Alex Horne Associates

Review of Environmental Impact Statement - Lake Source cooling Project: Cornell University


I have reviewed the entire document "Environmental Impact Statement - Lake Source Cooling Project: Cornell University". In addition I have used various other publicly available publications and texts on Lake Cayuga and the other New York Finger Lakes. The "Environmental Impact Statement - Lake Source Cooling Project: Cornell University" is intended to cover all the effects of a large-scale cooling water extraction and return from Cayuga Lake, one of the New York Finger Lakes. The EIR covers many aspects of the project but I will restrict my comments to the area of the effects of the proposed cooling system on the lake ecosystem. The effects of the LSC on the limnology of Cayuga Lake are divided into those affecting the physical, chemical, and biological aspects. Most attention in the EIR was paid to the physical effect, no concern was paid to chemical toxicity and pipe fouling. Biostimulation models and mysid shrimp were the main biological concerns of the EIR. In most cases, a sufficiently complete data set and discussions were available in the EIR for me to draw conclusions without the need for much additional information.

My qualifications as a reviewer for this project are that I have carried out research on the effects of nutrients on aquatic ecosystems on all five continents beginning in 1964. I have been a professor of Ecological Engineering teaching and researching lakes and other water bodies since 1971 at the University of California at Berkeley (see attached resume). I have written the best selling undergraduate textbook on limnology (the study of lakes) and have published 178 research papers and articles in the fields of pure and applied limnology and oceanography. I have been involved in the writing and research needed for dozens of EIRs in the US and elsewhere. In terms of cooling systems, I teach thermal pollution as part of my courses and have spent several years carrying out research on all the effects of very large ocean cooling systems for the Federal Ocean Thermal Energy Conservation (OTEC) Program. The OTEC projects were almost identical to the proposed LSC project in that both involved bringing up large volumes of nutrient-rich deep water in large pipes and releasing it on the surface. Over the years of our research in the 1980s we found that major environmental concerns were the biostimulation caused by the upwelled nutrients and the incidental toxicity produced by pipe cleaning and leaks in the various cooling fluid exchange systems.

Critique of the EIR

Eutrophication Potential of the LSC Project

Probably the most important environmental effect of the upwelling of cool deep and nutrient rich water is the threat of eutrophication. Lakes are classified into productive (eutrophic), unproductive (oligotrophic), or in-between (mesotrophic). In general, oligotrophic lakes are the most preferred by human users and Cayuga Lake was probably completely oligotrophic 200 years ago. Eutrophication is the process whereby addition of inorganic nutrients to a lake causes an increase in algae. Undesirable scums of blue-green (cyanobacteria) are characteristic of eutrophic lakes as are decreases in water clarity. Blue-green algae produce many other undesirable effects including taste and odor in drinking water supplies as well as organic chemicals that are highly toxic to wildlife and humans alike.

Most of Cayuga Lake contains clear unpolluted water free from large growths of algae. The southern end of the lake is no longer in this condition and has no ability to accommodate further pollution. The southernmost portion of Cayuga Lake is already technically either eutrophic or mesotrophic depending on the indices used (Table 1). The proposed LSC outfall is in the most degraded area of Cayuga Lake which is currently in a very ecological delicate balance and not likely to withstand increases in nutrients without exacerbating water quality problems.

Table 1. Trophic state of Cayuga Lake in the southern part near the intended LSC outfall. This section of the lake is either over or very close to the mesotrophic-eutrophic border and will not accommodate the LSC nutrient addition without becoming more eutrophic. Most water uses are incompatible with a eutrophic lake, which is thus undesirable. Cayuga Lake data is from the EIR, other values are typical of those found in the published literature and were formed by averaging many published values. TP = total phosphorous, TN = total nitrogen, Chl a = chlorophyll a, the green pigment used to approximate algal biomass. Secchi depth is a measurement of water clarity that indicates how deep in the water column a white disc can be seen.

Near proposed
Sta # P2
TP (µg/L) 24-31 42 20 31.5
TN (µg/L) 1,200 1875 753
Chl a (µg/L) 6.8-8.9 19.4 6.9 7.9
Secchi depth (m) 1.5-1.9 m 1.4 3.4 2.6

Current violations of the NYSDEC guidelines for TP in the LSC discharge area. The area of Cayuga Lake close to the proposed outfall is already above the guideline of 20 µg/L for TP proposed by the State DEC (Table 1). Average summer values for 1994-96 TP of 24-30 µg/L are given in the EIR (Table 2.3.3-14). Unaccountably the EIR considers 24-30 µg/L to be less than this guideline of 20 µg/L. The EIR states, "data indicate that southern Cayuga Lake currently meets the ambient water quality guidance value for TP in ponded waters since the summer average concentration is consistently below 20 µg/L)." (p 2.3.3-21). A similar statement "Note that Cayuga Lake meets the NYSDEC TP guidance value or 20 µg/L." (p. 2.3.3-5). The only explanation for the discrepancy is that the EIR considers the entire lake or at least all of the southern lake as a dilution field for its waste effluent, which is neither realistic nor appropriate. The actual discharge will take place in a region of the lake where the guidance value was already consistently exceeded by an average of 34% (range 19 - 54%, summer averages 1994-96, taken from EIR table 2.3.3-14). The misuse of the dilution field is discussed below. The reliance on TP rather than a more robust indicator such as chlorophyll a or algal species is also discussed below.

EIR's Over-Reliance on Dilution to Reduce Eutrophication Effects

The EIR's conclusion that there will be no significant effect on the physical, chemical and biological aspects of the Lake Cayuga depends to a large part on dilution of the LSC effluent with large volumes of other, cleaner water. Another unsupported assumption is that the discharge of bioavailable phosphorus will be physically diluted to background levels and thus have no effect.

Choice of area for dilution of the effluent plume. In terms of physical dilution the EIR findings of no significant effect depends entirely on the volume or area of lake chosen to dilute the effluent. The EIR chooses the entire lake area south of Myers Point as the boundary for dilution water (Chap 2, p. 2.3.3-25). However, based on the EIR model of the effluent plume, the area chosen could equally well be the area south of Portland Point and half way across the lake. If this alternative were used, the plume of increased phosphorus would have five times less dilution and the effect would become significant.

My choice of a smaller volume relative to that shown in the EIR is not incompatible with the lake's physical limnology. For example, the EIR model of the discharge shows a long plume of nutrient-polluted water stretching for over four miles along the eastern shore of the lake (Fig. 2.3.3-8D). The water in the plume is obviously not mixing equally throughout the entire southern basin of the lake south of Myers Point as stated in the EIR calculation of dilution (Chap 2, p. 2.3.3-25). Thus the EIR's use of larger volumes for dilution of the added phosphorus is not appropriate to calculate the percentage effect of discharge from the LSC. The higher percentage 'of added phosphorus with a smaller and more realistic plume indicates that the effect of the nutrient additions are significant, not insignificant as stated in both the EIR and restated in the Response to Comments made During Adequacy Review (section 1.3.3, Conservation Board, Environmental Review Committee). The increases in TP should be mitigated.

Appropriate time scales for calculation of dilution fields. The correct time scale is important for the calculation of the dilution field. Eventually, most of the discharge will mix through most of the volume of the entire Cayuga Lake. Neither the author's of the EIR nor consider the entire lake the appropriate volume for nutrient dilution. The EIR chooses the entire southern section; my own choice would be the plume bounded by some dilution such as that shown in the EIR fig 2.3.3-8D. In this figure, the boundary of an increase of 0.1 µg/L TP is shown as a plume extending for over four miles along the eastern boundary. The time taken for this plume to form is not shown but it is the order of hours or days not months.

Phytoplankton takes up phosphorus in a few minutes or hours and can store it for later use in special cell inclusions called poly-phosphate granules. Up to 20 times the amount needed for growth can be stored in this way which means that algae need only a short exposure to take up the phosphorus for later growth. Thus the dilution of phosphate assumed be the LSC EIR model is not appropriate. The phosphorus will not be diluted to insignificant levels. It will be mostly taken up quickly by algae and use for growth downstream and in other areas where the algae accumulate.

EIR's Underestimate of Effects of Phosphorus on Lake Eutrophication

The main impacts of the LSC are that in summer, relatively high nutrient content water will be brought up from the hypolimnion and released into shallow, nutrient-depleted epilimnion water. Chapter 2 in the EIR discusses the effect of the phosphorus component of hypolimnion deep water on algal growth and other algal-related effects in the epilimnion. My budget does not allow me scope to check the complex model calculations, references or assumptions made in the EIR with regard to algal biostimulation. However, that is not needed at this stage as the author's of the EIR clearly state concentrations, assumptions, and methods used to estimate the magnitude of biostimulation. The concern for the lake is that an increase in TP of 3-7% is not considered significant by the EIR's authors. There is a case to the contrary to be made that the effect on eutrophication will in fact be very significant and will produce significant side effects.

Postulate in the EIR. The EIR makes the argument that a 3-7% increase in TP per month (p. 2.3.3-17) is a small change and would be undetectable against the natural fluctuations in nutrients expected in such a large lake.


  1. First if the argument that a small monthly percentage increase is insignificant was used, every waste treatment plant around the lake would be able to expand with no increased treatment so long as each increment was less than say 10%. The current trend in enclosed water bodies is to use a total maximum daily load (TMDL). Thus the increase from the LSC would increase the internal TMDL on the lake, which is already in critical condition. Any effects of increases in TMDL should be mitigated.

  2. Second. the percentage is only as small as 3-7% because of the very large contribution of soluble phosphate from the City of Ithaca waste treatment plant and other smaller plants. If these were treated to the maximum feasible level (50 µg/L TP), the contribution of the LSC would increase to over 30% in normal years and over 50% in dry years. These presumably would be considered significant effects. It is reasonable for a project with a 20-40 years or more lifetime that the expected improvements in local wastewater treatment would not be negated by the LSC nutrient additions to the shallow water area.

  3. The eutrophication argument proposed in #2 is not trivial. The health of Cayuga Lake with regard to eutrophication is not good. The lake is already considerably polluted with nitrate (concentrations ~1,200 µg/L). As recently as 1994 TP concentrations in the surface water in the south section were over 30 µg/L and Secchi depths were well below the warning level of 2m. These approach or encompass eutrophic conditions that are not desirable in a drinking water and water contact lake.

  4. The increase is small only when considered over a large part of the lake. In the several miles the plume is likely to affect the change is much larger (see early discussion).

Lack of More Robust Indicators of Eutrophication Such as Chlorophyll and Algae Type

Chlorophyll a increases due to the discharge. Phosphorus is a cause of impairment of lake designated uses but, by itself, is not a problem. The use of TP as an indicator is that it only indirectly indicates the actual impairment of the lake. Two of the most likely problems that will occur as the LSC project causes lake eutrophication are increases in total algae and the occurrence or increase in nuisance blue-green algae. The first item is lightly covered in the EIR where a calculated prediction of chlorophyll is made assuming all TP produced by the LSC project were converted to algae (p. 2.3.3-24). This is a conservative assumption but the EIR uses a TP:Chl a ratio of 1:1 (p. 2.3.3-24) and quotes a literature range of 0.5 - 2.0. This ratio was not measured as part of the EIR and so there is no good reason to suppose that the extreme part of the ratio could apply in the southern end of Cayuga Lake. If this were so, the amount of algae produced per TP would double.

In addition, a very large dilution volume of the entire southern basin (20 million m3) was used to show a small overall effect despite the fact that the LSC CORMIX2 model predicts that the effect would occur in a very much smaller area. The use of the area of the plume indicated in Fig. 2.3.3-6D would show an increase many times higher than that predicted in the EIR. I do not have the CORMIX2 model to give me the most precise figures but using the same assumption as the EIR for dilution (p. 2.3.3.-24), I calculate that the chlorophyll would be spread over about 5 km2 at most. Thus the actual chlorophyll would be about four times that calculated in the EIR. The EIR indicates an average of 2.5 µg/L cumulative increase (range 1.25-5 µg/L) for June-October using the entire southern lake epilimnion (20 million m3) as a dilution zone (p. 2.3.3-25). If the limit of the range of TP:chl a used in the EIR were used, these values could increase chlorophyll a to 10 µg/L cumulative for the summer season. Using the more conservative dilution indicated above the chlorophyll would increase a further four times to 40 µg/L. This is more than five times the average found for the discharge area in the 1994-96 summer monitoring.

Likelihood Of Increased Nuisance Blue-Green Algae (Cyanobacteria) Blooms Due to Discharge

Blue-green algae, also called cyanobacteria based on cellular structure, are perhaps the worst symptoms of eutrophication. In general, as the lake becomes more eutrophic blue-green algae come to dominate the water. That means that most of the additional eutrophication, as will be produced by the LSC discharge, will be manifest as blue-green algae. There are already blue-green algae in the lake and they have increased in historical times as local sources add nutrients. In the area of concern near the proposed LSC discharge, there are reports of scums of blue-green algae already forming an aesthetic nuisance. The LSC project cannot help but make the situation worse.

The amount of new blue-green algae in the several square kilometers of affected water may reach 40 µg/L as show above. By any standards that would be a severe nuisance and could result in taste and odor problems in drinking water, dead pets and livestock that drank the water, filter blockage, and production of organic carbon that would require coagulation. Blue-green algae produce several odiferous compounds, particularly geosmin and MIB whose removal from drinking water supply systems would require investment of millions of dollars. Blue-green algae also produce some of the most virulent toxins known, especially a liver toxin (micocystin) and a saxitoxin-like neurotoxin. These compounds are present in half of all blue-green algae ever sampled and kill thousands of livestock every year in reservoirs and lakes that have become eutrophic. In several countries including Australia, UK and Canada, restriction on water use for drinking and water contact have been made based on the amount of algae present or its toxin. The amount of blue-green algae that could be produced by the 4-mile long LCS plume would exceed some of these standards.

Also possible with such dense blooms is a series of luridly patterned dying blooms that would be a visual nuisance and could create such an odor that they would clear the beaches and houses for 300 m back from the shoreline. Hydrogen sulfide and even more odiferous mercaptans (skunk-like odors) are produced by dense accumulations of blue-green algae that float to the surface and become trapped in small bays and coves. Since the plume of affected water hugs the east shoreline these effects are even more likely. None of these possibilities was discussed or mitigated in the EIR.

Horizontal Motion of Blue-Green Algae in a Manner Not Predicted by the EIR Math Model

The EIR totally neglects the ability of blue-green algae to move in a direction away from the prevailing current. Unlike most other algae, blue-green can control their buoyancy and float on or near the surface. In this position they can migrate several kilometers per day in a direction that is not that of the prevailing water current. The motion is achieved mostly on calm days when the prevailing wind moves the very surface waters. Hydrodynamic mass balance is achieved since the deeper water (all but the top few cm) continues to move in the direction expected by the model

In terms of a nuisance, the main effect of the LSC project will occur when the algae are wind-blown back into the shallow area near the discharge, not carried out willy-nilly with the plume. The resulting accumulation of blue-green algae could accumulate into blooms that would turn the surface of areas of hundreds of square meters of the lake bright green overnight.

EIR Omits Any Corroborating Experiment Evidence to Support the CORMIX2 Math Model

Complex lake models such as CORMIX2 are excellent tools for determining relative differences between project options, but are less useful in providing reliable absolute numbers and at predicting specific biological responses. This is recognized in many kinds of aquatic studies. Therefore, in my experience it is normal practice to confirm the model predictions using actual experimental lake studies. For example, even the simple chlorophyll a - phosphorous model quoted in the EIR was extensively tested experimentally in laboratory microcosms, lake mesocosms, and whole lake experiments. Similarly, the LSC discharge could easily be tested by taking actual lake organisms and adding the amount of nutrients predicted to be produced by the discharge at a range of realistic dilutions. The resulting chlorophyll a and species produced would confirm or deny the model assumptions that are based on very general limnological principles.

I have been involved in many projects where the effect of nutrients on a water body was of prime concern. These included the effects of cooling water discharged at the surface, addition of various kinds and dilutions of wastewater, and effects of toxicants. In almost all of these cases the math models were tested and modified using laboratory and field experiments. In particular, mesocosm-scale enclosures were set up in the lake, reservoir, river, estuary, wetland, or ocean to give a more realistic determination of the effects of the discharges. Only in the very preliminary phases of any project should the EIR rely on a math model to predict actual effects.

Incorrect Use of Nitrogen Data and N:P Ratios in the EIR

The LSC will bring up nitrate and some ammonia as well as phosphorus. In the EIR it states that there is already ample nitrate in the region of the discharge so no harm will come from adding more. The EIR neglects to point out the lake is already polluted with nitrate so that any additional phosphorus will produce the maximum amount of algae. The high nitrate in Cayuga Lake is no doubt due to the long-term effects of wastewater pollution, forest clearances over the past 300 years, and agricultural nitrate fertilizer addition. The correct interpretation in the EIR with regard to high nitrate levels should be that the area of discharge is very sensitive to phosphate pollution.

The EIR considers that the high nitrate concentrations will inhibit the growth of blue-green algae due to the maintenance of a low N:P ratio even with the current LSC discharge of 20 µg/L (pp. 2.3.3-26 to 27). Given a concentration of nitrate of about 1,200 to 1,400 µg/L as N in the discharge plume and about 5-20 µg/L TP, (ratio > 100) this assumption seems correct. However, the more realistic concern is that a high N:P ratio only prevents nitrogen fixation. All blue-green algae can grow well on nitrates as well as nitrogen gas and some of the major nuisance species such as Microcystis, do not fix nitrogen.

A high N:P ratio does not protect against blue-green algae at all. High nitrate or ammonia inhibits nitrogen fixation but does not prevent blue-green growth. The EIR should thus have paid proper attention to the undesirable effects of blue-green algae mentioned above.

Toxicity and Effects of Cleaning the Pipes of Fouling Organisms

In the EIR it is proposed to clean fouling organisms from inside the intake and outlet pipes using mechanical means. The pipes have also been oversized to allow for some growth. The EIR does not give any alternative if this method fails. My own experience with fouling organisms is that they form easily and are difficult to remove.

If the mechanical cleaning method works it will produce a very large amount of battered animal and plant tissue that must be disposed of somewhere. If disposal of the dead fouling organisms is to be in the lake, then the effect of this decaying matter must be addressed. If the mechanical method does not work, then the effect of a more conventional cleaning method such as chlorine must be addressed. In situ dechlorination is possible but is not discussed.

No mention in the EIR is made of the toxic effects of the main cooling fluid and its slimicides or heavy metals. In my experience there will always be leaks between the main once-through cooling water (lake water) and the recirculated cooling water (the refrigerant that will pass through the campus system. Many buildings will have some cooling pipes made of copper and this will be dissolved into the cooling water. To reduce fouling in the campus system some slimicide may be used. Even plastic piping releases toxic compounds such as mercury and organic compounds to the water passing through. There is no provision in the EIR to test for such leaks in a methodical way and ensure that they are dealt with promptly.

Effect of Waste Heat

The author's of the EIR have been mostly cautious and conservative in their calculations of the effect of thermal pollution on Cayuga Lake. In terms of physical limnology, the EIR is correct in assuming that the annual effect of the added heat will be small in comparison with sunlight on a daily or seasonal basis in terms of whole-lake effects. Similarly, the effects in summer will be small compared with the daily heat input from sunlight and the daily loss from evaporative cooling.

However, the same situation will not prevail in winter when there is normally ice cover in the shallow southern section near the discharge pipe. In winter the LSC project will have an effect, especially if smaller spatial and temporal intervals were employed. A characteristic effect of winter discharges of waste heat on lakes is the reduction in the period of ice cover. This item is not covered in the EIR that only states that ice cover is not complete on the entire lake. As in other parts of the EIR the local effects of the LSC project are neglected and the project is viewed more from a lake-wide perspective. Such a large-scale perspective is not appropriate for thermal pollution using a near surface discharge.

It is possible that there is no negative effect from an increased open water area near the discharge but there are several typical effects of thermal pollution in shallow waters in winter. One common problem is the fish become acclimated to the warmer water in winter and when emergency or planned maintenance shutdowns occur the fish experience rapid thermal shock and die in large numbers. A second effect is the shifting of the breeding season of some aquatic organisms that key breeding to temperature cycles. In many thermal plant effluents these organisms hatch out earlier due to the warm water. However, since their food is keyed to sunlight, which has not increased, there is no food and thus the year's young animals die. These common effects of waste heat are not addressed or mitigated in the EIR.


Prepared by the Cayuga Lake Defense Fund (CLDF).
For more information, Call: (607) 275-9054 or 272-7914 or email

CLDF 1998