Design model of residential water demand in al-Najaf city

الملخص EN

This paper investigates the analysis of residential water demand for Al- Najaf city which is (Population of about 541918 person, living in an area of 5.82 Km2 according to Central Committee of Statistics–Najaf Census Directorate-1997) along with determining the factors that affect such demand for the period from the 1st of October-2005 to the end of August–2006.

The cross-section data which was weekly observed was collected by a survey made on a sample of randomly chosen dwellings from different districts of the city.

A questionnaire survey was also made to collect all necessary information seemed useful in estimating the daily consumption of domestic water.

Demand relations are estimated for total residential, winter, summer, and Sprinkling demands.

Stepwise multiple regression analysis was employed to find the structural relationship between water demand per household per day and household characteristics (factors) for each type of demand.

All demand models were fitted in log-linear form.

In this survey, the average daily water demand for the city of Najaf was estimated to be 1221 l / h / d (177 l / c / d) for total demand, 745 l / h / d (108 l / c / d) for winter demand, 2754 l / h / d (399 l / c / d) for summer demand, and 556 l / h / d (81 l/c/d) for sprinkling demand.

The most significant factors effecting on the demand are appeared in the fitted equations.

Household size was found to be the most significant variable in winter and sprinkling demand models, while the number of families was found to be the most significant variable in the total, and summer demand model.

The pressure was found to be the significant variable in winter and summer demand models, while the number of showers was found to be significant variable in the total and summer demand model.