טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentGilboa Ben-David Yael
SubjectAssessing the Effects of Anthropogenic Activities on Water
Quality in Lake Kinneret Using an Integrated
Modelling System
DepartmentDepartment of Civil and Environmental Engineering
Supervisors Professor Eran Friedler
Dr. Gideon Gal
Full Thesis textFull thesis text - English Version


Abstract

The goal of this research was to develop quantitative means for advanced integration between lakes and watershed management tools that will allow conservation of in-lake water quality based on sustainability criteria, using Lake Kinneret as a case study. Therefore three quantitative models were integrated into one system: a modified watershed model (AVGWLF-HYMKE-MF), a lake ecosystem model (DYCD) and a water quality quantification system.


The watershed model, AVGWLF, which, was not fully calibrated in the past, was calibrated and verified in this study. To accurately simulate stream flows, as well as sediment and nutrient loads, two external tools were linked to AVGWLF: the HYMKE model for predicting daily flows of the Snir River and springs which were not simulated by the AVGWLF model; and a newly-developed multiplication factor algorithm (MF) for adjusting sediment and nutrient loads.


The second part of the research focused on developing and establishing the interfaces between the three tools. Two methods were used; converting the monthly loads into daily values by creating monthly average (constant) values and the use of empirical published relationships to combine between the two different models: Missing parameters were expressed by using other variables, based on published empirical equations that were calibrated using three different calibration methods: Linear and nonlinear regression, and Genetic Algorithm.


In the third part the developed integrated modeling approach was expanded for defining acceptable levels of management measures that will allow sustainable management of water quality in a lake ecosystem. Here, a three dimensional solution space was created. This solution space defines all acceptable combinations of N, P loads and water levels, providing a tool for defining the extent of measures that will allow lake ecosystem sustainability. This approach is unique, and the first example of implementation of a management tool that integrates nutrient loads and water levels through a combined water quality index (CWQI).


The final part used the integrated modeling system for quantifying the impact of watershed management on the Lake Kinneret ecosystem. Changes in watershed management were examined and quantified by evaluating the impact of a number of management scenarios on the lake downstream.


The study provides new quantitative tools for assessment of the efficiency of water resources, land-use and lake operation management in the Lake Kinneret watershed as a case study. These tools offer the ability to rigorously examine various watershed-lake management strategies enabling maintenance of robust lake ecosystems overtime under the varying anthropogenic pressures.