Desalination Briefing Full Of Holes
John Kelly
Corpus Christi Light News
September 25, 2021
A presentation at the Tuesday, September 21 Council meeting was made by Michael Murphy director of the City’s desalination project to brief the Council on “unanswered questions.” In the end it was more like “if you can’t dazzle them with brilliance, baffle them with BS.” While Murphy and other proponents have tried to portray the opposition as no-nothing radicals Tuesday’s presentation confirms the City’s own deception on the issue.
The presentation which was lengthy and at times confusing, was made primarily by Murphy and Freese & Nichols (the engineering company hired to gain the permits). The major problem with the briefing was the omission of important facts and information.
An early part of Murphy’s presentation focused on the idea that droughts were more frequent and more intense. While this is true as the effects of climate change are increasing, this would also produce several arguments against desalination, especially with discharge in the bay. The refusal to examine relevant science and gas lighting of the public discredits the Council, City staff and Freese & Nichol and is certain to bring less trust in local government.
Other large desalination projects in the US
While Murphy and other proponents frequently mentioned the Carlsbad plant in San Diego and the Tampa Florida desalination plant they are not comparable to our situation and both have a cautionary history. Water from the Carlsbad plant costs seven dollars per thousand or $100 to $200 more per acre – foot than recycled water and $1000 more than an acre – foot of reservoir water. The plant which was originally supposed to cost approximately $225 million ended up costing over a billion. The plant, which discharges off shore, did increase the salinity but had no detrimental effects to organisms in the open water.
The plant was funded through bond sales which received the lowest investment rating from Fitch Ratings. At times the plant was only able to meet 70% of its water orders. Red tide incidents shut the plant down because of fouling of intake membranes. This is a huge concern as red tide incidents are expected to increase with further ocean warming.
The Tampa Bay facility does indeed discharge into the bay but with some strikingly different conditions. Tampa Bay is 400 mi.² and averages 12 feet deep, while Corpus Christi Bay is only 167 mi.² and 11 feet deep. It also has an abundance of freshwater discharge in the area around the desalination plant. The Hillsborough River discharges 1000 cubic feet per second into the bay near the plant. The Nueces River in contrast, discharges under 100 cubic feet per second. Also 1.4 billion g/d of cooling water are dumped in at the site by the power station next door.
While the price of water at the Tampa Bay facility is approximately three dollars per thousand, the plant opened five years late and more than $40 million over budget and a number of the companies involved in construction went bankrupt. That facility produces 10 million gallons a day approximately the size of the phase 1 proposed plan on the inner harbor.
Murphy admits the water is for industry and will raise residential rates.
Previously the Council staff had told the public that desalination would not increase water rates and that it wasn’t for industry. Murphy admitted that both the cost of construction and operation would be borne by the ratepayers. Currently use is about half industry and half residential and commercial. Murphy acknowledged that in fact the increased water supply would be to meet industrial needs.
Misleading environmental information
The City has cherry picked scientific information from the very beginning in its presentations to citizens, routinely ignoring or rejecting information provided by the scientific community. Numerous scientific papers that contradict the City’s position have been published since desalination was proposed.
The Council has never sought the advice of these professionals nor asked them to testify about their findings. Freese and Nichols which is contracted by the City to gain the permits, has likewise ignored the contrary reports. Without desalination it is unlikely Freese & Nichols would have a contract or that Murphy would be employed by the City.
One must ask why Larry McKinney PhD Director of the Harte Research Institute (HRI) and nationally known biologist, had to write for a piece in the local newspaper to be heard. His article said that desalination was a perfectly acceptable environmental process if both the intake and discharge were offshore and spoke against either in the bay.
Why not ask him and the foremost experts on local marine environments about the impact of desalination on the Bay? The Harte Research Institute and University of Texas Marine Science Institute are internationally recognized for their work.
The love of the dream of endless water
The City has spent ten years of dreaming about the “endless supply of water” that could be gained from desalinated ocean water. The problem they encountered was that putting the intake and discharge offshore as was normal made desalination financially noncompetitive. No one wanted to say “desal is not gonna work.” The staff and Council were still under the influence dream.
So they decided to make it work by cutting costs, just place the intake and discharge in a closed bay system. Something done nowhere else in the world.
Last year Gil Hernandez (D5) demanded a briefing on alternatives. The Council was presented with ten other proposals for water sources, none of which were given any further consideration by a Council who already had their mind set on desalination. Desalination is “sexy” and there a lot of historical emotional commitment to the concept.
Recommendations from the scientific research ignored.
Mountains of data have been gathered and hundreds of pages been written by members of the scientific community about the effects of desalination on Corpus Christi Bay. Excerpts from the studies with links to the complete study are covered below.
Murphy and the Freese & Nichols environmental engineer (who are both engineers) stated that they were using diffusers as recommended by the Harte Research Institute (HRI) implying that the project had HRI’s blessing, when actually HRI was only asked to recommend the best of limited options.
HRI issued a statement October 6, 2020 that stated, “The HRI report by Stunz and Montagna focused on biophysical impacts of discharge at specified areas designated by the city of Corpus Christi and did not evaluate water quality and contaminant issues.” It summarized its findings by stating, “HRI’s overall and primary conclusion in assessing potential desalination intake and discharge sites in Corpus Christi Bay was that an offshore location of intake and discharge would be the best option to minimize impacts on biota, habitats, and water quality.” HRI Water Quality Report
The HRI position paper also noted that they were not asked to examine the effects of any accumulation of toxic chemicals/heavy metals or the impact of the large inflow of hot brine. In other words the Freese and Nichols study only focused on salinity issues and their impact on a very narrow group of species.
The study, available for viewing on the City’s desalination website, only measures tolerances of highly adaptive sport fish species such as seatrout, redfish, black drum, flounder and shrimp. These particular species have a high tolerance for fluctuating salinity levels.
It ignored data on the effects of the other two variables affecting the species, temperature and contaminants such as heavy metals and chemicals. It ignored all three variables of temperature, salinity, metals and toxic chemicals on benthic, or bottom dwelling species. These species support the food chain in the bay that the sport fish species depend on.
In HRI’s evaluation of Freese and Nichols designated potential sites; three areas of concern involving desalination discharge were identified. Discharge is not simply salty water; it is concentrated salt brine that is hot, full of chemicals and heavy metals. All three of these things can cause environmental problems.
The work by Stunz and Magtagna found here make several pertinent statements:
Discharge at the Broadway wastewater treatment plant, “However, the conclusion from Hodges’2015 report is that desalination brine in the ship channel will likely result in extended periods of hypoxia and anoxia (little or no oxygen).”
“Ion imbalance of brine concentrate and ambient seawater mixing issues
The concentration of copper, calcium, chlorine, and anti-scalants in the brine concentrate needs to be determined before its impact can be assessed. Fish, plankton, and benthic fauna can experience toxic effects from the bioaccumulation of metals. Research is needed to verify the potential impacts of brine concentrate mixing with seawater.”
“Discharge location 1B is located in Corpus Christi Bay in the Ship Channel near Harbor Bridge. The proposed types of discharge infrastructure are submerged pipe and submerged jet diffusers. This site has previously been described as a depositional zone for material coming from the Inner Harbor (Carr et al. 1998). A submerged pipe would release a brine plume at the sediment surface of the bay. This pipe would be subject to fouling by sessile marine organisms such as serpulid worms and tunicates. Discharge location 1B may experience more wind-driven mixing than location 1A, potentially mixing up the brine plume released from a submerged pipe. However, hypoxia could still develop from the brine plume. Submerged jet diffusers are an alternative discharge type that prevents the formation of dense brine plumes. Turbidity from jet diffusers can cause developmental and filtration problems in bivalves.”
“Site 2: La Quinta Channel Extension Discharge location 2A is located southwest of La Quinta Channel Extension in Corpus Christi Bay. The proposed types of discharge infrastructure are submerged pipe and submerged jet diffusers. Nearby tidal flats, salt marshes, and seagrass beds are inhabited by protected bird species and used as recruitment areas by recreationally important fish species. Green sea turtles, bottlenose dolphins, and manatees have been observed in La Quinta Channel. Hypoxia or anoxia would occur as a result of submerged pipe brine plume discharge. This site would have the most severe environmental impacts and is not recommended for the construction of a discharge facility.”
“A discharge facility could be sited in the Inner Harbor with some potential biological impact for a small-scale demonstration desalination plant, but a full scale plant should not discharge here, because it would cause hypoxia or anoxia in the channel, and possibly eventually out into Corpus Christi Bay.”
A study regarding La Quinta Channel stated, “A discharge facility could be sited in the La Quinta Channel with some potential biological impact for a small-scale demonstration desalination plant, but a full scale plant at this location is least favorable, because it would cause hypoxia oranoxia in the channel, and possibly eventually out into Corpus Christi Bay.” And “For the reasons noted here and above, the La Quinta Channel sites are undesirable due to possible higher impacts to native biota and habitats.”
This literature review also revealed, “Multiport diffuser systems are a current state-of-the-art technique for mixing the concentrate in as small an area as possible to match ambient salinity of the surrounding water. This is the system planned for Corpus Christi. However, in smaller, contained areas, like within bays and ship channels where there is not adequate flushing, too large of a volume of concentrate will not mix, and it will eventually settle as a heavy seawater layer on the bottom and cause hypoxia or anoxia so that bottom-living organisms cannot survive.”
Tunnell continued, “Most recently, Dr. Ben Hodges modeled the possible release of brine discharge from the Corpus Christi desalination project into the main ship channel in Corpus Christi Bay. His conclusion of this concept of putting the brine into the channel and expecting it to transit out into the open ocean waters of the Gulf of Mexico for dilution “does not appear to be practical”. The result of 14 this action is likely to be “extended periods of hypoxia or anoxia in the ship channel” (Hodges 2015).
• Desalination discharge into the bay may also increase red tides threatening Corpus Christi’s $1.5 billion tourist industry and millions of fish and aquatic species. In a study by Tominack et al (www.ncbi.nlm.nih.gov/pmc/articles/pmc7500669), “Based on these analyses, the Coastal Bend region of the Texas coast has experienced a significant increase in the frequency of red tide blooms since the mid-1990s. Salinity was positively correlated with red tide occurrence in the Nueces Estuary, and a documented long-term increase in salinity of the Nueces Estuary may be a major factor in the long-term increase in bloom frequency.”
Hotter summer temperatures will lead to more evaporation resulting in increased salinity in the Bay even without the introduction of concentrated brine.
• Kristin Nielsen, Ph.D. University of Texas Marine Science Institute completed a study, “PROPOSED HARBOR ISLAND SALTWATER REVERSE OSMOSIS DESALINATION FACILITY, A Prospective Evaluation of Ecotoxicological Risk”
A recent report identified over 100 toxic contaminates already present in the water and sediment of the Bay. Many of them bioaccumulative in predator fish like redfish, sea trout, black drum and flounder. The study also raises huge questions about the wisdom of the Port’s proposal to dredge the ship channel as it would reintroduce toxic chemicals into the bay that are safely sequestered in the sediment.
Nielsen noted this in her conclusion, “The proposed development project poses a highly uncertain degree of ecotoxicological risk to habitat of high ecological value, …Moreover, aquatic systems adjacent to the discharge site experience remarkably low rates of water exchange/flushing, which is known to facilitate the accumulation of contaminants (including those known to be released in desalination effluents) and is widely recognized as a primary determinant of ecological risk associated with SWRO operations.10, 49, 98, 215 Moreover, facility operations may exacerbate drought conditions, recurrent cycles of hypoxia and hypersalinity that further facilitate COPEC (various toxic chemicals) accumulation and potentiate toxicity of many contaminants to aquatic biota.”
If the site at Harbor Island lacks the flow to remove these contaminants and brine from the Bay, the problem would be much worse at La Quinta Channel or any of the inner harbor sites. The ship channel which dead ends has no inflow except for tidal exchange. It takes approximately 1.5 years for a full water exchange between the ocean and Corpus Christi Bay.
It is way past time for the City Council to get over the “endless water” dream and follow the economics and science. All the data needs to be examined without bias in their decision of what water strategy to pursue. The facts say that desalination is not the most advantageous option at this time. It does not make sense financially without threatening our already overstressed Bay. City Council is not being honest with the citizens if they continue down this path without listening to the scientists whose only interest is protecting the environment from us and us from ourselves.