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Products: Water Resources

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Optimal and Sustainable Groundwater Extraction

With the specter of climate change, groundwater scarcity looms as an increasingly critical issue worldwide. Minimizing the adverse effects of scarcity requires optimal as well as sustainable patterns of groundwater management. We review the many sustainable paths for groundwater extraction from a coastal aquifer and show how to find the particular sustainable path that is optimal. In some cases the optimal path converges to the maximum sustainable yield. For sufficiently convex extraction costs, the extraction path converges to an internal steady state above the level of maximum sustainable yield. We describe the challenges facing groundwater managers faced with multiple aquifers, the prospect of using recycled water, and the interdependence with watershed management. The integrated water management thus described results in less water scarcity and higher total welfare gains from groundwater use. The framework also can be applied to climate- change specifications about the frequency, duration, and intensity of precipitation by comparing before and after optimal management. For the case of South Oahu in Hawaii, the prospect of climate change increases the gains of integrated groundwater management.

working paper


Optimal Management of a Hawaiian Coastal Aquifer with Near-Shore Marine Ecological Interactions

We optimize groundwater management in the presence of marine consequences of submarine groundwater discharge (SGD). Concern for marine biota increases the optimal steady-state head level of the aquifer. The model is discussed in general terms for any coastal groundwater resource where SGD has a positive impact on valuable near-shore resources. Our application focuses of the Kona Coast of Hawai’i, where SGD is being actively studied and where both near-shore ecology and groundwater resources are serious socio-political issues. To incorporate the consequences of water extraction on nearshore resources, we impose a safe minimum standard for the quantity of SGD. Efficient pumping rates fluctuate according to various growth requirements on the keystone marine algae and different assumptions regarding recharge rates. Desalination is required under average recharge conditions and a strict minimum standard, and under low recharge conditions regardless of minimum standards of growth.

working paper


An Economic Assessment of Biological Control for Miconia calvescens in Hawaii

Biocontrol, the introduction of organisms to control an unwanted species, has been cited as a powerful method to manage the invasive species Miconia calvescens in Hawaii. In addition to ecological advantages, biocontrol is often regarded as less costly than traditional methods despite the large initial investment. Currently, miconia in Hawaii is treated through aerial and manual operations, which cost over $1 million annually. Biocontrol for miconia in Hawaii began in 1997 and the search for more agents continues today. Although biocontrol for miconia has already begun, prior to this study no assessment of its economic justifiability had been done. This research evaluates the present value of net benefits of miconia biocontrol in Hawaii. Cost data were gathered from scientists in charge of biocontrol programs. Benefits were defined as the cost-savings of current control methods. Two different biocontrol programs were modeled: control achieved by a single agent, and control achieved by a suite of agents. In addition, different dispersal rates and efficacies of biocontrol and two release dates were modeled. Because most costs of biocontrol are incurred before the release of a successful agent and the benefits are only realized post-release, each scenario was evaluated over a 50-year time horizon. The results indicate a positive present value of net benefits in all scenarios, ranging from $12.8 million to $36.1 million. Thus, biocontrol for miconia in Hawaii appears to be economically justifiable. This research should enable scientists, economists and policy makers to make informed decisions about the optimal management of Miconia calvescens in Hawaii.

working paper


Spatial Economic Analysis of Early Detection and Rapid Response Strategies for an Invasive Species

Economic impacts from invasive species, conveyed as expected damages to assets from invasion and expected costs of successful prevention and/or removal, may vary significantly across spatially differentiated landscapes. We develop a spatial-dynamic model for optimal early detection and rapid response (EDRR) policies, commonly exploited in the management of potential invaders around the world, and apply it to the case of the Brown treesnake (Boiga irregularis) in Oahu, Hawaii. EDRR consists of search activities beyond the ports of entry, where search (and potentially removal) efforts are targeted toward areas where credible evidence suggests the presence of an invader. EDRR costs are a spatially dependent variable related to the ease or difficulty of searching an area, while damages are assumed to be a population dependent variable. A myopic strategy in which search only occurs when and where current expected net returns are positive is attractive to managers, and, we find, significantly lowers present value losses (by $270m over 30 years). We find further that in the tradeoff between search costs and damages avoided, early and aggressive measures that search some high priority areas beyond points of entry even when current costs of search exceed current damages can save the island more ($295m over 30 years). Extensive or non-targeted search is not advised however.

working paper


The Value of a Wave: An Analysis of the Mavericks Region Half Moon Bay, California

This study was commissioned by the Save the Waves Coalition to determine the value of the Mavericks surf area to the local community and beyond. 

working paper


Renewable resource management with stock externalities: Coastal aquifers and submarine groundwater discharge

This paper develops a hydrologic-ecologic-economic model of groundwater use. Particularly, we model coastal groundwater management and its effects on submarine groundwater discharge, nearshore marine water quality, and marine biota. We show that incorporating the external effects on nearshore resources increases the optimal sustainable steady-state head level. Numerical simulations are illustrated using data from the Kuki’o region on the island of Hawaii. Two different approaches for incorporating the nearshore resource are examined. Including algae’s market value in the objective function results in only slightly lower rates of extraction. When a minimum constraint is placed on the stock of the keystone species, however, greater conservation may be indicated. The constraint also results in non-monotonic paths of water extraction, head level, and water price in the optimal solution.

Published: Pongkijvorasin, S., Roumasset, J., Duarte, T. K., and Burnett, K., 2010. Renewable resource management with stock externalities: Coastal aquifers and submarine groundwater discharge. Resource and Energy Economics, 32 (3), 277-291.

 working paper version


Resource management for Sustainable Development of Island Economies

What is the role of resource management in sustaining competitiveness for island economies such as the Republic of the Philippines and Hawaii? We review the history of thought on sustainable resource management and sustainable development and then turn to the threats to sustainability from the resource curse and the parallel curse of paradise. We show how the resource curse undermines the pursuit of sustainability and describe innovations in governance that can transform the curse into a blessing.

working paper


Environmental Resources and Economic Growth

This chapter assesses the nature and degree of environmental degradation and resource depletion in China and their relationship to economic activity and envi- ronmental policies. We describe regulatory and other policies and consider their political economy determinants. Inasmuch as this objective can only be partially achieved, we hope to contribute to a research agenda for environmental and resource economics in China.

Book Chapter


The Economic Value of Watershed Conservation

Watershed conservation creates benefits within and beyond the management area of interest. Direct benefits are those realized in the watershed itself, such as improved water quality and quantity, and biodiversity protection. Additionally, the health of a watershed has profound implications on near-shore resources below its reaches, including beaches and coral reefs. This chapter reviews the major benefits of watershed conservation and discusses the economic value of these activities.

working paper


Economic lessons from control efforts for an invasive species: Miconia calvescens in Hawaii

Once established, invasive species can rapidly and irreversibly alter ecosystems and degrade the value of ecosystem services. Optimal control of an unwanted species solves for a trajectory of removals that minimizes the present value of removal costs and residual damages from the remaining population. The shrubby tree, Miconia calvescens, is used to illustrate dynamic policy options for a forest invader. Potential damages to Hawaii’s forest ecosystems are related to decreased aquifer recharge, biodiversity, and other ecosystem values. We find that population reduction is the optimal management policy for the islands of Oahu, Maui, and Hawaii. On the island of Kauai, where tree density is lower and search costs higher, optimal policy calls for deferring removal expenditures until the steady state population is reached.

Published: Burnett, K. M., Kaiser, B. A., and Roumasset, J. A., 2007.  Economic lessons from control efforts for an invasive species: Miconia calvescens in Hawaii. Journal of Forest Economics, 13, 151-167. 

Working Paper version


Economic impacts of non-indigenous species: Miconia and the Hawaiian economy

Imperfect scientific information regarding potential invasiveness, differences between private and public outcomes for individual decisions regarding planting, and inadequate prevention activity combine to impose costs through a change in native ecosystems susceptible to invasion by hardy, rapidly reproducing non-indigenous species. Concepts and tools from economic theory that may improve policy decisions are explored through the specific example of Miconia calvescens in Hawaii. Rapid expansion of Miconia calvescens, an ornamental tree introduced to several Pacific Islands over the last century, threatens local watersheds, endangered species, and recreational and aesthetic values in the Hawaiian and Society Islands. Potential welfare losses from the unchecked spread of Miconia in Hawaii are illustrated. Policy options investigated include accommodation of these losses, efforts at containment, or eradication. Estimates are determined through an optimal control model describing the potential expansion of the weed and its control costs and damages. Results suggest that cost-effective policies will vary with the level of invasion as well as the expected net benefits from control efforts.

working paper


Efficient Water Allocation with Win-Win Conservation Surcharges: The Case of the Ko‘olau Watershed

The one-demand Hotelling model fails to explain the observed specialization of non-renewable resources. We develop a model with multiple demands and resources to show that specialization of resources according to demand is driven by Ricardian comparative advantage while the order of resource use over time is determined by Ricardian absolute advantage. An abundant resource with absolute advantage in all demands must be initially employed in all demands. When each resource has an absolute advantage in some demand, no resource may be used exclusively. The two-by-two model is characterized. Resource and demand-specific taxes are shown to have significant substitution effects. 

working paper


Valuing Indirect Ecosystem Services: the Case of Tropical Watersheds

Mitigating the harmful effects of development projects and industries (negative environmentalism) is inadequate, especially in resource-dependent economies whose resources are at risk from other forces. While positive environmentalism includes conservation projects, the non-market benefits of such projects are difficult to evaluate. This paper provides and illustrates a method for evaluating the indirect, watershed benefits of a tropical forest, without resorting to survey methods. The conservation of trees prevents a reapportionment from groundwater recharge to runoff that would otherwise occur. The value of the water saved is then valued at the shadow prices obtained from an optimizing model. An illustration of the model shows that watershed conservation projects may have very high payoffs, even before assessing existence values and other forest amenities.

working paper


Control of Invasive Species: Lessons from Miconia in Hawai'i

 The threat of invasive species stems from their ability to rapidly and irreversibly change ecosystems and degrade the value of ecosystem services. Optimal control of a pre-established exotic pest minimizes the costs of population reduction plus the residual damages from the remaining pest population. The shrubby tree, Miconia calvescens, is used to illustrate dynamic policy options for a forest invader. Potential damages to Hawaii's forest ecosystems are related to decreased aquifer recharge, biodiversity, and other ecosystem values. We find that population reduction is the optimal management policy for the islands of Oahu, Maui, and Hawaii. On the island of Kauai, however, optimal policy calls for deferring control expenditures until the (larger) steady state population is reached.

working paper


On the Garden Path: an economic perspective on prevention and control policies for an invasive species

 

Published: Kaiser, B. A., 2006. On the Garden Path: an economic perspective on prevention and control policies for an invasive species.  Choices: The Magazine of Food, Farm, and Resource Issues. 21 (3), 139-142.


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