Irrigation in Mexico
Mexico, a classified arid and semi-arid country, has a total land area of 2 million square kilometres, 23% of which is equipped for irrigated agriculture.
Approximately 33,000 km2; correspond to 80 bigger systems, namely irrigation districts (Distritos de Riego – DR).
The remaining 29,000 km2; are distributed among more than 30 thousand small size communal and irrigation units (Unidades de Riego – UR).
Agricultural use accounts for 50% of this volume, mainly in the form of nonpoint discharges with high levels or residues for pesticides, fertilizers, and other chemicals.
Soil destruction is particularly pronounced in the north and northwest, with more than 60% of land considered in a total or accelerated state of erosion.
Fragmented because of its semiarid and arid character, the soil in this region has become increasingly damaged through excessive irrigation with waters high in salt.
[3] Irrigation development in Mexico was a governmental concern during the Porfiriato[4] and was affected by the Mexican Revolution and the agrarian reform.
Land reform, a stepping stone of post-Revolutionary governments, was closely related to irrigation projects.
During the 1940s and 1950s, River Basin Commissions were created to launch regional development programs sustained by water-related projects.
The National Program, implemented by CONAGUA, originally planned the transfer of operation and maintenance of 21 irrigation districts, comprising 1.98million ha.
CONAGUA should coordinate investments in the water sector, setting priorities reflecting each river basin's actual situation.
[2] Officers from both Government agencies have close contact and relationships with the people managing the Irrigation Districts.
Agricultural producers who are interested in organizing a common irrigation systems form Water User Associations (WUA).
Despite the increasing role of agricultural producers, CONAGUA remains the sector's dominant player in terms of policies, subsidies, programs and norms.
[9] There are also the usual legal considerations that need to be checked when developing PPPs in any sector, such as legal restrictions on the type of PPP arrangement that can be entered into, relevant procurement rules for entering into PPPs, existence of restrictions on foreign investment, taxation and potential for tax holidays and the ability to assign rights such as security and step in rights to lenders.
A significant share of resources spent in the sector, including both investment and recurrent expenditures, comes directly or indirectly from water users.
For example, in 2005, the Irrigation and Drainage Program (Programa Sectorial de Riego y Drenaje), was financed at 50% by CONAGUA, 15%by the States and 35% by farmers and the On-farm Irrigation Development Program (Programa de Desarrollo Parcelario), at 56% by CONAGUA, 5% by the States and 39% by farmers.
Hurricanes contribute to recharge surface and groundwater reservoirs with increased water supply for cities, irrigation and electricity generation.
The most severe droughts in Mexico in recent decades coincide with the variations in Pacific sea-surface temperatures associated with El Niño.
In 1996, four years of below normal rainfall produced farm losses estimated at US$1 billion and interstate political between Sonora and Sinaloa.
[11] Climate change will produce a decrease in water flow and an increase in water demand due to increasing temperature, decreasing rainfall and more extreme weather conditions such as droughts and floods due to El Niño-Southern Oscillation and La Niña.
[12] During some El Niño/La Niña years, winter precipitation may be so great that stream flow and water levels in dams may exceed those observed during summer.
In contrast, summer droughts during these events can lead to serious deficits in reservoir levels and in rain-fed maize production.
[13] In 1993, the World Bank approved a US$303 million loan to support an integrated irrigation modernization project.
[14] This project, whose closing date is 2009, aims to assist Mexico's government in its efforts to adopting a new model to improve the competitiveness of irrigated agriculture and the efficiency of irrigation water use, in both DRs and URs, that would include the development of partnerships between the public and private sectors as well as effective institutional collaboration within the public sector, plus the strengthening of a demand-driven approach to investment decisions and financing.
In June 2007, the Inter-American Development Bank (IDB) approved US$150,000 for an examination of the distributional effects of water reforms.
Parallel to decentralization, CONAGUA is promoting participatory processes in water management through the creation of river basin councils and regional offices conforming to hydrological boundaries.
