued until 1930 when a total of 4 16,000acres of islands and tracts had been leveed (Basye, 1981). The initial wave of levee construction lasted up to 1879. After this time enlargement and modificationswere undertaken due to recurring levee failures caused by the fundamental instability of peat used as building material and for basement support (Thompson, 1982). Salinity in the Delta is determined by the balance between fresh water flowing in from the east and north, mostly down the SacramentoRiver, and ocean tides pushing in from San Francisco Bay through the Carquinez Strait. As a result of upstream use of river waters and occasional droughts, salinity incursions of a half century ago could move upstream to Stockton and almost as far as Sacramento. Concern by Delta farmers about poor water quality for irrigation, 85

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however, was put to rest with the developmentof the Central Valley Project (CVP) which, although begun by the state, was later assumed by the federal government. The first export of Delta water took place in 1940 when the CVP began operating the Contra Costa Canal. With the closure of the Shasta Dam in 1944, SacramentoValley surface water became availablefor transfer to the San Joaquin Valley which began in 1950with the completion of the Tracy pumping plant. To facilitate cross-Delta water flow and minimize saline intrusion, the Delta crosschannel was cut in the SacramentoRiver. The net result of the CVP transfer was to transform the Delta from a fresh water reservoir that could accommodate seasonal water demands into more of a river with flow being directed southward to the pumps. Use of the Delta for water transfer was further committed with the State Water Project (SWP) which began operation in 1967. Additional channel improvements were made to convey the combined CVP and SWP water exports which, by 1980, accounted for over 25% of historic Delta flow to San Francisco Bay (Nichols, Cloern, Luoma, & Peterson, 1986). Use of reclaimed Delta wetlands for agriculture led to chronic subsidence brought about by oxidation of peat, shrinkage,erosion by wind, compaction by farm equipment,anaerobicdecomposition,and burning (Department of Water Resources, 1986). Delta islandsrich in peat haveexperiencedthe most subsidence with the centers of some islands up to 25 ft below sea level. Coupled with unstable levees, cumulative subsidence has exacerbated levee failure and flooding. Most of the islands and tracts have been inundated at least once since reclamation,and some have been flooded on several occasions. Since the turn of the century there have been over 125 island inundations which have resulted in over 800 square miles of flooded area (Department of Water Resources, 1987a). Plans to offset chronic levee failure and island subsidence have been central to SWPand CVP water transfers and goals for protecting the environmental quality of the downstream Suisun Marsh and San Francisco Bay. Over the years, three basic concepts for managing the Delta have been discussed, including: a separate channel to cany water around the eastern periphery of the Delta, a single barrier at the west end of the Delta that restricts salt water, and modification of the interior Delta channels to improve their carrying capacity and retard saline intrusion. The peripheral canal option, first proposed in 1930, was endorsed by the state and federal government in 1961, and became subject to public referendum in 1982 when it was defeated soundly despite the active support of state agencies and some environmentaliststhat felt that cessation of Delta cross flows would be environmentallybeneficial. The second option, which was promoted actively but unsuccessfully from 1940 to 1965 as the Reber Plan, would have physically separated the north and south arms of San Francisco Bay to provide abundantfresh water for transfer to the San Joaquin Valley (Hedgpeth, 1979). In the absence of a public consensus for the first two options, federal, state, and local Della land use management has continued to evolve around the third. Growing recognition of the critical interdependence between Delta levees and water quality and quantity in the last three decades, has motivated

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Symposium on Global Climate Change and Public Policy: Meo closer coordination among federal, state, and local interests to safeguard multiple water and land use objectives. With the reduction of Delta outflows to San Francisco Bay by almost 60% of historic levels. attention has become sharply focused on the environmental consequences of Delta land subsidence and water diversions and the alternative courses of action which could be taken to mitigate them (Davoren, 1982). State concern about maintaining salinity control and water quality in the Delta led to the passage of the Delta Protection Act in 1959. The Delta Water Agency, created in 1968 to further these goals, was divided into three separate agencies by 1973 in order to reach agreements more quickly (Basye, 1981). That same year, the state passed the Way Bill which provided state financial assistance to local districts for improving levees for flood protection. In 1976, a conceptual plan to improve Delta levees was adopted by the state. Bay-Delta water quality standards for the SWP and CVP were issued by the StateWater Resources Control Board (SWRCB) in 1971 and clarified by SWRCB Decision 1485 in 1978. This broad sweeping decision, later upheld in 1986, helped to catalyze bilateral efforts to achieve better protection of the Suisun Marsh and led to a costsharing agreement between the federal Bureau of Reclamation and the state Departments of Water Resources and Fish and Game in 1987 (Department of Water Resources, 1987b). A follow up review by the SWRCB of Bay and Delta water quality control plans and SWP and CVP water uses is scheduled for completionin 1990. In addition, the State Departmentof Water Resourcesand the Bureau signed a Coordinated Operation Agreement in 1986 that facilitates water resource management between the SWP and the CVP. As costs for levee repair, pumping, and drainage have risen, they have incurred higher costs for Delta agriculture and flood control. About $4 billion in state and federal funds is necessary to protect the Delta against current sea level. Alternative land uses that would reduce the risk of levee failure and offset subsidence have been examined in extensive detail by both the state and federal government. Some of the options examined include clustering islands into polders, strategically inundating individual islands, using the islands for solid waste disposal, and developing aquaculture and fishery enhancement (Abell, 1986; Riebsame &Jacobs, 1989).

The Mississippi River Delta In the next century, accelerated sea level rise could inundate much of southern Louisiana and almost encircle New Orleans. Originally located on a natural levee of the Mississippi River, much of the Crescent City presently lies below sea level and is protected by a battery of pumps and flood control levees. If temperatures increase the Gulf of Mexico could travel up to 33 km inland and heighten the risk of hurricane devastation to New Orleans. For variousreasons the state of Louisiana is currently engaged in an active campaign to fortify its coastal zone and even create new wetlands where practicable.

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Over the past 7,000 years, the Mississippi River has created seven deltas by a process of delta switching in which the river abandoned its main channel every 1,000 years or so in favor of a shorter route to the Gulf of Mexico (Frazier, 1967). Once abandoned, delta lobes eroded while new sedimentary deposition and wetland growth resulted from active river discharge. In this manner, the expansive and biologically rich coastal wetlands of south Louisiana were created and sustained. The productivity of this ecosystem which accounts for 28% of the Nation’s wetlands is quite high. Louisiana fisheries, the largest tonnage in the U.S., are valued at over $200 million dockside annually (Templet & MeyerArendt, 1988). Except for the young and rapidly accreting Atchafalaya River delta emerging west of the Mississippi, navigation and flood control structures built along the river in the last 60 years by the U.S. Army Corps of Engineers have effectively precluded continued supply of nutrient-rich sediments to interdistributary marshes. Devoid of sediment and nutrients, the wetlands have incurred an accretion deficit and experienced extensive subsidence (Day, 1987). Compounding this process, oil and gas canals excavated from the 1930s onward have bequeathed to the deltaic plain a growing network of crisscrossingchannels that has enhanced saline intrusion, erosion, and consequent marsh deterioration. Collectively, these activities have contributed to a decline in wildlife habitat and an escalating trend in coastal land loss over time. Annual losses, which were estimatedatalittleunder7 squaremilesin 1913,hadincreased toalmost 16square miles by 1946. Between 1967 and 1980 annual land loss accelerated from 28 square miles to 40. At present, coastal land is being lost to the sea in excess of 50 square miles each year (Turner, 1987). Two local governments affected most directly by this problem have undertaken a number of preventive and remedial actions to inhibit invasion by Gulf waters. With land resources expected to erode in less than 50 years, Plaquemines Parish, which straddles the Mississippi River just below New Orleans, has installed several freshwater siphons to retard saline intrusion and is actively promoting strategiclevee breaks along the river toredirectriver sediments for new wetland creation. The parish also has sought federal approval to fortify the Chandeleur Islands barrier islands with sand. Terrebonne Parish, which had lost 42% of its barrier island acreage by 1984, has developed a comprehensive plan to offset land loss. Its four program goals include the development of a comprehensive data base, public education, wetlands preservation, and barrier island preservation. While public education has been directed to younger age groups, public support has also underwritten barrier island stabilization. Over $1.1 million in local funds has been allocated to the stabilization of eastern Isles Derniers. Ultimately, when resources become available the parish would like to construct a protective ring dike that would provide tidal exchange as well as wetland protection. Louisiana state government began to address coastal management problems in a coherent manner in 1971 with the establishment of an Advisory Commission on Coastal and Marine Resources. With the assistance of coastal

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Symposium on Global Climaie Change and Public Policy: Me0 parishes, public officials, and technical experts, a policy report was released in 1973which helped guide the state through a politically turbulent and divisive fiveyear effort to develop a state program to regulate coastal activities (Houck, 1983). Continued wetland losses, however, coupled with recommendations from scientific studies and concern about a possible boundary change motivated the creation of a Coastal Protection Trust Fund in 1981 with an endowment of $35 million for specific projects. Pursuant to state task force reports released in 1982and 1984, a Coastal Protection Master Plan was developed that identified a variety of actions to be carried out in two phases including a broad based effort to restore barrier islands and eroded shorelines,promote coastal vegetation, and develop and implement a wetlands protection program. The costs for coastal protection are substantial; stabilization of barrier islands, for example, is estimated to be $131 million over five years. In 1988, Governor Roemer released a multiagency review of coastal protection strategies that set goals and strategies as well as priorities for immediate, short-term,and long-term actions. Specificpolicy goals were: to elevate the status of wetlands by specifying protection and remediation criteria that are consistent for all development actions (includingcanal dredging); to utilize more effectively the land building capacitiesof the Atchafalaya and Mississippi Rivers; to promote state leadership through the development of a physical, multi-use, master plan for coastal stabilizationand restoration;and, to foster local, state, and federal coordination (Coastal Restoration Technical Committee, 1988). To this end, a model land use plan has been developed for an interdistributary basin (Barataria Basin) that addresses wetland loss, hydrologic isolation, water quality, cultural resources, and economic development issues (Hartman & Cahoon, 1989). With continued lobbying on behalf of wetlands and growth in public awareness, efforts to bolster coastal protection have remained high on the state political agenda. In order to provide a more stable source of support and funding for coastal protection projects, the state legislature voted in 1989 to establish a Wetlands Conservation and Restoration Trust Fund and a cabinet level position in the Governor’s office to expedite all coastal protection projects and oversee consistency provisions. In October, 1989,71% of the state’s voters approved a constitutional amendment that will allocate between $5 million and $40 million a year from Louisiana’s oil and gas revenues to the trust fund beginning July, 1990. Although the federal government has played a prominent role in Louisiana through its activities on the Mississippi River, it was not until 1967 that the Corps began environmental studies of the deltaic plain. Despite its obvious land building potential, the Corps began to examinethe feasibility of Mississippi River diversions in 1980, principally to restrict saline intrusion. Controlled diversions located at Caernarvon and Davis Pond, for example, would release fresh water to foster oyster production but not necessarily marsh creation. That activity would be performed through planned levee breaks in the Birdfoot delta region that would release both sediment and water. Completion of the Caernarvon diversion, which

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has been endorsed through state and federal cost sharingagreements,is scheduled for completion in the early 1990s. Meanwhile, the Corps has initiated a variety of barrier island stabilizationand wetland protection projects and has cooperated with the state and local governments in their efforts to repel the sea.

Discussion The account of changes in river delta land use activities presented here provides two different perspectives on societal adaptation to long-term environmental changes beset by acute and chronic risks. In California, while the risk of catastrophic island inundation is perceived as manageable, current plans may be overwhelmed by a modest rise in sea level. A 1 -ft rise, for example, could cost $334 million to reclaim all flooded islands, and $298 million to reclaim only the 13 most valuable ones (Logan, 1990). Continued levee failure, the cost of which has been increasing for reclaiming flooded land, is currently receiving more attention and resources from the state. In 1989,California allocated $1 14 million for levee repairs. If this proves inadequate,strategic shifts in land use away from agriculture to a more compatible and less costly activity to maintain such as aquaculture could occur. Should these adjustments fare poorly given various climate change contingencies, the peripheral canal option can be considered anew. In contrast, Louisiana is actively engaged in developing a workable institutional structure and management strategy that will support its efforts to protect the coast. As the pace of land loss has risen, the range of alternativeactions and policy spheres has broadened, Options that utilize both structural and nonstructural remedies have been identified with some action taken, but not necessarily with a firm basis in scientific understanding,economic impact,or state capabilities. For Louisiana, a loss minimization strategy necessitates close coordination between federal and state programs as well as a workable land use plan for substate governments. These cases illustrate some of the factors likely to affect societal adaptation to global sea level rise. Importantpolicy issues drawn from these cases highlight the role of research and information transfer in the design and implementation of coastalprotection actions,how public awarenessandvaluesdetermine the acceptability of technical alternatives, and the dilemma that environmental resources such as coastal wetlands can present society as it sets climate change response priorities. In both cases, the impulse for development forsook environmental complexity and incurred damages which accrued over time. Without an adequate basis in knowledge by which fragile coastal environments could be valued and managed, the risk of long term economic losses increased as did societal vulnerability in general. In view of the multiple impacts associated with climate change, both cases demonstrate clearly the limited ability of each state and the federal government to respond effectively to ill-defined, cumulative, or synergistic effects. As complex social and natural systems, coastal regions and fragile

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systems, such as river deltas, will necessitate better integration of potential climate change effects with an assessment of remedial or protective actions. Sea level rise impact studies should recognize the site specificnature of potential longterm effects and the influence of other climate change impacts on developmentor protection plans. As projectionsof global warming effectsbecome more accurate, resource analysts should place greater emphasison integrated approachesthat can define the values, resources, and future risks that are central to sustainable development. Unless more systematic and inclusive approachesto environmental planning and management are adopted, current strategies may prove to be too slow, too costly, too cumbersome, and too flawed to minimize future social and environmental impacts.

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Policy Studies Journal, 19:2 Houck. 0. A. (1983). Land loss in coastal Louisiana: Causes. consequences, and remedies. Tulane Low Review, 58, 3-168. Jacoby. H. D. (1990). Water quality. In P. Waggoner (Ed.), Climate change and U.S. water resources. New York: John Wiley & Sons. Lave, L. B. (1988). The greenhouse effect: What government actions are needed? Journal of Policy Anulysb and Manugement, 7(3). 460-470. Logan, S . H. (1990). Global warming and the Sacramento-San Joaquin Delta. California Agriculfure,44(3), 16-18. National Research Council. (1983). Changing climate. Washington, DC:National Academy Press. National Research Council. (1987). Responding 10 changes in sea level: Engineering implications. Washington, DC: National Academy Press. Nichols, F. H., Cloem, J. E., Luoma,S. N.. & Peterson D. H. (1986). The modification of anestuary. Science, 231,561-573. Oerlemans, J. (1989). A projection of future sea level. Climatic Change, 15, 151-174. Riebsame. W. E.. & Jacobs, J. W. (1989). Climate change and water resources in the SacramentoSan Joaquin region of California: Policy adjustment options. In J. B. Smith & D. A. Tirpak. (Eds.), The potenfial effects of global climate change on the United States. Washington, D C U.S. Environmental Protection Agency. Schelling, T. C. (1983). Climatic change: Implications for welfare and policy. In National Research Council (Ed.), Chunging c f k i e . Washington, DC: National Academy Press. Schneider. S. H. (1989). The greenhouse effect: Science and policy. Science 243, 771-781. Smith, J. B.. & Tirpak, D. A. (Eds.). (1989). Thepofentialeffects ofglobal climate change on the Unifed States. Washington, DC: U.S. Environmental Protection Agency. Templet. P. H., & Meyer-Arendt, K. J. (1988). Louisiana wetland loss: A regional water management approach to the problem. Environmental Management, 12(2), 181-192. Thompson, J. (1982). Discovering and rediscovering the fragility of levees and land in the Sacramento-San Joaquin Delta. 1870-1879 and today. (Research Paper) Sacramento, CA: Department of Water Resources. Turner, R. E. (1987). Relationship between canal and levee density and coastal land loss in Louisiana. Biological Report, 85( 14). Washington, DC: U.S. Fish and Wildlife Setvice. Vellinga, P. & Leatherman, S. (1989). Sea level rise, consequences and policies. Climatic Change, I S , 175-189.

Williams. P. (1988). The Impacts of climafe change on the salinity of San Francisco Bay, San Francisco, CA: Philip Williams & Associates. Williams. P. (1989). Adapting water resources management to global climate change. Climatic Change, 15.83-93. Wright, L. D. (1978). River deltas. In R. A. Davis (Ed.). Coastal sedimentary environments (pp. 5-68). New York, NY: Springer-Verlag.

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