March 21 - AOASS Obregon

First up today we attended the offices of AOASS in Obregon which is a farmer foundation based organisation which works with a great deal of co-operation. This way the interests of farmers are very well supported, particularly in areas of water/irrigation rights, marketing of product, and supply of seed, fertilizer, insurance, financial services, grain storage etc. Our main area of focus was to gain an understanding into the water resource and how irrigation supply and distribution is managed in the Yaqui Valley.

To set the scene, Obregon like most of Mexico is hot and dry with little rain. There are no major river systems with a limitless water source, instead there is a minor mountain range which acts as a catchment for rainfall. These mountains shed their rainfall into 3 dams which then supply the Yaqui and Mayo valleys - a total of about 136,000 ha. Mostly wheat is grown but also corn, vegetables, peas, safflower, table grapes and citrus. In 2003 and 2004 a drought created much hardship and plans were implemented to sink wells into underground aquifers to supplement surface water. Last year and again this year, less than desirable rain has fallen in the mountains and resources are being tested. These people understand the value of water and are acutely aware of their dependence upon it. Their very existence relies on these water reserves. So how is this extremely valuable water resource managed? Here are my observations.

Canal that services irrigation community

The first thing to be aware of is the water in storage is owned by Government. They charge (low rates) to the farmer owned water delivery company for use of this water, and they in turn recover this charge plus some, to the end users which are farmers, industry and some urban use. Water is run within 2 major open but lined canals each approx 120 km long with lots of service off takes to supply farmers.





In 2004 the farmer based group came together to plan and implement a co-ordinated strategy to sink 330 wells (bores) throughout the valley. This water is injected into the canals or direct on farms depending on location. This created an opportunity to install a modern irrigation infastructure system. A hydro-electric scheme was installed to generate electricity from the flow out of the dam. 

Strong Catholic Jesus overlooking dam

Master control panel

What really impressed me was the level of technical merit that their new systems incorpated. In fact I have never seen a more advanced and logical design. Studies have determined the amount of recharge on the underground aquifers  so when the wells were installed, sensors were attached on all 330 to provide real time data on the aquifer levels to ensure fantastic monitoring of this precious resource.



A strict and disciplined policy is adopted to ensure over-extraction does not occur. All the data that is collected and relayed back to a master control panel which is manned 24 hours every day. This master control panel operates each and every well on demand as required. Each well is equipped with a camera and microphone for a visual. The motors/pumps have oil sensors on them to allow the control panel to check oil levels and monitor temperatures. The wells are fenced and detectors are alerted if there are intruders within the compound. There is a large master map of the valley hanging on the control room wall with lights to indicate which wells are running at any one time. Lots of data of individual pumping volumes is streamed in and recorded. Really impressive!!!.

Reminds me of country around Glendambo

To summarize, the evolution of this water-challenged irrigation district has created opportunity to mitigate risks associated with water scarcity - as was the case for these people in the 2003/4 drought - and low surface water storages will return. However they have determined recharge volumes for their underground water which allows them to adopt sustainable extraction levels and be assured of this reserve into the future. There are of course still risk elements and challenges ahead. For example, a city to the north which is outside the valley now wants water from the dams to supply their growing population.  Lobbying of Government is taking place for access to this resource. Perhaps desalination may assist in future supply for these growing coastal cities.

For anyone who is involved or interested in the practise of water management I can recommend the above scheme as one that is certainly worthy of following. I can provide contact details should anyone want more information or an introduction.