Geoscience Reference
In-Depth Information
national highways including Prime ministers Golden Quadrilateral Project
Connecting whole of India north-south and west-east.
2. Methodology
The location and design of sustainable rainfall harvesting system requires
hydrogeological study of the area as well as subsurface information of most
permeable zone.
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Besides, average rainfall and rainfall intensity need to be
analyzed as per climatic zones. Based on normal rainfall and above normal
rain fall intensity, the rain water harvesting system should be designed
in such a way that 70%-80% run off is send back to groundwater regime
after natural filtration process. As present paper has a limited scope of
harvesting rainwater falling on the major roads, the designs are restricted
to this purpose only.
3. Concept
In designing rainwater-harvesting system, capturing rainfall run off from
the roads, and creating artificial connectivity to subsurface water in the
hygienic manner is the key-concept. The effectiveness of the concept lies in
reasonable cost, coverage of large areas, and immediate implementation and
immense benefits in terms of additional water availability, improvement in
water quality, increased plantation, maintaining eco-balance, etc.
4. Design
The sustainable design of rainwater harvesting along roadsides fall under
two categories:
(a) The area with soil/weathered rock having vertical permeability up to
water level zone. In this kind of situation, the percolation pit method
would be suitable. In this method, the pits of average dimension, 3 m
depth, 3 m long, 2 m wide can be made along the roads between side
lanes and main road. These pits may be made at every 500-meter
interval along both the sides of the road as shown in Fig. 1. The pits
should have natural filtration media of coarse sand, gravels and pebbles
and should be covered with perforated slabs. The road should have
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slopes towards these pits from the divider.
(b) The area having impermeable zones prior to water level, like clays,
solid rocks etc. In this type of areas, the rainwater-harvesting system
