Facing unprecedented demands from the human population, fresh water supplies are being tapped at rates far in excess of recharge rates throughout the world. The global response to water scarcity has been one of "digging deeper" wells, which has provided relief for many populations but has also resulted in dramatic drops in water levels of aquifers around the world (See SED graphic). Aquifer depletion can allow surface contaminants or salt water to intrude into the aquifer or may lead to the surface itself subsiding into the depleted aquifer causing irreversible loss of that aquifer.
Unfortunately even in light of this unsustainable consumption, diarrheic disease due to contaminated drinking water remains a primary cause of childhood mortality. The environmental and public health challenges faced by Mexico embody many of these global struggles. Estimates made in 2005, for instance, suggest that about 17% of the Mexican population does not have access to drinking "water of the appropriate bacteriological quality." 1 . These figures, although staggering, reflect a common reality for many countries throughout the developed world.
Water Quality Survey Motivation
Water quality monitoring is essential to water management on a municipal or regional level, however even on the household level, sustainable water purification technologies must be informed about the character of contaminants in the local water supply. For example, SODIS (solar water disinfection) and solar distillation are two household level means of disinfecting water contaminated with biological pathogens, however only solar distillation is able to provide water clean from heavy metals, and salts. Thus local water surveys are an intrinsic component of developing sustainable water strategies in a given local. This fact emphasizes the need for a systematic effort to survey water quality before devising management strategies locally and globally.
Estuario de Punta Banda y Acuífero de Maneadero
Baja California Norte has a local population facing low incomes, poor water resources, and limited water infrastructure. Many people lack of access to a formal sewage system, many do not have access to well water and rely on water trucks to bring in non-potable water for household use. Those people who do have access to fresh water typically purchase it from water purification outlets and transport it home 1 .
The Maneadero aquifer also shows signs of a problem afflicting coastal aquifers throughout the world: salt water intrusion. The salinity of the wells in Maneadero have been found to be increasing over time which is a common consequence from overdrawing from coastal aquifers 2. The aquifer of Maneadero forms a contiguous water masses with the Punta Banda estuary. As the local population Maneadero draws its agricultural and household water from this aquifer, salt water from the estuary and Punta Banda bay intrude into the aquifer. Understanding the dynamic nature of water scarcity in this area requires that the rate of saline intrusion and water withdrawal be monitored.
Science for the People is initiating a multi-year survey of water quality in the area of Punta Banda and Maneadero. This survey makes use of low-cost, portable, and relatively simple but accurate water quality measurement devices. In addition to providing data on the local water quality this effort is also a test of the feasibility of autonomous, low cost, small scale, water quality surveys in developing world conditions globally. The results of this water quality survey are accessible via the Eco-map and archived online.
1. Children's Health and the Environment in North America: A first report on available indicators and measures. Country Report: Mexico. Secretariat of Health- Mexico. December 2005.
2. Geochemical evolution of groundwater in the Maneadero coastal aquifer during a dry year in Baja California, Mexico L. Walter Daessle', Edith C. Sanchez, Victor F. Camacho-Ibar, Leopoldo G. Mendoza-Espinosa, Jose D. Carriquiry, Victor A. Macias, Pedro G. Castro