A water supply project generally consists of a water collection unit, conveyance system, and units for treatment, purification, and distribution. It is necessary to plan, prepare, and design the entire water supply scheme before constructing the units. A proper plan will ensure that an efficient and economical system is finalized with minimum expenses. The scheme should be such that it can be constructed within the allotted budget while permitting future expansion.
1. Data Collection
Before planning for the water supply project, the following data have to be collected:
1.1 Hydrological Data
Hydrological data gives an overview of the long-term monitoring of the water sources that exist in the vicinity. The data will help in estimating the total availability of surface water.
1.2 Geological Data
The geological data will help in understanding the rock composition and other aspects of the ground surface. This will help in estimating the availability of land.
1.3 Water Requirement of the City
It is necessary to know the population count and its water needs. In case there is an industry in the vicinity, information regarding its water requirements also need to be found out. The current water demand and future requirements can be forecasted with this data.
1.4 Existing Water Supply Projects
The data on existing water supply projects in the vicinity will help determine the additional net availability of water. Moreover, the extra requirement of water can be calculated.
1.5 Sanitary Conditions of the Area
Along with the data on the sanitary conditions of the area, other sources of pollution must also be known. In case there is contamination of water due to multiple sources such as industries, factories, etc., then the cause should be identified, and remedial measures should be taken for the same.
1.6 Topography of the Area
This information is very important as it will highlight the low-lying areas and ridges concerning the available source, population density, etc. The intakes, treatment works, and distribution reservoirs can then be planned accordingly by considering an economic conveyance system.
1.7 Legal Data
The legal data is essential to stay out of any legal issues involving water rights, land ownership, land zoning, clearances, etc. The land options should be evaluated and the location with minimum legal approvals would pose as an ideal location for setting up the treatment plant.
1.8 Public Opinion
The public opinion will not only help in counteracting the claims of the government in an event of dispute regarding land acquisition, but also be helpful while seeking expenditure sanctions and approvals from the authorities.
2. Project Formulation
Once all the necessary data has been collected, it should be analyzed and the future needs must be evaluated. The following activities should be carried out in the project formulation stage:
- Estimation of the population trend for the present and future based on the local conditions to identify the quantity of water required to be fulfilled by the project.
- Locating a reliable source(s) of water so that all the demands of the community are met.
- If needed, make provisions for the storage of water and design the system required to transmit the water from its source to the consumers.
- Determination of the characteristics (physical, chemical, and biological) of the available water.
- If needed, design the water treatment facility to improve water quality up to the standard of potable water.
- Design the layout and units of the distribution system. It must include pumping stations, storage facility, size of pipes, fire hydrants, valves, and other important details.
- Make provisions for the establishment of an organization to look after, maintain, and operate the units after construction.
3. Project Drawings
Drawings are a crucial part of the project as the entire plan and design of the components of the project are expressed by it. The following drawings are generally prepared and used for execution purposes:
3.1 Topographical Map
The topographical map shows the features of the area and includes sources of supply, roads, etc. In certain maps, the layout of the pipes that convey water from the source to the city may also be included. The scale of the map may be 1:500 or so.
3.2 Site Plan
A site plan of the town showing the location of the scheme and the area to be served by the scheme should be prepared. A scale of 1:500 may be used.
3.3 Contour Plan
A contour plan is essential as it shows the location of the water main, sub-mains, valves, branches, hydrants, pumping stations, etc. Sometimes, the contour plan and the site plan are combined to form one plan.
3.4 Flow Diagrams
The flow diagram includes the line plan and section and also shows the sequence of operations.
3.5 Detailed Drawing
Detailed drawings include components and units along with their dimensions and both structural and hydraulic details. The drawing should include different sections of the mains and branches, treatment units, etc.
4. Project Estimates
A preliminary estimate can be prepared once the preliminary drawings are made. It will give a tentative idea about the cost, and the same can be communicated to the authorities for seeking approval and sanctioning expenditure. In addition to the cost of the components and units of the system, the rough estimate must also include the cost of pump houses, staff quarters, etc. The tentative costs of the water supply system are given in Table-1.
| Sl. No. | Component item | Cost of the item (%) |
| 1 | Pumping stations | 18 |
| 2 | Distribution system | 50 |
| 3 | Treatment plant | 10 |
| 4 | Supply penstock | 9 |
| 5 | Reservoirs | 6 |
| 6 | Buildings for housing operational staff, etc. | 2 |
| 7 | Meter and other contingencies | 5 |
| Total | 100% |
After the formalities regarding the project approvals are completed, the detailed drawing and estimates are to be prepared. On obtaining the administrative approval, the competent authority of the concerned engineering department will sanction the estimate. After that, the bidding procedure for the execution of work can be carried out.
5. Project Reports
The project estimates and the drawings should always be supported by a report. It should justify the necessity of the project, the economic feasibility along with the benefits, and must have the pros and cons of any alternative proposals, the actual designs, proposed water rates, etc.
FAQs
The basic components of a water supply system include a water collection unit, conveyance system, and units for treatment, purification, and distribution.
A proper plan ensures that an efficient and economic scheme is finalized along with minimum expenses. Thus, it is pivotal to devise a good plan for constructing a water supply scheme.
The project report justifies the project estimates and the drawings. It also states the necessity of the project, the economic feasibility along with the benefits, and must have the pros and cons of any alternative proposals, the actual designs, water rates proposed, etc.
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