M.Sc Thesis
M.Sc Student Zaide Michael A Model for Multi-Year Combined Optimal Management of Quantity and Quality in the Israeli National Water Supply System Department of Civil and Environmental Engineering Professor Emeritus Uri Shamir

Abstract

# Israel has entered the desalination era. Development of tools for management of the national water system which consider both quantity and quality of water in the sources, supply system and demand zones are essential. In this work a seasonal multi-year model for management (planning and operation) of both water quantity and quality in the Israeli National Supply System (MYCOIN) has been developed. For the first time, both quantity and quality (salinity) considerations (water sources, supply system and demand zones) are optimized simultaneously for a long term time horizon (10-20 years and more). While the model deals with the operational plan of a given physical supply system, the optimization yields insights with respect to the planning of the system itself, such as:

§          Adequacy of the installed capacity of desalination plants.

§          Adequacy of the removal ratio (outlet salinity) of the desalination plants.

§          The required 'salinity map' in the supply system which is required to meet salinity constraints at consumer nodes and maintain aquifer salinity limits.

§          Installed capacities of production and conveyance facilities.

The solution reports can indicate some of the planning needs ("bottle-necks") by analysis of the results and examination of shadow prices. The objective function and some of the constraints in the model are non-linear. The model is solved by LSGRG (Large Scale Generalized Gradient), an off-the-shelf software that uses EXCEL for model formulation. The results are presented on system schematics and tables for ease of interpretation. A Base Run of an annual model and a number of additional scenarios, and a multi-year run have been conducted. The main conclusions of these runs are:

1.      It is possible to solve jointly by optimization quantity and quality issues.

2.      The model is for optimizing the operation - with planning implications.

3.      It is possible to:

a. Prove whether the stated quality and quantity targets can be met.

b. Indicate and test the means for achieving these targets.

4.      The solution can change - sometimes quite dramatically - when salinity considerations are imposed.

Concerning management of the Israeli National Water Supply System the conclusions are:

1.      In addition to the regular water management policy there is a need to adopt a water quality management policy, expressed by salinity targets at the demand zones and in the natural sources.

2.      The development program should be determined with consideration of the water quality management policy, and may be affected quite substantially by it.