H23L-01
Analysis Challenges for Emerging Water Strategies and Conditions
Water management problems are always changing, both in the quantity and quality conditions of the water resources and in the management objectives sought by the society. Climatic changes, continued population growth, structural changes in the economy, continued emphasis on improving ecosystems, and changing demographics all pose major challenges for management and the analysis of water management alternatives and institutions. This talk will examine some of these challenges and present some promising deterministic and stochastic techniques and approaches employed to various water management problems in California for the management of estuaries, floods, droughts, and conflicts. Lessons learned from bringing these results to policy discussions will also be suggested. http://cee.engr.ucdavis.edu/faculty/lund/
H23L-02
Dynamic versus static allocation policies in multipurpose multireservoir systems
As the competition for water is likely to increase in the near future due to socioeconomic development and population growth, water resources managers will face hard choices when allocating water between competing users. Because water is a vital resource used in multiple sectors, including the environment, the allocation is inherently a political and social process, which is likely to become increasingly scrutinized as the competition grows between the different sectors. Since markets are usually absent or ineffective, the allocation of water between competing demands is achieved administratively taking into account key objectives such as economic efficiency, equity and maintaining the ecological integrity. When crop irrigation is involved, water is usually allocated by a system of annual rights to use a fixed, static, volume of water. In a fully-allocated basin, moving from a static to a dynamic allocation process, whereby the policies are regularly updated according to the hydrologic status of the river basin, is the first step towards the development of river basin management strategies that increase the productivity of water. More specifically, in a multipurpose multireservoir system, continuously adjusting release and withdrawal decisions based on the latest hydrologic information will increase the benefits derived from the system. However, the extent to which such an adjustment can be achieved results from complex spatial and temporal interactions between the physical characteristics of the water resources system (storage, natural flows), the economic and social consequences of rationing and the impacts on natural ecosystems. The complexity of the decision-making process, which requires the continuous evaluation of numerous trade-offs, calls for the use of integrated hydrologic-economic models. This paper compares static and dynamic management approaches for a cascade of hydropower-irrigation reservoirs using stochastic dual dynamic programming (SDDP) formulations. As its name indicates, SDDP is an extension of SDP that removes the curse of dimensionality found in discrete SDP and can therefore be used to analyze large-scale water resources systems. For the static approach, the multiobjective (irrigation-hydropower) optimization problem is solved using the constraint method, i.e. net benefits from hydropower generation are maximized and irrigation water withdrawals are additional constraints. In the dynamic approach, the SDDP model seeks to maximize the net benefits of both hydropower and irrigation crop production. A cascade of 8 reservoirs in the Turkish and Syrian parts of the Euphrates river basin is used as a case study.
H23L-03
The Value of Weather Forecast in Irrigation
This paper studies irrigation scheduling (when and how much water to apply during the crop growth season) in the Havana Lowlands region, Illinois, using meteorological, agronomic and agricultural production data from 2002. Irrigation scheduling determines the timing and amount of water applied to an irrigated cropland during the crop growing season. In this study a hydrologic-agronomic simulation is coupled with an optimization algorithm to search for the optimal irrigation schedule under various weather forecast horizons. The economic profit of irrigated corn from an optimized scheduling is compared to that from and the actual schedule, which is adopted from a pervious study. Extended and reliable climate prediction and weather forecast are found to be significantly valuable. If a weather forecast horizon is long enough to include the critical crop growth stage, in which crop yield bears the maximum loss over all stages, much economic loss can be avoided. Climate predictions of one to two months, which can cover the critical period, might be even more beneficial during a dry year. The other purpose of this paper is to analyze farmers' behavior in irrigation scheduling by comparing the "actual" schedule to the "optimized" ones. The ultimate goal of irrigation schedule optimization is to provide information to farmers so that they may modify their behavior. In practice, farmers' decision may not follow an optimal irrigation schedule due to the impact of various factors such as natural conditions, policies, farmers' habits and empirical knowledge, and the uncertain or inexact information that they receive. In this study farmers' behavior in irrigation decision making is analyzed by comparing the "actual" schedule to the "optimized" ones. This study finds that the identification of the crop growth stage with the most severe water stress is critical for irrigation scheduling. For the case study site in the year of 2002, framers' response to water stress was found to be late; they did not even respond appropriately to a major rainfall just 3 days ahead, which might be due to either an unreliable weather forecast or farmer's ignorance of the forecast.
H23L-04
Breaking the Logic of Groundwater-Led Agrarian Change in India
It is well known that the past groundwater led agrarian change in India is not sustainable and the major productivity growth in the agricultural sector over the last 50 years threatened. The groundwater economy in South Asia is characterized by the multitude (20 million in India alone) of individual private well owners who make independent extraction choices in an imperfect market environment. As a result and all over the subcontinent, dramatic regional aquifer depletion (100 to 150 m drops of groundwater levels in some regions) and soil salinization (20'000 to 30'000 ha lost to water logging and soil salinization annually) is observed. Considering that agriculture accounts for approximately 25% of India's GDP and employs nearly 62% of the population these observations are all the more worrisome. Consequently, India might turn from a major crop exporter (35 cubic km / a of freshwater equivalent presently or 50% of the annual average runoff of the Nile river) to a large volume staple food importer in the future so as to be able to feed its estimated population of 1.5 billion (2 billion) people by 2030 (2050). Apart from constantly worsening local employment opportunities, this development will most likely have repercussions on global food markets by causing substantial food commodity price increases on a world‐wide level. In order for policies to effectively address the problems related to groundwater irrigated agriculture in India, the micro foundations of the above mentioned macro level outcomes have to be properly understood. This is far from simple, given the complex fragmentation of the social, political and economic spaces in India and their intricate interplay. Examples of the latter are the targeted public food distribution systems. It will be argued that the outcomes to freshwater allocation, i.e. the absence or presence of certain institutional forms, are critically shaped by the place-dependent dialectic between nature and society. Thus, a prerequisite for the investigation of the trajectories of agrarian change is to properly account for social and natural system dynamics. For this purpose, an integrated, hierarchical computational modeling framework will be presented. More precisely, the agent-based allocation, production and trade model allows studying incomplete markets with few participants and limited information environments. It will help to identify mixed allocation baskets at different spatial scales. These baskets may consist to a variable degree of the allocation of renewable runoff, the development of renewable and non-renewable storage (e.g. rainwater harvesting, artificial groundwater recharge, surface reservoir, and fossil groundwater), investment in alternative sources (desalinization, wastewater reuse, inter-basin water transfer, etc.) and int. commodity trade so as to increase system resilience of economic activity. With such model, local and regional policy interventions (such as cap and trade, differential pricing, etc.) can be tested and consequently ranked based on benchmarks of observable outcomes. These benchmarks include sustainability, Pareto optimality, equitability and the exposure to production risk. Case studies from the Gangetic Plain in Northern India will be presented. http://freshwateranddevelopment.blogspot.com/
H23L-05
Risk and Reward: Adaptive Reservoir Operations using Seasonal Climate Forecasts
A typical water manager's objectives consist of retaining enough water in the reservoir to meet urban demand over the decision period, and releasing remaining water to agriculture in accordance with demand. The goal is to release as much water as possible, but not so much that the urban demand is not met. As a result, there are tradeoffs between releasing more water from the reservoir, and improving the yield. The decision hinges on the assumption the water manager holds regarding the future inflows to the reservoir and the risk of an urban water shortfall that the manager is willing to bear. Here we explore the effects of the future inflows to the reservoir that are assumed in making reservoir release decisions. With a conservative assumption of inflows, the reservoir releases will be limited by the continuous need to conserve water for the future. This results in very high reservoir levels that are prepared to be drawn down when the chosen drought scenario occurs. An alternative to these approaches is one that embraces the known year to year variability in the probability of drought at a particular location. We term these approaches "dynamic" risk management and provide an example using real interannual streamflow forecasts applied to reservoir release decision making for Oros Reservoir, NE Brazil.
H23L-06
The role of price and enforcement in water allocation: insights from Game Theory
As many countries are moving towards water sector reforms, practical issues of how water management institutions can better effect allocation, regulation and enforcement of water rights have emerged. The uncertainty associated with water that is available at a particular diversion point becomes a parameter that is likely to influence the behavior of water users as to their application for water licenses, as well as their willingness to pay for licensed use. The ability of a water agency to reduce this uncertainty through effective water rights enforcement is related to the fiscal ability of the agency to sustain the enforcement effort. In this paper, this interplay across the users and the agency is explored, considering the hydraulic structure or sequence of water use, and parameters that define the users and the agency's economics. The potential for free rider behavior by the users, as well as their proposals for licensed use are derived conditional on this setting. The analyses presented are developed in the framework of the theory of "Law and Economics", with user interactions modeled as a game theoretic enterprise. The state of Ceara, Brazil is used loosely as an example setting, with parameter values for the experiments indexed to be approximately those relevant for current decisions. The potential for using the ideas in participatory decision making is discussed.
H23L-07
Hydrosystems Modeling in an Andean River Basin Under Development and Climate Change Scenarios
The Aconcagua river basin is located in the central zone of Chile, has a Mediterranean-type climate, and its runoff regime is markedly nivo-pluvial. Water main users include agriculture, mining, hydropower, industry and domestic supply. Rapid growth of land use for high-value crop agriculture and countrywide expansion of power demand has increased pressure over water resources in the Basin. On the other hand, integrated management of watershed resources is complicated by the fact that in Chile water rights become private property once allocated. This work demonstrates the development of a hydrologic-operational simulation model for the Aconcagua River Basin using the Water Evaluation and Plannning (WEAP) System, which allows to integrate diverse uses of the river basin and varied scenarios of development as well as hydrologic conditions. The proposed model is used to evaluate the performance of several development strategies with respect to stakeholders preferences, including infrastructure, land use change and conjunctive use of groundwater and surface water resources. Additionally, the influence of hydrologic and climatic uncertainty on water rights reliability and other typical management assumptions (such as the concept of hydrologically independent "river sections") is assessed by direct input of climate change scenarios contained in the IPCC IV report to the hydrologic model.
H23L-08
Using Water Transfers to Manage Supply Risk
Most cities currently rely on water supplies with sufficient capacity to meet demand under almost all conditions. However, the rising costs of water supply development make the maintenance of infrequently used excess capacity increasingly expensive, and more utilities are considering the use of water transfers as a means of more cost effectively meeting demand under drought conditions. Transfers can take place between utilities, as well as different user groups (e.g., municipal and agricultural), and can involve both treated and untreated water. In cases where both the "buyer" and "seller" draw water from the same supply, contractual agreements alone can facilitate a transfer, but in other cases new infrastructure (e.g., pipelines) will be required. Developing and valuing transfer agreements and/or infrastructure investments requires probabilistic supply/demand analyses that incorporate elements of both hydrology and economics. The complexity of these analyses increases as more sophisticated types of agreements (e. g., options) are considered, and as utilities begin to consider how to integrate transfers into long-term planning efforts involving a more diversified portfolio of supply assets. This discussion will revolve around the methods used to develop minimum (expected) cost portfolios of supply assets that meet specified reliability goals. Two different case studies, one in both the eastern and western U.S., will be described with attention to: the role that transfers can play in reducing average supply costs; tradeoffs between costs and supply reliability, and; the effects of different transfer agreement types on the infrastructure capacity required to complete the transfers. Results will provide insights into the cost savings potential of more flexible water supply strategies.