1. Prepared by Musab O. JayyousiOsama H. Shaheen Dr. Mohammad N. Almasri Modeling and Management of the Stormwater of the Old City of Nablus Nablus – Palestine May 2010

2. INTRODUCTION  Stormwater collection have many impacts on civilization (environmental, economical, social).  Stormwater is of concern for two main issues:  The volume and timing of runoff water (flood control and water supplies)  The potential contaminants that the water is carrying.

3. INTRODUCTION  This project is concerned with stormwater collection system of the Old City of Nablus.

4. INTRODUCTION

5. OBJECTIVES  Hydraulically analyze the Old City stormwater collection system  Determine the causes of major problems, critical section and the minimum rainfall intensity where the problem start to show up.

6. D ESCRIPTION OF THE STUDY AREA  Stormwater collection system is affected by the location of the Old City beneath mount Gerizim and its population.  The inefficiency of the stormwater collection system due to :  Large amount of stormwater  Maintenance and cleaning

7. D ESCRIPTION OF THE STUDY AREA  Old design  Lack of pubic awareness

8. Data Collection Field Work Model Development Evaluation the Results Scenarios METHODOLOGY Data Processing

9. D ATA COLLECTION  Collect Maps  Study area and reconnaissance  Dimensions of the stormwater collection system elements

10. F IELD WORK  GPS  Taking pictures  Water flow direction  Interview  Determine the missing data

11. D ATA PROCESSING  Identification of water flow direction on maps and determine catchment areas for each catch basin  Determine IDF curves

12. M ODEL DEVELOPMENT (S TORM CAD)  StormCAD was used in this study to develop the hydraulic model.  It can provide comprehensive modeling for the design and analysis of storm sewer system.  The general output of the StormCAD presenting the results including (reports, flex tables, profiles, element annotation and color coding)

13. M ODEL DEVELOPMENT  Define the dimension and the type of the pipes.  Define the catch basin by entering the dimension and its type, then insert elevation of catch basins.  Insert all elements of network on StormCAD software and make it resemble the existing system as close as possible to reality.

14. RESULTS  The result of the model represent sections and elements that were expected to have problems, and define its type:

15. RESULTS  Pipe overtopping

16. RESULTS  Catch basin is flooded

17. SCENARIOS  We suggested some alternative and interpret it into inputs and select the best alternatives. # Description Effectiveness in solving the problems Working area Scenario “1” The purpose of this scenario is to prevent the huge amount of Mount Gerizim stormwater from entering the Old City, and to convert it to another network system.  Conduit overtopping (Low)  Catch basin is flooded ( High) Scenario “2” The main idea of this scenario is to change specific the pipelines with larger ones in order to increase its capacity.  Conduit overtopping (High)  Catch basin is flooded (Low) Scenario “3” This scenario based on a combination between the first and the second scenarios, to overcome the existing problem.  Conduit overtopping (High)  Catch basin is flooded (High)

19. SCENARIOS Before and after scenario 3 Before After

20. THE EXISTING DESIGN Before and after scenario 3 Before After

21. A PPLYING A STORM EVENT ON SCENARIO 3  The strongest storm event in 2009-2010 was distributed on 3 days with very high rain intensity. DataRain depth (mm) 25\2\201063.3 26\2\2010 74.6 27\2\201012.7

22. A PPLYING A STORM EVENT ON SCENARIO 3

23. CONCLUSIONS  The problem that was described starts to show up clearly in some sections of the system at rain intensity of 25 mm/hr, and expands to appear in most parts of the network at rain intensity of 40 mm/hr.  The use of pipelines with diameters of 12 inches is not effective in combined stormwater and sewer collection system.  Time of concentration (tc) and rational coefficients (C) have a significant impact on the drainage of stormwater.  The location of the catch basin affects the efficiency of stormwater collection

24. RECOMMENDATIONS  Exchange the diameter of the pipes the network that was mentioned in Chapter 6 from 12 inches to 20 inches.  Establish a drainage system at the southern entrance “Al- aqaba stairway” and Adjaj stairway "in order to divert stormwater which come from the mountain before entering the Old City.  Make a full maintenance for all network elements, and change the damaged ones, and determine the times of periodic maintenance, especially before winter.  Impose penalties on those dispose of solid wastes in the catch basins in the Old City.

25. WITH OUR REGARDS