Reservoirs: How to Prepare for a Big Flood?

Reservoirs: How to Prepare for a Big Flood?

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By By Tec. Gladys B. Leiva and Noelia L. Saumell

This work is an analysis of the report carried out by the Government of the City of Buenos Aires on the Environmental Impacts that the work will present in the Operation and Construction Stages, as recorded on the website of the Government of the City (Hyperlink Rain Reservoirs ), presented in thirteen zipped files.

Dear friends:
On various occasions, the Secretary of Public Works of the City of Buenos Aires pointed out that it was not necessary to carry out the Environmental Impact Assessment of the reservoirs for flood control under the terms required by law 123. One of the arguments used is that this The Secretariat had carried out the corresponding studies and the result was that the works would have a low environmental impact. To demonstrate this, these studies were posted on a website. Beyond the basic principle that the studies should be controlled by someone other than the one who made them, we began to read what the rationale was for considering such large works as having a low environmental impact. Reading those reports is amazing. The absence of significant aspects, the lack of detail on substantive issues and the excess of information that is useless for the intended purpose is striking. For example, there is no forecast of the impact thousands of heavy trucks will have on kilometers of pavement that are not prepared to support their weight. On the other hand, we have data on the sanctuary of the Virgen del Buen Aire in Genoa (which gave its name to the City of Buenos Aires), or on the number of attendees at the Recoleta Cultural Center. In this issue, you receive an analysis of the so-called environmental impact study on the reservoirs, prepared by Gladys Beatriz Leiva and Noelia Lorena Saumell. We also indicate the website on which they are published, so that you can see them and form your own opinion about it. My opinion (both as an environmentalist and as a teacher) is that if the City Government's environmental impact study were a practical work presented by a university student, I don't know of any Chair willing to approve it. Perhaps it was the certainty of a postponement that led the Ministry of Public Works to evade the legal procedures for Environmental Impact Assessment. A big hug to all. Antonio Elio Brailovsky Deputy Ombudsman of the City of Buenos Aires Analysis of the technical reports on reservoirs presented by the city government on the website
This work is an analysis of the report carried out by the Government of the City of Buenos Aires on the Environmental Impacts that the work will present in the Operation and Construction Stages, as recorded on the website of the Government of the City (Hyperlink Rain Reservoirs ), presented in thirteen zipped files.

First of all, we want to highlight that (without giving any explanation) there are two reports from the City Government that are duplicates with minor differences.
This work will be divided into two parts
Ø Errors detected in the texts
Ø Errors by omission


The report does not contain the name of the author (s), the date of its completion and a very important issue to highlight: it does not specify which body (public or private) requested its completion.
Figures are cited which are numbered, but are not found in the report. The aforementioned data used in the report is at least 10 years old, and does not have projections, therefore they are obsolete to face a work of such magnitude.
The consulting firm HALCROW S.A. is cited. who made a report in the years 1965-1966 which is not relevant to be presented in this study, and assuming that they were relevant, these are outdated (36 years have passed), therefore, they cannot be taken into account.
There are references such as the "structure of the Population by Sex and Age", "Births, Deaths and Deaths of children under 1 year of age of residents in the City of Buenos Aires", "Attendees to the theaters of the City", among others, which are not relevant to the project to be carried out.

Throughout the report, the Municipality of Buenos Aires is mentioned, which ceased to be so 8 years ago, to be called GOVERNMENT OF THE AUTONOMOUS CITY OF BUENOS AIRES. If this is linked to the age of the data, it is concluded that a report prepared for another previous work is being used.When speaking of GREEN SPACES, the term used is incorrect since the term to be used is GREEN SPACES PUBLIC and has an average green space per inhabitant of 9.7 m2 when currently it is approximately 4.55 m2, including within the public green spaces the Costanera Sur Ecological Reserve and the Indo-American Park, constituting a total of 808 hectares.
It is incredible to accept that the pH of the Río de la Plata is 7.2 and that of the Arroyo Maldonado is 7.8. Since pH is used to indicate the degree of acidity of a solution, in this case that of bodies of water. The table containing these data was made by SIHN, an acronym that is not clarified at any time. The data indicated in the table were prepared in November 1989 and June 1990 without revealing which was the measurement for each year, methods used, number of samples, etc.
They state that on the reservoirs the area will be reforested and landscaped using a minimum of 30 cm up to one meter with "Fertile" sandy loam soil. Where our native vegetation is unlikely to thrive.
Regarding the Soil Drilling Sheets, they do not have any type of validity since they do not contain the Name and Surname of the person or persons who performed it or an identifying logo. Nor is it indicated who was the body that ordered the drilling and what was the reason for carrying out the same, while it is not specified which machinery was used or when it was made. That is, the protocols that indicate the reliability of the samples taken and the results obtained are missing. On the other hand, the number of samples taken is insufficient to ensure the results.
About the Environmental Impact Assessment Matrices, the GCBA presents three matrices, namely: Total Matrix, Matrix for the Construction Stage, and Matrix for the Operation Stage.
For this analysis we are based on the Total Matrix because the union of the Matrices for the Construction and Operation Stage results in the Total.
It is important to highlight the difference between the Matrix and the Environmental Impact Assessment reports both presented by the City Government due to the different analysis perspectives found in them, to the point that it seems that the matrix was prepared by another working group.

The most notable differences are as follows:

The report emphasizes that the project will be carried out in a densely urbanized area, which we can call an urban ecosystem, while when performing an analysis of the matrix it is not contemplated. As an example we will cite: that in the anthropogenic environment factors, the construction stage without relevant negative effect on deforestation and land preparation, soil maintenance and excavations, construction sites, movement of equipment and machines, and material production plants. This situation is not only of relevant negative effect but is in contrast to what has been said in the texts of the reports.
Continuing with the Construction Stage, in the Public Spaces variable the matrix indicates no significant negative effect on deforestation and land preparation. This is an uncertain qualification because it will produce a negative impact on a visual level, just like the bakeries. The same situation occurs in the variable Urban Landscape and Air Quality (Physical Environment).
The reverse situation occurs in the variable Public Spaces, Private Spaces, Urban Landscape, Quality of Life (Anthropic Environment); Soils and Air Quality (Physical Environment) and Biotic Environment (Biota) where the landscaping factor would have a relevant positive effect and not as indicated by the matrix without a relevant positive effect.
Continuing in the Construction Stage, it does not indicate in the Biotic Environment variable what effect the following factors exert: movement of soils and excavations, construction sites, movement of equipment and machinery, stockpiling of materials, noise and vibrations, layer depression and execution of work underground or tunnel.
In the Operation Stage, we emphasize that there is no factor that indicates even if it is not without relevant negative effect, which is striking.
We believe it is necessary to emphasize how the variable Labor Occupation is considered without a relevant positive effect for both stages, being that the generation of new jobs, even if they are temporary, is considered to have a relevant positive effect.
It should be noted that the references include special considerations, not clarifying what it refers to, and this is not a technical term used for classifying impacts.
Regarding the flow chart, it can be seen that it is highly confusing. The environmental components should coincide with the variables of the matrix, in the flowchart there are environmental components such as the value of private property, lost profits, local and regional incidence, odors and volatile materials that are not included in the matrix. In short, the flow chart is not useful for understanding the factors affected positively or negatively in the execution of the project.


All the study refers exclusively to the period of operation and construction of the reservoirs. There is no estimate of eventual effects during their operating period. Only the claim that these effects will not exist, without any foundation.
The useful life of the reservoirs is not indicated, which is essential to calculate the relationship between costs and benefits, both economic and environmental. It is not said what will be done with them at the end of their useful life.
No nuisance or eventuality is mentioned for regular maintenance or repair tasks, which will mean a period when the reservoirs are out of operation. No cost is mentioned for maintenance or eventual repairs, for events such as cracks produced in the structure by water or soil pressure, machinery failures, etc.
During the excavation period, the effects caused by the volume of earth extraction (approximately 500,000 cubic meters), its transfer and final disposal are not considered. As we do not know exactly how much land each truck carries and how many trucks are going to travel, we prefer not to express an opinion so as not to give false information.
The circulation of large trucks that will move the excavation material will affect not only the pavement of the city, but also private homes and commercial premises due to the vibrations caused by these trucks. There are no estimates of the damages and costs that this will cause to public and private property, but the experience of heavy traffic introduced in the La Boca and Barracas areas suggests that they will be very relevant. There, there has been damage to the pavement (including subsidence in several places), and significant cracks in buildings, in addition to damage to the health of people affected by noise and vibrations throughout the journey of the trucks.
Another issue that is not considered is the cleaning of trucks and machinery to be used that does not foresee where the washing waters will be discharged and how they will affect the sinks. That is, in what way will this land be prevented from covering the drains and causing new floods in other parts of the City of Buenos Aires.
The earth movement will bring with it the volatile particulate material that will directly affect the health of the residents of the area. No forecasts are seen in the report to cushion this effect.
If it is considered a rainy day, the trucks leave the works with muddy wheels, transporting the mud embedded in the wheels all the way. The risk of plugging sumps is not considered.
The affected area is a low area with a high and rapidly rising water level, which would aggravate the situation because they will be drilled by large diameter holes, which will produce a greater rise of the water tables, further aggravating the situation.
The cladding of the layers is not contemplated to avoid contamination caused by the underground cracks where the water infiltrates.
The soils of the City of Buenos Aires do not have stone strata that allow stable supports, but rather are very diverse soils.
Nowhere in the reports is the possibility of heavy rains in the construction period contemplated, a situation that will be aggravated by debris, construction sites, machinery, etc. that hinder the free circulation of drainage waters.
The report mentions that the reservoirs and tunnels are emptied by pumping stations with automatic ignition, but at no time is it mentioned the possibility that the automatic ignition does not work, so there should be an alternative mechanism.


In the first place, we want to emphasize that in 1988 a study carried out by the INCyTH (National Institute of Hydrological Sciences and Techniques), rejected the construction of reservoirs.
In turn, we want to mention that the acronym INCyTH appears at the bottom of the page in one of the reports provided by the City Government. INCYTH was a body dependent on the National Government and currently replaced by the National Institute of Water and the Environment. It is striking that it is included endorsing a work that he explicitly advised against doing. On the other hand, the body has been well chosen: since it no longer exists, INCITH will not be able to make an official denial.
It is not known that other alternative works have been estimated to solve the problem of flooding.
From what has been analyzed it appears that the terminology used is not very clear because the term Environmental Impact Assessment (EIA) is used, and no prior Environmental Impact Study (EIA) has apparently been carried out.
The following concepts are defined below:
Environmental Impact Study (EsIA) It must be carried out by the promoter and must predict the consequences of the execution of the project on the environment and establish corrective measures. Basically, it includes an environmental description of the project and the pre-operational situation of the environment that may be affected; the definition and assessment of the alterations that may occur, as well as the corrective measures aimed at eliminating and / or minimizing them; the establishment of a Monitoring and Recovery Program and the specification of the residual impacts that take place after applying the corrective measures.
The Environmental Impact Study is the nucleus around which the whole process is articulated.
Environmental Impact Assessment (EIA): It is the assessment of the possible damage that the work or activity may cause to the environment. It is carried out by the competent body for the Environment, bearing in mind the content of the study and the allegations that have been made in the information and public participation phase of the project.
Environmental Impact Statement (DIA): It is the opinion resulting from the administrative technical procedure of Environmental Impact Assessment, issued by the competent environmental body. It can be negative, preventing the project from being carried out or positive and conditioned.
Another point to consider is the approach given to Environmental Impact, if we consider that Environmental Impact is any alteration, favorable or unfavorable that occurs in the natural environment or in any of its components, caused by a project or activity, both public and private.
In a simple way, the value of the environmental impact can be defined as "the difference in value (loss or gain) suffered by the ecosystem after the action or impact".
I = Vi - Vf = DV
I = Impact
Vi = Initial value of the ecosystem
Vf = Final value of the ecosystem
DV = loss or gain of ecosystem value
Therefore, the impact of a project is the difference between the situation of the modified future environment, as it would manifest as a consequence of the activity, and the situation of the future environment as it would have evolved normally without it, that is, , the net change (positive or negative) resulting from the action.
The generic nature of the impact refers to its positive or negative consideration regarding the previous state of the action. Based on this, it can be beneficial or adverse.
The impact action type describes how the action effect is produced. It can be: Direct, indirect, synergistic or induced.
According to the spatial characteristics of the impact. This can be: Point effect, localized or extensive effect.
The period that the impact lasts can be: Temporary or Permanent (constant or intermittent)
The spatial basin of the impact reports on the dilution of its intensity in the spatial mosaic. It can be: Near the source or Far from the source.
The reversibility of the impact is the possibility, difficulty or impossibility of returning to the situation prior to the action by natural mechanisms. It can be: Reversible or Irreversible.
The possibility of recovery measures the loss caused, which can be recoverable or replaceable through human intervention or not. These can be: Recoverable or Irrecoverable.
Summarizing the previous concepts on the characteristics of the impacts we can define:
* Compatible impact: Lack of impact or immediate recovery after cessation of activity. No protective practices are needed.
* Moderate impact: Recovery from initial conditions requires some time. No protective practices are required.
* Severe impact: The magnitude of the impact requires, for the recovery of environmental conditions, the adaptation of protective practices. Recovery, even with these practices, requires a long period of time.
* Critical impact: The magnitude is higher than the acceptable threshold. There is a permanent loss of the quality of environmental conditions, without possible recovery, even with the adoption of corrective practices.
We consider it important to highlight that the drafting of the reports presented by the City Government does not differentiate, precisely, a series of stages and tasks to be fulfilled, which are basic to carry out the Environmental Impact Study (EsIA), several of which have not been carried out. The stages of a study of this nature are:
* Study of the activity to be carried out, specified in the proposed project, analysis and description of the project.
* Breakdown of the global project into elementary actions, of a homogeneous nature, in terms of their ability to generate impacts. Study of the phases related to construction, exploitation and abandonment. Prospecting of activities related to the initial project and induced activities.
* Definition of the pre-operational situation. Description of the physical environment in its biotic and abiotic elements in a wide area. Study of the socioeconomic environment.
* Meaning that, for its conservation, the most relevant elements of the previously inventoried medium have.
* Determination of the scope of application of the Environmental Impact Study, that is, definition of the necessary scope for each of the elements previously described.
* Identification of impacts. Repercussions that the programmed action may cause on the described environment. Magnitude of previously predicted impacts.
* Comparison and selection between alternatives, if any.
* Preventive and corrective measures: Possible detailed studies.
* Assessment of residual impacts.
* Surveillance and control plan
* Final report.

In other words, the report posted on the Internet by the Ministry of Public Works is not an Environmental Impact Study.

By Tec. Saumell

Video: Flood Control District has tips on how to be flood smart (June 2022).


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