In this essay we will discuss about:- 1. Introduction to Water Supply Project 2. Collection of Data for Water Supply Project 3. Factors to be Considered 4. Project Drawing Required 5. Estimates 6. Project Report.
Essay # 1. Introduction to Water Supply Project:
Water is required for any living. There are various purposes for which it is required. Without water human cannot service. Everybody has to arrange water. For supplying the water to the community through public tapes or individual house connections the first work is the preparation of the water supply project. The project is prepared after doing the field survey work and collecting the required data.
After the preparation of the project it is sent to the competent authority for sanction of grants for completing the project. When the grants are sanctioned, the Govt., departments dealing with it take up the construction of the project. While planning water supply project, care is taken to insure that it should be economical and efficient scheme to the present as well as future requirements for a considerable time.
essay # 2. Collection of Data for Water Supply Project:
During preparation of water supply project, following data are collected:
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(a) Geological data:
Geological data and survey of the ground water is done in the vicinity of the area, to know the quantity of available water at various depths in the ground.
(b) Hydrological data:
The hydrological and the available surface water sources data in the vicinity of the area are collected to determine the quantity of water available in the surface sources.
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(c) Sanitary conditions of the area:
The sanitary conditions of the area and data regarding possible sources of water pollution are collected for deciding the preventive measures against them.
(d) Topography of the area:
Survey works are done to prepare the topographical map of the area, showing elevations of the various points, density of population in different zones, this map helps in deciding the positions of intake works and treatment plants, type of system to be adopted for conveyance and distribution of water.
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(e) Legal data of lands:
Legal data of the lands to be purchased or acquired for the construction of various units of water works are collected. Legal laws on land zoning, land ownership, water rights, administrative pattern etc. are also collected, so that the acquisition of land and collection of water may not involve legal complications and delay in the construction of the project.
(f) Public opinion:
Data on the public opinions are also collected, regarding the start of the project, so that while seeking administrative approval proper justification can be given.
Essay # 3. Factors to be Considered during Preparation of Water Supply Project:
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Following factors should be considered and kept in view during preparation of the water supply project:
(i) Population:
Factors affecting the future increase in the population are to be studied and taken into account while determining the future population for the design work.
(ii) Per capita requirement:
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In India normally 200 litres per capita per day water quantity is sufficient.
(iii) Public places, parte, institutions etc.:
Water is required for the development of parks, fire-fighting and so many other purposes at public places. During preparation of water supply project a provisions of 50 litres per capita per day on average population should be taken.
(iv) Industries:
The water requirement of the existing industries as well as future industries should be thoroughly determined and, provision made in the project accordingly.
(v) Existing water supply:
For the towns where the project is being made for the expansion of the existing water supply scheme, the details of collection, conveyance, treatment and distribution of water should be thoroughly studies. The spare capacity of the existing water works should also be utilized.
(vi) Source of water:
Detailed survey of the various water available sources in the vicinity of the area should be made. Survey of the existing sources should also be made whether they are sufficient to meet the requirements of the future or not.
In case the present source of water is well, which cannot cater to the future needs, alternative water source should be considered. If the flow in the available river is less, the provision of water storage by constructing impounded reservoir should also be considered. If the river bed is sandy, collection of water through infiltration galleries may also be considered.
(vii) Conveyance of water:
Conveyance of water from source to the water treatment units, depends upon the relative levels of the two points. It may flow directly under gravity, if source is at higher elevation. If the water works are at higher elevation, it is required to be pumped.
In case the pumping is to be done, the capacity of the pumps is to be worked out. The rising mains should be designed for 30 years future population. The alignment of the rising main should be such that it should not disturb any structure in the way.
(viii) Quality of water:
The analysis of the raw water should be made to know the various impurities present in it, and for deciding the treatment of water.
(ix) Treatment works:
The various sizes and number of treatment units in the waterworks shall depend on the quality and quantity of raw water and the desired standard of water. The units of purification works are normally designed for 10 years with provision of future expansion for increasing population.
(x) Pumping units for treated water:
The pump-house is designed keeping in view the 30 years future population demand of water. Number of pumps are installed in the pump house for meeting the present water pumping requirement, with provision of 50% stand-by pumps for emergency. Additional pumps are installed as and when required.
(xi) Overhead reservoir:
The entire city or town should be divided into several zones and a reservoir should be divided for each zone. The height of the reservoir is kept such that it can supply the water to the height storey at the required pressure. As far as possible the location of the reservoir should be at the height point of the locality.
(xii) Distribution system:
The distribution system should be designed according to the master plan of the town, keeping in view the future development. The designing of the main should be done on 2-3 times the average daily flow. The design of the pipes should also taken into account the fire demand also. The mains and sub-mains should be laid along the roads and parks of the town.
(xiii) Economy and reliability:
The water supply scheme should be economical and reliable. It should draw sufficient quantity of water from the source at cheapest cost and the purification should be done upto desired limit.
Essay # 4. Project Drawings Required for the Preparation of Water Supply Project:
All the required drawings of the project are prepared which should express and give all the details of various components of the project.
In general the following drawings are prepared and used for estimating and execution of the project:
(i) Topographical map:
The topographical map of the area showing roads, location of water sources, limit of the town along with its roads, layout of pipes from source to water works etc. is prepared on a scale of R.f. = 1/500 or so.
(ii) Site plan:
The site plan of the town showing the location of the scheme and the area to be served is also prepared on a scale of R.f. = 1/500 or so.
(iii) Contour map:
The contour map or plan of the entire area is prepared on a scale of 1: 100, showing the location of water mains, sub-mains, branches, valves, fire- hydrants, pumping, stations, service reservoirs, roads, streets etc. is prepared. The site plan and service reservoirs, roads, streets etc. is prepared. The site plan and the contour plan may also be combined together. In this case the contour lines are drawn on the site plan itself.
(iv) Flow diagrams:
The flow diagram of the entire scheme is prepared showing the sequence of operations and all aspects of the scheme. The approximate sizes of purification and distribution mains are also given on these diagrams.
(v) Detailed drawings:
The detailed drawings of the various units and components of the scheme are prepared. All the dimensions including hydraulic and structural details are given on these drawings. The 1 section of the mains and branches are plotted. The details of the treatment units etc. are also prepared.
Essay # 5. Estimates for Water Supply Project:
The cost of the water supply project depends on the types of sewer, length of rising mains, type of treatment required, pumping machinery size and design of reservoir, distribution system etc.
The cost of various parts of the water-supply schemes may be taken approximately as follows for guidance:
The above percentages are for guidance which can be used for preparation of preliminary estimate for administrative approval. The detailed drawings along with detailed estimate are prepared for the execution of the project and obtaining technical sanction of the project from the head of the concerned engineering department.
The technical approval or sanction of the project estimate gives a kind of guarantee that the public money will be safely and soundly used on the project. After obtaining all the approvals and allotment of funds, the tenders are called and the work is awarded for execution to a suitable agency.
Essay # 6. Project Report for Water Supply Project:
After doing the survey work, preparing drawings and estimates of the water supply scheme, the project report it written.
The project report deals with the following points:
(i) Introduction of the project.
(ii) Necessity of the improved, additional or new water supply scheme.
(iii) The area of the city or town with population, industries, cattle to be served.
(iv) The basis of calculation and allowance of water per capita.
(v) Future provisions in the project.
(vi) The quality and quantity of raw water available in the selected sources for the project.
(vii) The possible additional water sources which can be used in future for the expansion of the scheme.
(viii) Nature of the proposed water supply, i.e., intermittent or continuous etc.
(ix) The method of designing the pipe sizes and the formulae used.
(x) Design of all units of water works, intakes overhead service reservoirs.
(xi) Design of distribution system.
(xii) The annual cost of running the pumps.
(xiii) Recurring expenditure for running the scheme.
(xiv) Cost of treated water ready for distribution and supply rate in per million litres.
(xv) Design period of the scheme etc.