Water Resource Notebook of Guadeloupe

The Caribbean Geophysical and Numerical Research Group is proud to announce the publication of the first notebook on the water resource of Guadeloupe edited by OREC Guadeloupe (Regional Energy & Climate Observatory) named « LA RESSOURCE EN EAU ET LE CHANGEMENT CLIMATIQUE » (WATER RESOURCE AND CLIMATE CHANGE)

This document is the fruit of the collaborative work of the technical committee of the water resource of the Regional Climate Expert Group of Guadeloupe composed by ten members form University of Antilles, BRGM (French Geological and Mining Research Office), IPGP-OBSERA (Earth Physic Institute of Paris – Observatory of water and erosion in the French West Indies), INRAe (French National Institute of Agronomic Research and Environment), Flè Kawbon (Carbon Flower -Design Office-), Office de l’Eau Guadeloupe (Water Office of Guadeloupe), TCGNRG and supervised by OREC Guadeloupe (Mrs Cynthia Bonine and Amélie Belfort).

The writing of the document has been committed to Jean-François Dorville et Romain Rochette who could not go to the end of this project by lack of time.

The document is intended for institutions and the general public. It inventors the available resource, presents the climatic projections and theirs expected effects but also the possible actions to mitigate them.

The document is composed of 40 pages, 22 illustrations, 4 tables and 20 pictures. It is organized in four parts:

  • A presentation of climate of Guadeloupe and its main features
  • An inventory of the water resource, mainly those which benefit from an administrative following.
  • A presentation of the climate prevision, mainly those which come from C3AF up to 2080 (IPPC RCP8.5 scenario), and their expected effects on the water resource and their usage.
  • A presentation of levers of action, means and methods available to mitigate the future effects

The document if freely downloadable in French on that link : Cahier_de_l_eau

A long abstract will be available soon

TCGNRG hopes that it will become a reference in the Caribbean area. We still available to answer to any questions on the field (contact@tcgnrg.com)

YouTube link of the video of presentation (in French with subtitle) : YouTube

Link to press article

RCI Guadeloupe (13/11/2020) : https://www.rci.fm/guadeloupe/infos/Environnement/Un-cahier-pour-comprendre-la-ressource-en-eau-et-le-changement-climatique-en

France Antilles Guadeloupe (11/11/2020) : https://www.guadeloupe.franceantilles.fr/actualite/environnement/un-webinaire-sur-la-ressource-en-eau-en-guadeloupe-et-le-changement-climatique-580152.php

France Antilles Guadeloupe (17/11/2020): https://www.guadeloupe.franceantilles.fr/actualite/environnement/nos-enfants-devront-apprendre-a-economiser-l-eau-580483.php

Meilleurs vœux 2020

Toute l’équipe de TCGNRG vous souhaite une excellente année 2020 à vous et vos proches !

Dans un environnement où tout semble s’accélérer au point de vue physique l’Humain doit rester au centre du problème en interaction forte avec son milieu (l’eau, la terre, l’air et la vie).

Nos peurs ne proviennent que de nos manques de compréhension ou de l’absence de vérité…The Caribbean Geophysical and Numerical Research Group (Le Groupe de Recherche Caribéen en Géophysique et Systèmes Numériques) aide à la compréhension, l’acquisition et la maîtrise des savoirs à l’échelle du globe ou de la ville.

TCGNRG propose des solutions dans des domaines allant de la production eau douce, l’évaluation des énergies renouvelables, la gestion des échouages de sargasses, la pollution marine et atmosphérique et l’atténuation des risques naturelles.

Best wishes for 2020

All TCG•NRG wish you and your relatives a Happy New Year 2020!

In an environment where everything seems to be accelerating from a Physical point of view, Human being must remain at the centre in strong interaction with her / his environment (i.e., water, earth, air and life)

Our fears only come from lack of understanding or absence of truth… The Caribbean Geophysical and Numerical Research Group helps to understand, acquire and master knowledge at the scale of the earth or a city

TCG•NRG offers solutions in areas ranging from freshwater production, renewable energy assessment, management of sargassum stranding, marine and atmospheric pollution and natural hazards mitigation.

CARISCIENCE 2019 – Guadeloupe

From October 20th to October 22th 2019 University of Antilles at the Fouillole Campus in Guadeloupe hold the annual meeting of the CAS (Caribbean Academia of Science) and of CARISCIENCE.

The conference CARISCIENCE 2019 “CARIBBEAN SCIENCE AND INNOVATION MEETING” was the opportunity to award Dr. S. Haque for important work she done in Astrophysics, research of life in the Universe and popularization of science through action for youth and scientific TV show.

It was also the opportunity for Pr E. Calais of the ENS France (French Higher National School) to reaffirmed the high utility and need of the Geoscience in the Caribbean. By his presentation “Research, Training and Innovation in Earth Science: a Caribbean perspective?” Professor Calais list main applications can be done by the geoscience to the community. One can regret that his presentation was essentially focused on Natural Hazard and did not mention utility for every day and life quality. In any case The Caribbean Geophysical and Numerical Research Group policy and aim was indirectly confirmed by this presentation. He validated again the project defended by TCG•NRG at the scale of the Caribbean region.

The two days of conference was focus on four main themes : Biodiversity; Health; Agronomy; Risk and Chemistry.

The session organized are listed bellow:

  • Biodiversity & Health;
  • Biodiversity-Chemistry;
  • Risk;
  • Chemistry;
  • Biodiversity & Agronomy.

The large diversity of theme present during this conference was the opportunity for the TCGNRG to present part of two studies done in collaboration with students of UWI Mona and the Physics Department at the Faculty of Science and Technology.

A poster on wave energy potential around Jamaica by Alton Daley : “The First Steps Towards The Realization Of Energy From Oceanic Waves In Jamaica”. Alton present in this poster some interesting result of his Mphil study, particularly sea state around Jamaica. The poster is accessible on this link.

The second work is an oral presentation on a first LoRa experimentation for sensor network in Jamaica. This work is part of the Zachary William Mphil and #JamGreenDesal project : Using LoRa P2P NetworkforAutonomous Seawater Quality Monitor for Green Powering Desalination Plant

Initial poster which should presented before change by organizer in oral presentation is available on this link.

The work presented during this conference were of good quality with many interesting subject focused on the Caribbean area one can site the presentation on conch of Dr. Dalila Aldana-Aranda : “Scientific Cooperation in the Caribbean: Queen conch (Mollusca) as indicator of Climatic Change.”

National French Air Quality Day (9/18/2019)

France is celebrating its National Air Quality Day on 18 September under the auspices of the Ministry of Ecological and Solidarity Transition.

The quality of the air to a minimum of three essential elements :

  • we live permanently in the atmosphere, apart from short passages in liquid media, between 0 and 15km above the surface of the water (atmospheric boundary layer), our skin and most of our mucous membranes are in permanent contact with the air and these compounds;
  • we must inhale at least 10 to 30 thousand litres of air in a day to produce the energy needed for life using available oxygen;
  • High concentration and diversity of fine particles and airborne molecules in air mostly composed by nitrogen (78%), oxygen (21%) and other gas.
Sketch of Atmospheric Boundary Layer

Human activities, geological (volcanism), meteorological (sand haze) and biological (fermentation of wet packed algae) in amount of other can perturb air quality over more or less long period.
In order to qualitatively and quantitatively assess quality of the air in which we move and we breathe, index have been put in place.
It is based on the determination of a value or a colour indicating the quality compared to a normal air or the risk related to particular particles or molecules.

In front of the considerable number of particle, the indices group several sees all the pollutants.
The atmospheric index (ATMO index) used in France takes into account Ozone (O3), Sulphur dioxide (SO2), Nitrogen dioxide NO2 and PM10 (particle up to 10 micrometres in diameter). Future evolutions predict the use of PM25.

Value of pollutants concentration used to compute ATMO Index

The information of the air quality must be correlated with our behaviour.
Placed in a rubbish bin all aware human being will seek to extract itself quickly, except special mission. An atmosphere of poor quality should be avoided.

It is therefore unfortunate that the information on atmospheric indices is not clearly required to avoid immediate risk behaviours such as smoky plumes from charcoal smokers (a large producer of fine particles) or run along roads and motorways at the end of the day at busy times.
Talking about situations that are not palpable enough (i.e., not visible or too far away) does not allow the conceptualization of pollution, makes the notion too abstract and does not allow the acceptance of behaviour that has a strong impact on lifestyles and the economy. But ensures a better, healthier, more peaceful and less violent life.

Information, especially the one which was worked to produce index, means something and must be understood and accepted. TCGNRG participates in this understanding and awareness with the help of adapted training, advices and atmospheric modelling and human behaviour, do not hesitate to contact us for more information.

Atmospheric Index at worldwide scale  : https://waqi.info/fr/

International Sargassum Conference, Guadeloupe 2019 : a first analyse

From 23 to 26 October Regional Council of Guadeloupe wants to be the convergent point of know-how and techniques for mitigating Sargassum algae effects through the organization of the international conference financed by the European program of regional cooperation InterReg Caraïbe.

The objectives of this conference were presented during the steering committee set up on April 16, 2016 are

  • better understand the Sargassum phenomenon at the Caribbean level;
  • share experiences in collection, processing and recovery of algae;
  • sign on the international political agenda issues of massive sargassum invasion.

The answer to the first point can only come from research and technological innovations. This objective therefore requires a real investment in competent human resources.

The second point raises the question of the effectiveness of methods already tested, all of which have major drawbacks which considerably aggravate the environmental resource. The current level of knowledge is too limited to assess medium and long-term consequences.

The third point, on the other hand, is a pious wish. How politically collaborate to mitigate a phenomenon whose origins and modes of growth, spatial and temporal distribution, are as poorly known. The absence of boundaries and natural barriers when pelagic algae is advected makes it necessary to regulate invasion situations at local scales. The hope of have a turnkey solution rests solely on the convictions of predatory vendors.

A first analysis

Fig. 1: Distribution of subjects in hourly amount during the International Conference Sargassum2019 in Guadeloupe, FWI

The planning for the international conference was unveiled last week (week # 36). Without access to the detailed program, a quantitative analysis can be conducted nevertheless to understand the essence of this conference.

During the four days of that event, we can note the large number of communication actions with the public screening of a documentary , a televised debate, a public debate and a press conference with a total duration of 5h52 min (2h30min + 1h30min + 1h + 52min).

The state of knowledge, reserved to the first day is limited to 3h15min, coffee break included. The rest of the day is planned for the TV debate and presentation of the projects selected for the Sargassum call for projects .

Experience sharing of Friday, October 25th 2019 seems more provided spread over 4h30min, leaving the best place to the case of the Dominican Republic and Mexico, where their main issues are the preservation of sites operated by the tourism industry (>8 M of visitors for 2018 in Quintana Roo -Mexican state- and >6.5 M to Dominican Republic). The rest of the day is reserved for presentation of funding opportunities and the public debate.

The last day dealt with the cooperation to fight sargassum and international strategies during almost 3 hours. We hope that this morning will allow states and territories which are all concurrent in tourism, fishing and marine mining resources, to take stock of the situation put theirs differences other side and share their human resources and knowledges. Announced presence of the Prime ministry of the French Republic, Édouard Philippe, should not change nothing. Despite the Paris Agreement France are doing little choice in favour of nature and public health.


This succinct analysis gives a vision of the objectives of this conference, unfortunately far from the TCGNRG vision and possibly of the resolution of this situation.

It should be remembered what the named Sargassum crisis is in fact an imbalance of nutriments (nitrogen, phosphorus, etc.) across the Atlantic and most of the coastal area which promote the growth of algae. We must noted that during their pelagic phase the growth and reproduction (by cuttings) rates of Sargassum algae is not stopped.

To this imbalance one must added a structural and intellectual incapacity to rethink the management of organic matter in an overly industrialized environmental system.

Remarkable Sites and Stranding of Sargassum : the dangerous Door of Hell (Porte d’Enfer)

Sargassum (Sargassum fluitans and natans) have been the main species of visible pelagic floating algae since 2011, stranded on the Caribbean coast. Their stranding are strongly influenced by sea currents and configuration of the coastlines (human making included). Arrival of dense or scattered rafts causes ecological disturbances because of the quantity of organic matter (composed by carbon C, hydrogen H, Oxygen O, Nitrogen N, Phosphorus P and sulphur S) which it brings and the speed of stranding. Rafts of Sargassum move under effects of wind, waves, sea currents and tide. They are home to a wide variety of plankton, fish and shellfish colonies. Sargassum oxygen needs coupled with the poor quality of shallow coastal waters cause asphyxiation and anoxic decomposition -fermentation- generating toxic gases such as hydrogen sulphide (H2S), ammonia (NH3), thiols (R -SH) but also greenhouse gases such as methane (CH4).

These processes of decomposition without oxygen are the subject of many controversies, health, economic and ecological crises. The solutions adopted in the French West Indies are mechanized pickups and emergency dredging, causing extensive destruction of beaches and harbours. The concentrations of two of the most toxic gases (H2S & NH3) are controlled so that populations can be evacuated if there is a risk. Despite measured rates of more than 10ppm H2S (Limit Value-Short-Term Exposure VLCT) no evacuation has been done since 2011.

Remarkable sites

Many beaches are considered to be remarkable sites. They attract many visitors and constitute the tourism potential of our developing countries. The presence of sargassum causes degradation of bathing water quality, landscape potential and air quality. These sites, which are highlighted and exploited by the tourism industry, offer significant profitability due to the lack of maintenance required to date.

The management of these sites is mostly complex and is pooling of many stakeholders, but this can not in any case justify their long-term pollution.

Porte-d-Enfer Beach

Map describing the configuration of Porte-d’Enfer beach and creek

The range of Porte-d-Enfer (16.48 ° N, 61.44 ° W) in Anse-Bertrand (known as the Trou à Man Coco) has been known for the last years of numerous massive sargassum stranding massive (see photo) provoking the fact of its geographical configuration the partial or complete blockage of the creek and a thick layer (more than 15 cm in height) of decomposed compacted algae. Under favourable conditions the production of bio-gases takes place on the whole column of wet Sargassum. It can be observed by the presence of bubbles (under columns shape) or by the dispersion of biofilms of sulpho-reducing bacteria greyish colour on the surface.

In these cases of mass stranding (example September 2018, January and July 2019) swimming is impossible and dangerous for health. The presence in the zone (up to 500m) of the basin is risky because the production of biogas is important, non-homogeneous and highly variable. The temperature of the water favours the production of hydrogen sulphide (H2S) and ammonia (NH3) during the sunniest hours of the day (9am-5pm) and therefore the risk during periods of affluence. Time variations such as wind failure or pressure drops favour high concentrations.

Cleaning – mitigating the effects of stranding

The site is naturally cleaned during the phases of strong increase of swell which warranty a ebb of the organic matter and the re-oxygenation of the basin.

The rainy season lets in the mouth which encourages the ebb and feeding of the sand beach.

The mechanized methods of collection are put in place by the municipality and the services of the French State are only for small quantity stranded algae. An attempt to set up a floating dam was a failure. Collection with crawler excavator help to strongly damaged the beach and nearby roads as well as pollution from petroleum products (see image of a tractor-excavator).

Manual cleaning stay the more efficient and ecologically respectful of the site, but unfortunately it is not set up.

Protection of populations

There have been 22 surveys of H2S and NH3 since 2018 with 15-minute portable measurements. No measures have indicated overtaking of the limit values ​​for exposure, the maximum values ​​recorded are 1.9 ppm for H2S (24/04/2018) and 36 ppm for NH3 (28/05/2018). We can question the validity of these measures when we know that the potential area of ​​biogas production in case of total coverage is 14,000m2 while stranding areas producing biogas is rarely greater than 5,000m2 in Guadeloupe (case of the fishing port of Capesterre-Belle-Eau). Comments made by users in the area confirm this question.

Nevertheless, these measurements are much higher than the chronic and sub-chronic exposure limits of 0.02 ppm for H2S and 0.714 ppm for NH3 [HCSP 08/06/2018]. The sub-chronic exhibition is an exhibition of one to several months which was the case between March and July 2018 according to the statements published by the ARS Guadeloupe (i.e., Regional Health Agency).

Two last values of H2S measured Thursday, July 18, 2019 and Monday, August 12th 2019 reach respectively 5.2 and 4.2 pm which are alert values (>5 ppm) for workers in French Labour Law.

No signboard is visible to alert passers-by (and tourists) of the health risks during periods of beaching and fumes of toxic gas. Without knowledge of the site, many passers-by, children and the elderly, admire the stranding without taking into account the serious health risk.

In the case of the crisis of green algae (Ulva aka sea-lettuce) of Brittany it took nearly ten years, dead wild boars, horses, dogs and several joggers before appearing on the beaches of official information boards.

It is therefore urgent to recognize that human health is worth more than the reputation (or image) of a tourist site. It is essential that the authorities protect people and tourists by intelligently informing about the non-permanent risk of stranding sargassum. This is particularly true for territories that rely on sustainable tourism development.

The Caribbean Geophysics and Numerical Research Group (TCGNRG) remains at your disposal to assist you (communities, collection companies and individuals) to secure the best places taking into account environmental conditions.

Last update (9/07/2019)

Since 20 August 2019 a municipal decree (see photo above) prohibits all nautical activities. This first plain decision of common sense is to be commended. But despite all the poor visibility of the display and the lack of pictogram for people who do not read the French prevents to really warn the risks associated with the presence of anoxic decomposing (fermentation) seaweed for more than two months.

At the moment the photos were taken an under water spear fisherman was coming out of the water without noticing the posters

Guadeloupe Sargassum 2019 : International event


From October 23 to 26, Guadeloupe organizes an event on Sargasso at the regional level (America – Caribbean). At eight (8) weeks of this event let’s make a point of situation.

It should be noted that at least two events have already occurred in 2019 on the subject in the Caribbean area :


The limited information available nevertheless allows to know that there will be a trade fair Sargass’Expo aiming to gather exhibitors around of (in order of importance)

  • remote sensing – prevision;
  • collection;
  • recovery;
  • storage;
  • and health surveillance.

We may be surprised that the sanitary surveillance is thus misplaced, knowing that the main impact of sargassum is first sanitary with olfactory risks (potential complete loss of smell), ocular, cardiac, respiratory, intestinal, etc. In 2018 in Martinique in 31 weeks more than 8500 consultations related to sargassum emanation were counted by the network of sentinel doctors.

The second event is the international scientific conference Sargassum2019. No information is currently available, only the steering committee was presented in April 15, 2019 . The lack of information (i.e. call for communication) and detailed program questions about its progress and the ability to produce useful information for people (residents, schoolchildren, workers, tourists, etc.) and economic actors impacted (fishermen, restaurateur, hotel keeper, sailing sector).

The third event which is Off of sargassum 2019 is a Caribbean Conference, from 19 to 22 October 2019. It is part of the Caribbean Science and Innovation Meeting. It will benefit the presence of some researchers on topics such as Biodiversity, Health, Natural Hazards, Renewable Energy and the Circular Economy. The latter seems much better organized, may produce very interesting results.
Deadline for registration is 16 September 2019 Contact the University of Antilles (Research Office).

TCGNRG wonders about the usefulness of using public funds to communicate on a subject where very little to any has been made since 2014. The methods used at this time are re-employment, most often come from construction industry in opposition with concepts of nature protection and biodiversity. The common sense might have been to wait until 2020 to organize a real cross-cutting conference on the topic on at least a week, giving scientists time to be really prepared.

Nevertheless, TCGNRG offer to individuals, institutions and government our services to assess, analyse or comment on information, methods and equipment will be presented during this event.

Feel free to contact our service : contact@tcgnrg.com

# JamGreenDesal Blog #4

Ability to be maintained at a certain rate or level : sustainability is an important concept developed those last thirty years when limits of our resources have been clearly identified (i.e., fossil fuel, minerals, sand, freshwater).

#JamGreenDesal presents in this fourth post how our freshwater resource is distributed and how modern life can impact it. Current situation with Climate Change and effective global warming as European countries which have experiencing higher temperature since modern methodology this summer (UK 38.5°C, France 46°C) push to figure out what will be our freshwater next month, next season and next century.

The sustainability of your provision in freshwater will depend of our usage and also the production. Green desalination can be part of the solution.

#GreenEnergy #EnergyNeed #RenewableEnergy #FreshWater #Desalination #ClimateChange #DrinkableWater #water #Cleanwater #AlternativeEnergy #Potablewater

A survey is still running to better understand relation between Jamaican and Freshwater, and how Jamaican consumed and manage freshwater. If you have 5 minutes and reside or have resided in Jamaica please help us and answer to the survey on this link

#JamGreenDesal Blog #Fr #3

Vert (Green en anglais) n’est pas seulement un mot à la mode, c’est aussi un concept fonctionnel qui tente de combler l’écart entre les lois de la Nature et les activités humaines. Les ressources limitées de la Terre ne peuvent que pousser l’être humain à utiliser de manière plus efficace et plus rationnelle l’énergie, les minéraux et les molécules organiques (matières végétales et animales).

Certaines personnes inconscientes pensent que nous pourrons trouver une deuxième planète à exploiter rapidement, mais cela ne sera pas le cas avant longtemps. Il est préférable de se concentrer sur ce qui est déjà disponible.

#EnergiesVertes #BesoinEnEnergie #EnergiesRenouvelables #Desalinisation #ChangementClimatique #EauPotable

Une enquête est toujours en cours pour mieux comprendre la relation entre la Jamaïque et l’eau douce. Si vous avez 5 minutes et que vous résidez ou avez résidé en Jamaïque, aidez-nous et répondez au sondage sur le lien.