Urban development poses an increasing number of environmental issues, including soil erosion. It is known as one of the leading causes of land degradation.  With the jet propelling rate of urbanization and uncertainties of climate change, the impacts of soil erosion will also be on the acceleration.

1. Urban Erosion Management
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2. Introduction
 Throughout the 21st century, we are faced with a huge number of social and environmental
challenges.
 Resource managers and policymakers face daily challenges, including climate change,
deforestation, biodiversity loss, pollution, and institutional bottlenecks in global environmental
governance.
 Urban development poses an increasing number of environmental issues, including soil
erosion. It is known as one of the leading causes of land degradation.
 With the jet propelling rate of urbanization and uncertainties of climate change, the impacts of
soil erosion will also be on the acceleration.
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3. Introduction
 The erosion issue increases risks for public safety, and it is one of the leading causes to form
debris flow and collapse (Tormey, D., 2010).
 In addition, erosion limits the city's scale and slows the city's economic growth. For example, a
Chinese town named Tianshui has spent 0.5 million yuan every year on removing silt, dirt, and
sewers from its roads since 1990 (Kusuda, T., 2009).
 Due to erosion, the capacity of the city drainage system will decrease, resulting in a reduced
flood prevention capability, resulting in many cities flooding. The ability of reservoir lakes to
store and discharge floodwater will also be reduced if too many sediments accumulate.
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4. Erosion
Erosion is the process of removing soil, rock, or dissolved material from
one place on the Earth's crust and transporting it to another.
 Nearly 30 per cent per cent of the country’s total geographical area is
undergoing degradation (ISRO report).
 The main culprit is water erosion (26 per cent).
 India has committed itself to the U.N. Convention on Combating
Desertification that it would fully stop land degradation by 2030.
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Facts:
Source: researchgate.net/

5. Factors affecting the Erosion
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6. Urban vs Rural Watershed
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Source: digitalprojects
Source : megamanual.geosyntec.com

7. Why is Sediment & Erosion Control
Necessary?
 Proper erosion controls will prevent expensive, time-consuming rework of finish-grade
landscape areas after heavy rains.
 Keeping soil on the construction site will prevent polluted runoff from entering local
streams, lakes, and rivers.
 Pay Now, or Pay Later Sediment and erosion control practices, such as seeding and
mulching, stabilize the soil and prevent costly and time-consuming site rework. It makes
sense to do it right the first time to keep from having to come back to do the job over
again.
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These can all be delivered effectively
through an urban mission along the lines
of the:
 Atal Mission for Rejuvenation and
Urban Transformation (AMRUT).
 National Heritage City
Development and Augmentation
Yojana (HRIDAY).
 Smart Cities Mission.
SDG And Government schemes:
 SDGs (Goal 11): Promote urban planning as one of
the recommended methods for achieving sustainable
development.
 Habitat III, in 2016, was adopted. It outlines
principles for planning, building, developing,
managing, and improving urban areas.
 UN-Habitat (2020) mentions spatial sustainability,
as a concept. It suggests that the spatial conditions
of a city can enhance its power to generate social,
economic and environmental value and well-being.

9. Urban erosion management practices
 In urban areas, the main concern is keeping the soil covered and controlling water runoff.
 This applies to construction sites, roads, parking lots, and recreational areas. Practices that
help conserve soil in urban areas include.
 Mulching is placing a layer of straw, burlap, or other material on the top of soil to protect it
from wind and water. Mulch helps hold water and reduce the impact of water flow.
 Silt fences are placed at the bottoms of slopes to hold the soil yet allow the water to flow. This
keeps sediment out of streams and lakes and prevents the loss of soil. Silt fences may be made
out of bales of hay, plastic strips, or other materials.
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 Cover crops-Vegetation can be planted on excavated soil to hold it in place. Winter grass
can be planted in the fall on new lawn areas to prevent erosion until the following spring
when a permanent sod can be established.
 Building on the contour-Streets, buildings, and other structures can be located on the
contour of the land to slow water flow.
 Stabilizing banks-Creeks and roadsides often have banks that will quickly erode. Rip-rap,
fabrics, straw, vegetation, and concrete are some materials used to stabilize banks.
 Planting trees and shrubs-Trees and shrubs can be planted in areas where erosion is
possible. The roots hold the soil. The limbs and leaves on the tree slow the impact of rain
and fallen leaves cover the ground.
 Storm water management-Curbs, ditches, and other structures may be installed to properly
manage excess precipitation.

11. Traditional methods for erosion
management
1. Planting Vegetation
2. Contour Farming
3. Applying Mulches
4. Avoiding Overgrazing
5. Reforestation
6. Use Plastic Sheeting
7. Use of Silt Fencing
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8. Applying Terraseeding Method
9. Improving Drainage
10. Avoiding Soil Compaction
11. Matting
12. Building Terraces
13. Embracing No-till Farming
14. Laying Fiber Logs
15. Reducing Watering

12. Soil erosion control practices on the
agricultural land in Asia
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Source: sciencedirect.com

13. BMPs For Urban Erosion Control
and Management
1. Silt Fence:
 Silt fence is designed for sheet flows
 Silt fence is ineffective when it is improperly installed – it must be
trenched in (at least 6 in. deep), reinforced
 with stakes, and stakes must be positioned on the opposite side of the
fence from where runoff will Approach
 Silt fence often fails, so it must be checked regularly and maintained
clean out sediment when it backs up to 1/3 the height of the fence
 Often, one line of silt fence is ineffective; it takes multiple rows to
effectively reduce the velocity of sheet flows
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Source: cirtexcivil.co

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2. Wattles:
 Wattles are designed to reduce slope flow velocities by breaking up slope length and directing water flow.
Wattles are ineffective when installed improperly – they must be trenched and staked perpendicular to the
direction of runoff flow.
 Wattles should be tightly abutted together and the ends (at the edge of the slope) should be tilted upward
to a ‘smiley face’ that keeps water flowing toward the middle of the slope.
 On low grade slopes, wattle can be spaced farther apart, but on steep slopes, wattle should be spaced
tightly in rows or replaced with a Rolled Erosion Control Product RECP (blanket or mat).
Source: water-pollutionsolutions.com

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3. Hydroseeding:
 Hydroseeding is designed to grow new vegetation and to retain water and soil while protecting seeds.
 Hydroseeding is much more effective on an uneven and slightly compacted soil surface – slopes should be
track-walked (with tracks perpendicular to the slope) and hydro seeded more than once and from more than
one direction.
 The vegetation grown from hydro seeding will help reduce runoff volumes, runoff velocities, and raindrop
impact energy while filtering sediment, reducing pollution, and retaining soil.
Source: pinterest.com

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4. Check Dams:
 Check dams are designed to reduce channel erosion by restricting the flow velocity.
 Ideally, check dams should be made out of a material that helps to filter out sediment (loose rock [Type I or II],
fiber rolls, compost socks, bio bags, etc.)
 The toe of the upslope check dam should be equal to the height of the next check dam
 Remove sediment accumulation behind the dam as needed to prevent damage to channel vegetation and to
allow the channel to drain through the dam.
Source: megamanual.geosyntec.com

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5. Catch Basin Inlet Protection:
 Catch basin inlet protection involves using a temporary barrier to prevent and filter the flow of
sediment and debris into a storm drain or other storm water conduit. An insert bag is a woven fabric
bag installed below inlet grates that is designed to capture fine particles.
 Inlet bag material will last between three months and one year without replacement, depending on
traffic.
 Without regular maintenance (and removal of these devices when work is done), drains can become
blocked and cause flooding.
Source: shutterstock.com/search/catch-basin

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6. Sediment Cage:
 A sediment cage is designed to filter out sediment when placed over an open drain inlet.
 Cages should be placed over drain inlets on the concrete aprons surrounding the grates with the skirt
tucked under the grate.
 Water has to be able to pond around the cage and settle without over-topping the sediment cage or the
BMP will be ineffective
 Sediment piled up around the cage is a good sign that the cage is working; there should be little to no
sediment inside the trap.
Source: sedcatch.com/collections/sedcage

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7. Riprap Outlet Protection:
 Riprap outlet protection is designed to dissipate energy at the outlet of a conduit to prevent excessive
erosion (scour) from the discharge of high volume or high velocity runoff.
 Riprap is ineffective unless installed properly – fill must be compacted, and then filter stone, fabric, or a blanket
should be placed to prevent subgrade erosion before installing riprap large enough to prevent scour.
 Use extra-strength filter fabrics, installed by continuously placing the upstream section of fabric a minimum of
one foot over the downstream section of fabric.
 The outlet protection apron should be constructed with no slope along its length. There should be no over fall at
the end of the apron. The elevation of the downstream end of the apron should be equal to the elevation of the
receiving channel or adjacent ground.
Source: p2infohouse.org/ref/02/01524/urbst910.htm

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8. Soil Bank Stabilization
 To prevent erosive forces from undercutting stream banks or other steep contours, rocks or gabions
may be used to stabilize the bank. This application has the side benefit of preventing rain droplet
impact with underlying soils, which keeps sediment from leaving the site.
Source: constrofacilitator.com

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 Sponge cities are designed cities that passively absorb, clean,
and use rainfall in an ecologically friendly manner and
reduces harmful and polluted runoff.
 Permeable roads, rooftop gardens, rainwater harvesting, rain
gardens, and green spaces like ponds and lakes are examples
of related techniques.
 Sponge cities can absorb, infiltrate, retain, and purify water
when there is external precipitation, and release water when
the outside is dry. The concept of a sponge city is based on
wetlands, forests, lakes, green roofs, biological retention, and
permeable pavements. (Liang et al. 2020).
Sponge Cities concept for urban
erosion management
Typical Sponge City System
Source: springer.com/chapter

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 Improve stormwater management by adopting and developing Low Impact Development
(LID) concepts that store, recycle, and purify stormwater.
 Using more flood-resilient infrastructure (e.g., the construction of underground water-storage
tanks and tunnels) and increasing drainage protection standards using LID systems, traditional
drainage systems can be upgraded. Reducing excess stormwater and offsetting peak discharges.
 By integrating natural water bodies (such as wetlands and lakes) and enhancing ecosystem
services within drainage design, more artificial water bodies and green spaces can provide
higher amenity values.
The Sponge City concept aims to

23. Six Key Process of Sponge city
1. Retention
2. Infiltration
3. Storage
4. Purification
5. Discharge
6. Utilization
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The six hydrological processes in sponge city design
Source: researchgate.net/figure/

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Permeable asphalt concrete Permeable cement concrete Permeable Bricks
Permeable polyurethane concrete Epoxy resin microporous mixture
Commonly used permeable pavement
materials in sponge city design
Source: sciencedirect.com

25. LID’s for Urban Erosion Management
 Innovative Erosion Management Approach which Mimics Natural Hydrology
 Infiltrate
 Evapotranspiration
 Reduce/Detain Runoff
 Using a Variety of Best Management Practices (BMPs)
 Point Source Pollution Control
 Cost Effective Landscaping Techniques
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(A) Bioretention (B) Rain Garden
(C) Flow Thru Planter (D) Green Roof

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(E)Pervious Pavements (F)Permeable Pavers
(G)Green Walls (H) Creative Downspouts

28. LID Treatment Train
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Source: https://stormwater.pca.state.mn.us

29. LID’s Benefits
Environmental Benefits
 Pollution abatement
 Protection of d/s water resources
 Ground water recharge
 Water quality improvements
 Reduced treatment cost
 Reduced incidence of combined
sewer overflows
 Habitat improvement
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Land-value and Quality-of-life Benefits
 Reduced d/s flooding and property damage
 Enhanced real state value
 Increased lot yield
 Enhanced aesthetic value
 Enhanced public space/quality of life

30. Conclusion
 Using ecological engineering techniques to control soil erosion in urban areas provides
excellent potential for more sustainable soil erosion control.
 For strategic planning and project execution, it is imperative to conduct a specific site
feasibility analysis.
 Technical, financial, and environmental cost-benefit analysis must be considered by
engineers and policymakers.
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31. Future Perspectives
 The long-term impact of various climate change scenarios on bio-engineering and eco-
engineering techniques should be assessed before projects are implemented.
 Species modification and other genetic methods that change characteristics of species to adapt
to changing environmental conditions should be applied to enhance species selection and
obtain optimum results.
 A detailed interdisciplinary study of the geographic and cultural feasibility of ecological
engineering should be conducted at the provincial level.
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