Water Resources and Economics最新文献

What is the economic value of storing water for future droughts, and what are the consequences of this valuation for water management? One way to answer this question is to ask: ‘what is the valuation, which if used, would maximize a region's economic use of water?’ This prescriptive valuation can be done by linking classical hydro-economic models to global search methods. Another way to answer this question is to ask: ‘what do historical water management operations reveal about water's economic value?’ Indeed, past reservoir uses reveal the empirical inter-temporal valuations of past water managers. Although they may not have been optimized in a formal sense, in mature water resource systems with economic water demands, reservoir storage rules evolve via a socio-political process to embody societies' valuation of water. This empirical, ‘positive’, or descriptive valuation is captured by calibrating a hydro-economic model such that carry-over storage value functions enable simulated storage to match a historical benchmark. This paper compares both valuations for California's Central Valley revealing that carryover storage values derived from historical operations are typically greater than prescribed values. This leads to a greater reliance on groundwater use in historical operations than would have been achieved with system-wide optimization. More generally, comparing the two approaches to water valuations can provide insights into managers' attitudes as well as the impact of regulatory and institutional constraints they have to deal with – and that are not necessarily included in optimization models.

The reduction of damage due to water pollution requires good knowledge of the quality of surface waters. The Water Quality Monitoring Networks (WQMNs) have evolved over time according to the objectives of each one of them: knowledge of long-term quality evolution, search for the origin of pollution, detection of accidental pollution, etc. Information provided by WQMNs could be improved by a spatial approach, optimizing the location or the number of monitoring stations, or by a temporal approach, optimizing the sampling frequency. However, there is a cost for monitoring water quality.

In this article, we show, for the first time, how the estimation of the Economic Value of Information (EVOI) can be used to determine the spatio-temporal design of the network. With the example of a network that aims to detect accidental pollution, we show how to calculate the EVOI according to the spatial and temporal network design (number and location of stations, temporal accuracy of measurement) and how to define this design by maximizing the EVOI. This will allow us to answer questions such as: Are the expenses invested in the networks justified? With an additional budget, is it better to add a station or to increase the temporal accuracy of the measurement of existing stations? What is the optimal spatial and temporal design of the network when working with a fixed budget?

Excess nutrients have led to eutrophication of the Chesapeake Bay, USA. It has been suggested that oyster restoration can play an important role in achieving water quality goals in the Bay. An optimal control bioeconomic model is applied to the management of oysters in the Chesapeake Bay, taking into account nutrient removal by the oysters. Optimal management of oyster harvests in the Bay reduces the cost of attaining water quality goals by 4–6% relative to an open access fishery. A “naïve” management optimization that maximizes discounted net revenues from oyster harvests but that does not take into account their nitrogen impacts performs almost as well as the fully optimal solution. Sensitivity analyses show that the optimal oyster harvest depends on the cost of reducing nitrogen loadings from point and nonpoint sources through best management practices. Further, denitrification by living oysters is a much more important process than nutrient removal through harvest.

We conduct a contingent valuation study to estimate the willingness to pay for a point-of-use water quality technology and water quality testing services in the highlands of Guatemala. This study is unique in two ways: we measure drinking water quality at the household level through water samples collected at the household and we elicit the willingness to pay for water quality testing services. We find a significant divergence in subjects’ perceptions of water quality and the measured bacteria counts in their household water. This divergence is economically important as perceptions may play a significant role in willingness to pay for water quality improvements.

This paper studies the conflict between economic and environmental sustainability objectives faced by a water agency when she allocates water quotas to farmers. This conflict consists in a water allocation problem between the amount of water claimed by farmers to irrigate their crops and the water flows needed for the conservation and the preservation of the ecosystems. This conflict in objectives is analysed in a dynamic hydro-economic model in discrete-time using the viability approach. The viability kernel that defines the states of the resource yielding intertemporal feasible paths able to satisfy the set of constraints over time is analytically identified. The associated set of viable quota policies and the trade-off between food production and ecosystem conservation objectives are characterized. The theoretical results of the paper are illustrated with numerical simulations based on the Western La Mancha aquifer in Spain.

The European Water Framework Directive (WFD) strongly emphasizes that all water polluting sectors must enhance the protection of water bodies in a cost-effective way. River Basin Management Plans need to be made to achieve a good environmental status for all water bodies by 2027 at the latest. This article examines three principal water protection measures used in forestry: buffer zones, overland flow fields and sedimentation ponds. We analytically develop marginal abatement cost functions for each of these measures and apply them numerically for the Finnish forestry. We find that the marginal abatement costs of nutrients using buffer zones in clear-cut mineral soil forests are very high, as they entail leaving financially mature and uncut trees. In contrast, the marginal costs of using overland flow fields in conjunction with ditch cleaning and clear-cutting in peatlands are very low. Furthermore, for sediments using overland flow fields as a water protection measure entails significantly lower abatement costs than does using sedimentation ponds in conjunction with ditch cleaning in peatland forests. A cost-effective solution in a river basin entails that the highest nutrient reductions are made in agriculture but that forestry also does its share. A cost-effective allocation of abatement measures entails that the proportions of the overall nutrient reduction are 3% (1%) in forestry and 97% (99%) in agriculture when the reduction target is set as 10% (30%).

Agriculture in sub-Saharan Africa (SSA) countries is predominantly rainfed, but SSA could develop greater dependence on supplemental irrigation due to a changing climate with greater rainfall uncertainty and higher frequency of dry spells. Supplemental irrigation through small-scale water harvesting (SSWH) plays a vital role in helping rainfed small-scale farmers overcome the risk of dry spells and promotes greater investment in agriculture. This study employs a contingent valuation approach to estimate the demand for SSWH supplemental irrigation in Ghana. The study finds the mean willingness-to-pay estimates for SSWH supplemental irrigation to be GHC 25.36 (USD 6.67) per acre per season for open canal irrigation system and 24.76 (USD 6.52) per acre per season for pipeline irrigation system. Drought experience, access to credit, agricultural income, and land ownership are key determinants of the demand for SSWH supplemental irrigation. The findings are particularly important for pricing small-scale irrigation services from rainwater harvesting public water reservoirs. The study recommends that investing in rainwater harvesting in rainfed agriculture should form a cornerstone of any country's strategy for adapting to drought, particularly in developing countries where rainfed agriculture plays an important economic role.

An urban water network with storage and uncertain environmental water inflows is modelled. This three period model is analytically tractable, and allows for a straightforward study of the relative economic impact of different policy regimes. The model is used to identify the water authority's first best pricing policy, and its relation to long run marginal cost pricing. The model is then used to identify the implications of adopting the most commonly used rationing method when environmental flows are uncertain: setting a smoothed priced (often LRMC exclusive of scarcity value) and using moral suasion, rather than pricing, to control the demand for water. The optimal manner to address water security is also addressed.

We use a split-sample choice experiment to investigate the effects of alternative payment modes on the purchase of flood insurance among smallholder irrigation farmers in Ghana. Results show that insurance up-take is lower for insurance premium payments required in labour than comparable premiums required in harvest and money. The marginal willingness-to-pay for a one-year reduction in flood frequency is about 6 h in labour time, 30 kg in rice and 144 Ghana Cedis (US$37) per annum. The price elasticities of demand for flood insurance indicate an inelastic demand for insurance premiums under these three payment modes. In addition to revealing strong preferences for flood risk reduction among farmers in this region, these results imply that subsidy policies may be inadequate in increasing the purchase of weather insurance under these three payment modes.