Drainage- Sub- drains, Culverts, Ditches, Gutters, Drop inlets and Catch Basins,Rain Water Disposal for individual buildings, Rain Water Harvesting with examples and illustration for 4th sem.archi. ,P.T.U
Building Services :Drainage, Rain Water Disposal and Harvesting
• SUBMITTED TO –
AR. VIKRAMJEET SINGH
COLLEGE OF ARCHITECTURE
· Drainage- Sub-
Ditches, Gutters, Drop
inlets and Catch
· Rain Water
· Rain Water
STORM DRAINAGE SYSTEMS
A storm drain is defined as that portion of the storm drainage system that receives
runoff from inlets and conveys the runoff to some point where it is then discharged
into a channel, water body, or piped system.
It consists of one or more pipes connecting one or more inlets. A storm drain may
be a closed-conduit, open-conduit, or some combination of the two.
The terminology "storm sewer" which has been in general use for many years, is
gradually being replaced with the term "storm drain" to differentiate between
sanitary sewers and storm drains. Storm drain will be used throughout this manual.
THE PURPOSE OF A STORM DRAIN IS TO COLLECT STORM WATER RUNOFF FROM THE ROADWAY
AND CONVEY IT TO AN OUTFALL. STORM DRAIN DESIGN GENERALLY CONSISTS OF THREE
system planning which includes that
gathering and outfall location;
pavement drainage which includes
pavement geometries and inlet spacing;
location and sizing of the mains and
REQUIREMENT FOR THE STORM WATER DRAINAGE
Stormdrain systems should have adequate capacity so that they can accommodate runoff that enters the system for the design frequency.z
Storm drain systems should be designed with future development in mind if it is appropriate.
The storm drain system for a major vertical sag point that can't overflow elsewhere until the depth of water is two feet or greater, should have a greater level of
flood protection to decrease the depth of ponding on the roadway and bridges.
Where feasible, storm drains shall be designed to avoid existing utilities.
The recommended minimum distance is 10 feet when the storm drain system is parallel to the waterline and 1foot when the storm drain system crosses a
Attention shall be given to the storm drain outfall design to insure that the potential for erosion is minimized.
Drainage system design should be coordinated with the proposed staging of large construction projects in order to maintain an outlet throughout the construction
The placement and hydraulic capacities of storm drainage structures and conveyances should be designed to take into
considerationpotential damage to adjacent property and to minimizetraffic interruptionby flooding as is consistent withthe
importance of the road, the design traffic service requirements, and available funds.
Storm drain placement and capacity should be consistent with local storm water management plans.
A subdrain system is an underground network of piping used to remove water from areas that collect or retain surface water or
The network can be rather small, such as might be used to drain a limited area, or fairly large to drain a sizeable number of acres.
Surface water can be collected into the subdrain system by installing a surface inlet or catch basin.
Groundwater is collected by allowing water into the pipe through perforations.
Both surface water and groundwater can be discharged to an appropriate outlet such as a nearby storm sewer, pond, or river.
Both storm drains and subdrains are installed underground to carry water away from homes and businesses.
Storm drain pipes are connected to the aboveground storm drain grates and primarily carry surface water runoff through the system.
Subdrain pipes are not directly connected to the storm drain grates.
instead, subdrain piping contains holes that allow the intake and passage of groundwater through the underground system. Subdrain
piping has been installed in some areas of the City where high groundwater tables exist.
A culvert is a drainage pipe used to convey a stream through a road or embankment or
may carry a stream for a long distance underground to a surface discharge location.
- Three Sided
Concrete Box Culvert
Its installation does not
require a large quantity of pipe.
Pipe Arch (CAPA)
High Density Polyethylene
Reinforced Concrete Pipe
Culverts are generally short in length and
open at both ends and often must
withstand substantial traffic loads
Ditches are constructed to convey water from storm runoff to an
A good ditch is shaped and lined using the appropriate vegetative or
structural material and does not cause flooding, erosion, or
Energy dissipating structures to reduce velocity, dissipate turbulence, or
to flatten flow grades in ditches are often necessary.
Importance to Maintenance & Water Quality
Efficient disposal of runoff from the road will help preserve the road bed and banks.
Well vegetated ditches slow, control, and filter runoff providing an opportunity for
sediments to be removed from the runoff water before it enters surface waters.
In addition, a stable ditch will not become an erosion problem itself.
This will help alleviate roadway flooding, reduce erosion, and thus reduce
• THAT PORTION OF THE ROADWAY SECTION ADJACENT TO THE CURB WHICH IS UTILIZED TO
CONVEY STORMWATER RUNOFF.
• A COMPOSITE GUTTER SECTION CONSISTS OF THE SECTION IMMEDIATELY ADJACENT TO THE CURB
Rain gutter, a narrow trough or duct which collects
rainwater from the roof of a building and diverts it
away from the structure, typically into a drain.
Street gutter, a depression which runs alongside a city
street, usually at the curb and diverts rain and street-
cleaning water away from the street and into a storm
The gutter also helps to reduce erosion, prevents leaks in
basements and crawlspaces, protects painted or stained
surfaces by reducing exposure to water, and provides a means
to collect rainwater for later use.
A curb and gutter forms a triangular Channel
that can be an effective hydraulic conveyance
facility which can convey runoff of a lesser
magnitude than the design flow without
interruption of the traffic.
Where curbs are used, composite gutter sections
can be effective at increasing gutter capacity
And reducing spread on the pavement
A location where storm water runoff from an open area enters the storm
Drop inlets are usually part of the public drainage system, but can
sometimes be considered private.
Types and uses of drop inlets
In driveways &parking
where water is intersepted
over a large area
A catch basin is a structure in the form of a chamber which is provided along with the sewer line to admit clear rain
Water free from silt, grit, debris, etc, into the combined sewer.
Catch basins allow rainwater runoff to be safely collected to prevent road and property flooding.
Catch basins are designed specifically for capturing and conveying stormwater.
These are small masonry chamber (75 to 90 cm in DIA. And 75 to 90cm deep)which are constructed below the street
inlet to prevent the flow of grit, sand, etc, in the sever lines.
When stormwater enters these basins the grit, sand etc, settle down in the bed and the storm water free from all the
enters the sewer.
The outlet pipe of the catch basin is fixed 60 cm above the bottom (see pics).
The outlet pipe is provided with a trap to prevent the escape of odours from the sewers to the catch basins.
Catch Basin Types & Uses
Catch Basin Uses
Catch Basin Type 1
With Catch Basin Type 1
Curbed grass medians
On Curb and Gutter where it
protrude into the travel lane
Catch Basin Type 1 (Special)
Curbed Grass Medians
Catch Basin Type 9
In Ditches Outside of the
In Low Areas Outside of the
In ditches, valleys or low
pedestrian traffic is
Not to be used in the path
Catch basin type 14
Median ditches on dual lane
Side ditches on controlled
Low areas on controlled access
where there should be no
In paved medians with
barrier May be a single
basin or double basin
On curb and
On valley gutter
catch basin at
On curb and gutter
On valley gutter
the face of
catch basin at the
back of paved
In low point on curb and
In low point on valley
gutter sections with
face of catch basin at the
back of paved lip
Catch Basin Type 17
Catch Basin Type 18
Catch pits should be provided in the following sections-
• When the sewers are laid at very small gradient, and the velocity of flow is less than self cleansing
velocity. At such situations as the solids present in the sewage will not move and go on accumulating and
will require continuous cleaning and maintenance of the sewer, which can be reduced by providing catch
• When the drains are passing along the water bound macadam road or in sandy area and the
market(where lot of defuse is dropped in drains).Because in such areas if all the solids moving in the
sewage are allowed to enter the sewage, they will choke the sewer line.
The catch basin collects the solids from the storm water.
These solids are to be removed at frequent intervals for the proper
functioning of the catch basins, otherwise they will block the passage
of storm water to the sewers, resulting in the flooding of streets .
Rain water disposal for individual buildings
Heavy rainfall and long periods of rainfall can lead to problems with
To reduce the likelihood of flooding the Building Regulations require all
rainwater from new developments to be discharged by means other than
This can include soakaways, storage tanks or into watercourses.
The most common form of rainwater disposal is directly into the ground
through soakaways, but storage tanks are becoming more popular as a
form of rainwater harvesting.
Rain Water Harvesting
Rainwater harvesting is the accumulation and deposition of rainwater for reuse before it reaches the aquifer.
Rainwater harvesting is the process of intercepting storm-water runoff and putting it to beneficial use.
Rainwater Harvesting is the collection of water that would otherwise have gone down the drain, into the ground or been lost through
Ground water resource gets naturally recharged through percolation. But due to indiscriminate development and rapid
urbainzation, exposed surface for soil has been reduced drastically with resultant reduction in percolation of rainwater, thereby
depleting ground water resource.
Rainwater harvesting is the process of augmenting the natural filtration of rainwater in to the underground formation by some
artificial methods. "Conscious collection and storage of rainwater to cater to demands of water, for drinking, domestic purpose &
irrigation is termed as Rainwater Harvesting."
Why harvest rainwater ?
• To arrest ground water decline and augment ground water table
• To beneficiate water quality in aquifers
• To conserve surface water runoff during monsoon
• To reduce soil erosion
• To inculcate a culture of water conservation
This is perhaps one of the most frequently asked question, as to why one should harvest rainwater.
There are many reasons but following are some of the important ones.
Advantages of rain water harvesting
Rainwater harvesting provides
an independent water supply
during regional water
restrictions and in developed
countries is often used to
supplement the main supply.
It provides water when there is
a drought, can help mitigate
flooding of low-lying areas,
and reduces demand on wells
which may enable ground
water levels to be sustained.
It also helps in the availability
of potable water as rainwater
is substantially free of salinity
and other salts.
By harvesting and using rainwater we can:
Increase water availability for on-site vegetation
Reduce on-site flooding and erosion
Reduce water bills and groundwater pumping
Extend the life of landscaping (rainwater is usually
low in salt content and relatively high in nitrogen)
There are generally two methods of harvesting rainwater-
1.Passive Rainwater Collection
Passive rainwater collection is the act of slowing down rainwater and letting it infiltrate on site
rather than channeling it into the storm drain system.
A passive system uses earthworks to control surface water flow and uses the soil as the storage
container. Intercepted rainwater can be collected, slowed down and retained or routed through
the site landscape using microbasins, swales and other water harvesting structures.
Redirecting the roof downspout into a landscaped area is an example of pasive rainwater
Active rainwater collection systems integrate a storage container, a tank or cistern, into the
system to catch rainwater runoff for later use on the property.
These tanks can be installed above or below ground. Above ground systems usually rely on
gravity to disperse the water and serve smaller areas.
The in ground system requires a pump but can provide water throughout the site.
In either case active systems bring a great advantage -- water can be stored and used
when the soils are dry (instead of while the ground is soaked from the same rain that filled
Active systems are also more complex than passive systems, cost more and require more
The concentration of contaminants is reduced significantly by diverting
the initial flow of run-off water to waste.
Improved water quality can also be obtained by using a floating draw-off
mechanism (rather than from the base of the tank) and by using a series of
tanks, with draw from the last in series.
The stored rainwater may need to be analyzed properly before use in a way
appropriate to ensure its safe use
The quality of collected rainwater is generally better than that of surface
water. Contamination is always possible by airborne dust and mists, bird feces,
and other debris, so some treatment may be necessary, depending on how the
water will be used.
Quality of harvested water
Rainwater harvesting systems can be installed with
The system should be sized to meet the water demand
throughout the dry season since it must be big enough to
support daily water consumption.
Specifically, the rainfall capturing area such as a building
roof must be large enough to maintain adequate flow.
The water storage tank size should be large enough to
contain the captured water
Rainwater harvesting can be harvested from the
Rooftops: If buildings with impervious roofs are already in place, the catchment area
is effectively available free of charge and they provide a supply at the point of
Paved and unpaved areas i.e., landscapes, open fields, parks, stormwater drains,
roads and pavements and other open areas can be effectively used to harvest the
runoff. The main advantage in using ground as collecting surface is that water can be
collected from a larger area. This is particularly advantageous in areas of low rainfall.
Waterbodies: The potential of lakes, tanks and ponds to store rainwater is immense.
The harvested rainwater can not only be used to meet water requirements of the city, it
also recharges groundwater aquifers.
Stormwater drains: Most of the residential colonies have proper network of
stormwater drains. If maintained neatly, these offer a simple and cost effective means
for harvesting rainwater.
From where to harvest rain
A rainwater harvesting system comprises components of various stages -
transporting rainwater through pipes or drains, filtration, and storage in tanks for
reuse or recharge. The common components of a rainwater harvesting system
involved in these stages are illustrated here.
COMPONENTS OF A RAINWATER HARVESTING SYSTEM
1. Catchments: The catchment of a water harvesting system is the surface which
directly receives the rainfall and provides water to the system. It can be a paved area
like a terrace or courtyard of a building, or an unpaved area like a lawn or open
ground. A roof made of reinforced cement concrete (RCC), galvanised iron or
corrugated sheets can also be used for water harvesting.
2. Coarse mesh at the roof to prevent the passage of debris.
3. Gutters: Channels all around the edge of a sloping roof to collect
and transport rainwater to the storage tank.
4. Conduits- Conduits are pipelines or drains that carry rainwater
from the catchment or rooftop area to the harvesting system.
Conduits can be of any material like polyvinyl chloride (PVC) or
galvanized iron (GI), materials that are commonly available
A first flush device is a valve that ensures that
runoff from the first spell of rain is flushed out and
does not enter the system. This needs to be done
since the first spell of rain carries a relatively
larger amount of pollutants from the air and
(i) Charcoal water filter
A simple charcoal filter can be made in a drum or an earthen pot. The
filter is made of gravel, sand and charcoal, all of which are easily
(ii) Sand filters
Sand filters have commonly available sand as filter media. Sand
filters are easy and inexpensive to construct. These filters can be
employed for treatment of water to effectively remove turbidity
(suspended particles like silt and clay), colour and microorganisms.
In a simple sand filter that can be constructed domestically, the top
layer comprises coarse sand followed by a 5-10 mm layer of gravel
followed by another 5-25 cm layer of gravel and boulders.
The filter is used to remove suspended pollutants from rainwater
collected over roof. A filter unit is a chamber filled with filtering
media such as fibre, coarse sand and gravel layers to remove
debris and dirt from water before it enters the storage tank or
recharges structure. Charcoal can be added for additional
Broadly rainwater can be harvested for two purposes:
Storing rainwater for ready use in containers above or below
Charged into the soil for withdrawal later (groundwater