1. Hydrological Assessment and Hydraulic Design of Culverts along Nablus-Tulkarm Road  

2. Prepared by: Sulyman Khraishe Madhat Z
Prepared by: Sulyman Khraishe Madhat Z. Yassin Ahmad Ashqar Sabri Thaher Under the supervision of: Dr. Sameer Shadeed

3. Presentation Outline Introduction Study Area Hydrologic Modeling
Hydraulic analysis and design
Results and recommendations

4. Introduction

5. Objectives Estimate peak flows at each culvert.
Do the hydraulic design of the culverts.
Evaluating the existed culverts by comparison with results we got.

6. Significance of the work
Tulkarm-Nablus Main road is one of the important roads in West Bank where WadiAz-Zeimar crosses it many time.
an extreme rainstorm event occurred in Palestine in 2013, three persons passed away and vast damages happened for buildings, streets and other infrastructures.

7. Significance of the work
General assessment indicates that the main reason behind such flood consequences is that:
the existing culverts were failed to handle the peak flood flow.
This can be attributed either to improper size of culverts or to the dumping of garbage in the Wadi which partially closing some culverts.

11. Approach
the study started by data collection of all relevant information.
The data will be manipulated using ArcGIS so as to setup the rainfall runoff model, and HEC-HMS will be used to estimate peak flows given prepared input data from GIS.
Culverts will be designed by HY-8 software.

12. Data collected Contour map of Wadi Zeimar. culverts coordinates.
rainfall stations data.
Az-Zeimar outline.
Land use
Soil type
Culverts site data

13. Study Area

14. General Wadi Az-Zeimar has a catchment area of about 140 Km2.
which starts from the eastern side at Nablus and flowing to the western side passing Tulkarm city to the Mediterranean Sea.
The Wadi Zeimar catchment area is hilly, mountainous in the eastern side, and approximately flat in the western part.

15. Figure 1: Wadi Az-Zeimar location.

16. the rainfall in the catchment is varied temporally and spatially
the rainfall in the catchment is varied temporally and spatially. It differs from a year to another.
Land use in the catchment varies from agricultural area to Industrial area and Built up area.
The area of our project is mainly composed by
Clay and clay loam soil.

17. Precipitation map for Az-Zeimar catchment

18. Precipitation (mm/year) comparison for Az-zeimar catchment rainfall staions from 2011 to 2013

20. Figure 3 : Soil type (texture)

21. Part One: Watershed Delineation

22. 1. Watershed Delineation
ArcGIS software is used to delineate the watershed.
In our project, the main use of ArcGIS was for delineation the watershed and finding stream network.

23. Watershed delineation flow chart
Az-Zeimar Contours
Culverts Locations
Watershed Delineation by ArcGIS (Hydrology toolset)
Sub-basins (areas)
Stream Network

24. Figure 6: Contours of Az-Zeimar catchment
Contours are needed primarily to get the digital elevation model (DEM) of the study area.
Figure 6: Contours of Az-Zeimar catchment
In order to delineate the watershed, Contours are needed to get the digital elevation model (DEM) of the study area
We used a 5-m interval contours

26. .
Figure 5 : Culverts locations with respect to Az-Zeimar catchment and main road

27. Figure 8: Az-Zeimar sub basins areas

29. Figure 9 : Stream network of Az-Zeimar catchment

30. Part Two: Hydrologic Modeling

31. HEC-HMS software is used for Hydrologic modeling.
The objective of this part is to make a hydrologic modeling (rainfall-runoff modeling) for Az-Zeimar watershed.
at the end we can get the design flow for the culverts.

32. Figure 8: HEC-HMS interface with Az-Zeimer model

33. Hydrologic modeling flow chart
Sub-basins areas
sub-basins SCS-CN
Hydrologic Modeling by HEC-HMS
SCS-Lag times
Muskingum parameters
Design flow for culverts
Rainfall Data

34. Loss method: SCS-CN method :
The SCS runoff curve number is an empirical parameter used in hydrology for predicting direct runoff or infiltration. 
The curve number (CN) is a function of land use and hydrologic soil group (HSG).

35. Table 1: HSG for USDA soil texture classes
Soils are divided into four hydrologic soil groups: A, B, C and D As shown in the following table.
Table 1: HSG for USDA soil texture classes
in our catchment the soil texture is distributed into clay and clay loam where they are located under group D.

36. By considering the group D for soil type, CNII (average condition) values for different land uses in Az-Zeimar Catchment were obtained as follows in table:
In our project, Curve number I (CNI) (dry condition) is considered.

37. To convert from average condition to Dry conditions
….(1)
To convert from average condition to Dry conditions
……...(2)

38. Methodology for the GIS-based SCS-CN
Land use.shp
Sub-basins.shp
Soil type.shp
ArcGIS (intersect tool)
Polygons
SCS-CN tables
CNΙΙ for each polygon
MS Excel
CNΙΙ composite for each sub basin

39. By following the last methodology, CNΙΙ and CNΙ are obtained as in the following table:

40. Initial abstraction (Ia)
is all losses before runoff begins.
It includes water retained in surface depressions, water intercepted by vegetation, evaporation, and infiltration.

42. Impervious % calculation for sub basin
1. Convert Az-Zeimar outline shapefile to KML file to open it by Google Earth.
2. Draw a polygon for each urban area inside Az-Zeimar catchment on Google earth.
3. Convert the polygons to a shapefile in order to open it by ArcGIS.
4. By Intersect tool, determine the area of urban places in each sub basin.
6. By looking to Google Earth, we assumed that the percentage of Impervious area in urban areas seems to be approximately 60%.

44. Transform Method: SCS unit hydrograph
The SCS synthetic unit hydrograph is the dimensionless unit hydrograph developed by the soil conservation service.
by using SCS unit hydrograph as Transform method for sub basins in HEC-HMS,
we were asked to provide lag time for each sub basin as an input .

45. the time of concentration in hours Where:
The basic procedure of the SCS method for getting lag time can be summarized as follows:
1.Determine time of concentration (Tc) by using the following equation:
the time of concentration in hours
Where:
L: length of flow path in feet.
V: average velocity in feet per second.
Tc: time of concentration in minute.
………(3)

46. By using ArcGIS we can find the segment-length of longest flow path and it’s slope. Then, By the following table 5 we can find the average velocity in every segment.
Table 5: Approximate average velocity (ft/s) of stream flow for calculating time of concentration

47. 2. Lag time ≈ 0.6 Tc
…….(4)
we conducted Lag Time for sub basins as in the following table:

48. Channel routing: Muskingum
Routing is a technique used to predict the changes in shape of a hydrograph as water moves through a river channel or a reservoir.
Figure 10: Inflow and outflow hydrographs from a stream reach

49. HEC-HMS program gives many options for routing in channels, one of them is the Muskingum method which we used in our project.
HEC-HMS asks for the following two parameters for Muskingum routing:
K = empirical constant usually set equal to the wave travel time through the reach. X = empirical constant that weights the relative importance of inflow versus outflow in determining the storage (varies between 0 and 0.5) ( in our project x=0.2) .

50. Travel time obtained by using the same method used for Time of concentration.
Table 7 :Travel time in minute for every reach

51. Rainfall Data of Nablus station from year1975 to 2013 is used for all sub basins.
the Design storm used in this project is SCS storm Type 2.
to find the design storm depth in mm to provide it to HEC-HMS software, an analysis of rainfall data has made as follows:

53. Figure11 : Max. annual daily rainfall Vs. Time (years)

54. Frequency Analysis
………(7)

56. Design Storm Selection Guidelines by AASHTO
Roadway Classification
Return Period
Rural Principal Arterial System
50-year
Rural Minor Arterial System
25-50-year
Rural Collector System, Major
25-year
Rural Collector System, Minor
10-year
Rural Local Road System
5-10-year
Urban Principal Arterial System
Urban Minor Arterial Street System
Urban Collector Street System
Urban Local Street System

57. The Road considered to be Rural Minor Arterial System in some places, and Urban Minor Arterial Street System in others. So, 25-year Return period will be considered in our project.
By Interpolation, the rainfall depth for 25-year return period equals 117 mm.

58. Hydrologic Modeling results

59. Part Three: Analysis and design of culverts

60. Figure 3.8: Flow chart of Culverts assessing by HY-8 software
Site-Data collection
Design flow calculation
to Hy-8
Run analysis
Over topping occur?
Yes No
Modify culvert parameters
Finish
Figure 3.8: Flow chart of Culverts assessing by HY-8 software

63. The table that used to collect site data of culverts required by HY-8 in the site

64. Common shared properties for all culverts
Concrete is used as the material of all culverts.
2. Rectangular channel type is assumed along the whole channel.
3. Street way surface is paved for all culverts.

65. Common shared properties for all culverts
4. Manning’s n coefficient of the channel is 0.04 by manning’s coefficient by chow 1959.
5. In this project, we considered Standard design embedment depth is 25 cm, less than 25 is acceptable, but more than 25 cm means the culvert’s bed need cleaning.
6. All culverts are straight.

66. Results and Recommendations

67. Culverts 2, 3, 4, 5,10, 11 and 13 are redesigned.

68. For the rest of the culverts, no overtopping has occurred
For the rest of the culverts, no overtopping has occurred. So, no redesign is needed.

69. Thanks for your attention
Any Questions?