Parsons Report
Executive Summary

1.1          Introduction

Parsons was retained by the Salton Sea Authority to perform an independent technical review and critique the Phase 1 alternatives described in the Draft Salton Sea Restoration Project Environmental Impact Statement/Environmental Impact Report (EIS/EIR).  Fatal flaws, as well as possible refinements, in the alternatives were to be identified.  Possible Phase 2 actions/concepts were to be briefly evaluated, primarily from a cost-effectiveness point of view.  In addition, other possible salinity and elevation control actions were to be identified and suggestions for further analysis were to be made. 

URS Greiner Woodward Clyde, Jones & Stokes, and John A. Pyles were key members of a team assembled by Parsons to conduct the above analysis.

Generally, URS performed a review of the in-Sea dike design proposed in the Salton Sea Restoration Project January 2000 Draft Alternatives Appraisal Report and the costs of the various concepts and alternatives.  Based on that review, refinements were suggested to reduce seismic risk and cost.  Comments regarding construction methods for in-Sea dikes were also provided.

Jones & Stokes evaluated the Bureau's water and salt accounting model for suitability in determining if alternatives can effectively meet the salinity and elevation goals established for the restoration project. They also used the model to review the effectiveness of the Draft EIS/EIR alternatives and to assist in identifying concepts for review and evaluation.

Mr. John A. Pyles, a retired Cargill Salt employee, focused primarily on the solar salt removal (and disposal) concepts proposed in the Draft Appraisal Report and provided an in-sight into the chemical properties of Salton Sea water and their effect on salt removal and disposal.  Building upon the ideas of the Salton Sea Authority Executive Director, he developed a concept for removal of salt in a series of solar evaporation ponds and disposal in separate crystallizer ponds.

Parsons coordinated the work and kept the team focused on the big picture.  In addition, Parsons suggested refinements to the alternatives, developed alternatives and concepts for further evaluation, and performed much of the cost-effectiveness analysis.

This study focused on the technical and engineering aspects of the water and salt management alternatives described in the Draft EIS/EIR and Draft Appraisal Report.  No evaluation of the potential environmental effects of the Draft EIS/EIR alternatives or of the suggested modifications to the Draft EIS/EIR alternatives was performed.  It was assumed that the environmental effects of the recommendations contained in this report will be addressed as the preferred restoration project evolves.

1.2          Approach

The Parsons Team met with the Salton Sea Authority in La Quinta, California and with the Bureau of Reclamation in Denver, Colorado to gather background, key documents, and other supporting information.  In addition, members of the Parsons Team toured the Salton Sea to gain additional understanding and information. 

The Draft Appraisal Report and the Draft EIS/EIR were used extensively in our evaluation. Other supporting information was also used in our analysis.  Practical experience in building in-Sea dikes and other facilities, water and salt modeling, salt making, and similar projects was melded into our work.

The Team's experience with designing and constructing in-Sea dikes, dams, and other facilities combined with the perspective contributed by Mr. John A. Pyles led to the development of concepts for using solar evaporation ponds in a more effective manner for salt removal and disposal.

The Bureau provided a copy of its water and salt accounting model to the Team.  The model was reviewed for suitability and used to analyze the effectiveness of the Draft EIS/EIR alternatives.  The model also helped the Team to understand the interrelationship between salinity changes and elevation changes more easily.

1.3          Conclusions and Recommendations

The Salton Sea Authority and the Bureau of Reclamation with input and guidance from the Salton Sea Authority Board and Technical Advisory Committee and the Salton Sea Science Subcommittee have devoted significant time and effort to the Salton Sea Restoration Project and produced a considerable amount of information. The information gathered, the documents produced, and the public participation process has provided the foundation for completion of appraisal level studies and initiation of more detailed evaluations that can lead to selection of a preferred project for the Final EIS/EIR.

Our more significant conclusions and recommendations, based on a review and analysis of available data, are listed below. These conclusions and recommendations are discussed in the body of the report.  Other less significant conclusions and recommendations are contained in the report itself.

1.3.1       Conclusions

The water and salinity accounting model and the assumptions used in the model provide a suitable tool for evaluating the effectiveness of proposed alternatives for meeting salinity and elevation goals established for the Salton Sea.

Each of the Phase 1 Draft EIS/EIR alternatives can meet the elevation and salinity goals within 40 years of implementation.

If the inflows to the Sea are ultimately reduced to 0.8 million acre-feet per year (MAF/yr.) additional replacement inflows and/or displacement facilities will be required to meet the current salinity and elevation goals.

The south pond would remove essentially the same surface area from the Salton Sea as the displacement dike for about one-half the estimated cost (about $195 million versus $450 million).

The in-Sea north and south ponds and the displacement dike (as currently designed for the proposed operation) are very vulnerable to damage or failure due to a major seismic event.

If the north and south in-Sea ponds (and the displacement dike) are constructed as proposed, they should be operated with water on both sides of the dike to reduce the vulnerability to seismic events. To reduce consequences of possible breaching, water on the pond side should be slightly lower than the Sea.

A displacement dike can be designed and constructed to be dry on one side.  A conceptual design is provided in this report.

Low in-Sea dikes are considerably less costly than tall in-Sea dikes and less vulnerable to earthquakes.  For example, a 17-foot high dike would cost about one-third as much per linear foot as a 35-foot high dike.

Onshore dikes would cost considerably less per linear foot than in-Sea dikes, assuming the same height and good foundation conditions.

A series of solar evaporation ponds are more effective for evaporating Salton Sea water and removing salt than a single deep pond.

The single deep ponds, if constructed, should be operated as the first solar evaporation pond in a series with separate salt disposal ponds and/or an EES to increase the life expectancy and efficiency of the ponds.

Enhanced Evaporation Systems (EES) accelerate evaporation, but are not currently used by the salt industry to make salt because the annual operation, maintenance and replacement costs are much higher than for solar evaporation ponds.

Use of Colorado River flood flows (if they are available) and Central Arizona Salinity Interceptor (CASI) water (if it becomes available) are much more cost-effective than other methods of obtaining replacement inflows or reducing the amount of inflow needed to stabilize the elevation of the Sea.

Exporting Sea water to the Pacific Ocean or the Gulf of California is an effective but prohibitively expensive way to remove salt from the Sea.

Importing Pacific Ocean or Gulf of California water to the Sea is not an effective way to reduce or control the Sea’s salinity or water elevation.  The salt content of the Pacific Ocean and/or the Gulf of California water is too high.

Higher salinity and lower elevation goals would reduce the size and cost of the actions or concepts needed to achieve and maintain salinity and elevation goals.

1.3.2       Recommendations

An evaluation of alternative(s) using a series of solar evaporation (onshore and/or in-Sea) ponds with onshore salt disposal and bittern disposal ponds should be made.

Because of construction cost, priority in evaluation should be given to onshore solar evaporation ponds, followed by shallow in-Sea and then deep in-Sea ponds.

Consideration should be given to potential displacement benefits from in-Sea ponds and to using deeper ponds to dispose of bittern while using the surface of the ponds to evaporate Sea water.

If insufficient land is available and/or solar evaporation ponds cannot be constructed for a reasonable cost, consideration should be given to using an EES in conjunction with solar evaporation ponds.

Borings should be performed along the alignment of all in-Sea dikes selected for detailed analysis to determine foundation material properties and to verify and refine costing assumptions.

A preliminary earthquake response evaluation should be performed on the proposed in-Sea dike designs to analyze and predict potential deformation modes.

Soil percolation data should be obtained for those sites where onshore ponds may be constructed.  Leakage will affect the amount of pond area needed to achieve a certain rate of salt removal.

A series of small solar evaporation test ponds should be constructed and operated at the Salton Sea to obtain data for preliminary sizing and development of the solar evaporation pond concepts.

The evaporation rate of Salton Sea water is needed so that the size of the evaporation ponds can be refined.

The volume of salt produced and its density are needed so that the size of salt disposal facilities can be refined.

The characteristics of the bittern are needed to determine if it will dry out and if it can be disposed of in the bottom of deep evaporation ponds without interfering with the evaporation rate.

An evaluation of the cost of dredging the Sea's bottom and depositing the dredged material at the shore for creation of shallow ponds and/or displacement of Sea surface area should be made.

The feasibility and cost-effectiveness of fallowing should be evaluated for maintaining Sea inflows instead of, or until CASI water is available.

EES should be pilot tested to obtain better annual cost data and confirm area requirements and evaporation rates.  An EES demonstration plant should be constructed and operated for at least a year to refine pilot plant data for final design if the EES is part of the project alternative.

A review of the Sea's elevation and salinity goals should also take place before completion of the Final EIS/EIR.  A salinity range of 35 to 40 ppt and an elevation range of -230 to -235 feet MSL was previously established; however, a target elevation of -230 feet was recently established.  If the inflow to the Sea decreases, a lower target elevation would require smaller quantities of replacement inflows and/or smaller displacement facilities.

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