Water resources management in Mexico

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Mexico: Water Resources Management
Withdrawals by sector 1998 (%)	Agriculture 78% Industry 5% Domestic 17%
Land Area	vajkjejejdfhhhsdhawgvbsdgwerhrfhrfhujhter resources(surface water+groundwater-overlap)	409 km² (158 sq mi)
Surface water produced internally	361 km² (139 sq mi)
Groudwater recharge	139 km² (54 sq mi)
Overlap (shared by groundwater and surface water)	91 km² (35 sq mi)
Per capita	4,016 m² (43,230 sq ft)
Total natural renewable water resources	457 km² (176 sq mi)
Per capita natural renewable water resources	4,490 km² (1,730 sq mi)
Agricultural Land (% of land area)	56%
Total area equipped for irrigation (% of cultivated area)	22.9%
Irrigated area	Equipped 6.2 million ha (15.3 million acres) Actually irrigated 5.5 million ha (13.6 million acres)
Irrigation systems	surface irrigation 5.8 million ha (14.3 million acres) sprinkler irrigation 0.31 million ha (0.77 million acres) localized irrigation 0.14 million ha (0.35 million acres)
Wetland designated as Ramsar sites, 1986	53,178.57 km² (13,140,710 acres)
Hydropower generation (as a percentage of total electricity generation)	22%

Water resources management is one of Mexico's pressing concerns, and it is imposing heavy costs to the economy. The arid northwest and central regions contain 77% of Mexico's population and generate 85% of the gross domestic product (GDP). Poor southern regions have abundant water resources. Surface and groundwater are overexploited and polluted, leading to insufficient water availability to support economic development and environmental sustainability. The country has put in place a system of water resources management that includes both central (federal) and decentral (basin and local) institutions.

[edit] Water management history and recent developments

Mexico has a long and well-established tradition on water resources management (WRM) which started in the 1930s when the country began investing heavily in water storage facilities and groundwater development to expand irrigation and supply water to the rapidly expanding population.

The 1934 Código Agrario, promulgated during the Cárdenas administration (1934-1940), granted the federal government powers to define the “public interest” to which water could be harnessed. By virtue of such legislation, between the 1930s and 1970s, the rural community and ejido sector were subject to direct federal control over water ^(Sanderson). Private landowners, on the other hand, enjoyed the benefits of federally subsidized irrigation infrastructure and guaranteed market prices. Over time, large landowners became highly capitalized, while small land owners, by the 1970s, were suffering from the effects of water monopolies ^(Scott).

In the 1970s, the Mexican government entered into a tripartite agreement with the World Bank and the United Nations Development Program to prepare the 1975 National Water Plan (NWP), which identified the need to enact a New Water Law (NWL) and a National Water Authority (ANA) as well as decentralize responsibilities and promote water user participation in operational and maintenance (O&M). The NWP spurred a significant institutional development and infrastructural achievements: (i) the federal government transfer responsibilities for water supply and sanitation to municipalities and states in 1983, (ii) the Mexican Institute of Water Technology was established in 1986, (iii) the National Commission on Water ([1] CONAGUA) was established in 1988, and (iv) in 1989, the first Basin Council was created in Lerma Chapala, incorporating water users from multiple sectors.

During the 1990s, there was a rapid groundwater development and aquifer pumping for combined agricultural, urban, and industrial demand. Also the federal government decentralized responsibility for large irrigation infrastructure to autonomous agencies (irrigation districts).

In 1992, Mexico adopted the Ley de Aguas Nacionales (LAN), which contained specific provisions for the role of the CONAGUA, the structure and functioning of river basin councils, public participation in water management, etc. In 1993 the Cutzamala system, one of the largest pumping schemes in the world, was completed. The Cutzamala system pumps 19 cubic meters (670 cu ft) of water per second into the Mexico City metropolitan area.

In 1997 the first technical groundwater committee was created to manage an overexploited aquifer in the state of Guanajuato.

With the 2004 Revision of the National Water Law, the thirteen decentralized CNA regions would become basin organizations serving as the technical arm of more broad-based basin councils that incorporate civil society interests including the private sector and citizens’ groups ^(Scott).

[edit] Water resource base

[edit] Surface and ground water resources

Watersheds of Mexico. Basins in green drain to the Pacific, in brown to the Gulf of Mexico, and in yellow to the Caribbean Sea. Grey indicates interior basins that do not drain to the sea.

Mexico's internal renewable water resources per capita is 4,016 cubic meters (141,800 cu ft), which is below the average in the Central American and the Caribbean region, 6,645 cubic meters (234,700 cu ft).

A volume of 396 cubic kilometers (95 cu mi) of water per year flows through Mexico's rivers, including imports from other countries and excluding exports. A total of 65% of this surface runoff occurs in seven rivers: Grijalva, Usumacinta, Papaloapan, Coatzacoalcos, Balsas, Panuco, Santiago and Tonala, whose total watershed area represents 22% of the country's total land area. The Balsas and Santiago rivers empty on the Pacific Ocean, while the other five empty into the Gulf of Mexico ^(CONAGUAII).

The historical mean annual precipitation (1941-2004) is 773 mm (30.4 in), with 77% of all precipitation accruing between June and October. ^{(Earthtrends)} A little over 70% of rainwater in Mexico is evapotranspirated and returns to the atmosphere. The rest runs off rivers and streams or infiltrates into the subsoil and recharges groundwater ^(Aquastat).

Mexico shares three watersheds (Colorado, Bravo and Tijuana) with the United States of America (U.S.), four with Guatemala (Grijalva, Usumacintam Suchiate, Coatan, and Candelaria) and one with Belize and Guatemala (Rio Hondo). The waters are shared with the U.S. in accordance with the stipulations included in the Treaty on the Utilization of the Waters of the Colorado, Tijuana and Rio Grande Rivers, signed in 1944.

Groundwater accounts for 64% of the volume for public water supply, 33% of all water used for agriculture and livestock, and 24% of water utilized by self-supplied industry. There are 653 groundwater aquifers in Mexico. CONAGUA estimates the total amount of groundwater recharge to be around 77 cubic kilometers (18 cu mi) per year, 36.4% of which, (around 28 km³/6.7 cu mi per year) are actually used. This average rate does not fully represent the situation of the arid region, where a negative balance is threatening the sustainable use of groundwater resources.

Groundwater is a key water supplier for several users in the arid region or in some cities where groundwater is most of the time the sole water resource available. About 71% of the groundawater is used on agriculture, 20% on water urban supply and 3% for domestic and animal use ^(CONAGUA).

[edit] Storage capacity and infrastructure

Mexico counts with 4,000 dams and other hydraulic infrastructure with a storage capacity of 180 cubic kilometers (43 cu mi), which account for 44% of the annual flow. In the arid regions, dams are mostly used for irrigation. In the humid areas, dams are mostly used for electricity generation. Dams are also considered a means for flood protection in Mexico. Approximately 63 dams have a storage capacity of over 100 million cubic meters (81,000 acre feet), and account for 95% of Mexico's storage capacity ^(Aquastat). The largest dams are La Angostura (20,217 million m2), Nezahualcóyotl (14,0298 million m2), Chicoasén (11,883 million m2), and Infiernillo (11,860 million m2) ^{(Centro Virtual de Informacion del Agua)}.

Mexico has approximately 70 lakes with a storage capacity of 14 km³ (3.4 cu mi). The largest lake, the Chapala Lake, has a storage capacity of 8,126 cubic hectometres (1.950 cu mi).

Source: CONAGUA

[edit] Water quality

According to the Water Quality Index, 96% of Mexico's surface water bodies have different levels of pollution. OECD estimates the economic cost of water pollution in Mexico at US$6 billion per year. The problem is most serious in the Valle de Mexico region where 100% of the water bodies have different levels of contamination, 18% of which are highly polluted. Low water quality is due to untreated discharge of industrial effluents and municipal wastewater into rives and lakes, solid waste deposits along river banks, uncontrolled seepage from unsanitary landfills, and non-point pollution mainly from agricultural production ^(Olson).

CONAGUA has also detected infiltration if untreated municipal wastewater in 8 aquifers, iron and manganese in 2, arsenic in 1 aquifer of the Lagunera region. In overexploited aquifers, contamination tends to worsen over time as the groundwater reservoir is depleted. This is the case of the Lagunera region, where concentration of 0.09 to 0.59 mg/L of arsenic found in the drinking water, are above of the permissible level of 0.05 mg/L. In addition, information regarding water quality, available by the Public Water Rights and Registry, is often unreliable and data series scarce ^(Olson).

[edit] Water resources management by sector

[edit] Drinking water and sanitation

In 1998, domestic consumption accounted for 17% of surface water withdrawals in Mexico. During the past decade, the Mexican water supply and sanitation sector made major strides in service coverage. In urban areas almost 100% of the population is estimated to have access to improved water supply and 91% to adequate sanitation. In rural areas, the respective shares are 87% for water and 41% for sanitation. ^{(WHO and UNICEF)} Coverage levels are particularly low in the southern regions. (See also Water supply and sanitation in Mexico)

[edit] Irrigation and drainage

In 1998, agriculture accounted for 78% of surface water withdrawals in Mexico. A total of 6.2 million hectare (15.3 million acre) count with irrigation infrastructure (22.9% of the total cultivated area), 5.5 million hectares (13.6 million acres) of which are actually irrigated. In 1997, 5.8 million hectares (14.3 million acres) use surface irrigation, 0.3 million ha use sprinkler irrigation and 0.1 million ha localized irrigation. Ineffective irrigation has generated salinization and drainage problems in 3,841.63 square kilometres (949,290 acres) of a total irrigated area of 62,560 square kilometres (15,460,000 acres) ^(Aquastat). (See also Irrigation in Mexico)

[edit] Hydropower

The electricity sector in Mexico relies heavily on thermal sources (74% of total installed capacity), followed by hydropower generation (22%). The largest hydro plant in Mexico is the 2,300 MW Manuel Moreno Torres in Chicoasén, Chiapas. This is the world’s fourth most productive hydroelectric plant ^(EIA). (See also Electricity sector in Mexico)

[edit] Aquatic ecosystems

A Lepisosteus, one of the endemic species of Mexico

There are approximately 70 lakes in Mexico, covering a total area of 3,700 square kilometres (910,000 acres). Some of these lakes, especially in the Eastern side, have a volcanic origin and count with numerous endemic species. Lake Chapala, the largest Mexican lake, is considered a hydrological priority region for biodiversity conservation due to its 39 local species, 19 of which are endemic. The Lake Catemaco, located in Veracruz, has 12 native species 9 of which are endemic ^(Arriaga).

Wetlands in Mexico are dynamic, complex and productive ecosystems. Six major wetland are registered in the RAMSAR Convention on Wetlands: Lagartos River (Yucatan Peninsula), Cuatrocienagas (Coahuila), La Encrucijada (Chiapas), Marsh Nayarit and Sinaloa, Centla Swamp (Tabasco), and the Colorado River (Baja California).

Cenotes, sinkholes formed with groundwater, host a number of unique species from bacteria, algae and protozoa (i.e. copepoda, cladocera and rotifera) to vertebrates (i.e.lepisosteus) ^(Arriaga). Cenotes are the main water source for many ancient and contemporary Maya people, as there are no rivers and very few lakes on the peninsula.

[edit] Legal and institutional framework

[edit] Legal framework

The main law governing water resources management in Mexico is the National Water Law of 1992, revised on April 29, 2004 ^(Law).

According to the Law key functions in the sector are the responsibility of the federal government, through the National Water Commission (CNA or CONAGUA). The NWL made id possible to implement a regulatory framework that seeks to encourage greater efficiency and a more accurate perception of the social, economic, and environmental value of this resource. Therefore, users of national waters operate within a framework of rights and obligations that are clearly defined in three basic instruments:

• Titles of concession or allocation, which establish the right to withdraw, use or enjoy in usufruct a specific volume of water
• Permits for wastewater discharges. This instrument establishes the concession under which permittees must dispose of resulting wastewater
• Enrollment in the Public Registry of the Water Rights (Registro Publico de Derechos de Agua – REDPA) of both tittles of concession or allocation and permits for discharging wastewater, which affords the rights granted to water users greater certainty and assistance form a legal standpoint.

[edit] Institutional framework

Three groups of institutions have been assigned with the main responsibilities for WRM: (i) the National Water Commission (Comision Nacional del Agua –CONAGUA), at the federal level; (ii) Water Commissions (Comisiones Estatales del Agua – CEAs), at the State level; and (iii) basin authorities and basin councils.

CONAGUA is the highest institution for water resource management in Mexico, including water policy, water rights, planning, irrigation and drainage development, water supply and sanitation, and emergency and disaster management (with an emphasis on flooding). CONAGUA’s mission is to manage and preserve national water resources, with the participation of the society, to reach a sustainable use of the resource.

CONAGUA is formally under the authority of the Ministry of Environment and Natural Resources (Secretaria del Medio Ambiente y Recursos Naturales – SEMARNAT) but it enjoys considerable de facto autonomy. It employs 17,000 professionals, has 13 regional offices and 32 state offices and had an annual budget of US$1.2 billion in 2005. It also directly manages certain key hydraulic facilities such as the Cutzamala Pipeline that supplies a large share of the water used in the Metropolitan Area of Mexico City. CNA also owns and operates most dams in Mexico and operates the country’s water monitoring network^(Olson).

The CEAs are autonomous entities that usually are under the authority of the State Ministry of Public Works. Their attributions are different among states and can include water resources management, irrigation and the provision of water supply and sanitation services.

The recently created Basin Authorities (BAs) will develop from the 13 existing Regional Offices of CONAGUA and are expected to be responsible for formulating regional policy, designing programs to implement such policies, conducting studies to estimate the value of the financial resources generated within their boundaries (water user fees and service fees), recommending specific rates for water user fees and collecting them. Basin Councils (BCs) are expected to guide, together with CONAGUA, BAs work. There are a total of 25 BCs that have been established with the same basin boundaries as the BAs^(Olson).

[edit] Government strategy

The 2004 amended National Water Law (NWL) aims to restructure CONAGUA key functions through the transfer of responsibilities from the central level to subnational entities: the basin agencies (Organismos de Cuenca – BA) and Basin Councils (Consejos de Cuenca – BC). BA and BCs are expected to play an increasing role in the sector limiting CONAGUA’s role to the administration of the NWL, the conduct of national water policy, and planning, supervision, support and regulatory activities.

The NWL also introduced a Water Financing System (Sistema Finaciero del Agua – SFA). CONAGUA will create together with the Ministry of Finance appropriate instruments to determine funding sources, spending guidelines, cost recovery, settling of accounts and management indicators.

[edit] Water pricing, cost recovery and subsidies

Mexico lacks a coherent national policy framework for setting and linking water and sanitation tariffs, subsidies and cost-recovery goals. The absence of overarching policies produces a wide variation in the degree of cost recovery and subsidies across regions. Tariffs are set below costs – the most common form of user subsidy in water supply and sanitation.

Water service providers charge industrial and commercial user tariffs that are close to full recovery cost, and cross subsidize residential users. The average tariff across users, US$0.32 per cubic meter ($0.24/cu yd), is half the Latin American and the Caribbean average, US$0.65/m³ ($0.50/cu yd).

The level of collection efficiency in Mexico has been estimated at 72%, far below the levels achieved in developed countries (OECD 95%). Water tariff collections in water supply and sanitation have been estimated at US$1.54 billion in 2002. Billed revenues were estimated at between US$2.14 billion and US$2.9 billion.

Approximately 31% of water custumers are not metered and are charged a flat rate, independent of consumption, differentiated by neighborhood ^{(Olson and Saltiel)}.

[edit] Water-related risks

Hurricane Dean photographed by International Space Station astronauts

Mexico is prone to several weather events including hurricanes on both Pacific and Caribbean coasts. Hurricanes contribute to recharge surface and groundwater reservoirs with increases water supply for cities, irrigation and electricity generation. Hurricanes pose also a threat to service delivery, infrastructure and ultimately to ecosystems and human life. This situation is aggravated by deforestation upstream as well as human settlements located in flood prone areas ^(CONAGUA).

With more than 85% of the Mexican land area defined as arid or semi-arid and a highly variable interannual rainfall Mexico is also prone to droughts, especially in the northern areas. The most severe droughts in Mexico in recent decades coincide with the variations in Pacific sea-surface temperatures associated with El Niño. The economic and social and environmental impacts of droughts in Mexico are notable. In 1996, four years of below normal rainfall produced farms losses estimated at US$1 billion and interstate political between Sonora and Sinaloa ^(Liverman).

[edit] Potential climate change impacts

Sea surface skin temperature anomalies in November 2007 showing La Niña conditions

Climate change will produce a decrease in water flow and an increase on 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.

The IPCC estimates an increase in temperatures between 1 and 6 degrees Celsius. By 2050, the Mexican Institute of Water Technology expects a 7-12 % decrease in precipitation in the southern basins, 3% in the Mexican Golf basin, and 11% in the central basing. Precipitation is estimated to continue decreasing over the next 50 years. A diminished river flow will also contribute to higher evapotranspiration. There is also expected to see an increase on 5 category hurricanes ^(Martinez).

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. In Mexico during 1997, the estimated costs of climate anomalies associated with El Niño were 900 million US dollars, particularly in agricultural activities, when 2 million hectares (5 million acres) were affected by a severe drought. ^(Conde).

[edit] Ongoing programs and initiatives

The World Bank is currently contributing with US$28.5 million, to an Adaptation to Climate Change Project in the Gulf of Mexico ([2]). This project aims at formulating and implementing adaptation policy actions and specific measures in representative systems of Gulf of Mexico wetlands in order to protect their environmental functions and their rich biodiversity from climate change related impacts, and improving the knowledge base to ascertain with a higher level of certainty the anticipated impacts from climate change on the country’s water resources, with a primary focus on coastal wetlands and associated inland basins. The

In November 2007, the Inter-American Development Bank approved a US$200,000 project to support a program for flood emergency in Tabasco. In September 2007 it approved a US$200,000 project to support a program to relief damages caused by Hurricane Dean.

[edit] References

[edit] See also

• Electricity sector in Mexico
• Water supply and sanitation in Mexico
• Irrigation in Mexico
• Water resources in Mexico

[edit] External links

• Centro Virtual de Informacion del Agua
• CONAGUA official website