[Coral-List] Reference to address necessary measures to minimize environmental impact of a desalination plant

[Dennis Hubbard]

Hi Valerie:

Fortunately, this is not a new topic and I THINK that the main issues are
well delineated. The first is more clear-cut but technically more
difficult. It is critical that the effluent be released below the ocean
thermocline (ideally 300m but probably more practically 100 meters). The
second is to use measures to eliminate or significantly reduce physical
damage during installation. Surveys to reduce the physical contact with
corals and other locally important species (i.e., those that have less
ability to return quickly) can be very valuable in siting the pipeline
corridor. While some have argued that carefully placing effluent pipes is a
simple matter, I would argue that the post-project damage assessments I
have read suggest that either this is not the case or the folks doing the
installations were complete imbeciles.

It has also been my experience that engineers and "planners" place a higher
premium on economics and aesthetics above water than on avoiding damage
offshore. A critical decision will be based on the likely damage potential
related to floating a pre-assembled pipe to the shelf edge versus having
divers assemble the pipeline section by section. One the one hand, it is
VERY tricky to lower a long pipeline into even a broad corridor without
landing on corals and other sensitive organisms (including divers). On the
other hand, "death by a thousand cuts" may be the outcome of divers
lowering and assembling individual lengths of pipe.

One other consideration -  marine scientists that are well educated in
ecological dynamics are often poorly versed in the practicalities of marine
construction. As a result, ecology and economy are too often in conflict
and we all know who the winner will be. So, it is VERY important to
identify the technical folks who appreciate the value of the marine
community but also know the intricacies of working with heavy equipment in
the shallow marine environment. It has been my experience that working with
colleagues who have backgrounds in the professional diving community (and
here I'm talking "oil field "grunts" and the like - not dive instructors).
I had years of experience working with this community during my tenure as
Science Coordinator of Hydrolab on St. Croix - and I often found that they
worried as much about the reefs as I did... and sometimes they were even
more restrictive than I argued for. If you want recommendations, let me
know; many of my professional-diving collaborators are on St. Croix and can
be trusted. I'd be happy to make a trip for pre-assessment if needed, but
they would be cheaper as they are closer.

Best,

Dennis

On Wed, Sep 9, 2020 at 7:51 AM Valerie Gregoire via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Good Day Dear Coral-Listers,
>
> I have a colleague, who is not on the list, that is working on a proposal
> for EIA report for a desalination plant in St.Kitts, Caribbean. In order to
> address the necessary measures to minimize the environmental impact of the
> desalination plant with the bine disposal as well as with the routing and
> placement of pipe, She is looking into guidelines, internationale standard.
> If anyone ever work into a desalination project and have some useful
> reference, please contact me. Thank you very much.
>
> Warms regards,
> Valerie Gregoire M.Sc.Marine Biology
> Tel: +1869-660-9415
> Email: vg.valeriegregoire at gmail.com
>
> _______________________________________________
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov
> https://coral.aoml.noaa.gov/mailman/listinfo/coral-list
>


-- 
Dennis Hubbard - Emeritus Professor: Dept of Geology-Oberlin College
Oberlin OH 44074
(440) 935-4014

* "When you get on the wrong train.... every stop is the wrong stop"*
 Benjamin Stein: "*Ludes, A Ballad of the Drug and the Dream*"