Roof Top Water Collection and Recharge
Availability of rain water from
roof top is so high in the urban areas and if properly
diverted and used, artificial recharge will not only
increase the groundwater availability, but also help
in reducing the water scarcity problem of cities and
towns.
Commonly run off water from roof top are let off into
the drains. Instead of this, the outlets can be connected
through a pipe to a storage tank and let into gravel
filled trenches, pits or existing open wells/tubewells
etc., to serve as recharge points.
This method is less expensive and very effective and
if implemented in good spirit by each house/housing
society, will help in augmenting the groundwater availability
of the area.
At this juncture, measures are to be
taken up by various Governmental and non-Governmental
organisations as well as the public at large, so as to
harvest the rainfall and maintain groundwater balance.
Such measures will help to have reliable and sustainable
groundwater resource for supplementing the domestic and
industrial water supply needs of urban area.
How to fit
Calculation
of Roof Flow Loads
When designing
drainage system for roofs, it is necessary to find out
the level and frequency of rainfall intensity for the
location of building concerned. Due to nature of our
climate, it is not possible to ensure complete safety
from flooding, or overview. However it is generally
satisfactory to design a rainfall intensity of 75mm/hour
where overflow will not cause damage within building
i.e. eaves gutters.
Allowance for the effect of wind is
not required when designing for horizontal surface or
other surfaces protected from wind by nearby objects.
However, an allowance should be considered where slopping
or surface occurs that are freely exposed to the wind.
One method for calculating the effective roof area, which
takes into consideration the effects of wind, is shown
below.
Calculation of effective roof area
to determine the effective roof area which allows for
contribution factor.
i.e. horizontal span of slope + half-vertical
rise between eaves and ridge x gutter length. To calculate
this in square meters:
1. Measure A, B & C in meters.
2. Use (A + (B/2)) x C = effective
roof area in meters
To calculate flow in liters/second
for 75mm/hour intensity, multiply effective roof area
(m) by 0.0208.
Direct recharge of the aquifer through
open wells will be an easier and less expensive process
in the shallow aquifer region. The rooftop run off water
can be directed into open wells through pipes and setting
pit, to avoid possible turbidity.
The tubewells used for groundwater
drawl can also be used for recharge with a valve control
between storage tank, settling pits and tubewells. In
addition to run off from roof top part of run off from
paved and other open area, can also be diverted to the
recharge pits/trenches.
The rainwater from the rooftops can
be used directly for washing purposes and for storing
the water temporarily in settling sumps for later use.
This method is less expensive but more effective. Industries,
multi storied buildings and government organisation can
implement it, as they depend mostly upon groundwater sources
for all purposes
How
it Fits
 Table
Top & Side Rafter Brackets fittings
Installation
of Gutter
Gutter
Fitting Design
Fixing
on roofs directly
Rafter Brackets |
