Basis of Design
At the outset we must acknowledge that Messrs. Wolff, Holdren and Ruane have years of experience working closely with Mobley Engineering from their home state of Tennessee, and no doubt understand their technology well, so it is understandable that both the evaluation completed in February 2018 and the modelling completed in August 2018 favors the Mobley design.
Furthermore, based on the fact that Reservoir Environmental Management and Mobley Engineering have been working together on the Lake Carmi project for over a year, one can assume that they have had access to more data and obtained a degree of familiarity with the site that bidders who have only been allowed into the process at this late stage do not have.
This no doubt explains how,in both the February evaluation and August modelling reports, it is recorded that only Mobley Engineering have been able to include costs for factors such as engineering fees, site preparation, an air supply facility, contingencies and other engineering costs that other bidders were not able to do. It appears that Mobley Engineering is in the fortunate position of already having completed the first four Tasks in Table 1.
It is noted that the prescribed location of the on-shore infrastructure favors the Mobley design whereas the ADS system will be forced to incur significant additional airline costs if they are not allowed to use at least two on-shore locations as shown in their design.
Considering these factors and in the light of Perry Thomas, head of the DEC’s lakes programs, statement to the media on 29th July 2018, immediately prior to the publication of the modelling report,that budget had already been approved and the State of Vermont had “settled on” the Mobley Engineering design, we trust that the State of Vermont DEC is acting in good faith, that new respondentsto this RFP will not be prejudiced by the history behind this project, and thatthis RFP is a genuine attempt to find a proven effective solution to eutrophication and hazardous algae blooms at Lake Carmi and not just a process to legitimize a done deal after the fact.
Modelling and Design Report
The models used address only the physical chemistry with respect to a single nutrient; Phosphorus. The model is limited to abstract modelling of the stoichiometric balance of Phosphorus chemistry by correlation with temperature and dissolved oxygen levels and projecting historic data on a single biotic parameter; Chlorophyll α.
Nutrients by definition nourish biota. The profile of the biota is different for every water body and the biotic profile changes dynamically with a number of factors such as environmental conditions, nutrient availability etc. Such changes take place in the short term in accordance with local system conditions “at the margin” and over the longer term. For instance, cyanobacteria become more and more established and dominant within a particular biotic system, thus changing key system attractors that govern system behavior.
There is no cognizance or incorporation of these realities into the Modelling and Design Report.
In more simple terms; nutrients nourish living things. Therefore, the profile of living things such as the phycological balance and types of aquatic weed are critical factors in understanding competitive nutrient uptake insolution design.
If there are no cyanobacteria present, then nutrient uptake by cyanobacteria is zero. As cyanobacteria become more established and assume dominance by outcompeting other living things for those nutrients, their impact on nutrient uptake, nutrient management and the Nutrient Cycle becomes more and more significant. This must be factored into solution design.
We note that there are numerous weed beds shown on the Mobley Engineering design. Factors such as how these weed beds have changed in size, the profile of the types of weeds themselves and the dynamics of sediment accumulation in these weed beds in recent years are all critical to understanding nutrient processing and recycling in the lake. Yet the model does not consider them or their impact on nutrient recycling, let alone attempt to factor them into solution design.
These changes are subject to, and mediated by, a number of dynamic feedback loops, meaning that linear mathematical projection based on historic single factor correlations is not applicable.
In a dynamic complex adaptive system, the past is not a good predictor of the future. If the lake has exhibited a stable, consistent pattern of nutrient uptake over the past several years as reflected in the consistent numbers and types of algae and cyanobacteria present, then projecting historic data into the future may be a feasible option. However, if eutrophication and toxic algae blooms have exacerbated during that time,and the lake is now “in crisis”, then it is illogical to use modelling of the past to predict future behavior of the lake. Such system changes typically follow asymptotic trajectories which the models do not use.
Cyanobacteria are particularly adept at outcompeting competitors for the nutrient Nitrogen. The physical chemistry of Nitrogen in eutrophic water bodies is even more complicated than that of Phosphorus and is particularly relevant to eliminating cyanobacteria. Yet the modelling does not consider this.
The only parameter considered in the modelling which relates to the biotic profile is Chlorophyll α. This parameter is used as a proxy measurement of green algae and therefore when used in isolation, is of limited value when developing a solution design to eliminate cyanobacteria. There is no data provided on total phycological or cyanobacteria levels, the phycological balance, or changes in the phycological balance as eutrophication has progressed and cyanobacteria have reportedly become more dominant.
Examination of our Bowling Green Reservoir case study will reveal the importance of monitoring and managing the phycological profile when designing and delivering a solution to toxic cyanobacteria blooms and demonstrate that solution design must factor this into account and active bio-interventions must be incorporated into the solution design.
The modelling and the general approach adopted is one dimensional in that it considers Phosphorus as the only relevant nutrient and the physical chemical aspects of the stoichiometric inorganic chemical balance of Phosphorusas the only critical factor to be modelled.
It is difficult to discern whether this limited understanding of eutrophy, cyanobacteria and nutrient management validated the use of such a myopic modelling and solution design approach, or whether the modelling validated an approach based on a limited one-dimensional understanding of eutrophication, cyanobacteria and nutrient management.
The disconnect between the modelling and design approach adopted, and the dynamic reality of the biotic system that is Lake Carmi is perhaps best elucidated by MarliRupe, who is quoted by the media at the announcement that budget had been approved and the Mobley Engineering design settled on in July 2018 as saying ““It’s hard to see the difference when the algae blooms, but there is a difference when calculating the numbers and phosphorus reduction”.
In other words, “The numbers in our computer model tell us we are reducing phosphorus and cyanobacteria, even if the reality of the algae blooms says otherwise”.
It has been said with regard to eutrophication that “To a man whose only tool is a hammer, every project looks like a game of Whack-a-Mole”.
Defining eutrophication as being only a Phosphorus problem and aeration as the only solution is what condemns remediation programs to become a futile game of symptom “Whack-a-Mole” while the complexity of the root causesis ignored and exacerbated over time.
Notwithstanding this, we trust that for both ourselves and the State of Vermont, the outcome of this RFP process, and the resources committed to it at this late stage, will not prove to be a fruitless and wasteful expenditure.
Our Basis of Design
Clean-Flo designs each water improvement project based on specific details of each water body and the goals established for improvement. Instead of just trying to eliminate a symptom, like algae growth, we are committed to improving the overall body of water long term. This approach leads to elimination or reduction of many symptoms and leads to longer term health of the water body. We want to improve a water body throughout the year instead of focusing only on a causation period. This means that our basis of design will call for operating our program as many months through the year as possible.
The unique characteristics of Lake Carmi are important in our design. As such, a sonar scan will be conducted on the lake as early in the spring as possible. This scan will provide valuable information not only for the final design but for future opportunities to evaluate the effectiveness of our program. What is seen on the surface of the lake is only a part of the story. We want to understand what is happening under the surface. For the purposes of our basis of design we have reviewed the contour map and sampling data available online, as well as the scoping report and modeling data.
Based on our review of all this information, our basis of design will be to oxygenate the entire body of water including the pore water of the sediments. In order to reduce the cause of the algae blooms, our design will recommend system operation for more than the 3 months outlined in the RFP. Our design will also target organic sediment, phosphorus and nitrogen reduction. We will also design for dosing natural enzymes to facilitate the biodegradation of non-living organic sediment on the bottom of the lake.
From a feasibility and cost standpoint, the location outlined in the RFP is not ideal and will have a significant impact on overall project cost. Our goal will be to identify 2 locations; one around the northern half and one around the southern half of the lake in order to locate compressors for the project. We anticipate requiring 500-600 cfm to fully oxygenate the lake to over 4-5 mg/l. Horsepower estimate is 100 hp total. These figures can be firmed up once the sonar scan of the lake is completed.
The scope of work items that have to be completed prior to final approval for equipment and materials ordering for the project, will likely take more time than allocated in the RFP. On a project this size and scope, rushing into the best project solution is not wise. We will strive to meet each deadline in the schedule, but there are pieces of this project such as permitting that are beyond our control. It is also likely that procuring the necessary equipment and supplies will take 6-8 weeks once the design is approved.