Sustainable Storm-water Management Report

SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN

BACHELOR OF QUANTITY SURVEYING (HONOURS)

BUILDING SERVICES 1 [BLD 60403]SUSTAINABLE STORMWATER MANAGEMENT

LOH MUN TONG 0323680

LEW QUO MING 0322884

LEONG LI JING 0323628

DARREN TAN QUAN WEN 0322662

TAM ZHAO WEI 0322587

YEE JYH LIN 0322408

LECTURER: MS. LIM TZE SHWAN

SUBMISSION DATE: 23 NOVEMBER 2016

TABLE OF CONTENT

NO. TOPIC PAGE

1. INTRODUCTION OF SUSTAINABLE STORMWATER MANAGEMENT 2

2. SUSTAINABLE STORMWATER MANAGEMENT SYSTEM,

INSTALLATION PROCESS, ADVANTAGES AND DISADVANTAGES

2.1 Green Roofs

2.2 Pervious Surfaces

2.3 Grassed Swales

2.4 Bioretention Areas

2.5 Rain Gardens

2.6 Detention Ponds

2.7 Retention Ponds

2.8 Wetlands

2.9 Rills and Channels

2.10 Underground Storage

2.11 Hydrodynamic Separators

3 - 31

3. SUSTAINABLE STORMWATER MANAGEMENT ADVANTAGES &

DISADVANTAGES

32 - 33

4. CASE STUDY 34 - 64

5. POSSIBLE PROBLEM TO THE SYSTEM 65 - 66

6. RECOMMENDATIONS FOR FUTURE IMPROVEMENT 67 - 71

7. LEARNING FROM THE GROUP PROJECT 72

8. REFERENCES 73 - 75

9. BIBLIOGRAPHY 76 - 77

10. APPENDICES 78 - 80

INTRODUCTION OF

1

SUSTAINABLE STORM-WATER MANAGEMENT

Storm water are usually water from snow/ice or from nearby stream, river or runoff surface.

Such as rooftops, paved streets, highways, and Parking lots. However, in natural sentiment

such as forest, the soil absorbs much of the storm-water. The plant helps to hold the storm-

water also using it as food for reproduction and etc. In developed place such as cities,

unmanaged storm-water can create 2 types of problem. First problem would be flooding and

water pollution.

Water pollution, is due to the impervious surface such as parking lots; road and building that

the storm-water are unable to be absorbed by the ground. Therefore, generating more runoff

than natural sentiment. This runoff will then collect all kinds of pollutant from roads, lawns,

roof and etc. It is then washed away to the nearby river, lake and ocean. Which then causes

the runoff to be untreated therefore causing pollution to the river, lake and ocean

Next is flooding, because of all the objects that are collected during rain. It will all be

transported to a drain causing it to block it. Which in the end creates a flash flood, causing all

kinds of problem to the cities. Such as traffic jam and so on.

To combat storm-water, a storm drain is installed throughout the cities. It is designed to drain

excessive rain from impervious surfaces such as paved streets, car parks, parking lots and

etc. it consists of one or two pipes connecting to an inlet. Storm drain may consist of closed-

conduit, open-conduit or a combination of two. Over the years the terminology of storm

sewer has been replaced into storm drain, to differentiate between sewerage and storm

drains.

SUSTAINABLE STORM-WATER MANAGEMENT SYSTEM

2

Naturally, rainwater is absorbed and soaked into the ground and then it evaporates from the

surface, taken up by plants, or finding its way slowly into rivers or streams. Any development

will affect and make an impact to this environment and change the natural water cycle.

Hence, storm-water system is designed based on the project, site conditions, water

availability and regional climate. The system can be structural devices or non-structural

devices, incorporates both natural environment and engineered systems.

Green Infrastructure & Gray InfrastructureGreen infrastructure functioned as water management that protects, restores, or mimics the

natural water cycle. It is effective, economical and enhances community safety and quality

life. Gray infrastructure is man-made designed to move urban storm-water away from the

built environment. Both infrastructure is involved in storm-water management system.

2.1 GREEN ROOFS

3

Green roofs are a multi-layered system with living plants growing on roof top. It built up with

a series of layers where each performing a specific function. The most typical built up

includes roof deck, waterproofing layer, protection layers, drainage layer, filter sheet,

growing substrate and vegetation. Green roofs enable rainfall infiltration and

evapotranspiration of stored water. The vegetation and soil absorb and filter the water. The

vegetation design to remove air particulates, produce oxygen and provide shade. The heat

energy produced during evapotranspiration enable the water evaporates from the plants.

Hilton Bankside, London Silver City Townhomes in Milwaukee

4

Installation Process:1. Get a structural engineer to check on the roof whether it needs more joists,

strengthen existing ones, or add bracing.

2. Prepare the roof with some pitch so that it sheds water toward gutters, preferably 1/4

inch per foot of run for green roof.

3. A second layer of rubber roofing membrane is to be installed as a root barrier in order

to prevent damage to the roof.

4. Planted trays of vegetation that has been nurtured at a nursery are moved by forklift

or crane to the rooftop.

5. Before the trays are installed, decorative L-shaped aluminium edging is temporarily

weighted down around the edge of the roof where it will cover the sides of the trays.

6. The planted trays are to be set at the lowest end of the roof, moving across and up

the roof’s slope.

7. Connect the planted trays together with a modular system so that they can be

removed from the roof for maintenance without disturbing the others.

8. Feet is to be built under the trays to keep them elevated 1/2 inch above the roof’s

surface so that runoff can easily flow underneath toward the gutters.

9. A gas-powered concrete saw fitted with a masonry blade is used to cut the trays in

order to fit in perfectly the entire green roof.

10. After a couple of rows of trays are in place, the soil elevators are to be pulled out at

an angle in order to avoid removing the growing medium. This helps the roof to blend

together almost instantly and reduces air space between the trays, increasing the

system’s insulating R-value.

5

11. It is best to have least walking on the plant. Then, from a ladder, the edging to the

sides of the modules with exterior-grade screws are to be secured.

12. Once the trays are installed, they are watered to settle the soil.

ADVANTAGES DISADVANTAGES

Provide a barrier of greenery that helps to

protect the waterproof membrane

underneath and thus increase the lifespan

of the roof

An increase in weight load (require more

structural support to be implemented)

Provide wildlife habitats and create green

space

A greater expense compared to traditional

roofs

Help filter pollutants from air and improve

air quality

Require extra maintenance (require

watering, feeding and weeding)

Boosting thermal performance Not appropriate for steep roofs

Maintenance- Removal of trash and debris regularly

- Inspection and replacement of plants will be required on a regular basis

6

2.2 PERVIOUS SURFACESPervious surfaces can be either porous or permeable. Porous surfacing is a surface that

infiltrates water across the entire surface while permeable surfaces designed to allow storm-

water runoff to filter through surface voids into an underlying stone reservoir for temporary

storage or infiltration. It consists of a surface pavement layer, an underlying stone aggregate

reservoir layer, optional underdrains and geotextile over uncompacted soil subgrade. The

most commonly used surfaces are pervious concrete, porous asphalt and permeable

interlocking concrete pavers (PICP).

EPA’s Edison Environmental Centre in Edison, NJ

7

Installation Process:1. Preparation of the subgrade that is to be trimmed to level and compacted to a

tolerance within +20mm to -30mm in accordance with the ‘Specification for Highway

Works’.

2. For System C pavements (no infiltration into the subgrade) it is recommended that

the surged is trimmed with a nominal fall to allow water collected in the bottom of the

pavement to drain towards the outlet points.

3. For System A pavements (full infiltration into the subgrade) a geotextile shall be

installed between the sub-base and subgrade.

4. A capping layer is required in all System C pavement.

5. The capping layer shall be installed according to ‘Specification for Highway Works’

and the capping materials shall meet the requirements as well.

6. The surface texture of the capping is to be smooth and dense so that the impervious

membrane will not be damaged.

7. For light duty applications, a Category 1 impervious membrane of minimum 2000-

gauge polythene with double taped overlapping joints shall be used. For heavier

applications, a Category 2 impervious membrane shall be used.

8. The sub-base may be comprised of the Coarse Graded Aggregate (CGA) only or

CGA overlaid with Hydraulically Bound Coarse Graded Aggregate (HBCGA).

9. The pervious CGA sub-base shall be laid in 100-150mm layers and compacted to

ensure that the maximum density is achieved for the particular material type and

grading without crushing the individual particles or reducing the void ratio below the

design value.

10. Pervious concrete block paving shall be manufactured and tested following the 2003

Concrete Paving Blocks requirements and tests methods.

8

11. The block layer is to be installed in accordance with BS 7533 - 3: 2005 A1: 2009,

‘code of practice for laying precast concrete paving blocks and clay pavers for flexible

pavements and shall follow the process set out in the flow chart, Annex A, figure A1’.

12. Prior to hand over, the pavement shall be inspected to ensure compliance to the

specification. Any non-compliance shall be corrected before handing over.


Have a long useable life Risk of long-term clogging and weed

growth if poorly maintained

Reduced need for deep excavations for

drainage, which can have significant cost

benefits

Cannot be used where large sediment

loads may be washed/carried onto the

surface

Simple to design and construct

Reduced effects of pollution in runoff on

the environment

Maintenance- Periodic vacuuming

- Repair and patch surfaces with similar pervious materials

9

2.3 GRASSED SWALESGrassed swales are shallow, broad and vegetated channels designed to allow storm-water

to slow down and go through the process of sedimentation, filtration, evapotranspiration and

partially infiltration. It normally located along the roadway. The collected storm-water is

expected to drain away through the soil within several hours or days. Check dams and

berms can be installed across the flow path to promote settling and infiltration. Wet swales

treat storm-water through physical and biological action while dry swales through infiltration

according to their design.

Wet Swales at Sue Donaldson Dry Swales at Delaware Department of

Transportation a. Wet Swales

10

Installation Process:1. To construct a properly functioning grassed swale, accurate grading is essential.

2. Machinery used for excavation and grading should not be driven over the swale site

in order to avoid compaction of soil.

3. Protection towards the swale site should be strengthen so that the storm water runoff

that will cause erosion and sedimentation during construction won’t affect the swale

site. Until the adjoining areas draining into the swale are stabilized, final grading and

planting should not occur.

4. During the final stages of grading, any accumulation of sediments that does occur

must be removed.

5. The bottom of dry swale should be tilled to produce a highly porous surface.

6. During establishment of vegetation, installation of erosion control matting or

blanketing to stabilize soil is highly recommended.

b. Dry Swales

Installation Process:1. Protection during the site construction should be carried out properly in order to assure a

smooth construction of dry swale.

2. Installation may only begin after the entire contributing drainage area has been stabilized

by vegetation.

3. Additional E&S controls may be needed during the construction of dry swale, particularly

to diver storm-water from the dry swale until the filter bed and side slopes are stabilized.

4. Pre-treatment cells should be excavated first to trap sediments before they reach the

planned filter beds.

5. Excavators or backhoes should work from the sides to excavate the dry swale area to

the appropriate design depth and dimensions.

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6. The bottom of the dry swale should be ripped, root-tilled or otherwise scarified to

promote greater infiltration.

7. An acceptable filter fabric should be placed on the underground (excavated) sides of the

dry swale with a minimum 6-inch overlap.

8. Add the soil media in 12-inch lifts until the desired top elevation of the dry swale is

achieved and wait for a few days to check for settlement. Add additional media if needed.

9. Install check dams, driveway culverts and internal pre-treatment features, as specified in

the plan.

10. Prepare planting holes for specified trees and shrubs, install erosion control fabric where

needed, spread seed or lay sod, and install any temporary irrigation.

11. Plant landscaping materials as shown in the landscaping plan, and water them weekly

during the first 2 months.

12. Conduct a final construction inspection and develop a punch list for facility acceptance.


Good removal of urban pollutants Individual swales can only treat a small area

Reduces runoff and promotes infiltration,

which in turn, controls peak discharges

Wet swales can be a breeding ground for

mosquitoes and other diseases

Low capital cost Require extra maintenance

Easy to incorporate into landscaping Limit the opportunities to use trees for

landscaping

Pollution and blockages are visible and easy

to remove


- Grass cutting and removal of cuttings

- Clearing of inlets, culverts and outlets to avoid clogging

- Repair of eroded areas by fill in seed with grass and soil

- Replace damaged vegetation

2.4 BIORETENTION AREAS

12

Bio-retention areas are similar with rain gardens which are also the combination of soil and

plant materials. Bioretention areas are designed with a higher standard. It specially designed

and engineered to manage and treat storm-water runoff. It is a shallow landscape

depression which included soil mixes and control structures such as under drains to aid the

control of flow, catch basins to filter sediment, check dams to slow the water flow.

Bioretention areas are commonly found on commercial properties or any public areas.

Baltusrol Crescent, Melbourne

Installation Process: 1. Protect bioretention areas during construction by not establishing the installation until

site is built out and pervious areas are stabilised.

2. Make sure the original design still works by studying the soil borings.

3. Verify the actual contributing drainage area boundaries and confirm inlet and outlet

elevations.

4. Excavate from the side and in order prevent compaction of the precious bottom by

keeping heavy equipment on the outside.

5. For larger bioretention areas, use a cell construction approach by breaking it into 500

to 1000 square feet temporary cells with earth bridges between.

6. Protect the bottom and make sure the bottom is level.

13

7. Rip soils to maintain porosity.

8. Install filter fabric on sides only.

9. Lay down stone layer with clean washed stone. The depth depends on the design.

10. Install under drain if necessary and make sure that the correct ends are capped.

11. Add filter media and make sure pre-mix meets standards, add in one foots lifts, allow

for 10% settlement, rake out to final ponding depth a few days later.

12. Lay down surface cover with mulch, turf or stone and inspect thickness of layer. The

ponding depth has to be within 9-12” range.

13. Establish final elevations and dig planting holes with at least 3-foot-deep holes for

trees (away from underdrains).

14. Install landscaping materials.

15. Stabilise perimeter side slopes and buffer and make sure that all these vulnerable

areas are protected by silt fences, geotextiles, and/or hydroseeding.

16. Construction inspection is to be carried out in order to make sure that all the works

are completely done and prepared.

17. First growing season maintenance is to be carried out such as regular watering first

few months, spot re-seeding, remove or replace dead plants and etc.

18. Final construction inspection has to be done after 6-12 months of installation.


Very effective in removing urban

pollutants

Not suitable for areas with steep slopes

Reduces amount of runoff from drainage

areas

Relatively expensive to construct

Enhancing the beauty of yards and

communities

Susceptible to clogging if surrounding

landscape is not managed

Provide wildlife habitats Require extra maintenance

Maintenance- Regular inspection

- Removal of trash and debris regularly

- Replacement of mulch layer

- Vegetation management

2.5 RAIN GARDENS

14

Rain gardens contains plants that can survive in soil soaked with water and it can also

collect and slow the storm-water runoff and increase the infiltration into the soil. Rain

gardens practice mimics natural hydrology by the process of infiltrating, evaporating and

transpiring the storm-water runoff. Rain gardens can be installed in almost any unpaved

space and are commonly found on private properties. Rain gardens collect the water and

settle it on the garden surface then soak through the plants and filter media. Any sediments

are trapped on the surface of the garden. The soil and plant roots work together to filter the

water naturally.

Greenest Street in America, Chicago

Installation Process:

15

1. Meet with all concerned parties to ensure that the team understand the entire

construction project and to review plans to ensure the percolation test was done for

every rain garden on the project.

2. Erosion-control and sediment-control strategies, such as tarps, silt fences, compost

socks, or compost berms are to be developed.

3. Find out what other onsite storm-water management practices are planned, such as

pervious pavements or pavers.

4. Keep other contractors’ equipment off the future site of the rain garden by using

temporary fencing and signs and avoid impacting other parts of the site by keeping

the equipment off existing soils and root zones of mature vegetation.

5. Identify and mark clearly of staging areas for materials and equipment, and locations

for storing or reusing excess soils.

6. Before excavation, review calculations to know how deep to dig and the proper

elections to place the inflow and overflow.

7. Excavation according to the plan and mixing rain garden soils are best to be done

during the dry months in order to prevent soil compaction.

8. Establish any required pipes and/or swale for inflow and overflow.

9. Set the inflow and overflow locations.

10. Install plants at the right timing of the year can reduce irrigation needs later.

11. If planting is planned considerably later than excavation and soil work, cover the soils

with mulch or plastic sheeting to prevent erosion and retain the integrity of the rain

garden soil mix.

12. Apply clean rock or other materials to the inflow and overflow.

13. Remove all erosion-control and sediment-control devices only when construction is

complete.

14. Verify that an inspection plan and operations & maintenance plan are in place.


16

Can be designed to work in most

soil types

Not suitable for areas with steep slopes

Only requires a minimum amount of

space

Cannot tolerate large volumes of water due

to its smaller size

Provide wildlife habitats Require extra maintenance

Enhancing the beauty of yards and

communities

Susceptible to clogging if surrounding

landscape is not managed

Collects and improves water quality

Maintenance- Vegetation management


- Inlet and outlet cleaning

- Cover garden with shredded mulch to reduce weeds and retain moisture

2.6 DETENTION BASINS

17

Detention basins are open and flat areas of grass that are normally dry during low flow

periods. Detention basins designed to allow filtration and sedimentation process to take

place. It also designed to provide temporary storage and flow control for storm-water runoff

attenuation for both quality and quantity management. Detention basins works by allowing a

large basin area for water and the water slowly drains out through the outlet at the bottom as

designed.

Ponds in a detention basin


18

1. Install all temporary erosion and sedimentation controls

● The area immediately adjacent to the basin must be stabilized in accordance

with the PADEP’s Erosion and Sediment Pollution Control Program Manual

(2000 or latest edition) prior to basin construction

2. Prepare site for excavation and/ or embankment construction

● All existing vegetation should remain if feasible and should only be removed if

necessary for construction.

● Care should be taken in order to avoid compaction of the basin bottom.

● Clear the area to be excavated of all vegetation if excavation is required.

Remove all tree roots, rocks, and boulders only in excavation area.

3. Excavate bottom of basin to desired height (if necessary)

4. Install surrounding embankments and inlet and outlet control structures

5. Grade subsoil in bottom of basin, taking care to prevent compaction. Compact

surrounding embankment areas and around inlet and outlet structures.

6. Apply and grade planting soil

7. Apply geo-textiles and other erosion-control measures

8. Seed, plant and mulch according to Planting Plan

9. Install any anti-grazing measures, if necessary


Surrounding areas have vegetative buffer

that can withstand dry or wet conditions.

Requires a large amount of space

Simple to design and construct Does not improve water quality

Relatively long lived facilities Breeding grounds for mosquitoes and

other diseases

Can be designed to work in most

soil types

Limited pollutant removal capabilities




- Sediment monitoring and removal

2.7 RETENTION PONDS

19

Retention ponds are open areas of shallow water which designed to accommodate water

and provide temporary storage for excess water. It designed to improve the quality of water

through settling, often employed as flood control devices. The water level rises temporarily

and retain a permanent pool of water. Retention ponds allows large amounts of water to

enter the pond and allows small amounts of water drains out through the outlet because the

pond need to maintain the permanent water level.

Seven Oaks

Installation Process:1. Separate wet pond area from contributing drainage area:

● All channels/pipes conveying flows to the wet pond should be routed away

from the wet pond area until it is completed and stabilised.

● The area immediately adjacent to the wet pond should be stabilised in

accordance with the PADEP’s Erosion and Sediment Pollution Control

Program Manual (2000 or latest edition) prior to construction of the wet pond.

2. Clearing and grubbing:

20

● Clear the area to be excavated of all vegetation

● All tree roots, rocks and boulders are to be removed

● All stump holes, crevices and similar areas with impervious materials to be

filled

3. Excavate bottom of wet pond to desired height (rough grading)

4. Install surrounding embankments and inlet and outlet control structures

5. Grade and prepare subsoil

6. Apply and grade planting soil

● Matching design grades is crucial because aquatic plants can be very

sensitive to depth

7. Apply erosion-control measures

8. Seed, plant and mulch according to Planting Plan

9. Install any anti-grazing measures, if necessary

10. Follow required maintenance and monitoring guidelines


Provide wildlife habitats Requires a large amount of space

Simple to design and construct Can be a drowning hazard

Naturally processes water without

additional equipment

Negative water quality impacts if not

properly designed

Collects and improves water quality




- Sediment monitoring and removal

2.8 WETLANDS

21

Wetlands generally consists of shallow ponds and marshy areas, covered almost entirely in

aquatic vegetation. Wetlands allow the wastewater to be treated by the process of

sedimentation, filtration, digestion, oxidation, reduction, adsorption and precipitation. Natural

wetlands filter the contaminated water running into the stream, river or ocean. Constructed

wetlands filter the water flow from inlet pipe and gravel through wetland plants under some

process and finally flow out from outlet pipe and gravel for further treatment.

Natural Wetlands at Ramsey-Washington Metro Watershed District.

Constructed Wetlands from Gold Coast City Council

a. Natural Wetlands

22

b. Constructed Wetlands

Installation Process:1. Basin construction including common earth moving, excavating, levelling, compacting

and construction of berms/walls.

2. The cut and fill on the site should be balanced in order to avoid the need for remote

borrow pits or soil disposal.

3. If there’s existence of agronomic-quality topsoil on the site, it should be stripped and

stockpiled.

4. Berms should be constructed in conformance with standard geotechnical

considerations.

5. Lining of the basin is needed if the permeability of the soil is greater than 10-6 m/s.

6. In order to prevent liner punctures during placement and subsequent construction

activity, proper care should be taken.

7. A layer of sand should be placed beneath the liner and levelled if the surged contains

sharp stones.

23

8. Filling the basin with substrates in conjunction with inlet/outlet arrangements.

9. The substrate should be washed to eliminate soil and other fines that could block the

void spaces, which may lead to substrate clogging.

10. Construction of inlet and outlet structures.

11. The distribution of holes in the network of inlet arrangement for wetlands should be

placed in order to assure equal distribution of wastewater throughout the entire area

of the wetland.

12. Same goes to the arrangement of the network of outlet so that there’s no short-

circuiting takes place inside the wetland.

13. Planting vegetation such as transplanting roots, rhizomes, tubers, seedlings, or

mature plants; by broadcasting seeds obtained commercially or from other sites.


Can tolerate both great and small

volumes of water

Requires a large amount of space

Relatively inexpensive to construct Breeding grounds for mosquitoes and

other diseases

Provide wildlife habitats Unable to treat highly toxic modern

wastewater

Good removal capability or urban

pollutants



- Vegetation management to retain high vegetation coverage

- Sediment monitoring and removal when required

2.9 RILLS AND CHANNELS

24

The system is designed to be an open surface water channels that allow to collect water,

slow down and provide storage for slit and oil. The outlets are designed as a mini oil

separator, so it is very effective at treating pollution. The system allows water flows along

with the variety of cross sections rills and channels that suit the urban landscape.

Rill Installation Process:1. Use concrete as a base for a butyl liner will keep the liner fold-free.

2. For flowing water, a gradient has to be created over the length of the rill.

3. For strong lines, leave a rill unplanted, or use it to make a channel of water planting.

4. Make a sketch before starting the construction to help estimate quantities and types

of materials.

5. Dig a channel where you want to put the rill. Make this large enough for the finished

size you want.

6. A finished width of between 30-60cm and a finished depth of 24-45cm are useful

dimensions. Topsoil can be taken away or reused elsewhere.

7. Check that the top of the rill is level on either side.

8. Rake the base of the channel, then pour a 10-15cm layer of concrete to cover the

base.

9. Cover with a plastic sheet if rain is forecast and leave to set. Line the sides of the

channel using concrete blocks, laid in stretcher bond using mortar.

10. Build the sides up to the height you need. The top of the blocks will be just above the

level of the water when the rill is completed.

11. When the mortar has set, line the channel with a pond liner underlay. Then fit the

liner into the channel, smoothing out the creases and folds. Secure it along the edges

temporarily with large stones.

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12. Mix a waterproof additive into the mortar. Fill the rill with water.

13. Trim the liner but leave about 15-20cm to lie underneath the edging stones of the rill.

14. Install edging of the rill using appropriate foundation and bedding method.

15. Set bricks, slabs or stones so that they overhang the top between 2.5-5cm,

depending on the size of the paving unit.

Channel Installation Process:1. Dig trench for the channel drain, allowing for 50mm deep compacted sand base and

wide enough for a minimum of 100mm backfill of concrete on each side.

2. Fix a string line to finishing height of grate 2mm below final surface level.

3. Allow a fall approx. 5mm for every 1m length (1:200).

4. Start installation at lowest point of the run to accommodate any cut lengths which

should be installed at the point furthest from the outlet.

5. Join two lengths of channel by interlocking them at each end.

6. Use an end cap at highest point of the channel drain.

7. Connect the lowest end of the channel drain to 110mm PVC drainage pipe using

either an end outlet or the preformed channel bottom outlet to allow water to drain

away.

8. Install with grate.

9. Protect grate with tape before concrete is poured.

10. Pour concrete and finish 2mm above level of grate. Allow 72 hours to cure before

vehicle use or removing grates.

11. Insert a screwdriver into the slots provided, twist and lift to remove the grate.

12. If installing block paving or paving slabs, haunch around channel with concrete to a

height which allows the depth of the block or slab to finish 2mm above the level of

grate.


Very effective in water & pollution Need to give careful consideration to

26

treatment crossings

Simple to design and construct Incorrect planting can cause silt build up

Can be visually appealing in urban

landscapes

Flood risk reduction

Maintenance


- Routine maintenance

- Intensive maintenance required one every five years

2.10 UNDERGROUND STORAGE

27

Underground storage tank system is a storage tank with underground piping connected to

carry storm-water from detention or retention ponds. The system consists of storage

structures, inlet and outlet pipes that fitted and attached together underground. The addition

features at the inlet pipes helps to improve the water quality by removing floatables, oils and

grease, and sediments. Underground storage tank system cooperates with other storm-

water system to achieve the best result.

Installation Process:1. Pre-installation testing of the storage tank.

2. Excavation and foundation backfill to be carried out so that the bottom is free of any

large rocks or objects that would interfere with laying a smooth, level bed of backfill.

3. A storage tank installer must establish whether a concrete slab and/or a geotextile

filter are necessary to secure the excavation.

4. If there will be traffic above the installation, or if the excavation base is soft or

uneven, a reinforced concrete slab or other stabilizing material may be required

below the backfill bedding.

5. The kind of anchoring system has to be determined during the installation process.

6. Installation of the storage tank has to be carried out properly.

7. Prior to bringing the backfill to the top of the storage tank, some storage tanks require

additional testing.

8. The inspectors must verify that the storage tank is vented and that all piping

connections to and from the tank are corrosion-resistant and flexible.


28

Protected damage from animals and

natural disasters

Relatively expensive due to their

specialised construction

Space saving since it is installed

underground

Require extra maintenance

Maintenance- Inspection and prevention of leakage and spills

- Clean up by soil and groundwater investigation and remediation

- Corrosion protection for tanks and piping

- Cleaning and disposal of trapped sediments


29

2.11 HYDRODYNAMIC SEPARATORSHydrodynamic separators consist of internal components which are permanent pool for

sedimentation with inlet and outlet pipes which able to create flow patterns and flow

conditions that aids in sediments removal. It is an underground storage structure and smaller

size compared to underground storage tank system.


1. Ensure correct lifting equipment is used and is connected to the designated anchor

points on the units.

2. During handling and installation, avoid impact with any site objects that may cause

damage to the units.

3. Position the base followed by the intermediate unit on the foundation. Use a

recommended bitumen based sealant such as Tokstrip between all units, ensuring

the ends overlap to provide a permanent water-tight seal.

4. Before the main component unit is lowered onto the intermediate unit, check that no

site debris has entered the internal chamber.

5. The main component unit is to be lowered to ensure that the inlet and outlet points

are correctly aligned for accurate connection.

6. Complete the build with the top unit to cover level. Slab access orientation to be

positioned directly over the central tube for the purpose of inspection and routine

maintenance.

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7. Backfill around the unit with a suitable material up to a level below the inlet and outlet

points.

8. To complete the process, pipe connection to the inlet and outlet points and final

backfilling is to be covered.

9. Prior to operation, fill the unit with water until it flows from the discharge pipe. The

sump is now full and the hydrodynamic separator is ready for use.


Relatively effective for removal of

pollutants

Only can remove limited amounts of

pollutants

Space saving since it is installed

underground

Requires frequent maintenance to remove

captured material

Maintenance- Cleaning and disposal of sediments and oils


- Inspection and prevention of leakage or spills

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STORMWATER MANAGEMENT ADVANTAGES & DISADVANTAGESAdvantages

Road SafetyA storm drain's primary purpose is to give the rainwater a place to go as opposed to

collecting in the streets and, potentially, flooding your home. By removing the run-off water,

the storm drains take it off the road, making it safer to travel on. Storm drains also help

reduce the amount of ice on the roads by giving run-off water a place to go during mid-winter

thaws.

Home ProtectionRainwater that does not have a storm drain to flow into will continue to build up until it finds a

place to go. An advantage of storm drains is that they give the water a place to flow out of

your driveway and your yard so it doesn't build up and flow into your home.

ChemicalsThe water that runs into a storm drain does not go to a water treatment plant. Storm drain

water is directed to the nearest water source to reduce the water level in the streets and

around homes. This sounds ideal until you realize that lawn chemicals used to kill weeds

and bugs run off your lawn, onto the street, down the storm drain and back into your local

water supply. The same thing happens when people dump chemicals into the storm drain

because it looks like a disposal area.

TechnologyWhile storm drains offer a way for rainwater to escape from city streets and front yards, they

are still just metal grates in the street. Debris from the run-off water can easily clog storm

drains and render them useless. Unless there is someone out there constantly cleaning off

the storm drain grate during a storm, the grate may reach the point where it is not help but

rather a cause of water build-up.

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Disadvantages Maintenance

One of the most inconvenient things about drainage systems is the maintenance. This is a

must because if the drainage system gets clogged, then it will not work properly. Check for

blockages and debris that may be blocking the flow of water.

TreesThe problems with trees are that their roots will not work very well with drainage systems.

The main issue is related to the roots of the trees. To ensure proper drainage, you will need

to make sure that there are not trees near the trench of the drain. You may need to divert the

flow of water or move a few trees, if possible.

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CASE STUDY

Location: Duluth, Minnesota, United States

Address: 1049 University Dr, Duluth, MN 55812

Total area: 10,520,000 Sq. Ft.

Impervious Area: 3,100,000 Sq. Ft.

Treated Impervious Area: 1,000,000 Sq. Ft.

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The University of Minnesota Duluth (UMD) is a regional branch University of Minnesota

system. This campus has 244 acres overlooking Lake Superior and consists of 50 buildings

including the Tweed Museum of Art, the Marshall W. Alworth Planetarium, Weber Music Hall

and the Marshall Performing Arts Centre. It also consists various facilities such as the

research and field studies centre, Glensheen Historic Estate, the Lower Campus, the Large

Observatory, the Natural Resources Research Institute, and Bagley Classroom.

The University of Minnesota Duluth discharges storm-water to several waters, including Lake

Superior and two trout streams.

Lake SuperiorLake Superior retains the defining characteristics of a lake, but behaves like an inland sea. It

has small tide, busy international ports and 3-quadrillion gallons of water. It contains

3,000,000,000,000,000 gallons (11.4-quadrillion litres) and enough to submerge North and

South America under 1 foot of fresh water. It contains 10% of the world’s fresh surface water

and over half of the water contained in the Great Lakes.

Trout StreamsTrout stream is a stream in which freshwater fish live and which is a good source for

catching trout. “Designated” trout streams are afforded the highest level of protection for

running waters in Minnesota because trout require cold, clear, well oxygenated water to

survive.

Storm water drains directly into local streams and Lake Superior when preventative

measures are not taken. Preventative measures help water soak into the ground; settle,

filter, or biologically remove pollutants; and slow the rate at which storm water enters the

streams.

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WatershedAccording to the Minnesota DNR, watershed is an area of land which surrounds every

channel of a given stream network drains.

The main portion of UMD campus is in three watersheds. They are Chester Creek, Oregon

Creek and the West Branch of Tischer Creek. Chester creek and Tischer creek are

designated trout streams.

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Oregon Creek watershed This Urban Stream can be found flowing through

the University of Minnesota Campus, even

taking shortcuts under buildings.

It enters Lake Superior around 21st Avenue East

Chester Creek watershedExact location: Entering Lake Superior at Leif

Erikson Park,

Chester Creek is a designated trout stream that

flows through the College of St. Scholastica

campus and Chester Bowl Park.

Tischer Creek watershedAlso called Condon Creek, this designated trout

stream flows past Mount Royal shopping centre

before cascading down the Duluth hillside to

Lake Superior.

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University of Minnesota Duluth have more than 60 preventative storm water features in place

to treat the runoff to varying degrees before it discharges to streams.

These features including wet ponds, filtration ponds, modified soils, rain gardens,

hydrodynamic, underground tank, swale, pervious surface, green roof and alternative

plantings.

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WET PONDSWet detention ponds are storm-water control

structures providing both retention and treatment of

contaminated storm water runoff.

There are four ponds in University of Minnesota Duluth campus. They are Fire Hall Pond,

Eric Clarke Pond, Rock Pond and Swenson Science Research Pond. The ponds perform

various function such as to allow sediment to settle out, evapotranspiration, instruction, for

wild rice research and recreational purposes.

The outflows of these ponds are checked at least once a season. Fire Hall Pond and Eric

Clarke had their first dredged in the year of 1980’s and second dredged out to their original

depths in 2002.

Rock Pond outlet is checked more often because of beaver activity the past 5 to 6 years.

The Swenson Science Research Pond is a biological experimental site for students and

faculty that houses stands of wild rice and transient waterfowl. The pond also serves as an

integral part of the storm water handling system.

Eric Clarke Pond

Constructed year: 1965

Located in the Bagley Nature Area on the

northwest corner of St. Marie St. and Kirby Dr.

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Fire Hall Pond


Located near College St. and Kirby Drive.

Rock Pond


Located in the Bagley Nature Area on the

northwest corner of the campus

Swenson Science Research Pond


Located outside Swenson Science Building.

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FILTRATION PONDS

Filtration ponds also known as retention pond. They

are open earthen impoundments designed to retain

storm-water and to infiltrate it into the soil.

The design of a filtration basin is an inlet-settling

basin. It is used to remove coarse materials prior to

flowing into the infiltration basin. The surface of the

infiltration basin in Minnesota Duluth is vegetated.

Infiltration basins is used when there are permeable soils to accept the water, filtration

basins have drain tile systems that collect the filtered water and discharge it to a storm

sewer.

Lot L-3 Filtration Basins

Ianni Hall Volleyball Court

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SWALE

Swales are vegetated, shallow channels with gentle

side-slopes. Treatment occurs as storm-water flows

through the dense vegetation. Removal

mechanisms for pollutants include filtration,

sedimentation, absorption, and infiltration into the

soil profile.

Swales are used to remove sediment and pollutants

that adhere to the sediment.

Glensheen Parking Lot

In 2002, issues such as the erosion problems along shoreline and runoff from parking lot is

detected in the Glensheen Parking Lot of University Minnesota Duluth. Therefore, two

projects were initiated under South St. Louis Soil and Water Conservation District together

with MN Board of Water and Soil funded with matching grants from the Great Lakes

Commission.

The first project the low impact development project. This project modified the parking area

and replaced eroded gullies caused by parking lot runoff with engineered grassy swales,

check dams, and rock chutes, it also includes a bioretention area, and establish the second

project which is the outlet shoreline protection to improve water quality of runoff and reduce

lakeshore bank erosion caused by parking lot runoff.

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Glensheen Plan

Grassed Swale with rock check dams

Water flows from the parking lot into the swale,

where grass and rock check dams cools, slows and

filters the water, and allows some of the water to

infiltrate into the ground. Water that reaches the

lower part of the swale in the photo then flows into

the bioretention area for further treatment.

43

MODIFIED SOILS

Modifying soil surface by adding geo-grids, mesh,

sand or rock to stabilize surface to prevent

ponding.

Modified soils helps to stabilise edges of sidewalks.

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Rock Hill Road

The gravel road surface of Rock Hill Road is replaced with geoweb mesh, and crushed rock

or topsoil mixture to stabilize surface and prevent rutting.

RAIN GARDEN /BIO-RETENTION PONDS

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A rain garden is a planted depression, or low area, that allows rainwater runoff from

impervious surfaces like roofs, driveways, and parking lots to soak in. Rain garden also help

remove pollutants from water before it enters a local stream.

It is a landscaping feature that is planted with native perennial plants and is used to manage

storm-water runoff from impervious surfaces such as roofs, sidewalks, and parking lots.

Lot B UMD Rain Garden

The University of Minnesota Duluth Rain Garden is composed of plantings, a drain tile

system, and a water level control system.

The Lot B UMD Rain Garden was built to help protect Oregon Creek by slowing, cooling and

filtering the runoff water from the adjacent parking lot. It was designed and engineered as a

bioretention pond and is composed of plantings, a drain tile system, and a water level control

system.

A rain garden was built in UMD’s Lot B largest parking lot is due to several reasons. The

main factor is the existing lot shed most of its water to single surface drain, the existing trees

could be preserved and incorporated into the garden, also the located provided a good

opportunity to educate the general public on the benefits of rain gardens. A garden would

enhance the appearance of this site.

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The plating soil in the rain garden is made up of 40% peat and 60% topsoil. The peat helps

absorb more water than normal topsoil would.

The soil treats the water in three major ways:

- It acts as filter with fine pore spaces that retain mineral particles and organic debris.

- Treated by naturally occurring microorganisms in the soil break down organic matter

like oils and greases, bits of dead animal and plant detritus, disease causing

organisms from animal and human wastes, and some anthropogenic contaminants

such as pesticides and petroleum derived compounds which is known as

biodegradation.

- By the capacity of soil particles to chemically absorb heaviest metals, and the

nutrient phosphorus which in excess can stimulate algae growth in downstream

areas and in the near-shore waters of Lake Superior.

The Rain Garden in University Minnesota Duluth is one third acre in size. It handles storm-

water from 2.5 acres of Parking Lot B. It can hold as much as 60,000 US gallons of water.

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1. The UMD Rain Garden is divided into four major plant zones.

Ornamental zone: The burst of colours beyond and to the right of the interpretive signs.

Woodland zone: Directly in front and partially hidden from view

Wetland zone: To the left of the entrance and beyond the grassy mound.

Dry zone: Higher edges of the garden.

2. Grassy Mound

Storm water from the parking lot flows first into the sediment basin, a 12-inch deep circular

trap made of concrete. The sediment basin acts as a first filter for debris and litter. Sediment

sinks to the bottom of the basin and excess water runs over its flat edges to flow over the

wetland zones.

Plants in the wetland zone have high tolerance for water. Native plants are an important part

of the sustainable landscape design. Plants in the UMD Rain Garden are suited for wet area

and can tolerate salts, where it is an important quality when they are filtering snow melt run-

off from the parking lot.

Stepping-stones create a path between the woodland and ornamental zones.

3. Towards the left side of the stepping stones, the sediment basin can be viewed closely.

After returning to the grassy mound via the stepping-stone, the water level structure can be

viewed walking to the left through the woodland zone.

4. Water Level Structure

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The water level structure acts as a dam and regulates the depth of water in the subsurface

of the rain garden. The water level is raised each spring by placing dividers in the structure

to hold back the storm-water runoff within the drain tile.

The drain tile acts as an underground irrigation system for the plants to use during dry

periods. The water level is reduced each fall by removing the divider, to prevent the drain tile

from freezing.

5. Brick Patio

A located which includes a varieties of plants including trees, shrubs, ferns, flowering plants

and grasses. Pussytoes and Virginia Strawberries can be found from the groundcover

together with Bracken Fern and Asters.

HYDRODYNAMIC Hydrodynamic separators are storm-water

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treatment system with small footprints used for removing suspended sediments and

floatables from storm-water runoff in urban area.

.

The UMD campus has installed

hydrodynamic separator in several places include Lot G, Sports Health Centre, Chester Park and Swenson Civil Engineering Centre to separate oils and solids from moving

storm-water by gravity.

UNDERGROUND TANK

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Underground Detention devices are tanks that can take large volumes of storm-water quickly

and then slowly discharge that water back into the storm-water system.

Underground systems are usually more expensive than other systems, but are useful on

small sites.

UMD Library Parking Lot G

Lot G located behind the UMD Library, it produces storm-water that flows to the west branch

of Tischer Creek, which is a designated trout stream.

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The lot was refurbished in 2004 to include an underground “vault” consisting of large

diameter pipes to temporarily store storm-water parking lot runoff. This technology shall

reduce peak flows, reduce the temperature of runoff heated by the asphalt in summer, settle

sediments that can be collected and disposed of properly, and skim oils and grease for

proper disposal.

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PERVIOUS SURFACES

Pervious or permeable pavement is a structural

support surface that allows water to flow through the

material into a subsurface of gravel or rock, and

ultimately into the soil or other post construction

storm-water control.

Pavements can be made of concrete, asphalt,

plastic, or composite materials. They can look like

standard concrete or asphalt pavement, paving block

or even grass.

For the past five years, University of Minnesota Duluth campus have had installed a few

pervious pavement including concrete pavers, recycled rubber pavers and pervious surface.

The places involved in the campus includes Swenson Civil Engineering Loading Deck,

Sports and Health Centre Sidewalk and Chiller Plant Parking Area.

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GREEN ROOF

Green roofs or vegetated roof covers are a thin layer

of living plants growing on top of a roof. A green roof

is not a collection of potted to decorate a roof space

but rather an extension of a conventional roof which

involves installation of a layered system of

membranes, substrate and plants.

Bagley Outdoor Classroom

The Bagley Outdoor Classroom demonstrates leadership in energy efficiency, renewable

energy, wastewater treatment, storm-water management, passive heating, natural

ventilation, water efficiency, local and renewable materials, and a healthy indoor

environment.

Energy efficiency and conservation was an area of focus during design and construction of

the Bagley Outdoor Classroom. The design is expected to reduce the energy needs of the

building by 90% and was built to meet standards for Passivhaus certification.

For storm-water management, the roof of the building uses multiple methods in its

contribution to the building’s efficiency.

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The lower tier is a green roof that helps to insulate the building as well as curb storm-water

runoff, while the upper section is painted white to reflect excess sunlight.

A view of the partial green roof from top of a stairwell in Civil Engineering.

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ALTERNATIVE PLANTINGS

Alternative plantings can be found throughout

campus. A majority of these plantings are in areas

that would hold sod, a high maintenance method of

landscaping. Low maintenance alternative plantings

help to diversify the appearance of the campus as

well as reduce carbon footprint.

Close-up of native flowers.

College Street Rain Garden

Close-up of native grasses, along University Drive

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Sunflowers outside of the Kathryn A. Martin Library

Wildflowers along the University Drive

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Storm Water Pollution Prevention Program

University of Minnesota Duluth has developed a Storm Water Pollution Prevention Program

(SWPPP) to reduce the quantity and to improve the quality of storm water runoff. This

program is legally approved by the Minnesota pollution Control Agency, which act on behalf

of the U.S. Environmental Protection agency to enforce the federal Clean Water Act.

The Storm Water Pollution Prevention Program (SWPPP) require six minimum control

measures, including

- Public Education and Outreach

- Public Involvement and Participation

- Illicit Discharge Detection and Elimination

- Construction Storm Water Runoff Control

- Post Construction Storm Water

- Pollution Prevention and Good Housekeeping

In order to reduce the impacts on the campus itself from receiving waters to the maximum

extent practicable (MEP) for each of the six minimum control measures, the University of

Minnesota has established a set of best management practices (BMPs). These BMPs form

the framework for the SWPPP.

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Public Education and Outreach

The University of Minnesota Duluth is uniquely equipped to provide educational storm water

resources for its campus and greater community. The Natural Resources Research Institute,

Minnesota Sea Grant, and University of Minnesota Extension, as well as UMD colleges,

schools, and departments, are committed to supporting the UMD Storm Water Pollution

Prevention Program. All storm water in Duluth ultimately ends in Lake Superior, hence all

citizens have the responsibility to protect this pristine water and by doing so can protect the

source of drinking water. UMD has been a strong supporter of this philosophy from the start

and partnered with the City of Duluth and other concerned organizations and MS4s to create

the Regional Storm Water Protection Team (RSPT) in 2003.

The mission of RSPT is to protect and enhance the region’s shared water resources through

storm water pollution prevention by providing coordinated educational programs and

technical assistance. RSPT now consists of 25 organizations, including all of the region’s

regulated MS4s. They have meetings monthly in order to address common storm water

issues.

UMD Educational Materials:• Illicit Discharge Poster (2015)

• Illicit Discharge Quiz Slideshow (2013)

UMD Educational Signage:• Glensheen Storm Water Projects• Rain Garden Sign 1• Rain Garden Sign 2• Bagley Outdoor Classroom• Lawrence A. Ianni Hall

Additional Resources:• Homeowner Stormwater Factsheets

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Illicit Discharge Poster (2015)

Public Involvement and Participation

The University of Minnesota Duluth (UMD) welcomes involvement from the public. For the

purpose of the Storm Water Pollution Prevention Program (SWPPP), the UMD ‘public’ is

defined as employees, students, and contractors that make up the campus community. UMD

believes that an involved community is more likely to understand the need for, and thus

support the success of a storm water program. They strongly encourage the involvement in

its creation, implementation, and evaluation.

Ideas:• Include storm-water information to be taught in classes. Information regarding their storm

water system and watershed will be provided to the public. Besides that, UMD is willing to

put effort in suggesting possible class projects, and talk about storm water and other water

pollution issues with the public.

• Welcome the assistance in reviewing their best management practices. As part of the

Storm Water Protection Program (SWPPP), UMD continue to develop written procedures.

They would appreciate the input of anyone with special knowledge or concern in a particular

area.

• Assistance in hands-on clean ups and/or special projects. Everybody can help with projects

such as the annual Campus Clean Sweep, held in April during Earth Day celebrations.

• Membership for Storm Water Steering Committee. Each January, UMD assemble a storm

water committee to assist with their storm water program throughout the year. Anyone

interested can join.

• Others. Anyone can sound out their opinions, ideas or useful suggestions to them

if possible.

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Illicit Discharge Detection and Elimination

What is an Illicit Discharge?Federal regulations define illicit discharge as ‘… any discharge to the municipal separate

storm sewer system (MS4) that is not composed entirely of storm water…’ with some

exceptions.

These discharges are considered ‘illicit’ because MS4s are not designed to accept or

discharge such non-storm water wastes. It is important to note that illicit does not necessarily

mean illegal.

Illicit discharges can come from improperly connected/maintained sanitary sewers,

dewatering construction sites, draining swimming pools, draining construction ponds,

improper equipment/vehicle washing, improper vehicle machinery maintenance (drippings)

as well as improper disposal of items such as pet waste, cigarette butts, oils, paints, and

trash.

Is Storm Water Treated?Storm water is not treated in the traditional sense. It is important to note that storm sewer

water is different than sanitary sewer waste. Sanitary waste is the modern technical name

for sewage, the combined wastewater from all toilets, sinks, shower/tubs, floor drains, etc.

These wastes are treated at a wastewater treatment plant to attain a set of legally specified

water quality standards before being discharged into natural waters. Duluth’s (including all of

UMD) wastewater is treated at the Western Lake Superior Sanitary District (WLSSD) facility.

Storm water from UMD drains directly into local streams and Lake Superior if preventive

measures are not taken. There are more than 60 preventative storm water features in

campus such as rain gardens, pervious surfaces, green roofs, filtration ponds, and

alternative plantings.

What Types of Non Storm Water Discharges Are Okay?Non storm water discharges can include ‘water line flushing, landscape irrigation, diverted

stream flows, rising ground waters, uncontaminated ground water infiltration, and

uncontaminated potable water sources, foundation drains, air conditioning condensation,

irrigation water, springs, water from crawl space pumps, footing drains, lawn watering,

individual residential car washing, flows from riparian habitats and wetlands, de-chlorinated

swimming pool discharges, and street wash water’.

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What Steps Does UMD Take to Detect and Eliminate Illicit Discharges?It is important to know the system and its surroundings in order to identify illicit discharges.

For this reason, UMD has developed and continue to maintain storm sewer system maps.

Physical observations such as odour, colour, and condition are reviewed to locate potential

illicit discharges during storm water outlet inspections. Programs like the UMD Spill

Prevention Control and Countermeasures Plan, U of M Chemical Hygiene Plan, as well as

the state-of-the-art integrated waste management facility at the Twin Cities campus identify

potential illicit discharges. A building-by-building document that provides record of storm

water and sanitary inspections is in the process of completion. The objective of this

document is to determine potential interconnections for the buildings.

Construction Site Runoff ControlAccording to the reliable data on Construction Site Runoff Control, “Sediment runoff rates

from construction sites are typically ten to twenty times greater than those of agricultural

lands, and one thousand to two thousand times greater than those of forest lands. In a short

period of time, construction sites can contribute more sediment to streams than can be

deposited naturally during several decades. The resulting situation, and the contribution of

other pollutants can cause major damage to our nation’s waters.”

Figure above (cause) shows contractor flushes newly installed hydrant near an unprotected catch basin

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Figure above (effect) shows the sediment plumb in a nearby trout stream

UMD construction projects are required to have provisional and sediment control measures

incorporated in the design. The construction documents must identify relevant details as well

as contractor execution and inspection responsibilities.

Sediment can be controlled through the use of multiple application. Erosion can be

prevented using existing vegetation and geotextiles.

Post Construction Storm WaterIn areas undergoing new development or redevelopment post-construction storm water

management is needed because runoff from these areas has brought significantly impact to

the receiving water bodies. Many studies indicate that prior planning and design for the

minimization of pollutants in post-construction storm water discharges is the most cost-

effective approach to storm water quality management.”

During design, the potential increase in type and quantity of pollutants in storm water runoff

and the potential increase in the quantity of water delivered to the water body during storms

should be addressed to the maximum extent practicable.

The University of Minnesota Duluth has completed numerous post-construction storm water

management improvement projects since the program began in 2003. There are now more

than 60 storm water management features across campus.

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Examples of these post-construction storm water projects include:

• Redesigning pond outlet structures to decrease the temperature of water discharged to

Tischer Creek (one of Duluth’s 16 sensitive trout streams).

• Construction of a low impact development storm water demonstration project consisting of

grassy swales, rock check dams, and bio retention filters at Glensheen Mansion on the

shoreline of Lake Superior.

• A one-third-acre demonstration rain garden along College Street with the capacity to

receive and filter 2.5 acres of storm water runoff from an existing parking lot that previously

discharged to Oregon Creek.

• A green roof on Bagley Outdoor Classroom designed to reduce storm water inputs to

Tischer Creek.

• A sand pit volleyball court to treat the storm water from Lawrence A. Ianni Hall’s roof and

parking lot.

Pollution Prevention and Good Housekeeping The University of Minnesota Duluth is known of setting an example for preventing storm

water pollution in its maintenance practices. The University is establishing a system of good

housekeeping practices that recognize that the campus operates in an urban area.

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POSSIBLE PROBLEMS TO THE SYSTEMGreen RoofTo have a good and sustainable green roof, there must be work to ensure it remains a

thriving atmosphere. As most problems with green roof are mainly maintenance and plant

selection. For maintenance, the green roof must be taken as a garden and as such, it will

require watering, feeding and weeding.

As the green roof provide far greater benefits for implementing one and as such, maintaining

it must have serious consideration. There’s a reason green roofs are a common sight around

other European countries as it is beautiful and also provides loads of benefits.

Plant selection is a critical factor in success of a green roof as without a good plant selection,

maintaining the green roof would cost greatly for consistent maintenance. As if chosen the

wrong plant for the green roof, the plant would not be able to survive in the climate for the

local area and perform properly for the green roof.

Sample of Dead Plant on Green Roof

UndergroundThe few major possible problems would be allowing direct recharge of groundwater from

underground Storm-water storage units. Allowing it is not usually recommended due to it

being unhealthy and also unhygienic. Exceptions to be made highly depends on the type of

soil there.

From the problem of allowing direct recharge of groundwater from underground Storm-water

storage unit, it also creates another problem which is that the infiltration system underground

will be affected and also the movement of water will be restricted.

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SwalesGenerally, the individual grass swales are unable to treat a very large drainage area size. As

well as the grass swales do not appear to be effective enough at reducing the bacteria levels

in the storm-water runoff. This also due to the fact that the wet swales can be a nuisance by

failing to stop mosquito breeding there.

The grass swales if not properly designed, it will cause numerous problem mainly that the

grass swales will not be as effective against pollutant removal around the area. Mainly it is

missing a thick vegetative cover for its proper function to assist.

Polluted SwalesPondThis system also has a number of possible problems and requires several modifications to

better overcome it. One of the main possible problem would be the effectiveness of pollutant

removal. This is mainly due to the settling area being relatively small as it will be harder to

separate the heavier sediments with the lighter sediment. Hence, not being able to fully clear

the pond.

Aside from that, there are still problems related to impede flow and trap the remaining

pollutants that enters the water. Mainly that there is nothing aiding the removal of pollutant

that is creating a possible problem in the future.

Pond Infiltration Problem

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RECCOMMENDATIONS FOR FUTURE IMPROVEMENTGreen RoofGreen roof is designed to soak up water and remove contaminants in the water during storm

events, therefore the species that are able to accumulate nutrients and use water effectively is

recommended. The herbaceous or shrubby species are the best choices due to their high water

requirement. With herbaceous plants as the interface, the water landed on the substrate may

move more effectively and back into the atmosphere. In addition, higher levels of water loss

provide greater water movement and increase localised cooling of the surrounding environment.

One of the examples of herbaceous species is Tulbaghia Violacea. This is a popular roof plant

that can tolerate prolonged drought and flourishes with regular watering.

Another example of shrubby species is Leonotis Leonurus. Leonotis Leonurus is an excellent

plant for attracting wildlife as the flowers profuse copious nectar which attracts birds, bees and

butterflies.

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UndergroundThe characteristics of the soil of the site must be studied before the installation of underground

storage system. Only soils which are suitable for infiltration able to allow a direct recharge of

groundwater from underground storage units. Acceptable soils for underground system include

sand, sandy loam and loam. Sandy soils are permeable, which means that water can infiltrate

through them easily and rapidly. Soils with lots of clay or silt should be avoided because it

restricts the movement of water.

Sand

Sandy loam

Loam

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SwalesTo enhance stabilization and filtration of the swales, check dams can be constructed with the

swales. Check dams are low barriers recommended for swales with longitudinal slopes greater

than 3% to prevent erosion and promote sedimentation by decreasing runoff volume, rate, and

velocity. Besides that, check dams also provide a good removal of pollutants and they require

less maintenance. Swales with check dams are much more effective at mitigating runoff

quantity and quality than those without. Check dams can be constructed from a variety of

materials such as natural wood, concrete and stone.

Grassed swale with rock check

Todd Campbell, MNDOT-Duluth

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PondsThere are several measures can be implemented to the ponds to increase the pond’s pollutant

removal effectiveness.

The addition of a sediment forebay of 4 to 6 feet deep as shown in the figure above can be

added to the pond in order to increase the settling area for sediments. By incorporating a

separate pond or also known as the sediment forebay, sediments can settle out before reaching

the main detention pond will localize sediment deposition where sediments which are denser

will pass through the sediment forebay and drop out of suspension as runoff while sediments

which are less dense will settle out as runoff and retained in the permanent pool. In addition, the

bottom of forebay may be in concrete to make sediment removal easier.

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Second improvements that can be made to the pond is the construction of shallow ledges along

the edge of the permanent pool as they can perform a function of establishing aquatic plants

that prevents the entering of flow and trapped pollutants. The aquatic plants perform various

function. Besides providing biological uptake, it also stabilizes side slopes, serves as wildlife

habitat, catches temporary trash and debris and also discourages entrance into the pond which

allow easy access to the permanent pool to aid in maintenance.

Another modification can be made to the permanent pool is to install an anti-seep collars on the

outlet barrel to reduce the potential for pipe failure. A bottom drain pipe should be able to drain

the permanent pool in 24 hours. Besides, the installation of riprap or splash pad can be placed

at outlet to prevent scouring and erosion.

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LEARNING FROM THE GROUP PROJECTThis project is a study on building services system with the selected topic which was storm-

water management system. We are required to have research study based on the storm-water

management system supported by at least one case study. In group of 6 students, we have

chosen to do our research case study on the Storm-water Management System in University of

Minnesota Duluth.

After completing this project, we all had a clearer and better understanding towards the building

services technology and the management system. We were also able to develop a core

understanding towards the materials and current applications used in the industry. We were

also able to find out that Storm-water management system can be used and maintained quite

well with not as much as cost from what others would think. The Storm-water management

system really is something that would highly benefit us as it assists and solves our water

problems partially. The Storm-water Management System brings a lot of benefits for us, but also

some disadvantages and potential problems that some can and cannot be avoided.

By completing this assignment, we are all now able to identify the application, system,

installation process, benefits, potential problems and how to solve it. We are also able to explain

the relevant information that related to the Storm-water Management to the related case study

which was the Storm-water Management System in University of Minnesota Duluth.

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APPENDICES

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Infographic poster of Glensheen Storm Water Projects

Infographic Poster of Basic Requirements of a Storm Water Pollution Prevention Plan

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Infographic Poster of Installation Guide for Channel Drainage

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Presentations & Public Speaking

Sustainable Storm-water Management Report