1. Population forecasting Lecture 1

2. Design Period 2 Technical Lifetime : Technical Lifetime : It represents the period during which it operates satisfactorily in a technical sense. The suggested periods for the main distribution system components shown in the following table : ComponentPeriod ( Years ) Transmission main30 - 50 Distribution main30 - 100 Reservoirs20 - 80 Pumping station - facilities20 - 80 Pumping station - equipment15 - 30 Technical Concerns Economical Concerns

3. Estimation of design period 3

4. Estimation of population 4 النمو السكاني الطبيعي نتيجة للتناسل يتراوح عادة مابين 1% إلى 7% حسب المجتمعات وعاداتها وتقاليدها، وعلى سبيل المثال في المجتمع الفلسطيني تتراوح معدل النمو الطبيعي من 3% إلى 6% ، ففي مدينة كمدينة غزة يبلغ معدل النمو الطبيعي 4.5% ، بينما تبلغ الزيادة في معسكر جباليا حوالي 6%. بينما تبلغ النسبة كمتوسط في جميع أنحاء فلسطين 2.5% ، ويوضح الجدول التالي توقع مركز الإحصاء الفلسطيني للسكان :

5. Population forecasting 5 Arithmetic increase method الطريقة الرياضية This method assume that the population density increase uniformly Population after time t Present population population growth rate by each t unit This equation can be simplified to:

6. Uniform percentages Method طريقة ذات النسبة المنتظمة (Geometric Increase ) Predicted curves Method طريقة المنحنيات التوقعية (curvilinear method) population growth rate by each t unit 6

7. Example 7 Estimate the population number after 30 year, if the initial population number is 100,000. the population growth rate is 3% Method 1 Method 2 Method 3

8. Population Saturation and urban planning 8  Master Plane Land-Use General laws Although the population forecasting methods gives the population at the end of the design period, the maximum possible population is also estimated according to the number of apartment and stories per unit area and the maximum family members. The Saturation population can be determined using the Master plan for the area and its general laws. The minimum of the two values is taken in consideration when the network is designed.

9. Example 9 A residential area 100,000 m² and population of 4200 capita has the following Master Plan : 25 % of the total area is for Streets. 5 % of the total area is for green Areas. 70 % of the total area is for buildings. 60 % of the building area is for building. If the family living there consists of members and the average apartment area is 150 m², Calculate the Population needed for designing a water distribution system to serve that area for 25 years if you are given that the growth rate of the population = 3 %.

10. Cont. example 10 0.7 × 100,000 = 70,000 Total Building Area (m²) 0.6 × 70,000 = 42,000Building Area (m²) 42,000 × 5 = 210,0005 Stories Building Area 210,000 / 150 =1400No. of Apartments 1,400 × 5 = 7000 capitaSaturation Population

11. Area Study Residential Area Public Area Commercial Area Agricultural Area Streets

12. %Area (m 2 )Item 100641 DuonmTotal Area 81519,917Residential Area 319,230Public Area 425,640Commercial Area 212,820Agricultural Area 638,460Industrial Area 425,640Streets

13. Population Density Calculation of total number of residents: 1. Normal Increase ( using equations) Example: - Total Area of Southern Remal = 2,754 Dounm - Total population in Southern Remal in 2002 = 17,500 - Total population in Southern Remal in 2008 = 29,300 Statistical Data Hypothetical figures

14. Continue.. Population in Area under consideration:

15. Population Density 2. Saturation population Total Residential Area = 519,917 m 2 Total number of population under saturation condition = 45,721 + 59,918 = 105,639 Towers (6 floors and more) Regular Buildings (5 floors or less) 149,795370,122Area 83Avg. no. of floors 140170Avg. area of flats (m 2 ) (149,795/140) x 8(370,122/170) x 3# of flats 77Avg. no. of persons/flat 59,91845,721No. of residents

16. Population Density Therefore, Population density= Population / Total Area = 99,435 / 641,000 = 0.155 person/m 2