GEOG 442 Day 12: Infrastructure Planning. 2 Water, Sewer and Stormwater Systems n Municipal water and sewer systems are expensive, and thus have to be

GEOG 442GEOG 442

Day 12Day 12: Infrastructure Planning: Infrastructure Planning

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Water, Sewer and Stormwater SystemsWater, Sewer and Stormwater Systems

Municipal water and sewer systems are expensive, and Municipal water and sewer systems are expensive, and thus have to be planned carefully. They are essential thus have to be planned carefully. They are essential preconditions for new urban development, and can also preconditions for new urban development, and can also and often do stimulate such development once in place.and often do stimulate such development once in place.

Demand for land uses has to be coordinated with Demand for land uses has to be coordinated with infrastructure provision (i.e. location, type, quality, use infrastructure provision (i.e. location, type, quality, use and capacity).and capacity).

Their capacity thresholds have to be respected or they Their capacity thresholds have to be respected or they will break down.will break down.

For decades, these systems were supplied free to For decades, these systems were supplied free to developers, but now there is trend towards cost developers, but now there is trend towards cost recovery though not on an equitable basis.recovery though not on an equitable basis.

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Water Supply SystemsWater Supply Systems

Two types of water, though most municipal systems do Two types of water, though most municipal systems do not distinguish: not distinguish: potablepotable (for drinking) and (for drinking) and non-potablenon-potable (for agricultural and industrial use). A potable system (for agricultural and industrial use). A potable system addresses addresses acquisitionacquisition, , treatmentreatment and t and deliverydelivery..

The source of potable water is either The source of potable water is either surface watersurface water or an or an underground aquiferunderground aquifer. (Two million Canadian urban . (Two million Canadian urban residents rely on groundwater.) Water is treated for use residents rely on groundwater.) Water is treated for use by by physicalphysical (filtration and sedimentation) and (filtration and sedimentation) and chemicalchemical means (chlorination and flouridation; sometimes means (chlorination and flouridation; sometimes ozonation).ozonation).

The water is then stored underground or above ground The water is then stored underground or above ground for peak use and to maintain pressure (“head”).for peak use and to maintain pressure (“head”).

Water is delivered through a branch or a loop system of Water is delivered through a branch or a loop system of pipes, the latter providing more consistent pressure.pipes, the latter providing more consistent pressure.

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Different land uses generate different levels of demand. To Different land uses generate different levels of demand. To meet this demand, we need to know the system’s yield meet this demand, we need to know the system’s yield capacity, storage capacity, location of mains, and capacity, storage capacity, location of mains, and distribution pipe sizes and locations. We also need to know distribution pipe sizes and locations. We also need to know current and projected demand, consumer preferences, and current and projected demand, consumer preferences, and government policies and regulations. Overall issues government policies and regulations. Overall issues concern quantity, quality, and pressure. What are desirable concern quantity, quality, and pressure. What are desirable and undesirable qualities possessed by potable water?and undesirable qualities possessed by potable water?

The design standard for municipal water in North America is The design standard for municipal water in North America is 150-300 gallons (570-1140 litres) per person. In Canada, 150-300 gallons (570-1140 litres) per person. In Canada, actual consumption is 650 litres. 35% or higher is for actual consumption is 650 litres. 35% or higher is for domestic use, 50% for non-domestic and public uses, and domestic use, 50% for non-domestic and public uses, and 15% unaccounted for losses and leaks. Older systems lose 15% unaccounted for losses and leaks. Older systems lose up to 50% in transit.up to 50% in transit.

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Water quality standards are set by the province, but Water quality standards are set by the province, but usually accord with the Canadian Drinking Water usually accord with the Canadian Drinking Water Standards. 30 lbs. per square inch (psi) is needed Standards. 30 lbs. per square inch (psi) is needed for fire-fighting, and 50-75 is optimal for domestic for fire-fighting, and 50-75 is optimal for domestic purposes.purposes.

Municipal water systems are economically justified Municipal water systems are economically justified at 1000 persons per square mile or at 0.6 dwellings at 1000 persons per square mile or at 0.6 dwellings per acre gross. While urban redevelopment is per acre gross. While urban redevelopment is desirable from an infrastructural efficiency desirable from an infrastructural efficiency standpoint, if the system is too old the extra demand standpoint, if the system is too old the extra demand could cause pipe rupture.could cause pipe rupture.

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There is an increasing trend towards There is an increasing trend towards demand demand managementmanagement instead of increasing supply. instead of increasing supply. What are some of the ways of decreasing or What are some of the ways of decreasing or stabilizing per capita demand?stabilizing per capita demand?

Another challenge for supply is when sources Another challenge for supply is when sources are compromised. Can you think of are compromised. Can you think of examples, and cite the kinds of things that examples, and cite the kinds of things that can compromise water sources?can compromise water sources?

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Walkerton Water Tragedy (2000)Walkerton Water Tragedy (2000)

Walkerton criminal charges met with angerWalkerton criminal charges met with anger

WALKERTON -- At a news conference marked by angry WALKERTON -- At a news conference marked by angry outbursts from residents, Ontario Provincial Police outbursts from residents, Ontario Provincial Police announced yesterday they have charged the two announced yesterday they have charged the two brothers at the centre of the Walkerton tainted water brothers at the centre of the Walkerton tainted water tragedy. tragedy. Stan Koebel, manager of the Walkerton Public Utilities Stan Koebel, manager of the Walkerton Public Utilities Commission when the E. coli disaster hit in 2000, faces Commission when the E. coli disaster hit in 2000, faces seven criminal charges. seven criminal charges. His brother, Frank, PUC foreman at the time, faces five His brother, Frank, PUC foreman at the time, faces five criminal charges.criminal charges.

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Walkerton Water Tragedy (2000)Walkerton Water Tragedy (2000)

Seven people died and more than 2,000 were Seven people died and more than 2,000 were sickened by E. coli contamination of sickened by E. coli contamination of Walkerton's water system in May 2000. Walkerton's water system in May 2000. "After a very extensive investigation, the OPP "After a very extensive investigation, the OPP investigators have determined these are the investigators have determined these are the charges that are supported by the evidence," charges that are supported by the evidence," acting OPP Det. Supt. Paul Chaytor told a acting OPP Det. Supt. Paul Chaytor told a news conference packed with media and news conference packed with media and about a dozen Walkerton residents.about a dozen Walkerton residents.

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Municipal Wastewater SystemsMunicipal Wastewater Systems

As of 1994, 75% of Canada’s population was As of 1994, 75% of Canada’s population was serviced by municipal wastewater treatment serviced by municipal wastewater treatment systems. These operate mostly on the basis systems. These operate mostly on the basis on gravity-fed collection pipes.on gravity-fed collection pipes.

Once collected the sewage is treated Once collected the sewage is treated according to one or more of the following according to one or more of the following standards: standards: primaryprimary, , secondarysecondary, or , or tertiarytertiary..

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Primary treatment involves screening and Primary treatment involves screening and sedimenting techniques for removing solids sedimenting techniques for removing solids and organics.and organics.

Secondary treatment involves using biological Secondary treatment involves using biological means to digest the waste, andmeans to digest the waste, and

Tertiary treatment involves using bio-chemical Tertiary treatment involves using bio-chemical means to remove phosphorus and nitrogen means to remove phosphorus and nitrogen that contribute to that contribute to eutrophicationeutrophication..

Some communities are turning bio-solids into Some communities are turning bio-solids into fertilizer.fertilizer.

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Diagram of Sewage TreatmentDiagram of Sewage Treatment

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In 1994, 39% of the population with In 1994, 39% of the population with municipal systems were receiving primary municipal systems were receiving primary treatment, 31% secondary, and 39% with treatment, 31% secondary, and 39% with tertiary. There are a few significant tertiary. There are a few significant municipalities that have no treatment at all. municipalities that have no treatment at all. Can you name them?Can you name them?

Different land uses place different demands Different land uses place different demands on the sewage treatment system, including on the sewage treatment system, including in relation to peak demand. Systems, once in relation to peak demand. Systems, once put in place, offer little flexibility. put in place, offer little flexibility.

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For planning purposes, one needs to know For planning purposes, one needs to know the location, size, and age of the collection the location, size, and age of the collection and treatment components, current demand and treatment components, current demand and remaining capacity, characteristics of and remaining capacity, characteristics of the waste stream, and policy and the waste stream, and policy and regulations regarding effluent and sludge regulations regarding effluent and sludge disposal. (In some cases, the sludge is disposal. (In some cases, the sludge is landfilled; in other cases, it is used as a soil landfilled; in other cases, it is used as a soil conditioner.)conditioner.)

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Wastewater SystemsWastewater Systems

Between 65% and 85% of municipal water Between 65% and 85% of municipal water supply is cycled into the wastewater (sewer) supply is cycled into the wastewater (sewer) system. The U.S. EPA suggests an expected system. The U.S. EPA suggests an expected per capita production of 100-125 gallons – per capita production of 100-125 gallons – 60% domestic, and the remainder 60% domestic, and the remainder commercial, industrial, and institutional. One commercial, industrial, and institutional. One can also calculate expected volumes based can also calculate expected volumes based on population density and per capita on population density and per capita production rates (see table on p. 161 for production rates (see table on p. 161 for residential wastewater flows).residential wastewater flows).

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A sewerage impact analysis would look at A sewerage impact analysis would look at location and amount of projected location and amount of projected development, the possible need for new development, the possible need for new treatment methods, and new regulatory treatment methods, and new regulatory standards. This would help determine service standards. This would help determine service areas, trunk extensions, and technologies to areas, trunk extensions, and technologies to be used. Increasingly, developers are being be used. Increasingly, developers are being required to pay for new wastewater systems required to pay for new wastewater systems through development charges (DCCs or through development charges (DCCs or DCLs).DCLs).

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Isolated developments can use self-contained Isolated developments can use self-contained communal systems. One example, both of a self-communal systems. One example, both of a self-contained and of an alternative sewage treatment contained and of an alternative sewage treatment system, is the solar aquatics system in a trailer park in system, is the solar aquatics system in a trailer park in Errington.Errington.

In rural areas, the tendency is to rely on septic systems In rural areas, the tendency is to rely on septic systems (bacterial action and tile beds to percolate the effluent (bacterial action and tile beds to percolate the effluent into the soil). Depending on soil conditions, the lots into the soil). Depending on soil conditions, the lots have to be big enough to ensure separation between have to be big enough to ensure separation between the house, well, and septic bed – not to mention the house, well, and septic bed – not to mention neighbours’ wells. In extreme cases, this could be one neighbours’ wells. In extreme cases, this could be one acre configured as follows: 150 feet by 300 (50 metres acre configured as follows: 150 feet by 300 (50 metres by 100).by 100).

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Diagram of Septic SystemDiagram of Septic System

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Solar Aquatic Sewage SystemSolar Aquatic Sewage System

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Stormwater ManagementStormwater Management

The hydrological cycle consists of:The hydrological cycle consists of: precipitationprecipitation infiltrationinfiltration transpirationtranspiration evaporation, andevaporation, and run-off/ stream flowrun-off/ stream flowThe cycle is very much affected by human The cycle is very much affected by human

activities and structures, especially the activities and structures, especially the urbanization process. Why is this so?urbanization process. Why is this so?

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Urban development increases the amount of Urban development increases the amount of impervious surfaces (roofs, roads, and parking impervious surfaces (roofs, roads, and parking lots) and reduces vegetation. This reduces lots) and reduces vegetation. This reduces infiltration and evapo-transpiration and increases infiltration and evapo-transpiration and increases the speed and volume of run-off, which can lead to the speed and volume of run-off, which can lead to erosion and flooding.erosion and flooding.

The run-off picks up pollutants from urban The run-off picks up pollutants from urban surfaces, such as roads, and discharges them into surfaces, such as roads, and discharges them into receiving waters, unless they are treated by receiving waters, unless they are treated by various means. Some pollutants are deliberately various means. Some pollutants are deliberately dumped into storm sewers. This kind of “diffuse” dumped into storm sewers. This kind of “diffuse” pollution is called pollution is called non-point sourcenon-point source pollution. pollution.

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Urban run-off often contains organic Urban run-off often contains organic matter (e.g. feces), bacteria, dust and matter (e.g. feces), bacteria, dust and dirt, nitrogen, phosphorus, chlorides dirt, nitrogen, phosphorus, chlorides (from road salt), metals, oil and grease, (from road salt), metals, oil and grease, and much more. It can and often does and much more. It can and often does have a very negative impact on fish and have a very negative impact on fish and fish habitat, water supply, and recreation fish habitat, water supply, and recreation areas, while adding sediments and algae areas, while adding sediments and algae to rivers and lakes.to rivers and lakes.

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A stormwater system consists of surfaces A stormwater system consists of surfaces and channels and/or underground pipes. and channels and/or underground pipes. In some municipalities there are In some municipalities there are combined storm and sanitary systems combined storm and sanitary systems where stormwater is channeled to where stormwater is channeled to sewage treatment plants, but in the event sewage treatment plants, but in the event of “major weather events,” the sewage of “major weather events,” the sewage pipes overflow into storm sewers and pipes overflow into storm sewers and discharge raw sewage into receiving discharge raw sewage into receiving waters.waters.

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To calculate appropriate channels and conduits To calculate appropriate channels and conduits and flood prevention measures, one must and flood prevention measures, one must know how much run-off can be expected. know how much run-off can be expected. There are two methods for doing this:There are two methods for doing this:

The The rationalrational method examines the amount of method examines the amount of run-off for a given land use (the run-off for a given land use (the coefficientcoefficient [C]) [C]) – see p. 162 for a list – and multiplies that by – see p. 162 for a list – and multiplies that by the the intensityintensity [I] of rainfall and the size of the [I] of rainfall and the size of the area area [A] to be drained. [A] to be drained.

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This is also calculated based on the This is also calculated based on the biggest likely storm event for a given period biggest likely storm event for a given period – anywhere between two and ten years, – anywhere between two and ten years, depending on the property value and depending on the property value and liability issues associated with the area.liability issues associated with the area.

The The hydrographhydrograph method is best used for method is best used for flood control and retention/ detention flood control and retention/ detention measures where one looks at flow rates at measures where one looks at flow rates at key “points of interest”.key “points of interest”.

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There is a new trend towards requiring There is a new trend towards requiring developers to employ best management developers to employ best management practices (BMPs) to create practices (BMPs) to create zero discharge zero discharge increaseincrease with new developments. This with new developments. This means ensuring that baseline run-off means ensuring that baseline run-off conditions are not made worse in any way.conditions are not made worse in any way.

There are a number of ways of managing There are a number of ways of managing run-off in more proactive ways:run-off in more proactive ways:

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Example of Alternative Stormwater Example of Alternative Stormwater Management SystemManagement System

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Permeable ‘Country Lane’ in Permeable ‘Country Lane’ in VancouverVancouver

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GEOG 442 Day 12: Infrastructure Planning. 2 Water, Sewer and Stormwater Systems n Municipal water and sewer systems are expensive, and thus have to be