Présentations Colloques

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4.01
Session 4.01: Innovative economic instruments and institutions for achieving sustained groundwater use. Integrated socio-economic and biophysical modeling for groundwater and conjunctive use management
Zekri Slim
Institutional Approaches for Groundwater Management in Coastal Aquifers- An Empirical Analysis
Groundwater management is a hotly debated issue with few successful practical solutions. In coastal zones, groundwater over-pumping is the major cause of seawater intrusion and salinization of aquifers. The excuses for the absence of monitoring and management have often been explained by the high cost and lack of appropriate technology. In this paper we present a case study where smart groundwater metering is used to measure daily pumping. The results show that measuring pumping and allocating groundwater quotas are necessary but not sufficient to address the problem of a common pool resource. In our research a hydro-economic model was used+ MODFOLW-SEAWAT, and coupled to two dynamic optimization economic models with a simulation run over a period of 70 years. The first model is agent based where each farmer behaves in an uncoordinated manner with non-restricted access to groundwater. The second is an utopic model which maximizes the present value of total benefits from all farms while taking into consideration the long term effects of pumping on the aquifer’s salinity. The models were developed with the aim of assessing the optimal institutional framework for groundwater regulation and management. Results show that the allocation of groundwater rights proportionally or uniformly would reduce groundwater volumes pumped but would not be sufficient to protect the aquifer from salinization. However, when groundwater rights are complemented by a reduction of irrigated land, establishment of groundwater markets among farmers, and adoption of efficient irrigation technology, the salinity of the aquifer is improved progressively. The results also show that farmers will not invest in efficient irrigation systems unless water quotas are established and monitored. This paper estimates the economic gains of monitoring groundwater and the contribution of each of the policy measures in achieving resiliency and sustainability of a coastal aquifer management.
Oman