Member of Conservation Ontario

Phosphorus offsetting: How new urban growth can support phosphorus reduction and innovative stormwater

management

Ben Longstaff, Mike Walters and Rob Baldwin

International River Symposium

October, 2018

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Lake Simcoe Region Conservation Authority

25km

*

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Lake Simcoe Region Conservation Authority

The challenge at hand…

- Approx. 31% of P loads from urban area (10% of watershed foot

print)

- Considerable proportion of urban area has no or limited:

▫ stormwater management (SWM); or

▫ opportunity (i.e. space) for conventional stormwater management

=uncontrolled stormwater

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Lake Simcoe Region Conservation Authority

The challenge at hand…

- Conventional SWM not providing expected benefits (e.g. poor maintenance, anoxic P release)

- Pond maintenance is not cheap & not a municipal priority

- Massive infrastructure deficit (e.g. estimated 56 ponds back to design level: $18.5 million)

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Lake Simcoe Region Conservation Authority

The challenge (and solution) at hand…

Significant urban growth planned within the Lake Simcoe Basin

2010 urban = 22,793 ha

Future at 2031 = 35,028 ha

Increase From 2014 = 9,990 ha

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Lake Simcoe Region Conservation Authority

Solutions needed!

1. New / re-development• Integrate principles of LID into site design to

reduce P loads and achieve water balance

2. Existing developed lands• Ensure existing SWM effectively maintained

• Retrofit existing urban areas with LID

How to fund retrofits while also driving down P loads from new development?

Transformation of stormwater management: from conventional SWM

to Low Impact Development (LID) / Water Sensitive Urban Design (WSUD)

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Lake Simcoe Region Conservation Authority

Lake Simcoe Phosphorus Offset Program (LSPOP)

• Offset study completed in 2014

• Not “trading” but a required offset

• New & re- development required to ensure that no P exported from site -Zero Export policy

• If required P loads reduction can not be achieved a charge per Kg is applied ($35,000/kgP)

• Funds used to retrofit existing uncontrolled urban areas

This policy provides strong incentive for innovation in the

design of new/re- urban development projects

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Lake Simcoe Region Conservation Authority

Where will the benefits be realized?• Projects will be selected based on

cost\benefit and ease of implementation

• Projects will initially be targeted on public lands (Future consideration of

private lands)

• Public/private landowners will be required to maintain the SWM

facilities in perpetuity.

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Lake Simcoe Region Conservation Authority

LSPOP Benefit Summary

Based on growth projections of 9,000 hectares and a charge of $35,000 kg a total of could $315 million could be realized to address urban sources.(Total P reduction = 10.7 T/y)

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Lake Simcoe Region Conservation Authority

Sheppards Bush Conservation Area - Aurora

Offset Ratios

• Offset ratios are used to manage risk / uncertainty

• Higher offset ratios are applied where BMP effectiveness cannot be easily quantified (i.e. higher uncertainty)

• Urban Stormwater 2.5 to 1,

(i.e. every 1kg not reduced on-site aim to reduce a 2.5kg offset at another location)

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Lake Simcoe Region Conservation Authority

LSPOP Example: New Development• The proposed development: 176 lots on a 9.2 ha site

• Estimated annual TP load from the new development is 13.8 kg/year.

• Thru LID stormwater best practices the proponent can control 75% of TP (10.3 kg/y)

• Additional P reduction needed to achieve net zero is 13.8 – 10.3 = 3.5 kg/y

• Apply offset ratio (2.5:1), 3.5 kg/year X 2.5 (offset ratio) = 8.8 kg/year

• Required Offset Purchase: 8.8 x $35,000 kg/y = $308,000

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Lake Simcoe Region Conservation Authority

Other Benefits of LSPOP: Not just P

• Water quantity

• Increased resilience to climate change

• Enhanced groundwater recharge

• Creation of green industry

• Facilities are aesthetically attractive, and provide opportunities for carbon offsetting.

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Lake Simcoe Region Conservation Authority

Putting the LSPOP into Practice Policy/approval framework:

- Enabled under amendment of the Ontario Water Resource Act

- LSRCA undertook significant consultation and has established good working relationship with industry

- Policy approved by LSRCA BOD (Effective January 1st

2018)

- Offsetting requirements became a condition of approval for all development

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Lake Simcoe Region Conservation Authority

Putting the LSPOP into Practice:

Implementing offsets:

• Multi-stakeholder committee: review and select offsetting projects

• LSRCA will oversee or implement selected projects

• SWM optimization modeling being undertaken to identify most appropriate offset location

• Ongoing tracking, audit and reporting of offset generation and transactions

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Lake Simcoe Region Conservation Authority

Secrets of success- Champion with tenacity (Mike Walters)

- A respected working relationship with development industry “fight for minimum or partner for maximums” (Rob Baldwin)

- Significant consultation

- Timing - property boom (offset cost minimal in relation to increase in market value)

- Win-win: Transfer of SWM review to LSRCA significantly increased approval turn-around time

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Lake Simcoe Region Conservation Authority

Other offsetting programs implemented

- Water Budget / Balance▫ Recharge policy under Source Water Protection plan

▫ Post to pre water budget must be maintained

▫ If not – Offsetting ($/M3 infiltrated) for projects in adjacent areas

- Ecological▫ In areas where there is “non-significant” loss of wetland or forest

▫ Goal is a “no net loss” through offsetting and compensation projects

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Lake Simcoe Region Conservation Authority

QUESTIONS