JPG1914S - Discussion & Conclusions

WISQQiH - Discussion & Conclusions

A. FINDINGS

These findings stem from preliminary analyses which were constrained by data availability, and as such, a more detailed investigation is recommended. We suggest that the methodology employed here may be successfully applied under circumstances where data availability is not an issue, whereby permitting a more rigorous analysis of the relationships between water quality and quantity and changing land use.

1. Water Quality and Changing Land Use
In terms of water quality, it was shown that while road salting practices have remained constant, the concentration of (unfiltered) Chloride in the Humber river has increased over the past few decades. Furthermore, we have demonstrated that Chloride concentration is well correlated, in a linear fashion, with suburban land use, and therefore, road density. Accordingly, dramatic increases in Chloride concentration were observed in the Pinegrove and Clairville areas.

2. Stream Flow and Changing Land Use
The impacts of changing land use on "hydrology" are perhaps more interesting. Preliminary analyses suggest that measurements of daily precipitation and discharge are poorly correlated such that large precipitation events are sometimes associated with low flow conditions (and vice-versa). Accordingly, we were unable to determine a relationship between a variety of "hydrologic" parameters (e.g. Run-Off Coefficients, Curve Numbers) and changing land use in the Humber Watershed. It was observed, however, that discharge and precipitation were well correlated in an urbanised watershed (for example, the Mimico Creek Watershed). In less urbanised subwatersheds it is apparent that analyses involving estimates of daily precipitation and discharge ignore the importance of processes which operate on shorter time scales (note: this becomes less important as the degree of urbanisation increases). Ideally, to assess the impacts of urbanisation on stream flow, one should investigate the lag between peak rainfall and peak discharge. In general, the lag should decrease with increasing urbanisation. Such an investigation requires high resolution data (e.g. at least hourly measurements of precipitation and discharge). Given our use of daily measurements, we can at least suggest, with some certainty, that the correlations between discharge and precipitation within each subwatershed do appear to be increasing through time and seem to be associated with decreasing density of forested lands.
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B. PLANNING ISSUES

1. From Hydrology to Policy
2. Vaughan's Woodlot Acquisition Program

FROM HYDROLOGY TO POLICY

One of the important questions that arises with regard to this study is how the results with regard to hydrology, and, for that matter, the results of hydrological research generally, can be applied to land use planning in order to prevent and remediate impacts to water quality and stream flow.

In fact, there are limited opportunities to integrate environmental information into land use decision-making in Ontario. To the extent that it is applied, it is through specialized federal and provincial agencies, and, more directly, through local planning offices - as there is an established tradition of Provincial governments delegating authority for land use planning to local authorities.
More specifically, in the Humber basin, land use planning is directed by:

(1) Special provincial legislation, such as the Niagara Escarpment Plan, or areas in which a 'provincial interest' has been declared, as is the case with designated wetlands for example,

(2) Conservation Authorities, which have a mandate to control development on hazard lands, such as flood plains,

(3) the local municipalities (although technically their decisions must conform with upper-tier regional plans (those of Regional Municipalities), in practice, the regions generally defer to the local councils and planning departments).
While provincial review of land use planning decisions was quite thorough in the past, this situation is changing as provincial agencies devolve development review responsibilities to the municipal level (Memorandum of Understanding Between the Province of Ontario and the Regional Municipality of Durham Regarding Municipal Plan Review 1996) - this is the first such agreement, and will serve as a template for agreements with other jurisdictions (Tony Wagner, Pers. comm.), as part of ongoing restructuring in the face of government cutbacks.

In effect, at the present time, local and even regional environmental considerations are the responsibility of municipal councils and bureaucrats. According to Tony Wagner of the Waterfront Regeneration Trust, those with environmental concerns must convince municipal bureaucrats and councillors to put protective measures into the local Official Plan (Pers. comm.).

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VAUGHAN'S WOODLOT ACQUISITION PROGRAM

An excellent example of the predominance of local jurisdiction in land use planning comes from the City of Vaughan in the Humber Watershed. It had a population of 25,000 people in 1981, rising to 129,000 in 1996, and projected to reach 265,000 by 2016.

Vaughan's Official Plan, officially known as Official Plan Amendment (OPA) #400, provides for the development of 3 new communities, housing a total population of 120,000 when complete. The new communities will encompass 2,600 hectares of rural land, which includes parts of the Oak Ridges Moraine as well as encompassing some of the headwaters of the Humber watershed.

Land designated as 'valleylands', 'tableland woodlots', and 'low-density moraine' are afforded some measure of protection from development as environmentally sensitive areas. The 'low-density moraine' regions are particularly relevant to hydrology, as they play a crucial role as groundwater recharge zones.

In Vaughan, the protection of tableland woodlots has been a contentious issue. The revised Official Plan seeks to protect 120 hectares of woodlots through a "Woodlot Acquisition Development Charge", a $1,000 levy per housing unit, the proceeds of which will be used by the City to acquire tableland woodlots (which presumably will include parts of the Moraine). This demonstrates the reality that environmental policy is not enough, implementation tools through each step of the approval process are required.

The MTRCA are pursuing a new initiative with regard to land use planning. They have assumed responsibility for establishing pre-development runoff rates to ensure that stormwater runoff from new development levels is conducive to an overall watershed approach. This has been implemented in the Don watershed. It has the effect of removing computation of pre-development flow estimates from developers, resulting in much lower flow estimates.

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Resources:
Greater Toronto Area Task Force 1996. Governing the City-Region. Report of the GTA Task Force. Toronto: Queen's Printer for Ontario.
Memorandum of Understanding Between The Province of Ontario and The Regional Municipality of Durham Regarding Municipal Plan Review.
Oak Ridges Moraine Technical Working Committee 1994. The Oak Ridges Moraine Area Strategy For The Greater Toronto Area; An Ecological Approach to the Protection and Management of the Oak Ridges Moraine. Toronto: Queen's Printer for Ontario.
Robinson, P.A. 1995. Protecting the Environment in a Rapidly Urbanizing Community. Plan Canada. 35, 6 (November): 22-25.
Royal Commission on the Future of the Toronto Waterfront 1991. Planning for Sustainability: Towards Integrating Environmental Protection Into Land-Use Planning. Toronto: Minister of Supply and Services.
Wagner, Tony. Personal communication.
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