SUSTAINABLE SITE PLANNING AND LANDSCAPING
AR. SYED ZAHID
STORMWATER MANAGEMENT Esther
Kiruba | 19171NB002
Contents Introduction Definitions Stormwater Management Factors Need for Stormwater Management Advantages & Disadvantages Environmental Benefits Sustainable Practices in Stormwater Management Conclusion
Introduction Stormwater management includes long-term regional planning. It includes site design in land areas where storm water has to be managed. Stormwater management means to manage surface runoff. It can be applied in rural
areas (e.g. to
harvest precipitation water), but is essential in urban areas where run-off cannot infiltrate because the surfaces are impermeable.
REFERENCES Stormwater Management by Beat Stauffer (seecon international gmbh Time Saver Standards (Landscape)
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EPA Stormwater is rainwater or melted snow that runs off streets, lawns and other sites. When stormwater is absorbed into soil, it is filtered and ultimately replenishes aquifers or flows into streams and rivers.
OXFORD DICTIONARY Stormwater is defined as "Water that is not absorbed into soil and rapidly flows downstream, increasing the level of waterways".
TIME SAVER STANDARDS LANDSCAPE Stormwater management is as much an art as a science, requiring judgement in the use of available data and application of calculations and techniques. At every level, stormwater management is the prediction and direction of the movement of stormwater runoff . REFERENCES Oxford Dictionary Environment Protection Agency, USA Time Saver Standards (Landscape)
STORMWATER MANAGEMENT FACTORS HYDROLOGICAL CYCLE
WATERSHED CONDITIONS
The hydrologic cycle is the entire global process of the
The amount of runoff water that flows to a particular
earth's water movement. The energy that operates the
point in the landscape is dependent upon the size of the
system comes from the sun and the earth's gravity
watershed, the portion of landscape that contributes or drains runoff to that point.
PRECIPITATION & RUNOFF Precipitation occurs as rainfall, snowfall, or mixtures of each. For site planning and design, stormwater management focuses on the estimation of runoff
LANDCOVER The character of land cover affects interception of rainfall. Generally, land cover with greater complexity will intercept more precipitation .
from rainfall.
REFERENCES Time Saver Standards (Landscape)
MOISTURE CONDITIONS Wet surfaces produce more runoff than dry surfaces . Assumptions must be made about the moisture conditions prior to a design rainfall. Typically, normal or average moisture conditions are assumed.
IMPERVIOUSNESS A major impact of urbanization on stormwater is the establishment of large areas of impervious surfaces . Imperviousness completely alters the water balance of a site by increasing runoff in terms of both volume and peak discharge.
HYDROLOGIC CYCLE
REFERENCES Time Saver Standards (Landscape)
SOILS AND INFILTRATION Infiltration into the ground is the primary cause of rainfall loss. Soil type is the principal determinant of infiltration . Sandy soils infiltrate more water at a faster rate than clay soils . Paved surfaces negate the infiltration capacity of soils . Urban soils can act very much like pavement because the porous structure of the soil has been destroyed by compaction .
SLOPE The average slope of a watershed affects the amount of runoff generated . Rain falling on flatter slopes is shed more slowly allowing more rainfall to infiltrate than on steep slopes .
DIAGRAMMATIC SECTIONS SHOWING RUNOFF AND RUNON.
REFERENCES Time Saver Standards (Landscape)
Need for Stormwater Management Maintain the natural hydrologic cycle Prevent an increased risk of flooding Prevent undesirable stream erosion Protect water quality Preventing Water Pollution Proper Site Planning
REFERENCES https://www.ontario.ca/page/understanding-stormwater-management-introduction-stormwatermanagement-planning-and-design M. L. Davis, and Cornwell, D.A. Introduction to Environmental Engineering, 1991
Advantages
Proper drainage of surface run-off
Expert planning,
Possibility to recharge groundwater
implementation, operation
and (re-)use precipitation water and
and maintenance required
surface run-off as irrigation or
Depending on the
household water
technique, a lot of operation
Treatment of stormwater in a very
and labour required
early stage
Risk of clogging infiltration
Avoids damages on infrastructure
system caused by high
(private properties, streets, etc.);
sedimentation rates
flood prevention Can be integrated into the urban landscape and provide green and recreational areas
Disadvantages REFERENCES
https://sswm.info/water-nutrient-cycle/wastewater-treatment/hardwares/semi-centralisedwastewater-treatments/stormwater-management
Environmental Benefits Measure
1. Xeriscaping (use of drought tolerant plants) and natural lawn care. 2. Safe storage, use and disposal of harmful products. Use of safer alternatives. 3. Reduced vehicle use. 4. Proper disposal of pet faeces and litter. 5. Avoid excessive use of road salt and deicers. 6. Effective parking lot and street cleaning.
Benefit
1. Water conservation and reduction of pesticides and fertilizers entering stormwater. 2. Reduction of toxic contaminants entering stormwater. 3. Improved air quality, but also reduction of oil and grease, metals and other contaminants. 4. Reduction in oxygen demanding substances, nutrients and bacteria entering stormwater. 5. Reduction of contaminants entering stormwater. 6. Reduction in sediment and many associated contaminants entering stormwater.
Sustainable Practices
REFERENCES Global Designing Cities Initiative: Green Infrastructure and Stormwater Management
SWALE
RAIN GARDENS
PERMEABLE
Swales carry water like pipes
soil filter media that can remove
PAVING
and are designed as shallow,
pollutants from road runoff.
open, planted channels to
Configure plant and soil filtration
convey runoff and remove
systems as garden
pollutants. They are an
beds or street tree pits such that
alternative to a piped drainage system where space and grade is
available. Water moves
horizontally along the surface or in subsurface
layers. Swales
they are designed to treat stormwater runoff. Rain gardens are also called bioretention systems, flat bioswales, flow-through planters, or pervious strips. Some are designed to allow water to infiltrate
sediments to improve the water
underlying soils while others are designed to collect the treated water and convey the clean water downstream.
rainfall to move through the pavement to the
slow water flow and trap
quality.
Permeable paving allows
soil beneath and provide water to landscape areas nearby. Alternate surfaces with permeable pavement to reduce stormwater runoff and recharge the water table. These may be in the form of block pavers with infiltration gaps between pavers, or porous material with infiltration
gaps within the
material. REFERENCES Global Designing Cities Initiative: Green Infrastructure and Stormwater Management
STREET TREES &
TREE PITS & SOIL
PASSIVE
PLANTING
VOLUME
IRRIGATION
Trees provide shade and cool the
Continuous tree pits increase
Directing stormwater to the
air, benefitting the comfort of
the plantable surface area and
surface of landscaped areas
people using the street. While
provide more space for tree
and tree pits provides
designing, find opportunities for
roots. Ensure sufficient growth
irrigation to the plants and
plants and trees within the
area, soil volumes, and hydration
reduces stormwater runoff
streetscape to reduce the
for trees. Coordinate tree
into local drains and
amount of hard, impermeable
planting with other
citywide systems. Passive
surface. Plan and set aside
infrastructure elements to avoid
irrigation is one of the
adequate space for trees in the
conflict, particularly with
simpler and easier ways to
early stages of development to
transportation and utilities.
incorporate water-sensitive
achieve better outcomes. Plant
Where space is constrained,
design.
trees in green strips, parking
consider employing suspended
bays, and rain gardens. High-
and permeable pavements,
quality plant stock and
strata cells, structural
appropriate planting techniques
soils, and passive irrigation to
REFERENCES Global Designing Cities Initiative: Green Infrastructure and
are vital.
improve soil conditions.
Stormwater Management
Conclusion
As architects and Environmental Designers we need stormwater management to bridge the gap between aesthetically pleasing site design and the functionality of the landscape. accentuate the movement of water as it falls and flows through the site enhance existing projects.
BIBLIOGRAPHY
1. Stormwater Management by Beat Stauffer
2. Time Saver Standards (Landscape) 3. Oxford Dictionary 4. Environment Protection Agency, USA 5. https://www.ontario.ca/page/understanding-stormwatermanagement-introduction-stormwater-management-planning-anddesign 6. M. L. Davis, and Cornwell, D.A. Introduction to Environmental Engineering, 1991 7. https://sswm.info/water-nutrient-cycle/wastewatertreatment/hardwares/semi-centralised-wastewatertreatments/stormwater-management 8. Global Designing Cities Initiative: Green Infrastructure and Stormwater Management