Managing water differently: Integrated Water Resources Management as a framework for adaptation to climate change in White Paper for the Environmental Working Group of the UC-Mexico Initiative

J. Pablo Ortiz-Partida 1, S. Sandoval-Solis 1, Jesús Arellano González1, Josué Medellín-Azuara1, J. Edward Taylor1 1. University of California, Davis

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Table of Contents

I. Abstract ...... 2 II. Introduction ...... 2 III. human welfare implications ...... 6 IV. binational context ...... 7 V. Theoretical framework ...... 7 VI. Policy responses and challenges ...... 9 VII. Scientific/historical background: What do we know? 9 VIII. Unanswered questions, research void ...... 12 IX. Thinking ahead: Priorities for future binational research and training initiatives ...... 12 X. Bibliography...... 14 Abstract

Climate change is expected to impact water availability and its management, with more frequent and extended droughts, more severe floods, and lower water quality. Water allocation policies, regulations and infrastructure in Mexico were not designed for changing future climate conditions. This document reviews the implications of climate change in water resources systems in Mexico, and evaluates how management strategies from California can serve as potential adaptation schemes towards an Integrated Water Resources Management framework in Mexico. Introduction

In Mexico, reduction on water availability as consequence of climate change not only compromises water reliability for industries and agriculture, but also augments the challenge to provide the most basic human right, drinking water. The understanding of the magnitude and extent to which human and natural systems will be affected by climate change is critical to better design policies that prepares for effective adaptation. According to the Intergovernmental Panel on Climate Change (IPCC), rising temperatures are expected to reduce renewable surface water and groundwater resources, vital inputs for people, agriculture, industry, and aquatic and riparian ecosystems (IPCC, 2014). As a result, Mexico is expected to experience major impacts on water availability and supply, compromising food security, infrastructure, and agriculture income. In this context, Integrated Water Resources Management (IWRM) is a powerful and important framework to examine adaptation to climate change. IWRM is defined as “a process which promotes the coordinated development and management of water, land and related resources in order to maximize economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems” (Global Water Partnership, 2000).

In addition, changes on climate patterns are expected to increase drought years, having particular impacts on agriculture; and at the same time intensify rain events, augmenting flood risks in certain areas (Herrera-Pantoja & Hiscock, 2015). Mexico is already facing other water problem expected to aggravate as the changes on climate occur. The Water Advisory Council (CCA, 2016) using data from the National Water Commission of Mexico (CONAGUA) noted a series of facts to be considered for improving the current situation and prepare for the upcoming water issues: (1) 22.7 % of surface water is heavily contaminated; (2) national potable water and sewage coverage are 91.6% and 90.2% respectively; (3) 77% of water is used by agriculture; (4) conveyance and distribution of water have an efficiency of 86% and 76% respectively; (5) 16.2% of aquifers are under overdraft conditions; (6) about 40% of urban water is lost through system leaks; and (7) less than 50% of waste waters are treated.

México has an extensive territory with varied climatic conditions where water availability does not match with water demands. The two thirds of the territory with the highes