Engineering Hydrology Notes for Prefinal - PDF

WATER SUPPLY A. Water Demand – the quantity of water that is needed by the population to be covered. The water to be supplied should be sufficient to cover both existing and future consumers. In addition to the projected consumptions, an allowance for non-revenue water (NRW) that may...

WATER SUPPLY A. Water Demand – the quantity of water that is needed by the population to be covered. The water to be supplied should be sufficient to cover both existing and future consumers. In addition to the projected consumptions, an allowance for non-revenue water (NRW) that may be caused by leakages and other losses should be included.  Water demand are influenced by the following factors: o Service of water to be implemented o Size of the community o Standard of living of the populace o Quantity and quality of water available in the area o Water tariffs that need to be shouldered by the consumers o Climatological conditions o Habits and manners of water usage by the people B. Service Level 1. Level I (Point Source) – This level provides a protected well or a developed spring with an outlet, but without a distribution system. The users go to the source to fetch the water. This is generally adaptable for rural areas where affordability is low and the houses in the intended service area are not crowded. A Level I facility normally serves an average of 15 households within a radius of 250 meters. 2. Level II (Communal Faucet System or Stand Post) – This type of system is composed of a source, a reservoir, a piped distribution network, and communal faucets. Usually, one faucet serves four to six households within a radius of 25 meters. It is generally suited for rural and urban fringe areas where houses are clustered in sufficient density to justify a simple piped system. The consumers still go to the supply point (communal faucet) to fetch the water. 3. Level III (Waterworks System or Individual House Connection) – This system includes a source, a reservoir, a piped distribution network, and individual household taps. It is generally suited for densely populated urban areas where the population can afford individual connections. C. Water Demand Computation 1. Demand Variations and Demand Factors  Minimum day demand – the minimum amount of water required in a single day over a year.  Average day demand – the average of the daily water requirement spread in a year.  Maximum day demand – the maximum amount of water required in a single day over a year.  Peak hour demand – the highest hourly demand in a day. Demand Parameter Demand Factor Minimum day demand 0.3 of average day demand Average day demand (ADD) 1.0 Maximum day demand 1.3 of average day demand Peak hour demand 2.5 of ADD (>1,000 connections) 3.0 of ADD (