2. INTRODUCTION
rain and snow melt that runs off surfaces such
as rooftops, paved streets, highways, and
parking lots.
As water runs off these surfaces, it can pick up
pollution such as: oil, fertilizers, pesticides, soil,
trash, and animal waste.
From here, the water might flow directly into a
local stream, bay, or lake. Or, it may go into a
storm drain and continue through storm pipes
until it is released untreated into a local
waterway.
3. In addition, the large impervious surfaces
in urban areas increase the quantity of
peak flows of runoff, which in turn cause
hydrologic impacts such as scoured
streambeds channels, instream
sedimentation and loss of habitat.
5. Human Health:
Stormwater can contain toxic metals, organic
compounds, bacteria, and viruses.
Untreated stormwater is not safe for people to
drink and is not recommended for swimming.
Polluted stormwater can lead to beach
closures for swimming and shellfish harvesting.
It can also trigger toxic algal blooms.
9. Drinking Water:
Untreated storm water discharging to the ground
could contaminate aquifers that are used for drinking
water.
10. Degraded Water Quality:
Virtually all of our urban creeks, streams, and rivers are
harmed by storm water pollution.
Storm water is the leading contributor to water quality
pollution of urban waterways.
11. Impaired Habitat: In Washington, urban stormwater
harms and pollutes streams that provide habitat for
fish and wildlife. Alterations to the watershed, such
as building homes and other structures and clearing
away trees and shrubs, are the leading causes for
stormwater pollution. Federal agencies identified
habitat loss from stormwater runoff as one of the
primary obstacles to salmon recovery.
13. STORM DRAIN
13
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.
14. designed to drain excess rain and ground water
from paved streets, parking lots, sidewalks, and
roofs. Storm drains vary in design from small
residential dry wells to large municipal systems. They
are fed by street gutters on most motorways,
freeways and other busy roads, as well as towns in
areas which experience heavy rainfall, flooding and
coastal towns which experience regular storms.
Many storm drainage systems are designed to drain
the storm water, untreated, into rivers or streams.
STORM DRAIN
16. Storm water drainage includes:
Roof drains
Gutters
Building storm drains
Road drains
Catch basins
Storm water pipes
17.
18.
19. What happened if rain water not properly collected
and disposed?
Nuisance and health hazard
20. How to discharge the
storm water?
In the past, many cities situated near large lakes,
rivers, or the ocean, used a combined sewer system
to convey both storm water and sewage.
This is no longer permitted by code.
Exceptions can be made in hardship cases with
prior approval from local authority.
With this approval, new construction can discharge
into a dual storm water and sewage system.
Otherwise, the code now requires separate sewage
and storm water collection systems.
21. Professional engineers usually size the storm water
drainage pipes and determine the method of
disposal.
26. URBAN STORM WATER
MANAGEMENT
Nowadays, flash flood occurs in the cities
and towns.
This is caused by the sprawl urban
development in these particular areas.
As these urban areas have emerged, it
creates more impervious areas such as in
Kuala Lumpur, Pulau Pinang and Johor
Bharu in Malaysia.
29. In addition, the amount of impermeable
areas will increase for many purposes of
land use. The transitions from forest and
open spaces areas to the commercial
and industrial areas have caused
significant changes directly to the local
ecosystem.
30. In other words, the natural processes i.e.
the physical, biological, chemical
processes have been disturbed due to
the unplanned development. In
hydrological perspectives, the important
physical processes in hydrological cycle
have been disrupted by this kind of
development.
31. The surface runoff may change its flow
path significantly due to the land
characteristics are always changed.
The increased of impervious areas do not
allow infiltration process to the ground.
Development also cut trees and
vegetation where the transpiration
process will be eliminated. It will cut the
natural vegetation.
32. This will result the rise of surface runoff volume
and create flooding problem. The drainage
system is very important infrastructures to
cater the flow of runoff from catchment
areas. However, drainage failure will lead to
surcharged and flooding problem as well.
Most of drainage facilities and silt trap did not
maintain very well. It may create significant
problem such as blockage, pipe leakage etc.
It also increases the volume of sediment in the
system.
33. THE IMPORTANCE OF URBAN
STORM WATER MANAGEMENT
Storm water management has a little
interest compared to wastewater and
water resources management due to less
pollution in a longer period.
*Traditionally, most of the countries had
applied the conventional drainage
system where all the surface runoff must
be discharged directly to the nearest river
or stream.
34. The practice of urban drainage has been
traced back to some of the earliest
recorded histories of mankind.
This practice of conveyance of
stormwater from urban areas to safer
places will involve engineering solutions
for the reduction of flood damage
potential and water pollution.
35. The open drain and culvert are
commonly used over the years in
Malaysia to cater the flow directly to the
river. However, as the urbanization raise
rapidly, the channels capacity insufficient
to cater to high volume of runoff before
the flows entering to the receiving
watercourse.
36. The policies of stormwater management
have been introduced to limit the runoff
characteristics after development to
those that existed prior development. It is
required to merge the storage and
treatment facilities in the drainage system
network to control the runoff from new
development area before the water is
allowed to enter the nearest river or
stream.
37. CAUSES OF STORM WATER
POLLUTION
Changes in land use that increase impervious cover
lead to flooding, erosion, habitat degradation, and
water quality impairment.
Everyday activities such as driving, maintaining
vehicles and lawns, disposing of waste, and even
walking pets often cover impervious surfaces with a
coating of various harmful materials.
Construction sites, power plants, failed septic systems,
illegal discharges also contribute substantial amounts
of contaminants to runoff.
Improper sewer connections lead to unseen storm
water pollution.
Sometime sewer overflows, septic tank leakage also
causes pollution.
38. EFFECTS OF STORM WATER
POLLUTION
This pollution, in turn, impacts important natural
resources as well as other, equally important activities
such as commercial and recreational fishing,
swimming, and boating.
Flooding and Property Damage
Siltation and Sedimentation
Harm to Aquatic Life
Human Illness
Impacts to Drinking Water Supply
Aesthetic Losses
39. STORM WATER TREATMENT
Basic Principal is to prevent pollutants from entering the
water in the first place
In case of Storm Water, we need to ensure that surfaces
through which stormwater run-off passes over should as
far as possible be free from solids and other wastes.
Structural Method
Treatment systems
Erosion and sediment controls
Vegetated volume reduction devices
Typical structural methods are include grassy swales,
infiltration trenches and basins, sand filters, Bio-retention
cells, wet and dry retention ponds, constructed wetlands,
and porous pavement.
40. Non Structural Method
Impervious cover minimization
Land-use planning
Conservation of natural areas
Some Best Management Practices, such as
green infrastructure, Low Impact Development
however, are more effective than others,
because those BMPs that are infiltration-based
also help maintain or restore the natural
hydrology of the watershed.
41. GREEN INFRASTRUCTURE
Green infrastructure (GI) can be defined as the
natural and man-made landscapes and features
that can be used to manage runoff.
Examples of natural green infrastructure include
forests, meadows and floodplains.
Examples of man-made green infrastructure include
green roofs, rain gardens and rainwater cisterns.
Rain gardens
it is a planted depression or a hole that allows rainwater
runoff from impervious urban areas.
It reduce the rain runoff by percolating or consuming
rain water
Green infrastructure replicates the natural functions
of a landscape by integrating functions like storage,
detention, infiltration, evaporation, and transpiration,
or uptake by plants.
42. LID employs principles such as preserving and
recreating natural landscape features
Minimizing effective imperviousness to create
functional and appealing site drainage that treat
stormwater as a resource rather than a waste
product
Example of LID are Bio-retention facilities, rain
gardens, vegetated rooftops, rain barrels, and
permeable pavements.
Objectives of LID are Preserve and recreate
natural landscape features, Reduce effective
impervious cover, facilitate detention and
infiltration opportunities.
LOW IMPACT DEVELOPMENT
43. Traffic volume
Roadway design
Surrounding land use
Regional climate
Accidental spills
Frequency of Rainfall
For Example-
roadways carrying an average of 30,000 vehicles
per day may produce runoff with two to five times
the pollutant levels found in runoff from rural, less-
traveled highways or roadways in arid areas.
FACTORS AFFECTING STORM
WATER TREATMENT
44. BENEFITS OF STORM WATER
MANAGMENT
Minimizing or avoiding the creation of
polluted storm water.
Reducing environmental impacts on the
lakes, rivers and watersheds
Achieving greater harmony with the water
cycle in the watershed
Potentially reducing municipal water supply
requirement by using storm water as an
alternative water sources.
Minimizing health risks.
