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 |
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.
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