Optimizing Water Allocation under Uncertain System Conditions in Alfeios River Basin (Greece), Part A: Two-Stage Stochastic Programming Model with Deterministic Boundary Intervals

Abstract

Abstract:The enactment of the Water Framework Directive, constituting the basis of the European water policy, introduced various challenges and complexities for water resources management. River basins are exposed to a plethora of environmental stresses, resulting in degradation of their quantitative and qualitative status. This led to the reduction of clean available water, increasing competition among water users and imposing the need for optimal water allocation for each river unit. In most countries (including those in the Mediterranean), water resources management is characterized by lack of effective operational strategies combined with the absence of permanent measuring systems and low financial means, hampering the implementation of efficient river monitoring. Therefore, water resources management is indicated by high uncertainty and by imprecise and limited data, which may be easily approximated through estimates of intervals. In the present work, optimal water allocation under uncertain system conditions is undertaken for the Alfeios River Basin (Greece) based on an inexact two-stage stochastic programming methodology developed by Huang and Loucks (2000). It combines ordinary two-stage stochastic programming with uncertainties expressed as deterministic boundary intervals. Stable intervals for optimized water allocation targets and probabilistic water allocation and shortages are estimated under a baseline scenario and four water and agricultural policy future scenarios. OPEN ACCESSWater 2015, 7 5306

Optimizing Water Allocation under Uncertain System Conditions for Water and Agriculture Future Scenarios in Alfeios River Basin (Greece)—Part B: Fuzzy-Boundary Intervals Combined with Multi-Stage Stochastic Programming Model

“…The proposed modification is based on the generation of stochastic equal-probability hydrologic realizations/scenarios as thoroughly described in [38] using the stochastic software of CASTALIA [54][55][56]. CASTALIA is a system for the stochastic simulation and forecast of hydrologic variables, including (a) multivariate analysis (for many hydrologic processes, such as rain, temperature and discharge, and geographical correlated locations) and (b) multiple time scales (monthly and yearly) in a disaggregation framework.…”

“…The final step is the coupling of the two time scales through a linear disaggregation model [55]. A brief description of the process for the generation of fifty short-time equal-probability scenarios simultaneously for the monthly rain and temperature variables and the corresponding hydrologic simulation for the computation of the discharges at the main four subcatchments of the Alfeios river basin is included in Section 3.2 and the detailed description is given in [38].…”

“…This section describes briefly the information for the Alfeios required for the application of the FBISP method, since the thorough analysis of the hydrosystem is included in [38].…”

“…The other water-use sectors are hydropower generation and drinking water supply. As analyzed in [38], in Alfeios river basin, as in most Mediterranean countries, water resources management has been focused up to now on an essentially supply-driven approach. Authority responsibility relationships are fragmented and law enforcement and policy implementation are weak, facts that lead to the difficulty of gathering the necessary data for water resources management or even worst to data loss.…”

“…Changes on crop patterns, yields, subsidies, farmer income, variable input costs, market prices per agricultural product, fertilizers, and water and hydropower prices are some of the variables described into the narratives of these scenarios, which in turn serve as inputs into the optimization algorithm for the evaluation and the estimation of their effect on the water allocation pattern and the system benefits. Finally, for applying the above mentioned optimal water allocation methodology, benefit analysis of each water use identifying the unit benefit and unit penalties of each m 3 of water allocated to each one of the water uses has been undertaken for the Alfeios River in [38].…”