Storm Water Management Plan - The City of Spruce Grove

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Storm Water Management Plan - The City of Spruce Grove

Storm Water Management

Design

Construction

Maintenance


Standards and Guidelines

Legislation and guidelines from Federal, Provincial, and Municipal levels

of government affect the design or construction of stormwater

management facilities within the Province of Alberta.

•Canada and Alberta Health Acts

•Canada Fisheries Act

•Alberta Water Act

•Alberta Environmental Protection and

Enhancement Act

•Alberta Environmental Protection –

Stormwater Management Guidelines

•Big Lake Management Plan

•Alberta Municipal Government Act

City of Spruce Grove Master Drainage Plan

•Development Agreements

Stormwater Management

Systems (SWMS)


Goals of SWMS

1. Designed so that the post-development peak discharge rate and

pollutant loadings to receiving watercourses are the same as predevelopment

values.

2. Flow control involves managing both flow rate and intensity of storm

water.

3. Increasing development leads to higher amounts of impervious

surfaces.

Stormwater Management

Systems (SWMS)


City’s Approach

1. On-site flow control on several private non-residential

and multi-family sites.

Example:

Superstore, Wal-Mart Mart, TLC & Grove Seniors

Village pre-development values.

Stormwater Management

Systems (SWMS)


City’s Approach

2. Subdivision SWMFs wet or dry ponds (1-2 quarter

sections) constructed by developers on an ownership

area or a shared ownership basis.

Example: Deer Park, Westgrove, Hilldowns

Stormwater Management

Systems (SWMS)


City’s Approach

3. Citywide SWMFs exist or proposed dry, wet or wetland

facilities designed and constructed to manage flow rates

from large portions of the existing and future areas

within the City.

Example:

SWMF at Campsite Road

Century Road North Pond

Proposed King Street facility (2006)

Proposed Jesperdale facility (2006-07)

Stormwater Management

Systems (SWMS)


City’s goal

25L/ 2.5 L/sec/ha /h

This predevelopment rate was determined in the City’s

Master Drainage study (1998) and confirmed in the Big

Lake Regional study completed in 2005.

Stormwater Management

Systems (SWMS)


Removal of Pollutants

Urbanized areas generate

large quantities of pollutants

during storm or snowmelt

events

SWMSs can be constructed

to remove these pollutants.

Stormwater Management

Systems (SWMS)


Removal of Pollutants

The City proposes to remove potential pollutants as

follows:

1. Construct three major wetland SWMF for existing

watercourses to drain

King Street t Campsite Jesperdale

2. Continue to include water quality requirements in future

development agreements

Stormwater Management

Systems (SWMS)


Removal of Sedimentation

Removal of sedimentation is usually by gravity

Properly designed, constructed

and maintained stormwater

infrastructure can effectively

remove a wide range of

pollutants from urban runoff.

Pollutants become absorbed or

attached to solids entering the

storm system.

SWMSs such as ponds, constructed wetlands and catchbasin

sump ppits effectively can achieve this.

Stormwater Management

Systems (SWMS)


Source Reduction - Total Suspended Solids (TSS)

• TSS come from the eroding stream banks, erosion from construction

sites and dirt from streets, parking lots.

• excessive TSS can cloud and negatively effect watercourses

Stormwater Management

Systems (SWMS)


Source Reduction

DFO dictated t d City Goal:

Reduce 85% of all Total Suspended Solids (TSS) for a

particle size of 75μm or less (silts and clays)

Stormwater Management

Systems (SWMS)


Source Removal of Pollutants

Removal of these contaminants prior to entering SW system:

•Limiting applications of fertilizers, pesticides and

herbicides

•Periodic street sweeping to remove trash, litter,

and particulates from streets

•Periodic cleaning of catch basins

•Use of Oil/Water Separators as condition of

development approval

Oil/Water Separator

•Elimination of improper dumping of used oil,

antifreeze, household cleaners, paint, etc. into

storm drains.

Stormwater Management

Systems (SWMS)


Design of SWMS

Underground piped system

•Convey the 1.5 year run-off event

•1:100 year run-off event – flow overland

•CB’s to be designed with a minimum flow of 600mm sump pit

Stormwater Management

Systems (SWMS)


Design of SWMS

Storm Water Management Facilities (SWMF)

Dry Ponds

•Should only be used when downstream water quality system is in

place

•Designed to store the 1:100 runoff event to 2.5l/sec/ha

The maximum water level should be below the adjacent footing levels

•Must be landscaped and constructed to restrict erosion

Stormwater Management

Systems (SWMS)


Design of SWMS

Storm Water Management Facilities (SWMF)

Wet Ponds

•Designed to store the 1:100 runoff event to 2.5l/sec/ha

The maximum water level should be below the adjacent footing levels

•May require downstream water quality system

•Minimum freeboard of 0.5m

•Landscaped and constructed to restrict erosion

•Warning signs should be posted

Stormwater Management

Systems (SWMS)


Design of SWMS

Storm Water Management Facilities (SWMF)

Constructed Wetlands

•Designed to store the 1:100 runoff event to 2.5l/sec/ha

•10% of the wetland surface area should be 1.5 – 2.0 m deep forebay

•Active water of 0.3 m with 1 m zones

•Landscaped and constructed to restrict erosion

•Warning signs should be posted

Stormwater Management

Systems (SWMS)


Control During Construction

Erosion and sedimentation concerns:

• Mud tracking

• Silt and debris washed into the

drainage system

• Silt and debris transported to

receiving i watercourses by surface

runoff and the sewer

Erosion and sediment control

practices can be employed.

• Wind blown dust

Stormwater Management

Systems (SWMS)


Control During Construction

When sewers or drainage courses have been constructed or are

existing, measures should be undertaken to ensure sediment and

debris does not get into the municipal system.

1. Location of stockpiles

2. All construction vehicles should

leave the site at a designated

point or points

3. Placement of temporary weirs

or silt curtains or fences

4. Dust Control

5. Removal of sediments and

debris

Stormwater Management

Systems (SWMS)


Storm Sewer Infrastructure Inventory

The inventory of storm sewer infrastructure within the corporate limits is

estimated as follows:

Public

Private

1. Sewer Mains (km) 60 5

2. Catchbasin leads (km) 30 2

3. Manholes (ea) 1200 200

4. Catchbasins (ea) 1300 200

5. Stormceptor manholes (ea) 0 5

6. Orifice controls (ea) 20 10

7. On-site flow control facilities (ea) 0 10

8. Subdivision SWMFs (ea/ha) 20/ 50 N/A

9. City wide SWMF (ea/ha) 4/35 N/A

10. Ditch / Watercourse (km) 30 2

11. Culverts (ea / km) 100 100

Stormwater Management

Systems (SWMS)


Maintenance of SWMF

4 types of maintenance:

Reactive

Periodic

Predictive

Proactive

Stormwater Management

Systems (SWMS)


Life-Cycle Maintenance

Remedial maintenance (often called remedial or minor

construction) fixes what's there, restoring it as nearly as possible to its

original i capacity or condition.

Capital construction involves planning, design, and

replacement of the system, usually resizing it for current or future

conditions or improved design criteria standards.

Stormwater Management

Systems (SWMS)


Maintenance Activities

Street cleaning is completed as follows:

Local and minor collector residential, industrial and

Hwy 16A

Major collector and Arterial

City parking lots

Commercial

Lanes, spills, debris on road

Annually

Twice annually

Annually

Monthly

As required

Stormwater Management

Systems (SWMS)


Maintenance Activities

Catchbasins are currently cleaned on a five-year rotational

ti basis.

Minor collectors, residential roads and

lanes

Major collectors, arterials, Highway 16A

5yrs

2 yrs

Industrial, commercial and City parking

lots

2 yrs

Recommendation

That an annual inspection program be

undertaken to assess accumulated

deposits or contaminates exist in each

catchbasin

Stormwater Management

Systems (SWMS)


Maintenance Activities

Stormceptors/Oil Water Separators are neither inspected nor

maintained by the City

• Recommendation: That an annual inspection program be undertaken to

assess functionality of these items

• Manholes and storm mains are currently maintained on a

reactive maintenance basis only

• Recommendation: That manholes and mains be inspected on a five-year

rotational basis and 5% of the pipe system be inspected by CCTV annually

• Flow restrictors are neither inspected nor maintained

i Recommendation: That an annual inspection program be undertaken to

assess if the items are in good condition and functioning as intended.

Stormwater Management

Systems (SWMS)


Maintenance Activities

• Ditches and creeks are currently maintained on a reactive basis

only

• Recommendation: All ditches and creeks be inspected on a three-year

rotational basis

• Public culverts in ditches and roads are currently inspected and

cleaned every two years

• Recommendation: Maintain the current level of service

Stormwater Management

Systems (SWMS)


Maintenance Activities – Current LOS

Dry ponds are currently mowed on a bi-weekly basis and the inlet

and outfall are inspected twice yearly

Wet ponds are currently mowed on a bi-weekly basis and the inlet

and outfall are inspected twice yearly

Constructed Wetlands are currently mowed on a bi-weekly basis

and the inlet and outfall are inspected twice yearly

Stormwater Management

Systems (SWMS)


Maintenance Activities

In addition to the current LOS, we recommend inspections

of the following (SWMF) twice annually:

• Orifice plate for presence, proper size and function

• Animal grates on inlet and outfalls

• Inlet and outfall manholes for condition

• Overflow spillway

• Grass and landscaping for signs of erosion

• Check for pollutants (oil sheen)

• Check for sediment accumulation

Stormwater Management

Systems (SWMS)


Life Cycle Maintenance & Planning

Replacement cost of the storm

sewer system (excluding

=

SWMF’s

$40 - $50,000,000

Recommended allocation of

1% of the replacement cost

for a Life Cycle

Maintenance Fund

=

$4 - $500,000 annually

Stormwater Management

Systems (SWMS)


Capital Needs

Inventory of storm sewer infrastructure within the corporate limits is estimated

as follows:

Cost

Status

Upgrade ditch through Diamond Industrial N/a Completed

Construct SWMF in old sewage lagoon site $300,000 2007 (AMIP)

Upgrade culverts Hwy 16 King Street flows $1,200,000 2006 (AMIP)

Construct pond north of Hwy 16 $1,500,000 2006 (AMIP)

Construct ditches and SWMF $250,000 2007 (AMIP)

Drainage plan for Golf Course lands N/A Completed

Upgrade Dog Creek channel north of Grove Drive within Jesperdale By developer 2007-2008

Construct SWMF north of Grove Drive within Jesperdale By developer 2007-2008

Downtown Infrastructure Review

Upgrade underground storm pipe system $1,800,000 Review as

redevelopment

occurs

Construct SWMF $250,000000 2006 (AMIP)

Stormwater Management

Systems (SWMS)


Operating cost of Proposed LOS

The cost of the proposed Level of Service would be

approximately $60,000 in addition to our current operating

budget for Roads and Drainage

Stormwater Management

Systems (SWMS)


Next Steps…

1. Municipal Development Standards be reviewed and revised as required

– Spring 2006

2. Standard Development Agreements be reviewed and revised as

required – Spring 2006

3. City Administration to meet with Alberta Environment for input – Spring

2006

4. Pursue details of a Storm Water Utility in 2007 for Council consideration

in 2008

5. Finalize inventory and operating cost increases and present for Council

consideration as a new initiative for the 2007 operating budget.

6. Prepare appropriate maintenance policy – Early 2007

Stormwater Management

Systems (SWMS)


Questions?

Stormwater Management

Systems (SWMS)

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