Between 2019 and 2020 the National Water Commission (With water) conducted work on rehabilitation of the Zocoteaca diversion damin Oaxacawhich receives the waters from the Mixteco Riverwhich runs through the south of Puebla and from which Puebla livestock producers benefit, without even having conducted an environmental impact study prior to the works.
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According to the National Autonomous University of Mexico (UNAM), a diversion dam “It is a work of collecting surface water and consists of a permanent construction in the form of a spillway that is placed across the width of the channel of a river or stream and can be extracted by gravity.”
In other words, this type of infrastructure has the purpose of avoiding the release of rapids by building vessels that distribute excess liquid. Ideally, these projects should not affect the natural flow of water.
According to Francisco Javier Sánchez Ruiz, PhD in Chemical Engineering from the Michoacana University of San Nicolás de Hidalgo (UMSNH) and academic at the Popular Autonomous University of the State of Puebla (UPAEP), there are several legal loopholes that allow Conagua to exempt the preparation of an environmental impact manifest (MIA) for this type of projects, but warned that the agency cannot ignore the presentation of a remediation and ecological care plan, especially due to the regional ecosystem implications.
For its part, Rodolfo Diaz Reyes, an engineer in Agronomy from the Technological Institute of the Valley of Oaxaca, maintained that all hydraulic works in the country must be approved with an environmental impact study involved, unless, in fact, no ecological damage is caused. However, he mentioned that the characteristics of this work are questionable.
In a request for information made through the National Transparency Platform (PNT), the federal agency was questioned about whether Whether or not the maintenance project carried out on the reservoir was based on an environmental impact studysince residents of the Mixteca region of Puebla denounced that the dam limited the flow of water during the dry season, causing several ecological and economic effects to the region.
Given this, the Conagua explained that it was between 2019 and 2020 when a recovery project was carried out for the Zocoteaca diversion dam, located in the municipality of Santiago Tamazola, Oaxaca.
The above in order to restore its operation, after the infrastructure was damaged during the passage of tropical storm Narda through this area of the country. The work was carried out with money from the Federal Hydraulic Infrastructure Insurance Company.
However, the federal agency recognized that the project was carried out without having a prior environmental impact study. This action was authorized by the Ministry of the Environment and Natural Resources itself (Semarnat), Conagua argued in document with folio 330009424001462.
It is worth remembering that it was in mid-March when the Mixteco River stopped its flow towards the state of Puebla, causing the water body to dry completely. This situation affected livestock activities in the region, but also the ecosystems.
According to residents of the municipalities of Piaxtla, Acatlán de Osorio, Tecomatlán and Axutla, The lack of water in the tributary occurred after the Zocoteaca diversion dam caused a significant amount of water to not continue its flow towards Puebla.
The case was attended to by the President of the Republic, Andrés Manuel López Obrador, who in his press conference on May 7 asked the head of Conagua, Germán Martínez, to address the problem and verify if said reservoir affected the river bed. Mixtec.
Although this publishing house repeatedly requested information from the Social Communication area of the federal agency, it was never granted. However, as of May 8, one day after the intervention of the national leader, inhabitants of the Mixteca of Puebla They reported that the tributary had water again. However, doubt prevails in the community about the influence that the prisoner had in this situation.
Doubts about the authority’s response
In an interview with El Sol de Puebla, Díaz Reyes warned that the response given by Conagua to the request for information is questionable, since the agency argued that the rehabilitation of the Zocoteaca diversion dam It was made after it was damaged during a natural disaster.
In most cases, the specialist said, restoration work after an event of this nature entails actions such as the removal and management of debris, as well as the desilting of the channel, among other. Therefore, he emphasized that this type of works necessarily requires the authorization of an environmental impact statement.
In other words, although the law allows natural and legal persons to exempt the submission of this type of environmental studies, this is only possible when, in effect, there is not the slightest risk of ecological damage.
For Díaz Reyes, it is very possible that the rehabilitation of the diversion dam, which was affected by a storm in 2019, has generated some type of waste that was eventually taken to another site, thus generating the need to prepare an EIS.
“All hydraulic works, whether rehabilitated or new, must have environmental impact studies or statements, because they are works that are in federal channels (…) When Tropical Storm Earl passed in the Sierra Norte and caused damage “The environmental impact statements had to be made strongly, because trees that were in the channel were moved up and, due to lack of maintenance, the cleaning of the channels had not been carried out and, for this, MIA was required.”considered.
Legal loopholes
According to Sánchez Ruiz, In Mexico there are various legal loopholes that prevent water projects such as the Zocoteaca diversion dam from complying with ecological flow guidelines.
From their perspective, said federal agency is not exempt from executing projects that safeguard local ecosystems. This includes those where the diversion of water can exacerbate the dryness of a stream, and this causes damage to ecosystems.
“For this type of case, all environmental impact studies should be completed, because by having one we know how you are going to protect the flow of these rivers without reaching a total loss. The projections that are made based on these climatic conditions, and these derivations that have been made to this dam, indicate that the Mixteco River will be lost in approximately two years,” the UPAEP academic explained.
He also warned that the lack of a strategy harmonized with the Mexican Standard NMX-AA-159-SCFI-2012, which establishes that hydraulic works must be refined with an ecological flow plan, will exacerbate the degradation of the flora and fauna dependent on the water flow of the Mixteco River.
Without ecological flow protection
Regarding this last point, Conagua was questioned about the ecological flow guidelines stipulated for the Zocoteaca diversion dam. This refers to the concession limits that a water body must have to prevent its overexploitation from affecting the ecosystems that survive thanks to the flow.
In other words, they consulted on the measures it has to prevent the flora and fauna located on the banks of the Mixteco River and surrounding areas would be affected by the lack of water therein.
This questioning was based on the analysis provided by Victor Orlando Magaña Ruedadoctor in Atmospheric Sciences from the University of California and academic from the National Autonomous University of Mexico (UNAM), who warned that the ecological flow regime is scarce in the country.
However, Conagua pointed out that, because the dam was built since 1991, to date an ecosystem protection mechanism has not been established in this regard.
On the other hand, the agency was consulted about the guidelines that are taken into account for guarantee good use of the water retained in the dam. However, the response was that the agency lacks regulations for the use of the reservoir, since its use falls entirely on the concessionaires of the irrigation units in Oaxaca.
Derived from the above, it was also requested to know the number of files initiated from the alleged misuse of the dam, however, the response from the federal agency was that, at least since 2019, no administrative procedure has been initiated for said acts.
Besides, Conagua indicated that there is no express obligation to guarantee water supply to the communities of Puebla, since no physical or legal person from the state has requested the concession of the service in said region. For this reason, he acknowledged that there is no “plan or forecast to provide water” to said Puebla districts.
In that sense, the federal agency also explained that it is the municipalities that have the constitutional obligation to provide water services to their inhabitants, and not exactly Conagua.
In this regard, Díaz Reyes made reference to the denial argued by Conagua in the request for information, where he indicated that the liquid from the Zocoteaca diversion dam is not currently concessioned, arguing that the function of the reservoir is not to accumulate the resource.
According to the specialist, the federal agency “went off on a tangent” pointing out that it does not have a list of concessionaires, as it specified that a dam of this type cannot function without having at least one user, otherwise its use would be unjustified.
In this sense, the agronomist explained that the organization must make transparent the use given to the water obtained through the reservoir, since, otherwise, all the liquid would have to continue without any restriction in its natural channel, which crosses the Puebla Mixtec.
Similarly, the specialist pointed out that the response given by Conagua, regarding ““There are no operating regulations for the dam,” does not adjust to reality, since he pointed out that national legislation is clear in stating that, as a river decreases its flow, the authority must proportionally distribute the water from the reservoirs, among other actions.
Otherwise, if there is no decrease in the distribution of the liquid in the Zocoteaca diversion dam, it is very possible that the water will reach the communities of Puebla to a lesser extent, even downstream, the expert emphasized.
Finally, Sánchez Ruiz criticized that Conagua must reform its internal guidelinesso that its capabilities are not limited to the administration of water resources or their monitoring, since it considered that many of the country’s hydraulic works, such as the Zocoteaca diversion dam, are carried out without having an impact statement. environmental, which eventually causes irreversible ecological damage.
