The conflict for water in the Lerma- Chapala river basin and the water distribution agreement POLIOPTRO F. MARTÍNEZ-AUSTRIA MEXICAN INSTITUTE FOR WATER TECHNOLOGY Scientific contribution on Integrated Water Management A CASE OF STUDY

The river basin

The water conflict / crisis

Water Distribution Agreement A water distribution agreement was needed in order to: – A fair upstream-downstream water distribution – To assure a enviromental flow to the lake – Protect water rights The agreement was reached in the context of the first Basin Council at México

Scientific Contribution In the agreement negotiation, scientific contribution was fundamental, bringing: – Objective, independent point of view – Information – and knowledge – transfer to the parts. – Hydrological model: scenarios of water management – Facilitating the process

Dynamic model

Model components

Scenario analysis Scenarios 1)Modifying the 1991 agreement 2)Using rules based on optimization techniques. Irrigation guarantee criteria were considered such that a minimum supply of 50% of the concession volume for every irrigation system. Minimum conservation levels in Chapala Lake of 1000, 1500 and 2000 hm 3 The alternatives were simulated using a precipitation historical record of 52 years.

The consensus process IMTA provided: 1)Training in the use of the models to the members of the high- level technical group 2)Scientific and technological support and advice. 3)IMTA´s guidance to perform the analysis of climatic, water use and technological scenarios, as well as of solution options. After around 30,000 person-hours, an agreement was reached to define a so-called Joint Optimal Operational Policy. The models proved to be essential in the consensus building process, since they created the proper climate for discussions based on facts, rather than on opinions, thus making it possible to overcome the existing impasse.

Conclusions Scientific basin knowledge and proper technological tools proved to be essential in the analysis of scenarios and solution options for a complex set of water-related problems in the face of intense competition for the resource. Science and technology proved to be essential in building consensus among stakeholders with conflicting positions, in order to define sustainable water management schemes. The agreement establishes operational rules for the distribution of water, seeking to satisfy as much of the agricultural demand as is physically possible and to preserve the Chapala Lake, and includes a Joint Optimal Operational Policy in one of its clauses, as well as a reference to the models as decision-making tools. The agreement was signed by the five state governors with the presence of the President of Mexico as honorary witness and by the agricultural users.

Thank you Knowledge and technology for integrated water management

Mexican Institute for Water Technology 5 TH WORLD WATER FORUM Region Americas Meeting Polioptro Martínez-Austria Adaptation to climate change